nfsd: make openstateids hold references to their openowners

Change it so that only openstateids hold persistent references to
openowners. References can still be held by compounds in progress.

With this, we can get rid of NFS4_OO_NEW. It's possible that we
will create a new openowner in the process of doing the open, but
something later fails. In the meantime, another task could find
that openowner and start using it on a successful open. If that
occurs we don't necessarily want to tear it down, just put the
reference that the failing compound holds.
Signed-off-by: NJeff Layton <jlayton@primarydata.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfs4state.c

@@ -916,6 +916,8 @@ static void nfs4_free_ol_stateid(struct nfs4_stid *stid)
 	struct nfs4_ol_stateid *stp = openlockstateid(stid);
 
 	release_all_access(stp);
+	if (stp->st_stateowner)
+		nfs4_put_stateowner(stp->st_stateowner);
 	kmem_cache_free(stateid_slab, stid);
 }
 
@@ -928,8 +930,6 @@ static void nfs4_free_lock_stateid(struct nfs4_stid *stid)
 	file = find_any_file(stp->st_stid.sc_file);
 	if (file)
 		filp_close(file, (fl_owner_t)lo);
-	if (stp->st_stateowner)
-		nfs4_put_stateowner(stp->st_stateowner);
 	nfs4_free_ol_stateid(stid);
 }
 
@@ -1008,8 +1008,9 @@ static void release_last_closed_stateid(struct nfs4_openowner *oo)
 	struct nfs4_ol_stateid *s = oo->oo_last_closed_stid;
 
 	if (s) {
-		nfs4_put_stid(&s->st_stid);
+		list_del_init(&oo->oo_close_lru);
 		oo->oo_last_closed_stid = NULL;
+		nfs4_put_stid(&s->st_stid);
 	}
 }
 
@@ -1028,7 +1029,6 @@ static void release_openowner(struct nfs4_openowner *oo)
 {
 	unhash_openowner(oo);
 	release_openowner_stateids(oo);
-	list_del(&oo->oo_close_lru);
 	release_last_closed_stateid(oo);
 	nfs4_put_stateowner(&oo->oo_owner);
 }
@@ -1497,6 +1497,7 @@ destroy_client(struct nfs4_client *clp)
 	}
 	while (!list_empty(&clp->cl_openowners)) {
 		oo = list_entry(clp->cl_openowners.next, struct nfs4_openowner, oo_perclient);
+		atomic_inc(&oo->oo_owner.so_count);
 		release_openowner(oo);
 	}
 	nfsd4_shutdown_callback(clp);
@@ -3024,7 +3025,7 @@ alloc_init_open_stateowner(unsigned int strhashval, struct nfsd4_open *open,
 	oo->oo_owner.so_ops = &openowner_ops;
 	oo->oo_owner.so_is_open_owner = 1;
 	oo->oo_owner.so_seqid = open->op_seqid;
-	oo->oo_flags = NFS4_OO_NEW;
+	oo->oo_flags = 0;
 	if (nfsd4_has_session(cstate))
 		oo->oo_flags |= NFS4_OO_CONFIRMED;
 	oo->oo_time = 0;
@@ -3041,6 +3042,7 @@ static void init_open_stateid(struct nfs4_ol_stateid *stp, struct nfs4_file *fp,
 	stp->st_stid.sc_type = NFS4_OPEN_STID;
 	INIT_LIST_HEAD(&stp->st_locks);
 	stp->st_stateowner = &oo->oo_owner;
+	atomic_inc(&stp->st_stateowner->so_count);
 	get_nfs4_file(fp);
 	stp->st_stid.sc_file = fp;
 	stp->st_access_bmap = 0;
@@ -3054,13 +3056,27 @@ static void init_open_stateid(struct nfs4_ol_stateid *stp, struct nfs4_file *fp,
 	spin_unlock(&oo->oo_owner.so_client->cl_lock);
 }
 
+/*
+ * In the 4.0 case we need to keep the owners around a little while to handle
+ * CLOSE replay. We still do need to release any file access that is held by
+ * them before returning however.
+ */
 static void
-move_to_close_lru(struct nfs4_openowner *oo, struct net *net)
+move_to_close_lru(struct nfs4_ol_stateid *s, struct net *net)
 {
-	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
+	struct nfs4_openowner *oo = openowner(s->st_stateowner);
+	struct nfsd_net *nn = net_generic(s->st_stid.sc_client->net,
+						nfsd_net_id);
 
 	dprintk("NFSD: move_to_close_lru nfs4_openowner %p\n", oo);
 
