Remove AMI snapshot format special case

Note that this includes seemingly-unrelated test changes because we
were actually skipping the snapshot_running test for libvirt, which
has been a bug for years. In that test case, when we went to look
for image_meta.disk_format, that attribute was not set on the o.vo
object, which raised a NotImplementedError. That error is also checked
by the test to skip the test for drivers that do not support snapshot,
which meant that for libvirt, we haven't been running that case
beyond the point at which we create snapshot metadata and trip that
exception. Thus, once removing that, there are other mocks not in
place that are required for the test to actually run. So, this adds
mocks for qemu_img_info() calls that actually try to read the file on
disk, as well as the privsep chown() that attempts to run after.

Change-Id: Ie731045629f0899840a4680d21793a16ade9b98e
(cherry picked from commit d5a631b)
(cherry picked from commit 8c5929f)
(cherry picked from commit d2d3b2c)
(cherry picked from commit 77dfa4f)

nova/tests/unit/virt/libvirt/test_driver.py

@@ -9242,7 +9242,7 @@ def test_unquiesce(self, mock_has_min_version):
 
     def test_create_snapshot_metadata(self):
         base = objects.ImageMeta.from_dict(
-            {'disk_format': 'raw'})
+            {'disk_format': 'qcow2'})
         instance_data = {'kernel_id': 'kernel',
                     'project_id': 'prj_id',
                     'ramdisk_id': 'ram_id',
@@ -9274,10 +9274,12 @@ def test_create_snapshot_metadata(self):
             {'disk_format': 'ami',
              'container_format': 'test_container'})
         expected['properties']['os_type'] = instance['os_type']
-        expected['disk_format'] = base.disk_format
+        # The disk_format of the snapshot should be the *actual* format of the
+        # thing we upload, regardless of what type of image we booted from.
+        expected['disk_format'] = img_fmt
         expected['container_format'] = base.container_format
         ret = drvr._create_snapshot_metadata(base, instance, img_fmt, snp_name)
-        self.assertEqual(ret, expected)
+        self.assertEqual(expected, ret)
 
     def test_get_volume_driver(self):
         conn = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
@@ -28778,7 +28780,8 @@ def test_ami(self):
           utils.get_system_metadata_from_image(
             {'disk_format': 'ami'})
 
-        self._test_snapshot(disk_format='ami')
+        # If we're uploading a qcow2, we must set the disk_format as such
+        self._test_snapshot(disk_format='qcow2')
 
     @mock.patch('nova.virt.libvirt.utils.get_disk_type_from_path',
                 new=mock.Mock(return_value=None))

nova/tests/unit/virt/test_virt_drivers.py

@@ -838,6 +838,11 @@ def setUp(self):
         # since we don't care about it.
         self.stub_out('os_vif.unplug', lambda a, kw: None)
         self.stub_out('nova.compute.utils.get_machine_ips', lambda: [])
+        self.stub_out('nova.virt.libvirt.utils.get_disk_size',
+                      lambda *a, **k: 123456)
+        self.stub_out('nova.virt.libvirt.utils.get_disk_backing_file',
+                      lambda *a, **k: None)
+        self.stub_out('nova.privsep.path.chown', lambda *a, **k: None)
 
     def test_init_host_image_type_rbd_force_raw_images_true(self):
         CONF.set_override('images_type', 'rbd', group='libvirt')

nova/virt/libvirt/driver.py

@@ -2938,11 +2938,7 @@ def _create_snapshot_metadata(self, image_meta, instance,
         if instance.os_type:
             metadata['properties']['os_type'] = instance.os_type
 
-        # NOTE(vish): glance forces ami disk format to be ami
-        if image_meta.disk_format == 'ami':
-            metadata['disk_format'] = 'ami'
-        else:
-            metadata['disk_format'] = img_fmt
+        metadata['disk_format'] = img_fmt
 
         if image_meta.obj_attr_is_set("container_format"):
             metadata['container_format'] = image_meta.container_format