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* [PATCH v6 00/24] erofs: promote erofs from staging
@ 2019-08-02 12:53 Gao Xiang
  2019-08-02 12:53 ` [PATCH v6 01/24] erofs: add on-disk layout Gao Xiang
                   ` (24 more replies)
  0 siblings, 25 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-02 12:53 UTC (permalink / raw)
  To: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds
  Cc: linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei, Gao Xiang

Hi folks,

We'd like to hear if there are potential suggestions or
maybe objections of EROFS upstreaming stuffs. If any,
we still have time and we can improve it in this round.

As related materials mentioned before, the goal of EROFS
filesystem is to save extra storage space with guaranteed
end-to-end performance for read-only files, which has better
performance over exist Linux compression filesystems based
on fixed-sized output compression and inplace decompression.
It even has better performance in a large compression ratio
range compared with generic uncompressed filesystems with
proper CPU-storage combinations. And we think this direction
is right and we have a dedicated kernel team working on it,
enough testers and beta / end users using it.

EROFS has been applied to 10+ million HUAWEI mobile phones 
(Yes, the number is still increasing by time) and it seems
like a success. It can be used in more wider scenarios.
We think it's useful for Linux / Android OS community and
it's the time moving out of staging.

EROFS is a self-contained filesystem driver. Although there
are still some TODOs, we will keep on developping / tuning
EROFS with the evolution of Linux kernel as the other
in-kernel filesystems.

Kindly share your comments about EROFS. Thank you in advance!

Thanks,
Gao Xiang

Changelog from v5:
 o keep up with "[PATCH v2] staging: erofs: updates according to erofs-outofstaging v4"
    https://lore.kernel.org/lkml/20190731155752.210602-1-gaoxiang25@huawei.com/
   which mainly addresses review comments from Chao:
  - keep the marco EROFS_IO_MAX_RETRIES_NOFAIL in internal.h;
  - kill a redundant NULL check in "__stagingpage_alloc";
  - add some descriptions in document about "use_vmap";
  - rearrange erofs_vmap of "staging: erofs: kill CONFIG_EROFS_FS_USE_VM_MAP_RAM";

 o all changes have been merged into staging tree, which are under staging-testing:
    https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git/log/?h=staging-testing

It can also be found in git at tag "erofs_2019-08-02" at:
 https://git.kernel.org/pub/scm/linux/kernel/git/xiang/linux.git/

and the latest fs code is available at:
 https://git.kernel.org/pub/scm/linux/kernel/git/xiang/linux.git/tree/fs/erofs?h=erofs-outofstaging

Changelog from v4:
 o rebase on Linus 5.3-rc1;

 o keep up with "staging: erofs: updates according to erofs-outofstaging v4"
   in order to get main code bit-for-bit identical with staging tree:
    https://lore.kernel.org/lkml/20190729065159.62378-1-gaoxiang25@huawei.com/

Changelog from v3:
 o use GPL-2.0-only for SPDX-License-Identifier suggested by Stephen;

 o kill all kconfig cache strategies and turn them into mount options
   "cache_strategy={disable|readahead|readaround}" suggested by Ted.
   As the first step, cached pages can still be usable after cache is
   disabled by remounting, and these pages will be fallen out over
   time, which can be refined in the later version if some requirement
   is needed. Update related document as well;

 o turn on CONFIG_EROFS_FS_SECURITY by default suggested by David;

 o kill CONFIG_EROFS_FS_IO_MAX_RETRIES and fold it into code; turn
   EROFS_FS_USE_VM_MAP_RAM into a module parameter ("use_vmap")
   suggested by David.

Changelog from v2:
 o kill sbi->dev_name and clean up all failure handling in
   fill_super() suggested by Al.
   Note that the initialzation of managed_cache is now moved
   after s_root is assigned since it's more preferred to iput()
   in .put_super() and all inodes should be evicted before
   the end of generic_shutdown_super(sb);

 o fold in the following staging patches (and thanks):
   staging: erofs:converting all 'unsigned' to 'unsigned int'
   staging: erofs: Remove function erofs_kill_sb()
    - However it was revoked due to erofs_kill_sb reused...
   staging: erofs: avoid opened loop codes
   staging: erofs: support bmap

 o move EROFS_SUPER_MAGIC_V1 from linux/fs/erofs/erofs_fs.h to
   include/uapi/linux/magic.h for userspace utilities.

Changelog from v1:
 o resend the whole filesystem into a patchset suggested by Greg;
 o code is more cleaner, especially for decompression frontend.

--8<----(original cover)----

Hi,

EROFS file system has been in Linux-staging for about a year.
It has been proved to be stable enough to move out of staging
by 10+ millions of HUAWEI Android mobile phones on the market
from EMUI 9.0.1, and it was promoted as one of the key features
of EMUI 9.1 [1], including P30(pro).

EROFS is a read-only file system designed to save extra storage
space with guaranteed end-to-end performance by applying
fixed-size output compression, inplace I/O and decompression
inplace technologies [2] to Linux filesystem.

In our observation, EROFS is one of the fastest Linux compression
filesystem using buffered I/O in the world. It will support
direct I/O in the future if needed. EROFS even has better read
performance in a large CR range compared with generic uncompressed
file systems with proper CPU-storage combination, which is
a reason why EROFS can be landed to speed up mobile phone
performance, and which can be probably used for other use cases
such as LiveCD and Docker image as well.

Currently EROFS supports 4k LZ4 fixed-size output compression
since LZ4 is the fastest widely-used decompression solution in
the world and 4k leads to unnoticable read amplification for
the worst case. More compression algorithms and cluster sizes
could be added later, which depends on the real requirement.

More information about EROFS itself are available at:
 Documentation/filesystems/erofs.txt
 https://kccncosschn19eng.sched.com/event/Nru2/erofs-an-introduction-and-our-smartphone-practice-xiang-gao-huawei

erofs-utils (mainly mkfs.erofs now) is available at
git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs-utils.git

Preliminary iomap support has been pending in EROFS mailing
list by Chao Yu. The key issue is that current iomap doesn't
support tail-end packing inline data yet, it should be
resolved later.

Thanks to many contributors in the last year, the code is more
clean and improved. We hope EROFS can be used in wider use cases
so let's promote erofs out of staging and enhance it more actively.

Kindly share comments about EROFS! We think EROFS is useful to
community as a part of Linux upstream.

Thank you very much,
Gao Xiang

[1] http://web.archive.org/web/20190627021241/https://consumer.huawei.com/en/emui/
[2] https://lore.kernel.org/lkml/20190624072258.28362-1-hsiangkao@aol.com/

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Pavel Machek <pavel@denx.de>
Cc: David Sterba <dsterba@suse.cz>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Darrick J . Wong <darrick.wong@oracle.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jan Kara <jack@suse.cz> 
Cc: Chao Yu <yuchao0@huawei.com>
Cc: Miao Xie <miaoxie@huawei.com>
Cc: Li Guifu <bluce.liguifu@huawei.com>
Cc: Fang Wei <fangwei1@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>

Gao Xiang (24):
  erofs: add on-disk layout
  erofs: add erofs in-memory stuffs
  erofs: add super block operations
  erofs: add raw address_space operations
  erofs: add inode operations
  erofs: support special inode
  erofs: add directory operations
  erofs: add namei functions
  erofs: support tracepoint
  erofs: update Kconfig and Makefile
  erofs: introduce xattr & posixacl support
  erofs: introduce tagged pointer
  erofs: add compression indexes support
  erofs: introduce superblock registration
  erofs: introduce erofs shrinker
  erofs: introduce workstation for decompression
  erofs: introduce per-CPU buffers implementation
  erofs: introduce pagevec for decompression subsystem
  erofs: add erofs_allocpage()
  erofs: introduce generic decompression backend
  erofs: introduce LZ4 decompression inplace
  erofs: introduce the decompression frontend
  erofs: introduce cached decompression
  erofs: add document

 Documentation/filesystems/erofs.txt |  225 +++++
 fs/Kconfig                          |    1 +
 fs/Makefile                         |    1 +
 fs/erofs/Kconfig                    |   98 ++
 fs/erofs/Makefile                   |   11 +
 fs/erofs/compress.h                 |   62 ++
 fs/erofs/data.c                     |  429 ++++++++
 fs/erofs/decompressor.c             |  360 +++++++
 fs/erofs/dir.c                      |  147 +++
 fs/erofs/erofs_fs.h                 |  316 ++++++
 fs/erofs/inode.c                    |  326 +++++++
 fs/erofs/internal.h                 |  554 +++++++++++
 fs/erofs/namei.c                    |  251 +++++
 fs/erofs/super.c                    |  666 +++++++++++++
 fs/erofs/tagptr.h                   |  110 +++
 fs/erofs/utils.c                    |  335 +++++++
 fs/erofs/xattr.c                    |  700 +++++++++++++
 fs/erofs/xattr.h                    |   94 ++
 fs/erofs/zdata.c                    | 1405 +++++++++++++++++++++++++++
 fs/erofs/zdata.h                    |  195 ++++
 fs/erofs/zmap.c                     |  462 +++++++++
 fs/erofs/zpvec.h                    |  159 +++
 include/trace/events/erofs.h        |  256 +++++
 include/uapi/linux/magic.h          |    1 +
 24 files changed, 7164 insertions(+)
 create mode 100644 Documentation/filesystems/erofs.txt
 create mode 100644 fs/erofs/Kconfig
 create mode 100644 fs/erofs/Makefile
 create mode 100644 fs/erofs/compress.h
 create mode 100644 fs/erofs/data.c
 create mode 100644 fs/erofs/decompressor.c
 create mode 100644 fs/erofs/dir.c
 create mode 100644 fs/erofs/erofs_fs.h
 create mode 100644 fs/erofs/inode.c
 create mode 100644 fs/erofs/internal.h
 create mode 100644 fs/erofs/namei.c
 create mode 100644 fs/erofs/super.c
 create mode 100644 fs/erofs/tagptr.h
 create mode 100644 fs/erofs/utils.c
 create mode 100644 fs/erofs/xattr.c
 create mode 100644 fs/erofs/xattr.h
 create mode 100644 fs/erofs/zdata.c
 create mode 100644 fs/erofs/zdata.h
 create mode 100644 fs/erofs/zmap.c
 create mode 100644 fs/erofs/zpvec.h
 create mode 100644 include/trace/events/erofs.h

-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v6 01/24] erofs: add on-disk layout
  2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
@ 2019-08-02 12:53 ` Gao Xiang
  2019-08-29  9:59   ` Christoph Hellwig
  2019-08-02 12:53 ` [PATCH v6 02/24] erofs: add erofs in-memory stuffs Gao Xiang
                   ` (23 subsequent siblings)
  24 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-08-02 12:53 UTC (permalink / raw)
  To: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds
  Cc: linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei, Gao Xiang

This commit adds the on-disk layout header file of erofs.
On-disk format is compatible with erofs-staging added in 4.19.

In addition, add EROFS_SUPER_MAGIC_V1 to magic.h.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/erofs_fs.h        | 316 +++++++++++++++++++++++++++++++++++++
 include/uapi/linux/magic.h |   1 +
 2 files changed, 317 insertions(+)
 create mode 100644 fs/erofs/erofs_fs.h

diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
new file mode 100644
index 000000000000..b307060dd220
--- /dev/null
+++ b/fs/erofs/erofs_fs.h
@@ -0,0 +1,316 @@
+/* SPDX-License-Identifier: GPL-2.0-only OR Apache-2.0 */
+/*
+ * linux/fs/erofs/erofs_fs.h
+ *
+ * Copyright (C) 2017-2018 HUAWEI, Inc.
+ *             http://www.huawei.com/
+ * Created by Gao Xiang <gaoxiang25@huawei.com>
+ */
+#ifndef __EROFS_FS_H
+#define __EROFS_FS_H
+
+/* Enhanced(Extended) ROM File System */
+#define EROFS_SUPER_OFFSET      1024
+
+/*
+ * Any bits that aren't in EROFS_ALL_REQUIREMENTS should be
+ * incompatible with this kernel version.
+ */
+#define EROFS_REQUIREMENT_LZ4_0PADDING	0x00000001
+#define EROFS_ALL_REQUIREMENTS		0
+
+struct erofs_super_block {
+/*  0 */__le32 magic;           /* in the little endian */
+/*  4 */__le32 checksum;        /* crc32c(super_block) */
+/*  8 */__le32 features;        /* (aka. feature_compat) */
+/* 12 */__u8 blkszbits;         /* support block_size == PAGE_SIZE only */
+/* 13 */__u8 reserved;
+
+/* 14 */__le16 root_nid;
+/* 16 */__le64 inos;            /* total valid ino # (== f_files - f_favail) */
+
+/* 24 */__le64 build_time;      /* inode v1 time derivation */
+/* 32 */__le32 build_time_nsec;
+/* 36 */__le32 blocks;          /* used for statfs */
+/* 40 */__le32 meta_blkaddr;
+/* 44 */__le32 xattr_blkaddr;
+/* 48 */__u8 uuid[16];          /* 128-bit uuid for volume */
+/* 64 */__u8 volume_name[16];   /* volume name */
+/* 80 */__le32 requirements;    /* (aka. feature_incompat) */
+
+/* 84 */__u8 reserved2[44];
+} __packed;                     /* 128 bytes */
+
+/*
+ * erofs inode data mapping:
+ * 0 - inode plain without inline data A:
+ * inode, [xattrs], ... | ... | no-holed data
+ * 1 - inode VLE compression B (legacy):
+ * inode, [xattrs], extents ... | ...
+ * 2 - inode plain with inline data C:
+ * inode, [xattrs], last_inline_data, ... | ... | no-holed data
+ * 3 - inode compression D:
+ * inode, [xattrs], map_header, extents ... | ...
+ * 4~7 - reserved
+ */
+enum {
+	EROFS_INODE_FLAT_PLAIN,
+	EROFS_INODE_FLAT_COMPRESSION_LEGACY,
+	EROFS_INODE_FLAT_INLINE,
+	EROFS_INODE_FLAT_COMPRESSION,
+	EROFS_INODE_LAYOUT_MAX
+};
+
+static bool erofs_inode_is_data_compressed(unsigned int datamode)
+{
+	if (datamode == EROFS_INODE_FLAT_COMPRESSION)
+		return true;
+	return datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY;
+}
+
+/* bit definitions of inode i_advise */
+#define EROFS_I_VERSION_BITS            1
+#define EROFS_I_DATA_MAPPING_BITS       3
+
+#define EROFS_I_VERSION_BIT             0
+#define EROFS_I_DATA_MAPPING_BIT        1
+
+struct erofs_inode_v1 {
+/*  0 */__le16 i_advise;
+
+/* 1 header + n-1 * 4 bytes inline xattr to keep continuity */
+/*  2 */__le16 i_xattr_icount;
+/*  4 */__le16 i_mode;
+/*  6 */__le16 i_nlink;
+/*  8 */__le32 i_size;
+/* 12 */__le32 i_reserved;
+/* 16 */union {
+		/* file total compressed blocks for data mapping 1 */
+		__le32 compressed_blocks;
+		__le32 raw_blkaddr;
+
+		/* for device files, used to indicate old/new device # */
+		__le32 rdev;
+	} i_u __packed;
+/* 20 */__le32 i_ino;           /* only used for 32-bit stat compatibility */
+/* 24 */__le16 i_uid;
+/* 26 */__le16 i_gid;
+/* 28 */__le32 i_reserved2;
+} __packed;
+
+/* 32 bytes on-disk inode */
+#define EROFS_INODE_LAYOUT_V1   0
+/* 64 bytes on-disk inode */
+#define EROFS_INODE_LAYOUT_V2   1
+
+struct erofs_inode_v2 {
+/*  0 */__le16 i_advise;
+
+/* 1 header + n-1 * 4 bytes inline xattr to keep continuity */
+/*  2 */__le16 i_xattr_icount;
+/*  4 */__le16 i_mode;
+/*  6 */__le16 i_reserved;
+/*  8 */__le64 i_size;
+/* 16 */union {
+		/* file total compressed blocks for data mapping 1 */
+		__le32 compressed_blocks;
+		__le32 raw_blkaddr;
+
+		/* for device files, used to indicate old/new device # */
+		__le32 rdev;
+	} i_u __packed;
+
+	/* only used for 32-bit stat compatibility */
+/* 20 */__le32 i_ino;
+
+/* 24 */__le32 i_uid;
+/* 28 */__le32 i_gid;
+/* 32 */__le64 i_ctime;
+/* 40 */__le32 i_ctime_nsec;
+/* 44 */__le32 i_nlink;
+/* 48 */__u8   i_reserved2[16];
+} __packed;                     /* 64 bytes */
+
+#define EROFS_MAX_SHARED_XATTRS         (128)
+/* h_shared_count between 129 ... 255 are special # */
+#define EROFS_SHARED_XATTR_EXTENT       (255)
+
+/*
+ * inline xattrs (n == i_xattr_icount):
+ * erofs_xattr_ibody_header(1) + (n - 1) * 4 bytes
+ *          12 bytes           /                   \
+ *                            /                     \
+ *                           /-----------------------\
+ *                           |  erofs_xattr_entries+ |
+ *                           +-----------------------+
+ * inline xattrs must starts in erofs_xattr_ibody_header,
+ * for read-only fs, no need to introduce h_refcount
+ */
+struct erofs_xattr_ibody_header {
+	__le32 h_reserved;
+	__u8   h_shared_count;
+	__u8   h_reserved2[7];
+	__le32 h_shared_xattrs[0];      /* shared xattr id array */
+} __packed;
+
+/* Name indexes */
+#define EROFS_XATTR_INDEX_USER              1
+#define EROFS_XATTR_INDEX_POSIX_ACL_ACCESS  2
+#define EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT 3
+#define EROFS_XATTR_INDEX_TRUSTED           4
+#define EROFS_XATTR_INDEX_LUSTRE            5
+#define EROFS_XATTR_INDEX_SECURITY          6
+
+/* xattr entry (for both inline & shared xattrs) */
+struct erofs_xattr_entry {
+	__u8   e_name_len;      /* length of name */
+	__u8   e_name_index;    /* attribute name index */
+	__le16 e_value_size;    /* size of attribute value */
+	/* followed by e_name and e_value */
+	char   e_name[0];       /* attribute name */
+} __packed;
+
+#define ondisk_xattr_ibody_size(count)	({\
+	u32 __count = le16_to_cpu(count); \
+	((__count) == 0) ? 0 : \
+	sizeof(struct erofs_xattr_ibody_header) + \
+		sizeof(__u32) * ((__count) - 1); })
+
+#define EROFS_XATTR_ALIGN(size) round_up(size, sizeof(struct erofs_xattr_entry))
+#define EROFS_XATTR_ENTRY_SIZE(entry) EROFS_XATTR_ALIGN( \
+	sizeof(struct erofs_xattr_entry) + \
+	(entry)->e_name_len + le16_to_cpu((entry)->e_value_size))
+
+/* available compression algorithm types */
+enum {
+	Z_EROFS_COMPRESSION_LZ4,
+	Z_EROFS_COMPRESSION_MAX
+};
+
+/*
+ * bit 0 : COMPACTED_2B indexes (0 - off; 1 - on)
+ *  e.g. for 4k logical cluster size,      4B        if compacted 2B is off;
+ *                                  (4B) + 2B + (4B) if compacted 2B is on.
+ */
+#define Z_EROFS_ADVISE_COMPACTED_2B_BIT         0
+
+#define Z_EROFS_ADVISE_COMPACTED_2B     (1 << Z_EROFS_ADVISE_COMPACTED_2B_BIT)
+
+struct z_erofs_map_header {
+	__le32	h_reserved1;
+	__le16	h_advise;
+	/*
+	 * bit 0-3 : algorithm type of head 1 (logical cluster type 01);
+	 * bit 4-7 : algorithm type of head 2 (logical cluster type 11).
+	 */
+	__u8	h_algorithmtype;
+	/*
+	 * bit 0-2 : logical cluster bits - 12, e.g. 0 for 4096;
+	 * bit 3-4 : (physical - logical) cluster bits of head 1:
+	 *       For example, if logical clustersize = 4096, 1 for 8192.
+	 * bit 5-7 : (physical - logical) cluster bits of head 2.
+	 */
+	__u8	h_clusterbits;
+};
+
+#define Z_EROFS_VLE_LEGACY_HEADER_PADDING       8
+
+/*
+ * Z_EROFS Variable-sized Logical Extent cluster type:
+ *    0 - literal (uncompressed) cluster
+ *    1 - compressed cluster (for the head logical cluster)
+ *    2 - compressed cluster (for the other logical clusters)
+ *
+ * In detail,
+ *    0 - literal (uncompressed) cluster,
+ *        di_advise = 0
+ *        di_clusterofs = the literal data offset of the cluster
+ *        di_blkaddr = the blkaddr of the literal cluster
+ *
+ *    1 - compressed cluster (for the head logical cluster)
+ *        di_advise = 1
+ *        di_clusterofs = the decompressed data offset of the cluster
+ *        di_blkaddr = the blkaddr of the compressed cluster
+ *
+ *    2 - compressed cluster (for the other logical clusters)
+ *        di_advise = 2
+ *        di_clusterofs =
+ *           the decompressed data offset in its own head cluster
+ *        di_u.delta[0] = distance to its corresponding head cluster
+ *        di_u.delta[1] = distance to its corresponding tail cluster
+ *                (di_advise could be 0, 1 or 2)
+ */
+enum {
+	Z_EROFS_VLE_CLUSTER_TYPE_PLAIN,
+	Z_EROFS_VLE_CLUSTER_TYPE_HEAD,
+	Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD,
+	Z_EROFS_VLE_CLUSTER_TYPE_RESERVED,
+	Z_EROFS_VLE_CLUSTER_TYPE_MAX
+};
+
+#define Z_EROFS_VLE_DI_CLUSTER_TYPE_BITS        2
+#define Z_EROFS_VLE_DI_CLUSTER_TYPE_BIT         0
+
+struct z_erofs_vle_decompressed_index {
+	__le16 di_advise;
+	/* where to decompress in the head cluster */
+	__le16 di_clusterofs;
+
+	union {
+		/* for the head cluster */
+		__le32 blkaddr;
+		/*
+		 * for the rest clusters
+		 * eg. for 4k page-sized cluster, maximum 4K*64k = 256M)
+		 * [0] - pointing to the head cluster
+		 * [1] - pointing to the tail cluster
+		 */
+		__le16 delta[2];
+	} di_u __packed;		/* 8 bytes */
+} __packed;
+
+#define Z_EROFS_VLE_LEGACY_INDEX_ALIGN(size) \
+	(round_up(size, sizeof(struct z_erofs_vle_decompressed_index)) + \
+	 sizeof(struct z_erofs_map_header) + Z_EROFS_VLE_LEGACY_HEADER_PADDING)
+
+/* dirent sorts in alphabet order, thus we can do binary search */
+struct erofs_dirent {
+	__le64 nid;     /*  0, node number */
+	__le16 nameoff; /*  8, start offset of file name */
+	__u8 file_type; /* 10, file type */
+	__u8 reserved;  /* 11, reserved */
+} __packed;
+
+/* file types used in inode_info->flags */
+enum {
+	EROFS_FT_UNKNOWN,
+	EROFS_FT_REG_FILE,
+	EROFS_FT_DIR,
+	EROFS_FT_CHRDEV,
+	EROFS_FT_BLKDEV,
+	EROFS_FT_FIFO,
+	EROFS_FT_SOCK,
+	EROFS_FT_SYMLINK,
+	EROFS_FT_MAX
+};
+
+#define EROFS_NAME_LEN      255
+
+/* check the EROFS on-disk layout strictly at compile time */
+static inline void erofs_check_ondisk_layout_definitions(void)
+{
+	BUILD_BUG_ON(sizeof(struct erofs_super_block) != 128);
+	BUILD_BUG_ON(sizeof(struct erofs_inode_v1) != 32);
+	BUILD_BUG_ON(sizeof(struct erofs_inode_v2) != 64);
+	BUILD_BUG_ON(sizeof(struct erofs_xattr_ibody_header) != 12);
+	BUILD_BUG_ON(sizeof(struct erofs_xattr_entry) != 4);
+	BUILD_BUG_ON(sizeof(struct z_erofs_map_header) != 8);
+	BUILD_BUG_ON(sizeof(struct z_erofs_vle_decompressed_index) != 8);
+	BUILD_BUG_ON(sizeof(struct erofs_dirent) != 12);
+
+	BUILD_BUG_ON(BIT(Z_EROFS_VLE_DI_CLUSTER_TYPE_BITS) <
+		     Z_EROFS_VLE_CLUSTER_TYPE_MAX - 1);
+}
+
+#endif
+
diff --git a/include/uapi/linux/magic.h b/include/uapi/linux/magic.h
index 1274c692e59c..903cc2d2750b 100644
--- a/include/uapi/linux/magic.h
+++ b/include/uapi/linux/magic.h
@@ -19,6 +19,7 @@
 #define SQUASHFS_MAGIC		0x73717368
 #define ECRYPTFS_SUPER_MAGIC	0xf15f
 #define EFS_SUPER_MAGIC		0x414A53
+#define EROFS_SUPER_MAGIC_V1	0xE0F5E1E2
 #define EXT2_SUPER_MAGIC	0xEF53
 #define EXT3_SUPER_MAGIC	0xEF53
 #define XENFS_SUPER_MAGIC	0xabba1974
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v6 02/24] erofs: add erofs in-memory stuffs
  2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
  2019-08-02 12:53 ` [PATCH v6 01/24] erofs: add on-disk layout Gao Xiang
@ 2019-08-02 12:53 ` Gao Xiang
  2019-08-02 12:53 ` [PATCH v6 03/24] erofs: add super block operations Gao Xiang
                   ` (22 subsequent siblings)
  24 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-02 12:53 UTC (permalink / raw)
  To: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds
  Cc: linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei, Gao Xiang

 - erofs_sb_info:
   contains erofs-specific in-memory information.

 - erofs_vnode:
   contains vfs_inode and other fs-specific information.
   same as super block, the only one in-memory definition exists.

 - erofs_map_blocks
   Logical to physical block mapping, used by erofs_map_blocks().

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/internal.h | 356 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 356 insertions(+)
 create mode 100644 fs/erofs/internal.h

diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
new file mode 100644
index 000000000000..2c94149d7218
--- /dev/null
+++ b/fs/erofs/internal.h
@@ -0,0 +1,356 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * linux/fs/erofs/internal.h
+ *
+ * Copyright (C) 2017-2018 HUAWEI, Inc.
+ *             http://www.huawei.com/
+ * Created by Gao Xiang <gaoxiang25@huawei.com>
+ */
+#ifndef __EROFS_INTERNAL_H
+#define __EROFS_INTERNAL_H
+
+#include <linux/fs.h>
+#include <linux/dcache.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/bio.h>
+#include <linux/buffer_head.h>
+#include <linux/cleancache.h>
+#include <linux/magic.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include "erofs_fs.h"
+
+/* redefine pr_fmt "erofs: " */
+#undef pr_fmt
+#define pr_fmt(fmt) "erofs: " fmt
+
+#define errln(x, ...)   pr_err(x "\n", ##__VA_ARGS__)
+#define infoln(x, ...)  pr_info(x "\n", ##__VA_ARGS__)
+#ifdef CONFIG_EROFS_FS_DEBUG
+#define debugln(x, ...) pr_debug(x "\n", ##__VA_ARGS__)
+#define DBG_BUGON               BUG_ON
+#else
+#define debugln(x, ...)         ((void)0)
+#define DBG_BUGON(x)            ((void)(x))
+#endif	/* !CONFIG_EROFS_FS_DEBUG */
+
+enum {
+	FAULT_KMALLOC,
+	FAULT_READ_IO,
+	FAULT_MAX,
+};
+
+#ifdef CONFIG_EROFS_FAULT_INJECTION
+extern const char *erofs_fault_name[FAULT_MAX];
+#define IS_FAULT_SET(fi, type) ((fi)->inject_type & (1 << (type)))
+
+struct erofs_fault_info {
+	atomic_t inject_ops;
+	unsigned int inject_rate;
+	unsigned int inject_type;
+};
+#endif	/* CONFIG_EROFS_FAULT_INJECTION */
+
+/* EROFS_SUPER_MAGIC_V1 to represent the whole file system */
+#define EROFS_SUPER_MAGIC   EROFS_SUPER_MAGIC_V1
+
+typedef u64 erofs_nid_t;
+typedef u64 erofs_off_t;
+/* data type for filesystem-wide blocks number */
+typedef u32 erofs_blk_t;
+
+struct erofs_sb_info {
+	u32 blocks;
+	u32 meta_blkaddr;
+
+	/* inode slot unit size in bit shift */
+	unsigned char islotbits;
+
+	u32 build_time_nsec;
+	u64 build_time;
+
+	/* what we really care is nid, rather than ino.. */
+	erofs_nid_t root_nid;
+	/* used for statfs, f_files - f_favail */
+	u64 inos;
+
+	u8 uuid[16];                    /* 128-bit uuid for volume */
+	u8 volume_name[16];             /* volume name */
+	u32 requirements;
+
+	unsigned int mount_opt;
+
+#ifdef CONFIG_EROFS_FAULT_INJECTION
+	struct erofs_fault_info fault_info;	/* For fault injection */
+#endif
+};
+
+#ifdef CONFIG_EROFS_FAULT_INJECTION
+#define erofs_show_injection_info(type)					\
+	infoln("inject %s in %s of %pS", erofs_fault_name[type],        \
+		__func__, __builtin_return_address(0))
+
+static inline bool time_to_inject(struct erofs_sb_info *sbi, int type)
+{
+	struct erofs_fault_info *ffi = &sbi->fault_info;
+
+	if (!ffi->inject_rate)
+		return false;
+
+	if (!IS_FAULT_SET(ffi, type))
+		return false;
+
+	atomic_inc(&ffi->inject_ops);
+	if (atomic_read(&ffi->inject_ops) >= ffi->inject_rate) {
+		atomic_set(&ffi->inject_ops, 0);
+		return true;
+	}
+	return false;
+}
+#else
+static inline bool time_to_inject(struct erofs_sb_info *sbi, int type)
+{
+	return false;
+}
+
+static inline void erofs_show_injection_info(int type)
+{
+}
+#endif	/* !CONFIG_EROFS_FAULT_INJECTION */
+
+static inline void *erofs_kmalloc(struct erofs_sb_info *sbi,
+					size_t size, gfp_t flags)
+{
+	if (time_to_inject(sbi, FAULT_KMALLOC)) {
+		erofs_show_injection_info(FAULT_KMALLOC);
+		return NULL;
+	}
+	return kmalloc(size, flags);
+}
+
+#define EROFS_SB(sb) ((struct erofs_sb_info *)(sb)->s_fs_info)
+#define EROFS_I_SB(inode) ((struct erofs_sb_info *)(inode)->i_sb->s_fs_info)
+
+/* Mount flags set via mount options or defaults */
+#define EROFS_MOUNT_FAULT_INJECTION	0x00000040
+
+#define clear_opt(sbi, option)	((sbi)->mount_opt &= ~EROFS_MOUNT_##option)
+#define set_opt(sbi, option)	((sbi)->mount_opt |= EROFS_MOUNT_##option)
+#define test_opt(sbi, option)	((sbi)->mount_opt & EROFS_MOUNT_##option)
+
+/* we strictly follow PAGE_SIZE and no buffer head yet */
+#define LOG_BLOCK_SIZE		PAGE_SHIFT
+
+#undef LOG_SECTORS_PER_BLOCK
+#define LOG_SECTORS_PER_BLOCK	(PAGE_SHIFT - 9)
+
+#undef SECTORS_PER_BLOCK
+#define SECTORS_PER_BLOCK	(1 << SECTORS_PER_BLOCK)
+
+#define EROFS_BLKSIZ		(1 << LOG_BLOCK_SIZE)
+
+#if (EROFS_BLKSIZ % 4096 || !EROFS_BLKSIZ)
+#error erofs cannot be used in this platform
+#endif
+
+#define EROFS_IO_MAX_RETRIES_NOFAIL     5
+
+#define ROOT_NID(sb)		((sb)->root_nid)
+
+#define erofs_blknr(addr)       ((addr) / EROFS_BLKSIZ)
+#define erofs_blkoff(addr)      ((addr) % EROFS_BLKSIZ)
+#define blknr_to_addr(nr)       ((erofs_off_t)(nr) * EROFS_BLKSIZ)
+
+static inline erofs_off_t iloc(struct erofs_sb_info *sbi, erofs_nid_t nid)
+{
+	return blknr_to_addr(sbi->meta_blkaddr) + (nid << sbi->islotbits);
+}
+
+struct erofs_vnode {
+	erofs_nid_t nid;
+
+	unsigned char datamode;
+	unsigned char inode_isize;
+	unsigned short xattr_isize;
+
+	erofs_blk_t raw_blkaddr;
+	/* the corresponding vfs inode */
+	struct inode vfs_inode;
+};
+
+#define EROFS_V(ptr)	\
+	container_of(ptr, struct erofs_vnode, vfs_inode)
+
+#define __inode_advise(x, bit, bits) \
+	(((x) >> (bit)) & ((1 << (bits)) - 1))
+
+#define __inode_version(advise)	\
+	__inode_advise(advise, EROFS_I_VERSION_BIT,	\
+		EROFS_I_VERSION_BITS)
+
+#define __inode_data_mapping(advise)	\
+	__inode_advise(advise, EROFS_I_DATA_MAPPING_BIT,\
+		EROFS_I_DATA_MAPPING_BITS)
+
+static inline unsigned long inode_datablocks(struct inode *inode)
+{
+	/* since i_size cannot be changed */
+	return DIV_ROUND_UP(inode->i_size, EROFS_BLKSIZ);
+}
+
+static inline bool is_inode_layout_compression(struct inode *inode)
+{
+	return erofs_inode_is_data_compressed(EROFS_V(inode)->datamode);
+}
+
+static inline bool is_inode_flat_inline(struct inode *inode)
+{
+	return EROFS_V(inode)->datamode == EROFS_INODE_FLAT_INLINE;
+}
+
+extern const struct super_operations erofs_sops;
+
+extern const struct address_space_operations erofs_raw_access_aops;
+
+/*
+ * Logical to physical block mapping, used by erofs_map_blocks()
+ *
+ * Different with other file systems, it is used for 2 access modes:
+ *
+ * 1) RAW access mode:
+ *
+ * Users pass a valid (m_lblk, m_lofs -- usually 0) pair,
+ * and get the valid m_pblk, m_pofs and the longest m_len(in bytes).
+ *
+ * Note that m_lblk in the RAW access mode refers to the number of
+ * the compressed ondisk block rather than the uncompressed
+ * in-memory block for the compressed file.
+ *
+ * m_pofs equals to m_lofs except for the inline data page.
+ *
+ * 2) Normal access mode:
+ *
+ * If the inode is not compressed, it has no difference with
+ * the RAW access mode. However, if the inode is compressed,
+ * users should pass a valid (m_lblk, m_lofs) pair, and get
+ * the needed m_pblk, m_pofs, m_len to get the compressed data
+ * and the updated m_lblk, m_lofs which indicates the start
+ * of the corresponding uncompressed data in the file.
+ */
+enum {
+	BH_Zipped = BH_PrivateStart,
+	BH_FullMapped,
+};
+
+/* Has a disk mapping */
+#define EROFS_MAP_MAPPED	(1 << BH_Mapped)
+/* Located in metadata (could be copied from bd_inode) */
+#define EROFS_MAP_META		(1 << BH_Meta)
+
+struct erofs_map_blocks {
+	erofs_off_t m_pa, m_la;
+	u64 m_plen, m_llen;
+
+	unsigned int m_flags;
+
+	struct page *mpage;
+};
+
+/* Flags used by erofs_map_blocks() */
+#define EROFS_GET_BLOCKS_RAW    0x0001
+
+/* data.c */
+static inline struct bio *erofs_grab_bio(struct super_block *sb,
+					 erofs_blk_t blkaddr,
+					 unsigned int nr_pages,
+					 void *bi_private, bio_end_io_t endio,
+					 bool nofail)
+{
+	const gfp_t gfp = GFP_NOIO;
+	struct bio *bio;
+
+	do {
+		if (nr_pages == 1) {
+			bio = bio_alloc(gfp | (nofail ? __GFP_NOFAIL : 0), 1);
+			if (unlikely(!bio)) {
+				DBG_BUGON(nofail);
+				return ERR_PTR(-ENOMEM);
+			}
+			break;
+		}
+		bio = bio_alloc(gfp, nr_pages);
+		nr_pages /= 2;
+	} while (unlikely(!bio));
+
+	bio->bi_end_io = endio;
+	bio_set_dev(bio, sb->s_bdev);
+	bio->bi_iter.bi_sector = (sector_t)blkaddr << LOG_SECTORS_PER_BLOCK;
+	bio->bi_private = bi_private;
+	return bio;
+}
+
+static inline void __submit_bio(struct bio *bio, unsigned int op,
+				unsigned int op_flags)
+{
+	bio_set_op_attrs(bio, op, op_flags);
+	submit_bio(bio);
+}
+
+struct page *__erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr,
+				   bool prio, bool nofail);
+
+static inline struct page *erofs_get_meta_page(struct super_block *sb,
+	erofs_blk_t blkaddr, bool prio)
+{
+	return __erofs_get_meta_page(sb, blkaddr, prio, false);
+}
+
+int erofs_map_blocks(struct inode *, struct erofs_map_blocks *, int);
+
+static inline struct page *erofs_get_inline_page(struct inode *inode,
+						 erofs_blk_t blkaddr)
+{
+	return erofs_get_meta_page(inode->i_sb, blkaddr,
+				   S_ISDIR(inode->i_mode));
+}
+
+/* inode.c */
+static inline unsigned long erofs_inode_hash(erofs_nid_t nid)
+{
+#if BITS_PER_LONG == 32
+	return (nid >> 32) ^ (nid & 0xffffffff);
+#else
+	return nid;
+#endif
+}
+
+extern const struct inode_operations erofs_generic_iops;
+extern const struct inode_operations erofs_symlink_iops;
+extern const struct inode_operations erofs_fast_symlink_iops;
+
+static inline void set_inode_fast_symlink(struct inode *inode)
+{
+	inode->i_op = &erofs_fast_symlink_iops;
+}
+
+static inline bool is_inode_fast_symlink(struct inode *inode)
+{
+	return inode->i_op == &erofs_fast_symlink_iops;
+}
+
+struct inode *erofs_iget(struct super_block *sb, erofs_nid_t nid, bool dir);
+int erofs_getattr(const struct path *path, struct kstat *stat,
+		  u32 request_mask, unsigned int query_flags);
+
+/* namei.c */
+extern const struct inode_operations erofs_dir_iops;
+
+int erofs_namei(struct inode *dir, struct qstr *name,
+		erofs_nid_t *nid, unsigned int *d_type);
+
+/* dir.c */
+extern const struct file_operations erofs_dir_fops;
+
+#endif	/* __EROFS_INTERNAL_H */
+
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v6 03/24] erofs: add super block operations
  2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
  2019-08-02 12:53 ` [PATCH v6 01/24] erofs: add on-disk layout Gao Xiang
  2019-08-02 12:53 ` [PATCH v6 02/24] erofs: add erofs in-memory stuffs Gao Xiang
@ 2019-08-02 12:53 ` Gao Xiang
  2019-08-29 10:15   ` Christoph Hellwig
  2019-08-02 12:53 ` [PATCH v6 04/24] erofs: add raw address_space operations Gao Xiang
                   ` (21 subsequent siblings)
  24 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-08-02 12:53 UTC (permalink / raw)
  To: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds
  Cc: linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei, Gao Xiang

This commit adds erofs super block operations, including (u)mount,
remount_fs, show_options, statfs, in addition to some private
icache management functions.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/super.c | 437 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 437 insertions(+)
 create mode 100644 fs/erofs/super.c

diff --git a/fs/erofs/super.c b/fs/erofs/super.c
new file mode 100644
index 000000000000..cd4bd6f48173
--- /dev/null
+++ b/fs/erofs/super.c
@@ -0,0 +1,437 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/fs/erofs/super.c
+ *
+ * Copyright (C) 2017-2018 HUAWEI, Inc.
+ *             http://www.huawei.com/
+ * Created by Gao Xiang <gaoxiang25@huawei.com>
+ */
+#include <linux/module.h>
+#include <linux/buffer_head.h>
+#include <linux/statfs.h>
+#include <linux/parser.h>
+#include <linux/seq_file.h>
+#include "internal.h"
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/erofs.h>
+
+static struct kmem_cache *erofs_inode_cachep __read_mostly;
+
+static void init_once(void *ptr)
+{
+	struct erofs_vnode *vi = ptr;
+
+	inode_init_once(&vi->vfs_inode);
+}
+
+static int __init erofs_init_inode_cache(void)
+{
+	erofs_inode_cachep = kmem_cache_create("erofs_inode",
+					       sizeof(struct erofs_vnode), 0,
+					       SLAB_RECLAIM_ACCOUNT,
+					       init_once);
+
+	return erofs_inode_cachep ? 0 : -ENOMEM;
+}
+
+static void erofs_exit_inode_cache(void)
+{
+	kmem_cache_destroy(erofs_inode_cachep);
+}
+
+static struct inode *alloc_inode(struct super_block *sb)
+{
+	struct erofs_vnode *vi =
+		kmem_cache_alloc(erofs_inode_cachep, GFP_KERNEL);
+
+	if (!vi)
+		return NULL;
+
+	/* zero out everything except vfs_inode */
+	memset(vi, 0, offsetof(struct erofs_vnode, vfs_inode));
+	return &vi->vfs_inode;
+}
+
+static void free_inode(struct inode *inode)
+{
+	struct erofs_vnode *vi = EROFS_V(inode);
+
+	/* be careful RCU symlink path (see ext4_inode_info->i_data)! */
+	if (is_inode_fast_symlink(inode))
+		kfree(inode->i_link);
+
+	kmem_cache_free(erofs_inode_cachep, vi);
+}
+
+static bool check_layout_compatibility(struct super_block *sb,
+				       struct erofs_super_block *layout)
+{
+	const unsigned int requirements = le32_to_cpu(layout->requirements);
+
+	EROFS_SB(sb)->requirements = requirements;
+
+	/* check if current kernel meets all mandatory requirements */
+	if (requirements & (~EROFS_ALL_REQUIREMENTS)) {
+		errln("unidentified requirements %x, please upgrade kernel version",
+		      requirements & ~EROFS_ALL_REQUIREMENTS);
+		return false;
+	}
+	return true;
+}
+
+static int superblock_read(struct super_block *sb)
+{
+	struct erofs_sb_info *sbi;
+	struct buffer_head *bh;
+	struct erofs_super_block *layout;
+	unsigned int blkszbits;
+	int ret;
+
+	bh = sb_bread(sb, 0);
+
+	if (!bh) {
+		errln("cannot read erofs superblock");
+		return -EIO;
+	}
+
+	sbi = EROFS_SB(sb);
+	layout = (struct erofs_super_block *)((u8 *)bh->b_data
+		 + EROFS_SUPER_OFFSET);
+
+	ret = -EINVAL;
+	if (le32_to_cpu(layout->magic) != EROFS_SUPER_MAGIC_V1) {
+		errln("cannot find valid erofs superblock");
+		goto out;
+	}
+
+	blkszbits = layout->blkszbits;
+	/* 9(512 bytes) + LOG_SECTORS_PER_BLOCK == LOG_BLOCK_SIZE */
+	if (unlikely(blkszbits != LOG_BLOCK_SIZE)) {
+		errln("blksize %u isn't supported on this platform",
+		      1 << blkszbits);
+		goto out;
+	}
+
+	if (!check_layout_compatibility(sb, layout))
+		goto out;
+
+	sbi->blocks = le32_to_cpu(layout->blocks);
+	sbi->meta_blkaddr = le32_to_cpu(layout->meta_blkaddr);
+	sbi->islotbits = ffs(sizeof(struct erofs_inode_v1)) - 1;
+	sbi->root_nid = le16_to_cpu(layout->root_nid);
+	sbi->inos = le64_to_cpu(layout->inos);
+
+	sbi->build_time = le64_to_cpu(layout->build_time);
+	sbi->build_time_nsec = le32_to_cpu(layout->build_time_nsec);
+
+	memcpy(&sb->s_uuid, layout->uuid, sizeof(layout->uuid));
+	memcpy(sbi->volume_name, layout->volume_name,
+	       sizeof(layout->volume_name));
+
+	ret = 0;
+out:
+	brelse(bh);
+	return ret;
+}
+
+#ifdef CONFIG_EROFS_FAULT_INJECTION
+const char *erofs_fault_name[FAULT_MAX] = {
+	[FAULT_KMALLOC]		= "kmalloc",
+	[FAULT_READ_IO]		= "read IO error",
+};
+
+static void __erofs_build_fault_attr(struct erofs_sb_info *sbi,
+				     unsigned int rate)
+{
+	struct erofs_fault_info *ffi = &sbi->fault_info;
+
+	if (rate) {
+		atomic_set(&ffi->inject_ops, 0);
+		ffi->inject_rate = rate;
+		ffi->inject_type = (1 << FAULT_MAX) - 1;
+	} else {
+		memset(ffi, 0, sizeof(struct erofs_fault_info));
+	}
+
+	set_opt(sbi, FAULT_INJECTION);
+}
+
+static int erofs_build_fault_attr(struct erofs_sb_info *sbi,
+				  substring_t *args)
+{
+	int rate = 0;
+
+	if (args->from && match_int(args, &rate))
+		return -EINVAL;
+
+	__erofs_build_fault_attr(sbi, rate);
+	return 0;
+}
+
+static unsigned int erofs_get_fault_rate(struct erofs_sb_info *sbi)
+{
+	return sbi->fault_info.inject_rate;
+}
+#else
+static void __erofs_build_fault_attr(struct erofs_sb_info *sbi,
+				     unsigned int rate)
+{
+}
+
+static int erofs_build_fault_attr(struct erofs_sb_info *sbi,
+				  substring_t *args)
+{
+	infoln("fault_injection options not supported");
+	return 0;
+}
+
+static unsigned int erofs_get_fault_rate(struct erofs_sb_info *sbi)
+{
+	return 0;
+}
+#endif
+
+/* set up default EROFS parameters */
+static void default_options(struct erofs_sb_info *sbi)
+{
+}
+
+enum {
+	Opt_fault_injection,
+	Opt_err
+};
+
+static match_table_t erofs_tokens = {
+	{Opt_fault_injection, "fault_injection=%u"},
+	{Opt_err, NULL}
+};
+
+static int parse_options(struct super_block *sb, char *options)
+{
+	substring_t args[MAX_OPT_ARGS];
+	char *p;
+	int err;
+
+	if (!options)
+		return 0;
+
+	while ((p = strsep(&options, ","))) {
+		int token;
+
+		if (!*p)
+			continue;
+
+		args[0].to = args[0].from = NULL;
+		token = match_token(p, erofs_tokens, args);
+
+		switch (token) {
+		case Opt_fault_injection:
+			err = erofs_build_fault_attr(EROFS_SB(sb), args);
+			if (err)
+				return err;
+			break;
+		default:
+			errln("Unrecognized mount option \"%s\" or missing value", p);
+			return -EINVAL;
+		}
+	}
+	return 0;
+}
+
+static int erofs_fill_super(struct super_block *sb, void *data, int silent)
+{
+	struct inode *inode;
+	struct erofs_sb_info *sbi;
+	int err;
+
+	infoln("fill_super, device -> %s", sb->s_id);
+	infoln("options -> %s", (char *)data);
+
+	sb->s_magic = EROFS_SUPER_MAGIC;
+
+	if (unlikely(!sb_set_blocksize(sb, EROFS_BLKSIZ))) {
+		errln("failed to set erofs blksize");
+		return -EINVAL;
+	}
+
+	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
+	if (unlikely(!sbi))
+		return -ENOMEM;
+
+	sb->s_fs_info = sbi;
+	err = superblock_read(sb);
+	if (err)
+		return err;
+
+	sb->s_flags |= SB_RDONLY | SB_NOATIME;
+	sb->s_maxbytes = MAX_LFS_FILESIZE;
+	sb->s_time_gran = 1;
+
+	sb->s_op = &erofs_sops;
+
+	/* set erofs default mount options */
+	default_options(sbi);
+
+	err = parse_options(sb, data);
+	if (unlikely(err))
+		return err;
+
+	if (!silent)
+		infoln("root inode @ nid %llu", ROOT_NID(sbi));
+
+	/* get the root inode */
+	inode = erofs_iget(sb, ROOT_NID(sbi), true);
+	if (IS_ERR(inode))
+		return PTR_ERR(inode);
+
+	if (unlikely(!S_ISDIR(inode->i_mode))) {
+		errln("rootino(nid %llu) is not a directory(i_mode %o)",
+		      ROOT_NID(sbi), inode->i_mode);
+		iput(inode);
+		return -EINVAL;
+	}
+
+	sb->s_root = d_make_root(inode);
+	if (unlikely(!sb->s_root))
+		return -ENOMEM;
+
+	if (!silent)
+		infoln("mounted on %s with opts: %s.", sb->s_id, (char *)data);
+	return 0;
+}
+
+static struct dentry *erofs_mount(struct file_system_type *fs_type, int flags,
+				  const char *dev_name, void *data)
+{
+	return mount_bdev(fs_type, flags, dev_name, data, erofs_fill_super);
+}
+
+/*
+ * could be triggered after deactivate_locked_super()
+ * is called, thus including umount and failed to initialize.
+ */
+static void erofs_kill_sb(struct super_block *sb)
+{
+	struct erofs_sb_info *sbi;
+
+	WARN_ON(sb->s_magic != EROFS_SUPER_MAGIC);
+	infoln("unmounting for %s", sb->s_id);
+
+	kill_block_super(sb);
+
+	sbi = EROFS_SB(sb);
+	if (!sbi)
+		return;
+	kfree(sbi);
+	sb->s_fs_info = NULL;
+}
+
+static struct file_system_type erofs_fs_type = {
+	.owner          = THIS_MODULE,
+	.name           = "erofs",
+	.mount          = erofs_mount,
+	.kill_sb        = erofs_kill_sb,
+	.fs_flags       = FS_REQUIRES_DEV,
+};
+MODULE_ALIAS_FS("erofs");
+
+static int __init erofs_module_init(void)
+{
+	int err;
+
+	erofs_check_ondisk_layout_definitions();
+	infoln("initializing erofs " EROFS_VERSION);
+
+	err = erofs_init_inode_cache();
+	if (err)
+		goto icache_err;
+
+	err = register_filesystem(&erofs_fs_type);
+	if (err)
+		goto fs_err;
+
+	infoln("successfully to initialize erofs");
+	return 0;
+
+fs_err:
+	erofs_exit_inode_cache();
+icache_err:
+	return err;
+}
+
+static void __exit erofs_module_exit(void)
+{
+	unregister_filesystem(&erofs_fs_type);
+	erofs_exit_inode_cache();
+	infoln("successfully finalize erofs");
+}
+
+/* get filesystem statistics */
+static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct super_block *sb = dentry->d_sb;
+	struct erofs_sb_info *sbi = EROFS_SB(sb);
+	u64 id = huge_encode_dev(sb->s_bdev->bd_dev);
+
+	buf->f_type = sb->s_magic;
+	buf->f_bsize = EROFS_BLKSIZ;
+	buf->f_blocks = sbi->blocks;
+	buf->f_bfree = buf->f_bavail = 0;
+
+	buf->f_files = ULLONG_MAX;
+	buf->f_ffree = ULLONG_MAX - sbi->inos;
+
+	buf->f_namelen = EROFS_NAME_LEN;
+
+	buf->f_fsid.val[0] = (u32)id;
+	buf->f_fsid.val[1] = (u32)(id >> 32);
+	return 0;
+}
+
+static int erofs_show_options(struct seq_file *seq, struct dentry *root)
+{
+	struct erofs_sb_info *sbi __maybe_unused = EROFS_SB(root->d_sb);
+
+	if (test_opt(sbi, FAULT_INJECTION))
+		seq_printf(seq, ",fault_injection=%u",
+			   erofs_get_fault_rate(sbi));
+	return 0;
+}
+
+static int erofs_remount(struct super_block *sb, int *flags, char *data)
+{
+	struct erofs_sb_info *sbi = EROFS_SB(sb);
+	unsigned int org_mnt_opt = sbi->mount_opt;
+	unsigned int org_inject_rate = erofs_get_fault_rate(sbi);
+	int err;
+
+	DBG_BUGON(!sb_rdonly(sb));
+	err = parse_options(sb, data);
+	if (err)
+		goto out;
+
+	*flags |= SB_RDONLY;
+	return 0;
+out:
+	__erofs_build_fault_attr(sbi, org_inject_rate);
+	sbi->mount_opt = org_mnt_opt;
+
+	return err;
+}
+
+const struct super_operations erofs_sops = {
+	.alloc_inode = alloc_inode,
+	.free_inode = free_inode,
+	.statfs = erofs_statfs,
+	.show_options = erofs_show_options,
+	.remount_fs = erofs_remount,
+};
+
+module_init(erofs_module_init);
+module_exit(erofs_module_exit);
+
+MODULE_DESCRIPTION("Enhanced ROM File System");
+MODULE_AUTHOR("Gao Xiang, Chao Yu, Miao Xie, CONSUMER BG, HUAWEI Inc.");
+MODULE_LICENSE("GPL");
+
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v6 04/24] erofs: add raw address_space operations
  2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
                   ` (2 preceding siblings ...)
  2019-08-02 12:53 ` [PATCH v6 03/24] erofs: add super block operations Gao Xiang
@ 2019-08-02 12:53 ` Gao Xiang
  2019-08-29 10:17   ` Christoph Hellwig
  2019-08-02 12:53 ` [PATCH v6 05/24] erofs: add inode operations Gao Xiang
                   ` (20 subsequent siblings)
  24 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-08-02 12:53 UTC (permalink / raw)
  To: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds
  Cc: linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei, Gao Xiang

This commit adds functions for meta and raw data, and also
provides address_space_operations for raw data access.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/data.c | 423 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 423 insertions(+)
 create mode 100644 fs/erofs/data.c

diff --git a/fs/erofs/data.c b/fs/erofs/data.c
new file mode 100644
index 000000000000..9bb18fba773a
--- /dev/null
+++ b/fs/erofs/data.c
@@ -0,0 +1,423 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/fs/erofs/data.c
+ *
+ * Copyright (C) 2017-2018 HUAWEI, Inc.
+ *             http://www.huawei.com/
+ * Created by Gao Xiang <gaoxiang25@huawei.com>
+ */
+#include "internal.h"
+#include <linux/prefetch.h>
+
+#include <trace/events/erofs.h>
+
+static inline void read_endio(struct bio *bio)
+{
+	struct super_block *const sb = bio->bi_private;
+	struct bio_vec *bvec;
+	blk_status_t err = bio->bi_status;
+	struct bvec_iter_all iter_all;
+
+	if (time_to_inject(EROFS_SB(sb), FAULT_READ_IO)) {
+		erofs_show_injection_info(FAULT_READ_IO);
+		err = BLK_STS_IOERR;
+	}
+
+	bio_for_each_segment_all(bvec, bio, iter_all) {
+		struct page *page = bvec->bv_page;
+
+		/* page is already locked */
+		DBG_BUGON(PageUptodate(page));
+
+		if (unlikely(err))
+			SetPageError(page);
+		else
+			SetPageUptodate(page);
+
+		unlock_page(page);
+		/* page could be reclaimed now */
+	}
+	bio_put(bio);
+}
+
+/* prio -- true is used for dir */
+struct page *__erofs_get_meta_page(struct super_block *sb,
+				   erofs_blk_t blkaddr, bool prio, bool nofail)
+{
+	struct inode *const bd_inode = sb->s_bdev->bd_inode;
+	struct address_space *const mapping = bd_inode->i_mapping;
+	/* prefer retrying in the allocator to blindly looping below */
+	const gfp_t gfp = mapping_gfp_constraint(mapping, ~__GFP_FS) |
+		(nofail ? __GFP_NOFAIL : 0);
+	unsigned int io_retries = nofail ? EROFS_IO_MAX_RETRIES_NOFAIL : 0;
+	struct page *page;
+	int err;
+
+repeat:
+	page = find_or_create_page(mapping, blkaddr, gfp);
+	if (unlikely(!page)) {
+		DBG_BUGON(nofail);
+		return ERR_PTR(-ENOMEM);
+	}
+	DBG_BUGON(!PageLocked(page));
+
+	if (!PageUptodate(page)) {
+		struct bio *bio;
+
+		bio = erofs_grab_bio(sb, blkaddr, 1, sb, read_endio, nofail);
+		if (IS_ERR(bio)) {
+			DBG_BUGON(nofail);
+			err = PTR_ERR(bio);
+			goto err_out;
+		}
+
+		err = bio_add_page(bio, page, PAGE_SIZE, 0);
+		if (unlikely(err != PAGE_SIZE)) {
+			err = -EFAULT;
+			goto err_out;
+		}
+
+		__submit_bio(bio, REQ_OP_READ,
+			     REQ_META | (prio ? REQ_PRIO : 0));
+
+		lock_page(page);
+
+		/* this page has been truncated by others */
+		if (unlikely(page->mapping != mapping)) {
+unlock_repeat:
+			unlock_page(page);
+			put_page(page);
+			goto repeat;
+		}
+
+		/* more likely a read error */
+		if (unlikely(!PageUptodate(page))) {
+			if (io_retries) {
+				--io_retries;
+				goto unlock_repeat;
+			}
+			err = -EIO;
+			goto err_out;
+		}
+	}
+	return page;
+
+err_out:
+	unlock_page(page);
+	put_page(page);
+	return ERR_PTR(err);
+}
+
+static int erofs_map_blocks_flatmode(struct inode *inode,
+				     struct erofs_map_blocks *map,
+				     int flags)
+{
+	int err = 0;
+	erofs_blk_t nblocks, lastblk;
+	u64 offset = map->m_la;
+	struct erofs_vnode *vi = EROFS_V(inode);
+
+	trace_erofs_map_blocks_flatmode_enter(inode, map, flags);
+
+	nblocks = DIV_ROUND_UP(inode->i_size, PAGE_SIZE);
+	lastblk = nblocks - is_inode_flat_inline(inode);
+
+	if (unlikely(offset >= inode->i_size)) {
+		/* leave out-of-bound access unmapped */
+		map->m_flags = 0;
+		map->m_plen = 0;
+		goto out;
+	}
+
+	/* there is no hole in flatmode */
+	map->m_flags = EROFS_MAP_MAPPED;
+
+	if (offset < blknr_to_addr(lastblk)) {
+		map->m_pa = blknr_to_addr(vi->raw_blkaddr) + map->m_la;
+		map->m_plen = blknr_to_addr(lastblk) - offset;
+	} else if (is_inode_flat_inline(inode)) {
+		/* 2 - inode inline B: inode, [xattrs], inline last blk... */
+		struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
+
+		map->m_pa = iloc(sbi, vi->nid) + vi->inode_isize +
+			vi->xattr_isize + erofs_blkoff(map->m_la);
+		map->m_plen = inode->i_size - offset;
+
+		/* inline data should locate in one meta block */
+		if (erofs_blkoff(map->m_pa) + map->m_plen > PAGE_SIZE) {
+			DBG_BUGON(1);
+			err = -EIO;
+			goto err_out;
+		}
+
+		map->m_flags |= EROFS_MAP_META;
+	} else {
+		errln("internal error @ nid: %llu (size %llu), m_la 0x%llx",
+		      vi->nid, inode->i_size, map->m_la);
+		DBG_BUGON(1);
+		err = -EIO;
+		goto err_out;
+	}
+
+out:
+	map->m_llen = map->m_plen;
+
+err_out:
+	trace_erofs_map_blocks_flatmode_exit(inode, map, flags, 0);
+	return err;
+}
+
+int erofs_map_blocks(struct inode *inode,
+		     struct erofs_map_blocks *map, int flags)
+{
+	if (is_inode_layout_compression(inode))
+		return -ENOTSUPP;
+
+	return erofs_map_blocks_flatmode(inode, map, flags);
+}
+
+static inline struct bio *erofs_read_raw_page(struct bio *bio,
+					      struct address_space *mapping,
+					      struct page *page,
+					      erofs_off_t *last_block,
+					      unsigned int nblocks,
+					      bool ra)
+{
+	struct inode *const inode = mapping->host;
+	struct super_block *const sb = inode->i_sb;
+	erofs_off_t current_block = (erofs_off_t)page->index;
+	int err;
+
+	DBG_BUGON(!nblocks);
+
+	if (PageUptodate(page)) {
+		err = 0;
+		goto has_updated;
+	}
+
+	if (cleancache_get_page(page) == 0) {
+		err = 0;
+		SetPageUptodate(page);
+		goto has_updated;
+	}
+
+	/* note that for readpage case, bio also equals to NULL */
+	if (bio &&
+	    /* not continuous */
+	    *last_block + 1 != current_block) {
+submit_bio_retry:
+		__submit_bio(bio, REQ_OP_READ, 0);
+		bio = NULL;
+	}
+
+	if (!bio) {
+		struct erofs_map_blocks map = {
+			.m_la = blknr_to_addr(current_block),
+		};
+		erofs_blk_t blknr;
+		unsigned int blkoff;
+
+		err = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW);
+		if (unlikely(err))
+			goto err_out;
+
+		/* zero out the holed page */
+		if (unlikely(!(map.m_flags & EROFS_MAP_MAPPED))) {
+			zero_user_segment(page, 0, PAGE_SIZE);
+			SetPageUptodate(page);
+
+			/* imply err = 0, see erofs_map_blocks */
+			goto has_updated;
+		}
+
+		/* for RAW access mode, m_plen must be equal to m_llen */
+		DBG_BUGON(map.m_plen != map.m_llen);
+
+		blknr = erofs_blknr(map.m_pa);
+		blkoff = erofs_blkoff(map.m_pa);
+
+		/* deal with inline page */
+		if (map.m_flags & EROFS_MAP_META) {
+			void *vsrc, *vto;
+			struct page *ipage;
+
+			DBG_BUGON(map.m_plen > PAGE_SIZE);
+
+			ipage = erofs_get_meta_page(inode->i_sb, blknr, 0);
+
+			if (IS_ERR(ipage)) {
+				err = PTR_ERR(ipage);
+				goto err_out;
+			}
+
+			vsrc = kmap_atomic(ipage);
+			vto = kmap_atomic(page);
+			memcpy(vto, vsrc + blkoff, map.m_plen);
+			memset(vto + map.m_plen, 0, PAGE_SIZE - map.m_plen);
+			kunmap_atomic(vto);
+			kunmap_atomic(vsrc);
+			flush_dcache_page(page);
+
+			SetPageUptodate(page);
+			/* TODO: could we unlock the page earlier? */
+			unlock_page(ipage);
+			put_page(ipage);
+
+			/* imply err = 0, see erofs_map_blocks */
+			goto has_updated;
+		}
+
+		/* pa must be block-aligned for raw reading */
+		DBG_BUGON(erofs_blkoff(map.m_pa));
+
+		/* max # of continuous pages */
+		if (nblocks > DIV_ROUND_UP(map.m_plen, PAGE_SIZE))
+			nblocks = DIV_ROUND_UP(map.m_plen, PAGE_SIZE);
+		if (nblocks > BIO_MAX_PAGES)
+			nblocks = BIO_MAX_PAGES;
+
+		bio = erofs_grab_bio(sb, blknr, nblocks, sb,
+				     read_endio, false);
+		if (IS_ERR(bio)) {
+			err = PTR_ERR(bio);
+			bio = NULL;
+			goto err_out;
+		}
+	}
+
+	err = bio_add_page(bio, page, PAGE_SIZE, 0);
+	/* out of the extent or bio is full */
+	if (err < PAGE_SIZE)
+		goto submit_bio_retry;
+
+	*last_block = current_block;
+
+	/* shift in advance in case of it followed by too many gaps */
+	if (bio->bi_iter.bi_size >= bio->bi_max_vecs * PAGE_SIZE) {
+		/* err should reassign to 0 after submitting */
+		err = 0;
+		goto submit_bio_out;
+	}
+
+	return bio;
+
+err_out:
+	/* for sync reading, set page error immediately */
+	if (!ra) {
+		SetPageError(page);
+		ClearPageUptodate(page);
+	}
+has_updated:
+	unlock_page(page);
+
+	/* if updated manually, continuous pages has a gap */
+	if (bio)
+submit_bio_out:
+		__submit_bio(bio, REQ_OP_READ, 0);
+
+	return unlikely(err) ? ERR_PTR(err) : NULL;
+}
+
+/*
+ * since we dont have write or truncate flows, so no inode
+ * locking needs to be held at the moment.
+ */
+static int erofs_raw_access_readpage(struct file *file, struct page *page)
+{
+	erofs_off_t last_block;
+	struct bio *bio;
+
+	trace_erofs_readpage(page, true);
+
+	bio = erofs_read_raw_page(NULL, page->mapping,
+				  page, &last_block, 1, false);
+
+	if (IS_ERR(bio))
+		return PTR_ERR(bio);
+
+	DBG_BUGON(bio);	/* since we have only one bio -- must be NULL */
+	return 0;
+}
+
+static int erofs_raw_access_readpages(struct file *filp,
+				      struct address_space *mapping,
+				      struct list_head *pages,
+				      unsigned int nr_pages)
+{
+	erofs_off_t last_block;
+	struct bio *bio = NULL;
+	gfp_t gfp = readahead_gfp_mask(mapping);
+	struct page *page = list_last_entry(pages, struct page, lru);
+
+	trace_erofs_readpages(mapping->host, page, nr_pages, true);
+
+	for (; nr_pages; --nr_pages) {
+		page = list_entry(pages->prev, struct page, lru);
+
+		prefetchw(&page->flags);
+		list_del(&page->lru);
+
+		if (!add_to_page_cache_lru(page, mapping, page->index, gfp)) {
+			bio = erofs_read_raw_page(bio, mapping, page,
+						  &last_block, nr_pages, true);
+
+			/* all the page errors are ignored when readahead */
+			if (IS_ERR(bio)) {
+				pr_err("%s, readahead error at page %lu of nid %llu\n",
+				       __func__, page->index,
+				       EROFS_V(mapping->host)->nid);
+
+				bio = NULL;
+			}
+		}
+
+		/* pages could still be locked */
+		put_page(page);
+	}
+	DBG_BUGON(!list_empty(pages));
+
+	/* the rare case (end in gaps) */
+	if (unlikely(bio))
+		__submit_bio(bio, REQ_OP_READ, 0);
+	return 0;
+}
+
+static int erofs_get_block(struct inode *inode, sector_t iblock,
+			   struct buffer_head *bh, int create)
+{
+	struct erofs_map_blocks map = {
+		.m_la = iblock << 9,
+	};
+	int err;
+
+	err = erofs_map_blocks(inode, &map, EROFS_GET_BLOCKS_RAW);
+	if (err)
+		return err;
+
+	if (map.m_flags & EROFS_MAP_MAPPED)
+		bh->b_blocknr = erofs_blknr(map.m_pa);
+
+	return err;
+}
+
+static sector_t erofs_bmap(struct address_space *mapping, sector_t block)
+{
+	struct inode *inode = mapping->host;
+
+	if (is_inode_flat_inline(inode)) {
+		erofs_blk_t blks = i_size_read(inode) >> LOG_BLOCK_SIZE;
+
+		if (block >> LOG_SECTORS_PER_BLOCK >= blks)
+			return 0;
+	}
+
+	return generic_block_bmap(mapping, block, erofs_get_block);
+}
+
+/* for uncompressed (aligned) files and raw access for other files */
+const struct address_space_operations erofs_raw_access_aops = {
+	.readpage = erofs_raw_access_readpage,
+	.readpages = erofs_raw_access_readpages,
+	.bmap = erofs_bmap,
+};
+
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v6 05/24] erofs: add inode operations
  2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
                   ` (3 preceding siblings ...)
  2019-08-02 12:53 ` [PATCH v6 04/24] erofs: add raw address_space operations Gao Xiang
@ 2019-08-02 12:53 ` Gao Xiang
  2019-08-29 10:24   ` Christoph Hellwig
  2019-08-02 12:53 ` [PATCH v6 06/24] erofs: support special inode Gao Xiang
                   ` (19 subsequent siblings)
  24 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-08-02 12:53 UTC (permalink / raw)
  To: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds
  Cc: linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei, Gao Xiang

This adds core functions to get, read an inode.
It adds statx support as well.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/inode.c | 291 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 291 insertions(+)
 create mode 100644 fs/erofs/inode.c

diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
new file mode 100644
index 000000000000..b6ea997bc4ae
--- /dev/null
+++ b/fs/erofs/inode.c
@@ -0,0 +1,291 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/fs/erofs/inode.c
+ *
+ * Copyright (C) 2017-2018 HUAWEI, Inc.
+ *             http://www.huawei.com/
+ * Created by Gao Xiang <gaoxiang25@huawei.com>
+ */
+#include "internal.h"
+
+#include <trace/events/erofs.h>
+
+/* no locking */
+static int read_inode(struct inode *inode, void *data)
+{
+	struct erofs_vnode *vi = EROFS_V(inode);
+	struct erofs_inode_v1 *v1 = data;
+	const unsigned int advise = le16_to_cpu(v1->i_advise);
+	erofs_blk_t nblks = 0;
+
+	vi->datamode = __inode_data_mapping(advise);
+
+	if (unlikely(vi->datamode >= EROFS_INODE_LAYOUT_MAX)) {
+		errln("unsupported data mapping %u of nid %llu",
+		      vi->datamode, vi->nid);
+		DBG_BUGON(1);
+		return -EIO;
+	}
+
+	if (__inode_version(advise) == EROFS_INODE_LAYOUT_V2) {
+		struct erofs_inode_v2 *v2 = data;
+
+		vi->inode_isize = sizeof(struct erofs_inode_v2);
+		vi->xattr_isize = ondisk_xattr_ibody_size(v2->i_xattr_icount);
+
+		inode->i_mode = le16_to_cpu(v2->i_mode);
+		vi->raw_blkaddr = le32_to_cpu(v2->i_u.raw_blkaddr);
+
+		i_uid_write(inode, le32_to_cpu(v2->i_uid));
+		i_gid_write(inode, le32_to_cpu(v2->i_gid));
+		set_nlink(inode, le32_to_cpu(v2->i_nlink));
+
+		/* ns timestamp */
+		inode->i_mtime.tv_sec = inode->i_ctime.tv_sec =
+			le64_to_cpu(v2->i_ctime);
+		inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec =
+			le32_to_cpu(v2->i_ctime_nsec);
+
+		inode->i_size = le64_to_cpu(v2->i_size);
+
+		/* total blocks for compressed files */
+		if (is_inode_layout_compression(inode))
+			nblks = le32_to_cpu(v2->i_u.compressed_blocks);
+	} else if (__inode_version(advise) == EROFS_INODE_LAYOUT_V1) {
+		struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
+
+		vi->inode_isize = sizeof(struct erofs_inode_v1);
+		vi->xattr_isize = ondisk_xattr_ibody_size(v1->i_xattr_icount);
+
+		inode->i_mode = le16_to_cpu(v1->i_mode);
+		vi->raw_blkaddr = le32_to_cpu(v1->i_u.raw_blkaddr);
+
+		i_uid_write(inode, le16_to_cpu(v1->i_uid));
+		i_gid_write(inode, le16_to_cpu(v1->i_gid));
+		set_nlink(inode, le16_to_cpu(v1->i_nlink));
+
+		/* use build time to derive all file time */
+		inode->i_mtime.tv_sec = inode->i_ctime.tv_sec =
+			sbi->build_time;
+		inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec =
+			sbi->build_time_nsec;
+
+		inode->i_size = le32_to_cpu(v1->i_size);
+		if (is_inode_layout_compression(inode))
+			nblks = le32_to_cpu(v1->i_u.compressed_blocks);
+	} else {
+		errln("unsupported on-disk inode version %u of nid %llu",
+		      __inode_version(advise), vi->nid);
+		DBG_BUGON(1);
+		return -EIO;
+	}
+
+	if (!nblks)
+		/* measure inode.i_blocks as generic filesystems */
+		inode->i_blocks = roundup(inode->i_size, EROFS_BLKSIZ) >> 9;
+	else
+		inode->i_blocks = nblks << LOG_SECTORS_PER_BLOCK;
+	return 0;
+}
+
+/*
+ * try_lock can be required since locking order is:
+ *   file data(fs_inode)
+ *        meta(bd_inode)
+ * but the majority of the callers is "iget",
+ * in that case we are pretty sure no deadlock since
+ * no data operations exist. However I tend to
+ * try_lock since it takes no much overhead and
+ * will success immediately.
+ */
+static int fill_inline_data(struct inode *inode, void *data,
+			    unsigned int m_pofs)
+{
+	struct erofs_vnode *vi = EROFS_V(inode);
+	struct erofs_sb_info *sbi = EROFS_I_SB(inode);
+
+	/* should be inode inline C */
+	if (!is_inode_flat_inline(inode))
+		return 0;
+
+	/* fast symlink (following ext4) */
+	if (S_ISLNK(inode->i_mode) && inode->i_size < PAGE_SIZE) {
+		char *lnk = erofs_kmalloc(sbi, inode->i_size + 1, GFP_KERNEL);
+
+		if (unlikely(!lnk))
+			return -ENOMEM;
+
+		m_pofs += vi->inode_isize + vi->xattr_isize;
+
+		/* inline symlink data shouldn't across page boundary as well */
+		if (unlikely(m_pofs + inode->i_size > PAGE_SIZE)) {
+			DBG_BUGON(1);
+			kfree(lnk);
+			return -EIO;
+		}
+
+		/* get in-page inline data */
+		memcpy(lnk, data + m_pofs, inode->i_size);
+		lnk[inode->i_size] = '\0';
+
+		inode->i_link = lnk;
+		set_inode_fast_symlink(inode);
+	}
+	return 0;
+}
+
+static int fill_inode(struct inode *inode, int isdir)
+{
+	struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
+	struct erofs_vnode *vi = EROFS_V(inode);
+	struct page *page;
+	void *data;
+	int err;
+	erofs_blk_t blkaddr;
+	unsigned int ofs;
+
+	trace_erofs_fill_inode(inode, isdir);
+
+	blkaddr = erofs_blknr(iloc(sbi, vi->nid));
+	ofs = erofs_blkoff(iloc(sbi, vi->nid));
+
+	debugln("%s, reading inode nid %llu at %u of blkaddr %u",
+		__func__, vi->nid, ofs, blkaddr);
+
+	page = erofs_get_meta_page(inode->i_sb, blkaddr, isdir);
+
+	if (IS_ERR(page)) {
+		errln("failed to get inode (nid: %llu) page, err %ld",
+		      vi->nid, PTR_ERR(page));
+		return PTR_ERR(page);
+	}
+
+	DBG_BUGON(!PageUptodate(page));
+	data = page_address(page);
+
+	err = read_inode(inode, data + ofs);
+	if (!err) {
+		/* setup the new inode */
+		if (S_ISREG(inode->i_mode)) {
+			inode->i_op = &erofs_generic_iops;
+			inode->i_fop = &generic_ro_fops;
+		} else if (S_ISDIR(inode->i_mode)) {
+			inode->i_op = &erofs_dir_iops;
+			inode->i_fop = &erofs_dir_fops;
+		} else if (S_ISLNK(inode->i_mode)) {
+			/* by default, page_get_link is used for symlink */
+			inode->i_op = &erofs_symlink_iops;
+			inode_nohighmem(inode);
+		} else {
+			err = -EIO;
+			goto out_unlock;
+		}
+
+		if (is_inode_layout_compression(inode)) {
+			err = -ENOTSUPP;
+			goto out_unlock;
+		}
+
+		inode->i_mapping->a_ops = &erofs_raw_access_aops;
+
+		/* fill last page if inline data is available */
+		err = fill_inline_data(inode, data, ofs);
+	}
+
+out_unlock:
+	unlock_page(page);
+	put_page(page);
+	return err;
+}
+
+/*
+ * erofs nid is 64bits, but i_ino is 'unsigned long', therefore
+ * we should do more for 32-bit platform to find the right inode.
+ */
+#if BITS_PER_LONG == 32
+static int erofs_ilookup_test_actor(struct inode *inode, void *opaque)
+{
+	const erofs_nid_t nid = *(erofs_nid_t *)opaque;
+
+	return EROFS_V(inode)->nid == nid;
+}
+
+static int erofs_iget_set_actor(struct inode *inode, void *opaque)
+{
+	const erofs_nid_t nid = *(erofs_nid_t *)opaque;
+
+	inode->i_ino = erofs_inode_hash(nid);
+	return 0;
+}
+#endif
+
+static inline struct inode *erofs_iget_locked(struct super_block *sb,
+					      erofs_nid_t nid)
+{
+	const unsigned long hashval = erofs_inode_hash(nid);
+
+#if BITS_PER_LONG >= 64
+	/* it is safe to use iget_locked for >= 64-bit platform */
+	return iget_locked(sb, hashval);
+#else
+	return iget5_locked(sb, hashval, erofs_ilookup_test_actor,
+		erofs_iget_set_actor, &nid);
+#endif
+}
+
+struct inode *erofs_iget(struct super_block *sb,
+			 erofs_nid_t nid,
+			 bool isdir)
+{
+	struct inode *inode = erofs_iget_locked(sb, nid);
+
+	if (unlikely(!inode))
+		return ERR_PTR(-ENOMEM);
+
+	if (inode->i_state & I_NEW) {
+		int err;
+		struct erofs_vnode *vi = EROFS_V(inode);
+
+		vi->nid = nid;
+
+		err = fill_inode(inode, isdir);
+		if (likely(!err))
+			unlock_new_inode(inode);
+		else {
+			iget_failed(inode);
+			inode = ERR_PTR(err);
+		}
+	}
+	return inode;
+}
+
+int erofs_getattr(const struct path *path, struct kstat *stat,
+		  u32 request_mask, unsigned int query_flags)
+{
+	struct inode *const inode = d_inode(path->dentry);
+
+	if (is_inode_layout_compression(inode))
+		stat->attributes |= STATX_ATTR_COMPRESSED;
+
+	stat->attributes |= STATX_ATTR_IMMUTABLE;
+	stat->attributes_mask |= (STATX_ATTR_COMPRESSED |
+				  STATX_ATTR_IMMUTABLE);
+
+	generic_fillattr(inode, stat);
+	return 0;
+}
+
+const struct inode_operations erofs_generic_iops = {
+	.getattr = erofs_getattr,
+};
+
+const struct inode_operations erofs_symlink_iops = {
+	.get_link = page_get_link,
+	.getattr = erofs_getattr,
+};
+
+const struct inode_operations erofs_fast_symlink_iops = {
+	.get_link = simple_get_link,
+	.getattr = erofs_getattr,
+};
+
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v6 06/24] erofs: support special inode
  2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
                   ` (4 preceding siblings ...)
  2019-08-02 12:53 ` [PATCH v6 05/24] erofs: add inode operations Gao Xiang
@ 2019-08-02 12:53 ` Gao Xiang
  2019-08-29 10:25   ` Christoph Hellwig
  2019-08-02 12:53 ` [PATCH v6 07/24] erofs: add directory operations Gao Xiang
                   ` (18 subsequent siblings)
  24 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-08-02 12:53 UTC (permalink / raw)
  To: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds
  Cc: linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei, Gao Xiang

This patch adds to support special inode, such as
block dev, char, socket, pipe inode.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/inode.c | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index b6ea997bc4ae..637bf6e4de44 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -34,7 +34,16 @@ static int read_inode(struct inode *inode, void *data)
 		vi->xattr_isize = ondisk_xattr_ibody_size(v2->i_xattr_icount);
 
 		inode->i_mode = le16_to_cpu(v2->i_mode);
-		vi->raw_blkaddr = le32_to_cpu(v2->i_u.raw_blkaddr);
+		if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
+		    S_ISLNK(inode->i_mode))
+			vi->raw_blkaddr = le32_to_cpu(v2->i_u.raw_blkaddr);
+		else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
+			inode->i_rdev =
+				new_decode_dev(le32_to_cpu(v2->i_u.rdev));
+		else if (S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode))
+			inode->i_rdev = 0;
+		else
+			return -EIO;
 
 		i_uid_write(inode, le32_to_cpu(v2->i_uid));
 		i_gid_write(inode, le32_to_cpu(v2->i_gid));
@@ -58,7 +67,16 @@ static int read_inode(struct inode *inode, void *data)
 		vi->xattr_isize = ondisk_xattr_ibody_size(v1->i_xattr_icount);
 
 		inode->i_mode = le16_to_cpu(v1->i_mode);
-		vi->raw_blkaddr = le32_to_cpu(v1->i_u.raw_blkaddr);
+		if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
+		    S_ISLNK(inode->i_mode))
+			vi->raw_blkaddr = le32_to_cpu(v1->i_u.raw_blkaddr);
+		else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
+			inode->i_rdev =
+				new_decode_dev(le32_to_cpu(v1->i_u.rdev));
+		else if (S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode))
+			inode->i_rdev = 0;
+		else
+			return -EIO;
 
 		i_uid_write(inode, le16_to_cpu(v1->i_uid));
 		i_gid_write(inode, le16_to_cpu(v1->i_gid));
@@ -176,6 +194,11 @@ static int fill_inode(struct inode *inode, int isdir)
 			/* by default, page_get_link is used for symlink */
 			inode->i_op = &erofs_symlink_iops;
 			inode_nohighmem(inode);
+		} else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
+			S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
+			inode->i_op = &erofs_generic_iops;
+			init_special_inode(inode, inode->i_mode, inode->i_rdev);
+			goto out_unlock;
 		} else {
 			err = -EIO;
 			goto out_unlock;
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v6 07/24] erofs: add directory operations
  2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
                   ` (5 preceding siblings ...)
  2019-08-02 12:53 ` [PATCH v6 06/24] erofs: support special inode Gao Xiang
@ 2019-08-02 12:53 ` Gao Xiang
  2019-08-02 12:53 ` [PATCH v6 08/24] erofs: add namei functions Gao Xiang
                   ` (17 subsequent siblings)
  24 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-02 12:53 UTC (permalink / raw)
  To: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds
  Cc: linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei, Gao Xiang

This adds functions for directory, mainly readdir.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/dir.c | 147 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 147 insertions(+)
 create mode 100644 fs/erofs/dir.c

diff --git a/fs/erofs/dir.c b/fs/erofs/dir.c
new file mode 100644
index 000000000000..7cf7da8574c4
--- /dev/null
+++ b/fs/erofs/dir.c
@@ -0,0 +1,147 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/fs/erofs/dir.c
+ *
+ * Copyright (C) 2017-2018 HUAWEI, Inc.
+ *             http://www.huawei.com/
+ * Created by Gao Xiang <gaoxiang25@huawei.com>
+ */
+#include "internal.h"
+
+static const unsigned char erofs_filetype_table[EROFS_FT_MAX] = {
+	[EROFS_FT_UNKNOWN]	= DT_UNKNOWN,
+	[EROFS_FT_REG_FILE]	= DT_REG,
+	[EROFS_FT_DIR]		= DT_DIR,
+	[EROFS_FT_CHRDEV]	= DT_CHR,
+	[EROFS_FT_BLKDEV]	= DT_BLK,
+	[EROFS_FT_FIFO]		= DT_FIFO,
+	[EROFS_FT_SOCK]		= DT_SOCK,
+	[EROFS_FT_SYMLINK]	= DT_LNK,
+};
+
+static void debug_one_dentry(unsigned char d_type, const char *de_name,
+			     unsigned int de_namelen)
+{
+#ifdef CONFIG_EROFS_FS_DEBUG
+	/* since the on-disk name could not have the trailing '\0' */
+	unsigned char dbg_namebuf[EROFS_NAME_LEN + 1];
+
+	memcpy(dbg_namebuf, de_name, de_namelen);
+	dbg_namebuf[de_namelen] = '\0';
+
+	debugln("found dirent %s de_len %u d_type %d", dbg_namebuf,
+		de_namelen, d_type);
+#endif
+}
+
+static int erofs_fill_dentries(struct dir_context *ctx,
+			       void *dentry_blk, unsigned int *ofs,
+			       unsigned int nameoff, unsigned int maxsize)
+{
+	struct erofs_dirent *de = dentry_blk + *ofs;
+	const struct erofs_dirent *end = dentry_blk + nameoff;
+
+	while (de < end) {
+		const char *de_name;
+		unsigned int de_namelen;
+		unsigned char d_type;
+
+		if (de->file_type < EROFS_FT_MAX)
+			d_type = erofs_filetype_table[de->file_type];
+		else
+			d_type = DT_UNKNOWN;
+
+		nameoff = le16_to_cpu(de->nameoff);
+		de_name = (char *)dentry_blk + nameoff;
+
+		/* the last dirent in the block? */
+		if (de + 1 >= end)
+			de_namelen = strnlen(de_name, maxsize - nameoff);
+		else
+			de_namelen = le16_to_cpu(de[1].nameoff) - nameoff;
+
+		/* a corrupted entry is found */
+		if (unlikely(nameoff + de_namelen > maxsize ||
+			     de_namelen > EROFS_NAME_LEN)) {
+			DBG_BUGON(1);
+			return -EIO;
+		}
+
+		debug_one_dentry(d_type, de_name, de_namelen);
+		if (!dir_emit(ctx, de_name, de_namelen,
+			      le64_to_cpu(de->nid), d_type))
+			/* stopped by some reason */
+			return 1;
+		++de;
+		*ofs += sizeof(struct erofs_dirent);
+	}
+	*ofs = maxsize;
+	return 0;
+}
+
+static int erofs_readdir(struct file *f, struct dir_context *ctx)
+{
+	struct inode *dir = file_inode(f);
+	struct address_space *mapping = dir->i_mapping;
+	const size_t dirsize = i_size_read(dir);
+	unsigned int i = ctx->pos / EROFS_BLKSIZ;
+	unsigned int ofs = ctx->pos % EROFS_BLKSIZ;
+	int err = 0;
+	bool initial = true;
+
+	while (ctx->pos < dirsize) {
+		struct page *dentry_page;
+		struct erofs_dirent *de;
+		unsigned int nameoff, maxsize;
+
+		dentry_page = read_mapping_page(mapping, i, NULL);
+		if (IS_ERR(dentry_page))
+			continue;
+
+		de = (struct erofs_dirent *)kmap(dentry_page);
+
+		nameoff = le16_to_cpu(de->nameoff);
+
+		if (unlikely(nameoff < sizeof(struct erofs_dirent) ||
+			     nameoff >= PAGE_SIZE)) {
+			errln("%s, invalid de[0].nameoff %u",
+			      __func__, nameoff);
+
+			err = -EIO;
+			goto skip_this;
+		}
+
+		maxsize = min_t(unsigned int,
+				dirsize - ctx->pos + ofs, PAGE_SIZE);
+
+		/* search dirents at the arbitrary position */
+		if (unlikely(initial)) {
+			initial = false;
+
+			ofs = roundup(ofs, sizeof(struct erofs_dirent));
+			if (unlikely(ofs >= nameoff))
+				goto skip_this;
+		}
+
+		err = erofs_fill_dentries(ctx, de, &ofs, nameoff, maxsize);
+skip_this:
+		kunmap(dentry_page);
+
+		put_page(dentry_page);
+
+		ctx->pos = blknr_to_addr(i) + ofs;
+
+		if (unlikely(err))
+			break;
+		++i;
+		ofs = 0;
+	}
+	return err < 0 ? err : 0;
+}
+
+const struct file_operations erofs_dir_fops = {
+	.llseek		= generic_file_llseek,
+	.read		= generic_read_dir,
+	.iterate_shared	= erofs_readdir,
+};
+
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v6 08/24] erofs: add namei functions
  2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
                   ` (6 preceding siblings ...)
  2019-08-02 12:53 ` [PATCH v6 07/24] erofs: add directory operations Gao Xiang
@ 2019-08-02 12:53 ` Gao Xiang
  2019-08-29 10:28   ` Christoph Hellwig
  2019-08-02 12:53 ` [PATCH v6 09/24] erofs: support tracepoint Gao Xiang
                   ` (16 subsequent siblings)
  24 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-08-02 12:53 UTC (permalink / raw)
  To: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds
  Cc: linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei, Gao Xiang

This commit adds functions that transfer names to inodes.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/namei.c | 247 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 247 insertions(+)
 create mode 100644 fs/erofs/namei.c

diff --git a/fs/erofs/namei.c b/fs/erofs/namei.c
new file mode 100644
index 000000000000..73bf61637907
--- /dev/null
+++ b/fs/erofs/namei.c
@@ -0,0 +1,247 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/fs/erofs/namei.c
+ *
+ * Copyright (C) 2017-2018 HUAWEI, Inc.
+ *             http://www.huawei.com/
+ * Created by Gao Xiang <gaoxiang25@huawei.com>
+ */
+#include "internal.h"
+
+#include <trace/events/erofs.h>
+
+struct erofs_qstr {
+	const unsigned char *name;
+	const unsigned char *end;
+};
+
+/* based on the end of qn is accurate and it must have the trailing '\0' */
+static inline int dirnamecmp(const struct erofs_qstr *qn,
+			     const struct erofs_qstr *qd,
+			     unsigned int *matched)
+{
+	unsigned int i = *matched;
+
+	/*
+	 * on-disk error, let's only BUG_ON in the debugging mode.
+	 * otherwise, it will return 1 to just skip the invalid name
+	 * and go on (in consideration of the lookup performance).
+	 */
+	DBG_BUGON(qd->name > qd->end);
+
+	/* qd could not have trailing '\0' */
+	/* However it is absolutely safe if < qd->end */
+	while (qd->name + i < qd->end && qd->name[i] != '\0') {
+		if (qn->name[i] != qd->name[i]) {
+			*matched = i;
+			return qn->name[i] > qd->name[i] ? 1 : -1;
+		}
+		++i;
+	}
+	*matched = i;
+	/* See comments in __d_alloc on the terminating NUL character */
+	return qn->name[i] == '\0' ? 0 : 1;
+}
+
+#define nameoff_from_disk(off, sz)	(le16_to_cpu(off) & ((sz) - 1))
+
+static struct erofs_dirent *find_target_dirent(struct erofs_qstr *name,
+					       u8 *data,
+					       unsigned int dirblksize,
+					       const int ndirents)
+{
+	int head, back;
+	unsigned int startprfx, endprfx;
+	struct erofs_dirent *const de = (struct erofs_dirent *)data;
+
+	/* since the 1st dirent has been evaluated previously */
+	head = 1;
+	back = ndirents - 1;
+	startprfx = endprfx = 0;
+
+	while (head <= back) {
+		const int mid = head + (back - head) / 2;
+		const int nameoff = nameoff_from_disk(de[mid].nameoff,
+						      dirblksize);
+		unsigned int matched = min(startprfx, endprfx);
+		struct erofs_qstr dname = {
+			.name = data + nameoff,
+			.end = unlikely(mid >= ndirents - 1) ?
+				data + dirblksize :
+				data + nameoff_from_disk(de[mid + 1].nameoff,
+							 dirblksize)
+		};
+
+		/* string comparison without already matched prefix */
+		int ret = dirnamecmp(name, &dname, &matched);
+
+		if (unlikely(!ret)) {
+			return de + mid;
+		} else if (ret > 0) {
+			head = mid + 1;
+			startprfx = matched;
+		} else {
+			back = mid - 1;
+			endprfx = matched;
+		}
+	}
+
+	return ERR_PTR(-ENOENT);
+}
+
+static struct page *find_target_block_classic(struct inode *dir,
+					      struct erofs_qstr *name,
+					      int *_ndirents)
+{
+	unsigned int startprfx, endprfx;
+	int head, back;
+	struct address_space *const mapping = dir->i_mapping;
+	struct page *candidate = ERR_PTR(-ENOENT);
+
+	startprfx = endprfx = 0;
+	head = 0;
+	back = inode_datablocks(dir) - 1;
+
+	while (head <= back) {
+		const int mid = head + (back - head) / 2;
+		struct page *page = read_mapping_page(mapping, mid, NULL);
+
+		if (!IS_ERR(page)) {
+			struct erofs_dirent *de = kmap_atomic(page);
+			const int nameoff = nameoff_from_disk(de->nameoff,
+							      EROFS_BLKSIZ);
+			const int ndirents = nameoff / sizeof(*de);
+			int diff;
+			unsigned int matched;
+			struct erofs_qstr dname;
+
+			if (unlikely(!ndirents)) {
+				DBG_BUGON(1);
+				kunmap_atomic(de);
+				put_page(page);
+				page = ERR_PTR(-EIO);
+				goto out;
+			}
+
+			matched = min(startprfx, endprfx);
+
+			dname.name = (u8 *)de + nameoff;
+			if (ndirents == 1)
+				dname.end = (u8 *)de + EROFS_BLKSIZ;
+			else
+				dname.end = (u8 *)de +
+					nameoff_from_disk(de[1].nameoff,
+							  EROFS_BLKSIZ);
+
+			/* string comparison without already matched prefix */
+			diff = dirnamecmp(name, &dname, &matched);
+			kunmap_atomic(de);
+
+			if (unlikely(!diff)) {
+				*_ndirents = 0;
+				goto out;
+			} else if (diff > 0) {
+				head = mid + 1;
+				startprfx = matched;
+
+				if (!IS_ERR(candidate))
+					put_page(candidate);
+				candidate = page;
+				*_ndirents = ndirents;
+			} else {
+				put_page(page);
+
+				back = mid - 1;
+				endprfx = matched;
+			}
+			continue;
+		}
+out:		/* free if the candidate is valid */
+		if (!IS_ERR(candidate))
+			put_page(candidate);
+		return page;
+	}
+	return candidate;
+}
+
+int erofs_namei(struct inode *dir,
+		struct qstr *name,
+		erofs_nid_t *nid, unsigned int *d_type)
+{
+	int ndirents;
+	struct page *page;
+	void *data;
+	struct erofs_dirent *de;
+	struct erofs_qstr qn;
+
+	if (unlikely(!dir->i_size))
+		return -ENOENT;
+
+	qn.name = name->name;
+	qn.end = name->name + name->len;
+
+	ndirents = 0;
+	page = find_target_block_classic(dir, &qn, &ndirents);
+
+	if (IS_ERR(page))
+		return PTR_ERR(page);
+
+	data = kmap_atomic(page);
+	/* the target page has been mapped */
+	if (ndirents)
+		de = find_target_dirent(&qn, data, EROFS_BLKSIZ, ndirents);
+	else
+		de = (struct erofs_dirent *)data;
+
+	if (!IS_ERR(de)) {
+		*nid = le64_to_cpu(de->nid);
+		*d_type = de->file_type;
+	}
+
+	kunmap_atomic(data);
+	put_page(page);
+
+	return PTR_ERR_OR_ZERO(de);
+}
+
+/* NOTE: i_mutex is already held by vfs */
+static struct dentry *erofs_lookup(struct inode *dir,
+				   struct dentry *dentry,
+				   unsigned int flags)
+{
+	int err;
+	erofs_nid_t nid;
+	unsigned int d_type;
+	struct inode *inode;
+
+	DBG_BUGON(!d_really_is_negative(dentry));
+	/* dentry must be unhashed in lookup, no need to worry about */
+	DBG_BUGON(!d_unhashed(dentry));
+
+	trace_erofs_lookup(dir, dentry, flags);
+
+	/* file name exceeds fs limit */
+	if (unlikely(dentry->d_name.len > EROFS_NAME_LEN))
+		return ERR_PTR(-ENAMETOOLONG);
+
+	/* false uninitialized warnings on gcc 4.8.x */
+	err = erofs_namei(dir, &dentry->d_name, &nid, &d_type);
+
+	if (err == -ENOENT) {
+		/* negative dentry */
+		inode = NULL;
+	} else if (unlikely(err)) {
+		inode = ERR_PTR(err);
+	} else {
+		debugln("%s, %s (nid %llu) found, d_type %u", __func__,
+			dentry->d_name.name, nid, d_type);
+		inode = erofs_iget(dir->i_sb, nid, d_type == EROFS_FT_DIR);
+	}
+	return d_splice_alias(inode, dentry);
+}
+
+const struct inode_operations erofs_dir_iops = {
+	.lookup = erofs_lookup,
+	.getattr = erofs_getattr,
+};
+
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v6 09/24] erofs: support tracepoint
  2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
                   ` (7 preceding siblings ...)
  2019-08-02 12:53 ` [PATCH v6 08/24] erofs: add namei functions Gao Xiang
@ 2019-08-02 12:53 ` Gao Xiang
  2019-08-02 12:53 ` [PATCH v6 10/24] erofs: update Kconfig and Makefile Gao Xiang
                   ` (15 subsequent siblings)
  24 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-02 12:53 UTC (permalink / raw)
  To: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds
  Cc: linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei, Gao Xiang

Add basic tracepoints for ->readpage{,s}, ->lookup,
->destroy_inode, fill_inode and map_blocks.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 include/trace/events/erofs.h | 241 +++++++++++++++++++++++++++++++++++
 1 file changed, 241 insertions(+)
 create mode 100644 include/trace/events/erofs.h

diff --git a/include/trace/events/erofs.h b/include/trace/events/erofs.h
new file mode 100644
index 000000000000..0c5847c54b60
--- /dev/null
+++ b/include/trace/events/erofs.h
@@ -0,0 +1,241 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM erofs
+
+#if !defined(_TRACE_EROFS_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_EROFS_H
+
+#include <linux/tracepoint.h>
+
+#define show_dev(dev)		MAJOR(dev), MINOR(dev)
+#define show_dev_nid(entry)	show_dev(entry->dev), entry->nid
+
+#define show_file_type(type)						\
+	__print_symbolic(type,						\
+		{ 0,		"FILE" },				\
+		{ 1,		"DIR" })
+
+#define show_map_flags(flags) __print_flags(flags, "|",	\
+	{ EROFS_GET_BLOCKS_RAW,	"RAW" })
+
+#define show_mflags(flags) __print_flags(flags, "",	\
+	{ EROFS_MAP_MAPPED,	"M" },			\
+	{ EROFS_MAP_META,	"I" })
+
+TRACE_EVENT(erofs_lookup,
+
+	TP_PROTO(struct inode *dir, struct dentry *dentry, unsigned int flags),
+
+	TP_ARGS(dir, dentry, flags),
+
+	TP_STRUCT__entry(
+		__field(dev_t,		dev	)
+		__field(erofs_nid_t,	nid	)
+		__field(const char *,	name	)
+		__field(unsigned int,	flags	)
+	),
+
+	TP_fast_assign(
+		__entry->dev	= dir->i_sb->s_dev;
+		__entry->nid	= EROFS_V(dir)->nid;
+		__entry->name	= dentry->d_name.name;
+		__entry->flags	= flags;
+	),
+
+	TP_printk("dev = (%d,%d), pnid = %llu, name:%s, flags:%x",
+		show_dev_nid(__entry),
+		__entry->name,
+		__entry->flags)
+);
+
+TRACE_EVENT(erofs_fill_inode,
+	TP_PROTO(struct inode *inode, int isdir),
+	TP_ARGS(inode, isdir),
+
+	TP_STRUCT__entry(
+		__field(dev_t,		dev	)
+		__field(erofs_nid_t,	nid	)
+		__field(erofs_blk_t,	blkaddr )
+		__field(unsigned int,	ofs	)
+		__field(int,		isdir	)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= inode->i_sb->s_dev;
+		__entry->nid		= EROFS_V(inode)->nid;
+		__entry->blkaddr	= erofs_blknr(iloc(EROFS_I_SB(inode), __entry->nid));
+		__entry->ofs		= erofs_blkoff(iloc(EROFS_I_SB(inode), __entry->nid));
+		__entry->isdir		= isdir;
+	),
+
+	TP_printk("dev = (%d,%d), nid = %llu, blkaddr %u ofs %u, isdir %d",
+		  show_dev_nid(__entry),
+		  __entry->blkaddr, __entry->ofs,
+		  __entry->isdir)
+);
+
+TRACE_EVENT(erofs_readpage,
+
+	TP_PROTO(struct page *page, bool raw),
+
+	TP_ARGS(page, raw),
+
+	TP_STRUCT__entry(
+		__field(dev_t,		dev	)
+		__field(erofs_nid_t,    nid     )
+		__field(int,		dir	)
+		__field(pgoff_t,	index	)
+		__field(int,		uptodate)
+		__field(bool,		raw	)
+	),
+
+	TP_fast_assign(
+		__entry->dev	= page->mapping->host->i_sb->s_dev;
+		__entry->nid	= EROFS_V(page->mapping->host)->nid;
+		__entry->dir	= S_ISDIR(page->mapping->host->i_mode);
+		__entry->index	= page->index;
+		__entry->uptodate = PageUptodate(page);
+		__entry->raw = raw;
+	),
+
+	TP_printk("dev = (%d,%d), nid = %llu, %s, index = %lu, uptodate = %d "
+		"raw = %d",
+		show_dev_nid(__entry),
+		show_file_type(__entry->dir),
+		(unsigned long)__entry->index,
+		__entry->uptodate,
+		__entry->raw)
+);
+
+TRACE_EVENT(erofs_readpages,
+
+	TP_PROTO(struct inode *inode, struct page *page, unsigned int nrpage,
+		bool raw),
+
+	TP_ARGS(inode, page, nrpage, raw),
+
+	TP_STRUCT__entry(
+		__field(dev_t,		dev	)
+		__field(erofs_nid_t,	nid	)
+		__field(pgoff_t,	start	)
+		__field(unsigned int,	nrpage	)
+		__field(bool,		raw	)
+	),
+
+	TP_fast_assign(
+		__entry->dev	= inode->i_sb->s_dev;
+		__entry->nid	= EROFS_V(inode)->nid;
+		__entry->start	= page->index;
+		__entry->nrpage	= nrpage;
+		__entry->raw	= raw;
+	),
+
+	TP_printk("dev = (%d,%d), nid = %llu, start = %lu nrpage = %u raw = %d",
+		show_dev_nid(__entry),
+		(unsigned long)__entry->start,
+		__entry->nrpage,
+		__entry->raw)
+);
+
+DECLARE_EVENT_CLASS(erofs__map_blocks_enter,
+	TP_PROTO(struct inode *inode, struct erofs_map_blocks *map,
+		 unsigned int flags),
+
+	TP_ARGS(inode, map, flags),
+
+	TP_STRUCT__entry(
+		__field(	dev_t,		dev		)
+		__field(	erofs_nid_t,	nid		)
+		__field(	erofs_off_t,	la		)
+		__field(	u64,		llen		)
+		__field(	unsigned int,	flags		)
+	),
+
+	TP_fast_assign(
+		__entry->dev    = inode->i_sb->s_dev;
+		__entry->nid    = EROFS_V(inode)->nid;
+		__entry->la	= map->m_la;
+		__entry->llen	= map->m_llen;
+		__entry->flags	= flags;
+	),
+
+	TP_printk("dev = (%d,%d), nid = %llu, la %llu llen %llu flags %s",
+		  show_dev_nid(__entry),
+		  __entry->la, __entry->llen,
+		  __entry->flags ? show_map_flags(__entry->flags) : "NULL")
+);
+
+DEFINE_EVENT(erofs__map_blocks_enter, erofs_map_blocks_flatmode_enter,
+	TP_PROTO(struct inode *inode, struct erofs_map_blocks *map,
+		 unsigned flags),
+
+	TP_ARGS(inode, map, flags)
+);
+
+DECLARE_EVENT_CLASS(erofs__map_blocks_exit,
+	TP_PROTO(struct inode *inode, struct erofs_map_blocks *map,
+		 unsigned int flags, int ret),
+
+	TP_ARGS(inode, map, flags, ret),
+
+	TP_STRUCT__entry(
+		__field(	dev_t,		dev		)
+		__field(	erofs_nid_t,	nid		)
+		__field(        unsigned int,   flags           )
+		__field(	erofs_off_t,	la		)
+		__field(	erofs_off_t,	pa		)
+		__field(	u64,		llen		)
+		__field(	u64,		plen		)
+		__field(        unsigned int,	mflags		)
+		__field(	int,		ret		)
+	),
+
+	TP_fast_assign(
+		__entry->dev    = inode->i_sb->s_dev;
+		__entry->nid    = EROFS_V(inode)->nid;
+		__entry->flags	= flags;
+		__entry->la	= map->m_la;
+		__entry->pa	= map->m_pa;
+		__entry->llen	= map->m_llen;
+		__entry->plen	= map->m_plen;
+		__entry->mflags	= map->m_flags;
+		__entry->ret	= ret;
+	),
+
+	TP_printk("dev = (%d,%d), nid = %llu, flags %s "
+		  "la %llu pa %llu llen %llu plen %llu mflags %s ret %d",
+		  show_dev_nid(__entry),
+		  __entry->flags ? show_map_flags(__entry->flags) : "NULL",
+		  __entry->la, __entry->pa, __entry->llen, __entry->plen,
+		  show_mflags(__entry->mflags), __entry->ret)
+);
+
+DEFINE_EVENT(erofs__map_blocks_exit, erofs_map_blocks_flatmode_exit,
+	TP_PROTO(struct inode *inode, struct erofs_map_blocks *map,
+		 unsigned flags, int ret),
+
+	TP_ARGS(inode, map, flags, ret)
+);
+
+TRACE_EVENT(erofs_destroy_inode,
+	TP_PROTO(struct inode *inode),
+
+	TP_ARGS(inode),
+
+	TP_STRUCT__entry(
+		__field(	dev_t,		dev		)
+		__field(	erofs_nid_t,	nid		)
+	),
+
+	TP_fast_assign(
+		__entry->dev	= inode->i_sb->s_dev;
+		__entry->nid	= EROFS_V(inode)->nid;
+	),
+
+	TP_printk("dev = (%d,%d), nid = %llu", show_dev_nid(__entry))
+);
+
+#endif /* _TRACE_EROFS_H */
+
+ /* This part must be outside protection */
+#include <trace/define_trace.h>
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v6 10/24] erofs: update Kconfig and Makefile
  2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
                   ` (8 preceding siblings ...)
  2019-08-02 12:53 ` [PATCH v6 09/24] erofs: support tracepoint Gao Xiang
@ 2019-08-02 12:53 ` Gao Xiang
  2019-08-02 12:53 ` [PATCH v6 11/24] erofs: introduce xattr & posixacl support Gao Xiang
                   ` (14 subsequent siblings)
  24 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-02 12:53 UTC (permalink / raw)
  To: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds
  Cc: linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei, Gao Xiang

This commit adds Makefile and Kconfig for erofs, and
updates Makefile and Kconfig files in the fs directory.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/Kconfig        |  1 +
 fs/Makefile       |  1 +
 fs/erofs/Kconfig  | 36 ++++++++++++++++++++++++++++++++++++
 fs/erofs/Makefile |  9 +++++++++
 4 files changed, 47 insertions(+)
 create mode 100644 fs/erofs/Kconfig
 create mode 100644 fs/erofs/Makefile

diff --git a/fs/Kconfig b/fs/Kconfig
index bfb1c6095c7a..669d46550e6d 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -261,6 +261,7 @@ source "fs/romfs/Kconfig"
 source "fs/pstore/Kconfig"
 source "fs/sysv/Kconfig"
 source "fs/ufs/Kconfig"
+source "fs/erofs/Kconfig"
 
 endif # MISC_FILESYSTEMS
 
diff --git a/fs/Makefile b/fs/Makefile
index d60089fd689b..b2e4973a0bea 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -130,3 +130,4 @@ obj-$(CONFIG_F2FS_FS)		+= f2fs/
 obj-$(CONFIG_CEPH_FS)		+= ceph/
 obj-$(CONFIG_PSTORE)		+= pstore/
 obj-$(CONFIG_EFIVAR_FS)		+= efivarfs/
+obj-$(CONFIG_EROFS_FS)		+= erofs/
diff --git a/fs/erofs/Kconfig b/fs/erofs/Kconfig
new file mode 100644
index 000000000000..98f05043448a
--- /dev/null
+++ b/fs/erofs/Kconfig
@@ -0,0 +1,36 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+config EROFS_FS
+	tristate "EROFS filesystem support"
+	depends on BLOCK
+	help
+	  EROFS (Enhanced Read-Only File System) is a lightweight
+	  read-only file system with modern designs (eg. page-sized
+	  blocks, inline xattrs/data, etc.) for scenarios which need
+	  high-performance read-only requirements, e.g. Android OS
+	  for mobile phones and LIVECDs.
+
+	  It also provides fixed-sized output compression support,
+	  which improves storage density, keeps relatively higher
+	  compression ratios, which is more useful to achieve high
+	  performance for embedded devices with limited memory.
+
+	  If unsure, say N.
+
+config EROFS_FS_DEBUG
+	bool "EROFS debugging feature"
+	depends on EROFS_FS
+	help
+	  Print debugging messages and enable more BUG_ONs which check
+	  filesystem consistency and find potential issues aggressively,
+	  which can be used for Android eng build, for example.
+
+	  For daily use, say N.
+
+config EROFS_FAULT_INJECTION
+	bool "EROFS fault injection facility"
+	depends on EROFS_FS
+	help
+	  Test EROFS to inject faults such as ENOMEM, EIO, and so on.
+	  If unsure, say N.
+
diff --git a/fs/erofs/Makefile b/fs/erofs/Makefile
new file mode 100644
index 000000000000..c3f4e549ef90
--- /dev/null
+++ b/fs/erofs/Makefile
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+EROFS_VERSION = "1.0"
+
+ccflags-y += -DEROFS_VERSION=\"$(EROFS_VERSION)\"
+
+obj-$(CONFIG_EROFS_FS) += erofs.o
+erofs-objs := super.o inode.o data.o namei.o dir.o
+
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v6 11/24] erofs: introduce xattr & posixacl support
  2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
                   ` (9 preceding siblings ...)
  2019-08-02 12:53 ` [PATCH v6 10/24] erofs: update Kconfig and Makefile Gao Xiang
@ 2019-08-02 12:53 ` Gao Xiang
  2019-08-02 12:53 ` [PATCH v6 12/24] erofs: introduce tagged pointer Gao Xiang
                   ` (13 subsequent siblings)
  24 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-02 12:53 UTC (permalink / raw)
  To: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds
  Cc: linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei, Gao Xiang

This implements xattr and posixacl functionalities.

1) Inline and shared xattrs are introduced for flexibility.

   Specifically, if the same xattr is used for a large number of
   inodes or the size of a xattr is so large that unsuitable to
   inline, a shared xattr will be used instead in xattr meta.

2) Add .get_acl() to read the file's acl from its xattrs to
   make POSIX ACL usable.

   Here is the on-disk detail,
   fullname: system.posix_acl_access
   struct erofs_xattr_entry:
           .e_name_len = 0
           .e_name_index = EROFS_XATTR_INDEX_POSIX_ACL_ACCESS (2)

   fullname: system.posix_acl_default
   struct erofs_xattr_entry:
           .e_name_len = 0
           .e_name_index = EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT (3)

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/Kconfig    |  38 +++
 fs/erofs/Makefile   |   1 +
 fs/erofs/inode.c    |  14 +-
 fs/erofs/internal.h |  16 +
 fs/erofs/namei.c    |   6 +-
 fs/erofs/super.c    |  77 ++++-
 fs/erofs/xattr.c    | 700 ++++++++++++++++++++++++++++++++++++++++++++
 fs/erofs/xattr.h    |  94 ++++++
 8 files changed, 943 insertions(+), 3 deletions(-)
 create mode 100644 fs/erofs/xattr.c
 create mode 100644 fs/erofs/xattr.h

diff --git a/fs/erofs/Kconfig b/fs/erofs/Kconfig
index 98f05043448a..c5e7c5ae026e 100644
--- a/fs/erofs/Kconfig
+++ b/fs/erofs/Kconfig
@@ -34,3 +34,41 @@ config EROFS_FAULT_INJECTION
 	  Test EROFS to inject faults such as ENOMEM, EIO, and so on.
 	  If unsure, say N.
 
+config EROFS_FS_XATTR
+	bool "EROFS extended attributes"
+	depends on EROFS_FS
+	default y
+	help
+	  Extended attributes are name:value pairs associated with inodes by
+	  the kernel or by users (see the attr(5) manual page, or visit
+	  <http://acl.bestbits.at/> for details).
+
+	  If unsure, say N.
+
+config EROFS_FS_POSIX_ACL
+	bool "EROFS Access Control Lists"
+	depends on EROFS_FS_XATTR
+	select FS_POSIX_ACL
+	default y
+	help
+	  Posix Access Control Lists (ACLs) support permissions for users and
+	  groups beyond the owner/group/world scheme.
+
+	  To learn more about Access Control Lists, visit the POSIX ACLs for
+	  Linux website <http://acl.bestbits.at/>.
+
+	  If you don't know what Access Control Lists are, say N.
+
+config EROFS_FS_SECURITY
+	bool "EROFS Security Labels"
+	depends on EROFS_FS_XATTR
+	default y
+	help
+	  Security labels provide an access control facility to support Linux
+	  Security Models (LSMs) accepted by AppArmor, SELinux, Smack and TOMOYO
+	  Linux. This option enables an extended attribute handler for file
+	  security labels in the erofs filesystem, so that it requires enabling
+	  the extended attribute support in advance.
+
+	  If you are not using a security module, say N.
+
diff --git a/fs/erofs/Makefile b/fs/erofs/Makefile
index c3f4e549ef90..190a73083f23 100644
--- a/fs/erofs/Makefile
+++ b/fs/erofs/Makefile
@@ -6,4 +6,5 @@ ccflags-y += -DEROFS_VERSION=\"$(EROFS_VERSION)\"
 
 obj-$(CONFIG_EROFS_FS) += erofs.o
 erofs-objs := super.o inode.o data.o namei.o dir.o
+erofs-$(CONFIG_EROFS_FS_XATTR) += xattr.o
 
diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index 637bf6e4de44..aee53988aef5 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -6,7 +6,7 @@
  *             http://www.huawei.com/
  * Created by Gao Xiang <gaoxiang25@huawei.com>
  */
-#include "internal.h"
+#include "xattr.h"
 
 #include <trace/events/erofs.h>
 
@@ -300,15 +300,27 @@ int erofs_getattr(const struct path *path, struct kstat *stat,
 
 const struct inode_operations erofs_generic_iops = {
 	.getattr = erofs_getattr,
+#ifdef CONFIG_EROFS_FS_XATTR
+	.listxattr = erofs_listxattr,
+#endif
+	.get_acl = erofs_get_acl,
 };
 
 const struct inode_operations erofs_symlink_iops = {
 	.get_link = page_get_link,
 	.getattr = erofs_getattr,
+#ifdef CONFIG_EROFS_FS_XATTR
+	.listxattr = erofs_listxattr,
+#endif
+	.get_acl = erofs_get_acl,
 };
 
 const struct inode_operations erofs_fast_symlink_iops = {
 	.get_link = simple_get_link,
 	.getattr = erofs_getattr,
+#ifdef CONFIG_EROFS_FS_XATTR
+	.listxattr = erofs_listxattr,
+#endif
+	.get_acl = erofs_get_acl,
 };
 
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 2c94149d7218..004d5dbf2e7a 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -63,6 +63,9 @@ typedef u32 erofs_blk_t;
 struct erofs_sb_info {
 	u32 blocks;
 	u32 meta_blkaddr;
+#ifdef CONFIG_EROFS_FS_XATTR
+	u32 xattr_blkaddr;
+#endif
 
 	/* inode slot unit size in bit shift */
 	unsigned char islotbits;
@@ -133,6 +136,8 @@ static inline void *erofs_kmalloc(struct erofs_sb_info *sbi,
 #define EROFS_I_SB(inode) ((struct erofs_sb_info *)(inode)->i_sb->s_fs_info)
 
 /* Mount flags set via mount options or defaults */
+#define EROFS_MOUNT_XATTR_USER		0x00000010
+#define EROFS_MOUNT_POSIX_ACL		0x00000020
 #define EROFS_MOUNT_FAULT_INJECTION	0x00000040
 
 #define clear_opt(sbi, option)	((sbi)->mount_opt &= ~EROFS_MOUNT_##option)
@@ -167,13 +172,24 @@ static inline erofs_off_t iloc(struct erofs_sb_info *sbi, erofs_nid_t nid)
 	return blknr_to_addr(sbi->meta_blkaddr) + (nid << sbi->islotbits);
 }
 
+/* atomic flag definitions */
+#define EROFS_V_EA_INITED_BIT	0
+
+/* bitlock definitions (arranged in reverse order) */
+#define EROFS_V_BL_XATTR_BIT	(BITS_PER_LONG - 1)
 struct erofs_vnode {
 	erofs_nid_t nid;
 
+	/* atomic flags (including bitlocks) */
+	unsigned long flags;
+
 	unsigned char datamode;
 	unsigned char inode_isize;
 	unsigned short xattr_isize;
 
+	unsigned int xattr_shared_count;
+	unsigned int *xattr_shared_xattrs;
+
 	erofs_blk_t raw_blkaddr;
 	/* the corresponding vfs inode */
 	struct inode vfs_inode;
diff --git a/fs/erofs/namei.c b/fs/erofs/namei.c
index 73bf61637907..ccce53d46547 100644
--- a/fs/erofs/namei.c
+++ b/fs/erofs/namei.c
@@ -6,7 +6,7 @@
  *             http://www.huawei.com/
  * Created by Gao Xiang <gaoxiang25@huawei.com>
  */
-#include "internal.h"
+#include "xattr.h"
 
 #include <trace/events/erofs.h>
 
@@ -243,5 +243,9 @@ static struct dentry *erofs_lookup(struct inode *dir,
 const struct inode_operations erofs_dir_iops = {
 	.lookup = erofs_lookup,
 	.getattr = erofs_getattr,
+#ifdef CONFIG_EROFS_FS_XATTR
+	.listxattr = erofs_listxattr,
+#endif
+	.get_acl = erofs_get_acl,
 };
 
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index cd4bd6f48173..561ae6f7fe13 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -11,7 +11,7 @@
 #include <linux/statfs.h>
 #include <linux/parser.h>
 #include <linux/seq_file.h>
-#include "internal.h"
+#include "xattr.h"
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/erofs.h>
@@ -61,6 +61,8 @@ static void free_inode(struct inode *inode)
 	if (is_inode_fast_symlink(inode))
 		kfree(inode->i_link);
 
+	kfree(vi->xattr_shared_xattrs);
+
 	kmem_cache_free(erofs_inode_cachep, vi);
 }
 
@@ -118,6 +120,9 @@ static int superblock_read(struct super_block *sb)
 
 	sbi->blocks = le32_to_cpu(layout->blocks);
 	sbi->meta_blkaddr = le32_to_cpu(layout->meta_blkaddr);
+#ifdef CONFIG_EROFS_FS_XATTR
+	sbi->xattr_blkaddr = le32_to_cpu(layout->xattr_blkaddr);
+#endif
 	sbi->islotbits = ffs(sizeof(struct erofs_inode_v1)) - 1;
 	sbi->root_nid = le16_to_cpu(layout->root_nid);
 	sbi->inos = le64_to_cpu(layout->inos);
@@ -195,14 +200,28 @@ static unsigned int erofs_get_fault_rate(struct erofs_sb_info *sbi)
 /* set up default EROFS parameters */
 static void default_options(struct erofs_sb_info *sbi)
 {
+#ifdef CONFIG_EROFS_FS_XATTR
+	set_opt(sbi, XATTR_USER);
+#endif
+#ifdef CONFIG_EROFS_FS_POSIX_ACL
+	set_opt(sbi, POSIX_ACL);
+#endif
 }
 
 enum {
+	Opt_user_xattr,
+	Opt_nouser_xattr,
+	Opt_acl,
+	Opt_noacl,
 	Opt_fault_injection,
 	Opt_err
 };
 
 static match_table_t erofs_tokens = {
+	{Opt_user_xattr, "user_xattr"},
+	{Opt_nouser_xattr, "nouser_xattr"},
+	{Opt_acl, "acl"},
+	{Opt_noacl, "noacl"},
 	{Opt_fault_injection, "fault_injection=%u"},
 	{Opt_err, NULL}
 };
@@ -226,6 +245,36 @@ static int parse_options(struct super_block *sb, char *options)
 		token = match_token(p, erofs_tokens, args);
 
 		switch (token) {
+#ifdef CONFIG_EROFS_FS_XATTR
+		case Opt_user_xattr:
+			set_opt(EROFS_SB(sb), XATTR_USER);
+			break;
+		case Opt_nouser_xattr:
+			clear_opt(EROFS_SB(sb), XATTR_USER);
+			break;
+#else
+		case Opt_user_xattr:
+			infoln("user_xattr options not supported");
+			break;
+		case Opt_nouser_xattr:
+			infoln("nouser_xattr options not supported");
+			break;
+#endif
+#ifdef CONFIG_EROFS_FS_POSIX_ACL
+		case Opt_acl:
+			set_opt(EROFS_SB(sb), POSIX_ACL);
+			break;
+		case Opt_noacl:
+			clear_opt(EROFS_SB(sb), POSIX_ACL);
+			break;
+#else
+		case Opt_acl:
+			infoln("acl options not supported");
+			break;
+		case Opt_noacl:
+			infoln("noacl options not supported");
+			break;
+#endif
 		case Opt_fault_injection:
 			err = erofs_build_fault_attr(EROFS_SB(sb), args);
 			if (err)
@@ -270,6 +319,10 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
 
 	sb->s_op = &erofs_sops;
 
+#ifdef CONFIG_EROFS_FS_XATTR
+	sb->s_xattr = erofs_xattr_handlers;
+#endif
+
 	/* set erofs default mount options */
 	default_options(sbi);
 
@@ -280,6 +333,11 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
 	if (!silent)
 		infoln("root inode @ nid %llu", ROOT_NID(sbi));
 
+	if (test_opt(sbi, POSIX_ACL))
+		sb->s_flags |= SB_POSIXACL;
+	else
+		sb->s_flags &= ~SB_POSIXACL;
+
 	/* get the root inode */
 	inode = erofs_iget(sb, ROOT_NID(sbi), true);
 	if (IS_ERR(inode))
@@ -393,6 +451,18 @@ static int erofs_show_options(struct seq_file *seq, struct dentry *root)
 {
 	struct erofs_sb_info *sbi __maybe_unused = EROFS_SB(root->d_sb);
 
+#ifdef CONFIG_EROFS_FS_XATTR
+	if (test_opt(sbi, XATTR_USER))
+		seq_puts(seq, ",user_xattr");
+	else
+		seq_puts(seq, ",nouser_xattr");
+#endif
+#ifdef CONFIG_EROFS_FS_POSIX_ACL
+	if (test_opt(sbi, POSIX_ACL))
+		seq_puts(seq, ",acl");
+	else
+		seq_puts(seq, ",noacl");
+#endif
 	if (test_opt(sbi, FAULT_INJECTION))
 		seq_printf(seq, ",fault_injection=%u",
 			   erofs_get_fault_rate(sbi));
@@ -411,6 +481,11 @@ static int erofs_remount(struct super_block *sb, int *flags, char *data)
 	if (err)
 		goto out;
 
+	if (test_opt(sbi, POSIX_ACL))
+		sb->s_flags |= SB_POSIXACL;
+	else
+		sb->s_flags &= ~SB_POSIXACL;
+
 	*flags |= SB_RDONLY;
 	return 0;
 out:
diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c
new file mode 100644
index 000000000000..148ceaf72790
--- /dev/null
+++ b/fs/erofs/xattr.c
@@ -0,0 +1,700 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/fs/erofs/xattr.c
+ *
+ * Copyright (C) 2017-2018 HUAWEI, Inc.
+ *             http://www.huawei.com/
+ * Created by Gao Xiang <gaoxiang25@huawei.com>
+ */
+#include <linux/security.h>
+#include "xattr.h"
+
+struct xattr_iter {
+	struct super_block *sb;
+	struct page *page;
+	void *kaddr;
+
+	erofs_blk_t blkaddr;
+	unsigned int ofs;
+};
+
+static inline void xattr_iter_end(struct xattr_iter *it, bool atomic)
+{
+	/* the only user of kunmap() is 'init_inode_xattrs' */
+	if (unlikely(!atomic))
+		kunmap(it->page);
+	else
+		kunmap_atomic(it->kaddr);
+
+	unlock_page(it->page);
+	put_page(it->page);
+}
+
+static inline void xattr_iter_end_final(struct xattr_iter *it)
+{
+	if (!it->page)
+		return;
+
+	xattr_iter_end(it, true);
+}
+
+static int init_inode_xattrs(struct inode *inode)
+{
+	struct erofs_vnode *const vi = EROFS_V(inode);
+	struct xattr_iter it;
+	unsigned int i;
+	struct erofs_xattr_ibody_header *ih;
+	struct super_block *sb;
+	struct erofs_sb_info *sbi;
+	bool atomic_map;
+	int ret = 0;
+
+	/* the most case is that xattrs of this inode are initialized. */
+	if (test_bit(EROFS_V_EA_INITED_BIT, &vi->flags))
+		return 0;
+
+	if (wait_on_bit_lock(&vi->flags, EROFS_V_BL_XATTR_BIT, TASK_KILLABLE))
+		return -ERESTARTSYS;
+
+	/* someone has initialized xattrs for us? */
+	if (test_bit(EROFS_V_EA_INITED_BIT, &vi->flags))
+		goto out_unlock;
+
+	/*
+	 * bypass all xattr operations if ->xattr_isize is not greater than
+	 * sizeof(struct erofs_xattr_ibody_header), in detail:
+	 * 1) it is not enough to contain erofs_xattr_ibody_header then
+	 *    ->xattr_isize should be 0 (it means no xattr);
+	 * 2) it is just to contain erofs_xattr_ibody_header, which is on-disk
+	 *    undefined right now (maybe use later with some new sb feature).
+	 */
+	if (vi->xattr_isize == sizeof(struct erofs_xattr_ibody_header)) {
+		errln("xattr_isize %d of nid %llu is not supported yet",
+		      vi->xattr_isize, vi->nid);
+		ret = -ENOTSUPP;
+		goto out_unlock;
+	} else if (vi->xattr_isize < sizeof(struct erofs_xattr_ibody_header)) {
+		if (unlikely(vi->xattr_isize)) {
+			DBG_BUGON(1);
+			ret = -EIO;
+			goto out_unlock;	/* xattr ondisk layout error */
+		}
+		ret = -ENOATTR;
+		goto out_unlock;
+	}
+
+	sb = inode->i_sb;
+	sbi = EROFS_SB(sb);
+	it.blkaddr = erofs_blknr(iloc(sbi, vi->nid) + vi->inode_isize);
+	it.ofs = erofs_blkoff(iloc(sbi, vi->nid) + vi->inode_isize);
+
+	it.page = erofs_get_inline_page(inode, it.blkaddr);
+	if (IS_ERR(it.page)) {
+		ret = PTR_ERR(it.page);
+		goto out_unlock;
+	}
+
+	/* read in shared xattr array (non-atomic, see kmalloc below) */
+	it.kaddr = kmap(it.page);
+	atomic_map = false;
+
+	ih = (struct erofs_xattr_ibody_header *)(it.kaddr + it.ofs);
+
+	vi->xattr_shared_count = ih->h_shared_count;
+	vi->xattr_shared_xattrs = kmalloc_array(vi->xattr_shared_count,
+						sizeof(uint), GFP_KERNEL);
+	if (!vi->xattr_shared_xattrs) {
+		xattr_iter_end(&it, atomic_map);
+		ret = -ENOMEM;
+		goto out_unlock;
+	}
+
+	/* let's skip ibody header */
+	it.ofs += sizeof(struct erofs_xattr_ibody_header);
+
+	for (i = 0; i < vi->xattr_shared_count; ++i) {
+		if (unlikely(it.ofs >= EROFS_BLKSIZ)) {
+			/* cannot be unaligned */
+			BUG_ON(it.ofs != EROFS_BLKSIZ);
+			xattr_iter_end(&it, atomic_map);
+
+			it.page = erofs_get_meta_page(sb, ++it.blkaddr,
+						      S_ISDIR(inode->i_mode));
+			if (IS_ERR(it.page)) {
+				kfree(vi->xattr_shared_xattrs);
+				vi->xattr_shared_xattrs = NULL;
+				ret = PTR_ERR(it.page);
+				goto out_unlock;
+			}
+
+			it.kaddr = kmap_atomic(it.page);
+			atomic_map = true;
+			it.ofs = 0;
+		}
+		vi->xattr_shared_xattrs[i] =
+			le32_to_cpu(*(__le32 *)(it.kaddr + it.ofs));
+		it.ofs += sizeof(__le32);
+	}
+	xattr_iter_end(&it, atomic_map);
+
+	set_bit(EROFS_V_EA_INITED_BIT, &vi->flags);
+
+out_unlock:
+	clear_and_wake_up_bit(EROFS_V_BL_XATTR_BIT, &vi->flags);
+	return ret;
+}
+
+/*
+ * the general idea for these return values is
+ * if    0 is returned, go on processing the current xattr;
+ *       1 (> 0) is returned, skip this round to process the next xattr;
+ *    -err (< 0) is returned, an error (maybe ENOXATTR) occurred
+ *                            and need to be handled
+ */
+struct xattr_iter_handlers {
+	int (*entry)(struct xattr_iter *_it, struct erofs_xattr_entry *entry);
+	int (*name)(struct xattr_iter *_it, unsigned int processed, char *buf,
+		    unsigned int len);
+	int (*alloc_buffer)(struct xattr_iter *_it, unsigned int value_sz);
+	void (*value)(struct xattr_iter *_it, unsigned int processed, char *buf,
+		      unsigned int len);
+};
+
+static inline int xattr_iter_fixup(struct xattr_iter *it)
+{
+	if (it->ofs < EROFS_BLKSIZ)
+		return 0;
+
+	xattr_iter_end(it, true);
+
+	it->blkaddr += erofs_blknr(it->ofs);
+
+	it->page = erofs_get_meta_page(it->sb, it->blkaddr, false);
+	if (IS_ERR(it->page)) {
+		int err = PTR_ERR(it->page);
+
+		it->page = NULL;
+		return err;
+	}
+
+	it->kaddr = kmap_atomic(it->page);
+	it->ofs = erofs_blkoff(it->ofs);
+	return 0;
+}
+
+static int inline_xattr_iter_begin(struct xattr_iter *it,
+				   struct inode *inode)
+{
+	struct erofs_vnode *const vi = EROFS_V(inode);
+	struct erofs_sb_info *const sbi = EROFS_SB(inode->i_sb);
+	unsigned int xattr_header_sz, inline_xattr_ofs;
+
+	xattr_header_sz = inlinexattr_header_size(inode);
+	if (unlikely(xattr_header_sz >= vi->xattr_isize)) {
+		BUG_ON(xattr_header_sz > vi->xattr_isize);
+		return -ENOATTR;
+	}
+
+	inline_xattr_ofs = vi->inode_isize + xattr_header_sz;
+
+	it->blkaddr = erofs_blknr(iloc(sbi, vi->nid) + inline_xattr_ofs);
+	it->ofs = erofs_blkoff(iloc(sbi, vi->nid) + inline_xattr_ofs);
+
+	it->page = erofs_get_inline_page(inode, it->blkaddr);
+	if (IS_ERR(it->page))
+		return PTR_ERR(it->page);
+
+	it->kaddr = kmap_atomic(it->page);
+	return vi->xattr_isize - xattr_header_sz;
+}
+
+/*
+ * Regardless of success or failure, `xattr_foreach' will end up with
+ * `ofs' pointing to the next xattr item rather than an arbitrary position.
+ */
+static int xattr_foreach(struct xattr_iter *it,
+			 const struct xattr_iter_handlers *op,
+			 unsigned int *tlimit)
+{
+	struct erofs_xattr_entry entry;
+	unsigned int value_sz, processed, slice;
+	int err;
+
+	/* 0. fixup blkaddr, ofs, ipage */
+	err = xattr_iter_fixup(it);
+	if (err)
+		return err;
+
+	/*
+	 * 1. read xattr entry to the memory,
+	 *    since we do EROFS_XATTR_ALIGN
+	 *    therefore entry should be in the page
+	 */
+	entry = *(struct erofs_xattr_entry *)(it->kaddr + it->ofs);
+	if (tlimit) {
+		unsigned int entry_sz = EROFS_XATTR_ENTRY_SIZE(&entry);
+
+		BUG_ON(*tlimit < entry_sz);
+		*tlimit -= entry_sz;
+	}
+
+	it->ofs += sizeof(struct erofs_xattr_entry);
+	value_sz = le16_to_cpu(entry.e_value_size);
+
+	/* handle entry */
+	err = op->entry(it, &entry);
+	if (err) {
+		it->ofs += entry.e_name_len + value_sz;
+		goto out;
+	}
+
+	/* 2. handle xattr name (ofs will finally be at the end of name) */
+	processed = 0;
+
+	while (processed < entry.e_name_len) {
+		if (it->ofs >= EROFS_BLKSIZ) {
+			BUG_ON(it->ofs > EROFS_BLKSIZ);
+
+			err = xattr_iter_fixup(it);
+			if (err)
+				goto out;
+			it->ofs = 0;
+		}
+
+		slice = min_t(unsigned int, PAGE_SIZE - it->ofs,
+			      entry.e_name_len - processed);
+
+		/* handle name */
+		err = op->name(it, processed, it->kaddr + it->ofs, slice);
+		if (err) {
+			it->ofs += entry.e_name_len - processed + value_sz;
+			goto out;
+		}
+
+		it->ofs += slice;
+		processed += slice;
+	}
+
+	/* 3. handle xattr value */
+	processed = 0;
+
+	if (op->alloc_buffer) {
+		err = op->alloc_buffer(it, value_sz);
+		if (err) {
+			it->ofs += value_sz;
+			goto out;
+		}
+	}
+
+	while (processed < value_sz) {
+		if (it->ofs >= EROFS_BLKSIZ) {
+			BUG_ON(it->ofs > EROFS_BLKSIZ);
+
+			err = xattr_iter_fixup(it);
+			if (err)
+				goto out;
+			it->ofs = 0;
+		}
+
+		slice = min_t(unsigned int, PAGE_SIZE - it->ofs,
+			      value_sz - processed);
+		op->value(it, processed, it->kaddr + it->ofs, slice);
+		it->ofs += slice;
+		processed += slice;
+	}
+
+out:
+	/* xattrs should be 4-byte aligned (on-disk constraint) */
+	it->ofs = EROFS_XATTR_ALIGN(it->ofs);
+	return err < 0 ? err : 0;
+}
+
+struct getxattr_iter {
+	struct xattr_iter it;
+
+	char *buffer;
+	int buffer_size, index;
+	struct qstr name;
+};
+
+static int xattr_entrymatch(struct xattr_iter *_it,
+			    struct erofs_xattr_entry *entry)
+{
+	struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
+
+	return (it->index != entry->e_name_index ||
+		it->name.len != entry->e_name_len) ? -ENOATTR : 0;
+}
+
+static int xattr_namematch(struct xattr_iter *_it,
+			   unsigned int processed, char *buf, unsigned int len)
+{
+	struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
+
+	return memcmp(buf, it->name.name + processed, len) ? -ENOATTR : 0;
+}
+
+static int xattr_checkbuffer(struct xattr_iter *_it,
+			     unsigned int value_sz)
+{
+	struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
+	int err = it->buffer_size < value_sz ? -ERANGE : 0;
+
+	it->buffer_size = value_sz;
+	return !it->buffer ? 1 : err;
+}
+
+static void xattr_copyvalue(struct xattr_iter *_it,
+			    unsigned int processed,
+			    char *buf, unsigned int len)
+{
+	struct getxattr_iter *it = container_of(_it, struct getxattr_iter, it);
+
+	memcpy(it->buffer + processed, buf, len);
+}
+
+static const struct xattr_iter_handlers find_xattr_handlers = {
+	.entry = xattr_entrymatch,
+	.name = xattr_namematch,
+	.alloc_buffer = xattr_checkbuffer,
+	.value = xattr_copyvalue
+};
+
+static int inline_getxattr(struct inode *inode, struct getxattr_iter *it)
+{
+	int ret;
+	unsigned int remaining;
+
+	ret = inline_xattr_iter_begin(&it->it, inode);
+	if (ret < 0)
+		return ret;
+
+	remaining = ret;
+	while (remaining) {
+		ret = xattr_foreach(&it->it, &find_xattr_handlers, &remaining);
+		if (ret != -ENOATTR)
+			break;
+	}
+	xattr_iter_end_final(&it->it);
+
+	return ret ? ret : it->buffer_size;
+}
+
+static int shared_getxattr(struct inode *inode, struct getxattr_iter *it)
+{
+	struct erofs_vnode *const vi = EROFS_V(inode);
+	struct super_block *const sb = inode->i_sb;
+	struct erofs_sb_info *const sbi = EROFS_SB(sb);
+	unsigned int i;
+	int ret = -ENOATTR;
+
+	for (i = 0; i < vi->xattr_shared_count; ++i) {
+		erofs_blk_t blkaddr =
+			xattrblock_addr(sbi, vi->xattr_shared_xattrs[i]);
+
+		it->it.ofs = xattrblock_offset(sbi, vi->xattr_shared_xattrs[i]);
+
+		if (!i || blkaddr != it->it.blkaddr) {
+			if (i)
+				xattr_iter_end(&it->it, true);
+
+			it->it.page = erofs_get_meta_page(sb, blkaddr, false);
+			if (IS_ERR(it->it.page))
+				return PTR_ERR(it->it.page);
+
+			it->it.kaddr = kmap_atomic(it->it.page);
+			it->it.blkaddr = blkaddr;
+		}
+
+		ret = xattr_foreach(&it->it, &find_xattr_handlers, NULL);
+		if (ret != -ENOATTR)
+			break;
+	}
+	if (vi->xattr_shared_count)
+		xattr_iter_end_final(&it->it);
+
+	return ret ? ret : it->buffer_size;
+}
+
+static bool erofs_xattr_user_list(struct dentry *dentry)
+{
+	return test_opt(EROFS_SB(dentry->d_sb), XATTR_USER);
+}
+
+static bool erofs_xattr_trusted_list(struct dentry *dentry)
+{
+	return capable(CAP_SYS_ADMIN);
+}
+
+int erofs_getxattr(struct inode *inode, int index,
+		   const char *name,
+		   void *buffer, size_t buffer_size)
+{
+	int ret;
+	struct getxattr_iter it;
+
+	if (unlikely(!name))
+		return -EINVAL;
+
+	ret = init_inode_xattrs(inode);
+	if (ret)
+		return ret;
+
+	it.index = index;
+
+	it.name.len = strlen(name);
+	if (it.name.len > EROFS_NAME_LEN)
+		return -ERANGE;
+	it.name.name = name;
+
+	it.buffer = buffer;
+	it.buffer_size = buffer_size;
+
+	it.it.sb = inode->i_sb;
+	ret = inline_getxattr(inode, &it);
+	if (ret == -ENOATTR)
+		ret = shared_getxattr(inode, &it);
+	return ret;
+}
+
+static int erofs_xattr_generic_get(const struct xattr_handler *handler,
+				   struct dentry *unused, struct inode *inode,
+				   const char *name, void *buffer, size_t size)
+{
+	struct erofs_sb_info *const sbi = EROFS_I_SB(inode);
+
+	switch (handler->flags) {
+	case EROFS_XATTR_INDEX_USER:
+		if (!test_opt(sbi, XATTR_USER))
+			return -EOPNOTSUPP;
+		break;
+	case EROFS_XATTR_INDEX_TRUSTED:
+		if (!capable(CAP_SYS_ADMIN))
+			return -EPERM;
+		break;
+	case EROFS_XATTR_INDEX_SECURITY:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return erofs_getxattr(inode, handler->flags, name, buffer, size);
+}
+
+const struct xattr_handler erofs_xattr_user_handler = {
+	.prefix	= XATTR_USER_PREFIX,
+	.flags	= EROFS_XATTR_INDEX_USER,
+	.list	= erofs_xattr_user_list,
+	.get	= erofs_xattr_generic_get,
+};
+
+const struct xattr_handler erofs_xattr_trusted_handler = {
+	.prefix	= XATTR_TRUSTED_PREFIX,
+	.flags	= EROFS_XATTR_INDEX_TRUSTED,
+	.list	= erofs_xattr_trusted_list,
+	.get	= erofs_xattr_generic_get,
+};
+
+#ifdef CONFIG_EROFS_FS_SECURITY
+const struct xattr_handler __maybe_unused erofs_xattr_security_handler = {
+	.prefix	= XATTR_SECURITY_PREFIX,
+	.flags	= EROFS_XATTR_INDEX_SECURITY,
+	.get	= erofs_xattr_generic_get,
+};
+#endif
+
+const struct xattr_handler *erofs_xattr_handlers[] = {
+	&erofs_xattr_user_handler,
+#ifdef CONFIG_EROFS_FS_POSIX_ACL
+	&posix_acl_access_xattr_handler,
+	&posix_acl_default_xattr_handler,
+#endif
+	&erofs_xattr_trusted_handler,
+#ifdef CONFIG_EROFS_FS_SECURITY
+	&erofs_xattr_security_handler,
+#endif
+	NULL,
+};
+
+struct listxattr_iter {
+	struct xattr_iter it;
+
+	struct dentry *dentry;
+	char *buffer;
+	int buffer_size, buffer_ofs;
+};
+
+static int xattr_entrylist(struct xattr_iter *_it,
+			   struct erofs_xattr_entry *entry)
+{
+	struct listxattr_iter *it =
+		container_of(_it, struct listxattr_iter, it);
+	unsigned int prefix_len;
+	const char *prefix;
+
+	const struct xattr_handler *h =
+		erofs_xattr_handler(entry->e_name_index);
+
+	if (!h || (h->list && !h->list(it->dentry)))
+		return 1;
+
+	prefix = xattr_prefix(h);
+	prefix_len = strlen(prefix);
+
+	if (!it->buffer) {
+		it->buffer_ofs += prefix_len + entry->e_name_len + 1;
+		return 1;
+	}
+
+	if (it->buffer_ofs + prefix_len
+		+ entry->e_name_len + 1 > it->buffer_size)
+		return -ERANGE;
+
+	memcpy(it->buffer + it->buffer_ofs, prefix, prefix_len);
+	it->buffer_ofs += prefix_len;
+	return 0;
+}
+
+static int xattr_namelist(struct xattr_iter *_it,
+			  unsigned int processed, char *buf, unsigned int len)
+{
+	struct listxattr_iter *it =
+		container_of(_it, struct listxattr_iter, it);
+
+	memcpy(it->buffer + it->buffer_ofs, buf, len);
+	it->buffer_ofs += len;
+	return 0;
+}
+
+static int xattr_skipvalue(struct xattr_iter *_it,
+			   unsigned int value_sz)
+{
+	struct listxattr_iter *it =
+		container_of(_it, struct listxattr_iter, it);
+
+	it->buffer[it->buffer_ofs++] = '\0';
+	return 1;
+}
+
+static const struct xattr_iter_handlers list_xattr_handlers = {
+	.entry = xattr_entrylist,
+	.name = xattr_namelist,
+	.alloc_buffer = xattr_skipvalue,
+	.value = NULL
+};
+
+static int inline_listxattr(struct listxattr_iter *it)
+{
+	int ret;
+	unsigned int remaining;
+
+	ret = inline_xattr_iter_begin(&it->it, d_inode(it->dentry));
+	if (ret < 0)
+		return ret;
+
+	remaining = ret;
+	while (remaining) {
+		ret = xattr_foreach(&it->it, &list_xattr_handlers, &remaining);
+		if (ret)
+			break;
+	}
+	xattr_iter_end_final(&it->it);
+	return ret ? ret : it->buffer_ofs;
+}
+
+static int shared_listxattr(struct listxattr_iter *it)
+{
+	struct inode *const inode = d_inode(it->dentry);
+	struct erofs_vnode *const vi = EROFS_V(inode);
+	struct super_block *const sb = inode->i_sb;
+	struct erofs_sb_info *const sbi = EROFS_SB(sb);
+	unsigned int i;
+	int ret = 0;
+
+	for (i = 0; i < vi->xattr_shared_count; ++i) {
+		erofs_blk_t blkaddr =
+			xattrblock_addr(sbi, vi->xattr_shared_xattrs[i]);
+
+		it->it.ofs = xattrblock_offset(sbi, vi->xattr_shared_xattrs[i]);
+		if (!i || blkaddr != it->it.blkaddr) {
+			if (i)
+				xattr_iter_end(&it->it, true);
+
+			it->it.page = erofs_get_meta_page(sb, blkaddr, false);
+			if (IS_ERR(it->it.page))
+				return PTR_ERR(it->it.page);
+
+			it->it.kaddr = kmap_atomic(it->it.page);
+			it->it.blkaddr = blkaddr;
+		}
+
+		ret = xattr_foreach(&it->it, &list_xattr_handlers, NULL);
+		if (ret)
+			break;
+	}
+	if (vi->xattr_shared_count)
+		xattr_iter_end_final(&it->it);
+
+	return ret ? ret : it->buffer_ofs;
+}
+
+ssize_t erofs_listxattr(struct dentry *dentry,
+			char *buffer, size_t buffer_size)
+{
+	int ret;
+	struct listxattr_iter it;
+
+	ret = init_inode_xattrs(d_inode(dentry));
+	if (ret)
+		return ret;
+
+	it.dentry = dentry;
+	it.buffer = buffer;
+	it.buffer_size = buffer_size;
+	it.buffer_ofs = 0;
+
+	it.it.sb = dentry->d_sb;
+
+	ret = inline_listxattr(&it);
+	if (ret < 0 && ret != -ENOATTR)
+		return ret;
+	return shared_listxattr(&it);
+}
+
+#ifdef CONFIG_EROFS_FS_POSIX_ACL
+struct posix_acl *erofs_get_acl(struct inode *inode, int type)
+{
+	struct posix_acl *acl;
+	int prefix, rc;
+	char *value = NULL;
+
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		prefix = EROFS_XATTR_INDEX_POSIX_ACL_ACCESS;
+		break;
+	case ACL_TYPE_DEFAULT:
+		prefix = EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT;
+		break;
+	default:
+		return ERR_PTR(-EINVAL);
+	}
+
+	rc = erofs_getxattr(inode, prefix, "", NULL, 0);
+	if (rc > 0) {
+		value = kmalloc(rc, GFP_KERNEL);
+		if (!value)
+			return ERR_PTR(-ENOMEM);
+		rc = erofs_getxattr(inode, prefix, "", value, rc);
+	}
+
+	if (rc == -ENOATTR)
+		acl = NULL;
+	else if (rc < 0)
+		acl = ERR_PTR(rc);
+	else
+		acl = posix_acl_from_xattr(&init_user_ns, value, rc);
+	kfree(value);
+	return acl;
+}
+#endif
+
diff --git a/fs/erofs/xattr.h b/fs/erofs/xattr.h
new file mode 100644
index 000000000000..d4213fff57e7
--- /dev/null
+++ b/fs/erofs/xattr.h
@@ -0,0 +1,94 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * linux/fs/erofs/xattr.h
+ *
+ * Copyright (C) 2017-2018 HUAWEI, Inc.
+ *             http://www.huawei.com/
+ * Created by Gao Xiang <gaoxiang25@huawei.com>
+ */
+#ifndef __EROFS_XATTR_H
+#define __EROFS_XATTR_H
+
+#include "internal.h"
+#include <linux/posix_acl_xattr.h>
+#include <linux/xattr.h>
+
+/* Attribute not found */
+#define ENOATTR         ENODATA
+
+static inline unsigned int inlinexattr_header_size(struct inode *inode)
+{
+	return sizeof(struct erofs_xattr_ibody_header)
+		+ sizeof(u32) * EROFS_V(inode)->xattr_shared_count;
+}
+
+static inline erofs_blk_t xattrblock_addr(struct erofs_sb_info *sbi,
+					  unsigned int xattr_id)
+{
+#ifdef CONFIG_EROFS_FS_XATTR
+	return sbi->xattr_blkaddr +
+		xattr_id * sizeof(__u32) / EROFS_BLKSIZ;
+#else
+	return 0;
+#endif
+}
+
+static inline unsigned int xattrblock_offset(struct erofs_sb_info *sbi,
+					     unsigned int xattr_id)
+{
+	return (xattr_id * sizeof(__u32)) % EROFS_BLKSIZ;
+}
+
+#ifdef CONFIG_EROFS_FS_XATTR
+extern const struct xattr_handler erofs_xattr_user_handler;
+extern const struct xattr_handler erofs_xattr_trusted_handler;
+#ifdef CONFIG_EROFS_FS_SECURITY
+extern const struct xattr_handler erofs_xattr_security_handler;
+#endif
+
+static inline const struct xattr_handler *erofs_xattr_handler(unsigned int idx)
+{
+static const struct xattr_handler *xattr_handler_map[] = {
+	[EROFS_XATTR_INDEX_USER] = &erofs_xattr_user_handler,
+#ifdef CONFIG_EROFS_FS_POSIX_ACL
+	[EROFS_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler,
+	[EROFS_XATTR_INDEX_POSIX_ACL_DEFAULT] =
+		&posix_acl_default_xattr_handler,
+#endif
+	[EROFS_XATTR_INDEX_TRUSTED] = &erofs_xattr_trusted_handler,
+#ifdef CONFIG_EROFS_FS_SECURITY
+	[EROFS_XATTR_INDEX_SECURITY] = &erofs_xattr_security_handler,
+#endif
+};
+
+	return idx && idx < ARRAY_SIZE(xattr_handler_map) ?
+		xattr_handler_map[idx] : NULL;
+}
+
+extern const struct xattr_handler *erofs_xattr_handlers[];
+
+int erofs_getxattr(struct inode *, int, const char *, void *, size_t);
+ssize_t erofs_listxattr(struct dentry *, char *, size_t);
+#else
+static inline int erofs_getxattr(struct inode *inode, int index,
+				 const char *name, void *buffer,
+				 size_t buffer_size)
+{
+	return -ENOTSUPP;
+}
+
+static inline ssize_t erofs_listxattr(struct dentry *dentry,
+				      char *buffer, size_t buffer_size)
+{
+	return -ENOTSUPP;
+}
+#endif	/* !CONFIG_EROFS_FS_XATTR */
+
+#ifdef CONFIG_EROFS_FS_POSIX_ACL
+struct posix_acl *erofs_get_acl(struct inode *inode, int type);
+#else
+#define erofs_get_acl	(NULL)
+#endif
+
+#endif
+
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v6 12/24] erofs: introduce tagged pointer
  2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
                   ` (10 preceding siblings ...)
  2019-08-02 12:53 ` [PATCH v6 11/24] erofs: introduce xattr & posixacl support Gao Xiang
@ 2019-08-02 12:53 ` Gao Xiang
  2019-08-02 12:53 ` [PATCH v6 13/24] erofs: add compression indexes support Gao Xiang
                   ` (12 subsequent siblings)
  24 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-02 12:53 UTC (permalink / raw)
  To: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds
  Cc: linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei, Gao Xiang

Currently kernel has scattered tagged pointer usages
hacked by hand in plain code, without a unique and
portable functionset to highlight the tagged pointer
itself and wrap these hacked code in order to clean up
all over meaningless magic masks.

This patch introduces simple generic methods to fold
tags into a pointer integer. Currently it supports
the last n bits of the pointer for tags, which can be
selected by users.

In addition, it will also be used for the upcoming EROFS
filesystem, which heavily uses tagged pointer pproach
 to reduce extra memory allocation.

Link: https://en.wikipedia.org/wiki/Tagged_pointer

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/tagptr.h | 110 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 110 insertions(+)
 create mode 100644 fs/erofs/tagptr.h

diff --git a/fs/erofs/tagptr.h b/fs/erofs/tagptr.h
new file mode 100644
index 000000000000..a72897c86744
--- /dev/null
+++ b/fs/erofs/tagptr.h
@@ -0,0 +1,110 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * A tagged pointer implementation
+ *
+ * Copyright (C) 2018 Gao Xiang <gaoxiang25@huawei.com>
+ */
+#ifndef __EROFS_FS_TAGPTR_H
+#define __EROFS_FS_TAGPTR_H
+
+#include <linux/types.h>
+#include <linux/build_bug.h>
+
+/*
+ * the name of tagged pointer types are tagptr{1, 2, 3...}_t
+ * avoid directly using the internal structs __tagptr{1, 2, 3...}
+ */
+#define __MAKE_TAGPTR(n) \
+typedef struct __tagptr##n {	\
+	uintptr_t v;	\
+} tagptr##n##_t;
+
+__MAKE_TAGPTR(1)
+__MAKE_TAGPTR(2)
+__MAKE_TAGPTR(3)
+__MAKE_TAGPTR(4)
+
+#undef __MAKE_TAGPTR
+
+extern void __compiletime_error("bad tagptr tags")
+	__bad_tagptr_tags(void);
+
+extern void __compiletime_error("bad tagptr type")
+	__bad_tagptr_type(void);
+
+/* fix the broken usage of "#define tagptr2_t tagptr3_t" by users */
+#define __tagptr_mask_1(ptr, n)	\
+	__builtin_types_compatible_p(typeof(ptr), struct __tagptr##n) ? \
+		(1UL << (n)) - 1 :
+
+#define __tagptr_mask(ptr)	(\
+	__tagptr_mask_1(ptr, 1) ( \
+	__tagptr_mask_1(ptr, 2) ( \
+	__tagptr_mask_1(ptr, 3) ( \
+	__tagptr_mask_1(ptr, 4) ( \
+	__bad_tagptr_type(), 0)))))
+
+/* generate a tagged pointer from a raw value */
+#define tagptr_init(type, val) \
+	((typeof(type)){ .v = (uintptr_t)(val) })
+
+/*
+ * directly cast a tagged pointer to the native pointer type, which
+ * could be used for backward compatibility of existing code.
+ */
+#define tagptr_cast_ptr(tptr) ((void *)(tptr).v)
+
+/* encode tagged pointers */
+#define tagptr_fold(type, ptr, _tags) ({ \
+	const typeof(_tags) tags = (_tags); \
+	if (__builtin_constant_p(tags) && (tags & ~__tagptr_mask(type))) \
+		__bad_tagptr_tags(); \
+tagptr_init(type, (uintptr_t)(ptr) | tags); })
+
+/* decode tagged pointers */
+#define tagptr_unfold_ptr(tptr) \
+	((void *)((tptr).v & ~__tagptr_mask(tptr)))
+
+#define tagptr_unfold_tags(tptr) \
+	((tptr).v & __tagptr_mask(tptr))
+
+/* operations for the tagger pointer */
+#define tagptr_eq(_tptr1, _tptr2) ({ \
+	typeof(_tptr1) tptr1 = (_tptr1); \
+	typeof(_tptr2) tptr2 = (_tptr2); \
+	(void)(&tptr1 == &tptr2); \
+(tptr1).v == (tptr2).v; })
+
+/* lock-free CAS operation */
+#define tagptr_cmpxchg(_ptptr, _o, _n) ({ \
+	typeof(_ptptr) ptptr = (_ptptr); \
+	typeof(_o) o = (_o); \
+	typeof(_n) n = (_n); \
+	(void)(&o == &n); \
+	(void)(&o == ptptr); \
+tagptr_init(o, cmpxchg(&ptptr->v, o.v, n.v)); })
+
+/* wrap WRITE_ONCE if atomic update is needed */
+#define tagptr_replace_tags(_ptptr, tags) ({ \
+	typeof(_ptptr) ptptr = (_ptptr); \
+	*ptptr = tagptr_fold(*ptptr, tagptr_unfold_ptr(*ptptr), tags); \
+*ptptr; })
+
+#define tagptr_set_tags(_ptptr, _tags) ({ \
+	typeof(_ptptr) ptptr = (_ptptr); \
+	const typeof(_tags) tags = (_tags); \
+	if (__builtin_constant_p(tags) && (tags & ~__tagptr_mask(*ptptr))) \
+		__bad_tagptr_tags(); \
+	ptptr->v |= tags; \
+*ptptr; })
+
+#define tagptr_clear_tags(_ptptr, _tags) ({ \
+	typeof(_ptptr) ptptr = (_ptptr); \
+	const typeof(_tags) tags = (_tags); \
+	if (__builtin_constant_p(tags) && (tags & ~__tagptr_mask(*ptptr))) \
+		__bad_tagptr_tags(); \
+	ptptr->v &= ~tags; \
+*ptptr; })
+
+#endif	/* __EROFS_FS_TAGPTR_H */
+
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v6 13/24] erofs: add compression indexes support
  2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
                   ` (11 preceding siblings ...)
  2019-08-02 12:53 ` [PATCH v6 12/24] erofs: introduce tagged pointer Gao Xiang
@ 2019-08-02 12:53 ` Gao Xiang
  2019-08-02 12:53 ` [PATCH v6 14/24] erofs: introduce superblock registration Gao Xiang
                   ` (11 subsequent siblings)
  24 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-02 12:53 UTC (permalink / raw)
  To: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds
  Cc: linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei, Gao Xiang

This patch adds EROFS compression indexes support,
including legacy and compacted 2/4B indexes.

In addition, it introduces an iterable L2P mapping
operation called 'z_erofs_map_blocks_iter'.

Compared with 'erofs_map_blocks', it avoids a number
of redundant 'release and regrab' processes if they
request the same meta page.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/Kconfig             |   9 +
 fs/erofs/Makefile            |   1 +
 fs/erofs/data.c              |  10 +-
 fs/erofs/inode.c             |   2 +-
 fs/erofs/internal.h          |  35 ++-
 fs/erofs/zmap.c              | 460 +++++++++++++++++++++++++++++++++++
 include/trace/events/erofs.h |  17 +-
 7 files changed, 529 insertions(+), 5 deletions(-)
 create mode 100644 fs/erofs/zmap.c

diff --git a/fs/erofs/Kconfig b/fs/erofs/Kconfig
index c5e7c5ae026e..a475fbebb831 100644
--- a/fs/erofs/Kconfig
+++ b/fs/erofs/Kconfig
@@ -72,3 +72,12 @@ config EROFS_FS_SECURITY
 
 	  If you are not using a security module, say N.
 
+config EROFS_FS_ZIP
+	bool "EROFS Data Compression Support"
+	depends on EROFS_FS
+	select LZ4_DECOMPRESS
+	help
+	  Enable fixed-sized output compression for EROFS.
+
+	  If you don't want to enable compression feature, say N.
+
diff --git a/fs/erofs/Makefile b/fs/erofs/Makefile
index 190a73083f23..481a966caf06 100644
--- a/fs/erofs/Makefile
+++ b/fs/erofs/Makefile
@@ -7,4 +7,5 @@ ccflags-y += -DEROFS_VERSION=\"$(EROFS_VERSION)\"
 obj-$(CONFIG_EROFS_FS) += erofs.o
 erofs-objs := super.o inode.o data.o namei.o dir.o
 erofs-$(CONFIG_EROFS_FS_XATTR) += xattr.o
+erofs-$(CONFIG_EROFS_FS_ZIP) += zmap.o
 
diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index 9bb18fba773a..4d0123ef15f5 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -170,9 +170,15 @@ static int erofs_map_blocks_flatmode(struct inode *inode,
 int erofs_map_blocks(struct inode *inode,
 		     struct erofs_map_blocks *map, int flags)
 {
-	if (is_inode_layout_compression(inode))
-		return -ENOTSUPP;
+	if (unlikely(is_inode_layout_compression(inode))) {
+		int err = z_erofs_map_blocks_iter(inode, map, flags);
 
+		if (map->mpage) {
+			put_page(map->mpage);
+			map->mpage = NULL;
+		}
+		return err;
+	}
 	return erofs_map_blocks_flatmode(inode, map, flags);
 }
 
diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index aee53988aef5..2c771063889b 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -205,7 +205,7 @@ static int fill_inode(struct inode *inode, int isdir)
 		}
 
 		if (is_inode_layout_compression(inode)) {
-			err = -ENOTSUPP;
+			err = z_erofs_fill_inode(inode);
 			goto out_unlock;
 		}
 
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 004d5dbf2e7a..d3a703017233 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -174,9 +174,12 @@ static inline erofs_off_t iloc(struct erofs_sb_info *sbi, erofs_nid_t nid)
 
 /* atomic flag definitions */
 #define EROFS_V_EA_INITED_BIT	0
+#define EROFS_V_Z_INITED_BIT	1
 
 /* bitlock definitions (arranged in reverse order) */
 #define EROFS_V_BL_XATTR_BIT	(BITS_PER_LONG - 1)
+#define EROFS_V_BL_Z_BIT	(BITS_PER_LONG - 2)
+
 struct erofs_vnode {
 	erofs_nid_t nid;
 
@@ -190,7 +193,17 @@ struct erofs_vnode {
 	unsigned int xattr_shared_count;
 	unsigned int *xattr_shared_xattrs;
 
-	erofs_blk_t raw_blkaddr;
+	union {
+		erofs_blk_t raw_blkaddr;
+#ifdef CONFIG_EROFS_FS_ZIP
+		struct {
+			unsigned short z_advise;
+			unsigned char  z_algorithmtype[2];
+			unsigned char  z_logical_clusterbits;
+			unsigned char  z_physical_clusterbits[2];
+		};
+#endif	/* CONFIG_EROFS_FS_ZIP */
+	};
 	/* the corresponding vfs inode */
 	struct inode vfs_inode;
 };
@@ -263,6 +276,10 @@ enum {
 #define EROFS_MAP_MAPPED	(1 << BH_Mapped)
 /* Located in metadata (could be copied from bd_inode) */
 #define EROFS_MAP_META		(1 << BH_Meta)
+/* The extent has been compressed */
+#define EROFS_MAP_ZIPPED	(1 << BH_Zipped)
+/* The length of extent is full */
+#define EROFS_MAP_FULL_MAPPED	(1 << BH_FullMapped)
 
 struct erofs_map_blocks {
 	erofs_off_t m_pa, m_la;
@@ -276,6 +293,22 @@ struct erofs_map_blocks {
 /* Flags used by erofs_map_blocks() */
 #define EROFS_GET_BLOCKS_RAW    0x0001
 
+/* zmap.c */
+#ifdef CONFIG_EROFS_FS_ZIP
+int z_erofs_fill_inode(struct inode *inode);
+int z_erofs_map_blocks_iter(struct inode *inode,
+			    struct erofs_map_blocks *map,
+			    int flags);
+#else
+static inline int z_erofs_fill_inode(struct inode *inode) { return -ENOTSUPP; }
+static inline int z_erofs_map_blocks_iter(struct inode *inode,
+					  struct erofs_map_blocks *map,
+					  int flags)
+{
+	return -ENOTSUPP;
+}
+#endif	/* !CONFIG_EROFS_FS_ZIP */
+
 /* data.c */
 static inline struct bio *erofs_grab_bio(struct super_block *sb,
 					 erofs_blk_t blkaddr,
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
new file mode 100644
index 000000000000..8cd55c33f50b
--- /dev/null
+++ b/fs/erofs/zmap.c
@@ -0,0 +1,460 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/fs/erofs/zmap.c
+ *
+ * Copyright (C) 2018-2019 HUAWEI, Inc.
+ *             http://www.huawei.com/
+ * Created by Gao Xiang <gaoxiang25@huawei.com>
+ */
+#include "internal.h"
+#include <asm/unaligned.h>
+#include <trace/events/erofs.h>
+
+int z_erofs_fill_inode(struct inode *inode)
+{
+	struct erofs_vnode *const vi = EROFS_V(inode);
+
+	if (vi->datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY) {
+		vi->z_advise = 0;
+		vi->z_algorithmtype[0] = 0;
+		vi->z_algorithmtype[1] = 0;
+		vi->z_logical_clusterbits = LOG_BLOCK_SIZE;
+		vi->z_physical_clusterbits[0] = vi->z_logical_clusterbits;
+		vi->z_physical_clusterbits[1] = vi->z_logical_clusterbits;
+		set_bit(EROFS_V_Z_INITED_BIT, &vi->flags);
+	}
+	return -ENOTSUPP;
+}
+
+static int fill_inode_lazy(struct inode *inode)
+{
+	struct erofs_vnode *const vi = EROFS_V(inode);
+	struct super_block *const sb = inode->i_sb;
+	int err;
+	erofs_off_t pos;
+	struct page *page;
+	void *kaddr;
+	struct z_erofs_map_header *h;
+
+	if (test_bit(EROFS_V_Z_INITED_BIT, &vi->flags))
+		return 0;
+
+	if (wait_on_bit_lock(&vi->flags, EROFS_V_BL_Z_BIT, TASK_KILLABLE))
+		return -ERESTARTSYS;
+
+	err = 0;
+	if (test_bit(EROFS_V_Z_INITED_BIT, &vi->flags))
+		goto out_unlock;
+
+	DBG_BUGON(vi->datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY);
+
+	pos = ALIGN(iloc(EROFS_SB(sb), vi->nid) + vi->inode_isize +
+		    vi->xattr_isize, 8);
+	page = erofs_get_meta_page(sb, erofs_blknr(pos), false);
+	if (IS_ERR(page)) {
+		err = PTR_ERR(page);
+		goto out_unlock;
+	}
+
+	kaddr = kmap_atomic(page);
+
+	h = kaddr + erofs_blkoff(pos);
+	vi->z_advise = le16_to_cpu(h->h_advise);
+	vi->z_algorithmtype[0] = h->h_algorithmtype & 15;
+	vi->z_algorithmtype[1] = h->h_algorithmtype >> 4;
+
+	if (vi->z_algorithmtype[0] >= Z_EROFS_COMPRESSION_MAX) {
+		errln("unknown compression format %u for nid %llu, please upgrade kernel",
+		      vi->z_algorithmtype[0], vi->nid);
+		err = -ENOTSUPP;
+		goto unmap_done;
+	}
+
+	vi->z_logical_clusterbits = LOG_BLOCK_SIZE + (h->h_clusterbits & 7);
+	vi->z_physical_clusterbits[0] = vi->z_logical_clusterbits +
+					((h->h_clusterbits >> 3) & 3);
+
+	if (vi->z_physical_clusterbits[0] != LOG_BLOCK_SIZE) {
+		errln("unsupported physical clusterbits %u for nid %llu, please upgrade kernel",
+		      vi->z_physical_clusterbits[0], vi->nid);
+		err = -ENOTSUPP;
+		goto unmap_done;
+	}
+
+	vi->z_physical_clusterbits[1] = vi->z_logical_clusterbits +
+					((h->h_clusterbits >> 5) & 7);
+unmap_done:
+	kunmap_atomic(kaddr);
+	unlock_page(page);
+	put_page(page);
+
+	set_bit(EROFS_V_Z_INITED_BIT, &vi->flags);
+out_unlock:
+	clear_and_wake_up_bit(EROFS_V_BL_Z_BIT, &vi->flags);
+	return err;
+}
+
+struct z_erofs_maprecorder {
+	struct inode *inode;
+	struct erofs_map_blocks *map;
+	void *kaddr;
+
+	unsigned long lcn;
+	/* compression extent information gathered */
+	u8  type;
+	u16 clusterofs;
+	u16 delta[2];
+	erofs_blk_t pblk;
+};
+
+static int z_erofs_reload_indexes(struct z_erofs_maprecorder *m,
+				  erofs_blk_t eblk)
+{
+	struct super_block *const sb = m->inode->i_sb;
+	struct erofs_map_blocks *const map = m->map;
+	struct page *mpage = map->mpage;
+
+	if (mpage) {
+		if (mpage->index == eblk) {
+			if (!m->kaddr)
+				m->kaddr = kmap_atomic(mpage);
+			return 0;
+		}
+
+		if (m->kaddr) {
+			kunmap_atomic(m->kaddr);
+			m->kaddr = NULL;
+		}
+		put_page(mpage);
+	}
+
+	mpage = erofs_get_meta_page(sb, eblk, false);
+	if (IS_ERR(mpage)) {
+		map->mpage = NULL;
+		return PTR_ERR(mpage);
+	}
+	m->kaddr = kmap_atomic(mpage);
+	unlock_page(mpage);
+	map->mpage = mpage;
+	return 0;
+}
+
+static int vle_legacy_load_cluster_from_disk(struct z_erofs_maprecorder *m,
+					     unsigned long lcn)
+{
+	struct inode *const inode = m->inode;
+	struct erofs_vnode *const vi = EROFS_V(inode);
+	const erofs_off_t ibase = iloc(EROFS_I_SB(inode), vi->nid);
+	const erofs_off_t pos =
+		Z_EROFS_VLE_LEGACY_INDEX_ALIGN(ibase + vi->inode_isize +
+					       vi->xattr_isize) +
+		lcn * sizeof(struct z_erofs_vle_decompressed_index);
+	struct z_erofs_vle_decompressed_index *di;
+	unsigned int advise, type;
+	int err;
+
+	err = z_erofs_reload_indexes(m, erofs_blknr(pos));
+	if (err)
+		return err;
+
+	m->lcn = lcn;
+	di = m->kaddr + erofs_blkoff(pos);
+
+	advise = le16_to_cpu(di->di_advise);
+	type = (advise >> Z_EROFS_VLE_DI_CLUSTER_TYPE_BIT) &
+		((1 << Z_EROFS_VLE_DI_CLUSTER_TYPE_BITS) - 1);
+	switch (type) {
+	case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
+		m->clusterofs = 1 << vi->z_logical_clusterbits;
+		m->delta[0] = le16_to_cpu(di->di_u.delta[0]);
+		m->delta[1] = le16_to_cpu(di->di_u.delta[1]);
+		break;
+	case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
+	case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
+		m->clusterofs = le16_to_cpu(di->di_clusterofs);
+		m->pblk = le32_to_cpu(di->di_u.blkaddr);
+		break;
+	default:
+		DBG_BUGON(1);
+		return -EIO;
+	}
+	m->type = type;
+	return 0;
+}
+
+static unsigned int decode_compactedbits(unsigned int lobits,
+					 unsigned int lomask,
+					 u8 *in, unsigned int pos, u8 *type)
+{
+	const unsigned int v = get_unaligned_le32(in + pos / 8) >> (pos & 7);
+	const unsigned int lo = v & lomask;
+
+	*type = (v >> lobits) & 3;
+	return lo;
+}
+
+static int unpack_compacted_index(struct z_erofs_maprecorder *m,
+				  unsigned int amortizedshift,
+				  unsigned int eofs)
+{
+	struct erofs_vnode *const vi = EROFS_V(m->inode);
+	const unsigned int lclusterbits = vi->z_logical_clusterbits;
+	const unsigned int lomask = (1 << lclusterbits) - 1;
+	unsigned int vcnt, base, lo, encodebits, nblk;
+	int i;
+	u8 *in, type;
+
+	if (1 << amortizedshift == 4)
+		vcnt = 2;
+	else if (1 << amortizedshift == 2 && lclusterbits == 12)
+		vcnt = 16;
+	else
+		return -ENOTSUPP;
+
+	encodebits = ((vcnt << amortizedshift) - sizeof(__le32)) * 8 / vcnt;
+	base = round_down(eofs, vcnt << amortizedshift);
+	in = m->kaddr + base;
+
+	i = (eofs - base) >> amortizedshift;
+
+	lo = decode_compactedbits(lclusterbits, lomask,
+				  in, encodebits * i, &type);
+	m->type = type;
+	if (type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD) {
+		m->clusterofs = 1 << lclusterbits;
+		if (i + 1 != vcnt) {
+			m->delta[0] = lo;
+			return 0;
+		}
+		/*
+		 * since the last lcluster in the pack is special,
+		 * of which lo saves delta[1] rather than delta[0].
+		 * Hence, get delta[0] by the previous lcluster indirectly.
+		 */
+		lo = decode_compactedbits(lclusterbits, lomask,
+					  in, encodebits * (i - 1), &type);
+		if (type != Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD)
+			lo = 0;
+		m->delta[0] = lo + 1;
+		return 0;
+	}
+	m->clusterofs = lo;
+	m->delta[0] = 0;
+	/* figout out blkaddr (pblk) for HEAD lclusters */
+	nblk = 1;
+	while (i > 0) {
+		--i;
+		lo = decode_compactedbits(lclusterbits, lomask,
+					  in, encodebits * i, &type);
+		if (type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD)
+			i -= lo;
+
+		if (i >= 0)
+			++nblk;
+	}
+	in += (vcnt << amortizedshift) - sizeof(__le32);
+	m->pblk = le32_to_cpu(*(__le32 *)in) + nblk;
+	return 0;
+}
+
+static int compacted_load_cluster_from_disk(struct z_erofs_maprecorder *m,
+					    unsigned long lcn)
+{
+	struct inode *const inode = m->inode;
+	struct erofs_vnode *const vi = EROFS_V(inode);
+	const unsigned int lclusterbits = vi->z_logical_clusterbits;
+	const erofs_off_t ebase = ALIGN(iloc(EROFS_I_SB(inode), vi->nid) +
+					vi->inode_isize + vi->xattr_isize, 8) +
+		sizeof(struct z_erofs_map_header);
+	const unsigned int totalidx = DIV_ROUND_UP(inode->i_size, EROFS_BLKSIZ);
+	unsigned int compacted_4b_initial, compacted_2b;
+	unsigned int amortizedshift;
+	erofs_off_t pos;
+	int err;
+
+	if (lclusterbits != 12)
+		return -ENOTSUPP;
+
+	if (lcn >= totalidx)
+		return -EINVAL;
+
+	m->lcn = lcn;
+	/* used to align to 32-byte (compacted_2b) alignment */
+	compacted_4b_initial = (32 - ebase % 32) / 4;
+	if (compacted_4b_initial == 32 / 4)
+		compacted_4b_initial = 0;
+
+	if (vi->z_advise & Z_EROFS_ADVISE_COMPACTED_2B)
+		compacted_2b = rounddown(totalidx - compacted_4b_initial, 16);
+	else
+		compacted_2b = 0;
+
+	pos = ebase;
+	if (lcn < compacted_4b_initial) {
+		amortizedshift = 2;
+		goto out;
+	}
+	pos += compacted_4b_initial * 4;
+	lcn -= compacted_4b_initial;
+
+	if (lcn < compacted_2b) {
+		amortizedshift = 1;
+		goto out;
+	}
+	pos += compacted_2b * 2;
+	lcn -= compacted_2b;
+	amortizedshift = 2;
+out:
+	pos += lcn * (1 << amortizedshift);
+	err = z_erofs_reload_indexes(m, erofs_blknr(pos));
+	if (err)
+		return err;
+	return unpack_compacted_index(m, amortizedshift, erofs_blkoff(pos));
+}
+
+static int vle_load_cluster_from_disk(struct z_erofs_maprecorder *m,
+				      unsigned int lcn)
+{
+	const unsigned int datamode = EROFS_V(m->inode)->datamode;
+
+	if (datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY)
+		return vle_legacy_load_cluster_from_disk(m, lcn);
+
+	if (datamode == EROFS_INODE_FLAT_COMPRESSION)
+		return compacted_load_cluster_from_disk(m, lcn);
+
+	return -EINVAL;
+}
+
+static int vle_extent_lookback(struct z_erofs_maprecorder *m,
+			       unsigned int lookback_distance)
+{
+	struct erofs_vnode *const vi = EROFS_V(m->inode);
+	struct erofs_map_blocks *const map = m->map;
+	const unsigned int lclusterbits = vi->z_logical_clusterbits;
+	unsigned long lcn = m->lcn;
+	int err;
+
+	if (lcn < lookback_distance) {
+		DBG_BUGON(1);
+		return -EIO;
+	}
+
+	/* load extent head logical cluster if needed */
+	lcn -= lookback_distance;
+	err = vle_load_cluster_from_disk(m, lcn);
+	if (err)
+		return err;
+
+	switch (m->type) {
+	case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
+		return vle_extent_lookback(m, m->delta[0]);
+	case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
+		map->m_flags &= ~EROFS_MAP_ZIPPED;
+		/* fallthrough */
+	case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
+		map->m_la = (lcn << lclusterbits) | m->clusterofs;
+		break;
+	default:
+		errln("unknown type %u at lcn %lu of nid %llu",
+		      m->type, lcn, vi->nid);
+		DBG_BUGON(1);
+		return -EIO;
+	}
+	return 0;
+}
+
+int z_erofs_map_blocks_iter(struct inode *inode,
+			    struct erofs_map_blocks *map,
+			    int flags)
+{
+	struct erofs_vnode *const vi = EROFS_V(inode);
+	struct z_erofs_maprecorder m = {
+		.inode = inode,
+		.map = map,
+	};
+	int err = 0;
+	unsigned int lclusterbits, endoff;
+	unsigned long long ofs, end;
+
+	trace_z_erofs_map_blocks_iter_enter(inode, map, flags);
+
+	/* when trying to read beyond EOF, leave it unmapped */
+	if (unlikely(map->m_la >= inode->i_size)) {
+		map->m_llen = map->m_la + 1 - inode->i_size;
+		map->m_la = inode->i_size;
+		map->m_flags = 0;
+		goto out;
+	}
+
+	err = fill_inode_lazy(inode);
+	if (err)
+		goto out;
+
+	lclusterbits = vi->z_logical_clusterbits;
+	ofs = map->m_la;
+	m.lcn = ofs >> lclusterbits;
+	endoff = ofs & ((1 << lclusterbits) - 1);
+
+	err = vle_load_cluster_from_disk(&m, m.lcn);
+	if (err)
+		goto unmap_out;
+
+	map->m_flags = EROFS_MAP_ZIPPED;	/* by default, compressed */
+	end = (m.lcn + 1ULL) << lclusterbits;
+
+	switch (m.type) {
+	case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
+		if (endoff >= m.clusterofs)
+			map->m_flags &= ~EROFS_MAP_ZIPPED;
+		/* fallthrough */
+	case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
+		if (endoff >= m.clusterofs) {
+			map->m_la = (m.lcn << lclusterbits) | m.clusterofs;
+			break;
+		}
+		/* m.lcn should be >= 1 if endoff < m.clusterofs */
+		if (unlikely(!m.lcn)) {
+			errln("invalid logical cluster 0 at nid %llu",
+			      vi->nid);
+			err = -EIO;
+			goto unmap_out;
+		}
+		end = (m.lcn << lclusterbits) | m.clusterofs;
+		map->m_flags |= EROFS_MAP_FULL_MAPPED;
+		m.delta[0] = 1;
+		/* fallthrough */
+	case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
+		/* get the correspoinding first chunk */
+		err = vle_extent_lookback(&m, m.delta[0]);
+		if (unlikely(err))
+			goto unmap_out;
+		break;
+	default:
+		errln("unknown type %u at offset %llu of nid %llu",
+		      m.type, ofs, vi->nid);
+		err = -EIO;
+		goto unmap_out;
+	}
+
+	map->m_llen = end - map->m_la;
+	map->m_plen = 1 << lclusterbits;
+	map->m_pa = blknr_to_addr(m.pblk);
+	map->m_flags |= EROFS_MAP_MAPPED;
+
+unmap_out:
+	if (m.kaddr)
+		kunmap_atomic(m.kaddr);
+
+out:
+	debugln("%s, m_la %llu m_pa %llu m_llen %llu m_plen %llu m_flags 0%o",
+		__func__, map->m_la, map->m_pa,
+		map->m_llen, map->m_plen, map->m_flags);
+
+	trace_z_erofs_map_blocks_iter_exit(inode, map, flags, err);
+
+	/* aggressively BUG_ON iff CONFIG_EROFS_FS_DEBUG is on */
+	DBG_BUGON(err < 0 && err != -ENOMEM);
+	return err;
+}
+
diff --git a/include/trace/events/erofs.h b/include/trace/events/erofs.h
index 0c5847c54b60..bfb2da9c4eee 100644
--- a/include/trace/events/erofs.h
+++ b/include/trace/events/erofs.h
@@ -20,7 +20,8 @@
 
 #define show_mflags(flags) __print_flags(flags, "",	\
 	{ EROFS_MAP_MAPPED,	"M" },			\
-	{ EROFS_MAP_META,	"I" })
+	{ EROFS_MAP_META,	"I" },			\
+	{ EROFS_MAP_ZIPPED,	"Z" })
 
 TRACE_EVENT(erofs_lookup,
 
@@ -172,6 +173,13 @@ DEFINE_EVENT(erofs__map_blocks_enter, erofs_map_blocks_flatmode_enter,
 	TP_ARGS(inode, map, flags)
 );
 
+DEFINE_EVENT(erofs__map_blocks_enter, z_erofs_map_blocks_iter_enter,
+	TP_PROTO(struct inode *inode, struct erofs_map_blocks *map,
+		 unsigned int flags),
+
+	TP_ARGS(inode, map, flags)
+);
+
 DECLARE_EVENT_CLASS(erofs__map_blocks_exit,
 	TP_PROTO(struct inode *inode, struct erofs_map_blocks *map,
 		 unsigned int flags, int ret),
@@ -217,6 +225,13 @@ DEFINE_EVENT(erofs__map_blocks_exit, erofs_map_blocks_flatmode_exit,
 	TP_ARGS(inode, map, flags, ret)
 );
 
+DEFINE_EVENT(erofs__map_blocks_exit, z_erofs_map_blocks_iter_exit,
+	TP_PROTO(struct inode *inode, struct erofs_map_blocks *map,
+		 unsigned int flags, int ret),
+
+	TP_ARGS(inode, map, flags, ret)
+);
+
 TRACE_EVENT(erofs_destroy_inode,
 	TP_PROTO(struct inode *inode),
 
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v6 14/24] erofs: introduce superblock registration
  2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
                   ` (12 preceding siblings ...)
  2019-08-02 12:53 ` [PATCH v6 13/24] erofs: add compression indexes support Gao Xiang
@ 2019-08-02 12:53 ` Gao Xiang
  2019-08-02 12:53 ` [PATCH v6 15/24] erofs: introduce erofs shrinker Gao Xiang
                   ` (10 subsequent siblings)
  24 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-02 12:53 UTC (permalink / raw)
  To: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds
  Cc: linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei, Gao Xiang

In order to introducing shrinker solution for erofs,
let's manage all mounted erofs instances at first.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/Makefile   |  2 +-
 fs/erofs/internal.h | 13 +++++++++++++
 fs/erofs/super.c    |  9 +++++++++
 fs/erofs/utils.c    | 32 ++++++++++++++++++++++++++++++++
 4 files changed, 55 insertions(+), 1 deletion(-)
 create mode 100644 fs/erofs/utils.c

diff --git a/fs/erofs/Makefile b/fs/erofs/Makefile
index 481a966caf06..930770be124f 100644
--- a/fs/erofs/Makefile
+++ b/fs/erofs/Makefile
@@ -5,7 +5,7 @@ EROFS_VERSION = "1.0"
 ccflags-y += -DEROFS_VERSION=\"$(EROFS_VERSION)\"
 
 obj-$(CONFIG_EROFS_FS) += erofs.o
-erofs-objs := super.o inode.o data.o namei.o dir.o
+erofs-objs := super.o inode.o data.o namei.o dir.o utils.o
 erofs-$(CONFIG_EROFS_FS_XATTR) += xattr.o
 erofs-$(CONFIG_EROFS_FS_ZIP) += zmap.o
 
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index d3a703017233..082fa4727c80 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -61,6 +61,10 @@ typedef u64 erofs_off_t;
 typedef u32 erofs_blk_t;
 
 struct erofs_sb_info {
+#ifdef CONFIG_EROFS_FS_ZIP
+	/* list for all registered superblocks, mainly for shrinker */
+	struct list_head list;
+#endif	/* CONFIG_EROFS_FS_ZIP */
 	u32 blocks;
 	u32 meta_blkaddr;
 #ifdef CONFIG_EROFS_FS_XATTR
@@ -401,5 +405,14 @@ int erofs_namei(struct inode *dir, struct qstr *name,
 /* dir.c */
 extern const struct file_operations erofs_dir_fops;
 
+/* utils.c */
+#ifdef CONFIG_EROFS_FS_ZIP
+void erofs_shrinker_register(struct super_block *sb);
+void erofs_shrinker_unregister(struct super_block *sb);
+#else
+static inline void erofs_shrinker_register(struct super_block *sb) {}
+static inline void erofs_shrinker_unregister(struct super_block *sb) {}
+#endif	/* !CONFIG_EROFS_FS_ZIP */
+
 #endif	/* __EROFS_INTERNAL_H */
 
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 561ae6f7fe13..2eca3b25db75 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -354,6 +354,8 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
 	if (unlikely(!sb->s_root))
 		return -ENOMEM;
 
+	erofs_shrinker_register(sb);
+
 	if (!silent)
 		infoln("mounted on %s with opts: %s.", sb->s_id, (char *)data);
 	return 0;
@@ -385,6 +387,12 @@ static void erofs_kill_sb(struct super_block *sb)
 	sb->s_fs_info = NULL;
 }
 
+/* called when ->s_root is non-NULL */
+static void erofs_put_super(struct super_block *sb)
+{
+	erofs_shrinker_unregister(sb);
+}
+
 static struct file_system_type erofs_fs_type = {
 	.owner          = THIS_MODULE,
 	.name           = "erofs",
@@ -496,6 +504,7 @@ static int erofs_remount(struct super_block *sb, int *flags, char *data)
 }
 
 const struct super_operations erofs_sops = {
+	.put_super = erofs_put_super,
 	.alloc_inode = alloc_inode,
 	.free_inode = free_inode,
 	.statfs = erofs_statfs,
diff --git a/fs/erofs/utils.c b/fs/erofs/utils.c
new file mode 100644
index 000000000000..791b2df1f761
--- /dev/null
+++ b/fs/erofs/utils.c
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/fs/erofs/utils.c
+ *
+ * Copyright (C) 2018 HUAWEI, Inc.
+ *             http://www.huawei.com/
+ * Created by Gao Xiang <gaoxiang25@huawei.com>
+ */
+#include "internal.h"
+
+#ifdef CONFIG_EROFS_FS_ZIP
+/* protects the mounted 'erofs_sb_list' */
+static DEFINE_SPINLOCK(erofs_sb_list_lock);
+static LIST_HEAD(erofs_sb_list);
+
+void erofs_shrinker_register(struct super_block *sb)
+{
+	struct erofs_sb_info *sbi = EROFS_SB(sb);
+
+	spin_lock(&erofs_sb_list_lock);
+	list_add(&sbi->list, &erofs_sb_list);
+	spin_unlock(&erofs_sb_list_lock);
+}
+
+void erofs_shrinker_unregister(struct super_block *sb)
+{
+	spin_lock(&erofs_sb_list_lock);
+	list_del(&EROFS_SB(sb)->list);
+	spin_unlock(&erofs_sb_list_lock);
+}
+#endif	/* !CONFIG_EROFS_FS_ZIP */
+
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v6 15/24] erofs: introduce erofs shrinker
  2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
                   ` (13 preceding siblings ...)
  2019-08-02 12:53 ` [PATCH v6 14/24] erofs: introduce superblock registration Gao Xiang
@ 2019-08-02 12:53 ` Gao Xiang
  2019-08-02 12:53 ` [PATCH v6 16/24] erofs: introduce workstation for decompression Gao Xiang
                   ` (9 subsequent siblings)
  24 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-02 12:53 UTC (permalink / raw)
  To: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds
  Cc: linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei, Gao Xiang

This patch adds a dedicated shrinker targeting to free
unneeded memory consumed by a number of erofs in-memory
data structures.

Like F2FS and UBIFS, it also adds:
  - sbi->umount_mutex to avoid races on shrinker and put_super;
  - sbi->shrinker_run_no to not revisit recently scanned objects.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/internal.h |  7 ++++
 fs/erofs/super.c    |  6 +++
 fs/erofs/utils.c    | 93 ++++++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 105 insertions(+), 1 deletion(-)

diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 082fa4727c80..adc82993c8e9 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -64,6 +64,9 @@ struct erofs_sb_info {
 #ifdef CONFIG_EROFS_FS_ZIP
 	/* list for all registered superblocks, mainly for shrinker */
 	struct list_head list;
+	struct mutex umount_mutex;
+
+	unsigned int shrinker_run_no;
 #endif	/* CONFIG_EROFS_FS_ZIP */
 	u32 blocks;
 	u32 meta_blkaddr;
@@ -409,9 +412,13 @@ extern const struct file_operations erofs_dir_fops;
 #ifdef CONFIG_EROFS_FS_ZIP
 void erofs_shrinker_register(struct super_block *sb);
 void erofs_shrinker_unregister(struct super_block *sb);
+int __init erofs_init_shrinker(void);
+void erofs_exit_shrinker(void);
 #else
 static inline void erofs_shrinker_register(struct super_block *sb) {}
 static inline void erofs_shrinker_unregister(struct super_block *sb) {}
+static inline int erofs_init_shrinker(void) { return 0; }
+static inline void erofs_exit_shrinker(void) {}
 #endif	/* !CONFIG_EROFS_FS_ZIP */
 
 #endif	/* __EROFS_INTERNAL_H */
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 2eca3b25db75..09992cc3b2fd 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -413,6 +413,9 @@ static int __init erofs_module_init(void)
 	if (err)
 		goto icache_err;
 
+	err = erofs_init_shrinker();
+	if (err)
+		goto shrinker_err;
 	err = register_filesystem(&erofs_fs_type);
 	if (err)
 		goto fs_err;
@@ -421,6 +424,8 @@ static int __init erofs_module_init(void)
 	return 0;
 
 fs_err:
+	erofs_exit_shrinker();
+shrinker_err:
 	erofs_exit_inode_cache();
 icache_err:
 	return err;
@@ -429,6 +434,7 @@ static int __init erofs_module_init(void)
 static void __exit erofs_module_exit(void)
 {
 	unregister_filesystem(&erofs_fs_type);
+	erofs_exit_shrinker();
 	erofs_exit_inode_cache();
 	infoln("successfully finalize erofs");
 }
diff --git a/fs/erofs/utils.c b/fs/erofs/utils.c
index 791b2df1f761..cab7d77c4e59 100644
--- a/fs/erofs/utils.c
+++ b/fs/erofs/utils.c
@@ -9,6 +9,12 @@
 #include "internal.h"
 
 #ifdef CONFIG_EROFS_FS_ZIP
+/* global shrink count (for all mounted EROFS instances) */
+static atomic_long_t erofs_global_shrink_cnt;
+
+/* protected by 'erofs_sb_list_lock' */
+static unsigned int shrinker_run_no;
+
 /* protects the mounted 'erofs_sb_list' */
 static DEFINE_SPINLOCK(erofs_sb_list_lock);
 static LIST_HEAD(erofs_sb_list);
@@ -17,6 +23,8 @@ void erofs_shrinker_register(struct super_block *sb)
 {
 	struct erofs_sb_info *sbi = EROFS_SB(sb);
 
+	mutex_init(&sbi->umount_mutex);
+
 	spin_lock(&erofs_sb_list_lock);
 	list_add(&sbi->list, &erofs_sb_list);
 	spin_unlock(&erofs_sb_list_lock);
@@ -24,9 +32,92 @@ void erofs_shrinker_register(struct super_block *sb)
 
 void erofs_shrinker_unregister(struct super_block *sb)
 {
+	struct erofs_sb_info *const sbi = EROFS_SB(sb);
+
+	mutex_lock(&sbi->umount_mutex);
+	/* will add shrink final handler here */
+
+	spin_lock(&erofs_sb_list_lock);
+	list_del(&sbi->list);
+	spin_unlock(&erofs_sb_list_lock);
+	mutex_unlock(&sbi->umount_mutex);
+}
+
+static unsigned long erofs_shrink_count(struct shrinker *shrink,
+					struct shrink_control *sc)
+{
+	return atomic_long_read(&erofs_global_shrink_cnt);
+}
+
+static unsigned long erofs_shrink_scan(struct shrinker *shrink,
+				       struct shrink_control *sc)
+{
+	struct erofs_sb_info *sbi;
+	struct list_head *p;
+
+	unsigned long nr = sc->nr_to_scan;
+	unsigned int run_no;
+	unsigned long freed = 0;
+
 	spin_lock(&erofs_sb_list_lock);
-	list_del(&EROFS_SB(sb)->list);
+	do {
+		run_no = ++shrinker_run_no;
+	} while (run_no == 0);
+
+	/* Iterate over all mounted superblocks and try to shrink them */
+	p = erofs_sb_list.next;
+	while (p != &erofs_sb_list) {
+		sbi = list_entry(p, struct erofs_sb_info, list);
+
+		/*
+		 * We move the ones we do to the end of the list, so we stop
+		 * when we see one we have already done.
+		 */
+		if (sbi->shrinker_run_no == run_no)
+			break;
+
+		if (!mutex_trylock(&sbi->umount_mutex)) {
+			p = p->next;
+			continue;
+		}
+
+		spin_unlock(&erofs_sb_list_lock);
+		sbi->shrinker_run_no = run_no;
+
+		/* will add shrink handler here */
+
+		spin_lock(&erofs_sb_list_lock);
+		/* Get the next list element before we move this one */
+		p = p->next;
+
+		/*
+		 * Move this one to the end of the list to provide some
+		 * fairness.
+		 */
+		list_move_tail(&sbi->list, &erofs_sb_list);
+		mutex_unlock(&sbi->umount_mutex);
+
+		if (freed >= nr)
+			break;
+	}
 	spin_unlock(&erofs_sb_list_lock);
+	return freed;
+}
+
+static struct shrinker erofs_shrinker_info = {
+	.scan_objects = erofs_shrink_scan,
+	.count_objects = erofs_shrink_count,
+	.seeks = DEFAULT_SEEKS,
+};
+
+int __init erofs_init_shrinker(void)
+{
+	return register_shrinker(&erofs_shrinker_info);
+}
+
+void erofs_exit_shrinker(void)
+{
+	unregister_shrinker(&erofs_shrinker_info);
 }
 #endif	/* !CONFIG_EROFS_FS_ZIP */
 
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v6 16/24] erofs: introduce workstation for decompression
  2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
                   ` (14 preceding siblings ...)
  2019-08-02 12:53 ` [PATCH v6 15/24] erofs: introduce erofs shrinker Gao Xiang
@ 2019-08-02 12:53 ` Gao Xiang
  2019-08-02 12:53 ` [PATCH v6 17/24] erofs: introduce per-CPU buffers implementation Gao Xiang
                   ` (8 subsequent siblings)
  24 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-02 12:53 UTC (permalink / raw)
  To: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds
  Cc: linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei, Gao Xiang

This patch introduces another concept used by decompress
subsystem called 'workstation'. It can be seen as
a sparse array that stores pointers pointed to data
structures related to the corresponding physical clusters.

All lookups are protected by RCU read lock. Besides,
reference count and spin_lock are also introduced
to manage its lifetime and serialize all update
operations.

`workstation' is currently implemented on the in-kernel
radix tree approach for backward compatibility. With the
evolution of linux kernel, it will be migrated into
new XArray implementation in the future.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/internal.h |  80 +++++++++++++++++++++
 fs/erofs/super.c    |   4 ++
 fs/erofs/utils.c    | 166 +++++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 248 insertions(+), 2 deletions(-)

diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index adc82993c8e9..6f0384c3f07a 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -66,6 +66,9 @@ struct erofs_sb_info {
 	struct list_head list;
 	struct mutex umount_mutex;
 
+	/* the dedicated workstation for compression */
+	struct radix_tree_root workstn_tree;
+
 	unsigned int shrinker_run_no;
 #endif	/* CONFIG_EROFS_FS_ZIP */
 	u32 blocks;
@@ -151,6 +154,77 @@ static inline void *erofs_kmalloc(struct erofs_sb_info *sbi,
 #define set_opt(sbi, option)	((sbi)->mount_opt |= EROFS_MOUNT_##option)
 #define test_opt(sbi, option)	((sbi)->mount_opt & EROFS_MOUNT_##option)
 
+#ifdef CONFIG_EROFS_FS_ZIP
+#define EROFS_LOCKED_MAGIC     (INT_MIN | 0xE0F510CCL)
+
+/* basic unit of the workstation of a super_block */
+struct erofs_workgroup {
+	/* the workgroup index in the workstation */
+	pgoff_t index;
+
+	/* overall workgroup reference count */
+	atomic_t refcount;
+};
+
+#if defined(CONFIG_SMP)
+static inline bool erofs_workgroup_try_to_freeze(struct erofs_workgroup *grp,
+						 int val)
+{
+	preempt_disable();
+	if (val != atomic_cmpxchg(&grp->refcount, val, EROFS_LOCKED_MAGIC)) {
+		preempt_enable();
+		return false;
+	}
+	return true;
+}
+
+static inline void erofs_workgroup_unfreeze(struct erofs_workgroup *grp,
+					    int orig_val)
+{
+	/*
+	 * other observers should notice all modifications
+	 * in the freezing period.
+	 */
+	smp_mb();
+	atomic_set(&grp->refcount, orig_val);
+	preempt_enable();
+}
+
+static inline int erofs_wait_on_workgroup_freezed(struct erofs_workgroup *grp)
+{
+	return atomic_cond_read_relaxed(&grp->refcount,
+					VAL != EROFS_LOCKED_MAGIC);
+}
+#else
+static inline bool erofs_workgroup_try_to_freeze(struct erofs_workgroup *grp,
+						 int val)
+{
+	preempt_disable();
+	/* no need to spin on UP platforms, let's just disable preemption. */
+	if (val != atomic_read(&grp->refcount)) {
+		preempt_enable();
+		return false;
+	}
+	return true;
+}
+
+static inline void erofs_workgroup_unfreeze(struct erofs_workgroup *grp,
+					    int orig_val)
+{
+	preempt_enable();
+}
+
+static inline int erofs_wait_on_workgroup_freezed(struct erofs_workgroup *grp)
+{
+	int v = atomic_read(&grp->refcount);
+
+	/* workgroup is never freezed on uniprocessor systems */
+	DBG_BUGON(v == EROFS_LOCKED_MAGIC);
+	return v;
+}
+#endif	/* !CONFIG_SMP */
+#endif	/* !CONFIG_EROFS_FS_ZIP */
+
 /* we strictly follow PAGE_SIZE and no buffer head yet */
 #define LOG_BLOCK_SIZE		PAGE_SHIFT
 
@@ -410,6 +484,12 @@ extern const struct file_operations erofs_dir_fops;
 
 /* utils.c */
 #ifdef CONFIG_EROFS_FS_ZIP
+int erofs_workgroup_put(struct erofs_workgroup *grp);
+struct erofs_workgroup *erofs_find_workgroup(struct super_block *sb,
+					     pgoff_t index, bool *tag);
+int erofs_register_workgroup(struct super_block *sb,
+			     struct erofs_workgroup *grp, bool tag);
+static inline void erofs_workgroup_free_rcu(struct erofs_workgroup *grp) {}
 void erofs_shrinker_register(struct super_block *sb);
 void erofs_shrinker_unregister(struct super_block *sb);
 int __init erofs_init_shrinker(void);
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 09992cc3b2fd..ea8d065068fa 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -338,6 +338,10 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
 	else
 		sb->s_flags &= ~SB_POSIXACL;
 
+#ifdef CONFIG_EROFS_FS_ZIP
+	INIT_RADIX_TREE(&sbi->workstn_tree, GFP_ATOMIC);
+#endif
+
 	/* get the root inode */
 	inode = erofs_iget(sb, ROOT_NID(sbi), true);
 	if (IS_ERR(inode))
diff --git a/fs/erofs/utils.c b/fs/erofs/utils.c
index cab7d77c4e59..628178261056 100644
--- a/fs/erofs/utils.c
+++ b/fs/erofs/utils.c
@@ -7,11 +7,173 @@
  * Created by Gao Xiang <gaoxiang25@huawei.com>
  */
 #include "internal.h"
+#include <linux/pagevec.h>
 
 #ifdef CONFIG_EROFS_FS_ZIP
 /* global shrink count (for all mounted EROFS instances) */
 static atomic_long_t erofs_global_shrink_cnt;
 
+#define __erofs_workgroup_get(grp)	atomic_inc(&(grp)->refcount)
+#define __erofs_workgroup_put(grp)	atomic_dec(&(grp)->refcount)
+
+static int erofs_workgroup_get(struct erofs_workgroup *grp)
+{
+	int o;
+
+repeat:
+	o = erofs_wait_on_workgroup_freezed(grp);
+	if (unlikely(o <= 0))
+		return -1;
+
+	if (unlikely(atomic_cmpxchg(&grp->refcount, o, o + 1) != o))
+		goto repeat;
+
+	/* decrease refcount paired by erofs_workgroup_put */
+	if (unlikely(o == 1))
+		atomic_long_dec(&erofs_global_shrink_cnt);
+	return 0;
+}
+
+struct erofs_workgroup *erofs_find_workgroup(struct super_block *sb,
+					     pgoff_t index, bool *tag)
+{
+	struct erofs_sb_info *sbi = EROFS_SB(sb);
+	struct erofs_workgroup *grp;
+
+repeat:
+	rcu_read_lock();
+	grp = radix_tree_lookup(&sbi->workstn_tree, index);
+	if (grp) {
+		*tag = xa_pointer_tag(grp);
+		grp = xa_untag_pointer(grp);
+
+		if (erofs_workgroup_get(grp)) {
+			/* prefer to relax rcu read side */
+			rcu_read_unlock();
+			goto repeat;
+		}
+
+		DBG_BUGON(index != grp->index);
+	}
+	rcu_read_unlock();
+	return grp;
+}
+
+int erofs_register_workgroup(struct super_block *sb,
+			     struct erofs_workgroup *grp,
+			     bool tag)
+{
+	struct erofs_sb_info *sbi;
+	int err;
+
+	/* grp shouldn't be broken or used before */
+	if (unlikely(atomic_read(&grp->refcount) != 1)) {
+		DBG_BUGON(1);
+		return -EINVAL;
+	}
+
+	err = radix_tree_preload(GFP_NOFS);
+	if (err)
+		return err;
+
+	sbi = EROFS_SB(sb);
+	xa_lock(&sbi->workstn_tree);
+
+	grp = xa_tag_pointer(grp, tag);
+
+	/*
+	 * Bump up reference count before making this workgroup
+	 * visible to other users in order to avoid potential UAF
+	 * without serialized by workstn_lock.
+	 */
+	__erofs_workgroup_get(grp);
+
+	err = radix_tree_insert(&sbi->workstn_tree, grp->index, grp);
+	if (unlikely(err))
+		/*
+		 * it's safe to decrease since the workgroup isn't visible
+		 * and refcount >= 2 (cannot be freezed).
+		 */
+		__erofs_workgroup_put(grp);
+
+	xa_unlock(&sbi->workstn_tree);
+	radix_tree_preload_end();
+	return err;
+}
+
+static void  __erofs_workgroup_free(struct erofs_workgroup *grp)
+{
+	atomic_long_dec(&erofs_global_shrink_cnt);
+	erofs_workgroup_free_rcu(grp);
+}
+
+int erofs_workgroup_put(struct erofs_workgroup *grp)
+{
+	int count = atomic_dec_return(&grp->refcount);
+
+	if (count == 1)
+		atomic_long_inc(&erofs_global_shrink_cnt);
+	else if (!count)
+		__erofs_workgroup_free(grp);
+	return count;
+}
+
+/* for nocache case, no customized reclaim path at all */
+static bool erofs_try_to_release_workgroup(struct erofs_sb_info *sbi,
+					   struct erofs_workgroup *grp,
+					   bool cleanup)
+{
+	int cnt = atomic_read(&grp->refcount);
+
+	DBG_BUGON(cnt <= 0);
+	DBG_BUGON(cleanup && cnt != 1);
+
+	if (cnt > 1)
+		return false;
+
+	DBG_BUGON(xa_untag_pointer(radix_tree_delete(&sbi->workstn_tree,
+						     grp->index)) != grp);
+
+	/* (rarely) could be grabbed again when freeing */
+	erofs_workgroup_put(grp);
+	return true;
+}
+
+static unsigned long erofs_shrink_workstation(struct erofs_sb_info *sbi,
+					      unsigned long nr_shrink,
+					      bool cleanup)
+{
+	pgoff_t first_index = 0;
+	void *batch[PAGEVEC_SIZE];
+	unsigned int freed = 0;
+
+	int i, found;
+repeat:
+	xa_lock(&sbi->workstn_tree);
+
+	found = radix_tree_gang_lookup(&sbi->workstn_tree,
+				       batch, first_index, PAGEVEC_SIZE);
+
+	for (i = 0; i < found; ++i) {
+		struct erofs_workgroup *grp = xa_untag_pointer(batch[i]);
+
+		first_index = grp->index + 1;
+
+		/* try to shrink each valid workgroup */
+		if (!erofs_try_to_release_workgroup(sbi, grp, cleanup))
+			continue;
+
+		++freed;
+		if (unlikely(!--nr_shrink))
+			break;
+	}
+	xa_unlock(&sbi->workstn_tree);
+
+	if (i && nr_shrink)
+		goto repeat;
+	return freed;
+}
+
 /* protected by 'erofs_sb_list_lock' */
 static unsigned int shrinker_run_no;
 
@@ -35,7 +197,7 @@ void erofs_shrinker_unregister(struct super_block *sb)
 	struct erofs_sb_info *const sbi = EROFS_SB(sb);
 
 	mutex_lock(&sbi->umount_mutex);
-	/* will add shrink final handler here */
+	erofs_shrink_workstation(sbi, ~0UL, true);
 
 	spin_lock(&erofs_sb_list_lock);
 	list_del(&sbi->list);
@@ -84,7 +246,7 @@ static unsigned long erofs_shrink_scan(struct shrinker *shrink,
 		spin_unlock(&erofs_sb_list_lock);
 		sbi->shrinker_run_no = run_no;
 
-		/* will add shrink handler here */
+		freed += erofs_shrink_workstation(sbi, nr, false);
 
 		spin_lock(&erofs_sb_list_lock);
 		/* Get the next list element before we move this one */
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v6 17/24] erofs: introduce per-CPU buffers implementation
  2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
                   ` (15 preceding siblings ...)
  2019-08-02 12:53 ` [PATCH v6 16/24] erofs: introduce workstation for decompression Gao Xiang
@ 2019-08-02 12:53 ` Gao Xiang
  2019-08-02 12:53 ` [PATCH v6 18/24] erofs: introduce pagevec for decompression subsystem Gao Xiang
                   ` (7 subsequent siblings)
  24 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-02 12:53 UTC (permalink / raw)
  To: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds
  Cc: linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei, Gao Xiang

This patch introduces per-CPU buffers in order for
the upcoming generic decompression framework to use.

Note that I tried to use in-kernel per-CPU buffer or
per-CPU page approaches to clean up further, however
noticeable performanace regression (about 2% for
sequential read) was observed.

