NFS bugfixes for Linux 3.7

- Fix the NFSv2/v3 kernel statd protocol, which broke due to net namespace
   related changes.
 - Fix a number of races in the SUNRPC TCP disconnect/reconnect code.
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Merge tag 'nfs-for-3.7-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull NFS bugfixes from Trond Myklebust:

 - Fix the NFSv2/v3 kernel statd protocol, which broke due to net
   namespace related changes.

 - Fix a number of races in the SUNRPC TCP disconnect/reconnect code.

* tag 'nfs-for-3.7-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  LOCKD: Clear ln->nsm_clnt only when ln->nsm_users is zero
  LOCKD: fix races in nsm_client_get
  SUNRPC: Get rid of the xs_error_report socket callback
  SUNRPC: Prevent races in xs_abort_connection()
  Revert "SUNRPC: Ensure we close the socket on EPIPE errors too..."
  SUNRPC: Clear the connect flag when socket state is TCP_CLOSE_WAIT

fs/lockd/mon.c

@@ -85,29 +85,38 @@ static struct rpc_clnt *nsm_create(struct net *net)
 	return rpc_create(&args);
 }
 
+static struct rpc_clnt *nsm_client_set(struct lockd_net *ln,
+		struct rpc_clnt *clnt)
+{
+	spin_lock(&ln->nsm_clnt_lock);
+	if (ln->nsm_users == 0) {
+		if (clnt == NULL)
+			goto out;
+		ln->nsm_clnt = clnt;
+	}
+	clnt = ln->nsm_clnt;
+	ln->nsm_users++;
+out:
+	spin_unlock(&ln->nsm_clnt_lock);
+	return clnt;
+}
+
 static struct rpc_clnt *nsm_client_get(struct net *net)
 {
-	static DEFINE_MUTEX(nsm_create_mutex);
+	struct rpc_clnt	*clnt, *new;
-	struct rpc_clnt	*clnt;
 	struct lockd_net *ln = net_generic(net, lockd_net_id);
 
-	spin_lock(&ln->nsm_clnt_lock);
+	clnt = nsm_client_set(ln, NULL);
-	if (ln->nsm_users) {
+	if (clnt != NULL)
-		ln->nsm_users++;
-		clnt = ln->nsm_clnt;
-		spin_unlock(&ln->nsm_clnt_lock);
 		goto out;
-	}
-	spin_unlock(&ln->nsm_clnt_lock);
 
-	mutex_lock(&nsm_create_mutex);
+	clnt = new = nsm_create(net);
-	clnt = nsm_create(net);
+	if (IS_ERR(clnt))
-	if (!IS_ERR(clnt)) {
+		goto out;
-		ln->nsm_clnt = clnt;
+
-		smp_wmb();
+	clnt = nsm_client_set(ln, new);
-		ln->nsm_users = 1;
+	if (clnt != new)
-	}
+		rpc_shutdown_client(new);
-	mutex_unlock(&nsm_create_mutex);
 out:
 	return clnt;
 }
@@ -115,18 +124,16 @@ out:
 static void nsm_client_put(struct net *net)
 {
 	struct lockd_net *ln = net_generic(net, lockd_net_id);
-	struct rpc_clnt	*clnt = ln->nsm_clnt;
+	struct rpc_clnt	*clnt = NULL;
-	int shutdown = 0;
 
 	spin_lock(&ln->nsm_clnt_lock);
-	if (ln->nsm_users) {
+	ln->nsm_users--;
-		if (--ln->nsm_users)
+	if (ln->nsm_users == 0) {
-			ln->nsm_clnt = NULL;
+		clnt = ln->nsm_clnt;
-		shutdown = !ln->nsm_users;
+		ln->nsm_clnt = NULL;
 	}
 	spin_unlock(&ln->nsm_clnt_lock);
-
+	if (clnt != NULL)
-	if (shutdown)
 		rpc_shutdown_client(clnt);
 }
 

net/sunrpc/xprtsock.c

@@ -254,7 +254,6 @@ struct sock_xprt {
 	void			(*old_data_ready)(struct sock *, int);
 	void			(*old_state_change)(struct sock *);
 	void			(*old_write_space)(struct sock *);
-	void			(*old_error_report)(struct sock *);
 };
 
 /*
@@ -737,10 +736,10 @@ static int xs_tcp_send_request(struct rpc_task *task)
 		dprintk("RPC:       sendmsg returned unrecognized error %d\n",
 			-status);
 	case -ECONNRESET:
-	case -EPIPE:
 		xs_tcp_shutdown(xprt);
 	case -ECONNREFUSED:
 	case -ENOTCONN:
+	case -EPIPE:
 		clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
 	}
 
