This is a note to let you know that I've just added the patch titled
exfat: fix file being changed by unaligned direct write
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-fix-file-being-changed-by-unaligned-direct-wri.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 303c7efb957cdb937fb2ea34fa6351231bdc1cb6
Author: Yuezhang Mo <Yuezhang.Mo@xxxxxxxx>
Date: Thu Oct 17 09:25:06 2024 +0800
exfat: fix file being changed by unaligned direct write
[ Upstream commit 2e94e5bb94a3e641a25716a560bf474225fda83c ]
Unaligned direct writes are invalid and should return an error
without making any changes, rather than extending ->valid_size
and then returning an error. Therefore, alignment checking is
required before extending ->valid_size.
Fixes: 11a347fb6cef ("exfat: change to get file size from DataLength")
Signed-off-by: Yuezhang Mo <Yuezhang.Mo@xxxxxxxx>
Co-developed-by: Namjae Jeon <linkinjeon@xxxxxxxxxx>
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 a25d7eb789f4c..fb38769c3e39d 100644
--- a/fs/exfat/file.c
+++ b/fs/exfat/file.c
@@ -584,6 +584,16 @@ static ssize_t exfat_file_write_iter(struct kiocb *iocb, struct iov_iter *iter)
if (ret < 0)
goto unlock;
+ if (iocb->ki_flags & IOCB_DIRECT) {
+ unsigned long align = pos | iov_iter_alignment(iter);
+
+ if (!IS_ALIGNED(align, i_blocksize(inode)) &&
+ !IS_ALIGNED(align, bdev_logical_block_size(inode->i_sb->s_bdev))) {
+ ret = -EINVAL;
+ goto unlock;
+ }
+ }
+
if (pos > valid_size) {
ret = exfat_extend_valid_size(file, pos);
if (ret < 0 && ret != -ENOSPC) {
