RBD: Fix _show_msg_check_clone_v2_api

There might be a case where the exception raised by `op_features`
could be other than AttributeError. When any exception other than
AttributeError is raised, we should log and avoid raising an
exception.

Closes-Bug: #1942210
Co-Authored-By: Gorka Eguileor <geguileo@redhat.com>
Change-Id: I513abe980b73d7e7b1a3cd9c7ff89490f7fd6b08

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

@@ -117,6 +117,9 @@ def common_mocks(f):
             inst.mock_rbd.PermissionError = MockPermissionError
 
             inst.driver.rbd = inst.mock_rbd
+            aux = inst.driver.rbd
+            aux.Image.return_value.stripe_unit.return_value = 4194304
+
             inst.driver.rados = inst.mock_rados
             return f(inst, *args, **kwargs)
 
@@ -1102,6 +1105,29 @@ class RBDTestCase(test.TestCase):
         flatten_mock.assert_called_once_with(self.cfg.rbd_pool,
                                              self.volume_a.name)
 
+    @common_mocks
+    @mock.patch('cinder.objects.Volume.get_by_id')
+    @mock.patch.object(driver.RBDDriver, '_resize', mock.Mock())
+    def test_log_create_vol_from_snap_raise(self, volume_get_by_id):
+        volume_get_by_id.return_value = self.volume_a
+
+        self.mock_proxy().__enter__().volume.op_features.side_effect = \
+            Exception
+        self.mock_rbd.RBD_OPERATION_FEATURE_CLONE_PARENT = 1
+
+        snapshot = self.snapshot
+        self.cfg.rbd_flatten_volume_from_snapshot = False
+
+        with mock.patch.object(driver, 'LOG') as mock_log:
+            # Fist call
+            self.driver.create_volume_from_snapshot(self.volume_a, snapshot)
+            self.assertTrue(self.driver._clone_v2_api_checked)
+            # Second call
+            self.driver.create_volume_from_snapshot(self.volume_a, snapshot)
+            # Check that that the second call to create_volume_from_snapshot
+            # doesn't log anything
+            mock_log.warning.assert_called_once_with(mock.ANY)
+
     @common_mocks
     @mock.patch('cinder.objects.Volume.get_by_id')
     def test_delete_snapshot(self, volume_get_by_id):

cinder/volume/drivers/rbd.py

@@ -328,16 +328,17 @@ class RBDDriver(driver.CloneableImageVD, driver.MigrateVD,
             self._clone_v2_api_checked = True
             with RBDVolumeProxy(self, volume_name, read_only=True) as volume:
                 try:
-                    if (volume.volume.op_features() &
-                            self.rbd.RBD_OPERATION_FEATURE_CLONE_PARENT):
-                        LOG.info('Using v2 Clone API')
-                        return
-                except AttributeError:
-                    pass
-                LOG.warning('Not using v2 clone API, please upgrade to'
-                            ' mimic+ and set the OSD minimum client'
-                            ' compat version to mimic for better'
-                            ' performance, fewer deletion issues')
+                    enabled = (volume.volume.op_features() &
+                               self.rbd.RBD_OPERATION_FEATURE_CLONE_PARENT)
+                except Exception:
+                    enabled = False
+                if enabled:
+                    LOG.info('Using v2 Clone API')
+                else:
+                    LOG.warning('Not using v2 clone API, please upgrade to'
+                                ' mimic+ and set the OSD minimum client'
+                                ' compat version to mimic for better'
+                                ' performance, fewer deletion issues')
 
     def _get_target_config(self,
                            target_id: Optional[str]) -> Dict[str,

releasenotes/notes/bug-1942210-show-msg-check-clone-v2-api-raise-attribute-error-40efd74bb92b9482.yaml

@@ -0,0 +1,10 @@
+---
+fixes:
+  - |
+    RBD driver `bug #1942210
+    <https://bugs.launchpad.net/cinder/+bug/1942210>`_: When
+    creating a volume from a snapshot, the operation could
+    fail due to an uncaught exception being raised during a
+    check to see if the backend Ceph installation supported
+    the clone v2 API.  The driver now handles this situation
+    gracefully.