diff --git a/patches/cinder-vitastor.py b/patches/cinder-vitastor.py
index 49aebd08..87d5b830 100644
--- a/patches/cinder-vitastor.py
+++ b/patches/cinder-vitastor.py
@@ -1,3 +1,8 @@
+# Workaround:
+# 461: allow to create volume from snapshot
+# 527: adjust iodepth for faster deletion
+# 591: add failure case when creating a volume 
+
 # Vitastor Driver for OpenStack Cinder
 #
 # --------------------------------------------
diff --git a/vitastor.py b/vitastor.py
deleted file mode 100644
index 87d5b830..00000000
--- a/vitastor.py
+++ /dev/null
@@ -1,964 +0,0 @@
-# Workaround:
-# 461: allow to create volume from snapshot
-# 527: adjust iodepth for faster deletion
-# 591: add failure case when creating a volume 
-
-# Vitastor Driver for OpenStack Cinder
-#
-# --------------------------------------------
-# Install as cinder/volume/drivers/vitastor.py
-# --------------------------------------------
-#
-# Copyright 2020 Vitaliy Filippov
-#
-# 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.
-"""Cinder Vitastor Driver"""
-
-import binascii
-import base64
-import errno
-import json
-import math
-import os
-import tempfile
-
-from castellan import key_manager
-from oslo_config import cfg
-from oslo_log import log as logging
-from oslo_service import loopingcall
-from oslo_concurrency import processutils
-from oslo_utils import encodeutils
-from oslo_utils import excutils
-from oslo_utils import fileutils
-from oslo_utils import units
-import six
-from six.moves.urllib import request
-
-from cinder import exception
-from cinder.i18n import _
-from cinder.image import image_utils
-from cinder import interface
-from cinder import objects
-from cinder.objects import fields
-from cinder import utils
-from cinder.volume import configuration
-from cinder.volume import driver
-from cinder.volume import volume_utils
-
-VERSION = '0.6.10'
-
-LOG = logging.getLogger(__name__)
-
-VITASTOR_OPTS = [
-    cfg.StrOpt(
-        'vitastor_config_path',
-        default='/etc/vitastor/vitastor.conf',
-        help='Vitastor configuration file path'
-    ),
-    cfg.StrOpt(
-        'vitastor_etcd_address',
-        default='',
-        help='Vitastor etcd address(es)'),
-    cfg.StrOpt(
-        'vitastor_etcd_prefix',
-        default='/vitastor',
-        help='Vitastor etcd prefix'
-    ),
-    cfg.StrOpt(
-        'vitastor_pool_id',
-        default='',
-        help='Vitastor pool ID to use for volumes'
-    ),
-    # FIXME exclusive_cinder_pool ?
-]
-
-CONF = cfg.CONF
-CONF.register_opts(VITASTOR_OPTS, group = configuration.SHARED_CONF_GROUP)
-
-class VitastorDriverException(exception.VolumeDriverException):
-    message = _("Vitastor Cinder driver failure: %(reason)s")
-
-@interface.volumedriver
-class VitastorDriver(driver.CloneableImageVD,
-    driver.ManageableVD, driver.ManageableSnapshotsVD,
-    driver.BaseVD):
-    """Implements Vitastor volume commands."""
-
-    cfg = {}
-    _etcd_urls = []
-
-    def __init__(self, active_backend_id = None, *args, **kwargs):
-        super(VitastorDriver, self).__init__(*args, **kwargs)
-        self.configuration.append_config_values(VITASTOR_OPTS)
-
-    @classmethod
-    def get_driver_options(cls):
-        additional_opts = cls._get_oslo_driver_opts(
-            'reserved_percentage',
-            'max_over_subscription_ratio',
-            'volume_dd_blocksize'
-        )
-        return VITASTOR_OPTS + additional_opts
-
-    def do_setup(self, context):
-        """Performs initialization steps that could raise exceptions."""
-        super(VitastorDriver, self).do_setup(context)
-        # Make sure configuration is in UTF-8
-        for attr in [ 'config_path', 'etcd_address', 'etcd_prefix', 'pool_id' ]:
-            val = self.configuration.safe_get('vitastor_'+attr)
-            if val is not None:
-                self.cfg[attr] = utils.convert_str(val)
-        self.cfg = self._load_config(self.cfg)
-
-    def _load_config(self, cfg):
-        # Try to load configuration file
-        try:
-            f = open(cfg['config_path'] or '/etc/vitastor/vitastor.conf')
-            conf = json.loads(f.read())
-            f.close()
-            for k in conf:
-                cfg[k] = cfg.get(k, conf[k])
-        except:
-            pass
-        if isinstance(cfg['etcd_address'], str):
-            cfg['etcd_address'] = cfg['etcd_address'].split(',')
-        # Sanitize etcd URLs
-        for i, etcd_url in enumerate(cfg['etcd_address']):
-            ssl = False
-            if etcd_url.lower().startswith('http://'):
-                etcd_url = etcd_url[7:]
-            elif etcd_url.lower().startswith('https://'):
-                etcd_url = etcd_url[8:]
-                ssl = True
-            if etcd_url.find('/') < 0:
-                etcd_url += '/v3'
-            if ssl:
-                etcd_url = 'https://'+etcd_url
-            else:
-                etcd_url = 'http://'+etcd_url
-            cfg['etcd_address'][i] = etcd_url
-        return cfg
-
-    def check_for_setup_error(self):
-        """Returns an error if prerequisites aren't met."""
