Avoid leaking BDMs for deleted instances.

Fixes bug 1069099

Previously when an instance was deleted, the corresponding entries
in the block device mappings table were not also marked as deleted.

Change-Id: I0184eb2f02a9ed363019c585efffdfdb95f0bb43

nova/compute/manager.py

@@ -912,6 +912,11 @@ def _delete_instance(self, context, instance):
         self.db.instance_destroy(context, instance_uuid)
         system_meta = self.db.instance_system_metadata_get(context,
             instance_uuid)
+
+        # ensure block device mappings are not leaked
+        for bdm in self._get_instance_volume_bdms(context, instance_uuid):
+            self.db.block_device_mapping_destroy(context, bdm['id'])
+
         self._notify_about_instance_usage(context, instance, "delete.end",
                 system_metadata=system_meta)
 

nova/tests/compute/test_compute.py

@@ -617,6 +617,9 @@ def fake_volume_get(self, context, volume_id):
         instances = db.instance_get_all(context.get_admin_context())
         LOG.info(_("After terminating instances: %s"), instances)
         self.assertEqual(len(instances), 0)
+        bdms = db.block_device_mapping_get_all_by_instance(self.context,
+                                                           instance['uuid'])
+        self.assertEqual(len(bdms), 0)
 
     def test_terminate_no_network(self):
         # This is as reported in LP bug 1008875