text: #    Copyright 2013 OpenStack Foundation
  #
  #    Licensed under the Apache License, Version 2.0 (the "License"); you may
  #    not use this file except in compliance with the License. You may obtain
  #    a copy of the License at
  #
  #         http://www.apache.org/licenses/LICENSE-2.0
  #
  #    Unless required by applicable law or agreed to in writing, software
  #    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  #    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  #    License for the specific language governing permissions and limitations
  #    under the License.
  """RADOS Block Device Driver"""
  
  from __future__ import absolute_import
  import io
  import json
  import math
  import os
  import tempfile
  
  from eventlet import tpool
  from oslo_config import cfg
  from oslo_log import log as logging
  from oslo_utils import fileutils
  from oslo_utils import units
  import six
  from six.moves import urllib
  
  from cinder import exception
  from cinder.i18n import _, _LE, _LI, _LW
  from cinder.image import image_utils
  from cinder import interface
  from cinder import utils
  from cinder.volume import driver
  
  try:
      import rados
      import rbd
  except ImportError:
      rados = None
      rbd = None
  
  
  LOG = logging.getLogger(__name__)
  
  RBD_OPTS = [
      cfg.StrOpt('rbd_cluster_name',
                 default='ceph',
                 help='The name of ceph cluster'),
      cfg.StrOpt('rbd_pool',
                 default='rbd',
                 help='The RADOS pool where rbd volumes are stored'),
      cfg.StrOpt('rbd_user',
                 help='The RADOS client name for accessing rbd volumes '
                      '- only set when using cephx authentication'),
      cfg.StrOpt('rbd_ceph_conf',
                 default='',  # default determined by librados
                 help='Path to the ceph configuration file'),
      cfg.BoolOpt('rbd_flatten_volume_from_snapshot',
                  default=False,
                  help='Flatten volumes created from snapshots to remove '
                       'dependency from volume to snapshot'),
      cfg.StrOpt('rbd_secret_uuid',
                 help='The libvirt uuid of the secret for the rbd_user '
                      'volumes'),
      cfg.StrOpt('volume_tmp_dir',
                 help='Directory where temporary image files are stored '
                      'when the volume driver does not write them directly '
                      'to the volume.  Warning: this option is now deprecated, '
                      'please use image_conversion_dir instead.'),
      cfg.IntOpt('rbd_max_clone_depth',
                 default=5,
                 help='Maximum number of nested volume clones that are '
                      'taken before a flatten occurs. Set to 0 to disable '
                      'cloning.'),
      cfg.IntOpt('rbd_store_chunk_size', default=4,
                 help='Volumes will be chunked into objects of this size '
                      '(in megabytes).'),
      cfg.IntOpt('rados_connect_timeout', default=-1,
                 help='Timeout value (in seconds) used when connecting to '
                      'ceph cluster. If value < 0, no timeout is set and '
                      'default librados value is used.'),
      cfg.IntOpt('rados_connection_retries', default=3,
                 help='Number of retries if connection to ceph cluster '
                      'failed.'),
      cfg.IntOpt('rados_connection_interval', default=5,
                 help='Interval value (in seconds) between connection '
                      'retries to ceph cluster.')
  ]
  
  CONF = cfg.CONF
  CONF.register_opts(RBD_OPTS)
  
  
  class RBDImageMetadata(object):
      """RBD image metadata to be used with RBDImageIOWrapper."""
      def __init__(self, image, pool, user, conf):
          self.image = image
          self.pool = utils.convert_str(pool)
          self.user = utils.convert_str(user)
          self.conf = utils.convert_str(conf)
  
  
  class RBDImageIOWrapper(io.RawIOBase):
      """Enables LibRBD.Image objects to be treated as Python IO objects.
  
      Calling unimplemented interfaces will raise IOError.
      """
  
      def __init__(self, rbd_meta):
          super(RBDImageIOWrapper, self).__init__()
          self._rbd_meta = rbd_meta
          self._offset = 0
  
      def _inc_offset(self, length):
          self._offset += length
  
      @property
      def rbd_image(self):
          return self._rbd_meta.image
  
      @property
      def rbd_user(self):
          return self._rbd_meta.user
  
      @property
      def rbd_pool(self):
          return self._rbd_meta.pool
  
      @property
      def rbd_conf(self):
          return self._rbd_meta.conf
  
      def read(self, length=None):
          offset = self._offset
          total = self._rbd_meta.image.size()
  
