Re: [PATCH 05/29] nfsd41: create_session cache hold client reference

["J. Bruce Fields" <bfields@fieldses.org>]

On Thu, Apr 23, 2009 at 12:42:44PM -0400, andros@netapp.com wrote:
> From: Andy Adamson <andros@netapp.com>
> 
> expire_client can be called on a confirmed or unconfirmed client while
> processing the create session operation and accessing the clientid slot.

I don't understand--isn't all that under the state lock for now?

--b.

> 
> Signed-off-by: Andy Adamson <andros@netapp.com>
> ---
>  fs/nfsd/nfs4state.c |   14 ++++++++++----
>  1 files changed, 10 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index a585a58..accad58 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -1355,6 +1355,7 @@ nfsd4_create_session(struct svc_rqst *rqstp,
>  	conf = find_confirmed_client(&cr_ses->clientid);
>  
>  	if (conf) {
> +		atomic_inc(&conf->cl_count);
>  		slot = &conf->cl_slot;
>  		status = check_slot_seqid(cr_ses->seqid, slot);
>  		if (status == nfserr_replay_cache) {
> @@ -1363,27 +1364,30 @@ nfsd4_create_session(struct svc_rqst *rqstp,
>  			cstate->status = nfserr_replay_clientid_cache;
>  			/* Return the cached reply status */
>  			status = nfsd4_replay_create_session(resp, slot);
> -			goto out;
> +			goto out_put;
>  		} else if (cr_ses->seqid != conf->cl_slot.sl_seqid + 1) {
>  			status = nfserr_seq_misordered;
>  			dprintk("Sequence misordered!\n");
>  			dprintk("Expected seqid= %d but got seqid= %d\n",
>  				slot->sl_seqid, cr_ses->seqid);
> -			goto out;
> +			goto out_put;
>  		}
>  		conf->cl_slot.sl_seqid++;
>  	} else if (unconf) {
> +		atomic_inc(&unconf->cl_count);
>  		slot = &unconf->cl_slot;
>  		status = check_slot_seqid(cr_ses->seqid, slot);
>  		if (status) {
>  			/* an unconfirmed replay returns misordered */
>  			status = nfserr_seq_misordered;
> -			goto out;
> +			conf = unconf; /* for put_nfs4_client */
> +			goto out_put;
>  		}
>  
>  		if (!same_creds(&unconf->cl_cred, &rqstp->rq_cred) ||
>  		    (ip_addr != unconf->cl_addr)) {
>  			status = nfserr_clid_inuse;
> +			conf = unconf; /* for put_nfs4_client */
>  			goto out_cache;
>  		}
>  
> @@ -1413,7 +1417,7 @@ nfsd4_create_session(struct svc_rqst *rqstp,
>  
>  	status = alloc_init_session(rqstp, conf, cr_ses);
>  	if (status)
> -		goto out;
> +		goto out_put;
>  
>  	memcpy(cr_ses->sessionid.data, conf->cl_sessionid.data,
>  	       NFS4_MAX_SESSIONID_LEN);
> @@ -1423,6 +1427,8 @@ out_cache:
>  	/* cache solo and embedded create sessions under the state lock */
>  	nfsd4_cache_create_session(cr_ses, slot, status);
>  
> +out_put:
> +	put_nfs4_client(conf);
>  out:
>  	nfs4_unlock_state();
>  	dprintk("%s returns %d\n", __func__, ntohl(status));
> -- 
> 1.5.4.3
>