Merge tag 'dlm-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/linux-dlm

Pull dlm updates from David Teigland:
 "This set mainly includes a change to the way the dlm uses the SCTP API
  in the kernel, removing the direct dependency on the sctp module.
  Other odd SCTP-related fixes are also included.

  The other notable fix is for a long standing regression in the
  behavior of lock value blocks for user space locks"

* tag 'dlm-4.3' of git://git.kernel.org/pub/scm/linux/kernel/git/teigland/linux-dlm:
  dlm: print error from kernel_sendpage
  dlm: fix lvb copy for user locks
  dlm: sctp_accept_from_sock() can be static
  dlm: fix reconnecting but not sending data
  dlm: replace BUG_ON with a less severe handling
  dlm: use sctp 1-to-1 API
  dlm: fix not reconnecting on connecting error handling
  dlm: fix race while closing connections
  dlm: fix connection stealing if using SCTP

2 files changed, 304 insertions, 446 deletions

diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index 754fd6c0b747..87e9d796cf7d 100644
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -120,12 +120,11 @@ struct connection {
 	struct cbuf cb;
 	int retries;
 #define MAX_CONNECT_RETRIES 3
-	int sctp_assoc;
 	struct hlist_node list;
 	struct connection *othercon;
 	struct work_struct rwork; /* Receive workqueue */
 	struct work_struct swork; /* Send workqueue */
-	bool try_new_addr;
+	void (*orig_error_report)(struct sock *sk);
 };
 #define sock2con(x) ((struct connection *)(x)->sk_user_data)
 
@@ -252,26 +251,6 @@ static struct connection *nodeid2con(int nodeid, gfp_t allocation)
 	return con;
 }
 
-/* This is a bit drastic, but only called when things go wrong */
-static struct connection *assoc2con(int assoc_id)
-{
-	int i;
-	struct connection *con;
-
-	mutex_lock(&connections_lock);
-
-	for (i = 0 ; i < CONN_HASH_SIZE; i++) {
-		hlist_for_each_entry(con, &connection_hash[i], list) {
-			if (con->sctp_assoc == assoc_id) {
-				mutex_unlock(&connections_lock);
-				return con;
-			}
-		}
-	}
-	mutex_unlock(&connections_lock);
-	return NULL;
-}
-
 static struct dlm_node_addr *find_node_addr(int nodeid)
 {
 	struct dlm_node_addr *na;
@@ -322,14 +301,14 @@ static int nodeid_to_addr(int nodeid, struct sockaddr_storage *sas_out,
 	spin_lock(&dlm_node_addrs_spin);
 	na = find_node_addr(nodeid);
 	if (na && na->addr_count) {
+		memcpy(&sas, na->addr[na->curr_addr_index],
+		       sizeof(struct sockaddr_storage));
+
 		if (try_new_addr) {
 			na->curr_addr_index++;
 			if (na->curr_addr_index == na->addr_count)
 				na->curr_addr_index = 0;
 		}
-
-		memcpy(&sas, na->addr[na->curr_addr_index ],
-			sizeof(struct sockaddr_storage));
 	}
 	spin_unlock(&dlm_node_addrs_spin);
 
@@ -459,18 +438,23 @@ static inline void lowcomms_connect_sock(struct connection *con)
 
 static void lowcomms_state_change(struct sock *sk)
 {
-	if (sk->sk_state == TCP_ESTABLISHED)
+	/* SCTP layer is not calling sk_data_ready when the connection
+	 * is done, so we catch the signal through here. Also, it
+	 * doesn't switch socket state when entering shutdown, so we
+	 * skip the write in that case.
+	 */
+	if (sk->sk_shutdown) {
+		if (sk->sk_shutdown == RCV_SHUTDOWN)
+			lowcomms_data_ready(sk);
+	} else if (sk->sk_state == TCP_ESTABLISHED) {
 		lowcomms_write_space(sk);
+	}
 }
 
 int dlm_lowcomms_connect_node(int nodeid)
 {
 	struct connection *con;
 
-	/* with sctp there's no connecting without sending */
-	if (dlm_config.ci_protocol != 0)
-		return 0;
-
 	if (nodeid == dlm_our_nodeid())
 		return 0;
 
