# Copyright (c) 2014 Hitachi Data Systems, Inc.
# All Rights Reserved.
#
#    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.

"""
Volume driver for HDS HNAS NFS storage.
"""

import math
import os
import re
import six
import socket
import time
from xml.etree import ElementTree as ETree

from oslo_concurrency import processutils
from oslo_config import cfg
from oslo_log import log as logging
from oslo_utils import units

from cinder import exception
from cinder.i18n import _, _LE, _LI
from cinder.image import image_utils
from cinder import utils as cutils
from cinder.volume.drivers.hitachi import hnas_backend
from cinder.volume.drivers import nfs
from cinder.volume import utils
from cinder.volume import volume_types


HDS_HNAS_NFS_VERSION = '4.1.0'

LOG = logging.getLogger(__name__)

NFS_OPTS = [
    cfg.StrOpt('hds_hnas_nfs_config_file',
               default='/opt/hds/hnas/cinder_nfs_conf.xml',
               help='Configuration file for HDS NFS cinder plugin'), ]

CONF = cfg.CONF
CONF.register_opts(NFS_OPTS)

HNAS_DEFAULT_CONFIG = {'hnas_cmd': 'ssc', 'ssh_port': '22'}


def _xml_read(root, element, check=None):
    """Read an xml element."""

    val = root.findtext(element)

    # mandatory parameter not found
    if val is None and check:
        raise exception.ParameterNotFound(param=element)

    # tag not found
    if val is None:
        return None

    svc_tag_pattern = re.compile("svc_.$")
    # tag found but empty parameter.
    if not val.strip():
        if svc_tag_pattern.search(element):
            return ""
        raise exception.ParameterNotFound(param=element)

    LOG.debug(_LI("%(element)s: %(val)s"),
              {'element': element,
               'val': val if element != 'password' else '***'})

    return val.strip()


def _read_config(xml_config_file):
    """Read hds driver specific xml config file.

    :param xml_config_file: string filename containing XML configuration
    """

    if not os.access(xml_config_file, os.R_OK):
        msg = (_("Can't open config file: %s") % xml_config_file)
        raise exception.NotFound(message=msg)

    try:
        root = ETree.parse(xml_config_file).getroot()
    except Exception:
        msg = (_("Error parsing config file: %s") % xml_config_file)
        raise exception.ConfigNotFound(message=msg)

    # mandatory parameters
    config = {}
    arg_prereqs = ['mgmt_ip0', 'username']
    for req in arg_prereqs:
        config[req] = _xml_read(root, req, True)

    # optional parameters
    opt_parameters = ['hnas_cmd', 'ssh_enabled', 'cluster_admin_ip0']
    for req in opt_parameters:
        config[req] = _xml_read(root, req)

    if config['ssh_enabled'] == 'True':
        config['ssh_private_key'] = _xml_read(root, 'ssh_private_key', True)
        config['password'] = _xml_read(root, 'password')
        config['ssh_port'] = _xml_read(root, 'ssh_port')
        if config['ssh_port'] is None:
            config['ssh_port'] = HNAS_DEFAULT_CONFIG['ssh_port']
    else:
        # password is mandatory when not using SSH
        config['password'] = _xml_read(root, 'password', True)

    if config['hnas_cmd'] is None:
        config['hnas_cmd'] = HNAS_DEFAULT_CONFIG['hnas_cmd']

    config['hdp'] = {}
    config['services'] = {}

    # min one needed
    for svc in ['svc_0', 'svc_1', 'svc_2', 'svc_3']:
        if _xml_read(root, svc) is None:
            continue
        service = {'label': svc}

        # none optional
        for arg in ['volume_type', 'hdp']:
            service[arg] = _xml_read(root, svc + '/' + arg, True)
        config['services'][service['volume_type']] = service
        config['hdp'][service['hdp']] = service['hdp']

    # at least one service required!
    if config['services'].keys() is None:
        raise exception.ParameterNotFound(param="No service found")

    return config


def factory_bend(drv_config):
    """Factory over-ride in self-tests."""

    return hnas_backend.HnasBackend(drv_config)


class HDSNFSDriver(nfs.NfsDriver):
    """Base class for Hitachi NFS driver.

    Executes commands relating to Volumes.