-
-    def _encode_etcd_key(self, key):
-        if not isinstance(key, bytes):
-            key = str(key).encode('utf-8')
-        return base64.b64encode(self.cfg['etcd_prefix'].encode('utf-8')+b'/'+key).decode('utf-8')
-
-    def _encode_etcd_value(self, value):
-        if not isinstance(value, bytes):
-            value = str(value).encode('utf-8')
-        return base64.b64encode(value).decode('utf-8')
-
-    def _encode_etcd_requests(self, obj):
-        for v in obj:
-            for rt in v:
-                if 'key' in v[rt]:
-                    v[rt]['key'] = self._encode_etcd_key(v[rt]['key'])
-                if 'range_end' in v[rt]:
-                    v[rt]['range_end'] = self._encode_etcd_key(v[rt]['range_end'])
-                if 'value' in v[rt]:
-                    v[rt]['value'] = self._encode_etcd_value(v[rt]['value'])
-
-    def _etcd_txn(self, params):
-        if 'compare' in params:
-            for v in params['compare']:
-                if 'key' in v:
-                    v['key'] = self._encode_etcd_key(v['key'])
-        if 'failure' in params:
-            self._encode_etcd_requests(params['failure'])
-        if 'success' in params:
-            self._encode_etcd_requests(params['success'])
-        body = json.dumps(params).encode('utf-8')
-        headers = {
-            'Content-Type': 'application/json'
-        }
-        err = None
-        for etcd_url in self.cfg['etcd_address']:
-            try:
-                resp = request.urlopen(request.Request(etcd_url+'/kv/txn', body, headers), timeout = 5)
-                data = json.loads(resp.read())
-                if 'responses' not in data:
-                    data['responses'] = []
-                for i, resp in enumerate(data['responses']):
-                    if 'response_range' in resp:
-                        if 'kvs' not in resp['response_range']:
-                            resp['response_range']['kvs'] = []
-                        for kv in resp['response_range']['kvs']:
-                            kv['key'] = base64.b64decode(kv['key'].encode('utf-8')).decode('utf-8')
-                            if kv['key'].startswith(self.cfg['etcd_prefix']+'/'):
-                                kv['key'] = kv['key'][len(self.cfg['etcd_prefix'])+1 : ]
-                            kv['value'] = json.loads(base64.b64decode(kv['value'].encode('utf-8')))
-                    if len(resp.keys()) != 1:
-                        LOG.exception('unknown responses['+str(i)+'] format: '+json.dumps(resp))
-                    else:
-                        resp = data['responses'][i] = resp[list(resp.keys())[0]]
-                return data
-            except Exception as e:
-                LOG.exception('error calling etcd transaction: '+body.decode('utf-8')+'\nerror: '+str(e))
-                err = e
-        raise err
-
-    def _etcd_foreach(self, prefix, add_fn):
-        total = 0
-        batch = 1000
-        begin = prefix+'/'
-        while True:
-            resp = self._etcd_txn({ 'success': [
-                { 'request_range': {
-                    'key': begin,
-                    'range_end': prefix+'0',
-                    'limit': batch+1,
-                } },
-            ] })
-            i = 0
-            while i < batch and i < len(resp['responses'][0]['kvs']):
-                kv = resp['responses'][0]['kvs'][i]
-                add_fn(kv)
-                i += 1
-            if len(resp['responses'][0]['kvs']) <= batch:
-                break
-            begin = resp['responses'][0]['kvs'][batch]['key']
-        return total
-
-    def _update_volume_stats(self):
-        location_info = json.dumps({
-            'config': self.configuration.vitastor_config_path,
-            'etcd_address': self.configuration.vitastor_etcd_address,
-            'etcd_prefix': self.configuration.vitastor_etcd_prefix,
-            'pool_id': self.configuration.vitastor_pool_id,
-        })
-
-        stats = {
-            'vendor_name': 'Vitastor',
-            'driver_version': self.VERSION,
-            'storage_protocol': 'vitastor',
-            'total_capacity_gb': 'unknown',
-            'free_capacity_gb': 'unknown',
-            # FIXME check if safe_get is required
-            'reserved_percentage': self.configuration.safe_get('reserved_percentage'),
-            'multiattach': True,
-            'thin_provisioning_support': True,
-            'max_over_subscription_ratio': self.configuration.safe_get('max_over_subscription_ratio'),
-            'location_info': location_info,
-            'backend_state': 'down',
-            'volume_backend_name': self.configuration.safe_get('volume_backend_name') or 'vitastor',
-            'replication_enabled': False,
-        }
-
-        try:
-            pool_stats = self._etcd_txn({ 'success': [
-                { 'request_range': { 'key': 'pool/stats/'+str(self.cfg['pool_id']) } }
-            ] })
-            total_provisioned = 0
-            def add_total(kv):
-                nonlocal total_provisioned
-                if kv['key'].find('@') >= 0:
-                    total_provisioned += kv['value']['size']
-            self._etcd_foreach('config/inode/'+str(self.cfg['pool_id']), lambda kv: add_total(kv))
-            stats['provisioned_capacity_gb'] = round(total_provisioned/1024.0/1024.0/1024.0, 2)
-            pool_stats = pool_stats['responses'][0]['kvs']
-            if len(pool_stats):
-                pool_stats = pool_stats[0]['value']
-                stats['free_capacity_gb'] = round(1024.0*(pool_stats['total_raw_tb']-pool_stats['used_raw_tb'])/pool_stats['raw_to_usable'], 2)
-                stats['total_capacity_gb'] = round(1024.0*pool_stats['total_raw_tb'], 2)
-            stats['backend_state'] = 'up'
-        except Exception as e:
-            # just log and return unknown capacities
-            LOG.exception('error getting vitastor pool stats: '+str(e))
-
-        self._stats = stats
-        
-    def get_volume_stats(self, refresh=False):
-        """Get volume stats.
