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From: Gao Xiang <gaoxiang25@huawei.com>
To: Chao Yu <yuchao0@huawei.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Christoph Hellwig <hch@lst.de>, <devel@driverdev.osuosl.org>
Cc: <linux-fsdevel@vger.kernel.org>, <linux-erofs@lists.ozlabs.org>,
	Chao Yu <chao@kernel.org>, Miao Xie <miaoxie@huawei.com>,
	Gao Xiang <gaoxiang25@huawei.com>
Subject: [PATCH v2 12/25] erofs: better erofs symlink stuffs
Date: Wed, 4 Sep 2019 10:08:59 +0800
Message-ID: <20190904020912.63925-13-gaoxiang25@huawei.com> (raw)
In-Reply-To: <20190904020912.63925-1-gaoxiang25@huawei.com>

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

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

[1] https://lore.kernel.org/r/20190830163910.GB29603@infradead.org/
[2] https://lore.kernel.org/r/20190829102426.GE20598@infradead.org/
Reported-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
---
 fs/erofs/inode.c    | 68 ++++++++++++++++++---------------------------
 fs/erofs/internal.h | 10 -------
 fs/erofs/super.c    |  5 ++--
 3 files changed, 29 insertions(+), 54 deletions(-)

diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index a42f5fc14df9..770f3259c862 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -127,50 +127,39 @@ static int read_inode(struct inode *inode, void *data)
 	return -EFSCORRUPTED;
 }
 
-/*
- * try_lock can be required since locking order is:
- *   file data(fs_inode)
- *        meta(bd_inode)
- * but the majority of the callers is "iget",
- * in that case we are pretty sure no deadlock since
- * no data operations exist. However I tend to
- * try_lock since it takes no much overhead and
- * will success immediately.
- */
-static int fill_inline_data(struct inode *inode, void *data,
-			    unsigned int m_pofs)
+static int erofs_fill_symlink(struct inode *inode, void *data,
+			      unsigned int m_pofs)
 {
 	struct erofs_inode *vi = EROFS_I(inode);
 	struct erofs_sb_info *sbi = EROFS_I_SB(inode);
+	char *lnk;
 
-	/* should be tail-packing data inline */
-	if (vi->datalayout != EROFS_INODE_FLAT_INLINE)
+	/* if it cannot be handled with fast symlink scheme */
+	if (vi->datalayout != EROFS_INODE_FLAT_INLINE ||
+	    inode->i_size >= PAGE_SIZE) {
+		inode->i_op = &erofs_symlink_iops;
 		return 0;
+	}
 
-	/* fast symlink */
-	if (S_ISLNK(inode->i_mode) && inode->i_size < PAGE_SIZE) {
-		char *lnk = erofs_kmalloc(sbi, inode->i_size + 1, GFP_KERNEL);
-
-		if (!lnk)
-			return -ENOMEM;
-
-		m_pofs += vi->inode_isize + vi->xattr_isize;
+	lnk = erofs_kmalloc(sbi, inode->i_size + 1, GFP_KERNEL);
+	if (!lnk)
+		return -ENOMEM;
 
-		/* inline symlink data shouldn't cross page boundary as well */
-		if (m_pofs + inode->i_size > PAGE_SIZE) {
-			kfree(lnk);
-			errln("inline data cross block boundary @ nid %llu",
-			      vi->nid);
-			DBG_BUGON(1);
-			return -EFSCORRUPTED;
-		}
+	m_pofs += vi->inode_isize + vi->xattr_isize;
+	/* inline symlink data shouldn't cross page boundary as well */
+	if (m_pofs + inode->i_size > PAGE_SIZE) {
+		kfree(lnk);
+		errln("inline data cross block boundary @ nid %llu",
+		      vi->nid);
+		DBG_BUGON(1);
+		return -EFSCORRUPTED;
+	}
 
-		memcpy(lnk, data + m_pofs, inode->i_size);
-		lnk[inode->i_size] = '\0';
+	memcpy(lnk, data + m_pofs, inode->i_size);
+	lnk[inode->i_size] = '\0';
 
