[DLM] Consolidate transport protocols
This patch consolidates the TCP & SCTP protocols for the DLM into a single file
and makes it switchable at run-time (well, at least before the DLM actually
starts up!)
For RHEL5 this patch requires Neil Horman's patch that expands the in-kernel
socket API but that has already been twice ACKed so it should be OK.
The patch adds a new lowcomms.c file that replaces the existing lowcomms-sctp.c
& lowcomms-tcp.c files.
Signed-off-By: Patrick Caulfield <pcaulfie@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
new file mode 100644
index 0000000..76399b7
--- /dev/null
+++ b/fs/dlm/lowcomms.c
@@ -0,0 +1,1468 @@
+/******************************************************************************
+*******************************************************************************
+**
+** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
+** Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved.
+**
+** This copyrighted material is made available to anyone wishing to use,
+** modify, copy, or redistribute it subject to the terms and conditions
+** of the GNU General Public License v.2.
+**
+*******************************************************************************
+******************************************************************************/
+
+/*
+ * lowcomms.c
+ *
+ * This is the "low-level" comms layer.
+ *
+ * It is responsible for sending/receiving messages
+ * from other nodes in the cluster.
+ *
+ * Cluster nodes are referred to by their nodeids. nodeids are
+ * simply 32 bit numbers to the locking module - if they need to
+ * be expanded for the cluster infrastructure then that is it's
+ * responsibility. It is this layer's
+ * responsibility to resolve these into IP address or
+ * whatever it needs for inter-node communication.
+ *
+ * The comms level is two kernel threads that deal mainly with
+ * the receiving of messages from other nodes and passing them
+ * up to the mid-level comms layer (which understands the
+ * message format) for execution by the locking core, and
+ * a send thread which does all the setting up of connections
+ * to remote nodes and the sending of data. Threads are not allowed
+ * to send their own data because it may cause them to wait in times
+ * of high load. Also, this way, the sending thread can collect together
+ * messages bound for one node and send them in one block.
+ *
+ * lowcomms will choose to use wither TCP or SCTP as its transport layer
+ * depending on the configuration variable 'protocol'. This should be set
+ * to 0 (default) for TCP or 1 for SCTP. It shouldbe configured using a
+ * cluster-wide mechanism as it must be the same on all nodes of the cluster
+ * for the DLM to function.
+ *
+ */
+
+#include <asm/ioctls.h>
+#include <net/sock.h>
+#include <net/tcp.h>
+#include <linux/pagemap.h>
+#include <linux/idr.h>
+#include <linux/file.h>
+#include <linux/sctp.h>
+#include <net/sctp/user.h>
+
+#include "dlm_internal.h"
+#include "lowcomms.h"
+#include "midcomms.h"
+#include "config.h"
+
+#define NEEDED_RMEM (4*1024*1024)
+
+struct cbuf {
+ unsigned int base;
+ unsigned int len;
+ unsigned int mask;
+};
+
+static void cbuf_add(struct cbuf *cb, int n)
+{
+ cb->len += n;
+}
+
+static int cbuf_data(struct cbuf *cb)
+{
+ return ((cb->base + cb->len) & cb->mask);
+}
+
+static void cbuf_init(struct cbuf *cb, int size)
+{
+ cb->base = cb->len = 0;
+ cb->mask = size-1;
+}
+
+static void cbuf_eat(struct cbuf *cb, int n)
+{
+ cb->len -= n;
+ cb->base += n;
+ cb->base &= cb->mask;
+}
+
+static bool cbuf_empty(struct cbuf *cb)
+{
+ return cb->len == 0;
+}
+
+struct connection {
+ struct socket *sock; /* NULL if not connected */
+ uint32_t nodeid; /* So we know who we are in the list */
+ struct mutex sock_mutex;
+ unsigned long flags;
+#define CF_READ_PENDING 1
+#define CF_WRITE_PENDING 2
+#define CF_CONNECT_PENDING 3
+#define CF_INIT_PENDING 4
+#define CF_IS_OTHERCON 5
+ struct list_head writequeue; /* List of outgoing writequeue_entries */
+ spinlock_t writequeue_lock;
+ int (*rx_action) (struct connection *); /* What to do when active */
+ void (*connect_action) (struct connection *); /* What to do to connect */
+ struct page *rx_page;
+ struct cbuf cb;
+ int retries;
+#define MAX_CONNECT_RETRIES 3
+ int sctp_assoc;
+ struct connection *othercon;
+ struct work_struct rwork; /* Receive workqueue */
+ struct work_struct swork; /* Send workqueue */
+};
+#define sock2con(x) ((struct connection *)(x)->sk_user_data)
+
+/* An entry waiting to be sent */
+struct writequeue_entry {
+ struct list_head list;
+ struct page *page;
+ int offset;
+ int len;
+ int end;
+ int users;
+ struct connection *con;
+};
+
+static struct sockaddr_storage *dlm_local_addr[DLM_MAX_ADDR_COUNT];
+static int dlm_local_count;
+
+/* Work queues */
+static struct workqueue_struct *recv_workqueue;
+static struct workqueue_struct *send_workqueue;
+
+static DEFINE_IDR(connections_idr);
+static DECLARE_MUTEX(connections_lock);
+static int max_nodeid;
+static struct kmem_cache *con_cache;
+
+static void process_recv_sockets(struct work_struct *work);
+static void process_send_sockets(struct work_struct *work);
+
+/*
+ * If 'allocation' is zero then we don't attempt to create a new
+ * connection structure for this node.
