diff options
Diffstat (limited to 'fs/dlm/lowcomms.c')
| -rw-r--r-- | fs/dlm/lowcomms.c | 1468 |
1 files changed, 1468 insertions, 0 deletions
diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c new file mode 100644 index 00000000000..76399b7819b --- /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; +} |