libvirt: Get driver type from base image type.

If we are using the raw backend (no cow), we should set the driver
type based on the type of the source image instead of always
using raw.

Calls to to_xml were moved after _create_image so that the image
type could be determined when creating the xml for libvirt.

Fixes bug 1163009

Change-Id: Ic8d5f0ab83d868a42f834d39c0afb64818d7e027

4 files changed, 51 insertions, 18 deletions

diff --git a/nova/tests/test_imagebackend.py b/nova/tests/test_imagebackend.py
index 871e25dc8..d571bbf9e 100644
--- a/nova/tests/test_imagebackend.py
+++ b/nova/tests/test_imagebackend.py
@@ -156,6 +156,7 @@ class RawTestCase(_ImageTestCase, test.TestCase):
     def setUp(self):
         self.image_class = imagebackend.Raw
         super(RawTestCase, self).setUp()
+        self.stubs.Set(imagebackend.Raw, 'correct_format', lambda _: None)
 
     def prepare_mocks(self):
         fn = self.mox.CreateMockAnything()
@@ -198,6 +199,24 @@ class RawTestCase(_ImageTestCase, test.TestCase):
 
         self.mox.VerifyAll()
 
+    def test_correct_format(self):
+        info = self.mox.CreateMockAnything()
+        self.stubs.UnsetAll()
+
+        self.mox.StubOutWithMock(os.path, 'exists')
+        self.mox.StubOutWithMock(imagebackend.images, 'qemu_img_info')
+
+        os.path.exists(self.PATH).AndReturn(True)
+        info = self.mox.CreateMockAnything()
+        info.file_format = 'foo'
+        imagebackend.images.qemu_img_info(self.PATH).AndReturn(info)
+        self.mox.ReplayAll()
+
+        image = self.image_class(self.INSTANCE, self.NAME, path=self.PATH)
+        self.assertEqual(image.driver_format, 'foo')
+
+        self.mox.VerifyAll()
+
 
 class Qcow2TestCase(_ImageTestCase, test.TestCase):
     SIZE = 1024 * 1024 * 1024
diff --git a/nova/tests/test_libvirt.py b/nova/tests/test_libvirt.py
index 8c9d6e5f5..1413eb98c 100644
--- a/nova/tests/test_libvirt.py
+++ b/nova/tests/test_libvirt.py
@@ -2722,10 +2722,10 @@ class LibvirtConnTestCase(test.TestCase):
                                             instance,
                                             None,
                                             image_meta)
+        conn._create_image(context, instance,
+                           disk_info['mapping'])
         xml = conn.to_xml(instance, None,
                           disk_info, image_meta)
-        conn._create_image(context, instance, xml,
-                           disk_info['mapping'])
 
         wantFiles = [
             {'filename': '356a192b7913b04c54574d18c28d46e6395428ab',
@@ -2783,10 +2783,10 @@ class LibvirtConnTestCase(test.TestCase):
                                             instance,
                                             None,
                                             image_meta)
+        conn._create_image(context, instance,
+                           disk_info['mapping'])
         xml = conn.to_xml(instance, None,
                           disk_info, image_meta)
-        conn._create_image(context, instance, xml,
-                           disk_info['mapping'])
 
         wantFiles = [
             {'filename': '356a192b7913b04c54574d18c28d46e6395428ab',
@@ -4879,7 +4879,7 @@ class LibvirtDriverTestCase(test.TestCase):
         def fake_plug_vifs(instance, network_info):
             pass
 
-        def fake_create_image(context, inst, libvirt_xml,
+        def fake_create_image(context, inst,
                               disk_mapping, suffix='',
                               disk_images=None, network_info=None,
                               block_device_info=None):
diff --git a/nova/virt/libvirt/driver.py b/nova/virt/libvirt/driver.py
index 498ef1d82..7785d13e2 100755
--- a/nova/virt/libvirt/driver.py
+++ b/nova/virt/libvirt/driver.py
@@ -1356,6 +1356,12 @@ class LibvirtDriver(driver.ComputeDriver):
         disk_info = blockinfo.get_disk_info(CONF.libvirt_type,
                                             instance,
                                             block_device_info)
+        # NOTE(vish): This could generate the wrong device_format if we are
+        #             using the raw backend and the images don't exist yet.
+        #             The create_images_and_backing below doesn't properly
+        #             regenerate raw backend images, however, so when it
+        #             does we need to (re)generate the xml after the images
+        #             are in place.
         xml = self.to_xml(instance, network_info, disk_info,
                           block_device_info=block_device_info,
                           write_to_disk=True)
@@ -1461,13 +1467,14 @@ class LibvirtDriver(driver.ComputeDriver):
                                             None,
                                             image_meta,
                                             rescue=True)
-        xml = self.to_xml(instance, network_info, disk_info,
-                          image_meta, rescue=rescue_images)
-        self._create_image(context, instance, xml,
+        self._create_image(context, instance,
                            disk_info['mapping'],
                            '.rescue', rescue_images,
                            network_info=network_info,
                            admin_pass=rescue_password)
+        xml = self.to_xml(instance, network_info, disk_info,
+                          image_meta, rescue=rescue_images,
+                          write_to_disk=True)
         self._destroy(instance)
         self._create_domain(xml)
 
