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  1. Lustre
  2. LU-6582

Wireshark fails to parse LDLM_ENQUEUE RPC - likely for layout lock

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Details

    • Bug
    • Resolution: Fixed
    • Minor
    • Lustre 2.10.0
    • None
    • 3
    • 9223372036854775807

    Description

      It looks to me like there is a least one bug in the Wireshark parsing. What I see is an LDLM_ENQUEUE that I think is wanting to do RQF_LDLM_INTENT_GETXATTR in order to establish a layout lock on the MDT. Some of the structures/fields appear to be missing in the parsed output,
      the LDLM_ENQUEUE request appears in the output with ³LustreBUG² in place
      of ³LUSTRE², and the LDLM_ENQUEUE reply says ³malformed packet².

      A simple experiment that will replicate this behavior is to run the shell command 'touch -c file'. I do it from a client that has not previously visited the file or directory, so I know that nothing is cached. I also have the file precreated from a separate client, so that there really is a file to 'touch'. The '-c' suppresses any file create/file open that otherwise might be attempted, so you just get the simple 'setattr' behaviour. After the resulting MDS_REINT:REINT_SETATTR RPCs are exchanged, and before the subsequent MDS_GETXATTR:trusted.lov that get the actual layout, there is an LDLM_ENQUEUE exchanged that exhibits the problem. It's a good guess that it is trying to get a layout lock. The actual activities appear to be working fine, it is just the Wireshark parsing that appears to be a problem.

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              utopiabound Nathaniel Clark
              uselton Andrew Uselton (Inactive)
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