On Wed, Dec 16, 2009 at 03:48:39PM -0500, J. Bruce Fields wrote:
> 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.
Sorry, scratch the last sentence, I was overlooking the second
nfs4proc.c chunk above!
--b.
>
> --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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