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exfat: short-circuit zero-byte writes in exfat_file_write_iter

Message ID 7d880675-4aba-4081-84af-1cbacaef17ab@sandeen.net (mailing list archive)
State New
Headers show
Series exfat: short-circuit zero-byte writes in exfat_file_write_iter | expand

Commit Message

Eric Sandeen Feb. 11, 2025, 8:14 p.m. UTC 
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.

Reported-by: Noah <kernel-org-10@maxgrass.eu>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
---

Comments

Yuezhang.Mo@sony.com Feb. 12, 2025, 6:37 a.m. UTC | #1 
Please add the "Fixes" tag.

Fixes: 11a347fb6cef ("exfat: change to get file size from DataLength")
Namjae Jeon Feb. 12, 2025, 2:11 p.m. UTC | #2 
On Wed, Feb 12, 2025 at 3:37 PM Yuezhang.Mo@sony.com
<Yuezhang.Mo@sony.com> wrote:
>
> Please add the "Fixes" tag.
>
> Fixes: 11a347fb6cef ("exfat: change to get file size from DataLength")
I have directly added and applied it to #dev.
Thanks!
diff mbox series

Patch

diff --git a/fs/exfat/file.c b/fs/exfat/file.c
index 05b51e721783..807349d8ea05 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) {