          # NOTE(dosaboy): posix files do not barf if you read beyond their
          # length (they just return nothing) but rbd images do so we need to
          # return empty string if we have reached the end of the image.
          if (offset >= total):
              return b''
  
          if length is None:
              length = total
  
          if (offset + length) > total:
              length = total - offset
  
          self._inc_offset(length)
          return self._rbd_meta.image.read(int(offset), int(length))
  
      def write(self, data):
          self._rbd_meta.image.write(data, self._offset)
          self._inc_offset(len(data))
  
      def seekable(self):
          return True
  
      def seek(self, offset, whence=0):
          if whence == 0:
              new_offset = offset
          elif whence == 1:
              new_offset = self._offset + offset
          elif whence == 2:
              new_offset = self._rbd_meta.image.size()
              new_offset += offset
          else:
              raise IOError(_("Invalid argument - whence=%s not supported") %
                            (whence))
  
          if (new_offset < 0):
              raise IOError(_("Invalid argument"))
  
          self._offset = new_offset
  
      def tell(self):
          return self._offset
  
      def flush(self):
          try:
              self._rbd_meta.image.flush()
          except AttributeError:
              LOG.warning(_LW("flush() not supported in "
                              "this version of librbd"))
  
      def fileno(self):
          """RBD does not have support for fileno() so we raise IOError.
  
          Raising IOError is recommended way to notify caller that interface is
          not supported - see http://docs.python.org/2/library/io.html#io.IOBase
          """
          raise IOError(_("fileno() not supported by RBD()"))
  
      # NOTE(dosaboy): if IO object is not closed explicitly, Python auto closes
      # it which, if this is not overridden, calls flush() prior to close which
      # in this case is unwanted since the rbd image may have been closed prior
      # to the autoclean - currently triggering a segfault in librbd.
      def close(self):
          pass
  
  
  class RBDVolumeProxy(object):
      """Context manager for dealing with an existing rbd volume.
  
      This handles connecting to rados and opening an ioctx automatically, and
      otherwise acts like a librbd Image object.
  
      The underlying librados client and ioctx can be accessed as the attributes
      'client' and 'ioctx'.
      """
      def __init__(self, driver, name, pool=None, snapshot=None,
                   read_only=False):
          client, ioctx = driver._connect_to_rados(pool)
          if snapshot is not None:
              snapshot = utils.convert_str(snapshot)
  
          try:
              self.volume = driver.rbd.Image(ioctx,
                                             utils.convert_str(name),
                                             snapshot=snapshot,
                                             read_only=read_only)
          except driver.rbd.Error:
              LOG.exception(_LE("error opening rbd image %s"), name)
              driver._disconnect_from_rados(client, ioctx)
              raise
          self.driver = driver
          self.client = client
          self.ioctx = ioctx
  
      def __enter__(self):
          return self
  
      def __exit__(self, type_, value, traceback):
          try:
              self.volume.close()
          finally:
              self.driver._disconnect_from_rados(self.client, self.ioctx)
  
      def __getattr__(self, attrib):
          return getattr(self.volume, attrib)
  
  
  class RADOSClient(object):
      """Context manager to simplify error handling for connecting to ceph."""
      def __init__(self, driver, pool=None):
          self.driver = driver
          self.cluster, self.ioctx = driver._connect_to_rados(pool)
  
      def __enter__(self):
          return self
  
      def __exit__(self, type_, value, traceback):
          self.driver._disconnect_from_rados(self.cluster, self.ioctx)
  
      @property
      def features(self):
          features = self.cluster.conf_get('rbd_default_features')
          if ((features is None) or (int(features) == 0)):
              features = self.driver.rbd.RBD_FEATURE_LAYERING
          return int(features)
  
  
  @interface.volumedriver
  class RBDDriver(driver.TransferVD, driver.ExtendVD,
                  driver.CloneableImageVD, driver.SnapshotVD,
                  driver.MigrateVD, driver.ManageableVD, driver.BaseVD):
      """Implements RADOS block device (RBD) volume commands."""
  
      VERSION = '1.2.0'
  
      # ThirdPartySystems wiki page
      CI_WIKI_NAME = "Cinder_Jenkins"
  
      def __init__(self, *args, **kwargs):
          super(RBDDriver, self).__init__(*args, **kwargs)
          self.configuration.append_config_values(RBD_OPTS)
          self._stats = {}
          # allow overrides for testing
          self.rados = kwargs.get('rados', rados)
          self.rbd = kwargs.get('rbd', rbd)
  
          # All string args used with librbd must be None or utf-8 otherwise
          # librbd will break.
          for attr in ['rbd_cluster_name', 'rbd_user',
                       'rbd_ceph_conf', 'rbd_pool']:
              val = getattr(self.configuration, attr)
              if val is not None:
                  setattr(self.configuration, attr, utils.convert_str(val))
  
      def check_for_setup_error(self):
          """Returns an error if prerequisites aren't met."""
          if rados is None:
              msg = _('rados and rbd python libraries not found')
              raise exception.VolumeBackendAPIException(data=msg)
  
          for attr in ['rbd_cluster_name', 'rbd_pool']:
              val = getattr(self.configuration, attr)
              if not val:
                  raise exception.InvalidConfigurationValue(option=attr,
                                                            value=val)
          # NOTE: Checking connection to ceph
          # RADOSClient __init__ method invokes _connect_to_rados
          # so no need to check for self.rados.Error here.
          with RADOSClient(self):
              pass
  
      def RBDProxy(self):
          return tpool.Proxy(self.rbd.RBD())
  
      def _ceph_args(self):
          args = []
          if self.configuration.rbd_user:
              args.extend(['--id', self.configuration.rbd_user])
          if self.configuration.rbd_ceph_conf:
              args.extend(['--conf', self.configuration.rbd_ceph_conf])
          if self.configuration.rbd_cluster_name:
              args.extend(['--cluster', self.configuration.rbd_cluster_name])
          return args
  
