nfsd4: implement SEQ4_STATUS_RECALLABLE_STATE_REVOKED

A 4.1 server must notify a client that has had any state revoked using
the SEQ4_STATUS_RECALLABLE_STATE_REVOKED flag.  The client can figure
out exactly which state is the problem using CHECK_STATEID and then free
it using FREE_STATEID.  The status flag will be unset once all such
revoked stateids are freed.

Our server's only recallable state is delegations.  So we keep with each
4.1 client a list of delegations that have timed out and been recalled,
but haven't yet been freed by FREE_STATEID.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfs4state.c

@@ -445,7 +445,6 @@ static void unhash_stid(struct nfs4_stid *s)
 static void
 unhash_delegation(struct nfs4_delegation *dp)
 {
-	unhash_stid(&dp->dl_stid);
 	list_del_init(&dp->dl_perclnt);
 	spin_lock(&recall_lock);
 	list_del_init(&dp->dl_perfile);
@@ -454,10 +453,37 @@ unhash_delegation(struct nfs4_delegation *dp)
 	nfs4_put_deleg_lease(dp->dl_file);
 	put_nfs4_file(dp->dl_file);
 	dp->dl_file = NULL;
+}
+
+
+
+static void destroy_revoked_delegation(struct nfs4_delegation *dp)
+{
+	list_del_init(&dp->dl_recall_lru);
 	remove_stid(&dp->dl_stid);
 	nfs4_put_delegation(dp);
 }
 
+static void destroy_delegation(struct nfs4_delegation *dp)
+{
+	unhash_delegation(dp);
+	remove_stid(&dp->dl_stid);
+	nfs4_put_delegation(dp);
+}
+
+static void revoke_delegation(struct nfs4_delegation *dp)
+{
+	struct nfs4_client *clp = dp->dl_stid.sc_client;
+
+	if (clp->cl_minorversion == 0)
+		destroy_delegation(dp);
+	else {
+		unhash_delegation(dp);
+		dp->dl_stid.sc_type = NFS4_REVOKED_DELEG_STID;
+		list_add(&dp->dl_recall_lru, &clp->cl_revoked);
+	}
+}
+
 /* 
  * SETCLIENTID state 
  */
@@ -1114,7 +1140,7 @@ destroy_client(struct nfs4_client *clp)
 	spin_unlock(&recall_lock);
 	while (!list_empty(&reaplist)) {
 		dp = list_entry(reaplist.next, struct nfs4_delegation, dl_recall_lru);
-		unhash_delegation(dp);
+		destroy_delegation(dp);
 	}
 	while (!list_empty(&clp->cl_openowners)) {
 		oo = list_entry(clp->cl_openowners.next, struct nfs4_openowner, oo_perclient);
@@ -1310,6 +1336,7 @@ static struct nfs4_client *create_client(struct xdr_netobj name,
 	INIT_LIST_HEAD(&clp->cl_delegations);
 	INIT_LIST_HEAD(&clp->cl_lru);
 	INIT_LIST_HEAD(&clp->cl_callbacks);
+	INIT_LIST_HEAD(&clp->cl_revoked);
 	spin_lock_init(&clp->cl_lock);
 	nfsd4_init_callback(&clp->cl_cb_null);
 	clp->cl_time = get_seconds();
@@ -2171,6 +2198,8 @@ out:
 	default:
 		seq->status_flags = 0;
 	}
+	if (!list_empty(&clp->cl_revoked))
+		seq->status_flags |= SEQ4_STATUS_RECALLABLE_STATE_REVOKED;
 out_no_session:
 	kfree(conn);
 	spin_unlock(&nn->client_lock);
@@ -3297,7 +3326,7 @@ nfs4_laundromat(struct nfsd_net *nn)
 	spin_unlock(&recall_lock);
 	list_for_each_safe(pos, next, &reaplist) {
 		dp = list_entry (pos, struct nfs4_delegation, dl_recall_lru);
-		unhash_delegation(dp);
+		revoke_delegation(dp);
 	}
 	test_val = nn->nfsd4_lease;
 	list_for_each_safe(pos, next, &nn->close_lru) {
@@ -3459,6 +3488,8 @@ static __be32 nfsd4_validate_stateid(struct nfs4_client *cl, stateid_t *stateid)
 	switch (s->sc_type) {
 	case NFS4_DELEG_STID:
 		return nfs_ok;
+	case NFS4_REVOKED_DELEG_STID:
+		return nfserr_deleg_revoked;
 	case NFS4_OPEN_STID:
 	case NFS4_LOCK_STID:
 		ols = openlockstateid(s);
@@ -3602,6 +3633,7 @@ nfsd4_free_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 {
 	stateid_t *stateid = &free_stateid->fr_stateid;
 	struct nfs4_stid *s;
+	struct nfs4_delegation *dp;
 	struct nfs4_client *cl = cstate->session->se_client;
 	__be32 ret = nfserr_bad_stateid;
 
