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From "Uma Maheswara Rao G (Commented) (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HDFS-1241) Possible deadlock between LeaseManager and FSDirectory
Date Tue, 29 Nov 2011 11:01:40 GMT

    [ https://issues.apache.org/jira/browse/HDFS-1241?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13159192#comment-13159192
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Uma Maheswara Rao G commented on HDFS-1241:
-------------------------------------------

Just having a quick look at this,
 
LeaseManager.findPath() will be invoked by committBlockSynchronization,completeFile, updatePipeline,
they are already aquired lock on fsNameSystem.

FSDirectory.unprotectedDelete will be invoked from FSNameSystem#delete api, whihc is already
aquired the lock on fsnamesystem.
One more palce is loadEditsRecords, which should be at start.
I think dead lock may not be possible here.
Do you see any other problem here? am i missing some thing here?

Thanks
Uma



                
> Possible deadlock between LeaseManager and FSDirectory
> ------------------------------------------------------
>
>                 Key: HDFS-1241
>                 URL: https://issues.apache.org/jira/browse/HDFS-1241
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: name-node
>    Affects Versions: 0.20.2, 0.21.0
>            Reporter: Todd Lipcon
>         Attachments: leasemanager.png
>
>
> LeaseManager.findPath() locks LeaseManager, then FSDirectory by caling getFileINode.
FSDirectory.unprotectedDelete locks itself and then calls LeaseManager.removeLeaseWithPrefixPath.
This cycle could deadlock.

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