      @utils.retry(exception.VolumeBackendAPIException,
                   CONF.rados_connection_interval,
                   CONF.rados_connection_retries)
      def _connect_to_rados(self, pool=None):
          LOG.debug("opening connection to ceph cluster (timeout=%s).",
                    self.configuration.rados_connect_timeout)
  
          client = self.rados.Rados(
              rados_id=self.configuration.rbd_user,
              clustername=self.configuration.rbd_cluster_name,
              conffile=self.configuration.rbd_ceph_conf)
          if pool is not None:
              pool = utils.convert_str(pool)
          else:
              pool = self.configuration.rbd_pool
  
          try:
              timeout = self.configuration.rados_connect_timeout
              if timeout >= 0:
                  timeout = six.text_type(timeout)
                  client.conf_set('rados_osd_op_timeout', timeout)
                  client.conf_set('rados_mon_op_timeout', timeout)
                  client.conf_set('client_mount_timeout', timeout)
  
              client.connect()
              ioctx = client.open_ioctx(pool)
              return client, ioctx
          except self.rados.Error:
              msg = _("Error connecting to ceph cluster.")
              LOG.exception(msg)
              client.shutdown()
              raise exception.VolumeBackendAPIException(data=msg)
  
      def _disconnect_from_rados(self, client, ioctx):
          # closing an ioctx cannot raise an exception
          ioctx.close()
          client.shutdown()
  
      def _get_backup_snaps(self, rbd_image):
          """Get list of any backup snapshots that exist on this volume.
  
          There should only ever be one but accept all since they need to be
          deleted before the volume can be.
          """
          # NOTE(dosaboy): we do the import here otherwise we get import conflict
          # issues between the rbd driver and the ceph backup driver. These
          # issues only seem to occur when NOT using them together and are
          # triggered when the ceph backup driver imports the rbd volume driver.
          from cinder.backup.drivers import ceph
          return ceph.CephBackupDriver.get_backup_snaps(rbd_image)
  
      def _get_mon_addrs(self):
          args = ['ceph', 'mon', 'dump', '--format=json']
          args.extend(self._ceph_args())
          out, _ = self._execute(*args)
          lines = out.split('\n')
          if lines[0].startswith('dumped monmap epoch'):
              lines = lines[1:]
          monmap = json.loads('\n'.join(lines))
          addrs = [mon['addr'] for mon in monmap['mons']]
          hosts = []
          ports = []
          for addr in addrs:
              host_port = addr[:addr.rindex('/')]
              host, port = host_port.rsplit(':', 1)
              hosts.append(host.strip('[]'))
              ports.append(port)
          return hosts, ports
  
      def _update_volume_stats(self):
          stats = {
              'vendor_name': 'Open Source',
              'driver_version': self.VERSION,
              'storage_protocol': 'ceph',
              'total_capacity_gb': 'unknown',
              'free_capacity_gb': 'unknown',
              'reserved_percentage': 0,
              'multiattach': False,
          }
          backend_name = self.configuration.safe_get('volume_backend_name')
          stats['volume_backend_name'] = backend_name or 'RBD'
  
          try:
              with RADOSClient(self) as client:
                  ret, outbuf, _outs = client.cluster.mon_command(
                      '{"prefix":"df", "format":"json"}', '')
                  if ret != 0:
                      LOG.warning(_LW('Unable to get rados pool stats.'))
                  else:
                      outbuf = json.loads(outbuf)
                      pool_stats = [pool for pool in outbuf['pools'] if
                                    pool['name'] ==
                                    self.configuration.rbd_pool][0]['stats']
                      stats['free_capacity_gb'] = round((float(
                          pool_stats['max_avail']) / units.Gi), 2)
                      used_capacity_gb = float(
                          pool_stats['bytes_used']) / units.Gi
                      stats['total_capacity_gb'] = round(
                          (stats['free_capacity_gb'] + used_capacity_gb), 2)
          except self.rados.Error:
              # just log and return unknown capacities
              LOG.exception(_LE('error refreshing volume stats'))
          self._stats = stats
  
      def get_volume_stats(self, refresh=False):
          """Return the current state of the volume service.
  
