[DLM] The core of the DLM for GFS2/CLVM
This is the core of the distributed lock manager which is required
to use GFS2 as a cluster filesystem. It is also used by CLVM and
can be used as a standalone lock manager independantly of either
of these two projects.
It implements VAX-style locking modes.
Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steve Whitehouse <swhiteho@redhat.com>
diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
new file mode 100644
index 0000000..09b0124
--- /dev/null
+++ b/fs/dlm/lowcomms.c
@@ -0,0 +1,1218 @@
+/******************************************************************************
+*******************************************************************************
+**
+** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
+** Copyright (C) 2004-2005 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.
+ *
+ * I don't see any problem with the recv thread executing the locking
+ * code on behalf of remote processes as the locking code is
+ * short, efficient and never (well, hardly ever) waits.
+ *
+ */
+
+#include <asm/ioctls.h>
+#include <net/sock.h>
+#include <net/tcp.h>
+#include <net/sctp/user.h>
+#include <linux/pagemap.h>
+#include <linux/socket.h>
+#include <linux/idr.h>
+
+#include "dlm_internal.h"
+#include "lowcomms.h"
+#include "config.h"
+#include "midcomms.h"
+
+static struct sockaddr_storage *local_addr[DLM_MAX_ADDR_COUNT];
+static int local_count;
+static int local_nodeid;
+
+/* One of these per connected node */
+
+#define NI_INIT_PENDING 1
+#define NI_WRITE_PENDING 2
+
+struct nodeinfo {
+ spinlock_t lock;
+ sctp_assoc_t assoc_id;
+ unsigned long flags;
+ struct list_head write_list; /* nodes with pending writes */
+ struct list_head writequeue; /* outgoing writequeue_entries */
+ spinlock_t writequeue_lock;
+ int nodeid;
+};
+
+static DEFINE_IDR(nodeinfo_idr);
+static struct rw_semaphore nodeinfo_lock;
+static int max_nodeid;
+
+struct cbuf {
+ unsigned base;
+ unsigned len;
+ unsigned mask;
+};
+
+/* Just the one of these, now. But this struct keeps
+ the connection-specific variables together */
+
+#define CF_READ_PENDING 1
+
+struct connection {
+ struct socket *sock;
+ unsigned long flags;
+ struct page *rx_page;
+ atomic_t waiting_requests;
+ struct cbuf cb;
+ int eagain_flag;
+};
+
+/* 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 nodeinfo *ni;
+};
+
+#define CBUF_ADD(cb, n) do { (cb)->len += n; } while(0)
+#define CBUF_EMPTY(cb) ((cb)->len == 0)
+#define CBUF_MAY_ADD(cb, n) (((cb)->len + (n)) < ((cb)->mask + 1))
+#define CBUF_DATA(cb) (((cb)->base + (cb)->len) & (cb)->mask)
+
+#define CBUF_INIT(cb, size) \
+do { \
+ (cb)->base = (cb)->len = 0; \
+ (cb)->mask = ((size)-1); \
+} while(0)
+
+#define CBUF_EAT(cb, n) \
+do { \
+ (cb)->len -= (n); \
+ (cb)->base += (n); \
+ (cb)->base &= (cb)->mask; \
+} while(0)
+
+
+/* List of nodes which have writes pending */
+static struct list_head write_nodes;
+static spinlock_t write_nodes_lock;
+
+/* Maximum number of incoming messages to process before
+ * doing a schedule()
+ */
+#define MAX_RX_MSG_COUNT 25
+
+/* Manage daemons */
+static struct task_struct *recv_task;
+static struct task_struct *send_task;
+static wait_queue_head_t lowcomms_recv_wait;
+static atomic_t accepting;
+
+/* The SCTP connection */
+static struct connection sctp_con;
+
+
+static int nodeid_to_addr(int nodeid, struct sockaddr *retaddr)