+ */
+static struct connection *__nodeid2con(int nodeid, gfp_t alloc)
+{
+ struct connection *con = NULL;
+ int r;
+ int n;
+
+ con = idr_find(&connections_idr, nodeid);
+ if (con || !alloc)
+ return con;
+
+ r = idr_pre_get(&connections_idr, alloc);
+ if (!r)
+ return NULL;
+
+ con = kmem_cache_zalloc(con_cache, alloc);
+ if (!con)
+ return NULL;
+
+ r = idr_get_new_above(&connections_idr, con, nodeid, &n);
+ if (r) {
+ kmem_cache_free(con_cache, con);
+ return NULL;
+ }
+
+ if (n != nodeid) {
+ idr_remove(&connections_idr, n);
+ kmem_cache_free(con_cache, con);
+ return NULL;
+ }
+
+ con->nodeid = nodeid;
+ mutex_init(&con->sock_mutex);
+ INIT_LIST_HEAD(&con->writequeue);
+ spin_lock_init(&con->writequeue_lock);
+ INIT_WORK(&con->swork, process_send_sockets);
+ INIT_WORK(&con->rwork, process_recv_sockets);
+
+ /* Setup action pointers for child sockets */
+ if (con->nodeid) {
+ struct connection *zerocon = idr_find(&connections_idr, 0);
+
+ con->connect_action = zerocon->connect_action;
+ if (!con->rx_action)
+ con->rx_action = zerocon->rx_action;
+ }
+
+ if (nodeid > max_nodeid)
+ max_nodeid = nodeid;
+
+ return con;
+}
+
+static struct connection *nodeid2con(int nodeid, gfp_t allocation)
+{
+ struct connection *con;
+
+ down(&connections_lock);
+ con = __nodeid2con(nodeid, allocation);
+ up(&connections_lock);
+
+ 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;
+
+ down(&connections_lock);
+ for (i=0; i<max_nodeid; i++) {
+ con = __nodeid2con(i, 0);
+ if (con && con->sctp_assoc == assoc_id) {
+ up(&connections_lock);
+ return con;
+ }
+ }
+ up(&connections_lock);
+ return NULL;
+}
+
+static int nodeid_to_addr(int nodeid, struct sockaddr *retaddr)
+{
+ struct sockaddr_storage addr;
+ int error;
+
+ if (!dlm_local_count)
+ return -1;
+
+ error = dlm_nodeid_to_addr(nodeid, &addr);
+ if (error)
+ return error;
+
+ if (dlm_local_addr[0]->ss_family == AF_INET) {
+ struct sockaddr_in *in4 = (struct sockaddr_in *) &addr;
+ struct sockaddr_in *ret4 = (struct sockaddr_in *) retaddr;
+ ret4->sin_addr.s_addr = in4->sin_addr.s_addr;
+ } else {
+ struct sockaddr_in6 *in6 = (struct sockaddr_in6 *) &addr;
+ struct sockaddr_in6 *ret6 = (struct sockaddr_in6 *) retaddr;
+ memcpy(&ret6->sin6_addr, &in6->sin6_addr,
+ sizeof(in6->sin6_addr));
+ }
+
+ return 0;
+}
+
+/* Data available on socket or listen socket received a connect */
+static void lowcomms_data_ready(struct sock *sk, int count_unused)
+{
+ struct connection *con = sock2con(sk);
+ if (!test_and_set_bit(CF_READ_PENDING, &con->flags))
+ queue_work(recv_workqueue, &con->rwork);
+}
+
+static void lowcomms_write_space(struct sock *sk)
+{
+ struct connection *con = sock2con(sk);
+
+ if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags))
+ queue_work(send_workqueue, &con->swork);
+}
+
+static inline void lowcomms_connect_sock(struct connection *con)
+{
+ if (!test_and_set_bit(CF_CONNECT_PENDING, &con->flags))
+ queue_work(send_workqueue, &con->swork);
+}
+
+static void lowcomms_state_change(struct sock *sk)
+{
+ if (sk->sk_state == TCP_ESTABLISHED)
+ lowcomms_write_space(sk);
+}
+
+/* Make a socket active */
+static int add_sock(struct socket *sock, struct connection *con)
+{
+ con->sock = sock;
+
+ /* Install a data_ready callback */
+ con->sock->sk->sk_data_ready = lowcomms_data_ready;
+ con->sock->sk->sk_write_space = lowcomms_write_space;
+ con->sock->sk->sk_state_change = lowcomms_state_change;
+ con->sock->sk->sk_user_data = con;
+ return 0;
+}
+
+/* Add the port number to an IPv6 or 4 sockaddr and return the address
+ length */
+static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port,
