Fix resource tracker updates during instance evacuation

Current _update_usage_from_migrations code takes into account
only REBUILDING task state, while not handling properly rebuilding
spawn and rebuilding volume attachments. This can cause issues with
numa topologies or pci devices if several instances are being
evacuated and some of them begin evacuation prior to
update_available_resource periodic pass and others immediately after,
causing latter ones to claim e.g. already pinned cpus.

Closes-Bug: 1791075
Change-Id: I22aa680b00ae839c4acbc06cbfbc56dd27d5ab73
(cherry picked from commit d8f7638d02)

nova/compute/resource_tracker.py

@@ -64,9 +64,8 @@ def _instance_in_resize_state(instance):
         return True
 
     if (vm in [vm_states.ACTIVE, vm_states.STOPPED]
-            and task in [task_states.RESIZE_PREP,
+            and task in (
-            task_states.RESIZE_MIGRATING, task_states.RESIZE_MIGRATED,
+                task_states.resizing_states + task_states.rebuild_states)):
-            task_states.RESIZE_FINISH, task_states.REBUILDING]):
         return True
 
     return False

nova/compute/task_states.py

@@ -123,3 +123,10 @@ ALLOW_REBOOT = [None, REBOOTING, REBOOT_PENDING, REBOOT_STARTED, RESUMING,
 # These states indicate a reboot
 soft_reboot_states = (REBOOTING, REBOOT_PENDING, REBOOT_STARTED)
 hard_reboot_states = (REBOOTING_HARD, REBOOT_PENDING_HARD, REBOOT_STARTED_HARD)
+
+# These states indicate a resize in progress
+resizing_states = (RESIZE_PREP, RESIZE_MIGRATING, RESIZE_MIGRATED,
+                   RESIZE_FINISH)
+
+# These states indicate a rebuild
+rebuild_states = (REBUILDING, REBUILD_BLOCK_DEVICE_MAPPING, REBUILD_SPAWNING)

nova/tests/unit/compute/test_resource_tracker.py

@@ -2747,6 +2747,27 @@ class TestUpdateUsageFromMigrations(BaseTestCase):
         self.assertFalse(upd_mock.called)
         self.assertEqual(mig1.status, "error")
 
+    @mock.patch('nova.objects.migration.Migration.save')
+    @mock.patch.object(resource_tracker.ResourceTracker,
+                       '_update_usage_from_migration')
+    def test_evacuate_and_resizing_states(self, mock_update_usage, mock_save):
+        self._setup_rt()
+        migration_context = objects.MigrationContext(migration_id=1)
+        instance = objects.Instance(
+            vm_state=vm_states.STOPPED, task_state=None,
+            migration_context=migration_context)
+        migration = objects.Migration(
+            source_compute='other-host', source_node='other-node',
+            dest_compute=_HOSTNAME, dest_node=_NODENAME,
+            instance_uuid=uuids.instance, id=1, instance=instance)
+        for state in task_states.rebuild_states + task_states.resizing_states:
+            instance.task_state = state
+            self.rt._update_usage_from_migrations(
+                mock.sentinel.ctx, [migration], _NODENAME)
+            mock_update_usage.assert_called_once_with(
+                mock.sentinel.ctx, instance, migration, _NODENAME)
+            mock_update_usage.reset_mock()
+
 
 class TestUpdateUsageFromInstance(BaseTestCase):