@@ -481,6 +465,43 @@ int dlm_lowcomms_connect_node(int nodeid)
 	return 0;
 }
 
+static void lowcomms_error_report(struct sock *sk)
+{
+	struct connection *con = sock2con(sk);
+	struct sockaddr_storage saddr;
+
+	if (nodeid_to_addr(con->nodeid, &saddr, NULL, false)) {
+		printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
+				   "sending to node %d, port %d, "
+				   "sk_err=%d/%d\n", dlm_our_nodeid(),
+				   con->nodeid, dlm_config.ci_tcp_port,
+				   sk->sk_err, sk->sk_err_soft);
+		return;
+	} else if (saddr.ss_family == AF_INET) {
+		struct sockaddr_in *sin4 = (struct sockaddr_in *)&saddr;
+
+		printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
+				   "sending to node %d at %pI4, port %d, "
+				   "sk_err=%d/%d\n", dlm_our_nodeid(),
+				   con->nodeid, &sin4->sin_addr.s_addr,
+				   dlm_config.ci_tcp_port, sk->sk_err,
+				   sk->sk_err_soft);
+	} else {
+		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&saddr;
+
+		printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
+				   "sending to node %d at %u.%u.%u.%u, "
+				   "port %d, sk_err=%d/%d\n", dlm_our_nodeid(),
+				   con->nodeid, sin6->sin6_addr.s6_addr32[0],
+				   sin6->sin6_addr.s6_addr32[1],
+				   sin6->sin6_addr.s6_addr32[2],
+				   sin6->sin6_addr.s6_addr32[3],
+				   dlm_config.ci_tcp_port, sk->sk_err,
+				   sk->sk_err_soft);
+	}
+	con->orig_error_report(sk);
+}
+
 /* Make a socket active */
 static void add_sock(struct socket *sock, struct connection *con)
 {
@@ -492,6 +513,8 @@ static void add_sock(struct socket *sock, struct connection *con)
 	con->sock->sk->sk_state_change = lowcomms_state_change;
 	con->sock->sk->sk_user_data = con;
 	con->sock->sk->sk_allocation = GFP_NOFS;
+	con->orig_error_report = con->sock->sk->sk_error_report;
+	con->sock->sk->sk_error_report = lowcomms_error_report;
 }
 
 /* Add the port number to an IPv6 or 4 sockaddr and return the address
@@ -514,17 +537,24 @@ static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port,
 }
 
 /* Close a remote connection and tidy up */
-static void close_connection(struct connection *con, bool and_other)
+static void close_connection(struct connection *con, bool and_other,
+			     bool tx, bool rx)
 {
-	mutex_lock(&con->sock_mutex);
+	clear_bit(CF_CONNECT_PENDING, &con->flags);
+	clear_bit(CF_WRITE_PENDING, &con->flags);
+	if (tx && cancel_work_sync(&con->swork))
+		log_print("canceled swork for node %d", con->nodeid);
+	if (rx && cancel_work_sync(&con->rwork))
+		log_print("canceled rwork for node %d", con->nodeid);
 
+	mutex_lock(&con->sock_mutex);
 	if (con->sock) {
 		sock_release(con->sock);
 		con->sock = NULL;
 	}
 	if (con->othercon && and_other) {
 		/* Will only re-enter once. */
-		close_connection(con->othercon, false);
+		close_connection(con->othercon, false, true, true);
 	}
 	if (con->rx_page) {
 		__free_page(con->rx_page);
@@ -535,254 +565,6 @@ static void close_connection(struct connection *con, bool and_other)
 	mutex_unlock(&con->sock_mutex);
 }
 