Let's leave it as-is for now.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/Kconfig    | 14 ++++++++++++++
 fs/erofs/internal.h | 21 +++++++++++++++++++++
 fs/erofs/utils.c    | 12 ++++++++++++
 3 files changed, 47 insertions(+)

diff --git a/fs/erofs/Kconfig b/fs/erofs/Kconfig
index a475fbebb831..5f8787c0cf89 100644
--- a/fs/erofs/Kconfig
+++ b/fs/erofs/Kconfig
@@ -81,3 +81,17 @@ config EROFS_FS_ZIP
 
 	  If you don't want to enable compression feature, say N.
 
+config EROFS_FS_CLUSTER_PAGE_LIMIT
+	int "EROFS Cluster Pages Hard Limit"
+	depends on EROFS_FS_ZIP
+	range 1 256
+	default "1"
+	help
+	  Indicates maximum # of pages of a compressed
+	  physical cluster.
+
+	  For example, if files in a image were compressed
+	  into 8k-unit, hard limit should not be configured
+	  less than 2. Otherwise, the image will be refused
+	  to mount on this kernel.
+
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 6f0384c3f07a..19694886dda9 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -223,6 +223,12 @@ static inline int erofs_wait_on_workgroup_freezed(struct erofs_workgroup *grp)
 	return v;
 }
 #endif	/* !CONFIG_SMP */
+
+/* hard limit of pages per compressed cluster */
+#define Z_EROFS_CLUSTER_MAX_PAGES       (CONFIG_EROFS_FS_CLUSTER_PAGE_LIMIT)
+#define EROFS_PCPUBUF_NR_PAGES          Z_EROFS_CLUSTER_MAX_PAGES
+#else
+#define EROFS_PCPUBUF_NR_PAGES          0
 #endif	/* !CONFIG_EROFS_FS_ZIP */
 
 /* we strictly follow PAGE_SIZE and no buffer head yet */
@@ -483,6 +489,21 @@ int erofs_namei(struct inode *dir, struct qstr *name,
 extern const struct file_operations erofs_dir_fops;
 
 /* utils.c */
+#if (EROFS_PCPUBUF_NR_PAGES > 0)
+void *erofs_get_pcpubuf(unsigned int pagenr);
+#define erofs_put_pcpubuf(buf) do { \
+	(void)&(buf);	\
+	preempt_enable();	\
+} while (0)
+#else
+static inline void *erofs_get_pcpubuf(unsigned int pagenr)
+{
+	return ERR_PTR(-ENOTSUPP);
+}
+
+#define erofs_put_pcpubuf(buf) do {} while (0)
+#endif
+
 #ifdef CONFIG_EROFS_FS_ZIP
 int erofs_workgroup_put(struct erofs_workgroup *grp);
 struct erofs_workgroup *erofs_find_workgroup(struct super_block *sb,
diff --git a/fs/erofs/utils.c b/fs/erofs/utils.c
index 628178261056..f3eed9af24d6 100644
--- a/fs/erofs/utils.c
+++ b/fs/erofs/utils.c
@@ -9,6 +9,18 @@
 #include "internal.h"
 #include <linux/pagevec.h>
 
+#if (EROFS_PCPUBUF_NR_PAGES > 0)
+static struct {
+	u8 data[PAGE_SIZE * EROFS_PCPUBUF_NR_PAGES];
+} ____cacheline_aligned_in_smp erofs_pcpubuf[NR_CPUS];
+
+void *erofs_get_pcpubuf(unsigned int pagenr)
+{
+	preempt_disable();
+	return &erofs_pcpubuf[smp_processor_id()].data[pagenr * PAGE_SIZE];
+}
+#endif
+
 #ifdef CONFIG_EROFS_FS_ZIP
 /* global shrink count (for all mounted EROFS instances) */
 static atomic_long_t erofs_global_shrink_cnt;
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v6 18/24] erofs: introduce pagevec for decompression subsystem
  2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
                   ` (16 preceding siblings ...)
  2019-08-02 12:53 ` [PATCH v6 17/24] erofs: introduce per-CPU buffers implementation Gao Xiang
@ 2019-08-02 12:53 ` Gao Xiang
  2019-08-02 12:53 ` [PATCH v6 19/24] erofs: add erofs_allocpage() Gao Xiang
                   ` (6 subsequent siblings)
  24 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-02 12:53 UTC (permalink / raw)
  To: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds
  Cc: linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei, Gao Xiang

For each physical cluster, there is a straight-forward
way of allocating a fixed or variable-sized array to
record the corresponding file pages for its decompression
if we decide to decompress these pages asynchronously
(eg. read-ahead case), however it will take variable-sized
on-heap memory compared with traditional uncompressed
filesystems.

This patch introduces a pagevec solution to reuse some
allocated file page in the time-sharing approach to store
parts of the array itself in order to minimize the extra
memory overhead, thus only a small-sized constant array
used for booting the whole array itself up will be needed.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/zpvec.h | 159 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 159 insertions(+)
 create mode 100644 fs/erofs/zpvec.h

diff --git a/fs/erofs/zpvec.h b/fs/erofs/zpvec.h
new file mode 100644
index 000000000000..bb7689e67836
--- /dev/null
+++ b/fs/erofs/zpvec.h
@@ -0,0 +1,159 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * linux/fs/erofs/zpvec.h
+ *
+ * Copyright (C) 2018 HUAWEI, Inc.
+ *             http://www.huawei.com/
+ * Created by Gao Xiang <gaoxiang25@huawei.com>
+ */
+#ifndef __EROFS_FS_ZPVEC_H
+#define __EROFS_FS_ZPVEC_H
+
+#include "tagptr.h"
+
+/* page type in pagevec for decompress subsystem */
+enum z_erofs_page_type {
+	/* including Z_EROFS_VLE_PAGE_TAIL_EXCLUSIVE */
+	Z_EROFS_PAGE_TYPE_EXCLUSIVE,
+
+	Z_EROFS_VLE_PAGE_TYPE_TAIL_SHARED,
+
+	Z_EROFS_VLE_PAGE_TYPE_HEAD,
+	Z_EROFS_VLE_PAGE_TYPE_MAX
+};
+
+extern void __compiletime_error("Z_EROFS_PAGE_TYPE_EXCLUSIVE != 0")
+	__bad_page_type_exclusive(void);
+
+/* pagevec tagged pointer */
+typedef tagptr2_t	erofs_vtptr_t;
+
+/* pagevec collector */
+struct z_erofs_pagevec_ctor {
+	struct page *curr, *next;
+	erofs_vtptr_t *pages;
+
+	unsigned int nr, index;
+};
+
+static inline void z_erofs_pagevec_ctor_exit(struct z_erofs_pagevec_ctor *ctor,
+					     bool atomic)
+{
+	if (!ctor->curr)
+		return;
+
+	if (atomic)
+		kunmap_atomic(ctor->pages);
+	else
+		kunmap(ctor->curr);
+}
+
+static inline struct page *
+z_erofs_pagevec_ctor_next_page(struct z_erofs_pagevec_ctor *ctor,
+			       unsigned int nr)
+{
+	unsigned int index;
+
+	/* keep away from occupied pages */
+	if (ctor->next)
+		return ctor->next;
+
+	for (index = 0; index < nr; ++index) {
+		const erofs_vtptr_t t = ctor->pages[index];
+		const unsigned int tags = tagptr_unfold_tags(t);
+
+		if (tags == Z_EROFS_PAGE_TYPE_EXCLUSIVE)
+			return tagptr_unfold_ptr(t);
+	}
+	DBG_BUGON(nr >= ctor->nr);
+	return NULL;
+}
+
+static inline void
+z_erofs_pagevec_ctor_pagedown(struct z_erofs_pagevec_ctor *ctor,
+			      bool atomic)
+{
+	struct page *next = z_erofs_pagevec_ctor_next_page(ctor, ctor->nr);
+
+	z_erofs_pagevec_ctor_exit(ctor, atomic);
+
+	ctor->curr = next;
+	ctor->next = NULL;
+	ctor->pages = atomic ?
+		kmap_atomic(ctor->curr) : kmap(ctor->curr);
+
+	ctor->nr = PAGE_SIZE / sizeof(struct page *);
+	ctor->index = 0;
+}
+
+static inline void z_erofs_pagevec_ctor_init(struct z_erofs_pagevec_ctor *ctor,
+					     unsigned int nr,
+					     erofs_vtptr_t *pages,
+					     unsigned int i)
+{
+	ctor->nr = nr;
+	ctor->curr = ctor->next = NULL;
+	ctor->pages = pages;
+
+	if (i >= nr) {
+		i -= nr;
+		z_erofs_pagevec_ctor_pagedown(ctor, false);
+		while (i > ctor->nr) {
+			i -= ctor->nr;
+			z_erofs_pagevec_ctor_pagedown(ctor, false);
+		}
+	}
+	ctor->next = z_erofs_pagevec_ctor_next_page(ctor, i);
+	ctor->index = i;
+}
+
+static inline bool z_erofs_pagevec_enqueue(struct z_erofs_pagevec_ctor *ctor,
+					   struct page *page,
+					   enum z_erofs_page_type type,
+					   bool *occupied)
+{
+	*occupied = false;
+	if (unlikely(!ctor->next && type))
+		if (ctor->index + 1 == ctor->nr)
+			return false;
+
+	if (unlikely(ctor->index >= ctor->nr))
+		z_erofs_pagevec_ctor_pagedown(ctor, false);
+
+	/* exclusive page type must be 0 */
+	if (Z_EROFS_PAGE_TYPE_EXCLUSIVE != (uintptr_t)NULL)
+		__bad_page_type_exclusive();
+
+	/* should remind that collector->next never equal to 1, 2 */
+	if (type == (uintptr_t)ctor->next) {
+		ctor->next = page;
+		*occupied = true;
+	}
+	ctor->pages[ctor->index++] = tagptr_fold(erofs_vtptr_t, page, type);
+	return true;
+}
+
+static inline struct page *
+z_erofs_pagevec_dequeue(struct z_erofs_pagevec_ctor *ctor,
+			enum z_erofs_page_type *type)
+{
+	erofs_vtptr_t t;
+
+	if (unlikely(ctor->index >= ctor->nr)) {
+		DBG_BUGON(!ctor->next);
+		z_erofs_pagevec_ctor_pagedown(ctor, true);
+	}
+
+	t = ctor->pages[ctor->index];
+
+	*type = tagptr_unfold_tags(t);
+
+	/* should remind that collector->next never equal to 1, 2 */
+	if (*type == (uintptr_t)ctor->next)
+		ctor->next = tagptr_unfold_ptr(t);
+
+	ctor->pages[ctor->index++] = tagptr_fold(erofs_vtptr_t, NULL, 0);
+	return tagptr_unfold_ptr(t);
+}
+#endif
+
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v6 19/24] erofs: add erofs_allocpage()
  2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
                   ` (17 preceding siblings ...)
  2019-08-02 12:53 ` [PATCH v6 18/24] erofs: introduce pagevec for decompression subsystem Gao Xiang
@ 2019-08-02 12:53 ` Gao Xiang
  2019-08-02 12:53 ` [PATCH v6 20/24] erofs: introduce generic decompression backend Gao Xiang
                   ` (5 subsequent siblings)
  24 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-02 12:53 UTC (permalink / raw)
  To: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds
  Cc: linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei, Gao Xiang

This patch introduces an temporary _on-stack_ page
pool to reuse the freed page directly as much as
it can for better performance and release all pages
at a time, it also slightly reduces the possibility of
the potential memory allocation failure.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/internal.h |  2 ++
 fs/erofs/utils.c    | 14 ++++++++++++++
 2 files changed, 16 insertions(+)

diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 19694886dda9..1a322304560f 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -489,6 +489,8 @@ int erofs_namei(struct inode *dir, struct qstr *name,
 extern const struct file_operations erofs_dir_fops;
 
 /* utils.c */
+struct page *erofs_allocpage(struct list_head *pool, gfp_t gfp, bool nofail);
+
 #if (EROFS_PCPUBUF_NR_PAGES > 0)
 void *erofs_get_pcpubuf(unsigned int pagenr);
 #define erofs_put_pcpubuf(buf) do { \
diff --git a/fs/erofs/utils.c b/fs/erofs/utils.c
index f3eed9af24d6..ae6362abed67 100644
--- a/fs/erofs/utils.c
+++ b/fs/erofs/utils.c
@@ -9,6 +9,20 @@
 #include "internal.h"
 #include <linux/pagevec.h>
 
+struct page *erofs_allocpage(struct list_head *pool, gfp_t gfp, bool nofail)
+{
+	struct page *page;
+
+	if (!list_empty(pool)) {
+		page = lru_to_page(pool);
+		DBG_BUGON(page_ref_count(page) != 1);
+		list_del(&page->lru);
+	} else {
+		page = alloc_pages(gfp | (nofail ? __GFP_NOFAIL : 0), 0);
+	}
+	return page;
+}
+
 #if (EROFS_PCPUBUF_NR_PAGES > 0)
 static struct {
 	u8 data[PAGE_SIZE * EROFS_PCPUBUF_NR_PAGES];
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v6 20/24] erofs: introduce generic decompression backend
  2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
                   ` (18 preceding siblings ...)
  2019-08-02 12:53 ` [PATCH v6 19/24] erofs: add erofs_allocpage() Gao Xiang
@ 2019-08-02 12:53 ` Gao Xiang
  2019-08-02 12:53 ` [PATCH v6 21/24] erofs: introduce LZ4 decompression inplace Gao Xiang
                   ` (4 subsequent siblings)
  24 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-02 12:53 UTC (permalink / raw)
  To: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds
  Cc: linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei, Gao Xiang

This patch adds decompression backend to EROFS, which
supports uncompressed and LZ4 compressed data.

For compressed data, it uses the following strategy:
1) If outputsize is very small (totally less than a threshold),
   decompress to the per-CPU buffer and do memcpy directly
   in order to avoid vmap() overhead;
2) Otherwise it will fill bounced pages if needed and vmap
   all output pages into a continuous virtual memory area,
   memcpy compressed data to the per-CPU buffer for inplace
   I/O [1] and decompress.

Since LZ4 is a lz77-based algorithm which has a dynamically
populated ("sliding window") dictionary and the maximum
lookback distance is 65535. Therefore the number of bounced
pages could be limited by erofs based on this property.

[1] `LZ4 decompression inplace' will eliminate the extra memcpy
    if iend - oend margin is safe enough, see the following patch.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/Makefile       |   2 +-
 fs/erofs/compress.h     |  62 ++++++++
 fs/erofs/decompressor.c | 332 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 395 insertions(+), 1 deletion(-)
 create mode 100644 fs/erofs/compress.h
 create mode 100644 fs/erofs/decompressor.c

diff --git a/fs/erofs/Makefile b/fs/erofs/Makefile
index 930770be124f..5594abca6f95 100644
--- a/fs/erofs/Makefile
+++ b/fs/erofs/Makefile
@@ -7,5 +7,5 @@ ccflags-y += -DEROFS_VERSION=\"$(EROFS_VERSION)\"
 obj-$(CONFIG_EROFS_FS) += erofs.o
 erofs-objs := super.o inode.o data.o namei.o dir.o utils.o
 erofs-$(CONFIG_EROFS_FS_XATTR) += xattr.o
-erofs-$(CONFIG_EROFS_FS_ZIP) += zmap.o
+erofs-$(CONFIG_EROFS_FS_ZIP) += decompressor.o zmap.o
 
diff --git a/fs/erofs/compress.h b/fs/erofs/compress.h
new file mode 100644
index 000000000000..57035b7646ef
--- /dev/null
+++ b/fs/erofs/compress.h
@@ -0,0 +1,62 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * linux/fs/erofs/compress.h
+ *
+ * Copyright (C) 2019 HUAWEI, Inc.
+ *             http://www.huawei.com/
+ * Created by Gao Xiang <gaoxiang25@huawei.com>
+ */
+#ifndef __EROFS_FS_COMPRESS_H
+#define __EROFS_FS_COMPRESS_H
+
+#include "internal.h"
+
+enum {
+	Z_EROFS_COMPRESSION_SHIFTED = Z_EROFS_COMPRESSION_MAX,
+	Z_EROFS_COMPRESSION_RUNTIME_MAX
+};
+
+struct z_erofs_decompress_req {
+	struct super_block *sb;
+	struct page **in, **out;
+
+	unsigned short pageofs_out;
+	unsigned int inputsize, outputsize;
+
+	/* indicate the algorithm will be used for decompression */
+	unsigned int alg;
+	bool inplace_io, partial_decoding;
+};
+
+/*
+ * - 0x5A110C8D ('sallocated', Z_EROFS_MAPPING_STAGING) -
+ * used to mark temporary allocated pages from other
+ * file/cached pages and NULL mapping pages.
+ */
+#define Z_EROFS_MAPPING_STAGING         ((void *)0x5A110C8D)
+
+/* check if a page is marked as staging */
+static inline bool z_erofs_page_is_staging(struct page *page)
+{
+	return page->mapping == Z_EROFS_MAPPING_STAGING;
+}
+
+static inline bool z_erofs_put_stagingpage(struct list_head *pagepool,
+					   struct page *page)
+{
+	if (!z_erofs_page_is_staging(page))
+		return false;
+
+	/* staging pages should not be used by others at the same time */
+	if (page_ref_count(page) > 1)
+		put_page(page);
+	else
+		list_add(&page->lru, pagepool);
+	return true;
+}
+
+int z_erofs_decompress(struct z_erofs_decompress_req *rq,
+		       struct list_head *pagepool);
+
+#endif
+
diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
new file mode 100644
index 000000000000..244afb29907d
--- /dev/null
+++ b/fs/erofs/decompressor.c
@@ -0,0 +1,332 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/fs/erofs/decompressor.c
+ *
+ * Copyright (C) 2019 HUAWEI, Inc.
+ *             http://www.huawei.com/
+ * Created by Gao Xiang <gaoxiang25@huawei.com>
+ */
+#include "compress.h"
+#include <linux/module.h>
+#include <linux/lz4.h>
+
+#ifndef LZ4_DISTANCE_MAX	/* history window size */
+#define LZ4_DISTANCE_MAX 65535	/* set to maximum value by default */
+#endif
+
+#define LZ4_MAX_DISTANCE_PAGES	(DIV_ROUND_UP(LZ4_DISTANCE_MAX, PAGE_SIZE) + 1)
+
+struct z_erofs_decompressor {
+	/*
+	 * if destpages have sparsed pages, fill them with bounce pages.
+	 * it also check whether destpages indicate continuous physical memory.
+	 */
+	int (*prepare_destpages)(struct z_erofs_decompress_req *rq,
+				 struct list_head *pagepool);
+	int (*decompress)(struct z_erofs_decompress_req *rq, u8 *out);
+	char *name;
+};
+
+static bool use_vmap;
+module_param(use_vmap, bool, 0444);
+MODULE_PARM_DESC(use_vmap, "Use vmap() instead of vm_map_ram() (default 0)");
+
+static int lz4_prepare_destpages(struct z_erofs_decompress_req *rq,
+				 struct list_head *pagepool)
+{
+	const unsigned int nr =
+		PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
+	struct page *availables[LZ4_MAX_DISTANCE_PAGES] = { NULL };
+	unsigned long bounced[DIV_ROUND_UP(LZ4_MAX_DISTANCE_PAGES,
+					   BITS_PER_LONG)] = { 0 };
+	void *kaddr = NULL;
+	unsigned int i, j, top;
+
+	top = 0;
+	for (i = j = 0; i < nr; ++i, ++j) {
+		struct page *const page = rq->out[i];
+		struct page *victim;
+
+		if (j >= LZ4_MAX_DISTANCE_PAGES)
+			j = 0;
+
+		/* 'valid' bounced can only be tested after a complete round */
+		if (test_bit(j, bounced)) {
+			DBG_BUGON(i < LZ4_MAX_DISTANCE_PAGES);
+			DBG_BUGON(top >= LZ4_MAX_DISTANCE_PAGES);
+			availables[top++] = rq->out[i - LZ4_MAX_DISTANCE_PAGES];
+		}
+
+		if (page) {
+			__clear_bit(j, bounced);
+			if (kaddr) {
+				if (kaddr + PAGE_SIZE == page_address(page))
+					kaddr += PAGE_SIZE;
+				else
+					kaddr = NULL;
+			} else if (!i) {
+				kaddr = page_address(page);
+			}
+			continue;
+		}
+		kaddr = NULL;
+		__set_bit(j, bounced);
+
+		if (top) {
+			victim = availables[--top];
+			get_page(victim);
+		} else {
+			victim = erofs_allocpage(pagepool, GFP_KERNEL, false);
+			if (unlikely(!victim))
+				return -ENOMEM;
+			victim->mapping = Z_EROFS_MAPPING_STAGING;
+		}
+		rq->out[i] = victim;
+	}
+	return kaddr ? 1 : 0;
+}
+
+static void *generic_copy_inplace_data(struct z_erofs_decompress_req *rq,
+				       u8 *src, unsigned int pageofs_in)
+{
+	/*
+	 * if in-place decompression is ongoing, those decompressed
+	 * pages should be copied in order to avoid being overlapped.
+	 */
+	struct page **in = rq->in;
+	u8 *const tmp = erofs_get_pcpubuf(0);
+	u8 *tmpp = tmp;
+	unsigned int inlen = rq->inputsize - pageofs_in;
+	unsigned int count = min_t(uint, inlen, PAGE_SIZE - pageofs_in);
+
+	while (tmpp < tmp + inlen) {
+		if (!src)
+			src = kmap_atomic(*in);
+		memcpy(tmpp, src + pageofs_in, count);
+		kunmap_atomic(src);
+		src = NULL;
+		tmpp += count;
+		pageofs_in = 0;
+		count = PAGE_SIZE;
+		++in;
+	}
+	return tmp;
+}
+
+static int lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out)
+{
+	unsigned int inputmargin, inlen;
+	u8 *src;
+	bool copied;
+	int ret;
+
+	if (rq->inputsize > PAGE_SIZE)
+		return -ENOTSUPP;
+
+	src = kmap_atomic(*rq->in);
+	inputmargin = 0;
+
+	copied = false;
+	inlen = rq->inputsize - inputmargin;
+	if (rq->inplace_io) {
+		src = generic_copy_inplace_data(rq, src, inputmargin);
+		inputmargin = 0;
+		copied = true;
+	}
+
+	ret = LZ4_decompress_safe_partial(src + inputmargin, out,
+					  inlen, rq->outputsize,
+					  rq->outputsize);
+	if (ret < 0) {
+		errln("%s, failed to decompress, in[%p, %u, %u] out[%p, %u]",
+		      __func__, src + inputmargin, inlen, inputmargin,
+		      out, rq->outputsize);
+		WARN_ON(1);
+		print_hex_dump(KERN_DEBUG, "[ in]: ", DUMP_PREFIX_OFFSET,
+			       16, 1, src + inputmargin, inlen, true);
+		print_hex_dump(KERN_DEBUG, "[out]: ", DUMP_PREFIX_OFFSET,
+			       16, 1, out, rq->outputsize, true);
+		ret = -EIO;
+	}
+
+	if (copied)
+		erofs_put_pcpubuf(src);
+	else
+		kunmap_atomic(src);
+	return ret;
+}
+
+static struct z_erofs_decompressor decompressors[] = {
+	[Z_EROFS_COMPRESSION_SHIFTED] = {
+		.name = "shifted"
+	},
+	[Z_EROFS_COMPRESSION_LZ4] = {
+		.prepare_destpages = lz4_prepare_destpages,
+		.decompress = lz4_decompress,
+		.name = "lz4"
+	},
+};
+
+static void copy_from_pcpubuf(struct page **out, const char *dst,
+			      unsigned short pageofs_out,
+			      unsigned int outputsize)
+{
+	const char *end = dst + outputsize;
+	const unsigned int righthalf = PAGE_SIZE - pageofs_out;
+	const char *cur = dst - pageofs_out;
+
+	while (cur < end) {
+		struct page *const page = *out++;
+
+		if (page) {
+			char *buf = kmap_atomic(page);
+
+			if (cur >= dst) {
+				memcpy(buf, cur, min_t(uint, PAGE_SIZE,
+						       end - cur));
+			} else {
+				memcpy(buf + pageofs_out, cur + pageofs_out,
+				       min_t(uint, righthalf, end - cur));
+			}
+			kunmap_atomic(buf);
+		}
+		cur += PAGE_SIZE;
+	}
+}
+
+static void *erofs_vmap(struct page **pages, unsigned int count)
+{
+	int i = 0;
+
+	if (use_vmap)
+		return vmap(pages, count, VM_MAP, PAGE_KERNEL);
+
+	while (1) {
+		void *addr = vm_map_ram(pages, count, -1, PAGE_KERNEL);
+
+		/* retry two more times (totally 3 times) */
+		if (addr || ++i >= 3)
+			return addr;
+		vm_unmap_aliases();
+	}
+	return NULL;
+}
+
+static void erofs_vunmap(const void *mem, unsigned int count)
+{
+	if (!use_vmap)
+		vm_unmap_ram(mem, count);
+	else
+		vunmap(mem);
+}
+
+static int decompress_generic(struct z_erofs_decompress_req *rq,
+			      struct list_head *pagepool)
+{
+	const unsigned int nrpages_out =
+		PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
+	const struct z_erofs_decompressor *alg = decompressors + rq->alg;
+	unsigned int dst_maptype;
+	void *dst;
+	int ret;
+
+	if (nrpages_out == 1 && !rq->inplace_io) {
+		DBG_BUGON(!*rq->out);
+		dst = kmap_atomic(*rq->out);
+		dst_maptype = 0;
+		goto dstmap_out;
+	}
+
+	/*
+	 * For the case of small output size (especially much less
+	 * than PAGE_SIZE), memcpy the decompressed data rather than
+	 * compressed data is preferred.
+	 */
+	if (rq->outputsize <= PAGE_SIZE * 7 / 8) {
+		dst = erofs_get_pcpubuf(0);
+		if (IS_ERR(dst))
+			return PTR_ERR(dst);
+
+		rq->inplace_io = false;
+		ret = alg->decompress(rq, dst);
+		if (!ret)
+			copy_from_pcpubuf(rq->out, dst, rq->pageofs_out,
+					  rq->outputsize);
+
+		erofs_put_pcpubuf(dst);
+		return ret;
+	}
+
+	ret = alg->prepare_destpages(rq, pagepool);
+	if (ret < 0) {
+		return ret;
+	} else if (ret) {
+		dst = page_address(*rq->out);
+		dst_maptype = 1;
+		goto dstmap_out;
+	}
+
+	dst = erofs_vmap(rq->out, nrpages_out);
+	if (!dst)
+		return -ENOMEM;
+	dst_maptype = 2;
+
+dstmap_out:
+	ret = alg->decompress(rq, dst + rq->pageofs_out);
+
+	if (!dst_maptype)
+		kunmap_atomic(dst);
+	else if (dst_maptype == 2)
+		erofs_vunmap(dst, nrpages_out);
+	return ret;
+}
+
+static int shifted_decompress(const struct z_erofs_decompress_req *rq,
+			      struct list_head *pagepool)
+{
+	const unsigned int nrpages_out =
+		PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
+	const unsigned int righthalf = PAGE_SIZE - rq->pageofs_out;
+	unsigned char *src, *dst;
+
+	if (nrpages_out > 2) {
+		DBG_BUGON(1);
+		return -EIO;
+	}
+
+	if (rq->out[0] == *rq->in) {
+		DBG_BUGON(nrpages_out != 1);
+		return 0;
+	}
+
+	src = kmap_atomic(*rq->in);
+	if (!rq->out[0]) {
+		dst = NULL;
+	} else {
+		dst = kmap_atomic(rq->out[0]);
+		memcpy(dst + rq->pageofs_out, src, righthalf);
+	}
+
+	if (rq->out[1] == *rq->in) {
+		memmove(src, src + righthalf, rq->pageofs_out);
+	} else if (nrpages_out == 2) {
+		if (dst)
+			kunmap_atomic(dst);
+		DBG_BUGON(!rq->out[1]);
+		dst = kmap_atomic(rq->out[1]);
+		memcpy(dst, src + righthalf, rq->pageofs_out);
+	}
+	if (dst)
+		kunmap_atomic(dst);
+	kunmap_atomic(src);
+	return 0;
+}
+
+int z_erofs_decompress(struct z_erofs_decompress_req *rq,
+		       struct list_head *pagepool)
+{
+	if (rq->alg == Z_EROFS_COMPRESSION_SHIFTED)
+		return shifted_decompress(rq, pagepool);
+	return decompress_generic(rq, pagepool);
+}
+
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v6 21/24] erofs: introduce LZ4 decompression inplace
  2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
                   ` (19 preceding siblings ...)
  2019-08-02 12:53 ` [PATCH v6 20/24] erofs: introduce generic decompression backend Gao Xiang
@ 2019-08-02 12:53 ` Gao Xiang
  2019-08-02 12:53 ` [PATCH v6 22/24] erofs: introduce the decompression frontend Gao Xiang
                   ` (3 subsequent siblings)
  24 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-02 12:53 UTC (permalink / raw)
  To: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds
  Cc: linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei, Gao Xiang

compressed data will be usually loaded into last pages of
the extent (the last page for 4k) for in-place decompression
(more specifically, in-place IO), as ilustration below,

         start of compressed logical extent
           |                          end of this logical extent
           |                           |
     ______v___________________________v________
... |  page 6  |  page 7  |  page 8  |  page 9  | ...
    |__________|__________|__________|__________|
           .                         ^ .        ^
           .                         |compressed|
           .                         |   data   |
           .                           .        .
           |<          dstsize        >|<margin>|
                                       oend     iend
           op                        ip

Therefore, it's possible to do decompression inplace (thus no
memcpy at all) if the margin is sufficient and safe enough [1],
and it can be implemented only for fixed-size output compression
compared with fixed-size input compression.

No memcpy for most of in-place IO (about 99% of enwik9) after
decompression inplace is implemented and sequential read will
be improved of course (see the following patches for test results).

[1] https://github.com/lz4/lz4/commit/b17f578a919b7e6b078cede2d52be29dd48c8e8c
    https://github.com/lz4/lz4/commit/5997e139f53169fa3a1c1b4418d2452a90b01602

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/decompressor.c | 36 ++++++++++++++++++++++++++++++++----
 fs/erofs/erofs_fs.h     |  2 +-
 2 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index 244afb29907d..1e9e1359e40c 100644
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -15,6 +15,9 @@
 #endif
 
 #define LZ4_MAX_DISTANCE_PAGES	(DIV_ROUND_UP(LZ4_DISTANCE_MAX, PAGE_SIZE) + 1)
+#ifndef LZ4_DECOMPRESS_INPLACE_MARGIN
+#define LZ4_DECOMPRESS_INPLACE_MARGIN(srcsize)  (((srcsize) >> 8) + 32)
+#endif
 
 struct z_erofs_decompressor {
 	/*
@@ -117,7 +120,7 @@ static int lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out)
 {
 	unsigned int inputmargin, inlen;
 	u8 *src;
-	bool copied;
+	bool copied, support_0padding;
 	int ret;
 
 	if (rq->inputsize > PAGE_SIZE)
@@ -125,13 +128,38 @@ static int lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out)
 
 	src = kmap_atomic(*rq->in);
 	inputmargin = 0;
+	support_0padding = false;
+
+	/* decompression inplace is only safe when 0padding is enabled */
+	if (EROFS_SB(rq->sb)->requirements & EROFS_REQUIREMENT_LZ4_0PADDING) {
+		support_0padding = true;
+
+		while (!src[inputmargin & ~PAGE_MASK])
+			if (!(++inputmargin & ~PAGE_MASK))
+				break;
+
+		if (inputmargin >= rq->inputsize) {
+			kunmap_atomic(src);
+			return -EIO;
+		}
+	}
 
 	copied = false;
 	inlen = rq->inputsize - inputmargin;
 	if (rq->inplace_io) {
-		src = generic_copy_inplace_data(rq, src, inputmargin);
-		inputmargin = 0;
-		copied = true;
+		const uint oend = (rq->pageofs_out +
+				   rq->outputsize) & ~PAGE_MASK;
+		const uint nr = PAGE_ALIGN(rq->pageofs_out +
+					   rq->outputsize) >> PAGE_SHIFT;
+
+		if (rq->partial_decoding || !support_0padding ||
+		    rq->out[nr - 1] != rq->in[0] ||
+		    rq->inputsize - oend <
+		      LZ4_DECOMPRESS_INPLACE_MARGIN(inlen)) {
+			src = generic_copy_inplace_data(rq, src, inputmargin);
+			inputmargin = 0;
+			copied = true;
+		}
 	}
 
 	ret = LZ4_decompress_safe_partial(src + inputmargin, out,
diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
index b307060dd220..25bda459f2e6 100644
--- a/fs/erofs/erofs_fs.h
+++ b/fs/erofs/erofs_fs.h
@@ -17,7 +17,7 @@
  * incompatible with this kernel version.
  */
 #define EROFS_REQUIREMENT_LZ4_0PADDING	0x00000001
-#define EROFS_ALL_REQUIREMENTS		0
+#define EROFS_ALL_REQUIREMENTS		EROFS_REQUIREMENT_LZ4_0PADDING
 
 struct erofs_super_block {
 /*  0 */__le32 magic;           /* in the little endian */
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v6 22/24] erofs: introduce the decompression frontend
  2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
                   ` (20 preceding siblings ...)
  2019-08-02 12:53 ` [PATCH v6 21/24] erofs: introduce LZ4 decompression inplace Gao Xiang
@ 2019-08-02 12:53 ` Gao Xiang
  2019-08-02 12:53 ` [PATCH v6 23/24] erofs: introduce cached decompression Gao Xiang
                   ` (2 subsequent siblings)
  24 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-02 12:53 UTC (permalink / raw)
  To: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds
  Cc: linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei, Gao Xiang

This patch introduces the basic inplace fixed-sized
output decompression implementation for erofs
filesystem.

In constant to fixed-sized input compression, it has
fixed-sized capacity for each compressed cluster to
contain compressed data with the following advantages:
 1) improved storage density;
 2) decompression inplace support;
 3) all data in a compressed physical cluster can be
    decompressed and utilized.

The key point of inplace refers to one of all erofs
decompression strategies: Instead of allocating extra
compressed pages and data management structures, it
reuses the allocated file cache pages as much as
possible to store its compressed data (called inplace
I/O) and the corresponding pagevec in a time-sharing
approach, which is particularly useful for low memory
scenario.

In addition, decompression inplace technology is based
on inplace I/O, which eliminates page allocation and
all extra compressed data memcpy.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/Kconfig    |    1 +
 fs/erofs/Makefile   |    2 +-
 fs/erofs/internal.h |   14 +-
 fs/erofs/super.c    |   11 +
 fs/erofs/zdata.c    | 1254 +++++++++++++++++++++++++++++++++++++++++++
 fs/erofs/zdata.h    |  192 +++++++
 fs/erofs/zmap.c     |    4 +-
 7 files changed, 1474 insertions(+), 4 deletions(-)
 create mode 100644 fs/erofs/zdata.c
 create mode 100644 fs/erofs/zdata.h

diff --git a/fs/erofs/Kconfig b/fs/erofs/Kconfig
index 5f8787c0cf89..16316d1adca3 100644
--- a/fs/erofs/Kconfig
+++ b/fs/erofs/Kconfig
@@ -76,6 +76,7 @@ config EROFS_FS_ZIP
 	bool "EROFS Data Compression Support"
 	depends on EROFS_FS
 	select LZ4_DECOMPRESS
+	default y
 	help
 	  Enable fixed-sized output compression for EROFS.
 
diff --git a/fs/erofs/Makefile b/fs/erofs/Makefile
index 5594abca6f95..46f2aa4ba46c 100644
--- a/fs/erofs/Makefile
+++ b/fs/erofs/Makefile
@@ -7,5 +7,5 @@ ccflags-y += -DEROFS_VERSION=\"$(EROFS_VERSION)\"
 obj-$(CONFIG_EROFS_FS) += erofs.o
 erofs-objs := super.o inode.o data.o namei.o dir.o utils.o
 erofs-$(CONFIG_EROFS_FS_XATTR) += xattr.o
-erofs-$(CONFIG_EROFS_FS_ZIP) += decompressor.o zmap.o
+erofs-$(CONFIG_EROFS_FS_ZIP) += decompressor.o zmap.o zdata.o
 
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 1a322304560f..a492744435d4 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -69,6 +69,9 @@ struct erofs_sb_info {
 	/* the dedicated workstation for compression */
 	struct radix_tree_root workstn_tree;
 
+	/* threshold for decompression synchronously */
+	unsigned int max_sync_decompress_pages;
+
 	unsigned int shrinker_run_no;
 #endif	/* CONFIG_EROFS_FS_ZIP */
 	u32 blocks;
@@ -328,6 +331,9 @@ static inline bool is_inode_flat_inline(struct inode *inode)
 extern const struct super_operations erofs_sops;
 
 extern const struct address_space_operations erofs_raw_access_aops;
+#ifdef CONFIG_EROFS_FS_ZIP
+extern const struct address_space_operations z_erofs_vle_normalaccess_aops;
+#endif
 
 /*
  * Logical to physical block mapping, used by erofs_map_blocks()
@@ -488,7 +494,7 @@ int erofs_namei(struct inode *dir, struct qstr *name,
 /* dir.c */
 extern const struct file_operations erofs_dir_fops;
 
-/* utils.c */
+/* utils.c / zdata.c */
 struct page *erofs_allocpage(struct list_head *pool, gfp_t gfp, bool nofail);
 
 #if (EROFS_PCPUBUF_NR_PAGES > 0)
@@ -512,16 +518,20 @@ struct erofs_workgroup *erofs_find_workgroup(struct super_block *sb,
 					     pgoff_t index, bool *tag);
 int erofs_register_workgroup(struct super_block *sb,
 			     struct erofs_workgroup *grp, bool tag);
-static inline void erofs_workgroup_free_rcu(struct erofs_workgroup *grp) {}
+void erofs_workgroup_free_rcu(struct erofs_workgroup *grp);
 void erofs_shrinker_register(struct super_block *sb);
 void erofs_shrinker_unregister(struct super_block *sb);
 int __init erofs_init_shrinker(void);
 void erofs_exit_shrinker(void);
+int __init z_erofs_init_zip_subsystem(void);
+void z_erofs_exit_zip_subsystem(void);
 #else
 static inline void erofs_shrinker_register(struct super_block *sb) {}
 static inline void erofs_shrinker_unregister(struct super_block *sb) {}
 static inline int erofs_init_shrinker(void) { return 0; }
 static inline void erofs_exit_shrinker(void) {}
+static inline int z_erofs_init_zip_subsystem(void) { return 0; }
+static inline void z_erofs_exit_zip_subsystem(void) {}
 #endif	/* !CONFIG_EROFS_FS_ZIP */
 
 #endif	/* __EROFS_INTERNAL_H */
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index ea8d065068fa..bdac8abf3aa7 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -200,6 +200,9 @@ static unsigned int erofs_get_fault_rate(struct erofs_sb_info *sbi)
 /* set up default EROFS parameters */
 static void default_options(struct erofs_sb_info *sbi)
 {
+#ifdef CONFIG_EROFS_FS_ZIP
+	sbi->max_sync_decompress_pages = 3;
+#endif
 #ifdef CONFIG_EROFS_FS_XATTR
 	set_opt(sbi, XATTR_USER);
 #endif
@@ -420,6 +423,11 @@ static int __init erofs_module_init(void)
 	err = erofs_init_shrinker();
 	if (err)
 		goto shrinker_err;
+
+	err = z_erofs_init_zip_subsystem();
+	if (err)
+		goto zip_err;
+
 	err = register_filesystem(&erofs_fs_type);
 	if (err)
 		goto fs_err;
@@ -428,6 +436,8 @@ static int __init erofs_module_init(void)
 	return 0;
 
 fs_err:
+	z_erofs_exit_zip_subsystem();
+zip_err:
 	erofs_exit_shrinker();
 shrinker_err:
 	erofs_exit_inode_cache();
@@ -438,6 +448,7 @@ static int __init erofs_module_init(void)
 static void __exit erofs_module_exit(void)
 {
 	unregister_filesystem(&erofs_fs_type);
+	z_erofs_exit_zip_subsystem();
 	erofs_exit_shrinker();
 	erofs_exit_inode_cache();
 	infoln("successfully finalize erofs");
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
new file mode 100644
index 000000000000..ffa64b1d8908
--- /dev/null
+++ b/fs/erofs/zdata.c
@@ -0,0 +1,1254 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/fs/erofs/zdata.c
+ *
+ * Copyright (C) 2018 HUAWEI, Inc.
+ *             http://www.huawei.com/
+ * Created by Gao Xiang <gaoxiang25@huawei.com>
+ */
+#include "zdata.h"
+#include "compress.h"
+#include <linux/prefetch.h>
+
+#include <trace/events/erofs.h>
+
+/*
+ * a compressed_pages[] placeholder in order to avoid
+ * being filled with file pages for in-place decompression.
+ */
+#define PAGE_UNALLOCATED     ((void *)0x5F0E4B1D)
+
+/* how to allocate cached pages for a pcluster */
+enum z_erofs_cache_alloctype {
+	DONTALLOC,	/* don't allocate any cached pages */
+	DELAYEDALLOC,	/* delayed allocation (at the time of submitting io) */
+};
+
+/*
+ * tagged pointer with 1-bit tag for all compressed pages
+ * tag 0 - the page is just found with an extra page reference
+ */
+typedef tagptr1_t compressed_page_t;
+
+#define tag_compressed_page_justfound(page) \
+	tagptr_fold(compressed_page_t, page, 1)
+
+static struct workqueue_struct *z_erofs_workqueue __read_mostly;
+static struct kmem_cache *pcluster_cachep __read_mostly;
+
+void z_erofs_exit_zip_subsystem(void)
+{
+	destroy_workqueue(z_erofs_workqueue);
+	kmem_cache_destroy(pcluster_cachep);
+}
+
+static inline int init_unzip_workqueue(void)
+{
+	const unsigned int onlinecpus = num_possible_cpus();
+	const unsigned int flags = WQ_UNBOUND | WQ_HIGHPRI | WQ_CPU_INTENSIVE;
+
+	/*
+	 * no need to spawn too many threads, limiting threads could minimum
+	 * scheduling overhead, perhaps per-CPU threads should be better?
+	 */
+	z_erofs_workqueue = alloc_workqueue("erofs_unzipd", flags,
+					    onlinecpus + onlinecpus / 4);
+	return z_erofs_workqueue ? 0 : -ENOMEM;
+}
+
+static void init_once(void *ptr)
+{
+	struct z_erofs_pcluster *pcl = ptr;
+	struct z_erofs_collection *cl = z_erofs_primarycollection(pcl);
+	unsigned int i;
+
+	mutex_init(&cl->lock);
+	cl->nr_pages = 0;
+	cl->vcnt = 0;
+	for (i = 0; i < Z_EROFS_CLUSTER_MAX_PAGES; ++i)
+		pcl->compressed_pages[i] = NULL;
+}
+
+static void init_always(struct z_erofs_pcluster *pcl)
+{
+	struct z_erofs_collection *cl = z_erofs_primarycollection(pcl);
+
+	atomic_set(&pcl->obj.refcount, 1);
+
+	DBG_BUGON(cl->nr_pages);
+	DBG_BUGON(cl->vcnt);
+}
+
+int __init z_erofs_init_zip_subsystem(void)
+{
+	pcluster_cachep = kmem_cache_create("erofs_compress",
+					    Z_EROFS_WORKGROUP_SIZE, 0,
+					    SLAB_RECLAIM_ACCOUNT, init_once);
+	if (pcluster_cachep) {
+		if (!init_unzip_workqueue())
+			return 0;
+
+		kmem_cache_destroy(pcluster_cachep);
+	}
+	return -ENOMEM;
+}
+
+enum z_erofs_collectmode {
+	COLLECT_SECONDARY,
+	COLLECT_PRIMARY,
+	/*
+	 * The current collection was the tail of an exist chain, in addition
+	 * that the previous processed chained collections are all decided to
+	 * be hooked up to it.
+	 * A new chain will be created for the remaining collections which are
+	 * not processed yet, therefore different from COLLECT_PRIMARY_FOLLOWED,
+	 * the next collection cannot reuse the whole page safely in
+	 * the following scenario:
+	 *  ________________________________________________________________
+	 * |      tail (partial) page     |       head (partial) page       |
+	 * |   (belongs to the next cl)   |   (belongs to the current cl)   |
+	 * |_______PRIMARY_FOLLOWED_______|________PRIMARY_HOOKED___________|
+	 */
+	COLLECT_PRIMARY_HOOKED,
+	COLLECT_PRIMARY_FOLLOWED_NOINPLACE,
+	/*
+	 * The current collection has been linked with the owned chain, and
+	 * could also be linked with the remaining collections, which means
+	 * if the processing page is the tail page of the collection, thus
+	 * the current collection can safely use the whole page (since
+	 * the previous collection is under control) for in-place I/O, as
+	 * illustrated below:
+	 *  ________________________________________________________________
+	 * |  tail (partial) page |          head (partial) page           |
+	 * |  (of the current cl) |      (of the previous collection)      |
+	 * |  PRIMARY_FOLLOWED or |                                        |
+	 * |_____PRIMARY_HOOKED___|____________PRIMARY_FOLLOWED____________|
+	 *
+	 * [  (*) the above page can be used as inplace I/O.               ]
+	 */
+	COLLECT_PRIMARY_FOLLOWED,
+};
+
+struct z_erofs_collector {
+	struct z_erofs_pagevec_ctor vector;
+
+	struct z_erofs_pcluster *pcl;
+	struct z_erofs_collection *cl;
+	struct page **compressedpages;
+	z_erofs_next_pcluster_t owned_head;
+
+	enum z_erofs_collectmode mode;
+};
+
+struct z_erofs_decompress_frontend {
+	struct inode *const inode;
+
+	struct z_erofs_collector clt;
+	struct erofs_map_blocks map;
+
+	/* used for applying cache strategy on the fly */
+	bool backmost;
+	erofs_off_t headoffset;
+};
+
+#define COLLECTOR_INIT() { \
+	.owned_head = Z_EROFS_PCLUSTER_TAIL, \
+	.mode = COLLECT_PRIMARY_FOLLOWED }
+
+#define DECOMPRESS_FRONTEND_INIT(__i) { \
+	.inode = __i, .clt = COLLECTOR_INIT(), \
+	.backmost = true, }
+
+static struct page *z_pagemap_global[Z_EROFS_VMAP_GLOBAL_PAGES];
+static DEFINE_MUTEX(z_pagemap_global_lock);
+
+static void preload_compressed_pages(struct z_erofs_collector *clt,
+				     struct address_space *mc,
+				     enum z_erofs_cache_alloctype type,
+				     struct list_head *pagepool)
+{
+	/* nowhere to load compressed pages from */
+}
+
+/* page_type must be Z_EROFS_PAGE_TYPE_EXCLUSIVE */
+static inline bool try_inplace_io(struct z_erofs_collector *clt,
+				  struct page *page)
+{
+	struct z_erofs_pcluster *const pcl = clt->pcl;
+	const unsigned int clusterpages = BIT(pcl->clusterbits);
+
+	while (clt->compressedpages < pcl->compressed_pages + clusterpages) {
+		if (!cmpxchg(clt->compressedpages++, NULL, page))
+			return true;
+	}
+	return false;
+}
+
+/* callers must be with collection lock held */
+static int z_erofs_attach_page(struct z_erofs_collector *clt,
+			       struct page *page,
+			       enum z_erofs_page_type type)
+{
+	int ret;
+	bool occupied;
+
+	/* give priority for inplaceio */
+	if (clt->mode >= COLLECT_PRIMARY &&
+	    type == Z_EROFS_PAGE_TYPE_EXCLUSIVE &&
+	    try_inplace_io(clt, page))
+		return 0;
+
+	ret = z_erofs_pagevec_enqueue(&clt->vector,
+				      page, type, &occupied);
+	clt->cl->vcnt += (unsigned int)ret;
+
+	return ret ? 0 : -EAGAIN;
+}
+
+static enum z_erofs_collectmode
+try_to_claim_pcluster(struct z_erofs_pcluster *pcl,
+		      z_erofs_next_pcluster_t *owned_head)
+{
+	/* let's claim these following types of pclusters */
+retry:
+	if (pcl->next == Z_EROFS_PCLUSTER_NIL) {
+		/* type 1, nil pcluster */
+		if (cmpxchg(&pcl->next, Z_EROFS_PCLUSTER_NIL,
+			    *owned_head) != Z_EROFS_PCLUSTER_NIL)
+			goto retry;
+
+		*owned_head = &pcl->next;
+		/* lucky, I am the followee :) */
+		return COLLECT_PRIMARY_FOLLOWED;
+	} else if (pcl->next == Z_EROFS_PCLUSTER_TAIL) {
+		/*
+		 * type 2, link to the end of a existing open chain,
+		 * be careful that its submission itself is governed
+		 * by the original owned chain.
+		 */
+		if (cmpxchg(&pcl->next, Z_EROFS_PCLUSTER_TAIL,
+			    *owned_head) != Z_EROFS_PCLUSTER_TAIL)
+			goto retry;
+		*owned_head = Z_EROFS_PCLUSTER_TAIL;
+		return COLLECT_PRIMARY_HOOKED;
+	}
+	return COLLECT_PRIMARY;	/* :( better luck next time */
+}
+
+static struct z_erofs_collection *cllookup(struct z_erofs_collector *clt,
+					   struct inode *inode,
+					   struct erofs_map_blocks *map)
+{
+	struct erofs_workgroup *grp;
+	struct z_erofs_pcluster *pcl;
+	struct z_erofs_collection *cl;
+	unsigned int length;
+	bool tag;
+
+	grp = erofs_find_workgroup(inode->i_sb, map->m_pa >> PAGE_SHIFT, &tag);
+	if (!grp)
+		return NULL;
+
+	pcl = container_of(grp, struct z_erofs_pcluster, obj);
+
+	cl = z_erofs_primarycollection(pcl);
+	if (unlikely(cl->pageofs != (map->m_la & ~PAGE_MASK))) {
+		DBG_BUGON(1);
+		return ERR_PTR(-EIO);
+	}
+
+	length = READ_ONCE(pcl->length);
+	if (length & Z_EROFS_PCLUSTER_FULL_LENGTH) {
+		if ((map->m_llen << Z_EROFS_PCLUSTER_LENGTH_BIT) > length) {
+			DBG_BUGON(1);
+			return ERR_PTR(-EIO);
+		}
+	} else {
+		unsigned int llen = map->m_llen << Z_EROFS_PCLUSTER_LENGTH_BIT;
+
+		if (map->m_flags & EROFS_MAP_FULL_MAPPED)
+			llen |= Z_EROFS_PCLUSTER_FULL_LENGTH;
+
+		while (llen > length &&
+		       length != cmpxchg_relaxed(&pcl->length, length, llen)) {
+			cpu_relax();
+			length = READ_ONCE(pcl->length);
+		}
+	}
+	mutex_lock(&cl->lock);
+	clt->mode = try_to_claim_pcluster(pcl, &clt->owned_head);
+	clt->pcl = pcl;
+	clt->cl = cl;
+	return cl;
+}
+
+static struct z_erofs_collection *clregister(struct z_erofs_collector *clt,
+					     struct inode *inode,
+					     struct erofs_map_blocks *map)
+{
+	struct z_erofs_pcluster *pcl;
+	struct z_erofs_collection *cl;
+	int err;
+
+	/* no available workgroup, let's allocate one */
+	pcl = kmem_cache_alloc(pcluster_cachep, GFP_NOFS);
+	if (unlikely(!pcl))
+		return ERR_PTR(-ENOMEM);
+
+	init_always(pcl);
+	pcl->obj.index = map->m_pa >> PAGE_SHIFT;
+
+	pcl->length = (map->m_llen << Z_EROFS_PCLUSTER_LENGTH_BIT) |
+		(map->m_flags & EROFS_MAP_FULL_MAPPED ?
+			Z_EROFS_PCLUSTER_FULL_LENGTH : 0);
+
+	if (map->m_flags & EROFS_MAP_ZIPPED)
+		pcl->algorithmformat = Z_EROFS_COMPRESSION_LZ4;
+	else
+		pcl->algorithmformat = Z_EROFS_COMPRESSION_SHIFTED;
+
+	pcl->clusterbits = EROFS_V(inode)->z_physical_clusterbits[0];
+	pcl->clusterbits -= PAGE_SHIFT;
+
+	/* new pclusters should be claimed as type 1, primary and followed */
+	pcl->next = clt->owned_head;
+	clt->mode = COLLECT_PRIMARY_FOLLOWED;
+
+	cl = z_erofs_primarycollection(pcl);
+	cl->pageofs = map->m_la & ~PAGE_MASK;
+
+	/*
+	 * lock all primary followed works before visible to others
+	 * and mutex_trylock *never* fails for a new pcluster.
+	 */
+	mutex_trylock(&cl->lock);
+
+	err = erofs_register_workgroup(inode->i_sb, &pcl->obj, 0);
+	if (err) {
+		mutex_unlock(&cl->lock);
+		kmem_cache_free(pcluster_cachep, pcl);
+		return ERR_PTR(-EAGAIN);
+	}
+	clt->owned_head = &pcl->next;
+	clt->pcl = pcl;
+	clt->cl = cl;
+	return cl;
+}
+
+static int z_erofs_collector_begin(struct z_erofs_collector *clt,
+				   struct inode *inode,
+				   struct erofs_map_blocks *map)
+{
+	struct z_erofs_collection *cl;
+
+	DBG_BUGON(clt->cl);
+
+	/* must be Z_EROFS_PCLUSTER_TAIL or pointed to previous collection */
+	DBG_BUGON(clt->owned_head == Z_EROFS_PCLUSTER_NIL);
+	DBG_BUGON(clt->owned_head == Z_EROFS_PCLUSTER_TAIL_CLOSED);
+
+	if (!PAGE_ALIGNED(map->m_pa)) {
+		DBG_BUGON(1);
+		return -EINVAL;
+	}
+
+repeat:
+	cl = cllookup(clt, inode, map);
+	if (!cl) {
+		cl = clregister(clt, inode, map);
+
+		if (unlikely(cl == ERR_PTR(-EAGAIN)))
+			goto repeat;
+	}
+
+	if (IS_ERR(cl))
+		return PTR_ERR(cl);
+
+	z_erofs_pagevec_ctor_init(&clt->vector, Z_EROFS_NR_INLINE_PAGEVECS,
+				  cl->pagevec, cl->vcnt);
+
+	clt->compressedpages = clt->pcl->compressed_pages;
+	if (clt->mode <= COLLECT_PRIMARY) /* cannot do in-place I/O */
+		clt->compressedpages += Z_EROFS_CLUSTER_MAX_PAGES;
+	return 0;
+}
+
+/*
+ * keep in mind that no referenced pclusters will be freed
+ * only after a RCU grace period.
+ */
+static void z_erofs_rcu_callback(struct rcu_head *head)
+{
+	struct z_erofs_collection *const cl =
+		container_of(head, struct z_erofs_collection, rcu);
+
+	kmem_cache_free(pcluster_cachep,
+			container_of(cl, struct z_erofs_pcluster,
+				     primary_collection));
+}
+
+void erofs_workgroup_free_rcu(struct erofs_workgroup *grp)
+{
+	struct z_erofs_pcluster *const pcl =
+		container_of(grp, struct z_erofs_pcluster, obj);
+	struct z_erofs_collection *const cl = z_erofs_primarycollection(pcl);
+
+	call_rcu(&cl->rcu, z_erofs_rcu_callback);
+}
+
+static void z_erofs_collection_put(struct z_erofs_collection *cl)
+{
+	struct z_erofs_pcluster *const pcl =
+		container_of(cl, struct z_erofs_pcluster, primary_collection);
+
+	erofs_workgroup_put(&pcl->obj);
+}
+
+static bool z_erofs_collector_end(struct z_erofs_collector *clt)
+{
+	struct z_erofs_collection *cl = clt->cl;
+
+	if (!cl)
+		return false;
+
+	z_erofs_pagevec_ctor_exit(&clt->vector, false);
+	mutex_unlock(&cl->lock);
+
+	/*
+	 * if all pending pages are added, don't hold its reference
+	 * any longer if the pcluster isn't hosted by ourselves.
+	 */
+	if (clt->mode < COLLECT_PRIMARY_FOLLOWED_NOINPLACE)
+		z_erofs_collection_put(cl);
+
+	clt->cl = NULL;
+	return true;
+}
+
+static inline struct page *__stagingpage_alloc(struct list_head *pagepool,
+					       gfp_t gfp)
+{
+	struct page *page = erofs_allocpage(pagepool, gfp, true);
+
+	page->mapping = Z_EROFS_MAPPING_STAGING;
+	return page;
+}
+
+static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
+				struct page *page,
+				struct list_head *pagepool)
+{
+	struct inode *const inode = fe->inode;
+	struct erofs_sb_info *const sbi __maybe_unused = EROFS_I_SB(inode);
+	struct erofs_map_blocks *const map = &fe->map;
+	struct z_erofs_collector *const clt = &fe->clt;
+	const loff_t offset = page_offset(page);
+	bool tight = (clt->mode >= COLLECT_PRIMARY_HOOKED);
+
+	enum z_erofs_cache_alloctype cache_strategy;
+	enum z_erofs_page_type page_type;
+	unsigned int cur, end, spiltted, index;
+	int err = 0;
+
+	/* register locked file pages as online pages in pack */
+	z_erofs_onlinepage_init(page);
+
+	spiltted = 0;
+	end = PAGE_SIZE;
+repeat:
+	cur = end - 1;
+
+	/* lucky, within the range of the current map_blocks */
+	if (offset + cur >= map->m_la &&
+	    offset + cur < map->m_la + map->m_llen) {
+		/* didn't get a valid collection previously (very rare) */
+		if (!clt->cl)
+			goto restart_now;
+		goto hitted;
+	}
+
+	/* go ahead the next map_blocks */
+	debugln("%s: [out-of-range] pos %llu", __func__, offset + cur);
+
+	if (z_erofs_collector_end(clt))
+		fe->backmost = false;
+
+	map->m_la = offset + cur;
+	map->m_llen = 0;
+	err = z_erofs_map_blocks_iter(inode, map, 0);
+	if (unlikely(err))
+		goto err_out;
+
+restart_now:
+	if (unlikely(!(map->m_flags & EROFS_MAP_MAPPED)))
+		goto hitted;
+
+	err = z_erofs_collector_begin(clt, inode, map);
+	if (unlikely(err))
+		goto err_out;
+
+	/* preload all compressed pages (maybe downgrade role if necessary) */
+	preload_compressed_pages(clt, MNGD_MAPPING(sbi), DONTALLOC, pagepool);
+
+	tight &= (clt->mode >= COLLECT_PRIMARY_HOOKED);
+hitted:
+	cur = end - min_t(unsigned int, offset + end - map->m_la, end);
+	if (unlikely(!(map->m_flags & EROFS_MAP_MAPPED))) {
+		zero_user_segment(page, cur, end);
+		goto next_part;
+	}
+
+	/* let's derive page type */
+	page_type = cur ? Z_EROFS_VLE_PAGE_TYPE_HEAD :
+		(!spiltted ? Z_EROFS_PAGE_TYPE_EXCLUSIVE :
+			(tight ? Z_EROFS_PAGE_TYPE_EXCLUSIVE :
+				Z_EROFS_VLE_PAGE_TYPE_TAIL_SHARED));
+
+	if (cur)
+		tight &= (clt->mode >= COLLECT_PRIMARY_FOLLOWED);
+
+retry:
+	err = z_erofs_attach_page(clt, page, page_type);
+	/* should allocate an additional staging page for pagevec */
+	if (err == -EAGAIN) {
+		struct page *const newpage =
+			__stagingpage_alloc(pagepool, GFP_NOFS);
+
+		err = z_erofs_attach_page(clt, newpage,
+					  Z_EROFS_PAGE_TYPE_EXCLUSIVE);
+		if (likely(!err))
+			goto retry;
+	}
+
+	if (unlikely(err))
+		goto err_out;
+
+	index = page->index - (map->m_la >> PAGE_SHIFT);
+
+	z_erofs_onlinepage_fixup(page, index, true);
+
+	/* bump up the number of spiltted parts of a page */
+	++spiltted;
+	/* also update nr_pages */
+	clt->cl->nr_pages = max_t(pgoff_t, clt->cl->nr_pages, index + 1);
+next_part:
+	/* can be used for verification */
+	map->m_llen = offset + cur - map->m_la;
+
+	end = cur;
+	if (end > 0)
+		goto repeat;
+
+out:
+	z_erofs_onlinepage_endio(page);
+
+	debugln("%s, finish page: %pK spiltted: %u map->m_llen %llu",
+		__func__, page, spiltted, map->m_llen);
+	return err;
+
+	/* if some error occurred while processing this page */
+err_out:
+	SetPageError(page);
+	goto out;
+}
+
+static void z_erofs_vle_unzip_kickoff(void *ptr, int bios)
+{
+	tagptr1_t t = tagptr_init(tagptr1_t, ptr);
+	struct z_erofs_unzip_io *io = tagptr_unfold_ptr(t);
+	bool background = tagptr_unfold_tags(t);
+
+	if (!background) {
+		unsigned long flags;
+
+		spin_lock_irqsave(&io->u.wait.lock, flags);
+		if (!atomic_add_return(bios, &io->pending_bios))
+			wake_up_locked(&io->u.wait);
+		spin_unlock_irqrestore(&io->u.wait.lock, flags);
+		return;
+	}
+
+	if (!atomic_add_return(bios, &io->pending_bios))
+		queue_work(z_erofs_workqueue, &io->u.work);
+}
+
+static inline void z_erofs_vle_read_endio(struct bio *bio)
+{
+	struct erofs_sb_info *sbi = NULL;
+	blk_status_t err = bio->bi_status;
+	struct bio_vec *bvec;
+	struct bvec_iter_all iter_all;
+
+	bio_for_each_segment_all(bvec, bio, iter_all) {
+		struct page *page = bvec->bv_page;
+		bool cachemngd = false;
+
+		DBG_BUGON(PageUptodate(page));
+		DBG_BUGON(!page->mapping);
+
+		if (unlikely(!sbi && !z_erofs_page_is_staging(page))) {
+			sbi = EROFS_SB(page->mapping->host->i_sb);
+
+			if (time_to_inject(sbi, FAULT_READ_IO)) {
+				erofs_show_injection_info(FAULT_READ_IO);
+				err = BLK_STS_IOERR;
+			}
+		}
+
+		/* sbi should already be gotten if the page is managed */
+		if (sbi)
+			cachemngd = erofs_page_is_managed(sbi, page);
+
+		if (unlikely(err))
+			SetPageError(page);
+		else if (cachemngd)
+			SetPageUptodate(page);
+
+		if (cachemngd)
+			unlock_page(page);
+	}
+
+	z_erofs_vle_unzip_kickoff(bio->bi_private, -1);
+	bio_put(bio);
+}
+
+static int z_erofs_decompress_pcluster(struct super_block *sb,
+				       struct z_erofs_pcluster *pcl,
+				       struct list_head *pagepool)
+{
+	struct erofs_sb_info *const sbi = EROFS_SB(sb);
+	const unsigned int clusterpages = BIT(pcl->clusterbits);
+	struct z_erofs_pagevec_ctor ctor;
+	unsigned int i, outputsize, llen, nr_pages;
+	struct page *pages_onstack[Z_EROFS_VMAP_ONSTACK_PAGES];
+	struct page **pages, **compressed_pages, *page;
+
+	enum z_erofs_page_type page_type;
+	bool overlapped, partial;
+	struct z_erofs_collection *cl;
+	int err;
+
+	might_sleep();
+	cl = z_erofs_primarycollection(pcl);
+	DBG_BUGON(!READ_ONCE(cl->nr_pages));
+
+	mutex_lock(&cl->lock);
+	nr_pages = cl->nr_pages;
+
+	if (likely(nr_pages <= Z_EROFS_VMAP_ONSTACK_PAGES)) {
+		pages = pages_onstack;
+	} else if (nr_pages <= Z_EROFS_VMAP_GLOBAL_PAGES &&
+		   mutex_trylock(&z_pagemap_global_lock)) {
+		pages = z_pagemap_global;
+	} else {
+		gfp_t gfp_flags = GFP_KERNEL;
+
+		if (nr_pages > Z_EROFS_VMAP_GLOBAL_PAGES)
+			gfp_flags |= __GFP_NOFAIL;
+
+		pages = kvmalloc_array(nr_pages, sizeof(struct page *),
+				       gfp_flags);
+
+		/* fallback to global pagemap for the lowmem scenario */
+		if (unlikely(!pages)) {
+			mutex_lock(&z_pagemap_global_lock);
+			pages = z_pagemap_global;
+		}
+	}
+
+	for (i = 0; i < nr_pages; ++i)
+		pages[i] = NULL;
+
+	z_erofs_pagevec_ctor_init(&ctor, Z_EROFS_NR_INLINE_PAGEVECS,
+				  cl->pagevec, 0);
+
+	for (i = 0; i < cl->vcnt; ++i) {
+		unsigned int pagenr;
+
+		page = z_erofs_pagevec_dequeue(&ctor, &page_type);
+
+		/* all pages in pagevec ought to be valid */
+		DBG_BUGON(!page);
+		DBG_BUGON(!page->mapping);
+
+		if (z_erofs_put_stagingpage(pagepool, page))
+			continue;
+
+		if (page_type == Z_EROFS_VLE_PAGE_TYPE_HEAD)
+			pagenr = 0;
+		else
+			pagenr = z_erofs_onlinepage_index(page);
+
+		DBG_BUGON(pagenr >= nr_pages);
+		DBG_BUGON(pages[pagenr]);
+
+		pages[pagenr] = page;
+	}
+	z_erofs_pagevec_ctor_exit(&ctor, true);
+
+	overlapped = false;
+	compressed_pages = pcl->compressed_pages;
+
+	err = 0;
+	for (i = 0; i < clusterpages; ++i) {
+		unsigned int pagenr;
+
+		page = compressed_pages[i];
+
+		/* all compressed pages ought to be valid */
+		DBG_BUGON(!page);
+		DBG_BUGON(!page->mapping);
+
+		if (!z_erofs_page_is_staging(page)) {
+			if (erofs_page_is_managed(sbi, page)) {
+				if (unlikely(!PageUptodate(page)))
+					err = -EIO;
+				continue;
+			}
+
+			/*
+			 * only if non-head page can be selected
+			 * for inplace decompression
+			 */
+			pagenr = z_erofs_onlinepage_index(page);
+
+			DBG_BUGON(pagenr >= nr_pages);
+			DBG_BUGON(pages[pagenr]);
+			pages[pagenr] = page;
+
+			overlapped = true;
+		}
+
+		/* PG_error needs checking for inplaced and staging pages */
+		if (unlikely(PageError(page))) {
+			DBG_BUGON(PageUptodate(page));
+			err = -EIO;
+		}
+	}
+
+	if (unlikely(err))
+		goto out;
+
+	llen = pcl->length >> Z_EROFS_PCLUSTER_LENGTH_BIT;
+	if (nr_pages << PAGE_SHIFT >= cl->pageofs + llen) {
+		outputsize = llen;
+		partial = !(pcl->length & Z_EROFS_PCLUSTER_FULL_LENGTH);
+	} else {
+		outputsize = (nr_pages << PAGE_SHIFT) - cl->pageofs;
+		partial = true;
+	}
+
+	err = z_erofs_decompress(&(struct z_erofs_decompress_req) {
+					.sb = sb,
+					.in = compressed_pages,
+					.out = pages,
+					.pageofs_out = cl->pageofs,
+					.inputsize = PAGE_SIZE,
+					.outputsize = outputsize,
+					.alg = pcl->algorithmformat,
+					.inplace_io = overlapped,
+					.partial_decoding = partial
+				 }, pagepool);
+
+out:
+	/* must handle all compressed pages before endding pages */
+	for (i = 0; i < clusterpages; ++i) {
+		page = compressed_pages[i];
+
+		if (erofs_page_is_managed(sbi, page))
+			continue;
+
+		/* recycle all individual staging pages */
+		(void)z_erofs_put_stagingpage(pagepool, page);
+
+		WRITE_ONCE(compressed_pages[i], NULL);
+	}
+
+	for (i = 0; i < nr_pages; ++i) {
+		page = pages[i];
+		if (!page)
+			continue;
+
+		DBG_BUGON(!page->mapping);
+
+		/* recycle all individual staging pages */
+		if (z_erofs_put_stagingpage(pagepool, page))
+			continue;
+
+		if (unlikely(err < 0))
+			SetPageError(page);
+
+		z_erofs_onlinepage_endio(page);
+	}
+
+	if (pages == z_pagemap_global)
+		mutex_unlock(&z_pagemap_global_lock);
+	else if (unlikely(pages != pages_onstack))
+		kvfree(pages);
+
+	cl->nr_pages = 0;
+	cl->vcnt = 0;
+
+	/* all cl locks MUST be taken before the following line */
+	WRITE_ONCE(pcl->next, Z_EROFS_PCLUSTER_NIL);
+
+	/* all cl locks SHOULD be released right now */
+	mutex_unlock(&cl->lock);
+
+	z_erofs_collection_put(cl);
+	return err;
+}
+
+static void z_erofs_vle_unzip_all(struct super_block *sb,
+				  struct z_erofs_unzip_io *io,
+				  struct list_head *pagepool)
+{
+	z_erofs_next_pcluster_t owned = io->head;
+
+	while (owned != Z_EROFS_PCLUSTER_TAIL_CLOSED) {
+		struct z_erofs_pcluster *pcl;
+
+		/* no possible that 'owned' equals Z_EROFS_WORK_TPTR_TAIL */
+		DBG_BUGON(owned == Z_EROFS_PCLUSTER_TAIL);
+
+		/* no possible that 'owned' equals NULL */
+		DBG_BUGON(owned == Z_EROFS_PCLUSTER_NIL);
+
+		pcl = container_of(owned, struct z_erofs_pcluster, next);
+		owned = READ_ONCE(pcl->next);
+
+		z_erofs_decompress_pcluster(sb, pcl, pagepool);
+	}
+}
+
+static void z_erofs_vle_unzip_wq(struct work_struct *work)
+{
+	struct z_erofs_unzip_io_sb *iosb =
+		container_of(work, struct z_erofs_unzip_io_sb, io.u.work);
+	LIST_HEAD(pagepool);
+
+	DBG_BUGON(iosb->io.head == Z_EROFS_PCLUSTER_TAIL_CLOSED);
+	z_erofs_vle_unzip_all(iosb->sb, &iosb->io, &pagepool);
+
+	put_pages_list(&pagepool);
+	kvfree(iosb);
+}
+
+static struct page *pickup_page_for_submission(struct z_erofs_pcluster *pcl,
+					       unsigned int nr,
+					       struct list_head *pagepool,
+					       struct address_space *mc,
+					       gfp_t gfp)
+{
+	/* determined at compile time to avoid too many #ifdefs */
+	const bool nocache = __builtin_constant_p(mc) ? !mc : false;
+	const pgoff_t index = pcl->obj.index;
+	bool tocache = false;
+
+	struct address_space *mapping;
+	struct page *oldpage, *page;
+
+	compressed_page_t t;
+	int justfound;
+
+repeat:
+	page = READ_ONCE(pcl->compressed_pages[nr]);
+	oldpage = page;
+
+	if (!page)
+		goto out_allocpage;
+
+	/*
+	 * the cached page has not been allocated and
+	 * an placeholder is out there, prepare it now.
+	 */
+	if (!nocache && page == PAGE_UNALLOCATED) {
+		tocache = true;
+		goto out_allocpage;
+	}
+
+	/* process the target tagged pointer */
+	t = tagptr_init(compressed_page_t, page);
+	justfound = tagptr_unfold_tags(t);
+	page = tagptr_unfold_ptr(t);
+
+	mapping = READ_ONCE(page->mapping);
+
+	/*
+	 * if managed cache is disabled, it's no way to
+	 * get such a cached-like page.
+	 */
+	if (nocache) {
+		/* if managed cache is disabled, it is impossible `justfound' */
+		DBG_BUGON(justfound);
+
+		/* and it should be locked, not uptodate, and not truncated */
+		DBG_BUGON(!PageLocked(page));
+		DBG_BUGON(PageUptodate(page));
+		DBG_BUGON(!mapping);
+		goto out;
+	}
+
+	/*
+	 * unmanaged (file) pages are all locked solidly,
+	 * therefore it is impossible for `mapping' to be NULL.
+	 */
+	if (mapping && mapping != mc)
+		/* ought to be unmanaged pages */
+		goto out;
+
+	lock_page(page);
+
+	/* only true if page reclaim goes wrong, should never happen */
+	DBG_BUGON(justfound && PagePrivate(page));
+
+	/* the page is still in manage cache */
+	if (page->mapping == mc) {
+		WRITE_ONCE(pcl->compressed_pages[nr], page);
+
+		ClearPageError(page);
+		if (!PagePrivate(page)) {
+			/*
+			 * impossible to be !PagePrivate(page) for
+			 * the current restriction as well if
+			 * the page is already in compressed_pages[].
+			 */
+			DBG_BUGON(!justfound);
+
+			justfound = 0;
+			set_page_private(page, (unsigned long)pcl);
+			SetPagePrivate(page);
+		}
+
+		/* no need to submit io if it is already up-to-date */
+		if (PageUptodate(page)) {
+			unlock_page(page);
+			page = NULL;
+		}
+		goto out;
+	}
+
+	/*
+	 * the managed page has been truncated, it's unsafe to
+	 * reuse this one, let's allocate a new cache-managed page.
+	 */
+	DBG_BUGON(page->mapping);
+	DBG_BUGON(!justfound);
+
+	tocache = true;
+	unlock_page(page);
+	put_page(page);
+out_allocpage:
+	page = __stagingpage_alloc(pagepool, gfp);
+	if (oldpage != cmpxchg(&pcl->compressed_pages[nr], oldpage, page)) {
+		list_add(&page->lru, pagepool);
+		cpu_relax();
+		goto repeat;
+	}
+	if (nocache || !tocache)
+		goto out;
+	if (add_to_page_cache_lru(page, mc, index + nr, gfp)) {
+		page->mapping = Z_EROFS_MAPPING_STAGING;
+		goto out;
+	}
+
+	set_page_private(page, (unsigned long)pcl);
+	SetPagePrivate(page);
+out:	/* the only exit (for tracing and debugging) */
+	return page;
+}
+
+static struct z_erofs_unzip_io *jobqueue_init(struct super_block *sb,
+					      struct z_erofs_unzip_io *io,
+					      bool foreground)
+{
+	struct z_erofs_unzip_io_sb *iosb;
+
+	if (foreground) {
+		/* waitqueue available for foreground io */
+		DBG_BUGON(!io);
+
+		init_waitqueue_head(&io->u.wait);
+		atomic_set(&io->pending_bios, 0);
+		goto out;
+	}
+
+	iosb = kvzalloc(sizeof(*iosb), GFP_KERNEL | __GFP_NOFAIL);
+	DBG_BUGON(!iosb);
+
+	/* initialize fields in the allocated descriptor */
+	io = &iosb->io;
+	iosb->sb = sb;
+	INIT_WORK(&io->u.work, z_erofs_vle_unzip_wq);
+out:
+	io->head = Z_EROFS_PCLUSTER_TAIL_CLOSED;
+	return io;
+}
+
+/* define decompression jobqueue types */
+enum {
+	JQ_SUBMIT,
+	NR_JOBQUEUES,
+};
+
+static void *jobqueueset_init(struct super_block *sb,
+			      z_erofs_next_pcluster_t qtail[],
+			      struct z_erofs_unzip_io *q[],
+			      struct z_erofs_unzip_io *fgq,
+			      bool forcefg)
+{
+	q[JQ_SUBMIT] = jobqueue_init(sb, fgq + JQ_SUBMIT, forcefg);
+	qtail[JQ_SUBMIT] = &q[JQ_SUBMIT]->head;
+
+	return tagptr_cast_ptr(tagptr_fold(tagptr1_t, q[JQ_SUBMIT], !forcefg));
+}
+
+static void move_to_bypass_jobqueue(struct z_erofs_pcluster *pcl,
+				    z_erofs_next_pcluster_t qtail[],
+				    z_erofs_next_pcluster_t owned_head)
+{
+	/* impossible to bypass submission for managed cache disabled */
+	DBG_BUGON(1);
+}
+
+static bool postsubmit_is_all_bypassed(struct z_erofs_unzip_io *q[],
+				       unsigned int nr_bios,
+				       bool force_fg)
+{
+	/* bios should be >0 if managed cache is disabled */
+	DBG_BUGON(!nr_bios);
+	return false;
+}
+
+static bool z_erofs_vle_submit_all(struct super_block *sb,
+				   z_erofs_next_pcluster_t owned_head,
+				   struct list_head *pagepool,
+				   struct z_erofs_unzip_io *fgq,
+				   bool force_fg)
+{
+	struct erofs_sb_info *const sbi __maybe_unused = EROFS_SB(sb);
+	z_erofs_next_pcluster_t qtail[NR_JOBQUEUES];
+	struct z_erofs_unzip_io *q[NR_JOBQUEUES];
+	struct bio *bio;
+	void *bi_private;
+	/* since bio will be NULL, no need to initialize last_index */
+	pgoff_t uninitialized_var(last_index);
+	bool force_submit = false;
+	unsigned int nr_bios;
+
+	if (unlikely(owned_head == Z_EROFS_PCLUSTER_TAIL))
+		return false;
+
+	force_submit = false;
+	bio = NULL;
+	nr_bios = 0;
+	bi_private = jobqueueset_init(sb, qtail, q, fgq, force_fg);
+
+	/* by default, all need io submission */
+	q[JQ_SUBMIT]->head = owned_head;
+
+	do {
+		struct z_erofs_pcluster *pcl;
+		unsigned int clusterpages;
+		pgoff_t first_index;
+		struct page *page;
+		unsigned int i = 0, bypass = 0;
+		int err;
+
+		/* no possible 'owned_head' equals the following */
+		DBG_BUGON(owned_head == Z_EROFS_PCLUSTER_TAIL_CLOSED);
+		DBG_BUGON(owned_head == Z_EROFS_PCLUSTER_NIL);
+
+		pcl = container_of(owned_head, struct z_erofs_pcluster, next);
+
+		clusterpages = BIT(pcl->clusterbits);
+
+		/* close the main owned chain at first */
+		owned_head = cmpxchg(&pcl->next, Z_EROFS_PCLUSTER_TAIL,
+				     Z_EROFS_PCLUSTER_TAIL_CLOSED);
+
+		first_index = pcl->obj.index;
+		force_submit |= (first_index != last_index + 1);
+
+repeat:
+		page = pickup_page_for_submission(pcl, i, pagepool,
+						  MNGD_MAPPING(sbi),
+						  GFP_NOFS);
+		if (!page) {
+			force_submit = true;
+			++bypass;
+			goto skippage;
+		}
+
+		if (bio && force_submit) {
+submit_bio_retry:
+			__submit_bio(bio, REQ_OP_READ, 0);
+			bio = NULL;
+		}
+
+		if (!bio) {
+			bio = erofs_grab_bio(sb, first_index + i,
+					     BIO_MAX_PAGES, bi_private,
+					     z_erofs_vle_read_endio, true);
+			++nr_bios;
+		}
+
+		err = bio_add_page(bio, page, PAGE_SIZE, 0);
+		if (err < PAGE_SIZE)
+			goto submit_bio_retry;
+
+		force_submit = false;
+		last_index = first_index + i;
+skippage:
+		if (++i < clusterpages)
+			goto repeat;
+
+		if (bypass < clusterpages)
+			qtail[JQ_SUBMIT] = &pcl->next;
+		else
+			move_to_bypass_jobqueue(pcl, qtail, owned_head);
+	} while (owned_head != Z_EROFS_PCLUSTER_TAIL);
+
+	if (bio)
+		__submit_bio(bio, REQ_OP_READ, 0);
+
+	if (postsubmit_is_all_bypassed(q, nr_bios, force_fg))
+		return true;
+
+	z_erofs_vle_unzip_kickoff(bi_private, nr_bios);
+	return true;
+}
+
+static void z_erofs_submit_and_unzip(struct super_block *sb,
+				     struct z_erofs_collector *clt,
+				     struct list_head *pagepool,
+				     bool force_fg)
+{
+	struct z_erofs_unzip_io io[NR_JOBQUEUES];
+
+	if (!z_erofs_vle_submit_all(sb, clt->owned_head,
+				    pagepool, io, force_fg))
+		return;
+
+	if (!force_fg)
+		return;
+
+	/* wait until all bios are completed */
+	wait_event(io[JQ_SUBMIT].u.wait,
+		   !atomic_read(&io[JQ_SUBMIT].pending_bios));
+
+	/* let's synchronous decompression */
+	z_erofs_vle_unzip_all(sb, &io[JQ_SUBMIT], pagepool);
+}
+
+static int z_erofs_vle_normalaccess_readpage(struct file *file,
+					     struct page *page)
+{
+	struct inode *const inode = page->mapping->host;
+	struct z_erofs_decompress_frontend f = DECOMPRESS_FRONTEND_INIT(inode);
+	int err;
+	LIST_HEAD(pagepool);
+
+	trace_erofs_readpage(page, false);
+
+	f.headoffset = (erofs_off_t)page->index << PAGE_SHIFT;
+
+	err = z_erofs_do_read_page(&f, page, &pagepool);
+	(void)z_erofs_collector_end(&f.clt);
+
+	if (err) {
+		errln("%s, failed to read, err [%d]", __func__, err);
+		goto out;
+	}
+
+	z_erofs_submit_and_unzip(inode->i_sb, &f.clt, &pagepool, true);
+out:
+	if (f.map.mpage)
+		put_page(f.map.mpage);
+
+	/* clean up the remaining free pages */
+	put_pages_list(&pagepool);
+	return 0;
+}
+
+static bool should_decompress_synchronously(struct erofs_sb_info *sbi,
+					    unsigned int nr)
+{
+	return nr <= sbi->max_sync_decompress_pages;
+}
+
+static int z_erofs_vle_normalaccess_readpages(struct file *filp,
+					      struct address_space *mapping,
+					      struct list_head *pages,
+					      unsigned int nr_pages)
+{
+	struct inode *const inode = mapping->host;
+	struct erofs_sb_info *const sbi = EROFS_I_SB(inode);
+
+	bool sync = should_decompress_synchronously(sbi, nr_pages);
+	struct z_erofs_decompress_frontend f = DECOMPRESS_FRONTEND_INIT(inode);
+	gfp_t gfp = mapping_gfp_constraint(mapping, GFP_KERNEL);
+	struct page *head = NULL;
+	LIST_HEAD(pagepool);
+
+	trace_erofs_readpages(mapping->host, lru_to_page(pages),
+			      nr_pages, false);
+
+	f.headoffset = (erofs_off_t)lru_to_page(pages)->index << PAGE_SHIFT;
+
+	for (; nr_pages; --nr_pages) {
+		struct page *page = lru_to_page(pages);
+
+		prefetchw(&page->flags);
+		list_del(&page->lru);
+
+		/*
+		 * A pure asynchronous readahead is indicated if
+		 * a PG_readahead marked page is hitted at first.
+		 * Let's also do asynchronous decompression for this case.
+		 */
+		sync &= !(PageReadahead(page) && !head);
+
+		if (add_to_page_cache_lru(page, mapping, page->index, gfp)) {
+			list_add(&page->lru, &pagepool);
+			continue;
+		}
+
+		set_page_private(page, (unsigned long)head);
+		head = page;
+	}
+
+	while (head) {
+		struct page *page = head;
+		int err;
+
+		/* traversal in reverse order */
+		head = (void *)page_private(page);
+
+		err = z_erofs_do_read_page(&f, page, &pagepool);
+		if (err) {
+			struct erofs_vnode *vi = EROFS_V(inode);
+
+			errln("%s, readahead error at page %lu of nid %llu",
+			      __func__, page->index, vi->nid);
+		}
+		put_page(page);
+	}
+
+	(void)z_erofs_collector_end(&f.clt);
+
+	z_erofs_submit_and_unzip(inode->i_sb, &f.clt, &pagepool, sync);
+
+	if (f.map.mpage)
+		put_page(f.map.mpage);
+
+	/* clean up the remaining free pages */
+	put_pages_list(&pagepool);
+	return 0;
+}
+
+const struct address_space_operations z_erofs_vle_normalaccess_aops = {
+	.readpage = z_erofs_vle_normalaccess_readpage,
+	.readpages = z_erofs_vle_normalaccess_readpages,
+};
+
diff --git a/fs/erofs/zdata.h b/fs/erofs/zdata.h
new file mode 100644
index 000000000000..3a82ae933015
--- /dev/null
+++ b/fs/erofs/zdata.h
@@ -0,0 +1,192 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * linux/fs/erofs/zdata.h
+ *
+ * Copyright (C) 2018 HUAWEI, Inc.
+ *             http://www.huawei.com/
+ * Created by Gao Xiang <gaoxiang25@huawei.com>
+ */
+#ifndef __EROFS_FS_ZDATA_H
+#define __EROFS_FS_ZDATA_H
+
+#include "internal.h"
+#include "zpvec.h"
+
+#define Z_EROFS_NR_INLINE_PAGEVECS      3
+
+/*
+ * Structure fields follow one of the following exclusion rules.
+ *
+ * I: Modifiable by initialization/destruction paths and read-only
+ *    for everyone else;
+ *
+ * L: Field should be protected by pageset lock;
+ *
+ * A: Field should be accessed / updated in atomic for parallelized code.
+ */
+struct z_erofs_collection {
+	struct mutex lock;
+
+	/* I: page offset of start position of decompression */
+	unsigned short pageofs;
+
+	/* L: maximum relative page index in pagevec[] */
+	unsigned short nr_pages;
+
+	/* L: total number of pages in pagevec[] */
+	unsigned int vcnt;
+
+	union {
+		/* L: inline a certain number of pagevecs for bootstrap */
+		erofs_vtptr_t pagevec[Z_EROFS_NR_INLINE_PAGEVECS];
+
+		/* I: can be used to free the pcluster by RCU. */
+		struct rcu_head rcu;
+	};
+};
+
+#define Z_EROFS_PCLUSTER_FULL_LENGTH    0x00000001
+#define Z_EROFS_PCLUSTER_LENGTH_BIT     1
+
+/*
+ * let's leave a type here in case of introducing
+ * another tagged pointer later.
+ */
+typedef void *z_erofs_next_pcluster_t;
+
+struct z_erofs_pcluster {
+	struct erofs_workgroup obj;
+	struct z_erofs_collection primary_collection;
+
+	/* A: point to next chained pcluster or TAILs */
+	z_erofs_next_pcluster_t next;
+
+	/* A: compressed pages (including multi-usage pages) */
+	struct page *compressed_pages[Z_EROFS_CLUSTER_MAX_PAGES];
+
+	/* A: lower limit of decompressed length and if full length or not */
+	unsigned int length;
+
+	/* I: compression algorithm format */
+	unsigned char algorithmformat;
+	/* I: bit shift of physical cluster size */
+	unsigned char clusterbits;
+};
+
+#define z_erofs_primarycollection(pcluster) (&(pcluster)->primary_collection)
+
+/* let's avoid the valid 32-bit kernel addresses */
+
+/* the chained workgroup has't submitted io (still open) */
+#define Z_EROFS_PCLUSTER_TAIL           ((void *)0x5F0ECAFE)
+/* the chained workgroup has already submitted io */
+#define Z_EROFS_PCLUSTER_TAIL_CLOSED    ((void *)0x5F0EDEAD)
+
+#define Z_EROFS_PCLUSTER_NIL            (NULL)
+
+#define Z_EROFS_WORKGROUP_SIZE  sizeof(struct z_erofs_pcluster)
+
+struct z_erofs_unzip_io {
+	atomic_t pending_bios;
+	z_erofs_next_pcluster_t head;
+
+	union {
+		wait_queue_head_t wait;
+		struct work_struct work;
+	} u;
+};
+
+struct z_erofs_unzip_io_sb {
+	struct z_erofs_unzip_io io;
+	struct super_block *sb;
+};
+
+#define MNGD_MAPPING(sbi)	(NULL)
+static inline bool erofs_page_is_managed(const struct erofs_sb_info *sbi,
+					 struct page *page) { return false; }
+
+#define Z_EROFS_ONLINEPAGE_COUNT_BITS   2
+#define Z_EROFS_ONLINEPAGE_COUNT_MASK   ((1 << Z_EROFS_ONLINEPAGE_COUNT_BITS) - 1)
+#define Z_EROFS_ONLINEPAGE_INDEX_SHIFT  (Z_EROFS_ONLINEPAGE_COUNT_BITS)
+
+/*
+ * waiters (aka. ongoing_packs): # to unlock the page
+ * sub-index: 0 - for partial page, >= 1 full page sub-index
+ */
+typedef atomic_t z_erofs_onlinepage_t;
+
+/* type punning */
+union z_erofs_onlinepage_converter {
+	z_erofs_onlinepage_t *o;
+	unsigned long *v;
+};
+
+static inline unsigned int z_erofs_onlinepage_index(struct page *page)
+{
+	union z_erofs_onlinepage_converter u;
+
+	DBG_BUGON(!PagePrivate(page));
+	u.v = &page_private(page);
+
+	return atomic_read(u.o) >> Z_EROFS_ONLINEPAGE_INDEX_SHIFT;
+}
+
+static inline void z_erofs_onlinepage_init(struct page *page)
+{
+	union {
+		z_erofs_onlinepage_t o;
+		unsigned long v;
+	/* keep from being unlocked in advance */
+	} u = { .o = ATOMIC_INIT(1) };
+
+	set_page_private(page, u.v);
+	smp_wmb();
+	SetPagePrivate(page);
+}
+
+static inline void z_erofs_onlinepage_fixup(struct page *page,
+	uintptr_t index, bool down)
+{
+	unsigned long *p, o, v, id;
+repeat:
+	p = &page_private(page);
+	o = READ_ONCE(*p);
+
+	id = o >> Z_EROFS_ONLINEPAGE_INDEX_SHIFT;
+	if (id) {
+		if (!index)
+			return;
+
+		DBG_BUGON(id != index);
+	}
+
+	v = (index << Z_EROFS_ONLINEPAGE_INDEX_SHIFT) |
+		((o & Z_EROFS_ONLINEPAGE_COUNT_MASK) + (unsigned int)down);
+	if (cmpxchg(p, o, v) != o)
+		goto repeat;
+}
+
+static inline void z_erofs_onlinepage_endio(struct page *page)
+{
+	union z_erofs_onlinepage_converter u;
+	unsigned int v;
+
+	DBG_BUGON(!PagePrivate(page));
+	u.v = &page_private(page);
+
+	v = atomic_dec_return(u.o);
+	if (!(v & Z_EROFS_ONLINEPAGE_COUNT_MASK)) {
+		ClearPagePrivate(page);
+		if (!PageError(page))
+			SetPageUptodate(page);
+		unlock_page(page);
+	}
+	debugln("%s, page %p value %x", __func__, page, atomic_read(u.o));
+}
+
+#define Z_EROFS_VMAP_ONSTACK_PAGES	\
+	min_t(unsigned int, THREAD_SIZE / 8 / sizeof(struct page *), 96U)
+#define Z_EROFS_VMAP_GLOBAL_PAGES	2048
+
+#endif
+
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index 8cd55c33f50b..d887ea6d4fd5 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -23,7 +23,9 @@ int z_erofs_fill_inode(struct inode *inode)
 		vi->z_physical_clusterbits[1] = vi->z_logical_clusterbits;
 		set_bit(EROFS_V_Z_INITED_BIT, &vi->flags);
 	}
-	return -ENOTSUPP;
+
+	inode->i_mapping->a_ops = &z_erofs_vle_normalaccess_aops;
+	return 0;
 }
 
 static int fill_inode_lazy(struct inode *inode)
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v6 23/24] erofs: introduce cached decompression
  2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
                   ` (21 preceding siblings ...)
  2019-08-02 12:53 ` [PATCH v6 22/24] erofs: introduce the decompression frontend Gao Xiang
@ 2019-08-02 12:53 ` Gao Xiang
  2019-08-02 12:53 ` [PATCH v6 24/24] erofs: add document Gao Xiang
  2019-09-01  5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang
  24 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-02 12:53 UTC (permalink / raw)
  To: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds
  Cc: linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei, Gao Xiang

This patch adds strategies which can be selected
by users in order to cache both incomplete ends of
compressed physical clusters as a complement of
in-place I/O in order to boost random read, but
it costs more memory than the in-place I/O only.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/internal.h |  16 +++++
 fs/erofs/super.c    | 126 ++++++++++++++++++++++++++++++++-
 fs/erofs/utils.c    |  40 ++++++++---
 fs/erofs/zdata.c    | 165 ++++++++++++++++++++++++++++++++++++++++++--
 fs/erofs/zdata.h    |   7 +-
 5 files changed, 336 insertions(+), 18 deletions(-)

diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index a492744435d4..f4b50b59cda3 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -73,6 +73,12 @@ struct erofs_sb_info {
 	unsigned int max_sync_decompress_pages;
 
 	unsigned int shrinker_run_no;
+
+	/* current strategy of how to use managed cache */
+	unsigned char cache_strategy;
+
+	/* pseudo inode to manage cached pages */
+	struct inode *managed_cache;
 #endif	/* CONFIG_EROFS_FS_ZIP */
 	u32 blocks;
 	u32 meta_blkaddr;
@@ -158,6 +164,12 @@ static inline void *erofs_kmalloc(struct erofs_sb_info *sbi,
 #define test_opt(sbi, option)	((sbi)->mount_opt & EROFS_MOUNT_##option)
 
 #ifdef CONFIG_EROFS_FS_ZIP
+enum {
+	EROFS_ZIP_CACHE_DISABLED,
+	EROFS_ZIP_CACHE_READAHEAD,
+	EROFS_ZIP_CACHE_READAROUND
+};
+
 #define EROFS_LOCKED_MAGIC     (INT_MIN | 0xE0F510CCL)
 
 /* basic unit of the workstation of a super_block */
@@ -525,6 +537,10 @@ int __init erofs_init_shrinker(void);
 void erofs_exit_shrinker(void);
 int __init z_erofs_init_zip_subsystem(void);
 void z_erofs_exit_zip_subsystem(void);
+int erofs_try_to_free_all_cached_pages(struct erofs_sb_info *sbi,
+				       struct erofs_workgroup *egrp);
+int erofs_try_to_free_cached_page(struct address_space *mapping,
+				  struct page *page);
 #else
 static inline void erofs_shrinker_register(struct super_block *sb) {}
 static inline void erofs_shrinker_unregister(struct super_block *sb) {}
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index bdac8abf3aa7..95187619b3e3 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -197,10 +197,45 @@ static unsigned int erofs_get_fault_rate(struct erofs_sb_info *sbi)
 }
 #endif
 
+#ifdef CONFIG_EROFS_FS_ZIP
+static int erofs_build_cache_strategy(struct erofs_sb_info *sbi,
+				      substring_t *args)
+{
+	const char *cs = match_strdup(args);
+	int err = 0;
+
+	if (!cs) {
+		errln("Not enough memory to store cache strategy");
+		return -ENOMEM;
+	}
+
+	if (!strcmp(cs, "disabled")) {
+		sbi->cache_strategy = EROFS_ZIP_CACHE_DISABLED;
+	} else if (!strcmp(cs, "readahead")) {
+		sbi->cache_strategy = EROFS_ZIP_CACHE_READAHEAD;
+	} else if (!strcmp(cs, "readaround")) {
+		sbi->cache_strategy = EROFS_ZIP_CACHE_READAROUND;
+	} else {
+		errln("Unrecognized cache strategy \"%s\"", cs);
+		err = -EINVAL;
+	}
+	kfree(cs);
+	return err;
+}
+#else
+static int erofs_build_cache_strategy(struct erofs_sb_info *sbi,
+				      substring_t *args)
+{
+	infoln("EROFS compression is disabled, so cache strategy is ignored");
+	return 0;
+}
+#endif
+
 /* set up default EROFS parameters */
 static void default_options(struct erofs_sb_info *sbi)
 {
 #ifdef CONFIG_EROFS_FS_ZIP
+	sbi->cache_strategy = EROFS_ZIP_CACHE_READAROUND;
 	sbi->max_sync_decompress_pages = 3;
 #endif
 #ifdef CONFIG_EROFS_FS_XATTR
@@ -217,6 +252,7 @@ enum {
 	Opt_acl,
 	Opt_noacl,
 	Opt_fault_injection,
+	Opt_cache_strategy,
 	Opt_err
 };
 
@@ -226,6 +262,7 @@ static match_table_t erofs_tokens = {
 	{Opt_acl, "acl"},
 	{Opt_noacl, "noacl"},
 	{Opt_fault_injection, "fault_injection=%u"},
+	{Opt_cache_strategy, "cache_strategy=%s"},
 	{Opt_err, NULL}
 };
 
@@ -283,6 +320,11 @@ static int parse_options(struct super_block *sb, char *options)
 			if (err)
 				return err;
 			break;
+		case Opt_cache_strategy:
+			err = erofs_build_cache_strategy(EROFS_SB(sb), args);
+			if (err)
+				return err;
+			break;
 		default:
 			errln("Unrecognized mount option \"%s\" or missing value", p);
 			return -EINVAL;
@@ -291,6 +333,65 @@ static int parse_options(struct super_block *sb, char *options)
 	return 0;
 }
 
+#ifdef CONFIG_EROFS_FS_ZIP
+static const struct address_space_operations managed_cache_aops;
+
+static int managed_cache_releasepage(struct page *page, gfp_t gfp_mask)
+{
+	int ret = 1;	/* 0 - busy */
+	struct address_space *const mapping = page->mapping;
+
+	DBG_BUGON(!PageLocked(page));
+	DBG_BUGON(mapping->a_ops != &managed_cache_aops);
+
+	if (PagePrivate(page))
+		ret = erofs_try_to_free_cached_page(mapping, page);
+
+	return ret;
+}
+
+static void managed_cache_invalidatepage(struct page *page,
+					 unsigned int offset,
+					 unsigned int length)
+{
+	const unsigned int stop = length + offset;
+
+	DBG_BUGON(!PageLocked(page));
+
+	/* Check for potential overflow in debug mode */
+	DBG_BUGON(stop > PAGE_SIZE || stop < length);
+
+	if (offset == 0 && stop == PAGE_SIZE)
+		while (!managed_cache_releasepage(page, GFP_NOFS))
+			cond_resched();
+}
+
+static const struct address_space_operations managed_cache_aops = {
+	.releasepage = managed_cache_releasepage,
+	.invalidatepage = managed_cache_invalidatepage,
+};
+
+static int erofs_init_managed_cache(struct super_block *sb)
+{
+	struct erofs_sb_info *const sbi = EROFS_SB(sb);
+	struct inode *const inode = new_inode(sb);
+
+	if (unlikely(!inode))
+		return -ENOMEM;
+
+	set_nlink(inode, 1);
+	inode->i_size = OFFSET_MAX;
+
+	inode->i_mapping->a_ops = &managed_cache_aops;
+	mapping_set_gfp_mask(inode->i_mapping,
+			     GFP_NOFS | __GFP_HIGHMEM | __GFP_MOVABLE);
+	sbi->managed_cache = inode;
+	return 0;
+}
+#else
+static int erofs_init_managed_cache(struct super_block *sb) { return 0; }
+#endif
+
 static int erofs_fill_super(struct super_block *sb, void *data, int silent)
 {
 	struct inode *inode;
@@ -325,7 +426,6 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
 #ifdef CONFIG_EROFS_FS_XATTR
 	sb->s_xattr = erofs_xattr_handlers;
 #endif
-
 	/* set erofs default mount options */
 	default_options(sbi);
 
@@ -362,6 +462,10 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
 		return -ENOMEM;
 
 	erofs_shrinker_register(sb);
+	/* sb->s_umount is already locked, SB_ACTIVE and SB_BORN are not set */
+	err = erofs_init_managed_cache(sb);
+	if (unlikely(err))
+		return err;
 
 	if (!silent)
 		infoln("mounted on %s with opts: %s.", sb->s_id, (char *)data);
@@ -397,7 +501,15 @@ static void erofs_kill_sb(struct super_block *sb)
 /* called when ->s_root is non-NULL */
 static void erofs_put_super(struct super_block *sb)
 {
+	struct erofs_sb_info *const sbi = EROFS_SB(sb);
+
+	DBG_BUGON(!sbi);
+
 	erofs_shrinker_unregister(sb);
+#ifdef CONFIG_EROFS_FS_ZIP
+	iput(sbi->managed_cache);
+	sbi->managed_cache = NULL;
+#endif
 }
 
 static struct file_system_type erofs_fs_type = {
@@ -495,6 +607,18 @@ static int erofs_show_options(struct seq_file *seq, struct dentry *root)
 	if (test_opt(sbi, FAULT_INJECTION))
 		seq_printf(seq, ",fault_injection=%u",
 			   erofs_get_fault_rate(sbi));
+#ifdef CONFIG_EROFS_FS_ZIP
+	if (sbi->cache_strategy == EROFS_ZIP_CACHE_DISABLED) {
+		seq_puts(seq, ",cache_strategy=disabled");
+	} else if (sbi->cache_strategy == EROFS_ZIP_CACHE_READAHEAD) {
+		seq_puts(seq, ",cache_strategy=readahead");
+	} else if (sbi->cache_strategy == EROFS_ZIP_CACHE_READAROUND) {
+		seq_puts(seq, ",cache_strategy=readaround");
+	} else {
+		seq_puts(seq, ",cache_strategy=(unknown)");
+		DBG_BUGON(1);
+	}
+#endif
 	return 0;
 }
 
diff --git a/fs/erofs/utils.c b/fs/erofs/utils.c
index ae6362abed67..c48e417d3926 100644
--- a/fs/erofs/utils.c
+++ b/fs/erofs/utils.c
@@ -144,24 +144,48 @@ int erofs_workgroup_put(struct erofs_workgroup *grp)
 	return count;
 }
 
-/* for nocache case, no customized reclaim path at all */
+static void erofs_workgroup_unfreeze_final(struct erofs_workgroup *grp)
+{
+	erofs_workgroup_unfreeze(grp, 0);
+	__erofs_workgroup_free(grp);
+}
+
 static bool erofs_try_to_release_workgroup(struct erofs_sb_info *sbi,
 					   struct erofs_workgroup *grp,
 					   bool cleanup)
 {
-	int cnt = atomic_read(&grp->refcount);
-
-	DBG_BUGON(cnt <= 0);
-	DBG_BUGON(cleanup && cnt != 1);
+	/*
+	 * If managed cache is on, refcount of workgroups
+	 * themselves could be < 0 (freezed). In other words,
+	 * there is no guarantee that all refcounts > 0.
+	 */
+	if (!erofs_workgroup_try_to_freeze(grp, 1))
+		return false;
 
-	if (cnt > 1)
+	/*
+	 * Note that all cached pages should be unattached
+	 * before deleted from the radix tree. Otherwise some
+	 * cached pages could be still attached to the orphan
+	 * old workgroup when the new one is available in the tree.
+	 */
+	if (erofs_try_to_free_all_cached_pages(sbi, grp)) {
+		erofs_workgroup_unfreeze(grp, 1);
 		return false;
+	}
 
+	/*
+	 * It's impossible to fail after the workgroup is freezed,
+	 * however in order to avoid some race conditions, add a
+	 * DBG_BUGON to observe this in advance.
+	 */
 	DBG_BUGON(xa_untag_pointer(radix_tree_delete(&sbi->workstn_tree,
 						     grp->index)) != grp);
 
-	/* (rarely) could be grabbed again when freeing */
-	erofs_workgroup_put(grp);
+	/*
+	 * If managed cache is on, last refcount should indicate
+	 * the related workstation.
+	 */
+	erofs_workgroup_unfreeze_final(grp);
 	return true;
 }
 
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index ffa64b1d8908..24be7d98bce3 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -167,7 +167,110 @@ static void preload_compressed_pages(struct z_erofs_collector *clt,
 				     enum z_erofs_cache_alloctype type,
 				     struct list_head *pagepool)
 {
-	/* nowhere to load compressed pages from */
+	const struct z_erofs_pcluster *pcl = clt->pcl;
+	const unsigned int clusterpages = BIT(pcl->clusterbits);
+	struct page **pages = clt->compressedpages;
+	pgoff_t index = pcl->obj.index + (pages - pcl->compressed_pages);
+	bool standalone = true;
+
+	if (clt->mode < COLLECT_PRIMARY_FOLLOWED)
+		return;
+
+	for (; pages < pcl->compressed_pages + clusterpages; ++pages) {
+		struct page *page;
+		compressed_page_t t;
+
+		/* the compressed page was loaded before */
+		if (READ_ONCE(*pages))
+			continue;
+
+		page = find_get_page(mc, index);
+
+		if (page) {
+			t = tag_compressed_page_justfound(page);
+		} else if (type == DELAYEDALLOC) {
+			t = tagptr_init(compressed_page_t, PAGE_UNALLOCATED);
+		} else {	/* DONTALLOC */
+			if (standalone)
+				clt->compressedpages = pages;
+			standalone = false;
+			continue;
+		}
+
+		if (!cmpxchg_relaxed(pages, NULL, tagptr_cast_ptr(t)))
+			continue;
+
+		if (page)
+			put_page(page);
+	}
+
+	if (standalone)		/* downgrade to PRIMARY_FOLLOWED_NOINPLACE */
+		clt->mode = COLLECT_PRIMARY_FOLLOWED_NOINPLACE;
+}
+
+/* called by erofs_shrinker to get rid of all compressed_pages */
+int erofs_try_to_free_all_cached_pages(struct erofs_sb_info *sbi,
+				       struct erofs_workgroup *grp)
+{
+	struct z_erofs_pcluster *const pcl =
+		container_of(grp, struct z_erofs_pcluster, obj);
+	struct address_space *const mapping = MNGD_MAPPING(sbi);
+	const unsigned int clusterpages = BIT(pcl->clusterbits);
+	int i;
+
+	/*
+	 * refcount of workgroup is now freezed as 1,
+	 * therefore no need to worry about available decompression users.
+	 */
+	for (i = 0; i < clusterpages; ++i) {
+		struct page *page = pcl->compressed_pages[i];
+
+		if (!page)
+			continue;
+
+		/* block other users from reclaiming or migrating the page */
+		if (!trylock_page(page))
+			return -EBUSY;
+
+		if (unlikely(page->mapping != mapping))
+			continue;
+
+		/* barrier is implied in the following 'unlock_page' */
+		WRITE_ONCE(pcl->compressed_pages[i], NULL);
+		set_page_private(page, 0);
+		ClearPagePrivate(page);
+
+		unlock_page(page);
+		put_page(page);
+	}
+	return 0;
+}
+
+int erofs_try_to_free_cached_page(struct address_space *mapping,
+				  struct page *page)
+{
+	struct z_erofs_pcluster *const pcl = (void *)page_private(page);
+	const unsigned int clusterpages = BIT(pcl->clusterbits);
+	int ret = 0;	/* 0 - busy */
+
+	if (erofs_workgroup_try_to_freeze(&pcl->obj, 1)) {
+		unsigned int i;
+
+		for (i = 0; i < clusterpages; ++i) {
+			if (pcl->compressed_pages[i] == page) {
+				WRITE_ONCE(pcl->compressed_pages[i], NULL);
+				ret = 1;
+				break;
+			}
+		}
+		erofs_workgroup_unfreeze(&pcl->obj, 1);
+
+		if (ret) {
+			ClearPagePrivate(page);
+			put_page(page);
+		}
+	}
+	return ret;
 }
 
 /* page_type must be Z_EROFS_PAGE_TYPE_EXCLUSIVE */
@@ -434,6 +537,20 @@ static inline struct page *__stagingpage_alloc(struct list_head *pagepool,
 	return page;
 }
 
+static bool should_alloc_managed_pages(struct z_erofs_decompress_frontend *fe,
+				       unsigned int cachestrategy,
+				       erofs_off_t la)
+{
+	if (cachestrategy <= EROFS_ZIP_CACHE_DISABLED)
+		return false;
+
+	if (fe->backmost)
+		return true;
+
+	return cachestrategy >= EROFS_ZIP_CACHE_READAROUND &&
+		la < fe->headoffset;
+}
+
 static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
 				struct page *page,
 				struct list_head *pagepool)
@@ -488,7 +605,13 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
 		goto err_out;
 
 	/* preload all compressed pages (maybe downgrade role if necessary) */
-	preload_compressed_pages(clt, MNGD_MAPPING(sbi), DONTALLOC, pagepool);
+	if (should_alloc_managed_pages(fe, sbi->cache_strategy, map->m_la))
+		cache_strategy = DELAYEDALLOC;
+	else
+		cache_strategy = DONTALLOC;
+
+	preload_compressed_pages(clt, MNGD_MAPPING(sbi),
+				 cache_strategy, pagepool);
 
 	tight &= (clt->mode >= COLLECT_PRIMARY_HOOKED);
 hitted:
@@ -987,6 +1110,7 @@ static struct z_erofs_unzip_io *jobqueue_init(struct super_block *sb,
 
 /* define decompression jobqueue types */
 enum {
+	JQ_BYPASS,
 	JQ_SUBMIT,
 	NR_JOBQUEUES,
 };
@@ -997,6 +1121,13 @@ static void *jobqueueset_init(struct super_block *sb,
 			      struct z_erofs_unzip_io *fgq,
 			      bool forcefg)
 {
+	/*
+	 * if managed cache is enabled, bypass jobqueue is needed,
+	 * no need to read from device for all pclusters in this queue.
+	 */
+	q[JQ_BYPASS] = jobqueue_init(sb, fgq + JQ_BYPASS, true);
+	qtail[JQ_BYPASS] = &q[JQ_BYPASS]->head;
+
 	q[JQ_SUBMIT] = jobqueue_init(sb, fgq + JQ_SUBMIT, forcefg);
 	qtail[JQ_SUBMIT] = &q[JQ_SUBMIT]->head;
 
@@ -1007,17 +1138,34 @@ static void move_to_bypass_jobqueue(struct z_erofs_pcluster *pcl,
 				    z_erofs_next_pcluster_t qtail[],
 				    z_erofs_next_pcluster_t owned_head)
 {
-	/* impossible to bypass submission for managed cache disabled */
-	DBG_BUGON(1);
+	z_erofs_next_pcluster_t *const submit_qtail = qtail[JQ_SUBMIT];
+	z_erofs_next_pcluster_t *const bypass_qtail = qtail[JQ_BYPASS];
+
+	DBG_BUGON(owned_head == Z_EROFS_PCLUSTER_TAIL_CLOSED);
+	if (owned_head == Z_EROFS_PCLUSTER_TAIL)
+		owned_head = Z_EROFS_PCLUSTER_TAIL_CLOSED;
+
+	WRITE_ONCE(pcl->next, Z_EROFS_PCLUSTER_TAIL_CLOSED);
+
+	WRITE_ONCE(*submit_qtail, owned_head);
+	WRITE_ONCE(*bypass_qtail, &pcl->next);
+
+	qtail[JQ_BYPASS] = &pcl->next;
 }
 
 static bool postsubmit_is_all_bypassed(struct z_erofs_unzip_io *q[],
 				       unsigned int nr_bios,
 				       bool force_fg)
 {
-	/* bios should be >0 if managed cache is disabled */
-	DBG_BUGON(!nr_bios);
-	return false;
+	/*
+	 * although background is preferred, no one is pending for submission.
+	 * don't issue workqueue for decompression but drop it directly instead.
+	 */
+	if (force_fg || nr_bios)
+		return false;
+
+	kvfree(container_of(q[JQ_SUBMIT], struct z_erofs_unzip_io_sb, io));
+	return true;
 }
 
 static bool z_erofs_vle_submit_all(struct super_block *sb,
@@ -1130,6 +1278,9 @@ static void z_erofs_submit_and_unzip(struct super_block *sb,
 				    pagepool, io, force_fg))
 		return;
 
+	/* decompress no I/O pclusters immediately */
+	z_erofs_vle_unzip_all(sb, &io[JQ_BYPASS], pagepool);
+
 	if (!force_fg)
 		return;
 
diff --git a/fs/erofs/zdata.h b/fs/erofs/zdata.h
index 3a82ae933015..506ca46727db 100644
--- a/fs/erofs/zdata.h
+++ b/fs/erofs/zdata.h
@@ -101,9 +101,12 @@ struct z_erofs_unzip_io_sb {
 	struct super_block *sb;
 };
 
-#define MNGD_MAPPING(sbi)	(NULL)
+#define MNGD_MAPPING(sbi)	((sbi)->managed_cache->i_mapping)
 static inline bool erofs_page_is_managed(const struct erofs_sb_info *sbi,
-					 struct page *page) { return false; }
+					 struct page *page)
+{
+	return page->mapping == MNGD_MAPPING(sbi);
+}
 
 #define Z_EROFS_ONLINEPAGE_COUNT_BITS   2
 #define Z_EROFS_ONLINEPAGE_COUNT_MASK   ((1 << Z_EROFS_ONLINEPAGE_COUNT_BITS) - 1)
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v6 24/24] erofs: add document
  2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
                   ` (22 preceding siblings ...)
  2019-08-02 12:53 ` [PATCH v6 23/24] erofs: introduce cached decompression Gao Xiang
@ 2019-08-02 12:53 ` Gao Xiang
  2019-09-01  5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang
  24 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-02 12:53 UTC (permalink / raw)
  To: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds
  Cc: linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei, Gao Xiang

This documents key features, usage, and
on-disk design of erofs.

