From f2c77973507fd116c3657df1dc048864a2b16a1c Mon Sep 17 00:00:00 2001
From: Zhang Yi <yi.zhang@huawei.com>
Date: Fri, 10 Sep 2021 16:03:16 +0800
Subject: [PATCH] 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 <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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 9df1ab070fa54..b7c561ad38dd8 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
--
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