+{
+ struct sockaddr_storage addr;
+ int error;
+
+ if (!local_count)
+ return -1;
+
+ error = dlm_nodeid_to_addr(nodeid, &addr);
+ if (error)
+ return error;
+
+ if (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;
+}
+
+static struct nodeinfo *nodeid2nodeinfo(int nodeid, int alloc)
+{
+ struct nodeinfo *ni;
+ int r;
+ int n;
+
+ down_read(&nodeinfo_lock);
+ ni = idr_find(&nodeinfo_idr, nodeid);
+ up_read(&nodeinfo_lock);
+
+ if (!ni && alloc) {
+ down_write(&nodeinfo_lock);
+
+ ni = idr_find(&nodeinfo_idr, nodeid);
+ if (ni)
+ goto out_up;
+
+ r = idr_pre_get(&nodeinfo_idr, alloc);
+ if (!r)
+ goto out_up;
+
+ ni = kmalloc(sizeof(struct nodeinfo), alloc);
+ if (!ni)
+ goto out_up;
+
+ r = idr_get_new_above(&nodeinfo_idr, ni, nodeid, &n);
+ if (r) {
+ kfree(ni);
+ ni = NULL;
+ goto out_up;
+ }
+ if (n != nodeid) {
+ idr_remove(&nodeinfo_idr, n);
+ kfree(ni);
+ ni = NULL;
+ goto out_up;
+ }
+ memset(ni, 0, sizeof(struct nodeinfo));
+ spin_lock_init(&ni->lock);
+ INIT_LIST_HEAD(&ni->writequeue);
+ spin_lock_init(&ni->writequeue_lock);
+ ni->nodeid = nodeid;
+
+ if (nodeid > max_nodeid)
+ max_nodeid = nodeid;
+ out_up:
+ up_write(&nodeinfo_lock);
+ }
+
+ return ni;
+}
+
+/* Don't call this too often... */
+static struct nodeinfo *assoc2nodeinfo(sctp_assoc_t assoc)
+{
+ int i;
+ struct nodeinfo *ni;
+
+ for (i=1; i<=max_nodeid; i++) {
+ ni = nodeid2nodeinfo(i, 0);
+ if (ni && ni->assoc_id == assoc)
+ return ni;
+ }
+ return NULL;
+}
+
+/* Data or notification available on socket */
+static void lowcomms_data_ready(struct sock *sk, int count_unused)
+{
+ atomic_inc(&sctp_con.waiting_requests);
+ if (test_and_set_bit(CF_READ_PENDING, &sctp_con.flags))
+ return;
+
+ wake_up_interruptible(&lowcomms_recv_wait);
+}
+
+
+/* Add the port number to an IP6 or 4 sockaddr and return the address length.
+ Also padd out the struct with zeros to make comparisons meaningful */
+
+static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port,
+ int *addr_len)
+{
+ struct sockaddr_in *local4_addr;
+ struct sockaddr_in6 *local6_addr;
+
+ if (!local_count)
+ return;
+
+ if (!port) {
+ if (local_addr[0]->ss_family == AF_INET) {
+ local4_addr = (struct sockaddr_in *)local_addr[0];
+ port = be16_to_cpu(local4_addr->sin_port);
+ } else {
+ local6_addr = (struct sockaddr_in6 *)local_addr[0];
+ port = be16_to_cpu(local6_addr->sin6_port);
+ }
+ }
+
+ saddr->ss_family = local_addr[0]->ss_family;
+ if (local_addr[0]->ss_family == AF_INET) {
+ struct sockaddr_in *in4_addr = (struct sockaddr_in *)saddr;
+ in4_addr->sin_port = cpu_to_be16(port);
+ memset(&in4_addr->sin_zero, 0, sizeof(in4_addr->sin_zero));
+ memset(in4_addr+1, 0, sizeof(struct sockaddr_storage) -
+ sizeof(struct sockaddr_in));
+ *addr_len = sizeof(struct sockaddr_in);
+ } else {
+ struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)saddr;
+ in6_addr->sin6_port = cpu_to_be16(port);
+ memset(in6_addr+1, 0, sizeof(struct sockaddr_storage) -
+ sizeof(struct sockaddr_in6));
+ *addr_len = sizeof(struct sockaddr_in6);
+ }
+}
+
+/* Close the connection and tidy up */
+static void close_connection(void)
+{
+ if (sctp_con.sock) {
+ sock_release(sctp_con.sock);
+ sctp_con.sock = NULL;
+ }
+
+ if (sctp_con.rx_page) {
+ __free_page(sctp_con.rx_page);
+ sctp_con.rx_page = NULL;
+ }
+}
+
+/* We only send shutdown messages to nodes that are not part of the cluster */
