fup: Remove unused legacy block_device_info format

As announced on the ML [1] this change removes the now unused legacy format
from the codebase and updates the reference docs.

[1] http://lists.openstack.org/pipermail/openstack-discuss/2021-August/024116.html

Change-Id: I3895b61b436b9bb882477d2d1b3f4907f03b3b1c

15 files changed, 28 insertions, 234 deletions

diff --git a/doc/source/reference/block-device-structs.rst b/doc/source/reference/block-device-structs.rst
index 7778161214..1b8636c537 100644
--- a/doc/source/reference/block-device-structs.rst
+++ b/doc/source/reference/block-device-structs.rst
@@ -59,6 +59,10 @@ or volumes, and some associated data.
 ``block_device_info``
 ---------------------
 
+.. versionchanged:: 24.0.0 (Xena)
+
+   The legacy block_device_info format is no longer supported.
+
 Drivers do not directly use BDM objects. Instead, they are transformed into a
 different driver-specific representation. This representation is normally
 called ``block_device_info``, and is generated by
@@ -74,24 +78,23 @@ called ``block_device_info``, and is generated by
 ``swap``
     A swap disk, or None if there is no swap disk
 
-The disks are represented in one of two ways, depending on the specific
-driver currently in use. There's the 'new' representation, used by the libvirt
-and vmwareAPI drivers, and the 'legacy' representation used by all other
-drivers. The legacy representation is a plain dict. It does not contain the
-same information as the new representation.
+.. note::
+
+    The disks were previously represented in one of two ways, depending on the
+    specific driver in use. A legacy plain dict format or the currently used
+    DriverBlockDevice format discussed below. Support for the legacy format
+    was removed in Xena.
 
-The new representation involves subclasses of
-``nova.block_device.DriverBlockDevice``. As well as containing different
-fields, the new representation significantly also retains a reference to the
-underlying BDM object. This means that by manipulating the
-``DriverBlockDevice`` object, the driver is able to persist data to the BDM
-object in the DB.
+Disks are represented by subclasses of ``nova.block_device.DriverBlockDevice``.
+These subclasses retain a reference to the underlying BDM object. This means
+that by manipulating the ``DriverBlockDevice`` object, the driver is able to
+persist data to the BDM object in the DB.
 
 .. note::
 
     Common usage is to pull ``block_device_mapping`` out of this
     dict into a variable called ``block_device_mapping``. This is not a
-    ``BlockDeviceMapping`` object, or list of them.
+    ``BlockDeviceMapping`` object, or a list of them.
 
 .. note::
 
diff --git a/nova/block_device.py b/nova/block_device.py
index 340d4b9285..a026078317 100644
--- a/nova/block_device.py
+++ b/nova/block_device.py
@@ -311,30 +311,6 @@ def snapshot_from_bdm(snapshot_id, template):
     return BlockDeviceDict(snapshot_dict)
 
 
-def legacy_mapping(block_device_mapping):
-    """Transform a list of block devices of an instance back to the
-    legacy data format.
-    """
-
-    legacy_block_device_mapping = []
-
-    for bdm in block_device_mapping:
-        try:
-            legacy_block_device = BlockDeviceDict(bdm).legacy()
-        except exception.InvalidBDMForLegacy:
-            continue
-
-        legacy_block_device_mapping.append(legacy_block_device)
-
-    # Re-enumerate the ephemeral devices
-    for i, dev in enumerate(dev for dev in legacy_block_device_mapping
-                            if dev['virtual_name'] and
-                            is_ephemeral(dev['virtual_name'])):
-        dev['virtual_name'] = dev['virtual_name'][:-1] + str(i)
-
-    return legacy_block_device_mapping
-
-
 def from_legacy_mapping(legacy_block_device_mapping, image_uuid='',
                         root_device_name=None, no_root=False):
     """Transform a legacy list of block devices to the new data format."""
diff --git a/nova/compute/manager.py b/nova/compute/manager.py
index 6c5d6274a0..4bea89bc82 100644
--- a/nova/compute/manager.py
+++ b/nova/compute/manager.py
@@ -578,8 +578,6 @@ class ComputeManager(manager.Manager):
         # compute manager via the virtapi, so we want it to be fully
         # initialized before that happens.
         self.driver = driver.load_compute_driver(self.virtapi, compute_driver)
-        self.use_legacy_block_device_info = \
-                            self.driver.need_legacy_block_device_info
         self.rt = resource_tracker.ResourceTracker(
             self.host, self.driver, reportclient=self.reportclient)
 
