core-admin/qubes/storage/lvm.py
Marek Marczykowski-Górecki 37dbf29bc1
storage/lvm: don't fail on removing already removed volumes
This may happen when removing not fully created VM.

QubesOS/qubes-issues#2256
2016-11-04 14:18:55 +01:00

469 lines
15 KiB
Python

# vim: fileencoding=utf-8
# pylint: disable=abstract-method
#
# The Qubes OS Project, http://www.qubes-os.org
#
# Copyright (C) 2016 Bahtiar `kalkin-` Gadimov <bahtiar@gadimov.de>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
''' Driver for storing vm images in a LVM thin pool '''
import logging
import os
import subprocess
import qubes
class ThinPool(qubes.storage.Pool):
''' LVM Thin based pool implementation
''' # pylint: disable=protected-access
size_cache = None
driver = 'lvm_thin'
def __init__(self, volume_group, thin_pool, revisions_to_keep=1, **kwargs):
super(ThinPool, self).__init__(revisions_to_keep=revisions_to_keep,
**kwargs)
self.volume_group = volume_group
self.thin_pool = thin_pool
self._pool_id = "{!s}/{!s}".format(volume_group, thin_pool)
self.log = logging.getLogger('qube.storage.lvm.%s' % self._pool_id)
def clone(self, source, target):
cmd = ['clone', str(source), str(target)]
qubes_lvm(cmd, self.log)
return target
def _commit(self, volume):
msg = "Trying to commit {!s}, but it has save_on_stop == False"
msg = msg.format(volume)
assert volume.save_on_stop, msg
msg = "Trying to commit {!s}, but it has rw == False"
msg = msg.format(volume)
assert volume.rw, msg
assert hasattr(volume, '_vid_snap')
cmd = ['remove', volume.vid + "-back"]
qubes_lvm(cmd, self.log)
cmd = ['clone', volume._vid_snap, volume.vid + "-back"]
qubes_lvm(cmd, self.log)
cmd = ['remove', volume.vid]
qubes_lvm(cmd, self.log)
cmd = ['clone', volume._vid_snap, volume.vid]
qubes_lvm(cmd, self.log)
cmd = ['remove', volume._vid_snap]
qubes_lvm(cmd, self.log)
@property
def config(self):
return {
'name': self.name,
'volume_group': self.volume_group,
'thin_pool': self.thin_pool,
'driver': ThinPool.driver
}
def create(self, volume):
assert volume.vid
assert volume.size
if volume.source:
# will clone in start()
return volume
elif not volume._is_volatile:
cmd = [
'create',
self._pool_id,
volume.vid.split('/', 1)[1],
str(volume.size)
]
qubes_lvm(cmd, self.log)
reset_cache()
return volume
def destroy(self):
pass # TODO Should we remove an existing pool?
def export(self, volume):
''' Returns an object that can be `open()`. '''
devpath = '/dev/' + volume.vid
if not os.access(devpath, os.R_OK):
# FIXME: convert to udev rules, and drop after introducing qubesd
subprocess.check_call(['sudo', 'chgrp', 'qubes', devpath])
subprocess.check_call(['sudo', 'chmod', 'g+rw', devpath])
return devpath
def init_volume(self, vm, volume_config):
''' Initialize a :py:class:`qubes.storage.Volume` from `volume_config`.
