diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 5485377..a6ab989 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -1899,8 +1899,14 @@
 				    iterate_devices_callout_fn fn, void *data)
 {
 	struct dm_snapshot *snap = ti->private;
+	int r;
 
-	return fn(ti, snap->origin, 0, ti->len, data);
+	r = fn(ti, snap->origin, 0, ti->len, data);
+
+	if (!r)
+		r = fn(ti, snap->cow, 0, get_dev_size(snap->cow->bdev), data);
+
+	return r;
 }