@@ -1939,23 +1937,6 @@ class ComputeManager(manager.Manager):
                                                 swap,
                                                 block_device_mapping)
 
-    def _block_device_info_to_legacy(self, block_device_info):
-        """Convert BDI to the old format for drivers that need it."""
-
-        if self.use_legacy_block_device_info:
-            ephemerals = driver_block_device.legacy_block_devices(
-                driver.block_device_info_get_ephemerals(block_device_info))
-            mapping = driver_block_device.legacy_block_devices(
-                driver.block_device_info_get_mapping(block_device_info))
-            swap = block_device_info['swap']
-            if swap:
-                swap = swap.legacy()
-
-            block_device_info.update({
-                'ephemerals': ephemerals,
-                'swap': swap,
-                'block_device_mapping': mapping})
-
     def _add_missing_dev_names(self, bdms, instance):
         for bdm in bdms:
             if bdm.device_name is not None:
@@ -1977,7 +1958,6 @@ class ComputeManager(manager.Manager):
                 mapping, context, instance, self.volume_api, self.driver,
                 wait_func=self._await_block_device_map_created)
 
-            self._block_device_info_to_legacy(block_device_info)
             return block_device_info
 
         except exception.OverQuota as e:
@@ -2093,8 +2073,6 @@ class ComputeManager(manager.Manager):
                 driver.block_device_info_get_mapping(block_device_info),
                 context, instance, self.volume_api, self.driver)
 
-        self._block_device_info_to_legacy(block_device_info)
-
         return block_device_info
 
     def _build_failed(self, node):
diff --git a/nova/tests/unit/compute/test_compute.py b/nova/tests/unit/compute/test_compute.py
index 943712085d..cbb699ec4a 100644
--- a/nova/tests/unit/compute/test_compute.py
+++ b/nova/tests/unit/compute/test_compute.py
@@ -1424,7 +1424,6 @@ class ComputeVolumeTestCase(BaseTestCase):
         }
 
         manager = compute_manager.ComputeManager()
-        manager.use_legacy_block_device_info = False
         mock_bdm_saves = [mock.patch.object(bdm, 'save') for bdm in bdms]
         with test.nested(*mock_bdm_saves):
             block_device_info = manager._prep_block_device(self.context,
diff --git a/nova/tests/unit/test_block_device.py b/nova/tests/unit/test_block_device.py
index 2e9d768d58..f5a4fc5694 100644
--- a/nova/tests/unit/test_block_device.py
+++ b/nova/tests/unit/test_block_device.py
@@ -656,45 +656,6 @@ class TestBlockDeviceDict(test.NoDBTestCase):
         self.assertIn('Specifying volume type to existing volume is '
                       'not supported', str(ex))
 
