Qubes/core-admin
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

storage/reflink: split @_unblock into @_coroutinized @_locked

Browse Source 
And change the volume lock from an asyncio.Lock to a threading.Lock -
locking is now handled before coroutinization.

This will allow the coroutinized resize() and a new *not* coroutinized
size() getter from one of the next commits ("storage/reflink: preferably
get volume size from image size") to both run under the volume lock.
This commit is contained in:
Rusty Bird 2019-06-23 12:47:58 +00:00
parent ab929baa38
commit 4c9c0a88d5
No known key found for this signature in database
GPG Key ID: 469D78F47AAF2ADF
1 changed files with 37 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

55
qubes/storage/reflink.py
View File

@ -32,6 +32,7 @@ import logging
import os
import subprocess
import tempfile
import threading
from contextlib import contextmanager, suppress
import qubes.storage
@ -117,36 +118,47 @@ class ReflinkPool(qubes.storage.Pool):
self.dir_path)
def _unblock(method):
''' Decorator transforming a synchronous volume method into a
coroutine that runs the original method in the event loop's
thread-based default executor, under a per-volume lock.
def _coroutinized(function):
''' Decorator transforming a synchronous function into a coroutine
that runs the function in the event loop's thread-based
default executor.
'''
@asyncio.coroutine
@functools.wraps(function)
def wrapper(*args, **kwargs):
return (yield from asyncio.get_event_loop().run_in_executor(
None, functools.partial(function, *args, **kwargs)))
return wrapper
def _locked(method):
''' Decorator transforming a synchronous volume method to run
under the volume lock.
'''
@functools.wraps(method)
def wrapper(self, *args, **kwargs):
with (yield from self._lock): # pylint: disable=protected-access
return (yield from asyncio.get_event_loop().run_in_executor(
None, functools.partial(method, self, *args, **kwargs)))
with self._lock: # pylint: disable=protected-access
return method(self, *args, **kwargs)
return wrapper
class ReflinkVolume(qubes.storage.Volume):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self._lock = asyncio.Lock()
self._lock = threading.Lock()
self._path_vid = os.path.join(self.pool.dir_path, self.vid)
self._path_clean = self._path_vid + '.img'
self._path_dirty = self._path_vid + '-dirty.img'
self._path_import = self._path_vid + '-import.img'
self.path = self._path_dirty
@_unblock
@_coroutinized
@_locked
def create(self):
if self.save_on_stop and not self.snap_on_start:
_create_sparse_file(self._path_clean, self.size)
return self
@_unblock
@_coroutinized
@_locked
def verify(self):
if self.snap_on_start:
img = self.source._path_clean # pylint: disable=protected-access
@ -160,7 +172,8 @@ class ReflinkVolume(qubes.storage.Volume):
raise qubes.storage.StoragePoolException(
'Missing image file {!r} for volume {}'.format(img, self.vid))
@_unblock
@_coroutinized
@_locked
def remove(self):
''' Drop volume object from pool; remove volume images from
oldest to newest; remove empty VM directory.
@ -189,7 +202,8 @@ class ReflinkVolume(qubes.storage.Volume):
def is_dirty(self):
return self.save_on_stop and os.path.exists(self._path_dirty)
@_unblock
@_coroutinized
@_locked
def start(self):
self._cleanup()
if self.is_dirty(): # implies self.save_on_stop
@ -203,7 +217,8 @@ class ReflinkVolume(qubes.storage.Volume):
_create_sparse_file(self._path_dirty, self.size)
return self
@_unblock
@_coroutinized
@_locked
def stop(self):
if self.save_on_stop:
self._commit(self._path_dirty)
@ -232,7 +247,8 @@ class ReflinkVolume(qubes.storage.Volume):
for number, timestamp in list(self.revisions.items())[:-keep or None]:
_remove_file(self._path_revision(number, timestamp))
@_unblock
@_coroutinized
@_locked
def revert(self, revision=None):
if self.is_dirty():
raise qubes.storage.StoragePoolException(
@ -246,7 +262,8 @@ class ReflinkVolume(qubes.storage.Volume):
_rename_file(path_revision, self._path_clean)
return self
@_unblock
@_coroutinized
@_locked
def resize(self, size):
''' Resize a read-write volume image; notify any corresponding
loop devices of the size change.
@ -271,7 +288,8 @@ class ReflinkVolume(qubes.storage.Volume):
'Cannot export: {} is not save_on_stop'.format(self.vid))
return self._path_clean
@_unblock
@_coroutinized
@_locked
def import_data(self):
if not self.save_on_stop:
raise NotImplementedError(
@ -286,9 +304,10 @@ class ReflinkVolume(qubes.storage.Volume):
_remove_file(self._path_import)
return self
import_data_end = _unblock(_import_data_end)
import_data_end = _coroutinized(_locked(_import_data_end))
@_unblock
@_coroutinized
@_locked
def import_volume(self, src_volume):
if not self.save_on_stop:
return self