[Devel] [PATCH VZ9] dm-qcow2 check if files are opened with O_DIRECT

[Alexander Atanasov]

Check that passed file descriptors are using O_DIRECT.
Required to avoid data integrity problems caused by
the page cache.

https://jira.sw.ru/browse/PSBM-142050
Signed-off-by: Alexander Atanasov <alexander.atanasov at virtuozzo.com>
---
 drivers/md/dm-qcow2-target.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/md/dm-qcow2-target.c b/drivers/md/dm-qcow2-target.c
index 9a6f970343ec..995679b3cd98 100644
--- a/drivers/md/dm-qcow2-target.c
+++ b/drivers/md/dm-qcow2-target.c
@@ -678,6 +678,9 @@ static int qcow2_attach_file(struct dm_target *ti, struct qcow2_target *tgt,
 	if (!S_ISREG(file_inode(file)->i_mode))
 		return -EINVAL;
 
+	if (!(file->f_flags & O_DIRECT))
+		return -EINVAL;
+
 	mode = tgt->top != qcow2 ? FMODE_READ : dm_table_get_mode(ti->table);
 	mode &= (FMODE_READ|FMODE_WRITE);
 	if (mode & ~(file->f_mode & (FMODE_READ|FMODE_WRITE)))
-- 
2.31.1