Re: RFC [patch 13/34] PID Virtualization Define new task_pid api

[ebiederm@xmission.com (Eric W. Biederman)]

Trond Myklebust <trond.myklebust@fys.uio.no> writes:

> 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.

Ok I though it might have been compared to equality someplace.

> nlm_find_lockowner() is used to define a unique identifier that is
> supposed to be sent to the server as the 'pid'.

Ok interesting.

All I know for certain was that with 2 pidspaces using the
same nfs mount I was confusing something, with regards to locking.


Eric