diff options
Diffstat (limited to 'fs/dlm/lowcomms.c')
| -rw-r--r-- | fs/dlm/lowcomms.c | 1238 |
1 files changed, 1238 insertions, 0 deletions
diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c new file mode 100644 index 000000000000..23f5ce12080b --- /dev/null +++ b/fs/dlm/lowcomms.c @@ -0,0 +1,1238 @@ +/****************************************************************************** +******************************************************************************* +** +** 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 *dlm_local_addr[DLM_MAX_ADDR_COUNT]; +static int dlm_local_count; +static int dlm_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 (!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; +} + +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 (!dlm_local_count) + return; + + if (!port) { + if (dlm_local_addr[0]->ss_family == AF_INET) { + local4_addr = (struct sockaddr_in *)dlm_local_addr[0]; + port = be16_to_cpu(local4_addr->sin_port); + } else { + local6_addr = (struct sockaddr_in6 *)dlm_local_addr[0]; + port = be16_to_cpu(local6_addr->sin6_port); + } + } + + saddr->ss_family = dlm_local_addr[0]->ss_family; + if (dlm_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; + + dlm_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)); + dlm_local_addr[dlm_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 (!dlm_local_count) { + init_local(); + if (!dlm_local_count) { + log_print("no local IP address has been set"); + goto out; + } + } + + 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; + + 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 < dlm_local_count; i++) { + memcpy(&localaddr, dlm_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(dlm_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(dlm_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); + len = e->len; + offset = e->offset; + BUG_ON(len == 0 && e->users == 0); + spin_unlock(&ni->writequeue_lock); + kmap(e->page); + + 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); + } + } +} + +int dlm_lowcomms_close(int nodeid) +{ + struct nodeinfo *ni; + + ni = nodeid2nodeinfo(nodeid, 0); + if (!ni) + return -1; + + spin_lock(&ni->lock); + if (ni->assoc_id) { + ni->assoc_id = 0; + /* Don't send shutdown here, sctp will just queue it + till the node comes back up! */ + } + spin_unlock(&ni->lock); + + clean_one_writequeue(ni); + clear_bit(NI_INIT_PENDING, &ni->flags); + return 0; +} + +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; + + 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); + spin_lock_init(&write_nodes_lock); + INIT_LIST_HEAD(&write_nodes); + init_rwsem(&nodeinfo_lock); + return 0; +} + +void dlm_lowcomms_exit(void) +{ + int i; + + for (i = 0; i < dlm_local_count; i++) + kfree(dlm_local_addr[i]); + dlm_local_count = 0; + dlm_local_nodeid = 0; +} + |