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Bela Ban updated JGRP-2234:
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Fix Version/s: 4.0.10
(was: 4.0.9)
Unlocked locks stay locked forever
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Key: JGRP-2234
URL:
https://issues.jboss.org/browse/JGRP-2234
Project: JGroups
Issue Type: Bug
Reporter: Bram Klein Gunnewiek
Assignee: Bela Ban
Fix For: 4.0.10
Attachments: ClusterSplitLockTest.java, jg_clusterlock_output_testfail.txt
As discussed in the mailing list we have issues where locks from the central lock
protocol stay locked forever when the coordinator of the cluster disconnects. We can
reproduce this with the attached ClusterSplitLockTest.java. Its a race condition and we
need to run the test a lot of times (sometimes > 20) before we encounter a failure.
What we think is happening:
In a three node cluster (node A, B and C where node A is the coordinator) unlock requests
from B and/or C can be missed when node A leaves and B and/or C don't have the new
view installed yet. When, for example, node B takes over coordination it creates the lock
table based on the back-ups. Lets say node C has locked the lock with name
'lockX'. Node C performs an unlock of 'lockX' just after node A
(gracefully) leaves and sends the unlock request to node A since node C doesn't have
the correct view installed yet. Node B has and recreated the lock table where
'lockX' is locked by Node C. Node C doesn't resend the unlock request so
'lockX' gets locked forever.
Attached is the testng test we wrote and the output of a test failure.