+	release_all_access(s);
+	if (s->st_stid.sc_file) {
+		put_nfs4_file(s->st_stid.sc_file);
+		s->st_stid.sc_file = NULL;
+	}
+	release_last_closed_stateid(oo);
+	oo->oo_last_closed_stid = s;
 	list_move_tail(&oo->oo_close_lru, &nn->close_lru);
 	oo->oo_time = get_seconds();
 }
@@ -3091,6 +3107,7 @@ find_openstateowner_str(unsigned int hashval, struct nfsd4_open *open,
 			if ((bool)clp->cl_minorversion != sessions)
 				return NULL;
 			renew_client(oo->oo_owner.so_client);
+			atomic_inc(&oo->oo_owner.so_count);
 			return oo;
 		}
 	}
@@ -3887,19 +3904,10 @@ void nfsd4_cleanup_open_state(struct nfsd4_compound_state *cstate,
 			      struct nfsd4_open *open, __be32 status)
 {
 	if (open->op_openowner) {
-		struct nfs4_openowner *oo = open->op_openowner;
-
-		if (!list_empty(&oo->oo_owner.so_stateids))
-			list_del_init(&oo->oo_close_lru);
-		if (oo->oo_flags & NFS4_OO_NEW) {
-			if (status) {
-				release_openowner(oo);
-				open->op_openowner = NULL;
-			} else
-				oo->oo_flags &= ~NFS4_OO_NEW;
-		}
-		if (open->op_openowner)
-			nfsd4_cstate_assign_replay(cstate, &oo->oo_owner);
+		struct nfs4_stateowner *so = &open->op_openowner->oo_owner;
+
+		nfsd4_cstate_assign_replay(cstate, so);
+		nfs4_put_stateowner(so);
 	}
 	if (open->op_file)
 		nfsd4_free_file(open->op_file);
@@ -4015,7 +4023,7 @@ nfs4_laundromat(struct nfsd_net *nn)
 			new_timeo = min(new_timeo, t);
 			break;
 		}
-		release_openowner(oo);
+		release_last_closed_stateid(oo);
 	}
 	new_timeo = max_t(time_t, new_timeo, NFSD_LAUNDROMAT_MINTIMEOUT);
 	nfs4_unlock_state();
@@ -4580,31 +4588,14 @@ nfsd4_open_downgrade(struct svc_rqst *rqstp,
 static void nfsd4_close_open_stateid(struct nfs4_ol_stateid *s)
 {
 	struct nfs4_client *clp = s->st_stid.sc_client;
-	struct nfs4_openowner *oo = openowner(s->st_stateowner);
 
 	s->st_stid.sc_type = NFS4_CLOSED_STID;
 	unhash_open_stateid(s);
 
-	if (clp->cl_minorversion) {
-		if (list_empty(&oo->oo_owner.so_stateids))
-			release_openowner(oo);
+	if (clp->cl_minorversion)
 		nfs4_put_stid(&s->st_stid);
-	} else {
-		/*
-		 * In the 4.0 case we need to keep the owners around a
-		 * little while to handle CLOSE replay. We still do need
-		 * to release any file access that is held by them
-		 * before returning however.
-		 */
-		release_all_access(s);
-		if (s->st_stid.sc_file) {
-			put_nfs4_file(s->st_stid.sc_file);
-			s->st_stid.sc_file = NULL;
-		}
-		oo->oo_last_closed_stid = s;
-		if (list_empty(&oo->oo_owner.so_stateids))
-			move_to_close_lru(oo, clp->net);
-	}
+	else
+		move_to_close_lru(s, clp->net);
 }
 
 /*

fs/nfsd/state.h

@@ -367,7 +367,6 @@ struct nfs4_openowner {
 	struct nfs4_ol_stateid *oo_last_closed_stid;
 	time_t			oo_time; /* time of placement on so_close_lru */
 #define NFS4_OO_CONFIRMED   1
-#define NFS4_OO_NEW         4
 	unsigned char		oo_flags;
 };