# # The Qubes OS Project, http://www.qubes-os.org # # Copyright (C) 2016 Bahtiar `kalkin-` Gadimov # # This library is free software; you can redistribute it and/or # modify it under the terms of the GNU Lesser General Public # License as published by the Free Software Foundation; either # version 2.1 of the License, or (at your option) any later version. # # This library is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU # Lesser General Public License for more details. # # You should have received a copy of the GNU Lesser General Public # License along with this library; if not, see . # ''' Driver for storing vm images in a LVM thin pool ''' import functools import logging import os import subprocess import time import asyncio import qubes import qubes.storage import qubes.utils def check_lvm_version(): #Check if lvm is very very old, like in Travis-CI try: lvm_help = subprocess.check_output(['lvm', 'lvcreate', '--help'], stderr=subprocess.DEVNULL).decode() return '--setactivationskip' not in lvm_help except (subprocess.CalledProcessError, FileNotFoundError): pass lvm_is_very_old = check_lvm_version() class ThinPool(qubes.storage.Pool): ''' LVM Thin based pool implementation Volumes are stored as LVM thin volumes, in thin pool specified by *volume_group*/*thin_pool* arguments. LVM volume naming scheme: vm-{vm_name}-{volume_name}[-suffix] Where suffix can be one of: "-snap" - snapshot for currently running VM, at VM shutdown will be either discarded (if save_on_stop=False), or committed (if save_on_stop=True) "-{revision_id}" - volume revision - new revision is automatically created at each VM shutdown, *revisions_to_keep* control how many old revisions (in addition to the current one) should be stored "" (no suffix) - the most recent committed volume state; also volatile volume (snap_on_start=False, save_on_stop=False) On VM startup, new volume is created, depending on volume type, according to the table below: snap_on_start, save_on_stop False, False, - no suffix, fresh empty volume False, True, - "-snap", snapshot of last committed revision True , False, - "-snap", snapshot of last committed revision of source volume (from VM's template) True, True, - unsupported configuration Volume's revision_id format is "{timestamp}-back", where timestamp is in '%s' format (seconds since unix epoch) ''' # pylint: disable=protected-access size_cache = None driver = 'lvm_thin' def __init__(self, *, name, revisions_to_keep=1, volume_group, thin_pool): super().__init__(name=name, revisions_to_keep=revisions_to_keep) self.volume_group = volume_group self.thin_pool = thin_pool self._pool_id = "{!s}/{!s}".format(volume_group, thin_pool) self.log = logging.getLogger('qubes.storage.lvm.%s' % self._pool_id) self._volume_objects_cache = {} def __repr__(self): return '<{} at {:#x} name={!r} volume_group={!r} thin_pool={!r}>'.\ format( type(self).__name__, id(self), self.name, self.volume_group, self.thin_pool) @property def config(self): return { 'name': self.name, 'volume_group': self.volume_group, 'thin_pool': self.thin_pool, 'driver': ThinPool.driver, 'revisions_to_keep': self.revisions_to_keep, } def destroy(self): pass # TODO Should we remove an existing pool? def init_volume(self, vm, volume_config): ''' Initialize a :py:class:`qubes.storage.Volume` from `volume_config`. ''' if 'revisions_to_keep' not in volume_config.keys(): volume_config['revisions_to_keep'] = self.revisions_to_keep if 'vid' not in volume_config.keys(): if vm and hasattr(vm, 'name'): vm_name = vm.name else: # for the future if we have volumes not belonging to a vm vm_name = qubes.utils.random_string() assert self.name volume_config['vid'] = "{!s}/vm-{!s}-{!s}".format( self.volume_group, vm_name, volume_config['name']) volume_config['volume_group'] = self.volume_group volume_config['pool'] = self volume = ThinVolume(**volume_config) self._volume_objects_cache[volume_config['vid']] = volume return volume def setup(self): reset_cache() cache_key = self.volume_group + '/' + self.thin_pool if cache_key not