OP_LOCK4: question about open_to_lock_owner4::lock_seqid

[J. Bruce Fields]

On Thu, Jul 03, 2008 at 09:41:15AM +0200, DENIEL Philippe wrote:
> Hi to all,
> 
> I need precisions about the way the lock_seqid field should be used in 
> OP_LOCK4 in the case of a new lock owner.
> The RFC3540 says:
> 
>       The locker argument specifies the lock_owner that is associated with
>        the LOCK request.  The locker4 structure is a switched union that
>        indicates whether the lock_owner is known to the server or if the
>        lock_owner is new to the server.  In the case that the lock_owner is
>        known to the server and has an established lock_seqid, the argument
>        is just the lock_owner and lock_seqid.  *In the case that the
>        lock_owner is not known to the server, the argument contains not only
>        the lock_owner and lock_seqid but also the open_stateid and
>        open_seqid.  *The new lock_owner case covers the very first lock done
>        by the lock_owner and offers a method to use the established state of
>        the open_stateid to transition to the use of the lock_owner.
> 
> It seems to me that a new lock owner will create a new state if lock is 
> successful with a brand new stateid. This stateid will contain a seqid of 0.
> the open_to_lock_owner4::lock_seqid field is the "desired" seqid for the 
> client, and since the lock owner is new, it can't be something else than 
> 0. So both client and server knowns this value is to be 0.
> So far, I am wondering about the use of this field in the case of a new 
> lock owner (if LOCK4arg::.locker.new_lock_owner == TRUE). Should I 
> ignore it ? Should I check it is 0 and return an error if
> the value is not 0 ? The test LOCK8c from newpynfs seems to take this 
> position: if LOCK4arg::.locker.new_lock_owner == TRUE and lock_seqid != 
> 0, NFS4ERR_BAD_SEQID should be returned.

My opinion is that clients should send 0, and servers should ignore it.
The linux server currently ignores it (and I run newpynfs with
noLOCK8C....).

This was discussed before (google for "relax new lock seqid check") but
I can't find a definitive conclusion.

--b.

> Is this the things to be implemented in my server ?
> 
>   Thanks in advance for your time and help
> 
>        Philippe
> 
> 
> 
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