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

J. Bruce Fields
2009-04-23T23:28:25Z

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
>