+ int *addr_len)
+{
+ saddr->ss_family = dlm_local_addr[0]->ss_family;
+ if (saddr->ss_family == AF_INET) {
+ struct sockaddr_in *in4_addr = (struct sockaddr_in *)saddr;
+ in4_addr->sin_port = cpu_to_be16(port);
+ *addr_len = sizeof(struct sockaddr_in);
+ memset(&in4_addr->sin_zero, 0, sizeof(in4_addr->sin_zero));
+ } else {
+ struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)saddr;
+ in6_addr->sin6_port = cpu_to_be16(port);
+ *addr_len = sizeof(struct sockaddr_in6);
+ }
+}
+
+/* Close a remote connection and tidy up */
+static void close_connection(struct connection *con, bool and_other)
+{
+ 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);
+ }
+ if (con->rx_page) {
+ __free_page(con->rx_page);
+ con->rx_page = NULL;
+ }
+ con->retries = 0;
+ 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);
+}
+
+/* INIT failed but we don't know which node...
+ restart INIT on all pending nodes */
+static void sctp_init_failed(void)
+{
+ int i;
+ struct connection *con;
+
+ down(&connections_lock);
+ for (i=1; i<=max_nodeid; i++) {
+ con = __nodeid2con(i, 0);
+ if (!con)
+ continue;
+ con->sctp_assoc = 0;
+ if (test_and_clear_bit(CF_CONNECT_PENDING, &con->flags)) {
+ if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags)) {
+ queue_work(send_workqueue, &con->swork);
+ }
+ }
+ }
+ up(&connections_lock);
+}
+
+/* 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;
+
+ if (sn->sn_header.sn_type == 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;
+ struct file *file;
+ sctp_peeloff_arg_t parg;
+ int parglen = sizeof(parg);
+
+ /*
+ * 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 (dlm_addr_to_nodeid(&prim.ssp_addr, &nodeid)) {
+ int i;
+ unsigned char *b=(unsigned char *)&prim.ssp_addr;
+ log_print("reject connect from unknown addr");
+ for (i=0; i<sizeof(struct sockaddr_storage);i++)
+ printk("%02x ", b[i]);
+ printk("\n");
+ sctp_send_shutdown(prim.ssp_assoc_id);
+ return;
+ }
+
+ new_con = nodeid2con(nodeid, GFP_KERNEL);
+ if (!new_con)
+ return;
+
+ /* Peel off a new sock */
+ parg.associd = sn->sn_assoc_change.sac_assoc_id;
+ ret = kernel_getsockopt(con->sock, IPPROTO_SCTP, SCTP_SOCKOPT_PEELOFF,
+ (void *)&parg, &parglen);
+ if (ret < 0) {
+ log_print("Can't peel off a socket for connection %d to node %d: err=%d\n",
+ parg.associd, nodeid, ret);
+ return;
+ }
+
+ file = fget(parg.sd);
+ new_con->sock = SOCKET_I(file->f_dentry->d_inode);
+ add_sock(new_con->sock, new_con);
+ fput(file);
+ put_unused_fd(parg.sd);
+
+ log_print("got new/restarted association %d nodeid %d",
+ (int)sn->sn_assoc_change.sac_assoc_id, nodeid);
+
+ /* Send any pending writes */
+ clear_bit(CF_CONNECT_PENDING, &new_con->flags);
+ clear_bit(CF_INIT_PENDING, &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;
+
+ /* We don't know which INIT failed, so clear the PENDING flags
+ * on them all. if assoc_id is zero then it will then try
+ * again */
+
+ case SCTP_CANT_STR_ASSOC:
+ {
+ log_print("Can't start SCTP association - retrying");
+ sctp_init_failed();
+ }
+ 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);
+ }
+ }
+}
+
+/* Data received from remote end */
+static int receive_from_sock(struct connection *con)
+{
+ int ret = 0;
+ struct msghdr msg = {};
+ struct kvec iov[2];
+ unsigned len;
+ int r;
+ int call_again_soon = 0;
+ int nvec;
+ char incmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
+
+ mutex_lock(&con->sock_mutex);
+
+ if (con->sock == NULL) {
+ ret = -EAGAIN;
+ goto out_close;
+ }
+
+ if (con->rx_page == NULL) {
+ /*
+ * This doesn't need to be atomic, but I think it should
+ * improve performance if it is.
