INFINIDAT: fixing extend mechanism

There was bug (Bug #1772421) that using extend didn't extend the volume
and only added to its size.
The fix was to calculate size delta inside extend_volume and pass the
calculated delta to the API resize method.

Change-Id: I73035be776a7291ca1578f21cab41c59abc0a534
Closes-Bug: #1772421

cinder/tests/unit/volume/drivers/test_infinidat.py

@@ -103,6 +103,7 @@ class InfiniboxDriverTestCaseBase(test.TestCase):
     def _infinibox_mock(self):
         result = mock.Mock()
         self._mock_volume = mock.Mock()
+        self._mock_volume.get_size.return_value = 1 * units.Gi
         self._mock_volume.has_children.return_value = False
         self._mock_volume.get_logical_units.return_value = []
         self._mock_volume.create_child.return_value = self._mock_volume
@@ -299,6 +300,7 @@ class InfiniboxDriverTestCase(InfiniboxDriverTestCaseBase):
 
     def test_extend_volume(self):
         self.driver.extend_volume(test_volume, 2)
+        self._mock_volume.resize.assert_called_with(1 * units.Gi)
 
     def test_extend_volume_api_fail(self):
         self._mock_volume.resize.side_effect = self._raise_infinisdk

cinder/volume/drivers/infinidat.py

@@ -536,8 +536,9 @@ class InfiniboxVolumeDriver(san.SanISCSIDriver):
     @infinisdk_to_cinder_exceptions
     def extend_volume(self, volume, new_size):
         """Extend the size of a volume."""
-        volume = self._get_infinidat_volume(volume)
-        volume.resize(new_size * capacity.GiB)
+        infinidat_volume = self._get_infinidat_volume(volume)
+        size_delta = new_size * capacity.GiB - infinidat_volume.get_size()
+        infinidat_volume.resize(size_delta)
 
     @infinisdk_to_cinder_exceptions
     def create_snapshot(self, snapshot):

releasenotes/notes/fix-extend-volume-939e30f2e9e516bc.yaml

@@ -0,0 +1,7 @@
+---
+fixes:
+  - |
+    [`bug 1772421 <https://bugs.launchpad.net/keystone/+bug/1772421>`_]
+    INFINIDAT fixed a bug in volume extension feature where volumes
+    were not extended to target size but added the given target size.
+