in size_cache: raise qubes.storage.StoragePoolException( 'Thin pool {} does not exist'.format(cache_key)) if size_cache[cache_key]['attr'][0] != 't': raise qubes.storage.StoragePoolException( 'Volume {} is not a thin pool'.format(cache_key)) # TODO Should we create a non existing pool? def get_volume(self, vid): ''' Return a volume with given vid''' if vid in self._volume_objects_cache: return self._volume_objects_cache[vid] config = { 'pool': self, 'vid': vid, 'name': vid, 'volume_group': self.volume_group, } # don't cache this object, as it doesn't carry full configuration return ThinVolume(**config) def list_volumes(self): ''' Return a list of volumes managed by this pool ''' volumes = [] for vid, vol_info in size_cache.items(): if not vid.startswith(self.volume_group + '/'): continue if vol_info['pool_lv'] != self.thin_pool: continue if vid.endswith('-snap') or vid.endswith('-import'): # implementation detail volume continue if vid.endswith('-back'): # old revisions continue volume = self.get_volume(vid) if volume in volumes: continue volumes.append(volume) return volumes @property def size(self): try: return qubes.storage.lvm.size_cache[ self.volume_group + '/' + self.thin_pool]['size'] except KeyError: return 0 @property def usage(self): refresh_cache() try: return qubes.storage.lvm.size_cache[ self.volume_group + '/' + self.thin_pool]['usage'] except KeyError: return 0 @property def usage_details(self): result = {} result['data_size'] = self.size result['data_usage'] = self.usage try: metadata_size = qubes.storage.lvm.size_cache[ self.volume_group + '/' + self.thin_pool]['metadata_size'] metadata_usage = qubes.storage.lvm.size_cache[ self.volume_group + '/' + self.thin_pool]['metadata_usage'] except KeyError: metadata_size = 0 metadata_usage = 0 result['metadata_size'] = metadata_size result['metadata_usage'] = metadata_usage return result _init_cache_cmd = ['lvs', '--noheadings', '-o', 'vg_name,pool_lv,name,lv_size,data_percent,lv_attr,origin,lv_metadata_size,' 'metadata_percent', '--units', 'b', '--separator', ';'] def _parse_lvm_cache(lvm_output): result = {} for line in lvm_output.splitlines(): line = line.decode().strip() pool_name, pool_lv, name, size, usage_percent, attr, \ origin, metadata_size, metadata_percent = line.split(';', 8) if '' in [pool_name, name, size, usage_percent]: continue name = pool_name + "/" + name size = int(size[:-1]) # Remove 'B' suffix usage = int(size / 100 * float(usage_percent)) if metadata_size: metadata_size = int(metadata_size[:-1]) metadata_usage = int(metadata_size / 100 * float(metadata_percent)) else: metadata_usage = None result[name] = {'size': size, 'usage': usage, 'pool_lv': pool_lv, 'attr': attr, 'origin': origin, 'metadata_size': metadata_size, 'metadata_usage': metadata_usage} return result def init_cache(log=logging.getLogger('qubes.storage.lvm')): cmd = _init_cache_cmd if os.getuid() != 0: cmd = ['sudo'] + cmd environ = os.environ.copy() environ['LC_ALL'] = 'C.utf8' p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, close_fds=True, env=environ) out, err = p.communicate() return_code = p.returncode if return_code == 0 and err: log.warning(err) elif return_code != 0: raise qubes.storage.StoragePoolException(err) return _parse_lvm_cache(out) @asyncio.coroutine def init_cache_coro(log=logging.getLogger('qubes.storage.lvm')): cmd = _init_cache_cmd if os.getuid() != 0: cmd = ['sudo'] + cmd environ = os.environ.copy() environ['LC_ALL'] = 'C.utf8' p = yield from asyncio.create_subprocess_exec(*cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, close_fds=True, env=environ) out, err = yield from p.communicate() return_code = p.returncode if return_code == 0 and err: log.warning(err) elif return_code != 0: raise qubes.storage.StoragePoolException(err) return _parse_lvm_cache(out) size_cache_time = 0 size_cache = init_cache() def _revision_sort_key(revision): '''Sort key for revisions. Sort them by time :returns timestamp ''' if isinstance(revision, tuple): revision = revision[0] if '-' in revision: revision = revision.split('-')[0] return int(revision) def locked(method): '''Decorator running given Volume's coroutine under a lock. Needs to be added after wrapping with @asyncio.coroutine, for example: >>>@locked >>>@asyncio.coroutine >>>def start(self): >>> pass ''' @asyncio.coroutine @functools.wraps(method) def wrapper(self, *args, **kwargs): with (yield from self._lock): # pylint: disable=protected-access return (yield from method(self, *args, **kwargs)) return wrapper class ThinVolume(qubes.storage.Volume): ''' Default LVM thin volume implementation ''' # pylint: disable=too-few-public-methods def __init__(self, volume_group, **kwargs): self.volume_group = volume_group super().__init__(**kwargs) self.log = logging.getLogger('qubes.storage.lvm.%s' % str(self.pool)) if self.snap_on_start or self.save_on_stop: self._vid_snap = self.vid + '-snap' if self.save_on_stop: self._vid_import = self.vid + '-import' self._lock = asyncio.Lock() @property def path(self): return '/dev/' + self._vid_current @property def _vid_current(self): if self.vid in size_cache: return self.vid vol_revisions = self.revisions if vol_revisions: last_revision = \ max(vol_revisions.items(), key=_revision_sort_key)[0] return self.vid + '-' + last_revision # detached pool? return expected path return self.vid @property def revisions(self): name_prefix = self.vid + '-' revisions = {} for revision_vid in size_cache: if not revision_vid.startswith(name_prefix): continue if not revision_vid.endswith('-back'): continue revision_vid = revision_vid[len(name_prefix):] if revision_vid.count('-') > 1: # VM+volume name is a prefix of another VM, see #4680 continue # get revision without suffix seconds = int(revision_vid.split('-')[0]) iso_date = qubes.storage.isodate(seconds).split('.', 1)[0] revisions[revision_vid] = iso_date return revisions @property def size(self): try: if self.is_dirty(): return qubes.storage.lvm.size_cache[self._vid_snap]['size'] return qubes.storage.lvm.size_cache[self._vid_current]['size'] except KeyError: return self._size @size.setter def size(self, _): raise qubes.storage.StoragePoolException( "You shouldn't use lvm size setter") @asyncio.coroutine def _reset(self): ''' Resets a volatile volume ''' assert not self.snap_on_start and not self.save_on_stop, \ "Not a volatile volume" self.log.debug('Resetting volatile %s', self.vid) try: cmd = ['remove', self.vid] yield from qubes_lvm_coro(cmd, self.log) except qubes.storage.StoragePoolException: pass # pylint: disable=protected-access cmd = ['create', self.pool._pool_id, self.vid.split('/')[1], str(self.size)] yield from qubes_lvm_coro(cmd, self.log) @asyncio.coroutine def _remove_revisions(self, revisions=None): '''Remove old volume revisions. If no revisions list is given, it removes old revisions according to :py:attr:`revisions_to_keep` :param revisions: list of revisions to remove ''' if revisions is None: revisions = sorted(self.revisions.items(), key=_revision_sort_key) # pylint: disable=invalid-unary-operand-type revisions = revisions[:(-self.revisions_to_keep) or None] revisions = [rev_id for rev_id, _ in revisions] for rev_id in revisions: # safety check assert rev_id != self._vid_current try: cmd = ['remove', self.vid + '-' + rev_id] yield from qubes_lvm_coro(cmd, self.log) except qubes.storage.StoragePoolException: pass @asyncio.coroutine def _commit(self, vid_to_commit=None, keep=False): ''' Commit temporary volume into current one. By default :py:attr:`_vid_snap` is used (which is created by :py:meth:`start()`), but can be overriden by *vid_to_commit* argument. :param vid_to_commit: LVM volume ID to commit into this one :param keep: whether to keep or not *vid_to_commit*. IOW use 'clone' or 'rename' methods. :return: None ''' msg = "Trying to commit {!s}, but it has save_on_stop == False" msg = msg.format(self) assert self.save_on_stop, msg msg = "Trying to commit {!s}, but it has rw == False" msg = msg.format(self) assert self.rw, msg if vid_to_commit is None: assert hasattr(self, '_vid_snap') vid_to_commit = self._vid_snap assert self._lock.locked() if not os.path.exists('/dev/' + vid_to_commit): # nothing to commit return if self._vid_current == self.vid: cmd = ['rename', self.vid, '{}-{}-back'.format(self.vid, int(time.time()))] yield from qubes_lvm_coro(cmd, self.log) yield from reset_cache_coro() cmd = ['clone' if keep else 'rename', vid_to_commit, self.vid] yield from qubes_lvm_coro(cmd, self.log) yield from reset_cache_coro() # make sure the one we've committed right now is properly # detected as the current one - before removing anything assert self._vid_current == self.vid # and remove old snapshots, if needed yield from self._remove_revisions() @locked @asyncio.coroutine def create(self): assert self.vid assert self.size if self.save_on_stop: if self.source: cmd = ['clone', self.source.path, self.vid] else: cmd = [ 'create', self.pool._pool_id, # pylint: disable=protected-access self.vid.split('/', 1)[1], str(self.size) ] yield from qubes_lvm_coro(cmd, self.log) yield from reset_cache_coro() return self @locked @asyncio.coroutine def remove(self): assert self.vid try: if os.path.exists('/dev/' + self._vid_snap): cmd = ['remove', self._vid_snap] yield from qubes_lvm_coro(cmd, self.log) except AttributeError: pass try: if os.path.exists('/dev/' + self._vid_import): cmd = ['remove', self._vid_import] yield from qubes_lvm_coro(cmd, self.log) except AttributeError: pass yield from self._remove_revisions(self.revisions.keys()) if not os.path.exists(self.path): return cmd = ['remove', self.path] yield from qubes_lvm_coro(cmd, self.log) yield from reset_cache_coro() # pylint: disable=protected-access self.pool._volume_objects_cache.pop(self.vid, None) def export(self): ''' Returns an object that can be `open()`. ''' # make sure the device node is available qubes_lvm(['activate', self.path], self.log) devpath = self.path return devpath @locked @asyncio.coroutine def import_volume(self, src_volume): if not src_volume.save_on_stop: return self if self.is_dirty(): raise qubes.storage.StoragePoolException( 'Cannot import to dirty volume {} -' ' start and stop a qube to cleanup'.format(self.vid)) self.abort_if_import_in_progress() # HACK: neat trick to speed up testing if you have same physical thin # pool assigned to two qubes-pools i.e: qubes_dom0 and test-lvm # pylint: disable=line-too-long if isinstance(src_volume.pool, ThinPool) and \ src_volume.pool.thin_pool == self.pool.thin_pool: # NOQA yield from self._commit(src_volume.path[len('/dev/'):], keep=True) else: cmd = ['create', self.pool._pool_id, # pylint: disable=protected-access self._vid_import.split('/')[1], str(src_volume.size)] yield from qubes_lvm_coro(cmd, self.log) src_path = src_volume.export() cmd = ['dd', 'if=' + src_path, 'of=/dev/' + self._vid_import, 'conv=sparse', 'status=none', 'bs=128K'] if not os.access('/dev/' + self._vid_import, os.W_OK) or \ not os.access(src_path, os.R_OK): cmd.insert(0, 'sudo') p = yield from asyncio.create_subprocess_exec(*cmd) yield from p.wait() if p.returncode != 0: cmd = ['remove', self._vid_import] yield from qubes_lvm_coro(cmd, self.log) raise qubes.storage.StoragePoolException( 'Failed to import volume {!r}, dd exit code: {}'.format( src_volume, p.returncode)) yield from self._commit(self._vid_import) return self @locked @asyncio.coroutine def import_data(self, size): ''' Returns an object that can be `open()`. ''' if self.is_dirty(): raise qubes.storage.StoragePoolException( 'Cannot import data to dirty volume {}, stop the qube first'. format(self.vid)) self.abort_if_import_in_progress() # pylint: disable=protected-access cmd = ['create', self.pool._pool_id, self._vid_import.split('/')[1], str(size)] yield from qubes_lvm_coro(cmd, self.log) yield from reset_cache_coro() devpath = '/dev/' + self._vid_import return devpath @locked @asyncio.coroutine def import_data_end(self, success): '''Either commit imported data, or discard temporary volume''' if not os.path.exists('/dev/' + self._vid_import): raise qubes.storage.StoragePoolException( 'No import operation in progress