-    def test_legacy(self):
-        for legacy, new in zip(self.legacy_mapping, self.new_mapping):
-            self.assertThat(
-                legacy,
-                matchers.IsSubDictOf(new.legacy()))
-
-    def test_legacy_mapping(self):
-        got_legacy = block_device.legacy_mapping(self.new_mapping)
-
-        for legacy, expected in zip(got_legacy, self.legacy_mapping):
-            self.assertThat(expected, matchers.IsSubDictOf(legacy))
-
-    def test_legacy_source_image(self):
-        for legacy, new in zip(self.legacy_mapping_source_image,
-                               self.new_mapping_source_image):
-            if new['destination_type'] == 'volume':
-                self.assertThat(legacy, matchers.IsSubDictOf(new.legacy()))
-            else:
-                self.assertRaises(exception.InvalidBDMForLegacy, new.legacy)
-
-    def test_legacy_mapping_source_image(self):
-        got_legacy = block_device.legacy_mapping(self.new_mapping)
-
-        for legacy, expected in zip(got_legacy, self.legacy_mapping):
-            self.assertThat(expected, matchers.IsSubDictOf(legacy))
-
-    def test_legacy_mapping_from_object_list(self):
-        bdm1 = objects.BlockDeviceMapping()
-        bdm1 = objects.BlockDeviceMapping._from_db_object(
-            None, bdm1, fake_block_device.FakeDbBlockDeviceDict(
-                self.new_mapping[0]))
-        bdm2 = objects.BlockDeviceMapping()
-        bdm2 = objects.BlockDeviceMapping._from_db_object(
-            None, bdm2, fake_block_device.FakeDbBlockDeviceDict(
-                self.new_mapping[1]))
-        bdmlist = objects.BlockDeviceMappingList()
-        bdmlist.objects = [bdm1, bdm2]
-        block_device.legacy_mapping(bdmlist)
-
     def test_image_mapping(self):
         removed_fields = ['id', 'instance_uuid', 'connection_info',
                           'created_at', 'updated_at', 'deleted_at', 'deleted']
diff --git a/nova/tests/unit/virt/libvirt/test_driver.py b/nova/tests/unit/virt/libvirt/test_driver.py
index 03eea0555f..a30c5d55c0 100644
--- a/nova/tests/unit/virt/libvirt/test_driver.py
+++ b/nova/tests/unit/virt/libvirt/test_driver.py
@@ -938,10 +938,6 @@ class LibvirtConnTestCase(test.NoDBTestCase,
         inst = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
         self.assertPublicAPISignatures(baseinst, inst)
 
-    def test_legacy_block_device_info(self):
-        drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), True)
-        self.assertFalse(drvr.need_legacy_block_device_info)
-
     @mock.patch.object(libvirt_driver.LibvirtDriver, '_get_cpu_traits')
     @mock.patch.object(libvirt_driver.LibvirtDriver, '_get_storage_bus_traits')
     @mock.patch.object(libvirt_driver.LibvirtDriver, '_get_video_model_traits')
diff --git a/nova/tests/unit/virt/test_block_device.py b/nova/tests/unit/virt/test_block_device.py
index bed9052fa1..9fc97c0ff8 100644
--- a/nova/tests/unit/virt/test_block_device.py
+++ b/nova/tests/unit/virt/test_block_device.py
@@ -64,10 +64,6 @@ class TestDriverBlockDevice(test.NoDBTestCase):
         'swap_size': 2,
         'disk_bus': 'scsi'}
 
-    swap_legacy_driver_bdm = {
-        'device_name': '/dev/sdb1',
-        'swap_size': 2}
-
     ephemeral_bdm_dict = block_device.BlockDeviceDict(
         {'id': 2, 'instance_uuid': uuids.instance,
          'device_name': '/dev/sdc1',
@@ -87,12 +83,6 @@ class TestDriverBlockDevice(test.NoDBTestCase):
         'guest_format': 'ext4',
         'disk_bus': 'scsi'}
 
-    ephemeral_legacy_driver_bdm = {
-        'device_name': '/dev/sdc1',
-        'size': 4,
-        'virtual_name': 'ephemeral0',
-        'num': 0}
-
     volume_bdm_dict = block_device.BlockDeviceDict(
         {'id': 3, 'instance_uuid': uuids.instance,
          'device_name': '/dev/sda1',
@@ -117,11 +107,6 @@ class TestDriverBlockDevice(test.NoDBTestCase):
         'boot_index': 0,
         'volume_type': None}
 
-    volume_legacy_driver_bdm = {
-        'mount_device': '/dev/sda1',
-        'connection_info': {"fake": "connection_info"},
-        'delete_on_termination': False}
-
     volume_bdm_dict_without_conn_info = block_device.BlockDeviceDict(
         {'id': 3, 'instance_uuid': uuids.instance,
          'device_name': '/dev/sda1',
@@ -172,11 +157,6 @@ class TestDriverBlockDevice(test.NoDBTestCase):
         'boot_index': -1,
         'volume_type': None}
 
-    volsnapshot_legacy_driver_bdm = {
-        'mount_device': '/dev/sda2',
-        'connection_info': {"fake": "connection_info"},
-        'delete_on_termination': True}
-
     volimage_bdm_dict = block_device.BlockDeviceDict(
         {'id': 5, 'instance_uuid': uuids.instance,
          'device_name': '/dev/sda2',
@@ -202,11 +182,6 @@ class TestDriverBlockDevice(test.NoDBTestCase):
         'boot_index': -1,
         'volume_type': None}
 
