diff --git a/blockdev.c b/blockdev.c
index 5d6a13dea9..4d141e9a1f 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1774,7 +1774,7 @@ static void drive_backup_prepare(BlkActionState *common, Error **errp)
     assert(common->action->type == TRANSACTION_ACTION_KIND_DRIVE_BACKUP);
     backup = common->action->u.drive_backup.data;
 
-    bs = qmp_get_root_bs(backup->device, errp);
+    bs = bdrv_lookup_bs(backup->device, backup->device, errp);
     if (!bs) {
         return;
     }