@@ -3623,6 +3655,11 @@ nfsd4_free_stateid(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 		else
 			ret = nfserr_locks_held;
 		break;
+	case NFS4_REVOKED_DELEG_STID:
+		dp = delegstateid(s);
+		destroy_revoked_delegation(dp);
+		ret = nfs_ok;
+		break;
 	default:
 		ret = nfserr_bad_stateid;
 	}
@@ -3647,10 +3684,12 @@ static __be32 nfs4_seqid_op_checks(struct nfsd4_compound_state *cstate, stateid_
 	status = nfsd4_check_seqid(cstate, sop, seqid);
 	if (status)
 		return status;
-	if (stp->st_stid.sc_type == NFS4_CLOSED_STID)
+	if (stp->st_stid.sc_type == NFS4_CLOSED_STID
+		|| stp->st_stid.sc_type == NFS4_REVOKED_DELEG_STID)
 		/*
 		 * "Closed" stateid's exist *only* to return
-		 * nfserr_replay_me from the previous step.
+		 * nfserr_replay_me from the previous step, and
+		 * revoked delegations are kept only for free_stateid.
 		 */
 		return nfserr_bad_stateid;
 	status = check_stateid_generation(stateid, &stp->st_stid.sc_stateid, nfsd4_has_session(cstate));
@@ -3913,7 +3952,7 @@ nfsd4_delegreturn(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	if (status)
 		goto out;
 
-	unhash_delegation(dp);
+	destroy_delegation(dp);
 out:
 	nfs4_unlock_state();
 
@@ -4763,7 +4802,7 @@ u64 nfsd_forget_client_delegations(struct nfs4_client *clp, u64 max)
 	spin_unlock(&recall_lock);
 
 	list_for_each_entry_safe(dp, next, &victims, dl_recall_lru)
-		unhash_delegation(dp);
+		revoke_delegation(dp);
 
 	return count;
 }
@@ -5018,7 +5057,7 @@ nfs4_state_shutdown_net(struct net *net)
 	spin_unlock(&recall_lock);
 	list_for_each_safe(pos, next, &reaplist) {
 		dp = list_entry (pos, struct nfs4_delegation, dl_recall_lru);
-		unhash_delegation(dp);
+		destroy_delegation(dp);
 	}
 
 	nfsd4_client_tracking_exit(net);

fs/nfsd/state.h

@@ -79,6 +79,8 @@ struct nfs4_stid {
 #define NFS4_DELEG_STID 4
 /* For an open stateid kept around *only* to process close replays: */
 #define NFS4_CLOSED_STID 8
+/* For a deleg stateid kept around only to process free_stateid's: */
+#define NFS4_REVOKED_DELEG_STID 16
 	unsigned char sc_type;
 	stateid_t sc_stateid;
 	struct nfs4_client *sc_client;
@@ -238,6 +240,7 @@ struct nfs4_client {
 	struct list_head	cl_openowners;
 	struct idr		cl_stateids;	/* stateid lookup */
 	struct list_head	cl_delegations;
+	struct list_head	cl_revoked;	/* unacknowledged, revoked 4.1 state */
 	struct list_head        cl_lru;         /* tail queue */
 	struct xdr_netobj	cl_name; 	/* id generated by client */
 	nfs4_verifier		cl_verifier; 	/* generated by client */