-		inode->i_link = lnk;
-		set_inode_fast_symlink(inode);
-	}
+	inode->i_link = lnk;
+	inode->i_op = &erofs_fast_symlink_iops;
 	return 0;
 }
 
@@ -217,8 +206,9 @@ static int fill_inode(struct inode *inode, int isdir)
 			inode->i_fop = &erofs_dir_fops;
 			break;
 		case S_IFLNK:
-			/* by default, page_get_link is used for symlink */
-			inode->i_op = &erofs_symlink_iops;
+			err = erofs_fill_symlink(inode, data, ofs);
+			if (err)
+				goto out_unlock;
 			inode_nohighmem(inode);
 			break;
 		case S_IFCHR:
@@ -237,11 +227,7 @@ static int fill_inode(struct inode *inode, int isdir)
 			err = z_erofs_fill_inode(inode);
 			goto out_unlock;
 		}
-
 		inode->i_mapping->a_ops = &erofs_raw_access_aops;
-
-		/* fill last page if inline data is available */
-		err = fill_inline_data(inode, data, ofs);
 	}
 
 out_unlock:
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 10497ee07cae..cc1ea98c5c89 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -479,16 +479,6 @@ extern const struct inode_operations erofs_generic_iops;
 extern const struct inode_operations erofs_symlink_iops;
 extern const struct inode_operations erofs_fast_symlink_iops;
 
-static inline void set_inode_fast_symlink(struct inode *inode)
-{
-	inode->i_op = &erofs_fast_symlink_iops;
-}
-
-static inline bool is_inode_fast_symlink(struct inode *inode)
-{
-	return inode->i_op == &erofs_fast_symlink_iops;
-}
-
 struct inode *erofs_iget(struct super_block *sb, erofs_nid_t nid, bool dir);
 int erofs_getattr(const struct path *path, struct kstat *stat,
 		  u32 request_mask, unsigned int query_flags);
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 3986be582dbb..b8b0e35f6621 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -40,10 +40,9 @@ static void free_inode(struct inode *inode)
 {
 	struct erofs_inode *vi = EROFS_I(inode);
 
-	/* be careful RCU symlink path (see ext4_inode_info->i_data)! */
-	if (is_inode_fast_symlink(inode))
+	/* be careful of RCU symlink path */
+	if (inode->i_op == &erofs_fast_symlink_iops)
 		kfree(inode->i_link);
-
 	kfree(vi->xattr_shared_xattrs);
 