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 Documentation/filesystems/erofs.txt | 225 ++++++++++++++++++++++++++++
 1 file changed, 225 insertions(+)
 create mode 100644 Documentation/filesystems/erofs.txt

diff --git a/Documentation/filesystems/erofs.txt b/Documentation/filesystems/erofs.txt
new file mode 100644
index 000000000000..457e601e0467
--- /dev/null
+++ b/Documentation/filesystems/erofs.txt
@@ -0,0 +1,225 @@
+Overview
+========
+
+EROFS file-system stands for Enhanced Read-Only File System. Different
+from other read-only file systems, it aims to be designed for flexibility,
+scalability, but be kept simple and high performance.
+
+It is designed as a better filesystem solution for the following scenarios:
+ - read-only storage media or
+
+ - part of a fully trusted read-only solution, which means it needs to be
+   immutable and bit-for-bit identical to the official golden image for
+   their releases due to security and other considerations and
+
+ - hope to save some extra storage space with guaranteed end-to-end performance
+   by using reduced metadata and transparent file compression, especially
+   for those embedded devices with limited memory (ex, smartphone);
+
+Here is the main features of EROFS:
+ - Little endian on-disk design;
+
+ - Currently 4KB block size (nobh) and therefore maximum 16TB address space;
+
+ - Metadata & data could be mixed by design;
+
+ - 2 inode versions for different requirements:
+                          v1            v2
+   Inode metadata size:   32 bytes      64 bytes
+   Max file size:         4 GB          16 EB (also limited by max. vol size)
+   Max uids/gids:         65536         4294967296
+   File creation time:    no            yes (64 + 32-bit timestamp)
+   Max hardlinks:         65536         4294967296
+   Metadata reserved:     4 bytes       14 bytes
+
+ - Support extended attributes (xattrs) as an option;
+
+ - Support xattr inline and tail-end data inline for all files;
+
+ - Support POSIX.1e ACLs by using xattrs;
+
+ - Support statx();
+
+ - Support transparent file compression as an option:
+   LZ4 algorithm with 4 KB fixed-output compression for high performance;
+
+The following git tree provides the file system user-space tools under
+development (ex, formatting tool mkfs.erofs):
+>> git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs-utils.git
+
+Bugs and patches are welcome, please kindly help us and send to the following
+linux-erofs mailing list:
+>> linux-erofs mailing list   <linux-erofs@lists.ozlabs.org>
+
+Note that EROFS is still working in progress as a Linux staging driver,
+Cc the staging mailing list as well is highly recommended:
+>> Linux Driver Project Developer List <devel@driverdev.osuosl.org>
+
+Mount options
+=============
+
+fault_injection=%d     Enable fault injection in all supported types with
+                       specified injection rate. Supported injection type:
+                       Type_Name                Type_Value
+                       FAULT_KMALLOC            0x000000001
+                       FAULT_READ_IO            0x000000002
+(no)user_xattr         Setup Extended User Attributes. Note: xattr is enabled
+                       by default if CONFIG_EROFS_FS_XATTR is selected.
+(no)acl                Setup POSIX Access Control List. Note: acl is enabled
+                       by default if CONFIG_EROFS_FS_POSIX_ACL is selected.
+cache_strategy=%s      Select a strategy for cached decompression from now on:
+                         disabled: In-place I/O decompression only;
+                        readahead: Cache the last incomplete compressed physical
+                                   cluster for further reading. It still does
+                                   in-place I/O decompression for the rest
+                                   compressed physical clusters;
+                       readaround: Cache the both ends of incomplete compressed
+                                   physical clusters for further reading.
+                                   It still does in-place I/O decompression
+                                   for the rest compressed physical clusters.
+
+Module parameters
+=================
+use_vmap=[0|1]         Use vmap() instead of vm_map_ram() (default 0).
+
+On-disk details
+===============
+
+Summary
+-------
+Different from other read-only file systems, an EROFS volume is designed
+to be as simple as possible:
+
+                                |-> aligned with the block size
+   ____________________________________________________________
+  | |SB| | ... | Metadata | ... | Data | Metadata | ... | Data |
+  |_|__|_|_____|__________|_____|______|__________|_____|______|
+  0 +1K
+
+All data areas should be aligned with the block size, but metadata areas
+may not. All metadatas can be now observed in two different spaces (views):
+ 1. Inode metadata space
+    Each valid inode should be aligned with an inode slot, which is a fixed
+    value (32 bytes) and designed to be kept in line with v1 inode size.
+
+    Each inode can be directly found with the following formula:
+         inode offset = meta_blkaddr * block_size + 32 * nid
+
+                                |-> aligned with 8B
+                                           |-> followed closely
+    + meta_blkaddr blocks                                      |-> another slot
+     _____________________________________________________________________
+    |  ...   | inode |  xattrs  | extents  | data inline | ... | inode ...
+    |________|_______|(optional)|(optional)|__(optional)_|_____|__________
+             |-> aligned with the inode slot size
+                  .                   .
+                .                         .
+              .                              .
+            .                                    .
+          .                                         .
+        .                                              .
+      .____________________________________________________|-> aligned with 4B
+      | xattr_ibody_header | shared xattrs | inline xattrs |
+      |____________________|_______________|_______________|
+      |->    12 bytes    <-|->x * 4 bytes<-|               .
+                          .                .                 .
+                    .                      .                   .
+               .                           .                     .
+           ._______________________________.______________________.
+           | id | id | id | id |  ... | id | ent | ... | ent| ... |
+           |____|____|____|____|______|____|_____|_____|____|_____|
+                                           |-> aligned with 4B
+                                                       |-> aligned with 4B
+
+    Inode could be 32 or 64 bytes, which can be distinguished from a common
+    field which all inode versions have -- i_advise:
+
+        __________________               __________________
+       |     i_advise     |             |     i_advise     |
+       |__________________|             |__________________|
+       |        ...       |             |        ...       |
+       |                  |             |                  |
+       |__________________| 32 bytes    |                  |
+                                        |                  |
+                                        |__________________| 64 bytes
+
+    Xattrs, extents, data inline are followed by the corresponding inode with
+    proper alignes, and they could be optional for different data mappings,
+    _currently_ there are totally 3 valid data mappings supported:
+
+     1) flat file data without data inline (no extent);
+     2) fixed-output size data compression (must have extents);
+     3) flat file data with tail-end data inline (no extent);
+
+    The size of the optional xattrs is indicated by i_xattr_count in inode
+    header. Large xattrs or xattrs shared by many different files can be
+    stored in shared xattrs metadata rather than inlined right after inode.
+
+ 2. Shared xattrs metadata space
+    Shared xattrs space is similar to the above inode space, started with
+    a specific block indicated by xattr_blkaddr, organized one by one with
+    proper align.
+
+    Each share xattr can also be directly found by the following formula:
+         xattr offset = xattr_blkaddr * block_size + 4 * xattr_id
+
+                           |-> aligned by  4 bytes
+    + xattr_blkaddr blocks                     |-> aligned with 4 bytes
+     _________________________________________________________________________
+    |  ...   | xattr_entry |  xattr data | ... |  xattr_entry | xattr data  ...
+    |________|_____________|_____________|_____|______________|_______________
+
+Directories
+-----------
+All directories are now organized in a compact on-disk format. Note that
+each directory block is divided into index and name areas in order to support
+random file lookup, and all directory entries are _strictly_ recorded in
+alphabetical order in order to support improved prefix binary search
+algorithm (could refer to the related source code).
+
+                 ___________________________
+                /                           |
+               /              ______________|________________
+              /              /              | nameoff1       | nameoffN-1
+ ____________.______________._______________v________________v__________
+| dirent | dirent | ... | dirent | filename | filename | ... | filename |
+|___.0___|____1___|_____|___N-1__|____0_____|____1_____|_____|___N-1____|
+     \                           ^
+      \                          |                           * could have
+       \                         |                             trailing '\0'
+        \________________________| nameoff0
+
+                             Directory block
+
+Note that apart from the offset of the first filename, nameoff0 also indicates
+the total number of directory entries in this block since it is no need to
+introduce another on-disk field at all.
+
+Compression
+-----------
+Currently, EROFS supports 4KB fixed-output clustersize transparent file
+compression, as illustrated below:
+
+         |---- Variant-Length Extent ----|-------- VLE --------|----- VLE -----
+         clusterofs                      clusterofs            clusterofs
+         |                               |                     |   logical data
+_________v_______________________________v_____________________v_______________
+... |    .        |             |        .    |             |  .          | ...
+____|____.________|_____________|________.____|_____________|__.__________|____
+    |-> cluster <-|-> cluster <-|-> cluster <-|-> cluster <-|-> cluster <-|
+         size          size          size          size          size
+          .                             .                .                   .
+           .                       .               .                  .
+            .                  .              .                .
+      _______._____________._____________._____________._____________________
+         ... |             |             |             | ... physical data
+      _______|_____________|_____________|_____________|_____________________
+             |-> cluster <-|-> cluster <-|-> cluster <-|
+                  size          size          size
+
+Currently each on-disk physical cluster can contain 4KB (un)compressed data
+at most. For each logical cluster, there is a corresponding on-disk index to
+describe its cluster type, physical cluster address, etc.
+
+See "struct z_erofs_vle_decompressed_index" in erofs_fs.h for more details.
+
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 01/24] erofs: add on-disk layout
  2019-08-02 12:53 ` [PATCH v6 01/24] erofs: add on-disk layout Gao Xiang
@ 2019-08-29  9:59   ` Christoph Hellwig
  2019-08-29 10:32     ` Gao Xiang
                       ` (3 more replies)
  0 siblings, 4 replies; 159+ messages in thread
From: Christoph Hellwig @ 2019-08-29  9:59 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds,
	linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei

> --- /dev/null
> +++ b/fs/erofs/erofs_fs.h
> @@ -0,0 +1,316 @@
> +/* SPDX-License-Identifier: GPL-2.0-only OR Apache-2.0 */
> +/*
> + * linux/fs/erofs/erofs_fs.h

Please remove the pointless file names in the comment headers.

> +struct erofs_super_block {
> +/*  0 */__le32 magic;           /* in the little endian */
> +/*  4 */__le32 checksum;        /* crc32c(super_block) */
> +/*  8 */__le32 features;        /* (aka. feature_compat) */
> +/* 12 */__u8 blkszbits;         /* support block_size == PAGE_SIZE only */

Please remove all the byte offset comments.  That is something that can
easily be checked with gdb or pahole.

> +/* 64 */__u8 volume_name[16];   /* volume name */
> +/* 80 */__le32 requirements;    /* (aka. feature_incompat) */
> +
> +/* 84 */__u8 reserved2[44];
> +} __packed;                     /* 128 bytes */

Please don't add __packed.  In this case I think you don't need it
(but double check with pahole), but even if you would need it using
proper padding fields and making sure all fields are naturally aligned
will give you much better code generation on architectures that don't
support native unaligned access.

> +/*
> + * erofs inode data mapping:
> + * 0 - inode plain without inline data A:
> + * inode, [xattrs], ... | ... | no-holed data
> + * 1 - inode VLE compression B (legacy):
> + * inode, [xattrs], extents ... | ...
> + * 2 - inode plain with inline data C:
> + * inode, [xattrs], last_inline_data, ... | ... | no-holed data
> + * 3 - inode compression D:
> + * inode, [xattrs], map_header, extents ... | ...
> + * 4~7 - reserved
> + */
> +enum {
> +	EROFS_INODE_FLAT_PLAIN,

This one doesn't actually seem to be used.

> +	EROFS_INODE_FLAT_COMPRESSION_LEGACY,

why are we adding a legacy field to a brand new file system?

> +	EROFS_INODE_FLAT_INLINE,
> +	EROFS_INODE_FLAT_COMPRESSION,
> +	EROFS_INODE_LAYOUT_MAX

It seems like these come from the on-disk format, in which case they
should have explicit values assigned to them.

Btw, I think it generally helps file system implementation quality
if you use a separate header for the on-disk structures vs in-memory
structures, as that keeps it clear in everyones mind what needs to
stay persistent and what can be chenged easily.

> +static bool erofs_inode_is_data_compressed(unsigned int datamode)
> +{
> +	if (datamode == EROFS_INODE_FLAT_COMPRESSION)
> +		return true;
> +	return datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY;
> +}

This looks like a really obsfucated way to write:

	return datamode == EROFS_INODE_FLAT_COMPRESSION ||
		datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY;

> +/* 28 */__le32 i_reserved2;
> +} __packed;

Sane comment as above.

> +
> +/* 32 bytes on-disk inode */
> +#define EROFS_INODE_LAYOUT_V1   0
> +/* 64 bytes on-disk inode */
> +#define EROFS_INODE_LAYOUT_V2   1
> +
> +struct erofs_inode_v2 {
> +/*  0 */__le16 i_advise;

Why do we have two inode version in a newly added file system?

> +#define ondisk_xattr_ibody_size(count)	({\
> +	u32 __count = le16_to_cpu(count); \
> +	((__count) == 0) ? 0 : \
> +	sizeof(struct erofs_xattr_ibody_header) + \
> +		sizeof(__u32) * ((__count) - 1); })

This would be much more readable as a function.

> +#define EROFS_XATTR_ENTRY_SIZE(entry) EROFS_XATTR_ALIGN( \
> +	sizeof(struct erofs_xattr_entry) + \
> +	(entry)->e_name_len + le16_to_cpu((entry)->e_value_size))

Same here.

> +/* available compression algorithm types */
> +enum {
> +	Z_EROFS_COMPRESSION_LZ4,
> +	Z_EROFS_COMPRESSION_MAX
> +};

Seems like an on-disk value again that should use explicitly assigned
numbers.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 03/24] erofs: add super block operations
  2019-08-02 12:53 ` [PATCH v6 03/24] erofs: add super block operations Gao Xiang
@ 2019-08-29 10:15   ` Christoph Hellwig
  2019-08-29 10:50     ` Gao Xiang
  2019-09-01  8:54     ` Gao Xiang
  0 siblings, 2 replies; 159+ messages in thread
From: Christoph Hellwig @ 2019-08-29 10:15 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds,
	linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei

On Fri, Aug 02, 2019 at 08:53:26PM +0800, Gao Xiang wrote:
> +static int __init erofs_init_inode_cache(void)
> +{
> +	erofs_inode_cachep = kmem_cache_create("erofs_inode",
> +					       sizeof(struct erofs_vnode), 0,
> +					       SLAB_RECLAIM_ACCOUNT,
> +					       init_once);
> +
> +	return erofs_inode_cachep ? 0 : -ENOMEM;

Please just use normal if/else.  Also having this function seems
entirely pointless.

> +static void erofs_exit_inode_cache(void)
> +{
> +	kmem_cache_destroy(erofs_inode_cachep);
> +}

Same for this one.

> +static void free_inode(struct inode *inode)

Please use an erofs_ prefix for all your functions.

> +{
> +	struct erofs_vnode *vi = EROFS_V(inode);

Why is this called vnode instead of inode?  That seems like a rather
odd naming for a Linux file system.

> +
> +	/* be careful RCU symlink path (see ext4_inode_info->i_data)! */
> +	if (is_inode_fast_symlink(inode))
> +		kfree(inode->i_link);

is_inode_fast_symlink only shows up in a later patch.  And really
obsfucates the check here in the only caller as you can just do an
unconditional kfree here - i_link will be NULL except for the case
where you explicitly set it.

Also this code is nothing like ext4, so the code seems a little confusing.

> +static bool check_layout_compatibility(struct super_block *sb,
> +				       struct erofs_super_block *layout)
> +{
> +	const unsigned int requirements = le32_to_cpu(layout->requirements);

Why is the variable name for the on-disk subperblock layout?  We usually
still calls this something with sb in the name, e.g. dsb. for disk
super block.

> +	EROFS_SB(sb)->requirements = requirements;
> +
> +	/* check if current kernel meets all mandatory requirements */
> +	if (requirements & (~EROFS_ALL_REQUIREMENTS)) {
> +		errln("unidentified requirements %x, please upgrade kernel version",
> +		      requirements & ~EROFS_ALL_REQUIREMENTS);
> +		return false;
> +	}
> +	return true;

Note that normally we call this features, but that doesn't really
matter too much.

> +static int superblock_read(struct super_block *sb)
> +{
> +	struct erofs_sb_info *sbi;
> +	struct buffer_head *bh;
> +	struct erofs_super_block *layout;
> +	unsigned int blkszbits;
> +	int ret;
> +
> +	bh = sb_bread(sb, 0);

Is there any good reasons to use buffer heads like this in new code
vs directly using bios?

> +
> +	sbi->blocks = le32_to_cpu(layout->blocks);
> +	sbi->meta_blkaddr = le32_to_cpu(layout->meta_blkaddr);
> +	sbi->islotbits = ffs(sizeof(struct erofs_inode_v1)) - 1;
> +	sbi->root_nid = le16_to_cpu(layout->root_nid);
> +	sbi->inos = le64_to_cpu(layout->inos);
> +
> +	sbi->build_time = le64_to_cpu(layout->build_time);
> +	sbi->build_time_nsec = le32_to_cpu(layout->build_time_nsec);
> +
> +	memcpy(&sb->s_uuid, layout->uuid, sizeof(layout->uuid));
> +	memcpy(sbi->volume_name, layout->volume_name,
> +	       sizeof(layout->volume_name));

s_uuid should preferably be a uuid_t (assuming it is a real BE uuid,
if it is le it should be a guid_t).

> +/* set up default EROFS parameters */
> +static void default_options(struct erofs_sb_info *sbi)
> +{
> +}

No need to add an empty function.

> +static int erofs_fill_super(struct super_block *sb, void *data, int silent)
> +{
> +	struct inode *inode;
> +	struct erofs_sb_info *sbi;
> +	int err;
> +
> +	infoln("fill_super, device -> %s", sb->s_id);
> +	infoln("options -> %s", (char *)data);

That is some very verbose debug info.  We usually don't add that and
let people trace the function instead.  Also you should probably
implement the new mount API.
new mount API.

> +static void erofs_kill_sb(struct super_block *sb)
> +{
> +	struct erofs_sb_info *sbi;
> +
> +	WARN_ON(sb->s_magic != EROFS_SUPER_MAGIC);
> +	infoln("unmounting for %s", sb->s_id);
> +
> +	kill_block_super(sb);
> +
> +	sbi = EROFS_SB(sb);
> +	if (!sbi)
> +		return;
> +	kfree(sbi);
> +	sb->s_fs_info = NULL;
> +}

Why is this needed?  You can just free your sb privatte information in
->put_super and wire up kill_block_super as the ->kill_sb method
directly.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 04/24] erofs: add raw address_space operations
  2019-08-02 12:53 ` [PATCH v6 04/24] erofs: add raw address_space operations Gao Xiang
@ 2019-08-29 10:17   ` Christoph Hellwig
  2019-08-29 11:46     ` Gao Xiang
  0 siblings, 1 reply; 159+ messages in thread
From: Christoph Hellwig @ 2019-08-29 10:17 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds,
	linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei

The actual address_space operations seem to largely duplicate
the iomap versions.  Please use those instead.  Also I don't think
any new file system should write up ->bmap these days.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 05/24] erofs: add inode operations
  2019-08-02 12:53 ` [PATCH v6 05/24] erofs: add inode operations Gao Xiang
@ 2019-08-29 10:24   ` Christoph Hellwig
  2019-08-29 11:59     ` Gao Xiang
  2019-09-01  9:34     ` Gao Xiang
  0 siblings, 2 replies; 159+ messages in thread
From: Christoph Hellwig @ 2019-08-29 10:24 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds,
	linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei

On Fri, Aug 02, 2019 at 08:53:28PM +0800, Gao Xiang wrote:
> This adds core functions to get, read an inode.
> It adds statx support as well.
> 
> Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
> ---
>  fs/erofs/inode.c | 291 +++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 291 insertions(+)
>  create mode 100644 fs/erofs/inode.c
> 
> diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
> new file mode 100644
> index 000000000000..b6ea997bc4ae
> --- /dev/null
> +++ b/fs/erofs/inode.c
> @@ -0,0 +1,291 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * linux/fs/erofs/inode.c
> + *
> + * Copyright (C) 2017-2018 HUAWEI, Inc.
> + *             http://www.huawei.com/
> + * Created by Gao Xiang <gaoxiang25@huawei.com>
> + */
> +#include "internal.h"
> +
> +#include <trace/events/erofs.h>
> +
> +/* no locking */
> +static int read_inode(struct inode *inode, void *data)
> +{
> +	struct erofs_vnode *vi = EROFS_V(inode);
> +	struct erofs_inode_v1 *v1 = data;
> +	const unsigned int advise = le16_to_cpu(v1->i_advise);
> +	erofs_blk_t nblks = 0;
> +
> +	vi->datamode = __inode_data_mapping(advise);

What is the deal with these magic underscores here and various
other similar helpers?

> +	/* fast symlink (following ext4) */

This actually originates in FFS.  But it is so common that the comment
seems a little pointless.

> +	if (S_ISLNK(inode->i_mode) && inode->i_size < PAGE_SIZE) {
> +		char *lnk = erofs_kmalloc(sbi, inode->i_size + 1, GFP_KERNEL);

Please just use plain kmalloc everywhere and let the normal kernel
error injection code take care of injeting any errors.

> +		/* inline symlink data shouldn't across page boundary as well */

... should not cross ..

> +		if (unlikely(m_pofs + inode->i_size > PAGE_SIZE)) {
> +			DBG_BUGON(1);
> +			kfree(lnk);
> +			return -EIO;
> +		}
> +
> +		/* get in-page inline data */

s/get/copy/, but the comment seems rather pointless.

> +		memcpy(lnk, data + m_pofs, inode->i_size);
> +		lnk[inode->i_size] = '\0';
> +
> +		inode->i_link = lnk;
> +		set_inode_fast_symlink(inode);

Please just set the ops directly instead of obsfucating that in a single
caller, single line inline function.  And please set it instead of the
normal symlink iops in the same place where you also set those.:w

> +	err = read_inode(inode, data + ofs);
> +	if (!err) {

	if (err)
		goto out_unlock;

.. and save one level of indentation.

> +		if (is_inode_layout_compression(inode)) {

The name of this helper is a little odd.  But I think just
opencoding it seems generally cleaner anyway.


> +			err = -ENOTSUPP;
> +			goto out_unlock;
> +		}
> +
> +		inode->i_mapping->a_ops = &erofs_raw_access_aops;
> +
> +		/* fill last page if inline data is available */
> +		err = fill_inline_data(inode, data, ofs);

Well, I think you should move the is_inode_flat_inline and
(S_ISLNK(inode->i_mode) && inode->i_size < PAGE_SIZE) checks from that
helper here, as otherwise you make everyone wonder why you'd always
fill out the inline data.

> +static inline struct inode *erofs_iget_locked(struct super_block *sb,
> +					      erofs_nid_t nid)
> +{
> +	const unsigned long hashval = erofs_inode_hash(nid);
> +
> +#if BITS_PER_LONG >= 64
> +	/* it is safe to use iget_locked for >= 64-bit platform */
> +	return iget_locked(sb, hashval);
> +#else
> +	return iget5_locked(sb, hashval, erofs_ilookup_test_actor,
> +		erofs_iget_set_actor, &nid);
> +#endif

Just use the slightly more complicated 32-bit version everywhere so that
you have a single actually tested code path.  And then remove this
helper.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 06/24] erofs: support special inode
  2019-08-02 12:53 ` [PATCH v6 06/24] erofs: support special inode Gao Xiang
@ 2019-08-29 10:25   ` Christoph Hellwig
  2019-09-01  9:39     ` Gao Xiang
  0 siblings, 1 reply; 159+ messages in thread
From: Christoph Hellwig @ 2019-08-29 10:25 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds,
	linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei

On Fri, Aug 02, 2019 at 08:53:29PM +0800, Gao Xiang wrote:
> This patch adds to support special inode, such as
> block dev, char, socket, pipe inode.
> 
> Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
> ---
>  fs/erofs/inode.c | 27 +++++++++++++++++++++++++--
>  1 file changed, 25 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
> index b6ea997bc4ae..637bf6e4de44 100644
> --- a/fs/erofs/inode.c
> +++ b/fs/erofs/inode.c
> @@ -34,7 +34,16 @@ static int read_inode(struct inode *inode, void *data)
>  		vi->xattr_isize = ondisk_xattr_ibody_size(v2->i_xattr_icount);
>  
>  		inode->i_mode = le16_to_cpu(v2->i_mode);
> -		vi->raw_blkaddr = le32_to_cpu(v2->i_u.raw_blkaddr);
> +		if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
> +		    S_ISLNK(inode->i_mode))
> +			vi->raw_blkaddr = le32_to_cpu(v2->i_u.raw_blkaddr);
> +		else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
> +			inode->i_rdev =
> +				new_decode_dev(le32_to_cpu(v2->i_u.rdev));
> +		else if (S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode))
> +			inode->i_rdev = 0;
> +		else
> +			return -EIO;

Please use a switch statement when dealing with the file modes to
make everything easier to read.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 08/24] erofs: add namei functions
  2019-08-02 12:53 ` [PATCH v6 08/24] erofs: add namei functions Gao Xiang
@ 2019-08-29 10:28   ` Christoph Hellwig
  2019-08-29 11:28     ` Gao Xiang
  0 siblings, 1 reply; 159+ messages in thread
From: Christoph Hellwig @ 2019-08-29 10:28 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Christoph Hellwig, Darrick J . Wong,
	Dave Chinner, Jaegeuk Kim, Jan Kara, Linus Torvalds,
	linux-fsdevel, devel, LKML, linux-erofs, Chao Yu, Miao Xie,
	Li Guifu, Fang Wei

On Fri, Aug 02, 2019 at 08:53:31PM +0800, Gao Xiang wrote:
> +struct erofs_qstr {
> +	const unsigned char *name;
> +	const unsigned char *end;
> +};

Maybe erofs_name?  The q in qstr stands for quick, because of the
existing hash and len, which this doesn't really provide.

Also I don't really see why you don't just pass the actual qstr and
just document that dirnamecmp does not look at the hash and thus
doesn't require it to be filled out.


^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 01/24] erofs: add on-disk layout
  2019-08-29  9:59   ` Christoph Hellwig
@ 2019-08-29 10:32     ` Gao Xiang
  2019-08-29 10:36       ` Christoph Hellwig
  2019-08-29 15:58       ` Joe Perches
  2019-08-29 15:41     ` Gao Xiang
                       ` (2 subsequent siblings)
  3 siblings, 2 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-29 10:32 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Darrick J . Wong, Dave Chinner, Jaegeuk Kim,
	Jan Kara, Linus Torvalds, linux-fsdevel, devel, LKML,
	linux-erofs, Chao Yu, Miao Xie, Li Guifu, Fang Wei

Hi Christoph,

On Thu, Aug 29, 2019 at 02:59:54AM -0700, Christoph Hellwig wrote:
> > --- /dev/null
> > +++ b/fs/erofs/erofs_fs.h
> > @@ -0,0 +1,316 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only OR Apache-2.0 */
> > +/*
> > + * linux/fs/erofs/erofs_fs.h
> 
> Please remove the pointless file names in the comment headers.

Already removed in the latest version.

> 
> > +struct erofs_super_block {
> > +/*  0 */__le32 magic;           /* in the little endian */
> > +/*  4 */__le32 checksum;        /* crc32c(super_block) */
> > +/*  8 */__le32 features;        /* (aka. feature_compat) */
> > +/* 12 */__u8 blkszbits;         /* support block_size == PAGE_SIZE only */
> 
> Please remove all the byte offset comments.  That is something that can
> easily be checked with gdb or pahole.

I have no idea the actual issue here.
It will help all developpers better add fields or calculate
these offsets in their mind, and with care.

Rather than they didn't run "gdb" or "pahole" and change it by mistake.

> 
> > +/* 64 */__u8 volume_name[16];   /* volume name */
> > +/* 80 */__le32 requirements;    /* (aka. feature_incompat) */
> > +
> > +/* 84 */__u8 reserved2[44];
> > +} __packed;                     /* 128 bytes */
> 
> Please don't add __packed.  In this case I think you don't need it
> (but double check with pahole), but even if you would need it using
> proper padding fields and making sure all fields are naturally aligned
> will give you much better code generation on architectures that don't
> support native unaligned access.

If you can see more, all on-disk fields in EROFS are naturally aligned,
I can remove all of these as you like, but I think that is not very urgent.

> 
> > +/*
> > + * erofs inode data mapping:
> > + * 0 - inode plain without inline data A:
> > + * inode, [xattrs], ... | ... | no-holed data
> > + * 1 - inode VLE compression B (legacy):
> > + * inode, [xattrs], extents ... | ...
> > + * 2 - inode plain with inline data C:
> > + * inode, [xattrs], last_inline_data, ... | ... | no-holed data
> > + * 3 - inode compression D:
> > + * inode, [xattrs], map_header, extents ... | ...
> > + * 4~7 - reserved
> > + */
> > +enum {
> > +	EROFS_INODE_FLAT_PLAIN,
> 
> This one doesn't actually seem to be used.

It could be better has a name though, because erofs.mkfs uses it,
and we keep this on-disk file up with erofs-utils.

> 
> > +	EROFS_INODE_FLAT_COMPRESSION_LEGACY,
> 
> why are we adding a legacy field to a brand new file system?

the difference is just EROFS_INODE_FLAT_COMPRESSION_LEGACY doesn't have
z_erofs_map_header, nothing special at all.

> 
> > +	EROFS_INODE_FLAT_INLINE,
> > +	EROFS_INODE_FLAT_COMPRESSION,
> > +	EROFS_INODE_LAYOUT_MAX
> 
> It seems like these come from the on-disk format, in which case they
> should have explicit values assigned to them.
> 
> Btw, I think it generally helps file system implementation quality
> if you use a separate header for the on-disk structures vs in-memory
> structures, as that keeps it clear in everyones mind what needs to
> stay persistent and what can be chenged easily.

All fields in this file are on-disk representation.

> 
> > +static bool erofs_inode_is_data_compressed(unsigned int datamode)
> > +{
> > +	if (datamode == EROFS_INODE_FLAT_COMPRESSION)
> > +		return true;
> > +	return datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY;
> > +}
> 
> This looks like a really obsfucated way to write:
> 
> 	return datamode == EROFS_INODE_FLAT_COMPRESSION ||
> 		datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY;

It depends on the personal choise, if you like, I will change into your form.

> 
> > +/* 28 */__le32 i_reserved2;
> > +} __packed;
> 
> Sane comment as above.
> 
> > +
> > +/* 32 bytes on-disk inode */
> > +#define EROFS_INODE_LAYOUT_V1   0
> > +/* 64 bytes on-disk inode */
> > +#define EROFS_INODE_LAYOUT_V2   1
> > +
> > +struct erofs_inode_v2 {
> > +/*  0 */__le16 i_advise;
> 
> Why do we have two inode version in a newly added file system?

v2 is an exhanced on-disk inode form, it has 64 bytes,
v1 is more compacted one, which is already suitable
for Android use case of course.

There is no new and old, both are used for the current EROFS.

> 
> > +#define ondisk_xattr_ibody_size(count)	({\
> > +	u32 __count = le16_to_cpu(count); \
> > +	((__count) == 0) ? 0 : \
> > +	sizeof(struct erofs_xattr_ibody_header) + \
> > +		sizeof(__u32) * ((__count) - 1); })
> 
> This would be much more readable as a function.
> 
> > +#define EROFS_XATTR_ENTRY_SIZE(entry) EROFS_XATTR_ALIGN( \
> > +	sizeof(struct erofs_xattr_entry) + \
> > +	(entry)->e_name_len + le16_to_cpu((entry)->e_value_size))
> 
> Same here.

Personal tendency, because we are working in a dedicated team rather than
an individual person.

But I can fix as you like.

> 
> > +/* available compression algorithm types */
> > +enum {
> > +	Z_EROFS_COMPRESSION_LZ4,
> > +	Z_EROFS_COMPRESSION_MAX
> > +};
> 
> Seems like an on-disk value again that should use explicitly assigned
> numbers.

I can fix it up as you like but I still cannot get
what is critical issues here.

Thanks,
Gao Xiang



^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 01/24] erofs: add on-disk layout
  2019-08-29 10:32     ` Gao Xiang
@ 2019-08-29 10:36       ` Christoph Hellwig
  2019-08-29 10:58         ` Gao Xiang
  2019-08-29 15:58       ` Joe Perches
  1 sibling, 1 reply; 159+ messages in thread
From: Christoph Hellwig @ 2019-08-29 10:36 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Alexander Viro, Greg Kroah-Hartman,
	Andrew Morton, Stephen Rothwell, Theodore Ts'o, Pavel Machek,
	David Sterba, Amir Goldstein, Darrick J . Wong, Dave Chinner,
	Jaegeuk Kim, Jan Kara, Linus Torvalds, linux-fsdevel, devel,
	LKML, linux-erofs, Chao Yu, Miao Xie, Li Guifu, Fang Wei

On Thu, Aug 29, 2019 at 06:32:53PM +0800, Gao Xiang wrote:
> I can fix it up as you like but I still cannot get
> what is critical issues here.

The problem is that the whole codebase is way substandard quality,
looking a lot like Linux code from 20 years ago.  Yes, we already have
plenty of code of that standard in the tree, but we should not add more.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 03/24] erofs: add super block operations
  2019-08-29 10:15   ` Christoph Hellwig
@ 2019-08-29 10:50     ` Gao Xiang
  2019-08-30 16:39       ` Christoph Hellwig
  2019-09-01  8:54     ` Gao Xiang
  1 sibling, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-08-29 10:50 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Darrick J . Wong, Dave Chinner, Jaegeuk Kim,
	Jan Kara, Linus Torvalds, linux-fsdevel, devel, LKML,
	linux-erofs, Chao Yu, Miao Xie, Li Guifu, Fang Wei

Hi Christoph,

On Thu, Aug 29, 2019 at 03:15:45AM -0700, Christoph Hellwig wrote:
> On Fri, Aug 02, 2019 at 08:53:26PM +0800, Gao Xiang wrote:
> > +static int __init erofs_init_inode_cache(void)
> > +{
> > +	erofs_inode_cachep = kmem_cache_create("erofs_inode",
> > +					       sizeof(struct erofs_vnode), 0,
> > +					       SLAB_RECLAIM_ACCOUNT,
> > +					       init_once);
> > +
> > +	return erofs_inode_cachep ? 0 : -ENOMEM;
> 
> Please just use normal if/else.  Also having this function seems
> entirely pointless.
> 
> > +static void erofs_exit_inode_cache(void)
> > +{
> > +	kmem_cache_destroy(erofs_inode_cachep);
> > +}
> 
> Same for this one.
> 
> > +static void free_inode(struct inode *inode)
> 
> Please use an erofs_ prefix for all your functions.

It is already a static function, I have no idea what is wrong here.

> 
> > +{
> > +	struct erofs_vnode *vi = EROFS_V(inode);
> 
> Why is this called vnode instead of inode?  That seems like a rather
> odd naming for a Linux file system.

I don't know anything difference of that, it is just a naming.

> 
> > +
> > +	/* be careful RCU symlink path (see ext4_inode_info->i_data)! */
> > +	if (is_inode_fast_symlink(inode))
> > +		kfree(inode->i_link);
> 
> is_inode_fast_symlink only shows up in a later patch.  And really
> obsfucates the check here in the only caller as you can just do an
> unconditional kfree here - i_link will be NULL except for the case
> where you explicitly set it.

I cannot fully understand your point (sorry about my English),
I will reply you about this later.

> 
> Also this code is nothing like ext4, so the code seems a little confusing.
> 
> > +static bool check_layout_compatibility(struct super_block *sb,
> > +				       struct erofs_super_block *layout)
> > +{
> > +	const unsigned int requirements = le32_to_cpu(layout->requirements);
> 
> Why is the variable name for the on-disk subperblock layout?  We usually
> still calls this something with sb in the name, e.g. dsb. for disk
> super block.

I can change it later, sbi and dsb (It has not good meaning in Chinese, although).

> 
> > +	EROFS_SB(sb)->requirements = requirements;
> > +
> > +	/* check if current kernel meets all mandatory requirements */
> > +	if (requirements & (~EROFS_ALL_REQUIREMENTS)) {
> > +		errln("unidentified requirements %x, please upgrade kernel version",
> > +		      requirements & ~EROFS_ALL_REQUIREMENTS);
> > +		return false;
> > +	}
> > +	return true;
> 
> Note that normally we call this features, but that doesn't really
> matter too much.
> 
> > +static int superblock_read(struct super_block *sb)
> > +{
> > +	struct erofs_sb_info *sbi;
> > +	struct buffer_head *bh;
> > +	struct erofs_super_block *layout;
> > +	unsigned int blkszbits;
> > +	int ret;
> > +
> > +	bh = sb_bread(sb, 0);
> 
> Is there any good reasons to use buffer heads like this in new code
> vs directly using bios?

This page can save in bdev page cache, it contains not only the erofs
superblock so it can be fetched in page cache later.

> 
> > +
> > +	sbi->blocks = le32_to_cpu(layout->blocks);
> > +	sbi->meta_blkaddr = le32_to_cpu(layout->meta_blkaddr);
> > +	sbi->islotbits = ffs(sizeof(struct erofs_inode_v1)) - 1;
> > +	sbi->root_nid = le16_to_cpu(layout->root_nid);
> > +	sbi->inos = le64_to_cpu(layout->inos);
> > +
> > +	sbi->build_time = le64_to_cpu(layout->build_time);
> > +	sbi->build_time_nsec = le32_to_cpu(layout->build_time_nsec);
> > +
> > +	memcpy(&sb->s_uuid, layout->uuid, sizeof(layout->uuid));
> > +	memcpy(sbi->volume_name, layout->volume_name,
> > +	       sizeof(layout->volume_name));
> 
> s_uuid should preferably be a uuid_t (assuming it is a real BE uuid,
> if it is le it should be a guid_t).

I just copied it from f2fs, I have no idea which one is best and
which fs I could refer to.

> 
> > +/* set up default EROFS parameters */
> > +static void default_options(struct erofs_sb_info *sbi)
> > +{
> > +}
> 
> No need to add an empty function.

Later patch will fill this function.

> 
> > +static int erofs_fill_super(struct super_block *sb, void *data, int silent)
> > +{
> > +	struct inode *inode;
> > +	struct erofs_sb_info *sbi;
> > +	int err;
> > +
> > +	infoln("fill_super, device -> %s", sb->s_id);
> > +	infoln("options -> %s", (char *)data);
> 
> That is some very verbose debug info.  We usually don't add that and
> let people trace the function instead.  Also you should probably
> implement the new mount API.
> new mount API.

Al think it is not urgent as well,
https://lore.kernel.org/driverdev-devel/20190721040547.GF17978@ZenIV.linux.org.uk/

 Al said,
 >> I agree with you, it seems better to just use s_id in community and
 >> delete erofs_mount_private stuffs...
 >> Yet I don't look into how to use new fs_context, could I keep using
 >> legacy mount interface and fix them all?
 >
 > Sure.

> 
> > +static void erofs_kill_sb(struct super_block *sb)
> > +{
> > +	struct erofs_sb_info *sbi;
> > +
> > +	WARN_ON(sb->s_magic != EROFS_SUPER_MAGIC);
> > +	infoln("unmounting for %s", sb->s_id);
> > +
> > +	kill_block_super(sb);
> > +
> > +	sbi = EROFS_SB(sb);
> > +	if (!sbi)
> > +		return;
> > +	kfree(sbi);
> > +	sb->s_fs_info = NULL;
> > +}
> 
> Why is this needed?  You can just free your sb privatte information in
> ->put_super and wire up kill_block_super as the ->kill_sb method
> directly.

See Al's comments,
https://lore.kernel.org/r/20190720224955.GD17978@ZenIV.linux.org.uk/

Thanks,
Gao Xiang


^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 01/24] erofs: add on-disk layout
  2019-08-29 10:36       ` Christoph Hellwig
@ 2019-08-29 10:58         ` Gao Xiang
  0 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-29 10:58 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Darrick J . Wong, Dave Chinner, Jaegeuk Kim,
	Jan Kara, Linus Torvalds, linux-fsdevel, devel, LKML,
	linux-erofs, Chao Yu, Miao Xie, Li Guifu, Fang Wei

Hi Christoph,

On Thu, Aug 29, 2019 at 03:36:04AM -0700, Christoph Hellwig wrote:
> On Thu, Aug 29, 2019 at 06:32:53PM +0800, Gao Xiang wrote:
> > I can fix it up as you like but I still cannot get
> > what is critical issues here.
> 
> The problem is that the whole codebase is way substandard quality,
> looking a lot like Linux code from 20 years ago.  Yes, we already have
> plenty of code of that standard in the tree, but we should not add more.

I still cannot get your point what does your substandard quality mean,
please refer to some thing critical in EROFS (and I noticed that your
new code still has bug) rather than naming.

Thanks,
Gao Xiang


^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 08/24] erofs: add namei functions
  2019-08-29 10:28   ` Christoph Hellwig
@ 2019-08-29 11:28     ` Gao Xiang
  0 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-29 11:28 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Darrick J . Wong, Dave Chinner, Jaegeuk Kim,
	Jan Kara, Linus Torvalds, linux-fsdevel, devel, LKML,
	linux-erofs, Chao Yu, Miao Xie, Li Guifu, Fang Wei

On Thu, Aug 29, 2019 at 03:28:38AM -0700, Christoph Hellwig wrote:
> On Fri, Aug 02, 2019 at 08:53:31PM +0800, Gao Xiang wrote:
> > +struct erofs_qstr {
> > +	const unsigned char *name;
> > +	const unsigned char *end;
> > +};
> 
> Maybe erofs_name?  The q in qstr stands for quick, because of the
> existing hash and len, which this doesn't really provide.
> 
> Also I don't really see why you don't just pass the actual qstr and
> just document that dirnamecmp does not look at the hash and thus
> doesn't require it to be filled out.

q in erofs_qstr also means quick substring.
If you have some time to look into it more, it uses a prefixed
binary search algorithm (rather than linear traversal), which
provides similar proformance with hashed approach but no need
to save such hash field and it's natively sorted in alphabet
order.

Thanks,
Gao Xiang

> 

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 04/24] erofs: add raw address_space operations
  2019-08-29 10:17   ` Christoph Hellwig
@ 2019-08-29 11:46     ` Gao Xiang
  2019-08-30 16:40       ` Christoph Hellwig
  0 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-08-29 11:46 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Darrick J . Wong, Dave Chinner, Jaegeuk Kim,
	Jan Kara, Linus Torvalds, linux-fsdevel, devel, LKML,
	linux-erofs, Chao Yu, Miao Xie, Li Guifu, Fang Wei

Hi Christoph,

On Thu, Aug 29, 2019 at 03:17:21AM -0700, Christoph Hellwig wrote:
> The actual address_space operations seem to largely duplicate
> the iomap versions.  Please use those instead.  Also I don't think
> any new file system should write up ->bmap these days.

iomap doesn't support tail-end packing inline data till now,
I think Chao and I told you and Andreas before [1].

Since EROFS keeps a self-contained driver for now, we will use
iomap if it supports tail-end packing inline data later.

[1] https://lore.kernel.org/linux-fsdevel/90fca1c4-c142-992d-ebf3-03c8017f95b7@huawei.com/

Thanks,
Gao Xiang


^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 05/24] erofs: add inode operations
  2019-08-29 10:24   ` Christoph Hellwig
@ 2019-08-29 11:59     ` Gao Xiang
  2019-08-30 16:42       ` Christoph Hellwig
  2019-09-01  9:34     ` Gao Xiang
  1 sibling, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-08-29 11:59 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Darrick J . Wong, Dave Chinner, Jaegeuk Kim,
	Jan Kara, Linus Torvalds, linux-fsdevel, devel, LKML,
	linux-erofs, Chao Yu, Miao Xie, Li Guifu, Fang Wei

On Thu, Aug 29, 2019 at 03:24:26AM -0700, Christoph Hellwig wrote:

[]

> 
> > +
> > +		/* fill last page if inline data is available */
> > +		err = fill_inline_data(inode, data, ofs);
> 
> Well, I think you should move the is_inode_flat_inline and
> (S_ISLNK(inode->i_mode) && inode->i_size < PAGE_SIZE) checks from that
> helper here, as otherwise you make everyone wonder why you'd always
> fill out the inline data.

Currently, fill_inline_data() only fills for fast symlink,
later we can fill any tail-end block (such as dir block)
for our requirements.

And I think that is minor.

> 
> > +static inline struct inode *erofs_iget_locked(struct super_block *sb,
> > +					      erofs_nid_t nid)
> > +{
> > +	const unsigned long hashval = erofs_inode_hash(nid);
> > +
> > +#if BITS_PER_LONG >= 64
> > +	/* it is safe to use iget_locked for >= 64-bit platform */
> > +	return iget_locked(sb, hashval);
> > +#else
> > +	return iget5_locked(sb, hashval, erofs_ilookup_test_actor,
> > +		erofs_iget_set_actor, &nid);
> > +#endif
> 
> Just use the slightly more complicated 32-bit version everywhere so that
> you have a single actually tested code path.  And then remove this
> helper.

The consideration is simply because iget_locked performs better
than iget5_locked.

Thanks,
Gao Xiang


^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 01/24] erofs: add on-disk layout
  2019-08-29  9:59   ` Christoph Hellwig
  2019-08-29 10:32     ` Gao Xiang
@ 2019-08-29 15:41     ` Gao Xiang
  2019-09-01  7:54     ` Gao Xiang
  2019-09-02  8:40     ` Pavel Machek
  3 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-29 15:41 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Darrick J . Wong, Dave Chinner, Jaegeuk Kim,
	Jan Kara, Linus Torvalds, linux-fsdevel, devel, LKML,
	linux-erofs, Chao Yu, Miao Xie, Li Guifu, Fang Wei

Hi Christoph,

On Thu, Aug 29, 2019 at 02:59:54AM -0700, Christoph Hellwig wrote:

[]

> 
> > +static bool erofs_inode_is_data_compressed(unsigned int datamode)
> > +{
> > +	if (datamode == EROFS_INODE_FLAT_COMPRESSION)
> > +		return true;
> > +	return datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY;
> > +}
> 
> This looks like a really obsfucated way to write:
> 
> 	return datamode == EROFS_INODE_FLAT_COMPRESSION ||
> 		datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY;

Add a word about this, the above approach is not horrible if more
datamode add here and comments, e.g

static bool erofs_inode_is_data_compressed(unsigned int datamode)
{
	/* has z_erofs_map_header */
	if (datamode == EROFS_INODE_FLAT_COMPRESSION)
		return true;
	/* some blablabla */
	if (datamode == (1) )
		return true;
	/* some blablablabla */
	if (datamode == (2) )
		return true;
	/* no z_erofs_map_header */
	return datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY;
}

vs.

static bool erofs_inode_is_data_compressed(unsigned int datamode)
{
	/* has z_erofs_map_header */
	return datamode == EROFS_INODE_FLAT_COMPRESSION ||
		/* some blablabla */
	       datamode == (1) ||
	       	/* some blablablabla */
	       datamode == (2) ||
	        /* no z_erofs_map_header */
	       datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY;
}

I have no idea which one is better.
Anyway, if you still like the form, I will change it.

Thanks,
Gao Xiang

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 01/24] erofs: add on-disk layout
  2019-08-29 10:32     ` Gao Xiang
  2019-08-29 10:36       ` Christoph Hellwig
@ 2019-08-29 15:58       ` Joe Perches
  2019-08-29 17:26         ` Gao Xiang
  2019-08-30 12:07         ` David Sterba
  1 sibling, 2 replies; 159+ messages in thread
From: Joe Perches @ 2019-08-29 15:58 UTC (permalink / raw)
  To: Gao Xiang, Christoph Hellwig
  Cc: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Darrick J . Wong, Dave Chinner, Jaegeuk Kim,
	Jan Kara, Linus Torvalds, linux-fsdevel, devel, LKML,
	linux-erofs, Chao Yu, Miao Xie, Li Guifu, Fang Wei

On Thu, 2019-08-29 at 18:32 +0800, Gao Xiang wrote:
> Hi Christoph,
> 
> On Thu, Aug 29, 2019 at 02:59:54AM -0700, Christoph Hellwig wrote:
> > > --- /dev/null
> > > +++ b/fs/erofs/erofs_fs.h
> > > @@ -0,0 +1,316 @@
> > > +/* SPDX-License-Identifier: GPL-2.0-only OR Apache-2.0 */
> > > +/*
> > > + * linux/fs/erofs/erofs_fs.h
> > 
> > Please remove the pointless file names in the comment headers.
> 
> Already removed in the latest version.
> 
> > > +struct erofs_super_block {
> > > +/*  0 */__le32 magic;           /* in the little endian */
> > > +/*  4 */__le32 checksum;        /* crc32c(super_block) */
> > > +/*  8 */__le32 features;        /* (aka. feature_compat) */
> > > +/* 12 */__u8 blkszbits;         /* support block_size == PAGE_SIZE only */
> > 
> > Please remove all the byte offset comments.  That is something that can
> > easily be checked with gdb or pahole.
> 
> I have no idea the actual issue here.
> It will help all developpers better add fields or calculate
> these offsets in their mind, and with care.
> 
> Rather than they didn't run "gdb" or "pahole" and change it by mistake.

I think Christoph is not right here.

Using external tools for validation is extra work
when necessary for understanding the code.

The expected offset is somewhat valuable, but
perhaps the form is a bit off given the visual
run-in to the field types.

The extra work with this form is manipulating all
the offsets whenever a structure change occurs.

The comments might be better with a form more like:

struct erofs_super_block {	/* offset description */
	__le32 magic;		/*   0  */
	__le32 checksum;	/*   4  crc32c(super_block) */
	__le32 features;	/*   8  (aka. feature_compat) */
	__u8 blkszbits;		/*  12  support block_size == PAGE_SIZE only */



^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 01/24] erofs: add on-disk layout
  2019-08-29 15:58       ` Joe Perches
@ 2019-08-29 17:26         ` Gao Xiang
  2019-08-30 12:07         ` David Sterba
  1 sibling, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-29 17:26 UTC (permalink / raw)
  To: Joe Perches
  Cc: Christoph Hellwig, Alexander Viro, Greg Kroah-Hartman,
	Andrew Morton, Stephen Rothwell, Theodore Ts'o, Pavel Machek,
	David Sterba, Amir Goldstein, Darrick J . Wong, Dave Chinner,
	Jaegeuk Kim, Jan Kara, Linus Torvalds, linux-fsdevel, devel,
	LKML, linux-erofs, Chao Yu, Miao Xie, Li Guifu, Fang Wei

Hi Joe,

On Thu, Aug 29, 2019 at 08:58:17AM -0700, Joe Perches wrote:
> On Thu, 2019-08-29 at 18:32 +0800, Gao Xiang wrote:
> > Hi Christoph,
> > 
> > On Thu, Aug 29, 2019 at 02:59:54AM -0700, Christoph Hellwig wrote:
> > > > --- /dev/null
> > > > +++ b/fs/erofs/erofs_fs.h
> > > > @@ -0,0 +1,316 @@
> > > > +/* SPDX-License-Identifier: GPL-2.0-only OR Apache-2.0 */
> > > > +/*
> > > > + * linux/fs/erofs/erofs_fs.h
> > > 
> > > Please remove the pointless file names in the comment headers.
> > 
> > Already removed in the latest version.
> > 
> > > > +struct erofs_super_block {
> > > > +/*  0 */__le32 magic;           /* in the little endian */
> > > > +/*  4 */__le32 checksum;        /* crc32c(super_block) */
> > > > +/*  8 */__le32 features;        /* (aka. feature_compat) */
> > > > +/* 12 */__u8 blkszbits;         /* support block_size == PAGE_SIZE only */
> > > 
> > > Please remove all the byte offset comments.  That is something that can
> > > easily be checked with gdb or pahole.
> > 
> > I have no idea the actual issue here.
> > It will help all developpers better add fields or calculate
> > these offsets in their mind, and with care.
> > 
> > Rather than they didn't run "gdb" or "pahole" and change it by mistake.
> 
> I think Christoph is not right here.
> 
> Using external tools for validation is extra work
> when necessary for understanding the code.
> 
> The expected offset is somewhat valuable, but
> perhaps the form is a bit off given the visual
> run-in to the field types.
> 
> The extra work with this form is manipulating all
> the offsets whenever a structure change occurs.
> 
> The comments might be better with a form more like:

Thanks for your comment.
I will change those places as you suggested, that is fine.

Thanks,
Gao Xiang

> 
> struct erofs_super_block {	/* offset description */
> 	__le32 magic;		/*   0  */
> 	__le32 checksum;	/*   4  crc32c(super_block) */
> 	__le32 features;	/*   8  (aka. feature_compat) */
> 	__u8 blkszbits;		/*  12  support block_size == PAGE_SIZE only */
> 
> 

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 01/24] erofs: add on-disk layout
  2019-08-29 15:58       ` Joe Perches
  2019-08-29 17:26         ` Gao Xiang
@ 2019-08-30 12:07         ` David Sterba
  2019-08-30 12:18           ` Gao Xiang
  2019-09-02  8:43           ` Pavel Machek
  1 sibling, 2 replies; 159+ messages in thread
From: David Sterba @ 2019-08-30 12:07 UTC (permalink / raw)
  To: Joe Perches
  Cc: Gao Xiang, Christoph Hellwig, Alexander Viro, Greg Kroah-Hartman,
	Andrew Morton, Stephen Rothwell, Theodore Ts'o, Pavel Machek,
	David Sterba, Amir Goldstein, Darrick J . Wong, Dave Chinner,
	Jaegeuk Kim, Jan Kara, Linus Torvalds, linux-fsdevel, devel,
	LKML, linux-erofs, Chao Yu, Miao Xie, Li Guifu, Fang Wei

On Thu, Aug 29, 2019 at 08:58:17AM -0700, Joe Perches wrote:
> On Thu, 2019-08-29 at 18:32 +0800, Gao Xiang wrote:
> > Hi Christoph,
> > 
> > On Thu, Aug 29, 2019 at 02:59:54AM -0700, Christoph Hellwig wrote:
> > > > --- /dev/null
> > > > +++ b/fs/erofs/erofs_fs.h
> > > > @@ -0,0 +1,316 @@
> > > > +/* SPDX-License-Identifier: GPL-2.0-only OR Apache-2.0 */
> > > > +/*
> > > > + * linux/fs/erofs/erofs_fs.h
> > > 
> > > Please remove the pointless file names in the comment headers.
> > 
> > Already removed in the latest version.
> > 
> > > > +struct erofs_super_block {
> > > > +/*  0 */__le32 magic;           /* in the little endian */
> > > > +/*  4 */__le32 checksum;        /* crc32c(super_block) */
> > > > +/*  8 */__le32 features;        /* (aka. feature_compat) */
> > > > +/* 12 */__u8 blkszbits;         /* support block_size == PAGE_SIZE only */
> > > 
> > > Please remove all the byte offset comments.  That is something that can
> > > easily be checked with gdb or pahole.
> > 
> > I have no idea the actual issue here.
> > It will help all developpers better add fields or calculate
> > these offsets in their mind, and with care.
> > 
> > Rather than they didn't run "gdb" or "pahole" and change it by mistake.
> 
> I think Christoph is not right here.
> 
> Using external tools for validation is extra work
> when necessary for understanding the code.

The advantage of using the external tools that the information about
offsets is provably correct ...

> The expected offset is somewhat valuable, but
> perhaps the form is a bit off given the visual
> run-in to the field types.
> 
> The extra work with this form is manipulating all
> the offsets whenever a structure change occurs.

... while this is error prone.

> The comments might be better with a form more like:
> 
> struct erofs_super_block {	/* offset description */
> 	__le32 magic;		/*   0  */
> 	__le32 checksum;	/*   4  crc32c(super_block) */
> 	__le32 features;	/*   8  (aka. feature_compat) */
> 	__u8 blkszbits;		/*  12  support block_size == PAGE_SIZE only */

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 01/24] erofs: add on-disk layout
  2019-08-30 12:07         ` David Sterba
@ 2019-08-30 12:18           ` Gao Xiang
  2019-09-02  8:43           ` Pavel Machek
  1 sibling, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-30 12:18 UTC (permalink / raw)
  To: dsterba, Joe Perches, Gao Xiang, Christoph Hellwig,
	Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek,
	Amir Goldstein, Darrick J . Wong, Dave Chinner, Jaegeuk Kim,
	Jan Kara, Linus Torvalds, linux-fsdevel, devel, LKML,
	linux-erofs, Chao Yu, Miao Xie, Li Guifu, Fang Wei

Hi David,

On Fri, Aug 30, 2019 at 02:07:14PM +0200, David Sterba wrote:
> On Thu, Aug 29, 2019 at 08:58:17AM -0700, Joe Perches wrote:
> > On Thu, 2019-08-29 at 18:32 +0800, Gao Xiang wrote:
> > > Hi Christoph,
> > > 
> > > On Thu, Aug 29, 2019 at 02:59:54AM -0700, Christoph Hellwig wrote:
> > > > > --- /dev/null
> > > > > +++ b/fs/erofs/erofs_fs.h
> > > > > @@ -0,0 +1,316 @@
> > > > > +/* SPDX-License-Identifier: GPL-2.0-only OR Apache-2.0 */
> > > > > +/*
> > > > > + * linux/fs/erofs/erofs_fs.h
> > > > 
> > > > Please remove the pointless file names in the comment headers.
> > > 
> > > Already removed in the latest version.
> > > 
> > > > > +struct erofs_super_block {
> > > > > +/*  0 */__le32 magic;           /* in the little endian */
> > > > > +/*  4 */__le32 checksum;        /* crc32c(super_block) */
> > > > > +/*  8 */__le32 features;        /* (aka. feature_compat) */
> > > > > +/* 12 */__u8 blkszbits;         /* support block_size == PAGE_SIZE only */
> > > > 
> > > > Please remove all the byte offset comments.  That is something that can
> > > > easily be checked with gdb or pahole.
> > > 
> > > I have no idea the actual issue here.
> > > It will help all developpers better add fields or calculate
> > > these offsets in their mind, and with care.
> > > 
> > > Rather than they didn't run "gdb" or "pahole" and change it by mistake.
> > 
> > I think Christoph is not right here.
> > 
> > Using external tools for validation is extra work
> > when necessary for understanding the code.
> 
> The advantage of using the external tools that the information about
> offsets is provably correct ...
> 
> > The expected offset is somewhat valuable, but
> > perhaps the form is a bit off given the visual
> > run-in to the field types.
> > 
> > The extra work with this form is manipulating all
> > the offsets whenever a structure change occurs.
> 
> ... while this is error prone.

I will redo a full patchset and comments addressing
what Christoph all said yesterday.

Either form is fine with me for this case, let's remove
them instead.

Thanks,
Gao Xiang

> 
> > The comments might be better with a form more like:
> > 
> > struct erofs_super_block {	/* offset description */
> > 	__le32 magic;		/*   0  */
> > 	__le32 checksum;	/*   4  crc32c(super_block) */
> > 	__le32 features;	/*   8  (aka. feature_compat) */
> > 	__u8 blkszbits;		/*  12  support block_size == PAGE_SIZE only */


^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 03/24] erofs: add super block operations
  2019-08-29 10:50     ` Gao Xiang
@ 2019-08-30 16:39       ` Christoph Hellwig
  2019-08-30 17:15         ` Gao Xiang
  0 siblings, 1 reply; 159+ messages in thread
From: Christoph Hellwig @ 2019-08-30 16:39 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Alexander Viro, Greg Kroah-Hartman,
	Andrew Morton, Stephen Rothwell, Theodore Ts'o, Pavel Machek,
	David Sterba, Amir Goldstein, Darrick J . Wong, Dave Chinner,
	Jaegeuk Kim, Jan Kara, Linus Torvalds, linux-fsdevel, devel,
	LKML, linux-erofs, Chao Yu, Miao Xie, Li Guifu, Fang Wei

On Thu, Aug 29, 2019 at 06:50:48PM +0800, Gao Xiang wrote:
> > Please use an erofs_ prefix for all your functions.
> 
> It is already a static function, I have no idea what is wrong here.

Which part of all wasn't clear?  Have you looked at the prefixes for
most functions in the various other big filesystems?

> > > +	/* be careful RCU symlink path (see ext4_inode_info->i_data)! */
> > > +	if (is_inode_fast_symlink(inode))
> > > +		kfree(inode->i_link);
> > 
> > is_inode_fast_symlink only shows up in a later patch.  And really
> > obsfucates the check here in the only caller as you can just do an
> > unconditional kfree here - i_link will be NULL except for the case
> > where you explicitly set it.
> 
> I cannot fully understand your point (sorry about my English),
> I will reply you about this later.

With that I mean that you should:

 1) remove is_inode_fast_symlink and just opencode it in the few places
    using it
 2) remove the check in this place entirely as it is not needed
 3) remove the comment quoted above as it is more confusing than not
    having the comment

> > Is there any good reasons to use buffer heads like this in new code
> > vs directly using bios?
> 
> This page can save in bdev page cache, it contains not only the erofs
> superblock so it can be fetched in page cache later.

If you want it in the page cache why not use read_mapping_page or similar?

> > > +/* set up default EROFS parameters */
> > > +static void default_options(struct erofs_sb_info *sbi)
> > > +{
> > > +}
> > 
> > No need to add an empty function.
> 
> Later patch will fill this function.

Please only add the function in the patch actually adding the
functionality.

> > > +}
> > 
> > Why is this needed?  You can just free your sb privatte information in
> > ->put_super and wire up kill_block_super as the ->kill_sb method
> > directly.
> 
> See Al's comments,
> https://lore.kernel.org/r/20190720224955.GD17978@ZenIV.linux.org.uk/

With that code it makes sense.  In this paticular patch it does not.
So please add it only when actually needed.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 04/24] erofs: add raw address_space operations
  2019-08-29 11:46     ` Gao Xiang
@ 2019-08-30 16:40       ` Christoph Hellwig
  2019-08-30 17:23         ` Gao Xiang
  0 siblings, 1 reply; 159+ messages in thread
From: Christoph Hellwig @ 2019-08-30 16:40 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Alexander Viro, Greg Kroah-Hartman,
	Andrew Morton, Stephen Rothwell, Theodore Ts'o, Pavel Machek,
	David Sterba, Amir Goldstein, Darrick J . Wong, Dave Chinner,
	Jaegeuk Kim, Jan Kara, Linus Torvalds, linux-fsdevel, devel,
	LKML, linux-erofs, Chao Yu, Miao Xie, Li Guifu, Fang Wei

On Thu, Aug 29, 2019 at 07:46:11PM +0800, Gao Xiang wrote:
> Hi Christoph,
> 
> On Thu, Aug 29, 2019 at 03:17:21AM -0700, Christoph Hellwig wrote:
> > The actual address_space operations seem to largely duplicate
> > the iomap versions.  Please use those instead.  Also I don't think
> > any new file system should write up ->bmap these days.
> 
> iomap doesn't support tail-end packing inline data till now,
> I think Chao and I told you and Andreas before [1].
> 
> Since EROFS keeps a self-contained driver for now, we will use
> iomap if it supports tail-end packing inline data later.

Well, so work with the maintainers to enhance the core kernel.  That
is how Linux development works.  We've added various iomap enhancements
for gfs in the last merge windows, and we've added more for the brand
new zonefs file system we plan to merge for 5.4.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 05/24] erofs: add inode operations
  2019-08-29 11:59     ` Gao Xiang
@ 2019-08-30 16:42       ` Christoph Hellwig
  2019-08-30 18:46         ` Gao Xiang
  0 siblings, 1 reply; 159+ messages in thread
From: Christoph Hellwig @ 2019-08-30 16:42 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Alexander Viro, Greg Kroah-Hartman,
	Andrew Morton, Stephen Rothwell, Theodore Ts'o, Pavel Machek,
	David Sterba, Amir Goldstein, Darrick J . Wong, Dave Chinner,
	Jaegeuk Kim, Jan Kara, Linus Torvalds, linux-fsdevel, devel,
	LKML, linux-erofs, Chao Yu, Miao Xie, Li Guifu, Fang Wei

On Thu, Aug 29, 2019 at 07:59:22PM +0800, Gao Xiang wrote:
> On Thu, Aug 29, 2019 at 03:24:26AM -0700, Christoph Hellwig wrote:
> 
> []
> 
> > 
> > > +
> > > +		/* fill last page if inline data is available */
> > > +		err = fill_inline_data(inode, data, ofs);
> > 
> > Well, I think you should move the is_inode_flat_inline and
> > (S_ISLNK(inode->i_mode) && inode->i_size < PAGE_SIZE) checks from that
> > helper here, as otherwise you make everyone wonder why you'd always
> > fill out the inline data.
> 
> Currently, fill_inline_data() only fills for fast symlink,
> later we can fill any tail-end block (such as dir block)
> for our requirements.

So change it when that later changes actually come in.  And even then
having the checks outside the function is a lot more obvious.

> And I think that is minor.

The problem is that each of these issues might appear minor on their
own.  But combined a lot of the coding style choices lead to code that
is more suitable an obsfucated code contest than the Linux kernel as
trying to understand even just a few places requires jumping through
tons of helpers with misleading names and spread over various files.

> The consideration is simply because iget_locked performs better
> than iget5_locked.

In what benchmark do the differences show up?

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 03/24] erofs: add super block operations
  2019-08-30 16:39       ` Christoph Hellwig
@ 2019-08-30 17:15         ` Gao Xiang
  2019-08-31  0:54           ` Gao Xiang
  2019-08-31  6:34           ` Amir Goldstein
  0 siblings, 2 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-30 17:15 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Darrick J . Wong, Dave Chinner, Jaegeuk Kim,
	Jan Kara, Linus Torvalds, linux-fsdevel, devel, LKML,
	linux-erofs, Chao Yu, Miao Xie, Li Guifu, Fang Wei

Hi Christoph,

On Fri, Aug 30, 2019 at 09:39:10AM -0700, Christoph Hellwig wrote:
> On Thu, Aug 29, 2019 at 06:50:48PM +0800, Gao Xiang wrote:
> > > Please use an erofs_ prefix for all your functions.
> > 
> > It is already a static function, I have no idea what is wrong here.
> 
> Which part of all wasn't clear?  Have you looked at the prefixes for
> most functions in the various other big filesystems?

I will add erofs prefix to free_inode as you said.

At least, all non-prefix functions in erofs are all static functions,
it won't pollute namespace... I will add "erofs_" to other meaningful
callbacks...And as you can see...

cifs/cifsfs.c
1303:cifs_init_inodecache(void)
1509:   rc = cifs_init_inodecache();

hpfs/super.c
254:static int init_inodecache(void)
771:    int err = init_inodecache();

minix/inode.c
84:static int __init init_inodecache(void)
665:    int err = init_inodecache();

isofs/inode.c
88:static int __init init_inodecache(void)
1580:   int err = init_inodecache();

bfs/inode.c
261:static int __init init_inodecache(void)
468:    int err = init_inodecache();

ext4/super.c
1144:static int __init init_inodecache(void)
6115:   err = init_inodecache();

reiserfs/super.c
666:static int __init init_inodecache(void)
2606:   ret = init_inodecache();

squashfs/super.c
406:static int __init init_inodecache(void)
430:    int err = init_inodecache();

udf/super.c
177:static int __init init_inodecache(void)
232:    err = init_inodecache();

qnx4/inode.c
358:static int init_inodecache(void)
399:    err = init_inodecache();

ufs/super.c
1463:static int __init init_inodecache(void)
1517:   int err = init_inodecache();

qnx6/inode.c
618:static int init_inodecache(void)
659:    err = init_inodecache();

f2fs/super.c
3540:static int __init init_inodecache(void)
3572:   err = init_inodecache();


> 
> > > > +	/* be careful RCU symlink path (see ext4_inode_info->i_data)! */
> > > > +	if (is_inode_fast_symlink(inode))
> > > > +		kfree(inode->i_link);
> > > 
> > > is_inode_fast_symlink only shows up in a later patch.  And really
> > > obsfucates the check here in the only caller as you can just do an
> > > unconditional kfree here - i_link will be NULL except for the case
> > > where you explicitly set it.
> > 
> > I cannot fully understand your point (sorry about my English),
> > I will reply you about this later.
> 
> With that I mean that you should:
> 
>  1) remove is_inode_fast_symlink and just opencode it in the few places
>     using it
>  2) remove the check in this place entirely as it is not needed
>  3) remove the comment quoted above as it is more confusing than not
>     having the comment

Got it, thanks!

> 
> > > Is there any good reasons to use buffer heads like this in new code
> > > vs directly using bios?
> > 
> > This page can save in bdev page cache, it contains not only the erofs
> > superblock so it can be fetched in page cache later.
> 
> If you want it in the page cache why not use read_mapping_page or similar?

It's reasonable, I will change as you suggested.
(The difference is whether it has some buffer_head to the sb page or not...)

> 
> > > > +/* set up default EROFS parameters */
> > > > +static void default_options(struct erofs_sb_info *sbi)
> > > > +{
> > > > +}
> > > 
> > > No need to add an empty function.
> > 
> > Later patch will fill this function.
> 
> Please only add the function in the patch actually adding the
> functionality.

That was my fault when spilting patches...considering
it's an >7KLOC filesystem (maybe spilting the whole xfs or
ext4 properly is more harder)... Anyway, that is my fault.

> 
> > > > +}
> > > 
> > > Why is this needed?  You can just free your sb privatte information in
> > > ->put_super and wire up kill_block_super as the ->kill_sb method
> > > directly.
> > 
> > See Al's comments,
> > https://lore.kernel.org/r/20190720224955.GD17978@ZenIV.linux.org.uk/
> 
> With that code it makes sense.  In this paticular patch it does not.
> So please add it only when actually needed.

Same as above...

Thanks,
Gao Xiang


^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 04/24] erofs: add raw address_space operations
  2019-08-30 16:40       ` Christoph Hellwig
@ 2019-08-30 17:23         ` Gao Xiang
  0 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-30 17:23 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Darrick J . Wong, Dave Chinner, Jaegeuk Kim,
	Jan Kara, Linus Torvalds, linux-fsdevel, devel, LKML,
	linux-erofs, Chao Yu, Miao Xie, Li Guifu, Fang Wei

Hi Christoph,

On Fri, Aug 30, 2019 at 09:40:13AM -0700, Christoph Hellwig wrote:
> On Thu, Aug 29, 2019 at 07:46:11PM +0800, Gao Xiang wrote:
> > Hi Christoph,
> > 
> > On Thu, Aug 29, 2019 at 03:17:21AM -0700, Christoph Hellwig wrote:
> > > The actual address_space operations seem to largely duplicate
> > > the iomap versions.  Please use those instead.  Also I don't think
> > > any new file system should write up ->bmap these days.
> > 
> > iomap doesn't support tail-end packing inline data till now,
> > I think Chao and I told you and Andreas before [1].
> > 
> > Since EROFS keeps a self-contained driver for now, we will use
> > iomap if it supports tail-end packing inline data later.
> 
> Well, so work with the maintainers to enhance the core kernel.  That
> is how Linux development works.  We've added various iomap enhancements
> for gfs in the last merge windows, and we've added more for the brand
> new zonefs file system we plan to merge for 5.4.

That is a good idea, I think Chao will continue working on this
(adding tail-end packing inline approach into iomap, thus we can
 have few code in data.c.)

Thanks,
Gao Xiang


^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 05/24] erofs: add inode operations
  2019-08-30 16:42       ` Christoph Hellwig
@ 2019-08-30 18:46         ` Gao Xiang
  0 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-30 18:46 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Darrick J . Wong, Dave Chinner, Jaegeuk Kim,
	Jan Kara, Linus Torvalds, linux-fsdevel, devel, LKML,
	linux-erofs, Chao Yu, Miao Xie, Li Guifu, Fang Wei

Hi Christoph,

On Fri, Aug 30, 2019 at 09:42:05AM -0700, Christoph Hellwig wrote:
> On Thu, Aug 29, 2019 at 07:59:22PM +0800, Gao Xiang wrote:
> > On Thu, Aug 29, 2019 at 03:24:26AM -0700, Christoph Hellwig wrote:
> > 
> > []
> > 
> > > 
> > > > +
> > > > +		/* fill last page if inline data is available */
> > > > +		err = fill_inline_data(inode, data, ofs);
> > > 
> > > Well, I think you should move the is_inode_flat_inline and
> > > (S_ISLNK(inode->i_mode) && inode->i_size < PAGE_SIZE) checks from that
> > > helper here, as otherwise you make everyone wonder why you'd always
> > > fill out the inline data.
> > 
> > Currently, fill_inline_data() only fills for fast symlink,
> > later we can fill any tail-end block (such as dir block)
> > for our requirements.
> 
> So change it when that later changes actually come in.  And even then
> having the checks outside the function is a lot more obvious.

Okay.

> 
> > And I think that is minor.
> 
> The problem is that each of these issues might appear minor on their
> own.  But combined a lot of the coding style choices lead to code that
> is more suitable an obsfucated code contest than the Linux kernel as
> trying to understand even just a few places requires jumping through
> tons of helpers with misleading names and spread over various files.
> 
> > The consideration is simply because iget_locked performs better
> > than iget5_locked.
> 
> In what benchmark do the differences show up?

In a word, no benchmark here, just because
"unsigned long on 32-bit platforms is 4 bytes."
but erofs nid is a 64-bit number.

iget_locked will do find_inode_fast (no callback at all)
rather than iget5_locked --> find_inode (test callback) ->
            inode_insert5(set callback) for each new inode.

For most 64-bit platforms, iget_locked is enough,
32-bit platforms become rare...

Thanks,
Gao Xiang


^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 03/24] erofs: add super block operations
  2019-08-30 17:15         ` Gao Xiang
@ 2019-08-31  0:54           ` Gao Xiang
  2019-08-31  6:34           ` Amir Goldstein
  1 sibling, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-31  0:54 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Darrick J . Wong, Dave Chinner, Jaegeuk Kim,
	Jan Kara, Linus Torvalds, linux-fsdevel, devel, LKML,
	linux-erofs, Chao Yu, Miao Xie, Li Guifu, Fang Wei

Hi Christoph,

On Sat, Aug 31, 2019 at 01:15:10AM +0800, Gao Xiang wrote:

[]

> > 
> > > > > +	/* be careful RCU symlink path (see ext4_inode_info->i_data)! */
> > > > > +	if (is_inode_fast_symlink(inode))
> > > > > +		kfree(inode->i_link);
> > > > 
> > > > is_inode_fast_symlink only shows up in a later patch.  And really
> > > > obsfucates the check here in the only caller as you can just do an
> > > > unconditional kfree here - i_link will be NULL except for the case
> > > > where you explicitly set it.
> > > 
> > > I cannot fully understand your point (sorry about my English),
> > > I will reply you about this later.
> > 
> > With that I mean that you should:
> > 
> >  1) remove is_inode_fast_symlink and just opencode it in the few places
> >     using it
> >  2) remove the check in this place entirely as it is not needed

Add some words about this suggestion since I'm addressing this place, it
seems it could not (or I am not sure at least) be freed unconditionally

	union {
		struct pipe_inode_info	*i_pipe;
		struct block_device	*i_bdev;
		struct cdev		*i_cdev;
		char			*i_link;
		unsigned		i_dir_seq;
	};

while I saw what shmem did, it seems that they handle as follows:
3636 static void shmem_free_in_core_inode(struct inode *inode)
3637 {
3638         if (S_ISLNK(inode->i_mode))
3639                 kfree(inode->i_link);
3640         kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode));
3641 }

I think that would be some check on it to get it is a symlink (for
i_dir_seq it seems unsafe).... I think the original check is ok but
I will opencode it instead.

Thanks,
Gao Xiang


^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 03/24] erofs: add super block operations
  2019-08-30 17:15         ` Gao Xiang
  2019-08-31  0:54           ` Gao Xiang
@ 2019-08-31  6:34           ` Amir Goldstein
  2019-08-31  6:48             ` Gao Xiang
  1 sibling, 1 reply; 159+ messages in thread
From: Amir Goldstein @ 2019-08-31  6:34 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Alexander Viro, Greg Kroah-Hartman,
	Andrew Morton, Stephen Rothwell, Theodore Ts'o, Pavel Machek,
	David Sterba, Darrick J . Wong, Dave Chinner, Jaegeuk Kim,
	Jan Kara, Linus Torvalds, linux-fsdevel, devel, LKML,
	linux-erofs, Chao Yu, Miao Xie, Li Guifu, Fang Wei

On Fri, Aug 30, 2019 at 8:16 PM Gao Xiang <gaoxiang25@huawei.com> wrote:
>
> Hi Christoph,
>
> On Fri, Aug 30, 2019 at 09:39:10AM -0700, Christoph Hellwig wrote:
> > On Thu, Aug 29, 2019 at 06:50:48PM +0800, Gao Xiang wrote:
> > > > Please use an erofs_ prefix for all your functions.
> > >
> > > It is already a static function, I have no idea what is wrong here.
> >
> > Which part of all wasn't clear?  Have you looked at the prefixes for
> > most functions in the various other big filesystems?
>
> I will add erofs prefix to free_inode as you said.
>
> At least, all non-prefix functions in erofs are all static functions,
> it won't pollute namespace... I will add "erofs_" to other meaningful
> callbacks...And as you can see...
>
> cifs/cifsfs.c
> 1303:cifs_init_inodecache(void)
> 1509:   rc = cifs_init_inodecache();
>
> hpfs/super.c
> 254:static int init_inodecache(void)
> 771:    int err = init_inodecache();
>
> minix/inode.c
> 84:static int __init init_inodecache(void)
> 665:    int err = init_inodecache();
>

Hi Gao,

"They did it first" is never a good reply for code review comments.
Nobody cares if you copy&paste code with init_inodecache().
I understand why you thought static function names do not pollute
the (linker) namespace, but they do pollute the global namespace.

free_inode() as a local function name is one of the worst examples
for VFS namespace pollution.

VFS code uses function names like those a lot in the global namespace, e.g.:
clear_inode(),new_inode().

For example from recent history of namespace collision caused by your line
of thinking, see:
e6fd2093a85d md: namespace private helper names

Besides, you really have nothing to loose from prefixing everything
with erofs_, do you? It's better for review, for debugging...

Thanks,
Amir.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 03/24] erofs: add super block operations
  2019-08-31  6:34           ` Amir Goldstein
@ 2019-08-31  6:48             ` Gao Xiang
  0 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-08-31  6:48 UTC (permalink / raw)
  To: Amir Goldstein
  Cc: Christoph Hellwig, Alexander Viro, Greg Kroah-Hartman,
	Andrew Morton, Stephen Rothwell, Theodore Ts'o, Pavel Machek,
	David Sterba, Darrick J . Wong, Dave Chinner, Jaegeuk Kim,
	Jan Kara, Linus Torvalds, linux-fsdevel, devel, LKML,
	linux-erofs, Chao Yu, Miao Xie, Li Guifu, Fang Wei

On Sat, Aug 31, 2019 at 09:34:44AM +0300, Amir Goldstein wrote:
> On Fri, Aug 30, 2019 at 8:16 PM Gao Xiang <gaoxiang25@huawei.com> wrote:
> >
> > Hi Christoph,
> >
> > On Fri, Aug 30, 2019 at 09:39:10AM -0700, Christoph Hellwig wrote:
> > > On Thu, Aug 29, 2019 at 06:50:48PM +0800, Gao Xiang wrote:
> > > > > Please use an erofs_ prefix for all your functions.
> > > >
> > > > It is already a static function, I have no idea what is wrong here.
> > >
> > > Which part of all wasn't clear?  Have you looked at the prefixes for
> > > most functions in the various other big filesystems?
> >
> > I will add erofs prefix to free_inode as you said.
> >
> > At least, all non-prefix functions in erofs are all static functions,
> > it won't pollute namespace... I will add "erofs_" to other meaningful
> > callbacks...And as you can see...
> >
> > cifs/cifsfs.c
> > 1303:cifs_init_inodecache(void)
> > 1509:   rc = cifs_init_inodecache();
> >
> > hpfs/super.c
> > 254:static int init_inodecache(void)
> > 771:    int err = init_inodecache();
> >
> > minix/inode.c
> > 84:static int __init init_inodecache(void)
> > 665:    int err = init_inodecache();
> >
> 
> Hi Gao,
> 
> "They did it first" is never a good reply for code review comments.
> Nobody cares if you copy&paste code with init_inodecache().
> I understand why you thought static function names do not pollute
> the (linker) namespace, but they do pollute the global namespace.
> 
> free_inode() as a local function name is one of the worst examples
> for VFS namespace pollution.
> 
> VFS code uses function names like those a lot in the global namespace, e.g.:
> clear_inode(),new_inode().
> 
> For example from recent history of namespace collision caused by your line
> of thinking, see:
> e6fd2093a85d md: namespace private helper names
> 
> Besides, you really have nothing to loose from prefixing everything
> with erofs_, do you? It's better for review, for debugging...

Hi Amir,

Thanks for you kind reply...

Yes, I understand that some generic header files
could have the same function names and cause bad
behaviors...

I will fix them, my only one question is "if all
function/variable names are prefixed with "erofs_"
(including all inline helpers in header files),
it seems somewhat strange... (too many statements
start "erofs_" in the source code...)"

I will fix common and short names at once...

Thanks,
Gao Xiang

> 
> Thanks,
> Amir.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH 00/21] erofs: patchset addressing Christoph's comments
  2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
                   ` (23 preceding siblings ...)
  2019-08-02 12:53 ` [PATCH v6 24/24] erofs: add document Gao Xiang
@ 2019-09-01  5:51 ` Gao Xiang
  2019-09-01  5:51   ` [PATCH 01/21] erofs: remove all the byte offset comments Gao Xiang
                     ` (22 more replies)
  24 siblings, 23 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-01  5:51 UTC (permalink / raw)
  To: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman
  Cc: linux-fsdevel, devel, linux-erofs, Chao Yu, Gao Xiang

Hi,

This patchset is based on the following patch by Pratik Shinde,
https://lore.kernel.org/linux-erofs/20190830095615.10995-1-pratikshinde320@gmail.com/

All patches addressing Christoph's comments on v6, which are trivial,
most deleted code are from erofs specific fault injection, which was
followed f2fs and previously discussed in earlier topic [1], but
let's follow what Christoph's said now.

Comments and suggestions are welcome...

[1] https://lore.kernel.org/r/1eed1e6b-f95e-aa8e-c3e7-e9870401ee23@kernel.org/

Thanks,
Gao Xiang

Gao Xiang (21):
  erofs: remove all the byte offset comments
  erofs: on-disk format should have explicitly assigned numbers
  erofs: some macros are much more readable as a function
  erofs: kill __packed for on-disk structures
  erofs: update erofs_inode_is_data_compressed helper
  erofs: kill erofs_{init,exit}_inode_cache
  erofs: use erofs_inode naming
  erofs: update comments in inode.c
  erofs: update erofs symlink stuffs
  erofs: kill is_inode_layout_compression()
  erofs: use dsb instead of layout for ondisk super_block
  erofs: kill verbose debug info in erofs_fill_super
  erofs: simplify erofs_grab_bio() since bio_alloc() never fail
  erofs: kill prio and nofail of erofs_get_meta_page()
  erofs: kill __submit_bio()
  erofs: kill magic underscores
  erofs: use a switch statement when dealing with the file modes
  erofs: add "erofs_" prefix for common and short functions
  erofs: kill all erofs specific fault injection
  erofs: kill use_vmap module parameter
  erofs: save one level of indentation

 Documentation/filesystems/erofs.txt |   9 --
 fs/erofs/Kconfig                    |   7 --
 fs/erofs/data.c                     |  62 +++-------
 fs/erofs/decompressor.c             |  34 ++---
 fs/erofs/dir.c                      |   6 +-
 fs/erofs/erofs_fs.h                 | 162 ++++++++++++------------
 fs/erofs/inode.c                    | 176 +++++++++++++-------------
 fs/erofs/internal.h                 | 156 +++--------------------
 fs/erofs/namei.c                    |  12 +-
 fs/erofs/super.c                    | 185 ++++++++--------------------
 fs/erofs/xattr.c                    |  33 +++--
 fs/erofs/xattr.h                    |   4 +-
 fs/erofs/zdata.c                    |  44 +++----
 fs/erofs/zmap.c                     |  32 ++---
 include/trace/events/erofs.h        |  14 +--
 15 files changed, 338 insertions(+), 598 deletions(-)

-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH 01/21] erofs: remove all the byte offset comments
  2019-09-01  5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang
@ 2019-09-01  5:51   ` Gao Xiang
  2019-09-02 12:05     ` Christoph Hellwig
  2019-09-01  5:51   ` [PATCH 02/21] erofs: on-disk format should have explicitly assigned numbers Gao Xiang
                     ` (21 subsequent siblings)
  22 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-01  5:51 UTC (permalink / raw)
  To: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman
  Cc: linux-fsdevel, devel, linux-erofs, Chao Yu, Gao Xiang

From: Gao Xiang <gaoxiang25@huawei.com>

As Christoph suggested [1], "Please remove all the byte offset comments.
that is something that can easily be checked with gdb or pahole."

[1] https://lore.kernel.org/r/20190829095954.GB20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/erofs_fs.h | 105 +++++++++++++++++++++++---------------------
 1 file changed, 54 insertions(+), 51 deletions(-)

diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
index afa7d45ca958..49335fff9d65 100644
--- a/fs/erofs/erofs_fs.h
+++ b/fs/erofs/erofs_fs.h
@@ -17,27 +17,28 @@
 #define EROFS_REQUIREMENT_LZ4_0PADDING	0x00000001
 #define EROFS_ALL_REQUIREMENTS		EROFS_REQUIREMENT_LZ4_0PADDING
 
+/* 128-byte erofs on-disk super block */
 struct erofs_super_block {
-/*  0 */__le32 magic;           /* in the little endian */
-/*  4 */__le32 checksum;        /* crc32c(super_block) */
-/*  8 */__le32 features;        /* (aka. feature_compat) */
-/* 12 */__u8 blkszbits;         /* support block_size == PAGE_SIZE only */
-/* 13 */__u8 reserved;
-
-/* 14 */__le16 root_nid;
-/* 16 */__le64 inos;            /* total valid ino # (== f_files - f_favail) */
-
-/* 24 */__le64 build_time;      /* inode v1 time derivation */
-/* 32 */__le32 build_time_nsec;
-/* 36 */__le32 blocks;          /* used for statfs */
-/* 40 */__le32 meta_blkaddr;
-/* 44 */__le32 xattr_blkaddr;
-/* 48 */__u8 uuid[16];          /* 128-bit uuid for volume */
-/* 64 */__u8 volume_name[16];   /* volume name */
-/* 80 */__le32 requirements;    /* (aka. feature_incompat) */
-
-/* 84 */__u8 reserved2[44];
-} __packed;                     /* 128 bytes */
+	__le32 magic;           /* file system magic number */
+	__le32 checksum;        /* crc32c(super_block) */
+	__le32 features;        /* (aka. feature_compat) */
+	__u8 blkszbits;         /* support block_size == PAGE_SIZE only */
+	__u8 reserved;
+
+	__le16 root_nid;	/* nid of root directory */
+	__le64 inos;            /* total valid ino # (== f_files - f_favail) */
+
+	__le64 build_time;      /* inode v1 time derivation */
+	__le32 build_time_nsec;	/* inode v1 time derivation in nano scale */
+	__le32 blocks;          /* used for statfs */
+	__le32 meta_blkaddr;	/* start block address of metadata area */
+	__le32 xattr_blkaddr;	/* start block address of shared xattr area */
+	__u8 uuid[16];          /* 128-bit uuid for volume */
+	__u8 volume_name[16];   /* volume name */
+	__le32 requirements;    /* (aka. feature_incompat) */
+
+	__u8 reserved2[44];
+} __packed;
 
 /*
  * erofs inode data mapping:
@@ -73,16 +74,17 @@ static inline bool erofs_inode_is_data_compressed(unsigned int datamode)
 #define EROFS_I_VERSION_BIT             0
 #define EROFS_I_DATA_MAPPING_BIT        1
 
+/* 32-byte reduced form of an ondisk inode */
 struct erofs_inode_v1 {
-/*  0 */__le16 i_advise;
+	__le16 i_advise;	/* inode hints */
 
 /* 1 header + n-1 * 4 bytes inline xattr to keep continuity */
-/*  2 */__le16 i_xattr_icount;
-/*  4 */__le16 i_mode;
-/*  6 */__le16 i_nlink;
-/*  8 */__le32 i_size;
-/* 12 */__le32 i_reserved;
-/* 16 */union {
+	__le16 i_xattr_icount;
+	__le16 i_mode;
+	__le16 i_nlink;
+	__le32 i_size;
+	__le32 i_reserved;
+	union {
 		/* file total compressed blocks for data mapping 1 */
 		__le32 compressed_blocks;
 		__le32 raw_blkaddr;
@@ -90,10 +92,10 @@ struct erofs_inode_v1 {
 		/* for device files, used to indicate old/new device # */
 		__le32 rdev;
 	} i_u __packed;
-/* 20 */__le32 i_ino;           /* only used for 32-bit stat compatibility */
-/* 24 */__le16 i_uid;
-/* 26 */__le16 i_gid;
-/* 28 */__le32 i_reserved2;
+	__le32 i_ino;           /* only used for 32-bit stat compatibility */
+	__le16 i_uid;
+	__le16 i_gid;
+	__le32 i_reserved2;
 } __packed;
 
 /* 32 bytes on-disk inode */
@@ -101,15 +103,16 @@ struct erofs_inode_v1 {
 /* 64 bytes on-disk inode */
 #define EROFS_INODE_LAYOUT_V2   1
 
+/* 64-byte complete form of an ondisk inode */
 struct erofs_inode_v2 {
-/*  0 */__le16 i_advise;
+	__le16 i_advise;	/* inode hints */
 
 /* 1 header + n-1 * 4 bytes inline xattr to keep continuity */
-/*  2 */__le16 i_xattr_icount;
-/*  4 */__le16 i_mode;
-/*  6 */__le16 i_reserved;
-/*  8 */__le64 i_size;
-/* 16 */union {
+	__le16 i_xattr_icount;
+	__le16 i_mode;
+	__le16 i_reserved;
+	__le64 i_size;
+	union {
 		/* file total compressed blocks for data mapping 1 */
 		__le32 compressed_blocks;
 		__le32 raw_blkaddr;
@@ -119,15 +122,15 @@ struct erofs_inode_v2 {
 	} i_u __packed;
 
 	/* only used for 32-bit stat compatibility */
-/* 20 */__le32 i_ino;
-
-/* 24 */__le32 i_uid;
-/* 28 */__le32 i_gid;
-/* 32 */__le64 i_ctime;
-/* 40 */__le32 i_ctime_nsec;
-/* 44 */__le32 i_nlink;
-/* 48 */__u8   i_reserved2[16];
-} __packed;                     /* 64 bytes */
+	__le32 i_ino;
+
+	__le32 i_uid;
+	__le32 i_gid;
+	__le64 i_ctime;
+	__le32 i_ctime_nsec;
+	__le32 i_nlink;
+	__u8   i_reserved2[16];
+} __packed;
 
 #define EROFS_MAX_SHARED_XATTRS         (128)
 /* h_shared_count between 129 ... 255 are special # */
@@ -264,7 +267,7 @@ struct z_erofs_vle_decompressed_index {
 		 * [1] - pointing to the tail cluster
 		 */
 		__le16 delta[2];
-	} di_u __packed;		/* 8 bytes */
+	} di_u __packed;
 } __packed;
 
 #define Z_EROFS_VLE_LEGACY_INDEX_ALIGN(size) \
@@ -273,10 +276,10 @@ struct z_erofs_vle_decompressed_index {
 
 /* dirent sorts in alphabet order, thus we can do binary search */
 struct erofs_dirent {
-	__le64 nid;     /*  0, node number */
-	__le16 nameoff; /*  8, start offset of file name */
-	__u8 file_type; /* 10, file type */
-	__u8 reserved;  /* 11, reserved */
+	__le64 nid;     /* node number */
+	__le16 nameoff; /* start offset of file name */
+	__u8 file_type; /* file type */
+	__u8 reserved;  /* reserved */
 } __packed;
 
 /*
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH 02/21] erofs: on-disk format should have explicitly assigned numbers
  2019-09-01  5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang
  2019-09-01  5:51   ` [PATCH 01/21] erofs: remove all the byte offset comments Gao Xiang
@ 2019-09-01  5:51   ` Gao Xiang
  2019-09-02 12:05     ` Christoph Hellwig
  2019-09-01  5:51   ` [PATCH 03/21] erofs: some macros are much more readable as a function Gao Xiang
                     ` (20 subsequent siblings)
  22 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-01  5:51 UTC (permalink / raw)
  To: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman
  Cc: linux-fsdevel, devel, linux-erofs, Chao Yu, Gao Xiang

From: Gao Xiang <gaoxiang25@huawei.com>

As Christoph claimed [1], on-disk format should have
explicitly assigned numbers. I have to change it.