-        If 'refresh' is True, run update the stats first.
-        """
-        if not self._stats or refresh:
-            self._update_volume_stats()
-
-        return self._stats
-
-    def _next_id(self, resp):
-        if len(resp['kvs']) == 0:
-            return (1, 0)
-        else:
-            return (1 + resp['kvs'][0]['value'], resp['kvs'][0]['mod_revision'])
-
-    def create_volume(self, volume):
-        """Creates a logical volume."""
-
-        size = int(volume.size) * units.Gi
-        # FIXME: Check if convert_str is really required
-        vol_name = utils.convert_str(volume.name)
-        if vol_name.find('@') >= 0 or vol_name.find('/') >= 0:
-            raise exception.VolumeBackendAPIException(data = '@ and / are forbidden in volume and snapshot names')
-
-        LOG.debug("creating volume '%s'", vol_name)
-
-        self._create_image(vol_name, { 'size': size })
-
-        if volume.encryption_key_id:
-            self._create_encrypted_volume(volume, volume.obj_context)
-
-        volume_update = {}
-        return volume_update
-
-    def _create_encrypted_volume(self, volume, context):
-        """Create a new LUKS encrypted image directly in Vitastor."""
-        vol_name = utils.convert_str(volume.name)
-        f, opts = self._encrypt_opts(volume, context)
-        # FIXME: Check if it works at all :-)
-        self._execute(
-            'qemu-img', 'convert', '-f', 'luks', *opts,
-            'vitastor:image='+vol_name.replace(':', '\\:')+self._qemu_args(),
-            '%sM' % (volume.size * 1024)
-        )
-        f.close()
-
-    def _encrypt_opts(self, volume, context):
-        encryption = volume_utils.check_encryption_provider(self.db, volume, context)
-        # Fetch the key associated with the volume and decode the passphrase
-        keymgr = key_manager.API(CONF)
-        key = keymgr.get(context, encryption['encryption_key_id'])
-        passphrase = binascii.hexlify(key.get_encoded()).decode('utf-8')
-        # Decode the dm-crypt style cipher spec into something qemu-img can use
-        cipher_spec = image_utils.decode_cipher(encryption['cipher'], encryption['key_size'])
-        tmp_dir = volume_utils.image_conversion_dir()
-        f = tempfile.NamedTemporaryFile(prefix = 'luks_', dir = tmp_dir)
-        f.write(passphrase)
-        f.flush()
-        return (f, [
-            '--object', 'secret,id=luks_sec,format=raw,file=%(passfile)s' % {'passfile': f.name},
-            '-o', 'key-secret=luks_sec,cipher-alg=%(cipher_alg)s,cipher-mode=%(cipher_mode)s,ivgen-alg=%(ivgen_alg)s' % cipher_spec,
-        ])
-
-    def create_snapshot(self, snapshot):
-        """Creates a volume snapshot."""
-
-        vol_name = utils.convert_str(snapshot.volume_name)
-        snap_name = utils.convert_str(snapshot.name)
-        if snap_name.find('@') >= 0 or snap_name.find('/') >= 0:
-            raise exception.VolumeBackendAPIException(data = '@ and / are forbidden in volume and snapshot names')
-        self._create_snapshot(vol_name, vol_name+'@'+snap_name)
-
-    def snapshot_revert_use_temp_snapshot(self):
-        """Disable the use of a temporary snapshot on revert."""
-        return False
-
-    def revert_to_snapshot(self, context, volume, snapshot):
-        """Revert a volume to a given snapshot."""
-
-        # FIXME Delete the image, then recreate it from the snapshot
-
-    def delete_snapshot(self, snapshot):
-        """Deletes a snapshot."""
