linux/fs/dlm/lowcomms.c
<<
>>
Prefs
   1/******************************************************************************
   2*******************************************************************************
   3**
   4**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
   5**  Copyright (C) 2004-2009 Red Hat, Inc.  All rights reserved.
   6**
   7**  This copyrighted material is made available to anyone wishing to use,
   8**  modify, copy, or redistribute it subject to the terms and conditions
   9**  of the GNU General Public License v.2.
  10**
  11*******************************************************************************
  12******************************************************************************/
  13
  14/*
  15 * lowcomms.c
  16 *
  17 * This is the "low-level" comms layer.
  18 *
  19 * It is responsible for sending/receiving messages
  20 * from other nodes in the cluster.
  21 *
  22 * Cluster nodes are referred to by their nodeids. nodeids are
  23 * simply 32 bit numbers to the locking module - if they need to
  24 * be expanded for the cluster infrastructure then that is its
  25 * responsibility. It is this layer's
  26 * responsibility to resolve these into IP address or
  27 * whatever it needs for inter-node communication.
  28 *
  29 * The comms level is two kernel threads that deal mainly with
  30 * the receiving of messages from other nodes and passing them
  31 * up to the mid-level comms layer (which understands the
  32 * message format) for execution by the locking core, and
  33 * a send thread which does all the setting up of connections
  34 * to remote nodes and the sending of data. Threads are not allowed
  35 * to send their own data because it may cause them to wait in times
  36 * of high load. Also, this way, the sending thread can collect together
  37 * messages bound for one node and send them in one block.
  38 *
  39 * lowcomms will choose to use either TCP or SCTP as its transport layer
  40 * depending on the configuration variable 'protocol'. This should be set
  41 * to 0 (default) for TCP or 1 for SCTP. It should be configured using a
  42 * cluster-wide mechanism as it must be the same on all nodes of the cluster
  43 * for the DLM to function.
  44 *
  45 */
  46
  47#include <asm/ioctls.h>
  48#include <net/sock.h>
  49#include <net/tcp.h>
  50#include <linux/pagemap.h>
  51#include <linux/file.h>
  52#include <linux/mutex.h>
  53#include <linux/sctp.h>
  54#include <linux/slab.h>
  55#include <net/sctp/sctp.h>
  56#include <net/sctp/user.h>
  57#include <net/ipv6.h>
  58
  59#include "dlm_internal.h"
  60#include "lowcomms.h"
  61#include "midcomms.h"
  62#include "config.h"
  63
  64#define NEEDED_RMEM (4*1024*1024)
  65#define CONN_HASH_SIZE 32
  66
  67/* Number of messages to send before rescheduling */
  68#define MAX_SEND_MSG_COUNT 25
  69
  70struct cbuf {
  71        unsigned int base;
  72        unsigned int len;
  73        unsigned int mask;
  74};
  75
  76static void cbuf_add(struct cbuf *cb, int n)
  77{
  78        cb->len += n;
  79}
  80
  81static int cbuf_data(struct cbuf *cb)
  82{
  83        return ((cb->base + cb->len) & cb->mask);
  84}
  85
  86static void cbuf_init(struct cbuf *cb, int size)
  87{
  88        cb->base = cb->len = 0;
  89        cb->mask = size-1;
  90}
  91
  92static void cbuf_eat(struct cbuf *cb, int n)
  93{
  94        cb->len  -= n;
  95        cb->base += n;
  96        cb->base &= cb->mask;
  97}
  98
  99static bool cbuf_empty(struct cbuf *cb)
 100{
 101        return cb->len == 0;
 102}
 103
 104struct connection {
 105        struct socket *sock;    /* NULL if not connected */
 106        uint32_t nodeid;        /* So we know who we are in the list */
 107        struct mutex sock_mutex;
 108        unsigned long flags;
 109#define CF_READ_PENDING 1
 110#define CF_WRITE_PENDING 2
 111#define CF_CONNECT_PENDING 3
 112#define CF_INIT_PENDING 4
 113#define CF_IS_OTHERCON 5
 114#define CF_CLOSE 6
 115#define CF_APP_LIMITED 7
 116        struct list_head writequeue;  /* List of outgoing writequeue_entries */
 117        spinlock_t writequeue_lock;
 118        int (*rx_action) (struct connection *); /* What to do when active */
 119        void (*connect_action) (struct connection *);   /* What to do to connect */
 120        struct page *rx_page;
 121        struct cbuf cb;
 122        int retries;
 123#define MAX_CONNECT_RETRIES 3
 124        int sctp_assoc;
 125        struct hlist_node list;
 126        struct connection *othercon;
 127        struct work_struct rwork; /* Receive workqueue */
 128        struct work_struct swork; /* Send workqueue */
 129};
 130#define sock2con(x) ((struct connection *)(x)->sk_user_data)
 131
 132/* An entry waiting to be sent */
 133struct writequeue_entry {
 134        struct list_head list;
 135        struct page *page;
 136        int offset;
 137        int len;
 138        int end;
 139        int users;
 140        struct connection *con;
 141};
 142
 143static struct sockaddr_storage *dlm_local_addr[DLM_MAX_ADDR_COUNT];
 144static int dlm_local_count;
 145static int dlm_allow_conn;
 146
 147/* Work queues */
 148static struct workqueue_struct *recv_workqueue;
 149static struct workqueue_struct *send_workqueue;
 150
 151static struct hlist_head connection_hash[CONN_HASH_SIZE];
 152static DEFINE_MUTEX(connections_lock);
 153static struct kmem_cache *con_cache;
 154
 155static void process_recv_sockets(struct work_struct *work);
 156static void process_send_sockets(struct work_struct *work);
 157
 158
 159/* This is deliberately very simple because most clusters have simple
 160   sequential nodeids, so we should be able to go straight to a connection
 161   struct in the array */
 162static inline int nodeid_hash(int nodeid)
 163{
 164        return nodeid & (CONN_HASH_SIZE-1);
 165}
 166
 167static struct connection *__find_con(int nodeid)
 168{
 169        int r;
 170        struct hlist_node *h;
 171        struct connection *con;
 172
 173        r = nodeid_hash(nodeid);
 174
 175        hlist_for_each_entry(con, h, &connection_hash[r], list) {
 176                if (con->nodeid == nodeid)
 177                        return con;
 178        }
 179        return NULL;
 180}
 181
 182/*
 183 * If 'allocation' is zero then we don't attempt to create a new
 184 * connection structure for this node.