[1] https://lore.kernel.org/r/20190829095954.GB20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/erofs_fs.h | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
index 49335fff9d65..d1f152a3670a 100644
--- a/fs/erofs/erofs_fs.h
+++ b/fs/erofs/erofs_fs.h
@@ -53,10 +53,10 @@ struct erofs_super_block {
  * 4~7 - reserved
  */
 enum {
-	EROFS_INODE_FLAT_PLAIN,
-	EROFS_INODE_FLAT_COMPRESSION_LEGACY,
-	EROFS_INODE_FLAT_INLINE,
-	EROFS_INODE_FLAT_COMPRESSION,
+	EROFS_INODE_FLAT_PLAIN			= 0,
+	EROFS_INODE_FLAT_COMPRESSION_LEGACY	= 1,
+	EROFS_INODE_FLAT_INLINE			= 2,
+	EROFS_INODE_FLAT_COMPRESSION		= 3,
 	EROFS_INODE_LAYOUT_MAX
 };
 
@@ -184,7 +184,7 @@ struct erofs_xattr_entry {
 
 /* available compression algorithm types */
 enum {
-	Z_EROFS_COMPRESSION_LZ4,
+	Z_EROFS_COMPRESSION_LZ4	= 0,
 	Z_EROFS_COMPRESSION_MAX
 };
 
@@ -242,10 +242,10 @@ struct z_erofs_map_header {
  *                (di_advise could be 0, 1 or 2)
  */
 enum {
-	Z_EROFS_VLE_CLUSTER_TYPE_PLAIN,
-	Z_EROFS_VLE_CLUSTER_TYPE_HEAD,
-	Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD,
-	Z_EROFS_VLE_CLUSTER_TYPE_RESERVED,
+	Z_EROFS_VLE_CLUSTER_TYPE_PLAIN		= 0,
+	Z_EROFS_VLE_CLUSTER_TYPE_HEAD		= 1,
+	Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD	= 2,
+	Z_EROFS_VLE_CLUSTER_TYPE_RESERVED	= 3,
 	Z_EROFS_VLE_CLUSTER_TYPE_MAX
 };
 
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH 03/21] erofs: some macros are much more readable as a function
  2019-09-01  5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang
  2019-09-01  5:51   ` [PATCH 01/21] erofs: remove all the byte offset comments Gao Xiang
  2019-09-01  5:51   ` [PATCH 02/21] erofs: on-disk format should have explicitly assigned numbers Gao Xiang
@ 2019-09-01  5:51   ` Gao Xiang
  2019-09-02 12:06     ` Christoph Hellwig
  2019-09-01  5:51   ` [PATCH 04/21] erofs: kill __packed for on-disk structures Gao Xiang
                     ` (19 subsequent siblings)
  22 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-01  5:51 UTC (permalink / raw)
  To: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman
  Cc: linux-fsdevel, devel, linux-erofs, Chao Yu, Gao Xiang

From: Gao Xiang <gaoxiang25@huawei.com>

As Christoph suggested [1], these macros are much
more readable as a function.

[1] https://lore.kernel.org/r/20190829095954.GB20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/erofs_fs.h | 22 ++++++++++++++--------
 fs/erofs/inode.c    |  4 ++--
 fs/erofs/xattr.c    |  2 +-
 3 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
index d1f152a3670a..c1220b0f26e0 100644
--- a/fs/erofs/erofs_fs.h
+++ b/fs/erofs/erofs_fs.h
@@ -171,16 +171,22 @@ struct erofs_xattr_entry {
 	char   e_name[0];       /* attribute name */
 } __packed;
 
-#define ondisk_xattr_ibody_size(count)	({\
-	u32 __count = le16_to_cpu(count); \
-	((__count) == 0) ? 0 : \
-	sizeof(struct erofs_xattr_ibody_header) + \
-		sizeof(__u32) * ((__count) - 1); })
+static inline unsigned int erofs_xattr_ibody_size(__le16 i_xattr_icount)
+{
+	if (!i_xattr_icount)
+		return 0;
+
+	return sizeof(struct erofs_xattr_ibody_header) +
+		sizeof(__u32) * (le16_to_cpu(i_xattr_icount) - 1);
+}
 
 #define EROFS_XATTR_ALIGN(size) round_up(size, sizeof(struct erofs_xattr_entry))
-#define EROFS_XATTR_ENTRY_SIZE(entry) EROFS_XATTR_ALIGN( \
-	sizeof(struct erofs_xattr_entry) + \
-	(entry)->e_name_len + le16_to_cpu((entry)->e_value_size))
+
+static inline unsigned int erofs_xattr_entry_size(struct erofs_xattr_entry *e)
+{
+	return EROFS_XATTR_ALIGN(sizeof(struct erofs_xattr_entry) +
+				 e->e_name_len + le16_to_cpu(e->e_value_size));
+}
 
 /* available compression algorithm types */
 enum {
diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index 8a0574530a0a..3fc4f764b387 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -29,7 +29,7 @@ static int read_inode(struct inode *inode, void *data)
 		struct erofs_inode_v2 *v2 = data;
 
 		vi->inode_isize = sizeof(struct erofs_inode_v2);
-		vi->xattr_isize = ondisk_xattr_ibody_size(v2->i_xattr_icount);
+		vi->xattr_isize = erofs_xattr_ibody_size(v2->i_xattr_icount);
 
 		inode->i_mode = le16_to_cpu(v2->i_mode);
 		if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
@@ -62,7 +62,7 @@ static int read_inode(struct inode *inode, void *data)
 		struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
 
 		vi->inode_isize = sizeof(struct erofs_inode_v1);
-		vi->xattr_isize = ondisk_xattr_ibody_size(v1->i_xattr_icount);
+		vi->xattr_isize = erofs_xattr_ibody_size(v1->i_xattr_icount);
 
 		inode->i_mode = le16_to_cpu(v1->i_mode);
 		if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c
index d80f61dde72f..620cbc15f4d0 100644
--- a/fs/erofs/xattr.c
+++ b/fs/erofs/xattr.c
@@ -231,7 +231,7 @@ static int xattr_foreach(struct xattr_iter *it,
 	 */
 	entry = *(struct erofs_xattr_entry *)(it->kaddr + it->ofs);
 	if (tlimit) {
-		unsigned int entry_sz = EROFS_XATTR_ENTRY_SIZE(&entry);
+		unsigned int entry_sz = erofs_xattr_entry_size(&entry);
 
 		/* xattr on-disk corruption: xattr entry beyond xattr_isize */
 		if (*tlimit < entry_sz) {
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH 04/21] erofs: kill __packed for on-disk structures
  2019-09-01  5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang
                     ` (2 preceding siblings ...)
  2019-09-01  5:51   ` [PATCH 03/21] erofs: some macros are much more readable as a function Gao Xiang
@ 2019-09-01  5:51   ` Gao Xiang
  2019-09-02 12:06     ` Christoph Hellwig
  2019-09-01  5:51   ` [PATCH 05/21] erofs: update erofs_inode_is_data_compressed helper Gao Xiang
                     ` (18 subsequent siblings)
  22 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-01  5:51 UTC (permalink / raw)
  To: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman
  Cc: linux-fsdevel, devel, linux-erofs, Chao Yu, Gao Xiang

From: Gao Xiang <gaoxiang25@huawei.com>

As Christoph suggested "Please don't add __packed" [1],
remove all __packed except struct erofs_dirent here.

Note that all on-disk fields except struct erofs_dirent
(12 bytes with a 8-byte nid) in EROFS are naturally aligned.

[1] https://lore.kernel.org/r/20190829095954.GB20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/erofs_fs.h | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
index c1220b0f26e0..59dcc2e8cb02 100644
--- a/fs/erofs/erofs_fs.h
+++ b/fs/erofs/erofs_fs.h
@@ -38,7 +38,7 @@ struct erofs_super_block {
 	__le32 requirements;    /* (aka. feature_incompat) */
 
 	__u8 reserved2[44];
-} __packed;
+};
 
 /*
  * erofs inode data mapping:
@@ -91,12 +91,12 @@ struct erofs_inode_v1 {
 
 		/* for device files, used to indicate old/new device # */
 		__le32 rdev;
-	} i_u __packed;
+	} i_u;
 	__le32 i_ino;           /* only used for 32-bit stat compatibility */
 	__le16 i_uid;
 	__le16 i_gid;
 	__le32 i_reserved2;
-} __packed;
+};
 
 /* 32 bytes on-disk inode */
 #define EROFS_INODE_LAYOUT_V1   0
@@ -119,7 +119,7 @@ struct erofs_inode_v2 {
 
 		/* for device files, used to indicate old/new device # */
 		__le32 rdev;
-	} i_u __packed;
+	} i_u;
 
 	/* only used for 32-bit stat compatibility */
 	__le32 i_ino;
@@ -130,7 +130,7 @@ struct erofs_inode_v2 {
 	__le32 i_ctime_nsec;
 	__le32 i_nlink;
 	__u8   i_reserved2[16];
-} __packed;
+};
 
 #define EROFS_MAX_SHARED_XATTRS         (128)
 /* h_shared_count between 129 ... 255 are special # */
@@ -152,7 +152,7 @@ struct erofs_xattr_ibody_header {
 	__u8   h_shared_count;
 	__u8   h_reserved2[7];
 	__le32 h_shared_xattrs[0];      /* shared xattr id array */
-} __packed;
+};
 
 /* Name indexes */
 #define EROFS_XATTR_INDEX_USER              1
@@ -169,7 +169,7 @@ struct erofs_xattr_entry {
 	__le16 e_value_size;    /* size of attribute value */
 	/* followed by e_name and e_value */
 	char   e_name[0];       /* attribute name */
-} __packed;
+};
 
 static inline unsigned int erofs_xattr_ibody_size(__le16 i_xattr_icount)
 {
@@ -273,8 +273,8 @@ struct z_erofs_vle_decompressed_index {
 		 * [1] - pointing to the tail cluster
 		 */
 		__le16 delta[2];
-	} di_u __packed;
-} __packed;
+	} di_u;
+};
 
 #define Z_EROFS_VLE_LEGACY_INDEX_ALIGN(size) \
 	(round_up(size, sizeof(struct z_erofs_vle_decompressed_index)) + \
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH 05/21] erofs: update erofs_inode_is_data_compressed helper
  2019-09-01  5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang
                     ` (3 preceding siblings ...)
  2019-09-01  5:51   ` [PATCH 04/21] erofs: kill __packed for on-disk structures Gao Xiang
@ 2019-09-01  5:51   ` Gao Xiang
  2019-09-02 12:07     ` Christoph Hellwig
  2019-09-01  5:51   ` [PATCH 06/21] erofs: kill erofs_{init,exit}_inode_cache Gao Xiang
                     ` (17 subsequent siblings)
  22 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-01  5:51 UTC (permalink / raw)
  To: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman
  Cc: linux-fsdevel, devel, linux-erofs, Chao Yu, Gao Xiang

From: Gao Xiang <gaoxiang25@huawei.com>

As Christoph said, "This looks like a really obsfucated
way to write:
	return datamode == EROFS_INODE_FLAT_COMPRESSION ||
		datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY; "

Although I had my own consideration, it's the right way for now.

[1] https://lore.kernel.org/linux-fsdevel/20190829095954.GB20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/erofs_fs.h | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
index 59dcc2e8cb02..87d7ae82339a 100644
--- a/fs/erofs/erofs_fs.h
+++ b/fs/erofs/erofs_fs.h
@@ -62,9 +62,8 @@ enum {
 
 static inline bool erofs_inode_is_data_compressed(unsigned int datamode)
 {
-	if (datamode == EROFS_INODE_FLAT_COMPRESSION)
-		return true;
-	return datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY;
+	return datamode == EROFS_INODE_FLAT_COMPRESSION ||
+		datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY;
 }
 
 /* bit definitions of inode i_advise */
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH 06/21] erofs: kill erofs_{init,exit}_inode_cache
  2019-09-01  5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang
                     ` (4 preceding siblings ...)
  2019-09-01  5:51   ` [PATCH 05/21] erofs: update erofs_inode_is_data_compressed helper Gao Xiang
@ 2019-09-01  5:51   ` Gao Xiang
  2019-09-02 12:09     ` Christoph Hellwig
  2019-09-01  5:51   ` [PATCH 07/21] erofs: use erofs_inode naming Gao Xiang
                     ` (16 subsequent siblings)
  22 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-01  5:51 UTC (permalink / raw)
  To: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman
  Cc: linux-fsdevel, devel, linux-erofs, Chao Yu, Gao Xiang

From: Gao Xiang <gaoxiang25@huawei.com>

As Christoph said [1] "having this function seems
entirely pointless", let's kill those.

filesystem                              function name
ext2,f2fs,ext4,isofs,squashfs,cifs,...  init_inodecache

In addition, add a necessary "rcu_barrier()" on exit_fs();

[1] https://lore.kernel.org/r/20190829101545.GC20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/super.c | 31 ++++++++++++-------------------
 1 file changed, 12 insertions(+), 19 deletions(-)

diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 6603f0ba8905..0c412de33315 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -23,21 +23,6 @@ static void init_once(void *ptr)
 	inode_init_once(&vi->vfs_inode);
 }
 
-static int __init erofs_init_inode_cache(void)
-{
-	erofs_inode_cachep = kmem_cache_create("erofs_inode",
-					       sizeof(struct erofs_vnode), 0,
-					       SLAB_RECLAIM_ACCOUNT,
-					       init_once);
-
-	return erofs_inode_cachep ? 0 : -ENOMEM;
-}
-
-static void erofs_exit_inode_cache(void)
-{
-	kmem_cache_destroy(erofs_inode_cachep);
-}
-
 static struct inode *alloc_inode(struct super_block *sb)
 {
 	struct erofs_vnode *vi =
@@ -531,9 +516,14 @@ static int __init erofs_module_init(void)
 	erofs_check_ondisk_layout_definitions();
 	infoln("initializing erofs " EROFS_VERSION);
 
-	err = erofs_init_inode_cache();
-	if (err)
+	erofs_inode_cachep = kmem_cache_create("erofs_inode",
+					       sizeof(struct erofs_vnode), 0,
+					       SLAB_RECLAIM_ACCOUNT,
+					       init_once);
+	if (!erofs_inode_cachep) {
+		err = -ENOMEM;
 		goto icache_err;
+	}
 
 	err = erofs_init_shrinker();
 	if (err)
@@ -555,7 +545,7 @@ static int __init erofs_module_init(void)
 zip_err:
 	erofs_exit_shrinker();
 shrinker_err:
-	erofs_exit_inode_cache();
+	kmem_cache_destroy(erofs_inode_cachep);
 icache_err:
 	return err;
 }
@@ -565,7 +555,10 @@ static void __exit erofs_module_exit(void)
 	unregister_filesystem(&erofs_fs_type);
 	z_erofs_exit_zip_subsystem();
 	erofs_exit_shrinker();
-	erofs_exit_inode_cache();
+
+	/* Ensure all RCU free inodes are safe before cache is destroyed. */
+	rcu_barrier();
+	kmem_cache_destroy(erofs_inode_cachep);
 	infoln("successfully finalize erofs");
 }
 
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH 07/21] erofs: use erofs_inode naming
  2019-09-01  5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang
                     ` (5 preceding siblings ...)
  2019-09-01  5:51   ` [PATCH 06/21] erofs: kill erofs_{init,exit}_inode_cache Gao Xiang
@ 2019-09-01  5:51   ` Gao Xiang
  2019-09-02 12:10     ` Christoph Hellwig
  2019-09-01  5:51   ` [PATCH 08/21] erofs: update comments in inode.c Gao Xiang
                     ` (15 subsequent siblings)
  22 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-01  5:51 UTC (permalink / raw)
  To: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman
  Cc: linux-fsdevel, devel, linux-erofs, Chao Yu, Gao Xiang

From: Gao Xiang <gaoxiang25@huawei.com>

As Christoph suggested [1], "Why is this called vnode instead
of inode?  That seems like a rather odd naming for a Linux
file system."

[1] https://lore.kernel.org/r/20190829101545.GC20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/data.c              |  4 ++--
 fs/erofs/dir.c               |  6 +++---
 fs/erofs/inode.c             | 10 +++++-----
 fs/erofs/internal.h          | 18 +++++++++---------
 fs/erofs/namei.c             |  2 +-
 fs/erofs/super.c             | 12 +++++-------
 fs/erofs/xattr.c             | 18 +++++++++---------
 fs/erofs/xattr.h             |  4 ++--
 fs/erofs/zdata.c             |  9 +++------
 fs/erofs/zmap.c              | 28 ++++++++++++++--------------
 include/trace/events/erofs.h | 14 +++++++-------
 11 files changed, 60 insertions(+), 65 deletions(-)

diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index 0983807737fd..d736d2e551a1 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -112,7 +112,7 @@ static int erofs_map_blocks_flatmode(struct inode *inode,
 	int err = 0;
 	erofs_blk_t nblocks, lastblk;
 	u64 offset = map->m_la;
-	struct erofs_vnode *vi = EROFS_V(inode);
+	struct erofs_inode *vi = EROFS_I(inode);
 
 	trace_erofs_map_blocks_flatmode_enter(inode, map, flags);
 
@@ -364,7 +364,7 @@ static int erofs_raw_access_readpages(struct file *filp,
 			if (IS_ERR(bio)) {
 				pr_err("%s, readahead error at page %lu of nid %llu\n",
 				       __func__, page->index,
-				       EROFS_V(mapping->host)->nid);
+				       EROFS_I(mapping->host)->nid);
 
 				bio = NULL;
 			}
diff --git a/fs/erofs/dir.c b/fs/erofs/dir.c
index 6a5b43f7fb29..a032c8217071 100644
--- a/fs/erofs/dir.c
+++ b/fs/erofs/dir.c
@@ -47,7 +47,7 @@ static int erofs_fill_dentries(struct inode *dir, struct dir_context *ctx,
 		/* a corrupted entry is found */
 		if (nameoff + de_namelen > maxsize ||
 		    de_namelen > EROFS_NAME_LEN) {
-			errln("bogus dirent @ nid %llu", EROFS_V(dir)->nid);
+			errln("bogus dirent @ nid %llu", EROFS_I(dir)->nid);
 			DBG_BUGON(1);
 			return -EFSCORRUPTED;
 		}
@@ -85,7 +85,7 @@ static int erofs_readdir(struct file *f, struct dir_context *ctx)
 			break;
 		} else if (IS_ERR(dentry_page)) {
 			errln("fail to readdir of logical block %u of nid %llu",
-			      i, EROFS_V(dir)->nid);
+			      i, EROFS_I(dir)->nid);
 			err = -EFSCORRUPTED;
 			break;
 		}
@@ -97,7 +97,7 @@ static int erofs_readdir(struct file *f, struct dir_context *ctx)
 		if (nameoff < sizeof(struct erofs_dirent) ||
 		    nameoff >= PAGE_SIZE) {
 			errln("%s, invalid de[0].nameoff %u @ nid %llu",
-			      __func__, nameoff, EROFS_V(dir)->nid);
+			      __func__, nameoff, EROFS_I(dir)->nid);
 			err = -EFSCORRUPTED;
 			goto skip_this;
 		}
diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index 3fc4f764b387..de0373647959 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -11,7 +11,7 @@
 /* no locking */
 static int read_inode(struct inode *inode, void *data)
 {
-	struct erofs_vnode *vi = EROFS_V(inode);
+	struct erofs_inode *vi = EROFS_I(inode);
 	struct erofs_inode_v1 *v1 = data;
 	const unsigned int advise = le16_to_cpu(v1->i_advise);
 	erofs_blk_t nblks = 0;
@@ -122,7 +122,7 @@ static int read_inode(struct inode *inode, void *data)
 static int fill_inline_data(struct inode *inode, void *data,
 			    unsigned int m_pofs)
 {
-	struct erofs_vnode *vi = EROFS_V(inode);
+	struct erofs_inode *vi = EROFS_I(inode);
 	struct erofs_sb_info *sbi = EROFS_I_SB(inode);
 
 	/* should be inode inline C */
@@ -160,7 +160,7 @@ static int fill_inline_data(struct inode *inode, void *data,
 static int fill_inode(struct inode *inode, int isdir)
 {
 	struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
-	struct erofs_vnode *vi = EROFS_V(inode);
+	struct erofs_inode *vi = EROFS_I(inode);
 	struct page *page;
 	void *data;
 	int err;
@@ -242,7 +242,7 @@ static int erofs_ilookup_test_actor(struct inode *inode, void *opaque)
 {
 	const erofs_nid_t nid = *(erofs_nid_t *)opaque;
 
-	return EROFS_V(inode)->nid == nid;
+	return EROFS_I(inode)->nid == nid;
 }
 
 static int erofs_iget_set_actor(struct inode *inode, void *opaque)
@@ -279,7 +279,7 @@ struct inode *erofs_iget(struct super_block *sb,
 
 	if (inode->i_state & I_NEW) {
 		int err;
-		struct erofs_vnode *vi = EROFS_V(inode);
+		struct erofs_inode *vi = EROFS_I(inode);
 
 		vi->nid = nid;
 
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 141ea424587d..e576650bd4f4 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -272,14 +272,14 @@ static inline erofs_off_t iloc(struct erofs_sb_info *sbi, erofs_nid_t nid)
 }
 
 /* atomic flag definitions */
-#define EROFS_V_EA_INITED_BIT	0
-#define EROFS_V_Z_INITED_BIT	1
+#define EROFS_I_EA_INITED_BIT	0
+#define EROFS_I_Z_INITED_BIT	1
 
 /* bitlock definitions (arranged in reverse order) */
-#define EROFS_V_BL_XATTR_BIT	(BITS_PER_LONG - 1)
-#define EROFS_V_BL_Z_BIT	(BITS_PER_LONG - 2)
+#define EROFS_I_BL_XATTR_BIT	(BITS_PER_LONG - 1)
+#define EROFS_I_BL_Z_BIT	(BITS_PER_LONG - 2)
 
-struct erofs_vnode {
+struct erofs_inode {
 	erofs_nid_t nid;
 
 	/* atomic flags (including bitlocks) */
@@ -307,8 +307,8 @@ struct erofs_vnode {
 	struct inode vfs_inode;
 };
 
-#define EROFS_V(ptr)	\
-	container_of(ptr, struct erofs_vnode, vfs_inode)
+#define EROFS_I(ptr)	\
+	container_of(ptr, struct erofs_inode, vfs_inode)
 
 #define __inode_advise(x, bit, bits) \
 	(((x) >> (bit)) & ((1 << (bits)) - 1))
@@ -329,12 +329,12 @@ static inline unsigned long inode_datablocks(struct inode *inode)
 
 static inline bool is_inode_layout_compression(struct inode *inode)
 {
-	return erofs_inode_is_data_compressed(EROFS_V(inode)->datamode);
+	return erofs_inode_is_data_compressed(EROFS_I(inode)->datamode);
 }
 
 static inline bool is_inode_flat_inline(struct inode *inode)
 {
-	return EROFS_V(inode)->datamode == EROFS_INODE_FLAT_INLINE;
+	return EROFS_I(inode)->datamode == EROFS_INODE_FLAT_INLINE;
 }
 
 extern const struct super_operations erofs_sops;
diff --git a/fs/erofs/namei.c b/fs/erofs/namei.c
index c1068ad0535e..a6b6a4ab1403 100644
--- a/fs/erofs/namei.c
+++ b/fs/erofs/namei.c
@@ -117,7 +117,7 @@ static struct page *find_target_block_classic(struct inode *dir,
 				kunmap_atomic(de);
 				put_page(page);
 				errln("corrupted dir block %d @ nid %llu",
-				      mid, EROFS_V(dir)->nid);
+				      mid, EROFS_I(dir)->nid);
 				DBG_BUGON(1);
 				page = ERR_PTR(-EFSCORRUPTED);
 				goto out;
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 0c412de33315..b0d318a8eb22 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -18,27 +18,25 @@ static struct kmem_cache *erofs_inode_cachep __read_mostly;
 
 static void init_once(void *ptr)
 {
-	struct erofs_vnode *vi = ptr;
-
-	inode_init_once(&vi->vfs_inode);
+	inode_init_once(&((struct erofs_inode *)ptr)->vfs_inode);
 }
 
 static struct inode *alloc_inode(struct super_block *sb)
 {
-	struct erofs_vnode *vi =
+	struct erofs_inode *vi =
 		kmem_cache_alloc(erofs_inode_cachep, GFP_KERNEL);
 
 	if (!vi)
 		return NULL;
 
 	/* zero out everything except vfs_inode */
-	memset(vi, 0, offsetof(struct erofs_vnode, vfs_inode));
+	memset(vi, 0, offsetof(struct erofs_inode, vfs_inode));
 	return &vi->vfs_inode;
 }
 
 static void free_inode(struct inode *inode)
 {
-	struct erofs_vnode *vi = EROFS_V(inode);
+	struct erofs_inode *vi = EROFS_I(inode);
 
 	/* be careful RCU symlink path (see ext4_inode_info->i_data)! */
 	if (is_inode_fast_symlink(inode))
@@ -517,7 +515,7 @@ static int __init erofs_module_init(void)
 	infoln("initializing erofs " EROFS_VERSION);
 
 	erofs_inode_cachep = kmem_cache_create("erofs_inode",
-					       sizeof(struct erofs_vnode), 0,
+					       sizeof(struct erofs_inode), 0,
 					       SLAB_RECLAIM_ACCOUNT,
 					       init_once);
 	if (!erofs_inode_cachep) {
diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c
index 620cbc15f4d0..d5b7fe0bee45 100644
--- a/fs/erofs/xattr.c
+++ b/fs/erofs/xattr.c
@@ -38,7 +38,7 @@ static inline void xattr_iter_end_final(struct xattr_iter *it)
 
 static int init_inode_xattrs(struct inode *inode)
 {
-	struct erofs_vnode *const vi = EROFS_V(inode);
+	struct erofs_inode *const vi = EROFS_I(inode);
 	struct xattr_iter it;
 	unsigned int i;
 	struct erofs_xattr_ibody_header *ih;
@@ -48,14 +48,14 @@ static int init_inode_xattrs(struct inode *inode)
 	int ret = 0;
 
 	/* the most case is that xattrs of this inode are initialized. */
-	if (test_bit(EROFS_V_EA_INITED_BIT, &vi->flags))
+	if (test_bit(EROFS_I_EA_INITED_BIT, &vi->flags))
 		return 0;
 
-	if (wait_on_bit_lock(&vi->flags, EROFS_V_BL_XATTR_BIT, TASK_KILLABLE))
+	if (wait_on_bit_lock(&vi->flags, EROFS_I_BL_XATTR_BIT, TASK_KILLABLE))
 		return -ERESTARTSYS;
 
 	/* someone has initialized xattrs for us? */
-	if (test_bit(EROFS_V_EA_INITED_BIT, &vi->flags))
+	if (test_bit(EROFS_I_EA_INITED_BIT, &vi->flags))
 		goto out_unlock;
 
 	/*
@@ -136,10 +136,10 @@ static int init_inode_xattrs(struct inode *inode)
 	}
 	xattr_iter_end(&it, atomic_map);
 
-	set_bit(EROFS_V_EA_INITED_BIT, &vi->flags);
+	set_bit(EROFS_I_EA_INITED_BIT, &vi->flags);
 
 out_unlock:
-	clear_and_wake_up_bit(EROFS_V_BL_XATTR_BIT, &vi->flags);
+	clear_and_wake_up_bit(EROFS_I_BL_XATTR_BIT, &vi->flags);
 	return ret;
 }
 
@@ -184,7 +184,7 @@ static inline int xattr_iter_fixup(struct xattr_iter *it)
 static int inline_xattr_iter_begin(struct xattr_iter *it,
 				   struct inode *inode)
 {
-	struct erofs_vnode *const vi = EROFS_V(inode);
+	struct erofs_inode *const vi = EROFS_I(inode);
 	struct erofs_sb_info *const sbi = EROFS_SB(inode->i_sb);
 	unsigned int xattr_header_sz, inline_xattr_ofs;
 
@@ -385,7 +385,7 @@ static int inline_getxattr(struct inode *inode, struct getxattr_iter *it)
 
 static int shared_getxattr(struct inode *inode, struct getxattr_iter *it)
 {
-	struct erofs_vnode *const vi = EROFS_V(inode);
+	struct erofs_inode *const vi = EROFS_I(inode);
 	struct super_block *const sb = inode->i_sb;
 	struct erofs_sb_info *const sbi = EROFS_SB(sb);
 	unsigned int i;
@@ -608,7 +608,7 @@ static int inline_listxattr(struct listxattr_iter *it)
 static int shared_listxattr(struct listxattr_iter *it)
 {
 	struct inode *const inode = d_inode(it->dentry);
-	struct erofs_vnode *const vi = EROFS_V(inode);
+	struct erofs_inode *const vi = EROFS_I(inode);
 	struct super_block *const sb = inode->i_sb;
 	struct erofs_sb_info *const sbi = EROFS_SB(sb);
 	unsigned int i;
diff --git a/fs/erofs/xattr.h b/fs/erofs/xattr.h
index c5ca47d814dd..3585b84d2f20 100644
--- a/fs/erofs/xattr.h
+++ b/fs/erofs/xattr.h
@@ -16,8 +16,8 @@
 
 static inline unsigned int inlinexattr_header_size(struct inode *inode)
 {
-	return sizeof(struct erofs_xattr_ibody_header)
-		+ sizeof(u32) * EROFS_V(inode)->xattr_shared_count;
+	return sizeof(struct erofs_xattr_ibody_header) +
+		sizeof(u32) * EROFS_I(inode)->xattr_shared_count;
 }
 
 static inline erofs_blk_t xattrblock_addr(struct erofs_sb_info *sbi,
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index 653bde0a619a..f06a2fad7af2 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -421,7 +421,7 @@ static struct z_erofs_collection *clregister(struct z_erofs_collector *clt,
 	else
 		pcl->algorithmformat = Z_EROFS_COMPRESSION_SHIFTED;
 
-	pcl->clusterbits = EROFS_V(inode)->z_physical_clusterbits[0];
+	pcl->clusterbits = EROFS_I(inode)->z_physical_clusterbits[0];
 	pcl->clusterbits -= PAGE_SHIFT;
 
 	/* new pclusters should be claimed as type 1, primary and followed */
@@ -1404,12 +1404,9 @@ static int z_erofs_vle_normalaccess_readpages(struct file *filp,
 		head = (void *)page_private(page);
 
 		err = z_erofs_do_read_page(&f, page, &pagepool);
-		if (err) {
-			struct erofs_vnode *vi = EROFS_V(inode);
-
+		if (err)
 			errln("%s, readahead error at page %lu of nid %llu",
-			      __func__, page->index, vi->nid);
-		}
+			      __func__, page->index, EROFS_I(inode)->nid);
 		put_page(page);
 	}
 
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index 850e0e3d57a8..c2dd778ebdd3 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -10,7 +10,7 @@
 
 int z_erofs_fill_inode(struct inode *inode)
 {
-	struct erofs_vnode *const vi = EROFS_V(inode);
+	struct erofs_inode *const vi = EROFS_I(inode);
 
 	if (vi->datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY) {
 		vi->z_advise = 0;
@@ -19,7 +19,7 @@ int z_erofs_fill_inode(struct inode *inode)
 		vi->z_logical_clusterbits = LOG_BLOCK_SIZE;
 		vi->z_physical_clusterbits[0] = vi->z_logical_clusterbits;
 		vi->z_physical_clusterbits[1] = vi->z_logical_clusterbits;
-		set_bit(EROFS_V_Z_INITED_BIT, &vi->flags);
+		set_bit(EROFS_I_Z_INITED_BIT, &vi->flags);
 	}
 
 	inode->i_mapping->a_ops = &z_erofs_vle_normalaccess_aops;
@@ -28,7 +28,7 @@ int z_erofs_fill_inode(struct inode *inode)
 
 static int fill_inode_lazy(struct inode *inode)
 {
-	struct erofs_vnode *const vi = EROFS_V(inode);
+	struct erofs_inode *const vi = EROFS_I(inode);
 	struct super_block *const sb = inode->i_sb;
 	int err;
 	erofs_off_t pos;
@@ -36,14 +36,14 @@ static int fill_inode_lazy(struct inode *inode)
 	void *kaddr;
 	struct z_erofs_map_header *h;
 
-	if (test_bit(EROFS_V_Z_INITED_BIT, &vi->flags))
+	if (test_bit(EROFS_I_Z_INITED_BIT, &vi->flags))
 		return 0;
 
-	if (wait_on_bit_lock(&vi->flags, EROFS_V_BL_Z_BIT, TASK_KILLABLE))
+	if (wait_on_bit_lock(&vi->flags, EROFS_I_BL_Z_BIT, TASK_KILLABLE))
 		return -ERESTARTSYS;
 
 	err = 0;
-	if (test_bit(EROFS_V_Z_INITED_BIT, &vi->flags))
+	if (test_bit(EROFS_I_Z_INITED_BIT, &vi->flags))
 		goto out_unlock;
 
 	DBG_BUGON(vi->datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY);
@@ -83,13 +83,13 @@ static int fill_inode_lazy(struct inode *inode)
 
 	vi->z_physical_clusterbits[1] = vi->z_logical_clusterbits +
 					((h->h_clusterbits >> 5) & 7);
-	set_bit(EROFS_V_Z_INITED_BIT, &vi->flags);
+	set_bit(EROFS_I_Z_INITED_BIT, &vi->flags);
 unmap_done:
 	kunmap_atomic(kaddr);
 	unlock_page(page);
 	put_page(page);
 out_unlock:
-	clear_and_wake_up_bit(EROFS_V_BL_Z_BIT, &vi->flags);
+	clear_and_wake_up_bit(EROFS_I_BL_Z_BIT, &vi->flags);
 	return err;
 }
 
@@ -142,7 +142,7 @@ static int vle_legacy_load_cluster_from_disk(struct z_erofs_maprecorder *m,
 					     unsigned long lcn)
 {
 	struct inode *const inode = m->inode;
-	struct erofs_vnode *const vi = EROFS_V(inode);
+	struct erofs_inode *const vi = EROFS_I(inode);
 	const erofs_off_t ibase = iloc(EROFS_I_SB(inode), vi->nid);
 	const erofs_off_t pos =
 		Z_EROFS_VLE_LEGACY_INDEX_ALIGN(ibase + vi->inode_isize +
@@ -196,7 +196,7 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m,
 				  unsigned int amortizedshift,
 				  unsigned int eofs)
 {
-	struct erofs_vnode *const vi = EROFS_V(m->inode);
+	struct erofs_inode *const vi = EROFS_I(m->inode);
 	const unsigned int lclusterbits = vi->z_logical_clusterbits;
 	const unsigned int lomask = (1 << lclusterbits) - 1;
 	unsigned int vcnt, base, lo, encodebits, nblk;
@@ -260,7 +260,7 @@ static int compacted_load_cluster_from_disk(struct z_erofs_maprecorder *m,
 					    unsigned long lcn)
 {
 	struct inode *const inode = m->inode;
-	struct erofs_vnode *const vi = EROFS_V(inode);
+	struct erofs_inode *const vi = EROFS_I(inode);
 	const unsigned int lclusterbits = vi->z_logical_clusterbits;
 	const erofs_off_t ebase = ALIGN(iloc(EROFS_I_SB(inode), vi->nid) +
 					vi->inode_isize + vi->xattr_isize, 8) +
@@ -314,7 +314,7 @@ static int compacted_load_cluster_from_disk(struct z_erofs_maprecorder *m,
 static int vle_load_cluster_from_disk(struct z_erofs_maprecorder *m,
 				      unsigned int lcn)
 {
-	const unsigned int datamode = EROFS_V(m->inode)->datamode;
+	const unsigned int datamode = EROFS_I(m->inode)->datamode;
 
 	if (datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY)
 		return vle_legacy_load_cluster_from_disk(m, lcn);
@@ -328,7 +328,7 @@ static int vle_load_cluster_from_disk(struct z_erofs_maprecorder *m,
 static int vle_extent_lookback(struct z_erofs_maprecorder *m,
 			       unsigned int lookback_distance)
 {
-	struct erofs_vnode *const vi = EROFS_V(m->inode);
+	struct erofs_inode *const vi = EROFS_I(m->inode);
 	struct erofs_map_blocks *const map = m->map;
 	const unsigned int lclusterbits = vi->z_logical_clusterbits;
 	unsigned long lcn = m->lcn;
@@ -374,7 +374,7 @@ int z_erofs_map_blocks_iter(struct inode *inode,
 			    struct erofs_map_blocks *map,
 			    int flags)
 {
-	struct erofs_vnode *const vi = EROFS_V(inode);
+	struct erofs_inode *const vi = EROFS_I(inode);
 	struct z_erofs_maprecorder m = {
 		.inode = inode,
 		.map = map,
diff --git a/include/trace/events/erofs.h b/include/trace/events/erofs.h
index d239f39cbc8c..27f5caa6299a 100644
--- a/include/trace/events/erofs.h
+++ b/include/trace/events/erofs.h
@@ -41,7 +41,7 @@ TRACE_EVENT(erofs_lookup,
 
 	TP_fast_assign(
 		__entry->dev	= dir->i_sb->s_dev;
-		__entry->nid	= EROFS_V(dir)->nid;
+		__entry->nid	= EROFS_I(dir)->nid;
 		__entry->name	= dentry->d_name.name;
 		__entry->flags	= flags;
 	),
@@ -66,7 +66,7 @@ TRACE_EVENT(erofs_fill_inode,
 
 	TP_fast_assign(
 		__entry->dev		= inode->i_sb->s_dev;
-		__entry->nid		= EROFS_V(inode)->nid;
+		__entry->nid		= EROFS_I(inode)->nid;
 		__entry->blkaddr	= erofs_blknr(iloc(EROFS_I_SB(inode), __entry->nid));
 		__entry->ofs		= erofs_blkoff(iloc(EROFS_I_SB(inode), __entry->nid));
 		__entry->isdir		= isdir;
@@ -95,7 +95,7 @@ TRACE_EVENT(erofs_readpage,
 
 	TP_fast_assign(
 		__entry->dev	= page->mapping->host->i_sb->s_dev;
-		__entry->nid	= EROFS_V(page->mapping->host)->nid;
+		__entry->nid	= EROFS_I(page->mapping->host)->nid;
 		__entry->dir	= S_ISDIR(page->mapping->host->i_mode);
 		__entry->index	= page->index;
 		__entry->uptodate = PageUptodate(page);
@@ -128,7 +128,7 @@ TRACE_EVENT(erofs_readpages,
 
 	TP_fast_assign(
 		__entry->dev	= inode->i_sb->s_dev;
-		__entry->nid	= EROFS_V(inode)->nid;
+		__entry->nid	= EROFS_I(inode)->nid;
 		__entry->start	= page->index;
 		__entry->nrpage	= nrpage;
 		__entry->raw	= raw;
@@ -157,7 +157,7 @@ DECLARE_EVENT_CLASS(erofs__map_blocks_enter,
 
 	TP_fast_assign(
 		__entry->dev    = inode->i_sb->s_dev;
-		__entry->nid    = EROFS_V(inode)->nid;
+		__entry->nid    = EROFS_I(inode)->nid;
 		__entry->la	= map->m_la;
 		__entry->llen	= map->m_llen;
 		__entry->flags	= flags;
@@ -203,7 +203,7 @@ DECLARE_EVENT_CLASS(erofs__map_blocks_exit,
 
 	TP_fast_assign(
 		__entry->dev    = inode->i_sb->s_dev;
-		__entry->nid    = EROFS_V(inode)->nid;
+		__entry->nid    = EROFS_I(inode)->nid;
 		__entry->flags	= flags;
 		__entry->la	= map->m_la;
 		__entry->pa	= map->m_pa;
@@ -247,7 +247,7 @@ TRACE_EVENT(erofs_destroy_inode,
 
 	TP_fast_assign(
 		__entry->dev	= inode->i_sb->s_dev;
-		__entry->nid	= EROFS_V(inode)->nid;
+		__entry->nid	= EROFS_I(inode)->nid;
 	),
 
 	TP_printk("dev = (%d,%d), nid = %llu", show_dev_nid(__entry))
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH 08/21] erofs: update comments in inode.c
  2019-09-01  5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang
                     ` (6 preceding siblings ...)
  2019-09-01  5:51   ` [PATCH 07/21] erofs: use erofs_inode naming Gao Xiang
@ 2019-09-01  5:51   ` Gao Xiang
  2019-09-01  5:51   ` [PATCH 09/21] erofs: update erofs symlink stuffs Gao Xiang
                     ` (14 subsequent siblings)
  22 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-01  5:51 UTC (permalink / raw)
  To: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman
  Cc: linux-fsdevel, devel, linux-erofs, Chao Yu, Gao Xiang

From: Gao Xiang <gaoxiang25@huawei.com>

As Christoph suggested [1], update them all.

[1] https://lore.kernel.org/r/20190829102426.GE20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/inode.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index de0373647959..24c94a7865f2 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -129,7 +129,7 @@ static int fill_inline_data(struct inode *inode, void *data,
 	if (!is_inode_flat_inline(inode))
 		return 0;
 
-	/* fast symlink (following ext4) */
+	/* fast symlink */
 	if (S_ISLNK(inode->i_mode) && inode->i_size < PAGE_SIZE) {
 		char *lnk = erofs_kmalloc(sbi, inode->i_size + 1, GFP_KERNEL);
 
@@ -138,7 +138,7 @@ static int fill_inline_data(struct inode *inode, void *data,
 
 		m_pofs += vi->inode_isize + vi->xattr_isize;
 
-		/* inline symlink data shouldn't across page boundary as well */
+		/* inline symlink data shouldn't cross page boundary as well */
 		if (m_pofs + inode->i_size > PAGE_SIZE) {
 			kfree(lnk);
 			errln("inline data cross block boundary @ nid %llu",
@@ -147,7 +147,6 @@ static int fill_inline_data(struct inode *inode, void *data,
 			return -EFSCORRUPTED;
 		}
 
-		/* get in-page inline data */
 		memcpy(lnk, data + m_pofs, inode->i_size);
 		lnk[inode->i_size] = '\0';
 
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH 09/21] erofs: update erofs symlink stuffs
  2019-09-01  5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang
                     ` (7 preceding siblings ...)
  2019-09-01  5:51   ` [PATCH 08/21] erofs: update comments in inode.c Gao Xiang
@ 2019-09-01  5:51   ` Gao Xiang
  2019-09-02 12:11     ` Christoph Hellwig
  2019-09-01  5:51   ` [PATCH 10/21] erofs: kill is_inode_layout_compression() Gao Xiang
                     ` (13 subsequent siblings)
  22 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-01  5:51 UTC (permalink / raw)
  To: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman
  Cc: linux-fsdevel, devel, linux-erofs, Chao Yu, Gao Xiang

From: Gao Xiang <gaoxiang25@huawei.com>

Fix as Christoph suggested [1] [2], "remove is_inode_fast_symlink
and just opencode it in the few places using it"

and
"Please just set the ops directly instead of obsfucating that in
a single caller, single line inline function.  And please set it
instead of the normal symlink iops in the same place where you
also set those."

[1] https://lore.kernel.org/r/20190830163910.GB29603@infradead.org/
[2] https://lore.kernel.org/r/20190829102426.GE20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/inode.c    | 35 ++++++++++-------------------------
 fs/erofs/internal.h | 10 ----------
 fs/erofs/super.c    |  5 ++---
 3 files changed, 12 insertions(+), 38 deletions(-)

diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index 24c94a7865f2..29a52138fa9d 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -109,28 +109,14 @@ static int read_inode(struct inode *inode, void *data)
 	return -EFSCORRUPTED;
 }
 
-/*
- * try_lock can be required since locking order is:
- *   file data(fs_inode)
- *        meta(bd_inode)
- * but the majority of the callers is "iget",
- * in that case we are pretty sure no deadlock since
- * no data operations exist. However I tend to
- * try_lock since it takes no much overhead and
- * will success immediately.
- */
-static int fill_inline_data(struct inode *inode, void *data,
-			    unsigned int m_pofs)
+static int erofs_fill_symlink(struct inode *inode, void *data,
+			      unsigned int m_pofs)
 {
 	struct erofs_inode *vi = EROFS_I(inode);
 	struct erofs_sb_info *sbi = EROFS_I_SB(inode);
 
-	/* should be inode inline C */
-	if (!is_inode_flat_inline(inode))
-		return 0;
-
-	/* fast symlink */
-	if (S_ISLNK(inode->i_mode) && inode->i_size < PAGE_SIZE) {
+	/* if it can be handled with fast symlink scheme */
+	if (is_inode_flat_inline(inode) && inode->i_size < PAGE_SIZE) {
 		char *lnk = erofs_kmalloc(sbi, inode->i_size + 1, GFP_KERNEL);
 
 		if (!lnk)
@@ -151,7 +137,9 @@ static int fill_inline_data(struct inode *inode, void *data,
 		lnk[inode->i_size] = '\0';
 
 		inode->i_link = lnk;
-		set_inode_fast_symlink(inode);
+		inode->i_op = &erofs_fast_symlink_iops;
+	} else {
+		inode->i_op = &erofs_symlink_iops;
 	}
 	return 0;
 }
@@ -199,8 +187,9 @@ static int fill_inode(struct inode *inode, int isdir)
 			inode->i_fop = &erofs_dir_fops;
 			break;
 		case S_IFLNK:
-			/* by default, page_get_link is used for symlink */
-			inode->i_op = &erofs_symlink_iops;
+			err = erofs_fill_symlink(inode, data, ofs);
+			if (err)
+				goto out_unlock;
 			inode_nohighmem(inode);
 			break;
 		case S_IFCHR:
@@ -219,11 +208,7 @@ static int fill_inode(struct inode *inode, int isdir)
 			err = z_erofs_fill_inode(inode);
 			goto out_unlock;
 		}
-
 		inode->i_mapping->a_ops = &erofs_raw_access_aops;
-
-		/* fill last page if inline data is available */
-		err = fill_inline_data(inode, data, ofs);
 	}
 
 out_unlock:
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index e576650bd4f4..4442a6622504 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -480,16 +480,6 @@ extern const struct inode_operations erofs_generic_iops;
 extern const struct inode_operations erofs_symlink_iops;
 extern const struct inode_operations erofs_fast_symlink_iops;
 
-static inline void set_inode_fast_symlink(struct inode *inode)
-{
-	inode->i_op = &erofs_fast_symlink_iops;
-}
-
-static inline bool is_inode_fast_symlink(struct inode *inode)
-{
-	return inode->i_op == &erofs_fast_symlink_iops;
-}
-
 struct inode *erofs_iget(struct super_block *sb, erofs_nid_t nid, bool dir);
 int erofs_getattr(const struct path *path, struct kstat *stat,
 		  u32 request_mask, unsigned int query_flags);
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index b0d318a8eb22..8c43af5d5e57 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -38,10 +38,9 @@ static void free_inode(struct inode *inode)
 {
 	struct erofs_inode *vi = EROFS_I(inode);
 
-	/* be careful RCU symlink path (see ext4_inode_info->i_data)! */
-	if (is_inode_fast_symlink(inode))
+	/* be careful of RCU symlink path */
+	if (inode->i_op == &erofs_fast_symlink_iops)
 		kfree(inode->i_link);
-
 	kfree(vi->xattr_shared_xattrs);
 
 	kmem_cache_free(erofs_inode_cachep, vi);
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH 10/21] erofs: kill is_inode_layout_compression()
  2019-09-01  5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang
                     ` (8 preceding siblings ...)
  2019-09-01  5:51   ` [PATCH 09/21] erofs: update erofs symlink stuffs Gao Xiang
@ 2019-09-01  5:51   ` Gao Xiang
  2019-09-02 12:11     ` Christoph Hellwig
  2019-09-01  5:51   ` [PATCH 11/21] erofs: use dsb instead of layout for ondisk super_block Gao Xiang
                     ` (12 subsequent siblings)
  22 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-01  5:51 UTC (permalink / raw)
  To: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman
  Cc: linux-fsdevel, devel, linux-erofs, Chao Yu, Gao Xiang

From: Gao Xiang <gaoxiang25@huawei.com>

As Christoph suggested [1], "The name of this helper
is a little odd.  But I think just opencoding it seems
generally cleaner anyway. "

[1] https://lore.kernel.org/r/20190829102426.GE20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/data.c     | 2 +-
 fs/erofs/inode.c    | 8 ++++----
 fs/erofs/internal.h | 5 -----
 3 files changed, 5 insertions(+), 10 deletions(-)

diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index d736d2e551a1..e2e40ec2bfd1 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -169,7 +169,7 @@ static int erofs_map_blocks_flatmode(struct inode *inode,
 int erofs_map_blocks(struct inode *inode,
 		     struct erofs_map_blocks *map, int flags)
 {
-	if (is_inode_layout_compression(inode)) {
+	if (erofs_inode_is_data_compressed(EROFS_I(inode)->datamode)) {
 		int err = z_erofs_map_blocks_iter(inode, map, flags);
 
 		if (map->mpage) {
diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index 29a52138fa9d..d501ceb62c29 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -56,7 +56,7 @@ static int read_inode(struct inode *inode, void *data)
 		inode->i_size = le64_to_cpu(v2->i_size);
 
 		/* total blocks for compressed files */
-		if (is_inode_layout_compression(inode))
+		if (erofs_inode_is_data_compressed(vi->datamode))
 			nblks = le32_to_cpu(v2->i_u.compressed_blocks);
 	} else if (__inode_version(advise) == EROFS_INODE_LAYOUT_V1) {
 		struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
@@ -87,7 +87,7 @@ static int read_inode(struct inode *inode, void *data)
 			sbi->build_time_nsec;
 
 		inode->i_size = le32_to_cpu(v1->i_size);
-		if (is_inode_layout_compression(inode))
+		if (erofs_inode_is_data_compressed(vi->datamode))
 			nblks = le32_to_cpu(v1->i_u.compressed_blocks);
 	} else {
 		errln("unsupported on-disk inode version %u of nid %llu",
@@ -204,7 +204,7 @@ static int fill_inode(struct inode *inode, int isdir)
 			goto out_unlock;
 		}
 
-		if (is_inode_layout_compression(inode)) {
+		if (erofs_inode_is_data_compressed(vi->datamode)) {
 			err = z_erofs_fill_inode(inode);
 			goto out_unlock;
 		}
@@ -283,7 +283,7 @@ int erofs_getattr(const struct path *path, struct kstat *stat,
 {
 	struct inode *const inode = d_inode(path->dentry);
 
-	if (is_inode_layout_compression(inode))
+	if (erofs_inode_is_data_compressed(EROFS_I(inode)->datamode))
 		stat->attributes |= STATX_ATTR_COMPRESSED;
 
 	stat->attributes |= STATX_ATTR_IMMUTABLE;
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 4442a6622504..6bd82a82b11f 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -327,11 +327,6 @@ static inline unsigned long inode_datablocks(struct inode *inode)
 	return DIV_ROUND_UP(inode->i_size, EROFS_BLKSIZ);
 }
 
-static inline bool is_inode_layout_compression(struct inode *inode)
-{
-	return erofs_inode_is_data_compressed(EROFS_I(inode)->datamode);
-}
-
 static inline bool is_inode_flat_inline(struct inode *inode)
 {
 	return EROFS_I(inode)->datamode == EROFS_INODE_FLAT_INLINE;
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH 11/21] erofs: use dsb instead of layout for ondisk super_block
  2019-09-01  5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang
                     ` (9 preceding siblings ...)
  2019-09-01  5:51   ` [PATCH 10/21] erofs: kill is_inode_layout_compression() Gao Xiang
@ 2019-09-01  5:51   ` Gao Xiang
  2019-09-02 12:12     ` Christoph Hellwig
  2019-09-01  5:51   ` [PATCH 12/21] erofs: kill verbose debug info in erofs_fill_super Gao Xiang
                     ` (11 subsequent siblings)
  22 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-01  5:51 UTC (permalink / raw)
  To: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman
  Cc: linux-fsdevel, devel, linux-erofs, Chao Yu, Gao Xiang

From: Gao Xiang <gaoxiang25@huawei.com>

As Christoph pointed out [1], "Why is the variable name
for the on-disk subperblock layout? We usually still
calls this something with sb in the name, e.g. dsb.
for disksuper block. " Let's fix it.

[1] https://lore.kernel.org/r/20190829101545.GC20598@infradead.org/
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/super.c | 36 ++++++++++++++++++------------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 8c43af5d5e57..c1a42ea7b72f 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -47,9 +47,9 @@ static void free_inode(struct inode *inode)
 }
 
 static bool check_layout_compatibility(struct super_block *sb,
-				       struct erofs_super_block *layout)
+				       struct erofs_super_block *dsb)
 {
-	const unsigned int requirements = le32_to_cpu(layout->requirements);
+	const unsigned int requirements = le32_to_cpu(dsb->requirements);
 
 	EROFS_SB(sb)->requirements = requirements;
 
@@ -66,7 +66,7 @@ static int superblock_read(struct super_block *sb)
 {
 	struct erofs_sb_info *sbi;
 	struct buffer_head *bh;
-	struct erofs_super_block *layout;
+	struct erofs_super_block *dsb;
 	unsigned int blkszbits;
 	int ret;
 
@@ -78,16 +78,16 @@ static int superblock_read(struct super_block *sb)
 	}
 
 	sbi = EROFS_SB(sb);
-	layout = (struct erofs_super_block *)((u8 *)bh->b_data
-		 + EROFS_SUPER_OFFSET);
+	dsb = (struct erofs_super_block *)((u8 *)bh->b_data +
+					   EROFS_SUPER_OFFSET);
 
 	ret = -EINVAL;
-	if (le32_to_cpu(layout->magic) != EROFS_SUPER_MAGIC_V1) {
+	if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) {
 		errln("cannot find valid erofs superblock");
 		goto out;
 	}
 
-	blkszbits = layout->blkszbits;
+	blkszbits = dsb->blkszbits;
 	/* 9(512 bytes) + LOG_SECTORS_PER_BLOCK == LOG_BLOCK_SIZE */
 	if (blkszbits != LOG_BLOCK_SIZE) {
 		errln("blksize %u isn't supported on this platform",
@@ -95,25 +95,25 @@ static int superblock_read(struct super_block *sb)
 		goto out;
 	}
 
-	if (!check_layout_compatibility(sb, layout))
+	if (!check_layout_compatibility(sb, dsb))
 		goto out;
 
-	sbi->blocks = le32_to_cpu(layout->blocks);
-	sbi->meta_blkaddr = le32_to_cpu(layout->meta_blkaddr);
+	sbi->blocks = le32_to_cpu(dsb->blocks);
+	sbi->meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr);
 #ifdef CONFIG_EROFS_FS_XATTR
-	sbi->xattr_blkaddr = le32_to_cpu(layout->xattr_blkaddr);
+	sbi->xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr);
 #endif
 	sbi->islotbits = ffs(sizeof(struct erofs_inode_v1)) - 1;
-	sbi->root_nid = le16_to_cpu(layout->root_nid);
-	sbi->inos = le64_to_cpu(layout->inos);
+	sbi->root_nid = le16_to_cpu(dsb->root_nid);
+	sbi->inos = le64_to_cpu(dsb->inos);
 
-	sbi->build_time = le64_to_cpu(layout->build_time);
-	sbi->build_time_nsec = le32_to_cpu(layout->build_time_nsec);
+	sbi->build_time = le64_to_cpu(dsb->build_time);
+	sbi->build_time_nsec = le32_to_cpu(dsb->build_time_nsec);
 
-	memcpy(&sb->s_uuid, layout->uuid, sizeof(layout->uuid));
+	memcpy(&sb->s_uuid, dsb->uuid, sizeof(dsb->uuid));
 
-	ret = strscpy(sbi->volume_name, layout->volume_name,
-		      sizeof(layout->volume_name));
+	ret = strscpy(sbi->volume_name, dsb->volume_name,
+		      sizeof(dsb->volume_name));
 	if (ret < 0) {	/* -E2BIG */
 		errln("bad volume name without NIL terminator");
 		ret = -EFSCORRUPTED;
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH 12/21] erofs: kill verbose debug info in erofs_fill_super
  2019-09-01  5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang
                     ` (10 preceding siblings ...)
  2019-09-01  5:51   ` [PATCH 11/21] erofs: use dsb instead of layout for ondisk super_block Gao Xiang
@ 2019-09-01  5:51   ` Gao Xiang
  2019-09-02 12:14     ` Christoph Hellwig
  2019-09-01  5:51   ` [PATCH 13/21] erofs: simplify erofs_grab_bio() since bio_alloc() never fail Gao Xiang
                     ` (10 subsequent siblings)
  22 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-01  5:51 UTC (permalink / raw)
  To: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman
  Cc: linux-fsdevel, devel, linux-erofs, Chao Yu, Gao Xiang

From: Gao Xiang <gaoxiang25@huawei.com>

As Christoph said [1], "That is some very verbose
debug info.  We usually don't add that and let
people trace the function instead. "

[1] https://lore.kernel.org/r/20190829101545.GC20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/super.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index c1a42ea7b72f..b4bf72755300 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -383,9 +383,6 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
 	struct erofs_sb_info *sbi;
 	int err;
 
-	infoln("fill_super, device -> %s", sb->s_id);
-	infoln("options -> %s", (char *)data);
-
 	sb->s_magic = EROFS_SUPER_MAGIC;
 
 	if (!sb_set_blocksize(sb, EROFS_BLKSIZ)) {
@@ -418,9 +415,6 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
 	if (err)
 		return err;
 
-	if (!silent)
-		infoln("root inode @ nid %llu", ROOT_NID(sbi));
-
 	if (test_opt(sbi, POSIX_ACL))
 		sb->s_flags |= SB_POSIXACL;
 	else
@@ -453,7 +447,8 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
 		return err;
 
 	if (!silent)
-		infoln("mounted on %s with opts: %s.", sb->s_id, (char *)data);
+		infoln("mounted on %s with opts: %s, root inode @ nid %llu.",
+		       sb->s_id, (char *)data, ROOT_NID(sbi));
 	return 0;
 }
 
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH 13/21] erofs: simplify erofs_grab_bio() since bio_alloc() never fail
  2019-09-01  5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang
                     ` (11 preceding siblings ...)
  2019-09-01  5:51   ` [PATCH 12/21] erofs: kill verbose debug info in erofs_fill_super Gao Xiang
@ 2019-09-01  5:51   ` Gao Xiang
  2019-09-02 12:20     ` Christoph Hellwig
  2019-09-01  5:51   ` [PATCH 14/21] erofs: kill prio and nofail of erofs_get_meta_page() Gao Xiang
                     ` (9 subsequent siblings)
  22 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-01  5:51 UTC (permalink / raw)
  To: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman
  Cc: linux-fsdevel, devel, linux-erofs, Chao Yu, Gao Xiang

From: Gao Xiang <gaoxiang25@huawei.com>

As Christoph pointed out [1], "erofs_grab_bio tries to
handle a bio_alloc failure, except that the function will
not actually fail due the mempool backing it."

Sorry about useless code, fix it now.

[1] https://lore.kernel.org/lkml/20190830162812.GA10694@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/data.c     | 15 ++-------------
 fs/erofs/internal.h | 19 ++-----------------
 fs/erofs/zdata.c    |  2 +-
 3 files changed, 5 insertions(+), 31 deletions(-)

diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index e2e40ec2bfd1..621954d4fb09 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -62,12 +62,7 @@ struct page *__erofs_get_meta_page(struct super_block *sb,
 	if (!PageUptodate(page)) {
 		struct bio *bio;
 
-		bio = erofs_grab_bio(sb, blkaddr, 1, sb, read_endio, nofail);
-		if (IS_ERR(bio)) {
-			DBG_BUGON(nofail);
-			err = PTR_ERR(bio);
-			goto err_out;
-		}
+		bio = erofs_grab_bio(sb, blkaddr, 1, sb, read_endio);
 
 		if (bio_add_page(bio, page, PAGE_SIZE, 0) != PAGE_SIZE) {
 			err = -EFAULT;
@@ -275,13 +270,7 @@ static inline struct bio *erofs_read_raw_page(struct bio *bio,
 		if (nblocks > BIO_MAX_PAGES)
 			nblocks = BIO_MAX_PAGES;
 
-		bio = erofs_grab_bio(sb, blknr, nblocks, sb,
-				     read_endio, false);
-		if (IS_ERR(bio)) {
-			err = PTR_ERR(bio);
-			bio = NULL;
-			goto err_out;
-		}
+		bio = erofs_grab_bio(sb, blknr, nblocks, sb, read_endio);
 	}
 
 	err = bio_add_page(bio, page, PAGE_SIZE, 0);
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 6bd82a82b11f..01749be24f3d 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -410,24 +410,9 @@ static inline int z_erofs_map_blocks_iter(struct inode *inode,
 static inline struct bio *erofs_grab_bio(struct super_block *sb,
 					 erofs_blk_t blkaddr,
 					 unsigned int nr_pages,
-					 void *bi_private, bio_end_io_t endio,
-					 bool nofail)
+					 void *bi_private, bio_end_io_t endio)
 {
-	const gfp_t gfp = GFP_NOIO;
-	struct bio *bio;
-
-	do {
-		if (nr_pages == 1) {
-			bio = bio_alloc(gfp | (nofail ? __GFP_NOFAIL : 0), 1);
-			if (!bio) {
-				DBG_BUGON(nofail);
-				return ERR_PTR(-ENOMEM);
-			}
-			break;
-		}
-		bio = bio_alloc(gfp, nr_pages);
-		nr_pages /= 2;
-	} while (!bio);
+	struct bio *bio = bio_alloc(GFP_NOIO, nr_pages);
 
 	bio->bi_end_io = endio;
 	bio_set_dev(bio, sb->s_bdev);
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index f06a2fad7af2..abe28565d6c0 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -1265,7 +1265,7 @@ static bool z_erofs_vle_submit_all(struct super_block *sb,
 		if (!bio) {
 			bio = erofs_grab_bio(sb, first_index + i,
 					     BIO_MAX_PAGES, bi_private,
-					     z_erofs_vle_read_endio, true);
+					     z_erofs_vle_read_endio);
 			++nr_bios;
 		}
 
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH 14/21] erofs: kill prio and nofail of erofs_get_meta_page()
  2019-09-01  5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang
                     ` (12 preceding siblings ...)
  2019-09-01  5:51   ` [PATCH 13/21] erofs: simplify erofs_grab_bio() since bio_alloc() never fail Gao Xiang
@ 2019-09-01  5:51   ` Gao Xiang
  2019-09-02 12:21     ` Christoph Hellwig
  2019-09-01  5:51   ` [PATCH 15/21] erofs: kill __submit_bio() Gao Xiang
                     ` (8 subsequent siblings)
  22 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-01  5:51 UTC (permalink / raw)
  To: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman
  Cc: linux-fsdevel, devel, linux-erofs, Chao Yu, Gao Xiang

From: Gao Xiang <gaoxiang25@huawei.com>

As Christoph pointed out [1],
"Why is there __erofs_get_meta_page with the two weird
booleans instead of a single erofs_get_meta_page that
gets and gfp_t for additional flags and an unsigned int
for additional bio op flags."

And since all callers can handle errors, let's kill
prio and nofail and erofs_get_inline_page() now.

[1] https://lore.kernel.org/lkml/20190830162812.GA10694@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/data.c     | 24 ++++++------------------
 fs/erofs/inode.c    |  2 +-
 fs/erofs/internal.h | 18 +-----------------
 fs/erofs/xattr.c    | 13 ++++++-------
 fs/erofs/zmap.c     |  4 ++--
 5 files changed, 16 insertions(+), 45 deletions(-)

diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index 621954d4fb09..837b07cd2761 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -38,25 +38,20 @@ static inline void read_endio(struct bio *bio)
 	bio_put(bio);
 }
 
-/* prio -- true is used for dir */
-struct page *__erofs_get_meta_page(struct super_block *sb,
-				   erofs_blk_t blkaddr, bool prio, bool nofail)
+struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr)
 {
 	struct inode *const bd_inode = sb->s_bdev->bd_inode;
 	struct address_space *const mapping = bd_inode->i_mapping;
 	/* prefer retrying in the allocator to blindly looping below */
-	const gfp_t gfp = mapping_gfp_constraint(mapping, ~__GFP_FS) |
-		(nofail ? __GFP_NOFAIL : 0);
-	unsigned int io_retries = nofail ? EROFS_IO_MAX_RETRIES_NOFAIL : 0;
+	const gfp_t gfp = mapping_gfp_constraint(mapping, ~__GFP_FS);
 	struct page *page;
 	int err;
 
 repeat:
 	page = find_or_create_page(mapping, blkaddr, gfp);
-	if (!page) {
-		DBG_BUGON(nofail);
+	if (!page)
 		return ERR_PTR(-ENOMEM);
-	}
+
 	DBG_BUGON(!PageLocked(page));
 
 	if (!PageUptodate(page)) {
@@ -69,14 +64,11 @@ struct page *__erofs_get_meta_page(struct super_block *sb,
 			goto err_out;
 		}
 
-		__submit_bio(bio, REQ_OP_READ,
-			     REQ_META | (prio ? REQ_PRIO : 0));
-
+		__submit_bio(bio, REQ_OP_READ, REQ_META);
 		lock_page(page);
 
 		/* this page has been truncated by others */
 		if (page->mapping != mapping) {
-unlock_repeat:
 			unlock_page(page);
 			put_page(page);
 			goto repeat;
@@ -84,10 +76,6 @@ struct page *__erofs_get_meta_page(struct super_block *sb,
 
 		/* more likely a read error */
 		if (!PageUptodate(page)) {
-			if (io_retries) {
-				--io_retries;
-				goto unlock_repeat;
-			}
 			err = -EIO;
 			goto err_out;
 		}
@@ -237,7 +225,7 @@ static inline struct bio *erofs_read_raw_page(struct bio *bio,
 
 			DBG_BUGON(map.m_plen > PAGE_SIZE);
 
-			ipage = erofs_get_meta_page(inode->i_sb, blknr, 0);
+			ipage = erofs_get_meta_page(inode->i_sb, blknr);
 
 			if (IS_ERR(ipage)) {
 				err = PTR_ERR(ipage);
diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index d501ceb62c29..19a574ee690b 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -163,7 +163,7 @@ static int fill_inode(struct inode *inode, int isdir)
 	debugln("%s, reading inode nid %llu at %u of blkaddr %u",
 		__func__, vi->nid, ofs, blkaddr);
 
-	page = erofs_get_meta_page(inode->i_sb, blkaddr, isdir);
+	page = erofs_get_meta_page(inode->i_sb, blkaddr);
 
 	if (IS_ERR(page)) {
 		errln("failed to get inode (nid: %llu) page, err %ld",
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 01749be24f3d..40d4dd47bb7a 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -258,8 +258,6 @@ static inline int erofs_wait_on_workgroup_freezed(struct erofs_workgroup *grp)
 #error erofs cannot be used in this platform
 #endif
 
-#define EROFS_IO_MAX_RETRIES_NOFAIL     5
-
 #define ROOT_NID(sb)		((sb)->root_nid)
 
 #define erofs_blknr(addr)       ((addr) / EROFS_BLKSIZ)
@@ -428,24 +426,10 @@ static inline void __submit_bio(struct bio *bio, unsigned int op,
 	submit_bio(bio);
 }
 
-struct page *__erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr,
-				   bool prio, bool nofail);
-
-static inline struct page *erofs_get_meta_page(struct super_block *sb,
-	erofs_blk_t blkaddr, bool prio)
-{
-	return __erofs_get_meta_page(sb, blkaddr, prio, false);
-}
+struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr);
 
 int erofs_map_blocks(struct inode *, struct erofs_map_blocks *, int);
 
-static inline struct page *erofs_get_inline_page(struct inode *inode,
-						 erofs_blk_t blkaddr)
-{
-	return erofs_get_meta_page(inode->i_sb, blkaddr,
-				   S_ISDIR(inode->i_mode));
-}
-
 /* inode.c */
 static inline unsigned long erofs_inode_hash(erofs_nid_t nid)
 {
diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c
index d5b7fe0bee45..dd445c81c41f 100644
--- a/fs/erofs/xattr.c
+++ b/fs/erofs/xattr.c
@@ -87,7 +87,7 @@ static int init_inode_xattrs(struct inode *inode)
 	it.blkaddr = erofs_blknr(iloc(sbi, vi->nid) + vi->inode_isize);
 	it.ofs = erofs_blkoff(iloc(sbi, vi->nid) + vi->inode_isize);
 
-	it.page = erofs_get_inline_page(inode, it.blkaddr);
+	it.page = erofs_get_meta_page(sb, it.blkaddr);
 	if (IS_ERR(it.page)) {
 		ret = PTR_ERR(it.page);
 		goto out_unlock;
@@ -117,8 +117,7 @@ static int init_inode_xattrs(struct inode *inode)
 			DBG_BUGON(it.ofs != EROFS_BLKSIZ);
 			xattr_iter_end(&it, atomic_map);
 
-			it.page = erofs_get_meta_page(sb, ++it.blkaddr,
-						      S_ISDIR(inode->i_mode));
+			it.page = erofs_get_meta_page(sb, ++it.blkaddr);
 			if (IS_ERR(it.page)) {
 				kfree(vi->xattr_shared_xattrs);
 				vi->xattr_shared_xattrs = NULL;
@@ -168,7 +167,7 @@ static inline int xattr_iter_fixup(struct xattr_iter *it)
 
 	it->blkaddr += erofs_blknr(it->ofs);
 
-	it->page = erofs_get_meta_page(it->sb, it->blkaddr, false);
+	it->page = erofs_get_meta_page(it->sb, it->blkaddr);
 	if (IS_ERR(it->page)) {
 		int err = PTR_ERR(it->page);
 
@@ -199,7 +198,7 @@ static int inline_xattr_iter_begin(struct xattr_iter *it,
 	it->blkaddr = erofs_blknr(iloc(sbi, vi->nid) + inline_xattr_ofs);
 	it->ofs = erofs_blkoff(iloc(sbi, vi->nid) + inline_xattr_ofs);
 
-	it->page = erofs_get_inline_page(inode, it->blkaddr);
+	it->page = erofs_get_meta_page(inode->i_sb, it->blkaddr);
 	if (IS_ERR(it->page))
 		return PTR_ERR(it->page);
 
@@ -401,7 +400,7 @@ static int shared_getxattr(struct inode *inode, struct getxattr_iter *it)
 			if (i)
 				xattr_iter_end(&it->it, true);
 
-			it->it.page = erofs_get_meta_page(sb, blkaddr, false);
+			it->it.page = erofs_get_meta_page(sb, blkaddr);
 			if (IS_ERR(it->it.page))
 				return PTR_ERR(it->it.page);
 
@@ -623,7 +622,7 @@ static int shared_listxattr(struct listxattr_iter *it)
 			if (i)
 				xattr_iter_end(&it->it, true);
 
-			it->it.page = erofs_get_meta_page(sb, blkaddr, false);
+			it->it.page = erofs_get_meta_page(sb, blkaddr);
 			if (IS_ERR(it->it.page))
 				return PTR_ERR(it->it.page);
 
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index c2dd778ebdd3..fbf6591f69a6 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -50,7 +50,7 @@ static int fill_inode_lazy(struct inode *inode)
 
 	pos = ALIGN(iloc(EROFS_SB(sb), vi->nid) + vi->inode_isize +
 		    vi->xattr_isize, 8);
-	page = erofs_get_meta_page(sb, erofs_blknr(pos), false);
+	page = erofs_get_meta_page(sb, erofs_blknr(pos));
 	if (IS_ERR(page)) {
 		err = PTR_ERR(page);
 		goto out_unlock;
@@ -127,7 +127,7 @@ static int z_erofs_reload_indexes(struct z_erofs_maprecorder *m,
 		put_page(mpage);
 	}
 
-	mpage = erofs_get_meta_page(sb, eblk, false);
+	mpage = erofs_get_meta_page(sb, eblk);
 	if (IS_ERR(mpage)) {
 		map->mpage = NULL;
 		return PTR_ERR(mpage);
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH 15/21] erofs: kill __submit_bio()
  2019-09-01  5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang
                     ` (13 preceding siblings ...)
  2019-09-01  5:51   ` [PATCH 14/21] erofs: kill prio and nofail of erofs_get_meta_page() Gao Xiang
@ 2019-09-01  5:51   ` Gao Xiang
  2019-09-01  5:51   ` [PATCH 16/21] erofs: kill magic underscores Gao Xiang
                     ` (7 subsequent siblings)
  22 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-01  5:51 UTC (permalink / raw)
  To: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman
  Cc: linux-fsdevel, devel, linux-erofs, Chao Yu, Gao Xiang

From: Gao Xiang <gaoxiang25@huawei.com>

As Christoph pointed out [1], "
Why is there __submit_bio which really just obsfucates
what is going on?  Also why is __submit_bio using
bio_set_op_attrs instead of opencode it as the comment
right next to it asks you to? "

Let's use submit_bio directly instead.

[1] https://lore.kernel.org/lkml/20190830162812.GA10694@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/data.c     | 15 ++++++++-------
 fs/erofs/internal.h |  9 ++-------
 fs/erofs/zdata.c    |  6 +++---
 3 files changed, 13 insertions(+), 17 deletions(-)

diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index 837b07cd2761..d3cd7a453648 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -57,14 +57,15 @@ struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr)
 	if (!PageUptodate(page)) {
 		struct bio *bio;
 
-		bio = erofs_grab_bio(sb, blkaddr, 1, sb, read_endio);
+		bio = erofs_grab_bio(sb, REQ_OP_READ | REQ_META,
+				     blkaddr, 1, sb, read_endio);
 
 		if (bio_add_page(bio, page, PAGE_SIZE, 0) != PAGE_SIZE) {
 			err = -EFAULT;
 			goto err_out;
 		}
 
-		__submit_bio(bio, REQ_OP_READ, REQ_META);
+		submit_bio(bio);
 		lock_page(page);
 
 		/* this page has been truncated by others */
@@ -188,7 +189,7 @@ static inline struct bio *erofs_read_raw_page(struct bio *bio,
 	    /* not continuous */
 	    *last_block + 1 != current_block) {
 submit_bio_retry:
-		__submit_bio(bio, REQ_OP_READ, 0);
+		submit_bio(bio);
 		bio = NULL;
 	}
 
@@ -258,7 +259,8 @@ static inline struct bio *erofs_read_raw_page(struct bio *bio,
 		if (nblocks > BIO_MAX_PAGES)
 			nblocks = BIO_MAX_PAGES;
 
-		bio = erofs_grab_bio(sb, blknr, nblocks, sb, read_endio);
+		bio = erofs_grab_bio(sb, REQ_OP_READ, blknr, nblocks,
+				     sb, read_endio);
 	}
 
 	err = bio_add_page(bio, page, PAGE_SIZE, 0);
@@ -289,8 +291,7 @@ static inline struct bio *erofs_read_raw_page(struct bio *bio,
 	/* if updated manually, continuous pages has a gap */
 	if (bio)
 submit_bio_out:
-		__submit_bio(bio, REQ_OP_READ, 0);
-
+		submit_bio(bio);
 	return err ? ERR_PTR(err) : NULL;
 }
 
@@ -354,7 +355,7 @@ static int erofs_raw_access_readpages(struct file *filp,
 
 	/* the rare case (end in gaps) */
 	if (bio)
-		__submit_bio(bio, REQ_OP_READ, 0);
+		submit_bio(bio);
 	return 0;
 }
 
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 40d4dd47bb7a..15545959af92 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -406,6 +406,7 @@ static inline int z_erofs_map_blocks_iter(struct inode *inode,
 
 /* data.c */
 static inline struct bio *erofs_grab_bio(struct super_block *sb,
+					 unsigned int bi_opf,
 					 erofs_blk_t blkaddr,
 					 unsigned int nr_pages,
 					 void *bi_private, bio_end_io_t endio)
@@ -416,16 +417,10 @@ static inline struct bio *erofs_grab_bio(struct super_block *sb,
 	bio_set_dev(bio, sb->s_bdev);
 	bio->bi_iter.bi_sector = (sector_t)blkaddr << LOG_SECTORS_PER_BLOCK;
 	bio->bi_private = bi_private;
+	bio->bi_opf = bi_opf;
 	return bio;
 }
 
-static inline void __submit_bio(struct bio *bio, unsigned int op,
-				unsigned int op_flags)
-{
-	bio_set_op_attrs(bio, op, op_flags);
-	submit_bio(bio);
-}
-
 struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr);
 
 int erofs_map_blocks(struct inode *, struct erofs_map_blocks *, int);
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index abe28565d6c0..ce1a0f2997a9 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -1258,12 +1258,12 @@ static bool z_erofs_vle_submit_all(struct super_block *sb,
 
 		if (bio && force_submit) {
 submit_bio_retry:
-			__submit_bio(bio, REQ_OP_READ, 0);
+			submit_bio(bio);
 			bio = NULL;
 		}
 
 		if (!bio) {
-			bio = erofs_grab_bio(sb, first_index + i,
+			bio = erofs_grab_bio(sb, REQ_OP_READ, first_index + i,
 					     BIO_MAX_PAGES, bi_private,
 					     z_erofs_vle_read_endio);
 			++nr_bios;
@@ -1286,7 +1286,7 @@ static bool z_erofs_vle_submit_all(struct super_block *sb,
 	} while (owned_head != Z_EROFS_PCLUSTER_TAIL);
 
 	if (bio)
-		__submit_bio(bio, REQ_OP_READ, 0);
+		submit_bio(bio);
 
 	if (postsubmit_is_all_bypassed(q, nr_bios, force_fg))
 		return true;
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH 16/21] erofs: kill magic underscores
  2019-09-01  5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang
                     ` (14 preceding siblings ...)
  2019-09-01  5:51   ` [PATCH 15/21] erofs: kill __submit_bio() Gao Xiang
@ 2019-09-01  5:51   ` Gao Xiang
  2019-09-02 12:26     ` Christoph Hellwig
  2019-09-01  5:51   ` [PATCH 17/21] erofs: use a switch statement when dealing with the file modes Gao Xiang
                     ` (6 subsequent siblings)
  22 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-01  5:51 UTC (permalink / raw)
  To: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman
  Cc: linux-fsdevel, devel, linux-erofs, Chao Yu, Gao Xiang

From: Gao Xiang <gaoxiang25@huawei.com>

As Christoph said [1], "
> +	vi->datamode = __inode_data_mapping(advise);

What is the deal with these magic underscores here and various
other similar helpers? "

Let avoid magic underscores now...
[1] https://lore.kernel.org/lkml/20190829102426.GE20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/inode.c    |  8 ++++----
 fs/erofs/internal.h | 14 ++++++--------
 2 files changed, 10 insertions(+), 12 deletions(-)

diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index 19a574ee690b..2ca4eda6e5bf 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -16,7 +16,7 @@ static int read_inode(struct inode *inode, void *data)
 	const unsigned int advise = le16_to_cpu(v1->i_advise);
 	erofs_blk_t nblks = 0;
 
-	vi->datamode = __inode_data_mapping(advise);
+	vi->datamode = erofs_inode_data_mapping(advise);
 
 	if (vi->datamode >= EROFS_INODE_LAYOUT_MAX) {
 		errln("unsupported data mapping %u of nid %llu",
@@ -25,7 +25,7 @@ static int read_inode(struct inode *inode, void *data)
 		return -EOPNOTSUPP;
 	}
 
-	if (__inode_version(advise) == EROFS_INODE_LAYOUT_V2) {
+	if (erofs_inode_version(advise) == EROFS_INODE_LAYOUT_V2) {
 		struct erofs_inode_v2 *v2 = data;
 
 		vi->inode_isize = sizeof(struct erofs_inode_v2);
@@ -58,7 +58,7 @@ static int read_inode(struct inode *inode, void *data)
 		/* total blocks for compressed files */
 		if (erofs_inode_is_data_compressed(vi->datamode))
 			nblks = le32_to_cpu(v2->i_u.compressed_blocks);
-	} else if (__inode_version(advise) == EROFS_INODE_LAYOUT_V1) {
+	} else if (erofs_inode_version(advise) == EROFS_INODE_LAYOUT_V1) {
 		struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
 
 		vi->inode_isize = sizeof(struct erofs_inode_v1);
@@ -91,7 +91,7 @@ static int read_inode(struct inode *inode, void *data)
 			nblks = le32_to_cpu(v1->i_u.compressed_blocks);
 	} else {
 		errln("unsupported on-disk inode version %u of nid %llu",
-		      __inode_version(advise), vi->nid);
+		      erofs_inode_version(advise), vi->nid);
 		DBG_BUGON(1);
 		return -EOPNOTSUPP;
 	}
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 15545959af92..4a35a31fd454 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -308,16 +308,14 @@ struct erofs_inode {
 #define EROFS_I(ptr)	\
 	container_of(ptr, struct erofs_inode, vfs_inode)
 
-#define __inode_advise(x, bit, bits) \
-	(((x) >> (bit)) & ((1 << (bits)) - 1))
+#define erofs_bitrange(x, bit, bits) (((x) >> (bit)) & ((1 << (bits)) - 1))
 
-#define __inode_version(advise)	\
-	__inode_advise(advise, EROFS_I_VERSION_BIT,	\
-		EROFS_I_VERSION_BITS)
+#define erofs_inode_version(advise)	\
+	erofs_bitrange(advise, EROFS_I_VERSION_BIT, EROFS_I_VERSION_BITS)
 
-#define __inode_data_mapping(advise)	\
-	__inode_advise(advise, EROFS_I_DATA_MAPPING_BIT,\
-		EROFS_I_DATA_MAPPING_BITS)
+#define erofs_inode_data_mapping(advise)	\
+	erofs_bitrange(advise, EROFS_I_DATA_MAPPING_BIT, \
+		       EROFS_I_DATA_MAPPING_BITS)
 
 static inline unsigned long inode_datablocks(struct inode *inode)
 {
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH 17/21] erofs: use a switch statement when dealing with the file modes
  2019-09-01  5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang
                     ` (15 preceding siblings ...)
  2019-09-01  5:51   ` [PATCH 16/21] erofs: kill magic underscores Gao Xiang
@ 2019-09-01  5:51   ` Gao Xiang
  2019-09-02 12:27     ` Christoph Hellwig
  2019-09-01  5:51   ` [PATCH 18/21] erofs: add "erofs_" prefix for common and short functions Gao Xiang
                     ` (5 subsequent siblings)
  22 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-01  5:51 UTC (permalink / raw)
  To: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman
  Cc: linux-fsdevel, devel, linux-erofs, Chao Yu, Gao Xiang

From: Gao Xiang <gaoxiang25@huawei.com>

As Christoph suggested [1], "
Please use a switch statement when dealing with the file modes
to make everything easier to read."

[1] https://lore.kernel.org/r/20190829102503.GF20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/inode.c | 38 ++++++++++++++++++++++++++------------
 1 file changed, 26 insertions(+), 12 deletions(-)

diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index 2ca4eda6e5bf..6e2486cc3cd4 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -32,17 +32,24 @@ static int read_inode(struct inode *inode, void *data)
 		vi->xattr_isize = erofs_xattr_ibody_size(v2->i_xattr_icount);
 
 		inode->i_mode = le16_to_cpu(v2->i_mode);
-		if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
-		    S_ISLNK(inode->i_mode))
+		switch (inode->i_mode & S_IFMT) {
+		case S_IFREG:
+		case S_IFDIR:
+		case S_IFLNK:
 			vi->raw_blkaddr = le32_to_cpu(v2->i_u.raw_blkaddr);
-		else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
+			break;
+		case S_IFCHR:
+		case S_IFBLK:
 			inode->i_rdev =
 				new_decode_dev(le32_to_cpu(v2->i_u.rdev));
-		else if (S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode))
+			break;
+		case S_IFIFO:
+		case S_IFSOCK:
 			inode->i_rdev = 0;
-		else
+			break;
+		default:
 			goto bogusimode;
-
+		}
 		i_uid_write(inode, le32_to_cpu(v2->i_uid));
 		i_gid_write(inode, le32_to_cpu(v2->i_gid));
 		set_nlink(inode, le32_to_cpu(v2->i_nlink));
@@ -65,17 +72,24 @@ static int read_inode(struct inode *inode, void *data)
 		vi->xattr_isize = erofs_xattr_ibody_size(v1->i_xattr_icount);
 
 		inode->i_mode = le16_to_cpu(v1->i_mode);
-		if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
-		    S_ISLNK(inode->i_mode))
+		switch (inode->i_mode & S_IFMT) {
+		case S_IFREG:
+		case S_IFDIR:
+		case S_IFLNK:
 			vi->raw_blkaddr = le32_to_cpu(v1->i_u.raw_blkaddr);
-		else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
+			break;
+		case S_IFCHR:
+		case S_IFBLK:
 			inode->i_rdev =
 				new_decode_dev(le32_to_cpu(v1->i_u.rdev));
-		else if (S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode))
+			break;
+		case S_IFIFO:
+		case S_IFSOCK:
 			inode->i_rdev = 0;
-		else
+			break;
+		default:
 			goto bogusimode;
-
+		}
 		i_uid_write(inode, le16_to_cpu(v1->i_uid));
 		i_gid_write(inode, le16_to_cpu(v1->i_gid));
 		set_nlink(inode, le16_to_cpu(v1->i_nlink));
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH 18/21] erofs: add "erofs_" prefix for common and short functions
  2019-09-01  5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang
                     ` (16 preceding siblings ...)
  2019-09-01  5:51   ` [PATCH 17/21] erofs: use a switch statement when dealing with the file modes Gao Xiang
@ 2019-09-01  5:51   ` Gao Xiang
  2019-09-02 12:28     ` Christoph Hellwig
  2019-09-01  5:51   ` [PATCH 19/21] erofs: kill all erofs specific fault injection Gao Xiang
                     ` (4 subsequent siblings)
  22 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-01  5:51 UTC (permalink / raw)
  To: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman
  Cc: linux-fsdevel, devel, linux-erofs, Chao Yu, Gao Xiang

From: Gao Xiang <gaoxiang25@huawei.com>

Add erofs_ prefix to free_inode, alloc_inode, ...

Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/data.c         |  6 +++---
 fs/erofs/decompressor.c | 22 +++++++++++-----------
 fs/erofs/inode.c        |  8 ++++----
 fs/erofs/namei.c        | 10 +++++-----
 fs/erofs/super.c        | 26 +++++++++++++-------------
 fs/erofs/zdata.c        | 19 ++++++++++---------
 6 files changed, 46 insertions(+), 45 deletions(-)

diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index d3cd7a453648..e8325eaa0fd8 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -9,7 +9,7 @@
 
 #include <trace/events/erofs.h>
 
-static inline void read_endio(struct bio *bio)
+static void erofs_readendio(struct bio *bio)
 {
 	struct super_block *const sb = bio->bi_private;
 	struct bio_vec *bvec;
@@ -58,7 +58,7 @@ struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr)
 		struct bio *bio;
 
 		bio = erofs_grab_bio(sb, REQ_OP_READ | REQ_META,
-				     blkaddr, 1, sb, read_endio);
+				     blkaddr, 1, sb, erofs_readendio);
 
 		if (bio_add_page(bio, page, PAGE_SIZE, 0) != PAGE_SIZE) {
 			err = -EFAULT;
@@ -260,7 +260,7 @@ static inline struct bio *erofs_read_raw_page(struct bio *bio,
 			nblocks = BIO_MAX_PAGES;
 
 		bio = erofs_grab_bio(sb, REQ_OP_READ, blknr, nblocks,
-				     sb, read_endio);
+				     sb, erofs_readendio);
 	}
 
 	err = bio_add_page(bio, page, PAGE_SIZE, 0);
diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index df349888f911..bb2944c96c89 100644
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -32,8 +32,8 @@ static bool use_vmap;
 module_param(use_vmap, bool, 0444);
 MODULE_PARM_DESC(use_vmap, "Use vmap() instead of vm_map_ram() (default 0)");
 
-static int lz4_prepare_destpages(struct z_erofs_decompress_req *rq,
-				 struct list_head *pagepool)
+static int z_erofs_lz4_prepare_destpages(struct z_erofs_decompress_req *rq,
+					 struct list_head *pagepool)
 {
 	const unsigned int nr =
 		PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
@@ -114,7 +114,7 @@ static void *generic_copy_inplace_data(struct z_erofs_decompress_req *rq,
 	return tmp;
 }
 
-static int lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out)
+static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out)
 {
 	unsigned int inputmargin, inlen;
 	u8 *src;
@@ -187,8 +187,8 @@ static struct z_erofs_decompressor decompressors[] = {
 		.name = "shifted"
 	},
 	[Z_EROFS_COMPRESSION_LZ4] = {
-		.prepare_destpages = lz4_prepare_destpages,
-		.decompress = lz4_decompress,
+		.prepare_destpages = z_erofs_lz4_prepare_destpages,
+		.decompress = z_erofs_lz4_decompress,
 		.name = "lz4"
 	},
 };
@@ -246,8 +246,8 @@ static void erofs_vunmap(const void *mem, unsigned int count)
 		vunmap(mem);
 }
 
-static int decompress_generic(struct z_erofs_decompress_req *rq,
-			      struct list_head *pagepool)
+static int z_erofs_decompress_generic(struct z_erofs_decompress_req *rq,
+				      struct list_head *pagepool)
 {
 	const unsigned int nrpages_out =
 		PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
@@ -307,8 +307,8 @@ static int decompress_generic(struct z_erofs_decompress_req *rq,
 	return ret;
 }
 
-static int shifted_decompress(const struct z_erofs_decompress_req *rq,
-			      struct list_head *pagepool)
+static int z_erofs_shifted_transform(const struct z_erofs_decompress_req *rq,
+				     struct list_head *pagepool)
 {
 	const unsigned int nrpages_out =
 		PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
@@ -352,7 +352,7 @@ int z_erofs_decompress(struct z_erofs_decompress_req *rq,
 		       struct list_head *pagepool)
 {
 	if (rq->alg == Z_EROFS_COMPRESSION_SHIFTED)
-		return shifted_decompress(rq, pagepool);
-	return decompress_generic(rq, pagepool);
+		return z_erofs_shifted_transform(rq, pagepool);
+	return z_erofs_decompress_generic(rq, pagepool);
 }
 
diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index 6e2486cc3cd4..7da5a41f82e3 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -9,7 +9,7 @@
 #include <trace/events/erofs.h>
 
 /* no locking */
-static int read_inode(struct inode *inode, void *data)
+static int erofs_read_inode(struct inode *inode, void *data)
 {
 	struct erofs_inode *vi = EROFS_I(inode);
 	struct erofs_inode_v1 *v1 = data;
@@ -158,7 +158,7 @@ static int erofs_fill_symlink(struct inode *inode, void *data,
 	return 0;
 }
 
-static int fill_inode(struct inode *inode, int isdir)
+static int erofs_fill_inode(struct inode *inode, int isdir)
 {
 	struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
 	struct erofs_inode *vi = EROFS_I(inode);
@@ -188,7 +188,7 @@ static int fill_inode(struct inode *inode, int isdir)
 	DBG_BUGON(!PageUptodate(page));
 	data = page_address(page);
 
-	err = read_inode(inode, data + ofs);
+	err = erofs_read_inode(inode, data + ofs);
 	if (!err) {
 		/* setup the new inode */
 		switch (inode->i_mode & S_IFMT) {
@@ -281,7 +281,7 @@ struct inode *erofs_iget(struct super_block *sb,
 
 		vi->nid = nid;
 
-		err = fill_inode(inode, isdir);
+		err = erofs_fill_inode(inode, isdir);
 		if (!err)
 			unlock_new_inode(inode);
 		else {
diff --git a/fs/erofs/namei.c b/fs/erofs/namei.c
index a6b6a4ab1403..108033be8af5 100644
--- a/fs/erofs/namei.c
+++ b/fs/erofs/namei.c
@@ -14,9 +14,9 @@ struct erofs_qstr {
 };
 
 /* based on the end of qn is accurate and it must have the trailing '\0' */
-static inline int dirnamecmp(const struct erofs_qstr *qn,
-			     const struct erofs_qstr *qd,
-			     unsigned int *matched)
+static inline int erofs_dirnamecmp(const struct erofs_qstr *qn,
+				   const struct erofs_qstr *qd,
+				   unsigned int *matched)
 {
 	unsigned int i = *matched;
 
@@ -71,7 +71,7 @@ static struct erofs_dirent *find_target_dirent(struct erofs_qstr *name,
 		};
 
 		/* string comparison without already matched prefix */
-		int ret = dirnamecmp(name, &dname, &matched);
+		int ret = erofs_dirnamecmp(name, &dname, &matched);
 
 		if (!ret) {
 			return de + mid;
@@ -134,7 +134,7 @@ static struct page *find_target_block_classic(struct inode *dir,
 							  EROFS_BLKSIZ);
 
 			/* string comparison without already matched prefix */
-			diff = dirnamecmp(name, &dname, &matched);
+			diff = erofs_dirnamecmp(name, &dname, &matched);
 			kunmap_atomic(de);
 
 			if (!diff) {
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index b4bf72755300..7bdd9f47c4ac 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -16,12 +16,12 @@
 
 static struct kmem_cache *erofs_inode_cachep __read_mostly;
 
-static void init_once(void *ptr)
+static void erofs_inode_init_once(void *ptr)
 {
 	inode_init_once(&((struct erofs_inode *)ptr)->vfs_inode);
 }
 
-static struct inode *alloc_inode(struct super_block *sb)
+static struct inode *erofs_alloc_inode(struct super_block *sb)
 {
 	struct erofs_inode *vi =
 		kmem_cache_alloc(erofs_inode_cachep, GFP_KERNEL);
@@ -34,7 +34,7 @@ static struct inode *alloc_inode(struct super_block *sb)
 	return &vi->vfs_inode;
 }
 
-static void free_inode(struct inode *inode)
+static void erofs_free_inode(struct inode *inode)
 {
 	struct erofs_inode *vi = EROFS_I(inode);
 
@@ -62,7 +62,7 @@ static bool check_layout_compatibility(struct super_block *sb,
 	return true;
 }
 
-static int superblock_read(struct super_block *sb)
+static int erofs_read_superblock(struct super_block *sb)
 {
 	struct erofs_sb_info *sbi;
 	struct buffer_head *bh;
@@ -217,7 +217,7 @@ static int erofs_build_cache_strategy(struct erofs_sb_info *sbi,
 #endif
 
 /* set up default EROFS parameters */
-static void default_options(struct erofs_sb_info *sbi)
+static void erofs_default_options(struct erofs_sb_info *sbi)
 {
 #ifdef CONFIG_EROFS_FS_ZIP
 	sbi->cache_strategy = EROFS_ZIP_CACHE_READAROUND;
@@ -251,7 +251,7 @@ static match_table_t erofs_tokens = {
 	{Opt_err, NULL}
 };
 
-static int parse_options(struct super_block *sb, char *options)
+static int erofs_parse_options(struct super_block *sb, char *options)
 {
 	substring_t args[MAX_OPT_ARGS];
 	char *p;
@@ -395,7 +395,7 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
 		return -ENOMEM;
 
 	sb->s_fs_info = sbi;
-	err = superblock_read(sb);
+	err = erofs_read_superblock(sb);
 	if (err)
 		return err;
 
@@ -409,9 +409,9 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
 	sb->s_xattr = erofs_xattr_handlers;
 #endif
 	/* set erofs default mount options */
-	default_options(sbi);
+	erofs_default_options(sbi);
 
-	err = parse_options(sb, data);
+	err = erofs_parse_options(sb, data);
 	if (err)
 		return err;
 
@@ -511,7 +511,7 @@ static int __init erofs_module_init(void)
 	erofs_inode_cachep = kmem_cache_create("erofs_inode",
 					       sizeof(struct erofs_inode), 0,
 					       SLAB_RECLAIM_ACCOUNT,
-					       init_once);
+					       erofs_inode_init_once);
 	if (!erofs_inode_cachep) {
 		err = -ENOMEM;
 		goto icache_err;
@@ -618,7 +618,7 @@ static int erofs_remount(struct super_block *sb, int *flags, char *data)
 	int err;
 
 	DBG_BUGON(!sb_rdonly(sb));
-	err = parse_options(sb, data);
+	err = erofs_parse_options(sb, data);
 	if (err)
 		goto out;
 
@@ -638,8 +638,8 @@ static int erofs_remount(struct super_block *sb, int *flags, char *data)
 
 const struct super_operations erofs_sops = {
 	.put_super = erofs_put_super,
-	.alloc_inode = alloc_inode,
-	.free_inode = free_inode,
+	.alloc_inode = erofs_alloc_inode,
+	.free_inode = erofs_free_inode,
 	.statfs = erofs_statfs,
 	.show_options = erofs_show_options,
 	.remount_fs = erofs_remount,
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index ce1a0f2997a9..3af040c608f1 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -40,7 +40,7 @@ void z_erofs_exit_zip_subsystem(void)
 	kmem_cache_destroy(pcluster_cachep);
 }
 
-static inline int init_unzip_workqueue(void)
+static inline int z_erofs_init_workqueue(void)
 {
 	const unsigned int onlinecpus = num_possible_cpus();
 	const unsigned int flags = WQ_UNBOUND | WQ_HIGHPRI | WQ_CPU_INTENSIVE;
@@ -54,7 +54,7 @@ static inline int init_unzip_workqueue(void)
 	return z_erofs_workqueue ? 0 : -ENOMEM;
 }
 
-static void init_once(void *ptr)
+static void z_erofs_pcluster_init_once(void *ptr)
 {
 	struct z_erofs_pcluster *pcl = ptr;
 	struct z_erofs_collection *cl = z_erofs_primarycollection(pcl);
@@ -67,7 +67,7 @@ static void init_once(void *ptr)
 		pcl->compressed_pages[i] = NULL;
 }
 
-static void init_always(struct z_erofs_pcluster *pcl)
+static void z_erofs_pcluster_init_always(struct z_erofs_pcluster *pcl)
 {
 	struct z_erofs_collection *cl = z_erofs_primarycollection(pcl);
 
@@ -81,9 +81,10 @@ int __init z_erofs_init_zip_subsystem(void)
 {
 	pcluster_cachep = kmem_cache_create("erofs_compress",
 					    Z_EROFS_WORKGROUP_SIZE, 0,
-					    SLAB_RECLAIM_ACCOUNT, init_once);
+					    SLAB_RECLAIM_ACCOUNT,
+					    z_erofs_pcluster_init_once);
 	if (pcluster_cachep) {
-		if (!init_unzip_workqueue())
+		if (!z_erofs_init_workqueue())
 			return 0;
 
 		kmem_cache_destroy(pcluster_cachep);
@@ -272,8 +273,8 @@ int erofs_try_to_free_cached_page(struct address_space *mapping,
 }
 
 /* page_type must be Z_EROFS_PAGE_TYPE_EXCLUSIVE */
-static inline bool try_inplace_io(struct z_erofs_collector *clt,
-				  struct page *page)
+static inline bool z_erofs_try_inplace_io(struct z_erofs_collector *clt,
+					  struct page *page)
 {
 	struct z_erofs_pcluster *const pcl = clt->pcl;
 	const unsigned int clusterpages = BIT(pcl->clusterbits);
@@ -296,7 +297,7 @@ static int z_erofs_attach_page(struct z_erofs_collector *clt,
 	/* give priority for inplaceio */
 	if (clt->mode >= COLLECT_PRIMARY &&
 	    type == Z_EROFS_PAGE_TYPE_EXCLUSIVE &&
-	    try_inplace_io(clt, page))
+	    z_erofs_try_inplace_io(clt, page))
 		return 0;
 
 	ret = z_erofs_pagevec_enqueue(&clt->vector,
@@ -409,7 +410,7 @@ static struct z_erofs_collection *clregister(struct z_erofs_collector *clt,
 	if (!pcl)
 		return ERR_PTR(-ENOMEM);
 
-	init_always(pcl);
+	z_erofs_pcluster_init_always(pcl);
 	pcl->obj.index = map->m_pa >> PAGE_SHIFT;
 
 	pcl->length = (map->m_llen << Z_EROFS_PCLUSTER_LENGTH_BIT) |
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH 19/21] erofs: kill all erofs specific fault injection
  2019-09-01  5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang
                     ` (17 preceding siblings ...)
  2019-09-01  5:51   ` [PATCH 18/21] erofs: add "erofs_" prefix for common and short functions Gao Xiang
@ 2019-09-01  5:51   ` Gao Xiang
  2019-09-02 12:28     ` Christoph Hellwig
  2019-09-01  5:51   ` [PATCH 20/21] erofs: kill use_vmap module parameter Gao Xiang
                     ` (3 subsequent siblings)
  22 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-01  5:51 UTC (permalink / raw)
  To: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman
  Cc: linux-fsdevel, devel, linux-erofs, Chao Yu, Gao Xiang

From: Gao Xiang <gaoxiang25@huawei.com>

As Christoph suggested [1], "Please just use plain kmalloc
everywhere and let the normal kernel error injection code
take care of injeting any errors."

[1] https://lore.kernel.org/r/20190829102426.GE20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 Documentation/filesystems/erofs.txt |  5 ---
 fs/erofs/Kconfig                    |  7 ---
 fs/erofs/data.c                     |  6 ---
 fs/erofs/inode.c                    |  3 +-
 fs/erofs/internal.h                 | 65 ---------------------------
 fs/erofs/super.c                    | 70 -----------------------------
 fs/erofs/zdata.c                    |  8 +---
 7 files changed, 2 insertions(+), 162 deletions(-)

diff --git a/Documentation/filesystems/erofs.txt b/Documentation/filesystems/erofs.txt
index 38aa9126ec98..c3b5f603b2b6 100644
--- a/Documentation/filesystems/erofs.txt
+++ b/Documentation/filesystems/erofs.txt
@@ -52,11 +52,6 @@ linux-erofs mailing list:
 Mount options
 =============
 
-fault_injection=%d     Enable fault injection in all supported types with
-                       specified injection rate. Supported injection type:
-                       Type_Name                Type_Value
-                       FAULT_KMALLOC            0x000000001
-                       FAULT_READ_IO            0x000000002
 (no)user_xattr         Setup Extended User Attributes. Note: xattr is enabled
                        by default if CONFIG_EROFS_FS_XATTR is selected.
 (no)acl                Setup POSIX Access Control List. Note: acl is enabled
diff --git a/fs/erofs/Kconfig b/fs/erofs/Kconfig
index 16316d1adca3..9d634d3a1845 100644
--- a/fs/erofs/Kconfig
+++ b/fs/erofs/Kconfig
@@ -27,13 +27,6 @@ config EROFS_FS_DEBUG
 
 	  For daily use, say N.
 