-/* We only send shutdown messages to nodes that are not part of the cluster */
-static void sctp_send_shutdown(sctp_assoc_t associd)
-{
-	static char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
-	struct msghdr outmessage;
-	struct cmsghdr *cmsg;
-	struct sctp_sndrcvinfo *sinfo;
-	int ret;
-	struct connection *con;
-
-	con = nodeid2con(0,0);
-	BUG_ON(con == NULL);
-
-	outmessage.msg_name = NULL;
-	outmessage.msg_namelen = 0;
-	outmessage.msg_control = outcmsg;
-	outmessage.msg_controllen = sizeof(outcmsg);
-	outmessage.msg_flags = MSG_EOR;
-
-	cmsg = CMSG_FIRSTHDR(&outmessage);
-	cmsg->cmsg_level = IPPROTO_SCTP;
-	cmsg->cmsg_type = SCTP_SNDRCV;
-	cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
-	outmessage.msg_controllen = cmsg->cmsg_len;
-	sinfo = CMSG_DATA(cmsg);
-	memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo));
-
-	sinfo->sinfo_flags |= MSG_EOF;
-	sinfo->sinfo_assoc_id = associd;
-
-	ret = kernel_sendmsg(con->sock, &outmessage, NULL, 0, 0);
-
-	if (ret != 0)
-		log_print("send EOF to node failed: %d", ret);
-}
-
-static void sctp_init_failed_foreach(struct connection *con)
-{
-
-	/*
-	 * Don't try to recover base con and handle race where the
-	 * other node's assoc init creates a assoc and we get that
-	 * notification, then we get a notification that our attempt
-	 * failed due. This happens when we are still trying the primary
-	 * address, but the other node has already tried secondary addrs
-	 * and found one that worked.
-	 */
-	if (!con->nodeid || con->sctp_assoc)
-		return;
-
-	log_print("Retrying SCTP association init for node %d\n", con->nodeid);
-
-	con->try_new_addr = true;
-	con->sctp_assoc = 0;
-	if (test_and_clear_bit(CF_INIT_PENDING, &con->flags)) {
-		if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags))
-			queue_work(send_workqueue, &con->swork);
-	}
-}
-
-/* INIT failed but we don't know which node...
-   restart INIT on all pending nodes */
-static void sctp_init_failed(void)
-{
-	mutex_lock(&connections_lock);
-
-	foreach_conn(sctp_init_failed_foreach);
-
-	mutex_unlock(&connections_lock);
-}
-
-static void retry_failed_sctp_send(struct connection *recv_con,
-				   struct sctp_send_failed *sn_send_failed,
-				   char *buf)
-{
-	int len = sn_send_failed->ssf_length - sizeof(struct sctp_send_failed);
-	struct dlm_mhandle *mh;
-	struct connection *con;
-	char *retry_buf;
-	int nodeid = sn_send_failed->ssf_info.sinfo_ppid;
-
-	log_print("Retry sending %d bytes to node id %d", len, nodeid);
-	
-	if (!nodeid) {
-		log_print("Shouldn't resend data via listening connection.");
-		return;
-	}
-
-	con = nodeid2con(nodeid, 0);
-	if (!con) {
-		log_print("Could not look up con for nodeid %d\n",
-			  nodeid);
-		return;
-	}
-
-	mh = dlm_lowcomms_get_buffer(nodeid, len, GFP_NOFS, &retry_buf);
-	if (!mh) {
-		log_print("Could not allocate buf for retry.");
-		return;
-	}
-	memcpy(retry_buf, buf + sizeof(struct sctp_send_failed), len);
-	dlm_lowcomms_commit_buffer(mh);
-
-	/*
-	 * If we got a assoc changed event before the send failed event then
-	 * we only need to retry the send.
-	 */
-	if (con->sctp_assoc) {
-		if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags))
-			queue_work(send_workqueue, &con->swork);
-	} else
-		sctp_init_failed_foreach(con);
-}
-
-/* Something happened to an association */
-static void process_sctp_notification(struct connection *con,
-				      struct msghdr *msg, char *buf)
-{
-	union sctp_notification *sn = (union sctp_notification *)buf;
-	struct linger linger;
-
-	switch (sn->sn_header.sn_type) {
-	case SCTP_SEND_FAILED:
-		retry_failed_sctp_send(con, &sn->sn_send_failed, buf);
-		break;
-	case SCTP_ASSOC_CHANGE:
-		switch (sn->sn_assoc_change.sac_state) {
-		case SCTP_COMM_UP:
-		case SCTP_RESTART:
-		{
-			/* Check that the new node is in the lockspace */
-			struct sctp_prim prim;
-			int nodeid;
-			int prim_len, ret;
-			int addr_len;
-			struct connection *new_con;
-
-			/*
-			 * We get this before any data for an association.
-			 * We verify that the node is in the cluster and
-			 * then peel off a socket for it.
-			 */
-			if ((int)sn->sn_assoc_change.sac_assoc_id <= 0) {
-				log_print("COMM_UP for invalid assoc ID %d",
-					 (int)sn->sn_assoc_change.sac_assoc_id);
-				sctp_init_failed();
-				return;
-			}
-			memset(&prim, 0, sizeof(struct sctp_prim));
-			prim_len = sizeof(struct sctp_prim);
-			prim.ssp_assoc_id = sn->sn_assoc_change.sac_assoc_id;
-
-			ret = kernel_getsockopt(con->sock,
-						IPPROTO_SCTP,
-						SCTP_PRIMARY_ADDR,
-						(char*)&prim,
-						&prim_len);
-			if (ret < 0) {
-				log_print("getsockopt/sctp_primary_addr on "
-					  "new assoc %d failed : %d",
-					  (int)sn->sn_assoc_change.sac_assoc_id,
-					  ret);
-
-				/* Retry INIT later */
-				new_con = assoc2con(sn->sn_assoc_change.sac_assoc_id);
-				if (new_con)
-					clear_bit(CF_CONNECT_PENDING, &con->flags);
-				return;
-			}
-			make_sockaddr(&prim.ssp_addr, 0, &addr_len);
-			if (addr_to_nodeid(&prim.ssp_addr, &nodeid)) {
-				unsigned char *b=(unsigned char *)&prim.ssp_addr;
-				log_print("reject connect from unknown addr");
-				print_hex_dump_bytes("ss: ", DUMP_PREFIX_NONE, 
-						     b, sizeof(struct sockaddr_storage));
-				sctp_send_shutdown(prim.ssp_assoc_id);
-				return;
-			}
-
-			new_con = nodeid2con(nodeid, GFP_NOFS);
-			if (!new_con)
-				return;
-
-			/* Peel off a new sock */
-			lock_sock(con->sock->sk);
-			ret = sctp_do_peeloff(con->sock->sk,
-				sn->sn_assoc_change.sac_assoc_id,
-				&new_con->sock);
-			release_sock(con->sock->sk);
-			if (ret < 0) {
-				log_print("Can't peel off a socket for "
-					  "connection %d to node %d: err=%d",
-					  (int)sn->sn_assoc_change.sac_assoc_id,
-					  nodeid, ret);
-				return;
-			}
-			add_sock(new_con->sock, new_con);
-
-			linger.l_onoff = 1;
-			linger.l_linger = 0;
-			ret = kernel_setsockopt(new_con->sock, SOL_SOCKET, SO_LINGER,
-						(char *)&linger, sizeof(linger));
-			if (ret < 0)
-				log_print("set socket option SO_LINGER failed");
-
-			log_print("connecting to %d sctp association %d",
-				 nodeid, (int)sn->sn_assoc_change.sac_assoc_id);
-
-			new_con->sctp_assoc = sn->sn_assoc_change.sac_assoc_id;
-			new_con->try_new_addr = false;
-			/* Send any pending writes */
-			clear_bit(CF_CONNECT_PENDING, &new_con->flags);
-			clear_bit(CF_INIT_PENDING, &new_con->flags);
-			if (!test_and_set_bit(CF_WRITE_PENDING, &new_con->flags)) {
-				queue_work(send_workqueue, &new_con->swork);
-			}
-			if (!test_and_set_bit(CF_READ_PENDING, &new_con->flags))
-				queue_work(recv_workqueue, &new_con->rwork);
-		}
-		break;
-
-		case SCTP_COMM_LOST:
-		case SCTP_SHUTDOWN_COMP:
-		{
-			con = assoc2con(sn->sn_assoc_change.sac_assoc_id);
-			if (con) {
-				con->sctp_assoc = 0;
-			}
-		}
-		break;
-
-		case SCTP_CANT_STR_ASSOC:
-		{
-			/* Will retry init when we get the send failed notification */
-			log_print("Can't start SCTP association - retrying");
-		}
-		break;
-
-		default:
-			log_print("unexpected SCTP assoc change id=%d state=%d",
-				  (int)sn->sn_assoc_change.sac_assoc_id,
-				  sn->sn_assoc_change.sac_state);
-		}
-	default:
-		; /* fall through */
-	}
-}
-
 /* Data received from remote end */
 static int receive_from_sock(struct connection *con)
 {
@@ -793,7 +575,6 @@ static int receive_from_sock(struct connection *con)
 	int r;
 	int call_again_soon = 0;
 	int nvec;
-	char incmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
 