-    volimage_legacy_driver_bdm = {
-        'mount_device': '/dev/sda2',
-        'connection_info': {"fake": "connection_info"},
-        'delete_on_termination': True}
-
     volblank_bdm_dict = block_device.BlockDeviceDict(
         {'id': 6, 'instance_uuid': uuids.instance,
          'device_name': '/dev/sda2',
@@ -231,11 +206,6 @@ class TestDriverBlockDevice(test.NoDBTestCase):
         'boot_index': -1,
         'volume_type': None}
 
-    volblank_legacy_driver_bdm = {
-        'mount_device': '/dev/sda2',
-        'connection_info': {"fake": "connection_info"},
-        'delete_on_termination': True}
-
     def setUp(self):
         super(TestDriverBlockDevice, self).setUp()
         self.volume_api = mock.MagicMock(autospec=cinder.API)
@@ -339,9 +309,6 @@ class TestDriverBlockDevice(test.NoDBTestCase):
             # Reset the value
             test_bdm[field] = value
 
-        expected = getattr(self, "%s_legacy_driver_bdm" % name)
-        self.assertThat(expected, matchers.DictMatches(test_bdm.legacy()))
-
         # Test passthru attributes
         for passthru in test_bdm._proxy_as_attr:
             self.assertEqual(getattr(test_bdm, passthru),
@@ -1289,37 +1256,11 @@ class TestDriverBlockDevice(test.NoDBTestCase):
                          driver_block_device.convert_volume(
                              self.volume_bdm_without_conn_info))
 
-    def test_legacy_block_devices(self):
-        test_snapshot = self.driver_classes['volsnapshot'](
-            self.volsnapshot_bdm)
-
-        block_device_mapping = [test_snapshot, test_snapshot]
-        legacy_bdm = driver_block_device.legacy_block_devices(
-            block_device_mapping)
-        self.assertEqual(legacy_bdm, [self.volsnapshot_legacy_driver_bdm,
-                                       self.volsnapshot_legacy_driver_bdm])
-
-        # Test that the ephemerals work as expected
-        test_ephemerals = [self.driver_classes['ephemeral'](
-            self.ephemeral_bdm) for _ in range(2)]
-        expected = [self.ephemeral_legacy_driver_bdm.copy()
-                             for _ in range(2)]
-        expected[0]['virtual_name'] = 'ephemeral0'
-        expected[0]['num'] = 0
-        expected[1]['virtual_name'] = 'ephemeral1'
-        expected[1]['num'] = 1
-        legacy_ephemerals = driver_block_device.legacy_block_devices(
-            test_ephemerals)
-        self.assertEqual(expected, legacy_ephemerals)
-
     def test_get_swap(self):
         swap = [self.swap_driver_bdm]
-        legacy_swap = [self.swap_legacy_driver_bdm]
         no_swap = [self.volume_driver_bdm]
 
         self.assertEqual(swap[0], driver_block_device.get_swap(swap))
-        self.assertEqual(legacy_swap[0],
-                          driver_block_device.get_swap(legacy_swap))
         self.assertIsNone(driver_block_device.get_swap(no_swap))
         self.assertIsNone(driver_block_device.get_swap([]))
 
diff --git a/nova/tests/unit/virt/vmwareapi/test_driver_api.py b/nova/tests/unit/virt/vmwareapi/test_driver_api.py
index 4086a7d7cc..8d3589c7bb 100644
--- a/nova/tests/unit/virt/vmwareapi/test_driver_api.py
+++ b/nova/tests/unit/virt/vmwareapi/test_driver_api.py
@@ -266,9 +266,6 @@ class VMwareAPIVMTestCase(test.NoDBTestCase,
         super(VMwareAPIVMTestCase, self).tearDown()
         vmwareapi_fake.cleanup()
 
-    def test_legacy_block_device_info(self):
-        self.assertFalse(self.conn.need_legacy_block_device_info)
-
     def test_get_host_ip_addr(self):
         self.assertEqual(HOST, self.conn.get_host_ip_addr())
 
diff --git a/nova/virt/block_device.py b/nova/virt/block_device.py
index 7dcc5ff161..8adffdaf9a 100644
--- a/nova/virt/block_device.py
+++ b/nova/virt/block_device.py
@@ -83,9 +83,8 @@ class DriverBlockDevice(dict):
 
     Uses block device objects internally to do the database access.
 
