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Subject: Re: RFC [patch 13/34] PID Virtualization Define new task_pid api
From: Trond Myklebust <trond.myklebust@fys.uio.no>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Arjan van de Ven <arjan@infradead.org>,
       Alan Cox <alan@lxorguk.ukuu.org.uk>,
       Hubertus Franke <frankeh@watson.ibm.com>,
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       Cedric Le Goater <clg@fr.ibm.com>
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On Wed, 2006-01-25 at 11:01 -0700, Eric W. Biederman wrote:
> fs/nfs/nfs3proc.c:nfs3_proc_create()
> For O_EXCL we have arg.verifier = current->pid.

Yes, but that does not result in any permanent state that would be tied
to the pid on the server. The verifier here is used only to ensure
idempotency of the exclusive create RPC call.

> fs/lockd/clntproc.c:nlmclnt_setlockargs()
> We have:	lock->oh.len  = sprintf(req->a_owner, "%d@%s",
> 					current->pid, system_utsname.nodename);
> 
> I think this is the fcntl() case.
> I would suggest fl_pid might have something to do with it 
> but that is part flock based locking.

That name is not interpreted by the NLM server. It is, AFAIK, only used
for debugging purposes.
nlm_find_lockowner() is used to define a unique identifier that is
supposed to be sent to the server as the 'pid'.

Cheers,
  Trond