From d7b831e38cbc029b7975d1059ed212762a5f6a5e Mon Sep 17 00:00:00 2001
From: Chris Friesen <chris.friesen@windriver.com>
Date: Fri, 22 Jul 2016 16:33:43 -0600
Subject: [PATCH] Fix cold migration with qcow2 ephemeral disks

If we have qcow2 ephemeral disks we need to ensure that the
backing file gets created on a cold migration.

This requires passing in the block_device_info when calling
_create_image() so that we can loop over the ephemeral disks.

Closes-Bug: #1605720
Co-Authored-By: Feodor Tersin <ftersin@hotmail.com>
Change-Id: Ie278bb10e1675ba1d903aaa3c0249be0d1cf147b
---

diff --git a/nova/tests/unit/virt/libvirt/fake_imagebackend.py b/nova/tests/unit/virt/libvirt/fake_imagebackend.py
index ba3b2a4..d92e5a3 100644
--- a/nova/tests/unit/virt/libvirt/fake_imagebackend.py
+++ b/nova/tests/unit/virt/libvirt/fake_imagebackend.py
@@ -138,7 +138,7 @@
             # Used directly by callers. These would have been set if called
             # the real constructor.
             setattr(disk, 'path', path)
-            setattr(disk, 'is_block_dev', False)
+            setattr(disk, 'is_block_dev', mock.sentinel.is_block_dev)
 
             # Used by tests. Note that image_init is a closure over image_type.
             setattr(disk, 'image_type', image_type)
diff --git a/nova/tests/unit/virt/libvirt/test_driver.py b/nova/tests/unit/virt/libvirt/test_driver.py
index 653ee7f..6290f4a 100644
--- a/nova/tests/unit/virt/libvirt/test_driver.py
+++ b/nova/tests/unit/virt/libvirt/test_driver.py
@@ -19,6 +19,7 @@
 import copy
 import datetime
 import errno
+import functools
 import glob
 import os
 import random
@@ -10523,7 +10524,7 @@
 
         return gotFiles, imported_files
 
-    def test_create_image_with_swap(self):
+    def test_create_image_with_flavor_swap(self):
         def enable_swap(instance_ref):
             # Turn on some swap to exercise that codepath in _create_image
             instance_ref['system_metadata']['instance_type_swap'] = 500
@@ -10554,6 +10555,52 @@
         self.assertTrue(imported_files[0][0].endswith('/disk.config'))
         self.assertEqual('disk.config', imported_files[0][1])
 
+    def test_create_image_with_swap(self):
+        drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
+        instance_ref = self.test_instance
+        instance_ref['image_ref'] = ''
+        instance = objects.Instance(**instance_ref)
+        # Also check that bdm specified swap takes precedence over flavor
+        # specified swap
+        instance.flavor.swap = 200
+        image_meta = objects.ImageMeta.from_dict(self.test_image_meta)
+        bdi = {'swap': {'swap_size': 100,
+                        'device_name': '/dev/vdb'},
+               'block_device_mapping': [{'boot_index': 0}]}
+        disk_info = blockinfo.get_disk_info(CONF.libvirt.virt_type,
+                                            instance, image_meta,
+                                            block_device_info=bdi)
+        backend = self.useFixture(fake_imagebackend.ImageBackendFixture())
+
+        drvr._create_image(self.context, instance, disk_info['mapping'],
+                           block_device_info=bdi)
+
+        backend.disks['disk.swap'].cache.assert_called_once_with(
+            fetch_func=drvr._create_swap, context=self.context,
+            filename='swap_100', size=100 * units.Mi, swap_mb=100)
+
+    def test_create_image_with_legacy_swap_resizing(self):
+        drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
+        instance_ref = self.test_instance
+        instance_ref['image_ref'] = ''
+        instance = objects.Instance(**instance_ref)
+        instance.flavor.swap = 200
+        image_meta = objects.ImageMeta.from_dict(self.test_image_meta)
+        bdi = {'swap': {'swap_size': 100,
+                        'device_name': '/dev/vdb'},
+               'block_device_mapping': [{'boot_index': 0}]}
+        disk_info = blockinfo.get_disk_info(CONF.libvirt.virt_type,
+                                            instance, image_meta,
+                                            block_device_info=bdi)
+        backend = self.useFixture(fake_imagebackend.ImageBackendFixture())
+
+        drvr._create_image(self.context, instance, disk_info['mapping'],
+                           block_device_info=bdi, ignore_bdi_for_swap=True)
+
+        backend.disks['disk.swap'].cache.assert_called_once_with(
+            fetch_func=drvr._create_swap, context=self.context,
+            filename='swap_200', size=200 * units.Mi, swap_mb=200)
+
     @mock.patch.object(nova.virt.libvirt.imagebackend.Image, 'cache',
                        side_effect=exception.ImageNotFound(image_id='fake-id'))
     def test_create_image_not_exist_no_fallback(self, mock_cache):
@@ -10597,6 +10644,37 @@
                                               host='fake-source-host',
                                               receive=True)
 