    Version 1.0.0: Initial driver version
    Version 2.2.0: Added support to SSH authentication
    Version 3.0.0: Added pool aware scheduling
    Version 4.0.0: Added manage/unmanage features
    Version 4.1.0: Fixed XML parser checks on blank options
    """

    def __init__(self, *args, **kwargs):
        # NOTE(vish): db is set by Manager
        self._execute = None
        self.context = None
        self.configuration = kwargs.get('configuration', None)

        if self.configuration:
            self.configuration.append_config_values(NFS_OPTS)
            self.config = _read_config(
                self.configuration.hds_hnas_nfs_config_file)

        super(HDSNFSDriver, self).__init__(*args, **kwargs)
        self.bend = factory_bend(self.config)

    def _array_info_get(self):
        """Get array parameters."""

        out = self.bend.get_version(self.config['hnas_cmd'],
                                    HDS_HNAS_NFS_VERSION,
                                    self.config['mgmt_ip0'],
                                    self.config['username'],
                                    self.config['password'])

        inf = out.split()
        return inf[1], 'nfs_' + inf[1], inf[6]

    def _id_to_vol(self, volume_id):
        """Given the volume id, retrieve the volume object from database.

        :param volume_id: string volume id
        """

        vol = self.db.volume_get(self.context, volume_id)

        return vol

    def _get_service(self, volume):
        """Get service parameters.

        Get the available service parameters for a given volume using
        its type.

        :param volume: dictionary volume reference
        """

        LOG.debug("_get_service: volume: %s", volume)
        label = utils.extract_host(volume['host'], level='pool')

        if label in self.config['services'].keys():
            svc = self.config['services'][label]
            LOG.info(_LI("Get service: %(lbl)s->%(svc)s"),
                     {'lbl': label, 'svc': svc['fslabel']})
            service = (svc['hdp'], svc['path'], svc['fslabel'])
        else:
            LOG.info(_LI("Available services: %s"),
                     self.config['services'].keys())
            LOG.error(_LE("No configuration found for service: %s"),
                      label)
            raise exception.ParameterNotFound(param=label)

        return service

    def extend_volume(self, volume, new_size):
        """Extend an existing volume.

        :param volume: dictionary volume reference
        :param new_size: int size in GB to extend
        """

        nfs_mount = self._get_provider_location(volume['id'])
        path = self._get_volume_path(nfs_mount, volume['name'])

        # Resize the image file on share to new size.
        LOG.debug("Checking file for resize")

        if self._is_file_size_equal(path, new_size):
            return
        else:
            LOG.info(_LI("Resizing file to %sG"), new_size)
            image_utils.resize_image(path, new_size)
            if self._is_file_size_equal(path, new_size):
                LOG.info(_LI("LUN %(id)s extended to %(size)s GB."),
                         {'id': volume['id'], 'size': new_size})
                return
            else:
                raise exception.InvalidResults(
                    _("Resizing image file failed."))

    def _is_file_size_equal(self, path, size):
        """Checks if file size at path is equal to size."""

        data = image_utils.qemu_img_info(path)
        virt_size = data.virtual_size / units.Gi

        if virt_size == size:
            return True
        else:
            return False

    def create_volume_from_snapshot(self, volume, snapshot):
        """Creates a volume from a snapshot."""

        LOG.debug("create_volume_from %s", volume)
        vol_size = volume['size']
        snap_size = snapshot['volume_size']

        if vol_size != snap_size:
            msg = _("Cannot create volume of size %(vol_size)s from "
                    "snapshot of size %(snap_size)s")
            msg_fmt = {'vol_size': vol_size, 'snap_size': snap_size}
            raise exception.CinderException(msg % msg_fmt)

        self._clone_volume(snapshot['name'],
                           volume['name'],
                           snapshot['volume_id'])
        share = self._get_volume_location(snapshot['volume_id'])

        return {'provider_location': share}

    def create_snapshot(self, snapshot):
        """Create a snapshot.

        :param snapshot: dictionary snapshot reference
        """

        self._clone_volume(snapshot['volume_name'],
                           snapshot['name'],
                           snapshot['volume_id'])
        share = self._get_volume_location(snapshot['volume_id'])
        LOG.debug('Share: %s', share)

        # returns the mount point (not path)
        return {'provider_location': share}

    def delete_snapshot(self, snapshot):
        """Deletes a snapshot.

