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lvm2/daemons/lvmdbusd/udevwatch.py
Tony Asleson e53454d6de lvmdbusd: Use work queue for queries too
We need to place query operations in the queue to prevent the case where
a client knows of something before the service does.  For example if a
client creates a PV/VG/LV outside of the dbus API and then immediately
tries to lookup and use that resource in the lvm dbus service it should
be present.  By placing the queries in the work queue any previous
refresh operation will complete before we process the query.
2017-03-09 16:39:47 -06:00

71 lines
1.7 KiB
Python

# Copyright (C) 2015-2016 Red Hat, Inc. All rights reserved.
#
# This copyrighted material is made available to anyone wishing to use,
# modify, copy, or redistribute it subject to the terms and conditions
# of the GNU General Public License v.2.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import pyudev
import threading
from . import cfg
from .request import RequestEntry
from . import utils
observer = None
observer_lock = threading.RLock()
def _udev_event():
utils.log_debug("Processing udev event")
cfg.load()
# noinspection PyUnusedLocal
def filter_event(action, device):
# Filter for events of interest and add a request object to be processed
# when appropriate.
refresh = False
if '.ID_FS_TYPE_NEW' in device:
fs_type_new = device['.ID_FS_TYPE_NEW']
if 'LVM' in fs_type_new:
refresh = True
elif fs_type_new == '':
# Check to see if the device was one we knew about
if 'DEVNAME' in device:
found = cfg.om.get_object_by_lvm_id(device['DEVNAME'])
if found:
refresh = True
if 'DM_LV_NAME' in device:
refresh = True
if refresh:
# Place this on the queue so any other operations will sequence behind it
r = RequestEntry(
-1, _udev_event, (), None, None, False)
cfg.worker_q.put(r)
def add():
with observer_lock:
global observer
context = pyudev.Context()
monitor = pyudev.Monitor.from_netlink(context)
monitor.filter_by('block')
observer = pyudev.MonitorObserver(monitor, filter_event)
observer.start()
def remove():
with observer_lock:
global observer
if observer:
observer.stop()
observer = None
return True
return False