[pnfs] Patch to fix ^C crash on mount

[Iyer, Rahul]

Hi guys,
This patch seems to have the side effect of eliminating the umount crash
as well. I'm still investigating as to why it worked. Either ways, the
client is now more stable than before. There are still a few issues:
- The open sequence counter seems to be encoded as is. So occasionally,
it winds up with a seqid of 1 and the server rejects it with
NFSERR_INVAL. 
- Read and write seem to update the lease value. This is not true in
NFSv4.1 IIRC. The current code does this and has the unfortunate effect
that if pNFS reads or writes run long (> lease time), then the client
would think the lease is up to date and not send SEQUENCE ops to the
MDS, resulting in NFSERR_BADSESSION/NFSERR_STALE_CLIENTID.
- The server code has a bug in EXCHANGE_ID which results in the long
strings of NFSERR_CLID_INUSE errors. The current code does:

        conf = find_confirmed_client_by_str(dname, strhashval);
        if (conf) {
                if (!cmp_creds(&conf->cl_cred, &rqstp->rq_cred) ||
(ip_addr != conf->cl_addr)) {
                        /* Client collision: send nfserr_clid_inuse */
                        goto out;
                }

                if (cmp_verf(&verf, &conf->cl_verifier)) {
			^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                        /* Client reboot: destroy old state */
                        expire_client(conf);
                        goto out_new;
                }
                /* router replay */
                goto out;
        }


In the highlighted line, it should be !cmp_verf because cmp_verf returns
true if the verifiers are the same.

I'll work on these and send out the patches.
Regards
Rahul




> -----Original Message-----
> From: William A. (Andy) Adamson [mailto:andros at citi.umich.edu] 
> Sent: Wednesday, July 18, 2007 9:47 AM
> To: Iyer, Rahul
> Cc: pnfs at linux-nfs.org
> Subject: Re: [pnfs] Patch to fix ^C crash on mount
> 
> ok. applied to 4.1-sessions branch and merged with master
> 
> -->Andy
> 
> 
> On 7/17/07, Iyer, Rahul <Rahul.Iyer at netapp.com> wrote:
> 
> 	Hi,
> 	If the mount hangs for some reason, and you hit ^C, the 
> client crashes as it tries to destroy a mempool and a  slab 
> that could be NULL. This patch check for the values before 
> destroying them.
> 	Regards
> 	Rahul
> 	 
> 
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