Implement revert_to_snapshot() for StorPool.

Use the StorPool API to revert a volume to the specified snapshot
immediately, without deleting and recreating the volume. This also
preserves the volume's metadata, such as e.g. SCSI WWN identifier for
the purposes of recognizing it on VM instances that it has been
previously attached to.

Change-Id: I3b8126cf1706921eac9556add11c558d973cf272
Implements: blueprint storpool-revert-to-snapshot

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

@@ -140,6 +140,16 @@ class MockAPI(object):
                 volumes[new_name]['name'] = new_name
             del volumes[name]
 
+    def volumeRevert(self, name, data):
+        if name not in volumes:
+            raise MockApiError('No such volume {name}'.format(name=name))
+
+        snapname = data['toSnapshot']
+        if snapname not in snapshots:
+            raise MockApiError('No such snapshot {name}'.format(name=snapname))
+
+        volumes[name] = dict(snapshots[snapname])
+
 
 class MockAttachDB(object):
     def __init__(self, log):
@@ -155,6 +165,10 @@ class MockAttachDB(object):
         return snapshotName(vtype, vid)
 
 
+def MockVolumeRevertDesc(toSnapshot):
+    return {'toSnapshot': toSnapshot}
+
+
 def MockVolumeUpdateDesc(size):
     return {'size': size}
 
@@ -170,6 +184,7 @@ def MockSPConfig(section = 's01'):
 fakeStorPool.spapi.ApiError = MockApiError
 fakeStorPool.spconfig.SPConfig = MockSPConfig
 fakeStorPool.spopenstack.AttachDB = MockAttachDB
+fakeStorPool.sptypes.VolumeRevertDesc = MockVolumeRevertDesc
 fakeStorPool.sptypes.VolumeUpdateDesc = MockVolumeUpdateDesc
 
 
@@ -524,3 +539,51 @@ class StorPoolTestCase(test.TestCase):
                          self.driver.get_pool({
                              'volume_type': volume_type
                          }))
+
+    def test_volume_revert(self):
+        vol_id = 'rev1'
+        vol_name = volumeName(vol_id)
+        snap_id = 'rev-s1'
+        snap_name = snapshotName('snap', snap_id)
+
+        self.assertVolumeNames([])
+        self.assertDictEqual({}, volumes)
+        self.assertDictEqual({}, snapshots)
+
+        self.driver.create_volume({'id': vol_id, 'name': 'v1', 'size': 1,
+                                   'volume_type': None})
+        self.assertVolumeNames((vol_id,))
+        self.assertDictEqual({}, snapshots)
+
+        self.driver.create_snapshot({'id': snap_id, 'volume_id': vol_id})
+        self.assertVolumeNames((vol_id,))
+        self.assertListEqual([snap_name], sorted(snapshots.keys()))
+        self.assertDictEqual(volumes[vol_name], snapshots[snap_name])
+        self.assertIsNot(volumes[vol_name], snapshots[snap_name])
+
+        self.driver.extend_volume({'id': vol_id}, 2)
+        self.assertVolumeNames((vol_id,))
+        self.assertNotEqual(volumes[vol_name], snapshots[snap_name])
+
+        self.driver.revert_to_snapshot(None, {'id': vol_id}, {'id': snap_id})
+        self.assertVolumeNames((vol_id,))
+        self.assertDictEqual(volumes[vol_name], snapshots[snap_name])
+        self.assertIsNot(volumes[vol_name], snapshots[snap_name])
+
+        self.driver.delete_snapshot({'id': snap_id})
+        self.assertVolumeNames((vol_id,))
+        self.assertDictEqual({}, snapshots)
+
+        self.assertRaisesRegex(exception.VolumeBackendAPIException,
+                               'No such snapshot',
+                               self.driver.revert_to_snapshot, None,
+                               {'id': vol_id}, {'id': snap_id})
+
+        self.driver.delete_volume({'id': vol_id})
+        self.assertDictEqual({}, volumes)
+        self.assertDictEqual({}, snapshots)
+
+        self.assertRaisesRegex(exception.VolumeBackendAPIException,
+                               'No such volume',
+                               self.driver.revert_to_snapshot, None,
+                               {'id': vol_id}, {'id': snap_id})

cinder/volume/drivers/storpool.py

@@ -90,9 +90,10 @@ class StorPoolDriver(driver.VolumeDriver):
         1.2.2   - Reintroduce the driver into OpenStack Queens,
                   add ignore_errors to the internal _detach_volume() method
         1.2.3   - Advertise some more driver capabilities.
+        2.0.0   - Implement revert_to_snapshot().
     """
 
-    VERSION = '1.2.3'
+    VERSION = '2.0.0'
     CI_WIKI_NAME = 'StorPool_distributed_storage_CI'
 
     def __init__(self, *args, **kwargs):
@@ -423,3 +424,18 @@ class StorPoolDriver(driver.VolumeDriver):
                       '%(err)s',
                       {'tname': temp_name, 'oname': orig_name, 'err': e})
             return {'_name_id': new_volume['_name_id'] or new_volume['id']}
+
+    def revert_to_snapshot(self, context, volume, snapshot):
+        volname = self._attach.volumeName(volume['id'])
+        snapname = self._attach.snapshotName('snap', snapshot['id'])
+        try:
+            rev = sptypes.VolumeRevertDesc(toSnapshot=snapname)
+            self._attach.api().volumeRevert(volname, rev)
+        except spapi.ApiError as e:
+            LOG.error('StorPool revert_to_snapshot(): could not revert '
+                      'the %(vol_id)s volume to the %(snap_id)s snapshot: '
+                      '%(err)s',
+                      {'vol_id': volume['id'],
+                       'snap_id': snapshot['id'],
+                       'err': e})
+            raise self._backendException(e)

doc/source/reference/support-matrix.ini

@@ -953,7 +953,7 @@ driver.rbd=complete
 driver.rbd_iscsi=complete
 driver.sandstone=complete
 driver.seagate=missing
-driver.storpool=missing
+driver.storpool=complete
 driver.synology=missing
 driver.toyou_netstor=complete
 driver.toyou_netstor_tyds=missing

releasenotes/notes/storpool-revert-to-snapshot-a202358ee16ecb62.yaml

@@ -0,0 +1,5 @@
+---
+features:
+  - |
+    StorPool driver: implemented revert to snapshot, which happens
+    immediately i.e. without deleting and recreating the volume.