          If 'refresh' is True, run the update first.
          """
          if refresh:
              self._update_volume_stats()
          return self._stats
  
      def _get_clone_depth(self, client, volume_name, depth=0):
          """Returns the number of ancestral clones of the given volume."""
          parent_volume = self.rbd.Image(client.ioctx, volume_name)
          try:
              _pool, parent, _snap = self._get_clone_info(parent_volume,
                                                          volume_name)
          finally:
              parent_volume.close()
  
          if not parent:
              return depth
  
          # If clone depth was reached, flatten should have occurred so if it has
          # been exceeded then something has gone wrong.
          if depth > self.configuration.rbd_max_clone_depth:
              raise Exception(_("clone depth exceeds limit of %s") %
                              (self.configuration.rbd_max_clone_depth))
  
          return self._get_clone_depth(client, parent, depth + 1)
  
      def create_cloned_volume(self, volume, src_vref):
          """Create a cloned volume from another volume.
  
          Since we are cloning from a volume and not a snapshot, we must first
          create a snapshot of the source volume.
  
          The user has the option to limit how long a volume's clone chain can be
          by setting rbd_max_clone_depth. If a clone is made of another clone
          and that clone has rbd_max_clone_depth clones behind it, the source
          volume will be flattened.
          """
          src_name = utils.convert_str(src_vref.name)
          dest_name = utils.convert_str(volume.name)
          flatten_parent = False
  
          # Do full copy if requested
          if self.configuration.rbd_max_clone_depth <= 0:
              with RBDVolumeProxy(self, src_name, read_only=True) as vol:
                  vol.copy(vol.ioctx, dest_name)
  
              return
  
          # Otherwise do COW clone.
          with RADOSClient(self) as client:
              depth = self._get_clone_depth(client, src_name)
              # If source volume is a clone and rbd_max_clone_depth reached,
              # flatten the source before cloning. Zero rbd_max_clone_depth means
              # infinite is allowed.
              if depth == self.configuration.rbd_max_clone_depth:
                  LOG.debug("maximum clone depth (%d) has been reached - "
                            "flattening source volume",
                            self.configuration.rbd_max_clone_depth)
                  flatten_parent = True
  
              src_volume = self.rbd.Image(client.ioctx, src_name)
              try:
                  # First flatten source volume if required.
                  if flatten_parent:
                      _pool, parent, snap = self._get_clone_info(src_volume,
                                                                 src_name)
                      # Flatten source volume
                      LOG.debug("flattening source volume %s", src_name)
                      src_volume.flatten()
                      # Delete parent clone snap
                      parent_volume = self.rbd.Image(client.ioctx, parent)
                      try:
                          parent_volume.unprotect_snap(snap)
                          parent_volume.remove_snap(snap)
                      finally:
                          parent_volume.close()
  
                  # Create new snapshot of source volume
                  clone_snap = "%s.clone_snap" % dest_name
                  LOG.debug("creating snapshot='%s'", clone_snap)
                  src_volume.create_snap(clone_snap)
                  src_volume.protect_snap(clone_snap)
              except Exception:
                  # Only close if exception since we still need it.
                  src_volume.close()
                  raise
  
              # Now clone source volume snapshot
              try:
                  LOG.debug("cloning '%(src_vol)s@%(src_snap)s' to "
                            "'%(dest)s'",
                            {'src_vol': src_name, 'src_snap': clone_snap,
                             'dest': dest_name})
                  self.RBDProxy().clone(client.ioctx, src_name, clone_snap,
                                        client.ioctx, dest_name,
                                        features=client.features)
              except Exception:
                  src_volume.unprotect_snap(clone_snap)
                  src_volume.remove_snap(clone_snap)
                  raise
              finally:
                  src_volume.close()
  
          if volume.size != src_vref.size:
              LOG.debug("resize volume '%(dst_vol)s' from %(src_size)d to "
                        "%(dst_size)d",
                        {'dst_vol': volume.name, 'src_size': src_vref.size,
                         'dst_size': volume.size})
              self._resize(volume)
  
          LOG.debug("clone created successfully")
  
      def create_volume(self, volume):
          """Creates a logical volume."""
          size = int(volume.size) * units.Gi
  
          LOG.debug("creating volume '%s'", volume.name)
  
          chunk_size = self.configuration.rbd_store_chunk_size * units.Mi
          order = int(math.log(chunk_size, 2))
  
          with RADOSClient(self) as client:
              self.RBDProxy().create(client.ioctx,
                                     utils.convert_str(volume.name),
                                     size,
                                     order,
                                     old_format=False,
                                     features=client.features)
  
      def _flatten(self, pool, volume_name):
          LOG.debug('flattening %(pool)s/%(img)s',
                    dict(pool=pool, img=volume_name))
          with RBDVolumeProxy(self, volume_name, pool) as vol:
              vol.flatten()
  
      def _clone(self, volume, src_pool, src_image, src_snap):
          LOG.debug('cloning %(pool)s/%(img)s@%(snap)s to %(dst)s',
                    dict(pool=src_pool, img=src_image, snap=src_snap,
                         dst=volume.name))
  
          chunk_size = self.configuration.rbd_store_chunk_size * units.Mi
          order = int(math.log(chunk_size, 2))
  