+ */
+ con->rx_page = alloc_page(GFP_ATOMIC);
+ if (con->rx_page == NULL)
+ goto out_resched;
+ 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.
+ */
+ iov[0].iov_len = con->cb.base - cbuf_data(&con->cb);
+ iov[0].iov_base = page_address(con->rx_page) + cbuf_data(&con->cb);
+ iov[1].iov_len = 0;
+ nvec = 1;
+
+ /*
+ * iov[1] is the bit of the circular buffer between the start of the
+ * buffer and the start of the currently used section (cb.base)
+ */
+ if (cbuf_data(&con->cb) >= con->cb.base) {
+ iov[0].iov_len = PAGE_CACHE_SIZE - cbuf_data(&con->cb);
+ iov[1].iov_len = con->cb.base;
+ iov[1].iov_base = page_address(con->rx_page);
+ nvec = 2;
+ }
+ len = iov[0].iov_len + iov[1].iov_len;
+
+ r = ret = kernel_recvmsg(con->sock, &msg, iov, nvec, len,
+ MSG_DONTWAIT | MSG_NOSIGNAL);
+ if (ret <= 0)
+ goto out_close;
+
+ /* Process SCTP notifications */
+ if (msg.msg_flags & MSG_NOTIFICATION) {
+ BUG_ON(con->nodeid != 0);
+ 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)
+ 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) {
+ printk(KERN_INFO "dlm: lowcomms: addr=%p, base=%u, len=%u, "
+ "iov_len=%u, iov_base[0]=%p, read=%d\n",
+ page_address(con->rx_page), con->cb.base, con->cb.len,
+ len, iov[0].iov_base, r);
+ }
+ if (ret < 0)
+ goto out_close;
+ cbuf_eat(&con->cb, ret);
+
+ if (cbuf_empty(&con->cb) && !call_again_soon) {
+ __free_page(con->rx_page);
+ con->rx_page = NULL;
+ }
+
+ if (call_again_soon)
+ goto out_resched;
+ mutex_unlock(&con->sock_mutex);
+ return 0;
+
+out_resched:
+ if (!test_and_set_bit(CF_READ_PENDING, &con->flags))
+ queue_work(recv_workqueue, &con->rwork);
+ mutex_unlock(&con->sock_mutex);
+ return -EAGAIN;
+
+out_close:
+ mutex_unlock(&con->sock_mutex);
+ if (ret != -EAGAIN && !test_bit(CF_IS_OTHERCON, &con->flags)) {
+ close_connection(con, false);
+ /* Reconnect when there is something to send */
+ }
+ /* Don't return success if we really got EOF */
+ if (ret == 0)
+ ret = -EAGAIN;
+
+ return ret;
+}
+
+/* Listening socket is busy, accept a connection */
+static int tcp_accept_from_sock(struct connection *con)
+{
+ int result;
+ struct sockaddr_storage peeraddr;
+ struct socket *newsock;
+ int len;
+ int nodeid;
+ struct connection *newcon;
+ struct connection *addcon;
+
+ memset(&peeraddr, 0, sizeof(peeraddr));
+ result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM,
+ IPPROTO_TCP, &newsock);
+ if (result < 0)
+ return -ENOMEM;
+
+ mutex_lock_nested(&con->sock_mutex, 0);
+
+ result = -ENOTCONN;
+ if (con->sock == NULL)
+ goto accept_err;
+
+ newsock->type = con->sock->type;
+ newsock->ops = con->sock->ops;
+
+ result = con->sock->ops->accept(con->sock, newsock, O_NONBLOCK);
+ if (result < 0)
+ goto accept_err;
+
+ /* Get the connected socket's peer */
+ memset(&peeraddr, 0, sizeof(peeraddr));
+ if (newsock->ops->getname(newsock, (struct sockaddr *)&peeraddr,
+ &len, 2)) {
+ result = -ECONNABORTED;
+ goto accept_err;
+ }
+
+ /* Get the new node's NODEID */
+ make_sockaddr(&peeraddr, 0, &len);
+ if (dlm_addr_to_nodeid(&peeraddr, &nodeid)) {
+ printk("dlm: connect from non cluster node\n");
+ sock_release(newsock);
+ mutex_unlock(&con->sock_mutex);
+ return -1;
+ }
+
+ log_print("got connection from %d", nodeid);
+
+ /* Check to see if we already have a connection to this node. This
+ * could happen if the two nodes initiate a connection at roughly
+ * the same time and the connections cross on the wire.