-
-        vol_name = utils.convert_str(snapshot.volume_name)
-        snap_name = utils.convert_str(snapshot.name)
-
-        # Find the snapshot
-        resp = self._etcd_txn({ 'success': [
-            { 'request_range': { 'key': 'index/image/'+vol_name+'@'+snap_name } },
-        ] })
-        if len(resp['responses'][0]['kvs']) == 0:
-            raise exception.SnapshotNotFound(snapshot_id = snap_name)
-        inode_id = int(resp['responses'][0]['kvs'][0]['value']['id'])
-        pool_id = int(resp['responses'][0]['kvs'][0]['value']['pool_id'])
-        parents = {}
-        parents[(pool_id << 48) | (inode_id & 0xffffffffffff)] = True
-
-        # Check if there are child volumes
-        children = self._child_count(parents)
-        if children > 0:
-            raise exception.SnapshotIsBusy(snapshot_name = snap_name)
-
-        # FIXME: We can't delete snapshots because we can't merge layers yet
-        raise exception.VolumeBackendAPIException(data = 'Snapshot delete (layer merge) is not implemented yet')
-
-    def _child_count(self, parents):
-        children = 0
-        def add_child(kv):
-            nonlocal children
-            children += self._check_parent(kv, parents)
-        self._etcd_foreach('config/inode', lambda kv: add_child(kv))
-        return children
-
-    def _check_parent(self, kv, parents):
-        if 'parent_id' not in kv['value']:
-            return 0
-        parent_id = kv['value']['parent_id']
-        _, _, pool_id, inode_id = kv['key'].split('/')
-        parent_pool_id = pool_id
-        if 'parent_pool_id' in kv['value'] and kv['value']['parent_pool_id']:
-            parent_pool_id = kv['value']['parent_pool_id']
-        inode = (int(pool_id) << 48) | (int(inode_id) & 0xffffffffffff)
-        parent = (int(parent_pool_id) << 48) | (int(parent_id) & 0xffffffffffff)
-        if parent in parents and inode not in parents:
-            return 1
-        return 0
-
-    def create_cloned_volume(self, volume, src_vref):
-        """Create a cloned volume from another volume."""
-
-        size = int(volume.size) * units.Gi
-        src_name = utils.convert_str(src_vref.name)
-        dest_name = utils.convert_str(volume.name)
-        if dest_name.find('@') >= 0 or dest_name.find('/') >= 0:
-            raise exception.VolumeBackendAPIException(data = '@ and / are forbidden in volume and snapshot names')
-
-        # FIXME Do full copy if requested (cfg.disable_clone)
-
-        if src_vref.admin_metadata.get('readonly') == 'True':
-            # source volume is a volume-image cache entry or other readonly volume
-            # clone without intermediate snapshot
-            src = self._get_image(src_name)
-            LOG.debug("creating image '%s' from '%s'", dest_name, src_name)
-            new_cfg = self._create_image(dest_name, {
-                'size': size,
-                'parent_id': src['idx']['id'],
-                'parent_pool_id': src['idx']['pool_id'],
-            })
-            return {}
-
-        clone_snap = "%s@%s.clone_snap" % (src_name, dest_name)
-        make_img = True
-        if (volume.display_name and
-            volume.display_name.startswith('image-') and
-            src_vref.project_id != volume.project_id):
-            # idiotic openstack creates image-volume cache entries
-            # as clones of normal VM volumes... :-X prevent it :-D
-            clone_snap = dest_name
-            make_img = False
-
-        LOG.debug("creating layer '%s' under '%s'", clone_snap, src_name)
-        new_cfg = self._create_snapshot(src_name, clone_snap, True)
-        if make_img:
-            # Then create a clone from it
-            new_cfg = self._create_image(dest_name, {
-                'size': size,
-                'parent_id': new_cfg['parent_id'],
-                'parent_pool_id': new_cfg['parent_pool_id'],
-            })
-
-        return {}
-
-    def create_volume_from_snapshot(self, volume, snapshot):
-        """Creates a cloned volume from an existing snapshot."""
-
-        vol_name = utils.convert_str(volume.name)
-        snap_name = utils.convert_str(snapshot.name)
-
-        snap = self._get_image("volume-"+snapshot.volume_id+'@'+snap_name)
-        if not snap:
-            raise exception.SnapshotNotFound(snapshot_id = snap_name)
-        snap_inode_id = int(resp['responses'][0]['kvs'][0]['value']['id'])
-        snap_pool_id = int(resp['responses'][0]['kvs'][0]['value']['pool_id'])
-
-        size = snap['cfg']['size']
-        if int(volume.size):
-            size = int(volume.size) * units.Gi
-        new_cfg = self._create_image(vol_name, {
-            'size': size,
-            'parent_id': snap['idx']['id'],
-            'parent_pool_id': snap['idx']['pool_id'],
-        })
-
-        return {}
-
-    def _vitastor_args(self):
-        args = []
-        for k in [ 'config_path', 'etcd_address', 'etcd_prefix' ]:
-            v = self.configuration.safe_get('vitastor_'+k)
-            if v:
-                args.extend(['--'+k, v])
-        return args
-
-    def _qemu_args(self):
-        args = ''
-        for k in [ 'config_path', 'etcd_address', 'etcd_prefix' ]:
-            v = self.configuration.safe_get('vitastor_'+k)
-            kk = k
-            if kk == 'etcd_address':
-                # FIXME use etcd_address in qemu driver
-                kk = 'etcd_host'
-            if v:
-                args += ':'+kk.replace('_', '-')+'='+v.replace(':', '\\:')
-        return args
-
-    def delete_volume(self, volume):
-        """Deletes a logical volume."""