on {}'.format(self.vid)) if success: yield from self._commit(self._vid_import) else: cmd = ['remove', self._vid_import] yield from qubes_lvm_coro(cmd, self.log) def abort_if_import_in_progress(self): try: devpath = '/dev/' + self._vid_import if os.path.exists(devpath): raise qubes.storage.StoragePoolException( 'Import operation in progress on {}'.format(self.vid)) except AttributeError: # self._vid_import # no vid_import - import definitely not in progress pass def is_dirty(self): if self.save_on_stop: return os.path.exists('/dev/' + self._vid_snap) return False def is_outdated(self): if not self.snap_on_start: return False if self._vid_snap not in size_cache: return False return (size_cache[self._vid_snap]['origin'] != self.source.path.split('/')[-1]) @locked @asyncio.coroutine def revert(self, revision=None): if self.is_dirty(): raise qubes.storage.StoragePoolException( 'Cannot revert dirty volume {}, stop the qube first'.format( self.vid)) self.abort_if_import_in_progress() if revision is None: revision = \ max(self.revisions.items(), key=_revision_sort_key)[0] old_path = '/dev/' + self.vid + '-' + revision if not os.path.exists(old_path): msg = "Volume {!s} has no {!s}".format(self, old_path) raise qubes.storage.StoragePoolException(msg) if self.vid in size_cache: cmd = ['remove', self.vid] yield from qubes_lvm_coro(cmd, self.log) cmd = ['clone', self.vid + '-' + revision, self.vid] yield from qubes_lvm_coro(cmd, self.log) yield from reset_cache_coro() return self @locked @asyncio.coroutine def resize(self, size): ''' Expands volume, throws :py:class:`qubst.storage.qubes.storage.StoragePoolException` if given size is less than current_size ''' if not self.rw: msg = 'Can not resize reađonly volume {!s}'.format(self) raise qubes.storage.StoragePoolException(msg) if size < self.size: raise qubes.storage.StoragePoolException( 'For your own safety, shrinking of %s is' ' disabled (%d < %d). If you really know what you' ' are doing, use `lvresize` on %s manually.' % (self.name, size, self.size, self.vid)) if size == self.size: return if self.is_dirty(): cmd = ['extend', self._vid_snap, str(size)] yield from qubes_lvm_coro(cmd, self.log) elif hasattr(self, '_vid_import') and \ os.path.exists('/dev/' + self._vid_import): cmd = ['extend', self._vid_import, str(size)] yield from qubes_lvm_coro(cmd, self.log) elif self.save_on_stop and not self.snap_on_start: cmd = ['extend', self._vid_current, str(size)] yield from qubes_lvm_coro(cmd, self.log) self._size = size yield from reset_cache_coro() @asyncio.coroutine def _snapshot(self): try: cmd = ['remove', self._vid_snap] yield from qubes_lvm_coro(cmd, self.log) except: # pylint: disable=bare-except pass if self.source is None: cmd = ['clone', self._vid_current, self._vid_snap] else: cmd = ['clone', self.source.path, self._vid_snap] yield from qubes_lvm_coro(cmd, self.log) @locked @asyncio.coroutine def start(self): self.abort_if_import_in_progress() try: if self.snap_on_start or self.save_on_stop: if not self.save_on_stop or not self.is_dirty(): yield from self._snapshot() else: yield from self._reset() finally: yield from reset_cache_coro() return self @locked @asyncio.coroutine def stop(self): try: if self.save_on_stop: yield from self._commit() if self.snap_on_start and not self.save_on_stop: cmd = ['remove', self._vid_snap] yield from qubes_lvm_coro(cmd, self.log) elif not self.snap_on_start and not self.save_on_stop: cmd = ['remove', self.vid] yield from qubes_lvm_coro(cmd, self.log) finally: yield from reset_cache_coro() return self def verify(self): ''' Verifies the volume. ''' if not self.save_on_stop and not self.snap_on_start: # volatile volumes don't need any files return True if self.source is not None: vid = self.source.path[len('/dev/'):] else: vid = self._vid_current try: vol_info = size_cache[vid] if vol_info['attr'][4] != 'a': raise qubes.storage.StoragePoolException( 'volume {} not active'.format(vid)) except KeyError: raise qubes.storage.StoragePoolException( 'volume {} missing'.format(vid)) return