'''
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}/{!s}-{!s}".format(
self.volume_group, vm_name, volume_config['name'])
volume_config['volume_group'] = self.volume_group
return ThinVolume(**volume_config)
def import_volume(self, dst_pool, dst_volume, src_pool, src_volume):
if not src_volume.save_on_stop:
return dst_volume
src_path = src_pool.export(src_volume)
# 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_pool, ThinPool) and src_pool.thin_pool == dst_pool.thin_pool: # NOQA
return self.clone(src_volume, dst_volume)
else:
dst_volume = self.create(dst_volume)
cmd = ['sudo', 'dd', 'if=' + src_path, 'of=/dev/' + dst_volume.vid,
'conv=sparse']
subprocess.check_call(cmd)
reset_cache()
return dst_volume
def is_dirty(self, volume):
if volume.save_on_stop:
return os.path.exists(volume.path + '-snap')
return False
def remove(self, volume):
assert volume.vid
if self.is_dirty(volume):
cmd = ['remove', volume._vid_snap]
qubes_lvm(cmd, self.log)
if not os.path.exists(volume.path):
return
cmd = ['remove', volume.vid]
qubes_lvm(cmd, self.log)
reset_cache()
def rename(self, volume, old_name, new_name):
''' Called when the domain changes its name '''
new_vid = "{!s}/{!s}-{!s}".format(self.volume_group, new_name,
volume.name)
if volume.save_on_stop:
cmd = ['clone', volume.vid, new_vid]
qubes_lvm(cmd, self.log)
if volume.save_on_stop or volume._is_volatile:
cmd = ['remove', volume.vid]
qubes_lvm(cmd, self.log)
volume.vid = new_vid
if not volume._is_volatile:
volume._vid_snap = volume.vid + '-snap'
reset_cache()
return volume
def revert(self, volume, revision=None):
old_path = volume.path + '-back'
if not os.path.exists(old_path):
msg = "Volume {!s} has no {!s}".format(volume, old_path)
raise qubes.storage.StoragePoolException(msg)
cmd = ['remove', volume.vid]
qubes_lvm(cmd, self.log)
cmd = ['clone', volume.vid + '-back', volume.vid]
qubes_lvm(cmd, self.log)
reset_cache()
return volume
def resize(self, volume, size):
''' Expands volume, throws
:py:class:`qubst.storage.qubes.storage.StoragePoolException` if
given size is less than current_size
'''
if not volume.rw:
msg = 'Can not resize reađonly volume {!s}'.format(volume)
raise qubes.storage.StoragePoolException(msg)
if size <= volume.size:
raise qubes.storage.StoragePoolException(
'For your own safety, shrinking of %s is'
' disabled. If you really know what you'
' are doing, use `lvresize` on %s manually.' %
(volume.name, volume.vid))
cmd = ['extend', volume.vid, str(size)]
qubes_lvm(cmd, self.log)
reset_cache()
def _reset(self, volume):
try:
self.remove(volume)
except qubes.storage.StoragePoolException:
pass
self.create(volume)
def setup(self):
pass # TODO Should we create a non existing pool?
def start(self, volume):
if volume._is_snapshot:
self._snapshot(volume)
elif volume._is_volatile:
self._reset(volume)
else:
if not self.is_dirty(volume):
self._snapshot(volume)
reset_cache()
return volume
def stop(self, volume):
if volume.save_on_stop:
self._commit(volume)
if volume._is_snapshot:
cmd = ['remove', volume._vid_snap]
qubes_lvm(cmd, self.log)
elif volume._is_volatile:
cmd = ['remove', volume.vid]
qubes_lvm(cmd, self.log)
else:
cmd = ['remove', volume._vid_snap]
qubes_lvm(cmd, self.log)
reset_cache()
return volume
def _snapshot(self, volume):
try:
cmd = ['remove', volume._vid_snap]
qubes_lvm(cmd, self.log)
except: # pylint: disable=bare-except
pass
if volume.source is None:
cmd = ['clone', volume.vid, volume._vid_snap]
else:
cmd = ['clone', str(volume.source), volume._vid_snap]
qubes_lvm(cmd, self.log)
def verify(self, volume):
''' Verifies the volume. '''
try:
vol_info = size_cache[volume.vid]
return vol_info['attr'][4] == 'a'
except KeyError:
return False
@property
def 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
config = {
'pool': self.name,
'vid': vid,
'name': vid,
'volume_group': self.volume_group,
'rw': vol_info['attr'][1] == 'w',
}
volumes += [ThinVolume(**config)]
return volumes
def _reset_volume(self, volume):
