openstack/nova
Code Issues Proposed changes

Merge "libvirt: add discard support for attached volumes"

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This commit is contained in:
Jenkins 2016-01-13 10:40:33 +00:00 committed by Gerrit Code Review
commit dc905be8b6
5 changed files with 148 additions and 2 deletions
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37
nova/tests/unit/virt/libvirt/test_driver.py
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@ -5276,6 +5276,37 @@ class LibvirtConnTestCase(test.NoDBTestCase):
instance,
"/dev/sda")
def _test_check_discard(self, mock_log, driver_discard=None,
bus=None, should_log=False):
mock_config = mock.Mock()
mock_config.driver_discard = driver_discard
mock_config.target_bus = bus
mock_instance = mock.Mock()
drvr = libvirt_driver.LibvirtDriver(fake.FakeVirtAPI(), False)
drvr._check_discard_for_attach_volume(mock_config, mock_instance)
self.assertEqual(should_log, mock_log.called)
@mock.patch('nova.virt.libvirt.driver.LOG.debug')
def test_check_discard_for_attach_volume_no_unmap(self, mock_log):
self._test_check_discard(mock_log, driver_discard=None,
bus='scsi', should_log=False)
@mock.patch('nova.virt.libvirt.driver.LOG.debug')
def test_check_discard_for_attach_volume_blk_controller(self, mock_log):
self._test_check_discard(mock_log, driver_discard='unmap',
bus='virtio', should_log=True)
@mock.patch('nova.virt.libvirt.driver.LOG.debug')
def test_check_discard_for_attach_volume_valid_controller(self, mock_log):
self._test_check_discard(mock_log, driver_discard='unmap',
bus='scsi', should_log=False)
@mock.patch('nova.virt.libvirt.driver.LOG.debug')
def test_check_discard_for_attach_volume_blk_controller_no_unmap(self,
mock_log):
self._test_check_discard(mock_log, driver_discard=None,
bus='virtio', should_log=False)
@mock.patch('nova.utils.get_image_from_system_metadata')
@mock.patch('nova.virt.libvirt.blockinfo.get_info_from_bdm')
@mock.patch('nova.virt.libvirt.host.Host.get_domain')
@ -5305,9 +5336,10 @@ class LibvirtConnTestCase(test.NoDBTestCase):
mock.patch.object(drvr, '_connect_volume'),
mock.patch.object(drvr, '_get_volume_config',
return_value=mock_conf),
mock.patch.object(drvr, '_set_cache_mode')
mock.patch.object(drvr, '_set_cache_mode'),
mock.patch.object(drvr, '_check_discard_for_attach_volume')
) as (mock_connect_volume, mock_get_volume_config,
mock_set_cache_mode):
mock_set_cache_mode, mock_check_discard):
for state in (power_state.RUNNING, power_state.PAUSED):
mock_dom.info.return_value = [state, 512, 512, 2, 1234, 5678]
@ -5328,6 +5360,7 @@ class LibvirtConnTestCase(test.NoDBTestCase):
mock_set_cache_mode.assert_called_with(mock_conf)
mock_dom.attachDeviceFlags.assert_called_with(
mock_conf.to_xml(), flags=flags)
mock_check_discard.assert_called_with(mock_conf, instance)
@mock.patch('nova.virt.libvirt.host.Host.get_domain')
def test_detach_volume_with_vir_domain_affect_live_flag(self,

58
nova/tests/unit/virt/libvirt/volume/test_volume.py
View File

@ -13,6 +13,8 @@
# License for the specific language governing permissions and limitations
# under the License.
import mock
from nova import exception
from nova import test
from nova.tests.unit.virt.libvirt import fakelibvirt
@ -167,6 +169,7 @@ class LibvirtVolumeTestCase(LibvirtISCSIVolumeBaseTestCase):
self.assertEqual('block', tree.get('type'))
self.assertEqual('fake_serial', tree.find('./serial').text)
self.assertIsNone(tree.find('./blockio'))
self.assertIsNone(tree.find("driver[@discard]"))
def test_libvirt_volume_driver_blockio(self):
libvirt_driver = volume.LibvirtVolumeDriver(self.fake_conn)
@ -258,3 +261,58 @@ class LibvirtVolumeTestCase(LibvirtISCSIVolumeBaseTestCase):
tree = conf.format_dom()
readonly = tree.find('./readonly')
self.assertIsNotNone(readonly)
@mock.patch('nova.virt.libvirt.host.Host.has_min_version')
def test_libvirt_volume_driver_discard_true(self, mock_has_min_version):
# Check the discard attrib is present in driver section
mock_has_min_version.return_value = True
libvirt_driver = volume.LibvirtVolumeDriver(self.fake_conn)
connection_info = {
'driver_volume_type': 'fake',
'data': {
'device_path': '/foo',
'discard': True,
},
'serial': 'fake_serial',
}
conf = libvirt_driver.get_config(connection_info, self.disk_info)
tree = conf.format_dom()
driver_node = tree.find("driver[@discard]")
self.assertIsNotNone(driver_node)
self.assertEqual('unmap', driver_node.attrib['discard'])
def test_libvirt_volume_driver_discard_false(self):
# Check the discard attrib is not present in driver section
libvirt_driver = volume.LibvirtVolumeDriver(self.fake_conn)
connection_info = {
'driver_volume_type': 'fake',
'data': {
'device_path': '/foo',
'discard': False,
},
'serial': 'fake_serial',
}
conf = libvirt_driver.get_config(connection_info, self.disk_info)
tree = conf.format_dom()
self.assertIsNone(tree.find("driver[@discard]"))
@mock.patch('nova.virt.libvirt.host.Host.has_min_version')
def test_libvirt_volume_driver_discard_true_bad_version(
self, mock_has_min_version):
# Check the discard attrib is not present in driver section
mock_has_min_version.return_value = False
libvirt_driver = volume.LibvirtVolumeDriver(self.fake_conn)
connection_info = {
'driver_volume_type': 'fake',
'data': {
'device_path': '/foo',
'discard': True,
},
'serial': 'fake_serial',
}
conf = libvirt_driver.get_config(connection_info, self.disk_info)
tree = conf.format_dom()
self.assertIsNone(tree.find("driver[@discard]"))