-config EROFS_FAULT_INJECTION
-	bool "EROFS fault injection facility"
-	depends on EROFS_FS
-	help
-	  Test EROFS to inject faults such as ENOMEM, EIO, and so on.
-	  If unsure, say N.
-
 config EROFS_FS_XATTR
 	bool "EROFS extended attributes"
 	depends on EROFS_FS
diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index e8325eaa0fd8..a2a5ea945482 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -11,16 +11,10 @@
 
 static void erofs_readendio(struct bio *bio)
 {
-	struct super_block *const sb = bio->bi_private;
 	struct bio_vec *bvec;
 	blk_status_t err = bio->bi_status;
 	struct bvec_iter_all iter_all;
 
-	if (time_to_inject(EROFS_SB(sb), FAULT_READ_IO)) {
-		erofs_show_injection_info(FAULT_READ_IO);
-		err = BLK_STS_IOERR;
-	}
-
 	bio_for_each_segment_all(bvec, bio, iter_all) {
 		struct page *page = bvec->bv_page;
 
diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index 7da5a41f82e3..fcc16d2d10cb 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -127,11 +127,10 @@ static int erofs_fill_symlink(struct inode *inode, void *data,
 			      unsigned int m_pofs)
 {
 	struct erofs_inode *vi = EROFS_I(inode);
-	struct erofs_sb_info *sbi = EROFS_I_SB(inode);
 
 	/* if it can be handled with fast symlink scheme */
 	if (is_inode_flat_inline(inode) && inode->i_size < PAGE_SIZE) {
-		char *lnk = erofs_kmalloc(sbi, inode->i_size + 1, GFP_KERNEL);
+		char *lnk = kmalloc(inode->i_size + 1, GFP_KERNEL);
 
 		if (!lnk)
 			return -ENOMEM;
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 4a35a31fd454..f5fb5ba52fe2 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -32,23 +32,6 @@
 #define DBG_BUGON(x)            ((void)(x))
 #endif	/* !CONFIG_EROFS_FS_DEBUG */
 
-enum {
-	FAULT_KMALLOC,
-	FAULT_READ_IO,
-	FAULT_MAX,
-};
-
-#ifdef CONFIG_EROFS_FAULT_INJECTION
-extern const char *erofs_fault_name[FAULT_MAX];
-#define IS_FAULT_SET(fi, type) ((fi)->inject_type & (1 << (type)))
-
-struct erofs_fault_info {
-	atomic_t inject_ops;
-	unsigned int inject_rate;
-	unsigned int inject_type;
-};
-#endif	/* CONFIG_EROFS_FAULT_INJECTION */
-
 /* EROFS_SUPER_MAGIC_V1 to represent the whole file system */
 #define EROFS_SUPER_MAGIC   EROFS_SUPER_MAGIC_V1
 
@@ -99,62 +82,14 @@ struct erofs_sb_info {
 	u32 requirements;
 
 	unsigned int mount_opt;
-
-#ifdef CONFIG_EROFS_FAULT_INJECTION
-	struct erofs_fault_info fault_info;	/* For fault injection */
-#endif
 };
 
-#ifdef CONFIG_EROFS_FAULT_INJECTION
-#define erofs_show_injection_info(type)					\
-	infoln("inject %s in %s of %pS", erofs_fault_name[type],        \
-		__func__, __builtin_return_address(0))
-
-static inline bool time_to_inject(struct erofs_sb_info *sbi, int type)
-{
-	struct erofs_fault_info *ffi = &sbi->fault_info;
-
-	if (!ffi->inject_rate)
-		return false;
-
-	if (!IS_FAULT_SET(ffi, type))
-		return false;
-
-	atomic_inc(&ffi->inject_ops);
-	if (atomic_read(&ffi->inject_ops) >= ffi->inject_rate) {
-		atomic_set(&ffi->inject_ops, 0);
-		return true;
-	}
-	return false;
-}
-#else
-static inline bool time_to_inject(struct erofs_sb_info *sbi, int type)
-{
-	return false;
-}
-
-static inline void erofs_show_injection_info(int type)
-{
-}
-#endif	/* !CONFIG_EROFS_FAULT_INJECTION */
-
-static inline void *erofs_kmalloc(struct erofs_sb_info *sbi,
-					size_t size, gfp_t flags)
-{
-	if (time_to_inject(sbi, FAULT_KMALLOC)) {
-		erofs_show_injection_info(FAULT_KMALLOC);
-		return NULL;
-	}
-	return kmalloc(size, flags);
-}
-
 #define EROFS_SB(sb) ((struct erofs_sb_info *)(sb)->s_fs_info)
 #define EROFS_I_SB(inode) ((struct erofs_sb_info *)(inode)->i_sb->s_fs_info)
 
 /* Mount flags set via mount options or defaults */
 #define EROFS_MOUNT_XATTR_USER		0x00000010
 #define EROFS_MOUNT_POSIX_ACL		0x00000020
-#define EROFS_MOUNT_FAULT_INJECTION	0x00000040
 
 #define clear_opt(sbi, option)	((sbi)->mount_opt &= ~EROFS_MOUNT_##option)
 #define set_opt(sbi, option)	((sbi)->mount_opt |= EROFS_MOUNT_##option)
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 7bdd9f47c4ac..356025d07d04 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -125,63 +125,6 @@ static int erofs_read_superblock(struct super_block *sb)
 	return ret;
 }
 
-#ifdef CONFIG_EROFS_FAULT_INJECTION
-const char *erofs_fault_name[FAULT_MAX] = {
-	[FAULT_KMALLOC]		= "kmalloc",
-	[FAULT_READ_IO]		= "read IO error",
-};
-
-static void __erofs_build_fault_attr(struct erofs_sb_info *sbi,
-				     unsigned int rate)
-{
-	struct erofs_fault_info *ffi = &sbi->fault_info;
-
-	if (rate) {
-		atomic_set(&ffi->inject_ops, 0);
-		ffi->inject_rate = rate;
-		ffi->inject_type = (1 << FAULT_MAX) - 1;
-	} else {
-		memset(ffi, 0, sizeof(struct erofs_fault_info));
-	}
-
-	set_opt(sbi, FAULT_INJECTION);
-}
-
-static int erofs_build_fault_attr(struct erofs_sb_info *sbi,
-				  substring_t *args)
-{
-	int rate = 0;
-
-	if (args->from && match_int(args, &rate))
-		return -EINVAL;
-
-	__erofs_build_fault_attr(sbi, rate);
-	return 0;
-}
-
-static unsigned int erofs_get_fault_rate(struct erofs_sb_info *sbi)
-{
-	return sbi->fault_info.inject_rate;
-}
-#else
-static void __erofs_build_fault_attr(struct erofs_sb_info *sbi,
-				     unsigned int rate)
-{
-}
-
-static int erofs_build_fault_attr(struct erofs_sb_info *sbi,
-				  substring_t *args)
-{
-	infoln("fault_injection options not supported");
-	return 0;
-}
-
-static unsigned int erofs_get_fault_rate(struct erofs_sb_info *sbi)
-{
-	return 0;
-}
-#endif
-
 #ifdef CONFIG_EROFS_FS_ZIP
 static int erofs_build_cache_strategy(struct erofs_sb_info *sbi,
 				      substring_t *args)
@@ -236,7 +179,6 @@ enum {
 	Opt_nouser_xattr,
 	Opt_acl,
 	Opt_noacl,
-	Opt_fault_injection,
 	Opt_cache_strategy,
 	Opt_err
 };
@@ -246,7 +188,6 @@ static match_table_t erofs_tokens = {
 	{Opt_nouser_xattr, "nouser_xattr"},
 	{Opt_acl, "acl"},
 	{Opt_noacl, "noacl"},
-	{Opt_fault_injection, "fault_injection=%u"},
 	{Opt_cache_strategy, "cache_strategy=%s"},
 	{Opt_err, NULL}
 };
@@ -300,11 +241,6 @@ static int erofs_parse_options(struct super_block *sb, char *options)
 			infoln("noacl options not supported");
 			break;
 #endif
-		case Opt_fault_injection:
-			err = erofs_build_fault_attr(EROFS_SB(sb), args);
-			if (err)
-				return err;
-			break;
 		case Opt_cache_strategy:
 			err = erofs_build_cache_strategy(EROFS_SB(sb), args);
 			if (err)
@@ -592,9 +528,6 @@ static int erofs_show_options(struct seq_file *seq, struct dentry *root)
 	else
 		seq_puts(seq, ",noacl");
 #endif
-	if (test_opt(sbi, FAULT_INJECTION))
-		seq_printf(seq, ",fault_injection=%u",
-			   erofs_get_fault_rate(sbi));
 #ifdef CONFIG_EROFS_FS_ZIP
 	if (sbi->cache_strategy == EROFS_ZIP_CACHE_DISABLED) {
 		seq_puts(seq, ",cache_strategy=disabled");
@@ -614,7 +547,6 @@ static int erofs_remount(struct super_block *sb, int *flags, char *data)
 {
 	struct erofs_sb_info *sbi = EROFS_SB(sb);
 	unsigned int org_mnt_opt = sbi->mount_opt;
-	unsigned int org_inject_rate = erofs_get_fault_rate(sbi);
 	int err;
 
 	DBG_BUGON(!sb_rdonly(sb));
@@ -630,9 +562,7 @@ static int erofs_remount(struct super_block *sb, int *flags, char *data)
 	*flags |= SB_RDONLY;
 	return 0;
 out:
-	__erofs_build_fault_attr(sbi, org_inject_rate);
 	sbi->mount_opt = org_mnt_opt;
-
 	return err;
 }
 
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index 3af040c608f1..f772f07c57ed 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -724,15 +724,9 @@ static inline void z_erofs_vle_read_endio(struct bio *bio)
 		DBG_BUGON(PageUptodate(page));
 		DBG_BUGON(!page->mapping);
 
-		if (!sbi && !z_erofs_page_is_staging(page)) {
+		if (!sbi && !z_erofs_page_is_staging(page))
 			sbi = EROFS_SB(page->mapping->host->i_sb);
 
-			if (time_to_inject(sbi, FAULT_READ_IO)) {
-				erofs_show_injection_info(FAULT_READ_IO);
-				err = BLK_STS_IOERR;
-			}
-		}
-
 		/* sbi should already be gotten if the page is managed */
 		if (sbi)
 			cachemngd = erofs_page_is_managed(sbi, page);
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH 20/21] erofs: kill use_vmap module parameter
  2019-09-01  5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang
                     ` (18 preceding siblings ...)
  2019-09-01  5:51   ` [PATCH 19/21] erofs: kill all erofs specific fault injection Gao Xiang
@ 2019-09-01  5:51   ` Gao Xiang
  2019-09-02 12:31     ` Christoph Hellwig
  2019-09-01  5:51   ` [PATCH 21/21] erofs: save one level of indentation Gao Xiang
                     ` (2 subsequent siblings)
  22 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-01  5:51 UTC (permalink / raw)
  To: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman
  Cc: linux-fsdevel, devel, linux-erofs, Chao Yu, Gao Xiang

From: Gao Xiang <gaoxiang25@huawei.com>

As Christoph said [1],
"vm_map_ram is supposed to generally behave better.  So if
it doesn't please report that that to the arch maintainer
and linux-mm so that they can look into the issue.  Having
user make choices of deep down kernel internals is just
a horrible interface.

Please talk to maintainers of other bits of the kernel
if you see issues and / or need enhancements. "

Let's redo the previous conclusion and kill the vmap
approach.

[1] https://lore.kernel.org/r/20190830165533.GA10909@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 Documentation/filesystems/erofs.txt |  4 ----
 fs/erofs/decompressor.c             | 12 +-----------
 2 files changed, 1 insertion(+), 15 deletions(-)

diff --git a/Documentation/filesystems/erofs.txt b/Documentation/filesystems/erofs.txt
index c3b5f603b2b6..b0c085326e2e 100644
--- a/Documentation/filesystems/erofs.txt
+++ b/Documentation/filesystems/erofs.txt
@@ -67,10 +67,6 @@ cache_strategy=%s      Select a strategy for cached decompression from now on:
                                    It still does in-place I/O decompression
                                    for the rest compressed physical clusters.
 
-Module parameters
-=================
-use_vmap=[0|1]         Use vmap() instead of vm_map_ram() (default 0).
-
 On-disk details
 ===============
 
diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index bb2944c96c89..af273d89e62c 100644
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -28,10 +28,6 @@ struct z_erofs_decompressor {
 	char *name;
 };
 
-static bool use_vmap;
-module_param(use_vmap, bool, 0444);
-MODULE_PARM_DESC(use_vmap, "Use vmap() instead of vm_map_ram() (default 0)");
-
 static int z_erofs_lz4_prepare_destpages(struct z_erofs_decompress_req *rq,
 					 struct list_head *pagepool)
 {
@@ -224,9 +220,6 @@ static void *erofs_vmap(struct page **pages, unsigned int count)
 {
 	int i = 0;
 
-	if (use_vmap)
-		return vmap(pages, count, VM_MAP, PAGE_KERNEL);
-
 	while (1) {
 		void *addr = vm_map_ram(pages, count, -1, PAGE_KERNEL);
 
@@ -240,10 +233,7 @@ static void *erofs_vmap(struct page **pages, unsigned int count)
 
 static void erofs_vunmap(const void *mem, unsigned int count)
 {
-	if (!use_vmap)
-		vm_unmap_ram(mem, count);
-	else
-		vunmap(mem);
+	vm_unmap_ram(mem, count);
 }
 
 static int z_erofs_decompress_generic(struct z_erofs_decompress_req *rq,
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH 21/21] erofs: save one level of indentation
  2019-09-01  5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang
                     ` (19 preceding siblings ...)
  2019-09-01  5:51   ` [PATCH 20/21] erofs: kill use_vmap module parameter Gao Xiang
@ 2019-09-01  5:51   ` Gao Xiang
  2019-09-02 12:31     ` Christoph Hellwig
  2019-09-02 12:46   ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Christoph Hellwig
  2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
  22 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-01  5:51 UTC (permalink / raw)
  To: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman
  Cc: linux-fsdevel, devel, linux-erofs, Chao Yu, Gao Xiang

From: Gao Xiang <gaoxiang25@huawei.com>

As Christoph said [1], ".. and save one
level of indentation."

[1] https://lore.kernel.org/r/20190829102426.GE20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/inode.c | 65 ++++++++++++++++++++++++------------------------
 1 file changed, 33 insertions(+), 32 deletions(-)

diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index fcc16d2d10cb..ee39b32bb911 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -188,41 +188,42 @@ static int erofs_fill_inode(struct inode *inode, int isdir)
 	data = page_address(page);
 
 	err = erofs_read_inode(inode, data + ofs);
-	if (!err) {
-		/* setup the new inode */
-		switch (inode->i_mode & S_IFMT) {
-		case S_IFREG:
-			inode->i_op = &erofs_generic_iops;
-			inode->i_fop = &generic_ro_fops;
-			break;
-		case S_IFDIR:
-			inode->i_op = &erofs_dir_iops;
-			inode->i_fop = &erofs_dir_fops;
-			break;
-		case S_IFLNK:
-			err = erofs_fill_symlink(inode, data, ofs);
-			if (err)
-				goto out_unlock;
-			inode_nohighmem(inode);
-			break;
-		case S_IFCHR:
-		case S_IFBLK:
-		case S_IFIFO:
-		case S_IFSOCK:
-			inode->i_op = &erofs_generic_iops;
-			init_special_inode(inode, inode->i_mode, inode->i_rdev);
-			goto out_unlock;
-		default:
-			err = -EFSCORRUPTED;
+	if (err)
+		goto out_unlock;
+
+	/* setup the new inode */
+	switch (inode->i_mode & S_IFMT) {
+	case S_IFREG:
+		inode->i_op = &erofs_generic_iops;
+		inode->i_fop = &generic_ro_fops;
+		break;
+	case S_IFDIR:
+		inode->i_op = &erofs_dir_iops;
+		inode->i_fop = &erofs_dir_fops;
+		break;
+	case S_IFLNK:
+		err = erofs_fill_symlink(inode, data, ofs);
+		if (err)
 			goto out_unlock;
-		}
+		inode_nohighmem(inode);
+		break;
+	case S_IFCHR:
+	case S_IFBLK:
+	case S_IFIFO:
+	case S_IFSOCK:
+		inode->i_op = &erofs_generic_iops;
+		init_special_inode(inode, inode->i_mode, inode->i_rdev);
+		goto out_unlock;
+	default:
+		err = -EFSCORRUPTED;
+		goto out_unlock;
+	}
 
-		if (erofs_inode_is_data_compressed(vi->datamode)) {
-			err = z_erofs_fill_inode(inode);
-			goto out_unlock;
-		}
-		inode->i_mapping->a_ops = &erofs_raw_access_aops;
+	if (erofs_inode_is_data_compressed(vi->datamode)) {
+		err = z_erofs_fill_inode(inode);
+		goto out_unlock;
 	}
+	inode->i_mapping->a_ops = &erofs_raw_access_aops;
 
 out_unlock:
 	unlock_page(page);
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 01/24] erofs: add on-disk layout
  2019-08-29  9:59   ` Christoph Hellwig
  2019-08-29 10:32     ` Gao Xiang
  2019-08-29 15:41     ` Gao Xiang
@ 2019-09-01  7:54     ` Gao Xiang
  2019-09-02 12:45       ` Christoph Hellwig
  2019-09-02  8:40     ` Pavel Machek
  3 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-01  7:54 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Gao Xiang, Jan Kara, Dave Chinner, LKML, Miao Xie, devel,
	Stephen Rothwell, Darrick J . Wong, Linus Torvalds,
	Amir Goldstein, Alexander Viro, Jaegeuk Kim, Theodore Ts'o,
	Pavel Machek, David Sterba, Greg Kroah-Hartman, linux-fsdevel,
	Andrew Morton, linux-erofs

Hi Christoph,

Sorry about my first response, sincerely...
Here is my redo-ed comments to all your suggestions...

On Thu, Aug 29, 2019 at 02:59:54AM -0700, Christoph Hellwig wrote:
> > --- /dev/null
> > +++ b/fs/erofs/erofs_fs.h
> > @@ -0,0 +1,316 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only OR Apache-2.0 */
> > +/*
> > + * linux/fs/erofs/erofs_fs.h
> 
> Please remove the pointless file names in the comment headers.

Has already fixed in the latest version, and I will resend
the whole v9 addressing all suggestions from you these days...

However it's somewhat hard to spilt the whole code prefectly
since erofs is ~7KLOC code and linux-fsdevel mailing list
have some limitation, I have spilted it in the form of features...

> 
> > +struct erofs_super_block {
> > +/*  0 */__le32 magic;           /* in the little endian */
> > +/*  4 */__le32 checksum;        /* crc32c(super_block) */
> > +/*  8 */__le32 features;        /* (aka. feature_compat) */
> > +/* 12 */__u8 blkszbits;         /* support block_size == PAGE_SIZE only */
> 
> Please remove all the byte offset comments.  That is something that can
> easily be checked with gdb or pahole.

fixed in
https://lore.kernel.org/linux-fsdevel/20190901055130.30572-2-hsiangkao@aol.com/

> 
> > +/* 64 */__u8 volume_name[16];   /* volume name */
> > +/* 80 */__le32 requirements;    /* (aka. feature_incompat) */
> > +
> > +/* 84 */__u8 reserved2[44];
> > +} __packed;                     /* 128 bytes */
> 
> Please don't add __packed.  In this case I think you don't need it
> (but double check with pahole), but even if you would need it using
> proper padding fields and making sure all fields are naturally aligned
> will give you much better code generation on architectures that don't
> support native unaligned access.

fixed in
https://lore.kernel.org/linux-fsdevel/20190901055130.30572-5-hsiangkao@aol.com/

> 
> > +/*
> > + * erofs inode data mapping:
> > + * 0 - inode plain without inline data A:
> > + * inode, [xattrs], ... | ... | no-holed data
> > + * 1 - inode VLE compression B (legacy):
> > + * inode, [xattrs], extents ... | ...
> > + * 2 - inode plain with inline data C:
> > + * inode, [xattrs], last_inline_data, ... | ... | no-holed data
> > + * 3 - inode compression D:
> > + * inode, [xattrs], map_header, extents ... | ...
> > + * 4~7 - reserved
> > + */
> > +enum {
> > +	EROFS_INODE_FLAT_PLAIN,
> 
> This one doesn't actually seem to be used.

It could be better has a name though, because 1) erofs.mkfs uses this
definition explicitly, and we keep this on-disk definition erofs_fs.h
file up with erofs-utils.

2) For kernel use, first we have,
   datamode < EROFS_INODE_LAYOUT_MAX; and
   !erofs_inode_is_data_compressed, so there are only two mode here,
        1) EROFS_INODE_FLAT_INLINE,
        2) EROFS_INODE_FLAT_PLAIN
   if its datamode isn't EROFS_INODE_FLAT_INLINE (tail-end block packing),
   it should be EROFS_INODE_FLAT_PLAIN.

   The detailed logic in erofs_read_inode and
   erofs_map_blocks_flatmode....

> 
> > +	EROFS_INODE_FLAT_COMPRESSION_LEGACY,
> 
> why are we adding a legacy field to a brand new file system?

The difference is just EROFS_INODE_FLAT_COMPRESSION_LEGACY doesn't
have z_erofs_map_header, so it only supports default (4k clustersize)
fixed-sized output compression rather than per-file setting, nothing
special at all...

> 
> > +	EROFS_INODE_FLAT_INLINE,
> > +	EROFS_INODE_FLAT_COMPRESSION,
> > +	EROFS_INODE_LAYOUT_MAX
> 
> It seems like these come from the on-disk format, in which case they
> should have explicit values assigned to them.

Fixed in
https://lore.kernel.org/linux-fsdevel/20190901055130.30572-3-hsiangkao@aol.com/

> 
> Btw, I think it generally helps file system implementation quality
> if you use a separate header for the on-disk structures vs in-memory
> structures, as that keeps it clear in everyones mind what needs to
> stay persistent and what can be chenged easily.

All fields in this file are on-disk representation by design
(no logic for in-memory presentation).

> 
> > +static bool erofs_inode_is_data_compressed(unsigned int datamode)
> > +{
> > +	if (datamode == EROFS_INODE_FLAT_COMPRESSION)
> > +		return true;
> > +	return datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY;
> > +}
> 
> This looks like a really obsfucated way to write:
> 
> 	return datamode == EROFS_INODE_FLAT_COMPRESSION ||
> 		datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY;

Fixed in
https://lore.kernel.org/linux-fsdevel/20190901055130.30572-6-hsiangkao@aol.com/

> 
> > +/* 28 */__le32 i_reserved2;
> > +} __packed;
> 
> Sane comment as above.

Fixed in
https://lore.kernel.org/linux-fsdevel/20190901055130.30572-5-hsiangkao@aol.com/

> 
> > +
> > +/* 32 bytes on-disk inode */
> > +#define EROFS_INODE_LAYOUT_V1   0
> > +/* 64 bytes on-disk inode */
> > +#define EROFS_INODE_LAYOUT_V2   1
> > +
> > +struct erofs_inode_v2 {
> > +/*  0 */__le16 i_advise;
> 
> Why do we have two inode version in a newly added file system?

There is no new or old, both can be used for the current EROFS in one image.

v2 is an exhanced on-disk inode form, it has 64 bytes,
v1 is more reduced one, which is already suitable for Android use case.

> 
> > +#define ondisk_xattr_ibody_size(count)	({\
> > +	u32 __count = le16_to_cpu(count); \
> > +	((__count) == 0) ? 0 : \
> > +	sizeof(struct erofs_xattr_ibody_header) + \
> > +		sizeof(__u32) * ((__count) - 1); })
> 
> This would be much more readable as a function.

Fixed in
https://lore.kernel.org/linux-fsdevel/20190901055130.30572-4-hsiangkao@aol.com/
> 
> > +#define EROFS_XATTR_ENTRY_SIZE(entry) EROFS_XATTR_ALIGN( \
> > +	sizeof(struct erofs_xattr_entry) + \
> > +	(entry)->e_name_len + le16_to_cpu((entry)->e_value_size))
> 
> Same here.

Fixed in
https://lore.kernel.org/linux-fsdevel/20190901055130.30572-4-hsiangkao@aol.com/

> 
> > +/* available compression algorithm types */
> > +enum {
> > +	Z_EROFS_COMPRESSION_LZ4,
> > +	Z_EROFS_COMPRESSION_MAX
> > +};
> 
> Seems like an on-disk value again that should use explicitly assigned
> numbers.

Fixed in
https://lore.kernel.org/linux-fsdevel/20190901055130.30572-3-hsiangkao@aol.com/

Thanks,
Gao Xiang


^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 03/24] erofs: add super block operations
  2019-08-29 10:15   ` Christoph Hellwig
  2019-08-29 10:50     ` Gao Xiang
@ 2019-09-01  8:54     ` Gao Xiang
  2019-09-02 12:51       ` Christoph Hellwig
  1 sibling, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-01  8:54 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Gao Xiang, Jan Kara, Chao Yu, Dave Chinner, LKML, Miao Xie,
	devel, Stephen Rothwell, Darrick J . Wong, Linus Torvalds,
	Amir Goldstein, Alexander Viro, Jaegeuk Kim, Theodore Ts'o,
	Pavel Machek, David Sterba, Li Guifu, Fang Wei,
	Greg Kroah-Hartman, linux-fsdevel, Andrew Morton, linux-erofs

Hi Christoph,

Here is also my redo-ed comments...

On Thu, Aug 29, 2019 at 03:15:45AM -0700, Christoph Hellwig wrote:
> On Fri, Aug 02, 2019 at 08:53:26PM +0800, Gao Xiang wrote:
> > +static int __init erofs_init_inode_cache(void)
> > +{
> > +	erofs_inode_cachep = kmem_cache_create("erofs_inode",
> > +					       sizeof(struct erofs_vnode), 0,
> > +					       SLAB_RECLAIM_ACCOUNT,
> > +					       init_once);
> > +
> > +	return erofs_inode_cachep ? 0 : -ENOMEM;
> 
> Please just use normal if/else.  Also having this function seems
> entirely pointless.

Fixed in
https://lore.kernel.org/r/20190901055130.30572-7-hsiangkao@aol.com/

> 
> > +static void erofs_exit_inode_cache(void)
> > +{
> > +	kmem_cache_destroy(erofs_inode_cachep);
> > +}
> 
> Same for this one.

Fixed in
https://lore.kernel.org/r/20190901055130.30572-7-hsiangkao@aol.com/

> 
> > +static void free_inode(struct inode *inode)
> 
> Please use an erofs_ prefix for all your functions.

free_inode and most short, common static functions are fixed in
https://lore.kernel.org/r/20190901055130.30572-19-hsiangkao@aol.com/

For all non-static functions, all are prefixed with "erofs_"

> 
> > +{
> > +	struct erofs_vnode *vi = EROFS_V(inode);
> 
> Why is this called vnode instead of inode?  That seems like a rather
> odd naming for a Linux file system.

Fixed in
https://lore.kernel.org/r/20190901055130.30572-8-hsiangkao@aol.com/

> 
> > +
> > +	/* be careful RCU symlink path (see ext4_inode_info->i_data)! */
> > +	if (is_inode_fast_symlink(inode))
> > +		kfree(inode->i_link);
> 
> is_inode_fast_symlink only shows up in a later patch.  And really
> obsfucates the check here in the only caller as you can just do an
> unconditional kfree here - i_link will be NULL except for the case
> where you explicitly set it.

Fixed in
https://lore.kernel.org/r/20190901055130.30572-10-hsiangkao@aol.com/

and with my following comments....
https://lore.kernel.org/r/20190831005446.GA233871@architecture4/

> 
> Also this code is nothing like ext4, so the code seems a little confusing.
> 
> > +static bool check_layout_compatibility(struct super_block *sb,
> > +				       struct erofs_super_block *layout)
> > +{
> > +	const unsigned int requirements = le32_to_cpu(layout->requirements);
> 
> Why is the variable name for the on-disk subperblock layout?  We usually
> still calls this something with sb in the name, e.g. dsb. for disk
> super block.

Fixed in
https://lore.kernel.org/r/20190901055130.30572-12-hsiangkao@aol.com/

> 
> > +	EROFS_SB(sb)->requirements = requirements;
> > +
> > +	/* check if current kernel meets all mandatory requirements */
> > +	if (requirements & (~EROFS_ALL_REQUIREMENTS)) {
> > +		errln("unidentified requirements %x, please upgrade kernel version",
> > +		      requirements & ~EROFS_ALL_REQUIREMENTS);
> > +		return false;
> > +	}
> > +	return true;
> 
> Note that normally we call this features, but that doesn't really
> matter too much.

No modification at this... (some comments already right here...)

 20 /* 128-byte erofs on-disk super block */
 21 struct erofs_super_block {
...
 24         __le32 features;        /* (aka. feature_compat) */
...
 38         __le32 requirements;    /* (aka. feature_incompat) */
...
 41 };

> 
> > +static int superblock_read(struct super_block *sb)
> > +{
> > +	struct erofs_sb_info *sbi;
> > +	struct buffer_head *bh;
> > +	struct erofs_super_block *layout;
> > +	unsigned int blkszbits;
> > +	int ret;
> > +
> > +	bh = sb_bread(sb, 0);
> 
> Is there any good reasons to use buffer heads like this in new code
> vs directly using bios?

As you said, I want it in the page cache.

The reason "why not use read_mapping_page or similar?" is simply
read_mapping_page -> .readpage -> (for bdev inode) block_read_full_page
 -> create_page_buffers anyway...

sb_bread haven't obsoleted... It has similar function though...

> 
> > +
> > +	sbi->blocks = le32_to_cpu(layout->blocks);
> > +	sbi->meta_blkaddr = le32_to_cpu(layout->meta_blkaddr);
> > +	sbi->islotbits = ffs(sizeof(struct erofs_inode_v1)) - 1;
> > +	sbi->root_nid = le16_to_cpu(layout->root_nid);
> > +	sbi->inos = le64_to_cpu(layout->inos);
> > +
> > +	sbi->build_time = le64_to_cpu(layout->build_time);
> > +	sbi->build_time_nsec = le32_to_cpu(layout->build_time_nsec);
> > +
> > +	memcpy(&sb->s_uuid, layout->uuid, sizeof(layout->uuid));
> > +	memcpy(sbi->volume_name, layout->volume_name,
> > +	       sizeof(layout->volume_name));
> 
> s_uuid should preferably be a uuid_t (assuming it is a real BE uuid,
> if it is le it should be a guid_t).

For this case, I have no idea how to deal with...
I have little knowledge about this uuid stuff, so I just copied
from f2fs... (Could be no urgent of this field...)

> 
> > +/* set up default EROFS parameters */
> > +static void default_options(struct erofs_sb_info *sbi)
> > +{
> > +}
> 
> No need to add an empty function.

My fault of spilting patches...

> 
> > +static int erofs_fill_super(struct super_block *sb, void *data, int silent)
> > +{
> > +	struct inode *inode;
> > +	struct erofs_sb_info *sbi;
> > +	int err;
> > +
> > +	infoln("fill_super, device -> %s", sb->s_id);
> > +	infoln("options -> %s", (char *)data);
> 
> That is some very verbose debug info.  We usually don't add that and
> let people trace the function instead.  Also you should probably
> implement the new mount API.
> new mount API.

Fixed in
https://lore.kernel.org/r/20190901055130.30572-13-hsiangkao@aol.com/

(For new mount API,
 https://lore.kernel.org/r/20190721040547.GF17978@ZenIV.linux.org.uk/
 , I will a look later)

> 
> > +static void erofs_kill_sb(struct super_block *sb)
> > +{
> > +	struct erofs_sb_info *sbi;
> > +
> > +	WARN_ON(sb->s_magic != EROFS_SUPER_MAGIC);
> > +	infoln("unmounting for %s", sb->s_id);
> > +
> > +	kill_block_super(sb);
> > +
> > +	sbi = EROFS_SB(sb);
> > +	if (!sbi)
> > +		return;
> > +	kfree(sbi);
> > +	sb->s_fs_info = NULL;
> > +}
> 
> Why is this needed?  You can just free your sb privatte information in
> ->put_super and wire up kill_block_super as the ->kill_sb method
> directly.

The background is Al's comments in erofs v2....
(which simplify erofs_fill_super logic)
https://lore.kernel.org/r/20190720224955.GD17978@ZenIV.linux.org.uk/

with a specific notation...
https://lore.kernel.org/r/20190721040547.GF17978@ZenIV.linux.org.uk/

"
> OTOH, for the case of NULL ->s_root ->put_super() won't be called
> at all, so in that case you need it directly in ->kill_sb().
"

Thanks,
Gao Xiang


^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 05/24] erofs: add inode operations
  2019-08-29 10:24   ` Christoph Hellwig
  2019-08-29 11:59     ` Gao Xiang
@ 2019-09-01  9:34     ` Gao Xiang
  2019-09-02 12:53       ` Christoph Hellwig
  2019-09-02 13:43       ` David Sterba
  1 sibling, 2 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-01  9:34 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Gao Xiang, Jan Kara, Dave Chinner, LKML, Miao Xie, devel,
	Stephen Rothwell, Darrick J . Wong, Linus Torvalds,
	Amir Goldstein, Alexander Viro, Jaegeuk Kim, Theodore Ts'o,
	Pavel Machek, David Sterba, Greg Kroah-Hartman, linux-fsdevel,
	Andrew Morton, linux-erofs

Hi Christoph,

Here are redo-ed comments of your suggestions...

On Thu, Aug 29, 2019 at 03:24:26AM -0700, Christoph Hellwig wrote:
> On Fri, Aug 02, 2019 at 08:53:28PM +0800, Gao Xiang wrote:
> > This adds core functions to get, read an inode.
> > It adds statx support as well.
> > 
> > Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
> > ---
> >  fs/erofs/inode.c | 291 +++++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 291 insertions(+)
> >  create mode 100644 fs/erofs/inode.c
> > 
> > diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
> > new file mode 100644
> > index 000000000000..b6ea997bc4ae
> > --- /dev/null
> > +++ b/fs/erofs/inode.c
> > @@ -0,0 +1,291 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * linux/fs/erofs/inode.c
> > + *
> > + * Copyright (C) 2017-2018 HUAWEI, Inc.
> > + *             http://www.huawei.com/
> > + * Created by Gao Xiang <gaoxiang25@huawei.com>
> > + */
> > +#include "internal.h"
> > +
> > +#include <trace/events/erofs.h>
> > +
> > +/* no locking */
> > +static int read_inode(struct inode *inode, void *data)
> > +{
> > +	struct erofs_vnode *vi = EROFS_V(inode);
> > +	struct erofs_inode_v1 *v1 = data;
> > +	const unsigned int advise = le16_to_cpu(v1->i_advise);
> > +	erofs_blk_t nblks = 0;
> > +
> > +	vi->datamode = __inode_data_mapping(advise);
> 
> What is the deal with these magic underscores here and various
> other similar helpers?

Fixed in
https://lore.kernel.org/linux-fsdevel/20190901055130.30572-17-hsiangkao@aol.com/

underscores means 'internal' in my thought, it seems somewhat
some common practice of Linux kernel, or some recent discussions
about it?... I didn't notice these discussions...

> 
> > +	/* fast symlink (following ext4) */
> 
> This actually originates in FFS.  But it is so common that the comment
> seems a little pointless.

Fixed in
https://lore.kernel.org/linux-fsdevel/20190901055130.30572-9-hsiangkao@aol.com/

> 
> > +	if (S_ISLNK(inode->i_mode) && inode->i_size < PAGE_SIZE) {
> > +		char *lnk = erofs_kmalloc(sbi, inode->i_size + 1, GFP_KERNEL);
> 
> Please just use plain kmalloc everywhere and let the normal kernel
> error injection code take care of injeting any errors.

Fixed in
https://lore.kernel.org/linux-fsdevel/20190901055130.30572-20-hsiangkao@aol.com/

> 
> > +		/* inline symlink data shouldn't across page boundary as well */
> 
> ... should not cross ..

Fixed in
https://lore.kernel.org/linux-fsdevel/20190901055130.30572-9-hsiangkao@aol.com/

> 
> > +		if (unlikely(m_pofs + inode->i_size > PAGE_SIZE)) {
> > +			DBG_BUGON(1);
> > +			kfree(lnk);
> > +			return -EIO;
> > +		}
> > +
> > +		/* get in-page inline data */
> 
> s/get/copy/, but the comment seems rather pointless.

Fixed in
https://lore.kernel.org/linux-fsdevel/20190901055130.30572-9-hsiangkao@aol.com/

> 
> > +		memcpy(lnk, data + m_pofs, inode->i_size);
> > +		lnk[inode->i_size] = '\0';
> > +
> > +		inode->i_link = lnk;
> > +		set_inode_fast_symlink(inode);
> 
> Please just set the ops directly instead of obsfucating that in a single
> caller, single line inline function.  And please set it instead of the
> normal symlink iops in the same place where you also set those.:w

Fixed in
https://lore.kernel.org/linux-fsdevel/20190901055130.30572-10-hsiangkao@aol.com/

> 
> > +	err = read_inode(inode, data + ofs);
> > +	if (!err) {
> 
> 	if (err)
> 		goto out_unlock;
> 
> .. and save one level of indentation.

Fixed in
https://lore.kernel.org/linux-fsdevel/20190901055130.30572-22-hsiangkao@aol.com/

> 
> > +		if (is_inode_layout_compression(inode)) {
> 
> The name of this helper is a little odd.  But I think just
> opencoding it seems generally cleaner anyway.

Fixed in
https://lore.kernel.org/linux-fsdevel/20190901055130.30572-11-hsiangkao@aol.com/

> 
> 
> > +			err = -ENOTSUPP;
> > +			goto out_unlock;
> > +		}
> > +
> > +		inode->i_mapping->a_ops = &erofs_raw_access_aops;
> > +
> > +		/* fill last page if inline data is available */
> > +		err = fill_inline_data(inode, data, ofs);
> 
> Well, I think you should move the is_inode_flat_inline and
> (S_ISLNK(inode->i_mode) && inode->i_size < PAGE_SIZE) checks from that
> helper here, as otherwise you make everyone wonder why you'd always
> fill out the inline data.

fill_inline_data is killed, and the similar function turns into
erofs_fill_symlink which is called at erofs_fill_inode():

 		case S_IFLNK:
-			/* by default, page_get_link is used for symlink */
-			inode->i_op = &erofs_symlink_iops;
+			err = erofs_fill_symlink(inode, data, ofs);
+			if (err)
+				goto out_unlock;
 			inode_nohighmem(inode);
 			break;

> 
> > +static inline struct inode *erofs_iget_locked(struct super_block *sb,
> > +					      erofs_nid_t nid)
> > +{
> > +	const unsigned long hashval = erofs_inode_hash(nid);
> > +
> > +#if BITS_PER_LONG >= 64
> > +	/* it is safe to use iget_locked for >= 64-bit platform */
> > +	return iget_locked(sb, hashval);
> > +#else
> > +	return iget5_locked(sb, hashval, erofs_ilookup_test_actor,
> > +		erofs_iget_set_actor, &nid);
> > +#endif
> 
> Just use the slightly more complicated 32-bit version everywhere so that
> you have a single actually tested code path.  And then remove this
> helper.

As I said before, 64-bit platforms is common currently,
I think iget_locked is enough.
https://lore.kernel.org/r/20190830184606.GA175612@architecture4/

Thanks,
Gao Xiang




^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 06/24] erofs: support special inode
  2019-08-29 10:25   ` Christoph Hellwig
@ 2019-09-01  9:39     ` Gao Xiang
  0 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-01  9:39 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Gao Xiang, Jan Kara, Dave Chinner, LKML, Miao Xie, devel,
	Stephen Rothwell, Darrick J . Wong, Linus Torvalds,
	Amir Goldstein, Alexander Viro, Jaegeuk Kim, Theodore Ts'o,
	Pavel Machek, David Sterba, Greg Kroah-Hartman, linux-fsdevel,
	Andrew Morton, linux-erofs

Hi Christoph,

On Thu, Aug 29, 2019 at 03:25:03AM -0700, Christoph Hellwig wrote:
> On Fri, Aug 02, 2019 at 08:53:29PM +0800, Gao Xiang wrote:
> > This patch adds to support special inode, such as
> > block dev, char, socket, pipe inode.
> > 
> > Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
> > ---
> >  fs/erofs/inode.c | 27 +++++++++++++++++++++++++--
> >  1 file changed, 25 insertions(+), 2 deletions(-)
> > 
> > diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
> > index b6ea997bc4ae..637bf6e4de44 100644
> > --- a/fs/erofs/inode.c
> > +++ b/fs/erofs/inode.c
> > @@ -34,7 +34,16 @@ static int read_inode(struct inode *inode, void *data)
> >  		vi->xattr_isize = ondisk_xattr_ibody_size(v2->i_xattr_icount);
> >  
> >  		inode->i_mode = le16_to_cpu(v2->i_mode);
> > -		vi->raw_blkaddr = le32_to_cpu(v2->i_u.raw_blkaddr);
> > +		if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
> > +		    S_ISLNK(inode->i_mode))
> > +			vi->raw_blkaddr = le32_to_cpu(v2->i_u.raw_blkaddr);
> > +		else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
> > +			inode->i_rdev =
> > +				new_decode_dev(le32_to_cpu(v2->i_u.rdev));
> > +		else if (S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode))
> > +			inode->i_rdev = 0;
> > +		else
> > +			return -EIO;
> 
> Please use a switch statement when dealing with the file modes to
> make everything easier to read.

Fixed in
https://lore.kernel.org/linux-fsdevel/20190901055130.30572-18-hsiangkao@aol.com/

Thanks,
Gao Xiang


^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 01/24] erofs: add on-disk layout
  2019-08-29  9:59   ` Christoph Hellwig
                       ` (2 preceding siblings ...)
  2019-09-01  7:54     ` Gao Xiang
@ 2019-09-02  8:40     ` Pavel Machek
  2019-09-02 10:35       ` Gao Xiang
  3 siblings, 1 reply; 159+ messages in thread
From: Pavel Machek @ 2019-09-02  8:40 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Gao Xiang, Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek, David Sterba,
	Amir Goldstein, Darrick J . Wong, Dave Chinner, Jaegeuk Kim,
	Jan Kara, Linus Torvalds, linux-fsdevel, devel, LKML,
	linux-erofs, Chao Yu, Miao Xie, Li Guifu, Fang Wei

[-- Attachment #1: Type: text/plain, Size: 1655 bytes --]

Hi!

> > +struct erofs_super_block {
> > +/*  0 */__le32 magic;           /* in the little endian */
> > +/*  4 */__le32 checksum;        /* crc32c(super_block) */
> > +/*  8 */__le32 features;        /* (aka. feature_compat) */
> > +/* 12 */__u8 blkszbits;         /* support block_size == PAGE_SIZE only */
> 
> Please remove all the byte offset comments.  That is something that can
> easily be checked with gdb or pahole.

I don't think I agree. gdb will tell you byte offsets _on one
architecture_. But filesystem is supposed to be portable between them. 

> > +/* 64 */__u8 volume_name[16];   /* volume name */
> > +/* 80 */__le32 requirements;    /* (aka. feature_incompat) */
> > +
> > +/* 84 */__u8 reserved2[44];
> > +} __packed;                     /* 128 bytes */
> 
> Please don't add __packed.  In this case I think you don't need it
> (but double check with pahole), but even if you would need it using
> proper padding fields and making sure all fields are naturally aligned
> will give you much better code generation on architectures that don't
> support native unaligned access.

This is on-disk structure, right?

drivers/staging/erofs/super.c:	struct erofs_super_block *layout;
drivers/staging/erofs/super.c:	layout = (struct erofs_super_block
*)((u8 *)bh->b_data

So __packed is right thing to do. If architecture accesses that
slowly, that's ungood, but different structures between architectures
would be really bad.

Best regards,
								Pavel
-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany

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^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 01/24] erofs: add on-disk layout
  2019-08-30 12:07         ` David Sterba
  2019-08-30 12:18           ` Gao Xiang
@ 2019-09-02  8:43           ` Pavel Machek
  2019-09-02 14:07             ` David Sterba
  1 sibling, 1 reply; 159+ messages in thread
From: Pavel Machek @ 2019-09-02  8:43 UTC (permalink / raw)
  To: dsterba, Joe Perches, Gao Xiang, Christoph Hellwig,
	Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Pavel Machek,
	Amir Goldstein, Darrick J . Wong, Dave Chinner, Jaegeuk Kim,
	Jan Kara, Linus Torvalds, linux-fsdevel, devel, LKML,
	linux-erofs, Chao Yu, Miao Xie, Li Guifu, Fang Wei

[-- Attachment #1: Type: text/plain, Size: 913 bytes --]

Hi!

> > > Rather than they didn't run "gdb" or "pahole" and change it by mistake.
> > 
> > I think Christoph is not right here.
> > 
> > Using external tools for validation is extra work
> > when necessary for understanding the code.
> 
> The advantage of using the external tools that the information about
> offsets is provably correct ...

No. gdb tells you what the actual offsets _are_.

> > The expected offset is somewhat valuable, but
> > perhaps the form is a bit off given the visual
> > run-in to the field types.
> > 
> > The extra work with this form is manipulating all
> > the offsets whenever a structure change occurs.
> 
> ... while this is error prone.

While the comment tells you what they _should be_.

								Pavel
-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany

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^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 01/24] erofs: add on-disk layout
  2019-09-02  8:40     ` Pavel Machek
@ 2019-09-02 10:35       ` Gao Xiang
  0 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-02 10:35 UTC (permalink / raw)
  To: Pavel Machek
  Cc: Christoph Hellwig, Alexander Viro, Greg Kroah-Hartman,
	Andrew Morton, Stephen Rothwell, Theodore Ts'o, David Sterba,
	Amir Goldstein, Darrick J . Wong, Dave Chinner, Jaegeuk Kim,
	Jan Kara, Linus Torvalds, linux-fsdevel, devel, LKML,
	linux-erofs, Chao Yu, Miao Xie, Li Guifu, Fang Wei

Hi Pavel,

(Thanks...)

On Mon, Sep 02, 2019 at 10:40:20AM +0200, Pavel Machek wrote:

> 
> So __packed is right thing to do. If architecture accesses that
> slowly, that's ungood, but different structures between architectures
> would be really bad.

(...a little word, it seems that Christoph was trying to say that
 it's unnecessary to __packed for this case since we designed most
 erofs on-disk format in natural alignment... Anyway, I updated,
 that seems okay...)

Thanks,
Gao Xiang

> 
> Best regards,
> 								Pavel
> -- 
> DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany



^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 01/21] erofs: remove all the byte offset comments
  2019-09-01  5:51   ` [PATCH 01/21] erofs: remove all the byte offset comments Gao Xiang
@ 2019-09-02 12:05     ` Christoph Hellwig
  0 siblings, 0 replies; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 12:05 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman, linux-fsdevel,
	devel, linux-erofs, Chao Yu, Gao Xiang

On Sun, Sep 01, 2019 at 01:51:10PM +0800, Gao Xiang wrote:
> From: Gao Xiang <gaoxiang25@huawei.com>
> 
> As Christoph suggested [1], "Please remove all the byte offset comments.
> that is something that can easily be checked with gdb or pahole."

Looks good.  If you want to keep them after the field names as someone
pointed out feel free to - I don't think it actually is very useful
but we've also heard other opinions.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 02/21] erofs: on-disk format should have explicitly assigned numbers
  2019-09-01  5:51   ` [PATCH 02/21] erofs: on-disk format should have explicitly assigned numbers Gao Xiang
@ 2019-09-02 12:05     ` Christoph Hellwig
  0 siblings, 0 replies; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 12:05 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman, linux-fsdevel,
	devel, linux-erofs, Chao Yu, Gao Xiang

On Sun, Sep 01, 2019 at 01:51:11PM +0800, Gao Xiang wrote:
>  enum {
> -	EROFS_INODE_FLAT_PLAIN,
> -	EROFS_INODE_FLAT_COMPRESSION_LEGACY,
> -	EROFS_INODE_FLAT_INLINE,
> -	EROFS_INODE_FLAT_COMPRESSION,
> +	EROFS_INODE_FLAT_PLAIN			= 0,
> +	EROFS_INODE_FLAT_COMPRESSION_LEGACY	= 1,
> +	EROFS_INODE_FLAT_INLINE			= 2,
> +	EROFS_INODE_FLAT_COMPRESSION		= 3,
>  	EROFS_INODE_LAYOUT_MAX
>  };
>  
> @@ -184,7 +184,7 @@ struct erofs_xattr_entry {
>  
>  /* available compression algorithm types */
>  enum {
> -	Z_EROFS_COMPRESSION_LZ4,
> +	Z_EROFS_COMPRESSION_LZ4	= 0,
>  	Z_EROFS_COMPRESSION_MAX
>  };

This all looks ok - it somtimes also helps to have a comment near
the numbers to indicate where they are stored, must that isn't a must.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 03/21] erofs: some macros are much more readable as a function
  2019-09-01  5:51   ` [PATCH 03/21] erofs: some macros are much more readable as a function Gao Xiang
@ 2019-09-02 12:06     ` Christoph Hellwig
  0 siblings, 0 replies; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 12:06 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman, linux-fsdevel,
	devel, linux-erofs, Chao Yu, Gao Xiang

This looks much better now.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 04/21] erofs: kill __packed for on-disk structures
  2019-09-01  5:51   ` [PATCH 04/21] erofs: kill __packed for on-disk structures Gao Xiang
@ 2019-09-02 12:06     ` Christoph Hellwig
  0 siblings, 0 replies; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 12:06 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman, linux-fsdevel,
	devel, linux-erofs, Chao Yu, Gao Xiang

On Sun, Sep 01, 2019 at 01:51:13PM +0800, Gao Xiang wrote:
> From: Gao Xiang <gaoxiang25@huawei.com>
> 
> As Christoph suggested "Please don't add __packed" [1],
> remove all __packed except struct erofs_dirent here.
> 
> Note that all on-disk fields except struct erofs_dirent
> (12 bytes with a 8-byte nid) in EROFS are naturally aligned.

Thanks.  The users of various architectures where this generates a lot
better code will thank you.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 05/21] erofs: update erofs_inode_is_data_compressed helper
  2019-09-01  5:51   ` [PATCH 05/21] erofs: update erofs_inode_is_data_compressed helper Gao Xiang
@ 2019-09-02 12:07     ` Christoph Hellwig
  0 siblings, 0 replies; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 12:07 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman, linux-fsdevel,
	devel, linux-erofs, Chao Yu, Gao Xiang

On Sun, Sep 01, 2019 at 01:51:14PM +0800, Gao Xiang wrote:
> From: Gao Xiang <gaoxiang25@huawei.com>
> 
> As Christoph said, "This looks like a really obsfucated
> way to write:
> 	return datamode == EROFS_INODE_FLAT_COMPRESSION ||
> 		datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY; "
> 
> Although I had my own consideration, it's the right way for now.

Well, if you do check one field for two values it really helps to do
the same style of check for both.  All your choice how you do the check,
but don't mix multiple styles..

So this looks good.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 06/21] erofs: kill erofs_{init,exit}_inode_cache
  2019-09-01  5:51   ` [PATCH 06/21] erofs: kill erofs_{init,exit}_inode_cache Gao Xiang
@ 2019-09-02 12:09     ` Christoph Hellwig
  0 siblings, 0 replies; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 12:09 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman, linux-fsdevel,
	devel, linux-erofs, Chao Yu, Gao Xiang

On Sun, Sep 01, 2019 at 01:51:15PM +0800, Gao Xiang wrote:
> From: Gao Xiang <gaoxiang25@huawei.com>
> 
> As Christoph said [1] "having this function seems
> entirely pointless", let's kill those.

Looks much better.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 07/21] erofs: use erofs_inode naming
  2019-09-01  5:51   ` [PATCH 07/21] erofs: use erofs_inode naming Gao Xiang
@ 2019-09-02 12:10     ` Christoph Hellwig
  2019-09-02 12:13       ` Gao Xiang
  0 siblings, 1 reply; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 12:10 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman, linux-fsdevel,
	devel, linux-erofs, Chao Yu, Gao Xiang

>  {
> -	struct erofs_vnode *vi = ptr;
> -
> -	inode_init_once(&vi->vfs_inode);
> +	inode_init_once(&((struct erofs_inode *)ptr)->vfs_inode);

Why doesn't this use EROFS_I?  This looks a little odd.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 09/21] erofs: update erofs symlink stuffs
  2019-09-01  5:51   ` [PATCH 09/21] erofs: update erofs symlink stuffs Gao Xiang
@ 2019-09-02 12:11     ` Christoph Hellwig
  0 siblings, 0 replies; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 12:11 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman, linux-fsdevel,
	devel, linux-erofs, Chao Yu, Gao Xiang

Thanks, this looks much better.

>  fs/erofs/inode.c    | 35 ++++++++++-------------------------
>  fs/erofs/internal.h | 10 ----------
>  fs/erofs/super.c    |  5 ++---
>  3 files changed, 12 insertions(+), 38 deletions(-)

And that diffstat ain't bad either.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 10/21] erofs: kill is_inode_layout_compression()
  2019-09-01  5:51   ` [PATCH 10/21] erofs: kill is_inode_layout_compression() Gao Xiang
@ 2019-09-02 12:11     ` Christoph Hellwig
  0 siblings, 0 replies; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 12:11 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman, linux-fsdevel,
	devel, linux-erofs, Chao Yu, Gao Xiang

Thanks,

this looks much better.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 11/21] erofs: use dsb instead of layout for ondisk super_block
  2019-09-01  5:51   ` [PATCH 11/21] erofs: use dsb instead of layout for ondisk super_block Gao Xiang
@ 2019-09-02 12:12     ` Christoph Hellwig
  2019-09-02 12:15       ` Gao Xiang
  0 siblings, 1 reply; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 12:12 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman, linux-fsdevel,
	devel, linux-erofs, Chao Yu, Gao Xiang

> +	dsb = (struct erofs_super_block *)((u8 *)bh->b_data +
> +					   EROFS_SUPER_OFFSET);

Not new in this patch, but that u8 cast shouldn't be needed.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 07/21] erofs: use erofs_inode naming
  2019-09-02 12:10     ` Christoph Hellwig
@ 2019-09-02 12:13       ` Gao Xiang
  2019-09-02 12:47         ` Christoph Hellwig
  0 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-02 12:13 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Gao Xiang, Chao Yu, Greg Kroah-Hartman, linux-fsdevel, devel,
	linux-erofs, Chao Yu

Hi Christoph,

On Mon, Sep 02, 2019 at 05:10:21AM -0700, Christoph Hellwig wrote:
> >  {
> > -	struct erofs_vnode *vi = ptr;
> > -
> > -	inode_init_once(&vi->vfs_inode);
> > +	inode_init_once(&((struct erofs_inode *)ptr)->vfs_inode);
> 
> Why doesn't this use EROFS_I?  This looks a little odd.

Thanks for your reply and suggestion...
EROFS_I seems the revert direction ---> inode to erofs_inode
here we need "erofs_inode" to inode...

Am I missing something?.... Hope not....

Thanks,
Gao Xiang




^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 12/21] erofs: kill verbose debug info in erofs_fill_super
  2019-09-01  5:51   ` [PATCH 12/21] erofs: kill verbose debug info in erofs_fill_super Gao Xiang
@ 2019-09-02 12:14     ` Christoph Hellwig
  2019-09-02 12:18       ` Gao Xiang
  0 siblings, 1 reply; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 12:14 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman, linux-fsdevel,
	devel, linux-erofs, Chao Yu, Gao Xiang

On Sun, Sep 01, 2019 at 01:51:21PM +0800, Gao Xiang wrote:
> From: Gao Xiang <gaoxiang25@huawei.com>
> 
> As Christoph said [1], "That is some very verbose
> debug info.  We usually don't add that and let
> people trace the function instead. "

Note that this applies to most of the infoln users as far as
I can tell.  And if you want to keep some of those I think you
should converted them to use pr_info directly, and also print
sb->s_id as a prefix before the actual message so that the user
knows which file system is affected.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 11/21] erofs: use dsb instead of layout for ondisk super_block
  2019-09-02 12:12     ` Christoph Hellwig
@ 2019-09-02 12:15       ` Gao Xiang
  0 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-02 12:15 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Gao Xiang, Chao Yu, Greg Kroah-Hartman, linux-fsdevel, devel,
	linux-erofs, Chao Yu

Hi Christoph,

On Mon, Sep 02, 2019 at 05:12:34AM -0700, Christoph Hellwig wrote:
> > +	dsb = (struct erofs_super_block *)((u8 *)bh->b_data +
> > +					   EROFS_SUPER_OFFSET);
> 
> Not new in this patch, but that u8 cast shouldn't be needed.

Yes, thanks and will fix it...

Thanks,
Gao Xiang


^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 12/21] erofs: kill verbose debug info in erofs_fill_super
  2019-09-02 12:14     ` Christoph Hellwig
@ 2019-09-02 12:18       ` Gao Xiang
  0 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-02 12:18 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Gao Xiang, Chao Yu, Greg Kroah-Hartman, linux-fsdevel, devel,
	linux-erofs, Chao Yu

Hi Christoph,

On Mon, Sep 02, 2019 at 05:14:24AM -0700, Christoph Hellwig wrote:
> On Sun, Sep 01, 2019 at 01:51:21PM +0800, Gao Xiang wrote:
> > From: Gao Xiang <gaoxiang25@huawei.com>
> > 
> > As Christoph said [1], "That is some very verbose
> > debug info.  We usually don't add that and let
> > people trace the function instead. "
> 
> Note that this applies to most of the infoln users as far as
> I can tell.  And if you want to keep some of those I think you
> should converted them to use pr_info directly, and also print
> sb->s_id as a prefix before the actual message so that the user
> knows which file system is affected.

Thanks for your suggestion...

I think I will turn them into erofs_errln and etc...
and print sb->s_id as a prefix...

Thanks,
Gao Xiang



^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 13/21] erofs: simplify erofs_grab_bio() since bio_alloc() never fail
  2019-09-01  5:51   ` [PATCH 13/21] erofs: simplify erofs_grab_bio() since bio_alloc() never fail Gao Xiang
@ 2019-09-02 12:20     ` Christoph Hellwig
  0 siblings, 0 replies; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 12:20 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman, linux-fsdevel,
	devel, linux-erofs, Chao Yu, Gao Xiang

On Sun, Sep 01, 2019 at 01:51:22PM +0800, Gao Xiang wrote:
> From: Gao Xiang <gaoxiang25@huawei.com>
> 
> As Christoph pointed out [1], "erofs_grab_bio tries to
> handle a bio_alloc failure, except that the function will
> not actually fail due the mempool backing it."
> 
> Sorry about useless code, fix it now.

A lot of file systems used to have this, it is a classic that gets
copy and pasted everywhere.  If you feel like doing a little project
it might make sense to check for other places that do the same.

> +		bio = erofs_grab_bio(sb, blkaddr, 1, sb, read_endio);
>  
>  		if (bio_add_page(bio, page, PAGE_SIZE, 0) != PAGE_SIZE) {
>  			err = -EFAULT;
> @@ -275,13 +270,7 @@ static inline struct bio *erofs_read_raw_page(struct bio *bio,
>  		if (nblocks > BIO_MAX_PAGES)
>  			nblocks = BIO_MAX_PAGES;
>  
> -		bio = erofs_grab_bio(sb, blknr, nblocks, sb,
> -				     read_endio, false);
> -		if (IS_ERR(bio)) {
> -			err = PTR_ERR(bio);
> -			bio = NULL;
> -			goto err_out;
> -		}
> +		bio = erofs_grab_bio(sb, blknr, nblocks, sb, read_endio);

Btw, I think you should remove erofs_grab_bio in its current form.
The full code in data.c is indeed used in two places, so a local
erofs_raw_page_alloc_bio (or whatever name you prefer) helper here
that hardcodes the sb amd read_endio argument to simplify it a bit
makes sense.

> diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
> index f06a2fad7af2..abe28565d6c0 100644
> --- a/fs/erofs/zdata.c
> +++ b/fs/erofs/zdata.c
> @@ -1265,7 +1265,7 @@ static bool z_erofs_vle_submit_all(struct super_block *sb,
>  		if (!bio) {
>  			bio = erofs_grab_bio(sb, first_index + i,
>  					     BIO_MAX_PAGES, bi_private,
> -					     z_erofs_vle_read_endio, true);
> +					     z_erofs_vle_read_endio);

But I think here you might as well open code it entirely, or at least
us a separate (and local to zdata.c) helper.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 14/21] erofs: kill prio and nofail of erofs_get_meta_page()
  2019-09-01  5:51   ` [PATCH 14/21] erofs: kill prio and nofail of erofs_get_meta_page() Gao Xiang
@ 2019-09-02 12:21     ` Christoph Hellwig
  0 siblings, 0 replies; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 12:21 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman, linux-fsdevel,
	devel, linux-erofs, Chao Yu, Gao Xiang

Thanks,

much better.  I'm still hoping REQ_PRIO in this current form will go
entirely away soon as well.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 16/21] erofs: kill magic underscores
  2019-09-01  5:51   ` [PATCH 16/21] erofs: kill magic underscores Gao Xiang
@ 2019-09-02 12:26     ` Christoph Hellwig
  2019-09-02 12:39       ` Gao Xiang
  0 siblings, 1 reply; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 12:26 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman, linux-fsdevel,
	devel, linux-erofs, Chao Yu, Gao Xiang

>  
> -	vi->datamode = __inode_data_mapping(advise);
> +	vi->datamode = erofs_inode_data_mapping(advise);
>  
>  	if (vi->datamode >= EROFS_INODE_LAYOUT_MAX) {

While you are at it can we aim for some naming consistency here?  The
inode member is called is called datamode, the helper is called
inode_data_mapping, and the enum uses layout?  To me data_layout seems
most descriptive, datamode is probably ok, but mapping seems very
misleading given that we've already overloaded that terms for multiple
other uses.

And while we are at naming choices - maybe i_format might be
a better name for the i_advise field in the on-disk inode?

> +	if (erofs_inode_version(advise) == EROFS_INODE_LAYOUT_V2) {

I still need to wade through the old thread - but didn't you say this
wasn't really a new vs old version but a compat vs full inode?  Maybe
the names aren't that suitable either?

>  		struct erofs_inode_v2 *v2 = data;
>  
>  		vi->inode_isize = sizeof(struct erofs_inode_v2);
> @@ -58,7 +58,7 @@ static int read_inode(struct inode *inode, void *data)
>  		/* total blocks for compressed files */
>  		if (erofs_inode_is_data_compressed(vi->datamode))
>  			nblks = le32_to_cpu(v2->i_u.compressed_blocks);
> -	} else if (__inode_version(advise) == EROFS_INODE_LAYOUT_V1) {
> +	} else if (erofs_inode_version(advise) == EROFS_INODE_LAYOUT_V1) {

Also a lot of code would use a switch statements to switch for different
matches on the same value instead of chained if/else if/else if
statements.

> +#define erofs_bitrange(x, bit, bits) (((x) >> (bit)) & ((1 << (bits)) - 1))

> +#define erofs_inode_version(advise)	\
> +	erofs_bitrange(advise, EROFS_I_VERSION_BIT, EROFS_I_VERSION_BITS)
>  
> +#define erofs_inode_data_mapping(advise)	\
> +	erofs_bitrange(advise, EROFS_I_DATA_MAPPING_BIT, \
> +		       EROFS_I_DATA_MAPPING_BITS)

All these should probably be inline functions.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 17/21] erofs: use a switch statement when dealing with the file modes
  2019-09-01  5:51   ` [PATCH 17/21] erofs: use a switch statement when dealing with the file modes Gao Xiang
@ 2019-09-02 12:27     ` Christoph Hellwig
  0 siblings, 0 replies; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 12:27 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman, linux-fsdevel,
	devel, linux-erofs, Chao Yu, Gao Xiang

Thanks,

this looks much nicer.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 18/21] erofs: add "erofs_" prefix for common and short functions
  2019-09-01  5:51   ` [PATCH 18/21] erofs: add "erofs_" prefix for common and short functions Gao Xiang
@ 2019-09-02 12:28     ` Christoph Hellwig
  0 siblings, 0 replies; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 12:28 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman, linux-fsdevel,
	devel, linux-erofs, Chao Yu, Gao Xiang

Thanks.  I don't have a tree with all these applies, but please make
sure this covers at least all inlines in headers and all methods
wired up to operation structures.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 19/21] erofs: kill all erofs specific fault injection
  2019-09-01  5:51   ` [PATCH 19/21] erofs: kill all erofs specific fault injection Gao Xiang
@ 2019-09-02 12:28     ` Christoph Hellwig
  0 siblings, 0 replies; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 12:28 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman, linux-fsdevel,
	devel, linux-erofs, Chao Yu, Gao Xiang

On Sun, Sep 01, 2019 at 01:51:28PM +0800, Gao Xiang wrote:
> From: Gao Xiang <gaoxiang25@huawei.com>
> 
> As Christoph suggested [1], "Please just use plain kmalloc
> everywhere and let the normal kernel error injection code
> take care of injeting any errors."

Thanks.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 20/21] erofs: kill use_vmap module parameter
  2019-09-01  5:51   ` [PATCH 20/21] erofs: kill use_vmap module parameter Gao Xiang
@ 2019-09-02 12:31     ` Christoph Hellwig
  2019-09-02 12:43       ` Gao Xiang
  0 siblings, 1 reply; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 12:31 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman, linux-fsdevel,
	devel, linux-erofs, Chao Yu, Gao Xiang

> @@ -224,9 +220,6 @@ static void *erofs_vmap(struct page **pages, unsigned int count)
>  {
>  	int i = 0;
>  
> -	if (use_vmap)
> -		return vmap(pages, count, VM_MAP, PAGE_KERNEL);
> -
>  	while (1) {
>  		void *addr = vm_map_ram(pages, count, -1, PAGE_KERNEL);

I think you can just open code this in the caller.

>  static void erofs_vunmap(const void *mem, unsigned int count)
>  {
> -	if (!use_vmap)
> -		vm_unmap_ram(mem, count);
> -	else
> -		vunmap(mem);
> +	vm_unmap_ram(mem, count);
>  }

And this wrapper can go away entirely.

And don't forget to report your performance observations to the arm64
maintainers!

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 21/21] erofs: save one level of indentation
  2019-09-01  5:51   ` [PATCH 21/21] erofs: save one level of indentation Gao Xiang
@ 2019-09-02 12:31     ` Christoph Hellwig
  0 siblings, 0 replies; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 12:31 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman, linux-fsdevel,
	devel, linux-erofs, Chao Yu, Gao Xiang

On Sun, Sep 01, 2019 at 01:51:30PM +0800, Gao Xiang wrote:
> From: Gao Xiang <gaoxiang25@huawei.com>
> 
> As Christoph said [1], ".. and save one
> level of indentation."

Thanks.  Just a little cleanup, but cumulated things like this really
help readability.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 16/21] erofs: kill magic underscores
  2019-09-02 12:26     ` Christoph Hellwig
@ 2019-09-02 12:39       ` Gao Xiang
  2019-09-02 12:54         ` Christoph Hellwig
  0 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-02 12:39 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Gao Xiang, Chao Yu, Greg Kroah-Hartman, linux-fsdevel, devel,
	linux-erofs, Chao Yu

Hi Christoph,

On Mon, Sep 02, 2019 at 05:26:27AM -0700, Christoph Hellwig wrote:
> >  
> > -	vi->datamode = __inode_data_mapping(advise);
> > +	vi->datamode = erofs_inode_data_mapping(advise);
> >  
> >  	if (vi->datamode >= EROFS_INODE_LAYOUT_MAX) {
> 
> While you are at it can we aim for some naming consistency here?  The
> inode member is called is called datamode, the helper is called
> inode_data_mapping, and the enum uses layout?  To me data_layout seems
> most descriptive, datamode is probably ok, but mapping seems very
> misleading given that we've already overloaded that terms for multiple
> other uses.

the naming changed for many times...
Initially, it was called "data_mapping_mode", and I think it was too long
(and as you said confusing, since confusing "mapping" meaning, sorry about
my awkward  English) so I simplified some into datamode....

In a word, I will change all data_mapping_mode into datalayout....

> 
> And while we are at naming choices - maybe i_format might be
> a better name for the i_advise field in the on-disk inode?

That is a good idea, I will resend v2 to address it...

> 
> > +	if (erofs_inode_version(advise) == EROFS_INODE_LAYOUT_V2) {
> 
> I still need to wade through the old thread - but didn't you say this
> wasn't really a new vs old version but a compat vs full inode?  Maybe
> the names aren't that suitable either?

Could you kindly give some suggestions for better naming about it?
there are all supported by EROFS... (Actually we only mainly use v1...)

> 
> >  		struct erofs_inode_v2 *v2 = data;
> >  
> >  		vi->inode_isize = sizeof(struct erofs_inode_v2);
> > @@ -58,7 +58,7 @@ static int read_inode(struct inode *inode, void *data)
> >  		/* total blocks for compressed files */
> >  		if (erofs_inode_is_data_compressed(vi->datamode))
> >  			nblks = le32_to_cpu(v2->i_u.compressed_blocks);
> > -	} else if (__inode_version(advise) == EROFS_INODE_LAYOUT_V1) {
> > +	} else if (erofs_inode_version(advise) == EROFS_INODE_LAYOUT_V1) {
> 
> Also a lot of code would use a switch statements to switch for different
> matches on the same value instead of chained if/else if/else if
> statements.

I will change it as well.

> 
> > +#define erofs_bitrange(x, bit, bits) (((x) >> (bit)) & ((1 << (bits)) - 1))
> 
> > +#define erofs_inode_version(advise)	\
> > +	erofs_bitrange(advise, EROFS_I_VERSION_BIT, EROFS_I_VERSION_BITS)
> >  
> > +#define erofs_inode_data_mapping(advise)	\
> > +	erofs_bitrange(advise, EROFS_I_DATA_MAPPING_BIT, \
> > +		       EROFS_I_DATA_MAPPING_BITS)
> 
> All these should probably be inline functions.

Will fix...

Thanks,
Gao Xiang


^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 20/21] erofs: kill use_vmap module parameter
  2019-09-02 12:31     ` Christoph Hellwig
@ 2019-09-02 12:43       ` Gao Xiang
  0 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-02 12:43 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Gao Xiang, Chao Yu, Greg Kroah-Hartman, linux-fsdevel, devel,
	linux-erofs, Chao Yu

Hi Christoph,

On Mon, Sep 02, 2019 at 05:31:24AM -0700, Christoph Hellwig wrote:
> > @@ -224,9 +220,6 @@ static void *erofs_vmap(struct page **pages, unsigned int count)
> >  {
> >  	int i = 0;
> >  
> > -	if (use_vmap)
> > -		return vmap(pages, count, VM_MAP, PAGE_KERNEL);
> > -
> >  	while (1) {
> >  		void *addr = vm_map_ram(pages, count, -1, PAGE_KERNEL);
> 
> I think you can just open code this in the caller.

Yes, the only one user... will fix...

> 
> >  static void erofs_vunmap(const void *mem, unsigned int count)
> >  {
> > -	if (!use_vmap)
> > -		vm_unmap_ram(mem, count);
> > -	else
> > -		vunmap(mem);
> > +	vm_unmap_ram(mem, count);
> >  }
> 
> And this wrapper can go away entirely.

Got it. will fix.

> 
> And don't forget to report your performance observations to the arm64
> maintainers!

In my observation, vm_map_ram always performs better...
If there are something strange later, I will report to them
immediately... :)

Thanks,
Gao Xiang


^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 01/24] erofs: add on-disk layout
  2019-09-01  7:54     ` Gao Xiang
@ 2019-09-02 12:45       ` Christoph Hellwig
  2019-09-02 13:02         ` Gao Xiang
  0 siblings, 1 reply; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 12:45 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Gao Xiang, Jan Kara, Dave Chinner, LKML,
	Miao Xie, devel, Stephen Rothwell, Darrick J . Wong,
	Linus Torvalds, Amir Goldstein, Alexander Viro, Jaegeuk Kim,
	Theodore Ts'o, Pavel Machek, David Sterba,
	Greg Kroah-Hartman, linux-fsdevel, Andrew Morton, linux-erofs

On Sun, Sep 01, 2019 at 03:54:11PM +0800, Gao Xiang wrote:
> It could be better has a name though, because 1) erofs.mkfs uses this
> definition explicitly, and we keep this on-disk definition erofs_fs.h
> file up with erofs-utils.
> 
> 2) For kernel use, first we have,
>    datamode < EROFS_INODE_LAYOUT_MAX; and
>    !erofs_inode_is_data_compressed, so there are only two mode here,
>         1) EROFS_INODE_FLAT_INLINE,
>         2) EROFS_INODE_FLAT_PLAIN
>    if its datamode isn't EROFS_INODE_FLAT_INLINE (tail-end block packing),
>    it should be EROFS_INODE_FLAT_PLAIN.
> 
>    The detailed logic in erofs_read_inode and
>    erofs_map_blocks_flatmode....

Ok.  At least the explicit numbering makes this a little more obvious
now.  What seems fairly odd is that there are only various places that
check for some inode layouts/formats but nothing that does a switch
over all of them.

> > why are we adding a legacy field to a brand new file system?
> 
> The difference is just EROFS_INODE_FLAT_COMPRESSION_LEGACY doesn't
> have z_erofs_map_header, so it only supports default (4k clustersize)
> fixed-sized output compression rather than per-file setting, nothing
> special at all...

It still seems odd to add a legacy field to a brand new file system.

> > structures, as that keeps it clear in everyones mind what needs to
> > stay persistent and what can be chenged easily.
> 
> All fields in this file are on-disk representation by design
> (no logic for in-memory presentation).

Ok, make sense.    Maybe add a note to the top of the file comment
that this is the on-disk format.

One little oddity is that erofs_inode_is_data_compressed is here, while
is_inode_flat_inline is in internal.h.  There are arguments for either
place, but I'd suggest to keep the related macros together.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 00/21] erofs: patchset addressing Christoph's comments
  2019-09-01  5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang
                     ` (20 preceding siblings ...)
  2019-09-01  5:51   ` [PATCH 21/21] erofs: save one level of indentation Gao Xiang
@ 2019-09-02 12:46   ` Christoph Hellwig
  2019-09-02 14:24     ` Gao Xiang
  2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
  22 siblings, 1 reply; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 12:46 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Chao Yu, Greg Kroah-Hartman, linux-fsdevel,
	devel, linux-erofs, Chao Yu

On Sun, Sep 01, 2019 at 01:51:09PM +0800, Gao Xiang wrote:
> Hi,
> 
> This patchset is based on the following patch by Pratik Shinde,
> https://lore.kernel.org/linux-erofs/20190830095615.10995-1-pratikshinde320@gmail.com/
> 
> All patches addressing Christoph's comments on v6, which are trivial,
> most deleted code are from erofs specific fault injection, which was
> followed f2fs and previously discussed in earlier topic [1], but
> let's follow what Christoph's said now.

I like where the cleanups are going.  But this is really just basic
code quality stuff.  We're not addressing the issues with large amounts
of functionality duplicating VFS helpers.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 07/21] erofs: use erofs_inode naming
  2019-09-02 12:13       ` Gao Xiang
@ 2019-09-02 12:47         ` Christoph Hellwig
  2019-09-02 13:33           ` Gao Xiang
  0 siblings, 1 reply; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 12:47 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Gao Xiang, Chao Yu, Greg Kroah-Hartman,
	linux-fsdevel, devel, linux-erofs, Chao Yu

On Mon, Sep 02, 2019 at 08:13:06PM +0800, Gao Xiang wrote:
> Hi Christoph,
> 
> On Mon, Sep 02, 2019 at 05:10:21AM -0700, Christoph Hellwig wrote:
> > >  {
> > > -	struct erofs_vnode *vi = ptr;
> > > -
> > > -	inode_init_once(&vi->vfs_inode);
> > > +	inode_init_once(&((struct erofs_inode *)ptr)->vfs_inode);
> > 
> > Why doesn't this use EROFS_I?  This looks a little odd.
> 
> Thanks for your reply and suggestion...
> EROFS_I seems the revert direction ---> inode to erofs_inode
> here we need "erofs_inode" to inode...
> 
> Am I missing something?.... Hope not....

No, you are not.  But the cast still looks odd.  Why not:

	struct erofs_inode *ei = ptr;

	inode_init_once(&ei->vfs_inode);

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 03/24] erofs: add super block operations
  2019-09-01  8:54     ` Gao Xiang
@ 2019-09-02 12:51       ` Christoph Hellwig
  2019-09-02 14:43         ` Gao Xiang
  0 siblings, 1 reply; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 12:51 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Gao Xiang, Jan Kara, Chao Yu, Dave Chinner,
	LKML, Miao Xie, devel, Stephen Rothwell, Darrick J . Wong,
	Linus Torvalds, Amir Goldstein, Alexander Viro, Jaegeuk Kim,
	Theodore Ts'o, Pavel Machek, David Sterba, Li Guifu,
	Fang Wei, Greg Kroah-Hartman, linux-fsdevel, Andrew Morton,
	linux-erofs

On Sun, Sep 01, 2019 at 04:54:55PM +0800, Gao Xiang wrote:
> No modification at this... (some comments already right here...)

>  20 /* 128-byte erofs on-disk super block */
>  21 struct erofs_super_block {
> ...
>  24         __le32 features;        /* (aka. feature_compat) */
> ...
>  38         __le32 requirements;    /* (aka. feature_incompat) */
> ...
>  41 };

This is only cosmetic, why not stick to feature_compat and
feature_incompat?

> > > +	bh = sb_bread(sb, 0);
> > 
> > Is there any good reasons to use buffer heads like this in new code
> > vs directly using bios?
> 
> As you said, I want it in the page cache.
> 
> The reason "why not use read_mapping_page or similar?" is simply
> read_mapping_page -> .readpage -> (for bdev inode) block_read_full_page
>  -> create_page_buffers anyway...
> 
> sb_bread haven't obsoleted... It has similar function though...

With the different that it keeps you isolated from the buffer_head
internals.  This seems to be your only direct use of buffer heads,
which while not deprecated are a bit of an ugly step child.  So if
you can easily avoid creating a buffer_head dependency in a new
filesystem I think you should avoid it.

> > > +	sbi->build_time = le64_to_cpu(layout->build_time);
> > > +	sbi->build_time_nsec = le32_to_cpu(layout->build_time_nsec);
> > > +
> > > +	memcpy(&sb->s_uuid, layout->uuid, sizeof(layout->uuid));
> > > +	memcpy(sbi->volume_name, layout->volume_name,
> > > +	       sizeof(layout->volume_name));
> > 
> > s_uuid should preferably be a uuid_t (assuming it is a real BE uuid,
> > if it is le it should be a guid_t).
> 
> For this case, I have no idea how to deal with...
> I have little knowledge about this uuid stuff, so I just copied
> from f2fs... (Could be no urgent of this field...)

Who fills out this field in the on-disk format and how?

> The background is Al's comments in erofs v2....
> (which simplify erofs_fill_super logic)
> https://lore.kernel.org/r/20190720224955.GD17978@ZenIV.linux.org.uk/
> 
> with a specific notation...
> https://lore.kernel.org/r/20190721040547.GF17978@ZenIV.linux.org.uk/
> 
> "
> > OTOH, for the case of NULL ->s_root ->put_super() won't be called
> > at all, so in that case you need it directly in ->kill_sb().
> "

Yes.  Although none of that is relevant for this initial version,
just after more features are added.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 05/24] erofs: add inode operations
  2019-09-01  9:34     ` Gao Xiang
@ 2019-09-02 12:53       ` Christoph Hellwig
  2019-09-02 13:43       ` David Sterba
  1 sibling, 0 replies; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 12:53 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Gao Xiang, Jan Kara, Dave Chinner, LKML,
	Miao Xie, devel, Stephen Rothwell, Darrick J . Wong,
	Linus Torvalds, Amir Goldstein, Alexander Viro, Jaegeuk Kim,
	Theodore Ts'o, Pavel Machek, David Sterba,
	Greg Kroah-Hartman, linux-fsdevel, Andrew Morton, linux-erofs

On Sun, Sep 01, 2019 at 05:34:00PM +0800, Gao Xiang wrote:
> > > +	return iget5_locked(sb, hashval, erofs_ilookup_test_actor,
> > > +		erofs_iget_set_actor, &nid);
> > > +#endif
> > 
> > Just use the slightly more complicated 32-bit version everywhere so that
> > you have a single actually tested code path.  And then remove this
> > helper.
> 
> As I said before, 64-bit platforms is common currently,
> I think iget_locked is enough.
> https://lore.kernel.org/r/20190830184606.GA175612@architecture4/

The problem with that is that you now have two entirely different
code paths.  And the 32-bit one will probably get very little testing
and eventually bitrot.  We defintively had problems of that sort in
XFS in the past, so my suggestion is to not go down the root of
separate code for 32-bit vs 64-bit unless it makes a real difference
for a real-life workload.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 16/21] erofs: kill magic underscores
  2019-09-02 12:39       ` Gao Xiang
@ 2019-09-02 12:54         ` Christoph Hellwig
  2019-09-02 13:38           ` Gao Xiang
  0 siblings, 1 reply; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 12:54 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Gao Xiang, Chao Yu, Greg Kroah-Hartman,
	linux-fsdevel, devel, linux-erofs, Chao Yu

On Mon, Sep 02, 2019 at 08:39:37PM +0800, Gao Xiang wrote:
> > 
> > > +	if (erofs_inode_version(advise) == EROFS_INODE_LAYOUT_V2) {
> > 
> > I still need to wade through the old thread - but didn't you say this
> > wasn't really a new vs old version but a compat vs full inode?  Maybe
> > the names aren't that suitable either?
> 
> Could you kindly give some suggestions for better naming about it?
> there are all supported by EROFS... (Actually we only mainly use v1...)

Maybe EROFS_INODE_LAYOUT_COMPACT and EROFS_INODE_LAYOUT_EXTENDED?

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 01/24] erofs: add on-disk layout
  2019-09-02 12:45       ` Christoph Hellwig
@ 2019-09-02 13:02         ` Gao Xiang
  0 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-02 13:02 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Gao Xiang, Jan Kara, Dave Chinner, LKML, Miao Xie, devel,
	Stephen Rothwell, Darrick J . Wong, Linus Torvalds,
	Amir Goldstein, Alexander Viro, Jaegeuk Kim, Theodore Ts'o,
	Pavel Machek, David Sterba, Greg Kroah-Hartman, linux-fsdevel,
	Andrew Morton, linux-erofs

Hi Christoph,

On Mon, Sep 02, 2019 at 05:45:21AM -0700, Christoph Hellwig wrote:
> On Sun, Sep 01, 2019 at 03:54:11PM +0800, Gao Xiang wrote:
> > It could be better has a name though, because 1) erofs.mkfs uses this
> > definition explicitly, and we keep this on-disk definition erofs_fs.h
> > file up with erofs-utils.
> > 
> > 2) For kernel use, first we have,
> >    datamode < EROFS_INODE_LAYOUT_MAX; and
> >    !erofs_inode_is_data_compressed, so there are only two mode here,
> >         1) EROFS_INODE_FLAT_INLINE,
> >         2) EROFS_INODE_FLAT_PLAIN
> >    if its datamode isn't EROFS_INODE_FLAT_INLINE (tail-end block packing),
> >    it should be EROFS_INODE_FLAT_PLAIN.
> > 
> >    The detailed logic in erofs_read_inode and
> >    erofs_map_blocks_flatmode....
> 
> Ok.  At least the explicit numbering makes this a little more obvious
> now.  What seems fairly odd is that there are only various places that
> check for some inode layouts/formats but nothing that does a switch
> over all of them.

(Maybe not explicitly for this part....)

erofs_map_blocks_flatmode()
...
 97         nblocks = DIV_ROUND_UP(inode->i_size, PAGE_SIZE);
 98         lastblk = nblocks - is_inode_flat_inline(inode);
                                ^ here
...

Believe me EROFS_INODE_FLAT_PLAIN is used widely for EROFS images....
(if EROFS_INODE_FLAT_INLINE tail-end packing is not suitable and
 no compression....)

> 
> > > why are we adding a legacy field to a brand new file system?
> > 
> > The difference is just EROFS_INODE_FLAT_COMPRESSION_LEGACY doesn't
> > have z_erofs_map_header, so it only supports default (4k clustersize)
> > fixed-sized output compression rather than per-file setting, nothing
> > special at all...
> 
> It still seems odd to add a legacy field to a brand new file system.

Since 4.19 EROFS only supports EROFS_INODE_FLAT_COMPRESSION_LEGACY
(per-filesystem setting), we'd like to introduce per-file setting and
more configration for future requirements....

> 
> > > structures, as that keeps it clear in everyones mind what needs to
> > > stay persistent and what can be chenged easily.
> > 
> > All fields in this file are on-disk representation by design
> > (no logic for in-memory presentation).
> 
> Ok, make sense.    Maybe add a note to the top of the file comment
> that this is the on-disk format.
> 
> One little oddity is that erofs_inode_is_data_compressed is here, while
> is_inode_flat_inline is in internal.h.  There are arguments for either
> place, but I'd suggest to keep the related macros together.

(Just my personal thought... erofs_inode_is_data_compressed operates
ondisk field like datamode (because we have 2 datamode for compression,
need to wrap them to judge if the file is compressed...)
so it stays at erofs_fs.h... is_inode_flat_inline operates in-memory
struct inode so it in internal.h....)

Thanks,
Gao Xiang


^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 07/21] erofs: use erofs_inode naming
  2019-09-02 12:47         ` Christoph Hellwig
@ 2019-09-02 13:33           ` Gao Xiang
  0 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-02 13:33 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Gao Xiang, Chao Yu, Greg Kroah-Hartman, linux-fsdevel, devel,
	linux-erofs, Chao Yu

Hi Christoph,

On Mon, Sep 02, 2019 at 05:47:37AM -0700, Christoph Hellwig wrote:
> On Mon, Sep 02, 2019 at 08:13:06PM +0800, Gao Xiang wrote:
> > Hi Christoph,
> > 
> > On Mon, Sep 02, 2019 at 05:10:21AM -0700, Christoph Hellwig wrote:
> > > >  {
> > > > -	struct erofs_vnode *vi = ptr;
> > > > -
> > > > -	inode_init_once(&vi->vfs_inode);
> > > > +	inode_init_once(&((struct erofs_inode *)ptr)->vfs_inode);
> > > 
> > > Why doesn't this use EROFS_I?  This looks a little odd.
> > 
> > Thanks for your reply and suggestion...
> > EROFS_I seems the revert direction ---> inode to erofs_inode
> > here we need "erofs_inode" to inode...
> > 
> > Am I missing something?.... Hope not....
> 
> No, you are not.  But the cast still looks odd.  Why not:
> 
> 	struct erofs_inode *ei = ptr;
> 
> 	inode_init_once(&ei->vfs_inode);

That is the old way, I thought you don't like the extra variable...
https://lore.kernel.org/linux-erofs/20190830154551.GA11571@infradead.org/
I am ok with either form, anyway, let me use the old way....

Thanks,
Gao Xiang


^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 16/21] erofs: kill magic underscores
  2019-09-02 12:54         ` Christoph Hellwig
@ 2019-09-02 13:38           ` Gao Xiang
  0 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-02 13:38 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Gao Xiang, Chao Yu, Greg Kroah-Hartman, linux-fsdevel, devel,
	linux-erofs, Chao Yu

Hi Christoph,

On Mon, Sep 02, 2019 at 05:54:38AM -0700, Christoph Hellwig wrote:
> On Mon, Sep 02, 2019 at 08:39:37PM +0800, Gao Xiang wrote:
> > > 
> > > > +	if (erofs_inode_version(advise) == EROFS_INODE_LAYOUT_V2) {
> > > 
> > > I still need to wade through the old thread - but didn't you say this
> > > wasn't really a new vs old version but a compat vs full inode?  Maybe
> > > the names aren't that suitable either?
> > 
> > Could you kindly give some suggestions for better naming about it?
> > there are all supported by EROFS... (Actually we only mainly use v1...)
> 
> Maybe EROFS_INODE_LAYOUT_COMPACT and EROFS_INODE_LAYOUT_EXTENDED?

Okay, that is fine.

Thanks,
Gao Xiang


^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 05/24] erofs: add inode operations
  2019-09-01  9:34     ` Gao Xiang
  2019-09-02 12:53       ` Christoph Hellwig
@ 2019-09-02 13:43       ` David Sterba
  2019-09-02 13:55         ` Gao Xiang
  1 sibling, 1 reply; 159+ messages in thread
From: David Sterba @ 2019-09-02 13:43 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Gao Xiang, Jan Kara, Dave Chinner, LKML,
	Miao Xie, devel, Stephen Rothwell, Darrick J . Wong,
	Linus Torvalds, Amir Goldstein, Alexander Viro, Jaegeuk Kim,
	Theodore Ts'o, Pavel Machek, David Sterba,
	Greg Kroah-Hartman, linux-fsdevel, Andrew Morton, linux-erofs

On Sun, Sep 01, 2019 at 05:34:00PM +0800, Gao Xiang wrote:
> > > +static int read_inode(struct inode *inode, void *data)
> > > +{
> > > +	struct erofs_vnode *vi = EROFS_V(inode);
> > > +	struct erofs_inode_v1 *v1 = data;
> > > +	const unsigned int advise = le16_to_cpu(v1->i_advise);
> > > +	erofs_blk_t nblks = 0;
> > > +
> > > +	vi->datamode = __inode_data_mapping(advise);
> > 
> > What is the deal with these magic underscores here and various
> > other similar helpers?
> 
> Fixed in
> https://lore.kernel.org/linux-fsdevel/20190901055130.30572-17-hsiangkao@aol.com/
> 
> underscores means 'internal' in my thought, it seems somewhat
> some common practice of Linux kernel, or some recent discussions
> about it?... I didn't notice these discussions...

I know about a few valid uses of the underscores:

* pattern where the __underscored version does not do locking, while the other
  does
* similarly for atomic and non-atomic version
* macro that needs to manipulate the argument name (like glue some
  prefix, so the macro does not have underscores and is supposed to be
  used instead of the function with underscores that needs the full name
  of a variable/constant/..
* underscore function takes a few more parameters to further tune the
  behaviour, but most users are fine with the defaults and that is
  provided as a function without underscores
* in case you have just one function of the kind, don't use the underscores

I can lookup examples if you're interested or if the brief description
is not sufficient. The list covers what I've seen and used, but the list
may be incomplete.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 05/24] erofs: add inode operations
  2019-09-02 13:43       ` David Sterba
@ 2019-09-02 13:55         ` Gao Xiang
  0 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-02 13:55 UTC (permalink / raw)
  To: dsterba
  Cc: Gao Xiang, Christoph Hellwig, Jan Kara, Dave Chinner, LKML,
	Miao Xie, devel, Stephen Rothwell, Darrick J . Wong,
	Linus Torvalds, Amir Goldstein, Alexander Viro, Jaegeuk Kim,
	Theodore Ts'o, Pavel Machek, Greg Kroah-Hartman,
	linux-fsdevel, Andrew Morton, linux-erofs

Hi David,

On Mon, Sep 02, 2019 at 03:43:29PM +0200, David Sterba wrote:
> On Sun, Sep 01, 2019 at 05:34:00PM +0800, Gao Xiang wrote:
> > > > +static int read_inode(struct inode *inode, void *data)
> > > > +{
> > > > +	struct erofs_vnode *vi = EROFS_V(inode);
> > > > +	struct erofs_inode_v1 *v1 = data;
> > > > +	const unsigned int advise = le16_to_cpu(v1->i_advise);
> > > > +	erofs_blk_t nblks = 0;
> > > > +
> > > > +	vi->datamode = __inode_data_mapping(advise);
> > > 
> > > What is the deal with these magic underscores here and various
> > > other similar helpers?
> > 
> > Fixed in
> > https://lore.kernel.org/linux-fsdevel/20190901055130.30572-17-hsiangkao@aol.com/
> > 
> > underscores means 'internal' in my thought, it seems somewhat
> > some common practice of Linux kernel, or some recent discussions
> > about it?... I didn't notice these discussions...
> 
> I know about a few valid uses of the underscores:
> 
> * pattern where the __underscored version does not do locking, while the other
>   does
> * similarly for atomic and non-atomic version
> * macro that needs to manipulate the argument name (like glue some
>   prefix, so the macro does not have underscores and is supposed to be
>   used instead of the function with underscores that needs the full name
>   of a variable/constant/..
> * underscore function takes a few more parameters to further tune the
>   behaviour, but most users are fine with the defaults and that is
>   provided as a function without underscores
> * in case you have just one function of the kind, don't use the underscores
> 
> I can lookup examples if you're interested or if the brief description
> is not sufficient. The list covers what I've seen and used, but the list
> may be incomplete.

Thanks, I learn a lot from the above. [thumb]

Thanks,
Gao Xiang


^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 01/24] erofs: add on-disk layout
  2019-09-02  8:43           ` Pavel Machek
@ 2019-09-02 14:07             ` David Sterba
  2019-09-03 11:27               ` Pavel Machek
  0 siblings, 1 reply; 159+ messages in thread
From: David Sterba @ 2019-09-02 14:07 UTC (permalink / raw)
  To: Pavel Machek
  Cc: dsterba, Joe Perches, Gao Xiang, Christoph Hellwig,
	Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Amir Goldstein,
	Darrick J . Wong, Dave Chinner, Jaegeuk Kim, Jan Kara,
	Linus Torvalds, linux-fsdevel, devel, LKML, linux-erofs, Chao Yu,
	Miao Xie, Li Guifu, Fang Wei

On Mon, Sep 02, 2019 at 10:43:03AM +0200, Pavel Machek wrote:
> > > > Rather than they didn't run "gdb" or "pahole" and change it by mistake.
> > > 
> > > I think Christoph is not right here.
> > > 
> > > Using external tools for validation is extra work
> > > when necessary for understanding the code.
> > 
> > The advantage of using the external tools that the information about
> > offsets is provably correct ...
> 
> No. gdb tells you what the actual offsets _are_.

Ok, reading your reply twice, I think we have different perspectives. I
don't trust the comments.

The tool I had in mind is pahole that parses dwarf information about the
structures, the same as gdb does. The actual value of the struct members
is the thing that needs to be investigated in memory dumps or disk image
dumps.

> > > The expected offset is somewhat valuable, but
> > > perhaps the form is a bit off given the visual
> > > run-in to the field types.
> > > 
> > > The extra work with this form is manipulating all
> > > the offsets whenever a structure change occurs.
> > 
> > ... while this is error prone.
> 
> While the comment tells you what they _should be_.

That's exactly the source of confusion and bugs. For me an acceptable
way of asserting that a value has certain offset is a build check, eg.
like

BUILD_BUG_ON(strct my_superblock, magic, 16);

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 00/21] erofs: patchset addressing Christoph's comments
  2019-09-02 12:46   ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Christoph Hellwig
@ 2019-09-02 14:24     ` Gao Xiang
  2019-09-02 15:23       ` Christoph Hellwig
  0 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-02 14:24 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Gao Xiang, Chao Yu, Greg Kroah-Hartman, linux-fsdevel, devel,
	linux-erofs, Chao Yu

Hi Christoph,

On Mon, Sep 02, 2019 at 05:46:45AM -0700, Christoph Hellwig wrote:
> On Sun, Sep 01, 2019 at 01:51:09PM +0800, Gao Xiang wrote:
> > Hi,
> > 
> > This patchset is based on the following patch by Pratik Shinde,
> > https://lore.kernel.org/linux-erofs/20190830095615.10995-1-pratikshinde320@gmail.com/
> > 
> > All patches addressing Christoph's comments on v6, which are trivial,
> > most deleted code are from erofs specific fault injection, which was
> > followed f2fs and previously discussed in earlier topic [1], but
> > let's follow what Christoph's said now.
> 
> I like where the cleanups are going.  But this is really just basic

For now, I think it will go to Greg's tree. Before that, I will do patchset
v2 to address all remaining comments...

> code quality stuff.  We're not addressing the issues with large amounts
> of functionality duplicating VFS helpers.

You means killing erofs_get_meta_page or avoid erofs_read_raw_page?

 - For killing erofs_get_meta_page, here is the current erofs_get_meta_page:

 35 struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr)
 36 {
 37         struct inode *const bd_inode = sb->s_bdev->bd_inode;
 38         struct address_space *const mapping = bd_inode->i_mapping;
 39         /* prefer retrying in the allocator to blindly looping below */
 40         const gfp_t gfp = mapping_gfp_constraint(mapping, ~__GFP_FS);
 41         struct page *page;
 42         int err;
 43
 44 repeat:
 45         page = find_or_create_page(mapping, blkaddr, gfp);
 46         if (!page)
 47                 return ERR_PTR(-ENOMEM);
 48
 49         DBG_BUGON(!PageLocked(page));
 50
 51         if (!PageUptodate(page)) {
 52                 struct bio *bio;
 53
 54                 bio = erofs_grab_bio(sb, REQ_OP_READ | REQ_META,
 55                                      blkaddr, 1, sb, erofs_readendio);
 56
 57                 if (bio_add_page(bio, page, PAGE_SIZE, 0) != PAGE_SIZE) {
 58                         err = -EFAULT;
 59                         goto err_out;
 60                 }
 61
 62                 submit_bio(bio);
 63                 lock_page(page);
 64
 65                 /* this page has been truncated by others */
 66                 if (page->mapping != mapping) {
 67                         unlock_page(page);
 68                         put_page(page);
 69                         goto repeat;
 70                 }
 71
 72                 /* more likely a read error */
 73                 if (!PageUptodate(page)) {
 74                         err = -EIO;
 75                         goto err_out;
 76                 }
 77         }
 78         return page;
 79
 80 err_out:
 81         unlock_page(page);
 82         put_page(page);
 83         return ERR_PTR(err);
 84 }

I think it is simple enough. read_cache_page need write a similar
filler, or read_cache_page_gfp will call .readpage, and then
introduce buffer_heads, that is what I'd like to avoid now (no need these
bd_inode buffer_heads in memory...)

 - For erofs_read_raw_page, it can be avoided after iomap tail-end packing
   feature is done... If we remove it now, it will make EROFS broken.
   It is no urgent and Chao will focus on iomap tail-end packing feature.

Thanks,
Gao Xiang


^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 03/24] erofs: add super block operations
  2019-09-02 12:51       ` Christoph Hellwig
@ 2019-09-02 14:43         ` Gao Xiang
  2019-09-02 15:19           ` Christoph Hellwig
  0 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-02 14:43 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Gao Xiang, Jan Kara, Chao Yu, Dave Chinner, LKML, Miao Xie,
	devel, Stephen Rothwell, Darrick J . Wong, Linus Torvalds,
	Amir Goldstein, Alexander Viro, Jaegeuk Kim, Theodore Ts'o,
	Pavel Machek, David Sterba, Li Guifu, Fang Wei,
	Greg Kroah-Hartman, linux-fsdevel, Andrew Morton, linux-erofs

Hi Christoph,

On Mon, Sep 02, 2019 at 05:51:09AM -0700, Christoph Hellwig wrote:
> On Sun, Sep 01, 2019 at 04:54:55PM +0800, Gao Xiang wrote:
> > No modification at this... (some comments already right here...)
> 
> >  20 /* 128-byte erofs on-disk super block */
> >  21 struct erofs_super_block {
> > ...
> >  24         __le32 features;        /* (aka. feature_compat) */
> > ...
> >  38         __le32 requirements;    /* (aka. feature_incompat) */
> > ...
> >  41 };
> 
> This is only cosmetic, why not stick to feature_compat and
> feature_incompat?

Okay, will fix. (however, in my mind, I'm some confused why
"features" could be incompatible...)

> 
> > > > +	bh = sb_bread(sb, 0);
> > > 
> > > Is there any good reasons to use buffer heads like this in new code
> > > vs directly using bios?
> > 
> > As you said, I want it in the page cache.
> > 
> > The reason "why not use read_mapping_page or similar?" is simply
> > read_mapping_page -> .readpage -> (for bdev inode) block_read_full_page
> >  -> create_page_buffers anyway...
> > 
> > sb_bread haven't obsoleted... It has similar function though...
> 
> With the different that it keeps you isolated from the buffer_head
> internals.  This seems to be your only direct use of buffer heads,
> which while not deprecated are a bit of an ugly step child.  So if
> you can easily avoid creating a buffer_head dependency in a new
> filesystem I think you should avoid it.

OK, let's use read_mapping_page instead.

> 
> > > > +	sbi->build_time = le64_to_cpu(layout->build_time);
> > > > +	sbi->build_time_nsec = le32_to_cpu(layout->build_time_nsec);
> > > > +
> > > > +	memcpy(&sb->s_uuid, layout->uuid, sizeof(layout->uuid));
> > > > +	memcpy(sbi->volume_name, layout->volume_name,
> > > > +	       sizeof(layout->volume_name));
> > > 
> > > s_uuid should preferably be a uuid_t (assuming it is a real BE uuid,
> > > if it is le it should be a guid_t).
> > 
> > For this case, I have no idea how to deal with...
> > I have little knowledge about this uuid stuff, so I just copied
> > from f2fs... (Could be no urgent of this field...)
> 
> Who fills out this field in the on-disk format and how?

mkfs.erofs, but this field leaves 0 for now. Is that reasonable?
(using libuuid can generate it easily...)

> 
> > The background is Al's comments in erofs v2....
> > (which simplify erofs_fill_super logic)
> > https://lore.kernel.org/r/20190720224955.GD17978@ZenIV.linux.org.uk/
> > 
> > with a specific notation...
> > https://lore.kernel.org/r/20190721040547.GF17978@ZenIV.linux.org.uk/
> > 
> > "
> > > OTOH, for the case of NULL ->s_root ->put_super() won't be called
> > > at all, so in that case you need it directly in ->kill_sb().
> > "
> 
> Yes.  Although none of that is relevant for this initial version,
> just after more features are added.

This patch uses it actually... since no failure path in erofs_fill_super()
and s_root will be filled nearly at the end of the function...

Thanks,
Gao Xiang




^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 03/24] erofs: add super block operations
  2019-09-02 14:43         ` Gao Xiang
@ 2019-09-02 15:19           ` Christoph Hellwig
  2019-09-02 15:24             ` Gao Xiang
  0 siblings, 1 reply; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 15:19 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Gao Xiang, Jan Kara, Chao Yu, Dave Chinner,
	LKML, Miao Xie, devel, Stephen Rothwell, Darrick J . Wong,
	Linus Torvalds, Amir Goldstein, Alexander Viro, Jaegeuk Kim,
	Theodore Ts'o, Pavel Machek, David Sterba, Li Guifu,
	Fang Wei, Greg Kroah-Hartman, linux-fsdevel, Andrew Morton,
	linux-erofs

On Mon, Sep 02, 2019 at 10:43:04PM +0800, Gao Xiang wrote:
> Hi Christoph,
> > > ...
> > >  24         __le32 features;        /* (aka. feature_compat) */
> > > ...
> > >  38         __le32 requirements;    /* (aka. feature_incompat) */
> > > ...
> > >  41 };
> > 
> > This is only cosmetic, why not stick to feature_compat and
> > feature_incompat?
> 
> Okay, will fix. (however, in my mind, I'm some confused why
> "features" could be incompatible...)

The feature is incompatible if it requires changes to the driver.
An easy to understand historic example is that ext3 originally did not
have the file types in the directory entry.  Adding them means old
file system drivers can not read a file system with this new feature,
so an incompat flag has to be added.

> > > > > +	memcpy(&sb->s_uuid, layout->uuid, sizeof(layout->uuid));
> > > > > +	memcpy(sbi->volume_name, layout->volume_name,
> > > > > +	       sizeof(layout->volume_name));
> > > > 
> > > > s_uuid should preferably be a uuid_t (assuming it is a real BE uuid,
> > > > if it is le it should be a guid_t).
> > > 
> > > For this case, I have no idea how to deal with...
> > > I have little knowledge about this uuid stuff, so I just copied
> > > from f2fs... (Could be no urgent of this field...)
> > 
> > Who fills out this field in the on-disk format and how?
> 
> mkfs.erofs, but this field leaves 0 for now. Is that reasonable?
> (using libuuid can generate it easily...)