+static void 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;
+
+ 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 = (struct sctp_sndrcvinfo *)CMSG_DATA(cmsg);
+ memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo));
+
+ sinfo->sinfo_flags |= MSG_EOF;
+ sinfo->sinfo_assoc_id = associd;
+
+ ret = kernel_sendmsg(sctp_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 init_failed(void)
+{
+ int i;
+ struct nodeinfo *ni;
+
+ for (i=1; i<=max_nodeid; i++) {
+ ni = nodeid2nodeinfo(i, 0);
+ if (!ni)
+ continue;
+
+ if (test_and_clear_bit(NI_INIT_PENDING, &ni->flags)) {
+ ni->assoc_id = 0;
+ if (!test_and_set_bit(NI_WRITE_PENDING, &ni->flags)) {
+ spin_lock_bh(&write_nodes_lock);
+ list_add_tail(&ni->write_list, &write_nodes);
+ spin_unlock_bh(&write_nodes_lock);
+ }
+ }
+ }
+ wake_up_process(send_task);
+}
+
+/* Something happened to an association */
+static void process_sctp_notification(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;
+ mm_segment_t fs;
+ int nodeid;
+ int prim_len, ret;
+ int addr_len;
+ struct nodeinfo *ni;
+
+ /* This seems to happen when we received a connection
+ * too early... or something... anyway, it happens but
+ * we always seem to get a real message too, see
+ * receive_from_sock */
+
+ 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);
+ 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;
+
+ fs = get_fs();
+ set_fs(get_ds());
+ ret = sctp_con.sock->ops->getsockopt(sctp_con.sock,
+ IPPROTO_SCTP, SCTP_PRIMARY_ADDR,
+ (char*)&prim, &prim_len);
+ set_fs(fs);
+ if (ret < 0) {
+ struct nodeinfo *ni;
+
+ log_print("getsockopt/sctp_primary_addr on "
+ "new assoc %d failed : %d",
+ (int)sn->sn_assoc_change.sac_assoc_id, ret);
+
+ /* Retry INIT later */
+ ni = assoc2nodeinfo(sn->sn_assoc_change.sac_assoc_id);
+ if (ni)
+ clear_bit(NI_INIT_PENDING, &ni->flags);
+ return;
+ }
+ make_sockaddr(&prim.ssp_addr, 0, &addr_len);
+ if (dlm_addr_to_nodeid(&prim.ssp_addr, &nodeid)) {
+ log_print("reject connect from unknown addr");
+ send_shutdown(prim.ssp_assoc_id);
+ return;
+ }
+
+ ni = nodeid2nodeinfo(nodeid, GFP_KERNEL);
+ if (!ni)
+ return;
+
+ /* Save the assoc ID */
+ spin_lock(&ni->lock);
+ ni->assoc_id = sn->sn_assoc_change.sac_assoc_id;
+ spin_unlock(&ni->lock);
+
+ log_print("got new/restarted association %d nodeid %d",
+ (int)sn->sn_assoc_change.sac_assoc_id, nodeid);
+
+ /* Send any pending writes */
+ clear_bit(NI_INIT_PENDING, &ni->flags);
+ if (!test_and_set_bit(NI_WRITE_PENDING, &ni->flags)) {
+ spin_lock_bh(&write_nodes_lock);
+ list_add_tail(&ni->write_list, &write_nodes);
+ spin_unlock_bh(&write_nodes_lock);
+ }
+ wake_up_process(send_task);
+ }
+ break;
+
+ case SCTP_COMM_LOST:
+ case SCTP_SHUTDOWN_COMP:
+ {
+ struct nodeinfo *ni;
+
+ ni = assoc2nodeinfo(sn->sn_assoc_change.sac_assoc_id);
+ if (ni) {
+ spin_lock(&ni->lock);
+ ni->assoc_id = 0;
+ spin_unlock(&ni->lock);
+ }
+ }
+ 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");
+ 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(void)
+{
+ int ret = 0;
+ struct msghdr msg;
+ struct kvec iov[2];
+ unsigned len;
+ int r;
+ struct sctp_sndrcvinfo *sinfo;
+ struct cmsghdr *cmsg;
+ struct nodeinfo *ni;
+
+ /* These two are marginally too big for stack allocation, but this
+ * function is (currently) only called by dlm_recvd so static should be
+ * OK.
