def add_watches_to_udf_ancestors(self, volume):
"""Add a inotify watch to volume's ancestors if it's an UDF."""
# This is a platform dependent operation since there are cases in
# which the watches do not have to be added (On windows we do not
# have to add them since we have an opened handle.)
# finally, check that UDF is ok in disk
if not access(volume.path):
# if we cannot access the UDF lets return false and do
# nothing
return defer.succeed(False)
return self.monitor.add_watches_to_udf_ancestors(volume)
def add_watches_to_udf_ancestors(self, volume):
"""Add a inotify watch to volume's ancestors if it's an UDF."""
added_watches = []
def revert_watches():
"""Restore the just added watches and unsubscribe volume."""
for path in added_watches:
self.eq.rm_watch(path)
for ancestor in volume.ancestors:
# check that ancestor is still there
if not access(ancestor):
self.log.info("Tree broken at path: %r", volume.path)
revert_watches()
defer.returnValue(False)
self.log.debug("Adding watch to UDF's ancestor %r", ancestor)
really_added = yield self.eq.add_watch(ancestor)
# only note it for the revert if the watch was not there before
if really_added:
added_watches.append(ancestor)
# all is ok
defer.returnValue(True)
