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https://issues.apache.org/jira/browse/HDFS-3876?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Eli Collins updated HDFS-3876:
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    Attachment: hdfs-3876.txt
    
> NN should not RPC to self to find trash defaults (causes deadlock)
> ------------------------------------------------------------------
>
>                 Key: HDFS-3876
>                 URL: https://issues.apache.org/jira/browse/HDFS-3876
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: name-node
>    Affects Versions: 2.2.0-alpha
>            Reporter: Todd Lipcon
>            Assignee: Eli Collins
>            Priority: Blocker
>         Attachments: hdfs-3876.txt, hdfs-3876.txt, hdfs-3876.txt
>
>
> When transitioning a SBN to active, I ran into the following situation:
> - the TrashPolicy first gets loaded by an IPC Server Handler thread. The 
> {{initialize}} function then tries to make an RPC to the same node to find 
> out the defaults.
> - This is happening inside the NN write lock (since it's part of the active 
> initialization). Hence, all of the other handler threads are already blocked 
> waiting to get the NN lock.
> - Since no handler threads are free, the RPC blocks forever and the NN never 
> enters active state.
> We need to have a general policy that the NN should never make RPCs to itself 
> for any reason, due to potential for deadlocks like this.

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