On Wed, Dec 16, 2009 at 07:41:12PM +0200, Benny Halevy wrote:
> Mark the nfs4_client for renew on operations holding a stateid (or nfs41
> OP_SEQUENCE).
> Do the actual lru list update when the compound processing is complete.
> This will prevents the client from being expired by the laundromat while
> the compound is in progress.
>
> Signed-off-by: Benny Halevy <bhalevy@xxxxxxxxxxx>
> ---
> fs/nfsd/nfs4proc.c | 5 +++++
> fs/nfsd/nfs4state.c | 39 +++++++++++++++++++++++++++++++++++----
> fs/nfsd/state.h | 1 +
> fs/nfsd/xdr4.h | 1 +
> 4 files changed, 42 insertions(+), 4 deletions(-)
>
> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
> index 37514c4..a8e9731 100644
> --- a/fs/nfsd/nfs4proc.c
> +++ b/fs/nfsd/nfs4proc.c
> @@ -1010,6 +1010,7 @@ nfsd4_proc_compound(struct svc_rqst *rqstp,
> resp->opcnt = 0;
> resp->rqstp = rqstp;
> resp->cstate.minorversion = args->minorversion;
> + resp->cstate.renew_client = NULL;
> resp->cstate.replay_owner = NULL;
> fh_init(&resp->cstate.current_fh, NFS4_FHSIZE);
> fh_init(&resp->cstate.save_fh, NFS4_FHSIZE);
> @@ -1114,6 +1115,10 @@ encode_op:
> fh_put(&resp->cstate.current_fh);
> fh_put(&resp->cstate.save_fh);
> BUG_ON(resp->cstate.replay_owner);
> + if (resp->cstate.renew_client) {
> + renew_client(resp->cstate.renew_client);
> + put_nfs4_client(resp->cstate.renew_client);
> + }
> out:
> nfsd4_release_compoundargs(args);
> /* Reset deferral mechanism for RPC deferrals */
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index c456551..16ccab3 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -634,8 +634,39 @@ free_session(struct kref *kref)
> }
>
> static inline void
> +mark_client_for_renew(struct nfsd4_compound_state *cstate,
> + struct nfs4_client *clp)
> +{
> + int old_state = atomic_cmpxchg(&clp->cl_state, CL_STATE_NORMAL,
> + CL_STATE_RENEW);
> +
> + if (old_state != CL_STATE_EXPIRED) {
> + cstate->renew_client = clp;
> + get_nfs4_client(clp);
If cstate->renew_client is already set, then we may leak a reference
count here, right?
Also: at least in the v4 case, I don't think there's anything preventing
cstate->renew_client being already set to a different client. (With
sessions hopefully that's not possible.)
This patch doesn't appear to stand alone as it removes the client
renewals without yet replacing them by anything.
--b.
> + }
> +
> + dprintk("%s: client (clientid %08x/%08x) %s\n",
> + __func__,
> + clp->cl_clientid.cl_boot,
> + clp->cl_clientid.cl_id,
> + old_state == CL_STATE_EXPIRED ? "already expired" :
> + "marked for renew");
> +}
> +
> +void
> renew_client(struct nfs4_client *clp)
> {
> + int old_state = atomic_cmpxchg(&clp->cl_state, CL_STATE_RENEW,
> + CL_STATE_NORMAL);
> +
> + if (old_state == CL_STATE_EXPIRED) {
> + dprintk("%s: client (clientid %08x/%08x) already expired\n",
> + __func__,
> + clp->cl_clientid.cl_boot,
> + clp->cl_clientid.cl_id);
> + return;
> + }
> +
> /*
> * Move client to the end to the LRU list.
> */
> @@ -1471,7 +1502,7 @@ out:
> /* Renew the clientid on success and on replay */
> if (cstate->session) {
> nfs4_lock_state();
> - renew_client(session->se_client);
> + mark_client_for_renew(cstate, session->se_client);
> nfs4_unlock_state();
> }
> dprintk("%s: return %d\n", __func__, ntohl(status));
> @@ -2830,7 +2861,7 @@ nfs4_preprocess_stateid_op(struct nfsd4_compound_state *cstate,
> status = nfs4_check_delegmode(dp, flags);
> if (status)
> goto out;
> - renew_client(dp->dl_client);
> + mark_client_for_renew(cstate, dp->dl_client);
> if (filpp)
> *filpp = dp->dl_vfs_file;
> } else { /* open or lock stateid */
> @@ -2850,7 +2881,7 @@ nfs4_preprocess_stateid_op(struct nfsd4_compound_state *cstate,
> status = nfs4_check_openmode(stp, flags);
> if (status)
> goto out;
> - renew_client(stp->st_stateowner->so_client);
> + mark_client_for_renew(cstate, stp->st_stateowner->so_client);
> if (filpp)
> *filpp = stp->st_vfs_file;
> }
> @@ -2970,7 +3001,7 @@ nfs4_preprocess_seqid_op(struct nfsd4_compound_state *cstate, u32 seqid,
> status = check_stateid_generation(stateid, &stp->st_stateid, flags);
> if (status)
> return status;
> - renew_client(sop->so_client);
> + mark_client_for_renew(cstate, sop->so_client);
> return nfs_ok;
>
> check_replay:
> diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
> index 21109d4..b684c84 100644
> --- a/fs/nfsd/state.h
> +++ b/fs/nfsd/state.h
> @@ -385,6 +385,7 @@ extern void nfs4_lock_state(void);
> extern void nfs4_unlock_state(void);
> extern int nfs4_in_grace(void);
> extern __be32 nfs4_check_open_reclaim(clientid_t *clid);
> +extern void renew_client(struct nfs4_client *);
> extern void get_nfs4_client(struct nfs4_client *);
> extern void put_nfs4_client(struct nfs4_client *clp);
> extern void nfs4_free_stateowner(struct kref *kref);
> diff --git a/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h
> index efa3377..e48d5c7 100644
> --- a/fs/nfsd/xdr4.h
> +++ b/fs/nfsd/xdr4.h
> @@ -46,6 +46,7 @@
> struct nfsd4_compound_state {
> struct svc_fh current_fh;
> struct svc_fh save_fh;
> + struct nfs4_client *renew_client;
> struct nfs4_stateowner *replay_owner;
> /* For sessions DRC */
> struct nfsd4_session *session;
> --
> 1.6.5.1
>
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