 185 */
 186static struct connection *__nodeid2con(int nodeid, gfp_t alloc)
 187{
 188        struct connection *con = NULL;
 189        int r;
 190
 191        con = __find_con(nodeid);
 192        if (con || !alloc)
 193                return con;
 194
 195        con = kmem_cache_zalloc(con_cache, alloc);
 196        if (!con)
 197                return NULL;
 198
 199        r = nodeid_hash(nodeid);
 200        hlist_add_head(&con->list, &connection_hash[r]);
 201
 202        con->nodeid = nodeid;
 203        mutex_init(&con->sock_mutex);
 204        INIT_LIST_HEAD(&con->writequeue);
 205        spin_lock_init(&con->writequeue_lock);
 206        INIT_WORK(&con->swork, process_send_sockets);
 207        INIT_WORK(&con->rwork, process_recv_sockets);
 208
 209        /* Setup action pointers for child sockets */
 210        if (con->nodeid) {
 211                struct connection *zerocon = __find_con(0);
 212
 213                con->connect_action = zerocon->connect_action;
 214                if (!con->rx_action)
 215                        con->rx_action = zerocon->rx_action;
 216        }
 217
 218        return con;
 219}
 220
 221/* Loop round all connections */
 222static void foreach_conn(void (*conn_func)(struct connection *c))
 223{
 224        int i;
 225        struct hlist_node *h, *n;
 226        struct connection *con;
 227
 228        for (i = 0; i < CONN_HASH_SIZE; i++) {
 229                hlist_for_each_entry_safe(con, h, n, &connection_hash[i], list){
 230                        conn_func(con);
 231                }
 232        }
 233}
 234
 235static struct connection *nodeid2con(int nodeid, gfp_t allocation)
 236{
 237        struct connection *con;
 238
 239        mutex_lock(&connections_lock);
 240        con = __nodeid2con(nodeid, allocation);
 241        mutex_unlock(&connections_lock);
 242
 243        return con;
 244}
 245
 246/* This is a bit drastic, but only called when things go wrong */
 247static struct connection *assoc2con(int assoc_id)
 248{
 249        int i;
 250        struct hlist_node *h;
 251        struct connection *con;
 252
 253        mutex_lock(&connections_lock);
 254
 255        for (i = 0 ; i < CONN_HASH_SIZE; i++) {
 256                hlist_for_each_entry(con, h, &connection_hash[i], list) {
 257                        if (con->sctp_assoc == assoc_id) {
 258                                mutex_unlock(&connections_lock);
 259                                return con;
 260                        }
 261                }
 262        }
 263        mutex_unlock(&connections_lock);
 264        return NULL;
 265}
 266
 267static int nodeid_to_addr(int nodeid, struct sockaddr *retaddr)
 268{
 269        struct sockaddr_storage addr;
 270        int error;
 271
 272        if (!dlm_local_count)
 273                return -1;
 274
 275        error = dlm_nodeid_to_addr(nodeid, &addr);
 276        if (error)
 277                return error;
 278
 279        if (dlm_local_addr[0]->ss_family == AF_INET) {
 280                struct sockaddr_in *in4  = (struct sockaddr_in *) &addr;
 281                struct sockaddr_in *ret4 = (struct sockaddr_in *) retaddr;
 282                ret4->sin_addr.s_addr = in4->sin_addr.s_addr;
 283        } else {
 284                struct sockaddr_in6 *in6  = (struct sockaddr_in6 *) &addr;
 285                struct sockaddr_in6 *ret6 = (struct sockaddr_in6 *) retaddr;
 286                ret6->sin6_addr = in6->sin6_addr;
 287        }
 288
 289        return 0;
 290}
 291
 292/* Data available on socket or listen socket received a connect */
 293static void lowcomms_data_ready(struct sock *sk, int count_unused)
 294{
 295        struct connection *con = sock2con(sk);
 296        if (con && !test_and_set_bit(CF_READ_PENDING, &con->flags))
 297                queue_work(recv_workqueue, &con->rwork);
 298}
 299
 300static void lowcomms_write_space(struct sock *sk)
 301{
 302        struct connection *con = sock2con(sk);
 303
 304        if (!con)
 305                return;
 306
 307        clear_bit(SOCK_NOSPACE, &con->sock->flags);
 308
 309        if (test_and_clear_bit(CF_APP_LIMITED, &con->flags)) {
 310                con->sock->sk->sk_write_pending--;
 311                clear_bit(SOCK_ASYNC_NOSPACE, &con->sock->flags);
 312        }
 313
 314        if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags))
 315                queue_work(send_workqueue, &con->swork);
 316}
 317
 318static inline void lowcomms_connect_sock(struct connection *con)
 319{
 320        if (test_bit(CF_CLOSE, &con->flags))
 321                return;
 322        if (!test_and_set_bit(CF_CONNECT_PENDING, &con->flags))
 323                queue_work(send_workqueue, &con->swork);
 324}
 325
 326static void lowcomms_state_change(struct sock *sk)
 327{
 328        if (sk->sk_state == TCP_ESTABLISHED)
 329                lowcomms_write_space(sk);
 330}
 331
 332int dlm_lowcomms_connect_node(int nodeid)
 333{
 334        struct connection *con;
 335
 336        /* with sctp there's no connecting without sending */
 337        if (dlm_config.ci_protocol != 0)
 338                return 0;
 339
 340        if (nodeid == dlm_our_nodeid())
 341                return 0;
 342
 343        con = nodeid2con(nodeid, GFP_NOFS);
 344        if (!con)
 345                return -ENOMEM;
 346        lowcomms_connect_sock(con);
 347        return 0;
 348}
 349
 350/* Make a socket active */
 351static int add_sock(struct socket *sock, struct connection *con)
 352{
 353        con->sock = sock;
 354
 355        /* Install a data_ready callback */
 356        con->sock->sk->sk_data_ready = lowcomms_data_ready;
 357        con->sock->sk->sk_write_space = lowcomms_write_space;
 358        con->sock->sk->sk_state_change = lowcomms_state_change;
 359        con->sock->sk->sk_user_data = con;
 360        con->sock->sk->sk_allocation = GFP_NOFS;
 361        return 0;
 362}
 363
 364/* Add the port number to an IPv6 or 4 sockaddr and return the address
 365   length */
 366static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port,
 367                          int *addr_len)
 368{
 369        saddr->ss_family =  dlm_local_addr[0]->ss_family;
 370        if (saddr->ss_family == AF_INET) {
 371                struct sockaddr_in *in4_addr = (struct sockaddr_in *)saddr;
 372                in4_addr->sin_port = cpu_to_be16(port);
 373                *addr_len = sizeof(struct sockaddr_in);
 374                memset(&in4_addr->sin_zero, 0, sizeof(in4_addr->sin_zero));
