NFSv4.1: Don't loop forever in nfs4_proc_create_session

If a server for some reason keeps sending NFS4ERR_DELAY errors, we can end
up looping forever inside nfs4_proc_create_session, and so the usual
mechanisms for detecting if the nfs_client is dead don't work.

Fix this by ensuring that we loop inside the nfs4_state_manager thread
instead.

Signed-off-by: Trond Myklebust <[e-mail]>

fs/nfs/nfs4_fs.h

···
 	NFS4CLNT_LAYOUTRECALL,
 	NFS4CLNT_SESSION_RESET,
 	NFS4CLNT_RECALL_SLOT,
+	NFS4CLNT_LEASE_CONFIRM,
 };
 
 enum nfs4_session_state {

fs/nfs/nfs4proc.c

···
 		status = rpc_call_sync(clp->cl_rpcclient, &msg, 0);
 		if (status != -NFS4ERR_CLID_INUSE)
 			break;
-		if (signalled())
+		if (loop != 0) {
+			++clp->cl_id_uniquifier;
 			break;
-		if (loop++ & 1)
-			ssleep(clp->cl_lease_time / HZ + 1);
-		else
-			if (++clp->cl_id_uniquifier == 0)
-				break;
+		}
+		++loop;
+		ssleep(clp->cl_lease_time / HZ + 1);
 	}
 	return status;
 }
 
-static int _nfs4_proc_setclientid_confirm(struct nfs_client *clp,
+int nfs4_proc_setclientid_confirm(struct nfs_client *clp,
 		struct nfs4_setclientid_res *arg,
 		struct rpc_cred *cred)
 {
···
 		spin_unlock(&clp->cl_lock);
 	}
 	return status;
-}
-
-int nfs4_proc_setclientid_confirm(struct nfs_client *clp,
-		struct nfs4_setclientid_res *arg,
-		struct rpc_cred *cred)
-{
-	long timeout = 0;
-	int err;
-	do {
-		err = _nfs4_proc_setclientid_confirm(clp, arg, cred);
-		switch (err) {
-			case 0:
-				return err;
-			case -NFS4ERR_RESOURCE:
-				/* The IBM lawyers misread another document! */
-			case -NFS4ERR_DELAY:
-				err = nfs4_delay(clp->cl_rpcclient, &timeout);
-		}
-	} while (err == 0);
-	return err;
 }
 
 struct nfs4_delegreturndata {
···
 	int status;
 	unsigned *ptr;
 	struct nfs4_session *session = clp->cl_session;
-	long timeout = 0;
-	int err;
 
 	dprintk("--> %s clp=%p session=%p\n", __func__, clp, session);
 
-	do {
-		status = _nfs4_proc_create_session(clp);
-		if (status == -NFS4ERR_DELAY) {
-			err = nfs4_delay(clp->cl_rpcclient, &timeout);
-			if (err)
-				status = err;
-		}
-	} while (status == -NFS4ERR_DELAY);
-
+	status = _nfs4_proc_create_session(clp);
 	if (status)
 		goto out;
 

fs/nfs/nfs4state.c

···
 
 int nfs4_init_clientid(struct nfs_client *clp, struct rpc_cred *cred)
 {
-	struct nfs4_setclientid_res clid;
+	struct nfs4_setclientid_res clid = {
+		.clientid = clp->cl_clientid,
+		.confirm = clp->cl_confirm,
+	};
 	unsigned short port;
 	int status;
 
+	if (test_bit(NFS4CLNT_LEASE_CONFIRM, &clp->cl_state))
+		goto do_confirm;
 	port = nfs_callback_tcpport;
 	if (clp->cl_addr.ss_family == AF_INET6)
 		port = nfs_callback_tcpport6;
···
 	status = nfs4_proc_setclientid(clp, NFS4_CALLBACK, port, cred, &clid);
 	if (status != 0)
 		goto out;
+	clp->cl_clientid = clid.clientid;
+	clp->cl_confirm = clid.confirm;
+	set_bit(NFS4CLNT_LEASE_CONFIRM, &clp->cl_state);
+do_confirm:
 	status = nfs4_proc_setclientid_confirm(clp, &clid, cred);
 	if (status != 0)
 		goto out;
-	clp->cl_clientid = clid.clientid;
+	clear_bit(NFS4CLNT_LEASE_CONFIRM, &clp->cl_state);
 	nfs4_schedule_state_renewal(clp);
 out:
 	return status;
···
 {
 	int status;
 
+	if (test_bit(NFS4CLNT_LEASE_CONFIRM, &clp->cl_state))
+		goto do_confirm;
 	nfs4_begin_drain_session(clp);
 	status = nfs4_proc_exchange_id(clp, cred);
 	if (status != 0)
 		goto out;
+	set_bit(NFS4CLNT_LEASE_CONFIRM, &clp->cl_state);
+do_confirm:
 	status = nfs4_proc_create_session(clp);
 	if (status != 0)
 		goto out;
+	clear_bit(NFS4CLNT_LEASE_CONFIRM, &clp->cl_state);
 	nfs41_setup_state_renewal(clp);
 	nfs_mark_client_ready(clp, NFS_CS_READY);
 out:
···
  */
 static void nfs4_set_lease_expired(struct nfs_client *clp, int status)
 {
-	if (nfs4_has_session(clp)) {
-		switch (status) {
-		case -NFS4ERR_DELAY:
-		case -NFS4ERR_CLID_INUSE:
-		case -EAGAIN:
-			break;
+	switch (status) {
+	case -NFS4ERR_CLID_INUSE:
+	case -NFS4ERR_STALE_CLIENTID:
+		clear_bit(NFS4CLNT_LEASE_CONFIRM, &clp->cl_state);
+		break;
+	case -NFS4ERR_DELAY:
+	case -EAGAIN:
+		ssleep(1);
+		break;
 
-		case -EKEYEXPIRED:
-			nfs4_warn_keyexpired(clp->cl_hostname);
-		case -NFS4ERR_NOT_SAME: /* FixMe: implement recovery
-					 * in nfs4_exchange_id */
-		default:
-			return;
-		}
+	case -EKEYEXPIRED:
+		nfs4_warn_keyexpired(clp->cl_hostname);
+	case -NFS4ERR_NOT_SAME: /* FixMe: implement recovery
+				 * in nfs4_exchange_id */
+	default:
+		return;
 	}
 	set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
 }

include/linux/nfs_fs_sb.h

···
 
 #ifdef CONFIG_NFS_V4
 	u64			cl_clientid;	/* constant */
+	nfs4_verifier		cl_confirm;	/* Clientid verifier */
 	unsigned long		cl_state;
 
 	spinlock_t		cl_lock;