storage/lvm: use temporary volume for data import
Do not write directly to main volume, instead create temporary volume and only commit it to the main one when operation is finished. This solve multiple problems: - import operation can be aborted, without data loss - importing new data over existing volume will not leave traces of previous content - especially when importing smaller volume to bigger one - import operation can be reverted - it create separate revision, similar to start/stop - easier to prevent qube from starting during import operation - template still can be used when importing new version QubesOS/qubes-issues#2256
This commit is contained in:
Marek Marczykowski-Górecki
parent
aea0de35ad
commit
2b80f0c044
@ -159,7 +159,7 @@ class ThinPool(qubes.storage.Pool):
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continue
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if vol_info['pool_lv'] != self.thin_pool:
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continue
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if vid.endswith('-snap'):
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if vid.endswith('-snap') or vid.endswith('-import'):
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# implementation detail volume
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continue
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if vid.endswith('-back'):
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@ -249,6 +249,8 @@ class ThinVolume(qubes.storage.Volume):
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if self.snap_on_start or self.save_on_stop:
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self._vid_snap = self.vid + '-snap'
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if self.save_on_stop:
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self._vid_import = self.vid + '-import'
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self._size = size
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@ -409,6 +411,13 @@ class ThinVolume(qubes.storage.Volume):
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except AttributeError:
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pass
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try:
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if os.path.exists('/dev/' + self._vid_import):
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cmd = ['remove', self._vid_import]
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qubes_lvm(cmd, self.log)
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except AttributeError:
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pass
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self._remove_revisions(self.revisions.keys())
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if not os.path.exists(self.path):
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return
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@ -434,36 +443,74 @@ class ThinVolume(qubes.storage.Volume):
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raise qubes.storage.StoragePoolException(
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'Cannot import to dirty volume {} -'
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' start and stop a qube to cleanup'.format(self.vid))
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self.abort_if_import_in_progress()
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# HACK: neat trick to speed up testing if you have same physical thin
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# pool assigned to two qubes-pools i.e: qubes_dom0 and test-lvm
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# pylint: disable=line-too-long
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if isinstance(src_volume.pool, ThinPool) and \
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src_volume.pool.thin_pool == self.pool.thin_pool: # NOQA
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self._commit(src_volume.path, keep=True)
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self._commit(src_volume.path[len('/dev/'):], keep=True)
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else:
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cmd = ['create', self.pool._pool_id, self._vid_snap.split('/')[1],
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cmd = ['create',
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self.pool._pool_id, # pylint: disable=protected-access
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self._vid_import.split('/')[1],
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str(src_volume.size)]
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qubes_lvm(cmd)
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qubes_lvm(cmd, self.log)
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src_path = src_volume.export()
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cmd = ['dd', 'if=' + src_path, 'of=/dev/' + self._vid_snap,
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'conv=sparse']
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cmd = ['dd', 'if=' + src_path, 'of=/dev/' + self._vid_import,
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'conv=sparse', 'status=none']
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if not os.access('/dev/' + self._vid_import, os.W_OK) or \
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not os.access(src_path, os.R_OK):
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cmd.insert(0, 'sudo')
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p = yield from asyncio.create_subprocess_exec(*cmd)
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yield from p.wait()
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if p.returncode != 0:
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cmd = ['remove', self._vid_snap]
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qubes_lvm(cmd)
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cmd = ['remove', self._vid_import]
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qubes_lvm(cmd, self.log)
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raise qubes.storage.StoragePoolException(
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'Failed to import volume {!r}, dd exit code: {}'.format(
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src_volume, p.returncode))
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self._commit()
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self._commit(self._vid_import)
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return self
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def import_data(self):
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''' Returns an object that can be `open()`. '''
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devpath = '/dev/' + self.vid
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if self.is_dirty():
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raise qubes.storage.StoragePoolException(
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'Cannot import data to dirty volume {}, stop the qube first'.