 375        } else {
 376                struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)saddr;
 377                in6_addr->sin6_port = cpu_to_be16(port);
 378                *addr_len = sizeof(struct sockaddr_in6);
 379        }
 380        memset((char *)saddr + *addr_len, 0, sizeof(struct sockaddr_storage) - *addr_len);
 381}
 382
 383/* Close a remote connection and tidy up */
 384static void close_connection(struct connection *con, bool and_other)
 385{
 386        mutex_lock(&con->sock_mutex);
 387
 388        if (con->sock) {
 389                sock_release(con->sock);
 390                con->sock = NULL;
 391        }
 392        if (con->othercon && and_other) {
 393                /* Will only re-enter once. */
 394                close_connection(con->othercon, false);
 395        }
 396        if (con->rx_page) {
 397                __free_page(con->rx_page);
 398                con->rx_page = NULL;
 399        }
 400
 401        con->retries = 0;
 402        mutex_unlock(&con->sock_mutex);
 403}
 404
 405/* We only send shutdown messages to nodes that are not part of the cluster */
 406static void sctp_send_shutdown(sctp_assoc_t associd)
 407{
 408        static char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
 409        struct msghdr outmessage;
 410        struct cmsghdr *cmsg;
 411        struct sctp_sndrcvinfo *sinfo;
 412        int ret;
 413        struct connection *con;
 414
 415        con = nodeid2con(0,0);
 416        BUG_ON(con == NULL);
 417
 418        outmessage.msg_name = NULL;
 419        outmessage.msg_namelen = 0;
 420        outmessage.msg_control = outcmsg;
 421        outmessage.msg_controllen = sizeof(outcmsg);
 422        outmessage.msg_flags = MSG_EOR;
 423
 424        cmsg = CMSG_FIRSTHDR(&outmessage);
 425        cmsg->cmsg_level = IPPROTO_SCTP;
 426        cmsg->cmsg_type = SCTP_SNDRCV;
 427        cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
 428        outmessage.msg_controllen = cmsg->cmsg_len;
 429        sinfo = CMSG_DATA(cmsg);
 430        memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo));
 431
 432        sinfo->sinfo_flags |= MSG_EOF;
 433        sinfo->sinfo_assoc_id = associd;
 434
 435        ret = kernel_sendmsg(con->sock, &outmessage, NULL, 0, 0);
 436
 437        if (ret != 0)
 438                log_print("send EOF to node failed: %d", ret);
 439}
 440
 441static void sctp_init_failed_foreach(struct connection *con)
 442{
 443        con->sctp_assoc = 0;
 444        if (test_and_clear_bit(CF_CONNECT_PENDING, &con->flags)) {
 445                if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags))
 446                        queue_work(send_workqueue, &con->swork);
 447        }
 448}
 449
 450/* INIT failed but we don't know which node...
 451   restart INIT on all pending nodes */
 452static void sctp_init_failed(void)
 453{
 454        mutex_lock(&connections_lock);
 455
 456        foreach_conn(sctp_init_failed_foreach);
 457
 458        mutex_unlock(&connections_lock);
 459}
 460
 461/* Something happened to an association */
 462static void process_sctp_notification(struct connection *con,
 463                                      struct msghdr *msg, char *buf)
 464{
 465        union sctp_notification *sn = (union sctp_notification *)buf;
 466
 467        if (sn->sn_header.sn_type == SCTP_ASSOC_CHANGE) {
 468                switch (sn->sn_assoc_change.sac_state) {
 469
 470                case SCTP_COMM_UP:
 471                case SCTP_RESTART:
 472                {
 473                        /* Check that the new node is in the lockspace */
 474                        struct sctp_prim prim;
 475                        int nodeid;
 476                        int prim_len, ret;
 477                        int addr_len;
 478                        struct connection *new_con;
 479
 480                        /*
 481                         * We get this before any data for an association.
 482                         * We verify that the node is in the cluster and
 483                         * then peel off a socket for it.
 484                         */
 485                        if ((int)sn->sn_assoc_change.sac_assoc_id <= 0) {
 486                                log_print("COMM_UP for invalid assoc ID %d",
 487                                         (int)sn->sn_assoc_change.sac_assoc_id);
 488                                sctp_init_failed();
 489                                return;
 490                        }
 491                        memset(&prim, 0, sizeof(struct sctp_prim));
 492                        prim_len = sizeof(struct sctp_prim);
 493                        prim.ssp_assoc_id = sn->sn_assoc_change.sac_assoc_id;
 494
 495                        ret = kernel_getsockopt(con->sock,
 496                                                IPPROTO_SCTP,
 497                                                SCTP_PRIMARY_ADDR,
 498                                                (char*)&prim,
 499                                                &prim_len);
 500                        if (ret < 0) {
 501                                log_print("getsockopt/sctp_primary_addr on "
 502                                          "new assoc %d failed : %d",
 503                                          (int)sn->sn_assoc_change.sac_assoc_id,
 504                                          ret);
 505
 506                                /* Retry INIT later */
 507                                new_con = assoc2con(sn->sn_assoc_change.sac_assoc_id);
 508                                if (new_con)
 509                                        clear_bit(CF_CONNECT_PENDING, &con->flags);
 510                                return;
 511                        }
 512                        make_sockaddr(&prim.ssp_addr, 0, &addr_len);
 513                        if (dlm_addr_to_nodeid(&prim.ssp_addr, &nodeid)) {
 514                                unsigned char *b=(unsigned char *)&prim.ssp_addr;
 515                                log_print("reject connect from unknown addr");
 516                                print_hex_dump_bytes("ss: ", DUMP_PREFIX_NONE, 
 517                                                     b, sizeof(struct sockaddr_storage));
 518                                sctp_send_shutdown(prim.ssp_assoc_id);
 519                                return;
 520                        }
 521
 522                        new_con = nodeid2con(nodeid, GFP_NOFS);
 523                        if (!new_con)
