trying to read configuration in hdfs write path might result in deadlock
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                 Key: HDFS-2081
                 URL: https://issues.apache.org/jira/browse/HDFS-2081
             Project: Hadoop HDFS
          Issue Type: Bug
         Environment: MR-279 branch. This is specific to yarn since yarn tries 
to write the configuration file to hdfs while holding the lock of the 
configuration file.
            Reporter: John George
            Assignee: John George


While trying to run yarn with 1024 block size, it looks as though the 
dfsclients are hung waiting to write to DN. The reason is because yarn golds 
the configuration file lock and tries to write to hdfs which in turn tries to 
read from the configuration which requires the same lock.

The temporary fix is to make sure that dfsclient threads dont read the config 
in its write path. There might be better long term solutions like read/write 
locks and this needs to be investigated in another JIRA.

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