        :param snapshot: dictionary snapshot reference
        """

        nfs_mount = self._get_provider_location(snapshot['volume_id'])

        if self._volume_not_present(nfs_mount, snapshot['name']):
            return True

        self._execute('rm', self._get_volume_path(nfs_mount, snapshot['name']),
                      run_as_root=True)

    def _get_volume_location(self, volume_id):
        """Returns NFS mount address as <nfs_ip_address>:<nfs_mount_dir>.

        :param volume_id: string volume id
        """

        nfs_server_ip = self._get_host_ip(volume_id)
        export_path = self._get_export_path(volume_id)

        return nfs_server_ip + ':' + export_path

    def _get_provider_location(self, volume_id):
        """Returns provider location for given volume.

        :param volume_id: string volume id
        """

        volume = self.db.volume_get(self.context, volume_id)

        # same format as _get_volume_location
        return volume.provider_location

    def _get_host_ip(self, volume_id):
        """Returns IP address for the given volume.

        :param volume_id: string volume id
        """

        return self._get_provider_location(volume_id).split(':')[0]

    def _get_export_path(self, volume_id):
        """Returns NFS export path for the given volume.

        :param volume_id: string volume id
        """

        return self._get_provider_location(volume_id).split(':')[1]

    def _volume_not_present(self, nfs_mount, volume_name):
        """Check if volume exists.

        :param volume_name: string volume name
        """

        try:
            self._try_execute('ls', self._get_volume_path(nfs_mount,
                                                          volume_name))
        except processutils.ProcessExecutionError:
            # If the volume isn't present
            return True

        return False

    def _try_execute(self, *command, **kwargs):
        # NOTE(vish): Volume commands can partially fail due to timing, but
        #             running them a second time on failure will usually
        #             recover nicely.
        tries = 0
        while True:
            try:
                self._execute(*command, **kwargs)
                return True
            except processutils.ProcessExecutionError:
                tries += 1
                if tries >= self.configuration.num_shell_tries:
                    raise
                LOG.exception(_LE("Recovering from a failed execute.  "
                                  "Try number %s"), tries)
                time.sleep(tries ** 2)

    def _get_volume_path(self, nfs_share, volume_name):
        """Get volume path (local fs path) for given name on given nfs share.

        :param nfs_share string, example 172.18.194.100:/var/nfs
        :param volume_name string,
            example volume-91ee65ec-c473-4391-8c09-162b00c68a8c
        """

        return os.path.join(self._get_mount_point_for_share(nfs_share),
                            volume_name)

    def create_cloned_volume(self, volume, src_vref):
        """Creates a clone of the specified volume.

        :param volume: dictionary volume reference
        :param src_vref: dictionary src_vref reference
        """

        vol_size = volume['size']
        src_vol_size = src_vref['size']

        if vol_size < src_vol_size:
            msg = _("Cannot create clone of size %(vol_size)s from "
                    "volume of size %(src_vol_size)s")
            msg_fmt = {'vol_size': vol_size, 'src_vol_size': src_vol_size}
            raise exception.CinderException(msg % msg_fmt)

        self._clone_volume(src_vref['name'], volume['name'], src_vref['id'])

        if vol_size > src_vol_size:
            self.extend_volume(volume, vol_size)

        share = self._get_volume_location(src_vref['id'])

        return {'provider_location': share}

    def get_volume_stats(self, refresh=False):
        """Get volume stats.

        if 'refresh' is True, update the stats first.
        """

        _stats = super(HDSNFSDriver, self).get_volume_stats(refresh)
        _stats["vendor_name"] = 'HDS'
        _stats["driver_version"] = HDS_HNAS_NFS_VERSION
        _stats["storage_protocol"] = 'NFS'

        for pool in self.pools:
            capacity, free, used = self._get_capacity_info(pool['hdp'])
            pool['total_capacity_gb'] = capacity / float(units.Gi)
            pool['free_capacity_gb'] = free / float(units.Gi)
            pool['allocated_capacity_gb'] = used / float(units.Gi)
            pool['QoS_support'] = 'False'
            pool['reserved_percentage'] = 0

        _stats['pools'] = self.pools

        LOG.info(_LI('Driver stats: %s'), _stats)

        return _stats

    def _get_nfs_info(self):
        out = self.bend.get_nfs_info(self.config['hnas_cmd'],
                                     self.config['mgmt_ip0'],
                                     self.config['username'],
                                     self.config['password'])
        lines = out.split('\n')