True def block_device(self): ''' Return :py:class:`qubes.storage.BlockDevice` for serialization in the libvirt XML template as . ''' if self.snap_on_start or self.save_on_stop: return qubes.storage.BlockDevice( '/dev/' + self._vid_snap, self.name, self.script, self.rw, self.domain, self.devtype) return super().block_device() @property def usage(self): # lvm thin usage always returns at least the same usage as # the parent refresh_cache() try: return qubes.storage.lvm.size_cache[self._vid_current]['usage'] except KeyError: return 0 def pool_exists(pool_id): ''' Return true if pool exists ''' try: vol_info = size_cache[pool_id] return vol_info['attr'][0] == 't' except KeyError: return False def _get_lvm_cmdline(cmd): ''' Build command line for :program:`lvm` call. The purpose of this function is to keep all the detailed lvm options in one place. :param cmd: array of str, where cmd[0] is action and the rest are arguments :return array of str appropriate for subprocess.Popen ''' action = cmd[0] if action == 'remove': lvm_cmd = ['lvremove', '-f', cmd[1]] elif action == 'clone': lvm_cmd = ['lvcreate', '-kn', '-ay', '-s', cmd[1], '-n', cmd[2]] elif action == 'create': lvm_cmd = ['lvcreate', '-T', cmd[1], '-kn', '-ay', '-n', cmd[2], '-V', str(cmd[3]) + 'B'] elif action == 'extend': size = int(cmd[2]) / (1024 * 1024) lvm_cmd = ["lvextend", "-L%s" % size, cmd[1]] elif action == 'activate': lvm_cmd = ['lvchange', '-ay', cmd[1]] elif action == 'rename': lvm_cmd = ['lvrename', cmd[1], cmd[2]] else: raise NotImplementedError('unsupported action: ' + action) if lvm_is_very_old: # old lvm in trusty image used there does not support -k option lvm_cmd = [x for x in lvm_cmd if x != '-kn'] if os.getuid() != 0: cmd = ['sudo', 'lvm'] + lvm_cmd else: cmd = ['lvm'] + lvm_cmd return cmd def _process_lvm_output(returncode, stdout, stderr, log): '''Process output of LVM, determine if the call was successful and possibly log warnings.''' # Filter out warning about intended over-provisioning. # Upstream discussion about missing option to silence it: # https://bugzilla.redhat.com/1347008 err = '\n'.join(line for line in stderr.decode().splitlines() if 'exceeds the size of thin pool' not in line) if stdout: log.debug(stdout) if returncode == 0 and err: log.warning(err) elif returncode != 0: assert err, "Command exited unsuccessful, but printed nothing to stderr" err = err.replace('%', '%%') raise qubes.storage.StoragePoolException(err) return True def qubes_lvm(cmd, log=logging.getLogger('qubes.storage.lvm')): ''' Call :program:`lvm` to execute an LVM operation ''' # the only caller for this non-coroutine version is ThinVolume.export() cmd = _get_lvm_cmdline(cmd) environ = os.environ.copy() environ['LC_ALL'] = 'C.utf8' p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, close_fds=True, env=environ) out, err = p.communicate() return _process_lvm_output(p.returncode, out, err, log) @asyncio.coroutine def qubes_lvm_coro(cmd, log=logging.getLogger('qubes.storage.lvm')): ''' Call :program:`lvm` to execute an LVM operation Coroutine version of :py:func:`qubes_lvm`''' environ = os.environ.copy() environ['LC_ALL'] = 'C.utf8' if cmd[0] == "remove": pre_cmd = ['blkdiscard', '/dev/'+cmd[1]] p = yield from asyncio.create_subprocess_exec(*pre_cmd, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL, close_fds=True, env=environ) _, _ = yield from p.communicate() cmd = _get_lvm_cmdline(cmd) p = yield from asyncio.create_subprocess_exec(*cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, close_fds=True, env=environ) out, err = yield from p.communicate() return _process_lvm_output(p.returncode, out, err, log) def reset_cache(): qubes.storage.lvm.size_cache = init_cache() qubes.storage.lvm.size_cache_time = time.monotonic() @asyncio.coroutine def reset_cache_coro(): qubes.storage.lvm.size_cache = yield from init_cache_coro() qubes.storage.lvm.size_cache_time = time.monotonic() def refresh_cache(): '''Reset size cache, if it's older than 30sec ''' if size_cache_time+30 < time.monotonic(): reset_cache()