[jboss-jira] [JBoss JIRA] Commented: (JGRP-384) DistributedLockManager.unlock() throws an exception if one of the group members terminates.

DistributedLockManager.unlock() throws an exception if one of the group members terminates. ------------------------------------------------------------------------------------------- Key: JGRP-384 URL: http://jira.jboss.com/jira/browse/JGRP-384 Project: JGroups Issue Type: Bug Affects Versions: 2.4 Environment: Suse Linux 10.1 Desktop java version "1.5.0_07" Dell Optiplex GX280 Reporter: Sean Landis Assigned To: Bela Ban Fix For: 2.6 I am trying to use the DLM to implement a failover mechanism. Two identical processes are started. One acquires the lock and becomes the primary; the other can't acquire the lock and becomes the backup. The primary does it's processing. The backup checks periodically if it can get the lock. Should the primary fail, the backup will acquire the lock and do the processing. This works fine. The problem I am having is if both are running, the backup fails, and the primary tries to unlock. I get the following stack trace: Exception in thread "main" org.jgroups.blocks.LockNotReleasedException: Lock cannot be unlocked. at org.jgroups.blocks.DistributedLockManager.unlock(DistributedLockManager.java:318) at org.jgroups.blocks.DistributedLockManager.unlock(DistributedLockManager.java:260) at com.overstock.distlock.examples.FailoverTest.doIt(FailoverTest.java:50) at com.overstock.distlock.examples.FailoverTest.main(FailoverTest.java:61) I am running version 2.4. Here's a sample program: package distlock.examples; import org.jgroups.JChannel; import org.jgroups.blocks.DistributedLockManager; import org.jgroups.blocks.LockNotGrantedException; import org.jgroups.blocks.VotingAdapter; public class FailoverTest { public static final String SERVER_PROTOCOL_STACK = "UDP(mcast_addr=228.3.11.76;mcast_port=12345;ip_ttl=1;" + "mcast_send_buf_size=150000;mcast_recv_buf_size=80000)" + ":PING(timeout=500;num_initial_members=1)" + ":FD" + ":VERIFY_SUSPECT(timeout=1500)" + ":pbcast.NAKACK(gc_lag=50;retransmit_timeout=300,600,1200,2400,4800)" + ":UNICAST(timeout=5000)" + ":pbcast.STABLE(desired_avg_gossip=200)" + ":FRAG(frag_size=4096)" + ":pbcast.GMS(join_timeout=5000;join_retry_timeout=1000;" + "shun=false;print_local_addr=false)" ; private void doIt() throws Exception { JChannel channel = new JChannel(SERVER_PROTOCOL_STACK); VotingAdapter adapter = new VotingAdapter(channel); channel.connect("cluster"); DistributedLockManager dlm = new DistributedLockManager(adapter, "Mgr"); String lockId = "theLock"; for (int i = 0; i < 40; i++) { while (true) { try { System.out.println("Trying to get lock."); dlm.lock(lockId, channel.getLocalAddress(), 10000); break; } catch (LockNotGrantedException ex) { System.out.println("Could not get lock."); } try { Thread.sleep(5000); } catch(InterruptedException ex) { } } System.out.println("Got lock, sleeping."); try { Thread.sleep(10000); } catch(InterruptedException ex) { } System.out.println("unlocking and sleeping."); dlm.unlock(lockId, channel.getLocalAddress()); try { Thread.sleep(5000); } catch(InterruptedException ex) { } } channel.close(); } public static void main(String[] args) throws Exception { System.setProperty("java.net.preferIPv4Stack", "true"); new FailoverTest().doIt(); } }