        # dict based on NFS exports addresses
        conf = {}
        for line in lines:
            if 'Export' in line:
                inf = line.split()
                (export, path, fslabel, hdp, ip1) = \
                    inf[1], inf[3], inf[5], inf[7], inf[11]
                # 9, 10, etc are IP addrs
                key = ip1 + ':' + export
                conf[key] = {}
                conf[key]['path'] = path
                conf[key]['hdp'] = hdp
                conf[key]['fslabel'] = fslabel
                LOG.info(_LI("nfs_info: %(key)s: %(path)s, HDP: %(fslabel)s "
                             "FSID: %(hdp)s"),
                         {'key': key, 'path': path,
                          'fslabel': fslabel, 'hdp': hdp})

        return conf

    def do_setup(self, context):
        """Perform internal driver setup."""

        self.context = context
        self._load_shares_config(getattr(self.configuration,
                                         self.driver_prefix +
                                         '_shares_config'))
        LOG.info(_LI("Review shares: %s"), self.shares)

        nfs_info = self._get_nfs_info()

        LOG.debug("nfs_info: %s", nfs_info)

        for share in self.shares:
            if share in nfs_info.keys():
                LOG.info(_LI("share: %(share)s -> %(info)s"),
                         {'share': share, 'info': nfs_info[share]['path']})

                for svc in self.config['services'].keys():
                    if share == self.config['services'][svc]['hdp']:
                        self.config['services'][svc]['path'] = \
                            nfs_info[share]['path']
                        # don't overwrite HDP value
                        self.config['services'][svc]['fsid'] = \
                            nfs_info[share]['hdp']
                        self.config['services'][svc]['fslabel'] = \
                            nfs_info[share]['fslabel']
                        LOG.info(_LI("Save service info for"
                                     " %(svc)s -> %(hdp)s, %(path)s"),
                                 {'svc': svc, 'hdp': nfs_info[share]['hdp'],
                                  'path': nfs_info[share]['path']})
                        break
                if share != self.config['services'][svc]['hdp']:
                    LOG.error(_LE("NFS share %(share)s has no service entry:"
                                  " %(svc)s -> %(hdp)s"),
                              {'share': share, 'svc': svc,
                               'hdp': self.config['services'][svc]['hdp']})
                    raise exception.ParameterNotFound(param=svc)
            else:
                LOG.info(_LI("share: %s incorrect entry"), share)

        LOG.debug("self.config['services'] = %s", self.config['services'])

        service_list = self.config['services'].keys()
        for svc in service_list:
            svc = self.config['services'][svc]
            pool = {}
            pool['pool_name'] = svc['volume_type']
            pool['service_label'] = svc['volume_type']
            pool['hdp'] = svc['hdp']

            self.pools.append(pool)

        LOG.info(_LI("Configured pools: %s"), self.pools)

    def _clone_volume(self, volume_name, clone_name, volume_id):
        """Clones mounted volume using the HNAS file_clone.

        :param volume_name: string volume name
        :param clone_name: string clone name (or snapshot)
        :param volume_id: string volume id
        """

        export_path = self._get_export_path(volume_id)
        # volume-ID snapshot-ID, /cinder
        LOG.info(_LI("Cloning with volume_name %(vname)s clone_name %(cname)s"
                     " export_path %(epath)s"), {'vname': volume_name,
                                                 'cname': clone_name,
                                                 'epath': export_path})

        source_vol = self._id_to_vol(volume_id)
        # sps; added target
        (_hdp, _path, _fslabel) = self._get_service(source_vol)
        target_path = '%s/%s' % (_path, clone_name)
        source_path = '%s/%s' % (_path, volume_name)
        out = self.bend.file_clone(self.config['hnas_cmd'],
                                   self.config['mgmt_ip0'],
                                   self.config['username'],
                                   self.config['password'],
                                   _fslabel, source_path, target_path)

        return out

    def get_pool(self, volume):
        if not volume['volume_type']:
            return 'default'
        else:
            metadata = {}
            type_id = volume['volume_type_id']
            if type_id is not None:
                metadata = volume_types.get_volume_type_extra_specs(type_id)
            if not metadata.get('service_label'):
                return 'default'
            else:
                if metadata['service_label'] not in \
                        self.config['services'].keys():
                    return 'default'
                else:
                    return metadata['service_label']

    def create_volume(self, volume):
        """Creates a volume.

