linuxscsi: Stop waiting for multipath devices during extend_volume

Previously linuxscsi.extend_volume would always attempt to wait for
multipath devices to appear regardless of multipath actually being used
by the connector.

This change corrects this by passing down the existing use_multipath
attribute from the iSCSI and FC connectors into linuxscsi.extend_volume.
The same attribute is introduced to the NVMe connector to also allow it
to skip this search for multipath devices.

Change-Id: I29d65ae036957f3a63cba93dd330b14e3361a1b9
Closes-bug: #1832247

os_brick/initiator/connectors/fibre_channel.py

@@ -176,7 +176,8 @@ class FibreChannelConnector(base.BaseLinuxConnector):
 
         volume_paths = self.get_volume_paths(connection_properties)
         if volume_paths:
-            return self._linuxscsi.extend_volume(volume_paths)
+            return self._linuxscsi.extend_volume(
+                volume_paths, use_multipath=self.use_multipath)
         else:
             LOG.warning("Couldn't find any volume paths on the host to "
                         "extend volume for %(props)s",

os_brick/initiator/connectors/iscsi.py

@@ -474,7 +474,8 @@ class ISCSIConnector(base.BaseLinuxConnector, base_iscsi.BaseISCSIConnector):
         volume_paths = self.get_volume_paths(connection_properties)
         LOG.info("Found paths for volume %s", volume_paths)
         if volume_paths:
-            return self._linuxscsi.extend_volume(volume_paths)
+            return self._linuxscsi.extend_volume(
+                volume_paths, use_multipath=self.use_multipath)
         else:
             LOG.warning("Couldn't find any volume paths on the host to "
                         "extend volume for %(props)s",

os_brick/initiator/connectors/nvme.py

@@ -34,7 +34,7 @@ class NVMeConnector(base.BaseLinuxConnector):
 
     """Connector class to attach/detach NVMe over fabric volumes."""
 
-    def __init__(self, root_helper, driver=None,
+    def __init__(self, root_helper, driver=None, use_multipath=False,
                  device_scan_attempts=DEVICE_SCAN_ATTEMPTS_DEFAULT,
                  *args, **kwargs):
         super(NVMeConnector, self).__init__(
@@ -42,6 +42,7 @@ class NVMeConnector(base.BaseLinuxConnector):
             driver=driver,
             device_scan_attempts=device_scan_attempts,
             *args, **kwargs)
+        self.use_multipath = use_multipath
 
     def _get_system_uuid(self):
         # RSD requires system_uuid to let Cinder RSD Driver identify
@@ -226,7 +227,8 @@ class NVMeConnector(base.BaseLinuxConnector):
         """
         volume_paths = self.get_volume_paths(connection_properties)
         if volume_paths:
-            return self._linuxscsi.extend_volume(volume_paths)
+            return self._linuxscsi.extend_volume(
+                volume_paths, use_multipath=self.use_multipath)
         else:
             LOG.warning("Couldn't find any volume paths on the host to "
                         "extend volume for %(props)s",

os_brick/initiator/linuxscsi.py

@@ -531,7 +531,7 @@ class LinuxSCSI(executor.Executor):
                                     root_helper=self._root_helper)
         return out
 
-    def extend_volume(self, volume_paths):
+    def extend_volume(self, volume_paths, use_multipath=False):
         """Signal the SCSI subsystem to test for volume resize.
 
         This function tries to signal the local system's kernel
@@ -561,24 +561,26 @@ class LinuxSCSI(executor.Executor):
             LOG.debug("volume size after scsi device rescan %s", new_size)
 
         scsi_wwn = self.get_scsi_wwn(volume_paths[0])
-        mpath_device = self.find_multipath_device_path(scsi_wwn)
-        if mpath_device:
-            # Force a reconfigure so that resize works
-            self.multipath_reconfigure()
+        if use_multipath:
+            mpath_device = self.find_multipath_device_path(scsi_wwn)
+            if mpath_device:
+                # Force a reconfigure so that resize works
+                self.multipath_reconfigure()
 
