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

2 files changed, 42 insertions, 56 deletions

diff --git a/fs/lockd/mon.c b/fs/lockd/mon.c
index e4fb3ba5a58a..3d7e09bcc0e9 100644
--- a/fs/lockd/mon.c
+++ b/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;
+        struct rpc_clnt *clnt, *new;
         struct lockd_net *ln = net_generic(net, lockd_net_id);
 
-        spin_lock(&ln->nsm_clnt_lock);
-        if (ln->nsm_users) {
-                ln->nsm_users++;
-                clnt = ln->nsm_clnt;
-                spin_unlock(&ln->nsm_clnt_lock);
+        clnt = nsm_client_set(ln, NULL);
+        if (clnt != NULL)
                 goto out;
-        }
-        spin_unlock(&ln->nsm_clnt_lock);
 
-        mutex_lock(&nsm_create_mutex);
-        clnt = nsm_create(net);
-        if (!IS_ERR(clnt)) {
-                ln->nsm_clnt = clnt;
-                smp_wmb();
-                ln->nsm_users = 1;
-        }
-        mutex_unlock(&nsm_create_mutex);
+        clnt = new = nsm_create(net);
+        if (IS_ERR(clnt))
+                goto out;
+
+        clnt = nsm_client_set(ln, new);
+        if (clnt != new)
+                rpc_shutdown_client(new);
 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;
-        int shutdown = 0;
+        struct rpc_clnt *clnt = NULL;
 
         spin_lock(&ln->nsm_clnt_lock);
-        if (ln->nsm_users) {
-                if (--ln->nsm_users)
-                        ln->nsm_clnt = NULL;
-                shutdown = !ln->nsm_users;
+        ln->nsm_users--;
+        if (ln->nsm_users == 0) {
+                clnt = ln->nsm_clnt;
+                ln->nsm_clnt = NULL;
         }
         spin_unlock(&ln->nsm_clnt_lock);
-
-        if (shutdown)
+        if (clnt != NULL)
                 rpc_shutdown_client(clnt);
 }
 
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index aaaadfbe36e9..75853cabf4c9 100644
--- a/net/sunrpc/xprtsock.c
+++ b/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);
-        else
-                dprintk("RPC:       AF_UNSPEC connect return code %d\n",
-                                result);
+                xs_sock_reset_connection_flags(&transport->xprt);
+        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 */