        :param volume: volume reference
        """
        self._ensure_shares_mounted()

        (_hdp, _path, _fslabel) = self._get_service(volume)

        volume['provider_location'] = _hdp

        LOG.info(_LI("Volume service: %(label)s. Casted to: %(loc)s"),
                 {'label': _fslabel, 'loc': volume['provider_location']})

        self._do_create_volume(volume)

        return {'provider_location': volume['provider_location']}

    def _convert_vol_ref_share_name_to_share_ip(self, vol_ref):
        """Converts the share point name to an IP address.

        The volume reference may have a DNS name portion in the share name.
        Convert that to an IP address and then restore the entire path.

        :param vol_ref:  driver-specific information used to identify a volume
        :returns:         a volume reference where share is in IP format
        """

        # First strip out share and convert to IP format.
        share_split = vol_ref.split(':')

        try:
            vol_ref_share_ip = cutils.resolve_hostname(share_split[0])
        except socket.gaierror as e:
            LOG.error(_LE('Invalid hostname %(host)s'),
                      {'host': share_split[0]})
            LOG.debug('error: %s', e.strerror)
            raise

        # Now place back into volume reference.
        vol_ref_share = vol_ref_share_ip + ':' + share_split[1]

        return vol_ref_share

    def _get_share_mount_and_vol_from_vol_ref(self, vol_ref):
        """Get the NFS share, the NFS mount, and the volume from reference.

        Determine the NFS share point, the NFS mount point, and the volume
        (with possible path) from the given volume reference. Raise exception
        if unsuccessful.

        :param vol_ref: driver-specific information used to identify a volume
        :returns:        NFS Share, NFS mount, volume path or raise error
        """
        # Check that the reference is valid.
        if 'source-name' not in vol_ref:
            reason = _('Reference must contain source-name element.')
            raise exception.ManageExistingInvalidReference(
                existing_ref=vol_ref, reason=reason)
        vol_ref_name = vol_ref['source-name']

        self._ensure_shares_mounted()

        # If a share was declared as '1.2.3.4:/a/b/c' in the nfs_shares_config
        # file, but the admin tries to manage the file located at
        # 'my.hostname.com:/a/b/c/d.vol', this might cause a lookup miss below
        # when searching self._mounted_shares to see if we have an existing
        # mount that would work to access the volume-to-be-managed (a string
        # comparison is done instead of IP comparison).
        vol_ref_share = self._convert_vol_ref_share_name_to_share_ip(
            vol_ref_name)
        for nfs_share in self._mounted_shares:
            cfg_share = self._convert_vol_ref_share_name_to_share_ip(nfs_share)
            (orig_share, work_share,
             file_path) = vol_ref_share.partition(cfg_share)
            if work_share == cfg_share:
                file_path = file_path[1:]  # strip off leading path divider
                LOG.debug("Found possible share %s; checking mount.",
                          work_share)
                nfs_mount = self._get_mount_point_for_share(nfs_share)
                vol_full_path = os.path.join(nfs_mount, file_path)
                if os.path.isfile(vol_full_path):
                    LOG.debug("Found share %(share)s and vol %(path)s on "
                              "mount %(mnt)s.",
                              {'share': nfs_share, 'path': file_path,
                               'mnt': nfs_mount})
                    return nfs_share, nfs_mount, file_path
            else:
                LOG.debug("vol_ref %(ref)s not on share %(share)s.",
                          {'ref': vol_ref_share, 'share': nfs_share})

        raise exception.ManageExistingInvalidReference(
            existing_ref=vol_ref,
            reason=_('Volume not found on configured storage backend.'))

    def manage_existing(self, volume, existing_vol_ref):
        """Manages an existing volume.

        The specified Cinder volume is to be taken into Cinder management.
        The driver will verify its existence and then rename it to the
        new Cinder volume name. It is expected that the existing volume
        reference is an NFS share point and some [/path]/volume;
        e.g., 10.10.32.1:/openstack/vol_to_manage
           or 10.10.32.1:/openstack/some_directory/vol_to_manage

        :param volume:           cinder volume to manage
        :param existing_vol_ref: driver-specific information used to identify a
                                 volume
        """

        # Attempt to find NFS share, NFS mount, and volume path from vol_ref.
        (nfs_share, nfs_mount, vol_path
         ) = self._get_share_mount_and_vol_from_vol_ref(existing_vol_ref)