          with RADOSClient(self, src_pool) as src_client:
              with RADOSClient(self) as dest_client:
                  self.RBDProxy().clone(src_client.ioctx,
                                        utils.convert_str(src_image),
                                        utils.convert_str(src_snap),
                                        dest_client.ioctx,
                                        utils.convert_str(volume.name),
                                        features=src_client.features,
                                        order=order)
  
      def _resize(self, volume, **kwargs):
          size = kwargs.get('size', None)
          if not size:
              size = int(volume.size) * units.Gi
  
          with RBDVolumeProxy(self, volume.name) as vol:
              vol.resize(size)
  
      def create_volume_from_snapshot(self, volume, snapshot):
          """Creates a volume from a snapshot."""
          self._clone(volume, self.configuration.rbd_pool,
                      snapshot.volume_name, snapshot.name)
          if self.configuration.rbd_flatten_volume_from_snapshot:
              self._flatten(self.configuration.rbd_pool, volume.name)
          if int(volume.size):
              self._resize(volume)
  
      def _delete_backup_snaps(self, rbd_image):
          backup_snaps = self._get_backup_snaps(rbd_image)
          if backup_snaps:
              for snap in backup_snaps:
                  rbd_image.remove_snap(snap['name'])
          else:
              LOG.debug("volume has no backup snaps")
  
      def _get_clone_info(self, volume, volume_name, snap=None):
          """If volume is a clone, return its parent info.
  
          Returns a tuple of (pool, parent, snap). A snapshot may optionally be
          provided for the case where a cloned volume has been flattened but it's
          snapshot still depends on the parent.
          """
          try:
              if snap:
                  volume.set_snap(snap)
              pool, parent, parent_snap = tuple(volume.parent_info())
              if snap:
                  volume.set_snap(None)
              # Strip the tag off the end of the volume name since it will not be
              # in the snap name.
              if volume_name.endswith('.deleted'):
                  volume_name = volume_name[:-len('.deleted')]
              # Now check the snap name matches.
              if parent_snap == "%s.clone_snap" % volume_name:
                  return pool, parent, parent_snap
          except self.rbd.ImageNotFound:
              LOG.debug("Volume %s is not a clone.", volume_name)
              volume.set_snap(None)
  
          return (None, None, None)
  
      def _get_children_info(self, volume, snap):
          """List children for the given snapshot of a volume(image).
  
          Returns a list of (pool, image).
          """
  
          children_list = []
  
          if snap:
              volume.set_snap(snap)
              children_list = volume.list_children()
              volume.set_snap(None)
  
          return children_list
  
      def _delete_clone_parent_refs(self, client, parent_name, parent_snap):
          """Walk back up the clone chain and delete references.
  
          Deletes references i.e. deleted parent volumes and snapshots.
          """
          parent_rbd = self.rbd.Image(client.ioctx, parent_name)
          parent_has_snaps = False
          try:
              # Check for grandparent
              _pool, g_parent, g_parent_snap = self._get_clone_info(parent_rbd,
                                                                    parent_name,
                                                                    parent_snap)
  
              LOG.debug("deleting parent snapshot %s", parent_snap)
              parent_rbd.unprotect_snap(parent_snap)
              parent_rbd.remove_snap(parent_snap)
  
              parent_has_snaps = bool(list(parent_rbd.list_snaps()))
          finally:
              parent_rbd.close()
  
          # If parent has been deleted in Cinder, delete the silent reference and
          # keep walking up the chain if it is itself a clone.
          if (not parent_has_snaps) and parent_name.endswith('.deleted'):
              LOG.debug("deleting parent %s", parent_name)
              self.RBDProxy().remove(client.ioctx, parent_name)
  
              # Now move up to grandparent if there is one
              if g_parent:
                  self._delete_clone_parent_refs(client, g_parent, g_parent_snap)
  
      def delete_volume(self, volume):
          """Deletes a logical volume."""
          # NOTE(dosaboy): this was broken by commit cbe1d5f. Ensure names are
          #                utf-8 otherwise librbd will barf.
          volume_name = utils.convert_str(volume.name)
          with RADOSClient(self) as client:
              try:
                  rbd_image = self.rbd.Image(client.ioctx, volume_name)
              except self.rbd.ImageNotFound:
                  LOG.info(_LI("volume %s no longer exists in backend"),
                           volume_name)
                  return
  
              clone_snap = None
              parent = None
  
              # Ensure any backup snapshots are deleted
              self._delete_backup_snaps(rbd_image)
  
              # If the volume has non-clone snapshots this delete is expected to
              # raise VolumeIsBusy so do so straight away.
              try:
                  snaps = rbd_image.list_snaps()
                  for snap in snaps:
                      if snap['name'].endswith('.clone_snap'):
                          LOG.debug("volume has clone snapshot(s)")
                          # We grab one of these and use it when fetching parent
                          # info in case the volume has been flattened.
                          clone_snap = snap['name']
                          break
  
                      raise exception.VolumeIsBusy(volume_name=volume_name)
  
                  # Determine if this volume is itself a clone
                  _pool, parent, parent_snap = self._get_clone_info(rbd_image,
                                                                    volume_name,
                                                                    clone_snap)
              finally:
                  rbd_image.close()
  