 	mutex_lock(&con->sock_mutex);
 
@@ -801,6 +582,10 @@ static int receive_from_sock(struct connection *con)
 		ret = -EAGAIN;
 		goto out_close;
 	}
+	if (con->nodeid == 0) {
+		ret = -EINVAL;
+		goto out_close;
+	}
 
 	if (con->rx_page == NULL) {
 		/*
@@ -813,11 +598,6 @@ static int receive_from_sock(struct connection *con)
 		cbuf_init(&con->cb, PAGE_CACHE_SIZE);
 	}
 
-	/* Only SCTP needs these really */
-	memset(&incmsg, 0, sizeof(incmsg));
-	msg.msg_control = incmsg;
-	msg.msg_controllen = sizeof(incmsg);
-
 	/*
 	 * iov[0] is the bit of the circular buffer between the current end
 	 * point (cb.base + cb.len) and the end of the buffer.
@@ -843,31 +623,18 @@ static int receive_from_sock(struct connection *con)
 			       MSG_DONTWAIT | MSG_NOSIGNAL);
 	if (ret <= 0)
 		goto out_close;
-
-	/* Process SCTP notifications */
-	if (msg.msg_flags & MSG_NOTIFICATION) {
-		msg.msg_control = incmsg;
-		msg.msg_controllen = sizeof(incmsg);
-
-		process_sctp_notification(con, &msg,
-				page_address(con->rx_page) + con->cb.base);
-		mutex_unlock(&con->sock_mutex);
-		return 0;
-	}
-	BUG_ON(con->nodeid == 0);
-
-	if (ret == len)
+	else if (ret == len)
 		call_again_soon = 1;
+
 	cbuf_add(&con->cb, ret);
 	ret = dlm_process_incoming_buffer(con->nodeid,
 					  page_address(con->rx_page),
 					  con->cb.base, con->cb.len,
 					  PAGE_CACHE_SIZE);
 	if (ret == -EBADMSG) {
-		log_print("lowcomms: addr=%p, base=%u, len=%u, "
-			  "iov_len=%u, iov_base[0]=%p, read=%d",
-			  page_address(con->rx_page), con->cb.base, con->cb.len,
-			  len, iov[0].iov_base, r);
+		log_print("lowcomms: addr=%p, base=%u, len=%u, read=%d",
+			  page_address(con->rx_page), con->cb.base,
+			  con->cb.len, r);
 	}
 	if (ret < 0)
 		goto out_close;
@@ -892,7 +659,7 @@ out_resched:
 out_close:
 	mutex_unlock(&con->sock_mutex);
 	if (ret != -EAGAIN) {
-		close_connection(con, false);
+		close_connection(con, false, true, false);
 		/* Reconnect when there is something to send */
 	}
 	/* Don't return success if we really got EOF */
@@ -1033,6 +800,120 @@ accept_err:
 	return result;
 }
 
