Commit fda94a99 authored by Eric Sandeen's avatar Eric Sandeen Committed by Namjae Jeon
Browse files

exfat: short-circuit zero-byte writes in exfat_file_write_iter 



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: 11a347fb ("exfat: change to get file size from DataLength")
Reported-by: default avatarNoah <kernel-org-10@maxgrass.eu>
Signed-off-by: default avatarEric Sandeen <sandeen@redhat.com>
Reviewed-by: default avatarYuezhang Mo <Yuezhang.Mo@sony.com>
Signed-off-by: default avatarNamjae Jeon <linkinjeon@kernel.org>
parent 9da33619

fs/exfat/file.c

+1 −1
Original line number Diff line number Diff line
@@ -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) {