-    _fields and _legacy_fields class attributes present a set of fields that
-    are expected on a certain DriverBlockDevice type. We may have more legacy
-    versions in the future.
+    The _fields class attribute present a set of fields that
+    are expected on a certain DriverBlockDevice type.
 
     If an attribute access is attempted for a name that is found in the
     _proxy_as_attr set, it will be proxied to the underlying object. This
@@ -103,7 +102,6 @@ class DriverBlockDevice(dict):
     """
 
     _fields = set()
-    _legacy_fields = set()
 
     _proxy_as_attr_inherited = set(['uuid', 'is_volume'])
     _update_on_save = {'disk_bus': None,
@@ -179,14 +177,6 @@ class DriverBlockDevice(dict):
         else:
             return super(DriverBlockDevice, self).get(name, default)
 
-    def legacy(self):
-        """Basic legacy transformation.
-
-        Basic method will just drop the fields that are not in
-        _legacy_fields set. Override this in subclass if needed.
-        """
-        return {key: self.get(key) for key in self._legacy_fields}
-
     def attach(self, **kwargs):
         """Make the device available to be used by VMs.
 
@@ -223,7 +213,6 @@ class DriverBlockDevice(dict):
 
 class DriverSwapBlockDevice(DriverBlockDevice):
     _fields = set(['device_name', 'swap_size', 'disk_bus'])
-    _legacy_fields = _fields - set(['disk_bus'])
 
     _update_on_save = {'disk_bus': None,
                        'device_name': None}
@@ -241,8 +230,6 @@ class DriverSwapBlockDevice(DriverBlockDevice):
 class DriverEphemeralBlockDevice(DriverBlockDevice):
     _new_only_fields = set(['disk_bus', 'device_type', 'guest_format'])
     _fields = set(['device_name', 'size']) | _new_only_fields
-    _legacy_fields = (_fields - _new_only_fields |
-                      set(['num', 'virtual_name']))
 
     def _transform(self):
         if not block_device.new_format_is_ephemeral(self._bdm_obj):
@@ -255,20 +242,19 @@ class DriverEphemeralBlockDevice(DriverBlockDevice):
             'guest_format': self._bdm_obj.guest_format
         })
 
-    def legacy(self, num=0):
-        legacy_bdm = super(DriverEphemeralBlockDevice, self).legacy()
-        legacy_bdm['num'] = num
-        legacy_bdm['virtual_name'] = 'ephemeral' + str(num)
-        return legacy_bdm
-
 
 class DriverVolumeBlockDevice(DriverBlockDevice):
-    _legacy_fields = set(['connection_info', 'mount_device',
-                          'delete_on_termination'])
-    _new_fields = set(['guest_format', 'device_type',
-                       'disk_bus', 'boot_index',
-                       'attachment_id'])
-    _fields = _legacy_fields | _new_fields
+    _new_fields = set([
+        'guest_format',
+        'device_type',
+        'disk_bus',
+        'boot_index',
+        'attachment_id'])
+    _fields = set([
+        'connection_info',
+        'mount_device',
+        'delete_on_termination'
+    ]) | _new_fields
 
     _valid_source = 'volume'
     _valid_destination = 'volume'
@@ -884,19 +870,6 @@ def refresh_conn_infos(block_device_mapping, *refresh_args, **refresh_kwargs):
     return block_device_mapping
 
 
-def legacy_block_devices(block_device_mapping):
-    bdms = [bdm.legacy() for bdm in block_device_mapping]
-
-    # Re-enumerate ephemeral devices
-    if all(isinstance(bdm, DriverEphemeralBlockDevice)
-           for bdm in block_device_mapping):
-        for i, dev in enumerate(bdms):
-            dev['virtual_name'] = dev['virtual_name'][:-1] + str(i)
-            dev['num'] = i
-
-    return bdms
-
-
 def get_swap(transformed_list):
     """Get the swap device out of the list context.
 