+ * In this case we store the incoming one in "othercon"
+ */
+ newcon = nodeid2con(nodeid, GFP_KERNEL);
+ if (!newcon) {
+ result = -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_KERNEL);
+ if (!othercon) {
+ printk("dlm: failed to allocate incoming socket\n");
+ mutex_unlock(&newcon->sock_mutex);
+ result = -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);
+ newcon->othercon = othercon;
+ }
+ othercon->sock = newsock;
+ newsock->sk->sk_user_data = othercon;
+ add_sock(newsock, othercon);
+ addcon = othercon;
+ }
+ else {
+ newsock->sk->sk_user_data = newcon;
+ newcon->rx_action = receive_from_sock;
+ add_sock(newsock, newcon);
+ addcon = newcon;
+ }
+
+ mutex_unlock(&newcon->sock_mutex);
+
+ /*
+ * Add it to the active queue in case we got data
+ * beween 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);
+ sock_release(newsock);
+
+ if (result != -EAGAIN)
+ printk("dlm: error accepting connection from node: %d\n", result);
+ return result;
+}
+
+static void free_entry(struct writequeue_entry *e)
+{
+ __free_page(e->page);
+ kfree(e);
+}
+
+/* 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)
+{
+ 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];
+
+ if (test_and_set_bit(CF_INIT_PENDING, &con->flags))
+ return;
+
+ if (con->retries++ > MAX_CONNECT_RETRIES)
+ return;
+
+ log_print("Initiating association with node %d", con->nodeid);
+
+ if (nodeid_to_addr(con->nodeid, (struct sockaddr *)&rem_addr)) {
+ log_print("no address for nodeid %d", con->nodeid);
+ return;
+ }
+ base_con = nodeid2con(0, 0);
+ BUG_ON(base_con == NULL);
+
+ make_sockaddr(&rem_addr, dlm_config.ci_tcp_port, &addrlen);
+
+ outmessage.msg_name = &rem_addr;
+ outmessage.msg_namelen = addrlen;
+ outmessage.msg_control = outcmsg;
+ outmessage.msg_controllen = sizeof(outcmsg);
+ outmessage.msg_flags = MSG_EOR;
+
+ spin_lock(&con->writequeue_lock);
+ e = list_entry(con->writequeue.next, struct writequeue_entry,
+ list);
+
+ BUG_ON((struct list_head *) e == &con->writequeue);
+
+ len = e->len;
+ offset = e->offset;
+ spin_unlock(&con->writequeue_lock);
+ kmap(e->page);
+
+ /* Send the first block off the write queue */
+ iov[0].iov_base = page_address(e->page)+offset;
+ iov[0].iov_len = len;
+
+ 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(dlm_our_nodeid());
+ outmessage.msg_controllen = cmsg->cmsg_len;
+
+ 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);
+
+ /* Try again later */
+ clear_bit(CF_CONNECT_PENDING, &con->flags);
+ clear_bit(CF_INIT_PENDING, &con->flags);
+ }
+ else {
+ spin_lock(&con->writequeue_lock);
+ e->offset += ret;
+ e->len -= ret;
+
+ if (e->len == 0 && e->users == 0) {
+ list_del(&e->list);
+ kunmap(e->page);
+ free_entry(e);
+ }
+ spin_unlock(&con->writequeue_lock);
+ }
+}
+
+/* Connect a new socket to its peer */
+static void tcp_connect_to_sock(struct connection *con)
+{
+ int result = -EHOSTUNREACH;
+ struct sockaddr_storage saddr;
+ 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 (con->retries++ > MAX_CONNECT_RETRIES)
+ goto out;
+
+ /* Some odd races can cause double-connects, ignore them */
+ if (con->sock) {
+ result = 0;
+ goto out;
+ }
+
+ /* Create a socket to communicate with */
+ result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM,
+ IPPROTO_TCP, &sock);
+ if (result < 0)
+ goto out_err;
+
+ memset(&saddr, 0, sizeof(saddr));
+ if (dlm_nodeid_to_addr(con->nodeid, &saddr))
+ goto out_err;
+
+ sock->sk->sk_user_data = con;
+ con->rx_action = receive_from_sock;
+ con->connect_action = tcp_connect_to_sock;
+ add_sock(sock, con);
+
+ make_sockaddr(&saddr, dlm_config.ci_tcp_port, &addr_len);