-
-        vol_name = utils.convert_str(volume.name)
-
-        # Find the volume and all its snapshots
-        range_end = b'index/image/' + vol_name.encode('utf-8')
-        range_end = range_end[0 : len(range_end)-1] + six.int2byte(range_end[len(range_end)-1] + 1)
-        resp = self._etcd_txn({ 'success': [
-            { 'request_range': { 'key': 'index/image/'+vol_name, 'range_end': range_end } },
-        ] })
-        if len(resp['responses'][0]['kvs']) == 0:
-            # already deleted
-            LOG.info("volume %s no longer exists in backend", vol_name)
-            return
-        layers = resp['responses'][0]['kvs']
-        layer_ids = {}
-        for kv in layers:
-            inode_id = int(kv['value']['id'])
-            pool_id = int(kv['value']['pool_id'])
-            inode_pool_id = (pool_id << 48) | (inode_id & 0xffffffffffff)
-            layer_ids[inode_pool_id] = True
-
-        # Check if the volume has clones and raise 'busy' if so
-        children = self._child_count(layer_ids)
-        if children > 0:
-            raise exception.VolumeIsBusy(volume_name = vol_name)
-
-        # Clear data
-        for kv in layers:
-            args = [
-                'vitastor-cli', 'rm-data', '--pool', str(kv['value']['pool_id']),
-                '--inode', str(kv['value']['id']), '--iodepth', '4', '--progress', '0',
-                *(self._vitastor_args())
-            ]
-            try:
-                self._execute(*args)
-            except processutils.ProcessExecutionError as exc:
-                LOG.error("Failed to remove layer "+kv['key']+": "+exc)
-                raise exception.VolumeBackendAPIException(data = exc.stderr)
-
-        # Delete all layers from etcd
-        requests = []
-        for kv in layers:
-            requests.append({ 'request_delete_range': { 'key': kv['key'] } })
-            requests.append({ 'request_delete_range': { 'key': 'config/inode/'+str(kv['value']['pool_id'])+'/'+str(kv['value']['id']) } })
-        self._etcd_txn({ 'success': requests })
-
-    def retype(self, context, volume, new_type, diff, host):
-        """Change extra type specifications for a volume."""
-
-        # FIXME Maybe (in the future) support multiple pools as different types
-        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 _create_image(self, vol_name, cfg):
-        pool_s = str(self.cfg['pool_id'])
-        image_id = 0
-        while image_id == 0:
-            # check if the image already exists and find a free ID
-            resp = self._etcd_txn({ 'success': [
-                { 'request_range': { 'key': 'index/image/'+vol_name } },
-                { 'request_range': { 'key': 'index/maxid/'+pool_s } },
-            ] })
-            if len(resp['responses'][0]['kvs']) > 0:
-                # already exists
-                raise exception.VolumeBackendAPIException(data = 'Volume '+vol_name+' already exists')
-            image_id, id_mod = self._next_id(resp['responses'][1])
-            # try to create the image
-            resp = self._etcd_txn({ 'compare': [
-                { 'target': 'MOD', 'mod_revision': id_mod, 'key': 'index/maxid/'+pool_s },
-                { 'target': 'VERSION', 'version': 0, 'key': 'index/image/'+vol_name },
-                { 'target': 'VERSION', 'version': 0, 'key': 'config/inode/'+pool_s+'/'+str(image_id) },
-            ], 'success': [
-                { 'request_put': { 'key': 'index/maxid/'+pool_s, 'value': image_id } },
-                { 'request_put': { 'key': 'index/image/'+vol_name, 'value': json.dumps({
-                    'id': image_id, 'pool_id': self.cfg['pool_id']
-                }) } },
-                { 'request_put': { 'key': 'config/inode/'+pool_s+'/'+str(image_id), 'value': json.dumps({
-                    **cfg, 'name': vol_name,
-                }) } },
-            ], 'failure': [
-                { 'request_put': { 'key': 'index/maxid/'+pool_s, 'value': image_id } },
-            ] })
-            if not resp.get('succeeded'):
-                # repeat
-                image_id = 0
-
-    def _create_snapshot(self, vol_name, snap_vol_name, allow_existing = False):
-        while True:
-            # check if the image already exists and snapshot doesn't
-            resp = self._etcd_txn({ 'success': [
-                { 'request_range': { 'key': 'index/image/'+vol_name } },
-                { 'request_range': { 'key': 'index/image/'+snap_vol_name } },
-            ] })
-            if len(resp['responses'][0]['kvs']) == 0:
-                raise exception.VolumeBackendAPIException(data = 'Volume '+vol_name+' does not exist')
-            if len(resp['responses'][1]['kvs']) > 0:
-                if allow_existing:
-                    snap_idx = resp['responses'][1]['kvs'][0]['value']
-                    resp = self._etcd_txn({ 'success': [
-                        { 'request_range': { 'key': 'config/inode/'+str(snap_idx['pool_id'])+'/'+str(snap_idx['id']) } },
-                    ] })
-                    if len(resp['responses'][0]['kvs']) == 0:
-                        raise exception.VolumeBackendAPIException(data =
-                            'Volume '+snap_vol_name+' is already indexed, but does not exist'
-                        )
-                    return resp['responses'][0]['kvs'][0]['value']
-                raise exception.VolumeBackendAPIException(
-                    data = 'Volume '+snap_vol_name+' already exists'