 	kmem_cache_free(erofs_inode_cachep, vi);
-- 
2.17.1


  parent reply index

Thread overview: 159+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-02 12:53 [PATCH v6 00/24] erofs: promote erofs from staging Gao Xiang
2019-08-02 12:53 ` [PATCH v6 01/24] erofs: add on-disk layout Gao Xiang
2019-08-29  9:59   ` Christoph Hellwig
2019-08-29 10:32     ` Gao Xiang
2019-08-29 10:36       ` Christoph Hellwig
2019-08-29 10:58         ` Gao Xiang
2019-08-29 15:58       ` Joe Perches
2019-08-29 17:26         ` Gao Xiang
2019-08-30 12:07         ` David Sterba
2019-08-30 12:18           ` Gao Xiang
2019-09-02  8:43           ` Pavel Machek
2019-09-02 14:07             ` David Sterba
2019-09-03 11:27               ` Pavel Machek
2019-08-29 15:41     ` Gao Xiang
2019-09-01  7:54     ` Gao Xiang
2019-09-02 12:45       ` Christoph Hellwig
2019-09-02 13:02         ` Gao Xiang
2019-09-02  8:40     ` Pavel Machek
2019-09-02 10:35       ` Gao Xiang
2019-08-02 12:53 ` [PATCH v6 02/24] erofs: add erofs in-memory stuffs Gao Xiang
2019-08-02 12:53 ` [PATCH v6 03/24] erofs: add super block operations Gao Xiang
2019-08-29 10:15   ` Christoph Hellwig
2019-08-29 10:50     ` Gao Xiang
2019-08-30 16:39       ` Christoph Hellwig
2019-08-30 17:15         ` Gao Xiang
2019-08-31  0:54           ` Gao Xiang
2019-08-31  6:34           ` Amir Goldstein
2019-08-31  6:48             ` Gao Xiang
2019-09-01  8:54     ` Gao Xiang
2019-09-02 12:51       ` Christoph Hellwig
2019-09-02 14:43         ` Gao Xiang
2019-09-02 15:19           ` Christoph Hellwig
2019-09-02 15:24             ` Gao Xiang
2019-08-02 12:53 ` [PATCH v6 04/24] erofs: add raw address_space operations Gao Xiang
2019-08-29 10:17   ` Christoph Hellwig
2019-08-29 11:46     ` Gao Xiang
2019-08-30 16:40       ` Christoph Hellwig
2019-08-30 17:23         ` Gao Xiang
2019-08-02 12:53 ` [PATCH v6 05/24] erofs: add inode operations Gao Xiang
2019-08-29 10:24   ` Christoph Hellwig
2019-08-29 11:59     ` Gao Xiang
2019-08-30 16:42       ` Christoph Hellwig
2019-08-30 18:46         ` Gao Xiang
2019-09-01  9:34     ` Gao Xiang
2019-09-02 12:53       ` Christoph Hellwig
2019-09-02 13:43       ` David Sterba
2019-09-02 13:55         ` Gao Xiang
2019-08-02 12:53 ` [PATCH v6 06/24] erofs: support special inode Gao Xiang
2019-08-29 10:25   ` Christoph Hellwig
2019-09-01  9:39     ` Gao Xiang
2019-08-02 12:53 ` [PATCH v6 07/24] erofs: add directory operations Gao Xiang
2019-08-02 12:53 ` [PATCH v6 08/24] erofs: add namei functions Gao Xiang
2019-08-29 10:28   ` Christoph Hellwig
2019-08-29 11:28     ` Gao Xiang
2019-08-02 12:53 ` [PATCH v6 09/24] erofs: support tracepoint Gao Xiang
2019-08-02 12:53 ` [PATCH v6 10/24] erofs: update Kconfig and Makefile Gao Xiang
2019-08-02 12:53 ` [PATCH v6 11/24] erofs: introduce xattr & posixacl support Gao Xiang
2019-08-02 12:53 ` [PATCH v6 12/24] erofs: introduce tagged pointer Gao Xiang
2019-08-02 12:53 ` [PATCH v6 13/24] erofs: add compression indexes support Gao Xiang
2019-08-02 12:53 ` [PATCH v6 14/24] erofs: introduce superblock registration Gao Xiang
2019-08-02 12:53 ` [PATCH v6 15/24] erofs: introduce erofs shrinker Gao Xiang
2019-08-02 12:53 ` [PATCH v6 16/24] erofs: introduce workstation for decompression Gao Xiang
2019-08-02 12:53 ` [PATCH v6 17/24] erofs: introduce per-CPU buffers implementation Gao Xiang
2019-08-02 12:53 ` [PATCH v6 18/24] erofs: introduce pagevec for decompression subsystem Gao Xiang
