Attachment lost after migrating in-use volume

Without proper refresh, attachment info are lost after
migrating in-use volumes. This is to fix the problem.

Change-Id: I31012a1871b85e038e6595097ad25224488d72a1
Closes-bug: #1614371

cinder/objects/volume.py

@@ -463,6 +463,7 @@ class Volume(base.CinderPersistentObject, base.CinderObject,
             setattr(self, key, value)
             setattr(dest_volume, key, value_to_dst)
 
+        self.save()
         dest_volume.save()
         return dest_volume
 

cinder/tests/unit/objects/test_volume.py

@@ -380,6 +380,9 @@ class TestVolume(test_objects.BaseObjectsTestCase):
                          updated_dest_volume.display_description)
         self.assertEqual(src_volume.id, updated_dest_volume._name_id)
         self.assertTrue(volume_update.called)
+        volume_update.assert_has_calls([
+            mock.call(self.context, src_volume.id, mock.ANY),
+            mock.call(self.context, dest_volume.id, mock.ANY)])
         ctxt, vol_id, updates = volume_update.call_args[0]
         self.assertNotIn('volume_type', updates)
 

cinder/volume/manager.py

@@ -1793,11 +1793,15 @@ class VolumeManager(manager.SchedulerDependentManager):
         volume.save()
 
         # Detach the source volume (if it fails, don't fail the migration)
+        # As after detach and refresh, volume_attchments will be None.
+        # We keep volume_attachment for later attach.
+        if orig_volume_status == 'in-use':
+            attachments = volume.volume_attachment
+        else:
+            attachments = None
         try:
-            if orig_volume_status == 'in-use':
-                attachments = volume.volume_attachment
-                for attachment in attachments:
-                    self.detach_volume(ctxt, volume.id, attachment['id'])
+            for attachment in attachments:
+                self.detach_volume(ctxt, volume.id, attachment['id'])
         except Exception as ex:
             LOG.error(_LE("Detach migration source volume failed:  %(err)s"),
                       {'err': ex}, resource=volume)
@@ -1819,7 +1823,6 @@ class VolumeManager(manager.SchedulerDependentManager):
                    'migration_status': 'success'}
 
         if orig_volume_status == 'in-use':
-            attachments = volume.volume_attachment
             for attachment in attachments:
                 rpcapi.attach_volume(ctxt, volume,
                                      attachment['instance_uuid'],