+    @mock.patch('nova.virt.disk.api.get_file_extension_for_os_type')
+    def test_create_image_with_ephemerals(self, mock_get_ext):
+        drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
+        instance_ref = self.test_instance
+        instance_ref['image_ref'] = ''
+        instance = objects.Instance(**instance_ref)
+        image_meta = objects.ImageMeta.from_dict(self.test_image_meta)
+        bdi = {'ephemerals': [{'size': 100}],
+               'block_device_mapping': [{'boot_index': 0}]}
+        disk_info = blockinfo.get_disk_info(CONF.libvirt.virt_type,
+                                            instance, image_meta,
+                                            block_device_info=bdi)
+        mock_get_ext.return_value = mock.sentinel.file_ext
+        backend = self.useFixture(fake_imagebackend.ImageBackendFixture())
+
+        drvr._create_image(self.context, instance, disk_info['mapping'],
+                           block_device_info=bdi)
+
+        backend.disks['disk.eph0'].cache.assert_called_once_with(
+            fetch_func=mock.ANY, context=self.context,
+            filename=('ephemeral_100_%s' % mock.sentinel.file_ext),
+            size=100 * units.Gi, ephemeral_size=100, specified_fs=None)
+        fetch_func = (backend.disks['disk.eph0'].cache.
+                      mock_calls[0][2]['fetch_func'])
+        self.assertIsInstance(fetch_func, functools.partial)
+        self.assertEqual(drvr._create_ephemeral, fetch_func.func)
+        self.assertEqual(
+            dict(fs_label='ephemeral0', os_type=instance.os_type,
+                 is_block_dev=mock.sentinel.is_block_dev),
+            fetch_func.keywords)
+
     @mock.patch.object(nova.virt.libvirt.imagebackend.Image, 'cache')
     def test_create_image_resize_snap_backend(self, mock_cache):
         drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
@@ -15579,6 +15657,7 @@
         self.fake_create_domain_called = False
         self.fake_disk_resize_called = False
         create_image_called = [False]
+        bdi = {'block_device_mapping': []}
 
         def fake_to_xml(context, instance, network_info, disk_info,
                         image_meta=None, rescue=None,
@@ -15592,8 +15671,11 @@
                               disk_mapping, suffix='',
                               disk_images=None, network_info=None,
                               block_device_info=None, inject_files=True,
-                              fallback_from_host=None):
+                              fallback_from_host=None,
+                              ignore_bdi_for_swap=False):
+            self.assertTrue(ignore_bdi_for_swap)
             self.assertFalse(inject_files)
+            self.assertEqual(bdi, block_device_info)
             create_image_called[0] = True
 
         def fake_create_domain_and_network(
@@ -15660,7 +15742,7 @@
             self.drvr.finish_migration(
                           context.get_admin_context(), migration, instance,
                           disk_info, [], image_meta,
-                          resize_instance, None, power_on)
+                          resize_instance, bdi, power_on)
 
             mock_ensure_console_log.assert_called_once_with(instance)
 
diff --git a/nova/virt/libvirt/driver.py b/nova/virt/libvirt/driver.py
index 10bc929..5aebb99 100644
--- a/nova/virt/libvirt/driver.py
+++ b/nova/virt/libvirt/driver.py
@@ -2960,7 +2960,8 @@
                       disk_images=None, network_info=None,
                       block_device_info=None, files=None,
                       admin_pass=None, inject_files=True,
-                      fallback_from_host=None):
+                      fallback_from_host=None,
+                      ignore_bdi_for_swap=False):
         booted_from_volume = self._is_booted_from_volume(
             instance, disk_mapping)
 
@@ -3052,13 +3053,26 @@
             mapping = disk_mapping['disk.swap']
             swap_mb = 0
 
-            swap = driver.block_device_info_get_swap(block_device_info)
-            if driver.swap_is_usable(swap):
-                swap_mb = swap['swap_size']
-            elif (inst_type['swap'] > 0 and
-                  not block_device.volume_in_mapping(
-                    mapping['dev'], block_device_info)):
+            if ignore_bdi_for_swap:
+                # This is a workaround to support legacy swap resizing,
+                # which does not touch swap size specified in bdm,
+                # but works with flavor specified size only.
+                # In this case we follow the legacy logic and ignore block
+                # device info completely.
+                # NOTE(ft): This workaround must be removed when a correct
+                # implementation of resize operation changing sizes in bdms is
+                # developed. Also at that stage we probably may get rid of
+                # the direct usage of flavor swap size here,
+                # leaving the work with bdm only.
                 swap_mb = inst_type['swap']
+            else:
+                swap = driver.block_device_info_get_swap(block_device_info)
+                if driver.swap_is_usable(swap):
+                    swap_mb = swap['swap_size']
+                elif (inst_type['swap'] > 0 and
+                      not block_device.volume_in_mapping(
+                        mapping['dev'], block_device_info)):
+                    swap_mb = inst_type['swap']
 
             if swap_mb > 0:
                 size = swap_mb * units.Mi
@@ -7192,7 +7206,8 @@
         # backing file.
         self._create_image(context, instance, block_disk_info['mapping'],
                            network_info=network_info,
-                           block_device_info=None, inject_files=False,
+                           block_device_info=block_device_info,
+                           inject_files=False, ignore_bdi_for_swap=True,
                            fallback_from_host=migration.source_compute)
 
         # Required by Quobyte CI