 524                                return;
 525
 526                        /* Peel off a new sock */
 527                        sctp_lock_sock(con->sock->sk);
 528                        ret = sctp_do_peeloff(con->sock->sk,
 529                                sn->sn_assoc_change.sac_assoc_id,
 530                                &new_con->sock);
 531                        sctp_release_sock(con->sock->sk);
 532                        if (ret < 0) {
 533                                log_print("Can't peel off a socket for "
 534                                          "connection %d to node %d: err=%d",
 535                                          (int)sn->sn_assoc_change.sac_assoc_id,
 536                                          nodeid, ret);
 537                                return;
 538                        }
 539                        add_sock(new_con->sock, new_con);
 540
 541                        log_print("connecting to %d sctp association %d",
 542                                 nodeid, (int)sn->sn_assoc_change.sac_assoc_id);
 543
 544                        /* Send any pending writes */
 545                        clear_bit(CF_CONNECT_PENDING, &new_con->flags);
 546                        clear_bit(CF_INIT_PENDING, &con->flags);
 547                        if (!test_and_set_bit(CF_WRITE_PENDING, &new_con->flags)) {
 548                                queue_work(send_workqueue, &new_con->swork);
 549                        }
 550                        if (!test_and_set_bit(CF_READ_PENDING, &new_con->flags))
 551                                queue_work(recv_workqueue, &new_con->rwork);
 552                }
 553                break;
 554
 555                case SCTP_COMM_LOST:
 556                case SCTP_SHUTDOWN_COMP:
 557                {
 558                        con = assoc2con(sn->sn_assoc_change.sac_assoc_id);
 559                        if (con) {
 560                                con->sctp_assoc = 0;
 561                        }
 562                }
 563                break;
 564
 565                /* We don't know which INIT failed, so clear the PENDING flags
 566                 * on them all.  if assoc_id is zero then it will then try
 567                 * again */
 568
 569                case SCTP_CANT_STR_ASSOC:
 570                {
 571                        log_print("Can't start SCTP association - retrying");
 572                        sctp_init_failed();
 573                }
 574                break;
 575
 576                default:
 577                        log_print("unexpected SCTP assoc change id=%d state=%d",
 578                                  (int)sn->sn_assoc_change.sac_assoc_id,
 579                                  sn->sn_assoc_change.sac_state);
 580                }
 581        }
 582}
 583
 584/* Data received from remote end */
 585static int receive_from_sock(struct connection *con)
 586{
 587        int ret = 0;
 588        struct msghdr msg = {};
 589        struct kvec iov[2];
 590        unsigned len;
 591        int r;
 592        int call_again_soon = 0;
 593        int nvec;
 594        char incmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
 595
 596        mutex_lock(&con->sock_mutex);
 597
 598        if (con->sock == NULL) {
 599                ret = -EAGAIN;
 600                goto out_close;
 601        }
 602
 603        if (con->rx_page == NULL) {
 604                /*
 605                 * This doesn't need to be atomic, but I think it should
 606                 * improve performance if it is.
 607                 */
 608                con->rx_page = alloc_page(GFP_ATOMIC);
 609                if (con->rx_page == NULL)
 610                        goto out_resched;
 611                cbuf_init(&con->cb, PAGE_CACHE_SIZE);
 612        }
 613
 614        /* Only SCTP needs these really */
 615        memset(&incmsg, 0, sizeof(incmsg));
 616        msg.msg_control = incmsg;
 617        msg.msg_controllen = sizeof(incmsg);
 618
 619        /*
 620         * iov[0] is the bit of the circular buffer between the current end
 621         * point (cb.base + cb.len) and the end of the buffer.
 622         */
 623        iov[0].iov_len = con->cb.base - cbuf_data(&con->cb);
 624        iov[0].iov_base = page_address(con->rx_page) + cbuf_data(&con->cb);
 625        iov[1].iov_len = 0;
 626        nvec = 1;
 627
 628        /*
 629         * iov[1] is the bit of the circular buffer between the start of the
 630         * buffer and the start of the currently used section (cb.base)
 631         */
 632        if (cbuf_data(&con->cb) >= con->cb.base) {
 633                iov[0].iov_len = PAGE_CACHE_SIZE - cbuf_data(&con->cb);
 634                iov[1].iov_len = con->cb.base;
 635                iov[1].iov_base = page_address(con->rx_page);
 636                nvec = 2;
 637        }
 638        len = iov[0].iov_len + iov[1].iov_len;
 639
 640        r = ret = kernel_recvmsg(con->sock, &msg, iov, nvec, len,
 641                               MSG_DONTWAIT | MSG_NOSIGNAL);
 642        if (ret <= 0)
 643                goto out_close;
 644
 645        /* Process SCTP notifications */
 646        if (msg.msg_flags & MSG_NOTIFICATION) {
 647                msg.msg_control = incmsg;
 648                msg.msg_controllen = sizeof(incmsg);
 649
 650                process_sctp_notification(con, &msg,
 651                                page_address(con->rx_page) + con->cb.base);
 652                mutex_unlock(&con->sock_mutex);
 653                return 0;
 654        }
 655        BUG_ON(con->nodeid == 0);
 656
 657        if (ret == len)
 658                call_again_soon = 1;
 659        cbuf_add(&con->cb, ret);
 660        ret = dlm_process_incoming_buffer(con->nodeid,
 661                                          page_address(con->rx_page),
 662                                          con->cb.base, con->cb.len,
 663                                          PAGE_CACHE_SIZE);
 664        if (ret == -EBADMSG) {
 665                log_print("lowcomms: addr=%p, base=%u, len=%u, "
 666                          "iov_len=%u, iov_base[0]=%p, read=%d",
 667                          page_address(con->rx_page), con->cb.base, con->cb.len,
 668                          len, iov[0].iov_base, r);
 669        }
 670        if (ret < 0)
 671                goto out_close;
 672        cbuf_eat(&con->cb, ret);
 673
 674        if (cbuf_empty(&con->cb) && !call_again_soon) {
 675                __free_page(con->rx_page);