+ */
+ static struct sockaddr_storage msgname;
+ static char incmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
+
+ if (sctp_con.sock == NULL)
+ goto out;
+
+ if (sctp_con.rx_page == NULL) {
+ /*
+ * This doesn't need to be atomic, but I think it should
+ * improve performance if it is.
+ */
+ sctp_con.rx_page = alloc_page(GFP_ATOMIC);
+ if (sctp_con.rx_page == NULL)
+ goto out_resched;
+ CBUF_INIT(&sctp_con.cb, PAGE_CACHE_SIZE);
+ }
+
+ memset(&incmsg, 0, sizeof(incmsg));
+ memset(&msgname, 0, sizeof(msgname));
+
+ memset(incmsg, 0, sizeof(incmsg));
+ msg.msg_name = &msgname;
+ msg.msg_namelen = sizeof(msgname);
+ msg.msg_flags = 0;
+ msg.msg_control = incmsg;
+ msg.msg_controllen = sizeof(incmsg);
+
+ /* I don't see why this circular buffer stuff is necessary for SCTP
+ * which is a packet-based protocol, but the whole thing breaks under
+ * load without it! The overhead is minimal (and is in the TCP lowcomms
+ * anyway, of course) so I'll leave it in until I can figure out what's
+ * really happening.
+ */
+
+ /*
+ * 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 = sctp_con.cb.base - CBUF_DATA(&sctp_con.cb);
+ iov[0].iov_base = page_address(sctp_con.rx_page) +
+ CBUF_DATA(&sctp_con.cb);
+ iov[1].iov_len = 0;
+
+ /*
+ * 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(&sctp_con.cb) >= sctp_con.cb.base) {
+ iov[0].iov_len = PAGE_CACHE_SIZE - CBUF_DATA(&sctp_con.cb);
+ iov[1].iov_len = sctp_con.cb.base;
+ iov[1].iov_base = page_address(sctp_con.rx_page);
+ msg.msg_iovlen = 2;
+ }
+ len = iov[0].iov_len + iov[1].iov_len;
+
+ r = ret = kernel_recvmsg(sctp_con.sock, &msg, iov, 1, len,
+ MSG_NOSIGNAL | MSG_DONTWAIT);
+ if (ret <= 0)
+ goto out_close;
+
+ msg.msg_control = incmsg;
+ msg.msg_controllen = sizeof(incmsg);
+ cmsg = CMSG_FIRSTHDR(&msg);
+ sinfo = (struct sctp_sndrcvinfo *)CMSG_DATA(cmsg);
+
+ if (msg.msg_flags & MSG_NOTIFICATION) {
+ process_sctp_notification(&msg, page_address(sctp_con.rx_page));
+ return 0;
+ }
+
+ /* Is this a new association ? */
+ ni = nodeid2nodeinfo(le32_to_cpu(sinfo->sinfo_ppid), GFP_KERNEL);
+ if (ni) {
+ ni->assoc_id = sinfo->sinfo_assoc_id;
+ if (test_and_clear_bit(NI_INIT_PENDING, &ni->flags)) {
+
+ if (!test_and_set_bit(NI_WRITE_PENDING, &ni->flags)) {
+ spin_lock_bh(&write_nodes_lock);
+ list_add_tail(&ni->write_list, &write_nodes);
+ spin_unlock_bh(&write_nodes_lock);
+ }
+ wake_up_process(send_task);
+ }
+ }
+
+ /* INIT sends a message with length of 1 - ignore it */
+ if (r == 1)
+ return 0;
+
+ CBUF_ADD(&sctp_con.cb, ret);
+ ret = dlm_process_incoming_buffer(cpu_to_le32(sinfo->sinfo_ppid),
+ page_address(sctp_con.rx_page),
+ sctp_con.cb.base, sctp_con.cb.len,
+ PAGE_CACHE_SIZE);
+ if (ret < 0)
+ goto out_close;
+ CBUF_EAT(&sctp_con.cb, ret);
+
+ out:
+ ret = 0;
+ goto out_ret;
+
+ out_resched:
+ lowcomms_data_ready(sctp_con.sock->sk, 0);
+ ret = 0;
+ schedule();
+ goto out_ret;
+
+ out_close:
+ if (ret != -EAGAIN)
+ log_print("error reading from sctp socket: %d", ret);
+ out_ret:
+ return ret;
+}
+
+/* Bind to an IP address. SCTP allows multiple address so it can do multi-homing */
+static int add_bind_addr(struct sockaddr_storage *addr, int addr_len, int num)
+{
+ mm_segment_t fs;
+ int result = 0;
+
+ fs = get_fs();
+ set_fs(get_ds());
+ if (num == 1)
+ result = sctp_con.sock->ops->bind(sctp_con.sock,
+ (struct sockaddr *) addr, addr_len);
+ else
+ result = sctp_con.sock->ops->setsockopt(sctp_con.sock, SOL_SCTP,
+ SCTP_SOCKOPT_BINDX_ADD, (char *)addr, addr_len);
+ set_fs(fs);
+
+ if (result < 0)