+static int sctp_accept_from_sock(struct connection *con)
+{
+	/* Check that the new node is in the lockspace */
+	struct sctp_prim prim;
+	int nodeid;
+	int prim_len, ret;
+	int addr_len;
+	struct connection *newcon;
+	struct connection *addcon;
+	struct socket *newsock;
+
+	mutex_lock(&connections_lock);
+	if (!dlm_allow_conn) {
+		mutex_unlock(&connections_lock);
+		return -1;
+	}
+	mutex_unlock(&connections_lock);
+
+	mutex_lock_nested(&con->sock_mutex, 0);
+
+	ret = kernel_accept(con->sock, &newsock, O_NONBLOCK);
+	if (ret < 0)
+		goto accept_err;
+
+	memset(&prim, 0, sizeof(struct sctp_prim));
+	prim_len = sizeof(struct sctp_prim);
+
+	ret = kernel_getsockopt(newsock, IPPROTO_SCTP, SCTP_PRIMARY_ADDR,
+				(char *)&prim, &prim_len);
+	if (ret < 0) {
+		log_print("getsockopt/sctp_primary_addr failed: %d", ret);
+		goto accept_err;
+	}
+
+	make_sockaddr(&prim.ssp_addr, 0, &addr_len);
+	if (addr_to_nodeid(&prim.ssp_addr, &nodeid)) {
+		unsigned char *b = (unsigned char *)&prim.ssp_addr;
+
+		log_print("reject connect from unknown addr");
+		print_hex_dump_bytes("ss: ", DUMP_PREFIX_NONE,
+				     b, sizeof(struct sockaddr_storage));
+		goto accept_err;
+	}
+
+	newcon = nodeid2con(nodeid, GFP_NOFS);
+	if (!newcon) {
+		ret = -ENOMEM;
+		goto accept_err;
+	}
+
+	mutex_lock_nested(&newcon->sock_mutex, 1);
+
+	if (newcon->sock) {
+		struct connection *othercon = newcon->othercon;
+
+		if (!othercon) {
+			othercon = kmem_cache_zalloc(con_cache, GFP_NOFS);
+			if (!othercon) {
+				log_print("failed to allocate incoming socket");
+				mutex_unlock(&newcon->sock_mutex);
+				ret = -ENOMEM;
+				goto accept_err;
+			}
+			othercon->nodeid = nodeid;
+			othercon->rx_action = receive_from_sock;
+			mutex_init(&othercon->sock_mutex);
+			INIT_WORK(&othercon->swork, process_send_sockets);
+			INIT_WORK(&othercon->rwork, process_recv_sockets);
+			set_bit(CF_IS_OTHERCON, &othercon->flags);
+		}
+		if (!othercon->sock) {
+			newcon->othercon = othercon;
+			othercon->sock = newsock;
+			newsock->sk->sk_user_data = othercon;
+			add_sock(newsock, othercon);
+			addcon = othercon;
+		} else {
+			printk("Extra connection from node %d attempted\n", nodeid);
+			ret = -EAGAIN;
+			mutex_unlock(&newcon->sock_mutex);
+			goto accept_err;
+		}
+	} else {
+		newsock->sk->sk_user_data = newcon;
+		newcon->rx_action = receive_from_sock;
+		add_sock(newsock, newcon);
+		addcon = newcon;
+	}
+
+	log_print("connected to %d", nodeid);
+
+	mutex_unlock(&newcon->sock_mutex);
+
+	/*
+	 * Add it to the active queue in case we got data
+	 * between processing the accept adding the socket
+	 * to the read_sockets list
+	 */
+	if (!test_and_set_bit(CF_READ_PENDING, &addcon->flags))
+		queue_work(recv_workqueue, &addcon->rwork);
+	mutex_unlock(&con->sock_mutex);
+
+	return 0;
+
+accept_err:
+	mutex_unlock(&con->sock_mutex);
+	if (newsock)
+		sock_release(newsock);
+	if (ret != -EAGAIN)
+		log_print("error accepting connection from node: %d", ret);
+
+	return ret;
+}
+
 static void free_entry(struct writequeue_entry *e)
 {
 	__free_page(e->page);
@@ -1057,97 +938,129 @@ static void writequeue_entry_complete(struct writequeue_entry *e, int completed)
 	}
 }
 