 676                con->rx_page = NULL;
 677        }
 678
 679        if (call_again_soon)
 680                goto out_resched;
 681        mutex_unlock(&con->sock_mutex);
 682        return 0;
 683
 684out_resched:
 685        if (!test_and_set_bit(CF_READ_PENDING, &con->flags))
 686                queue_work(recv_workqueue, &con->rwork);
 687        mutex_unlock(&con->sock_mutex);
 688        return -EAGAIN;
 689
 690out_close:
 691        mutex_unlock(&con->sock_mutex);
 692        if (ret != -EAGAIN) {
 693                close_connection(con, false);
 694                /* Reconnect when there is something to send */
 695        }
 696        /* Don't return success if we really got EOF */
 697        if (ret == 0)
 698                ret = -EAGAIN;
 699
 700        return ret;
 701}
 702
 703/* Listening socket is busy, accept a connection */
 704static int tcp_accept_from_sock(struct connection *con)
 705{
 706        int result;
 707        struct sockaddr_storage peeraddr;
 708        struct socket *newsock;
 709        int len;
 710        int nodeid;
 711        struct connection *newcon;
 712        struct connection *addcon;
 713
 714        mutex_lock(&connections_lock);
 715        if (!dlm_allow_conn) {
 716                mutex_unlock(&connections_lock);
 717                return -1;
 718        }
 719        mutex_unlock(&connections_lock);
 720
 721        memset(&peeraddr, 0, sizeof(peeraddr));
 722        result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM,
 723                                  IPPROTO_TCP, &newsock);
 724        if (result < 0)
 725                return -ENOMEM;
 726
 727        mutex_lock_nested(&con->sock_mutex, 0);
 728
 729        result = -ENOTCONN;
 730        if (con->sock == NULL)
 731                goto accept_err;
 732
 733        newsock->type = con->sock->type;
 734        newsock->ops = con->sock->ops;
 735
 736        result = con->sock->ops->accept(con->sock, newsock, O_NONBLOCK);
 737        if (result < 0)
 738                goto accept_err;
 739
 740        /* Get the connected socket's peer */
 741        memset(&peeraddr, 0, sizeof(peeraddr));
 742        if (newsock->ops->getname(newsock, (struct sockaddr *)&peeraddr,
 743                                  &len, 2)) {
 744                result = -ECONNABORTED;
 745                goto accept_err;
 746        }
 747
 748        /* Get the new node's NODEID */
 749        make_sockaddr(&peeraddr, 0, &len);
 750        if (dlm_addr_to_nodeid(&peeraddr, &nodeid)) {
 751                unsigned char *b=(unsigned char *)&peeraddr;
 752                log_print("connect from non cluster node");
 753                print_hex_dump_bytes("ss: ", DUMP_PREFIX_NONE, 
 754                                     b, sizeof(struct sockaddr_storage));
 755                sock_release(newsock);
 756                mutex_unlock(&con->sock_mutex);
 757                return -1;
 758        }
 759
 760        log_print("got connection from %d", nodeid);
 761
 762        /*  Check to see if we already have a connection to this node. This
 763         *  could happen if the two nodes initiate a connection at roughly
 764         *  the same time and the connections cross on the wire.
 765         *  In this case we store the incoming one in "othercon"
 766         */
 767        newcon = nodeid2con(nodeid, GFP_NOFS);
 768        if (!newcon) {
 769                result = -ENOMEM;
 770                goto accept_err;
 771        }
 772        mutex_lock_nested(&newcon->sock_mutex, 1);
 773        if (newcon->sock) {
 774                struct connection *othercon = newcon->othercon;
 775
 776                if (!othercon) {
 777                        othercon = kmem_cache_zalloc(con_cache, GFP_NOFS);
 778                        if (!othercon) {
 779                                log_print("failed to allocate incoming socket");
 780                                mutex_unlock(&newcon->sock_mutex);
 781                                result = -ENOMEM;
 782                                goto accept_err;
 783                        }
 784                        othercon->nodeid = nodeid;
 785                        othercon->rx_action = receive_from_sock;
 786                        mutex_init(&othercon->sock_mutex);
 787                        INIT_WORK(&othercon->swork, process_send_sockets);
 788                        INIT_WORK(&othercon->rwork, process_recv_sockets);
 789                        set_bit(CF_IS_OTHERCON, &othercon->flags);
 790                }
 791                if (!othercon->sock) {
 792                        newcon->othercon = othercon;
 793                        othercon->sock = newsock;
 794                        newsock->sk->sk_user_data = othercon;
 795                        add_sock(newsock, othercon);
 796                        addcon = othercon;
 797                }
 798                else {
 799                        printk("Extra connection from node %d attempted\n", nodeid);
 800                        result = -EAGAIN;
 801                        mutex_unlock(&newcon->sock_mutex);
 802                        goto accept_err;
 803                }
 804        }
 805        else {
 806                newsock->sk->sk_user_data = newcon;
 807                newcon->rx_action = receive_from_sock;
 808                add_sock(newsock, newcon);
 809                addcon = newcon;
 810        }
 811
 812        mutex_unlock(&newcon->sock_mutex);
 813
 814        /*
 815         * Add it to the active queue in case we got data
 816         * between processing the accept adding the socket
 817         * to the read_sockets list
 818         */
 819        if (!test_and_set_bit(CF_READ_PENDING, &addcon->flags))
 820                queue_work(recv_workqueue, &addcon->rwork);
 821        mutex_unlock(&con->sock_mutex);
 822
 823        return 0;
 824
 825accept_err:
 826        mutex_unlock(&con->sock_mutex);
 827        sock_release(newsock);
 828
 829        if (result != -EAGAIN)
 830                log_print("error accepting connection from node: %d", result);
 831        return result;
 832}
 833
 834static void free_entry(struct writequeue_entry *e)
 835{
 836        __free_page(e->page);
 837        kfree(e);
 838}
 839
 840/* Initiate an SCTP association.
 841   This is a special case of send_to_sock() in that we don't yet have a
 842   peeled-off socket for this association, so we use the listening socket
 843   and add the primary IP address of the remote node.
