Remove RetypeVD class, fix NFS driver retype

retype() only exists in the deprecated VolumeDriver() class
and not BaseVD.  This means that drivers inheriting from *VD
hit attribute errors when trying to call driver.retype().

The thinking here is that RetypeVD isn't really necessary,
since all drivers must implement some version of the retype
method (even if it's a no-op with just a standard return code).

Therefore, just rely on this being in the base driver class(es)
rather than making it a separate abc class.

Closes-Bug: #1478987
Related-Bug: #1471807

Change-Id: Ie0c6f23caf68080a05a10cc7ad245878a057fb02

cinder/tests/unit/test_nfs.py

@@ -1308,3 +1308,17 @@ class NfsDriverDoSetupTestCase(test.TestCase):
                           v1,
                           v2,
                           mock.sentinel)
+
+    def test_retype_is_there(self):
+        "Ensure that driver.retype() is there."""
+
+        drv = nfs.NfsDriver(configuration=self.configuration)
+        v1 = DumbVolume()
+
+        ret = drv.retype(self.context,
+                         v1,
+                         mock.sentinel.new_type,
+                         mock.sentinel.diff,
+                         mock.sentinel.host)
+
+        self.assertEqual((False, None), ret)

cinder/volume/driver.py

@@ -922,6 +922,9 @@ class BaseVD(object):
     def validate_connector_has_setting(connector, setting):
         pass
 
+    def retype(self, context, volume, new_type, diff, host):
+        return False, None
+
     # #######  Interface methods for DataPath (Connector) ########
     @abc.abstractmethod
     def ensure_export(self, context, volume):
@@ -1101,42 +1104,6 @@ class ExtendVD(object):
         return
 
 
-@six.add_metaclass(abc.ABCMeta)
-class RetypeVD(object):
-    @abc.abstractmethod
-    def retype(self, context, volume, new_type, diff, host):
-        """Convert the volume to be of the new type.
-
-        Returns either:
-        A boolean indicating whether the retype occurred, or
-        A tuple (retyped, model_update) where retyped is a boolean
-        indicating if the retype occurred, and the model_update includes
-        changes for the volume db.
-        if diff['extra_specs'] includes 'replication' then:
-            if  ('True', _ ) then replication should be disabled:
-                Volume replica should be deleted
-                volume['replication_status'] should be changed to 'disabled'
-                volume['replication_extended_status'] = None
-                volume['replication_driver_data'] = None
-            if  (_, 'True') then replication should be enabled:
-                Volume replica (secondary) should be created, and replication
-                should be setup between the volume and the newly created
-                replica
-                volume['replication_status'] = 'copying'
-                volume['replication_extended_status'] = driver specific value
-                volume['replication_driver_data'] = driver specific value
-
-        :param ctxt: Context
-        :param volume: A dictionary describing the volume to migrate
-        :param new_type: A dictionary describing the volume type to convert to
-        :param diff: A dictionary with the difference between the two types
-        :param host: A dictionary describing the host to migrate to, where
-                     host['host'] is its name, and host['capabilities'] is a
-                     dictionary of its reported capabilities.
-        """
-        return False, None
-
-
 @six.add_metaclass(abc.ABCMeta)
 class TransferVD(object):
     def accept_transfer(self, context, volume, new_user, new_project):
@@ -1297,7 +1264,7 @@ class ReplicaVD(object):
 
 class VolumeDriver(ConsistencyGroupVD, TransferVD, ManageableVD, ExtendVD,
                    CloneableVD, CloneableImageVD, SnapshotVD, ReplicaVD,
-                   RetypeVD, LocalVD, MigrateVD, BaseVD):
+                   LocalVD, MigrateVD, BaseVD):
     """This class will be deprecated soon.
 
     Please use the abstract classes above for new drivers.

cinder/volume/drivers/ibm/gpfs.py

@@ -110,7 +110,7 @@ def _sizestr(size_in_g):
 class GPFSDriver(driver.ConsistencyGroupVD, driver.ExtendVD,
                  driver.LocalVD, driver.TransferVD, driver.CloneableVD,
                  driver.CloneableImageVD, driver.SnapshotVD,
-                 driver.RetypeVD, driver.MigrateVD,
+                 driver.MigrateVD,
                  driver.BaseVD):
     """Implements volume functions using GPFS primitives.
 

cinder/volume/drivers/ibm/storwize_svc/__init__.py

@@ -133,7 +133,6 @@ class StorwizeSVCDriver(san.SanDriver,
                         driver.MigrateVD, driver.ReplicaVD,
                         driver.ConsistencyGroupVD,
                         driver.CloneableVD, driver.CloneableImageVD,
-                        driver.RetypeVD,
                         driver.TransferVD):
     """IBM Storwize V7000 and SVC iSCSI/FC volume driver.
 

cinder/volume/drivers/ibm/xiv_ds8k.py

@@ -67,7 +67,6 @@ class XIVDS8KDriver(san.SanDriver,
                     driver.ConsistencyGroupVD,
                     driver.CloneableVD,
                     driver.CloneableImageVD,
-                    driver.RetypeVD,
                     driver.TransferVD):
     """Unified IBM XIV and DS8K volume driver."""
 

cinder/volume/drivers/rbd.py

@@ -264,7 +264,7 @@ class RADOSClient(object):
         return int(features)
 
 
-class RBDDriver(driver.RetypeVD, driver.TransferVD, driver.ExtendVD,
+class RBDDriver(driver.TransferVD, driver.ExtendVD,
                 driver.CloneableVD, driver.CloneableImageVD, driver.SnapshotVD,
                 driver.BaseVD):
     """Implements RADOS block device (RBD) volume commands."""

cinder/volume/drivers/san/hp/hp_lefthand_iscsi.py

@@ -50,7 +50,6 @@ class HPLeftHandISCSIDriver(driver.TransferVD,
                             driver.ExtendVD,
                             driver.CloneableVD,
                             driver.SnapshotVD,
-                            driver.RetypeVD,
                             driver.MigrateVD,
                             driver.BaseVD):
     """Executes commands relating to HP/LeftHand SAN ISCSI volumes.