+/*
+ * sctp_bind_addrs - bind a SCTP socket to all our addresses
+ */
+static int sctp_bind_addrs(struct connection *con, uint16_t port)
+{
+	struct sockaddr_storage localaddr;
+	int i, addr_len, result = 0;
+
+	for (i = 0; i < dlm_local_count; i++) {
+		memcpy(&localaddr, dlm_local_addr[i], sizeof(localaddr));
+		make_sockaddr(&localaddr, port, &addr_len);
+
+		if (!i)
+			result = kernel_bind(con->sock,
+					     (struct sockaddr *)&localaddr,
+					     addr_len);
+		else
+			result = kernel_setsockopt(con->sock, SOL_SCTP,
+						   SCTP_SOCKOPT_BINDX_ADD,
+						   (char *)&localaddr, addr_len);
+
+		if (result < 0) {
+			log_print("Can't bind to %d addr number %d, %d.\n",
+				  port, i + 1, result);
+			break;
+		}
+	}
+	return result;
+}
+
 /* Initiate an SCTP association.
    This is a special case of send_to_sock() in that we don't yet have a
    peeled-off socket for this association, so we use the listening socket
    and add the primary IP address of the remote node.
  */
-static void sctp_init_assoc(struct connection *con)
+static void sctp_connect_to_sock(struct connection *con)
 {
-	struct sockaddr_storage rem_addr;
-	char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
-	struct msghdr outmessage;
-	struct cmsghdr *cmsg;
-	struct sctp_sndrcvinfo *sinfo;
-	struct connection *base_con;
-	struct writequeue_entry *e;
-	int len, offset;
-	int ret;
-	int addrlen;
-	struct kvec iov[1];
+	struct sockaddr_storage daddr;
+	int one = 1;
+	int result;
+	int addr_len;
+	struct socket *sock;
+
+	if (con->nodeid == 0) {
+		log_print("attempt to connect sock 0 foiled");
+		return;
+	}
 
 	mutex_lock(&con->sock_mutex);
-	if (test_and_set_bit(CF_INIT_PENDING, &con->flags))
-		goto unlock;
 
-	if (nodeid_to_addr(con->nodeid, NULL, (struct sockaddr *)&rem_addr,
-			   con->try_new_addr)) {
+	/* Some odd races can cause double-connects, ignore them */
+	if (con->retries++ > MAX_CONNECT_RETRIES)
+		goto out;
+
+	if (con->sock) {
+		log_print("node %d already connected.", con->nodeid);
+		goto out;
+	}
+
+	memset(&daddr, 0, sizeof(daddr));
+	result = nodeid_to_addr(con->nodeid, &daddr, NULL, true);
+	if (result < 0) {
 		log_print("no address for nodeid %d", con->nodeid);
-		goto unlock;
+		goto out;
 	}
-	base_con = nodeid2con(0, 0);
-	BUG_ON(base_con == NULL);
 
-	make_sockaddr(&rem_addr, dlm_config.ci_tcp_port, &addrlen);
+	/* Create a socket to communicate with */
+	result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
+				  SOCK_STREAM, IPPROTO_SCTP, &sock);
+	if (result < 0)
+		goto socket_err;
 
-	outmessage.msg_name = &rem_addr;
-	outmessage.msg_namelen = addrlen;
-	outmessage.msg_control = outcmsg;
-	outmessage.msg_controllen = sizeof(outcmsg);
-	outmessage.msg_flags = MSG_EOR;
+	sock->sk->sk_user_data = con;
+	con->rx_action = receive_from_sock;
+	con->connect_action = sctp_connect_to_sock;
+	add_sock(sock, con);
 
-	spin_lock(&con->writequeue_lock);
+	/* Bind to all addresses. */
+	if (sctp_bind_addrs(con, 0))
+		goto bind_err;
 
-	if (list_empty(&con->writequeue)) {
-		spin_unlock(&con->writequeue_lock);
-		log_print("writequeue empty for nodeid %d", con->nodeid);
-		goto unlock;
-	}
+	make_sockaddr(&daddr, dlm_config.ci_tcp_port, &addr_len);
 
-	e = list_first_entry(&con->writequeue, struct writequeue_entry, list);
-	len = e->len;
-	offset = e->offset;
+	log_print("connecting to %d", con->nodeid);
 
-	/* Send the first block off the write queue */
-	iov[0].iov_base = page_address(e->page)+offset;
-	iov[0].iov_len = len;
-	spin_unlock(&con->writequeue_lock);
+	/* Turn off Nagle's algorithm */
+	kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY, (char *)&one,
+			  sizeof(one));
 
-	if (rem_addr.ss_family == AF_INET) {
-		struct sockaddr_in *sin = (struct sockaddr_in *)&rem_addr;
-		log_print("Trying to connect to %pI4", &sin->sin_addr.s_addr);
-	} else {
-		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&rem_addr;
-		log_print("Trying to connect to %pI6", &sin6->sin6_addr);
-	}
+	result = sock->ops->connect(sock, (struct sockaddr *)&daddr, addr_len,
+				   O_NONBLOCK);
+	if (result == -EINPROGRESS)
+		result = 0;
+	if (result == 0)
+		goto out;
 
-	cmsg = CMSG_FIRSTHDR(&outmessage);
-	cmsg->cmsg_level = IPPROTO_SCTP;
-	cmsg->cmsg_type = SCTP_SNDRCV;
-	cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
-	sinfo = CMSG_DATA(cmsg);
-	memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo));
-	sinfo->sinfo_ppid = cpu_to_le32(con->nodeid);
-	outmessage.msg_controllen = cmsg->cmsg_len;
-	sinfo->sinfo_flags |= SCTP_ADDR_OVER;
 
