From 842b39e2e8e73ea2dda84955d3ab99d9efbfa527 Mon Sep 17 00:00:00 2001
From: Peter Penchev <openstack-dev@storpool.com>
Date: Wed, 20 Apr 2022 15:47:39 +0300
Subject: [PATCH 07/10] StorPool: create_cloned_volume() improvements

If the source and destination volumes are in the same StorPool template
(as defined by either the volume type or the global config setting),
forego the need to create the transient snapshot at all and use
StorPool's "base this volume on that one" API call (which does the same
thing internally, but much more efficiently and atomically).

If the destination volume should be in a different StorPool template,
then make sure that the transient snapshot is also in that template so
that, if other volumes are cloned from the same source volume later,
they can all use the same data underneath (the internal workings of
StorPool will detect that all those snapshots are exactly the same and
not duplicate any data in the destination template). This will avoid
data duplication, sometimes with drastic results.

Bump the minimum required version of the "storpool" third-party library
for snapshotUpdate(template=...) support.

Change-Id: Ib9bb76cf2e2f2b035b92e596b1ef185558b190d6
---
 .../unit/volume/drivers/test_storpool.py      | 150 ++++++++++++++++--
 cinder/volume/drivers/storpool.py             |  84 ++++++++--
 driver-requirements.txt                       |   2 +-
 ...torpool-clone-better-dca90f40c9273de9.yaml |   6 +
 4 files changed, 208 insertions(+), 34 deletions(-)
 create mode 100644 releasenotes/notes/storpool-clone-better-dca90f40c9273de9.yaml

diff --git a/cinder/tests/unit/volume/drivers/test_storpool.py b/cinder/tests/unit/volume/drivers/test_storpool.py
index 24715fa29..95a1ffffd 100644
--- a/cinder/tests/unit/volume/drivers/test_storpool.py
+++ b/cinder/tests/unit/volume/drivers/test_storpool.py
@@ -14,6 +14,7 @@
 #    under the License.
 
 
+import itertools
 import re
 import sys
 from unittest import mock
@@ -110,13 +111,33 @@ class MockAPI(object):
     def snapshotCreate(self, vname, snap):
         snapshots[snap['name']] = dict(volumes[vname])
 
+    def snapshotUpdate(self, snap, data):
+        sdata = snapshots[snap]
+        sdata.update(data)
+
     def snapshotDelete(self, name):
         del snapshots[name]
 
     def volumeCreate(self, v):
-        if v['name'] in volumes:
+        name = v['name']
+        if name in volumes:
             raise MockApiError('volume already exists')
-        volumes[v['name']] = v
+        data = dict(v)
+
+        if 'parent' in v and 'template' not in v:
+            sdata = snapshots[v['parent']]
+            if 'template' in sdata:
+                data['template'] = sdata['template']
+
+        if 'baseOn' in v and 'template' not in v:
+            vdata = volumes[v['baseOn']]
+            if 'template' in vdata:
+                data['template'] = vdata['template']
+
+        if 'template' not in data:
+            data['template'] = None
+
+        volumes[name] = data
 
     def volumeDelete(self, name):
         del volumes[name]
@@ -174,6 +195,23 @@ fakeStorPool.spopenstack.AttachDB = MockAttachDB
 fakeStorPool.sptypes.VolumeUpdateDesc = MockVolumeUpdateDesc
 
 
+class MockVolumeDB(object):
+    """Simulate a Cinder database with a volume_get() method."""
+
+    def __init__(self, vol_types=None):
+        """Store the specified volume types mapping if necessary."""
+        self.vol_types = vol_types if vol_types is not None else {}
+
+    def volume_get(self, _context, vid):
+        """Get a volume-like structure, only the fields we care about."""
+        # Still, try to at least make sure we know about that volume
+        return {
+            'id': vid,
+            'size': volumes[volumeName(vid)]['size'],
+            'volume_type': self.vol_types.get(vid),
+        }
+
+
 @ddt.ddt
 class StorPoolTestCase(test.TestCase):
 
@@ -265,6 +303,11 @@ class StorPoolTestCase(test.TestCase):
         self.assertListEqual(sorted([volumeName(n) for n in names]),
                              sorted(data['name'] for data in volumes.values()))
 
