Sync network_info if instance not found before _build_resources yield

If instance is deleted before _build_resources yield, there won't
waiting for network_info sync finish.

So there is race case, when the exception catching for
'InstanceNotFound' in do_build_and_run_instance invoke
'_cleanup_allocated_networks', the '_allocate_network_async' didn't
create port yet. After '_cleanup_allocated_networks' finished,
'_allocate_network_async' create new port for the instance, but there
isn't any cleanup for the new port anymore.

Change-Id: I5027a1aaeb9a2106f7982fd0422f88c4caa20ffb
Related-Bug: #1357055

nova/compute/manager.py

@@ -2172,7 +2172,7 @@ class ComputeManager(manager.Manager):
     def _build_resources(self, context, instance, requested_networks,
             security_groups, image, block_device_mapping):
         resources = {}
-
+        network_info = None
         try:
             network_info = self._build_networks_for_instance(context, instance,
                     requested_networks, security_groups)
@@ -2207,13 +2207,22 @@ class ComputeManager(manager.Manager):
             resources['block_device_info'] = block_device_info
         except (exception.InstanceNotFound,
                 exception.UnexpectedDeletingTaskStateError):
-            raise
+            with excutils.save_and_reraise_exception() as ctxt:
+                # Make sure the async call finishes
+                if network_info is not None:
+                    network_info.wait(do_raise=False)
         except exception.UnexpectedTaskStateError as e:
+            # Make sure the async call finishes
+            if network_info is not None:
+                network_info.wait(do_raise=False)
             raise exception.BuildAbortException(instance_uuid=instance.uuid,
                     reason=e.format_message())
         except Exception:
             LOG.exception(_LE('Failure prepping block device'),
                     instance=instance)
+            # Make sure the async call finishes
+            if network_info is not None:
+                network_info.wait(do_raise=False)
             msg = _('Failure prepping block device.')
             raise exception.BuildAbortException(instance_uuid=instance.uuid,
                     reason=msg)

nova/tests/compute/test_compute_mgr.py

@@ -2667,6 +2667,66 @@ class ComputeManagerBuildInstanceTestCase(test.NoDBTestCase):
         except Exception as e:
             self.assertEqual(test_exception, e)
 
+    @mock.patch('nova.network.model.NetworkInfoAsyncWrapper.wait')
+    @mock.patch(
+        'nova.compute.manager.ComputeManager._build_networks_for_instance')
+    @mock.patch('nova.objects.Instance.save')
+    def test_build_resources_instance_not_found_before_yield(
+            self, mock_save, mock_build_network, mock_info_wait):
+        mock_build_network.return_value = self.network_info
+        expected_exc = exception.InstanceNotFound(
+            instance_id=self.instance.uuid)
+        mock_save.side_effect = expected_exc
+        try:
+            with self.compute._build_resources(self.context, self.instance,
+                    self.requested_networks, self.security_groups,
+                    self.image, self.block_device_mapping):
+                raise
+        except Exception as e:
+            self.assertEqual(expected_exc, e)
+        mock_build_network.assert_called_once_with(self.context, self.instance,
+                self.requested_networks, self.security_groups)
+        mock_info_wait.assert_called_once_with(do_raise=False)
+
+    @mock.patch('nova.network.model.NetworkInfoAsyncWrapper.wait')
+    @mock.patch(
+        'nova.compute.manager.ComputeManager._build_networks_for_instance')
+    @mock.patch('nova.objects.Instance.save')
+    def test_build_resources_unexpected_task_error_before_yield(
+            self, mock_save, mock_build_network, mock_info_wait):
+        mock_build_network.return_value = self.network_info
+        mock_save.side_effect = exception.UnexpectedTaskStateError(
+            expected='', actual='')
+        try:
+            with self.compute._build_resources(self.context, self.instance,
+                    self.requested_networks, self.security_groups,
+                    self.image, self.block_device_mapping):
+                raise
+        except exception.BuildAbortException:
+            pass
+        mock_build_network.assert_called_once_with(self.context, self.instance,
+                self.requested_networks, self.security_groups)
+        mock_info_wait.assert_called_once_with(do_raise=False)
+
+    @mock.patch('nova.network.model.NetworkInfoAsyncWrapper.wait')
+    @mock.patch(
+        'nova.compute.manager.ComputeManager._build_networks_for_instance')
+    @mock.patch('nova.objects.Instance.save')
+    def test_build_resources_exception_before_yield(
+            self, mock_save, mock_build_network, mock_info_wait):
+        mock_build_network.return_value = self.network_info
+        mock_save.side_effect = Exception()
+        try:
+            with self.compute._build_resources(self.context, self.instance,
+                    self.requested_networks, self.security_groups,
+                    self.image, self.block_device_mapping):
+                raise
+        except exception.BuildAbortException:
+            pass
+        mock_build_network.assert_called_once_with(self.context, self.instance,
+                self.requested_networks, self.security_groups)
+        mock_info_wait.assert_called_once_with(do_raise=False)
+
     def test_build_resources_aborts_on_cleanup_failure(self):
         self.mox.StubOutWithMock(self.compute, '_build_networks_for_instance')
         self.mox.StubOutWithMock(self.compute, '_shutdown_instance')