diff --git a/nova/virt/driver.py b/nova/virt/driver.py
index df3b1e5dda..f5f622d72d 100644
--- a/nova/virt/driver.py
+++ b/nova/virt/driver.py
@@ -1617,16 +1617,6 @@ class ComputeDriver(object):
         """
         return True
 
-    # TODO(lyarwood): This is no longer used and should be removed.
-    @property
-    def need_legacy_block_device_info(self):
-        """Tell the caller if the driver requires legacy block device info.
-
-        Tell the caller whether we expect the legacy format of block
-        device info to be passed in to methods that expect it.
-        """
-        return True
-
     def volume_snapshot_create(self, context, instance, volume_id,
                                create_info):
         """Snapshots volumes attached to a specified instance.
diff --git a/nova/virt/fake.py b/nova/virt/fake.py
index d94e339cd8..008aa94486 100644
--- a/nova/virt/fake.py
+++ b/nova/virt/fake.py
@@ -654,10 +654,6 @@ class FakeDriver(driver.ComputeDriver):
     def unquiesce(self, context, instance, image_meta):
         pass
 
-    @property
-    def need_legacy_block_device_info(self):
-        return False
-
 
 class FakeVirtAPI(virtapi.VirtAPI):
     @contextlib.contextmanager
diff --git a/nova/virt/hyperv/driver.py b/nova/virt/hyperv/driver.py
index 16cb9db8e9..350e59e295 100644
--- a/nova/virt/hyperv/driver.py
+++ b/nova/virt/hyperv/driver.py
@@ -144,10 +144,6 @@ class HyperVDriver(driver.ComputeDriver):
                         'has been deprecated In Queens, and will be removed '
                         'in Rocky.')
 
-    @property
-    def need_legacy_block_device_info(self):
-        return False
-
     def init_host(self, host):
         self._serialconsoleops.start_console_handlers()
         event_handler = eventhandler.InstanceEventHandler(
diff --git a/nova/virt/ironic/driver.py b/nova/virt/ironic/driver.py
index aabc05776e..5c34e5f2c5 100644
--- a/nova/virt/ironic/driver.py
+++ b/nova/virt/ironic/driver.py
@@ -1893,10 +1893,6 @@ class IronicDriver(virt_driver.ComputeDriver):
                         instance=instance)
             raise exception.ConsoleTypeUnavailable(console_type='serial')
 
-    @property
-    def need_legacy_block_device_info(self):
-        return False
-
     def prepare_networks_before_block_device_mapping(self, instance,
                                                      network_info):
         """Prepare networks before the block devices are mapped to instance.
diff --git a/nova/virt/libvirt/driver.py b/nova/virt/libvirt/driver.py
index cb7db5901f..de410b4e42 100644
--- a/nova/virt/libvirt/driver.py
+++ b/nova/virt/libvirt/driver.py
@@ -11537,10 +11537,6 @@ class LibvirtDriver(driver.ComputeDriver):
         LOG.info('Deletion of %s complete', target_del, instance=instance)
         return True
 
-    @property
-    def need_legacy_block_device_info(self):
-        return False
-
     def default_root_device_name(self, instance, image_meta, root_bdm):
         disk_bus = blockinfo.get_disk_bus_for_device_type(
             instance, CONF.libvirt.virt_type, image_meta, "disk")
diff --git a/nova/virt/vmwareapi/driver.py b/nova/virt/vmwareapi/driver.py
index 520d710cba..4eeae8a350 100644
--- a/nova/virt/vmwareapi/driver.py
+++ b/nova/virt/vmwareapi/driver.py
@@ -172,10 +172,6 @@ class VMwareVCDriver(driver.ComputeDriver):
                         '%(version)s in the 16.0.0 release.',
                         {'version': constants.NEXT_MIN_VC_VERSION})
 
-    @property
-    def need_legacy_block_device_info(self):
-        return False
-
     def _update_pbm_location(self):
         if CONF.vmware.pbm_wsdl_location:
             pbm_wsdl_loc = CONF.vmware.pbm_wsdl_location