-                )
-            vol_idx = resp['responses'][0]['kvs'][0]['value']
-            vol_idx_mod = resp['responses'][0]['kvs'][0]['mod_revision']
-            # get image inode config and find a new ID
-            resp = self._etcd_txn({ 'success': [
-                { 'request_range': { 'key': 'config/inode/'+str(vol_idx['pool_id'])+'/'+str(vol_idx['id']) } },
-                { 'request_range': { 'key': 'index/maxid/'+str(self.cfg['pool_id']) } },
-            ] })
-            if len(resp['responses'][0]['kvs']) == 0:
-                raise exception.VolumeBackendAPIException(data = 'Volume '+vol_name+' does not exist')
-            vol_cfg = resp['responses'][0]['kvs'][0]['value']
-            vol_mod = resp['responses'][0]['kvs'][0]['mod_revision']
-            new_id, id_mod = self._next_id(resp['responses'][1])
-            # try to redirect image to the new inode
-            new_cfg = {
-                **vol_cfg, 'name': vol_name, 'parent_id': vol_idx['id'], 'parent_pool_id': vol_idx['pool_id']
-            }
-            resp = self._etcd_txn({ 'compare': [
-                { 'target': 'MOD', 'mod_revision': vol_idx_mod, 'key': 'index/image/'+vol_name },
-                { 'target': 'MOD', 'mod_revision': vol_mod, 'key': 'config/inode/'+str(vol_idx['pool_id'])+'/'+str(vol_idx['id']) },
-                { 'target': 'MOD', 'mod_revision': id_mod, 'key': 'index/maxid/'+str(self.cfg['pool_id']) },
-                { 'target': 'VERSION', 'version': 0, 'key': 'index/image/'+snap_vol_name },
-                { 'target': 'VERSION', 'version': 0, 'key': 'config/inode/'+str(self.cfg['pool_id'])+'/'+str(new_id) },
-            ], 'success': [
-                { 'request_put': { 'key': 'index/maxid/'+str(self.cfg['pool_id']), 'value': new_id } },
-                { 'request_put': { 'key': 'index/image/'+vol_name, 'value': json.dumps({
-                    'id': new_id, 'pool_id': self.cfg['pool_id']
-                }) } },
-                { 'request_put': { 'key': 'config/inode/'+str(self.cfg['pool_id'])+'/'+str(new_id), 'value': json.dumps(new_cfg) } },
-                { 'request_put': { 'key': 'index/image/'+snap_vol_name, 'value': json.dumps({
-                    'id': vol_idx['id'], 'pool_id': vol_idx['pool_id']
-                }) } },
-                { 'request_put': { 'key': 'config/inode/'+str(vol_idx['pool_id'])+'/'+str(vol_idx['id']), 'value': json.dumps({
-                    **vol_cfg, 'name': snap_vol_name, 'readonly': True
-                }) } }
-            ] })
-            if resp.get('succeeded'):
-                return new_cfg
-
-    def initialize_connection(self, volume, connector):
-        data = {
-            'driver_volume_type': 'vitastor',
-            'data': {
-                'config_path': self.configuration.vitastor_config_path,
-                'etcd_address': self.configuration.vitastor_etcd_address,
-                'etcd_prefix': self.configuration.vitastor_etcd_prefix,
-                'name': volume.name,
-                'logical_block_size': '512',
-                'physical_block_size': '4096',
-            }
-        }
-        LOG.debug('connection data: %s', data)
-        return data
-
-    def terminate_connection(self, volume, connector, **kwargs):
-        pass
-
-    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 url_location.startswith('cinder://'):
-                    # The idea is to use cinder://<volume-id> Glance volumes as base images
-                    base_vol = self.db.volume_get(context, url_location[len('cinder://') : ])
-                    if not base_vol or base_vol.volume_type_id != volume.volume_type_id:
-                        continue
-                    size = int(volume.size) * units.Gi
-                    dest_name = utils.convert_str(volume.name)
-                    # Find or create the base snapshot
-                    snap_cfg = self._create_snapshot(base_vol.name, base_vol.name+'@.clone_snap', True)
-                    # Then create a clone from it
-                    new_cfg = self._create_image(dest_name, {
-                        'size': size,
-                        'parent_id': snap_cfg['parent_id'],
-                        'parent_pool_id': snap_cfg['parent_pool_id'],
-                    })
-                    return ({}, True)
-        return ({}, False)
-
-    def copy_image_to_encrypted_volume(self, context, volume, image_service, image_id):
-        self.copy_image_to_volume(context, volume, image_service, image_id, encrypted = True)
-
-    def copy_image_to_volume(self, context, volume, image_service, image_id, encrypted = False):
-        tmp_dir = volume_utils.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
-            )
-            out_format = [ '-O', 'raw' ]
-            if encrypted:
-                key_file, opts = self._encrypt_opts(volume, context)
-                out_format = [ '-O', 'luks', *opts ]
-            dest_name = utils.convert_str(volume.name)
-            self._try_execute(
-                'qemu-img', 'convert', '-f', 'raw', tmp.name, *out_format,
-                'vitastor:image='+dest_name.replace(':', '\\:')+self._qemu_args()
-            )
-            if encrypted:
-                key_file.close()
-
-    def copy_volume_to_image(self, context, volume, image_service, image_meta):
-        tmp_dir = volume_utils.image_conversion_dir()
