[pnfs] [PATCH 9/9] pnfs client prevent race in sequence slot

[Trond Myklebust]

On Thu, 2007-09-27 at 15:12 -0400, Trond Myklebust wrote:
> On Thu, 2007-09-27 at 15:00 -0400, William A. (Andy) Adamson wrote:
> > 
> > 
> > On 9/26/07, Trond Myklebust <trond.myklebust at fys.uio.no> wrote:
> >         If we have to interrupt an RPC call, then we immediately fire
> >         off an
> >         asynchronous RPC call with a single SEQUENCE call that uses
> >         the _same_
> >         sa_sequence id as the synchronous RPC call that was cancelled
> >         (and drops 
> >         all the other arguments).
> > 
> > ok. but can't we get around sending yet another rpc by looking at what
> > the server has already sent (or not)?  we do have all the information.
> 
> I don't understand. If you have a reply, then you're not interrupting an
> RPC call, however the fact that you don't have a reply means nothing:
> assuming that an RPC call was actually sent by the client then the
> server may or may not have received it (we just don't know until we have
> a reply).

Oh... I think I see your point. Are you perhaps suggesting that we just
look for the NFS4ERR_SEQ_MISORDERED reply, and use that as to indicate
that the server didn't see our previous RPC call on that slot?
That might work too.

Trond