+ log_print("Can't bind to port %d addr number %d",
+ dlm_config.tcp_port, num);
+
+ return result;
+}
+
+static void init_local(void)
+{
+ struct sockaddr_storage sas, *addr;
+ int i;
+
+ local_nodeid = dlm_our_nodeid();
+
+ 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));
+ local_addr[local_count++] = addr;
+ }
+}
+
+/* Initialise SCTP socket and bind to all interfaces */
+static int init_sock(void)
+{
+ mm_segment_t fs;
+ struct socket *sock = NULL;
+ struct sockaddr_storage localaddr;
+ struct sctp_event_subscribe subscribe;
+ int result = -EINVAL, num = 1, i, addr_len;
+
+ if (!local_count) {
+ init_local();
+ if (!local_count) {
+ log_print("no local IP address has been set");
+ goto out;
+ }
+ }
+
+ result = sock_create_kern(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;
+
+ fs = get_fs();
+ set_fs(get_ds());
+ result = sock->ops->setsockopt(sock, SOL_SCTP, SCTP_EVENTS,
+ (char *)&subscribe, sizeof(subscribe));
+ set_fs(fs);
+
+ 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 = &sctp_con;
+ sctp_con.sock = sock;
+ sctp_con.sock->sk->sk_data_ready = lowcomms_data_ready;
+
+ /* Bind to all interfaces. */
+ for (i = 0; i < local_count; i++) {
+ memcpy(&localaddr, local_addr[i], sizeof(localaddr));
+ make_sockaddr(&localaddr, dlm_config.tcp_port, &addr_len);
+
+ result = add_bind_addr(&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);
+ sctp_con.sock = NULL;
+ out:
+ return result;
+}
+
+
+static struct writequeue_entry *new_writequeue_entry(int 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;
+
+ return entry;
+}
+
+void *dlm_lowcomms_get_buffer(int nodeid, int len, int allocation, char **ppc)
+{
+ struct writequeue_entry *e;
+ int offset = 0;
+ int users = 0;
+ struct nodeinfo *ni;
+
+ if (!atomic_read(&accepting))
+ return NULL;
+
+ ni = nodeid2nodeinfo(nodeid, allocation);
+ if (!ni)
+ return NULL;
+
+ spin_lock(&ni->writequeue_lock);
+ e = list_entry(ni->writequeue.prev, struct writequeue_entry, list);
+ if (((struct list_head *) e == &ni->writequeue) ||
+ (PAGE_CACHE_SIZE - e->end < len)) {
+ e = NULL;
+ } else {
+ offset = e->end;
+ e->end += len;
+ users = e->users++;
+ }
+ spin_unlock(&ni->writequeue_lock);
+
+ if (e) {
+ got_one:
+ if (users == 0)
+ kmap(e->page);
+ *ppc = page_address(e->page) + offset;
+ return e;
+ }
+
+ e = new_writequeue_entry(allocation);
+ if (e) {
+ spin_lock(&ni->writequeue_lock);
+ offset = e->end;
+ e->end += len;
+ e->ni = ni;
+ users = e->users++;
+ list_add_tail(&e->list, &ni->writequeue);
+ spin_unlock(&ni->writequeue_lock);
+ goto got_one;
+ }
+ return NULL;
+}
+
+void dlm_lowcomms_commit_buffer(void *arg)
+{
+ struct writequeue_entry *e = (struct writequeue_entry *) arg;
+ int users;
+ struct nodeinfo *ni = e->ni;
+
+ if (!atomic_read(&accepting))
+ return;
+
+ spin_lock(&ni->writequeue_lock);
+ users = --e->users;
+ if (users)
+ goto out;
+ e->len = e->end - e->offset;
+ kunmap(e->page);
+ spin_unlock(&ni->writequeue_lock);
+
+ if (!test_and_set_bit(NI_WRITE_PENDING, &ni->flags)) {
+ spin_lock_bh(&write_nodes_lock);
+ list_add_tail(&ni->write_list, &write_nodes);
+ spin_unlock_bh(&write_nodes_lock);
+ wake_up_process(send_task);
+ }
+ return;
+
+ out:
+ spin_unlock(&ni->writequeue_lock);
+ return;
+}
+
+static void free_entry(struct writequeue_entry *e)
+{
+ __free_page(e->page);
+ kfree(e);
+}
+
+/* Initiate an SCTP association. In theory we could just use sendmsg() on
+ the first IP address and it should work, but this allows us to set up the
+ association before sending any valuable data that we can't afford to lose.