-            size = self.get_device_size(mpath_device)
-            LOG.info("mpath(%(device)s) current size %(size)s",
-                     {'device': mpath_device, 'size': size})
-            result = self.multipath_resize_map(scsi_wwn)
-            if 'fail' in result:
-                LOG.error("Multipathd failed to update the size mapping of "
-                          "multipath device %(scsi_wwn)s volume %(volume)s",
-                          {'scsi_wwn': scsi_wwn, 'volume': volume_paths})
-                return None
+                size = self.get_device_size(mpath_device)
+                LOG.info("mpath(%(device)s) current size %(size)s",
+                         {'device': mpath_device, 'size': size})
+                result = self.multipath_resize_map(scsi_wwn)
+                if 'fail' in result:
+                    LOG.error("Multipathd failed to update the size mapping "
+                              "of multipath device %(scsi_wwn)s volume "
+                              "%(volume)s",
+                              {'scsi_wwn': scsi_wwn, 'volume': volume_paths})
+                    return None
 
-            new_size = self.get_device_size(mpath_device)
-            LOG.info("mpath(%(device)s) new size %(size)s",
-                     {'device': mpath_device, 'size': new_size})
+                new_size = self.get_device_size(mpath_device)
+                LOG.info("mpath(%(device)s) new size %(size)s",
+                         {'device': mpath_device, 'size': new_size})
 
         return new_size
 

os_brick/tests/initiator/connectors/test_nvme.py

@@ -38,7 +38,8 @@ class NVMeConnectorTestCase(test_connector.ConnectorTestCase):
     def setUp(self):
         super(NVMeConnectorTestCase, self).setUp()
         self.connector = nvme.NVMeConnector(None,
-                                            execute=self.fake_execute)
+                                            execute=self.fake_execute,
+                                            use_multipath=False)
 
     @mock.patch.object(nvme.NVMeConnector, '_execute')
     def test_get_sysuuid_without_newline(self, mock_execute):
@@ -284,9 +285,11 @@ class NVMeConnectorTestCase(test_connector.ConnectorTestCase):
                           self.connector.extend_volume,
                           connection_properties)
 
+    @mock.patch.object(linuxscsi.LinuxSCSI, 'find_multipath_device_path')
     @mock.patch.object(linuxscsi.LinuxSCSI, 'extend_volume')
     @mock.patch.object(nvme.NVMeConnector, 'get_volume_paths')
-    def test_extend_volume(self, mock_volume_paths, mock_scsi_extend):
+    def test_extend_volume(self, mock_volume_paths, mock_scsi_extend,
+                           mock_scsi_find_mpath):
         fake_new_size = 1024
         mock_volume_paths.return_value = ['/dev/vdx']
         mock_scsi_extend.return_value = fake_new_size
@@ -297,3 +300,4 @@ class NVMeConnectorTestCase(test_connector.ConnectorTestCase):
                                  'transport_type': 'rdma'}
         new_size = self.connector.extend_volume(connection_properties)
         self.assertEqual(fake_new_size, new_size)
+        mock_scsi_find_mpath.assert_not_called()

os_brick/tests/initiator/test_linuxscsi.py

@@ -761,7 +761,8 @@ loop0                                     0"""
         mock_find_mpath_path.return_value = ('/dev/mapper/dm-uuid-mpath-%s' %
                                              wwn)
 
-        ret_size = self.linuxscsi.extend_volume(['/dev/fake1', '/dev/fake2'])
+        ret_size = self.linuxscsi.extend_volume(['/dev/fake1', '/dev/fake2'],
+                                                use_multipath=True)
         self.assertEqual(2048, ret_size)
 
         # because we don't mock out the echo_scsi_command
@@ -795,7 +796,8 @@ loop0                                     0"""
 
         mock_mpath_resize_map.return_value = 'fail'
 
-        ret_size = self.linuxscsi.extend_volume(['/dev/fake1', '/dev/fake2'])
+        ret_size = self.linuxscsi.extend_volume(['/dev/fake1', '/dev/fake2'],
+                                                use_multipath=True)
         self.assertIsNone(ret_size)
 
         # because we don't mock out the echo_scsi_command