dm thin: fix dangling bio in process_deferred_bios error path

commit fe76cd88e654124d1431bb662a0fc6e99ca811a5 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index be70d38745f7a7f5da51bd4ba83a29afe851b238..60cc50685c14afae7c7f734971ca4453ec33bae8 100644 (file)
--- 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;
                }