+ It also keeps the send path clean as it can now always use the association ID */
+static void initiate_association(int nodeid)
+{
+ struct sockaddr_storage rem_addr;
+ static char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
+ struct msghdr outmessage;
+ struct cmsghdr *cmsg;
+ struct sctp_sndrcvinfo *sinfo;
+ int ret;
+ int addrlen;
+ char buf[1];
+ struct kvec iov[1];
+ struct nodeinfo *ni;
+
+ log_print("Initiating association with node %d", nodeid);
+
+ ni = nodeid2nodeinfo(nodeid, GFP_KERNEL);
+ if (!ni)
+ return;
+
+ if (nodeid_to_addr(nodeid, (struct sockaddr *)&rem_addr)) {
+ log_print("no address for nodeid %d", nodeid);
+ return;
+ }
+
+ make_sockaddr(&rem_addr, dlm_config.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;
+
+ iov[0].iov_base = buf;
+ iov[0].iov_len = 1;
+
+ /* Real INIT messages seem to cause trouble. Just send a 1 byte message
+ we can afford to lose */
+ cmsg = CMSG_FIRSTHDR(&outmessage);
+ cmsg->cmsg_level = IPPROTO_SCTP;
+ cmsg->cmsg_type = SCTP_SNDRCV;
+ cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
+ sinfo = (struct sctp_sndrcvinfo *)CMSG_DATA(cmsg);
+ memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo));
+ sinfo->sinfo_ppid = cpu_to_le32(local_nodeid);
+
+ outmessage.msg_controllen = cmsg->cmsg_len;
+ ret = kernel_sendmsg(sctp_con.sock, &outmessage, iov, 1, 1);
+ if (ret < 0) {
+ log_print("send INIT to node failed: %d", ret);
+ /* Try again later */
+ clear_bit(NI_INIT_PENDING, &ni->flags);
+ }
+}
+
+/* Send a message */
+static int send_to_sock(struct nodeinfo *ni)
+{
+ int ret = 0;
+ struct writequeue_entry *e;
+ int len, offset;
+ struct msghdr outmsg;
+ static char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
+ struct cmsghdr *cmsg;
+ struct sctp_sndrcvinfo *sinfo;
+ struct kvec iov;
+
+ /* See if we need to init an association before we start
+ sending precious messages */
+ spin_lock(&ni->lock);
+ if (!ni->assoc_id && !test_and_set_bit(NI_INIT_PENDING, &ni->flags)) {
+ spin_unlock(&ni->lock);
+ initiate_association(ni->nodeid);
+ return 0;
+ }
+ spin_unlock(&ni->lock);
+
+ outmsg.msg_name = NULL; /* We use assoc_id */
+ outmsg.msg_namelen = 0;
+ outmsg.msg_control = outcmsg;
+ outmsg.msg_controllen = sizeof(outcmsg);
+ outmsg.msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL | MSG_EOR;
+
+ cmsg = CMSG_FIRSTHDR(&outmsg);
+ cmsg->cmsg_level = IPPROTO_SCTP;
+ cmsg->cmsg_type = SCTP_SNDRCV;
+ cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
+ sinfo = (struct sctp_sndrcvinfo *)CMSG_DATA(cmsg);
+ memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo));
+ sinfo->sinfo_ppid = cpu_to_le32(local_nodeid);
+ sinfo->sinfo_assoc_id = ni->assoc_id;
+ outmsg.msg_controllen = cmsg->cmsg_len;
+
+ spin_lock(&ni->writequeue_lock);
+ for (;;) {
