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* [PATCH 1/3] fs/erofs: new filesystem
@ 2021-08-22 15:48 Huang Jianan
  2021-08-22 15:48 ` [PATCH 2/3] fs/erofs: add lz4 1.8.3 decompressor Huang Jianan
                   ` (3 more replies)
  0 siblings, 4 replies; 18+ messages in thread
From: Huang Jianan @ 2021-08-22 15:48 UTC (permalink / raw)
  To: u-boot; +Cc: xiang, linux-erofs

From: Huang Jianan <huangjianan@oppo.com>

Add erofs filesystem support.

The code is adapted from erofs-utils in order to reduce maintenance
burden and keep with the latest feature.

This patch mainly deals with uncompressed files.

Signed-off-by: Huang Jianan <jnhuang95@gmail.com>
---
 fs/Kconfig          |   1 +
 fs/Makefile         |   1 +
 fs/erofs/Kconfig    |  12 ++
 fs/erofs/Makefile   |   7 +
 fs/erofs/data.c     | 124 ++++++++++++++
 fs/erofs/erofs_fs.h | 384 ++++++++++++++++++++++++++++++++++++++++++++
 fs/erofs/fs.c       | 230 ++++++++++++++++++++++++++
 fs/erofs/internal.h | 203 +++++++++++++++++++++++
 fs/erofs/namei.c    | 238 +++++++++++++++++++++++++++
 fs/erofs/super.c    |  65 ++++++++
 fs/fs.c             |  22 +++
 include/erofs.h     |  19 +++
 include/fs.h        |   1 +
 13 files changed, 1307 insertions(+)
 create mode 100644 fs/erofs/Kconfig
 create mode 100644 fs/erofs/Makefile
 create mode 100644 fs/erofs/data.c
 create mode 100644 fs/erofs/erofs_fs.h
 create mode 100644 fs/erofs/fs.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 include/erofs.h

diff --git a/fs/Kconfig b/fs/Kconfig
index 620af7f044..4d04c2c2ce 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -24,4 +24,5 @@ source "fs/yaffs2/Kconfig"
 
 source "fs/squashfs/Kconfig"
 
+source "fs/erofs/Kconfig"
 endmenu
diff --git a/fs/Makefile b/fs/Makefile
index 937cbcf6e8..f05a21c9e6 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -25,5 +25,6 @@ obj-$(CONFIG_CMD_UBIFS) += ubifs/
 obj-$(CONFIG_YAFFS2) += yaffs2/
 obj-$(CONFIG_CMD_ZFS) += zfs/
 obj-$(CONFIG_FS_SQUASHFS) += squashfs/
+obj-$(CONFIG_FS_EROFS) += erofs/
 endif
 obj-y += fs_internal.o
diff --git a/fs/erofs/Kconfig b/fs/erofs/Kconfig
new file mode 100644
index 0000000000..f4b2d51a23
--- /dev/null
+++ b/fs/erofs/Kconfig
@@ -0,0 +1,12 @@
+config FS_EROFS
+	bool "Enable EROFS filesystem support"
+	help
+	  This provides support for reading images from EROFS filesystem.
+	  EROFS (Enhanced Read-Only File System) is a lightweight read-only
+	  file system for scenarios which need high-performance read-only
+	  requirements.
+
+	  It also provides fixed-sized output compression support, which
+	  improves storage density, keeps relatively higher compression
+	  ratios, which is more useful to achieve high performance for
+	  embedded devices with limited memory.
diff --git a/fs/erofs/Makefile b/fs/erofs/Makefile
new file mode 100644
index 0000000000..7398ab7a36
--- /dev/null
+++ b/fs/erofs/Makefile
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+
+obj-$(CONFIG_$(SPL_)FS_EROFS) = fs.o \
+				super.o \
+				namei.o \
+				data.o
diff --git a/fs/erofs/data.c b/fs/erofs/data.c
new file mode 100644
index 0000000000..a0f613264a
--- /dev/null
+++ b/fs/erofs/data.c
@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include "internal.h"
+
+static int erofs_map_blocks_flatmode(struct erofs_inode *inode,
+				     struct erofs_map_blocks *map,
+				     int flags)
+{
+	int err = 0;
+	erofs_blk_t nblocks, lastblk;
+	u64 offset = map->m_la;
+	struct erofs_inode *vi = inode;
+	bool tailendpacking = (vi->datalayout == EROFS_INODE_FLAT_INLINE);
+
+	nblocks = DIV_ROUND_UP(inode->i_size, EROFS_BLKSIZ);
+	lastblk = nblocks - tailendpacking;
+
+	if (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->u.i_blkaddr) + map->m_la;
+		map->m_plen = blknr_to_addr(lastblk) - offset;
+	} else if (tailendpacking) {
+		/* 2 - inode inline B: inode, [xattrs], inline last blk... */
+		map->m_pa = iloc(vi->nid) + vi->inode_isize +
+			vi->xattr_isize + erofs_blkoff(map->m_la);
+		map->m_plen = inode->i_size - offset;
+
+		/* inline data should be located in one meta block */
+		if (erofs_blkoff(map->m_pa) + map->m_plen > PAGE_SIZE) {
+			erofs_err("inline data cross block boundary @ nid %" PRIu64,
+				  vi->nid);
+			DBG_BUGON(1);
+			err = -EFSCORRUPTED;
+			goto err_out;
+		}
+
+		map->m_flags |= EROFS_MAP_META;
+	} else {
+		erofs_err("internal error @ nid: %" PRIu64 " (size %llu), m_la 0x%" PRIx64,
+			  vi->nid, (unsigned long long)inode->i_size, map->m_la);
+		DBG_BUGON(1);
+		err = -EIO;
+		goto err_out;
+	}
+
+out:
+	map->m_llen = map->m_plen;
+
+err_out:
+	return err;
+}
+
+static int erofs_read_raw_data(struct erofs_inode *inode, char *buffer,
+			       erofs_off_t size, erofs_off_t offset)
+{
+	struct erofs_map_blocks map = {
+		.index = UINT_MAX,
+	};
+	int ret;
+	erofs_off_t ptr = offset;
+
+	while (ptr < offset + size) {
+		char *const estart = buffer + ptr - offset;
+		erofs_off_t eend;
+
+		map.m_la = ptr;
+		ret = erofs_map_blocks_flatmode(inode, &map, 0);
+		if (ret)
+			return ret;
+
+		DBG_BUGON(map.m_plen != map.m_llen);
+
+		/* trim extent */
+		eend = min(offset + size, map.m_la + map.m_llen);
+		DBG_BUGON(ptr < map.m_la);
+
+		if (!(map.m_flags & EROFS_MAP_MAPPED)) {
+			if (!map.m_llen) {
+				/* reached EOF */
+				memset(estart, 0, offset + size - ptr);
+				ptr = offset + size;
+				continue;
+			}
+			memset(estart, 0, eend - ptr);
+			ptr = eend;
+			continue;
+		}
+
+		if (ptr > map.m_la) {
+			map.m_pa += ptr - map.m_la;
+			map.m_la = ptr;
+		}
+
+		ret = erofs_dev_read(estart, map.m_pa, eend - map.m_la);
+		if (ret < 0)
+			return -EIO;
+		ptr = eend;
+	}
+	return 0;
+}
+
+int erofs_pread(struct erofs_inode *inode, char *buf,
+		erofs_off_t count, erofs_off_t offset)
+{
+	switch (inode->datalayout) {
+	case EROFS_INODE_FLAT_PLAIN:
+	case EROFS_INODE_FLAT_INLINE:
+		return erofs_read_raw_data(inode, buf, count, offset);
+	case EROFS_INODE_FLAT_COMPRESSION_LEGACY:
+	case EROFS_INODE_FLAT_COMPRESSION:
+		return -EOPNOTSUPP;
+	default:
+		break;
+	}
+	return -EINVAL;
+}
diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
new file mode 100644
index 0000000000..070087fa60
--- /dev/null
+++ b/fs/erofs/erofs_fs.h
@@ -0,0 +1,384 @@
+/* SPDX-License-Identifier: GPL-2.0+ OR Apache-2.0 */
+/*
+ * EROFS (Enhanced ROM File System) on-disk format definition
+ *
+ * Copyright (C) 2017-2018 HUAWEI, Inc.
+ *             http://www.huawei.com/
+ */
+#ifndef __EROFS_FS_H
+#define __EROFS_FS_H
+
+#include <asm/unaligned.h>
+#include <fs.h>
+#include <part.h>
+#include <stdint.h>
+
+#define EROFS_SUPER_MAGIC_V1    0xE0F5E1E2
+#define EROFS_SUPER_OFFSET      1024
+
+#define EROFS_FEATURE_COMPAT_SB_CHKSUM          0x00000001
+
+/*
+ * Any bits that aren't in EROFS_ALL_FEATURE_INCOMPAT should
+ * be incompatible with this kernel version.
+ */
+#define EROFS_FEATURE_INCOMPAT_LZ4_0PADDING	0x00000001
+#define EROFS_FEATURE_INCOMPAT_COMPR_CFGS	0x00000002
+#define EROFS_FEATURE_INCOMPAT_BIG_PCLUSTER	0x00000002
+#define EROFS_ALL_FEATURE_INCOMPAT		\
+	(EROFS_FEATURE_INCOMPAT_LZ4_0PADDING | \
+	 EROFS_FEATURE_INCOMPAT_COMPR_CFGS | \
+	 EROFS_FEATURE_INCOMPAT_BIG_PCLUSTER)
+
+#define EROFS_SB_EXTSLOT_SIZE	16
+
+/* erofs on-disk super block (currently 128 bytes) */
+struct erofs_super_block {
+	__le32 magic;           /* file system magic number */
+	__le32 checksum;        /* crc32c(super_block) */
+	__le32 feature_compat;
+	__u8 blkszbits;         /* support block_size == PAGE_SIZE only */
+	__u8 sb_extslots;	/* superblock size = 128 + sb_extslots * 16 */
+
+	__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 feature_incompat;
+	union {
+		/* bitmap for available compression algorithms */
+		__le16 available_compr_algs;
+		/* customized sliding window size instead of 64k by default */
+		__le16 lz4_max_distance;
+	} __packed u1;
+	__u8 reserved2[42];
+};
+
+/*
+ * 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):
+ * 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 - inode chunk-based E:
+ * inode, [xattrs], chunk indexes ... | ...
+ * 5~7 - reserved
+ */
+enum {
+	EROFS_INODE_FLAT_PLAIN			= 0,
+	EROFS_INODE_FLAT_COMPRESSION_LEGACY	= 1,
+	EROFS_INODE_FLAT_INLINE			= 2,
+	EROFS_INODE_FLAT_COMPRESSION		= 3,
+	EROFS_INODE_CHUNK_BASED			= 4,
+	EROFS_INODE_DATALAYOUT_MAX
+};
+
+static inline bool erofs_inode_is_data_compressed(unsigned int datamode)
+{
+	return datamode == EROFS_INODE_FLAT_COMPRESSION ||
+		datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY;
+}
+
+/* bit definitions of inode i_advise */
+#define EROFS_I_VERSION_BITS            1
+#define EROFS_I_DATALAYOUT_BITS         3
+
+#define EROFS_I_VERSION_BIT             0
+#define EROFS_I_DATALAYOUT_BIT          1
+
+#define EROFS_I_ALL	\
+	((1 << (EROFS_I_DATALAYOUT_BIT + EROFS_I_DATALAYOUT_BITS)) - 1)
+
+/* indicate chunk blkbits, thus 'chunksize = blocksize << chunk blkbits' */
+#define EROFS_CHUNK_FORMAT_BLKBITS_MASK		0x001F
+/* with chunk indexes or just a 4-byte blkaddr array */
+#define EROFS_CHUNK_FORMAT_INDEXES		0x0020
+
+#define EROFS_CHUNK_FORMAT_ALL	\
+	(EROFS_CHUNK_FORMAT_BLKBITS_MASK | EROFS_CHUNK_FORMAT_INDEXES)
+
+struct erofs_inode_chunk_info {
+	__le16 format;		/* chunk blkbits, etc. */
+	__le16 reserved;
+};
+
+/* 32-byte reduced form of an ondisk inode */
+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;
+	__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;
+
+		/* for device files, used to indicate old/new device # */
+		__le32 rdev;
+
+		/* for chunk-based files, it contains the summary info */
+		struct erofs_inode_chunk_info c;
+	} i_u;
+	__le32 i_ino;           /* only used for 32-bit stat compatibility */
+	__le16 i_uid;
+	__le16 i_gid;
+	__le32 i_reserved2;
+};
+
+/* 32 bytes on-disk inode */
+#define EROFS_INODE_LAYOUT_COMPACT	0
+/* 64 bytes on-disk inode */
+#define EROFS_INODE_LAYOUT_EXTENDED	1
+
+/* 64-byte complete form of an ondisk inode */
+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;
+	__le16 i_mode;
+	__le16 i_reserved;
+	__le64 i_size;
+	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;
+
+		/* for chunk-based files, it contains the summary info */
+		struct erofs_inode_chunk_info c;
+	} i_u;
+
+	/* only used for 32-bit stat compatibility */
+	__le32 i_ino;
+
+	__le32 i_uid;
+	__le32 i_gid;
+	__le64 i_ctime;
+	__le32 i_ctime_nsec;
+	__le32 i_nlink;
+	__u8   i_reserved2[16];
+};
+
+#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 */
+};
+
+/* 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 */
+};
+
+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))
+
+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));
+}
+
+/* maximum supported size of a physical compression cluster */
+#define Z_EROFS_PCLUSTER_MAX_SIZE	(1024 * 1024)
+
+/* available compression algorithm types (for h_algorithmtype) */
+enum {
+	Z_EROFS_COMPRESSION_LZ4	= 0,
+	Z_EROFS_COMPRESSION_MAX
+};
+#define Z_EROFS_ALL_COMPR_ALGS		(1 << (Z_EROFS_COMPRESSION_MAX - 1))
+
+/* 14 bytes (+ length field = 16 bytes) */
+struct z_erofs_lz4_cfgs {
+	__le16 max_distance;
+	__le16 max_pclusterblks;
+	u8 reserved[10];
+} __packed;
+
+/*
+ * 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.
+ * bit 1 : HEAD1 big pcluster (0 - off; 1 - on)
+ * bit 2 : HEAD2 big pcluster (0 - off; 1 - on)
+ */
+#define Z_EROFS_ADVISE_COMPACTED_2B		0x0001
+#define Z_EROFS_ADVISE_BIG_PCLUSTER_1		0x0002
+#define Z_EROFS_ADVISE_BIG_PCLUSTER_2		0x0004
+
+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 3-7 : reserved.
+	 */
+	__u8	h_clusterbits;
+};
+
+#define Z_EROFS_VLE_LEGACY_HEADER_PADDING       8
+
+/*
+ * 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)
+ *
+ * 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		= 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
+};
+
+#define Z_EROFS_VLE_DI_CLUSTER_TYPE_BITS        2
+#define Z_EROFS_VLE_DI_CLUSTER_TYPE_BIT         0
+
+/*
+ * D0_CBLKCNT will be marked _only_ at the 1st non-head lcluster to store the
+ * compressed block count of a compressed extent (in logical clusters, aka.
+ * block count of a pcluster).
+ */
+#define Z_EROFS_VLE_DI_D0_CBLKCNT		(1 << 11)
+
+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;
+};
+
+#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;     /* node number */
+	__le16 nameoff; /* start offset of file name */
+	__u8 file_type; /* file type */
+	__u8 reserved;  /* 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_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);
+	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/fs/erofs/fs.c b/fs/erofs/fs.c
new file mode 100644
index 0000000000..2c8d20b50d
--- /dev/null
+++ b/fs/erofs/fs.c
@@ -0,0 +1,230 @@
+#include "internal.h"
+#include <fs_internal.h>
+
+struct erofs_sb_info erofs_sbi;
+
+static struct erofs_ctxt {
+	struct disk_partition cur_part_info;
+	struct blk_desc *cur_dev;
+} ctxt;
+
+int erofs_dev_read(void *buf, u64 offset, size_t len)
+{
+	lbaint_t sect = offset >> ctxt.cur_dev->log2blksz;
+	int off = offset & (ctxt.cur_dev->blksz - 1);
+
+	if (!ctxt.cur_dev)
+		return -EIO;
+
+	if (fs_devread(ctxt.cur_dev, &ctxt.cur_part_info, sect,
+			 off, len, buf))
+		return 0;
+	return -EIO;
+}
+
+int erofs_blk_read(void *buf, erofs_blk_t start, u32 nblocks)
+{
+	return erofs_dev_read(buf, blknr_to_addr(start),
+			 blknr_to_addr(nblocks));
+}
+
+int erofs_probe(struct blk_desc *fs_dev_desc,
+		struct disk_partition *fs_partition)
+{
+	int ret;
+
+	ctxt.cur_dev = fs_dev_desc;
+	ctxt.cur_part_info = *fs_partition;
+
+	ret = erofs_read_superblock();
+	if (ret)
+		goto error;
+
+	return 0;
+error:
+	ctxt.cur_dev = NULL;
+	return ret;
+}
+
+struct erofs_dir_stream {
+	struct fs_dir_stream fs_dirs;
+	struct fs_dirent dirent;
+
+	struct erofs_inode inode;
+	char dblk[EROFS_BLKSIZ];
+	unsigned int maxsize, de_end;
+	erofs_off_t pos;
+};
+
+int erofs_opendir(const char *filename, struct fs_dir_stream **dirsp)
+{
+	struct erofs_dir_stream *dirs;
+	int err;
+
+	dirs = calloc(1, sizeof(*dirs));
+	if (!dirs)
+		return -ENOMEM;
+
+	err = erofs_ilookup(filename, &dirs->inode);
+	if (err)
+		goto err_out;
+
+	if (!S_ISDIR(dirs->inode.i_mode)) {
+		err = -ENOTDIR;
+		goto err_out;
+	}
+	*dirsp = (struct fs_dir_stream *)dirs;
+	return 0;
+err_out:
+	free(dirs);
+	return err;
+}
+
+int erofs_readdir(struct fs_dir_stream *fs_dirs, struct fs_dirent **dentp)
+{
+	struct erofs_dir_stream *dirs = (struct erofs_dir_stream *)fs_dirs;
+	struct fs_dirent *dent = &dirs->dirent;
+	erofs_off_t pos = dirs->pos;
+	unsigned int nameoff, de_namelen;
+	struct erofs_dirent *de;
+	char *de_name;
+	int err;
+
+	if (pos >= dirs->inode.i_size)
+		return 1;
+
+	if (!dirs->maxsize) {
+		dirs->maxsize = min_t(unsigned int, EROFS_BLKSIZ,
+				      dirs->inode.i_size - pos);
+
+		err = erofs_pread(&dirs->inode, dirs->dblk,
+				  dirs->maxsize, pos);
+		if (err)
+			return err;
+
+		de = (struct erofs_dirent *)dirs->dblk;
+		dirs->de_end = le16_to_cpu(de->nameoff);
+		if (dirs->de_end < sizeof(struct erofs_dirent) ||
+		    dirs->de_end >= EROFS_BLKSIZ) {
+			erofs_err("invalid de[0].nameoff %u @ nid %llu",
+				  nameoff, de->nid | 0ULL);
+			return -EFSCORRUPTED;
+		}
+	}
+
+	de = (struct erofs_dirent *)(dirs->dblk + erofs_blkoff(pos));
+	nameoff = le16_to_cpu(de->nameoff);
+	de_name = (char *)dirs->dblk + nameoff;
+
+	/* the last dirent in the block? */
+	if (de + 1 >= (struct erofs_dirent *)(dirs->dblk + dirs->de_end))
+		de_namelen = strnlen(de_name, dirs->maxsize - nameoff);
+	else
+		de_namelen = le16_to_cpu(de[1].nameoff) - nameoff;
+
+	/* a corrupted entry is found */
+	if (nameoff + de_namelen > dirs->maxsize ||
+	    de_namelen > EROFS_NAME_LEN) {
+		erofs_err("bogus dirent @ nid %llu", de->nid | 0ULL);
+		DBG_BUGON(1);
+		return -EFSCORRUPTED;
+	}
+
+	memcpy(dent->name, de_name, de_namelen);
+	dent->name[de_namelen] = '\0';
+
+	if (de->file_type == EROFS_FT_DIR) {
+		dent->type = FS_DT_DIR;
+	} else if (de->file_type == EROFS_FT_SYMLINK) {
+		dent->type = FS_DT_LNK;
+	} else {
+		struct erofs_inode vi;
+
+		dent->type = FS_DT_REG;
+		vi.nid = de->nid;
+
+		err = erofs_read_inode_from_disk(&vi);
+		if (err)
+			return err;
+		dent->size = vi.i_size;
+	}
+	*dentp = dent;
+
+	pos += sizeof(*de);
+	if (erofs_blkoff(pos) >= dirs->de_end) {
+		pos = blknr_to_addr(erofs_blknr(pos) + 1);
+		dirs->maxsize = 0;
+	}
+	dirs->pos = pos;
+	return 0;
+}
+
+void erofs_closedir(struct fs_dir_stream *fs_dirs)
+{
+	free(fs_dirs);
+}
+
+int erofs_exists(const char *filename)
+{
+	struct erofs_inode vi;
+	int err;
+
+	err = erofs_ilookup(filename, &vi);
+	return err == 0;
+}
+
+int erofs_size(const char *filename, loff_t *size)
+{
+	struct erofs_inode vi;
+	int err;
+
+	err = erofs_ilookup(filename, &vi);
+	if (err)
+		return err;
+	*size = vi.i_size;
+	return 0;
+}
+
+int erofs_read(const char *filename, void *buf, loff_t offset, loff_t len,
+	      loff_t *actread)
+{
+	struct erofs_inode vi;
+	int err;
+
+	err = erofs_ilookup(filename, &vi);
+	if (err)
+		return err;
+
+	if (!len)
+		len = vi.i_size;
+
+	err = erofs_pread(&vi, buf, len, offset);
+	if (err) {
+		*actread = 0;
+		return err;
+	}
+
+	if (offset >= vi.i_size)
+		*actread = 0;
+	else if (offset + len > vi.i_size)
+		*actread = vi.i_size - offset;
+	else
+		*actread = len;
+	return 0;
+}
+
+void erofs_close(void)
+{
+	ctxt.cur_dev = NULL;
+}
+
+int erofs_uuid(char *uuid_str)
+{
+#ifdef CONFIG_LIB_UUID
+	if (ctxt.cur_dev)
+		uuid_bin_to_str(erofs_sbi.uuid, uuid_str,
+				UUID_STR_FORMAT_STD);
+	return 0;
+#endif
+	return -ENOSYS;
+}
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
new file mode 100644
index 0000000000..02dfd7ead4
--- /dev/null
+++ b/fs/erofs/internal.h
@@ -0,0 +1,203 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+#ifndef __EROFS_INTERNAL_H
+#define __EROFS_INTERNAL_H
+
+#define __packed __attribute__((__packed__))
+
+#include <linux/stat.h>
+#include <linux/bug.h>
+#include <linux/err.h>
+#include <linux/printk.h>
+#include <inttypes.h>
+#include "erofs_fs.h"
+
+#define erofs_err(fmt, ...)	\
+	pr_err(fmt "\n", ##__VA_ARGS__)
+
+#define erofs_info(fmt, ...)	\
+	pr_info(fmt "\n", ##__VA_ARGS__)
+
+#define erofs_dbg(fmt, ...)	\
+	pr_debug(fmt "\n", ##__VA_ARGS__)
+
+#define DBG_BUGON(condition)	BUG_ON(condition)
+
+/* no obvious reason to support explicit PAGE_SIZE != 4096 for now */
+#if PAGE_SIZE != 4096
+#error incompatible PAGE_SIZE is already defined
+#endif
+
+#define PAGE_MASK		(~(PAGE_SIZE-1))
+
+#define LOG_BLOCK_SIZE          (12)
+#define EROFS_BLKSIZ            (1U << LOG_BLOCK_SIZE)
+
+#define EROFS_ISLOTBITS		5
+#define EROFS_SLOTSIZE		(1U << EROFS_ISLOTBITS)
+
+typedef u64 erofs_off_t;
+typedef u64 erofs_nid_t;
+/* data type for filesystem-wide blocks number */
+typedef u32 erofs_blk_t;
+
+#define NULL_ADDR	((unsigned int)-1)
+#define NULL_ADDR_UL	((unsigned long)-1)
+
+#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)
+
+#define BLK_ROUND_UP(addr)	DIV_ROUND_UP(addr, EROFS_BLKSIZ)
+
+struct erofs_sb_info {
+	u64 blocks;
+
+	erofs_blk_t meta_blkaddr;
+	erofs_blk_t xattr_blkaddr;
+
+	u32 feature_compat;
+	u32 feature_incompat;
+	u64 build_time;
+	u32 build_time_nsec;
+
+	unsigned char islotbits;
+
+	/* 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];
+
+	u16 available_compr_algs;
+	u16 lz4_max_distance;
+};
+
+/* global sbi */
+extern struct erofs_sb_info erofs_sbi;
+
+static inline erofs_off_t iloc(erofs_nid_t nid)
+{
+	return blknr_to_addr(erofs_sbi.meta_blkaddr) +
+		(nid << erofs_sbi.islotbits);
+}
+
+#define EROFS_FEATURE_FUNCS(name, compat, feature) \
+static inline bool erofs_sb_has_##name(void) \
+{ \
+	return erofs_sbi.feature_##compat & EROFS_FEATURE_##feature; \
+}
+
+EROFS_FEATURE_FUNCS(lz4_0padding, incompat, INCOMPAT_LZ4_0PADDING)
+EROFS_FEATURE_FUNCS(compr_cfgs, incompat, INCOMPAT_COMPR_CFGS)
+EROFS_FEATURE_FUNCS(big_pcluster, incompat, INCOMPAT_BIG_PCLUSTER)
+EROFS_FEATURE_FUNCS(sb_chksum, compat, COMPAT_SB_CHKSUM)
+
+#define EROFS_I_EA_INITED	(1 << 0)
+#define EROFS_I_Z_INITED	(1 << 1)
+
+struct erofs_inode {
+	unsigned int flags;
+	umode_t i_mode;
+	erofs_off_t i_size;
+
+	u64 i_ino[2];
+	u32 i_uid;
+	u32 i_gid;
+	u64 i_ctime;
+	u32 i_ctime_nsec;
+	u32 i_nlink;
+
+	union {
+		u32 i_blkaddr;
+		u32 i_blocks;
+		u32 i_rdev;
+	} u;
+
+	unsigned char datalayout;
+	unsigned char inode_isize;
+	unsigned int xattr_isize;
+	unsigned int extent_isize;
+
+	erofs_nid_t nid;
+
+	struct {
+		uint16_t z_advise;
+		uint8_t  z_algorithmtype[2];
+		uint8_t  z_logical_clusterbits;
+	};
+};
+
+static inline bool is_inode_layout_compression(struct erofs_inode *inode)
+{
+	return erofs_inode_is_data_compressed(inode->datalayout);
+}
+
+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_bitrange(value, EROFS_I_VERSION_BIT,
+			      EROFS_I_VERSION_BITS);
+}
+
+static inline unsigned int erofs_inode_datalayout(unsigned int value)
+{
+	return erofs_bitrange(value, EROFS_I_DATALAYOUT_BIT,
+			      EROFS_I_DATALAYOUT_BITS);
+}
+
+#define IS_ROOT(x)	((x) == (x)->i_parent)
+
+static inline bool is_dot_dotdot(const char *name)
+{
+	if (name[0] != '.')
+		return false;
+
+	return name[1] == '\0' || (name[1] == '.' && name[2] == '\0');
+}
+
+enum {
+	BH_Meta,
+	BH_Mapped,
+	BH_Zipped,
+	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)
+/* 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 {
+	char mpage[EROFS_BLKSIZ];
+
+	erofs_off_t m_pa, m_la;
+	u64 m_plen, m_llen;
+
+	unsigned int m_flags;
+	erofs_blk_t index;
+};
+
+int erofs_blk_read(void *buf, erofs_blk_t start, u32 nblocks);
+int erofs_dev_read(void *buf, u64 offset, size_t len);
+
+int erofs_read_superblock(void);
+int erofs_read_inode_from_disk(struct erofs_inode *vi);
+int erofs_ilookup(const char *path, struct erofs_inode *vi);
+int erofs_pread(struct erofs_inode *inode, char *buf,
+		erofs_off_t count, erofs_off_t offset);
+int z_erofs_fill_inode(struct erofs_inode *vi);
+int z_erofs_map_blocks_iter(struct erofs_inode *vi,
+			    struct erofs_map_blocks *map);
+
+#define EFSCORRUPTED	EUCLEAN		/* Filesystem is corrupted */
+#endif
diff --git a/fs/erofs/namei.c b/fs/erofs/namei.c
new file mode 100644
index 0000000000..4c5d614483
--- /dev/null
+++ b/fs/erofs/namei.c
@@ -0,0 +1,238 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include "internal.h"
+
+int erofs_read_inode_from_disk(struct erofs_inode *vi)
+{
+	int ret, ifmt;
+	char buf[sizeof(struct erofs_inode_extended)];
+	struct erofs_inode_compact *dic;
+	struct erofs_inode_extended *die;
+	const erofs_off_t inode_loc = iloc(vi->nid);
+
+	ret = erofs_dev_read(buf, inode_loc, sizeof(*dic));
+	if (ret < 0)
+		return -EIO;
+
+	dic = (struct erofs_inode_compact *)buf;
+	ifmt = le16_to_cpu(dic->i_format);
+
+	vi->datalayout = erofs_inode_datalayout(ifmt);
+	if (vi->datalayout >= EROFS_INODE_DATALAYOUT_MAX) {
+		erofs_err("unsupported datalayout %u of nid %llu",
+			  vi->datalayout, vi->nid | 0ULL);
+		return -EOPNOTSUPP;
+	}
+	switch (erofs_inode_version(ifmt)) {
+	case EROFS_INODE_LAYOUT_EXTENDED:
+		vi->inode_isize = sizeof(struct erofs_inode_extended);
+
+		ret = erofs_dev_read(buf + sizeof(*dic), inode_loc + sizeof(*dic),
+			       sizeof(*die) - sizeof(*dic));
+		if (ret < 0)
+			return -EIO;
+
+		die = (struct erofs_inode_extended *)buf;
+		vi->xattr_isize = erofs_xattr_ibody_size(die->i_xattr_icount);
+		vi->i_mode = le16_to_cpu(die->i_mode);
+
+		switch (vi->i_mode & S_IFMT) {
+		case S_IFREG:
+		case S_IFDIR:
+		case S_IFLNK:
+			vi->u.i_blkaddr = le32_to_cpu(die->i_u.raw_blkaddr);
+			break;
+		case S_IFCHR:
+		case S_IFBLK:
+			vi->u.i_rdev = 0;
+			break;
+		case S_IFIFO:
+		case S_IFSOCK:
+			vi->u.i_rdev = 0;
+			break;
+		default:
+			goto bogusimode;
+		}
+
+		vi->i_uid = le32_to_cpu(die->i_uid);
+		vi->i_gid = le32_to_cpu(die->i_gid);
+		vi->i_nlink = le32_to_cpu(die->i_nlink);
+
+		vi->i_ctime = le64_to_cpu(die->i_ctime);
+		vi->i_ctime_nsec = le64_to_cpu(die->i_ctime_nsec);
+		vi->i_size = le64_to_cpu(die->i_size);
+		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);
+		vi->i_mode = le16_to_cpu(dic->i_mode);
+
+		switch (vi->i_mode & S_IFMT) {
+		case S_IFREG:
+		case S_IFDIR:
+		case S_IFLNK:
+			vi->u.i_blkaddr = le32_to_cpu(dic->i_u.raw_blkaddr);
+			break;
+		case S_IFCHR:
+		case S_IFBLK:
+			vi->u.i_rdev = 0;
+			break;
+		case S_IFIFO:
+		case S_IFSOCK:
+			vi->u.i_rdev = 0;
+			break;
+		default:
+			goto bogusimode;
+		}
+
+		vi->i_uid = le16_to_cpu(dic->i_uid);
+		vi->i_gid = le16_to_cpu(dic->i_gid);
+		vi->i_nlink = le16_to_cpu(dic->i_nlink);
+
+		vi->i_ctime = erofs_sbi.build_time;
+		vi->i_ctime_nsec = erofs_sbi.build_time_nsec;
+
+		vi->i_size = le32_to_cpu(dic->i_size);
+		break;
+	default:
+		erofs_err("unsupported on-disk inode version %u of nid %llu",
+			  erofs_inode_version(ifmt), vi->nid | 0ULL);
+		return -EOPNOTSUPP;
+	}
+
+	vi->flags = 0;
+	if (erofs_inode_is_data_compressed(vi->datalayout))
+		return -EOPNOTSUPP;
+	return 0;
+bogusimode:
+	erofs_err("bogus i_mode (%o) @ nid %llu", vi->i_mode, vi->nid | 0ULL);
+	return -EFSCORRUPTED;
+}
+
+struct erofs_dirent *find_target_dirent(erofs_nid_t pnid,
+					void *dentry_blk,
+					const char *name, unsigned int len,
+					unsigned int nameoff,
+					unsigned int maxsize)
+{
+	struct erofs_dirent *de = dentry_blk;
+	const struct erofs_dirent *end = dentry_blk + nameoff;
+
+	while (de < end) {
+		const char *de_name;
+		unsigned int de_namelen;
+
+		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 (nameoff + de_namelen > maxsize ||
+		    de_namelen > EROFS_NAME_LEN) {
+			erofs_err("bogus dirent @ nid %llu", pnid | 0ULL);
+			DBG_BUGON(1);
+			return ERR_PTR(-EFSCORRUPTED);
+		}
+
+		if (len == de_namelen && !memcmp(de_name, name, de_namelen))
+			return de;
+		++de;
+	}
+	return NULL;
+}
+
+struct nameidata {
+	erofs_nid_t	nid;
+	unsigned int	ftype;
+};
+
+int erofs_namei(struct nameidata *nd,
+		const char *name, unsigned int len)
+{
+	erofs_nid_t nid = nd->nid;
+	int ret;
+	char buf[EROFS_BLKSIZ];
+	struct erofs_inode vi = { .nid = nid };
+	erofs_off_t offset;
+
+	ret = erofs_read_inode_from_disk(&vi);
+	if (ret)
+		return ret;
+
+	offset = 0;
+	while (offset < vi.i_size) {
+		erofs_off_t maxsize = min_t(erofs_off_t,
+					    vi.i_size - offset, EROFS_BLKSIZ);
+		struct erofs_dirent *de = (void *)buf;
+		unsigned int nameoff;
+
+		ret = erofs_pread(&vi, buf, maxsize, offset);
+		if (ret)
+			return ret;
+
+		nameoff = le16_to_cpu(de->nameoff);
+		if (nameoff < sizeof(struct erofs_dirent) ||
+		    nameoff >= PAGE_SIZE) {
+			erofs_err("invalid de[0].nameoff %u @ nid %llu",
+				  nameoff, nid | 0ULL);
+			return -EFSCORRUPTED;
+		}
+
+		de = find_target_dirent(nid, buf, name, len,
+					nameoff, maxsize);
+		if (IS_ERR(de))
+			return PTR_ERR(de);
+
+		if (de) {
+			nd->nid = le64_to_cpu(de->nid);
+			return 0;
+		}
+		offset += maxsize;
+	}
+	return -ENOENT;
+}
+
+static int link_path_walk(const char *name, struct nameidata *nd)
+{
+	nd->nid = erofs_sbi.root_nid;
+
+	while (*name == '/')
+		name++;
+
+	/* At this point we know we have a real path component. */
+	while (*name != '\0') {
+		const char *p = name;
+		int ret;
+
+		do {
+			++p;
+		} while (*p != '\0' && *p != '/');
+
+		DBG_BUGON(p <= name);
+		ret = erofs_namei(nd, name, p - name);
+		if (ret)
+			return ret;
+
+		name = p;
+		/* Skip until no more slashes. */
+		for (name = p; *name == '/'; ++name);
+	}
+	return 0;
+}
+
+int erofs_ilookup(const char *path, struct erofs_inode *vi)
+{
+	int ret;
+	struct nameidata nd;
+
+	ret = link_path_walk(path, &nd);
+	if (ret)
+		return ret;
+
+	vi->nid = nd.nid;
+	return erofs_read_inode_from_disk(vi);
+}
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
new file mode 100644
index 0000000000..c58a826b4b
--- /dev/null
+++ b/fs/erofs/super.c
@@ -0,0 +1,65 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include "internal.h"
+
+static bool check_layout_compatibility(struct erofs_sb_info *sbi,
+				       struct erofs_super_block *dsb)
+{
+	const unsigned int feature = le32_to_cpu(dsb->feature_incompat);
+
+	sbi->feature_incompat = feature;
+
+	/* check if current kernel meets all mandatory requirements */
+	if (feature & (~EROFS_ALL_FEATURE_INCOMPAT)) {
+		erofs_err("unidentified incompatible feature %x, please upgrade kernel version",
+			  feature & ~EROFS_ALL_FEATURE_INCOMPAT);
+		return false;
+	}
+	return true;
+}
+
+int erofs_read_superblock(void)
+{
+	char data[EROFS_BLKSIZ];
+	struct erofs_super_block *dsb;
+	unsigned int blkszbits;
+	int ret;
+
+	ret = erofs_blk_read(data, 0, 1);
+	if (ret < 0) {
+		erofs_err("cannot read erofs superblock: %d", ret);
+		return -EIO;
+	}
+	dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET);
+
+	ret = -EINVAL;
+	if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) {
+		erofs_err("cannot find valid erofs superblock");
+		return ret;
+	}
+
+	erofs_sbi.feature_compat = le32_to_cpu(dsb->feature_compat);
+
+	blkszbits = dsb->blkszbits;
+	/* 9(512 bytes) + LOG_SECTORS_PER_BLOCK == LOG_BLOCK_SIZE */
+	if (blkszbits != LOG_BLOCK_SIZE) {
+		erofs_err("blksize %u isn't supported on this platform",
+			  1 << blkszbits);
+		return ret;
+	}
+
+	if (!check_layout_compatibility(&erofs_sbi, dsb))
+		return ret;
+
+	erofs_sbi.blocks = le32_to_cpu(dsb->blocks);
+	erofs_sbi.meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr);
+	erofs_sbi.xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr);
+	erofs_sbi.islotbits = EROFS_ISLOTBITS;
+	erofs_sbi.root_nid = le16_to_cpu(dsb->root_nid);
+	erofs_sbi.inos = le64_to_cpu(dsb->inos);
+
+	erofs_sbi.build_time = le64_to_cpu(dsb->build_time);
+	erofs_sbi.build_time_nsec = le32_to_cpu(dsb->build_time_nsec);
+
+	memcpy(&erofs_sbi.uuid, dsb->uuid, sizeof(dsb->uuid));
+	return 0;
+}
diff --git a/fs/fs.c b/fs/fs.c
index 7c682582c8..3c06b0252b 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -26,6 +26,7 @@
 #include <linux/math64.h>
 #include <efi_loader.h>
 #include <squashfs.h>
+#include <erofs.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -304,6 +305,27 @@ static struct fstype_info fstypes[] = {
 		.unlink = fs_unlink_unsupported,
 		.mkdir = fs_mkdir_unsupported,
 	},
+#endif
+#if IS_ENABLED(CONFIG_FS_EROFS)
+	{
+		.fstype = FS_TYPE_EROFS,
+		.name = "erofs",
+		.null_dev_desc_ok = false,
+		.probe = erofs_probe,
+		.opendir = erofs_opendir,
+		.readdir = erofs_readdir,
+		.ls = fs_ls_generic,
+		.read = erofs_read,
+		.size = erofs_size,
+		.close = erofs_close,
+		.closedir = erofs_closedir,
+		.exists = erofs_exists,
+		.uuid = fs_uuid_unsupported,
+		.write = fs_write_unsupported,
+		.ln = fs_ln_unsupported,
+		.unlink = fs_unlink_unsupported,
+		.mkdir = fs_mkdir_unsupported,
+	},
 #endif
 	{
 		.fstype = FS_TYPE_ANY,
diff --git a/include/erofs.h b/include/erofs.h
new file mode 100644
index 0000000000..79de78257f
--- /dev/null
+++ b/include/erofs.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _EROFS_H_
+#define _EROFS_H_
+
+struct disk_partition;
+
+int erofs_opendir(const char *filename, struct fs_dir_stream **dirsp);
+int erofs_readdir(struct fs_dir_stream *dirs, struct fs_dirent **dentp);
+int erofs_probe(struct blk_desc *fs_dev_desc,
+	       struct disk_partition *fs_partition);
+int erofs_read(const char *filename, void *buf, loff_t offset,
+	      loff_t len, loff_t *actread);
+int erofs_size(const char *filename, loff_t *size);
+int erofs_exists(const char *filename);
+void erofs_close(void);
+void erofs_closedir(struct fs_dir_stream *dirs);
+int erofs_uuid(char *uuid_str);
+
+#endif /* _EROFS_H  */
diff --git a/include/fs.h b/include/fs.h
index 1c79e299fd..f96afc4c89 100644
--- a/include/fs.h
+++ b/include/fs.h
@@ -17,6 +17,7 @@ struct cmd_tbl;
 #define FS_TYPE_UBIFS	4
 #define FS_TYPE_BTRFS	5
 #define FS_TYPE_SQUASHFS 6
+#define FS_TYPE_EROFS   7
 
