Commit c4a2fee1 authored by Guido Trotter's avatar Guido Trotter
Browse files

LogicalUnit._LockInstancesNodes helper function

This function is used to lock instances' primary and secondary nodes
after locking instances themselves.

Reviewed-by: iustinp
parent 3977a4c1
......@@ -84,6 +84,8 @@ class LogicalUnit(object):
self.context = context
self.needed_locks = None
self.share_locks = dict(((i, 0) for i in locking.LEVELS))
# Used to force good behavior when calling helper functions
self.recalculate_locks = {}
self.__ssh = None
for attr_name in self._OP_REQP:
......@@ -262,6 +264,43 @@ class LogicalUnit(object):
self.needed_locks[locking.LEVEL_INSTANCE] = expanded_name
self.op.instance_name = expanded_name
def _LockInstancesNodes(self):
"""Helper function to declare instances' nodes for locking.
This function should be called after locking one or more instances to lock
their nodes. Its effect is populating self.needed_locks[locking.LEVEL_NODE]
with all primary or secondary nodes for instances already locked and
present in self.needed_locks[locking.LEVEL_INSTANCE].
It should be called from DeclareLocks, and for safety only works if
self.recalculate_locks[locking.LEVEL_NODE] is set.
In the future it may grow parameters to just lock some instance's nodes, or
to just lock primaries or secondary nodes, if needed.
If should be called in DeclareLocks in a way similar to:
if level == locking.LEVEL_NODE:
assert locking.LEVEL_NODE in self.recalculate_locks, \
"_LockInstancesNodes helper function called with no nodes to recalculate"
# TODO: check if we're really been called with the instance locks held
# For now we'll replace self.needed_locks[locking.LEVEL_NODE], but in the
# future we might want to have different behaviors depending on the value
# of self.recalculate_locks[locking.LEVEL_NODE]
wanted_nodes = []
for instance_name in self.needed_locks[locking.LEVEL_INSTANCE]:
instance = self.context.cfg.GetInstanceInfo(instance_name)
self.needed_locks[locking.LEVEL_NODE] = wanted_nodes
del self.recalculate_locks[locking.LEVEL_NODE]
class NoHooksLU(LogicalUnit):
"""Simple LU which runs no hooks.
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