Hyper-V: properly handle UNC instance paths

If the configured instances dir is an UNC path such as
\\ip\share\instances_dir, the HyperV driver fails to query the available
disk size, as it expects a path containing a drive letter.

Also, when attempting to move instance files during live migrations, it
will incorrectly try to build the remote path.

This change addresses those issues and is part of a bigger series,
attempting to fix HyperV shared storage related issues.

Change-Id: Ibdb9f7038bf5078867d64aef7fc63974ed8482af
Partial-Bug: #1565895

nova/tests/unit/virt/hyperv/test_hostops.py

@@ -44,6 +44,7 @@ class HostOpsTestCase(test_base.HyperVBaseTestCase):
         self._hostops = hostops.HostOps()
         self._hostops._hostutils = mock.MagicMock()
         self._hostops._pathutils = mock.MagicMock()
+        self._hostops._diskutils = mock.MagicMock()
 
     def test_get_cpu_info(self):
         mock_processors = mock.MagicMock()
@@ -90,13 +91,14 @@ class HostOpsTestCase(test_base.HyperVBaseTestCase):
         self._hostops._hostutils.get_memory_info.assert_called_once_with()
         self.assertEqual((2, 1, 1), response)
 
-    def test_get_local_hdd_info_gb(self):
+    def test_get_storage_info_gb(self):
         self._hostops._pathutils.get_instances_dir.return_value = ''
-        self._hostops._hostutils.get_volume_info.return_value = (2 * units.Gi,
-                                                                 1 * units.Gi)
-        response = self._hostops._get_local_hdd_info_gb()
+        self._hostops._diskutils.get_disk_capacity.return_value = (
+            2 * units.Gi, 1 * units.Gi)
+
+        response = self._hostops._get_storage_info_gb()
         self._hostops._pathutils.get_instances_dir.assert_called_once_with()
-        self._hostops._hostutils.get_volume_info.assert_called_once_with('')
+        self._hostops._diskutils.get_disk_capacity.assert_called_once_with('')
         self.assertEqual((2, 1, 1), response)
 
     def test_get_hypervisor_version(self):
@@ -135,16 +137,16 @@ class HostOpsTestCase(test_base.HyperVBaseTestCase):
     @mock.patch.object(hostops.HostOps, '_get_cpu_info')
     @mock.patch.object(hostops.HostOps, '_get_memory_info')
     @mock.patch.object(hostops.HostOps, '_get_hypervisor_version')
-    @mock.patch.object(hostops.HostOps, '_get_local_hdd_info_gb')
+    @mock.patch.object(hostops.HostOps, '_get_storage_info_gb')
     @mock.patch('platform.node')
     def test_get_available_resource(self, mock_node,
-                                    mock_get_local_hdd_info_gb,
+                                    mock_get_storage_info_gb,
                                     mock_get_hypervisor_version,
                                     mock_get_memory_info, mock_get_cpu_info,
                                     mock_get_gpu_info):
-        mock_get_local_hdd_info_gb.return_value = (mock.sentinel.LOCAL_GB,
-                                                   mock.sentinel.LOCAL_GB_FREE,
-                                                   mock.sentinel.LOCAL_GB_USED)
+        mock_get_storage_info_gb.return_value = (mock.sentinel.LOCAL_GB,
+                                                 mock.sentinel.LOCAL_GB_FREE,
+                                                 mock.sentinel.LOCAL_GB_USED)
         mock_get_memory_info.return_value = (mock.sentinel.MEMORY_MB,
                                              mock.sentinel.MEMORY_MB_FREE,
                                              mock.sentinel.MEMORY_MB_USED)

nova/tests/unit/virt/hyperv/test_pathutils.py

@@ -72,6 +72,44 @@ class PathUtilsTestCase(test_base.HyperVBaseTestCase):
             self.fake_instance_name)
         self.assertIsNone(configdrive_path)
 
+    def test_get_instances_dir_local(self):
+        self.flags(instances_path=self.fake_instance_dir)
+        instances_dir = self._pathutils.get_instances_dir()
+
+        self.assertEqual(self.fake_instance_dir, instances_dir)
+
+    def test_get_instances_dir_remote_instance_share(self):
+        # The Hyper-V driver allows using a pre-configured share exporting
+        # the instances dir. The same share name should be used across nodes.
+        fake_instances_dir_share = 'fake_instances_dir_share'
+        fake_remote = 'fake_remote'
+        expected_instance_dir = r'\\%s\%s' % (fake_remote,
+                                              fake_instances_dir_share)
+
+        self.flags(instances_path_share=fake_instances_dir_share,
+                   group='hyperv')
+        instances_dir = self._pathutils.get_instances_dir(
+            remote_server=fake_remote)
+        self.assertEqual(expected_instance_dir, instances_dir)
+
+    def test_get_instances_dir_administrative_share(self):
+        self.flags(instances_path=r'C:\fake_instance_dir')
+        fake_remote = 'fake_remote'
+        expected_instance_dir = r'\\fake_remote\C$\fake_instance_dir'
+
+        instances_dir = self._pathutils.get_instances_dir(
+            remote_server=fake_remote)
+        self.assertEqual(expected_instance_dir, instances_dir)
+
+    def test_get_instances_dir_unc_path(self):
+        fake_instance_dir = r'\\fake_addr\fake_share\fake_instance_dir'
+        self.flags(instances_path=fake_instance_dir)
+        fake_remote = 'fake_remote'
+
+        instances_dir = self._pathutils.get_instances_dir(
+            remote_server=fake_remote)
+        self.assertEqual(fake_instance_dir, instances_dir)
+
     @mock.patch('os.path.join')
     def test_get_instances_sub_dir(self, fake_path_join):
 

nova/virt/hyperv/hostops.py

@@ -17,7 +17,6 @@
 Management class for host operations.
 """
 import datetime
-import os
 import platform
 import time
 
@@ -41,6 +40,7 @@ LOG = logging.getLogger(__name__)
 
 class HostOps(object):
     def __init__(self):
+        self._diskutils = utilsfactory.get_diskutils()
         self._hostutils = utilsfactory.get_hostutils()
         self._pathutils = pathutils.PathUtils()
 
@@ -80,9 +80,10 @@ class HostOps(object):
         free_mem_mb = free_mem_kb // 1024
         return (total_mem_mb, free_mem_mb, total_mem_mb - free_mem_mb)
 
-    def _get_local_hdd_info_gb(self):
-        drive = os.path.splitdrive(self._pathutils.get_instances_dir())[0]
-        (size, free_space) = self._hostutils.get_volume_info(drive)
+    def _get_storage_info_gb(self):
+        instances_dir = self._pathutils.get_instances_dir()
+        (size, free_space) = self._diskutils.get_disk_capacity(
+            instances_dir)
 
         total_gb = size // units.Gi
         free_gb = free_space // units.Gi
@@ -138,7 +139,7 @@ class HostOps(object):
 
         (total_hdd_gb,
          free_hdd_gb,
-         used_hdd_gb) = self._get_local_hdd_info_gb()
+         used_hdd_gb) = self._get_storage_info_gb()
 
         cpu_info = self._get_cpu_info()
         cpu_topology = cpu_info['topology']

nova/virt/hyperv/pathutils.py

@@ -38,7 +38,7 @@ class PathUtils(pathutils.PathUtils):
     def get_instances_dir(self, remote_server=None):
         local_instance_path = os.path.normpath(CONF.instances_path)
 
-        if remote_server:
+        if remote_server and not local_instance_path.startswith(r'\\'):
             if CONF.hyperv.instances_path_share:
                 path = CONF.hyperv.instances_path_share
             else: