VNX: delete the LUN from VNX backend

Async migration is used in the process of creating a volume from a
snapshot and an internal temp snapshot is created.

Because the temp snapshot isn't deleted, the LUN hosting the temp
snapshot cannot be deleted from the VNX storage.

For example, a new volume, V2, is created from snapshot S1 of volume V1.
An internal temp snapshot S2 is created from copying S1. V1 now has two
snapshots, S1 and S2. Although we delete V1, V2 and S1 from Cinder,
S2 which is Cinder user-invisible isn't deleted and which causes V1 left
on VNX too.

The fix makes sure the snapshot S2 is deleted. Then the delay deletion
on V1 can be executed successfully.

Change-Id: Ib86729488ebfb0aea5d5d4f815a64e00258040e7
Closes-bug: #1794646

cinder/tests/unit/volume/drivers/dell_emc/vnx/mocked_cinder.yaml

@@ -127,6 +127,12 @@ test_delete_async_volume:
 test_delete_async_volume_migrating:
   volume: *volume_base
 
+test_delete_async_volume_not_from_snapshot:
+  volume: *volume_base
+
+test_delete_async_volume_from_snapshot:
+  volume: *volume_base
+
 test_retype_need_migration_when_host_changed:
   volume: *volume_base
   host:

cinder/tests/unit/volume/drivers/dell_emc/vnx/mocked_vnx.yaml

@@ -1480,6 +1480,20 @@ test_delete_async_volume_migrating:
       get_lun: *lun_used_by_feature
       get_snap: *snap_test_delete_async_volume
 
+test_delete_async_volume_not_from_snapshot:
+  vnx:
+    _methods:
+      get_lun: *lun_test_delete_lun
+
+test_delete_async_volume_from_snapshot:
+  snap: &snap_test_delete_async_volume_from_snapshot
+    _methods:
+      delete:
+  vnx:
+    _methods:
+      get_lun: *lun_test_delete_lun
+      get_snap: *snap_test_delete_async_volume_from_snapshot
+
 test_enable_compression:
   lun:
     _properties:

cinder/tests/unit/volume/drivers/dell_emc/vnx/test_adapter.py

@@ -443,6 +443,31 @@ class TestCommonAdapter(test_base.TestCase):
         lun = vnx_common.client.vnx.get_lun()
         lun.delete.assert_called_with(force_detach=True, detach_from_sg=True)
 
+    @res_mock.mock_driver_input
+    @res_mock.patch_common_adapter
+    def test_delete_async_volume_not_from_snapshot(self, vnx_common, mocked,
+                                                   mocked_input):
+        volume = mocked_input['volume']
+        volume.metadata = {'async_migrate': 'True'}
+        vnx_common.force_delete_lun_in_sg = True
+        vnx_common.delete_volume(volume)
+        lun = vnx_common.client.vnx.get_lun()
+        lun.delete.assert_called_with(force_detach=True, detach_from_sg=True)
+
+    @res_mock.mock_driver_input
+    @res_mock.patch_common_adapter
+    def test_delete_async_volume_from_snapshot(self, vnx_common, mocked,
+                                               mocked_input):
+        volume = mocked_input['volume']
+        volume.metadata = {'async_migrate': 'True'}
+        volume.snapshot_id = 'snap'
+        vnx_common.force_delete_lun_in_sg = True
+        vnx_common.delete_volume(volume)
+        lun = vnx_common.client.vnx.get_lun()
+        lun.delete.assert_called_with(force_detach=True, detach_from_sg=True)
+        snap = vnx_common.client.vnx.get_snap()
+        snap.delete.assert_called_with()
+
     @utils.patch_extra_specs_validate(side_effect=exception.InvalidVolumeType(
         reason='fake_reason'))
     @res_mock.patch_common_adapter

cinder/volume/drivers/dell_emc/vnx/adapter.py

@@ -801,8 +801,8 @@ class CommonAdapter(replication.ReplicationAdapter):
             # for later deletion
             self.client.delay_delete_lun(volume.name)
         # Case 2. Migration already finished, try to delete the temp snap
-        # only when it's a cloned volume.
-        if async_migrate and volume.source_volid:
+        # when it's a cloned volume or created from snapshot.
+        if async_migrate and (volume.source_volid or volume.snapshot_id):
             self.client.delete_snapshot(utils.construct_snap_name(volume))
 
     def extend_volume(self, volume, new_size):

cinder/volume/drivers/dell_emc/vnx/driver.py

@@ -84,9 +84,11 @@ class VNXDriver(driver.ManageableVD,
           13.0.0 - Fix bug https://bugs.launchpad.net/cinder/+bug/1817385 to
                    make sure sg can be created again after it was destroyed
                    under `destroy_empty_stroage_group` setting to `True`
+          14.0.0 - Fix bug 1794646: failed to delete LUNs from backend due to
+                   the temporary snapshots on them wasn't deleted.
     """
 
-    VERSION = '13.00.00'
+    VERSION = '14.00.00'
     VENDOR = 'Dell EMC'
     # ThirdPartySystems wiki page
     CI_WIKI_NAME = "EMC_VNX_CI"

releasenotes/notes/vnx-fail-delete-lun-due-to-tmp-snapshot-edd3cdd85e28be60.yaml

@@ -0,0 +1,9 @@
+---
+fixes:
+  - |
+    Dell EMC VNX Cinder Driver: Fixes `bug 1794646
+    <https://bugs.launchpad.net/cinder/+bug/1794646>`__ to delete the LUN from
+    the VNX storage. Because a temporary snapshot is created from the LUN
+    during creating a volume from a snapshot and isn't deleted, the LUN cannot
+    be deleted before its snapshot is deleted. The fix makes sure the temp
+    snapshot is deleted.