        LOG.debug("Asked to manage NFS volume %(vol)s, with vol ref %(ref)s.",
                  {'vol': volume['id'],
                   'ref': existing_vol_ref['source-name']})
        self._check_pool_and_share(volume, nfs_share)
        if vol_path == volume['name']:
            LOG.debug("New Cinder volume %s name matches reference name: "
                      "no need to rename.", volume['name'])
        else:
            src_vol = os.path.join(nfs_mount, vol_path)
            dst_vol = os.path.join(nfs_mount, volume['name'])
            try:
                self._execute("mv", src_vol, dst_vol, run_as_root=False,
                              check_exit_code=True)
                LOG.debug("Setting newly managed Cinder volume name to %s.",
                          volume['name'])
                self._set_rw_permissions_for_all(dst_vol)
            except (OSError, processutils.ProcessExecutionError) as err:
                exception_msg = (_("Failed to manage existing volume "
                                   "%(name)s, because rename operation "
                                   "failed: Error msg: %(msg)s."),
                                 {'name': existing_vol_ref['source-name'],
                                  'msg': six.text_type(err)})
                raise exception.VolumeBackendAPIException(data=exception_msg)
        return {'provider_location': nfs_share}

    def _check_pool_and_share(self, volume, nfs_share):
        """Validates the pool and the NFS share.

        Checks if the NFS share for the volume-type chosen matches the
        one passed in the volume reference. Also, checks if the pool
        for the volume type matches the pool for the host passed.

        :param volume:    cinder volume reference
        :param nfs_share: NFS share passed to manage
        """
        pool_from_vol_type = self.get_pool(volume)

        pool_from_host = utils.extract_host(volume['host'], level='pool')

        if self.config['services'][pool_from_vol_type]['hdp'] != nfs_share:
            msg = (_("Failed to manage existing volume because the pool of "
                   "the volume type chosen does not match the NFS share "
                     "passed in the volume reference."),
                   {'Share passed': nfs_share,
                    'Share for volume type':
                    self.config['services'][pool_from_vol_type]['hdp']})
            raise exception.ManageExistingVolumeTypeMismatch(reason=msg)

        if pool_from_host != pool_from_vol_type:
            msg = (_("Failed to manage existing volume because the pool of "
                     "the volume type chosen does not match the pool of "
                     "the host."),
                   {'Pool of the volume type': pool_from_vol_type,
                   'Pool of the host': pool_from_host})
            raise exception.ManageExistingVolumeTypeMismatch(reason=msg)

    def manage_existing_get_size(self, volume, existing_vol_ref):
        """Returns the size of volume to be managed by manage_existing.

        When calculating the size, round up to the next GB.

        :param volume:           cinder volume to manage
        :param existing_vol_ref: existing volume to take under management
        """

        # Attempt to find NFS share, NFS mount, and volume path from vol_ref.
        (nfs_share, nfs_mount, vol_path
         ) = self._get_share_mount_and_vol_from_vol_ref(existing_vol_ref)

        try:
            LOG.debug("Asked to get size of NFS vol_ref %s.",
                      existing_vol_ref['source-name'])

            file_path = os.path.join(nfs_mount, vol_path)
            file_size = float(cutils.get_file_size(file_path)) / units.Gi
            vol_size = int(math.ceil(file_size))
        except (OSError, ValueError):
            exception_message = (_("Failed to manage existing volume "
                                   "%(name)s, because of error in getting "
                                   "volume size."),
                                 {'name': existing_vol_ref['source-name']})
            raise exception.VolumeBackendAPIException(data=exception_message)

        LOG.debug("Reporting size of NFS volume ref %(ref)s as %(size)d GB.",
                  {'ref': existing_vol_ref['source-name'], 'size': vol_size})

        return vol_size

    def unmanage(self, volume):
        """Removes the specified volume from Cinder management.

        It does not delete the underlying backend storage object. A log entry
        will be made to notify the Admin that the volume is no longer being
        managed.

        :param volume: cinder volume to unmanage
        """
        vol_str = CONF.volume_name_template % volume['id']
        path = self._get_mount_point_for_share(volume['provider_location'])

        new_str = "unmanage-" + vol_str

        vol_path = os.path.join(path, vol_str)
        new_path = os.path.join(path, new_str)

        try:
            self._execute("mv", vol_path, new_path,
                          run_as_root=False, check_exit_code=True)

            LOG.info(_LI("Cinder NFS volume with current path %(cr)s is "
                         "no longer being managed."), {'cr': new_path})

        except (OSError, ValueError):
            LOG.error(_LE("The NFS Volume %(cr)s does not exist."),
                      {'cr': new_path})