-        tmp_file = os.path.join(tmp_dir, volume.name + '-' + image_meta['id'])
-        with fileutils.remove_path_on_error(tmp_file):
-            vol_name = utils.convert_str(volume.name)
-            self._try_execute(
-                'qemu-img', 'convert', '-f', 'raw',
-                'vitastor:image='+vol_name.replace(':', '\\:')+self._qemu_args(),
-                '-O', 'raw', tmp_file
-            )
-            # FIXME: Copy directly if the destination image is also in Vitastor
-            volume_utils.upload_volume(context, image_service, image_meta, tmp_file, volume)
-        os.unlink(tmp_file)
-
-    def _get_image(self, vol_name):
-        # find the image
-        resp = self._etcd_txn({ 'success': [
-            { 'request_range': { 'key': 'index/image/'+vol_name } },
-        ] })
-        if len(resp['responses'][0]['kvs']) == 0:
-            return None
-        vol_idx = resp['responses'][0]['kvs'][0]['value']
-        vol_idx_mod = resp['responses'][0]['kvs'][0]['mod_revision']
-        # get image inode config
-        resp = self._etcd_txn({ 'success': [
-            { 'request_range': { 'key': 'config/inode/'+str(vol_idx['pool_id'])+'/'+str(vol_idx['id']) } },
-        ] })
-        if len(resp['responses'][0]['kvs']) == 0:
-            return None
-        vol_cfg = resp['responses'][0]['kvs'][0]['value']
-        vol_cfg_mod = resp['responses'][0]['kvs'][0]['mod_revision']
-        return {
-            'cfg': vol_cfg,
-            'cfg_mod': vol_cfg_mod,
-            'idx': vol_idx,
-            'idx_mod': vol_idx_mod,
-        }
-
-    def extend_volume(self, volume, new_size):
-        """Extend an existing volume."""
-        vol_name = utils.convert_str(volume.name)
-        while True:
-            vol = self._get_image(vol_name)
-            if not vol:
-                raise exception.VolumeBackendAPIException(data = 'Volume '+vol_name+' does not exist')
-            # change size
-            size = int(new_size) * units.Gi
-            if size == vol['cfg']['size']:
-                break
-            resp = self._etcd_txn({ 'compare': [ {
-                'target': 'MOD',
-                'mod_revision': vol['cfg_mod'],
-                'key': 'config/inode/'+str(vol['idx']['pool_id'])+'/'+str(vol['idx']['id']),
-            } ], 'success': [
-                { 'request_put': {
-                    'key': 'config/inode/'+str(vol['idx']['pool_id'])+'/'+str(vol['idx']['id']),
-                    'value': json.dumps({ **vol['cfg'], 'size': size }),
-                } },
-            ] })
-            if resp.get('succeeded'):
-                break
-        LOG.debug(
-            "Extend volume from %(old_size)s GB to %(new_size)s GB.",
-            {'old_size': volume.size, 'new_size': new_size}
-        )
-
-    def _add_manageable_volume(self, kv, manageable_volumes, cinder_ids):
-        cfg = kv['value']
-        if kv['key'].find('@') >= 0:
-            # snapshot
-            return
-        image_id = volume_utils.extract_id_from_volume_name(cfg['name'])
-        image_info = {
-            'reference': {'source-name': image_name},
-            'size': int(math.ceil(float(cfg['size']) / units.Gi)),
-            'cinder_id': None,
-            'extra_info': None,
-        }
-        if image_id in cinder_ids:
-            image_info['cinder_id'] = image_id
-            image_info['safe_to_manage'] = False
-            image_info['reason_not_safe'] = 'already managed'
-        else:
-            image_info['safe_to_manage'] = True
-            image_info['reason_not_safe'] = None
-        manageable_volumes.append(image_info)
-
-    def get_manageable_volumes(self, cinder_volumes, marker, limit, offset, sort_keys, sort_dirs):
-        manageable_volumes = []
-        cinder_ids = [resource['id'] for resource in cinder_volumes]
-
-        # List all volumes
-        # FIXME: It's possible to use pagination in our case, but.. do we want it?
-        self._etcd_foreach('config/inode/'+str(self.cfg['pool_id']),
-            lambda kv: self._add_manageable_volume(kv, manageable_volumes, cinder_ids))
-
-        return volume_utils.paginate_entries_list(
-            manageable_volumes, marker, limit, offset, sort_keys, sort_dirs)
-
-    def _get_existing_name(existing_ref):
-        if not isinstance(existing_ref, dict):
-            existing_ref = {"source-name": existing_ref}
-        if 'source-name' not in existing_ref:
-            reason = _('Reference must contain source-name element.')
-            raise exception.ManageExistingInvalidReference(existing_ref=existing_ref, reason=reason)
-        src_name = utils.convert_str(existing_ref['source-name'])
-        if not src_name:
-            reason = _('Reference must contain source-name element.')
-            raise exception.ManageExistingInvalidReference(existing_ref=existing_ref, reason=reason)
-        return src_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: {'source-name': <image name>}
-        """
-        src_name = self._get_existing_name(existing_ref)
-        vol = self._get_image(src_name)
-        if not vol:
-            raise exception.VolumeBackendAPIException(data = 'Volume '+src_name+' does not exist')
-        return int(math.ceil(float(vol['cfg']['size']) / units.Gi))
-
-    def manage_existing(self, volume, existing_ref):
-        """Manages an existing image.
-
-        Renames the image name to match the expected name for the volume.