              @utils.retry(self.rbd.ImageBusy,
                           self.configuration.rados_connection_interval,
                           self.configuration.rados_connection_retries)
              def _try_remove_volume(client, volume_name):
                  self.RBDProxy().remove(client.ioctx, volume_name)
  
              if clone_snap is None:
                  LOG.debug("deleting rbd volume %s", volume_name)
                  try:
                      _try_remove_volume(client, volume_name)
                  except self.rbd.ImageBusy:
                      msg = (_("ImageBusy error raised while deleting rbd "
                               "volume. This may have been caused by a "
                               "connection from a client that has crashed and, "
                               "if so, may be resolved by retrying the delete "
                               "after 30 seconds has elapsed."))
                      LOG.warning(msg)
                      # Now raise this so that volume stays available so that we
                      # delete can be retried.
                      raise exception.VolumeIsBusy(msg, volume_name=volume_name)
                  except self.rbd.ImageNotFound:
                      LOG.info(_LI("RBD volume %s not found, allowing delete "
                                   "operation to proceed."), volume_name)
                      return
  
                  # If it is a clone, walk back up the parent chain deleting
                  # references.
                  if parent:
                      LOG.debug("volume is a clone so cleaning references")
                      self._delete_clone_parent_refs(client, parent, parent_snap)
              else:
                  # If the volume has copy-on-write clones we will not be able to
                  # delete it. Instead we will keep it as a silent volume which
                  # will be deleted when it's snapshot and clones are deleted.
                  new_name = "%s.deleted" % (volume_name)
                  self.RBDProxy().rename(client.ioctx, volume_name, new_name)
  
      def create_snapshot(self, snapshot):
          """Creates an rbd snapshot."""
          with RBDVolumeProxy(self, snapshot.volume_name) as volume:
              snap = utils.convert_str(snapshot.name)
              volume.create_snap(snap)
              volume.protect_snap(snap)
  
      def delete_snapshot(self, snapshot):
          """Deletes an rbd snapshot."""
          # NOTE(dosaboy): this was broken by commit cbe1d5f. Ensure names are
          #                utf-8 otherwise librbd will barf.
          volume_name = utils.convert_str(snapshot.volume_name)
          snap_name = utils.convert_str(snapshot.name)
  
          with RBDVolumeProxy(self, volume_name) as volume:
              try:
                  volume.unprotect_snap(snap_name)
              except self.rbd.InvalidArgument:
                  LOG.info(
                      _LI("InvalidArgument: Unable to unprotect snapshot %s."),
                      snap_name)
              except self.rbd.ImageNotFound:
                  LOG.info(
                      _LI("ImageNotFound: Unable to unprotect snapshot %s."),
                      snap_name)
              except self.rbd.ImageBusy:
                  children_list = self._get_children_info(volume, snap_name)
  
                  if children_list:
                      for (pool, image) in children_list:
                          LOG.info(_LI('Image %(pool)s/%(image)s is dependent '
                                       'on the snapshot %(snap)s.'),
                                   {'pool': pool,
                                    'image': image,
                                    'snap': snap_name})
  
                  raise exception.SnapshotIsBusy(snapshot_name=snap_name)
              try:
                  volume.remove_snap(snap_name)
              except self.rbd.ImageNotFound:
                  LOG.info(_LI("Snapshot %s does not exist in backend."),
                           snap_name)
  
      def retype(self, context, volume, new_type, diff, host):
          """Retypes a volume, allow Qos and extra_specs change."""
  
          # No need to check encryption, extra_specs and Qos here as:
          # encryptions have been checked as same.
          # extra_specs are not used in the driver.
          # Qos settings are not used in the driver.
          LOG.debug('RBD retype called for volume %s. No action '
                    'required for RBD volumes.', volume.id)
          return True
  
      def ensure_export(self, context, volume):
          """Synchronously recreates an export for a logical volume."""
          pass
  
      def create_export(self, context, volume, connector):
          """Exports the volume."""
          pass
  
      def remove_export(self, context, volume):
          """Removes an export for a logical volume."""
          pass
  
      def initialize_connection(self, volume, connector):
          hosts, ports = self._get_mon_addrs()
          data = {
              'driver_volume_type': 'rbd',
              'data': {
                  'name': '%s/%s' % (self.configuration.rbd_pool,
                                     volume.name),
                  'hosts': hosts,
                  'ports': ports,
                  'cluster_name': self.configuration.rbd_cluster_name,
                  'auth_enabled': (self.configuration.rbd_user is not None),
                  'auth_username': self.configuration.rbd_user,
                  'secret_type': 'ceph',
                  'secret_uuid': self.configuration.rbd_secret_uuid,
                  'volume_id': volume.id,
              }
          }
          LOG.debug('connection data: %s', data)
          return data
  