If the filed is always zero for now please don't fill it out.  If you
decide it is worth adding the uuid eventually please add a compat
feature flag that you have a valid uuid and only fill out the field
if the file system actualy has a valid uuid.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 00/21] erofs: patchset addressing Christoph's comments
  2019-09-02 14:24     ` Gao Xiang
@ 2019-09-02 15:23       ` Christoph Hellwig
  2019-09-02 15:50         ` Gao Xiang
  0 siblings, 1 reply; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-02 15:23 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Gao Xiang, Chao Yu, Greg Kroah-Hartman,
	linux-fsdevel, devel, linux-erofs, Chao Yu

On Mon, Sep 02, 2019 at 10:24:52PM +0800, Gao Xiang wrote:
> > code quality stuff.  We're not addressing the issues with large amounts
> > of functionality duplicating VFS helpers.
> 
> You means killing erofs_get_meta_page or avoid erofs_read_raw_page?
> 
>  - For killing erofs_get_meta_page, here is the current erofs_get_meta_page:

> I think it is simple enough. read_cache_page need write a similar
> filler, or read_cache_page_gfp will call .readpage, and then
> introduce buffer_heads, that is what I'd like to avoid now (no need these
> bd_inode buffer_heads in memory...)

If using read_cache_page_gfp and ->readpage works, please do.  The
fact that the block device inode uses buffer heads is an implementation
detail that might not last very long and should be invisible to you.
It also means you can get rid of a lot of code that you don't have
to maintain and others don't have to update for global API changes.

>  - For erofs_read_raw_page, it can be avoided after iomap tail-end packing
>    feature is done... If we remove it now, it will make EROFS broken.
>    It is no urgent and Chao will focus on iomap tail-end packing feature.

Ok.  I wish we would have just sorted this out beforehand, which we
could have trivially done without all that staging mess.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 03/24] erofs: add super block operations
  2019-09-02 15:19           ` Christoph Hellwig
@ 2019-09-02 15:24             ` Gao Xiang
  0 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-02 15:24 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Gao Xiang, Jan Kara, Chao Yu, Dave Chinner, LKML, Miao Xie,
	devel, Stephen Rothwell, Darrick J . Wong, Linus Torvalds,
	Amir Goldstein, Alexander Viro, Jaegeuk Kim, Theodore Ts'o,
	Pavel Machek, David Sterba, Li Guifu, Fang Wei,
	Greg Kroah-Hartman, linux-fsdevel, Andrew Morton, linux-erofs

Hi Christoph,

On Mon, Sep 02, 2019 at 08:19:10AM -0700, Christoph Hellwig wrote:
> On Mon, Sep 02, 2019 at 10:43:04PM +0800, Gao Xiang wrote:
> > Hi Christoph,
> > > > ...
> > > >  24         __le32 features;        /* (aka. feature_compat) */
> > > > ...
> > > >  38         __le32 requirements;    /* (aka. feature_incompat) */
> > > > ...
> > > >  41 };
> > > 
> > > This is only cosmetic, why not stick to feature_compat and
> > > feature_incompat?
> > 
> > Okay, will fix. (however, in my mind, I'm some confused why
> > "features" could be incompatible...)
> 
> The feature is incompatible if it requires changes to the driver.
> An easy to understand historic example is that ext3 originally did not
> have the file types in the directory entry.  Adding them means old
> file system drivers can not read a file system with this new feature,
> so an incompat flag has to be added.

Got it.

> 
> > > > > > +	memcpy(&sb->s_uuid, layout->uuid, sizeof(layout->uuid));
> > > > > > +	memcpy(sbi->volume_name, layout->volume_name,
> > > > > > +	       sizeof(layout->volume_name));
> > > > > 
> > > > > s_uuid should preferably be a uuid_t (assuming it is a real BE uuid,
> > > > > if it is le it should be a guid_t).
> > > > 
> > > > For this case, I have no idea how to deal with...
> > > > I have little knowledge about this uuid stuff, so I just copied
> > > > from f2fs... (Could be no urgent of this field...)
> > > 
> > > Who fills out this field in the on-disk format and how?
> > 
> > mkfs.erofs, but this field leaves 0 for now. Is that reasonable?
> > (using libuuid can generate it easily...)
> 
> If the filed is always zero for now please don't fill it out.  If you
> decide it is worth adding the uuid eventually please add a compat
> feature flag that you have a valid uuid and only fill out the field
> if the file system actualy has a valid uuid.

Okay. Will do that then (as a note here).

Thanks,
Gao Xiang


^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 00/21] erofs: patchset addressing Christoph's comments
  2019-09-02 15:23       ` Christoph Hellwig
@ 2019-09-02 15:50         ` Gao Xiang
  2019-09-03  6:58           ` Christoph Hellwig
  0 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-02 15:50 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Gao Xiang, Chao Yu, Greg Kroah-Hartman, linux-fsdevel, devel,
	linux-erofs, Chao Yu

Hi Christoph,

On Mon, Sep 02, 2019 at 08:23:23AM -0700, Christoph Hellwig wrote:
> On Mon, Sep 02, 2019 at 10:24:52PM +0800, Gao Xiang wrote:
> > > code quality stuff.  We're not addressing the issues with large amounts
> > > of functionality duplicating VFS helpers.
> > 
> > You means killing erofs_get_meta_page or avoid erofs_read_raw_page?
> > 
> >  - For killing erofs_get_meta_page, here is the current erofs_get_meta_page:
> 
> > I think it is simple enough. read_cache_page need write a similar
> > filler, or read_cache_page_gfp will call .readpage, and then
> > introduce buffer_heads, that is what I'd like to avoid now (no need these
> > bd_inode buffer_heads in memory...)
> 
> If using read_cache_page_gfp and ->readpage works, please do.  The
> fact that the block device inode uses buffer heads is an implementation
> detail that might not last very long and should be invisible to you.
> It also means you can get rid of a lot of code that you don't have
> to maintain and others don't have to update for global API changes.

I care about those useless buffer_heads in memory for our products...

Since we are nobh filesystem (a little request, could I use it
after buffer_heads are fully avoided, I have no idea why I need
those buffer_heads in memory.... But I think bd_inode is good
for caching metadata...)

> 
> >  - For erofs_read_raw_page, it can be avoided after iomap tail-end packing
> >    feature is done... If we remove it now, it will make EROFS broken.
> >    It is no urgent and Chao will focus on iomap tail-end packing feature.
> 
> Ok.  I wish we would have just sorted this out beforehand, which we
> could have trivially done without all that staging mess.

Firstly, I'd like to introduce EROFS as a self-contained
filesystem to introduce new fixed-sized output compression
to upstream and promote it...

And then we can do many improvements for EROFS in parallel...
(if we introduce EROFS and touch many core modules like
iomap, mm readahead code or modify LZ4 code at once...
It could be more careful... Let's improve it step-by-step...
We are a dedicated team if the Linux community needs us,
we will still here... It will be actively maintained.)

Thanks,
Gao Xiang



^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 00/21] erofs: patchset addressing Christoph's comments
  2019-09-02 15:50         ` Gao Xiang
@ 2019-09-03  6:58           ` Christoph Hellwig
  2019-09-03  8:17             ` Gao Xiang
  0 siblings, 1 reply; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-03  6:58 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Gao Xiang, Chao Yu, Greg Kroah-Hartman,
	linux-fsdevel, devel, linux-erofs, Chao Yu

On Mon, Sep 02, 2019 at 11:50:38PM +0800, Gao Xiang wrote:
> > > You means killing erofs_get_meta_page or avoid erofs_read_raw_page?
> > > 
> > >  - For killing erofs_get_meta_page, here is the current erofs_get_meta_page:
> > 
> > > I think it is simple enough. read_cache_page need write a similar
> > > filler, or read_cache_page_gfp will call .readpage, and then
> > > introduce buffer_heads, that is what I'd like to avoid now (no need these
> > > bd_inode buffer_heads in memory...)
> > 
> > If using read_cache_page_gfp and ->readpage works, please do.  The
> > fact that the block device inode uses buffer heads is an implementation
> > detail that might not last very long and should be invisible to you.
> > It also means you can get rid of a lot of code that you don't have
> > to maintain and others don't have to update for global API changes.
> 
> I care about those useless buffer_heads in memory for our products...
> 
> Since we are nobh filesystem (a little request, could I use it
> after buffer_heads are fully avoided, I have no idea why I need
> those buffer_heads in memory.... But I think bd_inode is good
> for caching metadata...)

Then please use read_cache_page with iomap_readpage(s), and write
comment explaining why your are not using read_cache_page_gfp.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 00/21] erofs: patchset addressing Christoph's comments
  2019-09-03  6:58           ` Christoph Hellwig
@ 2019-09-03  8:17             ` Gao Xiang
  2019-09-03 15:37               ` Christoph Hellwig
  0 siblings, 1 reply; 159+ messages in thread
From: Gao Xiang @ 2019-09-03  8:17 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Gao Xiang, Chao Yu, Greg Kroah-Hartman, linux-fsdevel, devel,
	linux-erofs, Chao Yu

Hi Christoph,

On Mon, Sep 02, 2019 at 11:58:03PM -0700, Christoph Hellwig wrote:
> On Mon, Sep 02, 2019 at 11:50:38PM +0800, Gao Xiang wrote:
> > > > You means killing erofs_get_meta_page or avoid erofs_read_raw_page?
> > > > 
> > > >  - For killing erofs_get_meta_page, here is the current erofs_get_meta_page:
> > > 
> > > > I think it is simple enough. read_cache_page need write a similar
> > > > filler, or read_cache_page_gfp will call .readpage, and then
> > > > introduce buffer_heads, that is what I'd like to avoid now (no need these
> > > > bd_inode buffer_heads in memory...)
> > > 
> > > If using read_cache_page_gfp and ->readpage works, please do.  The
> > > fact that the block device inode uses buffer heads is an implementation
> > > detail that might not last very long and should be invisible to you.
> > > It also means you can get rid of a lot of code that you don't have
> > > to maintain and others don't have to update for global API changes.
> > 
> > I care about those useless buffer_heads in memory for our products...
> > 
> > Since we are nobh filesystem (a little request, could I use it
> > after buffer_heads are fully avoided, I have no idea why I need
> > those buffer_heads in memory.... But I think bd_inode is good
> > for caching metadata...)
> 
> Then please use read_cache_page with iomap_readpage(s), and write
> comment explaining why your are not using read_cache_page_gfp.

I implement a prelimitary version, but I have no idea it is a really
cleanup for now.

From 001e3e64c81e4ced0d22b147e6abf90060e704b5 Mon Sep 17 00:00:00 2001
From: Gao Xiang <gaoxiang25@huawei.com>
Date: Tue, 3 Sep 2019 16:13:00 +0800
Subject: [PATCH] erofs: use iomap_readpage for erofs_get_meta_page

Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/Kconfig |  1 +
 fs/erofs/data.c  | 91 ++++++++++++++++++++++++++----------------------
 2 files changed, 51 insertions(+), 41 deletions(-)

diff --git a/fs/erofs/Kconfig b/fs/erofs/Kconfig
index 9d634d3a1845..c9eeb0bf4737 100644
--- a/fs/erofs/Kconfig
+++ b/fs/erofs/Kconfig
@@ -3,6 +3,7 @@
 config EROFS_FS
 	tristate "EROFS filesystem support"
 	depends on BLOCK
+	select FS_IOMAP
 	help
 	  EROFS (Enhanced Read-Only File System) is a lightweight
 	  read-only file system with modern designs (eg. page-sized
diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index 3881c0689134..34c6e05fab71 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -5,6 +5,9 @@
  * Created by Gao Xiang <gaoxiang25@huawei.com>
  */
 #include "internal.h"
+#include <linux/iomap.h>
+#include <linux/mpage.h>
+#include <linux/sched/mm.h>
 #include <linux/prefetch.h>
 
 #include <trace/events/erofs.h>
@@ -51,54 +54,60 @@ static struct bio *erofs_grab_raw_bio(struct super_block *sb,
 	return bio;
 }
 
-struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr)
+static int erofs_meta_iomap_begin(struct inode *inode, loff_t pos,
+				  loff_t length, unsigned int flags,
+				  struct iomap *iomap)
 {
-	struct inode *const bd_inode = sb->s_bdev->bd_inode;
-	struct address_space *const mapping = bd_inode->i_mapping;
-	/* prefer retrying in the allocator to blindly looping below */
-	const gfp_t gfp = mapping_gfp_constraint(mapping, ~__GFP_FS);
-	struct page *page;
-	int err;
-
-repeat:
-	page = find_or_create_page(mapping, blkaddr, gfp);
-	if (!page)
-		return ERR_PTR(-ENOMEM);
-
-	DBG_BUGON(!PageLocked(page));
-
-	if (!PageUptodate(page)) {
-		struct bio *bio;
+	const unsigned int blkbits = inode->i_blkbits;
+
+	iomap->flags = 0;
+	iomap->bdev = I_BDEV(inode);
+	iomap->offset = round_down(pos, 1 << blkbits);
+	iomap->addr = iomap->offset;
+	iomap->length = round_up(length, 1 << blkbits);
+	iomap->type = IOMAP_MAPPED;
+	return 0;
+}
 
-		bio = erofs_grab_raw_bio(sb, blkaddr, 1, true);
+static const struct iomap_ops erofs_meta_iomap_ops = {
+	.iomap_begin = erofs_meta_iomap_begin,
+};
 
-		if (bio_add_page(bio, page, PAGE_SIZE, 0) != PAGE_SIZE) {
-			err = -EFAULT;
-			goto err_out;
-		}
+static int
+erofs_meta_get_block(struct inode *inode, sector_t iblock,
+		     struct buffer_head *bh, int create)
+{
+	bh->b_bdev = I_BDEV(inode);
+	bh->b_blocknr = iblock;
+	set_buffer_mapped(bh);
+	return 0;
+}
 
-		submit_bio(bio);
-		lock_page(page);
+static int erofs_read_meta_page(void *file, struct page *page)
+{
+	/* in case of getting some pages with buffer_heads */
+	if (i_blocksize(page->mapping->host) == PAGE_SIZE &&
+	    !page_has_buffers(page))
+		return iomap_readpage(page, &erofs_meta_iomap_ops);
+
+	/*
+	 * cannot use blkdev_readpage or blkdev_get_block directly
+	 * since static in block_dev.c
+	 */
+	return mpage_readpage(page, erofs_meta_get_block);
+}
 
-		/* this page has been truncated by others */
-		if (page->mapping != mapping) {
-			unlock_page(page);
-			put_page(page);
-			goto repeat;
-		}
+struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr)
+{
+	struct inode *const bd_inode = sb->s_bdev->bd_inode;
+	struct address_space *const mapping = bd_inode->i_mapping;
+	unsigned int nofs_flag;
+	struct page *page;
 
-		/* more likely a read error */
-		if (!PageUptodate(page)) {
-			err = -EIO;
-			goto err_out;
-		}
-	}
+	nofs_flag = memalloc_nofs_save();
+	page = read_cache_page(mapping, blkaddr, erofs_read_meta_page, NULL);
+	memalloc_nofs_restore(nofs_flag);
 	return page;
-
-err_out:
-	unlock_page(page);
-	put_page(page);
-	return ERR_PTR(err);
 }
 
 static int erofs_map_blocks_flatmode(struct inode *inode,
-- 
2.17.1



^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH v6 01/24] erofs: add on-disk layout
  2019-09-02 14:07             ` David Sterba
@ 2019-09-03 11:27               ` Pavel Machek
  0 siblings, 0 replies; 159+ messages in thread
From: Pavel Machek @ 2019-09-03 11:27 UTC (permalink / raw)
  To: dsterba, Pavel Machek, Joe Perches, Gao Xiang, Christoph Hellwig,
	Alexander Viro, Greg Kroah-Hartman, Andrew Morton,
	Stephen Rothwell, Theodore Ts'o, Amir Goldstein,
	Darrick J . Wong, Dave Chinner, Jaegeuk Kim, Jan Kara,
	Linus Torvalds, linux-fsdevel, devel, LKML, linux-erofs, Chao Yu,
	Miao Xie, Li Guifu, Fang Wei

[-- Attachment #1: Type: text/plain, Size: 1272 bytes --]

Hi!

> > No. gdb tells you what the actual offsets _are_.
> 
> Ok, reading your reply twice, I think we have different perspectives. I
> don't trust the comments.
> 
> The tool I had in mind is pahole that parses dwarf information about the
> structures, the same as gdb does. The actual value of the struct members
> is the thing that needs to be investigated in memory dumps or disk image
> dumps.
> 
> > > > The expected offset is somewhat valuable, but
> > > > perhaps the form is a bit off given the visual
> > > > run-in to the field types.
> > > > 
> > > > The extra work with this form is manipulating all
> > > > the offsets whenever a structure change occurs.
> > > 
> > > ... while this is error prone.
> > 
> > While the comment tells you what they _should be_.
> 
> That's exactly the source of confusion and bugs. For me an acceptable
> way of asserting that a value has certain offset is a build check, eg.
> like
> 
> BUILD_BUG_ON(strct my_superblock, magic, 16);

Yes, that would work, too. As would documentation file with the disk
structures.

Best regards,
								Pavel
-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 181 bytes --]

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 00/21] erofs: patchset addressing Christoph's comments
  2019-09-03  8:17             ` Gao Xiang
@ 2019-09-03 15:37               ` Christoph Hellwig
  2019-09-03 15:43                 ` Gao Xiang
  0 siblings, 1 reply; 159+ messages in thread
From: Christoph Hellwig @ 2019-09-03 15:37 UTC (permalink / raw)
  To: Gao Xiang
  Cc: Christoph Hellwig, Gao Xiang, Chao Yu, Greg Kroah-Hartman,
	linux-fsdevel, devel, linux-erofs, Chao Yu

On Tue, Sep 03, 2019 at 04:17:49PM +0800, Gao Xiang wrote:
> I implement a prelimitary version, but I have no idea it is a really
> cleanup for now.

The fact that this has to guess the block device address_space
implementation is indeed pretty ugly.  I'd much prefer to just use
read_cache_page_gfp, and live with the fact that this allocates
bufferheads behind you for now.  I'll try to speed up my attempts to
get rid of the buffer heads on the block device mapping instead.

^ permalink raw reply	[flat|nested] 159+ messages in thread

* Re: [PATCH 00/21] erofs: patchset addressing Christoph's comments
  2019-09-03 15:37               ` Christoph Hellwig
@ 2019-09-03 15:43                 ` Gao Xiang
  0 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-03 15:43 UTC (permalink / raw)
  To: Christoph Hellwig
  Cc: Gao Xiang, Gao Xiang, Chao Yu, Greg Kroah-Hartman, linux-fsdevel,
	devel, linux-erofs, Chao Yu

Hi Christoph,

On Tue, Sep 03, 2019 at 08:37:04AM -0700, Christoph Hellwig wrote:
> On Tue, Sep 03, 2019 at 04:17:49PM +0800, Gao Xiang wrote:
> > I implement a prelimitary version, but I have no idea it is a really
> > cleanup for now.
> 
> The fact that this has to guess the block device address_space
> implementation is indeed pretty ugly.  I'd much prefer to just use
> read_cache_page_gfp, and live with the fact that this allocates
> bufferheads behind you for now.  I'll try to speed up my attempts to
> get rid of the buffer heads on the block device mapping instead.

Fully agree with your point. Let me use read_cache_page_gfp
instead for now, hoping block device quickly avoiding from
buffer_heads...

Thanks,
Gao Xiang


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v2 00/25] erofs: patchset addressing Christoph's comments
  2019-09-01  5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang
                     ` (21 preceding siblings ...)
  2019-09-02 12:46   ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Christoph Hellwig
@ 2019-09-04  2:08   ` " Gao Xiang
  2019-09-04  2:08     ` [PATCH v2 01/25] erofs: remove all the byte offset comments Gao Xiang
                       ` (26 more replies)
  22 siblings, 27 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-04  2:08 UTC (permalink / raw)
  To: Chao Yu, Greg Kroah-Hartman, Christoph Hellwig, devel
  Cc: linux-fsdevel, linux-erofs, Chao Yu, Miao Xie, Gao Xiang

Hi,

This patchset is based on the following patch by Pratik Shinde,
https://lore.kernel.org/linux-erofs/20190830095615.10995-1-pratikshinde320@gmail.com/

All patches addressing Christoph's comments on v6, which are trivial,
most deleted code are from erofs specific fault injection, which was
followed f2fs and previously discussed in earlier topic [1], but
let's follow what Christoph's said now.

Comments and suggestions are welcome...

[1] https://lore.kernel.org/r/1eed1e6b-f95e-aa8e-c3e7-e9870401ee23@kernel.org/

changes since v1:
 - leave some comments near the numbers to indicate where they are stored;
 - avoid a u8 cast;
 - use erofs_{err,info,dbg} and print sb->s_id as a prefix before
   the actual message;
 - add a on-disk title in erofs_fs.h
 - use feature_{compat,incompat} rather than features and requirements;
 - suggestions on erofs_grab_bio:
   https://lore.kernel.org/r/20190902122016.GL15931@infradead.org/
 - use compact/extended instead of erofs_inode_v1/v2 and
   i_format instead of i_advise;
 - avoid chained if/else if/else if statements in erofs_read_inode;
 - avoid erofs_vmap/vunmap wrappers;
 - use read_cache_page_gfp for erofs_get_meta_page;

Gao Xiang (25):
  erofs: remove all the byte offset comments
  erofs: on-disk format should have explicitly assigned numbers
  erofs: some macros are much more readable as a function
  erofs: kill __packed for on-disk structures
  erofs: update erofs_inode_is_data_compressed helper
  erofs: use feature_incompat rather than requirements
  erofs: better naming for erofs inode related stuffs
  erofs: kill erofs_{init,exit}_inode_cache
  erofs: use erofs_inode naming
  erofs: update erofs_fs.h comments
  erofs: update comments in inode.c
  erofs: better erofs symlink stuffs
  erofs: use dsb instead of layout for ondisk super_block
  erofs: kill verbose debug info in erofs_fill_super
  erofs: localize erofs_grab_bio()
  erofs: kill prio and nofail of erofs_get_meta_page()
  erofs: kill __submit_bio()
  erofs: add "erofs_" prefix for common and short functions
  erofs: kill all erofs specific fault injection
  erofs: kill use_vmap module parameter
  erofs: save one level of indentation
  erofs: rename errln/infoln/debugln to erofs_{err,info,dbg}
  erofs: use read_mapping_page instead of sb_bread
  erofs: always use iget5_locked
  erofs: use read_cache_page_gfp for erofs_get_meta_page

 Documentation/filesystems/erofs.txt |   9 -
 fs/erofs/Kconfig                    |   7 -
 fs/erofs/data.c                     | 118 +++--------
 fs/erofs/decompressor.c             |  76 +++----
 fs/erofs/dir.c                      |  17 +-
 fs/erofs/erofs_fs.h                 | 197 +++++++++---------
 fs/erofs/inode.c                    | 297 ++++++++++++++--------------
 fs/erofs/internal.h                 | 192 ++++--------------
 fs/erofs/namei.c                    |  21 +-
 fs/erofs/super.c                    | 282 +++++++++++---------------
 fs/erofs/xattr.c                    |  41 ++--
 fs/erofs/xattr.h                    |   4 +-
 fs/erofs/zdata.c                    |  63 +++---
 fs/erofs/zdata.h                    |   2 +-
 fs/erofs/zmap.c                     |  73 +++----
 include/trace/events/erofs.h        |  14 +-
 16 files changed, 578 insertions(+), 835 deletions(-)

-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v2 01/25] erofs: remove all the byte offset comments
  2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
@ 2019-09-04  2:08     ` Gao Xiang
  2019-09-04  2:08     ` [PATCH v2 02/25] erofs: on-disk format should have explicitly assigned numbers Gao Xiang
                       ` (25 subsequent siblings)
  26 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-04  2:08 UTC (permalink / raw)
  To: Chao Yu, Greg Kroah-Hartman, Christoph Hellwig, devel
  Cc: linux-fsdevel, linux-erofs, Chao Yu, Miao Xie, Gao Xiang

As Christoph suggested [1], "Please remove all the byte offset comments.
that is something that can easily be checked with gdb or pahole."

[1] https://lore.kernel.org/r/20190829095954.GB20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/erofs_fs.h | 105 +++++++++++++++++++++++---------------------
 1 file changed, 54 insertions(+), 51 deletions(-)

diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
index afa7d45ca958..49335fff9d65 100644
--- a/fs/erofs/erofs_fs.h
+++ b/fs/erofs/erofs_fs.h
@@ -17,27 +17,28 @@
 #define EROFS_REQUIREMENT_LZ4_0PADDING	0x00000001
 #define EROFS_ALL_REQUIREMENTS		EROFS_REQUIREMENT_LZ4_0PADDING
 
+/* 128-byte erofs on-disk super block */
 struct erofs_super_block {
-/*  0 */__le32 magic;           /* in the little endian */
-/*  4 */__le32 checksum;        /* crc32c(super_block) */
-/*  8 */__le32 features;        /* (aka. feature_compat) */
-/* 12 */__u8 blkszbits;         /* support block_size == PAGE_SIZE only */
-/* 13 */__u8 reserved;
-
-/* 14 */__le16 root_nid;
-/* 16 */__le64 inos;            /* total valid ino # (== f_files - f_favail) */
-
-/* 24 */__le64 build_time;      /* inode v1 time derivation */
-/* 32 */__le32 build_time_nsec;
-/* 36 */__le32 blocks;          /* used for statfs */
-/* 40 */__le32 meta_blkaddr;
-/* 44 */__le32 xattr_blkaddr;
-/* 48 */__u8 uuid[16];          /* 128-bit uuid for volume */
-/* 64 */__u8 volume_name[16];   /* volume name */
-/* 80 */__le32 requirements;    /* (aka. feature_incompat) */
-
-/* 84 */__u8 reserved2[44];
-} __packed;                     /* 128 bytes */
+	__le32 magic;           /* file system magic number */
+	__le32 checksum;        /* crc32c(super_block) */
+	__le32 features;        /* (aka. feature_compat) */
+	__u8 blkszbits;         /* support block_size == PAGE_SIZE only */
+	__u8 reserved;
+
+	__le16 root_nid;	/* nid of root directory */
+	__le64 inos;            /* total valid ino # (== f_files - f_favail) */
+
+	__le64 build_time;      /* inode v1 time derivation */
+	__le32 build_time_nsec;	/* inode v1 time derivation in nano scale */
+	__le32 blocks;          /* used for statfs */
+	__le32 meta_blkaddr;	/* start block address of metadata area */
+	__le32 xattr_blkaddr;	/* start block address of shared xattr area */
+	__u8 uuid[16];          /* 128-bit uuid for volume */
+	__u8 volume_name[16];   /* volume name */
+	__le32 requirements;    /* (aka. feature_incompat) */
+
+	__u8 reserved2[44];
+} __packed;
 
 /*
  * erofs inode data mapping:
@@ -73,16 +74,17 @@ static inline bool erofs_inode_is_data_compressed(unsigned int datamode)
 #define EROFS_I_VERSION_BIT             0
 #define EROFS_I_DATA_MAPPING_BIT        1
 
+/* 32-byte reduced form of an ondisk inode */
 struct erofs_inode_v1 {
-/*  0 */__le16 i_advise;
+	__le16 i_advise;	/* inode hints */
 
 /* 1 header + n-1 * 4 bytes inline xattr to keep continuity */
-/*  2 */__le16 i_xattr_icount;
-/*  4 */__le16 i_mode;
-/*  6 */__le16 i_nlink;
-/*  8 */__le32 i_size;
-/* 12 */__le32 i_reserved;
-/* 16 */union {
+	__le16 i_xattr_icount;
+	__le16 i_mode;
+	__le16 i_nlink;
+	__le32 i_size;
+	__le32 i_reserved;
+	union {
 		/* file total compressed blocks for data mapping 1 */
 		__le32 compressed_blocks;
 		__le32 raw_blkaddr;
@@ -90,10 +92,10 @@ struct erofs_inode_v1 {
 		/* for device files, used to indicate old/new device # */
 		__le32 rdev;
 	} i_u __packed;
-/* 20 */__le32 i_ino;           /* only used for 32-bit stat compatibility */
-/* 24 */__le16 i_uid;
-/* 26 */__le16 i_gid;
-/* 28 */__le32 i_reserved2;
+	__le32 i_ino;           /* only used for 32-bit stat compatibility */
+	__le16 i_uid;
+	__le16 i_gid;
+	__le32 i_reserved2;
 } __packed;
 
 /* 32 bytes on-disk inode */
@@ -101,15 +103,16 @@ struct erofs_inode_v1 {
 /* 64 bytes on-disk inode */
 #define EROFS_INODE_LAYOUT_V2   1
 
+/* 64-byte complete form of an ondisk inode */
 struct erofs_inode_v2 {
-/*  0 */__le16 i_advise;
+	__le16 i_advise;	/* inode hints */
 
 /* 1 header + n-1 * 4 bytes inline xattr to keep continuity */
-/*  2 */__le16 i_xattr_icount;
-/*  4 */__le16 i_mode;
-/*  6 */__le16 i_reserved;
-/*  8 */__le64 i_size;
-/* 16 */union {
+	__le16 i_xattr_icount;
+	__le16 i_mode;
+	__le16 i_reserved;
+	__le64 i_size;
+	union {
 		/* file total compressed blocks for data mapping 1 */
 		__le32 compressed_blocks;
 		__le32 raw_blkaddr;
@@ -119,15 +122,15 @@ struct erofs_inode_v2 {
 	} i_u __packed;
 
 	/* only used for 32-bit stat compatibility */
-/* 20 */__le32 i_ino;
-
-/* 24 */__le32 i_uid;
-/* 28 */__le32 i_gid;
-/* 32 */__le64 i_ctime;
-/* 40 */__le32 i_ctime_nsec;
-/* 44 */__le32 i_nlink;
-/* 48 */__u8   i_reserved2[16];
-} __packed;                     /* 64 bytes */
+	__le32 i_ino;
+
+	__le32 i_uid;
+	__le32 i_gid;
+	__le64 i_ctime;
+	__le32 i_ctime_nsec;
+	__le32 i_nlink;
+	__u8   i_reserved2[16];
+} __packed;
 
 #define EROFS_MAX_SHARED_XATTRS         (128)
 /* h_shared_count between 129 ... 255 are special # */
@@ -264,7 +267,7 @@ struct z_erofs_vle_decompressed_index {
 		 * [1] - pointing to the tail cluster
 		 */
 		__le16 delta[2];
-	} di_u __packed;		/* 8 bytes */
+	} di_u __packed;
 } __packed;
 
 #define Z_EROFS_VLE_LEGACY_INDEX_ALIGN(size) \
@@ -273,10 +276,10 @@ struct z_erofs_vle_decompressed_index {
 
 /* dirent sorts in alphabet order, thus we can do binary search */
 struct erofs_dirent {
-	__le64 nid;     /*  0, node number */
-	__le16 nameoff; /*  8, start offset of file name */
-	__u8 file_type; /* 10, file type */
-	__u8 reserved;  /* 11, reserved */
+	__le64 nid;     /* node number */
+	__le16 nameoff; /* start offset of file name */
+	__u8 file_type; /* file type */
+	__u8 reserved;  /* reserved */
 } __packed;
 
 /*
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v2 02/25] erofs: on-disk format should have explicitly assigned numbers
  2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
  2019-09-04  2:08     ` [PATCH v2 01/25] erofs: remove all the byte offset comments Gao Xiang
@ 2019-09-04  2:08     ` Gao Xiang
  2019-09-04  2:08     ` [PATCH v2 03/25] erofs: some macros are much more readable as a function Gao Xiang
                       ` (24 subsequent siblings)
  26 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-04  2:08 UTC (permalink / raw)
  To: Chao Yu, Greg Kroah-Hartman, Christoph Hellwig, devel
  Cc: linux-fsdevel, linux-erofs, Chao Yu, Miao Xie, Gao Xiang

As Christoph suggested [1], on-disk format should have
explicitly assigned numbers.

[1] https://lore.kernel.org/r/20190829095954.GB20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/erofs_fs.h | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
index 49335fff9d65..d1f152a3670a 100644
--- a/fs/erofs/erofs_fs.h
+++ b/fs/erofs/erofs_fs.h
@@ -53,10 +53,10 @@ struct erofs_super_block {
  * 4~7 - reserved
  */
 enum {
-	EROFS_INODE_FLAT_PLAIN,
-	EROFS_INODE_FLAT_COMPRESSION_LEGACY,
-	EROFS_INODE_FLAT_INLINE,
-	EROFS_INODE_FLAT_COMPRESSION,
+	EROFS_INODE_FLAT_PLAIN			= 0,
+	EROFS_INODE_FLAT_COMPRESSION_LEGACY	= 1,
+	EROFS_INODE_FLAT_INLINE			= 2,
+	EROFS_INODE_FLAT_COMPRESSION		= 3,
 	EROFS_INODE_LAYOUT_MAX
 };
 
@@ -184,7 +184,7 @@ struct erofs_xattr_entry {
 
 /* available compression algorithm types */
 enum {
-	Z_EROFS_COMPRESSION_LZ4,
+	Z_EROFS_COMPRESSION_LZ4	= 0,
 	Z_EROFS_COMPRESSION_MAX
 };
 
@@ -242,10 +242,10 @@ struct z_erofs_map_header {
  *                (di_advise could be 0, 1 or 2)
  */
 enum {
-	Z_EROFS_VLE_CLUSTER_TYPE_PLAIN,
-	Z_EROFS_VLE_CLUSTER_TYPE_HEAD,
-	Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD,
-	Z_EROFS_VLE_CLUSTER_TYPE_RESERVED,
+	Z_EROFS_VLE_CLUSTER_TYPE_PLAIN		= 0,
+	Z_EROFS_VLE_CLUSTER_TYPE_HEAD		= 1,
+	Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD	= 2,
+	Z_EROFS_VLE_CLUSTER_TYPE_RESERVED	= 3,
 	Z_EROFS_VLE_CLUSTER_TYPE_MAX
 };
 
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v2 03/25] erofs: some macros are much more readable as a function
  2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
  2019-09-04  2:08     ` [PATCH v2 01/25] erofs: remove all the byte offset comments Gao Xiang
  2019-09-04  2:08     ` [PATCH v2 02/25] erofs: on-disk format should have explicitly assigned numbers Gao Xiang
@ 2019-09-04  2:08     ` Gao Xiang
  2019-09-04  2:08     ` [PATCH v2 04/25] erofs: kill __packed for on-disk structures Gao Xiang
                       ` (23 subsequent siblings)
  26 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-04  2:08 UTC (permalink / raw)
  To: Chao Yu, Greg Kroah-Hartman, Christoph Hellwig, devel
  Cc: linux-fsdevel, linux-erofs, Chao Yu, Miao Xie, Gao Xiang

As Christoph suggested [1], these macros are much
more readable as a function.

[1] https://lore.kernel.org/r/20190829095954.GB20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/erofs_fs.h | 22 ++++++++++++++--------
 fs/erofs/inode.c    |  4 ++--
 fs/erofs/xattr.c    |  2 +-
 3 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
index d1f152a3670a..c1220b0f26e0 100644
--- a/fs/erofs/erofs_fs.h
+++ b/fs/erofs/erofs_fs.h
@@ -171,16 +171,22 @@ struct erofs_xattr_entry {
 	char   e_name[0];       /* attribute name */
 } __packed;
 
-#define ondisk_xattr_ibody_size(count)	({\
-	u32 __count = le16_to_cpu(count); \
-	((__count) == 0) ? 0 : \
-	sizeof(struct erofs_xattr_ibody_header) + \
-		sizeof(__u32) * ((__count) - 1); })
+static inline unsigned int erofs_xattr_ibody_size(__le16 i_xattr_icount)
+{
+	if (!i_xattr_icount)
+		return 0;
+
+	return sizeof(struct erofs_xattr_ibody_header) +
+		sizeof(__u32) * (le16_to_cpu(i_xattr_icount) - 1);
+}
 
 #define EROFS_XATTR_ALIGN(size) round_up(size, sizeof(struct erofs_xattr_entry))
-#define EROFS_XATTR_ENTRY_SIZE(entry) EROFS_XATTR_ALIGN( \
-	sizeof(struct erofs_xattr_entry) + \
-	(entry)->e_name_len + le16_to_cpu((entry)->e_value_size))
+
+static inline unsigned int erofs_xattr_entry_size(struct erofs_xattr_entry *e)
+{
+	return EROFS_XATTR_ALIGN(sizeof(struct erofs_xattr_entry) +
+				 e->e_name_len + le16_to_cpu(e->e_value_size));
+}
 
 /* available compression algorithm types */
 enum {
diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index 8a0574530a0a..3fc4f764b387 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -29,7 +29,7 @@ static int read_inode(struct inode *inode, void *data)
 		struct erofs_inode_v2 *v2 = data;
 
 		vi->inode_isize = sizeof(struct erofs_inode_v2);
-		vi->xattr_isize = ondisk_xattr_ibody_size(v2->i_xattr_icount);
+		vi->xattr_isize = erofs_xattr_ibody_size(v2->i_xattr_icount);
 
 		inode->i_mode = le16_to_cpu(v2->i_mode);
 		if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
@@ -62,7 +62,7 @@ static int read_inode(struct inode *inode, void *data)
 		struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
 
 		vi->inode_isize = sizeof(struct erofs_inode_v1);
-		vi->xattr_isize = ondisk_xattr_ibody_size(v1->i_xattr_icount);
+		vi->xattr_isize = erofs_xattr_ibody_size(v1->i_xattr_icount);
 
 		inode->i_mode = le16_to_cpu(v1->i_mode);
 		if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c
index d80f61dde72f..620cbc15f4d0 100644
--- a/fs/erofs/xattr.c
+++ b/fs/erofs/xattr.c
@@ -231,7 +231,7 @@ static int xattr_foreach(struct xattr_iter *it,
 	 */
 	entry = *(struct erofs_xattr_entry *)(it->kaddr + it->ofs);
 	if (tlimit) {
-		unsigned int entry_sz = EROFS_XATTR_ENTRY_SIZE(&entry);
+		unsigned int entry_sz = erofs_xattr_entry_size(&entry);
 
 		/* xattr on-disk corruption: xattr entry beyond xattr_isize */
 		if (*tlimit < entry_sz) {
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v2 04/25] erofs: kill __packed for on-disk structures
  2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
                       ` (2 preceding siblings ...)
  2019-09-04  2:08     ` [PATCH v2 03/25] erofs: some macros are much more readable as a function Gao Xiang
@ 2019-09-04  2:08     ` Gao Xiang
  2019-09-04  2:08     ` [PATCH v2 05/25] erofs: update erofs_inode_is_data_compressed helper Gao Xiang
                       ` (22 subsequent siblings)
  26 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-04  2:08 UTC (permalink / raw)
  To: Chao Yu, Greg Kroah-Hartman, Christoph Hellwig, devel
  Cc: linux-fsdevel, linux-erofs, Chao Yu, Miao Xie, Gao Xiang

As Christoph suggested "Please don't add __packed" [1],
remove all __packed except struct erofs_dirent here.

Note that all on-disk fields except struct erofs_dirent
(12 bytes with a 8-byte nid) in EROFS are naturally aligned.

[1] https://lore.kernel.org/r/20190829095954.GB20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/erofs_fs.h | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
index c1220b0f26e0..59dcc2e8cb02 100644
--- a/fs/erofs/erofs_fs.h
+++ b/fs/erofs/erofs_fs.h
@@ -38,7 +38,7 @@ struct erofs_super_block {
 	__le32 requirements;    /* (aka. feature_incompat) */
 
 	__u8 reserved2[44];
-} __packed;
+};
 
 /*
  * erofs inode data mapping:
@@ -91,12 +91,12 @@ struct erofs_inode_v1 {
 
 		/* for device files, used to indicate old/new device # */
 		__le32 rdev;
-	} i_u __packed;
+	} i_u;
 	__le32 i_ino;           /* only used for 32-bit stat compatibility */
 	__le16 i_uid;
 	__le16 i_gid;
 	__le32 i_reserved2;
-} __packed;
+};
 
 /* 32 bytes on-disk inode */
 #define EROFS_INODE_LAYOUT_V1   0
@@ -119,7 +119,7 @@ struct erofs_inode_v2 {
 
 		/* for device files, used to indicate old/new device # */
 		__le32 rdev;
-	} i_u __packed;
+	} i_u;
 
 	/* only used for 32-bit stat compatibility */
 	__le32 i_ino;
@@ -130,7 +130,7 @@ struct erofs_inode_v2 {
 	__le32 i_ctime_nsec;
 	__le32 i_nlink;
 	__u8   i_reserved2[16];
-} __packed;
+};
 
 #define EROFS_MAX_SHARED_XATTRS         (128)
 /* h_shared_count between 129 ... 255 are special # */
@@ -152,7 +152,7 @@ struct erofs_xattr_ibody_header {
 	__u8   h_shared_count;
 	__u8   h_reserved2[7];
 	__le32 h_shared_xattrs[0];      /* shared xattr id array */
-} __packed;
+};
 
 /* Name indexes */
 #define EROFS_XATTR_INDEX_USER              1
@@ -169,7 +169,7 @@ struct erofs_xattr_entry {
 	__le16 e_value_size;    /* size of attribute value */
 	/* followed by e_name and e_value */
 	char   e_name[0];       /* attribute name */
-} __packed;
+};
 
 static inline unsigned int erofs_xattr_ibody_size(__le16 i_xattr_icount)
 {
@@ -273,8 +273,8 @@ struct z_erofs_vle_decompressed_index {
 		 * [1] - pointing to the tail cluster
 		 */
 		__le16 delta[2];
-	} di_u __packed;
-} __packed;
+	} di_u;
+};
 
 #define Z_EROFS_VLE_LEGACY_INDEX_ALIGN(size) \
 	(round_up(size, sizeof(struct z_erofs_vle_decompressed_index)) + \
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v2 05/25] erofs: update erofs_inode_is_data_compressed helper
  2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
                       ` (3 preceding siblings ...)
  2019-09-04  2:08     ` [PATCH v2 04/25] erofs: kill __packed for on-disk structures Gao Xiang
@ 2019-09-04  2:08     ` Gao Xiang
  2019-09-04  2:08     ` [PATCH v2 06/25] erofs: use feature_incompat rather than requirements Gao Xiang
                       ` (21 subsequent siblings)
  26 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-04  2:08 UTC (permalink / raw)
  To: Chao Yu, Greg Kroah-Hartman, Christoph Hellwig, devel
  Cc: linux-fsdevel, linux-erofs, Chao Yu, Miao Xie, Gao Xiang

As Christoph said, "This looks like a really obsfucated
way to write:
	return datamode == EROFS_INODE_FLAT_COMPRESSION ||
		datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY; "

Although I had my own consideration, it's the right way for now.

[1] https://lore.kernel.org/r/20190829095954.GB20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/erofs_fs.h | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
index 59dcc2e8cb02..87d7ae82339a 100644
--- a/fs/erofs/erofs_fs.h
+++ b/fs/erofs/erofs_fs.h
@@ -62,9 +62,8 @@ enum {
 
 static inline bool erofs_inode_is_data_compressed(unsigned int datamode)
 {
-	if (datamode == EROFS_INODE_FLAT_COMPRESSION)
-		return true;
-	return datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY;
+	return datamode == EROFS_INODE_FLAT_COMPRESSION ||
+		datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY;
 }
 
 /* bit definitions of inode i_advise */
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v2 06/25] erofs: use feature_incompat rather than requirements
  2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
                       ` (4 preceding siblings ...)
  2019-09-04  2:08     ` [PATCH v2 05/25] erofs: update erofs_inode_is_data_compressed helper Gao Xiang
@ 2019-09-04  2:08     ` Gao Xiang
  2019-09-04  2:08     ` [PATCH v2 07/25] erofs: better naming for erofs inode related stuffs Gao Xiang
                       ` (20 subsequent siblings)
  26 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-04  2:08 UTC (permalink / raw)
  To: Chao Yu, Greg Kroah-Hartman, Christoph Hellwig, devel
  Cc: linux-fsdevel, linux-erofs, Chao Yu, Miao Xie, Gao Xiang

As Christoph said [1], "This is only cosmetic, why
not stick to feature_compat and feature_incompat?"

In my thought, requirements means "incompatible"
instead of "feature" though.

[1] https://lore.kernel.org/r/20190902125109.GA9826@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/decompressor.c |  3 ++-
 fs/erofs/erofs_fs.h     | 12 ++++++------
 fs/erofs/internal.h     |  2 +-
 fs/erofs/super.c        | 10 +++++-----
 4 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index df349888f911..555c04730f87 100644
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -129,7 +129,8 @@ static int lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out)
 	support_0padding = false;
 
 	/* decompression inplace is only safe when 0padding is enabled */
-	if (EROFS_SB(rq->sb)->requirements & EROFS_REQUIREMENT_LZ4_0PADDING) {
+	if (EROFS_SB(rq->sb)->feature_incompat &
+	    EROFS_FEATURE_INCOMPAT_LZ4_0PADDING) {
 		support_0padding = true;
 
 		while (!src[inputmargin & ~PAGE_MASK])
diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
index 87d7ae82339a..b2aef3bc377d 100644
--- a/fs/erofs/erofs_fs.h
+++ b/fs/erofs/erofs_fs.h
@@ -11,17 +11,17 @@
 #define EROFS_SUPER_OFFSET      1024
 
 /*
- * Any bits that aren't in EROFS_ALL_REQUIREMENTS should be
- * incompatible with this kernel version.
+ * Any bits that aren't in EROFS_ALL_FEATURE_INCOMPAT should
+ * be incompatible with this kernel version.
  */
-#define EROFS_REQUIREMENT_LZ4_0PADDING	0x00000001
-#define EROFS_ALL_REQUIREMENTS		EROFS_REQUIREMENT_LZ4_0PADDING
+#define EROFS_FEATURE_INCOMPAT_LZ4_0PADDING	0x00000001
+#define EROFS_ALL_FEATURE_INCOMPAT		EROFS_FEATURE_INCOMPAT_LZ4_0PADDING
 
 /* 128-byte erofs on-disk super block */
 struct erofs_super_block {
 	__le32 magic;           /* file system magic number */
 	__le32 checksum;        /* crc32c(super_block) */
-	__le32 features;        /* (aka. feature_compat) */
+	__le32 feature_compat;
 	__u8 blkszbits;         /* support block_size == PAGE_SIZE only */
 	__u8 reserved;
 
@@ -35,7 +35,7 @@ struct erofs_super_block {
 	__le32 xattr_blkaddr;	/* start block address of shared xattr area */
 	__u8 uuid[16];          /* 128-bit uuid for volume */
 	__u8 volume_name[16];   /* volume name */
-	__le32 requirements;    /* (aka. feature_incompat) */
+	__le32 feature_incompat;
 
 	__u8 reserved2[44];
 };
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 141ea424587d..7ff36f404ec3 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -96,7 +96,7 @@ struct erofs_sb_info {
 
 	u8 uuid[16];                    /* 128-bit uuid for volume */
 	u8 volume_name[16];             /* volume name */
-	u32 requirements;
+	u32 feature_incompat;
 
 	unsigned int mount_opt;
 
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 6603f0ba8905..6a7ab194783c 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -67,14 +67,14 @@ static void free_inode(struct inode *inode)
 static bool check_layout_compatibility(struct super_block *sb,
 				       struct erofs_super_block *layout)
 {
-	const unsigned int requirements = le32_to_cpu(layout->requirements);
+	const unsigned int feature = le32_to_cpu(layout->feature_incompat);
 
-	EROFS_SB(sb)->requirements = requirements;
+	EROFS_SB(sb)->feature_incompat = feature;
 
 	/* check if current kernel meets all mandatory requirements */
-	if (requirements & (~EROFS_ALL_REQUIREMENTS)) {
-		errln("unidentified requirements %x, please upgrade kernel version",
-		      requirements & ~EROFS_ALL_REQUIREMENTS);
+	if (feature & (~EROFS_ALL_FEATURE_INCOMPAT)) {
+		errln("unidentified incompatible feature %x, please upgrade kernel version",
+		      feature & ~EROFS_ALL_FEATURE_INCOMPAT);
 		return false;
 	}
 	return true;
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v2 07/25] erofs: better naming for erofs inode related stuffs
  2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
                       ` (5 preceding siblings ...)
  2019-09-04  2:08     ` [PATCH v2 06/25] erofs: use feature_incompat rather than requirements Gao Xiang
@ 2019-09-04  2:08     ` Gao Xiang
  2019-09-04  2:08     ` [PATCH v2 08/25] erofs: kill erofs_{init,exit}_inode_cache Gao Xiang
                       ` (19 subsequent siblings)
  26 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-04  2:08 UTC (permalink / raw)
  To: Chao Yu, Greg Kroah-Hartman, Christoph Hellwig, devel
  Cc: linux-fsdevel, linux-erofs, Chao Yu, Miao Xie, Gao Xiang

updates inode naming
 - kill is_inode_layout_compression [1]
 - kill magic underscores [2] [3]
 - better naming for datamode & data_mapping_mode [3]
 - better naming erofs_inode_{compact, extended} [4]

[1] https://lore.kernel.org/r/20190829102426.GE20598@infradead.org/
[2] https://lore.kernel.org/r/20190829102426.GE20598@infradead.org/
[3] https://lore.kernel.org/r/20190902122627.GN15931@infradead.org/
[4] https://lore.kernel.org/r/20190902125438.GA17750@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/data.c     |   9 ++--
 fs/erofs/erofs_fs.h |  24 ++++-----
 fs/erofs/inode.c    | 126 +++++++++++++++++++++++++-------------------
 fs/erofs/internal.h |  31 ++++++-----
 fs/erofs/super.c    |   2 +-
 fs/erofs/zmap.c     |   6 +--
 6 files changed, 108 insertions(+), 90 deletions(-)

diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index 0983807737fd..4d9b07991d07 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -113,11 +113,12 @@ static int erofs_map_blocks_flatmode(struct inode *inode,
 	erofs_blk_t nblocks, lastblk;
 	u64 offset = map->m_la;
 	struct erofs_vnode *vi = EROFS_V(inode);
+	bool tailendpacking = (vi->datalayout == EROFS_INODE_FLAT_INLINE);
 
 	trace_erofs_map_blocks_flatmode_enter(inode, map, flags);
 
 	nblocks = DIV_ROUND_UP(inode->i_size, PAGE_SIZE);
-	lastblk = nblocks - is_inode_flat_inline(inode);
+	lastblk = nblocks - tailendpacking;
 
 	if (offset >= inode->i_size) {
 		/* leave out-of-bound access unmapped */
@@ -132,7 +133,7 @@ static int erofs_map_blocks_flatmode(struct inode *inode,
 	if (offset < blknr_to_addr(lastblk)) {
 		map->m_pa = blknr_to_addr(vi->raw_blkaddr) + map->m_la;
 		map->m_plen = blknr_to_addr(lastblk) - offset;
-	} else if (is_inode_flat_inline(inode)) {
+	} else if (tailendpacking) {
 		/* 2 - inode inline B: inode, [xattrs], inline last blk... */
 		struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
 
@@ -169,7 +170,7 @@ static int erofs_map_blocks_flatmode(struct inode *inode,
 int erofs_map_blocks(struct inode *inode,
 		     struct erofs_map_blocks *map, int flags)
 {
-	if (is_inode_layout_compression(inode)) {
+	if (erofs_inode_is_data_compressed(EROFS_V(inode)->datalayout)) {
 		int err = z_erofs_map_blocks_iter(inode, map, flags);
 
 		if (map->mpage) {
@@ -403,7 +404,7 @@ static sector_t erofs_bmap(struct address_space *mapping, sector_t block)
 {
 	struct inode *inode = mapping->host;
 
-	if (is_inode_flat_inline(inode)) {
+	if (EROFS_V(inode)->datalayout == EROFS_INODE_FLAT_INLINE) {
 		erofs_blk_t blks = i_size_read(inode) >> LOG_BLOCK_SIZE;
 
 		if (block >> LOG_SECTORS_PER_BLOCK >= blks)
diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
index b2aef3bc377d..18689e916e94 100644
--- a/fs/erofs/erofs_fs.h
+++ b/fs/erofs/erofs_fs.h
@@ -41,7 +41,7 @@ struct erofs_super_block {
 };
 
 /*
- * erofs inode data mapping:
+ * erofs inode datalayout:
  * 0 - inode plain without inline data A:
  * inode, [xattrs], ... | ... | no-holed data
  * 1 - inode VLE compression B (legacy):
@@ -57,7 +57,7 @@ enum {
 	EROFS_INODE_FLAT_COMPRESSION_LEGACY	= 1,
 	EROFS_INODE_FLAT_INLINE			= 2,
 	EROFS_INODE_FLAT_COMPRESSION		= 3,
-	EROFS_INODE_LAYOUT_MAX
+	EROFS_INODE_DATALAYOUT_MAX
 };
 
 static inline bool erofs_inode_is_data_compressed(unsigned int datamode)
@@ -68,14 +68,14 @@ static inline bool erofs_inode_is_data_compressed(unsigned int datamode)
 
 /* bit definitions of inode i_advise */
 #define EROFS_I_VERSION_BITS            1
-#define EROFS_I_DATA_MAPPING_BITS       3
+#define EROFS_I_DATALAYOUT_BITS         3
 
 #define EROFS_I_VERSION_BIT             0
-#define EROFS_I_DATA_MAPPING_BIT        1
+#define EROFS_I_DATALAYOUT_BIT          1
 
 /* 32-byte reduced form of an ondisk inode */
-struct erofs_inode_v1 {
-	__le16 i_advise;	/* inode hints */
+struct erofs_inode_compact {
+	__le16 i_format;	/* inode format hints */
 
 /* 1 header + n-1 * 4 bytes inline xattr to keep continuity */
 	__le16 i_xattr_icount;
@@ -98,13 +98,13 @@ struct erofs_inode_v1 {
 };
 
 /* 32 bytes on-disk inode */
-#define EROFS_INODE_LAYOUT_V1   0
+#define EROFS_INODE_LAYOUT_COMPACT	0
 /* 64 bytes on-disk inode */
-#define EROFS_INODE_LAYOUT_V2   1
+#define EROFS_INODE_LAYOUT_EXTENDED	1
 
 /* 64-byte complete form of an ondisk inode */
-struct erofs_inode_v2 {
-	__le16 i_advise;	/* inode hints */
+struct erofs_inode_extended {
+	__le16 i_format;	/* inode format hints */
 
 /* 1 header + n-1 * 4 bytes inline xattr to keep continuity */
 	__le16 i_xattr_icount;
@@ -299,8 +299,8 @@ struct erofs_dirent {
 static inline void erofs_check_ondisk_layout_definitions(void)
 {
 	BUILD_BUG_ON(sizeof(struct erofs_super_block) != 128);
-	BUILD_BUG_ON(sizeof(struct erofs_inode_v1) != 32);
-	BUILD_BUG_ON(sizeof(struct erofs_inode_v2) != 64);
+	BUILD_BUG_ON(sizeof(struct erofs_inode_compact) != 32);
+	BUILD_BUG_ON(sizeof(struct erofs_inode_extended) != 64);
 	BUILD_BUG_ON(sizeof(struct erofs_xattr_ibody_header) != 12);
 	BUILD_BUG_ON(sizeof(struct erofs_xattr_entry) != 4);
 	BUILD_BUG_ON(sizeof(struct z_erofs_map_header) != 8);
diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index 3fc4f764b387..494b35e5830a 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -12,73 +12,90 @@
 static int read_inode(struct inode *inode, void *data)
 {
 	struct erofs_vnode *vi = EROFS_V(inode);
-	struct erofs_inode_v1 *v1 = data;
-	const unsigned int advise = le16_to_cpu(v1->i_advise);
+	struct erofs_inode_compact *dic = data;
+	struct erofs_inode_extended *die;
+
+	const unsigned int ifmt = le16_to_cpu(dic->i_format);
+	struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
 	erofs_blk_t nblks = 0;
 
-	vi->datamode = __inode_data_mapping(advise);
+	vi->datalayout = erofs_inode_datalayout(ifmt);
 
-	if (vi->datamode >= EROFS_INODE_LAYOUT_MAX) {
-		errln("unsupported data mapping %u of nid %llu",
-		      vi->datamode, vi->nid);
+	if (vi->datalayout >= EROFS_INODE_DATALAYOUT_MAX) {
+		errln("unsupported datalayout %u of nid %llu",
+		      vi->datalayout, vi->nid);
 		DBG_BUGON(1);
 		return -EOPNOTSUPP;
 	}
 
-	if (__inode_version(advise) == EROFS_INODE_LAYOUT_V2) {
-		struct erofs_inode_v2 *v2 = data;
+	switch (erofs_inode_version(ifmt)) {
+	case EROFS_INODE_LAYOUT_EXTENDED:
+		die = data;
 
-		vi->inode_isize = sizeof(struct erofs_inode_v2);
-		vi->xattr_isize = erofs_xattr_ibody_size(v2->i_xattr_icount);
+		vi->inode_isize = sizeof(struct erofs_inode_extended);
+		vi->xattr_isize = erofs_xattr_ibody_size(die->i_xattr_icount);
 
-		inode->i_mode = le16_to_cpu(v2->i_mode);
-		if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
-		    S_ISLNK(inode->i_mode))
-			vi->raw_blkaddr = le32_to_cpu(v2->i_u.raw_blkaddr);
-		else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
+		inode->i_mode = le16_to_cpu(die->i_mode);
+		switch (inode->i_mode & S_IFMT) {
+		case S_IFREG:
+		case S_IFDIR:
+		case S_IFLNK:
+			vi->raw_blkaddr = le32_to_cpu(die->i_u.raw_blkaddr);
+			break;
+		case S_IFCHR:
+		case S_IFBLK:
 			inode->i_rdev =
-				new_decode_dev(le32_to_cpu(v2->i_u.rdev));
-		else if (S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode))
+				new_decode_dev(le32_to_cpu(die->i_u.rdev));
+			break;
+		case S_IFIFO:
+		case S_IFSOCK:
 			inode->i_rdev = 0;
-		else
+			break;
+		default:
 			goto bogusimode;
-
-		i_uid_write(inode, le32_to_cpu(v2->i_uid));
-		i_gid_write(inode, le32_to_cpu(v2->i_gid));
-		set_nlink(inode, le32_to_cpu(v2->i_nlink));
+		}
+		i_uid_write(inode, le32_to_cpu(die->i_uid));
+		i_gid_write(inode, le32_to_cpu(die->i_gid));
+		set_nlink(inode, le32_to_cpu(die->i_nlink));
 
 		/* ns timestamp */
 		inode->i_mtime.tv_sec = inode->i_ctime.tv_sec =
-			le64_to_cpu(v2->i_ctime);
+			le64_to_cpu(die->i_ctime);
 		inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec =
-			le32_to_cpu(v2->i_ctime_nsec);
+			le32_to_cpu(die->i_ctime_nsec);
 
-		inode->i_size = le64_to_cpu(v2->i_size);
+		inode->i_size = le64_to_cpu(die->i_size);
 
 		/* total blocks for compressed files */
-		if (is_inode_layout_compression(inode))
-			nblks = le32_to_cpu(v2->i_u.compressed_blocks);
-	} else if (__inode_version(advise) == EROFS_INODE_LAYOUT_V1) {
-		struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
-
-		vi->inode_isize = sizeof(struct erofs_inode_v1);
-		vi->xattr_isize = erofs_xattr_ibody_size(v1->i_xattr_icount);
-
-		inode->i_mode = le16_to_cpu(v1->i_mode);
-		if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
-		    S_ISLNK(inode->i_mode))
-			vi->raw_blkaddr = le32_to_cpu(v1->i_u.raw_blkaddr);
-		else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
+		if (erofs_inode_is_data_compressed(vi->datalayout))
+			nblks = le32_to_cpu(die->i_u.compressed_blocks);
+		break;
+	case EROFS_INODE_LAYOUT_COMPACT:
+		vi->inode_isize = sizeof(struct erofs_inode_compact);
+		vi->xattr_isize = erofs_xattr_ibody_size(dic->i_xattr_icount);
+
+		inode->i_mode = le16_to_cpu(dic->i_mode);
+		switch (inode->i_mode & S_IFMT) {
+		case S_IFREG:
+		case S_IFDIR:
+		case S_IFLNK:
+			vi->raw_blkaddr = le32_to_cpu(dic->i_u.raw_blkaddr);
+			break;
+		case S_IFCHR:
+		case S_IFBLK:
 			inode->i_rdev =
-				new_decode_dev(le32_to_cpu(v1->i_u.rdev));
-		else if (S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode))
+				new_decode_dev(le32_to_cpu(dic->i_u.rdev));
+			break;
+		case S_IFIFO:
+		case S_IFSOCK:
 			inode->i_rdev = 0;
-		else
+			break;
+		default:
 			goto bogusimode;
-
-		i_uid_write(inode, le16_to_cpu(v1->i_uid));
-		i_gid_write(inode, le16_to_cpu(v1->i_gid));
-		set_nlink(inode, le16_to_cpu(v1->i_nlink));
+		}
+		i_uid_write(inode, le16_to_cpu(dic->i_uid));
+		i_gid_write(inode, le16_to_cpu(dic->i_gid));
+		set_nlink(inode, le16_to_cpu(dic->i_nlink));
 
 		/* use build time to derive all file time */
 		inode->i_mtime.tv_sec = inode->i_ctime.tv_sec =
@@ -86,12 +103,13 @@ static int read_inode(struct inode *inode, void *data)
 		inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec =
 			sbi->build_time_nsec;
 
-		inode->i_size = le32_to_cpu(v1->i_size);
-		if (is_inode_layout_compression(inode))
-			nblks = le32_to_cpu(v1->i_u.compressed_blocks);
-	} else {
+		inode->i_size = le32_to_cpu(dic->i_size);
+		if (erofs_inode_is_data_compressed(vi->datalayout))
+			nblks = le32_to_cpu(dic->i_u.compressed_blocks);
+		break;
+	default:
 		errln("unsupported on-disk inode version %u of nid %llu",
-		      __inode_version(advise), vi->nid);
+		      erofs_inode_version(ifmt), vi->nid);
 		DBG_BUGON(1);
 		return -EOPNOTSUPP;
 	}
@@ -125,8 +143,8 @@ static int fill_inline_data(struct inode *inode, void *data,
 	struct erofs_vnode *vi = EROFS_V(inode);
 	struct erofs_sb_info *sbi = EROFS_I_SB(inode);
 
-	/* should be inode inline C */
-	if (!is_inode_flat_inline(inode))
+	/* should be tail-packing data inline */
+	if (vi->datalayout != EROFS_INODE_FLAT_INLINE)
 		return 0;
 
 	/* fast symlink (following ext4) */
@@ -216,7 +234,7 @@ static int fill_inode(struct inode *inode, int isdir)
 			goto out_unlock;
 		}
 
-		if (is_inode_layout_compression(inode)) {
+		if (erofs_inode_is_data_compressed(vi->datalayout)) {
 			err = z_erofs_fill_inode(inode);
 			goto out_unlock;
 		}
@@ -299,7 +317,7 @@ int erofs_getattr(const struct path *path, struct kstat *stat,
 {
 	struct inode *const inode = d_inode(path->dentry);
 
-	if (is_inode_layout_compression(inode))
+	if (erofs_inode_is_data_compressed(EROFS_V(inode)->datalayout))
 		stat->attributes |= STATX_ATTR_COMPRESSED;
 
 	stat->attributes |= STATX_ATTR_IMMUTABLE;
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 7ff36f404ec3..0f5cbf0a7570 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -285,7 +285,7 @@ struct erofs_vnode {
 	/* atomic flags (including bitlocks) */
 	unsigned long flags;
 
-	unsigned char datamode;
+	unsigned char datalayout;
 	unsigned char inode_isize;
 	unsigned short xattr_isize;
 
@@ -310,31 +310,30 @@ struct erofs_vnode {
 #define EROFS_V(ptr)	\
 	container_of(ptr, struct erofs_vnode, vfs_inode)
 
-#define __inode_advise(x, bit, bits) \
-	(((x) >> (bit)) & ((1 << (bits)) - 1))
-
-#define __inode_version(advise)	\
-	__inode_advise(advise, EROFS_I_VERSION_BIT,	\
-		EROFS_I_VERSION_BITS)
-
-#define __inode_data_mapping(advise)	\
-	__inode_advise(advise, EROFS_I_DATA_MAPPING_BIT,\
-		EROFS_I_DATA_MAPPING_BITS)
-
 static inline unsigned long inode_datablocks(struct inode *inode)
 {
 	/* since i_size cannot be changed */
 	return DIV_ROUND_UP(inode->i_size, EROFS_BLKSIZ);
 }
 
-static inline bool is_inode_layout_compression(struct inode *inode)
+static inline unsigned int erofs_bitrange(unsigned int value, unsigned int bit,
+					  unsigned int bits)
+{
+
+	return (value >> bit) & ((1 << bits) - 1);
+}
+
+
+static inline unsigned int erofs_inode_version(unsigned int value)
 {
-	return erofs_inode_is_data_compressed(EROFS_V(inode)->datamode);
+	return erofs_bitrange(value, EROFS_I_VERSION_BIT,
+			      EROFS_I_VERSION_BITS);
 }
 
-static inline bool is_inode_flat_inline(struct inode *inode)
+static inline unsigned int erofs_inode_datalayout(unsigned int value)
 {
-	return EROFS_V(inode)->datamode == EROFS_INODE_FLAT_INLINE;
+	return erofs_bitrange(value, EROFS_I_DATALAYOUT_BIT,
+			      EROFS_I_DATALAYOUT_BITS);
 }
 
 extern const struct super_operations erofs_sops;
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 6a7ab194783c..8d9f38d56b3b 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -121,7 +121,7 @@ static int superblock_read(struct super_block *sb)
 #ifdef CONFIG_EROFS_FS_XATTR
 	sbi->xattr_blkaddr = le32_to_cpu(layout->xattr_blkaddr);
 #endif
-	sbi->islotbits = ffs(sizeof(struct erofs_inode_v1)) - 1;
+	sbi->islotbits = ilog2(sizeof(struct erofs_inode_compact));
 	sbi->root_nid = le16_to_cpu(layout->root_nid);
 	sbi->inos = le64_to_cpu(layout->inos);
 
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index 850e0e3d57a8..6a06fb80ef3f 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -12,7 +12,7 @@ int z_erofs_fill_inode(struct inode *inode)
 {
 	struct erofs_vnode *const vi = EROFS_V(inode);
 
-	if (vi->datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY) {
+	if (vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY) {
 		vi->z_advise = 0;
 		vi->z_algorithmtype[0] = 0;
 		vi->z_algorithmtype[1] = 0;
@@ -46,7 +46,7 @@ static int fill_inode_lazy(struct inode *inode)
 	if (test_bit(EROFS_V_Z_INITED_BIT, &vi->flags))
 		goto out_unlock;
 
-	DBG_BUGON(vi->datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY);
+	DBG_BUGON(vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY);
 
 	pos = ALIGN(iloc(EROFS_SB(sb), vi->nid) + vi->inode_isize +
 		    vi->xattr_isize, 8);
@@ -314,7 +314,7 @@ static int compacted_load_cluster_from_disk(struct z_erofs_maprecorder *m,
 static int vle_load_cluster_from_disk(struct z_erofs_maprecorder *m,
 				      unsigned int lcn)
 {
-	const unsigned int datamode = EROFS_V(m->inode)->datamode;
+	const unsigned int datamode = EROFS_V(m->inode)->datalayout;
 
 	if (datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY)
 		return vle_legacy_load_cluster_from_disk(m, lcn);
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v2 08/25] erofs: kill erofs_{init,exit}_inode_cache
  2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
                       ` (6 preceding siblings ...)
  2019-09-04  2:08     ` [PATCH v2 07/25] erofs: better naming for erofs inode related stuffs Gao Xiang
@ 2019-09-04  2:08     ` Gao Xiang
  2019-09-04  2:08     ` [PATCH v2 09/25] erofs: use erofs_inode naming Gao Xiang
                       ` (18 subsequent siblings)
  26 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-04  2:08 UTC (permalink / raw)
  To: Chao Yu, Greg Kroah-Hartman, Christoph Hellwig, devel
  Cc: linux-fsdevel, linux-erofs, Chao Yu, Miao Xie, Gao Xiang

As Christoph said [1] "having this function seems
entirely pointless", let's kill those.

filesystem                              function name
ext2,f2fs,ext4,isofs,squashfs,cifs,...  init_inodecache

In addition, add a necessary "rcu_barrier()" on exit_fs();

[1] https://lore.kernel.org/r/20190829101545.GC20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/super.c | 31 ++++++++++++-------------------
 1 file changed, 12 insertions(+), 19 deletions(-)

diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 8d9f38d56b3b..499dc7f5d0e6 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -23,21 +23,6 @@ static void init_once(void *ptr)
 	inode_init_once(&vi->vfs_inode);
 }
 
-static int __init erofs_init_inode_cache(void)
-{
-	erofs_inode_cachep = kmem_cache_create("erofs_inode",
-					       sizeof(struct erofs_vnode), 0,
-					       SLAB_RECLAIM_ACCOUNT,
-					       init_once);
-
-	return erofs_inode_cachep ? 0 : -ENOMEM;
-}
-
-static void erofs_exit_inode_cache(void)
-{
-	kmem_cache_destroy(erofs_inode_cachep);
-}
-
 static struct inode *alloc_inode(struct super_block *sb)
 {
 	struct erofs_vnode *vi =
@@ -531,9 +516,14 @@ static int __init erofs_module_init(void)
 	erofs_check_ondisk_layout_definitions();
 	infoln("initializing erofs " EROFS_VERSION);
 
-	err = erofs_init_inode_cache();
-	if (err)
+	erofs_inode_cachep = kmem_cache_create("erofs_inode",
+					       sizeof(struct erofs_vnode), 0,
+					       SLAB_RECLAIM_ACCOUNT,
+					       init_once);
+	if (!erofs_inode_cachep) {
+		err = -ENOMEM;
 		goto icache_err;
+	}
 
 	err = erofs_init_shrinker();
 	if (err)
@@ -555,7 +545,7 @@ static int __init erofs_module_init(void)
 zip_err:
 	erofs_exit_shrinker();
 shrinker_err:
-	erofs_exit_inode_cache();
+	kmem_cache_destroy(erofs_inode_cachep);
 icache_err:
 	return err;
 }
@@ -565,7 +555,10 @@ static void __exit erofs_module_exit(void)
 	unregister_filesystem(&erofs_fs_type);
 	z_erofs_exit_zip_subsystem();
 	erofs_exit_shrinker();
-	erofs_exit_inode_cache();
+
+	/* Ensure all RCU free inodes are safe before cache is destroyed. */
+	rcu_barrier();
+	kmem_cache_destroy(erofs_inode_cachep);
 	infoln("successfully finalize erofs");
 }
 
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v2 09/25] erofs: use erofs_inode naming
  2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
                       ` (7 preceding siblings ...)
  2019-09-04  2:08     ` [PATCH v2 08/25] erofs: kill erofs_{init,exit}_inode_cache Gao Xiang
@ 2019-09-04  2:08     ` Gao Xiang
  2019-09-04  2:08     ` [PATCH v2 10/25] erofs: update erofs_fs.h comments Gao Xiang
                       ` (17 subsequent siblings)
  26 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-04  2:08 UTC (permalink / raw)
  To: Chao Yu, Greg Kroah-Hartman, Christoph Hellwig, devel
  Cc: linux-fsdevel, linux-erofs, Chao Yu, Miao Xie, Gao Xiang

As Christoph suggested [1], "Why is this called vnode instead
of inode?  That seems like a rather odd naming for a Linux
file system."

[1] https://lore.kernel.org/r/20190829101545.GC20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/data.c              |  8 ++++----
 fs/erofs/dir.c               |  6 +++---
 fs/erofs/inode.c             | 12 ++++++------
 fs/erofs/internal.h          | 14 +++++++-------
 fs/erofs/namei.c             |  2 +-
 fs/erofs/super.c             | 10 +++++-----
 fs/erofs/xattr.c             | 18 +++++++++---------
 fs/erofs/xattr.h             |  4 ++--
 fs/erofs/zdata.c             |  9 +++------
 fs/erofs/zmap.c              | 28 ++++++++++++++--------------
 include/trace/events/erofs.h | 14 +++++++-------
 11 files changed, 61 insertions(+), 64 deletions(-)

diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index 4d9b07991d07..be11b5ea9d2e 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -112,7 +112,7 @@ static int erofs_map_blocks_flatmode(struct inode *inode,
 	int err = 0;
 	erofs_blk_t nblocks, lastblk;
 	u64 offset = map->m_la;
-	struct erofs_vnode *vi = EROFS_V(inode);
+	struct erofs_inode *vi = EROFS_I(inode);
 	bool tailendpacking = (vi->datalayout == EROFS_INODE_FLAT_INLINE);
 
 	trace_erofs_map_blocks_flatmode_enter(inode, map, flags);
@@ -170,7 +170,7 @@ static int erofs_map_blocks_flatmode(struct inode *inode,
 int erofs_map_blocks(struct inode *inode,
 		     struct erofs_map_blocks *map, int flags)
 {
-	if (erofs_inode_is_data_compressed(EROFS_V(inode)->datalayout)) {
+	if (erofs_inode_is_data_compressed(EROFS_I(inode)->datalayout)) {
 		int err = z_erofs_map_blocks_iter(inode, map, flags);
 
 		if (map->mpage) {
@@ -365,7 +365,7 @@ static int erofs_raw_access_readpages(struct file *filp,
 			if (IS_ERR(bio)) {
 				pr_err("%s, readahead error at page %lu of nid %llu\n",
 				       __func__, page->index,
-				       EROFS_V(mapping->host)->nid);
+				       EROFS_I(mapping->host)->nid);
 
 				bio = NULL;
 			}
@@ -404,7 +404,7 @@ static sector_t erofs_bmap(struct address_space *mapping, sector_t block)
 {
 	struct inode *inode = mapping->host;
 
-	if (EROFS_V(inode)->datalayout == EROFS_INODE_FLAT_INLINE) {
+	if (EROFS_I(inode)->datalayout == EROFS_INODE_FLAT_INLINE) {
 		erofs_blk_t blks = i_size_read(inode) >> LOG_BLOCK_SIZE;
 
 		if (block >> LOG_SECTORS_PER_BLOCK >= blks)
diff --git a/fs/erofs/dir.c b/fs/erofs/dir.c
index 6a5b43f7fb29..a032c8217071 100644
--- a/fs/erofs/dir.c
+++ b/fs/erofs/dir.c
@@ -47,7 +47,7 @@ static int erofs_fill_dentries(struct inode *dir, struct dir_context *ctx,
 		/* a corrupted entry is found */
 		if (nameoff + de_namelen > maxsize ||
 		    de_namelen > EROFS_NAME_LEN) {
-			errln("bogus dirent @ nid %llu", EROFS_V(dir)->nid);
+			errln("bogus dirent @ nid %llu", EROFS_I(dir)->nid);
 			DBG_BUGON(1);
 			return -EFSCORRUPTED;
 		}
@@ -85,7 +85,7 @@ static int erofs_readdir(struct file *f, struct dir_context *ctx)
 			break;
 		} else if (IS_ERR(dentry_page)) {
 			errln("fail to readdir of logical block %u of nid %llu",
-			      i, EROFS_V(dir)->nid);
+			      i, EROFS_I(dir)->nid);
 			err = -EFSCORRUPTED;
 			break;
 		}
@@ -97,7 +97,7 @@ static int erofs_readdir(struct file *f, struct dir_context *ctx)
 		if (nameoff < sizeof(struct erofs_dirent) ||
 		    nameoff >= PAGE_SIZE) {
 			errln("%s, invalid de[0].nameoff %u @ nid %llu",
-			      __func__, nameoff, EROFS_V(dir)->nid);
+			      __func__, nameoff, EROFS_I(dir)->nid);
 			err = -EFSCORRUPTED;
 			goto skip_this;
 		}
diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index 494b35e5830a..f6dfd0271261 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -11,7 +11,7 @@
 /* no locking */
 static int read_inode(struct inode *inode, void *data)
 {
-	struct erofs_vnode *vi = EROFS_V(inode);
+	struct erofs_inode *vi = EROFS_I(inode);
 	struct erofs_inode_compact *dic = data;
 	struct erofs_inode_extended *die;
 
@@ -140,7 +140,7 @@ static int read_inode(struct inode *inode, void *data)
 static int fill_inline_data(struct inode *inode, void *data,
 			    unsigned int m_pofs)
 {
-	struct erofs_vnode *vi = EROFS_V(inode);
+	struct erofs_inode *vi = EROFS_I(inode);
 	struct erofs_sb_info *sbi = EROFS_I_SB(inode);
 
 	/* should be tail-packing data inline */
@@ -178,7 +178,7 @@ static int fill_inline_data(struct inode *inode, void *data,
 static int fill_inode(struct inode *inode, int isdir)
 {
 	struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
-	struct erofs_vnode *vi = EROFS_V(inode);
+	struct erofs_inode *vi = EROFS_I(inode);
 	struct page *page;
 	void *data;
 	int err;
@@ -260,7 +260,7 @@ static int erofs_ilookup_test_actor(struct inode *inode, void *opaque)
 {
 	const erofs_nid_t nid = *(erofs_nid_t *)opaque;
 
-	return EROFS_V(inode)->nid == nid;
+	return EROFS_I(inode)->nid == nid;
 }
 
 static int erofs_iget_set_actor(struct inode *inode, void *opaque)
@@ -297,7 +297,7 @@ struct inode *erofs_iget(struct super_block *sb,
 
 	if (inode->i_state & I_NEW) {
 		int err;
-		struct erofs_vnode *vi = EROFS_V(inode);
+		struct erofs_inode *vi = EROFS_I(inode);
 
 		vi->nid = nid;
 
@@ -317,7 +317,7 @@ int erofs_getattr(const struct path *path, struct kstat *stat,
 {
 	struct inode *const inode = d_inode(path->dentry);
 
-	if (erofs_inode_is_data_compressed(EROFS_V(inode)->datalayout))
+	if (erofs_inode_is_data_compressed(EROFS_I(inode)->datalayout))
 		stat->attributes |= STATX_ATTR_COMPRESSED;
 
 	stat->attributes |= STATX_ATTR_IMMUTABLE;
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 0f5cbf0a7570..10497ee07cae 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -272,14 +272,14 @@ static inline erofs_off_t iloc(struct erofs_sb_info *sbi, erofs_nid_t nid)
 }
 
 /* atomic flag definitions */
-#define EROFS_V_EA_INITED_BIT	0
-#define EROFS_V_Z_INITED_BIT	1
+#define EROFS_I_EA_INITED_BIT	0
+#define EROFS_I_Z_INITED_BIT	1
 
 /* bitlock definitions (arranged in reverse order) */
-#define EROFS_V_BL_XATTR_BIT	(BITS_PER_LONG - 1)
-#define EROFS_V_BL_Z_BIT	(BITS_PER_LONG - 2)
+#define EROFS_I_BL_XATTR_BIT	(BITS_PER_LONG - 1)
+#define EROFS_I_BL_Z_BIT	(BITS_PER_LONG - 2)
 
-struct erofs_vnode {
+struct erofs_inode {
 	erofs_nid_t nid;
 
 	/* atomic flags (including bitlocks) */
@@ -307,8 +307,8 @@ struct erofs_vnode {
 	struct inode vfs_inode;
 };
 
-#define EROFS_V(ptr)	\
-	container_of(ptr, struct erofs_vnode, vfs_inode)
+#define EROFS_I(ptr)	\
+	container_of(ptr, struct erofs_inode, vfs_inode)
 
 static inline unsigned long inode_datablocks(struct inode *inode)
 {
diff --git a/fs/erofs/namei.c b/fs/erofs/namei.c
index c1068ad0535e..a6b6a4ab1403 100644
--- a/fs/erofs/namei.c
+++ b/fs/erofs/namei.c
@@ -117,7 +117,7 @@ static struct page *find_target_block_classic(struct inode *dir,
 				kunmap_atomic(de);
 				put_page(page);
 				errln("corrupted dir block %d @ nid %llu",
-				      mid, EROFS_V(dir)->nid);
+				      mid, EROFS_I(dir)->nid);
 				DBG_BUGON(1);
 				page = ERR_PTR(-EFSCORRUPTED);
 				goto out;
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 499dc7f5d0e6..3986be582dbb 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -18,27 +18,27 @@ static struct kmem_cache *erofs_inode_cachep __read_mostly;
 
 static void init_once(void *ptr)
 {
-	struct erofs_vnode *vi = ptr;
+	struct erofs_inode *vi = ptr;
 
 	inode_init_once(&vi->vfs_inode);
 }
 
 static struct inode *alloc_inode(struct super_block *sb)
 {
-	struct erofs_vnode *vi =
+	struct erofs_inode *vi =
 		kmem_cache_alloc(erofs_inode_cachep, GFP_KERNEL);
 
 	if (!vi)
 		return NULL;
 
 	/* zero out everything except vfs_inode */
-	memset(vi, 0, offsetof(struct erofs_vnode, vfs_inode));
+	memset(vi, 0, offsetof(struct erofs_inode, vfs_inode));
 	return &vi->vfs_inode;
 }
 
 static void free_inode(struct inode *inode)
 {
-	struct erofs_vnode *vi = EROFS_V(inode);
+	struct erofs_inode *vi = EROFS_I(inode);
 
 	/* be careful RCU symlink path (see ext4_inode_info->i_data)! */
 	if (is_inode_fast_symlink(inode))
@@ -517,7 +517,7 @@ static int __init erofs_module_init(void)
 	infoln("initializing erofs " EROFS_VERSION);
 
 	erofs_inode_cachep = kmem_cache_create("erofs_inode",
-					       sizeof(struct erofs_vnode), 0,
+					       sizeof(struct erofs_inode), 0,
 					       SLAB_RECLAIM_ACCOUNT,
 					       init_once);
 	if (!erofs_inode_cachep) {
diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c
index 620cbc15f4d0..d5b7fe0bee45 100644
--- a/fs/erofs/xattr.c
+++ b/fs/erofs/xattr.c
@@ -38,7 +38,7 @@ static inline void xattr_iter_end_final(struct xattr_iter *it)
 
 static int init_inode_xattrs(struct inode *inode)
 {
-	struct erofs_vnode *const vi = EROFS_V(inode);
+	struct erofs_inode *const vi = EROFS_I(inode);
 	struct xattr_iter it;
 	unsigned int i;
 	struct erofs_xattr_ibody_header *ih;
@@ -48,14 +48,14 @@ static int init_inode_xattrs(struct inode *inode)
 	int ret = 0;
 
 	/* the most case is that xattrs of this inode are initialized. */
-	if (test_bit(EROFS_V_EA_INITED_BIT, &vi->flags))
+	if (test_bit(EROFS_I_EA_INITED_BIT, &vi->flags))
 		return 0;
 
-	if (wait_on_bit_lock(&vi->flags, EROFS_V_BL_XATTR_BIT, TASK_KILLABLE))
+	if (wait_on_bit_lock(&vi->flags, EROFS_I_BL_XATTR_BIT, TASK_KILLABLE))
 		return -ERESTARTSYS;
 
 	/* someone has initialized xattrs for us? */
-	if (test_bit(EROFS_V_EA_INITED_BIT, &vi->flags))
+	if (test_bit(EROFS_I_EA_INITED_BIT, &vi->flags))
 		goto out_unlock;
 
 	/*
@@ -136,10 +136,10 @@ static int init_inode_xattrs(struct inode *inode)
 	}
 	xattr_iter_end(&it, atomic_map);
 
-	set_bit(EROFS_V_EA_INITED_BIT, &vi->flags);
+	set_bit(EROFS_I_EA_INITED_BIT, &vi->flags);
 
 out_unlock:
-	clear_and_wake_up_bit(EROFS_V_BL_XATTR_BIT, &vi->flags);
+	clear_and_wake_up_bit(EROFS_I_BL_XATTR_BIT, &vi->flags);
 	return ret;
 }
 
@@ -184,7 +184,7 @@ static inline int xattr_iter_fixup(struct xattr_iter *it)
 static int inline_xattr_iter_begin(struct xattr_iter *it,
 				   struct inode *inode)
 {
-	struct erofs_vnode *const vi = EROFS_V(inode);
+	struct erofs_inode *const vi = EROFS_I(inode);
 	struct erofs_sb_info *const sbi = EROFS_SB(inode->i_sb);
 	unsigned int xattr_header_sz, inline_xattr_ofs;
 
@@ -385,7 +385,7 @@ static int inline_getxattr(struct inode *inode, struct getxattr_iter *it)
 
 static int shared_getxattr(struct inode *inode, struct getxattr_iter *it)
 {
-	struct erofs_vnode *const vi = EROFS_V(inode);
+	struct erofs_inode *const vi = EROFS_I(inode);
 	struct super_block *const sb = inode->i_sb;
 	struct erofs_sb_info *const sbi = EROFS_SB(sb);
 	unsigned int i;
@@ -608,7 +608,7 @@ static int inline_listxattr(struct listxattr_iter *it)
 static int shared_listxattr(struct listxattr_iter *it)
 {
 	struct inode *const inode = d_inode(it->dentry);
-	struct erofs_vnode *const vi = EROFS_V(inode);
+	struct erofs_inode *const vi = EROFS_I(inode);
 	struct super_block *const sb = inode->i_sb;
 	struct erofs_sb_info *const sbi = EROFS_SB(sb);
 	unsigned int i;
diff --git a/fs/erofs/xattr.h b/fs/erofs/xattr.h
index c5ca47d814dd..3585b84d2f20 100644
--- a/fs/erofs/xattr.h
+++ b/fs/erofs/xattr.h
@@ -16,8 +16,8 @@
 
 static inline unsigned int inlinexattr_header_size(struct inode *inode)
 {
-	return sizeof(struct erofs_xattr_ibody_header)
-		+ sizeof(u32) * EROFS_V(inode)->xattr_shared_count;
+	return sizeof(struct erofs_xattr_ibody_header) +
+		sizeof(u32) * EROFS_I(inode)->xattr_shared_count;
 }
 
 static inline erofs_blk_t xattrblock_addr(struct erofs_sb_info *sbi,
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index 653bde0a619a..f06a2fad7af2 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -421,7 +421,7 @@ static struct z_erofs_collection *clregister(struct z_erofs_collector *clt,
 	else
 		pcl->algorithmformat = Z_EROFS_COMPRESSION_SHIFTED;
 
-	pcl->clusterbits = EROFS_V(inode)->z_physical_clusterbits[0];
+	pcl->clusterbits = EROFS_I(inode)->z_physical_clusterbits[0];
 	pcl->clusterbits -= PAGE_SHIFT;
 
 	/* new pclusters should be claimed as type 1, primary and followed */
@@ -1404,12 +1404,9 @@ static int z_erofs_vle_normalaccess_readpages(struct file *filp,
 		head = (void *)page_private(page);
 
 		err = z_erofs_do_read_page(&f, page, &pagepool);
-		if (err) {
-			struct erofs_vnode *vi = EROFS_V(inode);
-
+		if (err)
 			errln("%s, readahead error at page %lu of nid %llu",
-			      __func__, page->index, vi->nid);
-		}
+			      __func__, page->index, EROFS_I(inode)->nid);
 		put_page(page);
 	}
 
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index 6a06fb80ef3f..30a5171637d7 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -10,7 +10,7 @@
 
 int z_erofs_fill_inode(struct inode *inode)
 {
-	struct erofs_vnode *const vi = EROFS_V(inode);
+	struct erofs_inode *const vi = EROFS_I(inode);
 
 	if (vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY) {
 		vi->z_advise = 0;
@@ -19,7 +19,7 @@ int z_erofs_fill_inode(struct inode *inode)
 		vi->z_logical_clusterbits = LOG_BLOCK_SIZE;
 		vi->z_physical_clusterbits[0] = vi->z_logical_clusterbits;
 		vi->z_physical_clusterbits[1] = vi->z_logical_clusterbits;
-		set_bit(EROFS_V_Z_INITED_BIT, &vi->flags);
+		set_bit(EROFS_I_Z_INITED_BIT, &vi->flags);
 	}
 
 	inode->i_mapping->a_ops = &z_erofs_vle_normalaccess_aops;
@@ -28,7 +28,7 @@ int z_erofs_fill_inode(struct inode *inode)
 
 static int fill_inode_lazy(struct inode *inode)
 {
-	struct erofs_vnode *const vi = EROFS_V(inode);
+	struct erofs_inode *const vi = EROFS_I(inode);
 	struct super_block *const sb = inode->i_sb;
 	int err;
 	erofs_off_t pos;
@@ -36,14 +36,14 @@ static int fill_inode_lazy(struct inode *inode)
 	void *kaddr;
 	struct z_erofs_map_header *h;
 
-	if (test_bit(EROFS_V_Z_INITED_BIT, &vi->flags))
+	if (test_bit(EROFS_I_Z_INITED_BIT, &vi->flags))
 		return 0;
 
-	if (wait_on_bit_lock(&vi->flags, EROFS_V_BL_Z_BIT, TASK_KILLABLE))
+	if (wait_on_bit_lock(&vi->flags, EROFS_I_BL_Z_BIT, TASK_KILLABLE))
 		return -ERESTARTSYS;
 
 	err = 0;
-	if (test_bit(EROFS_V_Z_INITED_BIT, &vi->flags))
+	if (test_bit(EROFS_I_Z_INITED_BIT, &vi->flags))
 		goto out_unlock;
 
 	DBG_BUGON(vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY);
@@ -83,13 +83,13 @@ static int fill_inode_lazy(struct inode *inode)
 
 	vi->z_physical_clusterbits[1] = vi->z_logical_clusterbits +
 					((h->h_clusterbits >> 5) & 7);
-	set_bit(EROFS_V_Z_INITED_BIT, &vi->flags);
+	set_bit(EROFS_I_Z_INITED_BIT, &vi->flags);
 unmap_done:
 	kunmap_atomic(kaddr);
 	unlock_page(page);
 	put_page(page);
 out_unlock:
-	clear_and_wake_up_bit(EROFS_V_BL_Z_BIT, &vi->flags);
+	clear_and_wake_up_bit(EROFS_I_BL_Z_BIT, &vi->flags);
 	return err;
 }
 
@@ -142,7 +142,7 @@ static int vle_legacy_load_cluster_from_disk(struct z_erofs_maprecorder *m,
 					     unsigned long lcn)
 {
 	struct inode *const inode = m->inode;
-	struct erofs_vnode *const vi = EROFS_V(inode);
+	struct erofs_inode *const vi = EROFS_I(inode);
 	const erofs_off_t ibase = iloc(EROFS_I_SB(inode), vi->nid);
 	const erofs_off_t pos =
 		Z_EROFS_VLE_LEGACY_INDEX_ALIGN(ibase + vi->inode_isize +
@@ -196,7 +196,7 @@ static int unpack_compacted_index(struct z_erofs_maprecorder *m,
 				  unsigned int amortizedshift,
 				  unsigned int eofs)
 {
-	struct erofs_vnode *const vi = EROFS_V(m->inode);
+	struct erofs_inode *const vi = EROFS_I(m->inode);
 	const unsigned int lclusterbits = vi->z_logical_clusterbits;
 	const unsigned int lomask = (1 << lclusterbits) - 1;
 	unsigned int vcnt, base, lo, encodebits, nblk;
@@ -260,7 +260,7 @@ static int compacted_load_cluster_from_disk(struct z_erofs_maprecorder *m,
 					    unsigned long lcn)
 {
 	struct inode *const inode = m->inode;
-	struct erofs_vnode *const vi = EROFS_V(inode);
+	struct erofs_inode *const vi = EROFS_I(inode);
 	const unsigned int lclusterbits = vi->z_logical_clusterbits;
 	const erofs_off_t ebase = ALIGN(iloc(EROFS_I_SB(inode), vi->nid) +
 					vi->inode_isize + vi->xattr_isize, 8) +
@@ -314,7 +314,7 @@ static int compacted_load_cluster_from_disk(struct z_erofs_maprecorder *m,
 static int vle_load_cluster_from_disk(struct z_erofs_maprecorder *m,
 				      unsigned int lcn)
 {
-	const unsigned int datamode = EROFS_V(m->inode)->datalayout;
+	const unsigned int datamode = EROFS_I(m->inode)->datalayout;
 
 	if (datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY)
 		return vle_legacy_load_cluster_from_disk(m, lcn);
@@ -328,7 +328,7 @@ static int vle_load_cluster_from_disk(struct z_erofs_maprecorder *m,
 static int vle_extent_lookback(struct z_erofs_maprecorder *m,
 			       unsigned int lookback_distance)
 {
-	struct erofs_vnode *const vi = EROFS_V(m->inode);
+	struct erofs_inode *const vi = EROFS_I(m->inode);
 	struct erofs_map_blocks *const map = m->map;
 	const unsigned int lclusterbits = vi->z_logical_clusterbits;
 	unsigned long lcn = m->lcn;
@@ -374,7 +374,7 @@ int z_erofs_map_blocks_iter(struct inode *inode,
 			    struct erofs_map_blocks *map,
 			    int flags)
 {
-	struct erofs_vnode *const vi = EROFS_V(inode);
+	struct erofs_inode *const vi = EROFS_I(inode);
 	struct z_erofs_maprecorder m = {
 		.inode = inode,
 		.map = map,
diff --git a/include/trace/events/erofs.h b/include/trace/events/erofs.h
index d239f39cbc8c..27f5caa6299a 100644
--- a/include/trace/events/erofs.h
+++ b/include/trace/events/erofs.h
@@ -41,7 +41,7 @@ TRACE_EVENT(erofs_lookup,
 
 	TP_fast_assign(
 		__entry->dev	= dir->i_sb->s_dev;
-		__entry->nid	= EROFS_V(dir)->nid;
+		__entry->nid	= EROFS_I(dir)->nid;
 		__entry->name	= dentry->d_name.name;
 		__entry->flags	= flags;
 	),
@@ -66,7 +66,7 @@ TRACE_EVENT(erofs_fill_inode,
 
 	TP_fast_assign(
 		__entry->dev		= inode->i_sb->s_dev;
-		__entry->nid		= EROFS_V(inode)->nid;
+		__entry->nid		= EROFS_I(inode)->nid;
 		__entry->blkaddr	= erofs_blknr(iloc(EROFS_I_SB(inode), __entry->nid));
 		__entry->ofs		= erofs_blkoff(iloc(EROFS_I_SB(inode), __entry->nid));
 		__entry->isdir		= isdir;
@@ -95,7 +95,7 @@ TRACE_EVENT(erofs_readpage,
 
 	TP_fast_assign(
 		__entry->dev	= page->mapping->host->i_sb->s_dev;
-		__entry->nid	= EROFS_V(page->mapping->host)->nid;
+		__entry->nid	= EROFS_I(page->mapping->host)->nid;
 		__entry->dir	= S_ISDIR(page->mapping->host->i_mode);
 		__entry->index	= page->index;
 		__entry->uptodate = PageUptodate(page);
@@ -128,7 +128,7 @@ TRACE_EVENT(erofs_readpages,
 
 	TP_fast_assign(
 		__entry->dev	= inode->i_sb->s_dev;
-		__entry->nid	= EROFS_V(inode)->nid;
+		__entry->nid	= EROFS_I(inode)->nid;
 		__entry->start	= page->index;
 		__entry->nrpage	= nrpage;
 		__entry->raw	= raw;
@@ -157,7 +157,7 @@ DECLARE_EVENT_CLASS(erofs__map_blocks_enter,
 
 	TP_fast_assign(
 		__entry->dev    = inode->i_sb->s_dev;
-		__entry->nid    = EROFS_V(inode)->nid;
+		__entry->nid    = EROFS_I(inode)->nid;
 		__entry->la	= map->m_la;
 		__entry->llen	= map->m_llen;
 		__entry->flags	= flags;
@@ -203,7 +203,7 @@ DECLARE_EVENT_CLASS(erofs__map_blocks_exit,
 
 	TP_fast_assign(
 		__entry->dev    = inode->i_sb->s_dev;
-		__entry->nid    = EROFS_V(inode)->nid;
+		__entry->nid    = EROFS_I(inode)->nid;
 		__entry->flags	= flags;
 		__entry->la	= map->m_la;
 		__entry->pa	= map->m_pa;
@@ -247,7 +247,7 @@ TRACE_EVENT(erofs_destroy_inode,
 
 	TP_fast_assign(
 		__entry->dev	= inode->i_sb->s_dev;
-		__entry->nid	= EROFS_V(inode)->nid;
+		__entry->nid	= EROFS_I(inode)->nid;
 	),
 
 	TP_printk("dev = (%d,%d), nid = %llu", show_dev_nid(__entry))
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v2 10/25] erofs: update erofs_fs.h comments
  2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
                       ` (8 preceding siblings ...)
  2019-09-04  2:08     ` [PATCH v2 09/25] erofs: use erofs_inode naming Gao Xiang
@ 2019-09-04  2:08     ` Gao Xiang
  2019-09-04  2:08     ` [PATCH v2 11/25] erofs: update comments in inode.c Gao Xiang
                       ` (16 subsequent siblings)
  26 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-04  2:08 UTC (permalink / raw)
  To: Chao Yu, Greg Kroah-Hartman, Christoph Hellwig, devel
  Cc: linux-fsdevel, linux-erofs, Chao Yu, Miao Xie, Gao Xiang

As Christoph said [1] [2], update it now.

[1] https://lore.kernel.org/r/20190902124521.GA22153@infradead.org/
[2] https://lore.kernel.org/r/20190902120548.GB15931@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/erofs_fs.h | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
index 18689e916e94..b1ee5654750d 100644
--- a/fs/erofs/erofs_fs.h
+++ b/fs/erofs/erofs_fs.h
@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0-only OR Apache-2.0 */
 /*
+ * EROFS (Enhanced ROM File System) on-disk format definition
+ *
  * Copyright (C) 2017-2018 HUAWEI, Inc.
  *             http://www.huawei.com/
  * Created by Gao Xiang <gaoxiang25@huawei.com>
@@ -7,7 +9,6 @@
 #ifndef __EROFS_FS_H
 #define __EROFS_FS_H
 
-/* Enhanced(Extended) ROM File System */
 #define EROFS_SUPER_OFFSET      1024
 
 /*
@@ -41,7 +42,7 @@ struct erofs_super_block {
 };
 
 /*
- * erofs inode datalayout:
+ * erofs inode datalayout (i_format in on-disk inode):
  * 0 - inode plain without inline data A:
  * inode, [xattrs], ... | ... | no-holed data
  * 1 - inode VLE compression B (legacy):
@@ -187,7 +188,7 @@ static inline unsigned int erofs_xattr_entry_size(struct erofs_xattr_entry *e)
 				 e->e_name_len + le16_to_cpu(e->e_value_size));
 }
 
-/* available compression algorithm types */
+/* available compression algorithm types (for h_algorithmtype) */
 enum {
 	Z_EROFS_COMPRESSION_LZ4	= 0,
 	Z_EROFS_COMPRESSION_MAX
@@ -222,7 +223,7 @@ struct z_erofs_map_header {
 #define Z_EROFS_VLE_LEGACY_HEADER_PADDING       8
 
 /*
- * Z_EROFS Variable-sized Logical Extent cluster type:
+ * Fixed-sized output compression ondisk Logical Extent cluster type:
  *    0 - literal (uncompressed) cluster
  *    1 - compressed cluster (for the head logical cluster)
  *    2 - compressed cluster (for the other logical clusters)
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v2 11/25] erofs: update comments in inode.c
  2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
                       ` (9 preceding siblings ...)
  2019-09-04  2:08     ` [PATCH v2 10/25] erofs: update erofs_fs.h comments Gao Xiang
@ 2019-09-04  2:08     ` Gao Xiang
  2019-09-04  2:08     ` [PATCH v2 12/25] erofs: better erofs symlink stuffs Gao Xiang
                       ` (15 subsequent siblings)
  26 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-04  2:08 UTC (permalink / raw)
  To: Chao Yu, Greg Kroah-Hartman, Christoph Hellwig, devel
  Cc: linux-fsdevel, linux-erofs, Chao Yu, Miao Xie, Gao Xiang

As Christoph suggested [1], update them all.

[1] https://lore.kernel.org/r/20190829102426.GE20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/inode.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index f6dfd0271261..a42f5fc14df9 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -147,7 +147,7 @@ static int fill_inline_data(struct inode *inode, void *data,
 	if (vi->datalayout != EROFS_INODE_FLAT_INLINE)
 		return 0;
 
-	/* fast symlink (following ext4) */
+	/* fast symlink */
 	if (S_ISLNK(inode->i_mode) && inode->i_size < PAGE_SIZE) {
 		char *lnk = erofs_kmalloc(sbi, inode->i_size + 1, GFP_KERNEL);
 
@@ -156,7 +156,7 @@ static int fill_inline_data(struct inode *inode, void *data,
 
 		m_pofs += vi->inode_isize + vi->xattr_isize;
 
-		/* inline symlink data shouldn't across page boundary as well */
+		/* inline symlink data shouldn't cross page boundary as well */
 		if (m_pofs + inode->i_size > PAGE_SIZE) {
 			kfree(lnk);
 			errln("inline data cross block boundary @ nid %llu",
@@ -165,7 +165,6 @@ static int fill_inline_data(struct inode *inode, void *data,
 			return -EFSCORRUPTED;
 		}
 
-		/* get in-page inline data */
 		memcpy(lnk, data + m_pofs, inode->i_size);
 		lnk[inode->i_size] = '\0';
 
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v2 12/25] erofs: better erofs symlink stuffs
  2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
                       ` (10 preceding siblings ...)
  2019-09-04  2:08     ` [PATCH v2 11/25] erofs: update comments in inode.c Gao Xiang
@ 2019-09-04  2:08     ` Gao Xiang
  2019-09-04  2:09     ` [PATCH v2 13/25] erofs: use dsb instead of layout for ondisk super_block Gao Xiang
                       ` (14 subsequent siblings)
  26 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-04  2:08 UTC (permalink / raw)
  To: Chao Yu, Greg Kroah-Hartman, Christoph Hellwig, devel
  Cc: linux-fsdevel, linux-erofs, Chao Yu, Miao Xie, Gao Xiang

Fix as Christoph suggested [1] [2], "remove is_inode_fast_symlink
and just opencode it in the few places using it"

and
"Please just set the ops directly instead of obsfucating that in
a single caller, single line inline function.  And please set it
instead of the normal symlink iops in the same place where you
also set those."

