ntfs: flush the block device when syncing a directory

ntfs_dir_fsync() writes directory metadata and calls sync_blockdev(),
but does not flush the block device write cache. A successful fsync()
can therefore leave the directory's metadata in a volatile device cache.

Issue a cache flush after successful writeback and return any flush error.
This matches the regular-file fsync and syncfs paths.

With QEMU blkdebug injecting -EIO for flush_to_disk, fsync() on an NTFS
directory returned 0 before this change while syncfs() returned -EIO.
After this change, both return -EIO. A kretprobe confirmed the flush
error in the directory fsync path.

Fixes: 1e9ea7e04472 ("Revert "fs: Remove NTFS classic"")
Cc: stable@vger.kernel.org
Signed-off-by: DaeMyung Kang <charsyam@gmail.com>
Reviewed-by: Baolin Liu <liubaolin@kylinos.cn>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>

0 files changed, 0 insertions, 0 deletions