      def terminate_connection(self, volume, connector, **kwargs):
          pass
  
      def _parse_location(self, location):
          prefix = 'rbd://'
          if not location.startswith(prefix):
              reason = _('Not stored in rbd')
              raise exception.ImageUnacceptable(image_id=location, reason=reason)
          pieces = [urllib.parse.unquote(loc)
                    for loc in location[len(prefix):].split('/')]
          if any(map(lambda p: p == '', pieces)):
              reason = _('Blank components')
              raise exception.ImageUnacceptable(image_id=location, reason=reason)
          if len(pieces) != 4:
              reason = _('Not an rbd snapshot')
              raise exception.ImageUnacceptable(image_id=location, reason=reason)
          return pieces
  
      def _get_fsid(self):
          with RADOSClient(self) as client:
              return client.cluster.get_fsid()
  
      def _is_cloneable(self, image_location, image_meta):
          try:
              fsid, pool, image, snapshot = self._parse_location(image_location)
          except exception.ImageUnacceptable as e:
              LOG.debug('not cloneable: %s.', e)
              return False
  
          if self._get_fsid() != fsid:
              LOG.debug('%s is in a different ceph cluster.', image_location)
              return False
  
          if image_meta['disk_format'] != 'raw':
              LOG.debug("rbd image clone requires image format to be "
                        "'raw' but image %(image)s is '%(format)s'",
                        {"image": image_location,
                         "format": image_meta['disk_format']})
              return False
  
          # check that we can read the image
          try:
              with RBDVolumeProxy(self, image,
                                  pool=pool,
                                  snapshot=snapshot,
                                  read_only=True):
                  return True
          except self.rbd.Error as e:
              LOG.debug('Unable to open image %(loc)s: %(err)s.',
                        dict(loc=image_location, err=e))
              return False
  
      def clone_image(self, context, volume,
                      image_location, image_meta,
                      image_service):
          if image_location:
              # Note: image_location[0] is glance image direct_url.
              # image_location[1] contains the list of all locations (including
              # direct_url) or None if show_multiple_locations is False in
              # glance configuration.
              if image_location[1]:
                  url_locations = [location['url'] for
                                   location in image_location[1]]
              else:
                  url_locations = [image_location[0]]
  
              # iterate all locations to look for a cloneable one.
              for url_location in url_locations:
                  if url_location and self._is_cloneable(
                          url_location, image_meta):
                      _prefix, pool, image, snapshot = \
                          self._parse_location(url_location)
                      self._clone(volume, pool, image, snapshot)
                      self._resize(volume)
                      return {'provider_location': None}, True
          return ({}, False)
  
      def _image_conversion_dir(self):
          tmpdir = (self.configuration.volume_tmp_dir or
                    CONF.image_conversion_dir or
                    tempfile.gettempdir())
  
          if tmpdir == self.configuration.volume_tmp_dir:
              LOG.warning(_LW('volume_tmp_dir is now deprecated, please use '
                              'image_conversion_dir.'))
  
          # ensure temporary directory exists
          if not os.path.exists(tmpdir):
              os.makedirs(tmpdir)
  
          return tmpdir
  
      def copy_image_to_volume(self, context, volume, image_service, image_id):
  
          tmp_dir = self._image_conversion_dir()
  
          with tempfile.NamedTemporaryFile(dir=tmp_dir) as tmp:
              image_utils.fetch_to_raw(context, image_service, image_id,
                                       tmp.name,
                                       self.configuration.volume_dd_blocksize,
                                       size=volume.size)
  
              self.delete_volume(volume)
  
              chunk_size = self.configuration.rbd_store_chunk_size * units.Mi
              order = int(math.log(chunk_size, 2))
              # keep using the command line import instead of librbd since it
              # detects zeroes to preserve sparseness in the image
              args = ['rbd', 'import',
                      '--pool', self.configuration.rbd_pool,
                      '--order', order,
                      tmp.name, volume.name,
                      '--new-format']
              args.extend(self._ceph_args())
              self._try_execute(*args)
          self._resize(volume)
  
      def copy_volume_to_image(self, context, volume, image_service, image_meta):
          tmp_dir = self._image_conversion_dir()
          tmp_file = os.path.join(tmp_dir,
                                  volume.name + '-' + image_meta['id'])
          with fileutils.remove_path_on_error(tmp_file):
              args = ['rbd', 'export',
                      '--pool', self.configuration.rbd_pool,
                      volume.name, tmp_file]
              args.extend(self._ceph_args())
              self._try_execute(*args)
              image_utils.upload_volume(context, image_service,
                                        image_meta, tmp_file)
          os.unlink(tmp_file)
  
      def backup_volume(self, context, backup, backup_service):
          """Create a new backup from an existing volume."""
          volume = self.db.volume_get(context, backup.volume_id)
  
          with RBDVolumeProxy(self, volume.name,
                              self.configuration.rbd_pool) as rbd_image:
              rbd_meta = RBDImageMetadata(rbd_image, self.configuration.rbd_pool,
                                          self.configuration.rbd_user,
                                          self.configuration.rbd_ceph_conf)
              rbd_fd = RBDImageIOWrapper(rbd_meta)
              backup_service.backup(backup, rbd_fd)
  
