This is a note to let you know that I've just added the patch titled
exfat: short-circuit zero-byte writes in exfat_file_write_iter
to the 6.12-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:
exfat-short-circuit-zero-byte-writes-in-exfat_file_w.patch
and it can be found in the queue-6.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 9c9fab59b353d3e6da6c31c029aaa282137626e9
Author: Eric Sandeen <sandeen@xxxxxxxxxx>
Date: Tue Feb 11 14:14:21 2025 -0600
exfat: short-circuit zero-byte writes in exfat_file_write_iter
[ Upstream commit fda94a9919fd632033979ad7765a99ae3cab9289 ]
When generic_write_checks() returns zero, it means that
iov_iter_count() is zero, and there is no work to do.
Simply return success like all other filesystems do, rather than
proceeding down the write path, which today yields an -EFAULT in
generic_perform_write() via the
(fault_in_iov_iter_readable(i, bytes) == bytes) check when bytes
== 0.
Fixes: 11a347fb6cef ("exfat: change to get file size from DataLength")
Reported-by: Noah <kernel-org-10@xxxxxxxxxxx>
Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
Reviewed-by: Yuezhang Mo <Yuezhang.Mo@xxxxxxxx>
Signed-off-by: Namjae Jeon <linkinjeon@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/exfat/file.c b/fs/exfat/file.c
index 05b51e7217838..807349d8ea050 100644
--- a/fs/exfat/file.c
+++ b/fs/exfat/file.c
@@ -587,7 +587,7 @@ static ssize_t exfat_file_write_iter(struct kiocb *iocb, struct iov_iter *iter)
valid_size = ei->valid_size;
ret = generic_write_checks(iocb, iter);
- if (ret < 0)
+ if (ret <= 0)
goto unlock;
if (iocb->ki_flags & IOCB_DIRECT) {