 struct blk_desc;
 
-- 
2.25.1


^ permalink raw reply	[flat|nested] 18+ messages in thread

* [PATCH 2/3] fs/erofs: add lz4 1.8.3 decompressor
  2021-08-22 15:48 [PATCH 1/3] fs/erofs: new filesystem Huang Jianan
@ 2021-08-22 15:48 ` Huang Jianan
  2021-08-22 15:48 ` [PATCH 3/3] fs/erofs: add lz4 decompression support Huang Jianan
                   ` (2 subsequent siblings)
  3 siblings, 0 replies; 18+ messages in thread
From: Huang Jianan @ 2021-08-22 15:48 UTC (permalink / raw)
  To: u-boot; +Cc: xiang, linux-erofs

From: Huang Jianan <huangjianan@oppo.com>

In order to use the newest LZ4_decompress_safe_partial() which can
now decode exactly the nb of bytes requested.

Signed-off-by: Huang Jianan <jnhuang95@gmail.com>
---
 fs/erofs/Makefile |   3 +-
 fs/erofs/lz4.c    | 534 ++++++++++++++++++++++++++++++++++++++++++++++
 fs/erofs/lz4.h    |   4 +
 3 files changed, 540 insertions(+), 1 deletion(-)
 create mode 100644 fs/erofs/lz4.c
 create mode 100644 fs/erofs/lz4.h

