linux-kernel - [PATCH] f2fs: fix to keep backward compatibility of flexible inline xattr feature

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Date:   Wed, 25 Oct 2017 18:31:24 +0800
From:   Chao Yu <yuchao0@...wei.com>
To:     <jaegeuk@...nel.org>
CC:     <linux-f2fs-devel@...ts.sourceforge.net>,
        <linux-kernel@...r.kernel.org>, <chao@...nel.org>,
        Chao Yu <yuchao0@...wei.com>
Subject: [PATCH] f2fs: fix to keep backward compatibility of flexible inline xattr feature

Previously, in inode layout, we will always reserve 200 bytes for inline
xattr space no matter the inode enables inline xattr feature or not, due
to this reason, max inline size of inode is fixed, but now, if inline
xattr is not enabled, max inline size of inode will be enlarged by 200
bytes, for regular and symlink inode, it will be safe to reuse resevered
space as they are all zero, but for directory, we need to keep the
reservation for stablizing directory structure.

Reported-by: Sheng Yong <shengyong1@...wei.com>
Signed-off-by: Chao Yu <yuchao0@...wei.com>
---
 fs/f2fs/f2fs.h  |  5 +----
 fs/f2fs/inode.c | 15 ++++++++++++---
 fs/f2fs/namei.c |  2 ++
 3 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 2af1d31ae74b..7ddd0d085e3b 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -2393,10 +2393,7 @@ static inline int get_extra_isize(struct inode *inode)
 static inline int f2fs_sb_has_flexible_inline_xattr(struct super_block *sb);
 static inline int get_inline_xattr_addrs(struct inode *inode)
 {
-	if (!f2fs_has_inline_xattr(inode))
-		return 0;
-	if (!f2fs_sb_has_flexible_inline_xattr(F2FS_I_SB(inode)->sb))
-		return DEFAULT_INLINE_XATTR_ADDRS;
+
 	return F2FS_I(inode)->i_inline_xattr_size;
 }
 
diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index bb876737e653..7f31b22c9efa 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -232,10 +232,19 @@ static int do_read_inode(struct inode *inode)
 	fi->i_extra_isize = f2fs_has_extra_attr(inode) ?
 					le16_to_cpu(ri->i_extra_isize) : 0;
 
-	if (!f2fs_has_inline_xattr(inode))
-		fi->i_inline_xattr_size = 0;
-	else if (f2fs_sb_has_flexible_inline_xattr(sbi->sb))
+	/*
+	 * Previously, we will always reserve DEFAULT_INLINE_XATTR_ADDRS size
+	 * space for inline xattr datas, if inline xattr is not enabled, we
+	 * can expect all zero in reserved area, so for regular or symlink,
+	 * it will be safe to reuse reserved area, but for directory, we
+	 * should keep the reservation for stablizing directory structure.
+	 */
+	if (f2fs_has_extra_attr(inode) &&
+		f2fs_sb_has_flexible_inline_xattr(sbi->sb))
 		fi->i_inline_xattr_size = le16_to_cpu(ri->i_inline_xattr_size);
+	else if (!f2fs_has_inline_xattr(inode) &&
+		(S_ISREG(inode->i_mode) || S_ISLNK(inode->i_mode)))
+		fi->i_inline_xattr_size = 0;
 	else
 		fi->i_inline_xattr_size = DEFAULT_INLINE_XATTR_ADDRS;
 
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index e6f86d5d97b9..a1c56a14c191 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -91,6 +91,8 @@ static struct inode *f2fs_new_inode(struct inode *dir, umode_t mode)
 		f2fs_sb_has_flexible_inline_xattr(sbi->sb) &&
 		f2fs_has_inline_xattr(inode))
 		F2FS_I(inode)->i_inline_xattr_size = sbi->inline_xattr_size;
+	else
+		F2FS_I(inode)->i_inline_xattr_size = 0;
 
 	if (test_opt(sbi, INLINE_DATA) && f2fs_may_inline_data(inode))
 		set_inode_flag(inode, FI_INLINE_DATA);
-- 
2.13.1.388.g69e6b9b4f4a9