+    def assertSnapshotNames(self, specs):
+        self.assertListEqual(
+            sorted(snapshotName(spec[0], spec[1]) for spec in specs),
+            sorted(snapshots.keys()))
+
     @mock_volume_types
     def test_create_delete_volume(self):
         self.assertVolumeNames([])
@@ -277,7 +320,7 @@ class StorPoolTestCase(test.TestCase):
         self.assertVolumeNames(('1',))
         v = volumes[volumeName('1')]
         self.assertEqual(1 * units.Gi, v['size'])
-        self.assertNotIn('template', v.keys())
+        self.assertIsNone(v['template'])
         self.assertEqual(3, v['replication'])
 
         caught = False
@@ -297,7 +340,7 @@ class StorPoolTestCase(test.TestCase):
         self.assertVolumeNames(('1',))
         v = volumes[volumeName('1')]
         self.assertEqual(2 * units.Gi, v['size'])
-        self.assertNotIn('template', v.keys())
+        self.assertIsNone(v['template'])
         self.assertEqual(3, v['replication'])
 
         self.driver.create_volume({'id': '2', 'name': 'v2', 'size': 3,
@@ -305,7 +348,7 @@ class StorPoolTestCase(test.TestCase):
         self.assertVolumeNames(('1', '2'))
         v = volumes[volumeName('2')]
         self.assertEqual(3 * units.Gi, v['size'])
-        self.assertNotIn('template', v.keys())
+        self.assertIsNone(v['template'])
         self.assertEqual(3, v['replication'])
 
         self.driver.create_volume({'id': '3', 'name': 'v2', 'size': 4,
@@ -327,7 +370,7 @@ class StorPoolTestCase(test.TestCase):
         # Make sure the dictionary is not corrupted somehow...
         v = volumes[volumeName('1')]
         self.assertEqual(2 * units.Gi, v['size'])
-        self.assertNotIn('template', v.keys())
+        self.assertIsNone(v['template'])
         self.assertEqual(3, v['replication'])
 
         for vid in ('1', '2', '3', '4'):
@@ -395,16 +438,17 @@ class StorPoolTestCase(test.TestCase):
         self.driver.extend_volume({'id': '1'}, 2)
         self.assertEqual(2 * units.Gi, volumes[volumeName('1')]['size'])
 
-        self.driver.create_cloned_volume({'id': '2', 'name': 'clo', 'size': 3},
-                                         {'id': 1})
+        with mock.patch.object(self.driver, 'db', new=MockVolumeDB()):
+            self.driver.create_cloned_volume(
+                {'id': '2', 'name': 'clo', 'size': 3, 'volume_type': None},
+                {'id': 1})
         self.assertVolumeNames(('1', '2'))
         self.assertDictEqual({}, snapshots)
-        # Note: this would not be true in a real environment (the snapshot will
-        # have been deleted, the volume would have no parent), but with this
-        # fake implementation it helps us make sure that the second volume was
-        # created with the proper options.
-        self.assertEqual(volumes[volumeName('2')]['parent'],
-                         snapshotName('clone', '2'))
+        # We do not provide a StorPool template name in either of the volumes'
+        # types, so create_cloned_volume() should take the baseOn shortcut.
+        vol2 = volumes[volumeName('2')]
+        self.assertEqual(vol2['baseOn'], volumeName('1'))
+        self.assertNotIn('parent', vol2)
 
         self.driver.delete_volume({'id': 1})
         self.driver.delete_volume({'id': 2})
@@ -412,6 +456,78 @@ class StorPoolTestCase(test.TestCase):
         self.assertDictEqual({}, volumes)
         self.assertDictEqual({}, snapshots)
 