2019-08-02 12:53 ` [PATCH v6 19/24] erofs: add erofs_allocpage() Gao Xiang
2019-08-02 12:53 ` [PATCH v6 20/24] erofs: introduce generic decompression backend Gao Xiang
2019-08-02 12:53 ` [PATCH v6 21/24] erofs: introduce LZ4 decompression inplace Gao Xiang
2019-08-02 12:53 ` [PATCH v6 22/24] erofs: introduce the decompression frontend Gao Xiang
2019-08-02 12:53 ` [PATCH v6 23/24] erofs: introduce cached decompression Gao Xiang
2019-08-02 12:53 ` [PATCH v6 24/24] erofs: add document Gao Xiang
2019-09-01  5:51 ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Gao Xiang
2019-09-01  5:51   ` [PATCH 01/21] erofs: remove all the byte offset comments Gao Xiang
2019-09-02 12:05     ` Christoph Hellwig
2019-09-01  5:51   ` [PATCH 02/21] erofs: on-disk format should have explicitly assigned numbers Gao Xiang
2019-09-02 12:05     ` Christoph Hellwig
2019-09-01  5:51   ` [PATCH 03/21] erofs: some macros are much more readable as a function Gao Xiang
2019-09-02 12:06     ` Christoph Hellwig
2019-09-01  5:51   ` [PATCH 04/21] erofs: kill __packed for on-disk structures Gao Xiang
2019-09-02 12:06     ` Christoph Hellwig
2019-09-01  5:51   ` [PATCH 05/21] erofs: update erofs_inode_is_data_compressed helper Gao Xiang
2019-09-02 12:07     ` Christoph Hellwig
2019-09-01  5:51   ` [PATCH 06/21] erofs: kill erofs_{init,exit}_inode_cache Gao Xiang
2019-09-02 12:09     ` Christoph Hellwig
2019-09-01  5:51   ` [PATCH 07/21] erofs: use erofs_inode naming Gao Xiang
2019-09-02 12:10     ` Christoph Hellwig
2019-09-02 12:13       ` Gao Xiang
2019-09-02 12:47         ` Christoph Hellwig
2019-09-02 13:33           ` Gao Xiang
2019-09-01  5:51   ` [PATCH 08/21] erofs: update comments in inode.c Gao Xiang
2019-09-01  5:51   ` [PATCH 09/21] erofs: update erofs symlink stuffs Gao Xiang
2019-09-02 12:11     ` Christoph Hellwig
2019-09-01  5:51   ` [PATCH 10/21] erofs: kill is_inode_layout_compression() Gao Xiang
2019-09-02 12:11     ` Christoph Hellwig
2019-09-01  5:51   ` [PATCH 11/21] erofs: use dsb instead of layout for ondisk super_block Gao Xiang
2019-09-02 12:12     ` Christoph Hellwig
2019-09-02 12:15       ` Gao Xiang
2019-09-01  5:51   ` [PATCH 12/21] erofs: kill verbose debug info in erofs_fill_super Gao Xiang
2019-09-02 12:14     ` Christoph Hellwig
2019-09-02 12:18       ` Gao Xiang
2019-09-01  5:51   ` [PATCH 13/21] erofs: simplify erofs_grab_bio() since bio_alloc() never fail Gao Xiang
2019-09-02 12:20     ` Christoph Hellwig
2019-09-01  5:51   ` [PATCH 14/21] erofs: kill prio and nofail of erofs_get_meta_page() Gao Xiang
2019-09-02 12:21     ` Christoph Hellwig
2019-09-01  5:51   ` [PATCH 15/21] erofs: kill __submit_bio() Gao Xiang
2019-09-01  5:51   ` [PATCH 16/21] erofs: kill magic underscores Gao Xiang
2019-09-02 12:26     ` Christoph Hellwig
2019-09-02 12:39       ` Gao Xiang
2019-09-02 12:54         ` Christoph Hellwig
2019-09-02 13:38           ` Gao Xiang
2019-09-01  5:51   ` [PATCH 17/21] erofs: use a switch statement when dealing with the file modes Gao Xiang
2019-09-02 12:27     ` Christoph Hellwig
2019-09-01  5:51   ` [PATCH 18/21] erofs: add "erofs_" prefix for common and short functions Gao Xiang
2019-09-02 12:28     ` Christoph Hellwig
2019-09-01  5:51   ` [PATCH 19/21] erofs: kill all erofs specific fault injection Gao Xiang
2019-09-02 12:28     ` Christoph Hellwig
