This is a note to let you know that I've just added the patch titled
f2fs: fix to force keeping write barrier for strict fsync mode
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
f2fs-fix-to-force-keeping-write-barrier-for-strict-f.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 17b19b515470838e347eaec1c9e74a091c46af1c
Author: Chao Yu <chao@xxxxxxxxxx>
Date: Tue Jul 20 09:03:29 2021 +0800
f2fs: fix to force keeping write barrier for strict fsync mode
[ Upstream commit 2787991516468bfafafb9bf2b45a848e6b202e7c ]
[1] https://www.mail-archive.com/linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx/msg15126.html
As [1] reported, if lower device doesn't support write barrier, in below
case:
- write page #0; persist
- overwrite page #0
- fsync
- write data page #0 OPU into device's cache
- write inode page into device's cache
- issue flush
If SPO is triggered during flush command, inode page can be persisted
before data page #0, so that after recovery, inode page can be recovered
with new physical block address of data page #0, however there may
contains dummy data in new physical block address.
Then what user will see is: after overwrite & fsync + SPO, old data in
file was corrupted, if any user do care about such case, we can suggest
user to use STRICT fsync mode, in this mode, we will force to use atomic
write sematics to keep write order in between data/node and last node,
so that it avoids potential data corruption during fsync().
Signed-off-by: Chao Yu <chao@xxxxxxxxxx>
Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
Stable-dep-of: 278a6253a673 ("f2fs: fix to relocate check condition in f2fs_fallocate()")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 9023083a98a64..02971d6b347e0 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -297,6 +297,18 @@ static int f2fs_do_sync_file(struct file *file, loff_t start, loff_t end,
f2fs_exist_written_data(sbi, ino, UPDATE_INO))
goto flush_out;
goto out;
+ } else {
+ /*
+ * for OPU case, during fsync(), node can be persisted before
+ * data when lower device doesn't support write barrier, result
+ * in data corruption after SPO.
+ * So for strict fsync mode, force to use atomic write sematics
+ * to keep write order in between data/node and last node to
+ * avoid potential data corruption.
+ */
+ if (F2FS_OPTION(sbi).fsync_mode ==
+ FSYNC_MODE_STRICT && !atomic)
+ atomic = true;
}
go_write:
/*