+
+ log_print("connecting to %d", con->nodeid);
+ result =
+ sock->ops->connect(sock, (struct sockaddr *)&saddr, addr_len,
+ O_NONBLOCK);
+ if (result == -EINPROGRESS)
+ result = 0;
+ if (result == 0)
+ goto out;
+
+out_err:
+ if (con->sock) {
+ sock_release(con->sock);
+ con->sock = NULL;
+ }
+ /*
+ * 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) {
+ lowcomms_connect_sock(con);
+ result = 0;
+ }
+out:
+ mutex_unlock(&con->sock_mutex);
+ return;
+}
+
+static struct socket *tcp_create_listen_sock(struct connection *con,
+ struct sockaddr_storage *saddr)
+{
+ struct socket *sock = NULL;
+ int result = 0;
+ int one = 1;
+ int addr_len;
+
+ if (dlm_local_addr[0]->ss_family == AF_INET)
+ addr_len = sizeof(struct sockaddr_in);
+ else
+ addr_len = sizeof(struct sockaddr_in6);
+
+ /* Create a socket to communicate with */
+ result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM, IPPROTO_TCP, &sock);
+ if (result < 0) {
+ printk("dlm: Can't create listening comms socket\n");
+ goto create_out;
+ }
+
+ result = kernel_setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,
+ (char *)&one, sizeof(one));
+
+ if (result < 0) {
+ printk("dlm: Failed to set SO_REUSEADDR on socket: result=%d\n",
+ result);
+ }
+ sock->sk->sk_user_data = con;
+ con->rx_action = tcp_accept_from_sock;
+ con->connect_action = tcp_connect_to_sock;
+ con->sock = sock;
+
+ /* Bind to our port */
+ make_sockaddr(saddr, dlm_config.ci_tcp_port, &addr_len);
+ result = sock->ops->bind(sock, (struct sockaddr *) saddr, addr_len);
+ if (result < 0) {
+ printk("dlm: Can't bind to port %d\n", dlm_config.ci_tcp_port);
+ sock_release(sock);
+ sock = NULL;
+ con->sock = NULL;
+ goto create_out;
+ }
+ result = kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
+ (char *)&one, sizeof(one));
+ if (result < 0) {
+ printk("dlm: Set keepalive failed: %d\n", result);
+ }
+
+ result = sock->ops->listen(sock, 5);
+ if (result < 0) {
+ printk("dlm: Can't listen on port %d\n", dlm_config.ci_tcp_port);
+ sock_release(sock);
+ sock = NULL;
+ goto create_out;
+ }
+
+create_out:
+ return sock;
+}
+
+/* Get local addresses */
+static void init_local(void)
+{
+ struct sockaddr_storage sas, *addr;
+ int i;
+
+ for (i = 0; i < DLM_MAX_ADDR_COUNT - 1; i++) {
+ if (dlm_our_addr(&sas, i))
+ break;
+
+ addr = kmalloc(sizeof(*addr), GFP_KERNEL);
+ if (!addr)
+ break;
+ memcpy(addr, &sas, sizeof(*addr));
+ dlm_local_addr[dlm_local_count++] = addr;
+ }
+}
+
+/* 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;
+ struct connection *con = nodeid2con(0, GFP_KERNEL);
+ int bufsize = NEEDED_RMEM;
+
+ if (!con)
+ return -ENOMEM;
+
+ log_print("Using SCTP for communications");
+
+ result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_SEQPACKET,
+ 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_RCVBUF,
+ (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;
+ }
+
+ /* Init con struct */
+ 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;
+
+ /* 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;
+ }
+
+ result = sock->ops->listen(sock, 5);
+ if (result < 0) {
+ log_print("Can't set socket listening");
+ goto create_delsock;
+ }
+
+ return 0;
+
+create_delsock:
+ sock_release(sock);
+ con->sock = NULL;
+out:
+ return result;
+}
+
+static int tcp_listen_for_all(void)
+{
+ struct socket *sock = NULL;
+ struct connection *con = nodeid2con(0, GFP_KERNEL);
+ int result = -EINVAL;
+
+ if (!con)
+ return -ENOMEM;
+
+ /* We don't support multi-homed hosts */
+ if (dlm_local_addr[1] != NULL) {
+ log_print("TCP protocol can't handle multi-homed hosts, try SCTP");
+ return -EINVAL;
+ }