 844 */
 845static void sctp_init_assoc(struct connection *con)
 846{
 847        struct sockaddr_storage rem_addr;
 848        char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
 849        struct msghdr outmessage;
 850        struct cmsghdr *cmsg;
 851        struct sctp_sndrcvinfo *sinfo;
 852        struct connection *base_con;
 853        struct writequeue_entry *e;
 854        int len, offset;
 855        int ret;
 856        int addrlen;
 857        struct kvec iov[1];
 858
 859        if (test_and_set_bit(CF_INIT_PENDING, &con->flags))
 860                return;
 861
 862        if (con->retries++ > MAX_CONNECT_RETRIES)
 863                return;
 864
 865        if (nodeid_to_addr(con->nodeid, (struct sockaddr *)&rem_addr)) {
 866                log_print("no address for nodeid %d", con->nodeid);
 867                return;
 868        }
 869        base_con = nodeid2con(0, 0);
 870        BUG_ON(base_con == NULL);
 871
 872        make_sockaddr(&rem_addr, dlm_config.ci_tcp_port, &addrlen);
 873
 874        outmessage.msg_name = &rem_addr;
 875        outmessage.msg_namelen = addrlen;
 876        outmessage.msg_control = outcmsg;
 877        outmessage.msg_controllen = sizeof(outcmsg);
 878        outmessage.msg_flags = MSG_EOR;
 879
 880        spin_lock(&con->writequeue_lock);
 881
 882        if (list_empty(&con->writequeue)) {
 883                spin_unlock(&con->writequeue_lock);
 884                log_print("writequeue empty for nodeid %d", con->nodeid);
 885                return;
 886        }
 887
 888        e = list_first_entry(&con->writequeue, struct writequeue_entry, list);
 889        len = e->len;
 890        offset = e->offset;
 891        spin_unlock(&con->writequeue_lock);
 892
 893        /* Send the first block off the write queue */
 894        iov[0].iov_base = page_address(e->page)+offset;
 895        iov[0].iov_len = len;
 896
 897        cmsg = CMSG_FIRSTHDR(&outmessage);
 898        cmsg->cmsg_level = IPPROTO_SCTP;
 899        cmsg->cmsg_type = SCTP_SNDRCV;
 900        cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
 901        sinfo = CMSG_DATA(cmsg);
 902        memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo));
 903        sinfo->sinfo_ppid = cpu_to_le32(dlm_our_nodeid());
 904        outmessage.msg_controllen = cmsg->cmsg_len;
 905
 906        ret = kernel_sendmsg(base_con->sock, &outmessage, iov, 1, len);
 907        if (ret < 0) {
 908                log_print("Send first packet to node %d failed: %d",
 909                          con->nodeid, ret);
 910
 911                /* Try again later */
 912                clear_bit(CF_CONNECT_PENDING, &con->flags);
 913                clear_bit(CF_INIT_PENDING, &con->flags);
 914        }
 915        else {
 916                spin_lock(&con->writequeue_lock);
 917                e->offset += ret;
 918                e->len -= ret;
 919
 920                if (e->len == 0 && e->users == 0) {
 921                        list_del(&e->list);
 922                        free_entry(e);
 923                }
 924                spin_unlock(&con->writequeue_lock);
 925        }
 926}
 927
 928/* Connect a new socket to its peer */
 929static void tcp_connect_to_sock(struct connection *con)
 930{
 931        int result = -EHOSTUNREACH;
 932        struct sockaddr_storage saddr, src_addr;
 933        int addr_len;
 934        struct socket *sock = NULL;
 935        int one = 1;
 936
 937        if (con->nodeid == 0) {
 938                log_print("attempt to connect sock 0 foiled");
 939                return;
 940        }
 941
 942        mutex_lock(&con->sock_mutex);
 943        if (con->retries++ > MAX_CONNECT_RETRIES)
 944                goto out;
 945
 946        /* Some odd races can cause double-connects, ignore them */
 947        if (con->sock) {
 948                result = 0;
 949                goto out;
 950        }
 951
 952        /* Create a socket to communicate with */
 953        result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM,
 954                                  IPPROTO_TCP, &sock);
 955        if (result < 0)
 956                goto out_err;
 957
 958        memset(&saddr, 0, sizeof(saddr));
 959        if (dlm_nodeid_to_addr(con->nodeid, &saddr))
 960                goto out_err;
 961
 962        sock->sk->sk_user_data = con;
 963        con->rx_action = receive_from_sock;
 964        con->connect_action = tcp_connect_to_sock;
 965        add_sock(sock, con);
 966
 967        /* Bind to our cluster-known address connecting to avoid
 968           routing problems */
 969        memcpy(&src_addr, dlm_local_addr[0], sizeof(src_addr));
 970        make_sockaddr(&src_addr, 0, &addr_len);
 971        result = sock->ops->bind(sock, (struct sockaddr *) &src_addr,
 972                                 addr_len);
 973        if (result < 0) {
 974                log_print("could not bind for connect: %d", result);
 975                /* This *may* not indicate a critical error */
 976        }
 977
 978        make_sockaddr(&saddr, dlm_config.ci_tcp_port, &addr_len);
 979
 980        log_print("connecting to %d", con->nodeid);
 981
 982        /* Turn off Nagle's algorithm */
 983        kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY, (char *)&one,
 984                          sizeof(one));
 985
 986        result =
 987                sock->ops->connect(sock, (struct sockaddr *)&saddr, addr_len,
 988                                   O_NONBLOCK);
 989        if (result == -EINPROGRESS)
 990                result = 0;
 991        if (result == 0)
 992                goto out;
 993
 994out_err:
 995        if (con->sock) {
 996                sock_release(con->sock);
 997                con->sock = NULL;
 998        } else if (sock) {
 999                sock_release(sock);
1000        }
1001        /*
1002         * Some errors are fatal and this list might need adjusting. For other
1003         * errors we try again until the max number of retries is reached.
