Make sure instance data is always refreshed

Fixes bug 1078793

When updating an instance's instance_type_id, the 'instance_type' joined
to the instance is not updated.  This updates that.  A DB API test is added
that failed before and passes now.

Also: Some cases of passing stale instance data within resize_instance()
and finish_resize() were found and addressed.

Change-Id: If335cc286a71597d3100425080e51c75aeec7a50

3 files changed, 36 insertions, 9 deletions

diff --git a/nova/compute/manager.py b/nova/compute/manager.py
index be20c7a40..a5084d6fe 100644
--- a/nova/compute/manager.py
+++ b/nova/compute/manager.py
@@ -1837,9 +1837,9 @@ class ComputeManager(manager.SchedulerDependentManager):
                                      migration['id'],
                                      {'status': 'migrating'})
 
-            self._instance_update(context, instance['uuid'],
-                                  task_state=task_states.RESIZE_MIGRATING,
-                                  expected_task_state=task_states.RESIZE_PREP)
+            instance = self._instance_update(context, instance['uuid'],
+                    task_state=task_states.RESIZE_MIGRATING,
+                    expected_task_state=task_states.RESIZE_PREP)
 
             self._notify_about_instance_usage(
                 context, instance, "resize.start", network_info=network_info)
@@ -1861,11 +1861,11 @@ class ComputeManager(manager.SchedulerDependentManager):
                                                  migration['id'],
                                                  {'status': 'post-migrating'})
 
-            self._instance_update(context, instance['uuid'],
-                                  host=migration['dest_compute'],
-                                  task_state=task_states.RESIZE_MIGRATED,
-                                  expected_task_state=task_states.
-                                      RESIZE_MIGRATING)
+            instance = self._instance_update(context, instance['uuid'],
+                    host=migration['dest_compute'],
+                    task_state=task_states.RESIZE_MIGRATED,
+                    expected_task_state=task_states.
+                    RESIZE_MIGRATING)
 
             self.compute_rpcapi.finish_resize(context, instance,
                     migration, image, disk_info,
@@ -1910,7 +1910,7 @@ class ComputeManager(manager.SchedulerDependentManager):
 
         network_info = self._get_instance_nw_info(context, instance)
 
-        self._instance_update(context, instance['uuid'],
+        instance = self._instance_update(context, instance['uuid'],
                               task_state=task_states.RESIZE_FINISH,
                               expected_task_state=task_states.RESIZE_MIGRATED)
 
diff --git a/nova/db/sqlalchemy/api.py b/nova/db/sqlalchemy/api.py
index 007e83cbe..3cba27c1e 100644
--- a/nova/db/sqlalchemy/api.py
+++ b/nova/db/sqlalchemy/api.py
@@ -1813,6 +1813,13 @@ def _instance_update(context, instance_uuid, values, copy_old_instance=False):
 
         instance_ref.update(values)
         instance_ref.save(session=session)
+        if 'instance_type_id' in values:
+            # NOTE(comstud): It appears that sqlalchemy doesn't refresh
+            # the instance_type model after you update the ID.  You end
+            # up with an instance_type model that only has 'id' updated,
+            # but the rest of the model has the data from the old
+            # instance_type.
+            session.refresh(instance_ref['instance_type'])
 
     return (old_instance_ref, instance_ref)
 
diff --git a/nova/tests/test_db_api.py b/nova/tests/test_db_api.py
index 39d3e1b1f..31d1b01b2 100644
--- a/nova/tests/test_db_api.py
+++ b/nova/tests/test_db_api.py
@@ -272,6 +272,26 @@ class DbApiTestCase(test.TestCase):
         system_meta = db.instance_system_metadata_get(ctxt, instance.uuid)
         self.assertEqual('baz', system_meta['original_image_ref'])
 
+    def test_instance_update_of_instance_type_id(self):
+        ctxt = context.get_admin_context()
+
+        inst_type1 = db.instance_type_get_by_name(ctxt, 'm1.tiny')
+        inst_type2 = db.instance_type_get_by_name(ctxt, 'm1.small')
+
+        values = {'instance_type_id': inst_type1['id']}
+        instance = db.instance_create(ctxt, values)
+
+        self.assertEqual(instance['instance_type']['id'], inst_type1['id'])
+        self.assertEqual(instance['instance_type']['name'],
+                inst_type1['name'])
+
+        values = {'instance_type_id': inst_type2['id']}
+        instance = db.instance_update(ctxt, instance['uuid'], values)
+
+        self.assertEqual(instance['instance_type']['id'], inst_type2['id'])
+        self.assertEqual(instance['instance_type']['name'],
+                inst_type2['name'])
+
     def test_instance_update_with_and_get_original(self):
         ctxt = context.get_admin_context()