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lvm2 pool: Export immutable snapshot of volume #461

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lvm2 pool: Export immutable snapshot of volume #461

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b5dd800
lvm2 pool: Export immutable snapshot of volume
DemiMarie Apr 1, 2022
3f327c6
Remove a redundant cache invalidation
DemiMarie Apr 8, 2022
5eb6240
Remove the 'activate' command
DemiMarie Apr 1, 2022
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38 changes: 28 additions & 10 deletions qubes/storage/lvm.py
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Original file line number Diff line number Diff line change
Expand Up @@ -156,7 +156,8 @@ def list_volumes(self):
continue
if vol_info['pool_lv'] != self.thin_pool:
continue
if vid.endswith('-snap') or vid.endswith('-import'):
if vid.endswith('-snap') or vid.endswith('-import') or \
vid.endswith('+export'):
# implementation detail volume
continue
if vid.endswith('-back'):
Expand Down Expand Up @@ -292,6 +293,7 @@ def __init__(self, volume_group, **kwargs):
self._vid_snap = self.vid + '-snap'
if self.save_on_stop:
self._vid_import = self.vid + '-import'
self._is_exporting = False

@property
def path(self):
Expand Down Expand Up @@ -409,7 +411,6 @@ async def _commit(self, vid_to_commit=None, keep=False):
cmd = ['rename', self.vid,
'{}-{}-back'.format(self.vid, int(time.time()))]
await qubes_lvm_coro(cmd, self.log)
await reset_cache_coro()

cmd = ['clone' if keep else 'rename',
vid_to_commit,
Expand Down Expand Up @@ -470,13 +471,31 @@ async def remove(self):
# pylint: disable=protected-access
self.pool._volume_objects_cache.pop(self.vid, None)

async def export(self):
@property
def _vid_export(self) -> str:
return self.vid + '+export'

@property
def _path_export(self) -> str:
return '/dev/' + self._vid_export

async def export(self) -> str:
''' Returns an object that can be `open()`. '''
# make sure the device node is available
cmd = ['activate', self.path]
await qubes_lvm_coro(cmd, self.log)
devpath = self.path
return devpath
vid_export = self._vid_export
export_path = self._path_export
if not os.path.exists(export_path):
cmd = ['clone', self._vid_current, vid_export]
await qubes_lvm_coro(cmd, self.log)
self._is_exporting = True
return export_path

async def export_end(self, path: str) -> None:
assert path == self._path_export, \
f'Refusing to remove incorrect path {path!r} ' \
f'(expected {self._path_export!r})'
await self._remove_if_exists(self._vid_export)
self._is_exporting = False

@qubes.storage.Volume.locked
async def import_volume(self, src_volume):
Expand Down Expand Up @@ -681,6 +700,8 @@ async def stop(self):
changed = await self._remove_if_exists(self._vid_snap)
else:
changed = await self._remove_if_exists(self.vid)
if not self._is_exporting:
await self._remove_if_exists(self._vid_export)
finally:
if changed:
await reset_cache_coro()
Expand Down Expand Up @@ -767,9 +788,6 @@ def _get_lvm_cmdline(cmd):
elif action == 'extend':
assert len(cmd) == 3, 'wrong number of arguments for extend'
lvm_cmd = ["lvextend", "--size=" + cmd[2] + 'B', '--', cmd[1]]
elif action == 'activate':
assert len(cmd) == 2, 'wrong number of arguments for activate'
lvm_cmd = ['lvchange', '--activate=y', '--', cmd[1]]
elif action == 'rename':
assert len(cmd) == 3, 'wrong number of arguments for rename'
lvm_cmd = ['lvrename', '--', cmd[1], cmd[2]]
Expand Down