+
+ log_print("Using TCP for communications");
+
+ set_bit(CF_IS_OTHERCON, &con->flags);
+
+ sock = tcp_create_listen_sock(con, dlm_local_addr[0]);
+ if (sock) {
+ add_sock(sock, con);
+ result = 0;
+ }
+ else {
+ result = -EADDRINUSE;
+ }
+
+ return result;
+}
+
+
+
+static struct writequeue_entry *new_writequeue_entry(struct connection *con,
+ gfp_t allocation)
+{
+ struct writequeue_entry *entry;
+
+ entry = kmalloc(sizeof(struct writequeue_entry), allocation);
+ if (!entry)
+ return NULL;
+
+ entry->page = alloc_page(allocation);
+ if (!entry->page) {
+ kfree(entry);
+ return NULL;
+ }
+
+ entry->offset = 0;
+ entry->len = 0;
+ entry->end = 0;
+ entry->users = 0;
+ entry->con = con;
+
+ return entry;
+}
+
+void *dlm_lowcomms_get_buffer(int nodeid, int len,
+ gfp_t allocation, char **ppc)
+{
+ struct connection *con;
+ struct writequeue_entry *e;
+ int offset = 0;
+ int users = 0;
+
+ con = nodeid2con(nodeid, allocation);
+ if (!con)
+ return NULL;
+
+ spin_lock(&con->writequeue_lock);
+ e = list_entry(con->writequeue.prev, struct writequeue_entry, list);
+ if ((&e->list == &con->writequeue) ||
+ (PAGE_CACHE_SIZE - e->end < len)) {
+ e = NULL;
+ } else {
+ offset = e->end;
+ e->end += len;
+ users = e->users++;
+ }
+ spin_unlock(&con->writequeue_lock);
+
+ if (e) {
+ got_one:
+ if (users == 0)
+ kmap(e->page);
+ *ppc = page_address(e->page) + offset;
+ return e;
+ }
+
+ e = new_writequeue_entry(con, allocation);
+ if (e) {
+ spin_lock(&con->writequeue_lock);
+ offset = e->end;
+ e->end += len;
+ users = e->users++;
+ list_add_tail(&e->list, &con->writequeue);
+ spin_unlock(&con->writequeue_lock);
+ goto got_one;
+ }
+ return NULL;
+}
+
+void dlm_lowcomms_commit_buffer(void *mh)
+{
+ struct writequeue_entry *e = (struct writequeue_entry *)mh;
+ struct connection *con = e->con;
+ int users;
+
+ spin_lock(&con->writequeue_lock);
+ users = --e->users;
+ if (users)
+ goto out;
+ e->len = e->end - e->offset;
+ kunmap(e->page);
+ spin_unlock(&con->writequeue_lock);
+
+ if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags)) {
+ queue_work(send_workqueue, &con->swork);
+ }
+ return;
+
+out:
+ spin_unlock(&con->writequeue_lock);
+ return;
+}
+
+/* Send a message */
+static void send_to_sock(struct connection *con)
+{
+ int ret = 0;
+ ssize_t(*sendpage) (struct socket *, struct page *, int, size_t, int);
+ const int msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL;
+ struct writequeue_entry *e;
+ int len, offset;
+
+ mutex_lock(&con->sock_mutex);
+ if (con->sock == NULL)
+ goto out_connect;
+
+ sendpage = con->sock->ops->sendpage;
+
+ spin_lock(&con->writequeue_lock);
+ for (;;) {
+ e = list_entry(con->writequeue.next, struct writequeue_entry,
+ list);
+ if ((struct list_head *) e == &con->writequeue)
+ break;
+
+ len = e->len;
+ offset = e->offset;
+ BUG_ON(len == 0 && e->users == 0);
+ spin_unlock(&con->writequeue_lock);
+ kmap(e->page);
+
+ ret = 0;
+ if (len) {
+ ret = sendpage(con->sock, e->page, offset, len,
+ msg_flags);
+ if (ret == -EAGAIN || ret == 0)
+ goto out;
+ if (ret <= 0)
+ goto send_error;
+ }
+ else {
+ /* Don't starve people filling buffers */
+ cond_resched();
+ }
+
+ spin_lock(&con->writequeue_lock);
+ e->offset += ret;
+ e->len -= ret;
+
+ if (e->len == 0 && e->users == 0) {
+ list_del(&e->list);
+ kunmap(e->page);
+ free_entry(e);
+ continue;
+ }
+ }
+ spin_unlock(&con->writequeue_lock);
+out:
+ mutex_unlock(&con->sock_mutex);
+ return;
+
+send_error:
+ mutex_unlock(&con->sock_mutex);
+ close_connection(con, false);
+ lowcomms_connect_sock(con);
+ return;
+
+out_connect:
+ mutex_unlock(&con->sock_mutex);
