[JCR-3977] New cluster node resets timeout of the open-scoped lock

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 2.11.3
• Component/s: JCR 2.0
• Assignee: Unassigned
• Reporter: Illia Khokholkov
• Created: 18/May/16 03:23
• Updated: 18/May/16 03:23

Description

Problem

Suppose we have an active open-scoped lock with a timeout set to 5 minutes (the time to wait before the lock gets automatically released). Such a lock would be present in the data store, e.g. Oracle DBMS, in the following format (for instance, judging from the content of the persisted BLOB):

0899d423-c9e4-4d9b-a46e-a5055df8a23c-2,300

Consider that before the lock is unlocked, a new org.apache.jackrabbit.core.cluster.ClusterNode joins the cluster. When synchronization takes places for the new member of the cluster, the timeout of the existing lock gets updated to the Long.MAX_VALUE, ignoring the previously existing value (the absence of the ,N indicates, essentially, no expiry):

0899d423-c9e4-4d9b-a46e-a5055df8a23c-2

On the client side, if the branch of code that handles unlocking is never reached, e.g. due to JVM failure, the originally locked node now becomes permanently locked. I am aware of the background thread that every so often looks for the expired open-scoped locks and attempts to get rid of them. However, to such a handler, the lock would still appear as active and not expired.

Possible Reason

When a cluster node processes the lock record, for a lock operation it talks to the lock event listener:

if (record.isLock()) {
    listener.externalLock(record.getNodeId(), record.isDeep(),
            record.getOwner());
}

That operation, in turn, defines a new timeout value for the lock, ignoring the previously set one (the one that was obtained from the persistent storage):

// create lock token
InternalLockInfo info = new InternalLockInfo(
        nodeId, false, isDeep, lockOwner, Long.MAX_VALUE);

Questions

1. Am I overlooking something evident here that would tell me that the observed behavior is the one I should expect? Thanks!