diff --git a/fs/erofs/Makefile b/fs/erofs/Makefile
index 7398ab7a36..c4fc5b794e 100644
--- a/fs/erofs/Makefile
+++ b/fs/erofs/Makefile
@@ -4,4 +4,5 @@
 obj-$(CONFIG_$(SPL_)FS_EROFS) = fs.o \
 				super.o \
 				namei.o \
-				data.o
+				data.o \
+				lz4.o
diff --git a/fs/erofs/lz4.c b/fs/erofs/lz4.c
new file mode 100644
index 0000000000..35f67c15eb
--- /dev/null
+++ b/fs/erofs/lz4.c
@@ -0,0 +1,534 @@
+// SPDX-License-Identifier: GPL 2.0+ OR BSD-2-Clause
+/*
+ * LZ4 - Fast LZ compression algorithm
+ * Copyright (C) 2011 - 2016, Yann Collet.
+ * BSD 2 - Clause License (http://www.opensource.org/licenses/bsd - license.php)
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *	* Redistributions of source code must retain the above copyright
+ *	  notice, this list of conditions and the following disclaimer.
+ *	* Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * You can contact the author at :
+ *	- LZ4 homepage : http://www.lz4.org
+ *	- LZ4 source repository : https://github.com/lz4/lz4
+ */
+#include <common.h>
+#include <compiler.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/bug.h>
+#include <asm/unaligned.h>
+
+#define FORCE_INLINE inline __attribute__((always_inline))
+
+static FORCE_INLINE u16 LZ4_readLE16(const void *src)
+{
+	return get_unaligned_le16(src);
+}
+
+static FORCE_INLINE void LZ4_copy8(void *dst, const void *src)
+{
+	put_unaligned(get_unaligned((const u64 *)src), (u64 *)dst);
+}
+
+typedef  uint8_t BYTE;
+typedef uint16_t U16;
+typedef uint32_t U32;
+typedef  int32_t S32;
+typedef uint64_t U64;
+typedef uintptr_t uptrval;
+
+static FORCE_INLINE void LZ4_write32(void *memPtr, U32 value)
+{
+	put_unaligned(value, (U32 *)memPtr);
+}
+
+/**************************************
+*  Reading and writing into memory
+**************************************/
+
+/* customized version of memcpy, which may overwrite up to 7 bytes beyond dstEnd */
+static void LZ4_wildCopy(void* dstPtr, const void* srcPtr, void* dstEnd)
+{
+    BYTE* d = (BYTE*)dstPtr;
+    const BYTE* s = (const BYTE*)srcPtr;
+    BYTE* e = (BYTE*)dstEnd;
+    do { LZ4_copy8(d,s); d+=8; s+=8; } while (d<e);
+}
+
+
+/**************************************
+*  Common Constants
+**************************************/
+#define MINMATCH 4
+
+#define WILDCOPYLENGTH 8
+#define LASTLITERALS 5
+#define MFLIMIT (WILDCOPYLENGTH + MINMATCH)
+
+/*
+ * ensure it's possible to write 2 x wildcopyLength
+ * without overflowing output buffer
+ */
+#define MATCH_SAFEGUARD_DISTANCE  ((2 * WILDCOPYLENGTH) - MINMATCH)
+
+#define KB (1 <<10)
+
+#define MAXD_LOG 16
+#define MAX_DISTANCE ((1 << MAXD_LOG) - 1)
+
+#define ML_BITS  4
+#define ML_MASK  ((1U<<ML_BITS)-1)
+#define RUN_BITS (8-ML_BITS)
+#define RUN_MASK ((1U<<RUN_BITS)-1)
+
+#define LZ4_STATIC_ASSERT(c)	BUILD_BUG_ON(!(c))
+
+/**************************************
+*  Local Structures and types
+**************************************/
+typedef enum { noDict = 0, withPrefix64k, usingExtDict } dict_directive;
+typedef enum { endOnOutputSize = 0, endOnInputSize = 1 } endCondition_directive;
+typedef enum { decode_full_block = 0, partial_decode = 1 } earlyEnd_directive;
+
+#define DEBUGLOG(l, ...) {}	/* disabled */
+
+#ifndef assert
+#define assert(condition) ((void)0)
+#endif
+
+/*
+ * LZ4_decompress_generic() :
+ * This generic decompression function covers all use cases.
+ * It shall be instantiated several times, using different sets of directives.
+ * Note that it is important for performance that this function really get inlined,
+ * in order to remove useless branches during compilation optimization.
+ */
+static FORCE_INLINE int LZ4_decompress_generic(
+	 const char * const src,
+	 char * const dst,
+	 int srcSize,
+		/*
+		 * If endOnInput == endOnInputSize,
+		 * this value is `dstCapacity`
+		 */
+	 int outputSize,
+	 /* endOnOutputSize, endOnInputSize */
+	 endCondition_directive endOnInput,
+	 /* full, partial */
+	 earlyEnd_directive partialDecoding,
+	 /* noDict, withPrefix64k, usingExtDict */
+	 dict_directive dict,
+	 /* always <= dst, == dst when no prefix */
+	 const BYTE * const lowPrefix,
+	 /* only if dict == usingExtDict */
+	 const BYTE * const dictStart,
+	 /* note : = 0 if noDict */
+	 const size_t dictSize
+	 )
+{
+	const BYTE *ip = (const BYTE *) src;
+	const BYTE * const iend = ip + srcSize;
+
+	BYTE *op = (BYTE *) dst;
+	BYTE * const oend = op + outputSize;
+	BYTE *cpy;
+
+	const BYTE * const dictEnd = (const BYTE *)dictStart + dictSize;
+	static const unsigned int inc32table[8] = {0, 1, 2, 1, 0, 4, 4, 4};
+	static const int dec64table[8] = {0, 0, 0, -1, -4, 1, 2, 3};
+
+	const int safeDecode = (endOnInput == endOnInputSize);
+	const int checkOffset = ((safeDecode) && (dictSize < (int)(64 * KB)));
+
+	/* Set up the "end" pointers for the shortcut. */
+	const BYTE *const shortiend = iend -
+		(endOnInput ? 14 : 8) /*maxLL*/ - 2 /*offset*/;
+	const BYTE *const shortoend = oend -
+		(endOnInput ? 14 : 8) /*maxLL*/ - 18 /*maxML*/;
+
+	DEBUGLOG(5, "%s (srcSize:%i, dstSize:%i)", __func__,
+		 srcSize, outputSize);
+
+	/* Special cases */
+	assert(lowPrefix <= op);
+	assert(src != NULL);
+
+	/* Empty output buffer */
+	if ((endOnInput) && (unlikely(outputSize == 0)))
+		return ((srcSize == 1) && (*ip == 0)) ? 0 : -1;
+
+	if ((!endOnInput) && (unlikely(outputSize == 0)))
+		return (*ip == 0 ? 1 : -1);
+
+	if ((endOnInput) && unlikely(srcSize == 0))
+		return -1;
+
+	/* Main Loop : decode sequences */
+	while (1) {
+		size_t length;
+		const BYTE *match;
+		size_t offset;
+
+		/* get literal length */
+		unsigned int const token = *ip++;
+		length = token>>ML_BITS;
+
+		/* ip < iend before the increment */
+		assert(!endOnInput || ip <= iend);
+
+		/*
+		 * A two-stage shortcut for the most common case:
+		 * 1) If the literal length is 0..14, and there is enough
+		 * space, enter the shortcut and copy 16 bytes on behalf
+		 * of the literals (in the fast mode, only 8 bytes can be
+		 * safely copied this way).
+		 * 2) Further if the match length is 4..18, copy 18 bytes
+		 * in a similar manner; but we ensure that there's enough
+		 * space in the output for those 18 bytes earlier, upon
+		 * entering the shortcut (in other words, there is a
+		 * combined check for both stages).
+		 *
+		 * The & in the likely() below is intentionally not && so that
+		 * some compilers can produce better parallelized runtime code
+		 */
+		if ((endOnInput ? length != RUN_MASK : length <= 8)
+		   /*
+		    * strictly "less than" on input, to re-enter
+		    * the loop with at least one byte
+		    */
+		   && likely((endOnInput ? ip < shortiend : 1) &
+			     (op <= shortoend))) {
+			/* Copy the literals */
+			memcpy(op, ip, endOnInput ? 16 : 8);
+			op += length; ip += length;
+
+			/*
+			 * The second stage:
+			 * prepare for match copying, decode full info.
+			 * If it doesn't work out, the info won't be wasted.
+			 */
+			length = token & ML_MASK; /* match length */
+			offset = LZ4_readLE16(ip);
+			ip += 2;
+			match = op - offset;
+			assert(match <= op); /* check overflow */
+
+			/* Do not deal with overlapping matches. */
+			if ((length != ML_MASK) &&
+			    (offset >= 8) &&
+			    (dict == withPrefix64k || match >= lowPrefix)) {
+				/* Copy the match. */
+				memcpy(op + 0, match + 0, 8);
+				memcpy(op + 8, match + 8, 8);
+				memcpy(op + 16, match + 16, 2);
+				op += length + MINMATCH;
+				/* Both stages worked, load the next token. */
+				continue;
+			}
+
+			/*
+			 * The second stage didn't work out, but the info
+			 * is ready. Propel it right to the point of match
+			 * copying.
+			 */
+			goto _copy_match;
+		}
+
+		/* decode literal length */
+		if (length == RUN_MASK) {
+			unsigned int s;
+
+			if (unlikely(endOnInput ? ip >= iend - RUN_MASK : 0)) {
+				/* overflow detection */
+				goto _output_error;
+			}
+			do {
+				s = *ip++;
+				length += s;
+			} while (likely(endOnInput
+				? ip < iend - RUN_MASK
+				: 1) & (s == 255));
+
+			if ((safeDecode)
+			    && unlikely((uptrval)(op) +
+					length < (uptrval)(op))) {
+				/* overflow detection */
+				goto _output_error;
+			}
+			if ((safeDecode)
+			    && unlikely((uptrval)(ip) +
+					length < (uptrval)(ip))) {
+				/* overflow detection */
+				goto _output_error;
+			}
+		}
+
+		/* copy literals */
+		cpy = op + length;
+		LZ4_STATIC_ASSERT(MFLIMIT >= WILDCOPYLENGTH);
+
+		if (((endOnInput) && ((cpy > oend - MFLIMIT)
+			|| (ip + length > iend - (2 + 1 + LASTLITERALS))))
+			|| ((!endOnInput) && (cpy > oend - WILDCOPYLENGTH))) {
+			if (partialDecoding) {
+				if (cpy > oend) {
+					/*
+					 * Partial decoding :
+					 * stop in the middle of literal segment
+					 */
+					cpy = oend;
+					length = oend - op;
+				}
+				if ((endOnInput)
+					&& (ip + length > iend)) {
+					/*
+					 * Error :
+					 * read attempt beyond
+					 * end of input buffer
+					 */
+					goto _output_error;
+				}
+			} else {
+				if ((!endOnInput)
+					&& (cpy != oend)) {
+					/*
+					 * Error :
+					 * block decoding must
+					 * stop exactly there
+					 */
+					goto _output_error;
+				}
+				if ((endOnInput)
+					&& ((ip + length != iend)
+					|| (cpy > oend))) {
+					/*
+					 * Error :
+					 * input must be consumed
+					 */
+					goto _output_error;
+				}
+			}
+
+			/*
+			 * supports overlapping memory regions; only matters
+			 * for in-place decompression scenarios
+			 */
+			memmove(op, ip, length);
+			ip += length;
+			op += length;
+
+			/* Necessarily EOF, due to parsing restrictions */
+			if (!partialDecoding || (cpy == oend))
+				break;
+		} else {
+			/* may overwrite up to WILDCOPYLENGTH beyond cpy */
+			LZ4_wildCopy(op, ip, cpy);
+			ip += length;
+			op = cpy;
+		}
+
+		/* get offset */
+		offset = LZ4_readLE16(ip);
+		ip += 2;
+		match = op - offset;
+
+		/* get matchlength */
+		length = token & ML_MASK;
+
+_copy_match:
+		if ((checkOffset) && (unlikely(match + dictSize < lowPrefix))) {
+			/* Error : offset outside buffers */
+			goto _output_error;
+		}
+
+		/* costs ~1%; silence an msan warning when offset == 0 */
+		/*
+		 * note : when partialDecoding, there is no guarantee that
+		 * at least 4 bytes remain available in output buffer
+		 */
+		if (!partialDecoding) {
+			assert(oend > op);
+			assert(oend - op >= 4);
+
+			LZ4_write32(op, (U32)offset);
+		}
+
+		if (length == ML_MASK) {
+			unsigned int s;
+
+			do {
+				s = *ip++;
+
+				if ((endOnInput) && (ip > iend - LASTLITERALS))
+					goto _output_error;
+
+				length += s;
+			} while (s == 255);
+
+			if ((safeDecode)
+				&& unlikely(
+					(uptrval)(op) + length < (uptrval)op)) {
+				/* overflow detection */
+				goto _output_error;
+			}
+		}
+
+		length += MINMATCH;
+
+		/* match starting within external dictionary */
+		if ((dict == usingExtDict) && (match < lowPrefix)) {
+			if (unlikely(op + length > oend - LASTLITERALS)) {
+				/* doesn't respect parsing restriction */
+				if (!partialDecoding)
+					goto _output_error;
+				length = min(length, (size_t)(oend - op));
+			}
+
+			if (length <= (size_t)(lowPrefix - match)) {
+				/*
+				 * match fits entirely within external
+				 * dictionary : just copy
+				 */
+				memmove(op, dictEnd - (lowPrefix - match),
+					length);
+				op += length;
+			} else {
+				/*
+				 * match stretches into both external
+				 * dictionary and current block
+				 */
+				size_t const copySize = (size_t)(lowPrefix - match);
+				size_t const restSize = length - copySize;
+
+				memcpy(op, dictEnd - copySize, copySize);
+				op += copySize;
+				if (restSize > (size_t)(op - lowPrefix)) {
+					/* overlap copy */
+					BYTE * const endOfMatch = op + restSize;
+					const BYTE *copyFrom = lowPrefix;
+
+					while (op < endOfMatch)
+						*op++ = *copyFrom++;
+				} else {
+					memcpy(op, lowPrefix, restSize);
+					op += restSize;
+				}
+			}
+			continue;
+		}
+
+		/* copy match within block */
+		cpy = op + length;
+
+		/*
+		 * partialDecoding :
+		 * may not respect endBlock parsing restrictions
+		 */
+		assert(op <= oend);
+		if (partialDecoding &&
+		    (cpy > oend - MATCH_SAFEGUARD_DISTANCE)) {
+			size_t const mlen = min(length, (size_t)(oend - op));
+			const BYTE * const matchEnd = match + mlen;
+			BYTE * const copyEnd = op + mlen;
+
+			if (matchEnd > op) {
+				/* overlap copy */
+				while (op < copyEnd)
+					*op++ = *match++;
+			} else {
+				memcpy(op, match, mlen);
+			}
+			op = copyEnd;
+			if (op == oend)
+				break;
+			continue;
+		}
+
+		if (unlikely(offset < 8)) {
+			op[0] = match[0];
+			op[1] = match[1];
+			op[2] = match[2];
+			op[3] = match[3];
+			match += inc32table[offset];
+			memcpy(op + 4, match, 4);
+			match -= dec64table[offset];
+		} else {
+			LZ4_copy8(op, match);
+			match += 8;
+		}
+
+		op += 8;
+
+		if (unlikely(cpy > oend - MATCH_SAFEGUARD_DISTANCE)) {
+			BYTE * const oCopyLimit = oend - (WILDCOPYLENGTH - 1);
+
+			if (cpy > oend - LASTLITERALS) {
+				/*
+				 * Error : last LASTLITERALS bytes
+				 * must be literals (uncompressed)
+				 */
+				goto _output_error;
+			}
+
+			if (op < oCopyLimit) {
+				LZ4_wildCopy(op, match, oCopyLimit);
+				match += oCopyLimit - op;
+				op = oCopyLimit;
+			}
+			while (op < cpy)
+				*op++ = *match++;
+		} else {
+			LZ4_copy8(op, match);
+			if (length > 16)
+				LZ4_wildCopy(op + 8, match + 8, cpy);
+		}
+		op = cpy; /* wildcopy correction */
+	}
+
+	/* end of decoding */
+	if (endOnInput) {
+		/* Nb of output bytes decoded */
+		return (int) (((char *)op) - dst);
+	} else {
+		/* Nb of input bytes read */
+		return (int) (((const char *)ip) - src);
+	}
+
+	/* Overflow error detected */
+_output_error:
+	return (int) (-(((const char *)ip) - src)) - 1;
+}
+
+int LZ4_decompress_safe(const char *source, char *dest,
+	int compressedSize, int maxDecompressedSize)
+{
+	return LZ4_decompress_generic(source, dest,
+				      compressedSize, maxDecompressedSize,
+				      endOnInputSize, decode_full_block,
+				      noDict, (BYTE *)dest, NULL, 0);
+}
+
+int LZ4_decompress_safe_partial(const char *src, char *dst,
+	int compressedSize, int targetOutputSize, int dstCapacity)
+{
+	dstCapacity = min(targetOutputSize, dstCapacity);
+	return LZ4_decompress_generic(src, dst, compressedSize, dstCapacity,
+				      endOnInputSize, partial_decode,
+				      noDict, (BYTE *)dst, NULL, 0);
+}
diff --git a/fs/erofs/lz4.h b/fs/erofs/lz4.h
new file mode 100644
index 0000000000..0b4bdf4fbe
--- /dev/null
+++ b/fs/erofs/lz4.h
@@ -0,0 +1,4 @@
+int LZ4_decompress_safe(const char *source, char *dest,
+	int compressedSize, int maxDecompressedSize);
+int LZ4_decompress_safe_partial(const char *src, char *dst,
+	int compressedSize, int targetOutputSize, int dstCapacity);
-- 
2.25.1


^ permalink raw reply	[flat|nested] 18+ messages in thread

* [PATCH 3/3] fs/erofs: add lz4 decompression support
  2021-08-22 15:48 [PATCH 1/3] fs/erofs: new filesystem Huang Jianan
  2021-08-22 15:48 ` [PATCH 2/3] fs/erofs: add lz4 1.8.3 decompressor Huang Jianan
@ 2021-08-22 15:48 ` Huang Jianan
  2021-08-23  4:24 ` [PATCH 1/3] fs/erofs: new filesystem Bin Meng
  2021-08-23 12:36 ` [PATCH v2 0/3] " Huang Jianan
  3 siblings, 0 replies; 18+ messages in thread
From: Huang Jianan @ 2021-08-22 15:48 UTC (permalink / raw)
  To: u-boot; +Cc: xiang, linux-erofs

From: Huang Jianan <huangjianan@oppo.com>

Support EROFS lz4 compressed files.

Signed-off-by: Huang Jianan <jnhuang95@gmail.com>
---
 fs/erofs/Makefile     |   4 +-
 fs/erofs/data.c       |  84 ++++++-
 fs/erofs/decompress.c |  74 ++++++
 fs/erofs/decompress.h |  29 +++
 fs/erofs/namei.c      |   2 +-
 fs/erofs/zmap.c       | 517 ++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 707 insertions(+), 3 deletions(-)
 create mode 100644 fs/erofs/decompress.c
 create mode 100644 fs/erofs/decompress.h
 create mode 100644 fs/erofs/zmap.c

diff --git a/fs/erofs/Makefile b/fs/erofs/Makefile
index c4fc5b794e..8f1f99a096 100644
--- a/fs/erofs/Makefile
+++ b/fs/erofs/Makefile
@@ -5,4 +5,6 @@ obj-$(CONFIG_$(SPL_)FS_EROFS) = fs.o \
 				super.o \
 				namei.o \
 				data.o \
-				lz4.o
+				lz4.o \
+				decompress.o \
+				zmap.o
diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index a0f613264a..04ba9b5765 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0+
 #include "internal.h"
+#include "decompress.h"
 
 static int erofs_map_blocks_flatmode(struct erofs_inode *inode,
 				     struct erofs_map_blocks *map,
@@ -107,6 +108,87 @@ static int erofs_read_raw_data(struct erofs_inode *inode, char *buffer,
 	return 0;
 }
 
+static int z_erofs_read_data(struct erofs_inode *inode, char *buffer,
+			     erofs_off_t size, erofs_off_t offset)
+{
+	erofs_off_t end, length, skip;
+	struct erofs_map_blocks map = {
+		.index = UINT_MAX,
+	};
+	bool partial;
+	unsigned int algorithmformat, bufsize;
+	char *raw = NULL;
+	int ret = 0;
+
+	end = offset + size;
+	bufsize = 0;
+	while (end > offset) {
+		map.m_la = end - 1;
+
+		ret = z_erofs_map_blocks_iter(inode, &map);
+		if (ret)
+			break;
+
+		/*
+		 * trim to the needed size if the returned extent is quite
+		 * larger than requested, and set up partial flag as well.
+		 */
+		if (end < map.m_la + map.m_llen) {
+			length = end - map.m_la;
+			partial = true;
+		} else {
+			DBG_BUGON(end != map.m_la + map.m_llen);
+			length = map.m_llen;
+			partial = !(map.m_flags & EROFS_MAP_FULL_MAPPED);
+		}
+
+		if (map.m_la < offset) {
+			skip = offset - map.m_la;
+			end = offset;
+		} else {
+			skip = 0;
+			end = map.m_la;
+		}
+
+		if (!(map.m_flags & EROFS_MAP_MAPPED)) {
+			memset(buffer + end - offset, 0, length);
+			end = map.m_la;
+			continue;
+		}
+
+		if (map.m_plen > bufsize) {
+			bufsize = map.m_plen;
+			raw = realloc(raw, bufsize);
+			if (!raw) {
+				ret = -ENOMEM;
+				break;
+			}
+		}
+		ret = erofs_dev_read(raw, map.m_pa, map.m_plen);
+		if (ret < 0)
+			break;
+
+		algorithmformat = map.m_flags & EROFS_MAP_ZIPPED ?
+						Z_EROFS_COMPRESSION_LZ4 :
+						Z_EROFS_COMPRESSION_SHIFTED;
+
+		ret = z_erofs_decompress(&(struct z_erofs_decompress_req) {
+					.in = raw,
+					.out = buffer + end - offset,
+					.decodedskip = skip,
+					.inputsize = map.m_plen,
+					.decodedlength = length,
+					.alg = algorithmformat,
+					.partial_decoding = partial
+					 });
+		if (ret < 0)
+			break;
+	}
+	if (raw)
+		free(raw);
+	return ret < 0 ? ret : 0;
+}
+
 int erofs_pread(struct erofs_inode *inode, char *buf,
 		erofs_off_t count, erofs_off_t offset)
 {
@@ -116,7 +198,7 @@ int erofs_pread(struct erofs_inode *inode, char *buf,
 		return erofs_read_raw_data(inode, buf, count, offset);
 	case EROFS_INODE_FLAT_COMPRESSION_LEGACY:
 	case EROFS_INODE_FLAT_COMPRESSION:
-		return -EOPNOTSUPP;
+		return z_erofs_read_data(inode, buf, count, offset);
 	default:
 		break;
 	}
diff --git a/fs/erofs/decompress.c b/fs/erofs/decompress.c
new file mode 100644
index 0000000000..f960f6442a
--- /dev/null
+++ b/fs/erofs/decompress.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include "decompress.h"
+#include "lz4.h"
+
+static int z_erofs_decompress_lz4(struct z_erofs_decompress_req *rq)
+{
+	int ret = 0;
+	char *dest = rq->out;
+	char *src = rq->in;
+	char *buff = NULL;
+	bool support_0padding = false;
+	unsigned int inputmargin = 0;
+
+	if (erofs_sb_has_lz4_0padding()) {
+		support_0padding = true;
+
+		while (!src[inputmargin & ~PAGE_MASK])
+			if (!(++inputmargin & ~PAGE_MASK))
+				break;
+
+		if (inputmargin >= rq->inputsize)
+			return -EIO;
+	}
+
+	if (rq->decodedskip) {
+		buff = malloc(rq->decodedlength);
+		if (!buff)
+			return -ENOMEM;
+		dest = buff;
+	}
+
+	if (rq->partial_decoding || !support_0padding)
+		ret = LZ4_decompress_safe_partial(src + inputmargin, dest,
+				rq->inputsize - inputmargin,
+				rq->decodedlength, rq->decodedlength);
+	else
+		ret = LZ4_decompress_safe(src + inputmargin, dest,
+					  rq->inputsize - inputmargin,
+					  rq->decodedlength);
+
+	if (ret != (int)rq->decodedlength) {
+		ret = -EIO;
+		goto out;
+	}
+
+	if (rq->decodedskip)
+		memcpy(rq->out, dest + rq->decodedskip,
+		       rq->decodedlength - rq->decodedskip);
+
+out:
+	if (buff)
+		free(buff);
+
+	return ret;
+}
+
+int z_erofs_decompress(struct z_erofs_decompress_req *rq)
+{
+	if (rq->alg == Z_EROFS_COMPRESSION_SHIFTED) {
+		if (rq->inputsize != EROFS_BLKSIZ)
+			return -EFSCORRUPTED;
+
+		DBG_BUGON(rq->decodedlength > EROFS_BLKSIZ);
+		DBG_BUGON(rq->decodedlength < rq->decodedskip);
+
+		memcpy(rq->out, rq->in + rq->decodedskip,
+		       rq->decodedlength - rq->decodedskip);
+		return 0;
+	}
+
+	if (rq->alg == Z_EROFS_COMPRESSION_LZ4)
+		return z_erofs_decompress_lz4(rq);
+	return -EOPNOTSUPP;
+}
diff --git a/fs/erofs/decompress.h b/fs/erofs/decompress.h
new file mode 100644
index 0000000000..a12e11f386
--- /dev/null
+++ b/fs/erofs/decompress.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+#ifndef __EROFS_DECOMPRESS_H
+#define __EROFS_DECOMPRESS_H
+
+#include "internal.h"
+
+enum {
+	Z_EROFS_COMPRESSION_SHIFTED = Z_EROFS_COMPRESSION_MAX,
+	Z_EROFS_COMPRESSION_RUNTIME_MAX
+};
+
+struct z_erofs_decompress_req {
+	char *in, *out;
+
+	/*
+	 * initial decompressed bytes that need to be skipped
+	 * when finally copying to output buffer
+	 */
+	unsigned int decodedskip;
+	unsigned int inputsize, decodedlength;
+
+	/* indicate the algorithm will be used for decompression */
+	unsigned int alg;
+	bool partial_decoding;
+};
+
+int z_erofs_decompress(struct z_erofs_decompress_req *rq);
+
+#endif
diff --git a/fs/erofs/namei.c b/fs/erofs/namei.c
index 4c5d614483..7a0fbe2bc1 100644
--- a/fs/erofs/namei.c
+++ b/fs/erofs/namei.c
@@ -101,7 +101,7 @@ int erofs_read_inode_from_disk(struct erofs_inode *vi)
 
