RBD: Implement volume extension

The RBD connector doesn't implement the extend_volume method and raise
NotImplementedError when called.

This patch implements the method for all types of connected volumes:

- File descriptor
- OpenStack locally attached
- Non OpenStack locally attached

Closes-Bug: #1884554
Related-Bug: #1883720
Change-Id: I4bbf3778210d05c6934289116a85a8f344bed818

os_brick/initiator/connectors/rbd.py

@@ -384,5 +384,45 @@ class RBDConnector(base.BaseLinuxConnector):
         return self._check_valid_device(path)
 
     def extend_volume(self, connection_properties):
-        # TODO(walter-boring): is this possible?
-        raise NotImplementedError
+        """Refresh local volume view and return current size in bytes."""
+        # Nothing to do, RBD attached volumes are automatically refreshed, but
+        # we need to return the new size for compatibility
+        do_local_attach = connection_properties.get('do_local_attach',
+                                                    self.do_local_attach)
+
+        if not do_local_attach:
+            handle = self._get_rbd_handle(connection_properties)
+            try:
+                # Handles should return absolute position on seek, but the RBD
+                # wrapper doesn't, so we need to call tell afterwards
+                handle.seek(0, 2)
+                return handle.tell()
+            finally:
+                fileutils.delete_if_exists(handle.rbd_conf)
+                handle.close()
+
+        # Create config file when we do the attach on the host and not the VM
+        conf = self.create_non_openstack_config(connection_properties)
+
+        try:
+            device_path = self._find_root_device(connection_properties, conf)
+        finally:
+            # If we have generated the config file we need to remove it
+            if conf:
+                try:
+                    rbd_privsep.delete_if_exists(conf)
+                except Exception as exc:
+                    LOG.warning(_('Could not remove config file %(filename)s: '
+                                  '%(exc)s'), {'filename': conf, 'exc': exc})
+
+        if not device_path:
+            msg = _('Cannot extend non mapped device.')
+            raise exception.BrickException(msg=msg)
+
+        device_name = os.path.basename(device_path)  # ie: rbd0
+        device_number = device_name[3:]  # ie: 0
+        # Get size from /sys/devices/rbd/0/size instead of
+        # /sys/class/block/rbd0/size because the latter isn't updated
+        with open('/sys/devices/rbd/' + device_number + '/size') as f:
+            size_bytes = f.read().strip()
+        return int(size_bytes)

os_brick/tests/initiator/connectors/test_rbd.py

@@ -419,12 +419,72 @@ class RBDConnectorTestCase(test_connector.ConnectorTestCase):
         mock_execute.called_once_with(*show_cmd, root_helper=None,
                                       run_as_root=True)
 
-    def test_extend_volume(self):
-        rbd_connector = rbd.RBDConnector(None)
-        self.assertRaises(NotImplementedError,
-                          rbd_connector.extend_volume,
+    @mock.patch('oslo_utils.fileutils.delete_if_exists')
+    @mock.patch.object(rbd.RBDConnector, '_get_rbd_handle')
+    def test_extend_volume_handle(self, mock_handle, mock_delete):
+        connector = rbd.RBDConnector(None)
+        res = connector.extend_volume(self.connection_properties)
+
+        mock_handle.assert_called_once_with(self.connection_properties)
+        mock_handle.return_value.seek.assert_called_once_with(0, 2)
+        mock_handle.return_value.tell.assert_called_once_with()
+        self.assertIs(mock_handle().tell(), res)
+        mock_delete.assert_called_once_with(mock_handle().rbd_conf)
+        mock_handle.return_value.close.assert_called_once_with()
+
+    @mock.patch('oslo_utils.fileutils.delete_if_exists')
+    @mock.patch.object(rbd.RBDConnector, '_get_rbd_handle')
+    def test_extend_volume_handle_fail(self, mock_handle, mock_delete):
+        mock_handle.return_value.seek.side_effect = ValueError
+        connector = rbd.RBDConnector(None)
+
+        self.assertRaises(ValueError, connector.extend_volume,
                           self.connection_properties)
 
+        mock_handle.assert_called_once_with(self.connection_properties)
+        mock_handle.return_value.seek.assert_called_once_with(0, 2)
+        mock_handle().tell.assert_not_called()
+        mock_delete.assert_called_once_with(mock_handle.return_value.rbd_conf)
+        mock_handle.return_value.close.assert_called_once_with()
+
+    @mock.patch.object(rbd, 'open')
+    @mock.patch('os_brick.privileged.rbd.delete_if_exists')
+    @mock.patch.object(rbd.RBDConnector, '_find_root_device')
+    @mock.patch.object(rbd.RBDConnector, 'create_non_openstack_config')
+    def test_extend_volume_block(self, mock_config, mock_find, mock_delete,
+                                 mock_open):
+        mock_find.return_value = '/dev/rbd1'
+        file_handle = mock_open.return_value.__enter__.return_value
+        file_handle.read.return_value = '123456789'
+        connector = rbd.RBDConnector(None, do_local_attach=True)
+
+        res = connector.extend_volume(self.connection_properties)
+
+        mock_config.assert_called_once_with(self.connection_properties)
+        mock_find.assert_called_once_with(self.connection_properties,
+                                          mock_config.return_value)
+        mock_delete.assert_called_once_with(mock_config.return_value)
+        mock_open.assert_called_once_with('/sys/devices/rbd/1/size')
+        file_handle.read.assert_called_once_with()
+        self.assertEqual(123456789, res)
+
+    @mock.patch.object(rbd, 'open')
+    @mock.patch('os_brick.privileged.rbd.delete_if_exists')
+    @mock.patch.object(rbd.RBDConnector, '_find_root_device')
+    @mock.patch.object(rbd.RBDConnector, 'create_non_openstack_config')
+    def test_extend_volume_no_device_local(self, mock_config, mock_find,
+                                           mock_delete, mock_open):
+        mock_find.return_value = None
+        connector = rbd.RBDConnector(None, do_local_attach=True)
+        self.assertRaises(exception.BrickException, connector.extend_volume,
+                          self.connection_properties)
+
+        mock_config.assert_called_once_with(self.connection_properties)
+        mock_find.assert_called_once_with(self.connection_properties,
+                                          mock_config.return_value)
+        mock_delete.assert_called_once_with(mock_config.return_value)
+        mock_open.assert_not_called()
+
     def test__get_rbd_args(self):
         res = rbd.RBDConnector._get_rbd_args(self.connection_properties, None)
         expected = ['--id', self.user,

releasenotes/notes/rbd_extend_volume-5bc6adc08f662c5b.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    Implement the extend_volume method for the RBD connector.
+    (Bug #1884554).