NEC driver: fix a non-disruptive backup error

When attaching a snapshot to a node,
NEC driver automatically creates and attaches LUN-0
if the node does not have it yet.
The LUN-0 is reserved for storage functions control.

Currently, the driver does not update a LUN list after creating LUN-0
and selects the already used LUN to attach the snapshot.
That causes a non-disruptive backup error.

This patch adds the LUN list update.
The list is stored in `ldset' variable.

Change-Id: I6d5d34ac802ecf6239f2d7e1a2a13c58ce5db263
Closes-Bug: #1852201
(cherry picked from commit 04f8e46659)

cinder/tests/unit/volume/drivers/nec/test_volume.py

@@ -1211,6 +1211,28 @@ class NonDisruptiveBackup_test(volume_helper.MStorageDSVDriver,
         self.assertIsNotNone(ret)
         self.assertEqual('fibre_channel', ret['driver_volume_type'])
 
+        ldset_lds0 = {'ldsetname': 'LX:OpenStack1', 'lds': {},
+                      'protocol': 'FC',
+                      'wwpn': ['1000-0090-FAA0-786A', '1000-0090-FAA0-786B'],
+                      'port': []}
+        ldset_lds1 = {'ldsetname': 'LX:OpenStack1',
+                      'lds': {16: {'ldn': 16, 'lun': 0}},
+                      'protocol': 'FC',
+                      'wwpn': ['1000-0090-FAA0-786A', '1000-0090-FAA0-786B'],
+                      'port': []}
+        return_ldset = [ldset_lds0, ldset_lds1]
+        self.mock_object(self, '_validate_fcldset_exist',
+                         side_effect=return_ldset)
+        mocker = self.mock_object(self._cli, 'addldsetld',
+                                  mock.Mock(wraps=self._cli.addldsetld))
+        connector = {'wwpns': ["10000090FAA0786A", "10000090FAA0786B"]}
+        ret = self.fc_initialize_connection_snapshot(snap, connector)
+        self.assertIsNotNone(ret)
+        self.assertEqual('fibre_channel', ret['driver_volume_type'])
+        mocker.assert_any_call('LX:OpenStack1', 'LX:__ControlVolume_10h', 0)
+        mocker.assert_any_call('LX:OpenStack1',
+                               'LX:287RbQoP7VdwR1WsPC2fZT_l', 1)
+
     def test_terminate_connection_snapshot(self):
         ctx = context.RequestContext('admin', 'fake', True)
         snap = fake_volume_obj(ctx, id="46045673-41e7-44a7-9333-02f07feab04b")

cinder/volume/drivers/nec/volume_helper.py

@@ -854,6 +854,8 @@ class MStorageDriver(volume_common.MStorageVolumeCommon):
 
         LOG.debug('configure backend.')
         lun0 = [ld for (ldn, ld) in ldset['lds'].items() if ld['lun'] == 0]
+        # NEC Storage cannot create an LV with LUN 0.
+        # Create a CV with LUN 0 to use the other LUN for an LV.
         if not lun0:
             LOG.debug('create and attach control volume.')
             used_ldns.append(lvldn)
@@ -867,6 +869,7 @@ class MStorageDriver(volume_common.MStorageVolumeCommon):
             xml = self._cli.view_all(self._properties['ismview_path'])
             pools, lds, ldsets, used_ldns, hostports, max_ld_count = (
                 self.configs(xml))
+            ldset = validate_ldset_exist(ldsets, connector)
 
         self._cli.lvbind(bvname, lvname[3:], lvldn)
         self._cli.lvlink(svname[3:], lvname[3:])