+ if (!test_bit(CF_INIT_PENDING, &con->flags))
+ lowcomms_connect_sock(con);
+ return;
+}
+
+static void clean_one_writequeue(struct connection *con)
+{
+ struct list_head *list;
+ struct list_head *temp;
+
+ spin_lock(&con->writequeue_lock);
+ list_for_each_safe(list, temp, &con->writequeue) {
+ struct writequeue_entry *e =
+ list_entry(list, struct writequeue_entry, list);
+ list_del(&e->list);
+ free_entry(e);
+ }
+ spin_unlock(&con->writequeue_lock);
+}
+
+/* Called from recovery when it knows that a node has
+ left the cluster */
+int dlm_lowcomms_close(int nodeid)
+{
+ struct connection *con;
+
+ log_print("closing connection to node %d", nodeid);
+ con = nodeid2con(nodeid, 0);
+ if (con) {
+ clean_one_writequeue(con);
+ close_connection(con, true);
+ }
+ return 0;
+}
+
+/* Receive workqueue function */
+static void process_recv_sockets(struct work_struct *work)
+{
+ struct connection *con = container_of(work, struct connection, rwork);
+ int err;
+
+ clear_bit(CF_READ_PENDING, &con->flags);
+ do {
+ err = con->rx_action(con);
+ } while (!err);
+}
+
+/* Send workqueue function */
+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)) {
+ con->connect_action(con);
+ }
+ clear_bit(CF_WRITE_PENDING, &con->flags);
+ send_to_sock(con);
+}
+
+
+/* Discard all entries on the write queues */
+static void clean_writequeues(void)
+{
+ int nodeid;
+
+ for (nodeid = 1; nodeid < max_nodeid; nodeid++) {
+ struct connection *con = nodeid2con(nodeid, 0);
+
+ if (con)
+ clean_one_writequeue(con);
+ }
+}
+
+static void work_stop(void)
+{
+ destroy_workqueue(recv_workqueue);
+ destroy_workqueue(send_workqueue);
+}
+
+static int work_start(void)
+{
+ int error;
+ recv_workqueue = create_workqueue("dlm_recv");
+ error = IS_ERR(recv_workqueue);
+ if (error) {
+ log_print("can't start dlm_recv %d", error);
+ return error;
+ }
+
+ send_workqueue = create_singlethread_workqueue("dlm_send");
+ error = IS_ERR(send_workqueue);
+ if (error) {
+ log_print("can't start dlm_send %d", error);
+ destroy_workqueue(recv_workqueue);
+ return error;
+ }
+
+ return 0;
+}
+
+void dlm_lowcomms_stop(void)
+{
+ int i;
+ struct connection *con;
+
+ /* Set all the flags to prevent any
+ socket activity.
+ */
+ down(&connections_lock);
+ for (i = 0; i < max_nodeid; i++) {
+ con = __nodeid2con(i, 0);
+ if (con)
+ con->flags |= 0xFF;
+ }
+ up(&connections_lock);
+
+ work_stop();
+
+ down(&connections_lock);
+ clean_writequeues();
+
+ for (i = 0; i < max_nodeid; i++) {
+ con = nodeid2con(i, 0);
+ if (con) {
+ close_connection(con, true);
+ if (con->othercon)
+ kmem_cache_free(con_cache, con->othercon);
+ kmem_cache_free(con_cache, con);
+ }
+ }
+ up(&connections_lock);
+ kmem_cache_destroy(con_cache);
+}
+
+int dlm_lowcomms_start(void)
+{
+ int error = -EINVAL;
+ struct connection *con;
+
+ init_local();
+ if (!dlm_local_count) {
+ log_print("no local IP address has been set");
+ goto out;
+ }
+
+ error = -ENOMEM;
+ con_cache = kmem_cache_create("dlm_conn", sizeof(struct connection),
+ __alignof__(struct connection), 0,
+ NULL, NULL);
+ if (!con_cache)
+ goto out;
+
+ /* Set some sysctl minima */
+ if (sysctl_rmem_max < NEEDED_RMEM)
+ sysctl_rmem_max = NEEDED_RMEM;
+
+ /* Start listening */
+ if (dlm_config.ci_protocol == 0)
+ error = tcp_listen_for_all();
+ else
+ error = sctp_listen_for_all();
+ if (error)
+ goto fail_unlisten;
+
+ error = work_start();
+ if (error)
+ goto fail_unlisten;
+
+ return 0;
+
+fail_unlisten:
+ con = nodeid2con(0,0);
+ if (con) {
+ close_connection(con, false);
+ kmem_cache_free(con_cache, con);
+ }
+ kmem_cache_destroy(con_cache);
+
+out:
+ return error;
+}