1004         */
1005        if (result != -EHOSTUNREACH && result != -ENETUNREACH &&
1006            result != -ENETDOWN && result != -EINVAL
1007            && result != -EPROTONOSUPPORT) {
1008                lowcomms_connect_sock(con);
1009                result = 0;
1010        }
1011out:
1012        mutex_unlock(&con->sock_mutex);
1013        return;
1014}
1015
1016static struct socket *tcp_create_listen_sock(struct connection *con,
1017                                             struct sockaddr_storage *saddr)
1018{
1019        struct socket *sock = NULL;
1020        int result = 0;
1021        int one = 1;
1022        int addr_len;
1023
1024        if (dlm_local_addr[0]->ss_family == AF_INET)
1025                addr_len = sizeof(struct sockaddr_in);
1026        else
1027                addr_len = sizeof(struct sockaddr_in6);
1028
1029        /* Create a socket to communicate with */
1030        result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM,
1031                                  IPPROTO_TCP, &sock);
1032        if (result < 0) {
1033                log_print("Can't create listening comms socket");
1034                goto create_out;
1035        }
1036
1037        /* Turn off Nagle's algorithm */
1038        kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY, (char *)&one,
1039                          sizeof(one));
1040
1041        result = kernel_setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,
1042                                   (char *)&one, sizeof(one));
1043
1044        if (result < 0) {
1045                log_print("Failed to set SO_REUSEADDR on socket: %d", result);
1046        }
1047        sock->sk->sk_user_data = con;
1048        con->rx_action = tcp_accept_from_sock;
1049        con->connect_action = tcp_connect_to_sock;
1050        con->sock = sock;
1051
1052        /* Bind to our port */
1053        make_sockaddr(saddr, dlm_config.ci_tcp_port, &addr_len);
1054        result = sock->ops->bind(sock, (struct sockaddr *) saddr, addr_len);
1055        if (result < 0) {
1056                log_print("Can't bind to port %d", dlm_config.ci_tcp_port);
1057                sock_release(sock);
1058                sock = NULL;
1059                con->sock = NULL;
1060                goto create_out;
1061        }
1062        result = kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
1063                                 (char *)&one, sizeof(one));
1064        if (result < 0) {
1065                log_print("Set keepalive failed: %d", result);
1066        }
1067
1068        result = sock->ops->listen(sock, 5);
1069        if (result < 0) {
1070                log_print("Can't listen on port %d", dlm_config.ci_tcp_port);
1071                sock_release(sock);
1072                sock = NULL;
1073                goto create_out;
1074        }
1075
1076create_out:
1077        return sock;
1078}
1079
1080/* Get local addresses */
1081static void init_local(void)
1082{
1083        struct sockaddr_storage sas, *addr;
1084        int i;
1085
1086        dlm_local_count = 0;
1087        for (i = 0; i < DLM_MAX_ADDR_COUNT; i++) {
1088                if (dlm_our_addr(&sas, i))
1089                        break;
1090
1091                addr = kmalloc(sizeof(*addr), GFP_NOFS);
1092                if (!addr)
1093                        break;
1094                memcpy(addr, &sas, sizeof(*addr));
1095                dlm_local_addr[dlm_local_count++] = addr;
1096        }
1097}
1098
1099/* Bind to an IP address. SCTP allows multiple address so it can do
1100   multi-homing */
1101static int add_sctp_bind_addr(struct connection *sctp_con,
1102                              struct sockaddr_storage *addr,
1103                              int addr_len, int num)
1104{
1105        int result = 0;
1106
1107        if (num == 1)
1108                result = kernel_bind(sctp_con->sock,
1109                                     (struct sockaddr *) addr,
1110                                     addr_len);
1111        else
1112                result = kernel_setsockopt(sctp_con->sock, SOL_SCTP,
1113                                           SCTP_SOCKOPT_BINDX_ADD,
1114                                           (char *)addr, addr_len);
1115
1116        if (result < 0)
1117                log_print("Can't bind to port %d addr number %d",
1118                          dlm_config.ci_tcp_port, num);
1119
1120        return result;
1121}
1122
1123/* Initialise SCTP socket and bind to all interfaces */
1124static int sctp_listen_for_all(void)
1125{
1126        struct socket *sock = NULL;
1127        struct sockaddr_storage localaddr;
1128        struct sctp_event_subscribe subscribe;
1129        int result = -EINVAL, num = 1, i, addr_len;
1130        struct connection *con = nodeid2con(0, GFP_NOFS);
1131        int bufsize = NEEDED_RMEM;
1132
1133        if (!con)
1134                return -ENOMEM;
1135
1136        log_print("Using SCTP for communications");
1137
1138        result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_SEQPACKET,
1139                                  IPPROTO_SCTP, &sock);
1140        if (result < 0) {
1141                log_print("Can't create comms socket, check SCTP is loaded");
1142                goto out;
1143        }
1144
1145        /* Listen for events */
1146        memset(&subscribe, 0, sizeof(subscribe));
1147        subscribe.sctp_data_io_event = 1;
1148        subscribe.sctp_association_event = 1;
1149        subscribe.sctp_send_failure_event = 1;
1150        subscribe.sctp_shutdown_event = 1;
1151        subscribe.sctp_partial_delivery_event = 1;
1152
1153        result = kernel_setsockopt(sock, SOL_SOCKET, SO_RCVBUFFORCE,
1154                                 (char *)&bufsize, sizeof(bufsize));
1155        if (result)
1156                log_print("Error increasing buffer space on socket %d", result);
1157
1158        result = kernel_setsockopt(sock, SOL_SCTP, SCTP_EVENTS,
1159                                   (char *)&subscribe, sizeof(subscribe));
1160        if (result < 0) {
1161                log_print("Failed to set SCTP_EVENTS on socket: result=%d",
1162                          result);
1163                goto create_delsock;
1164        }
1165
1166        /* Init con struct */
1167        sock->sk->sk_user_data = con;
1168        con->sock = sock;
1169        con->sock->sk->sk_data_ready = lowcomms_data_ready;
1170        con->rx_action = receive_from_sock;
1171        con->connect_action = sctp_init_assoc;
1172
1173        /* Bind to all interfaces. */
1174        for (i = 0; i < dlm_local_count; i++) {
1175                memcpy(&localaddr, dlm_local_addr[i], sizeof(localaddr));
1176                make_sockaddr(&localaddr, dlm_config.ci_tcp_port, &addr_len);
1177
1178                result = add_sctp_bind_addr(con, &localaddr, addr_len, num);
1179                if (result)
1180                        goto create_delsock;
1181                ++num;
1182        }
1183
1184        result = sock->ops->listen(sock, 5);
1185        if (result < 0) {
1186                log_print("Can't set socket listening");
1187                goto create_delsock;
1188        }
1189
1190        return 0;
1191
1192create_delsock:
1193        sock_release(sock);
1194        con->sock = NULL;
1195out:
1196        return result;
1197}
1198
1199static int tcp_listen_for_all(void)
1200{
1201        struct socket *sock = NULL;
1202        struct connection *con = nodeid2con(0, GFP_NOFS);
1203        int result = -EINVAL;
1204
1205        if (!con)
1206                return -ENOMEM;
1207
1208        /* We don't support multi-homed hosts */
