From c4a2fee1c91fe6ff391e976508321f75b9ae68c6 Mon Sep 17 00:00:00 2001
From: Guido Trotter <ultrotter@google.com>
Date: Wed, 30 Jul 2008 11:30:29 +0000
Subject: [PATCH] LogicalUnit._LockInstancesNodes helper function
This function is used to lock instances' primary and secondary nodes
after locking instances themselves.
Reviewed-by: iustinp
---
lib/cmdlib.py | 39 +++++++++++++++++++++++++++++++++++++++
1 file changed, 39 insertions(+)
diff --git a/lib/cmdlib.py b/lib/cmdlib.py
index a6d759f07..6789a3543 100644
--- a/lib/cmdlib.py
+++ b/lib/cmdlib.py
@@ -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:
+ self._LockInstancesNodes()
+
+ """
+ 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)
+ wanted_nodes.append(instance.primary_node)
+ wanted_nodes.extend(instance.secondary_nodes)
+ 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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