Date: Tue, 2 Aug 2011 08:56:08 -0400
From: Jim Rees <rees@umich.edu>
To: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Peng Tao <bergwolf@gmail.com>,
        "Adamson, Andy" <William.Adamson@netapp.com>,
        Christoph Hellwig <hch@infradead.org>, linux-nfs@vger.kernel.org,
        peter honeyman <honey@citi.umich.edu>
Subject: Re: [PATCH v4 00/27] add block layout driver to pnfs client
Message-ID: <20110802125608.GA1362@merit.edu>
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 <1312233006.23392.17.camel@lade.trondhjem.org>
 <1312238117.23392.19.camel@lade.trondhjem.org>
 <20110802022144.GA18157@merit.edu>
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Trond Myklebust wrote:

  Any idea which file that thread is deleting, and why that might be
  hanging?

The test is a copy of the part of the mount command that writes /etc/mtab.
So it's doing some sequence of link, write, flock.  It does this thousands
of times, much of it in parallel.  I'll get a trace of a single instance of
this so we can see what the actual syscalls are.  I'll also see about
turning on the mutex debug.  Give me a couple of hours.

If you want to look at the source code for the test, clone this:
git://oss.sgi.com/xfs/cmds/xfstests

and it's in src/t_mtab.c.  It's driven by the "089" script.