 	vi->flags = 0;
 	if (erofs_inode_is_data_compressed(vi->datalayout))
-		return -EOPNOTSUPP;
+		z_erofs_fill_inode(vi);
 	return 0;
 bogusimode:
 	erofs_err("bogus i_mode (%o) @ nid %llu", vi->i_mode, vi->nid | 0ULL);
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
new file mode 100644
index 0000000000..ff7f89f40c
--- /dev/null
+++ b/fs/erofs/zmap.c
@@ -0,0 +1,517 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include "internal.h"
+
+int z_erofs_fill_inode(struct erofs_inode *vi)
+{
+	if (!erofs_sb_has_big_pcluster() &&
+	    vi->datalayout == 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->flags |= EROFS_I_Z_INITED;
+	}
+	return 0;
+}
+
+static int z_erofs_fill_inode_lazy(struct erofs_inode *vi)
+{
+	int ret;
+	erofs_off_t pos;
+	struct z_erofs_map_header *h;
+	char buf[sizeof(struct z_erofs_map_header)];
+
+	if (vi->flags & EROFS_I_Z_INITED)
+		return 0;
+
+	DBG_BUGON(!erofs_sb_has_big_pcluster() &&
+		  vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY);
+	pos = round_up(iloc(vi->nid) + vi->inode_isize + vi->xattr_isize, 8);
+
+	ret = erofs_dev_read(buf, pos, sizeof(buf));
+	if (ret < 0)
+		return -EIO;
+
+	h = (struct z_erofs_map_header *)buf;
+	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) {
+		erofs_err("unknown compression format %u for nid %llu",
+			  vi->z_algorithmtype[0], (unsigned long long)vi->nid);
+		return -EOPNOTSUPP;
+	}
+
+	vi->z_logical_clusterbits = LOG_BLOCK_SIZE + (h->h_clusterbits & 7);
+	if (vi->datalayout == EROFS_INODE_FLAT_COMPRESSION &&
+	    !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1) ^
+	    !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_2)) {
+		erofs_err(
+"big pcluster head1/2 of compact indexes should be consistent for nid %llu",
+			  vi->nid * 1ULL);
+		return -EFSCORRUPTED;
+	}
+	vi->flags |= EROFS_I_Z_INITED;
+	return 0;
+}
+
+struct z_erofs_maprecorder {
+	struct erofs_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, compressedlcs;
+};
+
+static int z_erofs_reload_indexes(struct z_erofs_maprecorder *m,
+				  erofs_blk_t eblk)
+{
+	int ret;
+	struct erofs_map_blocks *const map = m->map;
+	char *mpage = map->mpage;
+
+	if (map->index == eblk)
+		return 0;
+
+	ret = erofs_blk_read(mpage, eblk, 1);
+	if (ret < 0)
+		return -EIO;
+
+	map->index = eblk;
+
+	return 0;
+}
+
+static int legacy_load_cluster_from_disk(struct z_erofs_maprecorder *m,
+					 unsigned long lcn)
+{
+	struct erofs_inode *const vi = m->inode;
+	const erofs_off_t ibase = iloc(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]);
+		if (m->delta[0] & Z_EROFS_VLE_DI_D0_CBLKCNT) {
+			if (!(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1)) {
+				DBG_BUGON(1);
+				return -EFSCORRUPTED;
+			}
+			m->compressedlcs = m->delta[0] &
+				~Z_EROFS_VLE_DI_D0_CBLKCNT;
+			m->delta[0] = 1;
+		}
+		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 -EOPNOTSUPP;
+	}
+	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_inode *const vi = 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;
+	bool big_pcluster;
+
+	if (1 << amortizedshift == 4)
+		vcnt = 2;
+	else if (1 << amortizedshift == 2 && lclusterbits == 12)
+		vcnt = 16;
+	else
+		return -EOPNOTSUPP;
+
+	big_pcluster = vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1;
+	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 (lo & Z_EROFS_VLE_DI_D0_CBLKCNT) {
+			if (!big_pcluster) {
+				DBG_BUGON(1);
+				return -EFSCORRUPTED;
+			}
+			m->compressedlcs = lo & ~Z_EROFS_VLE_DI_D0_CBLKCNT;
+			m->delta[0] = 1;
+			return 0;
+		} else if (i + 1 != (int)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;
+		else if (lo & Z_EROFS_VLE_DI_D0_CBLKCNT)
+			lo = 1;
+		m->delta[0] = lo + 1;
+		return 0;
+	}
+	m->clusterofs = lo;
+	m->delta[0] = 0;
+	/* figout out blkaddr (pblk) for HEAD lclusters */
+	if (!big_pcluster) {
+		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;
+		}
+	} else {
+		nblk = 0;
+		while (i > 0) {
+			--i;
+			lo = decode_compactedbits(lclusterbits, lomask,
+						  in, encodebits * i, &type);
+			if (type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD) {
+				if (lo & Z_EROFS_VLE_DI_D0_CBLKCNT) {
+					--i;
+					nblk += lo & ~Z_EROFS_VLE_DI_D0_CBLKCNT;
+					continue;
+				}
+				if (lo == 1) {
+					DBG_BUGON(1);
+					/* --i; ++nblk;	continue; */
+					return -EFSCORRUPTED;
+				}
+				i -= lo - 2;
+				continue;
+			}
+			++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 erofs_inode *const vi = m->inode;
+	const unsigned int lclusterbits = vi->z_logical_clusterbits;
+	const erofs_off_t ebase = round_up(iloc(vi->nid) + vi->inode_isize +
+					   vi->xattr_isize, 8) +
+		sizeof(struct z_erofs_map_header);
+	const unsigned int totalidx = DIV_ROUND_UP(vi->i_size, EROFS_BLKSIZ);
+	unsigned int compacted_4b_initial, compacted_2b;
+	unsigned int amortizedshift;
+	erofs_off_t pos;
+	int err;
+
+	if (lclusterbits != 12)
+		return -EOPNOTSUPP;
+
+	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 z_erofs_load_cluster_from_disk(struct z_erofs_maprecorder *m,
+					  unsigned int lcn)
+{
+	const unsigned int datamode = m->inode->datalayout;
+
+	if (datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY)
+		return 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 z_erofs_extent_lookback(struct z_erofs_maprecorder *m,
+				   unsigned int lookback_distance)
+{
+	struct erofs_inode *const vi = 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) {
+		erofs_err("bogus lookback distance @ nid %llu",
+			  (unsigned long long)vi->nid);
+		DBG_BUGON(1);
+		return -EFSCORRUPTED;
+	}
+
+	/* load extent head logical cluster if needed */
+	lcn -= lookback_distance;
+	err = z_erofs_load_cluster_from_disk(m, lcn);
+	if (err)
+		return err;
+
+	switch (m->type) {
+	case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
+		if (!m->delta[0]) {
+			erofs_err("invalid lookback distance 0 @ nid %llu",
+				  (unsigned long long)vi->nid);
+			DBG_BUGON(1);
+			return -EFSCORRUPTED;
+		}
+		return z_erofs_extent_lookback(m, m->delta[0]);
+	case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
+		map->m_flags &= ~EROFS_MAP_ZIPPED;
+	case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
+		map->m_la = (lcn << lclusterbits) | m->clusterofs;
+		break;
+	default:
+		erofs_err("unknown type %u @ lcn %lu of nid %llu",
+			  m->type, lcn, (unsigned long long)vi->nid);
+		DBG_BUGON(1);
+		return -EOPNOTSUPP;
+	}
+	return 0;
+}
+
+static int z_erofs_get_extent_compressedlen(struct z_erofs_maprecorder *m,
+					    unsigned int initial_lcn)
+{
+	struct erofs_inode *const vi = m->inode;
+	struct erofs_map_blocks *const map = m->map;
+	const unsigned int lclusterbits = vi->z_logical_clusterbits;
+	unsigned long lcn;
+	int err;
+
+	DBG_BUGON(m->type != Z_EROFS_VLE_CLUSTER_TYPE_PLAIN &&
+		  m->type != Z_EROFS_VLE_CLUSTER_TYPE_HEAD);
+	if (!(map->m_flags & EROFS_MAP_ZIPPED) ||
+	    !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1)) {
+		map->m_plen = 1 << lclusterbits;
+		return 0;
+	}
+
+	lcn = m->lcn + 1;
+	if (m->compressedlcs)
+		goto out;
+
+	err = z_erofs_load_cluster_from_disk(m, lcn);
+	if (err)
+		return err;
+
+	/*
+	 * If the 1st NONHEAD lcluster has already been handled initially w/o
+	 * valid compressedlcs, which means at least it mustn't be CBLKCNT, or
+	 * an internal implemenatation error is detected.
+	 *
+	 * The following code can also handle it properly anyway, but let's
+	 * BUG_ON in the debugging mode only for developers to notice that.
+	 */
+	DBG_BUGON(lcn == initial_lcn &&
+		  m->type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD);
+
+	switch (m->type) {
+	case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
+	case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
+		/*
+		 * if the 1st NONHEAD lcluster is actually PLAIN or HEAD type
+		 * rather than CBLKCNT, it's a 1 lcluster-sized pcluster.
+		 */
+		m->compressedlcs = 1;
+		break;
+	case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
+		if (m->delta[0] != 1)
+			goto err_bonus_cblkcnt;
+		if (m->compressedlcs)
+			break;
+		/* fallthrough */
+	default:
+		erofs_err("cannot found CBLKCNT @ lcn %lu of nid %llu",
+			  lcn, vi->nid | 0ULL);
+		DBG_BUGON(1);
+		return -EFSCORRUPTED;
+	}
+out:
+	map->m_plen = m->compressedlcs << lclusterbits;
+	return 0;
+err_bonus_cblkcnt:
+	erofs_err("bogus CBLKCNT @ lcn %lu of nid %llu",
+		  lcn, vi->nid | 0ULL);
+	DBG_BUGON(1);
+	return -EFSCORRUPTED;
+}
+
+int z_erofs_map_blocks_iter(struct erofs_inode *vi,
+			    struct erofs_map_blocks *map)
+{
+	struct z_erofs_maprecorder m = {
+		.inode = vi,
+		.map = map,
+		.kaddr = map->mpage,
+	};
+	int err = 0;
+	unsigned int lclusterbits, endoff;
+	unsigned long initial_lcn;
+	unsigned long long ofs, end;
+
+	/* when trying to read beyond EOF, leave it unmapped */
+	if (map->m_la >= vi->i_size) {
+		map->m_llen = map->m_la + 1 - vi->i_size;
+		map->m_la = vi->i_size;
+		map->m_flags = 0;
+		goto out;
+	}
+
+	err = z_erofs_fill_inode_lazy(vi);
+	if (err)
+		goto out;
+
+	lclusterbits = vi->z_logical_clusterbits;
+	ofs = map->m_la;
+	initial_lcn = ofs >> lclusterbits;
+	endoff = ofs & ((1 << lclusterbits) - 1);
+
+	err = z_erofs_load_cluster_from_disk(&m, initial_lcn);
+	if (err)
+		goto 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;
+	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 (!m.lcn) {
+			erofs_err("invalid logical cluster 0 at nid %llu",
+				  (unsigned long long)vi->nid);
+			err = -EFSCORRUPTED;
+			goto out;
+		}
+		end = (m.lcn << lclusterbits) | m.clusterofs;
+		map->m_flags |= EROFS_MAP_FULL_MAPPED;
+		m.delta[0] = 1;
+	case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
+		/* get the correspoinding first chunk */
+		err = z_erofs_extent_lookback(&m, m.delta[0]);
+		if (err)
+			goto out;
+		break;
+	default:
+		erofs_err("unknown type %u @ offset %llu of nid %llu",
+			  m.type, ofs, (unsigned long long)vi->nid);
+		err = -EOPNOTSUPP;
+		goto out;
+	}
+
+	map->m_llen = end - map->m_la;
+	map->m_pa = blknr_to_addr(m.pblk);
+
+	err = z_erofs_get_extent_compressedlen(&m, initial_lcn);
+	if (err)
+		goto out;
+	map->m_flags |= EROFS_MAP_MAPPED;
+
+out:
+	erofs_dbg("m_la %" PRIu64 " m_pa %" PRIu64 " m_llen %" PRIu64 " m_plen %" PRIu64 " m_flags 0%o",
+		  map->m_la, map->m_pa,
+		  map->m_llen, map->m_plen, map->m_flags);
+
+	DBG_BUGON(err < 0 && err != -ENOMEM);
+	return err;
+}
-- 
2.25.1


^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [PATCH 1/3] fs/erofs: new filesystem
  2021-08-22 15:48 [PATCH 1/3] fs/erofs: new filesystem Huang Jianan
  2021-08-22 15:48 ` [PATCH 2/3] fs/erofs: add lz4 1.8.3 decompressor Huang Jianan
  2021-08-22 15:48 ` [PATCH 3/3] fs/erofs: add lz4 decompression support Huang Jianan
@ 2021-08-23  4:24 ` Bin Meng
  2021-08-23 11:46   ` Huang Jianan
  2021-08-23 12:36 ` [PATCH v2 0/3] " Huang Jianan
  3 siblings, 1 reply; 18+ messages in thread
From: Bin Meng @ 2021-08-23  4:24 UTC (permalink / raw)
  To: Huang Jianan; +Cc: U-Boot Mailing List, xiang, linux-erofs

On Mon, Aug 23, 2021 at 12:03 AM Huang Jianan <jnhuang95@gmail.com> wrote:
>
> From: Huang Jianan <huangjianan@oppo.com>
>
> Add erofs filesystem support.
>
> The code is adapted from erofs-utils in order to reduce maintenance
> burden and keep with the latest feature.
>
> This patch mainly deals with uncompressed files.
>
> Signed-off-by: Huang Jianan <jnhuang95@gmail.com>

From and SoB should be the same person.

> ---
>  fs/Kconfig          |   1 +
>  fs/Makefile         |   1 +
>  fs/erofs/Kconfig    |  12 ++
>  fs/erofs/Makefile   |   7 +
>  fs/erofs/data.c     | 124 ++++++++++++++
>  fs/erofs/erofs_fs.h | 384 ++++++++++++++++++++++++++++++++++++++++++++
>  fs/erofs/fs.c       | 230 ++++++++++++++++++++++++++
>  fs/erofs/internal.h | 203 +++++++++++++++++++++++
>  fs/erofs/namei.c    | 238 +++++++++++++++++++++++++++
>  fs/erofs/super.c    |  65 ++++++++
>  fs/fs.c             |  22 +++
>  include/erofs.h     |  19 +++
>  include/fs.h        |   1 +
>  13 files changed, 1307 insertions(+)
>  create mode 100644 fs/erofs/Kconfig
>  create mode 100644 fs/erofs/Makefile
>  create mode 100644 fs/erofs/data.c
>  create mode 100644 fs/erofs/erofs_fs.h
>  create mode 100644 fs/erofs/fs.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 include/erofs.h
>

Regards,
Bin

^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [PATCH 1/3] fs/erofs: new filesystem
  2021-08-23  4:24 ` [PATCH 1/3] fs/erofs: new filesystem Bin Meng
@ 2021-08-23 11:46   ` Huang Jianan
  0 siblings, 0 replies; 18+ messages in thread
From: Huang Jianan @ 2021-08-23 11:46 UTC (permalink / raw)
  To: Bin Meng; +Cc: U-Boot Mailing List, xiang, linux-erofs



在 2021/8/23 12:24, Bin Meng 写道:
> On Mon, Aug 23, 2021 at 12:03 AM Huang Jianan <jnhuang95@gmail.com> wrote:
>> From: Huang Jianan <huangjianan@oppo.com>
>>
>> Add erofs filesystem support.
>>
>> The code is adapted from erofs-utils in order to reduce maintenance
>> burden and keep with the latest feature.
>>
>> This patch mainly deals with uncompressed files.
>>
>> Signed-off-by: Huang Jianan <jnhuang95@gmail.com>
>  From and SoB should be the same person.
Thanks for pointing this out,I will update soon.
>> ---
>>   fs/Kconfig          |   1 +
>>   fs/Makefile         |   1 +
>>   fs/erofs/Kconfig    |  12 ++
>>   fs/erofs/Makefile   |   7 +
>>   fs/erofs/data.c     | 124 ++++++++++++++
>>   fs/erofs/erofs_fs.h | 384 ++++++++++++++++++++++++++++++++++++++++++++
>>   fs/erofs/fs.c       | 230 ++++++++++++++++++++++++++
>>   fs/erofs/internal.h | 203 +++++++++++++++++++++++
>>   fs/erofs/namei.c    | 238 +++++++++++++++++++++++++++
>>   fs/erofs/super.c    |  65 ++++++++
>>   fs/fs.c             |  22 +++
>>   include/erofs.h     |  19 +++
>>   include/fs.h        |   1 +
>>   13 files changed, 1307 insertions(+)
>>   create mode 100644 fs/erofs/Kconfig
>>   create mode 100644 fs/erofs/Makefile
>>   create mode 100644 fs/erofs/data.c
>>   create mode 100644 fs/erofs/erofs_fs.h
>>   create mode 100644 fs/erofs/fs.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 include/erofs.h
>>
> Regards,
> Bin


^ permalink raw reply	[flat|nested] 18+ messages in thread

* [PATCH v2 0/3] fs/erofs: new filesystem
  2021-08-22 15:48 [PATCH 1/3] fs/erofs: new filesystem Huang Jianan
                   ` (2 preceding siblings ...)
  2021-08-23  4:24 ` [PATCH 1/3] fs/erofs: new filesystem Bin Meng
@ 2021-08-23 12:36 ` Huang Jianan
  2021-08-23 12:36   ` [PATCH v2 1/3] fs/erofs: add erofs filesystem support Huang Jianan
                     ` (4 more replies)
  3 siblings, 5 replies; 18+ messages in thread
From: Huang Jianan @ 2021-08-23 12:36 UTC (permalink / raw)
  To: u-boot; +Cc: xiang, linux-erofs

From: Huang Jianan <huangjianan@oppo.com>

Add erofs filesystem support.

The code is adapted from erofs-utils in order to reduce maintenance
burden and keep with the latest feature.

Changes since v1:
 - fix the inconsistency between From and SoB (Bin Meng);
 - add missing license header;

Huang Jianan (3):
  fs/erofs: add erofs filesystem support
  fs/erofs: add lz4 1.8.3 decompressor
  fs/erofs: add lz4 decompression support

 fs/Kconfig            |   1 +
 fs/Makefile           |   1 +
 fs/erofs/Kconfig      |  12 +
 fs/erofs/Makefile     |  10 +
 fs/erofs/data.c       | 206 ++++++++++++++++
 fs/erofs/decompress.c |  74 ++++++
 fs/erofs/decompress.h |  29 +++
 fs/erofs/erofs_fs.h   | 384 ++++++++++++++++++++++++++++++
 fs/erofs/fs.c         | 231 ++++++++++++++++++
 fs/erofs/internal.h   | 203 ++++++++++++++++
 fs/erofs/lz4.c        | 534 ++++++++++++++++++++++++++++++++++++++++++
 fs/erofs/lz4.h        |   5 +
 fs/erofs/namei.c      | 238 +++++++++++++++++++
 fs/erofs/super.c      |  65 +++++
 fs/erofs/zmap.c       | 517 ++++++++++++++++++++++++++++++++++++++++
 fs/fs.c               |  22 ++
 include/erofs.h       |  19 ++
 include/fs.h          |   1 +
 18 files changed, 2552 insertions(+)
 create mode 100644 fs/erofs/Kconfig
 create mode 100644 fs/erofs/Makefile
 create mode 100644 fs/erofs/data.c
 create mode 100644 fs/erofs/decompress.c
 create mode 100644 fs/erofs/decompress.h
 create mode 100644 fs/erofs/erofs_fs.h
 create mode 100644 fs/erofs/fs.c
 create mode 100644 fs/erofs/internal.h
 create mode 100644 fs/erofs/lz4.c
 create mode 100644 fs/erofs/lz4.h
 create mode 100644 fs/erofs/namei.c
 create mode 100644 fs/erofs/super.c
 create mode 100644 fs/erofs/zmap.c
 create mode 100644 include/erofs.h

-- 
2.25.1


^ permalink raw reply	[flat|nested] 18+ messages in thread

* [PATCH v2 1/3] fs/erofs: add erofs filesystem support
  2021-08-23 12:36 ` [PATCH v2 0/3] " Huang Jianan
@ 2021-08-23 12:36   ` Huang Jianan
  2021-08-25 22:39     ` Tom Rini
  2021-08-23 12:36   ` [PATCH v2 2/3] fs/erofs: add lz4 1.8.3 decompressor Huang Jianan
                     ` (3 subsequent siblings)
  4 siblings, 1 reply; 18+ messages in thread
From: Huang Jianan @ 2021-08-23 12:36 UTC (permalink / raw)
  To: u-boot; +Cc: xiang, linux-erofs

From: Huang Jianan <huangjianan@oppo.com>

This patch mainly deals with uncompressed files.

Signed-off-by: Huang Jianan <huangjianan@oppo.com>
---
 fs/Kconfig          |   1 +
 fs/Makefile         |   1 +
 fs/erofs/Kconfig    |  12 ++
 fs/erofs/Makefile   |   7 +
 fs/erofs/data.c     | 124 ++++++++++++++
 fs/erofs/erofs_fs.h | 384 ++++++++++++++++++++++++++++++++++++++++++++
 fs/erofs/fs.c       | 231 ++++++++++++++++++++++++++
 fs/erofs/internal.h | 203 +++++++++++++++++++++++
 fs/erofs/namei.c    | 238 +++++++++++++++++++++++++++
 fs/erofs/super.c    |  65 ++++++++
 fs/fs.c             |  22 +++
 include/erofs.h     |  19 +++
 include/fs.h        |   1 +
 13 files changed, 1308 insertions(+)
 create mode 100644 fs/erofs/Kconfig
 create mode 100644 fs/erofs/Makefile
 create mode 100644 fs/erofs/data.c
 create mode 100644 fs/erofs/erofs_fs.h
 create mode 100644 fs/erofs/fs.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 include/erofs.h

diff --git a/fs/Kconfig b/fs/Kconfig
index 620af7f044..4d04c2c2ce 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -24,4 +24,5 @@ source "fs/yaffs2/Kconfig"
 
 source "fs/squashfs/Kconfig"
 