[1] https://lore.kernel.org/r/20190830163910.GB29603@infradead.org/
[2] https://lore.kernel.org/r/20190829102426.GE20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/inode.c    | 68 ++++++++++++++++++---------------------------
 fs/erofs/internal.h | 10 -------
 fs/erofs/super.c    |  5 ++--
 3 files changed, 29 insertions(+), 54 deletions(-)

diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index a42f5fc14df9..770f3259c862 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -127,50 +127,39 @@ static int read_inode(struct inode *inode, void *data)
 	return -EFSCORRUPTED;
 }
 
-/*
- * try_lock can be required since locking order is:
- *   file data(fs_inode)
- *        meta(bd_inode)
- * but the majority of the callers is "iget",
- * in that case we are pretty sure no deadlock since
- * no data operations exist. However I tend to
- * try_lock since it takes no much overhead and
- * will success immediately.
- */
-static int fill_inline_data(struct inode *inode, void *data,
-			    unsigned int m_pofs)
+static int erofs_fill_symlink(struct inode *inode, void *data,
+			      unsigned int m_pofs)
 {
 	struct erofs_inode *vi = EROFS_I(inode);
 	struct erofs_sb_info *sbi = EROFS_I_SB(inode);
+	char *lnk;
 
-	/* should be tail-packing data inline */
-	if (vi->datalayout != EROFS_INODE_FLAT_INLINE)
+	/* if it cannot be handled with fast symlink scheme */
+	if (vi->datalayout != EROFS_INODE_FLAT_INLINE ||
+	    inode->i_size >= PAGE_SIZE) {
+		inode->i_op = &erofs_symlink_iops;
 		return 0;
+	}
 
-	/* fast symlink */
-	if (S_ISLNK(inode->i_mode) && inode->i_size < PAGE_SIZE) {
-		char *lnk = erofs_kmalloc(sbi, inode->i_size + 1, GFP_KERNEL);
-
-		if (!lnk)
-			return -ENOMEM;
-
-		m_pofs += vi->inode_isize + vi->xattr_isize;
+	lnk = erofs_kmalloc(sbi, inode->i_size + 1, GFP_KERNEL);
+	if (!lnk)
+		return -ENOMEM;
 
-		/* inline symlink data shouldn't cross page boundary as well */
-		if (m_pofs + inode->i_size > PAGE_SIZE) {
-			kfree(lnk);
-			errln("inline data cross block boundary @ nid %llu",
-			      vi->nid);
-			DBG_BUGON(1);
-			return -EFSCORRUPTED;
-		}
+	m_pofs += vi->inode_isize + vi->xattr_isize;
+	/* inline symlink data shouldn't cross page boundary as well */
+	if (m_pofs + inode->i_size > PAGE_SIZE) {
+		kfree(lnk);
+		errln("inline data cross block boundary @ nid %llu",
+		      vi->nid);
+		DBG_BUGON(1);
+		return -EFSCORRUPTED;
+	}
 
-		memcpy(lnk, data + m_pofs, inode->i_size);
-		lnk[inode->i_size] = '\0';
+	memcpy(lnk, data + m_pofs, inode->i_size);
+	lnk[inode->i_size] = '\0';
 
-		inode->i_link = lnk;
-		set_inode_fast_symlink(inode);
-	}
+	inode->i_link = lnk;
+	inode->i_op = &erofs_fast_symlink_iops;
 	return 0;
 }
 
@@ -217,8 +206,9 @@ static int fill_inode(struct inode *inode, int isdir)
 			inode->i_fop = &erofs_dir_fops;
 			break;
 		case S_IFLNK:
-			/* by default, page_get_link is used for symlink */
-			inode->i_op = &erofs_symlink_iops;
+			err = erofs_fill_symlink(inode, data, ofs);
+			if (err)
+				goto out_unlock;
 			inode_nohighmem(inode);
 			break;
 		case S_IFCHR:
@@ -237,11 +227,7 @@ static int fill_inode(struct inode *inode, int isdir)
 			err = z_erofs_fill_inode(inode);
 			goto out_unlock;
 		}
-
 		inode->i_mapping->a_ops = &erofs_raw_access_aops;
-
-		/* fill last page if inline data is available */
-		err = fill_inline_data(inode, data, ofs);
 	}
 
 out_unlock:
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 10497ee07cae..cc1ea98c5c89 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -479,16 +479,6 @@ extern const struct inode_operations erofs_generic_iops;
 extern const struct inode_operations erofs_symlink_iops;
 extern const struct inode_operations erofs_fast_symlink_iops;
 
-static inline void set_inode_fast_symlink(struct inode *inode)
-{
-	inode->i_op = &erofs_fast_symlink_iops;
-}
-
-static inline bool is_inode_fast_symlink(struct inode *inode)
-{
-	return inode->i_op == &erofs_fast_symlink_iops;
-}
-
 struct inode *erofs_iget(struct super_block *sb, erofs_nid_t nid, bool dir);
 int erofs_getattr(const struct path *path, struct kstat *stat,
 		  u32 request_mask, unsigned int query_flags);
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 3986be582dbb..b8b0e35f6621 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -40,10 +40,9 @@ static void free_inode(struct inode *inode)
 {
 	struct erofs_inode *vi = EROFS_I(inode);
 
-	/* be careful RCU symlink path (see ext4_inode_info->i_data)! */
-	if (is_inode_fast_symlink(inode))
+	/* be careful of RCU symlink path */
+	if (inode->i_op == &erofs_fast_symlink_iops)
 		kfree(inode->i_link);
-
 	kfree(vi->xattr_shared_xattrs);
 
 	kmem_cache_free(erofs_inode_cachep, vi);
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v2 13/25] erofs: use dsb instead of layout for ondisk super_block
  2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
                       ` (11 preceding siblings ...)
  2019-09-04  2:08     ` [PATCH v2 12/25] erofs: better erofs symlink stuffs Gao Xiang
@ 2019-09-04  2:09     ` Gao Xiang
  2019-09-04  2:09     ` [PATCH v2 14/25] erofs: kill verbose debug info in erofs_fill_super Gao Xiang
                       ` (13 subsequent siblings)
  26 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-04  2:09 UTC (permalink / raw)
  To: Chao Yu, Greg Kroah-Hartman, Christoph Hellwig, devel
  Cc: linux-fsdevel, linux-erofs, Chao Yu, Miao Xie, Gao Xiang

As Christoph pointed out [1], "Why is the variable name
for the on-disk subperblock layout? We usually still
calls this something with sb in the name, e.g. dsb.
for disksuper block. " Let's fix it.

[1] https://lore.kernel.org/r/20190829101545.GC20598@infradead.org/
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/super.c | 35 +++++++++++++++++------------------
 1 file changed, 17 insertions(+), 18 deletions(-)

diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index b8b0e35f6621..63cb17a4073b 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -49,9 +49,9 @@ static void free_inode(struct inode *inode)
 }
 
 static bool check_layout_compatibility(struct super_block *sb,
-				       struct erofs_super_block *layout)
+				       struct erofs_super_block *dsb)
 {
-	const unsigned int feature = le32_to_cpu(layout->feature_incompat);
+	const unsigned int feature = le32_to_cpu(dsb->feature_incompat);
 
 	EROFS_SB(sb)->feature_incompat = feature;
 
@@ -68,7 +68,7 @@ static int superblock_read(struct super_block *sb)
 {
 	struct erofs_sb_info *sbi;
 	struct buffer_head *bh;
-	struct erofs_super_block *layout;
+	struct erofs_super_block *dsb;
 	unsigned int blkszbits;
 	int ret;
 
@@ -80,16 +80,15 @@ static int superblock_read(struct super_block *sb)
 	}
 
 	sbi = EROFS_SB(sb);
-	layout = (struct erofs_super_block *)((u8 *)bh->b_data
-		 + EROFS_SUPER_OFFSET);
+	dsb = (struct erofs_super_block *)(bh->b_data + EROFS_SUPER_OFFSET);
 
 	ret = -EINVAL;
-	if (le32_to_cpu(layout->magic) != EROFS_SUPER_MAGIC_V1) {
+	if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) {
 		errln("cannot find valid erofs superblock");
 		goto out;
 	}
 
-	blkszbits = layout->blkszbits;
+	blkszbits = dsb->blkszbits;
 	/* 9(512 bytes) + LOG_SECTORS_PER_BLOCK == LOG_BLOCK_SIZE */
 	if (blkszbits != LOG_BLOCK_SIZE) {
 		errln("blksize %u isn't supported on this platform",
@@ -97,25 +96,25 @@ static int superblock_read(struct super_block *sb)
 		goto out;
 	}
 
-	if (!check_layout_compatibility(sb, layout))
+	if (!check_layout_compatibility(sb, dsb))
 		goto out;
 
-	sbi->blocks = le32_to_cpu(layout->blocks);
-	sbi->meta_blkaddr = le32_to_cpu(layout->meta_blkaddr);
+	sbi->blocks = le32_to_cpu(dsb->blocks);
+	sbi->meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr);
 #ifdef CONFIG_EROFS_FS_XATTR
-	sbi->xattr_blkaddr = le32_to_cpu(layout->xattr_blkaddr);
+	sbi->xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr);
 #endif
 	sbi->islotbits = ilog2(sizeof(struct erofs_inode_compact));
-	sbi->root_nid = le16_to_cpu(layout->root_nid);
-	sbi->inos = le64_to_cpu(layout->inos);
+	sbi->root_nid = le16_to_cpu(dsb->root_nid);
+	sbi->inos = le64_to_cpu(dsb->inos);
 
-	sbi->build_time = le64_to_cpu(layout->build_time);
-	sbi->build_time_nsec = le32_to_cpu(layout->build_time_nsec);
+	sbi->build_time = le64_to_cpu(dsb->build_time);
+	sbi->build_time_nsec = le32_to_cpu(dsb->build_time_nsec);
 
-	memcpy(&sb->s_uuid, layout->uuid, sizeof(layout->uuid));
+	memcpy(&sb->s_uuid, dsb->uuid, sizeof(dsb->uuid));
 
-	ret = strscpy(sbi->volume_name, layout->volume_name,
-		      sizeof(layout->volume_name));
+	ret = strscpy(sbi->volume_name, dsb->volume_name,
+		      sizeof(dsb->volume_name));
 	if (ret < 0) {	/* -E2BIG */
 		errln("bad volume name without NIL terminator");
 		ret = -EFSCORRUPTED;
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v2 14/25] erofs: kill verbose debug info in erofs_fill_super
  2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
                       ` (12 preceding siblings ...)
  2019-09-04  2:09     ` [PATCH v2 13/25] erofs: use dsb instead of layout for ondisk super_block Gao Xiang
@ 2019-09-04  2:09     ` Gao Xiang
  2019-09-04  2:09     ` [PATCH v2 15/25] erofs: localize erofs_grab_bio() Gao Xiang
                       ` (12 subsequent siblings)
  26 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-04  2:09 UTC (permalink / raw)
  To: Chao Yu, Greg Kroah-Hartman, Christoph Hellwig, devel
  Cc: linux-fsdevel, linux-erofs, Chao Yu, Miao Xie, Gao Xiang

As Christoph said [1], "That is some very verbose
debug info.  We usually don't add that and let
people trace the function instead. "

[1] https://lore.kernel.org/r/20190829101545.GC20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/super.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 63cb17a4073b..b64d69f18270 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -384,9 +384,6 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
 	struct erofs_sb_info *sbi;
 	int err;
 
-	infoln("fill_super, device -> %s", sb->s_id);
-	infoln("options -> %s", (char *)data);
-
 	sb->s_magic = EROFS_SUPER_MAGIC;
 
 	if (!sb_set_blocksize(sb, EROFS_BLKSIZ)) {
@@ -419,9 +416,6 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
 	if (err)
 		return err;
 
-	if (!silent)
-		infoln("root inode @ nid %llu", ROOT_NID(sbi));
-
 	if (test_opt(sbi, POSIX_ACL))
 		sb->s_flags |= SB_POSIXACL;
 	else
@@ -454,7 +448,8 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
 		return err;
 
 	if (!silent)
-		infoln("mounted on %s with opts: %s.", sb->s_id, (char *)data);
+		infoln("mounted on %s with opts: %s, root inode @ nid %llu.",
+		       sb->s_id, (char *)data, ROOT_NID(sbi));
 	return 0;
 }
 
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v2 15/25] erofs: localize erofs_grab_bio()
  2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
                       ` (13 preceding siblings ...)
  2019-09-04  2:09     ` [PATCH v2 14/25] erofs: kill verbose debug info in erofs_fill_super Gao Xiang
@ 2019-09-04  2:09     ` Gao Xiang
  2019-09-04  2:09     ` [PATCH v2 16/25] erofs: kill prio and nofail of erofs_get_meta_page() Gao Xiang
                       ` (11 subsequent siblings)
  26 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-04  2:09 UTC (permalink / raw)
  To: Chao Yu, Greg Kroah-Hartman, Christoph Hellwig, devel
  Cc: linux-fsdevel, linux-erofs, Chao Yu, Miao Xie, Gao Xiang

As Christoph pointed out [1], "erofs_grab_bio tries to
handle a bio_alloc failure, except that the function will
not actually fail due the mempool backing it."

Sorry about useless code, fix it now and
localize erofs_grab_bio [2].

[1] https://lore.kernel.org/r/20190830162812.GA10694@infradead.org/
[2] https://lore.kernel.org/r/20190902122016.GL15931@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/data.c     | 28 +++++++++++++++-------------
 fs/erofs/internal.h | 29 -----------------------------
 fs/erofs/zdata.c    | 10 +++++++---
 3 files changed, 22 insertions(+), 45 deletions(-)

diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index be11b5ea9d2e..0136ea117934 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -38,6 +38,19 @@ static inline void read_endio(struct bio *bio)
 	bio_put(bio);
 }
 
+static struct bio *erofs_grab_raw_bio(struct super_block *sb,
+				      erofs_blk_t blkaddr,
+				      unsigned int nr_pages)
+{
+	struct bio *bio = bio_alloc(GFP_NOIO, nr_pages);
+
+	bio->bi_end_io = read_endio;
+	bio_set_dev(bio, sb->s_bdev);
+	bio->bi_iter.bi_sector = (sector_t)blkaddr << LOG_SECTORS_PER_BLOCK;
+	bio->bi_private = sb;
+	return bio;
+}
+
 /* prio -- true is used for dir */
 struct page *__erofs_get_meta_page(struct super_block *sb,
 				   erofs_blk_t blkaddr, bool prio, bool nofail)
@@ -62,12 +75,7 @@ struct page *__erofs_get_meta_page(struct super_block *sb,
 	if (!PageUptodate(page)) {
 		struct bio *bio;
 
-		bio = erofs_grab_bio(sb, blkaddr, 1, sb, read_endio, nofail);
-		if (IS_ERR(bio)) {
-			DBG_BUGON(nofail);
-			err = PTR_ERR(bio);
-			goto err_out;
-		}
+		bio = erofs_grab_raw_bio(sb, blkaddr, 1);
 
 		if (bio_add_page(bio, page, PAGE_SIZE, 0) != PAGE_SIZE) {
 			err = -EFAULT;
@@ -276,13 +284,7 @@ static inline struct bio *erofs_read_raw_page(struct bio *bio,
 		if (nblocks > BIO_MAX_PAGES)
 			nblocks = BIO_MAX_PAGES;
 
-		bio = erofs_grab_bio(sb, blknr, nblocks, sb,
-				     read_endio, false);
-		if (IS_ERR(bio)) {
-			err = PTR_ERR(bio);
-			bio = NULL;
-			goto err_out;
-		}
+		bio = erofs_grab_raw_bio(sb, blknr, nblocks);
 	}
 
 	err = bio_add_page(bio, page, PAGE_SIZE, 0);
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index cc1ea98c5c89..000ea92b36a3 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -411,35 +411,6 @@ static inline int z_erofs_map_blocks_iter(struct inode *inode,
 #endif	/* !CONFIG_EROFS_FS_ZIP */
 
 /* data.c */
-static inline struct bio *erofs_grab_bio(struct super_block *sb,
-					 erofs_blk_t blkaddr,
-					 unsigned int nr_pages,
-					 void *bi_private, bio_end_io_t endio,
-					 bool nofail)
-{
-	const gfp_t gfp = GFP_NOIO;
-	struct bio *bio;
-
-	do {
-		if (nr_pages == 1) {
-			bio = bio_alloc(gfp | (nofail ? __GFP_NOFAIL : 0), 1);
-			if (!bio) {
-				DBG_BUGON(nofail);
-				return ERR_PTR(-ENOMEM);
-			}
-			break;
-		}
-		bio = bio_alloc(gfp, nr_pages);
-		nr_pages /= 2;
-	} while (!bio);
-
-	bio->bi_end_io = endio;
-	bio_set_dev(bio, sb->s_bdev);
-	bio->bi_iter.bi_sector = (sector_t)blkaddr << LOG_SECTORS_PER_BLOCK;
-	bio->bi_private = bi_private;
-	return bio;
-}
-
 static inline void __submit_bio(struct bio *bio, unsigned int op,
 				unsigned int op_flags)
 {
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index f06a2fad7af2..21ade322cc81 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -1263,9 +1263,13 @@ static bool z_erofs_vle_submit_all(struct super_block *sb,
 		}
 
 		if (!bio) {
-			bio = erofs_grab_bio(sb, first_index + i,
-					     BIO_MAX_PAGES, bi_private,
-					     z_erofs_vle_read_endio, true);
+			bio = bio_alloc(GFP_NOIO, BIO_MAX_PAGES);
+
+			bio->bi_end_io = z_erofs_vle_read_endio;
+			bio_set_dev(bio, sb->s_bdev);
+			bio->bi_iter.bi_sector = (sector_t)(first_index + i) <<
+				LOG_SECTORS_PER_BLOCK;
+			bio->bi_private = bi_private;
 			++nr_bios;
 		}
 
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v2 16/25] erofs: kill prio and nofail of erofs_get_meta_page()
  2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
                       ` (14 preceding siblings ...)
  2019-09-04  2:09     ` [PATCH v2 15/25] erofs: localize erofs_grab_bio() Gao Xiang
@ 2019-09-04  2:09     ` Gao Xiang
  2019-09-04  2:09     ` [PATCH v2 17/25] erofs: kill __submit_bio() Gao Xiang
                       ` (10 subsequent siblings)
  26 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-04  2:09 UTC (permalink / raw)
  To: Chao Yu, Greg Kroah-Hartman, Christoph Hellwig, devel
  Cc: linux-fsdevel, linux-erofs, Chao Yu, Miao Xie, Gao Xiang

As Christoph pointed out [1],
"Why is there __erofs_get_meta_page with the two weird
booleans instead of a single erofs_get_meta_page that
gets and gfp_t for additional flags and an unsigned int
for additional bio op flags."

And since all callers can handle errors, let's kill
prio and nofail and erofs_get_inline_page() now.

[1] https://lore.kernel.org/r/20190830162812.GA10694@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/data.c     | 25 ++++++-------------------
 fs/erofs/inode.c    |  2 +-
 fs/erofs/internal.h | 18 +-----------------
 fs/erofs/xattr.c    | 13 ++++++-------
 fs/erofs/zmap.c     |  4 ++--
 5 files changed, 16 insertions(+), 46 deletions(-)

diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index 0136ea117934..28eda71bb1a9 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -51,25 +51,19 @@ static struct bio *erofs_grab_raw_bio(struct super_block *sb,
 	return bio;
 }
 
-/* prio -- true is used for dir */
-struct page *__erofs_get_meta_page(struct super_block *sb,
-				   erofs_blk_t blkaddr, bool prio, bool nofail)
+struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr)
 {
 	struct inode *const bd_inode = sb->s_bdev->bd_inode;
 	struct address_space *const mapping = bd_inode->i_mapping;
-	/* prefer retrying in the allocator to blindly looping below */
-	const gfp_t gfp = mapping_gfp_constraint(mapping, ~__GFP_FS) |
-		(nofail ? __GFP_NOFAIL : 0);
-	unsigned int io_retries = nofail ? EROFS_IO_MAX_RETRIES_NOFAIL : 0;
+	const gfp_t gfp = mapping_gfp_constraint(mapping, ~__GFP_FS);
 	struct page *page;
 	int err;
 
 repeat:
 	page = find_or_create_page(mapping, blkaddr, gfp);
-	if (!page) {
-		DBG_BUGON(nofail);
+	if (!page)
 		return ERR_PTR(-ENOMEM);
-	}
+
 	DBG_BUGON(!PageLocked(page));
 
 	if (!PageUptodate(page)) {
@@ -82,14 +76,11 @@ struct page *__erofs_get_meta_page(struct super_block *sb,
 			goto err_out;
 		}
 
-		__submit_bio(bio, REQ_OP_READ,
-			     REQ_META | (prio ? REQ_PRIO : 0));
-
+		__submit_bio(bio, REQ_OP_READ, REQ_META);
 		lock_page(page);
 
 		/* this page has been truncated by others */
 		if (page->mapping != mapping) {
-unlock_repeat:
 			unlock_page(page);
 			put_page(page);
 			goto repeat;
@@ -97,10 +88,6 @@ struct page *__erofs_get_meta_page(struct super_block *sb,
 
 		/* more likely a read error */
 		if (!PageUptodate(page)) {
-			if (io_retries) {
-				--io_retries;
-				goto unlock_repeat;
-			}
 			err = -EIO;
 			goto err_out;
 		}
@@ -251,7 +238,7 @@ static inline struct bio *erofs_read_raw_page(struct bio *bio,
 
 			DBG_BUGON(map.m_plen > PAGE_SIZE);
 
-			ipage = erofs_get_meta_page(inode->i_sb, blknr, 0);
+			ipage = erofs_get_meta_page(inode->i_sb, blknr);
 
 			if (IS_ERR(ipage)) {
 				err = PTR_ERR(ipage);
diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index 770f3259c862..8d496adbeaea 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -182,7 +182,7 @@ static int fill_inode(struct inode *inode, int isdir)
 	debugln("%s, reading inode nid %llu at %u of blkaddr %u",
 		__func__, vi->nid, ofs, blkaddr);
 
-	page = erofs_get_meta_page(inode->i_sb, blkaddr, isdir);
+	page = erofs_get_meta_page(inode->i_sb, blkaddr);
 
 	if (IS_ERR(page)) {
 		errln("failed to get inode (nid: %llu) page, err %ld",
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 000ea92b36a3..90c62fb5f80d 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -258,8 +258,6 @@ static inline int erofs_wait_on_workgroup_freezed(struct erofs_workgroup *grp)
 #error erofs cannot be used in this platform
 #endif
 
-#define EROFS_IO_MAX_RETRIES_NOFAIL     5
-
 #define ROOT_NID(sb)		((sb)->root_nid)
 
 #define erofs_blknr(addr)       ((addr) / EROFS_BLKSIZ)
@@ -418,24 +416,10 @@ static inline void __submit_bio(struct bio *bio, unsigned int op,
 	submit_bio(bio);
 }
 
-struct page *__erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr,
-				   bool prio, bool nofail);
-
-static inline struct page *erofs_get_meta_page(struct super_block *sb,
-	erofs_blk_t blkaddr, bool prio)
-{
-	return __erofs_get_meta_page(sb, blkaddr, prio, false);
-}
+struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr);
 
 int erofs_map_blocks(struct inode *, struct erofs_map_blocks *, int);
 
-static inline struct page *erofs_get_inline_page(struct inode *inode,
-						 erofs_blk_t blkaddr)
-{
-	return erofs_get_meta_page(inode->i_sb, blkaddr,
-				   S_ISDIR(inode->i_mode));
-}
-
 /* inode.c */
 static inline unsigned long erofs_inode_hash(erofs_nid_t nid)
 {
diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c
index d5b7fe0bee45..dd445c81c41f 100644
--- a/fs/erofs/xattr.c
+++ b/fs/erofs/xattr.c
@@ -87,7 +87,7 @@ static int init_inode_xattrs(struct inode *inode)
 	it.blkaddr = erofs_blknr(iloc(sbi, vi->nid) + vi->inode_isize);
 	it.ofs = erofs_blkoff(iloc(sbi, vi->nid) + vi->inode_isize);
 
-	it.page = erofs_get_inline_page(inode, it.blkaddr);
+	it.page = erofs_get_meta_page(sb, it.blkaddr);
 	if (IS_ERR(it.page)) {
 		ret = PTR_ERR(it.page);
 		goto out_unlock;
@@ -117,8 +117,7 @@ static int init_inode_xattrs(struct inode *inode)
 			DBG_BUGON(it.ofs != EROFS_BLKSIZ);
 			xattr_iter_end(&it, atomic_map);
 
-			it.page = erofs_get_meta_page(sb, ++it.blkaddr,
-						      S_ISDIR(inode->i_mode));
+			it.page = erofs_get_meta_page(sb, ++it.blkaddr);
 			if (IS_ERR(it.page)) {
 				kfree(vi->xattr_shared_xattrs);
 				vi->xattr_shared_xattrs = NULL;
@@ -168,7 +167,7 @@ static inline int xattr_iter_fixup(struct xattr_iter *it)
 
 	it->blkaddr += erofs_blknr(it->ofs);
 
-	it->page = erofs_get_meta_page(it->sb, it->blkaddr, false);
+	it->page = erofs_get_meta_page(it->sb, it->blkaddr);
 	if (IS_ERR(it->page)) {
 		int err = PTR_ERR(it->page);
 
@@ -199,7 +198,7 @@ static int inline_xattr_iter_begin(struct xattr_iter *it,
 	it->blkaddr = erofs_blknr(iloc(sbi, vi->nid) + inline_xattr_ofs);
 	it->ofs = erofs_blkoff(iloc(sbi, vi->nid) + inline_xattr_ofs);
 
-	it->page = erofs_get_inline_page(inode, it->blkaddr);
+	it->page = erofs_get_meta_page(inode->i_sb, it->blkaddr);
 	if (IS_ERR(it->page))
 		return PTR_ERR(it->page);
 
@@ -401,7 +400,7 @@ static int shared_getxattr(struct inode *inode, struct getxattr_iter *it)
 			if (i)
 				xattr_iter_end(&it->it, true);
 
-			it->it.page = erofs_get_meta_page(sb, blkaddr, false);
+			it->it.page = erofs_get_meta_page(sb, blkaddr);
 			if (IS_ERR(it->it.page))
 				return PTR_ERR(it->it.page);
 
@@ -623,7 +622,7 @@ static int shared_listxattr(struct listxattr_iter *it)
 			if (i)
 				xattr_iter_end(&it->it, true);
 
-			it->it.page = erofs_get_meta_page(sb, blkaddr, false);
+			it->it.page = erofs_get_meta_page(sb, blkaddr);
 			if (IS_ERR(it->it.page))
 				return PTR_ERR(it->it.page);
 
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index 30a5171637d7..9c141f145508 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -50,7 +50,7 @@ static int fill_inode_lazy(struct inode *inode)
 
 	pos = ALIGN(iloc(EROFS_SB(sb), vi->nid) + vi->inode_isize +
 		    vi->xattr_isize, 8);
-	page = erofs_get_meta_page(sb, erofs_blknr(pos), false);
+	page = erofs_get_meta_page(sb, erofs_blknr(pos));
 	if (IS_ERR(page)) {
 		err = PTR_ERR(page);
 		goto out_unlock;
@@ -127,7 +127,7 @@ static int z_erofs_reload_indexes(struct z_erofs_maprecorder *m,
 		put_page(mpage);
 	}
 
-	mpage = erofs_get_meta_page(sb, eblk, false);
+	mpage = erofs_get_meta_page(sb, eblk);
 	if (IS_ERR(mpage)) {
 		map->mpage = NULL;
 		return PTR_ERR(mpage);
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v2 17/25] erofs: kill __submit_bio()
  2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
                       ` (15 preceding siblings ...)
  2019-09-04  2:09     ` [PATCH v2 16/25] erofs: kill prio and nofail of erofs_get_meta_page() Gao Xiang
@ 2019-09-04  2:09     ` Gao Xiang
  2019-09-04  2:09     ` [PATCH v2 18/25] erofs: add "erofs_" prefix for common and short functions Gao Xiang
                       ` (9 subsequent siblings)
  26 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-04  2:09 UTC (permalink / raw)
  To: Chao Yu, Greg Kroah-Hartman, Christoph Hellwig, devel
  Cc: linux-fsdevel, linux-erofs, Chao Yu, Miao Xie, Gao Xiang

As Christoph pointed out [1], "
Why is there __submit_bio which really just obsfucates
what is going on?  Also why is __submit_bio using
bio_set_op_attrs instead of opencode it as the comment
right next to it asks you to? "

Let's use submit_bio directly instead.

[1] https://lore.kernel.org/r/20190830162812.GA10694@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/data.c     | 21 +++++++++++++--------
 fs/erofs/internal.h |  7 -------
 fs/erofs/zdata.c    |  6 ++++--
 3 files changed, 17 insertions(+), 17 deletions(-)

diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index 28eda71bb1a9..70b1e353756e 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -40,7 +40,8 @@ static inline void read_endio(struct bio *bio)
 
 static struct bio *erofs_grab_raw_bio(struct super_block *sb,
 				      erofs_blk_t blkaddr,
-				      unsigned int nr_pages)
+				      unsigned int nr_pages,
+				      bool ismeta)
 {
 	struct bio *bio = bio_alloc(GFP_NOIO, nr_pages);
 
@@ -48,6 +49,11 @@ static struct bio *erofs_grab_raw_bio(struct super_block *sb,
 	bio_set_dev(bio, sb->s_bdev);
 	bio->bi_iter.bi_sector = (sector_t)blkaddr << LOG_SECTORS_PER_BLOCK;
 	bio->bi_private = sb;
+	if (ismeta)
+		bio->bi_opf = REQ_OP_READ | REQ_META;
+	else
+		bio->bi_opf = REQ_OP_READ;
+
 	return bio;
 }
 
@@ -69,14 +75,14 @@ struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr)
 	if (!PageUptodate(page)) {
 		struct bio *bio;
 
-		bio = erofs_grab_raw_bio(sb, blkaddr, 1);
+		bio = erofs_grab_raw_bio(sb, blkaddr, 1, true);
 
 		if (bio_add_page(bio, page, PAGE_SIZE, 0) != PAGE_SIZE) {
 			err = -EFAULT;
 			goto err_out;
 		}
 
-		__submit_bio(bio, REQ_OP_READ, REQ_META);
+		submit_bio(bio);
 		lock_page(page);
 
 		/* this page has been truncated by others */
@@ -201,7 +207,7 @@ static inline struct bio *erofs_read_raw_page(struct bio *bio,
 	    /* not continuous */
 	    *last_block + 1 != current_block) {
 submit_bio_retry:
-		__submit_bio(bio, REQ_OP_READ, 0);
+		submit_bio(bio);
 		bio = NULL;
 	}
 
@@ -271,7 +277,7 @@ static inline struct bio *erofs_read_raw_page(struct bio *bio,
 		if (nblocks > BIO_MAX_PAGES)
 			nblocks = BIO_MAX_PAGES;
 
-		bio = erofs_grab_raw_bio(sb, blknr, nblocks);
+		bio = erofs_grab_raw_bio(sb, blknr, nblocks, false);
 	}
 
 	err = bio_add_page(bio, page, PAGE_SIZE, 0);
@@ -302,8 +308,7 @@ static inline struct bio *erofs_read_raw_page(struct bio *bio,
 	/* if updated manually, continuous pages has a gap */
 	if (bio)
 submit_bio_out:
-		__submit_bio(bio, REQ_OP_READ, 0);
-
+		submit_bio(bio);
 	return err ? ERR_PTR(err) : NULL;
 }
 
@@ -367,7 +372,7 @@ static int erofs_raw_access_readpages(struct file *filp,
 
 	/* the rare case (end in gaps) */
 	if (bio)
-		__submit_bio(bio, REQ_OP_READ, 0);
+		submit_bio(bio);
 	return 0;
 }
 
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 90c62fb5f80d..13c8d841c43a 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -409,13 +409,6 @@ static inline int z_erofs_map_blocks_iter(struct inode *inode,
 #endif	/* !CONFIG_EROFS_FS_ZIP */
 
 /* data.c */
-static inline void __submit_bio(struct bio *bio, unsigned int op,
-				unsigned int op_flags)
-{
-	bio_set_op_attrs(bio, op, op_flags);
-	submit_bio(bio);
-}
-
 struct page *erofs_get_meta_page(struct super_block *sb, erofs_blk_t blkaddr);
 
 int erofs_map_blocks(struct inode *, struct erofs_map_blocks *, int);
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index 21ade322cc81..3010fa3d1ac3 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -1258,7 +1258,7 @@ static bool z_erofs_vle_submit_all(struct super_block *sb,
 
 		if (bio && force_submit) {
 submit_bio_retry:
-			__submit_bio(bio, REQ_OP_READ, 0);
+			submit_bio(bio);
 			bio = NULL;
 		}
 
@@ -1270,6 +1270,8 @@ static bool z_erofs_vle_submit_all(struct super_block *sb,
 			bio->bi_iter.bi_sector = (sector_t)(first_index + i) <<
 				LOG_SECTORS_PER_BLOCK;
 			bio->bi_private = bi_private;
+			bio->bi_opf = REQ_OP_READ;
+
 			++nr_bios;
 		}
 
@@ -1290,7 +1292,7 @@ static bool z_erofs_vle_submit_all(struct super_block *sb,
 	} while (owned_head != Z_EROFS_PCLUSTER_TAIL);
 
 	if (bio)
-		__submit_bio(bio, REQ_OP_READ, 0);
+		submit_bio(bio);
 
 	if (postsubmit_is_all_bypassed(q, nr_bios, force_fg))
 		return true;
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v2 18/25] erofs: add "erofs_" prefix for common and short functions
  2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
                       ` (16 preceding siblings ...)
  2019-09-04  2:09     ` [PATCH v2 17/25] erofs: kill __submit_bio() Gao Xiang
@ 2019-09-04  2:09     ` Gao Xiang
  2019-09-04  2:09     ` [PATCH v2 19/25] erofs: kill all erofs specific fault injection Gao Xiang
                       ` (8 subsequent siblings)
  26 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-04  2:09 UTC (permalink / raw)
  To: Chao Yu, Greg Kroah-Hartman, Christoph Hellwig, devel
  Cc: linux-fsdevel, linux-erofs, Chao Yu, Miao Xie, Gao Xiang

Add erofs_ prefix to free_inode, alloc_inode, ...

Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/data.c         |  4 ++--
 fs/erofs/decompressor.c | 22 +++++++++++-----------
 fs/erofs/inode.c        |  8 ++++----
 fs/erofs/internal.h     |  2 +-
 fs/erofs/namei.c        | 12 ++++++------
 fs/erofs/super.c        | 40 ++++++++++++++++++++--------------------
 fs/erofs/zdata.c        | 19 ++++++++++---------
 7 files changed, 54 insertions(+), 53 deletions(-)

diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index 70b1e353756e..3ce87a88452a 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -9,7 +9,7 @@
 
 #include <trace/events/erofs.h>
 
-static inline void read_endio(struct bio *bio)
+static void erofs_readendio(struct bio *bio)
 {
 	struct super_block *const sb = bio->bi_private;
 	struct bio_vec *bvec;
@@ -45,7 +45,7 @@ static struct bio *erofs_grab_raw_bio(struct super_block *sb,
 {
 	struct bio *bio = bio_alloc(GFP_NOIO, nr_pages);
 
-	bio->bi_end_io = read_endio;
+	bio->bi_end_io = erofs_readendio;
 	bio_set_dev(bio, sb->s_bdev);
 	bio->bi_iter.bi_sector = (sector_t)blkaddr << LOG_SECTORS_PER_BLOCK;
 	bio->bi_private = sb;
diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index 555c04730f87..8ed38504a9f1 100644
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -32,8 +32,8 @@ static bool use_vmap;
 module_param(use_vmap, bool, 0444);
 MODULE_PARM_DESC(use_vmap, "Use vmap() instead of vm_map_ram() (default 0)");
 
-static int lz4_prepare_destpages(struct z_erofs_decompress_req *rq,
-				 struct list_head *pagepool)
+static int z_erofs_lz4_prepare_destpages(struct z_erofs_decompress_req *rq,
+					 struct list_head *pagepool)
 {
 	const unsigned int nr =
 		PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
@@ -114,7 +114,7 @@ static void *generic_copy_inplace_data(struct z_erofs_decompress_req *rq,
 	return tmp;
 }
 
-static int lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out)
+static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out)
 {
 	unsigned int inputmargin, inlen;
 	u8 *src;
@@ -188,8 +188,8 @@ static struct z_erofs_decompressor decompressors[] = {
 		.name = "shifted"
 	},
 	[Z_EROFS_COMPRESSION_LZ4] = {
-		.prepare_destpages = lz4_prepare_destpages,
-		.decompress = lz4_decompress,
+		.prepare_destpages = z_erofs_lz4_prepare_destpages,
+		.decompress = z_erofs_lz4_decompress,
 		.name = "lz4"
 	},
 };
@@ -247,8 +247,8 @@ static void erofs_vunmap(const void *mem, unsigned int count)
 		vunmap(mem);
 }
 
-static int decompress_generic(struct z_erofs_decompress_req *rq,
-			      struct list_head *pagepool)
+static int z_erofs_decompress_generic(struct z_erofs_decompress_req *rq,
+				      struct list_head *pagepool)
 {
 	const unsigned int nrpages_out =
 		PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
@@ -308,8 +308,8 @@ static int decompress_generic(struct z_erofs_decompress_req *rq,
 	return ret;
 }
 
-static int shifted_decompress(const struct z_erofs_decompress_req *rq,
-			      struct list_head *pagepool)
+static int z_erofs_shifted_transform(const struct z_erofs_decompress_req *rq,
+				     struct list_head *pagepool)
 {
 	const unsigned int nrpages_out =
 		PAGE_ALIGN(rq->pageofs_out + rq->outputsize) >> PAGE_SHIFT;
@@ -353,7 +353,7 @@ int z_erofs_decompress(struct z_erofs_decompress_req *rq,
 		       struct list_head *pagepool)
 {
 	if (rq->alg == Z_EROFS_COMPRESSION_SHIFTED)
-		return shifted_decompress(rq, pagepool);
-	return decompress_generic(rq, pagepool);
+		return z_erofs_shifted_transform(rq, pagepool);
+	return z_erofs_decompress_generic(rq, pagepool);
 }
 
diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index 8d496adbeaea..384905e0677c 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -9,7 +9,7 @@
 #include <trace/events/erofs.h>
 
 /* no locking */
-static int read_inode(struct inode *inode, void *data)
+static int erofs_read_inode(struct inode *inode, void *data)
 {
 	struct erofs_inode *vi = EROFS_I(inode);
 	struct erofs_inode_compact *dic = data;
@@ -163,7 +163,7 @@ static int erofs_fill_symlink(struct inode *inode, void *data,
 	return 0;
 }
 
-static int fill_inode(struct inode *inode, int isdir)
+static int erofs_fill_inode(struct inode *inode, int isdir)
 {
 	struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
 	struct erofs_inode *vi = EROFS_I(inode);
@@ -193,7 +193,7 @@ static int fill_inode(struct inode *inode, int isdir)
 	DBG_BUGON(!PageUptodate(page));
 	data = page_address(page);
 
-	err = read_inode(inode, data + ofs);
+	err = erofs_read_inode(inode, data + ofs);
 	if (!err) {
 		/* setup the new inode */
 		switch (inode->i_mode & S_IFMT) {
@@ -286,7 +286,7 @@ struct inode *erofs_iget(struct super_block *sb,
 
 		vi->nid = nid;
 
-		err = fill_inode(inode, isdir);
+		err = erofs_fill_inode(inode, isdir);
 		if (!err)
 			unlock_new_inode(inode);
 		else {
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 13c8d841c43a..881eb2ee18b5 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -308,7 +308,7 @@ struct erofs_inode {
 #define EROFS_I(ptr)	\
 	container_of(ptr, struct erofs_inode, vfs_inode)
 
-static inline unsigned long inode_datablocks(struct inode *inode)
+static inline unsigned long erofs_inode_datablocks(struct inode *inode)
 {
 	/* since i_size cannot be changed */
 	return DIV_ROUND_UP(inode->i_size, EROFS_BLKSIZ);
diff --git a/fs/erofs/namei.c b/fs/erofs/namei.c
index a6b6a4ab1403..6debc1d88282 100644
--- a/fs/erofs/namei.c
+++ b/fs/erofs/namei.c
@@ -14,9 +14,9 @@ struct erofs_qstr {
 };
 
 /* based on the end of qn is accurate and it must have the trailing '\0' */
-static inline int dirnamecmp(const struct erofs_qstr *qn,
-			     const struct erofs_qstr *qd,
-			     unsigned int *matched)
+static inline int erofs_dirnamecmp(const struct erofs_qstr *qn,
+				   const struct erofs_qstr *qd,
+				   unsigned int *matched)
 {
 	unsigned int i = *matched;
 
@@ -71,7 +71,7 @@ static struct erofs_dirent *find_target_dirent(struct erofs_qstr *name,
 		};
 
 		/* string comparison without already matched prefix */
-		int ret = dirnamecmp(name, &dname, &matched);
+		int ret = erofs_dirnamecmp(name, &dname, &matched);
 
 		if (!ret) {
 			return de + mid;
@@ -98,7 +98,7 @@ static struct page *find_target_block_classic(struct inode *dir,
 
 	startprfx = endprfx = 0;
 	head = 0;
-	back = inode_datablocks(dir) - 1;
+	back = erofs_inode_datablocks(dir) - 1;
 
 	while (head <= back) {
 		const int mid = head + (back - head) / 2;
@@ -134,7 +134,7 @@ static struct page *find_target_block_classic(struct inode *dir,
 							  EROFS_BLKSIZ);
 
 			/* string comparison without already matched prefix */
-			diff = dirnamecmp(name, &dname, &matched);
+			diff = erofs_dirnamecmp(name, &dname, &matched);
 			kunmap_atomic(de);
 
 			if (!diff) {
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index b64d69f18270..36e569a79172 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -16,14 +16,14 @@
 
 static struct kmem_cache *erofs_inode_cachep __read_mostly;
 
-static void init_once(void *ptr)
+static void erofs_inode_init_once(void *ptr)
 {
 	struct erofs_inode *vi = ptr;
 
 	inode_init_once(&vi->vfs_inode);
 }
 
-static struct inode *alloc_inode(struct super_block *sb)
+static struct inode *erofs_alloc_inode(struct super_block *sb)
 {
 	struct erofs_inode *vi =
 		kmem_cache_alloc(erofs_inode_cachep, GFP_KERNEL);
@@ -36,7 +36,7 @@ static struct inode *alloc_inode(struct super_block *sb)
 	return &vi->vfs_inode;
 }
 
-static void free_inode(struct inode *inode)
+static void erofs_free_inode(struct inode *inode)
 {
 	struct erofs_inode *vi = EROFS_I(inode);
 
@@ -64,7 +64,7 @@ static bool check_layout_compatibility(struct super_block *sb,
 	return true;
 }
 
-static int superblock_read(struct super_block *sb)
+static int erofs_read_superblock(struct super_block *sb)
 {
 	struct erofs_sb_info *sbi;
 	struct buffer_head *bh;
@@ -218,7 +218,7 @@ static int erofs_build_cache_strategy(struct erofs_sb_info *sbi,
 #endif
 
 /* set up default EROFS parameters */
-static void default_options(struct erofs_sb_info *sbi)
+static void erofs_default_options(struct erofs_sb_info *sbi)
 {
 #ifdef CONFIG_EROFS_FS_ZIP
 	sbi->cache_strategy = EROFS_ZIP_CACHE_READAROUND;
@@ -252,7 +252,7 @@ static match_table_t erofs_tokens = {
 	{Opt_err, NULL}
 };
 
-static int parse_options(struct super_block *sb, char *options)
+static int erofs_parse_options(struct super_block *sb, char *options)
 {
 	substring_t args[MAX_OPT_ARGS];
 	char *p;
@@ -322,7 +322,7 @@ static int parse_options(struct super_block *sb, char *options)
 #ifdef CONFIG_EROFS_FS_ZIP
 static const struct address_space_operations managed_cache_aops;
 
-static int managed_cache_releasepage(struct page *page, gfp_t gfp_mask)
+static int erofs_managed_cache_releasepage(struct page *page, gfp_t gfp_mask)
 {
 	int ret = 1;	/* 0 - busy */
 	struct address_space *const mapping = page->mapping;
@@ -336,9 +336,9 @@ static int managed_cache_releasepage(struct page *page, gfp_t gfp_mask)
 	return ret;
 }
 
-static void managed_cache_invalidatepage(struct page *page,
-					 unsigned int offset,
-					 unsigned int length)
+static void erofs_managed_cache_invalidatepage(struct page *page,
+					       unsigned int offset,
+					       unsigned int length)
 {
 	const unsigned int stop = length + offset;
 
@@ -348,13 +348,13 @@ static void managed_cache_invalidatepage(struct page *page,
 	DBG_BUGON(stop > PAGE_SIZE || stop < length);
 
 	if (offset == 0 && stop == PAGE_SIZE)
-		while (!managed_cache_releasepage(page, GFP_NOFS))
+		while (!erofs_managed_cache_releasepage(page, GFP_NOFS))
 			cond_resched();
 }
 
 static const struct address_space_operations managed_cache_aops = {
-	.releasepage = managed_cache_releasepage,
-	.invalidatepage = managed_cache_invalidatepage,
+	.releasepage = erofs_managed_cache_releasepage,
+	.invalidatepage = erofs_managed_cache_invalidatepage,
 };
 
 static int erofs_init_managed_cache(struct super_block *sb)
@@ -396,7 +396,7 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
 		return -ENOMEM;
 
 	sb->s_fs_info = sbi;
-	err = superblock_read(sb);
+	err = erofs_read_superblock(sb);
 	if (err)
 		return err;
 
@@ -410,9 +410,9 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
 	sb->s_xattr = erofs_xattr_handlers;
 #endif
 	/* set erofs default mount options */
-	default_options(sbi);
+	erofs_default_options(sbi);
 
-	err = parse_options(sb, data);
+	err = erofs_parse_options(sb, data);
 	if (err)
 		return err;
 
@@ -512,7 +512,7 @@ static int __init erofs_module_init(void)
 	erofs_inode_cachep = kmem_cache_create("erofs_inode",
 					       sizeof(struct erofs_inode), 0,
 					       SLAB_RECLAIM_ACCOUNT,
-					       init_once);
+					       erofs_inode_init_once);
 	if (!erofs_inode_cachep) {
 		err = -ENOMEM;
 		goto icache_err;
@@ -619,7 +619,7 @@ static int erofs_remount(struct super_block *sb, int *flags, char *data)
 	int err;
 
 	DBG_BUGON(!sb_rdonly(sb));
-	err = parse_options(sb, data);
+	err = erofs_parse_options(sb, data);
 	if (err)
 		goto out;
 
@@ -639,8 +639,8 @@ static int erofs_remount(struct super_block *sb, int *flags, char *data)
 
 const struct super_operations erofs_sops = {
 	.put_super = erofs_put_super,
-	.alloc_inode = alloc_inode,
-	.free_inode = free_inode,
+	.alloc_inode = erofs_alloc_inode,
+	.free_inode = erofs_free_inode,
 	.statfs = erofs_statfs,
 	.show_options = erofs_show_options,
 	.remount_fs = erofs_remount,
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index 3010fa3d1ac3..8587d6751c48 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -40,7 +40,7 @@ void z_erofs_exit_zip_subsystem(void)
 	kmem_cache_destroy(pcluster_cachep);
 }
 
-static inline int init_unzip_workqueue(void)
+static inline int z_erofs_init_workqueue(void)
 {
 	const unsigned int onlinecpus = num_possible_cpus();
 	const unsigned int flags = WQ_UNBOUND | WQ_HIGHPRI | WQ_CPU_INTENSIVE;
@@ -54,7 +54,7 @@ static inline int init_unzip_workqueue(void)
 	return z_erofs_workqueue ? 0 : -ENOMEM;
 }
 
-static void init_once(void *ptr)
+static void z_erofs_pcluster_init_once(void *ptr)
 {
 	struct z_erofs_pcluster *pcl = ptr;
 	struct z_erofs_collection *cl = z_erofs_primarycollection(pcl);
@@ -67,7 +67,7 @@ static void init_once(void *ptr)
 		pcl->compressed_pages[i] = NULL;
 }
 
-static void init_always(struct z_erofs_pcluster *pcl)
+static void z_erofs_pcluster_init_always(struct z_erofs_pcluster *pcl)
 {
 	struct z_erofs_collection *cl = z_erofs_primarycollection(pcl);
 
@@ -81,9 +81,10 @@ int __init z_erofs_init_zip_subsystem(void)
 {
 	pcluster_cachep = kmem_cache_create("erofs_compress",
 					    Z_EROFS_WORKGROUP_SIZE, 0,
-					    SLAB_RECLAIM_ACCOUNT, init_once);
+					    SLAB_RECLAIM_ACCOUNT,
+					    z_erofs_pcluster_init_once);
 	if (pcluster_cachep) {
-		if (!init_unzip_workqueue())
+		if (!z_erofs_init_workqueue())
 			return 0;
 
 		kmem_cache_destroy(pcluster_cachep);
@@ -272,8 +273,8 @@ int erofs_try_to_free_cached_page(struct address_space *mapping,
 }
 
 /* page_type must be Z_EROFS_PAGE_TYPE_EXCLUSIVE */
-static inline bool try_inplace_io(struct z_erofs_collector *clt,
-				  struct page *page)
+static inline bool z_erofs_try_inplace_io(struct z_erofs_collector *clt,
+					  struct page *page)
 {
 	struct z_erofs_pcluster *const pcl = clt->pcl;
 	const unsigned int clusterpages = BIT(pcl->clusterbits);
@@ -296,7 +297,7 @@ static int z_erofs_attach_page(struct z_erofs_collector *clt,
 	/* give priority for inplaceio */
 	if (clt->mode >= COLLECT_PRIMARY &&
 	    type == Z_EROFS_PAGE_TYPE_EXCLUSIVE &&
-	    try_inplace_io(clt, page))
+	    z_erofs_try_inplace_io(clt, page))
 		return 0;
 
 	ret = z_erofs_pagevec_enqueue(&clt->vector,
@@ -409,7 +410,7 @@ static struct z_erofs_collection *clregister(struct z_erofs_collector *clt,
 	if (!pcl)
 		return ERR_PTR(-ENOMEM);
 
-	init_always(pcl);
+	z_erofs_pcluster_init_always(pcl);
 	pcl->obj.index = map->m_pa >> PAGE_SHIFT;
 
 	pcl->length = (map->m_llen << Z_EROFS_PCLUSTER_LENGTH_BIT) |
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v2 19/25] erofs: kill all erofs specific fault injection
  2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
                       ` (17 preceding siblings ...)
  2019-09-04  2:09     ` [PATCH v2 18/25] erofs: add "erofs_" prefix for common and short functions Gao Xiang
@ 2019-09-04  2:09     ` Gao Xiang
  2019-09-04  2:09     ` [PATCH v2 20/25] erofs: kill use_vmap module parameter Gao Xiang
                       ` (7 subsequent siblings)
  26 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-04  2:09 UTC (permalink / raw)
  To: Chao Yu, Greg Kroah-Hartman, Christoph Hellwig, devel
  Cc: linux-fsdevel, linux-erofs, Chao Yu, Miao Xie, Gao Xiang

As Christoph suggested [1], "Please just use plain kmalloc
everywhere and let the normal kernel error injection code
take care of injeting any errors."

[1] https://lore.kernel.org/r/20190829102426.GE20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 Documentation/filesystems/erofs.txt |  5 ---
 fs/erofs/Kconfig                    |  7 ---
 fs/erofs/data.c                     |  7 ---
 fs/erofs/inode.c                    |  3 +-
 fs/erofs/internal.h                 | 65 ---------------------------
 fs/erofs/super.c                    | 70 -----------------------------
 fs/erofs/zdata.c                    |  8 +---
 7 files changed, 2 insertions(+), 163 deletions(-)

diff --git a/Documentation/filesystems/erofs.txt b/Documentation/filesystems/erofs.txt
index 38aa9126ec98..c3b5f603b2b6 100644
--- a/Documentation/filesystems/erofs.txt
+++ b/Documentation/filesystems/erofs.txt
@@ -52,11 +52,6 @@ linux-erofs mailing list:
 Mount options
 =============
 
-fault_injection=%d     Enable fault injection in all supported types with
-                       specified injection rate. Supported injection type:
-                       Type_Name                Type_Value
-                       FAULT_KMALLOC            0x000000001
-                       FAULT_READ_IO            0x000000002
 (no)user_xattr         Setup Extended User Attributes. Note: xattr is enabled
                        by default if CONFIG_EROFS_FS_XATTR is selected.
 (no)acl                Setup POSIX Access Control List. Note: acl is enabled
diff --git a/fs/erofs/Kconfig b/fs/erofs/Kconfig
index 16316d1adca3..9d634d3a1845 100644
--- a/fs/erofs/Kconfig
+++ b/fs/erofs/Kconfig
@@ -27,13 +27,6 @@ config EROFS_FS_DEBUG
 
 	  For daily use, say N.
 
-config EROFS_FAULT_INJECTION
-	bool "EROFS fault injection facility"
-	depends on EROFS_FS
-	help
-	  Test EROFS to inject faults such as ENOMEM, EIO, and so on.
-	  If unsure, say N.
-
 config EROFS_FS_XATTR
 	bool "EROFS extended attributes"
 	depends on EROFS_FS
diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index 3ce87a88452a..b5f5b8592d14 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -11,16 +11,10 @@
 
 static void erofs_readendio(struct bio *bio)
 {
-	struct super_block *const sb = bio->bi_private;
 	struct bio_vec *bvec;
 	blk_status_t err = bio->bi_status;
 	struct bvec_iter_all iter_all;
 
-	if (time_to_inject(EROFS_SB(sb), FAULT_READ_IO)) {
-		erofs_show_injection_info(FAULT_READ_IO);
-		err = BLK_STS_IOERR;
-	}
-
 	bio_for_each_segment_all(bvec, bio, iter_all) {
 		struct page *page = bvec->bv_page;
 
@@ -48,7 +42,6 @@ static struct bio *erofs_grab_raw_bio(struct super_block *sb,
 	bio->bi_end_io = erofs_readendio;
 	bio_set_dev(bio, sb->s_bdev);
 	bio->bi_iter.bi_sector = (sector_t)blkaddr << LOG_SECTORS_PER_BLOCK;
-	bio->bi_private = sb;
 	if (ismeta)
 		bio->bi_opf = REQ_OP_READ | REQ_META;
 	else
diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index 384905e0677c..8e53765a532c 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -131,7 +131,6 @@ static int erofs_fill_symlink(struct inode *inode, void *data,
 			      unsigned int m_pofs)
 {
 	struct erofs_inode *vi = EROFS_I(inode);
-	struct erofs_sb_info *sbi = EROFS_I_SB(inode);
 	char *lnk;
 
 	/* if it cannot be handled with fast symlink scheme */
@@ -141,7 +140,7 @@ static int erofs_fill_symlink(struct inode *inode, void *data,
 		return 0;
 	}
 
-	lnk = erofs_kmalloc(sbi, inode->i_size + 1, GFP_KERNEL);
+	lnk = kmalloc(inode->i_size + 1, GFP_KERNEL);
 	if (!lnk)
 		return -ENOMEM;
 
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 881eb2ee18b5..d659c1941f93 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -32,23 +32,6 @@
 #define DBG_BUGON(x)            ((void)(x))
 #endif	/* !CONFIG_EROFS_FS_DEBUG */
 
-enum {
-	FAULT_KMALLOC,
-	FAULT_READ_IO,
-	FAULT_MAX,
-};
-
-#ifdef CONFIG_EROFS_FAULT_INJECTION
-extern const char *erofs_fault_name[FAULT_MAX];
-#define IS_FAULT_SET(fi, type) ((fi)->inject_type & (1 << (type)))
-
-struct erofs_fault_info {
-	atomic_t inject_ops;
-	unsigned int inject_rate;
-	unsigned int inject_type;
-};
-#endif	/* CONFIG_EROFS_FAULT_INJECTION */
-
 /* EROFS_SUPER_MAGIC_V1 to represent the whole file system */
 #define EROFS_SUPER_MAGIC   EROFS_SUPER_MAGIC_V1
 
@@ -99,62 +82,14 @@ struct erofs_sb_info {
 	u32 feature_incompat;
 
 	unsigned int mount_opt;
-
-#ifdef CONFIG_EROFS_FAULT_INJECTION
-	struct erofs_fault_info fault_info;	/* For fault injection */
-#endif
 };
 
-#ifdef CONFIG_EROFS_FAULT_INJECTION
-#define erofs_show_injection_info(type)					\
-	infoln("inject %s in %s of %pS", erofs_fault_name[type],        \
-		__func__, __builtin_return_address(0))
-
-static inline bool time_to_inject(struct erofs_sb_info *sbi, int type)
-{
-	struct erofs_fault_info *ffi = &sbi->fault_info;
-
-	if (!ffi->inject_rate)
-		return false;
-
-	if (!IS_FAULT_SET(ffi, type))
-		return false;
-
-	atomic_inc(&ffi->inject_ops);
-	if (atomic_read(&ffi->inject_ops) >= ffi->inject_rate) {
-		atomic_set(&ffi->inject_ops, 0);
-		return true;
-	}
-	return false;
-}
-#else
-static inline bool time_to_inject(struct erofs_sb_info *sbi, int type)
-{
-	return false;
-}
-
-static inline void erofs_show_injection_info(int type)
-{
-}
-#endif	/* !CONFIG_EROFS_FAULT_INJECTION */
-
-static inline void *erofs_kmalloc(struct erofs_sb_info *sbi,
-					size_t size, gfp_t flags)
-{
-	if (time_to_inject(sbi, FAULT_KMALLOC)) {
-		erofs_show_injection_info(FAULT_KMALLOC);
-		return NULL;
-	}
-	return kmalloc(size, flags);
-}
-
 #define EROFS_SB(sb) ((struct erofs_sb_info *)(sb)->s_fs_info)
 #define EROFS_I_SB(inode) ((struct erofs_sb_info *)(inode)->i_sb->s_fs_info)
 
 /* Mount flags set via mount options or defaults */
 #define EROFS_MOUNT_XATTR_USER		0x00000010
 #define EROFS_MOUNT_POSIX_ACL		0x00000020
-#define EROFS_MOUNT_FAULT_INJECTION	0x00000040
 
 #define clear_opt(sbi, option)	((sbi)->mount_opt &= ~EROFS_MOUNT_##option)
 #define set_opt(sbi, option)	((sbi)->mount_opt |= EROFS_MOUNT_##option)
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 36e569a79172..407c95854be1 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -126,63 +126,6 @@ static int erofs_read_superblock(struct super_block *sb)
 	return ret;
 }
 
-#ifdef CONFIG_EROFS_FAULT_INJECTION
-const char *erofs_fault_name[FAULT_MAX] = {
-	[FAULT_KMALLOC]		= "kmalloc",
-	[FAULT_READ_IO]		= "read IO error",
-};
-
-static void __erofs_build_fault_attr(struct erofs_sb_info *sbi,
-				     unsigned int rate)
-{
-	struct erofs_fault_info *ffi = &sbi->fault_info;
-
-	if (rate) {
-		atomic_set(&ffi->inject_ops, 0);
-		ffi->inject_rate = rate;
-		ffi->inject_type = (1 << FAULT_MAX) - 1;
-	} else {
-		memset(ffi, 0, sizeof(struct erofs_fault_info));
-	}
-
-	set_opt(sbi, FAULT_INJECTION);
-}
-
-static int erofs_build_fault_attr(struct erofs_sb_info *sbi,
-				  substring_t *args)
-{
-	int rate = 0;
-
-	if (args->from && match_int(args, &rate))
-		return -EINVAL;
-
-	__erofs_build_fault_attr(sbi, rate);
-	return 0;
-}
-
-static unsigned int erofs_get_fault_rate(struct erofs_sb_info *sbi)
-{
-	return sbi->fault_info.inject_rate;
-}
-#else
-static void __erofs_build_fault_attr(struct erofs_sb_info *sbi,
-				     unsigned int rate)
-{
-}
-
-static int erofs_build_fault_attr(struct erofs_sb_info *sbi,
-				  substring_t *args)
-{
-	infoln("fault_injection options not supported");
-	return 0;
-}
-
-static unsigned int erofs_get_fault_rate(struct erofs_sb_info *sbi)
-{
-	return 0;
-}
-#endif
-
 #ifdef CONFIG_EROFS_FS_ZIP
 static int erofs_build_cache_strategy(struct erofs_sb_info *sbi,
 				      substring_t *args)
@@ -237,7 +180,6 @@ enum {
 	Opt_nouser_xattr,
 	Opt_acl,
 	Opt_noacl,
-	Opt_fault_injection,
 	Opt_cache_strategy,
 	Opt_err
 };
@@ -247,7 +189,6 @@ static match_table_t erofs_tokens = {
 	{Opt_nouser_xattr, "nouser_xattr"},
 	{Opt_acl, "acl"},
 	{Opt_noacl, "noacl"},
-	{Opt_fault_injection, "fault_injection=%u"},
 	{Opt_cache_strategy, "cache_strategy=%s"},
 	{Opt_err, NULL}
 };
@@ -301,11 +242,6 @@ static int erofs_parse_options(struct super_block *sb, char *options)
 			infoln("noacl options not supported");
 			break;
 #endif
-		case Opt_fault_injection:
-			err = erofs_build_fault_attr(EROFS_SB(sb), args);
-			if (err)
-				return err;
-			break;
 		case Opt_cache_strategy:
 			err = erofs_build_cache_strategy(EROFS_SB(sb), args);
 			if (err)
@@ -593,9 +529,6 @@ static int erofs_show_options(struct seq_file *seq, struct dentry *root)
 	else
 		seq_puts(seq, ",noacl");
 #endif
-	if (test_opt(sbi, FAULT_INJECTION))
-		seq_printf(seq, ",fault_injection=%u",
-			   erofs_get_fault_rate(sbi));
 #ifdef CONFIG_EROFS_FS_ZIP
 	if (sbi->cache_strategy == EROFS_ZIP_CACHE_DISABLED) {
 		seq_puts(seq, ",cache_strategy=disabled");
@@ -615,7 +548,6 @@ static int erofs_remount(struct super_block *sb, int *flags, char *data)
 {
 	struct erofs_sb_info *sbi = EROFS_SB(sb);
 	unsigned int org_mnt_opt = sbi->mount_opt;
-	unsigned int org_inject_rate = erofs_get_fault_rate(sbi);
 	int err;
 
 	DBG_BUGON(!sb_rdonly(sb));
@@ -631,9 +563,7 @@ static int erofs_remount(struct super_block *sb, int *flags, char *data)
 	*flags |= SB_RDONLY;
 	return 0;
 out:
-	__erofs_build_fault_attr(sbi, org_inject_rate);
 	sbi->mount_opt = org_mnt_opt;
-
 	return err;
 }
 
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index 8587d6751c48..ff8ab444172d 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -724,15 +724,9 @@ static inline void z_erofs_vle_read_endio(struct bio *bio)
 		DBG_BUGON(PageUptodate(page));
 		DBG_BUGON(!page->mapping);
 
-		if (!sbi && !z_erofs_page_is_staging(page)) {
+		if (!sbi && !z_erofs_page_is_staging(page))
 			sbi = EROFS_SB(page->mapping->host->i_sb);
 
-			if (time_to_inject(sbi, FAULT_READ_IO)) {
-				erofs_show_injection_info(FAULT_READ_IO);
-				err = BLK_STS_IOERR;
-			}
-		}
-
 		/* sbi should already be gotten if the page is managed */
 		if (sbi)
 			cachemngd = erofs_page_is_managed(sbi, page);
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v2 20/25] erofs: kill use_vmap module parameter
  2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
                       ` (18 preceding siblings ...)
  2019-09-04  2:09     ` [PATCH v2 19/25] erofs: kill all erofs specific fault injection Gao Xiang
@ 2019-09-04  2:09     ` Gao Xiang
  2019-09-04  2:09     ` [PATCH v2 21/25] erofs: save one level of indentation Gao Xiang
                       ` (6 subsequent siblings)
  26 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-04  2:09 UTC (permalink / raw)
  To: Chao Yu, Greg Kroah-Hartman, Christoph Hellwig, devel
  Cc: linux-fsdevel, linux-erofs, Chao Yu, Miao Xie, Gao Xiang

As Christoph said [1],
"vm_map_ram is supposed to generally behave better.  So if
it doesn't please report that that to the arch maintainer
and linux-mm so that they can look into the issue.  Having
user make choices of deep down kernel internals is just
a horrible interface.

Please talk to maintainers of other bits of the kernel
if you see issues and / or need enhancements. "

Let's redo the previous conclusion and kill the vmap
approach.

[1] https://lore.kernel.org/r/20190830165533.GA10909@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 Documentation/filesystems/erofs.txt |  4 ---
 fs/erofs/decompressor.c             | 46 ++++++++---------------------
 2 files changed, 13 insertions(+), 37 deletions(-)

diff --git a/Documentation/filesystems/erofs.txt b/Documentation/filesystems/erofs.txt
index c3b5f603b2b6..b0c085326e2e 100644
--- a/Documentation/filesystems/erofs.txt
+++ b/Documentation/filesystems/erofs.txt
@@ -67,10 +67,6 @@ cache_strategy=%s      Select a strategy for cached decompression from now on:
                                    It still does in-place I/O decompression
                                    for the rest compressed physical clusters.
 
-Module parameters
-=================
-use_vmap=[0|1]         Use vmap() instead of vm_map_ram() (default 0).
-
 On-disk details
 ===============
 
diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index 8ed38504a9f1..37177d49d125 100644
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -28,10 +28,6 @@ struct z_erofs_decompressor {
 	char *name;
 };
 
-static bool use_vmap;
-module_param(use_vmap, bool, 0444);
-MODULE_PARM_DESC(use_vmap, "Use vmap() instead of vm_map_ram() (default 0)");
-
 static int z_erofs_lz4_prepare_destpages(struct z_erofs_decompress_req *rq,
 					 struct list_head *pagepool)
 {
@@ -221,32 +217,6 @@ static void copy_from_pcpubuf(struct page **out, const char *dst,
 	}
 }
 
-static void *erofs_vmap(struct page **pages, unsigned int count)
-{
-	int i = 0;
-
-	if (use_vmap)
-		return vmap(pages, count, VM_MAP, PAGE_KERNEL);
-
-	while (1) {
-		void *addr = vm_map_ram(pages, count, -1, PAGE_KERNEL);
-
-		/* retry two more times (totally 3 times) */
-		if (addr || ++i >= 3)
-			return addr;
-		vm_unmap_aliases();
-	}
-	return NULL;
-}
-
-static void erofs_vunmap(const void *mem, unsigned int count)
-{
-	if (!use_vmap)
-		vm_unmap_ram(mem, count);
-	else
-		vunmap(mem);
-}
-
 static int z_erofs_decompress_generic(struct z_erofs_decompress_req *rq,
 				      struct list_head *pagepool)
 {
@@ -255,7 +225,7 @@ static int z_erofs_decompress_generic(struct z_erofs_decompress_req *rq,
 	const struct z_erofs_decompressor *alg = decompressors + rq->alg;
 	unsigned int dst_maptype;
 	void *dst;
-	int ret;
+	int ret, i;
 
 	if (nrpages_out == 1 && !rq->inplace_io) {
 		DBG_BUGON(!*rq->out);
@@ -293,9 +263,19 @@ static int z_erofs_decompress_generic(struct z_erofs_decompress_req *rq,
 		goto dstmap_out;
 	}
 
-	dst = erofs_vmap(rq->out, nrpages_out);
+	i = 0;
+	while (1) {
+		dst = vm_map_ram(rq->out, nrpages_out, -1, PAGE_KERNEL);
+
+		/* retry two more times (totally 3 times) */
+		if (dst || ++i >= 3)
+			break;
+		vm_unmap_aliases();
+	}
+
 	if (!dst)
 		return -ENOMEM;
+
 	dst_maptype = 2;
 
 dstmap_out:
@@ -304,7 +284,7 @@ static int z_erofs_decompress_generic(struct z_erofs_decompress_req *rq,
 	if (!dst_maptype)
 		kunmap_atomic(dst);
 	else if (dst_maptype == 2)
-		erofs_vunmap(dst, nrpages_out);
+		vm_unmap_ram(dst, nrpages_out);
 	return ret;
 }
 
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v2 21/25] erofs: save one level of indentation
  2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
                       ` (19 preceding siblings ...)
  2019-09-04  2:09     ` [PATCH v2 20/25] erofs: kill use_vmap module parameter Gao Xiang
@ 2019-09-04  2:09     ` Gao Xiang
  2019-09-04  2:09     ` [PATCH v2 22/25] erofs: rename errln/infoln/debugln to erofs_{err,info,dbg} Gao Xiang
                       ` (5 subsequent siblings)
  26 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-04  2:09 UTC (permalink / raw)
  To: Chao Yu, Greg Kroah-Hartman, Christoph Hellwig, devel
  Cc: linux-fsdevel, linux-erofs, Chao Yu, Miao Xie, Gao Xiang

As Christoph said [1], ".. and save one
level of indentation."

[1] https://lore.kernel.org/r/20190829102426.GE20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/inode.c | 65 ++++++++++++++++++++++++------------------------
 1 file changed, 33 insertions(+), 32 deletions(-)

diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index 8e53765a532c..5a6d3282fefb 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -193,41 +193,42 @@ static int erofs_fill_inode(struct inode *inode, int isdir)
 	data = page_address(page);
 
 	err = erofs_read_inode(inode, data + ofs);
-	if (!err) {
-		/* setup the new inode */
-		switch (inode->i_mode & S_IFMT) {
-		case S_IFREG:
-			inode->i_op = &erofs_generic_iops;
-			inode->i_fop = &generic_ro_fops;
-			break;
-		case S_IFDIR:
-			inode->i_op = &erofs_dir_iops;
-			inode->i_fop = &erofs_dir_fops;
-			break;
-		case S_IFLNK:
-			err = erofs_fill_symlink(inode, data, ofs);
-			if (err)
-				goto out_unlock;
-			inode_nohighmem(inode);
-			break;
-		case S_IFCHR:
-		case S_IFBLK:
-		case S_IFIFO:
-		case S_IFSOCK:
-			inode->i_op = &erofs_generic_iops;
-			init_special_inode(inode, inode->i_mode, inode->i_rdev);
-			goto out_unlock;
-		default:
-			err = -EFSCORRUPTED;
+	if (err)
+		goto out_unlock;
+
+	/* setup the new inode */
+	switch (inode->i_mode & S_IFMT) {
+	case S_IFREG:
+		inode->i_op = &erofs_generic_iops;
+		inode->i_fop = &generic_ro_fops;
+		break;
+	case S_IFDIR:
+		inode->i_op = &erofs_dir_iops;
+		inode->i_fop = &erofs_dir_fops;
+		break;
+	case S_IFLNK:
+		err = erofs_fill_symlink(inode, data, ofs);
+		if (err)
 			goto out_unlock;
-		}
+		inode_nohighmem(inode);
+		break;
+	case S_IFCHR:
+	case S_IFBLK:
+	case S_IFIFO:
+	case S_IFSOCK:
+		inode->i_op = &erofs_generic_iops;
+		init_special_inode(inode, inode->i_mode, inode->i_rdev);
+		goto out_unlock;
+	default:
+		err = -EFSCORRUPTED;
+		goto out_unlock;
+	}
 
-		if (erofs_inode_is_data_compressed(vi->datalayout)) {
-			err = z_erofs_fill_inode(inode);
-			goto out_unlock;
-		}
-		inode->i_mapping->a_ops = &erofs_raw_access_aops;
+	if (erofs_inode_is_data_compressed(vi->datalayout)) {
+		err = z_erofs_fill_inode(inode);
+		goto out_unlock;
 	}
+	inode->i_mapping->a_ops = &erofs_raw_access_aops;
 
 out_unlock:
 	unlock_page(page);
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v2 22/25] erofs: rename errln/infoln/debugln to erofs_{err,info,dbg}
  2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
                       ` (20 preceding siblings ...)
  2019-09-04  2:09     ` [PATCH v2 21/25] erofs: save one level of indentation Gao Xiang
@ 2019-09-04  2:09     ` Gao Xiang
  2019-09-04  2:09     ` [PATCH v2 23/25] erofs: use read_mapping_page instead of sb_bread Gao Xiang
                       ` (4 subsequent siblings)
  26 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-04  2:09 UTC (permalink / raw)
  To: Chao Yu, Greg Kroah-Hartman, Christoph Hellwig, devel
  Cc: linux-fsdevel, linux-erofs, Chao Yu, Miao Xie, Gao Xiang

Add prefix "erofs_" to these functions and print
sb->s_id as a prefix to erofs_{err, info} so that
the user knows which file system is affected.

Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/data.c         | 10 +++--
 fs/erofs/decompressor.c |  5 +--
 fs/erofs/dir.c          | 17 +++++----
 fs/erofs/inode.c        | 31 ++++++++-------
 fs/erofs/internal.h     | 14 +++++--
 fs/erofs/namei.c        |  9 +++--
 fs/erofs/super.c        | 83 +++++++++++++++++++++++++++--------------
 fs/erofs/xattr.c        |  8 ++--
 fs/erofs/zdata.c        | 13 ++++---
 fs/erofs/zdata.h        |  2 +-
 fs/erofs/zmap.c         | 37 ++++++++++--------
 11 files changed, 139 insertions(+), 90 deletions(-)

diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index b5f5b8592d14..eb7bbae89ed0 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -137,8 +137,9 @@ static int erofs_map_blocks_flatmode(struct inode *inode,
 
 		/* inline data should be located in one meta block */
 		if (erofs_blkoff(map->m_pa) + map->m_plen > PAGE_SIZE) {
-			errln("inline data cross block boundary @ nid %llu",
-			      vi->nid);
+			erofs_err(inode->i_sb,
+				  "inline data cross block boundary @ nid %llu",
+				  vi->nid);
 			DBG_BUGON(1);
 			err = -EFSCORRUPTED;
 			goto err_out;
@@ -146,8 +147,9 @@ static int erofs_map_blocks_flatmode(struct inode *inode,
 
 		map->m_flags |= EROFS_MAP_META;
 	} else {
-		errln("internal error @ nid: %llu (size %llu), m_la 0x%llx",
-		      vi->nid, inode->i_size, map->m_la);
+		erofs_err(inode->i_sb,
+			  "internal error @ nid: %llu (size %llu), m_la 0x%llx",
+			  vi->nid, inode->i_size, map->m_la);
 		DBG_BUGON(1);
 		err = -EIO;
 		goto err_out;
diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
index 37177d49d125..19f89f9fb10c 100644
--- a/fs/erofs/decompressor.c
+++ b/fs/erofs/decompressor.c
@@ -161,9 +161,8 @@ static int z_erofs_lz4_decompress(struct z_erofs_decompress_req *rq, u8 *out)
 					  inlen, rq->outputsize,
 					  rq->outputsize);
 	if (ret < 0) {
-		errln("%s, failed to decompress, in[%p, %u, %u] out[%p, %u]",
-		      __func__, src + inputmargin, inlen, inputmargin,
-		      out, rq->outputsize);
+		erofs_err(rq->sb, "failed to decompress, in[%u, %u] out[%u]",
+			  inlen, inputmargin, rq->outputsize);
 		WARN_ON(1);
 		print_hex_dump(KERN_DEBUG, "[ in]: ", DUMP_PREFIX_OFFSET,
 			       16, 1, src + inputmargin, inlen, true);
diff --git a/fs/erofs/dir.c b/fs/erofs/dir.c
index a032c8217071..d28c623dfef9 100644
--- a/fs/erofs/dir.c
+++ b/fs/erofs/dir.c
@@ -16,8 +16,8 @@ static void debug_one_dentry(unsigned char d_type, const char *de_name,
 	memcpy(dbg_namebuf, de_name, de_namelen);
 	dbg_namebuf[de_namelen] = '\0';
 
-	debugln("found dirent %s de_len %u d_type %d", dbg_namebuf,
-		de_namelen, d_type);
+	erofs_dbg("found dirent %s de_len %u d_type %d", dbg_namebuf,
+		  de_namelen, d_type);
 #endif
 }
 
@@ -47,7 +47,8 @@ static int erofs_fill_dentries(struct inode *dir, struct dir_context *ctx,
 		/* a corrupted entry is found */
 		if (nameoff + de_namelen > maxsize ||
 		    de_namelen > EROFS_NAME_LEN) {
-			errln("bogus dirent @ nid %llu", EROFS_I(dir)->nid);
+			erofs_err(dir->i_sb, "bogus dirent @ nid %llu",
+				  EROFS_I(dir)->nid);
 			DBG_BUGON(1);
 			return -EFSCORRUPTED;
 		}
@@ -84,8 +85,9 @@ static int erofs_readdir(struct file *f, struct dir_context *ctx)
 			err = -ENOMEM;
 			break;
 		} else if (IS_ERR(dentry_page)) {
-			errln("fail to readdir of logical block %u of nid %llu",
-			      i, EROFS_I(dir)->nid);
+			erofs_err(dir->i_sb,
+				  "fail to readdir of logical block %u of nid %llu",
+				  i, EROFS_I(dir)->nid);
 			err = -EFSCORRUPTED;
 			break;
 		}
@@ -96,8 +98,9 @@ static int erofs_readdir(struct file *f, struct dir_context *ctx)
 
 		if (nameoff < sizeof(struct erofs_dirent) ||
 		    nameoff >= PAGE_SIZE) {
-			errln("%s, invalid de[0].nameoff %u @ nid %llu",
-			      __func__, nameoff, EROFS_I(dir)->nid);
+			erofs_err(dir->i_sb,
+				  "invalid de[0].nameoff %u @ nid %llu",
+				  nameoff, EROFS_I(dir)->nid);
 			err = -EFSCORRUPTED;
 			goto skip_this;
 		}
diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index 5a6d3282fefb..a0cec3c754cd 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -22,8 +22,8 @@ static int erofs_read_inode(struct inode *inode, void *data)
 	vi->datalayout = erofs_inode_datalayout(ifmt);
 
 	if (vi->datalayout >= EROFS_INODE_DATALAYOUT_MAX) {
-		errln("unsupported datalayout %u of nid %llu",
-		      vi->datalayout, vi->nid);
+		erofs_err(inode->i_sb, "unsupported datalayout %u of nid %llu",
+			  vi->datalayout, vi->nid);
 		DBG_BUGON(1);
 		return -EOPNOTSUPP;
 	}
@@ -108,8 +108,9 @@ static int erofs_read_inode(struct inode *inode, void *data)
 			nblks = le32_to_cpu(dic->i_u.compressed_blocks);
 		break;
 	default:
-		errln("unsupported on-disk inode version %u of nid %llu",
-		      erofs_inode_version(ifmt), vi->nid);
+		erofs_err(inode->i_sb,
+			  "unsupported on-disk inode version %u of nid %llu",
+			  erofs_inode_version(ifmt), vi->nid);
 		DBG_BUGON(1);
 		return -EOPNOTSUPP;
 	}
@@ -122,7 +123,8 @@ static int erofs_read_inode(struct inode *inode, void *data)
 	return 0;
 
 bogusimode:
-	errln("bogus i_mode (%o) @ nid %llu", inode->i_mode, vi->nid);
+	erofs_err(inode->i_sb, "bogus i_mode (%o) @ nid %llu",
+		  inode->i_mode, vi->nid);
 	DBG_BUGON(1);
 	return -EFSCORRUPTED;
 }
@@ -148,8 +150,9 @@ static int erofs_fill_symlink(struct inode *inode, void *data,
 	/* inline symlink data shouldn't cross page boundary as well */
 	if (m_pofs + inode->i_size > PAGE_SIZE) {
 		kfree(lnk);
-		errln("inline data cross block boundary @ nid %llu",
-		      vi->nid);
+		erofs_err(inode->i_sb,
+			  "inline data cross block boundary @ nid %llu",
+			  vi->nid);
 		DBG_BUGON(1);
 		return -EFSCORRUPTED;
 	}
@@ -164,7 +167,7 @@ static int erofs_fill_symlink(struct inode *inode, void *data,
 
 static int erofs_fill_inode(struct inode *inode, int isdir)
 {
-	struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
+	struct super_block *sb = inode->i_sb;
 	struct erofs_inode *vi = EROFS_I(inode);
 	struct page *page;
 	void *data;
@@ -174,18 +177,18 @@ static int erofs_fill_inode(struct inode *inode, int isdir)
 	erofs_off_t inode_loc;
 
 	trace_erofs_fill_inode(inode, isdir);
-	inode_loc = iloc(sbi, vi->nid);
+	inode_loc = iloc(EROFS_SB(sb), vi->nid);
 	blkaddr = erofs_blknr(inode_loc);
 	ofs = erofs_blkoff(inode_loc);
 
-	debugln("%s, reading inode nid %llu at %u of blkaddr %u",
-		__func__, vi->nid, ofs, blkaddr);
+	erofs_dbg("%s, reading inode nid %llu at %u of blkaddr %u",
+		  __func__, vi->nid, ofs, blkaddr);
 
-	page = erofs_get_meta_page(inode->i_sb, blkaddr);
+	page = erofs_get_meta_page(sb, blkaddr);
 
 	if (IS_ERR(page)) {
-		errln("failed to get inode (nid: %llu) page, err %ld",
-		      vi->nid, PTR_ERR(page));
+		erofs_err(sb, "failed to get inode (nid: %llu) page, err %ld",
+			  vi->nid, PTR_ERR(page));
 		return PTR_ERR(page);
 	}
 
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index d659c1941f93..544a453f3076 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -22,13 +22,19 @@
 #undef pr_fmt
 #define pr_fmt(fmt) "erofs: " fmt
 
-#define errln(x, ...)   pr_err(x "\n", ##__VA_ARGS__)
-#define infoln(x, ...)  pr_info(x "\n", ##__VA_ARGS__)
+__printf(3, 4) void _erofs_err(struct super_block *sb,
+			       const char *function, const char *fmt, ...);
+#define erofs_err(sb, fmt, ...)	\
+	_erofs_err(sb, __func__, fmt "\n", ##__VA_ARGS__)
+__printf(3, 4) void _erofs_info(struct super_block *sb,
+			       const char *function, const char *fmt, ...);
+#define erofs_info(sb, fmt, ...) \
+	_erofs_info(sb, __func__, fmt "\n", ##__VA_ARGS__)
 #ifdef CONFIG_EROFS_FS_DEBUG
-#define debugln(x, ...) pr_debug(x "\n", ##__VA_ARGS__)
+#define erofs_dbg(x, ...)       pr_debug(x "\n", ##__VA_ARGS__)
 #define DBG_BUGON               BUG_ON
 #else
-#define debugln(x, ...)         ((void)0)
+#define erofs_dbg(x, ...)       ((void)0)
 #define DBG_BUGON(x)            ((void)(x))
 #endif	/* !CONFIG_EROFS_FS_DEBUG */
 
diff --git a/fs/erofs/namei.c b/fs/erofs/namei.c
index 6debc1d88282..3abbecbf73de 100644
--- a/fs/erofs/namei.c
+++ b/fs/erofs/namei.c
@@ -116,8 +116,9 @@ static struct page *find_target_block_classic(struct inode *dir,
 			if (!ndirents) {
 				kunmap_atomic(de);
 				put_page(page);
-				errln("corrupted dir block %d @ nid %llu",
-				      mid, EROFS_I(dir)->nid);
+				erofs_err(dir->i_sb,
+					  "corrupted dir block %d @ nid %llu",
+					  mid, EROFS_I(dir)->nid);
 				DBG_BUGON(1);
 				page = ERR_PTR(-EFSCORRUPTED);
 				goto out;
@@ -233,8 +234,8 @@ static struct dentry *erofs_lookup(struct inode *dir,
 	} else if (err) {
 		inode = ERR_PTR(err);
 	} else {
-		debugln("%s, %s (nid %llu) found, d_type %u", __func__,
-			dentry->d_name.name, nid, d_type);
+		erofs_dbg("%s, %s (nid %llu) found, d_type %u", __func__,
+			  dentry->d_name.name, nid, d_type);
 		inode = erofs_iget(dir->i_sb, nid, d_type == FT_DIR);
 	}
 	return d_splice_alias(inode, dentry);
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 407c95854be1..1d9880195ef0 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -16,6 +16,36 @@
 
 static struct kmem_cache *erofs_inode_cachep __read_mostly;
 
+void _erofs_err(struct super_block *sb, const char *function,
+		const char *fmt, ...)
+{
+	struct va_format vaf;
+	va_list args;
+
+	va_start(args, fmt);
+
+	vaf.fmt = fmt;
+	vaf.va = &args;
+
+	pr_err("(device %s): %s: %pV", sb->s_id, function, &vaf);
+	va_end(args);
+}
+
+void _erofs_info(struct super_block *sb, const char *function,
+		 const char *fmt, ...)
+{
+	struct va_format vaf;
+	va_list args;
+
+	va_start(args, fmt);
+
+	vaf.fmt = fmt;
+	vaf.va = &args;
+
+	pr_info("(device %s): %pV", sb->s_id, &vaf);
+	va_end(args);
+}
+
 static void erofs_inode_init_once(void *ptr)
 {
 	struct erofs_inode *vi = ptr;
@@ -57,8 +87,9 @@ static bool check_layout_compatibility(struct super_block *sb,
 
 	/* check if current kernel meets all mandatory requirements */
 	if (feature & (~EROFS_ALL_FEATURE_INCOMPAT)) {
-		errln("unidentified incompatible feature %x, please upgrade kernel version",
-		      feature & ~EROFS_ALL_FEATURE_INCOMPAT);
+		erofs_err(sb,
+			  "unidentified incompatible feature %x, please upgrade kernel version",
+			   feature & ~EROFS_ALL_FEATURE_INCOMPAT);
 		return false;
 	}
 	return true;
@@ -75,7 +106,7 @@ static int erofs_read_superblock(struct super_block *sb)
 	bh = sb_bread(sb, 0);
 
 	if (!bh) {
-		errln("cannot read erofs superblock");
+		erofs_err(sb, "cannot read erofs superblock");
 		return -EIO;
 	}
 
@@ -84,15 +115,15 @@ static int erofs_read_superblock(struct super_block *sb)
 
 	ret = -EINVAL;
 	if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) {
-		errln("cannot find valid erofs superblock");
+		erofs_err(sb, "cannot find valid erofs superblock");
 		goto out;
 	}
 
 	blkszbits = dsb->blkszbits;
 	/* 9(512 bytes) + LOG_SECTORS_PER_BLOCK == LOG_BLOCK_SIZE */
 	if (blkszbits != LOG_BLOCK_SIZE) {
-		errln("blksize %u isn't supported on this platform",
-		      1 << blkszbits);
+		erofs_err(sb, "blksize %u isn't supported on this platform",
+			  1 << blkszbits);
 		goto out;
 	}
 
@@ -116,7 +147,7 @@ static int erofs_read_superblock(struct super_block *sb)
 	ret = strscpy(sbi->volume_name, dsb->volume_name,
 		      sizeof(dsb->volume_name));
 	if (ret < 0) {	/* -E2BIG */
-		errln("bad volume name without NIL terminator");
+		erofs_err(sb, "bad volume name without NIL terminator");
 		ret = -EFSCORRUPTED;
 		goto out;
 	}
@@ -127,14 +158,15 @@ static int erofs_read_superblock(struct super_block *sb)
 }
 
 #ifdef CONFIG_EROFS_FS_ZIP
-static int erofs_build_cache_strategy(struct erofs_sb_info *sbi,
+static int erofs_build_cache_strategy(struct super_block *sb,
 				      substring_t *args)
 {
+	struct erofs_sb_info *sbi = EROFS_SB(sb);
 	const char *cs = match_strdup(args);
 	int err = 0;
 
 	if (!cs) {
-		errln("Not enough memory to store cache strategy");
+		erofs_err(sb, "Not enough memory to store cache strategy");
 		return -ENOMEM;
 	}
 
@@ -145,17 +177,17 @@ static int erofs_build_cache_strategy(struct erofs_sb_info *sbi,
 	} else if (!strcmp(cs, "readaround")) {
 		sbi->cache_strategy = EROFS_ZIP_CACHE_READAROUND;
 	} else {
-		errln("Unrecognized cache strategy \"%s\"", cs);
+		erofs_err(sb, "Unrecognized cache strategy \"%s\"", cs);
 		err = -EINVAL;
 	}
 	kfree(cs);
 	return err;
 }
 #else
-static int erofs_build_cache_strategy(struct erofs_sb_info *sbi,
+static int erofs_build_cache_strategy(struct super_block *sb,
 				      substring_t *args)
 {
-	infoln("EROFS compression is disabled, so cache strategy is ignored");
+	erofs_info(sb, "EROFS compression is disabled, so cache strategy is ignored");
 	return 0;
 }
 #endif
@@ -221,10 +253,10 @@ static int erofs_parse_options(struct super_block *sb, char *options)
 			break;
 #else
 		case Opt_user_xattr:
-			infoln("user_xattr options not supported");
+			erofs_info(sb, "user_xattr options not supported");
 			break;
 		case Opt_nouser_xattr:
-			infoln("nouser_xattr options not supported");
+			erofs_info(sb, "nouser_xattr options not supported");
 			break;
 #endif
 #ifdef CONFIG_EROFS_FS_POSIX_ACL
@@ -236,19 +268,19 @@ static int erofs_parse_options(struct super_block *sb, char *options)
 			break;
 #else
 		case Opt_acl:
-			infoln("acl options not supported");
+			erofs_info(sb, "acl options not supported");
 			break;
 		case Opt_noacl:
-			infoln("noacl options not supported");
+			erofs_info(sb, "noacl options not supported");
 			break;
 #endif
 		case Opt_cache_strategy:
-			err = erofs_build_cache_strategy(EROFS_SB(sb), args);
+			err = erofs_build_cache_strategy(sb, args);
 			if (err)
 				return err;
 			break;
 		default:
-			errln("Unrecognized mount option \"%s\" or missing value", p);
+			erofs_err(sb, "Unrecognized mount option \"%s\" or missing value", p);
 			return -EINVAL;
 		}
 	}
@@ -323,7 +355,7 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
 	sb->s_magic = EROFS_SUPER_MAGIC;
 
 	if (!sb_set_blocksize(sb, EROFS_BLKSIZ)) {
-		errln("failed to set erofs blksize");
+		erofs_err(sb, "failed to set erofs blksize");
 		return -EINVAL;
 	}
 
@@ -367,8 +399,8 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
 		return PTR_ERR(inode);
 
 	if (!S_ISDIR(inode->i_mode)) {
-		errln("rootino(nid %llu) is not a directory(i_mode %o)",
-		      ROOT_NID(sbi), inode->i_mode);
+		erofs_err(sb, "rootino(nid %llu) is not a directory(i_mode %o)",
+			  ROOT_NID(sbi), inode->i_mode);
 		iput(inode);
 		return -EINVAL;
 	}
@@ -383,9 +415,8 @@ static int erofs_fill_super(struct super_block *sb, void *data, int silent)
 	if (err)
 		return err;
 
-	if (!silent)
-		infoln("mounted on %s with opts: %s, root inode @ nid %llu.",
-		       sb->s_id, (char *)data, ROOT_NID(sbi));
+	erofs_info(sb, "mounted with opts: %s, root inode @ nid %llu.",
+		   (char *)data, ROOT_NID(sbi));
 	return 0;
 }
 
@@ -404,7 +435,6 @@ static void erofs_kill_sb(struct super_block *sb)
 	struct erofs_sb_info *sbi;
 
 	WARN_ON(sb->s_magic != EROFS_SUPER_MAGIC);
-	infoln("unmounting for %s", sb->s_id);
 
 	kill_block_super(sb);
 
@@ -443,7 +473,6 @@ static int __init erofs_module_init(void)
 	int err;
 
 	erofs_check_ondisk_layout_definitions();
-	infoln("initializing erofs " EROFS_VERSION);
 
 	erofs_inode_cachep = kmem_cache_create("erofs_inode",
 					       sizeof(struct erofs_inode), 0,
@@ -466,7 +495,6 @@ static int __init erofs_module_init(void)
 	if (err)
 		goto fs_err;
 
-	infoln("successfully to initialize erofs");
 	return 0;
 
 fs_err:
@@ -488,7 +516,6 @@ static void __exit erofs_module_exit(void)
 	/* Ensure all RCU free inodes are safe before cache is destroyed. */
 	rcu_barrier();
 	kmem_cache_destroy(erofs_inode_cachep);
-	infoln("successfully finalize erofs");
 }
 
 /* get filesystem statistics */
diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c
index dd445c81c41f..a13a78725c57 100644
--- a/fs/erofs/xattr.c
+++ b/fs/erofs/xattr.c
@@ -67,13 +67,15 @@ static int init_inode_xattrs(struct inode *inode)
 	 *    undefined right now (maybe use later with some new sb feature).
 	 */
 	if (vi->xattr_isize == sizeof(struct erofs_xattr_ibody_header)) {
-		errln("xattr_isize %d of nid %llu is not supported yet",
-		      vi->xattr_isize, vi->nid);
+		erofs_err(inode->i_sb,
+			  "xattr_isize %d of nid %llu is not supported yet",
+			  vi->xattr_isize, vi->nid);
 		ret = -EOPNOTSUPP;
 		goto out_unlock;
 	} else if (vi->xattr_isize < sizeof(struct erofs_xattr_ibody_header)) {
 		if (vi->xattr_isize) {
-			errln("bogus xattr ibody @ nid %llu", vi->nid);
+			erofs_err(inode->i_sb,
+				  "bogus xattr ibody @ nid %llu", vi->nid);
 			DBG_BUGON(1);
 			ret = -EFSCORRUPTED;
 			goto out_unlock;	/* xattr ondisk layout error */
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index ff8ab444172d..96e34c90f814 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -600,7 +600,7 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
 	}
 
 	/* go ahead the next map_blocks */
-	debugln("%s: [out-of-range] pos %llu", __func__, offset + cur);
+	erofs_dbg("%s: [out-of-range] pos %llu", __func__, offset + cur);
 
 	if (z_erofs_collector_end(clt))
 		fe->backmost = false;
@@ -680,8 +680,8 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe,
 out:
 	z_erofs_onlinepage_endio(page);
 
-	debugln("%s, finish page: %pK spiltted: %u map->m_llen %llu",
-		__func__, page, spiltted, map->m_llen);
+	erofs_dbg("%s, finish page: %pK spiltted: %u map->m_llen %llu",
+		  __func__, page, spiltted, map->m_llen);
 	return err;
 
 	/* if some error occurred while processing this page */
@@ -1340,7 +1340,7 @@ static int z_erofs_vle_normalaccess_readpage(struct file *file,
 	z_erofs_submit_and_unzip(inode->i_sb, &f.clt, &pagepool, true);
 
 	if (err)
-		errln("%s, failed to read, err [%d]", __func__, err);
+		erofs_err(inode->i_sb, "failed to read, err [%d]", err);
 
 	if (f.map.mpage)
 		put_page(f.map.mpage);
@@ -1406,8 +1406,9 @@ static int z_erofs_vle_normalaccess_readpages(struct file *filp,
 
 		err = z_erofs_do_read_page(&f, page, &pagepool);
 		if (err)
-			errln("%s, readahead error at page %lu of nid %llu",
-			      __func__, page->index, EROFS_I(inode)->nid);
+			erofs_err(inode->i_sb,
+				  "readahead error at page %lu @ nid %llu",
+				  page->index, EROFS_I(inode)->nid);
 		put_page(page);
 	}
 
diff --git a/fs/erofs/zdata.h b/fs/erofs/zdata.h
index 4fc547bc01f9..faf950189bd7 100644
--- a/fs/erofs/zdata.h
+++ b/fs/erofs/zdata.h
@@ -182,7 +182,7 @@ static inline void z_erofs_onlinepage_endio(struct page *page)
 			SetPageUptodate(page);
 		unlock_page(page);
 	}
-	debugln("%s, page %p value %x", __func__, page, atomic_read(u.o));
+	erofs_dbg("%s, page %p value %x", __func__, page, atomic_read(u.o));
 }
 
 #define Z_EROFS_VMAP_ONSTACK_PAGES	\
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index 9c141f145508..6a26c293ae2d 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -64,8 +64,8 @@ static int fill_inode_lazy(struct inode *inode)
 	vi->z_algorithmtype[1] = h->h_algorithmtype >> 4;
 
 	if (vi->z_algorithmtype[0] >= Z_EROFS_COMPRESSION_MAX) {
-		errln("unknown compression format %u for nid %llu, please upgrade kernel",
-		      vi->z_algorithmtype[0], vi->nid);
+		erofs_err(sb, "unknown compression format %u for nid %llu, please upgrade kernel",
+			  vi->z_algorithmtype[0], vi->nid);
 		err = -EOPNOTSUPP;
 		goto unmap_done;
 	}
@@ -75,8 +75,8 @@ static int fill_inode_lazy(struct inode *inode)
 					((h->h_clusterbits >> 3) & 3);
 
 	if (vi->z_physical_clusterbits[0] != LOG_BLOCK_SIZE) {
-		errln("unsupported physical clusterbits %u for nid %llu, please upgrade kernel",
-		      vi->z_physical_clusterbits[0], vi->nid);
+		erofs_err(sb, "unsupported physical clusterbits %u for nid %llu, please upgrade kernel",
+			  vi->z_physical_clusterbits[0], vi->nid);
 		err = -EOPNOTSUPP;
 		goto unmap_done;
 	}
@@ -335,7 +335,8 @@ static int vle_extent_lookback(struct z_erofs_maprecorder *m,
 	int err;
 
 	if (lcn < lookback_distance) {
-		errln("bogus lookback distance @ nid %llu", vi->nid);
+		erofs_err(m->inode->i_sb,
+			  "bogus lookback distance @ nid %llu", vi->nid);
 		DBG_BUGON(1);
 		return -EFSCORRUPTED;
 	}
@@ -349,8 +350,9 @@ static int vle_extent_lookback(struct z_erofs_maprecorder *m,
 	switch (m->type) {
 	case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
 		if (!m->delta[0]) {
-			errln("invalid lookback distance 0 at nid %llu",
-			      vi->nid);
+			erofs_err(m->inode->i_sb,
+				  "invalid lookback distance 0 @ nid %llu",
+				  vi->nid);
 			DBG_BUGON(1);
 			return -EFSCORRUPTED;
 		}
@@ -362,8 +364,9 @@ static int vle_extent_lookback(struct z_erofs_maprecorder *m,
 		map->m_la = (lcn << lclusterbits) | m->clusterofs;
 		break;
 	default:
-		errln("unknown type %u at lcn %lu of nid %llu",
-		      m->type, lcn, vi->nid);
+		erofs_err(m->inode->i_sb,
+			  "unknown type %u @ lcn %lu of nid %llu",
+			  m->type, lcn, vi->nid);
 		DBG_BUGON(1);
 		return -EOPNOTSUPP;
 	}
@@ -421,8 +424,9 @@ int z_erofs_map_blocks_iter(struct inode *inode,
 		}
 		/* m.lcn should be >= 1 if endoff < m.clusterofs */
 		if (!m.lcn) {
-			errln("invalid logical cluster 0 at nid %llu",
-			      vi->nid);
+			erofs_err(inode->i_sb,
+				  "invalid logical cluster 0 at nid %llu",
+				  vi->nid);
 			err = -EFSCORRUPTED;
 			goto unmap_out;
 		}
@@ -437,8 +441,9 @@ int z_erofs_map_blocks_iter(struct inode *inode,
 			goto unmap_out;
 		break;
 	default:
-		errln("unknown type %u at offset %llu of nid %llu",
-		      m.type, ofs, vi->nid);
+		erofs_err(inode->i_sb,
+			  "unknown type %u @ offset %llu of nid %llu",
+			  m.type, ofs, vi->nid);
 		err = -EOPNOTSUPP;
 		goto unmap_out;
 	}
@@ -453,9 +458,9 @@ int z_erofs_map_blocks_iter(struct inode *inode,
 		kunmap_atomic(m.kaddr);
 
 out:
-	debugln("%s, m_la %llu m_pa %llu m_llen %llu m_plen %llu m_flags 0%o",
-		__func__, map->m_la, map->m_pa,
-		map->m_llen, map->m_plen, map->m_flags);
+	erofs_dbg("%s, m_la %llu m_pa %llu m_llen %llu m_plen %llu m_flags 0%o",
+		  __func__, map->m_la, map->m_pa,
+		  map->m_llen, map->m_plen, map->m_flags);
 
 	trace_z_erofs_map_blocks_iter_exit(inode, map, flags, err);
 
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v2 23/25] erofs: use read_mapping_page instead of sb_bread
  2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
                       ` (21 preceding siblings ...)
  2019-09-04  2:09     ` [PATCH v2 22/25] erofs: rename errln/infoln/debugln to erofs_{err,info,dbg} Gao Xiang
@ 2019-09-04  2:09     ` Gao Xiang
  2019-09-04  2:09     ` [PATCH v2 24/25] erofs: always use iget5_locked Gao Xiang
                       ` (3 subsequent siblings)
  26 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-04  2:09 UTC (permalink / raw)
  To: Chao Yu, Greg Kroah-Hartman, Christoph Hellwig, devel
  Cc: linux-fsdevel, linux-erofs, Chao Yu, Miao Xie, Gao Xiang

As Christoph said [1], "This seems to be your only direct
use of buffer heads, which while not deprecated are a bit
of an ugly step child.  So if you can easily avoid creating
a buffer_head dependency in a new filesystem I think you
should avoid it. "

[1] https://lore.kernel.org/r/20190902125109.GA9826@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/super.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 1d9880195ef0..caf9a95173b0 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -98,20 +98,22 @@ static bool check_layout_compatibility(struct super_block *sb,
 static int erofs_read_superblock(struct super_block *sb)
 {
 	struct erofs_sb_info *sbi;
-	struct buffer_head *bh;
+	struct page *page;
 	struct erofs_super_block *dsb;
 	unsigned int blkszbits;
+	void *data;
 	int ret;
 
-	bh = sb_bread(sb, 0);
-
-	if (!bh) {
+	page = read_mapping_page(sb->s_bdev->bd_inode->i_mapping, 0, NULL);
+	if (!page) {
 		erofs_err(sb, "cannot read erofs superblock");
 		return -EIO;
 	}
 
 	sbi = EROFS_SB(sb);
-	dsb = (struct erofs_super_block *)(bh->b_data + EROFS_SUPER_OFFSET);
+
+	data = kmap_atomic(page);
+	dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET);
 
 	ret = -EINVAL;
 	if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) {
@@ -153,7 +155,8 @@ static int erofs_read_superblock(struct super_block *sb)
 	}
 	ret = 0;
 out:
-	brelse(bh);
+	kunmap_atomic(data);
+	put_page(page);
 	return ret;
 }
 
-- 
2.17.1


^ permalink raw reply	[flat|nested] 159+ messages in thread

* [PATCH v2 24/25] erofs: always use iget5_locked
  2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
                       ` (22 preceding siblings ...)
  2019-09-04  2:09     ` [PATCH v2 23/25] erofs: use read_mapping_page instead of sb_bread Gao Xiang
@ 2019-09-04  2:09     ` Gao Xiang
  2019-09-04  2:09     ` [PATCH v2 25/25] erofs: use read_cache_page_gfp for erofs_get_meta_page Gao Xiang
                       ` (2 subsequent siblings)
  26 siblings, 0 replies; 159+ messages in thread
From: Gao Xiang @ 2019-09-04  2:09 UTC (permalink / raw)
  To: Chao Yu, Greg Kroah-Hartman, Christoph Hellwig, devel
  Cc: linux-fsdevel, linux-erofs, Chao Yu, M