From f2c77973507fd116c3657df1dc048864a2b16a1c Mon Sep 17 00:00:00 2001 From: Zhang Yi Date: Fri, 10 Sep 2021 16:03:16 +0800 Subject: ext4: recheck buffer uptodate bit under buffer lock Commit 8e33fadf945a ("ext4: remove an unnecessary if statement in __ext4_get_inode_loc()") forget to recheck buffer's uptodate bit again under buffer lock, which may overwrite the buffer if someone else have already brought it uptodate and changed it. Fixes: 8e33fadf945a ("ext4: remove an unnecessary if statement in __ext4_get_inode_loc()") Cc: stable@kernel.org Signed-off-by: Zhang Yi Reviewed-by: Jan Kara Signed-off-by: Theodore Ts'o Link: https://lore.kernel.org/r/20210910080316.70421-1-yi.zhang@huawei.com --- fs/ext4/inode.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 9df1ab070fa5..b7c561ad38dd 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -4277,6 +4277,12 @@ static int __ext4_get_inode_loc(struct super_block *sb, unsigned long ino, goto has_buffer; lock_buffer(bh); + if (ext4_buffer_uptodate(bh)) { + /* Someone brought it uptodate while we waited */ + unlock_buffer(bh); + goto has_buffer; + } + /* * If we have all information of the inode in memory and this * is the only valid inode in the block, we need not read the -- cgit v1.2.3