19
nova/virt/libvirt/driver.py
View File

@ -1103,6 +1103,23 @@ class LibvirtDriver(driver.ComputeDriver):
**encryption)
return encryptor
def _check_discard_for_attach_volume(self, conf, instance):
"""Perform some checks for volumes configured for discard support.
If discard is configured for the volume, and the guest is using a
configuration known to not work, we will log a message explaining
the reason why.
"""
if conf.driver_discard == 'unmap' and conf.target_bus == 'virtio':
LOG.debug('Attempting to attach volume %(id)s with discard '
'support enabled to an instance using an '
'unsupported configuration. target_bus = '
'%(bus)s. Trim commands will not be issued to '
'the storage device.',
{'bus': conf.target_bus,
'id': conf.serial},
instance=instance)
def attach_volume(self, context, connection_info, instance, mountpoint,
disk_bus=None, device_type=None, encryption=None):
image_meta = objects.ImageMeta.from_instance(instance)
@ -1136,6 +1153,8 @@ class LibvirtDriver(driver.ComputeDriver):
conf = self._get_volume_config(connection_info, disk_info)
self._set_cache_mode(conf)
self._check_discard_for_attach_volume(conf, instance)
try:
state = guest.get_power_state(self._host)
live = state in (power_state.RUNNING, power_state.PAUSED)

27
nova/virt/libvirt/volume/volume.py
View File

@ -24,6 +24,8 @@ from nova import exception
from nova.i18n import _LE
from nova.i18n import _LW
from nova.virt.libvirt import config as vconfig
import nova.virt.libvirt.driver
from nova.virt.libvirt import host
from nova.virt.libvirt import utils as libvirt_utils
LOG = logging.getLogger(__name__)
@ -38,6 +40,8 @@ volume_opts = [
CONF = cfg.CONF
CONF.register_opts(volume_opts, 'libvirt')
SHOULD_LOG_DISCARD_WARNING = True
class LibvirtBaseVolumeDriver(object):
"""Base class for volume drivers."""
@ -96,6 +100,29 @@ class LibvirtBaseVolumeDriver(object):
raise exception.InvalidVolumeAccessMode(
access_mode=access_mode)
# Configure usage of discard
if data.get('discard', False) is True:
min_qemu = nova.virt.libvirt.driver.MIN_QEMU_DISCARD_VERSION
min_libvirt = nova.virt.libvirt.driver.MIN_LIBVIRT_DISCARD_VERSION
if self.connection._host.has_min_version(min_libvirt,
min_qemu,
host.HV_DRIVER_QEMU):
conf.driver_discard = 'unmap'
else:
global SHOULD_LOG_DISCARD_WARNING
if SHOULD_LOG_DISCARD_WARNING:
SHOULD_LOG_DISCARD_WARNING = False
LOG.warning(_LW('Unable to attach %(type)s volume '
'%(serial)s with discard enabled: qemu '
'%(qemu)s and libvirt %(libvirt)s or '
'later are required.'),
{
'qemu': min_qemu,
'libvirt': min_libvirt,
'serial': conf.serial,
'type': connection_info['driver_volume_type']
})
return conf
def connect_volume(self, connection_info, disk_info):

9
releasenotes/notes/cinder-backend-report-discard-1def1c28140def9b.yaml Normal file
View File

@ -0,0 +1,9 @@
---
features:
- Add support for enabling discard support for block devices with libvirt.
This will be enabled for Cinder volume attachments that specify support
for the feature in their connection properties. This requires support to
be present in the version of libvirt (v1.0.6+) and qemu (v1.6.0+) used
along with the configured virtual drivers for the instance. The
virtio-blk driver does not support this functionality.