+    @ddt.data(*itertools.product(
+        [None] + [{'id': key} for key in sorted(volume_types.keys())],
+        [None] + [{'id': key} for key in sorted(volume_types.keys())]))
+    @ddt.unpack
+    @mock_volume_types
+    def test_create_cloned_volume(self, src_type, dst_type):
+        self.assertDictEqual({}, volumes)
+        self.assertDictEqual({}, snapshots)
+
+        src_template = (
+            None
+            if src_type is None
+            else volume_types[src_type['id']].get('storpool_template')
+        )
+        dst_template = (
+            None
+            if dst_type is None
+            else volume_types[dst_type['id']].get('storpool_template')
+        )
+        src_name = 's-none' if src_template is None else 's-' + src_template
+        dst_name = 'd-none' if dst_template is None else 'd-' + dst_template
+
+        snap_name = snapshotName('clone', '2')
+
+        vdata1 = {
+            'id': '1',
+            'name': src_name,
+            'size': 1,
+            'volume_type': src_type,
+        }
+        self.assertEqual(
+            self.driver._template_from_volume(vdata1),
+            src_template)
+        self.driver.create_volume(vdata1)
+        self.assertVolumeNames(('1',))
+
+        vdata2 = {
+            'id': 2,
+            'name': dst_name,
+            'size': 1,
+            'volume_type': dst_type,
+        }
+        self.assertEqual(
+            self.driver._template_from_volume(vdata2),
+            dst_template)
+        with mock.patch.object(self.driver, 'db',
+                               new=MockVolumeDB(vol_types={'1': src_type})):
+            self.driver.create_cloned_volume(vdata2, {'id': '1'})
+        self.assertVolumeNames(('1', '2'))
+        vol2 = volumes[volumeName('2')]
+        self.assertEqual(vol2['template'], dst_template)
+
+        if src_template == dst_template:
+            self.assertEqual(vol2['baseOn'], volumeName('1'))
+            self.assertNotIn('parent', vol2)
+
+            self.assertDictEqual({}, snapshots)
+        else:
+            self.assertNotIn('baseOn', vol2)
+            self.assertEqual(vol2['parent'], snap_name)
+
+            self.assertSnapshotNames((('clone', '2'),))
+            self.assertEqual(snapshots[snap_name]['template'], dst_template)
+
+        self.driver.delete_volume({'id': '1'})
+        self.driver.delete_volume({'id': '2'})
+        if src_template != dst_template:
+            del snapshots[snap_name]
+
+        self.assertDictEqual({}, volumes)
+        self.assertDictEqual({}, snapshots)
+
     @mock_volume_types
     def test_config_replication(self):
         self.assertVolumeNames([])
@@ -431,7 +547,7 @@ class StorPoolTestCase(test.TestCase):
         self.assertVolumeNames(('cfgrepl1',))
         v = volumes[volumeName('cfgrepl1')]
         self.assertEqual(3, v['replication'])
-        self.assertNotIn('template', v)
+        self.assertIsNone(v['template'])
         self.driver.delete_volume({'id': 'cfgrepl1'})
 
         self.driver.configuration.storpool_replication = 2
@@ -445,7 +561,7 @@ class StorPoolTestCase(test.TestCase):
         self.assertVolumeNames(('cfgrepl2',))
         v = volumes[volumeName('cfgrepl2')]
         self.assertEqual(2, v['replication'])
-        self.assertNotIn('template', v)
+        self.assertIsNone(v['template'])
         self.driver.delete_volume({'id': 'cfgrepl2'})
 
         self.driver.create_volume({'id': 'cfgrepl3', 'name': 'v1', 'size': 1,
@@ -477,7 +593,7 @@ class StorPoolTestCase(test.TestCase):
         self.assertVolumeNames(('cfgtempl1',))
         v = volumes[volumeName('cfgtempl1')]
         self.assertEqual(3, v['replication'])
-        self.assertNotIn('template', v)
+        self.assertIsNone(v['template'])
         self.driver.delete_volume({'id': 'cfgtempl1'})
 
         self.driver.create_volume({'id': 'cfgtempl2', 'name': 'v1', 'size': 1,
diff --git a/cinder/volume/drivers/storpool.py b/cinder/volume/drivers/storpool.py
index 97d188fd4..5b4ea0d31 100644
--- a/cinder/volume/drivers/storpool.py
+++ b/cinder/volume/drivers/storpool.py
@@ -19,11 +19,13 @@ import platform
 
 from oslo_config import cfg
 from oslo_log import log as logging
+from oslo_utils import excutils
 from oslo_utils import importutils
 from oslo_utils import units
 import six
 