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format(self.vid))
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self.abort_if_import_in_progress()
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# pylint: disable=protected-access
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cmd = ['create', self.pool._pool_id, self._vid_import.split('/')[1],
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str(self.size)]
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qubes_lvm(cmd, self.log)
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reset_cache()
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devpath = '/dev/' + self._vid_import
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return devpath
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def import_data_end(self, success):
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'''Either commit imported data, or discard temporary volume'''
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if not os.path.exists('/dev/' + self._vid_import):
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raise qubes.storage.StoragePoolException(
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'No import operation in progress on {}'.format(self.vid))
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if success:
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self._commit(self._vid_import)
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else:
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cmd = ['remove', self._vid_import]
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qubes_lvm(cmd, self.log)
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def abort_if_import_in_progress(self):
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try:
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devpath = '/dev/' + self._vid_import
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if os.path.exists(devpath):
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raise qubes.storage.StoragePoolException(
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'Import operation in progress on {}'.format(self.vid))
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except AttributeError: # self._vid_import
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# no vid_import - import definitely not in progress
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pass
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def is_dirty(self):
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if self.save_on_stop:
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return os.path.exists('/dev/' + self._vid_snap)
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@ -482,6 +529,7 @@ class ThinVolume(qubes.storage.Volume):
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raise qubes.storage.StoragePoolException(
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'Cannot revert dirty volume {}, stop the qube first'.format(
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self.vid))
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self.abort_if_import_in_progress()
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if revision is None:
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revision = \
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max(self.revisions.items(), key=_revision_sort_key)[0]
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@ -520,6 +568,10 @@ class ThinVolume(qubes.storage.Volume):
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if self.is_dirty():
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cmd = ['extend', self._vid_snap, str(size)]
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qubes_lvm(cmd, self.log)
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elif hasattr(self, '_vid_import') and \
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os.path.exists('/dev/' + self._vid_import):
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cmd = ['extend', self._vid_import, str(size)]
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qubes_lvm(cmd, self.log)
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elif self.save_on_stop or not self.snap_on_start:
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cmd = ['extend', self._vid_current, str(size)]
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qubes_lvm(cmd, self.log)
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@ -538,8 +590,8 @@ class ThinVolume(qubes.storage.Volume):
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cmd = ['clone', self.source.path, self._vid_snap]
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qubes_lvm(cmd, self.log)
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def start(self):
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self.abort_if_import_in_progress()
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try:
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if self.snap_on_start or self.save_on_stop:
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if not self.save_on_stop or not self.is_dirty():
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@ -649,6 +649,65 @@ class TC_00_ThinPool(ThinPoolBase):
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volume.remove()
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def test_030_import_data(self):
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''' Test volume import'''
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config = {
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'name': 'root',
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'pool': self.pool.name,
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'save_on_stop': True,
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'rw': True,
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'revisions_to_keep': 2,
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'size': qubes.config.defaults['root_img_size'],
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}
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vm = qubes.tests.storage.TestVM(self)
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volume = self.app.get_pool(self.pool.name).init_volume(vm, config)
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volume.create()
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current_uuid = self._get_lv_uuid(volume.path)
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self.assertFalse(volume.is_dirty())
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import_path = volume.import_data()
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import_uuid = self._get_lv_uuid(import_path)
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self.assertNotEqual(current_uuid, import_uuid)
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# success - commit data
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volume.import_data_end(True)
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new_current_uuid = self._get_lv_uuid(volume.path)
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self.assertEqual(new_current_uuid, import_uuid)
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revisions = volume.revisions
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self.assertEqual(len(revisions), 1)
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revision = revisions.popitem()[0]
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self.assertEqual(current_uuid,
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self._get_lv_uuid(volume.vid + '-' + revision))
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self.assertFalse(os.path.exists(import_path), import_path)
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volume.remove()
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def test_031_import_data_fail(self):
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''' Test volume import'''
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config = {
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'name': 'root',
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'pool': self.pool.name,
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'save_on_stop': True,
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'rw': True,
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'revisions_to_keep': 2,
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'size': qubes.config.defaults['root_img_size'],
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}
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vm = qubes.tests.storage.TestVM(self)
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volume = self.app.get_pool(self.pool.name).init_volume(vm, config)
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volume.create()
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current_uuid = self._get_lv_uuid(volume.path)
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self.assertFalse(volume.is_dirty())
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import_path = volume.import_data()
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import_uuid = self._get_lv_uuid(import_path)
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self.assertNotEqual(current_uuid, import_uuid)
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# fail - discard data
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volume.import_data_end(False)
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new_current_uuid = self._get_lv_uuid(volume.path)
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self.assertEqual(new_current_uuid, current_uuid)
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revisions = volume.revisions
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self.assertEqual(len(revisions), 0)
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self.assertFalse(os.path.exists(import_path), import_path)
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volume.remove()
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@skipUnlessLvmPoolExists
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class TC_01_ThinPool(ThinPoolBase, qubes.tests.SystemTestCase):
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