+source "fs/erofs/Kconfig"
 endmenu
diff --git a/fs/Makefile b/fs/Makefile
index 937cbcf6e8..f05a21c9e6 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -25,5 +25,6 @@ obj-$(CONFIG_CMD_UBIFS) += ubifs/
 obj-$(CONFIG_YAFFS2) += yaffs2/
 obj-$(CONFIG_CMD_ZFS) += zfs/
 obj-$(CONFIG_FS_SQUASHFS) += squashfs/
+obj-$(CONFIG_FS_EROFS) += erofs/
 endif
 obj-y += fs_internal.o
diff --git a/fs/erofs/Kconfig b/fs/erofs/Kconfig
new file mode 100644
index 0000000000..f4b2d51a23
--- /dev/null
+++ b/fs/erofs/Kconfig
@@ -0,0 +1,12 @@
+config FS_EROFS
+	bool "Enable EROFS filesystem support"
+	help
+	  This provides support for reading images from EROFS filesystem.
+	  EROFS (Enhanced Read-Only File System) is a lightweight read-only
+	  file system for scenarios which need high-performance read-only
+	  requirements.
+
+	  It also provides fixed-sized output compression support, which
+	  improves storage density, keeps relatively higher compression
+	  ratios, which is more useful to achieve high performance for
+	  embedded devices with limited memory.
diff --git a/fs/erofs/Makefile b/fs/erofs/Makefile
new file mode 100644
index 0000000000..7398ab7a36
--- /dev/null
+++ b/fs/erofs/Makefile
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0+
+#
+
+obj-$(CONFIG_$(SPL_)FS_EROFS) = fs.o \
+				super.o \
+				namei.o \
+				data.o
diff --git a/fs/erofs/data.c b/fs/erofs/data.c
new file mode 100644
index 0000000000..a0f613264a
--- /dev/null
+++ b/fs/erofs/data.c
@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include "internal.h"
+
+static int erofs_map_blocks_flatmode(struct erofs_inode *inode,
+				     struct erofs_map_blocks *map,
+				     int flags)
+{
+	int err = 0;
+	erofs_blk_t nblocks, lastblk;
+	u64 offset = map->m_la;
+	struct erofs_inode *vi = inode;
+	bool tailendpacking = (vi->datalayout == EROFS_INODE_FLAT_INLINE);
+
+	nblocks = DIV_ROUND_UP(inode->i_size, EROFS_BLKSIZ);
+	lastblk = nblocks - tailendpacking;
+
+	if (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->u.i_blkaddr) + map->m_la;
+		map->m_plen = blknr_to_addr(lastblk) - offset;
+	} else if (tailendpacking) {
+		/* 2 - inode inline B: inode, [xattrs], inline last blk... */
+		map->m_pa = iloc(vi->nid) + vi->inode_isize +
+			vi->xattr_isize + erofs_blkoff(map->m_la);
+		map->m_plen = inode->i_size - offset;
+
+		/* inline data should be located in one meta block */
+		if (erofs_blkoff(map->m_pa) + map->m_plen > PAGE_SIZE) {
+			erofs_err("inline data cross block boundary @ nid %" PRIu64,
+				  vi->nid);
+			DBG_BUGON(1);
+			err = -EFSCORRUPTED;
+			goto err_out;
+		}
+
+		map->m_flags |= EROFS_MAP_META;
+	} else {
+		erofs_err("internal error @ nid: %" PRIu64 " (size %llu), m_la 0x%" PRIx64,
+			  vi->nid, (unsigned long long)inode->i_size, map->m_la);
+		DBG_BUGON(1);
+		err = -EIO;
+		goto err_out;
+	}
+
+out:
+	map->m_llen = map->m_plen;
+
+err_out:
+	return err;
+}
+
+static int erofs_read_raw_data(struct erofs_inode *inode, char *buffer,
+			       erofs_off_t size, erofs_off_t offset)
+{
+	struct erofs_map_blocks map = {
+		.index = UINT_MAX,
+	};
+	int ret;
+	erofs_off_t ptr = offset;
+
+	while (ptr < offset + size) {
+		char *const estart = buffer + ptr - offset;
+		erofs_off_t eend;
+
+		map.m_la = ptr;
+		ret = erofs_map_blocks_flatmode(inode, &map, 0);
+		if (ret)
+			return ret;
+
+		DBG_BUGON(map.m_plen != map.m_llen);
+
+		/* trim extent */
+		eend = min(offset + size, map.m_la + map.m_llen);
+		DBG_BUGON(ptr < map.m_la);
+
+		if (!(map.m_flags & EROFS_MAP_MAPPED)) {
+			if (!map.m_llen) {
+				/* reached EOF */
+				memset(estart, 0, offset + size - ptr);
+				ptr = offset + size;
+				continue;
+			}
+			memset(estart, 0, eend - ptr);
+			ptr = eend;
+			continue;
+		}
+
+		if (ptr > map.m_la) {
+			map.m_pa += ptr - map.m_la;
+			map.m_la = ptr;
+		}
+
+		ret = erofs_dev_read(estart, map.m_pa, eend - map.m_la);
+		if (ret < 0)
+			return -EIO;
+		ptr = eend;
+	}
+	return 0;
+}
+
+int erofs_pread(struct erofs_inode *inode, char *buf,
+		erofs_off_t count, erofs_off_t offset)
+{
+	switch (inode->datalayout) {
+	case EROFS_INODE_FLAT_PLAIN:
+	case EROFS_INODE_FLAT_INLINE:
+		return erofs_read_raw_data(inode, buf, count, offset);
+	case EROFS_INODE_FLAT_COMPRESSION_LEGACY:
+	case EROFS_INODE_FLAT_COMPRESSION:
+		return -EOPNOTSUPP;
+	default:
+		break;
+	}
+	return -EINVAL;
+}
diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
new file mode 100644
index 0000000000..070087fa60
--- /dev/null
+++ b/fs/erofs/erofs_fs.h
@@ -0,0 +1,384 @@
+/* SPDX-License-Identifier: GPL-2.0+ OR Apache-2.0 */
+/*
+ * EROFS (Enhanced ROM File System) on-disk format definition
+ *
+ * Copyright (C) 2017-2018 HUAWEI, Inc.
+ *             http://www.huawei.com/
+ */
+#ifndef __EROFS_FS_H
+#define __EROFS_FS_H
+
+#include <asm/unaligned.h>
+#include <fs.h>
+#include <part.h>
+#include <stdint.h>
+
+#define EROFS_SUPER_MAGIC_V1    0xE0F5E1E2
+#define EROFS_SUPER_OFFSET      1024
+
+#define EROFS_FEATURE_COMPAT_SB_CHKSUM          0x00000001
+
+/*
+ * Any bits that aren't in EROFS_ALL_FEATURE_INCOMPAT should
+ * be incompatible with this kernel version.
+ */
+#define EROFS_FEATURE_INCOMPAT_LZ4_0PADDING	0x00000001
+#define EROFS_FEATURE_INCOMPAT_COMPR_CFGS	0x00000002
+#define EROFS_FEATURE_INCOMPAT_BIG_PCLUSTER	0x00000002
+#define EROFS_ALL_FEATURE_INCOMPAT		\
+	(EROFS_FEATURE_INCOMPAT_LZ4_0PADDING | \
+	 EROFS_FEATURE_INCOMPAT_COMPR_CFGS | \
+	 EROFS_FEATURE_INCOMPAT_BIG_PCLUSTER)
+
+#define EROFS_SB_EXTSLOT_SIZE	16
+
+/* erofs on-disk super block (currently 128 bytes) */
+struct erofs_super_block {
+	__le32 magic;           /* file system magic number */
+	__le32 checksum;        /* crc32c(super_block) */
+	__le32 feature_compat;
+	__u8 blkszbits;         /* support block_size == PAGE_SIZE only */
+	__u8 sb_extslots;	/* superblock size = 128 + sb_extslots * 16 */
+
+	__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 feature_incompat;
+	union {
+		/* bitmap for available compression algorithms */
+		__le16 available_compr_algs;
+		/* customized sliding window size instead of 64k by default */
+		__le16 lz4_max_distance;
+	} __packed u1;
+	__u8 reserved2[42];
+};
+
+/*
+ * 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):
+ * 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 - inode chunk-based E:
+ * inode, [xattrs], chunk indexes ... | ...
+ * 5~7 - reserved
+ */
+enum {
+	EROFS_INODE_FLAT_PLAIN			= 0,
+	EROFS_INODE_FLAT_COMPRESSION_LEGACY	= 1,
+	EROFS_INODE_FLAT_INLINE			= 2,
+	EROFS_INODE_FLAT_COMPRESSION		= 3,
+	EROFS_INODE_CHUNK_BASED			= 4,
+	EROFS_INODE_DATALAYOUT_MAX
+};
+
+static inline bool erofs_inode_is_data_compressed(unsigned int datamode)
+{
+	return datamode == EROFS_INODE_FLAT_COMPRESSION ||
+		datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY;
+}
+
+/* bit definitions of inode i_advise */
+#define EROFS_I_VERSION_BITS            1
+#define EROFS_I_DATALAYOUT_BITS         3
+
+#define EROFS_I_VERSION_BIT             0
+#define EROFS_I_DATALAYOUT_BIT          1
+
+#define EROFS_I_ALL	\
+	((1 << (EROFS_I_DATALAYOUT_BIT + EROFS_I_DATALAYOUT_BITS)) - 1)
+
+/* indicate chunk blkbits, thus 'chunksize = blocksize << chunk blkbits' */
+#define EROFS_CHUNK_FORMAT_BLKBITS_MASK		0x001F
+/* with chunk indexes or just a 4-byte blkaddr array */
+#define EROFS_CHUNK_FORMAT_INDEXES		0x0020
+
+#define EROFS_CHUNK_FORMAT_ALL	\
+	(EROFS_CHUNK_FORMAT_BLKBITS_MASK | EROFS_CHUNK_FORMAT_INDEXES)
+
+struct erofs_inode_chunk_info {
+	__le16 format;		/* chunk blkbits, etc. */
+	__le16 reserved;
+};
+
+/* 32-byte reduced form of an ondisk inode */
+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;
+	__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;
+
+		/* for device files, used to indicate old/new device # */
+		__le32 rdev;
+
+		/* for chunk-based files, it contains the summary info */
+		struct erofs_inode_chunk_info c;
+	} i_u;
+	__le32 i_ino;           /* only used for 32-bit stat compatibility */
+	__le16 i_uid;
+	__le16 i_gid;
+	__le32 i_reserved2;
+};
+
+/* 32 bytes on-disk inode */
+#define EROFS_INODE_LAYOUT_COMPACT	0
+/* 64 bytes on-disk inode */
+#define EROFS_INODE_LAYOUT_EXTENDED	1
+
+/* 64-byte complete form of an ondisk inode */
+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;
+	__le16 i_mode;
+	__le16 i_reserved;
+	__le64 i_size;
+	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;
+
+		/* for chunk-based files, it contains the summary info */
+		struct erofs_inode_chunk_info c;
+	} i_u;
+
+	/* only used for 32-bit stat compatibility */
+	__le32 i_ino;
+
+	__le32 i_uid;
+	__le32 i_gid;
+	__le64 i_ctime;
+	__le32 i_ctime_nsec;
+	__le32 i_nlink;
+	__u8   i_reserved2[16];
+};
+
+#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 */
+};
+
+/* 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 */
+};
+
+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))
+
+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));
+}
+
+/* maximum supported size of a physical compression cluster */
+#define Z_EROFS_PCLUSTER_MAX_SIZE	(1024 * 1024)
+
+/* available compression algorithm types (for h_algorithmtype) */
+enum {
+	Z_EROFS_COMPRESSION_LZ4	= 0,
+	Z_EROFS_COMPRESSION_MAX
+};
+#define Z_EROFS_ALL_COMPR_ALGS		(1 << (Z_EROFS_COMPRESSION_MAX - 1))
+
+/* 14 bytes (+ length field = 16 bytes) */
+struct z_erofs_lz4_cfgs {
+	__le16 max_distance;
+	__le16 max_pclusterblks;
+	u8 reserved[10];
+} __packed;
+
+/*
+ * 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.
+ * bit 1 : HEAD1 big pcluster (0 - off; 1 - on)
+ * bit 2 : HEAD2 big pcluster (0 - off; 1 - on)
+ */
+#define Z_EROFS_ADVISE_COMPACTED_2B		0x0001
+#define Z_EROFS_ADVISE_BIG_PCLUSTER_1		0x0002
+#define Z_EROFS_ADVISE_BIG_PCLUSTER_2		0x0004
+
+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 3-7 : reserved.
+	 */
+	__u8	h_clusterbits;
+};
+
+#define Z_EROFS_VLE_LEGACY_HEADER_PADDING       8
+
+/*
+ * 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)
+ *
+ * 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		= 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
+};
+
+#define Z_EROFS_VLE_DI_CLUSTER_TYPE_BITS        2
+#define Z_EROFS_VLE_DI_CLUSTER_TYPE_BIT         0
+
+/*
+ * D0_CBLKCNT will be marked _only_ at the 1st non-head lcluster to store the
+ * compressed block count of a compressed extent (in logical clusters, aka.
+ * block count of a pcluster).
+ */
+#define Z_EROFS_VLE_DI_D0_CBLKCNT		(1 << 11)
+
+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;
+};
+
+#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;     /* node number */
+	__le16 nameoff; /* start offset of file name */
+	__u8 file_type; /* file type */
+	__u8 reserved;  /* 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_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);
+	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/fs/erofs/fs.c b/fs/erofs/fs.c
new file mode 100644
index 0000000000..0269492d8c
--- /dev/null
+++ b/fs/erofs/fs.c
@@ -0,0 +1,231 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include "internal.h"
+#include <fs_internal.h>
+
+struct erofs_sb_info erofs_sbi;
+
+static struct erofs_ctxt {
+	struct disk_partition cur_part_info;
+	struct blk_desc *cur_dev;
+} ctxt;
+
+int erofs_dev_read(void *buf, u64 offset, size_t len)
+{
+	lbaint_t sect = offset >> ctxt.cur_dev->log2blksz;
+	int off = offset & (ctxt.cur_dev->blksz - 1);
+
+	if (!ctxt.cur_dev)
+		return -EIO;
+
+	if (fs_devread(ctxt.cur_dev, &ctxt.cur_part_info, sect,
+			 off, len, buf))
+		return 0;
+	return -EIO;
+}
+
+int erofs_blk_read(void *buf, erofs_blk_t start, u32 nblocks)
+{
+	return erofs_dev_read(buf, blknr_to_addr(start),
+			 blknr_to_addr(nblocks));
+}
+
+int erofs_probe(struct blk_desc *fs_dev_desc,
+		struct disk_partition *fs_partition)
+{
+	int ret;
+
+	ctxt.cur_dev = fs_dev_desc;
+	ctxt.cur_part_info = *fs_partition;
+
+	ret = erofs_read_superblock();
+	if (ret)
+		goto error;
+
+	return 0;
+error:
+	ctxt.cur_dev = NULL;
+	return ret;
+}
+
+struct erofs_dir_stream {
+	struct fs_dir_stream fs_dirs;
+	struct fs_dirent dirent;
+
+	struct erofs_inode inode;
+	char dblk[EROFS_BLKSIZ];
+	unsigned int maxsize, de_end;
+	erofs_off_t pos;
+};
+
+int erofs_opendir(const char *filename, struct fs_dir_stream **dirsp)
+{
+	struct erofs_dir_stream *dirs;
+	int err;
+
+	dirs = calloc(1, sizeof(*dirs));
+	if (!dirs)
+		return -ENOMEM;
+
+	err = erofs_ilookup(filename, &dirs->inode);
+	if (err)
+		goto err_out;
+
+	if (!S_ISDIR(dirs->inode.i_mode)) {
+		err = -ENOTDIR;
+		goto err_out;
+	}
+	*dirsp = (struct fs_dir_stream *)dirs;
+	return 0;
+err_out:
+	free(dirs);
+	return err;
+}
+
+int erofs_readdir(struct fs_dir_stream *fs_dirs, struct fs_dirent **dentp)
+{
+	struct erofs_dir_stream *dirs = (struct erofs_dir_stream *)fs_dirs;
+	struct fs_dirent *dent = &dirs->dirent;
+	erofs_off_t pos = dirs->pos;
+	unsigned int nameoff, de_namelen;
+	struct erofs_dirent *de;
+	char *de_name;
+	int err;
+
+	if (pos >= dirs->inode.i_size)
+		return 1;
+
+	if (!dirs->maxsize) {
+		dirs->maxsize = min_t(unsigned int, EROFS_BLKSIZ,
+				      dirs->inode.i_size - pos);
+
+		err = erofs_pread(&dirs->inode, dirs->dblk,
+				  dirs->maxsize, pos);
+		if (err)
+			return err;
+
+		de = (struct erofs_dirent *)dirs->dblk;
+		dirs->de_end = le16_to_cpu(de->nameoff);
+		if (dirs->de_end < sizeof(struct erofs_dirent) ||
+		    dirs->de_end >= EROFS_BLKSIZ) {
+			erofs_err("invalid de[0].nameoff %u @ nid %llu",
+				  nameoff, de->nid | 0ULL);
+			return -EFSCORRUPTED;
+		}
+	}
+
+	de = (struct erofs_dirent *)(dirs->dblk + erofs_blkoff(pos));
+	nameoff = le16_to_cpu(de->nameoff);
+	de_name = (char *)dirs->dblk + nameoff;
+
+	/* the last dirent in the block? */
+	if (de + 1 >= (struct erofs_dirent *)(dirs->dblk + dirs->de_end))
+		de_namelen = strnlen(de_name, dirs->maxsize - nameoff);
+	else
+		de_namelen = le16_to_cpu(de[1].nameoff) - nameoff;
+
+	/* a corrupted entry is found */
+	if (nameoff + de_namelen > dirs->maxsize ||
+	    de_namelen > EROFS_NAME_LEN) {
+		erofs_err("bogus dirent @ nid %llu", de->nid | 0ULL);
+		DBG_BUGON(1);
+		return -EFSCORRUPTED;
+	}
+
+	memcpy(dent->name, de_name, de_namelen);
+	dent->name[de_namelen] = '\0';
+
+	if (de->file_type == EROFS_FT_DIR) {
+		dent->type = FS_DT_DIR;
+	} else if (de->file_type == EROFS_FT_SYMLINK) {
+		dent->type = FS_DT_LNK;
+	} else {
+		struct erofs_inode vi;
+
+		dent->type = FS_DT_REG;
+		vi.nid = de->nid;
+
+		err = erofs_read_inode_from_disk(&vi);
+		if (err)
+			return err;
+		dent->size = vi.i_size;
+	}
+	*dentp = dent;
+
+	pos += sizeof(*de);
+	if (erofs_blkoff(pos) >= dirs->de_end) {
+		pos = blknr_to_addr(erofs_blknr(pos) + 1);
+		dirs->maxsize = 0;
+	}
+	dirs->pos = pos;
+	return 0;
+}
+
+void erofs_closedir(struct fs_dir_stream *fs_dirs)
+{
+	free(fs_dirs);
+}
+
+int erofs_exists(const char *filename)
+{
+	struct erofs_inode vi;
+	int err;
+
+	err = erofs_ilookup(filename, &vi);
+	return err == 0;
+}
+
+int erofs_size(const char *filename, loff_t *size)
+{
+	struct erofs_inode vi;
+	int err;
+
+	err = erofs_ilookup(filename, &vi);
+	if (err)
+		return err;
+	*size = vi.i_size;
+	return 0;
+}
+
+int erofs_read(const char *filename, void *buf, loff_t offset, loff_t len,
+	      loff_t *actread)
+{
+	struct erofs_inode vi;
+	int err;
+
+	err = erofs_ilookup(filename, &vi);
+	if (err)
+		return err;
+
+	if (!len)
+		len = vi.i_size;
+
+	err = erofs_pread(&vi, buf, len, offset);
+	if (err) {
+		*actread = 0;
+		return err;
+	}
+
+	if (offset >= vi.i_size)
+		*actread = 0;
+	else if (offset + len > vi.i_size)
+		*actread = vi.i_size - offset;
+	else
+		*actread = len;
+	return 0;
+}
+
+void erofs_close(void)
+{
+	ctxt.cur_dev = NULL;
+}
+
+int erofs_uuid(char *uuid_str)
+{
+#ifdef CONFIG_LIB_UUID
+	if (ctxt.cur_dev)
+		uuid_bin_to_str(erofs_sbi.uuid, uuid_str,
+				UUID_STR_FORMAT_STD);
+	return 0;
+#endif
+	return -ENOSYS;
+}
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
new file mode 100644
index 0000000000..02dfd7ead4
--- /dev/null
+++ b/fs/erofs/internal.h
@@ -0,0 +1,203 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+#ifndef __EROFS_INTERNAL_H
+#define __EROFS_INTERNAL_H
+
+#define __packed __attribute__((__packed__))
+
+#include <linux/stat.h>
+#include <linux/bug.h>
+#include <linux/err.h>
+#include <linux/printk.h>
+#include <inttypes.h>
+#include "erofs_fs.h"
+
+#define erofs_err(fmt, ...)	\
+	pr_err(fmt "\n", ##__VA_ARGS__)
+
+#define erofs_info(fmt, ...)	\
+	pr_info(fmt "\n", ##__VA_ARGS__)
+
+#define erofs_dbg(fmt, ...)	\
+	pr_debug(fmt "\n", ##__VA_ARGS__)
+
+#define DBG_BUGON(condition)	BUG_ON(condition)
+
+/* no obvious reason to support explicit PAGE_SIZE != 4096 for now */
+#if PAGE_SIZE != 4096
+#error incompatible PAGE_SIZE is already defined
+#endif
+
+#define PAGE_MASK		(~(PAGE_SIZE-1))
+
+#define LOG_BLOCK_SIZE          (12)
+#define EROFS_BLKSIZ            (1U << LOG_BLOCK_SIZE)
+
+#define EROFS_ISLOTBITS		5
+#define EROFS_SLOTSIZE		(1U << EROFS_ISLOTBITS)
+
+typedef u64 erofs_off_t;
+typedef u64 erofs_nid_t;
+/* data type for filesystem-wide blocks number */
+typedef u32 erofs_blk_t;
+
+#define NULL_ADDR	((unsigned int)-1)
+#define NULL_ADDR_UL	((unsigned long)-1)
+
+#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)
+
+#define BLK_ROUND_UP(addr)	DIV_ROUND_UP(addr, EROFS_BLKSIZ)
+
+struct erofs_sb_info {
+	u64 blocks;
+
+	erofs_blk_t meta_blkaddr;
+	erofs_blk_t xattr_blkaddr;
+
+	u32 feature_compat;
+	u32 feature_incompat;
+	u64 build_time;
+	u32 build_time_nsec;
+
+	unsigned char islotbits;
+
+	/* 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];
+
+	u16 available_compr_algs;
+	u16 lz4_max_distance;
+};
+
+/* global sbi */
+extern struct erofs_sb_info erofs_sbi;
+
+static inline erofs_off_t iloc(erofs_nid_t nid)
+{
+	return blknr_to_addr(erofs_sbi.meta_blkaddr) +
+		(nid << erofs_sbi.islotbits);
+}
+
+#define EROFS_FEATURE_FUNCS(name, compat, feature) \
+static inline bool erofs_sb_has_##name(void) \
+{ \
+	return erofs_sbi.feature_##compat & EROFS_FEATURE_##feature; \
+}
+
+EROFS_FEATURE_FUNCS(lz4_0padding, incompat, INCOMPAT_LZ4_0PADDING)
+EROFS_FEATURE_FUNCS(compr_cfgs, incompat, INCOMPAT_COMPR_CFGS)
+EROFS_FEATURE_FUNCS(big_pcluster, incompat, INCOMPAT_BIG_PCLUSTER)
+EROFS_FEATURE_FUNCS(sb_chksum, compat, COMPAT_SB_CHKSUM)
+
+#define EROFS_I_EA_INITED	(1 << 0)
+#define EROFS_I_Z_INITED	(1 << 1)
+
+struct erofs_inode {
+	unsigned int flags;
+	umode_t i_mode;
+	erofs_off_t i_size;
+
+	u64 i_ino[2];
+	u32 i_uid;
+	u32 i_gid;
+	u64 i_ctime;
+	u32 i_ctime_nsec;
+	u32 i_nlink;
+
+	union {
+		u32 i_blkaddr;
+		u32 i_blocks;
+		u32 i_rdev;
+	} u;
+
+	unsigned char datalayout;
+	unsigned char inode_isize;
+	unsigned int xattr_isize;
+	unsigned int extent_isize;
+
+	erofs_nid_t nid;
+
+	struct {
+		uint16_t z_advise;
+		uint8_t  z_algorithmtype[2];
+		uint8_t  z_logical_clusterbits;
+	};
+};
+
+static inline bool is_inode_layout_compression(struct erofs_inode *inode)
+{
+	return erofs_inode_is_data_compressed(inode->datalayout);
+}
+
+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_bitrange(value, EROFS_I_VERSION_BIT,
+			      EROFS_I_VERSION_BITS);
+}
+
+static inline unsigned int erofs_inode_datalayout(unsigned int value)
+{
+	return erofs_bitrange(value, EROFS_I_DATALAYOUT_BIT,
+			      EROFS_I_DATALAYOUT_BITS);
+}
+
+#define IS_ROOT(x)	((x) == (x)->i_parent)
+
+static inline bool is_dot_dotdot(const char *name)
+{
+	if (name[0] != '.')
+		return false;
+
+	return name[1] == '\0' || (name[1] == '.' && name[2] == '\0');
+}
+
+enum {
+	BH_Meta,
+	BH_Mapped,
+	BH_Zipped,
+	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)
+/* 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 {
+	char mpage[EROFS_BLKSIZ];
+
+	erofs_off_t m_pa, m_la;
+	u64 m_plen, m_llen;
+
+	unsigned int m_flags;
+	erofs_blk_t index;
+};
+
+int erofs_blk_read(void *buf, erofs_blk_t start, u32 nblocks);
+int erofs_dev_read(void *buf, u64 offset, size_t len);
+
+int erofs_read_superblock(void);
+int erofs_read_inode_from_disk(struct erofs_inode *vi);
+int erofs_ilookup(const char *path, struct erofs_inode *vi);
+int erofs_pread(struct erofs_inode *inode, char *buf,
+		erofs_off_t count, erofs_off_t offset);
+int z_erofs_fill_inode(struct erofs_inode *vi);
+int z_erofs_map_blocks_iter(struct erofs_inode *vi,
+			    struct erofs_map_blocks *map);
+
+#define EFSCORRUPTED	EUCLEAN		/* Filesystem is corrupted */
+#endif
diff --git a/fs/erofs/namei.c b/fs/erofs/namei.c
new file mode 100644
index 0000000000..4c5d614483
--- /dev/null
+++ b/fs/erofs/namei.c
@@ -0,0 +1,238 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include "internal.h"
+
+int erofs_read_inode_from_disk(struct erofs_inode *vi)
+{
+	int ret, ifmt;
+	char buf[sizeof(struct erofs_inode_extended)];
+	struct erofs_inode_compact *dic;
+	struct erofs_inode_extended *die;
+	const erofs_off_t inode_loc = iloc(vi->nid);
+
+	ret = erofs_dev_read(buf, inode_loc, sizeof(*dic));
+	if (ret < 0)
+		return -EIO;
+
+	dic = (struct erofs_inode_compact *)buf;
+	ifmt = le16_to_cpu(dic->i_format);
+
+	vi->datalayout = erofs_inode_datalayout(ifmt);
+	if (vi->datalayout >= EROFS_INODE_DATALAYOUT_MAX) {
+		erofs_err("unsupported datalayout %u of nid %llu",
+			  vi->datalayout, vi->nid | 0ULL);
+		return -EOPNOTSUPP;
+	}
+	switch (erofs_inode_version(ifmt)) {
+	case EROFS_INODE_LAYOUT_EXTENDED:
+		vi->inode_isize = sizeof(struct erofs_inode_extended);
+
+		ret = erofs_dev_read(buf + sizeof(*dic), inode_loc + sizeof(*dic),
+			       sizeof(*die) - sizeof(*dic));
+		if (ret < 0)
+			return -EIO;
+
+		die = (struct erofs_inode_extended *)buf;
+		vi->xattr_isize = erofs_xattr_ibody_size(die->i_xattr_icount);
+		vi->i_mode = le16_to_cpu(die->i_mode);
+
+		switch (vi->i_mode & S_IFMT) {
+		case S_IFREG:
+		case S_IFDIR:
+		case S_IFLNK:
+			vi->u.i_blkaddr = le32_to_cpu(die->i_u.raw_blkaddr);
+			break;
+		case S_IFCHR:
+		case S_IFBLK:
+			vi->u.i_rdev = 0;
+			break;
+		case S_IFIFO:
+		case S_IFSOCK:
+			vi->u.i_rdev = 0;
+			break;
+		default:
+			goto bogusimode;
+		}
+
+		vi->i_uid = le32_to_cpu(die->i_uid);
+		vi->i_gid = le32_to_cpu(die->i_gid);
+		vi->i_nlink = le32_to_cpu(die->i_nlink);
+
+		vi->i_ctime = le64_to_cpu(die->i_ctime);
+		vi->i_ctime_nsec = le64_to_cpu(die->i_ctime_nsec);
+		vi->i_size = le64_to_cpu(die->i_size);
+		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);
+		vi->i_mode = le16_to_cpu(dic->i_mode);
+
+		switch (vi->i_mode & S_IFMT) {
+		case S_IFREG:
+		case S_IFDIR:
+		case S_IFLNK:
+			vi->u.i_blkaddr = le32_to_cpu(dic->i_u.raw_blkaddr);
+			break;
+		case S_IFCHR:
+		case S_IFBLK:
+			vi->u.i_rdev = 0;
+			break;
+		case S_IFIFO:
+		case S_IFSOCK:
+			vi->u.i_rdev = 0;
+			break;
+		default:
+			goto bogusimode;
+		}
+
+		vi->i_uid = le16_to_cpu(dic->i_uid);
+		vi->i_gid = le16_to_cpu(dic->i_gid);
+		vi->i_nlink = le16_to_cpu(dic->i_nlink);
+
+		vi->i_ctime = erofs_sbi.build_time;
+		vi->i_ctime_nsec = erofs_sbi.build_time_nsec;
+
+		vi->i_size = le32_to_cpu(dic->i_size);
+		break;
+	default:
+		erofs_err("unsupported on-disk inode version %u of nid %llu",
+			  erofs_inode_version(ifmt), vi->nid | 0ULL);
+		return -EOPNOTSUPP;
+	}
+
+	vi->flags = 0;
+	if (erofs_inode_is_data_compressed(vi->datalayout))
+		return -EOPNOTSUPP;
+	return 0;
+bogusimode:
+	erofs_err("bogus i_mode (%o) @ nid %llu", vi->i_mode, vi->nid | 0ULL);
+	return -EFSCORRUPTED;
+}
+
+struct erofs_dirent *find_target_dirent(erofs_nid_t pnid,
+					void *dentry_blk,
+					const char *name, unsigned int len,
+					unsigned int nameoff,
+					unsigned int maxsize)
+{
+	struct erofs_dirent *de = dentry_blk;
+	const struct erofs_dirent *end = dentry_blk + nameoff;
+
+	while (de < end) {
+		const char *de_name;
+		unsigned int de_namelen;
+
+		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 (nameoff + de_namelen > maxsize ||
+		    de_namelen > EROFS_NAME_LEN) {
+			erofs_err("bogus dirent @ nid %llu", pnid | 0ULL);
+			DBG_BUGON(1);
+			return ERR_PTR(-EFSCORRUPTED);
+		}
+
+		if (len == de_namelen && !memcmp(de_name, name, de_namelen))
+			return de;
+		++de;
+	}
+	return NULL;
+}
+
+struct nameidata {
+	erofs_nid_t	nid;
+	unsigned int	ftype;
+};
+
+int erofs_namei(struct nameidata *nd,
+		const char *name, unsigned int len)
+{
+	erofs_nid_t nid = nd->nid;
+	int ret;
+	char buf[EROFS_BLKSIZ];
+	struct erofs_inode vi = { .nid = nid };
+	erofs_off_t offset;
+
+	ret = erofs_read_inode_from_disk(&vi);
+	if (ret)
+		return ret;
+
+	offset = 0;
+	while (offset < vi.i_size) {
+		erofs_off_t maxsize = min_t(erofs_off_t,
+					    vi.i_size - offset, EROFS_BLKSIZ);
+		struct erofs_dirent *de = (void *)buf;
+		unsigned int nameoff;
+
+		ret = erofs_pread(&vi, buf, maxsize, offset);
+		if (ret)
+			return ret;
+
+		nameoff = le16_to_cpu(de->nameoff);
+		if (nameoff < sizeof(struct erofs_dirent) ||
+		    nameoff >= PAGE_SIZE) {
+			erofs_err("invalid de[0].nameoff %u @ nid %llu",
+				  nameoff, nid | 0ULL);
+			return -EFSCORRUPTED;
+		}
+
+		de = find_target_dirent(nid, buf, name, len,
+					nameoff, maxsize);
+		if (IS_ERR(de))
+			return PTR_ERR(de);
+
+		if (de) {
+			nd->nid = le64_to_cpu(de->nid);
+			return 0;
+		}
+		offset += maxsize;
+	}
+	return -ENOENT;
+}
+
+static int link_path_walk(const char *name, struct nameidata *nd)
+{
+	nd->nid = erofs_sbi.root_nid;
+
+	while (*name == '/')
+		name++;
+
+	/* At this point we know we have a real path component. */
+	while (*name != '\0') {
+		const char *p = name;
+		int ret;
+
+		do {
+			++p;
+		} while (*p != '\0' && *p != '/');
+
+		DBG_BUGON(p <= name);
+		ret = erofs_namei(nd, name, p - name);
+		if (ret)
+			return ret;
+
+		name = p;
+		/* Skip until no more slashes. */
+		for (name = p; *name == '/'; ++name);
+	}
+	return 0;
+}
+
+int erofs_ilookup(const char *path, struct erofs_inode *vi)
+{
+	int ret;
+	struct nameidata nd;
+
+	ret = link_path_walk(path, &nd);
+	if (ret)
+		return ret;
+
+	vi->nid = nd.nid;
+	return erofs_read_inode_from_disk(vi);
+}
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
new file mode 100644
index 0000000000..c58a826b4b
--- /dev/null
+++ b/fs/erofs/super.c
@@ -0,0 +1,65 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include "internal.h"
+
+static bool check_layout_compatibility(struct erofs_sb_info *sbi,
+				       struct erofs_super_block *dsb)
+{
+	const unsigned int feature = le32_to_cpu(dsb->feature_incompat);
+
+	sbi->feature_incompat = feature;
+
+	/* check if current kernel meets all mandatory requirements */
+	if (feature & (~EROFS_ALL_FEATURE_INCOMPAT)) {
+		erofs_err("unidentified incompatible feature %x, please upgrade kernel version",
+			  feature & ~EROFS_ALL_FEATURE_INCOMPAT);
+		return false;
+	}
+	return true;
+}
+
+int erofs_read_superblock(void)
+{
+	char data[EROFS_BLKSIZ];
+	struct erofs_super_block *dsb;
+	unsigned int blkszbits;
+	int ret;
+
+	ret = erofs_blk_read(data, 0, 1);
+	if (ret < 0) {
+		erofs_err("cannot read erofs superblock: %d", ret);
+		return -EIO;
+	}
+	dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET);
+
+	ret = -EINVAL;
+	if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) {
+		erofs_err("cannot find valid erofs superblock");
+		return ret;
+	}
+
+	erofs_sbi.feature_compat = le32_to_cpu(dsb->feature_compat);
+
+	blkszbits = dsb->blkszbits;
+	/* 9(512 bytes) + LOG_SECTORS_PER_BLOCK == LOG_BLOCK_SIZE */
+	if (blkszbits != LOG_BLOCK_SIZE) {
+		erofs_err("blksize %u isn't supported on this platform",
+			  1 << blkszbits);
+		return ret;
+	}
+
+	if (!check_layout_compatibility(&erofs_sbi, dsb))
+		return ret;
+
+	erofs_sbi.blocks = le32_to_cpu(dsb->blocks);
+	erofs_sbi.meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr);
+	erofs_sbi.xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr);
+	erofs_sbi.islotbits = EROFS_ISLOTBITS;
+	erofs_sbi.root_nid = le16_to_cpu(dsb->root_nid);
+	erofs_sbi.inos = le64_to_cpu(dsb->inos);
+
+	erofs_sbi.build_time = le64_to_cpu(dsb->build_time);
+	erofs_sbi.build_time_nsec = le32_to_cpu(dsb->build_time_nsec);
+
+	memcpy(&erofs_sbi.uuid, dsb->uuid, sizeof(dsb->uuid));
+	return 0;
+}
diff --git a/fs/fs.c b/fs/fs.c
index 7c682582c8..3c06b0252b 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -26,6 +26,7 @@
 #include <linux/math64.h>
 #include <efi_loader.h>
 #include <squashfs.h>
+#include <erofs.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -304,6 +305,27 @@ static struct fstype_info fstypes[] = {
 		.unlink = fs_unlink_unsupported,
 		.mkdir = fs_mkdir_unsupported,
 	},
+#endif
+#if IS_ENABLED(CONFIG_FS_EROFS)
+	{
+		.fstype = FS_TYPE_EROFS,
+		.name = "erofs",
+		.null_dev_desc_ok = false,
+		.probe = erofs_probe,
+		.opendir = erofs_opendir,
+		.readdir = erofs_readdir,
+		.ls = fs_ls_generic,
+		.read = erofs_read,
+		.size = erofs_size,
+		.close = erofs_close,
+		.closedir = erofs_closedir,
+		.exists = erofs_exists,
+		.uuid = fs_uuid_unsupported,
+		.write = fs_write_unsupported,
+		.ln = fs_ln_unsupported,
+		.unlink = fs_unlink_unsupported,
+		.mkdir = fs_mkdir_unsupported,
+	},
 #endif
 	{
 		.fstype = FS_TYPE_ANY,
diff --git a/include/erofs.h b/include/erofs.h
new file mode 100644
index 0000000000..79de78257f
--- /dev/null
+++ b/include/erofs.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _EROFS_H_
+#define _EROFS_H_
+
+struct disk_partition;
+
+int erofs_opendir(const char *filename, struct fs_dir_stream **dirsp);
+int erofs_readdir(struct fs_dir_stream *dirs, struct fs_dirent **dentp);
+int erofs_probe(struct blk_desc *fs_dev_desc,
+	       struct disk_partition *fs_partition);
+int erofs_read(const char *filename, void *buf, loff_t offset,
+	      loff_t len, loff_t *actread);
+int erofs_size(const char *filename, loff_t *size);
+int erofs_exists(const char *filename);
+void erofs_close(void);
+void erofs_closedir(struct fs_dir_stream *dirs);
+int erofs_uuid(char *uuid_str);
+
+#endif /* _EROFS_H  */
diff --git a/include/fs.h b/include/fs.h
index 1c79e299fd..f96afc4c89 100644
--- a/include/fs.h
+++ b/include/fs.h
@@ -17,6 +17,7 @@ struct cmd_tbl;
 #define FS_TYPE_UBIFS	4
 #define FS_TYPE_BTRFS	5
 #define FS_TYPE_SQUASHFS 6
+#define FS_TYPE_EROFS   7
 