-	ret = kernel_sendmsg(base_con->sock, &outmessage, iov, 1, len);
-	if (ret < 0) {
-		log_print("Send first packet to node %d failed: %d",
-			  con->nodeid, ret);
+bind_err:
+	con->sock = NULL;
+	sock_release(sock);
 
-		/* Try again later */
+socket_err:
+	/*
+	 * Some errors are fatal and this list might need adjusting. For other
+	 * errors we try again until the max number of retries is reached.
+	 */
+	if (result != -EHOSTUNREACH &&
+	    result != -ENETUNREACH &&
+	    result != -ENETDOWN &&
+	    result != -EINVAL &&
+	    result != -EPROTONOSUPPORT) {
+		log_print("connect %d try %d error %d", con->nodeid,
+			  con->retries, result);
+		mutex_unlock(&con->sock_mutex);
+		msleep(1000);
 		clear_bit(CF_CONNECT_PENDING, &con->flags);
-		clear_bit(CF_INIT_PENDING, &con->flags);
-	}
-	else {
-		spin_lock(&con->writequeue_lock);
-		writequeue_entry_complete(e, ret);
-		spin_unlock(&con->writequeue_lock);
+		lowcomms_connect_sock(con);
+		return;
 	}
 
-unlock:
+out:
 	mutex_unlock(&con->sock_mutex);
+	set_bit(CF_WRITE_PENDING, &con->flags);
 }
 
 /* Connect a new socket to its peer */
@@ -1236,11 +1149,13 @@ out_err:
 			  con->retries, result);
 		mutex_unlock(&con->sock_mutex);
 		msleep(1000);
+		clear_bit(CF_CONNECT_PENDING, &con->flags);
 		lowcomms_connect_sock(con);
 		return;
 	}
 out:
 	mutex_unlock(&con->sock_mutex);
+	set_bit(CF_WRITE_PENDING, &con->flags);
 	return;
 }
 
@@ -1325,37 +1240,11 @@ static void init_local(void)
 	}
 }
 
-/* Bind to an IP address. SCTP allows multiple address so it can do
-   multi-homing */
-static int add_sctp_bind_addr(struct connection *sctp_con,
-			      struct sockaddr_storage *addr,
-			      int addr_len, int num)
-{
-	int result = 0;
-
-	if (num == 1)
-		result = kernel_bind(sctp_con->sock,
-				     (struct sockaddr *) addr,
-				     addr_len);
-	else
-		result = kernel_setsockopt(sctp_con->sock, SOL_SCTP,
-					   SCTP_SOCKOPT_BINDX_ADD,
-					   (char *)addr, addr_len);
-
-	if (result < 0)
-		log_print("Can't bind to port %d addr number %d",
-			  dlm_config.ci_tcp_port, num);
-
-	return result;
-}
-
 /* Initialise SCTP socket and bind to all interfaces */
 static int sctp_listen_for_all(void)
 {
 	struct socket *sock = NULL;
-	struct sockaddr_storage localaddr;
-	struct sctp_event_subscribe subscribe;
-	int result = -EINVAL, num = 1, i, addr_len;
+	int result = -EINVAL;
 	struct connection *con = nodeid2con(0, GFP_NOFS);
 	int bufsize = NEEDED_RMEM;
 	int one = 1;
@@ -1366,33 +1255,17 @@ static int sctp_listen_for_all(void)
 	log_print("Using SCTP for communications");
 
 	result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
-				  SOCK_SEQPACKET, IPPROTO_SCTP, &sock);
+				  SOCK_STREAM, IPPROTO_SCTP, &sock);
 	if (result < 0) {
 		log_print("Can't create comms socket, check SCTP is loaded");
 		goto out;
 	}
 
-	/* Listen for events */
-	memset(&subscribe, 0, sizeof(subscribe));
-	subscribe.sctp_data_io_event = 1;
-	subscribe.sctp_association_event = 1;
-	subscribe.sctp_send_failure_event = 1;
-	subscribe.sctp_shutdown_event = 1;
-	subscribe.sctp_partial_delivery_event = 1;
-
 	result = kernel_setsockopt(sock, SOL_SOCKET, SO_RCVBUFFORCE,
 				 (char *)&bufsize, sizeof(bufsize));
 	if (result)
 		log_print("Error increasing buffer space on socket %d", result);
 
-	result = kernel_setsockopt(sock, SOL_SCTP, SCTP_EVENTS,
-				   (char *)&subscribe, sizeof(subscribe));
-	if (result < 0) {
-		log_print("Failed to set SCTP_EVENTS on socket: result=%d",
-			  result);
-		goto create_delsock;
-	}
-
 	result = kernel_setsockopt(sock, SOL_SCTP, SCTP_NODELAY, (char *)&one,
 				   sizeof(one));
 	if (result < 0)
@@ -1402,19 +1275,12 @@ static int sctp_listen_for_all(void)
 	sock->sk->sk_user_data = con;
 	con->sock = sock;
 	con->sock->sk->sk_data_ready = lowcomms_data_ready;
-	con->rx_action = receive_from_sock;
-	con->connect_action = sctp_init_assoc;
+	con->rx_action = sctp_accept_from_sock;
+	con->connect_action = sctp_connect_to_sock;
 