-
-        :param volume: volume ref info to be set
-        :param existing_ref: {'source-name': <image name>}
-        """
-        from_name = self._get_existing_name(existing_ref)
-        to_name = utils.convert_str(volume.name)
-        self._rename(from_name, to_name)
-
-    def _rename(self, from_name, to_name):
-        while True:
-            vol = self._get_image(from_name)
-            if not vol:
-                raise exception.VolumeBackendAPIException(data = 'Volume '+from_name+' does not exist')
-            to = self._get_image(to_name)
-            if to:
-                raise exception.VolumeBackendAPIException(data = 'Volume '+to_name+' already exists')
-            resp = self._etcd_txn({ 'compare': [
-                { 'target': 'MOD', 'mod_revision': vol['idx_mod'], 'key': 'index/image/'+vol['cfg']['name'] },
-                { 'target': 'MOD', 'mod_revision': vol['cfg_mod'], 'key': 'config/inode/'+str(vol['idx']['pool_id'])+'/'+str(vol['idx']['id']) },
-                { 'target': 'VERSION', 'version': 0, 'key': 'index/image/'+to_name },
-            ], 'success': [
-                { 'request_delete_range': { 'key': 'index/image/'+vol['cfg']['name'] } },
-                { 'request_put': { 'key': 'index/image/'+to_name, 'value': json.dumps(vol['idx']) } },
-                { 'request_put': { 'key': 'config/inode/'+str(vol['idx']['pool_id'])+'/'+str(vol['idx']['id']),
-                    'value': json.dumps({ **vol['cfg'], 'name': to_name }) } },
-            ] })
-            if resp.get('succeeded'):
-                break
-
-    def unmanage(self, volume):
-        pass
-
-    def _add_manageable_snapshot(self, kv, manageable_snapshots, cinder_ids):
-        cfg = kv['value']
-        dog = kv['key'].find('@')
-        if dog < 0:
-            # snapshot
-            return
-        image_name = kv['key'][0 : dog]
-        snap_name = kv['key'][dog+1 : ]
-        snapshot_id = volume_utils.extract_id_from_snapshot_name(snap_name)
-        snapshot_info = {
-            'reference': {'source-name': snap_name},
-            'size': int(math.ceil(float(cfg['size']) / units.Gi)),
-            'cinder_id': None,
-            'extra_info': None,
-            'safe_to_manage': False,
-            'reason_not_safe': None,
-            'source_reference': {'source-name': image_name}
-        }
-        if snapshot_id in cinder_ids:
-            # Exclude snapshots already managed.
-            snapshot_info['reason_not_safe'] = ('already managed')
-            snapshot_info['cinder_id'] = snapshot_id
-        elif snap_name.endswith('.clone_snap'):
-            # Exclude clone snapshot.
-            snapshot_info['reason_not_safe'] = ('used for clone snap')
-        else:
-            snapshot_info['safe_to_manage'] = True
-        manageable_snapshots.append(snapshot_info)
-
-    def get_manageable_snapshots(self, cinder_snapshots, marker, limit, offset, sort_keys, sort_dirs):
-        """List manageable snapshots in Vitastor."""
-        manageable_snapshots = []
-        cinder_snapshot_ids = [resource['id'] for resource in cinder_snapshots]
-        # List all volumes
-        # FIXME: It's possible to use pagination in our case, but.. do we want it?
-        self._etcd_foreach('config/inode/'+str(self.cfg['pool_id']),
-            lambda kv: self._add_manageable_volume(kv, manageable_snapshots, cinder_snapshot_ids))
-        return volume_utils.paginate_entries_list(
-            manageable_snapshots, marker, limit, offset, sort_keys, sort_dirs)
-
-    def manage_existing_snapshot_get_size(self, snapshot, existing_ref):
-        """Return size of an existing image for manage_existing.
-
-        :param snapshot: snapshot ref info to be set
-        :param existing_ref: {'source-name': <name of snapshot>}
-        """
-        vol_name = utils.convert_str(snapshot.volume_name)
-        snap_name = self._get_existing_name(existing_ref)
-        vol = self._get_image(vol_name+'@'+snap_name)
-        if not vol:
-            raise exception.ManageExistingInvalidReference(
-                existing_ref=snapshot_name, reason='Specified snapshot does not exist.'
-            )
-        return int(math.ceil(float(vol['cfg']['size']) / units.Gi))
-
-    def manage_existing_snapshot(self, snapshot, existing_ref):
-        """Manages an existing snapshot.
-
-        Renames the snapshot name to match the expected name for the snapshot.
-        Error checking done by manage_existing_get_size is not repeated.
-
-        :param snapshot: snapshot ref info to be set
-        :param existing_ref: {'source-name': <name of snapshot>}
-        """
-        vol_name = utils.convert_str(snapshot.volume_name)
-        snap_name = self._get_existing_name(existing_ref)
-        from_name = vol_name+'@'+snap_name
-        to_name = vol_name+'@'+utils.convert_str(snapshot.name)
-        self._rename(from_name, to_name)
-
-    def unmanage_snapshot(self, snapshot):
-        """Removes the specified snapshot from Cinder management."""
-        pass
-
-    def _dumps(self, obj):
-        return json.dumps(obj, separators=(',', ':'), sort_keys=True)