 struct blk_desc;
 
-- 
2.25.1


^ permalink raw reply	[flat|nested] 18+ messages in thread

* [PATCH v2 2/3] fs/erofs: add lz4 1.8.3 decompressor
  2021-08-23 12:36 ` [PATCH v2 0/3] " Huang Jianan
  2021-08-23 12:36   ` [PATCH v2 1/3] fs/erofs: add erofs filesystem support Huang Jianan
@ 2021-08-23 12:36   ` Huang Jianan
  2021-08-25 22:39     ` Tom Rini
  2021-08-23 12:36   ` [PATCH v2 3/3] fs/erofs: add lz4 decompression support Huang Jianan
                     ` (2 subsequent siblings)
  4 siblings, 1 reply; 18+ messages in thread
From: Huang Jianan @ 2021-08-23 12:36 UTC (permalink / raw)
  To: u-boot; +Cc: xiang, linux-erofs

From: Huang Jianan <huangjianan@oppo.com>

In order to use the newest LZ4_decompress_safe_partial() which can
now decode exactly the nb of bytes requested.

Signed-off-by: Huang Jianan <huangjianan@oppo.com>
---
 fs/erofs/Makefile |   3 +-
 fs/erofs/lz4.c    | 534 ++++++++++++++++++++++++++++++++++++++++++++++
 fs/erofs/lz4.h    |   5 +
 3 files changed, 541 insertions(+), 1 deletion(-)
 create mode 100644 fs/erofs/lz4.c
 create mode 100644 fs/erofs/lz4.h

diff --git a/fs/erofs/Makefile b/fs/erofs/Makefile
index 7398ab7a36..c4fc5b794e 100644
--- a/fs/erofs/Makefile
+++ b/fs/erofs/Makefile
@@ -4,4 +4,5 @@
 obj-$(CONFIG_$(SPL_)FS_EROFS) = fs.o \
 				super.o \
 				namei.o \
-				data.o
+				data.o \
+				lz4.o
diff --git a/fs/erofs/lz4.c b/fs/erofs/lz4.c
new file mode 100644
index 0000000000..35f67c15eb
--- /dev/null
+++ b/fs/erofs/lz4.c
@@ -0,0 +1,534 @@
+// SPDX-License-Identifier: GPL 2.0+ OR BSD-2-Clause
+/*
+ * LZ4 - Fast LZ compression algorithm
+ * Copyright (C) 2011 - 2016, Yann Collet.
+ * BSD 2 - Clause License (http://www.opensource.org/licenses/bsd - license.php)
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *	* Redistributions of source code must retain the above copyright
+ *	  notice, this list of conditions and the following disclaimer.
+ *	* Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * You can contact the author at :
+ *	- LZ4 homepage : http://www.lz4.org
+ *	- LZ4 source repository : https://github.com/lz4/lz4
+ */
+#include <common.h>
+#include <compiler.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/bug.h>
+#include <asm/unaligned.h>
+
+#define FORCE_INLINE inline __attribute__((always_inline))
+
+static FORCE_INLINE u16 LZ4_readLE16(const void *src)
+{
+	return get_unaligned_le16(src);
+}
+
+static FORCE_INLINE void LZ4_copy8(void *dst, const void *src)
+{
+	put_unaligned(get_unaligned((const u64 *)src), (u64 *)dst);
+}
+
+typedef  uint8_t BYTE;
+typedef uint16_t U16;
+typedef uint32_t U32;
+typedef  int32_t S32;
+typedef uint64_t U64;
+typedef uintptr_t uptrval;
+
+static FORCE_INLINE void LZ4_write32(void *memPtr, U32 value)
+{
+	put_unaligned(value, (U32 *)memPtr);
+}
+
+/**************************************
+*  Reading and writing into memory
+**************************************/
+
+/* customized version of memcpy, which may overwrite up to 7 bytes beyond dstEnd */
+static void LZ4_wildCopy(void* dstPtr, const void* srcPtr, void* dstEnd)
+{
+    BYTE* d = (BYTE*)dstPtr;
+    const BYTE* s = (const BYTE*)srcPtr;
+    BYTE* e = (BYTE*)dstEnd;
+    do { LZ4_copy8(d,s); d+=8; s+=8; } while (d<e);
+}
+
+
+/**************************************
+*  Common Constants
+**************************************/
+#define MINMATCH 4
+
+#define WILDCOPYLENGTH 8
+#define LASTLITERALS 5
+#define MFLIMIT (WILDCOPYLENGTH + MINMATCH)
+
+/*
+ * ensure it's possible to write 2 x wildcopyLength
+ * without overflowing output buffer
+ */
+#define MATCH_SAFEGUARD_DISTANCE  ((2 * WILDCOPYLENGTH) - MINMATCH)
+
+#define KB (1 <<10)
+
+#define MAXD_LOG 16
+#define MAX_DISTANCE ((1 << MAXD_LOG) - 1)
+
+#define ML_BITS  4
+#define ML_MASK  ((1U<<ML_BITS)-1)
+#define RUN_BITS (8-ML_BITS)
+#define RUN_MASK ((1U<<RUN_BITS)-1)
+
+#define LZ4_STATIC_ASSERT(c)	BUILD_BUG_ON(!(c))
+
+/**************************************
+*  Local Structures and types
+**************************************/
+typedef enum { noDict = 0, withPrefix64k, usingExtDict } dict_directive;
+typedef enum { endOnOutputSize = 0, endOnInputSize = 1 } endCondition_directive;
+typedef enum { decode_full_block = 0, partial_decode = 1 } earlyEnd_directive;
+
+#define DEBUGLOG(l, ...) {}	/* disabled */
+
+#ifndef assert
+#define assert(condition) ((void)0)
+#endif
+
+/*
+ * LZ4_decompress_generic() :
+ * This generic decompression function covers all use cases.
+ * It shall be instantiated several times, using different sets of directives.
+ * Note that it is important for performance that this function really get inlined,
+ * in order to remove useless branches during compilation optimization.
+ */
+static FORCE_INLINE int LZ4_decompress_generic(
+	 const char * const src,
+	 char * const dst,
+	 int srcSize,
+		/*
+		 * If endOnInput == endOnInputSize,
+		 * this value is `dstCapacity`
+		 */
+	 int outputSize,
+	 /* endOnOutputSize, endOnInputSize */
+	 endCondition_directive endOnInput,
+	 /* full, partial */
+	 earlyEnd_directive partialDecoding,
+	 /* noDict, withPrefix64k, usingExtDict */
+	 dict_directive dict,
+	 /* always <= dst, == dst when no prefix */
+	 const BYTE * const lowPrefix,
+	 /* only if dict == usingExtDict */
+	 const BYTE * const dictStart,
+	 /* note : = 0 if noDict */
+	 const size_t dictSize
+	 )
+{
+	const BYTE *ip = (const BYTE *) src;
+	const BYTE * const iend = ip + srcSize;
+
+	BYTE *op = (BYTE *) dst;
+	BYTE * const oend = op + outputSize;
+	BYTE *cpy;
+
+	const BYTE * const dictEnd = (const BYTE *)dictStart + dictSize;
+	static const unsigned int inc32table[8] = {0, 1, 2, 1, 0, 4, 4, 4};
+	static const int dec64table[8] = {0, 0, 0, -1, -4, 1, 2, 3};
+
+	const int safeDecode = (endOnInput == endOnInputSize);
+	const int checkOffset = ((safeDecode) && (dictSize < (int)(64 * KB)));
+
+	/* Set up the "end" pointers for the shortcut. */
+	const BYTE *const shortiend = iend -
+		(endOnInput ? 14 : 8) /*maxLL*/ - 2 /*offset*/;
+	const BYTE *const shortoend = oend -
+		(endOnInput ? 14 : 8) /*maxLL*/ - 18 /*maxML*/;
+
+	DEBUGLOG(5, "%s (srcSize:%i, dstSize:%i)", __func__,
+		 srcSize, outputSize);
+
+	/* Special cases */
+	assert(lowPrefix <= op);
+	assert(src != NULL);
+
+	/* Empty output buffer */
+	if ((endOnInput) && (unlikely(outputSize == 0)))
+		return ((srcSize == 1) && (*ip == 0)) ? 0 : -1;
+
+	if ((!endOnInput) && (unlikely(outputSize == 0)))
+		return (*ip == 0 ? 1 : -1);
+
+	if ((endOnInput) && unlikely(srcSize == 0))
+		return -1;
+
+	/* Main Loop : decode sequences */
+	while (1) {
+		size_t length;
+		const BYTE *match;
+		size_t offset;
+
+		/* get literal length */
+		unsigned int const token = *ip++;
+		length = token>>ML_BITS;
+
+		/* ip < iend before the increment */
+		assert(!endOnInput || ip <= iend);
+
+		/*
+		 * A two-stage shortcut for the most common case:
+		 * 1) If the literal length is 0..14, and there is enough
+		 * space, enter the shortcut and copy 16 bytes on behalf
+		 * of the literals (in the fast mode, only 8 bytes can be
+		 * safely copied this way).
+		 * 2) Further if the match length is 4..18, copy 18 bytes
+		 * in a similar manner; but we ensure that there's enough
+		 * space in the output for those 18 bytes earlier, upon
+		 * entering the shortcut (in other words, there is a
+		 * combined check for both stages).
+		 *
+		 * The & in the likely() below is intentionally not && so that
+		 * some compilers can produce better parallelized runtime code
+		 */
+		if ((endOnInput ? length != RUN_MASK : length <= 8)
+		   /*
+		    * strictly "less than" on input, to re-enter
+		    * the loop with at least one byte
+		    */
+		   && likely((endOnInput ? ip < shortiend : 1) &
+			     (op <= shortoend))) {
+			/* Copy the literals */
+			memcpy(op, ip, endOnInput ? 16 : 8);
+			op += length; ip += length;
+
+			/*
+			 * The second stage:
+			 * prepare for match copying, decode full info.
+			 * If it doesn't work out, the info won't be wasted.
+			 */
+			length = token & ML_MASK; /* match length */
+			offset = LZ4_readLE16(ip);
+			ip += 2;
+			match = op - offset;
+			assert(match <= op); /* check overflow */
+
+			/* Do not deal with overlapping matches. */
+			if ((length != ML_MASK) &&
+			    (offset >= 8) &&
+			    (dict == withPrefix64k || match >= lowPrefix)) {
+				/* Copy the match. */
+				memcpy(op + 0, match + 0, 8);
+				memcpy(op + 8, match + 8, 8);
+				memcpy(op + 16, match + 16, 2);
+				op += length + MINMATCH;
+				/* Both stages worked, load the next token. */
+				continue;
+			}
+
+			/*
+			 * The second stage didn't work out, but the info
+			 * is ready. Propel it right to the point of match
+			 * copying.
+			 */
+			goto _copy_match;
+		}
+
+		/* decode literal length */
+		if (length == RUN_MASK) {
+			unsigned int s;
+
+			if (unlikely(endOnInput ? ip >= iend - RUN_MASK : 0)) {
+				/* overflow detection */
+				goto _output_error;
+			}
+			do {
+				s = *ip++;
+				length += s;
+			} while (likely(endOnInput
+				? ip < iend - RUN_MASK
+				: 1) & (s == 255));
+
+			if ((safeDecode)
+			    && unlikely((uptrval)(op) +
+					length < (uptrval)(op))) {
+				/* overflow detection */
+				goto _output_error;
+			}
+			if ((safeDecode)
+			    && unlikely((uptrval)(ip) +
+					length < (uptrval)(ip))) {
+				/* overflow detection */
+				goto _output_error;
+			}
+		}
+
+		/* copy literals */
+		cpy = op + length;
+		LZ4_STATIC_ASSERT(MFLIMIT >= WILDCOPYLENGTH);
+
+		if (((endOnInput) && ((cpy > oend - MFLIMIT)
+			|| (ip + length > iend - (2 + 1 + LASTLITERALS))))
+			|| ((!endOnInput) && (cpy > oend - WILDCOPYLENGTH))) {
+			if (partialDecoding) {
+				if (cpy > oend) {
+					/*
+					 * Partial decoding :
+					 * stop in the middle of literal segment
+					 */
+					cpy = oend;
+					length = oend - op;
+				}
+				if ((endOnInput)
+					&& (ip + length > iend)) {
+					/*
+					 * Error :
+					 * read attempt beyond
+					 * end of input buffer
+					 */
+					goto _output_error;
+				}
+			} else {
+				if ((!endOnInput)
+					&& (cpy != oend)) {
+					/*
+					 * Error :
+					 * block decoding must
+					 * stop exactly there
+					 */
+					goto _output_error;
+				}
+				if ((endOnInput)
+					&& ((ip + length != iend)
+					|| (cpy > oend))) {
+					/*
+					 * Error :
+					 * input must be consumed
+					 */
+					goto _output_error;
+				}
+			}
+
+			/*
+			 * supports overlapping memory regions; only matters
+			 * for in-place decompression scenarios
+			 */
+			memmove(op, ip, length);
+			ip += length;
+			op += length;
+
+			/* Necessarily EOF, due to parsing restrictions */
+			if (!partialDecoding || (cpy == oend))
+				break;
+		} else {
+			/* may overwrite up to WILDCOPYLENGTH beyond cpy */
+			LZ4_wildCopy(op, ip, cpy);
+			ip += length;
+			op = cpy;
+		}
+
+		/* get offset */
+		offset = LZ4_readLE16(ip);
+		ip += 2;
+		match = op - offset;
+
+		/* get matchlength */
+		length = token & ML_MASK;
+
+_copy_match:
+		if ((checkOffset) && (unlikely(match + dictSize < lowPrefix))) {
+			/* Error : offset outside buffers */
+			goto _output_error;
+		}
+
+		/* costs ~1%; silence an msan warning when offset == 0 */
+		/*
+		 * note : when partialDecoding, there is no guarantee that
+		 * at least 4 bytes remain available in output buffer
+		 */
+		if (!partialDecoding) {
+			assert(oend > op);
+			assert(oend - op >= 4);
+
+			LZ4_write32(op, (U32)offset);
+		}
+
+		if (length == ML_MASK) {
+			unsigned int s;
+
+			do {
+				s = *ip++;
+
+				if ((endOnInput) && (ip > iend - LASTLITERALS))
+					goto _output_error;
+
+				length += s;
+			} while (s == 255);
+
+			if ((safeDecode)
+				&& unlikely(
+					(uptrval)(op) + length < (uptrval)op)) {
+				/* overflow detection */
+				goto _output_error;
+			}
+		}
+
+		length += MINMATCH;
+
+		/* match starting within external dictionary */
+		if ((dict == usingExtDict) && (match < lowPrefix)) {
+			if (unlikely(op + length > oend - LASTLITERALS)) {
+				/* doesn't respect parsing restriction */
+				if (!partialDecoding)
+					goto _output_error;
+				length = min(length, (size_t)(oend - op));
+			}
+
+			if (length <= (size_t)(lowPrefix - match)) {
+				/*
+				 * match fits entirely within external
+				 * dictionary : just copy
+				 */
+				memmove(op, dictEnd - (lowPrefix - match),
+					length);
+				op += length;
+			} else {
+				/*
+				 * match stretches into both external
+				 * dictionary and current block
+				 */
+				size_t const copySize = (size_t)(lowPrefix - match);
+				size_t const restSize = length - copySize;
+
+				memcpy(op, dictEnd - copySize, copySize);
+				op += copySize;
+				if (restSize > (size_t)(op - lowPrefix)) {
+					/* overlap copy */
+					BYTE * const endOfMatch = op + restSize;
+					const BYTE *copyFrom = lowPrefix;
+
+					while (op < endOfMatch)
+						*op++ = *copyFrom++;
+				} else {
+					memcpy(op, lowPrefix, restSize);
+					op += restSize;
+				}
+			}
+			continue;
+		}
+
+		/* copy match within block */
+		cpy = op + length;
+
+		/*
+		 * partialDecoding :
+		 * may not respect endBlock parsing restrictions
+		 */
+		assert(op <= oend);
+		if (partialDecoding &&
+		    (cpy > oend - MATCH_SAFEGUARD_DISTANCE)) {
+			size_t const mlen = min(length, (size_t)(oend - op));
+			const BYTE * const matchEnd = match + mlen;
+			BYTE * const copyEnd = op + mlen;
+
+			if (matchEnd > op) {
+				/* overlap copy */
+				while (op < copyEnd)
+					*op++ = *match++;
+			} else {
+				memcpy(op, match, mlen);
+			}
+			op = copyEnd;
+			if (op == oend)
+				break;
+			continue;
+		}
+
+		if (unlikely(offset < 8)) {
+			op[0] = match[0];
+			op[1] = match[1];
+			op[2] = match[2];
+			op[3] = match[3];
+			match += inc32table[offset];
+			memcpy(op + 4, match, 4);
+			match -= dec64table[offset];
+		} else {
+			LZ4_copy8(op, match);
+			match += 8;
+		}
+
+		op += 8;
+
+		if (unlikely(cpy > oend - MATCH_SAFEGUARD_DISTANCE)) {
+			BYTE * const oCopyLimit = oend - (WILDCOPYLENGTH - 1);
+
+			if (cpy > oend - LASTLITERALS) {
+				/*
+				 * Error : last LASTLITERALS bytes
+				 * must be literals (uncompressed)
+				 */
+				goto _output_error;
+			}
+
+			if (op < oCopyLimit) {
+				LZ4_wildCopy(op, match, oCopyLimit);
+				match += oCopyLimit - op;
+				op = oCopyLimit;
+			}
+			while (op < cpy)
+				*op++ = *match++;
+		} else {
+			LZ4_copy8(op, match);
+			if (length > 16)
+				LZ4_wildCopy(op + 8, match + 8, cpy);
+		}
+		op = cpy; /* wildcopy correction */
+	}
+
+	/* end of decoding */
+	if (endOnInput) {
+		/* Nb of output bytes decoded */
+		return (int) (((char *)op) - dst);
+	} else {
+		/* Nb of input bytes read */
+		return (int) (((const char *)ip) - src);
+	}
+
+	/* Overflow error detected */
+_output_error:
+	return (int) (-(((const char *)ip) - src)) - 1;
+}
+
+int LZ4_decompress_safe(const char *source, char *dest,
+	int compressedSize, int maxDecompressedSize)
+{
+	return LZ4_decompress_generic(source, dest,
+				      compressedSize, maxDecompressedSize,
+				      endOnInputSize, decode_full_block,
+				      noDict, (BYTE *)dest, NULL, 0);
+}
+
+int LZ4_decompress_safe_partial(const char *src, char *dst,
+	int compressedSize, int targetOutputSize, int dstCapacity)
+{
+	dstCapacity = min(targetOutputSize, dstCapacity);
+	return LZ4_decompress_generic(src, dst, compressedSize, dstCapacity,
+				      endOnInputSize, partial_decode,
+				      noDict, (BYTE *)dst, NULL, 0);
+}
diff --git a/fs/erofs/lz4.h b/fs/erofs/lz4.h
new file mode 100644
index 0000000000..0467a348e1
--- /dev/null
+++ b/fs/erofs/lz4.h
@@ -0,0 +1,5 @@
+/* SPDX-License-Identifier: GPL 2.0+ OR BSD-2-Clause */
+int LZ4_decompress_safe(const char *source, char *dest,
+	int compressedSize, int maxDecompressedSize);
+int LZ4_decompress_safe_partial(const char *src, char *dst,
+	int compressedSize, int targetOutputSize, int dstCapacity);
-- 
2.25.1


