dm thin: fix dangling bio in process_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_bios list before all the remaining @bios.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
Cc: stable@vger.kernel.org

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index be70d38745f7..60cc50685c14 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -1392,9 +1392,9 @@ static void process_deferred_bios(struct pool *pool)
                  */
                 if (ensure_next_mapping(pool)) {
                         spin_lock_irqsave(&pool->lock, flags);
+                        bio_list_add(&pool->deferred_bios, bio);
                         bio_list_merge(&pool->deferred_bios, &bios);
                         spin_unlock_irqrestore(&pool->lock, flags);
-
                         break;
                 }