Add provider_location to cloned volume

Forced backup was failing when the driver returned a 'provider_location'
for a cloned volume, because the return value for create_cloned_volume()
was ignored in _create_temp_cloned_volume().

Change-Id: I709996316e4c212243629e461d36da4152e995e4
Closes-Bug: 1573126

cinder/tests/unit/test_volume.py

@@ -6369,6 +6369,26 @@ class GenericVolumeDriverTestCase(DriverTestCase):
 
         mock_volume_get.assert_called_with(self.context, vol['id'])
 
+    def test_create_temp_cloned_volume(self):
+        with mock.patch.object(
+                self.volume.driver,
+                'create_cloned_volume') as mock_create_cloned_volume:
+            model_update = {'provider_location': 'dummy'}
+            mock_create_cloned_volume.return_value = model_update
+            vol = tests_utils.create_volume(self.context,
+                                            status='backing-up')
+            cloned_vol = self.volume.driver._create_temp_cloned_volume(
+                self.context, vol)
+            self.assertEqual('dummy', cloned_vol['provider_location'])
+            self.assertEqual('available', cloned_vol['status'])
+
+            mock_create_cloned_volume.return_value = None
+            vol = tests_utils.create_volume(self.context,
+                                            status='backing-up')
+            cloned_vol = self.volume.driver._create_temp_cloned_volume(
+                self.context, vol)
+            self.assertEqual('available', cloned_vol['status'])
+
     @mock.patch.object(utils, 'temporary_chown')
     @mock.patch('six.moves.builtins.open')
     @mock.patch.object(os_brick.initiator.connector,

cinder/volume/driver.py

@@ -1351,15 +1351,19 @@ class BaseVD(object):
         }
         temp_vol_ref = self.db.volume_create(context, temp_volume)
         try:
-            self.create_cloned_volume(temp_vol_ref, volume)
+            # Some drivers return None, because they do not need to update the
+            # model for the volume. For those cases we set the model_update to
+            # an empty dictionary.
+            model_update = self.create_cloned_volume(temp_vol_ref,
+                                                     volume) or {}
         except Exception:
             with excutils.save_and_reraise_exception():
                 self.db.volume_destroy(context.elevated(),
                                        temp_vol_ref['id'])
 
-        self.db.volume_update(context, temp_vol_ref['id'],
+        model_update['status'] = 'available'
-                              {'status': 'available'})
+        self.db.volume_update(context, temp_vol_ref['id'], model_update)
-        return temp_vol_ref
+        return self.db.volume_get(context, temp_vol_ref['id'])
 
     def _create_temp_volume_from_snapshot(self, context, volume, snapshot):
         temp_volume = {