^ permalink raw reply	[flat|nested] 18+ messages in thread

* [PATCH v2 3/3] fs/erofs: add lz4 decompression support
  2021-08-23 12:36 ` [PATCH v2 0/3] " Huang Jianan
  2021-08-23 12:36   ` [PATCH v2 1/3] fs/erofs: add erofs filesystem support Huang Jianan
  2021-08-23 12:36   ` [PATCH v2 2/3] fs/erofs: add lz4 1.8.3 decompressor Huang Jianan
@ 2021-08-23 12:36   ` Huang Jianan
  2021-08-25  1:23   ` [PATCH v2 0/3] fs/erofs: new filesystem Gao Xiang
  2021-08-25 22:40   ` Tom Rini
  4 siblings, 0 replies; 18+ messages in thread
From: Huang Jianan @ 2021-08-23 12:36 UTC (permalink / raw)
  To: u-boot; +Cc: xiang, linux-erofs

From: Huang Jianan <huangjianan@oppo.com>

Support EROFS lz4 compressed files.

Signed-off-by: Huang Jianan <huangjianan@oppo.com>
---
 fs/erofs/Makefile     |   4 +-
 fs/erofs/data.c       |  84 ++++++-
 fs/erofs/decompress.c |  74 ++++++
 fs/erofs/decompress.h |  29 +++
 fs/erofs/namei.c      |   2 +-
 fs/erofs/zmap.c       | 517 ++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 707 insertions(+), 3 deletions(-)
 create mode 100644 fs/erofs/decompress.c
 create mode 100644 fs/erofs/decompress.h
 create mode 100644 fs/erofs/zmap.c

diff --git a/fs/erofs/Makefile b/fs/erofs/Makefile
index c4fc5b794e..8f1f99a096 100644
--- a/fs/erofs/Makefile
+++ b/fs/erofs/Makefile
@@ -5,4 +5,6 @@ obj-$(CONFIG_$(SPL_)FS_EROFS) = fs.o \
 				super.o \
 				namei.o \
 				data.o \
-				lz4.o
+				lz4.o \
+				decompress.o \
+				zmap.o
diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index a0f613264a..04ba9b5765 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0+
 #include "internal.h"
+#include "decompress.h"
 
 static int erofs_map_blocks_flatmode(struct erofs_inode *inode,
 				     struct erofs_map_blocks *map,
@@ -107,6 +108,87 @@ static int erofs_read_raw_data(struct erofs_inode *inode, char *buffer,
 	return 0;
 }
 
+static int z_erofs_read_data(struct erofs_inode *inode, char *buffer,
+			     erofs_off_t size, erofs_off_t offset)
+{
+	erofs_off_t end, length, skip;
+	struct erofs_map_blocks map = {
+		.index = UINT_MAX,
+	};
+	bool partial;
+	unsigned int algorithmformat, bufsize;
+	char *raw = NULL;
+	int ret = 0;
+
+	end = offset + size;
+	bufsize = 0;
+	while (end > offset) {
+		map.m_la = end - 1;
+
+		ret = z_erofs_map_blocks_iter(inode, &map);
+		if (ret)
+			break;
+
+		/*
+		 * trim to the needed size if the returned extent is quite
+		 * larger than requested, and set up partial flag as well.
+		 */
+		if (end < map.m_la + map.m_llen) {
+			length = end - map.m_la;
+			partial = true;
+		} else {
+			DBG_BUGON(end != map.m_la + map.m_llen);
+			length = map.m_llen;
+			partial = !(map.m_flags & EROFS_MAP_FULL_MAPPED);
+		}
+
+		if (map.m_la < offset) {
+			skip = offset - map.m_la;
+			end = offset;
+		} else {
+			skip = 0;
+			end = map.m_la;
+		}
+
+		if (!(map.m_flags & EROFS_MAP_MAPPED)) {
+			memset(buffer + end - offset, 0, length);
+			end = map.m_la;
+			continue;
+		}
+
+		if (map.m_plen > bufsize) {
+			bufsize = map.m_plen;
+			raw = realloc(raw, bufsize);
+			if (!raw) {
+				ret = -ENOMEM;
+				break;
+			}
+		}
+		ret = erofs_dev_read(raw, map.m_pa, map.m_plen);
+		if (ret < 0)
+			break;
+
+		algorithmformat = map.m_flags & EROFS_MAP_ZIPPED ?
+						Z_EROFS_COMPRESSION_LZ4 :
+						Z_EROFS_COMPRESSION_SHIFTED;
+
+		ret = z_erofs_decompress(&(struct z_erofs_decompress_req) {
+					.in = raw,
+					.out = buffer + end - offset,
+					.decodedskip = skip,
+					.inputsize = map.m_plen,
+					.decodedlength = length,
+					.alg = algorithmformat,
+					.partial_decoding = partial
+					 });
+		if (ret < 0)
+			break;
+	}
+	if (raw)
+		free(raw);
+	return ret < 0 ? ret : 0;
+}
+
 int erofs_pread(struct erofs_inode *inode, char *buf,
 		erofs_off_t count, erofs_off_t offset)
 {
@@ -116,7 +198,7 @@ int erofs_pread(struct erofs_inode *inode, char *buf,
 		return erofs_read_raw_data(inode, buf, count, offset);
 	case EROFS_INODE_FLAT_COMPRESSION_LEGACY:
 	case EROFS_INODE_FLAT_COMPRESSION:
-		return -EOPNOTSUPP;
+		return z_erofs_read_data(inode, buf, count, offset);
 	default:
 		break;
 	}
diff --git a/fs/erofs/decompress.c b/fs/erofs/decompress.c
new file mode 100644
index 0000000000..f960f6442a
--- /dev/null
+++ b/fs/erofs/decompress.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include "decompress.h"
+#include "lz4.h"
+
+static int z_erofs_decompress_lz4(struct z_erofs_decompress_req *rq)
+{
+	int ret = 0;
+	char *dest = rq->out;
+	char *src = rq->in;
+	char *buff = NULL;
+	bool support_0padding = false;
+	unsigned int inputmargin = 0;
+
+	if (erofs_sb_has_lz4_0padding()) {
+		support_0padding = true;
+
+		while (!src[inputmargin & ~PAGE_MASK])
+			if (!(++inputmargin & ~PAGE_MASK))
+				break;
+
+		if (inputmargin >= rq->inputsize)
+			return -EIO;
+	}
+
+	if (rq->decodedskip) {
+		buff = malloc(rq->decodedlength);
+		if (!buff)
+			return -ENOMEM;
+		dest = buff;
+	}
+
+	if (rq->partial_decoding || !support_0padding)
+		ret = LZ4_decompress_safe_partial(src + inputmargin, dest,
+				rq->inputsize - inputmargin,
+				rq->decodedlength, rq->decodedlength);
+	else
+		ret = LZ4_decompress_safe(src + inputmargin, dest,
+					  rq->inputsize - inputmargin,
+					  rq->decodedlength);
+
+	if (ret != (int)rq->decodedlength) {
+		ret = -EIO;
+		goto out;
+	}
+
+	if (rq->decodedskip)
+		memcpy(rq->out, dest + rq->decodedskip,
+		       rq->decodedlength - rq->decodedskip);
+
+out:
+	if (buff)
+		free(buff);
+
+	return ret;
+}
+
+int z_erofs_decompress(struct z_erofs_decompress_req *rq)
+{
+	if (rq->alg == Z_EROFS_COMPRESSION_SHIFTED) {
+		if (rq->inputsize != EROFS_BLKSIZ)
+			return -EFSCORRUPTED;
+
+		DBG_BUGON(rq->decodedlength > EROFS_BLKSIZ);
+		DBG_BUGON(rq->decodedlength < rq->decodedskip);
+
+		memcpy(rq->out, rq->in + rq->decodedskip,
+		       rq->decodedlength - rq->decodedskip);
+		return 0;
+	}
+
+	if (rq->alg == Z_EROFS_COMPRESSION_LZ4)
+		return z_erofs_decompress_lz4(rq);
+	return -EOPNOTSUPP;
+}
diff --git a/fs/erofs/decompress.h b/fs/erofs/decompress.h
new file mode 100644
index 0000000000..a12e11f386
--- /dev/null
+++ b/fs/erofs/decompress.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+#ifndef __EROFS_DECOMPRESS_H
+#define __EROFS_DECOMPRESS_H
+
+#include "internal.h"
+
+enum {
+	Z_EROFS_COMPRESSION_SHIFTED = Z_EROFS_COMPRESSION_MAX,
+	Z_EROFS_COMPRESSION_RUNTIME_MAX
+};
+
+struct z_erofs_decompress_req {
+	char *in, *out;
+
+	/*
+	 * initial decompressed bytes that need to be skipped
+	 * when finally copying to output buffer
+	 */
+	unsigned int decodedskip;
+	unsigned int inputsize, decodedlength;
+
+	/* indicate the algorithm will be used for decompression */
+	unsigned int alg;
+	bool partial_decoding;
+};
+
+int z_erofs_decompress(struct z_erofs_decompress_req *rq);
+
+#endif
diff --git a/fs/erofs/namei.c b/fs/erofs/namei.c
index 4c5d614483..7a0fbe2bc1 100644
--- a/fs/erofs/namei.c
+++ b/fs/erofs/namei.c
@@ -101,7 +101,7 @@ int erofs_read_inode_from_disk(struct erofs_inode *vi)
 
 	vi->flags = 0;
 	if (erofs_inode_is_data_compressed(vi->datalayout))
-		return -EOPNOTSUPP;
+		z_erofs_fill_inode(vi);
 	return 0;
 bogusimode:
 	erofs_err("bogus i_mode (%o) @ nid %llu", vi->i_mode, vi->nid | 0ULL);
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
new file mode 100644
index 0000000000..ff7f89f40c
--- /dev/null
+++ b/fs/erofs/zmap.c
@@ -0,0 +1,517 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include "internal.h"
+
+int z_erofs_fill_inode(struct erofs_inode *vi)
+{
+	if (!erofs_sb_has_big_pcluster() &&
+	    vi->datalayout == 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->flags |= EROFS_I_Z_INITED;
+	}
+	return 0;
+}
+
+static int z_erofs_fill_inode_lazy(struct erofs_inode *vi)
+{
+	int ret;
+	erofs_off_t pos;
+	struct z_erofs_map_header *h;
+	char buf[sizeof(struct z_erofs_map_header)];
+
+	if (vi->flags & EROFS_I_Z_INITED)
+		return 0;
+
+	DBG_BUGON(!erofs_sb_has_big_pcluster() &&
+		  vi->datalayout == EROFS_INODE_FLAT_COMPRESSION_LEGACY);
+	pos = round_up(iloc(vi->nid) + vi->inode_isize + vi->xattr_isize, 8);
+
+	ret = erofs_dev_read(buf, pos, sizeof(buf));
+	if (ret < 0)
+		return -EIO;
+
+	h = (struct z_erofs_map_header *)buf;
+	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) {
+		erofs_err("unknown compression format %u for nid %llu",
+			  vi->z_algorithmtype[0], (unsigned long long)vi->nid);
+		return -EOPNOTSUPP;
+	}
+
+	vi->z_logical_clusterbits = LOG_BLOCK_SIZE + (h->h_clusterbits & 7);
+	if (vi->datalayout == EROFS_INODE_FLAT_COMPRESSION &&
+	    !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1) ^
+	    !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_2)) {
+		erofs_err(
+"big pcluster head1/2 of compact indexes should be consistent for nid %llu",
+			  vi->nid * 1ULL);
+		return -EFSCORRUPTED;
+	}
+	vi->flags |= EROFS_I_Z_INITED;
+	return 0;
+}
+
+struct z_erofs_maprecorder {
+	struct erofs_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, compressedlcs;
+};
+
+static int z_erofs_reload_indexes(struct z_erofs_maprecorder *m,
+				  erofs_blk_t eblk)
+{
+	int ret;
+	struct erofs_map_blocks *const map = m->map;
+	char *mpage = map->mpage;
+
+	if (map->index == eblk)
+		return 0;
+
+	ret = erofs_blk_read(mpage, eblk, 1);
+	if (ret < 0)
+		return -EIO;
+
+	map->index = eblk;
+
+	return 0;
+}
+
+static int legacy_load_cluster_from_disk(struct z_erofs_maprecorder *m,
+					 unsigned long lcn)
+{
+	struct erofs_inode *const vi = m->inode;
+	const erofs_off_t ibase = iloc(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]);
+		if (m->delta[0] & Z_EROFS_VLE_DI_D0_CBLKCNT) {
+			if (!(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1)) {
+				DBG_BUGON(1);
+				return -EFSCORRUPTED;
+			}
+			m->compressedlcs = m->delta[0] &
+				~Z_EROFS_VLE_DI_D0_CBLKCNT;
+			m->delta[0] = 1;
+		}
+		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 -EOPNOTSUPP;
+	}
+	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_inode *const vi = 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;
+	bool big_pcluster;
+
+	if (1 << amortizedshift == 4)
+		vcnt = 2;
+	else if (1 << amortizedshift == 2 && lclusterbits == 12)
+		vcnt = 16;
+	else
+		return -EOPNOTSUPP;
+
+	big_pcluster = vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1;
+	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 (lo & Z_EROFS_VLE_DI_D0_CBLKCNT) {
+			if (!big_pcluster) {
+				DBG_BUGON(1);
+				return -EFSCORRUPTED;
+			}
+			m->compressedlcs = lo & ~Z_EROFS_VLE_DI_D0_CBLKCNT;
+			m->delta[0] = 1;
+			return 0;
+		} else if (i + 1 != (int)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;
+		else if (lo & Z_EROFS_VLE_DI_D0_CBLKCNT)
+			lo = 1;
+		m->delta[0] = lo + 1;
+		return 0;
+	}
+	m->clusterofs = lo;
+	m->delta[0] = 0;
+	/* figout out blkaddr (pblk) for HEAD lclusters */
+	if (!big_pcluster) {
+		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;
+		}
+	} else {
+		nblk = 0;
+		while (i > 0) {
+			--i;
+			lo = decode_compactedbits(lclusterbits, lomask,
+						  in, encodebits * i, &type);
+			if (type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD) {
+				if (lo & Z_EROFS_VLE_DI_D0_CBLKCNT) {
+					--i;
+					nblk += lo & ~Z_EROFS_VLE_DI_D0_CBLKCNT;
+					continue;
+				}
+				if (lo == 1) {
+					DBG_BUGON(1);
+					/* --i; ++nblk;	continue; */
+					return -EFSCORRUPTED;
+				}
+				i -= lo - 2;
+				continue;
+			}
+			++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 erofs_inode *const vi = m->inode;
+	const unsigned int lclusterbits = vi->z_logical_clusterbits;
+	const erofs_off_t ebase = round_up(iloc(vi->nid) + vi->inode_isize +
+					   vi->xattr_isize, 8) +
+		sizeof(struct z_erofs_map_header);
+	const unsigned int totalidx = DIV_ROUND_UP(vi->i_size, EROFS_BLKSIZ);
+	unsigned int compacted_4b_initial, compacted_2b;
+	unsigned int amortizedshift;
+	erofs_off_t pos;
+	int err;
+
+	if (lclusterbits != 12)
+		return -EOPNOTSUPP;
+
+	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 z_erofs_load_cluster_from_disk(struct z_erofs_maprecorder *m,
+					  unsigned int lcn)
+{
+	const unsigned int datamode = m->inode->datalayout;
+
+	if (datamode == EROFS_INODE_FLAT_COMPRESSION_LEGACY)
+		return 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 z_erofs_extent_lookback(struct z_erofs_maprecorder *m,
+				   unsigned int lookback_distance)
+{
+	struct erofs_inode *const vi = 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) {
+		erofs_err("bogus lookback distance @ nid %llu",
+			  (unsigned long long)vi->nid);
+		DBG_BUGON(1);
+		return -EFSCORRUPTED;
+	}
+
+	/* load extent head logical cluster if needed */
+	lcn -= lookback_distance;
+	err = z_erofs_load_cluster_from_disk(m, lcn);
+	if (err)
+		return err;
+
+	switch (m->type) {
+	case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
+		if (!m->delta[0]) {
+			erofs_err("invalid lookback distance 0 @ nid %llu",
+				  (unsigned long long)vi->nid);
+			DBG_BUGON(1);
+			return -EFSCORRUPTED;
+		}
+		return z_erofs_extent_lookback(m, m->delta[0]);
+	case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
+		map->m_flags &= ~EROFS_MAP_ZIPPED;
+	case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
+		map->m_la = (lcn << lclusterbits) | m->clusterofs;
+		break;
+	default:
+		erofs_err("unknown type %u @ lcn %lu of nid %llu",
+			  m->type, lcn, (unsigned long long)vi->nid);
+		DBG_BUGON(1);
+		return -EOPNOTSUPP;
+	}
+	return 0;
+}
+
+static int z_erofs_get_extent_compressedlen(struct z_erofs_maprecorder *m,
+					    unsigned int initial_lcn)
+{
+	struct erofs_inode *const vi = m->inode;
+	struct erofs_map_blocks *const map = m->map;
+	const unsigned int lclusterbits = vi->z_logical_clusterbits;
+	unsigned long lcn;
+	int err;
+
+	DBG_BUGON(m->type != Z_EROFS_VLE_CLUSTER_TYPE_PLAIN &&
+		  m->type != Z_EROFS_VLE_CLUSTER_TYPE_HEAD);
+	if (!(map->m_flags & EROFS_MAP_ZIPPED) ||
+	    !(vi->z_advise & Z_EROFS_ADVISE_BIG_PCLUSTER_1)) {
+		map->m_plen = 1 << lclusterbits;
+		return 0;
+	}
+
+	lcn = m->lcn + 1;
+	if (m->compressedlcs)
+		goto out;
+
+	err = z_erofs_load_cluster_from_disk(m, lcn);
+	if (err)
+		return err;
+
+	/*
+	 * If the 1st NONHEAD lcluster has already been handled initially w/o
+	 * valid compressedlcs, which means at least it mustn't be CBLKCNT, or
+	 * an internal implemenatation error is detected.
+	 *
+	 * The following code can also handle it properly anyway, but let's
+	 * BUG_ON in the debugging mode only for developers to notice that.
+	 */
+	DBG_BUGON(lcn == initial_lcn &&
+		  m->type == Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD);
+
+	switch (m->type) {
+	case Z_EROFS_VLE_CLUSTER_TYPE_PLAIN:
+	case Z_EROFS_VLE_CLUSTER_TYPE_HEAD:
+		/*
+		 * if the 1st NONHEAD lcluster is actually PLAIN or HEAD type
+		 * rather than CBLKCNT, it's a 1 lcluster-sized pcluster.
+		 */
+		m->compressedlcs = 1;
+		break;
+	case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
+		if (m->delta[0] != 1)
+			goto err_bonus_cblkcnt;
+		if (m->compressedlcs)
+			break;
+		/* fallthrough */
+	default:
+		erofs_err("cannot found CBLKCNT @ lcn %lu of nid %llu",
+			  lcn, vi->nid | 0ULL);
+		DBG_BUGON(1);
+		return -EFSCORRUPTED;
+	}
+out:
+	map->m_plen = m->compressedlcs << lclusterbits;
+	return 0;
+err_bonus_cblkcnt:
+	erofs_err("bogus CBLKCNT @ lcn %lu of nid %llu",
+		  lcn, vi->nid | 0ULL);
+	DBG_BUGON(1);
+	return -EFSCORRUPTED;
+}
+
+int z_erofs_map_blocks_iter(struct erofs_inode *vi,
+			    struct erofs_map_blocks *map)
+{
+	struct z_erofs_maprecorder m = {
+		.inode = vi,
+		.map = map,
+		.kaddr = map->mpage,
+	};
+	int err = 0;
+	unsigned int lclusterbits, endoff;
+	unsigned long initial_lcn;
+	unsigned long long ofs, end;
+
+	/* when trying to read beyond EOF, leave it unmapped */
+	if (map->m_la >= vi->i_size) {
+		map->m_llen = map->m_la + 1 - vi->i_size;
+		map->m_la = vi->i_size;
+		map->m_flags = 0;
+		goto out;
+	}
+
+	err = z_erofs_fill_inode_lazy(vi);
+	if (err)
+		goto out;
+
+	lclusterbits = vi->z_logical_clusterbits;
+	ofs = map->m_la;
+	initial_lcn = ofs >> lclusterbits;
+	endoff = ofs & ((1 << lclusterbits) - 1);
+
+	err = z_erofs_load_cluster_from_disk(&m, initial_lcn);
+	if (err)
+		goto 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;
+	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 (!m.lcn) {
+			erofs_err("invalid logical cluster 0 at nid %llu",
+				  (unsigned long long)vi->nid);
+			err = -EFSCORRUPTED;
+			goto out;
+		}
+		end = (m.lcn << lclusterbits) | m.clusterofs;
+		map->m_flags |= EROFS_MAP_FULL_MAPPED;
+		m.delta[0] = 1;
+	case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
+		/* get the correspoinding first chunk */
+		err = z_erofs_extent_lookback(&m, m.delta[0]);
+		if (err)
+			goto out;
+		break;
+	default:
+		erofs_err("unknown type %u @ offset %llu of nid %llu",
+			  m.type, ofs, (unsigned long long)vi->nid);
+		err = -EOPNOTSUPP;
+		goto out;
+	}
+
+	map->m_llen = end - map->m_la;
+	map->m_pa = blknr_to_addr(m.pblk);
+
+	err = z_erofs_get_extent_compressedlen(&m, initial_lcn);
+	if (err)
+		goto out;
+	map->m_flags |= EROFS_MAP_MAPPED;
+
+out:
+	erofs_dbg("m_la %" PRIu64 " m_pa %" PRIu64 " m_llen %" PRIu64 " m_plen %" PRIu64 " m_flags 0%o",
+		  map->m_la, map->m_pa,
+		  map->m_llen, map->m_plen, map->m_flags);
+
+	DBG_BUGON(err < 0 && err != -ENOMEM);
+	return err;
+}
-- 
2.25.1


^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [PATCH v2 0/3] fs/erofs: new filesystem
  2021-08-23 12:36 ` [PATCH v2 0/3] " Huang Jianan
                     ` (2 preceding siblings ...)
  2021-08-23 12:36   ` [PATCH v2 3/3] fs/erofs: add lz4 decompression support Huang Jianan
@ 2021-08-25  1:23   ` Gao Xiang
  2021-08-25 22:40   ` Tom Rini
  4 siblings, 0 replies; 18+ messages in thread
From: Gao Xiang @ 2021-08-25  1:23 UTC (permalink / raw)
  To: Huang Jianan; +Cc: u-boot, xiang, linux-erofs

Hi U-Boot folks, 

On Mon, Aug 23, 2021 at 08:36:43PM +0800, Huang Jianan wrote:
> From: Huang Jianan <huangjianan@oppo.com>
> 
> Add erofs filesystem support.
> 
> The code is adapted from erofs-utils in order to reduce maintenance
> burden and keep with the latest feature.
> 
> Changes since v1:
>  - fix the inconsistency between From and SoB (Bin Meng);
>  - add missing license header;
> 
> Huang Jianan (3):
>   fs/erofs: add erofs filesystem support
>   fs/erofs: add lz4 1.8.3 decompressor
>   fs/erofs: add lz4 decompression support

Could someone take some time looking into this? I think adding erofs
support to U-Boot is useful for booting with erofs. And keep sync
with erofsfuse code in erofs-utils is a good strategy for latest
feature.