+ if (list_empty(&ni->writequeue))
+ break;
+ e = list_entry(ni->writequeue.next, struct writequeue_entry,
+ list);
+ kmap(e->page);
+ len = e->len;
+ offset = e->offset;
+ BUG_ON(len == 0 && e->users == 0);
+ spin_unlock(&ni->writequeue_lock);
+
+ ret = 0;
+ if (len) {
+ iov.iov_base = page_address(e->page)+offset;
+ iov.iov_len = len;
+
+ ret = kernel_sendmsg(sctp_con.sock, &outmsg, &iov, 1,
+ len);
+ if (ret == -EAGAIN) {
+ sctp_con.eagain_flag = 1;
+ goto out;
+ } else if (ret < 0)
+ goto send_error;
+ } else {
+ /* Don't starve people filling buffers */
+ schedule();
+ }
+
+ spin_lock(&ni->writequeue_lock);
+ e->offset += ret;
+ e->len -= ret;
+
+ if (e->len == 0 && e->users == 0) {
+ list_del(&e->list);
+ free_entry(e);
+ continue;
+ }
+ }
+ spin_unlock(&ni->writequeue_lock);
+ out:
+ return ret;
+
+ send_error:
+ log_print("Error sending to node %d %d", ni->nodeid, ret);
+ spin_lock(&ni->lock);
+ if (!test_and_set_bit(NI_INIT_PENDING, &ni->flags)) {
+ ni->assoc_id = 0;
+ spin_unlock(&ni->lock);
+ initiate_association(ni->nodeid);
+ } else
+ spin_unlock(&ni->lock);
+
+ return ret;
+}
+
+/* Try to send any messages that are pending */
+static void process_output_queue(void)
+{
+ struct list_head *list;
+ struct list_head *temp;
+
+ spin_lock_bh(&write_nodes_lock);
+ list_for_each_safe(list, temp, &write_nodes) {
+ struct nodeinfo *ni =
+ list_entry(list, struct nodeinfo, write_list);
+ clear_bit(NI_WRITE_PENDING, &ni->flags);
+ list_del(&ni->write_list);
+
+ spin_unlock_bh(&write_nodes_lock);
+
+ send_to_sock(ni);
+ spin_lock_bh(&write_nodes_lock);
+ }
+ spin_unlock_bh(&write_nodes_lock);
+}
+
+/* Called after we've had -EAGAIN and been woken up */
+static void refill_write_queue(void)
+{
+ int i;
+
+ for (i=1; i<=max_nodeid; i++) {
+ struct nodeinfo *ni = nodeid2nodeinfo(i, 0);
+
+ if (ni) {
+ if (!test_and_set_bit(NI_WRITE_PENDING, &ni->flags)) {
+ spin_lock_bh(&write_nodes_lock);
+ list_add_tail(&ni->write_list, &write_nodes);
+ spin_unlock_bh(&write_nodes_lock);
+ }
+ }
+ }
+}
+
+static void clean_one_writequeue(struct nodeinfo *ni)
+{
+ struct list_head *list;
+ struct list_head *temp;
+
+ spin_lock(&ni->writequeue_lock);
+ list_for_each_safe(list, temp, &ni->writequeue) {
+ struct writequeue_entry *e =
+ list_entry(list, struct writequeue_entry, list);
+ list_del(&e->list);
+ free_entry(e);
+ }
+ spin_unlock(&ni->writequeue_lock);
+}
+
+static void clean_writequeues(void)
+{
+ int i;
+
+ for (i=1; i<=max_nodeid; i++) {
+ struct nodeinfo *ni = nodeid2nodeinfo(i, 0);
+ if (ni)
+ clean_one_writequeue(ni);
+ }
+}
+
+
+static void dealloc_nodeinfo(void)
+{
+ int i;
+
+ for (i=1; i<=max_nodeid; i++) {
+ struct nodeinfo *ni = nodeid2nodeinfo(i, 0);
+ if (ni) {
+ idr_remove(&nodeinfo_idr, i);
+ kfree(ni);
+ }
+ }
+}
+
+static int write_list_empty(void)