''' Resets a volatile volume '''
assert volume.volume_type == 'volatile', \
'Expected a volatile volume, but got {!r}'.format(volume)
self.log.debug('Resetting volatile ' + volume.vid)
cmd = ['remove', volume.vid]
qubes_lvm(cmd, self.log)
cmd = ['create', self._pool_id, volume.vid.split('/')[1],
str(volume.size)]
qubes_lvm(cmd, self.log)
def init_cache(log=logging.getLogger('qube.storage.lvm')):
cmd = ['lvs', '--noheadings', '-o',
'vg_name,pool_lv,name,lv_size,data_percent,lv_attr',
'--units', 'b', '--separator', ',']
if os.getuid() != 0:
cmd.insert(0, 'sudo')
p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
close_fds=True)
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)
result = {}
for line in out.splitlines():
line = line.strip()
pool_name, pool_lv, name, size, usage_percent, attr = line.split(',', 5)
if '' in [pool_name, pool_lv, name, size, usage_percent]:
continue
name = pool_name + "/" + name
size = int(size[:-1])
usage = int(size / 100 * float(usage_percent))
result[name] = {'size': size, 'usage': usage, 'pool_lv': pool_lv,
'attr': attr}
return result
size_cache = init_cache()
class ThinVolume(qubes.storage.Volume):
''' Default LVM thin volume implementation
''' # pylint: disable=too-few-public-methods
def __init__(self, volume_group, size=0, **kwargs):
self.volume_group = volume_group
super(ThinVolume, self).__init__(size=size, **kwargs)
if self.snap_on_start and self.source is None:
msg = "snap_on_start specified on {!r} but no volume source set"
msg = msg.format(self.name)
raise qubes.storage.StoragePoolException(msg)
elif not self.snap_on_start and self.source is not None:
msg = "source specified on {!r} but no snap_on_start set"
msg = msg.format(self.name)
raise qubes.storage.StoragePoolException(msg)
self.path = '/dev/' + self.vid
if not self._is_volatile:
self._vid_snap = self.vid + '-snap'
self._size = size
@property
def revisions(self):
path = self.path + '-back'
if os.path.exists(path):
seconds = os.path.getctime(path)
iso_date = qubes.storage.isodate(seconds).split('.', 1)[0]
return {iso_date: path}
return {}
@property
def _is_origin(self):
return not self.snap_on_start and self.save_on_stop
@property
def _is_origin_snapshot(self):
return self.snap_on_start and self.save_on_stop
@property
def _is_snapshot(self):
return self.snap_on_start and not self.save_on_stop
@property
def _is_volatile(self):
return not self.snap_on_start and not self.save_on_stop
@property
def size(self):
try:
return qubes.storage.lvm.size_cache[self.vid]['size']
except KeyError:
return self._size
@size.setter
def size(self, _):
raise qubes.storage.StoragePoolException(
"You shouldn't use lvm size setter")
def block_device(self):
''' Return :py:class:`qubes.devices.BlockDevice` for serialization in
the libvirt XML template as <disk>.
'''
if not self._is_volatile:
return qubes.devices.BlockDevice(
'/dev/' + self._vid_snap, self.name, self.script,
self.rw, self.domain, self.devtype)
else:
return super(ThinVolume, self).block_device()
@property
def usage(self): # lvm thin usage always returns at least the same usage as
# the parent
try:
return qubes.storage.lvm.size_cache[self.vid]['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 qubes_lvm(cmd, log=logging.getLogger('qube.storage.lvm')):
''' Call :program:`lvm` to execute an LVM operation '''
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]) / (1000 * 1000)
lvm_cmd = ["lvextend", "-L%s" % size, cmd[1]]
else:
raise NotImplementedError('unsupported action: ' + action)
if os.getuid() != 0:
cmd = ['sudo', 'lvm'] + lvm_cmd
else:
cmd = ['lvm'] + lvm_cmd
p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
close_fds=True)
out, err = p.communicate()
return_code = p.returncode
if out:
log.debug(out)
if return_code == 0 and err:
log.warning(err)
elif return_code != 0:
assert err, "Command exited unsuccessful, but printed nothing to stderr"
raise qubes.storage.StoragePoolException(err)
return True
def reset_cache():
qubes.storage.lvm.size_cache = init_cache()