Thanks in advance.

Thanks,
Gao Xiang

> 
>  fs/Kconfig            |   1 +
>  fs/Makefile           |   1 +
>  fs/erofs/Kconfig      |  12 +
>  fs/erofs/Makefile     |  10 +
>  fs/erofs/data.c       | 206 ++++++++++++++++
>  fs/erofs/decompress.c |  74 ++++++
>  fs/erofs/decompress.h |  29 +++
>  fs/erofs/erofs_fs.h   | 384 ++++++++++++++++++++++++++++++
>  fs/erofs/fs.c         | 231 ++++++++++++++++++
>  fs/erofs/internal.h   | 203 ++++++++++++++++
>  fs/erofs/lz4.c        | 534 ++++++++++++++++++++++++++++++++++++++++++
>  fs/erofs/lz4.h        |   5 +
>  fs/erofs/namei.c      | 238 +++++++++++++++++++
>  fs/erofs/super.c      |  65 +++++
>  fs/erofs/zmap.c       | 517 ++++++++++++++++++++++++++++++++++++++++
>  fs/fs.c               |  22 ++
>  include/erofs.h       |  19 ++
>  include/fs.h          |   1 +
>  18 files changed, 2552 insertions(+)
>  create mode 100644 fs/erofs/Kconfig
>  create mode 100644 fs/erofs/Makefile
>  create mode 100644 fs/erofs/data.c
>  create mode 100644 fs/erofs/decompress.c
>  create mode 100644 fs/erofs/decompress.h
>  create mode 100644 fs/erofs/erofs_fs.h
>  create mode 100644 fs/erofs/fs.c
>  create mode 100644 fs/erofs/internal.h
>  create mode 100644 fs/erofs/lz4.c
>  create mode 100644 fs/erofs/lz4.h
>  create mode 100644 fs/erofs/namei.c
>  create mode 100644 fs/erofs/super.c
>  create mode 100644 fs/erofs/zmap.c
>  create mode 100644 include/erofs.h
> 
> -- 
> 2.25.1

^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [PATCH v2 1/3] fs/erofs: add erofs filesystem support
  2021-08-23 12:36   ` [PATCH v2 1/3] fs/erofs: add erofs filesystem support Huang Jianan
@ 2021-08-25 22:39     ` Tom Rini
  2021-08-30 13:27       ` Huang Jianan
  0 siblings, 1 reply; 18+ messages in thread
From: Tom Rini @ 2021-08-25 22:39 UTC (permalink / raw)
  To: Huang Jianan; +Cc: u-boot, xiang, linux-erofs

[-- Attachment #1: Type: text/plain, Size: 1424 bytes --]

On Mon, Aug 23, 2021 at 08:36:44PM +0800, Huang Jianan wrote:

> From: Huang Jianan <huangjianan@oppo.com>
> 
> This patch mainly deals with uncompressed files.
> 
> Signed-off-by: Huang Jianan <huangjianan@oppo.com>
> ---
>  fs/Kconfig          |   1 +
>  fs/Makefile         |   1 +
>  fs/erofs/Kconfig    |  12 ++
>  fs/erofs/Makefile   |   7 +
>  fs/erofs/data.c     | 124 ++++++++++++++
>  fs/erofs/erofs_fs.h | 384 ++++++++++++++++++++++++++++++++++++++++++++
>  fs/erofs/fs.c       | 231 ++++++++++++++++++++++++++
>  fs/erofs/internal.h | 203 +++++++++++++++++++++++
>  fs/erofs/namei.c    | 238 +++++++++++++++++++++++++++
>  fs/erofs/super.c    |  65 ++++++++
>  fs/fs.c             |  22 +++
>  include/erofs.h     |  19 +++
>  include/fs.h        |   1 +
>  13 files changed, 1308 insertions(+)
>  create mode 100644 fs/erofs/Kconfig
>  create mode 100644 fs/erofs/Makefile
>  create mode 100644 fs/erofs/data.c
>  create mode 100644 fs/erofs/erofs_fs.h
>  create mode 100644 fs/erofs/fs.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 include/erofs.h

Do the style problems checkpatch.pl complains about here match what's in
the linux kernel?  I expect at lease some of them come from using custom
debug/etc macros rather than the standard logging functions.  Thanks.

-- 
Tom

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^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [PATCH v2 2/3] fs/erofs: add lz4 1.8.3 decompressor
  2021-08-23 12:36   ` [PATCH v2 2/3] fs/erofs: add lz4 1.8.3 decompressor Huang Jianan
@ 2021-08-25 22:39     ` Tom Rini
  2021-08-30 13:30       ` Huang Jianan
  0 siblings, 1 reply; 18+ messages in thread
From: Tom Rini @ 2021-08-25 22:39 UTC (permalink / raw)
  To: Huang Jianan; +Cc: u-boot, xiang, linux-erofs

[-- Attachment #1: Type: text/plain, Size: 671 bytes --]

On Mon, Aug 23, 2021 at 08:36:45PM +0800, Huang Jianan wrote:

> From: Huang Jianan <huangjianan@oppo.com>
> 
> In order to use the newest LZ4_decompress_safe_partial() which can
> now decode exactly the nb of bytes requested.
> 
> Signed-off-by: Huang Jianan <huangjianan@oppo.com>
> ---
>  fs/erofs/Makefile |   3 +-
>  fs/erofs/lz4.c    | 534 ++++++++++++++++++++++++++++++++++++++++++++++
>  fs/erofs/lz4.h    |   5 +
>  3 files changed, 541 insertions(+), 1 deletion(-)
>  create mode 100644 fs/erofs/lz4.c
>  create mode 100644 fs/erofs/lz4.h

Why not use the existing lz4 support, or if it needs updating for new
features, update it?

-- 
Tom

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^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [PATCH v2 0/3] fs/erofs: new filesystem
  2021-08-23 12:36 ` [PATCH v2 0/3] " Huang Jianan
                     ` (3 preceding siblings ...)
  2021-08-25  1:23   ` [PATCH v2 0/3] fs/erofs: new filesystem Gao Xiang
@ 2021-08-25 22:40   ` Tom Rini
  4 siblings, 0 replies; 18+ messages in thread
From: Tom Rini @ 2021-08-25 22:40 UTC (permalink / raw)
  To: Huang Jianan; +Cc: u-boot, xiang, linux-erofs

[-- Attachment #1: Type: text/plain, Size: 722 bytes --]

On Mon, Aug 23, 2021 at 08:36:43PM +0800, Huang Jianan wrote:

> From: Huang Jianan <huangjianan@oppo.com>
> 
> Add erofs filesystem support.
> 
> The code is adapted from erofs-utils in order to reduce maintenance
> burden and keep with the latest feature.
> 
> Changes since v1:
>  - fix the inconsistency between From and SoB (Bin Meng);
>  - add missing license header;
> 
> Huang Jianan (3):
>   fs/erofs: add erofs filesystem support
>   fs/erofs: add lz4 1.8.3 decompressor
>   fs/erofs: add lz4 decompression support

Aside from what I've just now sent, can you please extend the existing
py/tests/ to cover basic functionality here, ensure they run on sandbox
and in CI?  Thanks.

-- 
Tom

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^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [PATCH v2 1/3] fs/erofs: add erofs filesystem support
  2021-08-25 22:39     ` Tom Rini
@ 2021-08-30 13:27       ` Huang Jianan
  2021-08-30 15:31         ` Huang Jianan
  0 siblings, 1 reply; 18+ messages in thread
From: Huang Jianan @ 2021-08-30 13:27 UTC (permalink / raw)
  To: Tom Rini; +Cc: u-boot, xiang, linux-erofs



在 2021/8/26 6:39, Tom Rini 写道:
> On Mon, Aug 23, 2021 at 08:36:44PM +0800, Huang Jianan wrote:
>
>> From: Huang Jianan <huangjianan@oppo.com>
>>
>> This patch mainly deals with uncompressed files.
>>
>> Signed-off-by: Huang Jianan <huangjianan@oppo.com>
>> ---
>>   fs/Kconfig          |   1 +
>>   fs/Makefile         |   1 +
>>   fs/erofs/Kconfig    |  12 ++
>>   fs/erofs/Makefile   |   7 +
>>   fs/erofs/data.c     | 124 ++++++++++++++
>>   fs/erofs/erofs_fs.h | 384 ++++++++++++++++++++++++++++++++++++++++++++
>>   fs/erofs/fs.c       | 231 ++++++++++++++++++++++++++
>>   fs/erofs/internal.h | 203 +++++++++++++++++++++++
>>   fs/erofs/namei.c    | 238 +++++++++++++++++++++++++++
>>   fs/erofs/super.c    |  65 ++++++++
>>   fs/fs.c             |  22 +++
>>   include/erofs.h     |  19 +++
>>   include/fs.h        |   1 +
>>   13 files changed, 1308 insertions(+)
>>   create mode 100644 fs/erofs/Kconfig
>>   create mode 100644 fs/erofs/Makefile
>>   create mode 100644 fs/erofs/data.c
>>   create mode 100644 fs/erofs/erofs_fs.h
>>   create mode 100644 fs/erofs/fs.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 include/erofs.h
> Do the style problems checkpatch.pl complains about here match what's in
> the linux kernel?  I expect at lease some of them come from using custom
> debug/etc macros rather than the standard logging functions.  Thanks.

The code is mainly come from erofs-utils, thems it has the same problem, i
will fix it ASAP.

Thanks,
Jianan



^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [PATCH v2 2/3] fs/erofs: add lz4 1.8.3 decompressor
  2021-08-25 22:39     ` Tom Rini
@ 2021-08-30 13:30       ` Huang Jianan
  0 siblings, 0 replies; 18+ messages in thread
From: Huang Jianan @ 2021-08-30 13:30 UTC (permalink / raw)
  To: Tom Rini; +Cc: u-boot, xiang, linux-erofs

在 2021/8/26 6:39, Tom Rini 写道:
> On Mon, Aug 23, 2021 at 08:36:45PM +0800, Huang Jianan wrote:
>
>> From: Huang Jianan <huangjianan@oppo.com>
>>
>> In order to use the newest LZ4_decompress_safe_partial() which can
>> now decode exactly the nb of bytes requested.
>>
>> Signed-off-by: Huang Jianan <huangjianan@oppo.com>
>> ---
>>   fs/erofs/Makefile |   3 +-
>>   fs/erofs/lz4.c    | 534 ++++++++++++++++++++++++++++++++++++++++++++++
>>   fs/erofs/lz4.h    |   5 +
>>   3 files changed, 541 insertions(+), 1 deletion(-)
>>   create mode 100644 fs/erofs/lz4.c
>>   create mode 100644 fs/erofs/lz4.h
> Why not use the existing lz4 support, or if it needs updating for new
> features, update it?
erofs use lz4 partial decompress, this feature is fully supported after 
lz4 1.8.3,
I will try to upgrade the existing one.

Thanks,
Jianan


^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [PATCH v2 1/3] fs/erofs: add erofs filesystem support
  2021-08-30 13:27       ` Huang Jianan
@ 2021-08-30 15:31         ` Huang Jianan
  2021-08-30 16:06           ` Tom Rini
  0 siblings, 1 reply; 18+ messages in thread
From: Huang Jianan @ 2021-08-30 15:31 UTC (permalink / raw)
  To: Tom Rini; +Cc: u-boot, xiang, linux-erofs

在 2021/8/30 21:27, Huang Jianan 写道:
>
>
> 在 2021/8/26 6:39, Tom Rini 写道:
>> On Mon, Aug 23, 2021 at 08:36:44PM +0800, Huang Jianan wrote:
>>
>>> From: Huang Jianan <huangjianan@oppo.com>
>>>
>>> This patch mainly deals with uncompressed files.
>>>
>>> Signed-off-by: Huang Jianan <huangjianan@oppo.com>
>>> ---
>>>   fs/Kconfig          |   1 +
>>>   fs/Makefile         |   1 +
>>>   fs/erofs/Kconfig    |  12 ++
>>>   fs/erofs/Makefile   |   7 +
>>>   fs/erofs/data.c     | 124 ++++++++++++++
>>>   fs/erofs/erofs_fs.h | 384 
>>> ++++++++++++++++++++++++++++++++++++++++++++
>>>   fs/erofs/fs.c       | 231 ++++++++++++++++++++++++++
>>>   fs/erofs/internal.h | 203 +++++++++++++++++++++++
>>>   fs/erofs/namei.c    | 238 +++++++++++++++++++++++++++
>>>   fs/erofs/super.c    |  65 ++++++++
>>>   fs/fs.c             |  22 +++
>>>   include/erofs.h     |  19 +++
>>>   include/fs.h        |   1 +
>>>   13 files changed, 1308 insertions(+)
>>>   create mode 100644 fs/erofs/Kconfig
>>>   create mode 100644 fs/erofs/Makefile
>>>   create mode 100644 fs/erofs/data.c
>>>   create mode 100644 fs/erofs/erofs_fs.h
>>>   create mode 100644 fs/erofs/fs.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 include/erofs.h
>> Do the style problems checkpatch.pl complains about here match what's in
>> the linux kernel?  I expect at lease some of them come from using custom
>> debug/etc macros rather than the standard logging functions. Thanks.
>
> The code is mainly come from erofs-utils, thems it has the same 
> problem, i
> will fix it ASAP.
>
> Thanks,
> Jianan
>
I have checked checkpatch.pl complains, some need to be fixed, and some
come frome using custom macros. It seems that there are still some warnings
that are inconsistent with the linux kernel, such as :

WARNING: Use 'if (IS_ENABLED(CONFIG...))' instead of '#if or #ifdef' where
possible
#835: FILE: fs/erofs/fs.c:224:
+#ifdef CONFIG_LIB_UUID

WARNING: Possible switch case/default not preceded by break or fallthrough
comment
#763: FILE: fs/erofs/zmap.c:489:
+       case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:

erofs-utils is written according to the linux kernel coding style, I 
expect this
part can be consistent in order to reduce maintenance burden and keep
with the latest feature.


^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [PATCH v2 1/3] fs/erofs: add erofs filesystem support
  2021-08-30 15:31         ` Huang Jianan
@ 2021-08-30 16:06           ` Tom Rini
  2021-08-30 16:23             ` Gao Xiang
  0 siblings, 1 reply; 18+ messages in thread
From: Tom Rini @ 2021-08-30 16:06 UTC (permalink / raw)
  To: Huang Jianan; +Cc: u-boot, xiang, linux-erofs

[-- Attachment #1: Type: text/plain, Size: 2900 bytes --]

On Mon, Aug 30, 2021 at 11:31:28PM +0800, Huang Jianan wrote:
> 在 2021/8/30 21:27, Huang Jianan 写道:
> > 
> > 
> > 在 2021/8/26 6:39, Tom Rini 写道:
> > > On Mon, Aug 23, 2021 at 08:36:44PM +0800, Huang Jianan wrote:
> > > 
> > > > From: Huang Jianan <huangjianan@oppo.com>
> > > > 
> > > > This patch mainly deals with uncompressed files.
> > > > 
> > > > Signed-off-by: Huang Jianan <huangjianan@oppo.com>
> > > > ---
> > > >   fs/Kconfig          |   1 +
> > > >   fs/Makefile         |   1 +
> > > >   fs/erofs/Kconfig    |  12 ++
> > > >   fs/erofs/Makefile   |   7 +
> > > >   fs/erofs/data.c     | 124 ++++++++++++++
> > > >   fs/erofs/erofs_fs.h | 384
> > > > ++++++++++++++++++++++++++++++++++++++++++++
> > > >   fs/erofs/fs.c       | 231 ++++++++++++++++++++++++++
> > > >   fs/erofs/internal.h | 203 +++++++++++++++++++++++
> > > >   fs/erofs/namei.c    | 238 +++++++++++++++++++++++++++
> > > >   fs/erofs/super.c    |  65 ++++++++
> > > >   fs/fs.c             |  22 +++
> > > >   include/erofs.h     |  19 +++
> > > >   include/fs.h        |   1 +
> > > >   13 files changed, 1308 insertions(+)
> > > >   create mode 100644 fs/erofs/Kconfig
> > > >   create mode 100644 fs/erofs/Makefile
> > > >   create mode 100644 fs/erofs/data.c
> > > >   create mode 100644 fs/erofs/erofs_fs.h
> > > >   create mode 100644 fs/erofs/fs.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 include/erofs.h
> > > Do the style problems checkpatch.pl complains about here match what's in
> > > the linux kernel?  I expect at lease some of them come from using custom
> > > debug/etc macros rather than the standard logging functions. Thanks.
> > 
> > The code is mainly come from erofs-utils, thems it has the same problem,
> > i
> > will fix it ASAP.
> > 
> > Thanks,
> > Jianan
> > 
> I have checked checkpatch.pl complains, some need to be fixed, and some
> come frome using custom macros. It seems that there are still some warnings
> that are inconsistent with the linux kernel, such as :
> 
> WARNING: Use 'if (IS_ENABLED(CONFIG...))' instead of '#if or #ifdef' where
> possible
> #835: FILE: fs/erofs/fs.c:224:
> +#ifdef CONFIG_LIB_UUID
> 
> WARNING: Possible switch case/default not preceded by break or fallthrough
> comment
> #763: FILE: fs/erofs/zmap.c:489:
> +       case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
> 
> erofs-utils is written according to the linux kernel coding style, I expect
> this
> part can be consistent in order to reduce maintenance burden and keep
> with the latest feature.

Yes, please fix what can be easily fixed and still kept in sync with
other projects.

-- 
Tom

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^ permalink raw reply	[flat|nested] 18+ messages in thread

* Re: [PATCH v2 1/3] fs/erofs: add erofs filesystem support
  2021-08-30 16:06           ` Tom Rini
@ 2021-08-30 16:23             ` Gao Xiang
  0 siblings, 0 replies; 18+ messages in thread
From: Gao Xiang @ 2021-08-30 16:23 UTC (permalink / raw)
  To: Tom Rini; +Cc: u-boot, xiang, linux-erofs

On Mon, Aug 30, 2021 at 12:06:46PM -0400, Tom Rini wrote:
> On Mon, Aug 30, 2021 at 11:31:28PM +0800, Huang Jianan wrote:
> > 在 2021/8/30 21:27, Huang Jianan 写道:
> > > 
> > > 
> > > 在 2021/8/26 6:39, Tom Rini 写道:
> > > > On Mon, Aug 23, 2021 at 08:36:44PM +0800, Huang Jianan wrote:
> > > > 
> > > > > From: Huang Jianan <huangjianan@oppo.com>
> > > > > 
> > > > > This patch mainly deals with uncompressed files.
> > > > > 
> > > > > Signed-off-by: Huang Jianan <huangjianan@oppo.com>
> > > > > ---
> > > > >   fs/Kconfig          |   1 +
> > > > >   fs/Makefile         |   1 +
> > > > >   fs/erofs/Kconfig    |  12 ++
> > > > >   fs/erofs/Makefile   |   7 +
> > > > >   fs/erofs/data.c     | 124 ++++++++++++++
> > > > >   fs/erofs/erofs_fs.h | 384
> > > > > ++++++++++++++++++++++++++++++++++++++++++++
> > > > >   fs/erofs/fs.c       | 231 ++++++++++++++++++++++++++
> > > > >   fs/erofs/internal.h | 203 +++++++++++++++++++++++
> > > > >   fs/erofs/namei.c    | 238 +++++++++++++++++++++++++++
> > > > >   fs/erofs/super.c    |  65 ++++++++
> > > > >   fs/fs.c             |  22 +++
> > > > >   include/erofs.h     |  19 +++
> > > > >   include/fs.h        |   1 +
> > > > >   13 files changed, 1308 insertions(+)
> > > > >   create mode 100644 fs/erofs/Kconfig
> > > > >   create mode 100644 fs/erofs/Makefile
> > > > >   create mode 100644 fs/erofs/data.c
> > > > >   create mode 100644 fs/erofs/erofs_fs.h
> > > > >   create mode 100644 fs/erofs/fs.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 include/erofs.h
> > > > Do the style problems checkpatch.pl complains about here match what's in
> > > > the linux kernel?  I expect at lease some of them come from using custom
> > > > debug/etc macros rather than the standard logging functions. Thanks.
> > > 
> > > The code is mainly come from erofs-utils, thems it has the same problem,
> > > i
> > > will fix it ASAP.
> > > 
> > > Thanks,
> > > Jianan
> > > 
> > I have checked checkpatch.pl complains, some need to be fixed, and some
> > come frome using custom macros. It seems that there are still some warnings
> > that are inconsistent with the linux kernel, such as :
> > 
> > WARNING: Use 'if (IS_ENABLED(CONFIG...))' instead of '#if or #ifdef' where
> > possible
> > #835: FILE: fs/erofs/fs.c:224:
> > +#ifdef CONFIG_LIB_UUID
> > 
> > WARNING: Possible switch case/default not preceded by break or fallthrough
> > comment
> > #763: FILE: fs/erofs/zmap.c:489:
> > +       case Z_EROFS_VLE_CLUSTER_TYPE_NONHEAD:
> > 
> > erofs-utils is written according to the linux kernel coding style, I expect
> > this
> > part can be consistent in order to reduce maintenance burden and keep
> > with the latest feature.
> 
> Yes, please fix what can be easily fixed and still kept in sync with
> other projects.

Agreed, erofs-utils follows linux kernel style. Maybe we could fix both
together if easily fixed...

Thanks,
Gao Xiang

> 
> -- 
> Tom



^ permalink raw reply	[flat|nested] 18+ messages in thread

end of thread, other threads:[~2021-08-30 16:23 UTC | newest]

Thread overview: 18+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-08-22 15:48 [PATCH 1/3] fs/erofs: new filesystem Huang Jianan
2021-08-22 15:48 ` [PATCH 2/3] fs/erofs: add lz4 1.8.3 decompressor Huang Jianan
2021-08-22 15:48 ` [PATCH 3/3] fs/erofs: add lz4 decompression support Huang Jianan
2021-08-23  4:24 ` [PATCH 1/3] fs/erofs: new filesystem Bin Meng
2021-08-23 11:46   ` Huang Jianan
2021-08-23 12:36 ` [PATCH v2 0/3] " Huang Jianan
2021-08-23 12:36   ` [PATCH v2 1/3] fs/erofs: add erofs filesystem support Huang Jianan
2021-08-25 22:39     ` Tom Rini
2021-08-30 13:27       ` Huang Jianan
2021-08-30 15:31         ` Huang Jianan
2021-08-30 16:06           ` Tom Rini
2021-08-30 16:23             ` Gao Xiang
2021-08-23 12:36   ` [PATCH v2 2/3] fs/erofs: add lz4 1.8.3 decompressor Huang Jianan
2021-08-25 22:39     ` Tom Rini
2021-08-30 13:30       ` Huang Jianan
2021-08-23 12:36   ` [PATCH v2 3/3] fs/erofs: add lz4 decompression support Huang Jianan
2021-08-25  1:23   ` [PATCH v2 0/3] fs/erofs: new filesystem Gao Xiang
2021-08-25 22:40   ` Tom Rini

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