+{
+ int status;
+
+ spin_lock_bh(&write_nodes_lock);
+ status = list_empty(&write_nodes);
+ spin_unlock_bh(&write_nodes_lock);
+
+ return status;
+}
+
+static int dlm_recvd(void *data)
+{
+ DECLARE_WAITQUEUE(wait, current);
+
+ while (!kthread_should_stop()) {
+ int count = 0;
+
+ set_current_state(TASK_INTERRUPTIBLE);
+ add_wait_queue(&lowcomms_recv_wait, &wait);
+ if (!test_bit(CF_READ_PENDING, &sctp_con.flags))
+ schedule();
+ remove_wait_queue(&lowcomms_recv_wait, &wait);
+ set_current_state(TASK_RUNNING);
+
+ if (test_and_clear_bit(CF_READ_PENDING, &sctp_con.flags)) {
+ int ret;
+
+ do {
+ ret = receive_from_sock();
+
+ /* Don't starve out everyone else */
+ if (++count >= MAX_RX_MSG_COUNT) {
+ schedule();
+ count = 0;
+ }
+ } while (!kthread_should_stop() && ret >=0);
+ }
+ schedule();
+ }
+
+ return 0;
+}
+
+static int dlm_sendd(void *data)
+{
+ DECLARE_WAITQUEUE(wait, current);
+
+ add_wait_queue(sctp_con.sock->sk->sk_sleep, &wait);
+
+ while (!kthread_should_stop()) {
+ set_current_state(TASK_INTERRUPTIBLE);
+ if (write_list_empty())
+ schedule();
+ set_current_state(TASK_RUNNING);
+
+ if (sctp_con.eagain_flag) {
+ sctp_con.eagain_flag = 0;
+ refill_write_queue();
+ }
+ process_output_queue();
+ }
+
+ remove_wait_queue(sctp_con.sock->sk->sk_sleep, &wait);
+
+ return 0;
+}
+
+static void daemons_stop(void)
+{
+ kthread_stop(recv_task);
+ kthread_stop(send_task);
+}
+
+static int daemons_start(void)
+{
+ struct task_struct *p;
+ int error;
+
+ p = kthread_run(dlm_recvd, NULL, "dlm_recvd");
+ error = IS_ERR(p);
+ if (error) {
+ log_print("can't start dlm_recvd %d", error);
+ return error;
+ }
+ recv_task = p;
+
+ p = kthread_run(dlm_sendd, NULL, "dlm_sendd");
+ error = IS_ERR(p);
+ if (error) {
+ log_print("can't start dlm_sendd %d", error);
+ kthread_stop(recv_task);
+ return error;
+ }
+ send_task = p;
+
+ return 0;
+}
+
+/*
+ * This is quite likely to sleep...
+ */
+int dlm_lowcomms_start(void)
+{
+ int error;
+
+ spin_lock_init(&write_nodes_lock);
+ INIT_LIST_HEAD(&write_nodes);
+ init_rwsem(&nodeinfo_lock);
+
+ error = init_sock();
+ if (error)
+ goto fail_sock;
+ error = daemons_start();
+ if (error)
+ goto fail_sock;
+ atomic_set(&accepting, 1);
+ return 0;
+
+ fail_sock:
+ close_connection();
+ return error;
+}
+
+/* Set all the activity flags to prevent any socket activity. */
+
+void dlm_lowcomms_stop(void)
+{
+ atomic_set(&accepting, 0);
+ sctp_con.flags = 0x7;
+ daemons_stop();
+ clean_writequeues();
+ close_connection();
+ dealloc_nodeinfo();
+ max_nodeid = 0;
+}
+
+int dlm_lowcomms_init(void)
+{
+ init_waitqueue_head(&lowcomms_recv_wait);
+ return 0;
+}
+
+void dlm_lowcomms_exit(void)
+{
+ int i;
+
+ for (i = 0; i < local_count; i++)
+ kfree(local_addr[i]);
+ local_count = 0;
+ local_nodeid = 0;
+}
+