-	/* Bind to all interfaces. */
-	for (i = 0; i < dlm_local_count; i++) {
-		memcpy(&localaddr, dlm_local_addr[i], sizeof(localaddr));
-		make_sockaddr(&localaddr, dlm_config.ci_tcp_port, &addr_len);
-
-		result = add_sctp_bind_addr(con, &localaddr, addr_len, num);
-		if (result)
-			goto create_delsock;
-		++num;
-	}
+	/* Bind to all addresses. */
+	if (sctp_bind_addrs(con, dlm_config.ci_tcp_port))
+		goto create_delsock;
 
 	result = sock->ops->listen(sock, 5);
 	if (result < 0) {
@@ -1612,14 +1478,13 @@ out:
 
 send_error:
 	mutex_unlock(&con->sock_mutex);
-	close_connection(con, false);
+	close_connection(con, false, false, true);
 	lowcomms_connect_sock(con);
 	return;
 
 out_connect:
 	mutex_unlock(&con->sock_mutex);
-	if (!test_bit(CF_INIT_PENDING, &con->flags))
-		lowcomms_connect_sock(con);
+	lowcomms_connect_sock(con);
 }
 
 static void clean_one_writequeue(struct connection *con)
@@ -1644,15 +1509,9 @@ int dlm_lowcomms_close(int nodeid)
 	log_print("closing connection to node %d", nodeid);
 	con = nodeid2con(nodeid, 0);
 	if (con) {
-		clear_bit(CF_CONNECT_PENDING, &con->flags);
-		clear_bit(CF_WRITE_PENDING, &con->flags);
 		set_bit(CF_CLOSE, &con->flags);
-		if (cancel_work_sync(&con->swork))
-			log_print("canceled swork for node %d", nodeid);
-		if (cancel_work_sync(&con->rwork))
-			log_print("canceled rwork for node %d", nodeid);
+		close_connection(con, true, true, true);
 		clean_one_writequeue(con);
-		close_connection(con, true);
 	}
 
 	spin_lock(&dlm_node_addrs_spin);
@@ -1685,10 +1544,8 @@ static void process_send_sockets(struct work_struct *work)
 {
 	struct connection *con = container_of(work, struct connection, swork);
 
-	if (test_and_clear_bit(CF_CONNECT_PENDING, &con->flags)) {
+	if (test_and_clear_bit(CF_CONNECT_PENDING, &con->flags))
 		con->connect_action(con);
-		set_bit(CF_WRITE_PENDING, &con->flags);
-	}
 	if (test_and_clear_bit(CF_WRITE_PENDING, &con->flags))
 		send_to_sock(con);
 }
@@ -1735,7 +1592,7 @@ static void stop_conn(struct connection *con)
 
 static void free_conn(struct connection *con)
 {
-	close_connection(con, true);
+	close_connection(con, true, true, true);
 	if (con->othercon)
 		kmem_cache_free(con_cache, con->othercon);
 	hlist_del(&con->list);
@@ -1806,7 +1663,7 @@ fail_unlisten:
 	dlm_allow_conn = 0;
 	con = nodeid2con(0,0);
 	if (con) {
-		close_connection(con, false);
+		close_connection(con, false, true, true);
 		kmem_cache_free(con_cache, con);
 	}
 fail_destroy:
diff --git a/fs/dlm/user.c b/fs/dlm/user.c
index 75ecc0d3bc85..173b3873a4f4 100644
--- a/fs/dlm/user.c
+++ b/fs/dlm/user.c
@@ -782,6 +782,7 @@ static ssize_t device_read(struct file *file, char __user *buf, size_t count,
 	DECLARE_WAITQUEUE(wait, current);
 	struct dlm_callback cb;
 	int rv, resid, copy_lvb = 0;
+	int old_mode, new_mode;
 
 	if (count == sizeof(struct dlm_device_version)) {
 		rv = copy_version_to_user(buf, count);
@@ -838,6 +839,9 @@ static ssize_t device_read(struct file *file, char __user *buf, size_t count,
 
 	lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_cb_list);
 
+	/* rem_lkb_callback sets a new lkb_last_cast */
+	old_mode = lkb->lkb_last_cast.mode;
+
 	rv = dlm_rem_lkb_callback(lkb->lkb_resource->res_ls, lkb, &cb, &resid);
 	if (rv < 0) {
 		/* this shouldn't happen; lkb should have been removed from
@@ -861,9 +865,6 @@ static ssize_t device_read(struct file *file, char __user *buf, size_t count,
 	}
 
 	if (cb.flags & DLM_CB_CAST) {
-		int old_mode, new_mode;
-
-		old_mode = lkb->lkb_last_cast.mode;
 		new_mode = cb.mode;
 
 		if (!cb.sb_status && lkb->lkb_lksb->sb_lvbptr &&