2019-09-01  5:51   ` [PATCH 20/21] erofs: kill use_vmap module parameter Gao Xiang
2019-09-02 12:31     ` Christoph Hellwig
2019-09-02 12:43       ` Gao Xiang
2019-09-01  5:51   ` [PATCH 21/21] erofs: save one level of indentation Gao Xiang
2019-09-02 12:31     ` Christoph Hellwig
2019-09-02 12:46   ` [PATCH 00/21] erofs: patchset addressing Christoph's comments Christoph Hellwig
2019-09-02 14:24     ` Gao Xiang
2019-09-02 15:23       ` Christoph Hellwig
2019-09-02 15:50         ` Gao Xiang
2019-09-03  6:58           ` Christoph Hellwig
2019-09-03  8:17             ` Gao Xiang
2019-09-03 15:37               ` Christoph Hellwig
2019-09-03 15:43                 ` Gao Xiang
2019-09-04  2:08   ` [PATCH v2 00/25] " Gao Xiang
2019-09-04  2:08     ` [PATCH v2 01/25] erofs: remove all the byte offset comments Gao Xiang
2019-09-04  2:08     ` [PATCH v2 02/25] erofs: on-disk format should have explicitly assigned numbers Gao Xiang
2019-09-04  2:08     ` [PATCH v2 03/25] erofs: some macros are much more readable as a function Gao Xiang
2019-09-04  2:08     ` [PATCH v2 04/25] erofs: kill __packed for on-disk structures Gao Xiang
2019-09-04  2:08     ` [PATCH v2 05/25] erofs: update erofs_inode_is_data_compressed helper Gao Xiang
2019-09-04  2:08     ` [PATCH v2 06/25] erofs: use feature_incompat rather than requirements Gao Xiang
2019-09-04  2:08     ` [PATCH v2 07/25] erofs: better naming for erofs inode related stuffs Gao Xiang
2019-09-04  2:08     ` [PATCH v2 08/25] erofs: kill erofs_{init,exit}_inode_cache Gao Xiang
2019-09-04  2:08     ` [PATCH v2 09/25] erofs: use erofs_inode naming Gao Xiang
2019-09-04  2:08     ` [PATCH v2 10/25] erofs: update erofs_fs.h comments Gao Xiang
2019-09-04  2:08     ` [PATCH v2 11/25] erofs: update comments in inode.c Gao Xiang
2019-09-04  2:08     ` Gao Xiang [this message]
2019-09-04  2:09     ` [PATCH v2 13/25] erofs: use dsb instead of layout for ondisk super_block Gao Xiang
2019-09-04  2:09     ` [PATCH v2 14/25] erofs: kill verbose debug info in erofs_fill_super Gao Xiang
2019-09-04  2:09     ` [PATCH v2 15/25] erofs: localize erofs_grab_bio() Gao Xiang
2019-09-04  2:09     ` [PATCH v2 16/25] erofs: kill prio and nofail of erofs_get_meta_page() Gao Xiang
2019-09-04  2:09     ` [PATCH v2 17/25] erofs: kill __submit_bio() Gao Xiang
2019-09-04  2:09     ` [PATCH v2 18/25] erofs: add "erofs_" prefix for common and short functions Gao Xiang
2019-09-04  2:09     ` [PATCH v2 19/25] erofs: kill all erofs specific fault injection Gao Xiang
2019-09-04  2:09     ` [PATCH v2 20/25] erofs: kill use_vmap module parameter Gao Xiang
2019-09-04  2:09     ` [PATCH v2 21/25] erofs: save one level of indentation Gao Xiang
2019-09-04  2:09     ` [PATCH v2 22/25] erofs: rename errln/infoln/debugln to erofs_{err,info,dbg} Gao Xiang
2019-09-04  2:09     ` [PATCH v2 23/25] erofs: use read_mapping_page instead of sb_bread Gao Xiang
2019-09-04  2:09     ` [PATCH v2 24/25] erofs: always use iget5_locked Gao Xiang
2019-09-04  2:09     ` [PATCH v2 25/25] erofs: use read_cache_page_gfp for erofs_get_meta_page Gao Xiang
2019-09-04  3:27     ` [PATCH v2 00/25] erofs: patchset addressing Christoph's comments Chao Yu
2019-09-05  1:03       ` Gao Xiang
2019-09-05 11:30         ` Christoph Hellwig
2019-09-04  5:16     ` Christoph Hellwig
2019-09-04  6:08       ` Gao Xiang

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