@@ -781,7 +780,6 @@ static void xs_save_old_callbacks(struct sock_xprt *transport, struct sock *sk)
 	transport->old_data_ready = sk->sk_data_ready;
 	transport->old_state_change = sk->sk_state_change;
 	transport->old_write_space = sk->sk_write_space;
-	transport->old_error_report = sk->sk_error_report;
 }
 
 static void xs_restore_old_callbacks(struct sock_xprt *transport, struct sock *sk)
@@ -789,7 +787,6 @@ static void xs_restore_old_callbacks(struct sock_xprt *transport, struct sock *s
 	sk->sk_data_ready = transport->old_data_ready;
 	sk->sk_state_change = transport->old_state_change;
 	sk->sk_write_space = transport->old_write_space;
-	sk->sk_error_report = transport->old_error_report;
 }
 
 static void xs_reset_transport(struct sock_xprt *transport)
@@ -1453,7 +1450,7 @@ static void xs_tcp_cancel_linger_timeout(struct rpc_xprt *xprt)
 	xprt_clear_connecting(xprt);
 }
 
-static void xs_sock_mark_closed(struct rpc_xprt *xprt)
+static void xs_sock_reset_connection_flags(struct rpc_xprt *xprt)
 {
 	smp_mb__before_clear_bit();
 	clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
@@ -1461,6 +1458,11 @@ static void xs_sock_mark_closed(struct rpc_xprt *xprt)
 	clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
 	clear_bit(XPRT_CLOSING, &xprt->state);
 	smp_mb__after_clear_bit();
+}
+
+static void xs_sock_mark_closed(struct rpc_xprt *xprt)
+{
+	xs_sock_reset_connection_flags(xprt);
 	/* Mark transport as closed and wake up all pending tasks */
 	xprt_disconnect_done(xprt);
 }
@@ -1516,6 +1518,7 @@ static void xs_tcp_state_change(struct sock *sk)
 	case TCP_CLOSE_WAIT:
 		/* The server initiated a shutdown of the socket */
 		xprt->connect_cookie++;
+		clear_bit(XPRT_CONNECTED, &xprt->state);
 		xs_tcp_force_close(xprt);
 	case TCP_CLOSING:
 		/*
@@ -1540,25 +1543,6 @@ static void xs_tcp_state_change(struct sock *sk)
 	read_unlock_bh(&sk->sk_callback_lock);
 }
 
-/**
- * xs_error_report - callback mainly for catching socket errors
- * @sk: socket
- */
-static void xs_error_report(struct sock *sk)
-{
-	struct rpc_xprt *xprt;
-
-	read_lock_bh(&sk->sk_callback_lock);
-	if (!(xprt = xprt_from_sock(sk)))
-		goto out;
-	dprintk("RPC:       %s client %p...\n"
-			"RPC:       error %d\n",
-			__func__, xprt, sk->sk_err);
-	xprt_wake_pending_tasks(xprt, -EAGAIN);
-out:
-	read_unlock_bh(&sk->sk_callback_lock);
-}
-
 static void xs_write_space(struct sock *sk)
 {
 	struct socket *sock;
@@ -1858,7 +1842,6 @@ static int xs_local_finish_connecting(struct rpc_xprt *xprt,
 		sk->sk_user_data = xprt;
 		sk->sk_data_ready = xs_local_data_ready;
 		sk->sk_write_space = xs_udp_write_space;
-		sk->sk_error_report = xs_error_report;
 		sk->sk_allocation = GFP_ATOMIC;
 
 		xprt_clear_connected(xprt);
@@ -1983,7 +1966,6 @@ static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
 		sk->sk_user_data = xprt;
 		sk->sk_data_ready = xs_udp_data_ready;
 		sk->sk_write_space = xs_udp_write_space;
-		sk->sk_error_report = xs_error_report;
 		sk->sk_no_check = UDP_CSUM_NORCV;
 		sk->sk_allocation = GFP_ATOMIC;
 
@@ -2050,10 +2032,8 @@ static void xs_abort_connection(struct sock_xprt *transport)
 	any.sa_family = AF_UNSPEC;
 	result = kernel_connect(transport->sock, &any, sizeof(any), 0);
 	if (!result)
-		xs_sock_mark_closed(&transport->xprt);
+		xs_sock_reset_connection_flags(&transport->xprt);
-	else
+	dprintk("RPC:       AF_UNSPEC connect return code %d\n", result);
-		dprintk("RPC:       AF_UNSPEC connect return code %d\n",
-				result);
 }
 
 static void xs_tcp_reuse_connection(struct sock_xprt *transport)
@@ -2098,7 +2078,6 @@ static int xs_tcp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
 		sk->sk_data_ready = xs_tcp_data_ready;
 		sk->sk_state_change = xs_tcp_state_change;
 		sk->sk_write_space = xs_tcp_write_space;
-		sk->sk_error_report = xs_error_report;
 		sk->sk_allocation = GFP_ATOMIC;
 
 		/* socket options */