diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
index b57a15a..151000f 100644
--- a/fs/btrfs/scrub.c
+++ b/fs/btrfs/scrub.c
@@ -3458,7 +3458,7 @@
 		return ret;
 	}
 
-	map = (struct map_lookup *)em->bdev;
+	map = em->map_lookup;
 	if (em->start != chunk_offset)
 		goto out;