1 files changed, 67 insertions, 56 deletions

diff --git a/fs/ocfs2/cluster/tcp.c b/fs/ocfs2/cluster/tcp.c
index 2cd2406b414..681691bc233 100644
--- a/fs/ocfs2/cluster/tcp.c
+++ b/fs/ocfs2/cluster/tcp.c
@@ -108,7 +108,7 @@ static struct rb_root o2net_handler_tree = RB_ROOT;
 static struct o2net_node o2net_nodes[O2NM_MAX_NODES];
 
 /* XXX someday we'll need better accounting */
-static struct socket *o2net_listen_sock = NULL;
+static struct socket *o2net_listen_sock;
 
 /*
  * listen work is only queued by the listening socket callbacks on the
@@ -137,7 +137,7 @@ static int o2net_sys_err_translations[O2NET_ERR_MAX] =
 static void o2net_sc_connect_completed(struct work_struct *work);
 static void o2net_rx_until_empty(struct work_struct *work);
 static void o2net_shutdown_sc(struct work_struct *work);
-static void o2net_listen_data_ready(struct sock *sk, int bytes);
+static void o2net_listen_data_ready(struct sock *sk);
 static void o2net_sc_send_keep_req(struct work_struct *work);
 static void o2net_idle_timer(unsigned long data);
 static void o2net_sc_postpone_idle(struct o2net_sock_container *sc);
@@ -262,17 +262,17 @@ static void o2net_update_recv_stats(struct o2net_sock_container *sc)
 
 #endif /* CONFIG_OCFS2_FS_STATS */
 
-static inline int o2net_reconnect_delay(void)
+static inline unsigned int o2net_reconnect_delay(void)
 {
 	return o2nm_single_cluster->cl_reconnect_delay_ms;
 }
 
-static inline int o2net_keepalive_delay(void)
+static inline unsigned int o2net_keepalive_delay(void)
 {
 	return o2nm_single_cluster->cl_keepalive_delay_ms;
 }
 
-static inline int o2net_idle_timeout(void)
+static inline unsigned int o2net_idle_timeout(void)
 {
 	return o2nm_single_cluster->cl_idle_timeout_ms;
 }
@@ -597,9 +597,9 @@ static void o2net_set_nn_state(struct o2net_node *nn,
 }
 
 /* see o2net_register_callbacks() */
-static void o2net_data_ready(struct sock *sk, int bytes)
+static void o2net_data_ready(struct sock *sk)
 {
-	void (*ready)(struct sock *sk, int bytes);
+	void (*ready)(struct sock *sk);
 
 	read_lock(&sk->sk_callback_lock);
 	if (sk->sk_user_data) {
@@ -613,7 +613,7 @@ static void o2net_data_ready(struct sock *sk, int bytes)
 	}
 	read_unlock(&sk->sk_callback_lock);
 
-	ready(sk, bytes);
+	ready(sk);
 }
 
 /* see o2net_register_callbacks() */
@@ -916,57 +916,30 @@ static struct o2net_msg_handler *o2net_handler_get(u32 msg_type, u32 key)
 
 static int o2net_recv_tcp_msg(struct socket *sock, void *data, size_t len)
 {
-	int ret;
-	mm_segment_t oldfs;
-	struct kvec vec = {
-		.iov_len = len,
-		.iov_base = data,
-	};
-	struct msghdr msg = {
-		.msg_iovlen = 1,
-		.msg_iov = (struct iovec *)&vec,
-       		.msg_flags = MSG_DONTWAIT,
-	};
-
-	oldfs = get_fs();
-	set_fs(get_ds());
-	ret = sock_recvmsg(sock, &msg, len, msg.msg_flags);
-	set_fs(oldfs);
-
-	return ret;
+	struct kvec vec = { .iov_len = len, .iov_base = data, };
+	struct msghdr msg = { .msg_flags = MSG_DONTWAIT, };
+	return kernel_recvmsg(sock, &msg, &vec, 1, len, msg.msg_flags);
 }
 
 static int o2net_send_tcp_msg(struct socket *sock, struct kvec *vec,
 			      size_t veclen, size_t total)
 {
 	int ret;
-	mm_segment_t oldfs;
-	struct msghdr msg = {
-		.msg_iov = (struct iovec *)vec,
-		.msg_iovlen = veclen,
-	};
+	struct msghdr msg;
 
