InstanceRecreateDisks: new assertion for node locks

Make sure that all the nodes where a disk operation is peformed are locked.

Signed-off-by: Bernardo Dal Seno <bdalseno@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>

lib/cmdlib.py

@@ -7337,6 +7337,9 @@ class LUInstanceRecreateDisks(LogicalUnit):
     if self.op.nodes:
       self.cfg.Update(instance, feedback_fn)
+    # All touched nodes must be locked
+    mylocks = self.owned_locks(locking.LEVEL_NODE)
+    assert mylocks.issuperset(frozenset(instance.all_nodes))
     _CreateDisks(self, instance, to_skip=to_skip)