dm thin: fix dangling bio in process_thin_deferred_bios() error path

If unable to ensure_next_mapping() we must add the current bio, which
was removed from the @bios list via bio_list_pop, back to the
deferred_list before all the remaining @bios.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>

diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 002b15600fea13aee9ecf86468c282aefa418dca..05ab9bf6b4fe8b9746a91cbc49652c140e469b21 100644 (file)
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -1685,6 +1685,7 @@ static void process_thin_deferred_bios(struct thin_c *tc)
                 */
                if (ensure_next_mapping(pool)) {
                        spin_lock_irqsave(&tc->lock, flags);
+                       bio_list_add(&tc->deferred_bio_list, bio);
                        bio_list_merge(&tc->deferred_bio_list, &bios);
                        spin_unlock_irqrestore(&tc->lock, flags);
                        break;