 	if (sock == NULL) {
 		ret = -EINVAL;
 		goto out;
 	}
 
-	oldfs = get_fs();
-	set_fs(get_ds());
-	ret = sock_sendmsg(sock, &msg, total);
-	set_fs(oldfs);
-	if (ret != total) {
-		mlog(ML_ERROR, "sendmsg returned %d instead of %zu\n", ret,
-		     total);
-		if (ret >= 0)
-			ret = -EPIPE; /* should be smarter, I bet */
-		goto out;
-	}
-
-	ret = 0;
+	ret = kernel_sendmsg(sock, &msg, vec, veclen, total);
+	if (likely(ret == total))
+		return 0;
+	mlog(ML_ERROR, "sendmsg returned %d instead of %zu\n", ret, total);
+	if (ret >= 0)
+		ret = -EPIPE; /* should be smarter, I bet */
 out:
-	if (ret < 0)
-		mlog(0, "returning error: %d\n", ret);
+	mlog(0, "returning error: %d\n", ret);
 	return ret;
 }
 
@@ -1826,7 +1799,7 @@ int o2net_register_hb_callbacks(void)
 
 /* ------------------------------------------------------------ */
 
-static int o2net_accept_one(struct socket *sock)
+static int o2net_accept_one(struct socket *sock, int *more)
 {
 	int ret, slen;
 	struct sockaddr_in sin;
@@ -1837,6 +1810,7 @@ static int o2net_accept_one(struct socket *sock)
 	struct o2net_node *nn;
 
 	BUG_ON(sock == NULL);
+	*more = 0;
 	ret = sock_create_lite(sock->sk->sk_family, sock->sk->sk_type,
 			       sock->sk->sk_protocol, &new_sock);
 	if (ret)
@@ -1848,6 +1822,7 @@ static int o2net_accept_one(struct socket *sock)
 	if (ret < 0)
 		goto out;
 
+	*more = 1;
 	new_sock->sk->sk_allocation = GFP_ATOMIC;
 
 	ret = o2net_set_nodelay(new_sock);
@@ -1946,16 +1921,41 @@ out:
 	return ret;
 }
 
+/*
+ * This function is invoked in response to one or more
+ * pending accepts at softIRQ level. We must drain the
+ * entire que before returning.
+ */
+
 static void o2net_accept_many(struct work_struct *work)
 {
 	struct socket *sock = o2net_listen_sock;
-	while (o2net_accept_one(sock) == 0)
+	int	more;
+	int	err;
+
+	/*
+	 * It is critical to note that due to interrupt moderation
+	 * at the network driver level, we can't assume to get a
+	 * softIRQ for every single conn since tcp SYN packets
+	 * can arrive back-to-back, and therefore many pending
+	 * accepts may result in just 1 softIRQ. If we terminate
+	 * the o2net_accept_one() loop upon seeing an err, what happens
+	 * to the rest of the conns in the queue? If no new SYN
+	 * arrives for hours, no softIRQ  will be delivered,
+	 * and the connections will just sit in the queue.
+	 */
+
+	for (;;) {
+		err = o2net_accept_one(sock, &more);
+		if (!more)
+			break;
 		cond_resched();
+	}
 }
 
-static void o2net_listen_data_ready(struct sock *sk, int bytes)
+static void o2net_listen_data_ready(struct sock *sk)
 {
-	void (*ready)(struct sock *sk, int bytes);
+	void (*ready)(struct sock *sk);
 
 	read_lock(&sk->sk_callback_lock);
 	ready = sk->sk_user_data;
@@ -1964,18 +1964,29 @@ static void o2net_listen_data_ready(struct sock *sk, int bytes)
 		goto out;
 	}
 
-	/* ->sk_data_ready is also called for a newly established child socket
-	 * before it has been accepted and the acceptor has set up their
-	 * data_ready.. we only want to queue listen work for our listening
-	 * socket */
+	/* This callback may called twice when a new connection
+	 * is  being established as a child socket inherits everything
+	 * from a parent LISTEN socket, including the data_ready cb of
+	 * the parent. This leads to a hazard. In o2net_accept_one()
+	 * we are still initializing the child socket but have not
+	 * changed the inherited data_ready callback yet when
+	 * data starts arriving.
+	 * We avoid this hazard by checking the state.
+	 * For the listening socket,  the state will be TCP_LISTEN; for the new
+	 * socket, will be  TCP_ESTABLISHED. Also, in this case,
+	 * sk->sk_user_data is not a valid function pointer.
+	 */
+
 	if (sk->sk_state == TCP_LISTEN) {
-		mlog(ML_TCP, "bytes: %d\n", bytes);
 		queue_work(o2net_wq, &o2net_listen_work);
+	} else {
+		ready = NULL;
 	}
 
 out:
 	read_unlock(&sk->sk_callback_lock);
-	ready(sk, bytes);
+	if (ready != NULL)
+		ready(sk);
 }
 
 static int o2net_open_listening_sock(__be32 addr, __be16 port)