 from cinder.common import constants
+from cinder import context
 from cinder import exception
 from cinder.i18n import _
 from cinder import interface
@@ -197,30 +199,80 @@ class StorPoolDriver(driver.VolumeDriver):
 
     def create_cloned_volume(self, volume, src_vref):
         refname = self._attach.volumeName(src_vref['id'])
+        size = int(volume['size']) * units.Gi
+        volname = self._attach.volumeName(volume['id'])
+
+        src_volume = self.db.volume_get(
+            context.get_admin_context(),
+            src_vref['id'],
+        )
+        src_template = self._template_from_volume(src_volume)
+
+        template = self._template_from_volume(volume)
+        LOG.debug('clone volume id %(vol_id)r template %(template)r', {
+            'vol_id': volume['id'],
+            'template': template,
+        })
+        if template == src_template:
+            LOG.info('Using baseOn to clone a volume into the same template')
+            try:
+                self._attach.api().volumeCreate({
+                    'name': volname,
+                    'size': size,
+                    'baseOn': refname,
+                })
+            except spapi.ApiError as e:
+                raise self._backendException(e)
+
+            return None
+
         snapname = self._attach.snapshotName('clone', volume['id'])
+        LOG.info(
+            'A transient snapshot for a %(src)s -> %(dst)s template change',
+            {'src': src_template, 'dst': template})
         try:
             self._attach.api().snapshotCreate(refname, {'name': snapname})
         except spapi.ApiError as e:
-            raise self._backendException(e)
+            if e.name != 'objectExists':
+                raise self._backendException(e)
 
-        size = int(volume['size']) * units.Gi
-        volname = self._attach.volumeName(volume['id'])
         try:
-            self._attach.api().volumeCreate({
-                'name': volname,
-                'size': size,
-                'parent': snapname
-            })
-        except spapi.ApiError as e:
-            raise self._backendException(e)
-        finally:
             try:
-                self._attach.api().snapshotDelete(snapname)
+                self._attach.api().snapshotUpdate(
+                    snapname,
+                    {'template': template},
+                )
             except spapi.ApiError as e:
-                # ARGH!
-                LOG.error("Could not delete the temp snapshot %(name)s: "
-                          "%(msg)s",
-                          {'name': snapname, 'msg': e})
+                raise self._backendException(e)
+
+            try:
+                self._attach.api().volumeCreate({
+                    'name': volname,
+                    'size': size,
+                    'parent': snapname
+                })
+            except spapi.ApiError as e:
+                raise self._backendException(e)
+
+            try:
+                self._attach.api().snapshotUpdate(
+                    snapname,
+                    {'tags': {'transient': '1.0'}},
+                )
+            except spapi.ApiError as e:
+                raise self._backendException(e)
+        except Exception:
+            with excutils.save_and_reraise_exception():
+                try:
+                    LOG.warning(
+                        'Something went wrong, removing the transient snapshot'
+                    )
+                    self._attach.api().snapshotDelete(snapname)
+                except spapi.ApiError as e:
+                    LOG.error(
+                        'Could not delete the %(name)s snapshot: %(err)s',
+                        {'name': snapname, 'err': str(e)}
+                    )
 
     def create_export(self, context, volume, connector):
         pass
diff --git a/driver-requirements.txt b/driver-requirements.txt
index 2f05bc94e..2b28d37fd 100644
--- a/driver-requirements.txt
+++ b/driver-requirements.txt
@@ -41,7 +41,7 @@ infi.dtypes.wwn # PSF
 infi.dtypes.iqn # PSF
 
 # Storpool
-storpool>=4.0.0 # Apache-2.0
+storpool>=7.1.0 # Apache-2.0
 storpool.spopenstack>=2.2.1 # Apache-2.0
 
 # Datera
diff --git a/releasenotes/notes/storpool-clone-better-dca90f40c9273de9.yaml b/releasenotes/notes/storpool-clone-better-dca90f40c9273de9.yaml
new file mode 100644
index 000000000..9d512c831
--- /dev/null
+++ b/releasenotes/notes/storpool-clone-better-dca90f40c9273de9.yaml
@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    StorPool driver: improved the way volumes are cloned into different
+    StorPool templates (exposed as Cinder storage pools) if requested,
+    eliminating some data duplication in the underlying StorPool cluster.
-- 
2.42.0