@@ -1505,16 +1512,16 @@ class LibvirtDriver(driver.ComputeDriver):
                                             instance,
                                             block_device_info,
                                             image_meta)
-        xml = self.to_xml(instance, network_info,
-                          disk_info, image_meta,
-                          block_device_info=block_device_info)
-
-        self._create_image(context, instance, xml,
+        self._create_image(context, instance,
                            disk_info['mapping'],
                            network_info=network_info,
                            block_device_info=block_device_info,
                            files=injected_files,
                            admin_pass=admin_password)
+        xml = self.to_xml(instance, network_info,
+                          disk_info, image_meta,
+                          block_device_info=block_device_info,
+                          write_to_disk=True)
 
         self._create_domain_and_network(xml, instance, network_info,
                                         block_device_info)
@@ -1720,7 +1727,7 @@ class LibvirtDriver(driver.ComputeDriver):
         if os.path.exists(console_log):
             libvirt_utils.chown(console_log, os.getuid())
 
-    def _create_image(self, context, instance, libvirt_xml,
+    def _create_image(self, context, instance,
                       disk_mapping, suffix='',
                       disk_images=None, network_info=None,
                       block_device_info=None, files=None, admin_pass=None):
@@ -1748,7 +1755,6 @@ class LibvirtDriver(driver.ComputeDriver):
         fileutils.ensure_tree(basepath(suffix=''))
 
         LOG.info(_('Creating image'), instance=instance)
-        libvirt_utils.write_to_file(basepath('libvirt.xml'), libvirt_xml)
 
         # NOTE(dprince): for rescue console.log may already exist... chown it.
         self._chown_console_log_for_instance(instance)
@@ -3524,14 +3530,15 @@ class LibvirtDriver(driver.ComputeDriver):
                                             instance,
                                             block_device_info,
                                             image_meta)
-        xml = self.to_xml(instance, network_info, disk_info,
-                          block_device_info=block_device_info)
         # assume _create_image do nothing if a target file exists.
         # TODO(oda): injecting files is not necessary
-        self._create_image(context, instance, xml,
+        self._create_image(context, instance,
                            disk_mapping=disk_info['mapping'],
                            network_info=network_info,
                            block_device_info=None)
+        xml = self.to_xml(instance, network_info, disk_info,
+                          block_device_info=block_device_info,
+                          write_to_disk=True)
         self._create_domain_and_network(xml, instance, network_info,
                                         block_device_info)
         timer = utils.FixedIntervalLoopingCall(self._wait_for_running,
diff --git a/nova/virt/libvirt/imagebackend.py b/nova/virt/libvirt/imagebackend.py
index c15896986..b6b1b88aa 100755
--- a/nova/virt/libvirt/imagebackend.py
+++ b/nova/virt/libvirt/imagebackend.py
@@ -195,6 +195,12 @@ class Raw(Image):
                                   disk_name))
         self.snapshot_name = snapshot_name
         self.preallocate = CONF.preallocate_images != 'none'
+        self.correct_format()
+
+    def correct_format(self):
+        if os.path.exists(self.path):
+            data = images.qemu_img_info(self.path)
+            self.driver_format = data.file_format or 'raw'
 
     def create_image(self, prepare_template, base, size, *args, **kwargs):
         @lockutils.synchronized(base, 'nova-', external=True,
@@ -213,6 +219,7 @@ class Raw(Image):
             if not os.path.exists(self.path):
                 with utils.remove_path_on_error(self.path):
                     copy_raw_image(base, self.path, size)
+        self.correct_format()
 
     def snapshot_create(self):
         pass