          LOG.debug("volume backup complete.")
  
      def restore_backup(self, context, backup, volume, backup_service):
          """Restore an existing backup to a new or existing volume."""
          with RBDVolumeProxy(self, volume.name,
                              self.configuration.rbd_pool) as rbd_image:
              rbd_meta = RBDImageMetadata(rbd_image, self.configuration.rbd_pool,
                                          self.configuration.rbd_user,
                                          self.configuration.rbd_ceph_conf)
              rbd_fd = RBDImageIOWrapper(rbd_meta)
              backup_service.restore(backup, volume.id, rbd_fd)
  
          LOG.debug("volume restore complete.")
  
      def extend_volume(self, volume, new_size):
          """Extend an existing volume."""
          old_size = volume.size
  
          try:
              size = int(new_size) * units.Gi
              self._resize(volume, size=size)
          except Exception:
              msg = _('Failed to Extend Volume '
                      '%(volname)s') % {'volname': volume.name}
              LOG.error(msg)
              raise exception.VolumeBackendAPIException(data=msg)
  
          LOG.debug("Extend volume from %(old_size)s GB to %(new_size)s GB.",
                    {'old_size': old_size, 'new_size': new_size})
  
      def manage_existing(self, volume, existing_ref):
          """Manages an existing image.
  
          Renames the image name to match the expected name for the volume.
          Error checking done by manage_existing_get_size is not repeated.
  
          :param volume:
              volume ref info to be set
          :param existing_ref:
              existing_ref is a dictionary of the form:
              {'source-name': <name of rbd image>}
          """
          # Raise an exception if we didn't find a suitable rbd image.
          with RADOSClient(self) as client:
              rbd_name = existing_ref['source-name']
              self.RBDProxy().rename(client.ioctx,
                                     utils.convert_str(rbd_name),
                                     utils.convert_str(volume.name))
  
      def manage_existing_get_size(self, volume, existing_ref):
          """Return size of an existing image for manage_existing.
  
          :param volume:
              volume ref info to be set
          :param existing_ref:
              existing_ref is a dictionary of the form:
              {'source-name': <name of rbd image>}
          """
  
          # Check that the reference is valid
          if 'source-name' not in existing_ref:
              reason = _('Reference must contain source-name element.')
              raise exception.ManageExistingInvalidReference(
                  existing_ref=existing_ref, reason=reason)
  
          rbd_name = utils.convert_str(existing_ref['source-name'])
  
          with RADOSClient(self) as client:
              # Raise an exception if we didn't find a suitable rbd image.
              try:
                  rbd_image = self.rbd.Image(client.ioctx, rbd_name)
              except self.rbd.ImageNotFound:
                  kwargs = {'existing_ref': rbd_name,
                            'reason': 'Specified rbd image does not exist.'}
                  raise exception.ManageExistingInvalidReference(**kwargs)
  
              image_size = rbd_image.size()
              rbd_image.close()
  
              # RBD image size is returned in bytes.  Attempt to parse
              # size as a float and round up to the next integer.
              try:
                  convert_size = int(math.ceil(float(image_size) / units.Gi))
                  return convert_size
              except ValueError:
                  exception_message = (_("Failed to manage existing volume "
                                         "%(name)s, because reported size "
                                         "%(size)s was not a floating-point"
                                         " number.")
                                       % {'name': rbd_name,
                                          'size': image_size})
                  raise exception.VolumeBackendAPIException(
                      data=exception_message)
  
      def unmanage(self, volume):
          pass
  
      def update_migrated_volume(self, ctxt, volume, new_volume,
                                 original_volume_status):
          """Return model update from RBD for migrated volume.
  
          This method should rename the back-end volume name(id) on the
          destination host back to its original name(id) on the source host.
  
          :param ctxt: The context used to run the method update_migrated_volume
          :param volume: The original volume that was migrated to this backend
          :param new_volume: The migration volume object that was created on
                             this backend as part of the migration process
          :param original_volume_status: The status of the original volume
          :returns: model_update to update DB with any needed changes
          """
          name_id = None
          provider_location = None
  
          existing_name = CONF.volume_name_template % new_volume.id
          wanted_name = CONF.volume_name_template % volume.id
          with RADOSClient(self) as client:
              try:
                  self.RBDProxy().rename(client.ioctx,
                                         utils.convert_str(existing_name),
                                         utils.convert_str(wanted_name))
              except self.rbd.ImageNotFound:
                  LOG.error(_LE('Unable to rename the logical volume '
                                'for volume %s.'), volume.id)
                  # If the rename fails, _name_id should be set to the new
                  # volume id and provider_location should be set to the
                  # one from the new volume as well.
                  name_id = new_volume._name_id or new_volume.id
                  provider_location = new_volume['provider_location']
          return {'_name_id': name_id, 'provider_location': provider_location}
  
      def migrate_volume(self, context, volume, host):
          return (False, None)
  