1209        if (dlm_local_addr[1] != NULL) {
1210                log_print("TCP protocol can't handle multi-homed hosts, "
1211                          "try SCTP");
1212                return -EINVAL;
1213        }
1214
1215        log_print("Using TCP for communications");
1216
1217        sock = tcp_create_listen_sock(con, dlm_local_addr[0]);
1218        if (sock) {
1219                add_sock(sock, con);
1220                result = 0;
1221        }
1222        else {
1223                result = -EADDRINUSE;
1224        }
1225
1226        return result;
1227}
1228
1229
1230
1231static struct writequeue_entry *new_writequeue_entry(struct connection *con,
1232                                                     gfp_t allocation)
1233{
1234        struct writequeue_entry *entry;
1235
1236        entry = kmalloc(sizeof(struct writequeue_entry), allocation);
1237        if (!entry)
1238                return NULL;
1239
1240        entry->page = alloc_page(allocation);
1241        if (!entry->page) {
1242                kfree(entry);
1243                return NULL;
1244        }
1245
1246        entry->offset = 0;
1247        entry->len = 0;
1248        entry->end = 0;
1249        entry->users = 0;
1250        entry->con = con;
1251
1252        return entry;
1253}
1254
1255void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
1256{
1257        struct connection *con;
1258        struct writequeue_entry *e;
1259        int offset = 0;
1260        int users = 0;
1261
1262        con = nodeid2con(nodeid, allocation);
1263        if (!con)
1264                return NULL;
1265
1266        spin_lock(&con->writequeue_lock);
1267        e = list_entry(con->writequeue.prev, struct writequeue_entry, list);
1268        if ((&e->list == &con->writequeue) ||
1269            (PAGE_CACHE_SIZE - e->end < len)) {
1270                e = NULL;
1271        } else {
1272                offset = e->end;
1273                e->end += len;
1274                users = e->users++;
1275        }
1276        spin_unlock(&con->writequeue_lock);
1277
1278        if (e) {
1279        got_one:
1280                *ppc = page_address(e->page) + offset;
1281                return e;
1282        }
1283
1284        e = new_writequeue_entry(con, allocation);
1285        if (e) {
1286                spin_lock(&con->writequeue_lock);
1287                offset = e->end;
1288                e->end += len;
1289                users = e->users++;
1290                list_add_tail(&e->list, &con->writequeue);
1291                spin_unlock(&con->writequeue_lock);
1292                goto got_one;
1293        }
1294        return NULL;
1295}
1296
1297void dlm_lowcomms_commit_buffer(void *mh)
1298{
1299        struct writequeue_entry *e = (struct writequeue_entry *)mh;
1300        struct connection *con = e->con;
1301        int users;
1302
1303        spin_lock(&con->writequeue_lock);
1304        users = --e->users;
1305        if (users)
1306                goto out;
1307        e->len = e->end - e->offset;
1308        spin_unlock(&con->writequeue_lock);
1309
1310        if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags)) {
1311                queue_work(send_workqueue, &con->swork);
1312        }
1313        return;
1314
1315out:
1316        spin_unlock(&con->writequeue_lock);
1317        return;
1318}
1319
1320/* Send a message */
1321static void send_to_sock(struct connection *con)
1322{
1323        int ret = 0;
1324        const int msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL;
1325        struct writequeue_entry *e;
1326        int len, offset;
1327        int count = 0;
1328
1329        mutex_lock(&con->sock_mutex);
1330        if (con->sock == NULL)
1331                goto out_connect;
1332
1333        spin_lock(&con->writequeue_lock);
1334        for (;;) {
1335                e = list_entry(con->writequeue.next, struct writequeue_entry,
1336                               list);
1337                if ((struct list_head *) e == &con->writequeue)
1338                        break;
1339
1340                len = e->len;
1341                offset = e->offset;
1342                BUG_ON(len == 0 && e->users == 0);
1343                spin_unlock(&con->writequeue_lock);
1344
1345                ret = 0;
1346                if (len) {
1347                        ret = kernel_sendpage(con->sock, e->page, offset, len,
1348                                              msg_flags);
1349                        if (ret == -EAGAIN || ret == 0) {
1350                                if (ret == -EAGAIN &&
1351                                    test_bit(SOCK_ASYNC_NOSPACE, &con->sock->flags) &&
1352                                    !test_and_set_bit(CF_APP_LIMITED, &con->flags)) {
1353                                        /* Notify TCP that we're limited by the
1354                                         * application window size.
1355                                         */
1356                                        set_bit(SOCK_NOSPACE, &con->sock->flags);
1357                                        con->sock->sk->sk_write_pending++;
1358                                }
1359                                cond_resched();
1360                                goto out;
1361                        }
1362                        if (ret <= 0)
1363                                goto send_error;
1364                }
1365
1366                /* Don't starve people filling buffers */
1367                if (++count >= MAX_SEND_MSG_COUNT) {
1368                        cond_resched();
1369                        count = 0;
1370                }
1371
1372                spin_lock(&con->writequeue_lock);
1373                e->offset += ret;
1374                e->len -= ret;
1375
1376                if (e->len == 0 && e->users == 0) {
1377                        list_del(&e->list);
1378                        free_entry(e);
1379                        continue;
1380                }
1381        }
1382        spin_unlock(&con->writequeue_lock);
1383out:
1384        mutex_unlock(&con->sock_mutex);
1385        return;
1386
1387send_error:
1388        mutex_unlock(&con->sock_mutex);
1389        close_connection(con, false);
1390        lowcomms_connect_sock(con);
1391        return;
1392
1393out_connect:
1394        mutex_unlock(&con->sock_mutex);
1395        if (!test_bit(CF_INIT_PENDING, &con->flags))
1396                lowcomms_connect_sock(con);
1397        return;
1398}
1399
1400static void clean_one_writequeue(struct connection *con)
1401{
1402        struct writequeue_entry *e, *safe;
1403
1404        spin_lock(&con->writequeue_lock);
1405        list_for_each_entry_safe(e, safe, &con->writequeue, list) {
1406                list_del(&e->list);
1407                free_entry(e);
1408        }
1409        spin_unlock(&con->writequeue_lock);
1410}
1411
1412/* Called from recovery when it knows that a node has
1413   left the cluster */
1414int dlm_lowcomms_close(int nodeid)
1415{
1416        struct connection *con;
1417
1418        log_print("closing connection to node %d", nodeid);
1419        con = nodeid2con(nodeid, 0);
1420        if (con) {
1421                clear_bit(CF_CONNECT_PENDING, &con->flags);
1422                clear_bit(CF_WRITE_PENDING, &con->flags);
1423                set_bit(CF_CLOSE, &con->flags);
1424                if (cancel_work_sync(&con->swork))
1425                        log_print("canceled swork for node %d", nodeid);
1426                if (cancel_work_sync(&con->rwork))
1427                        log_print("canceled rwork for node %d", nodeid);
1428                clean_one_writequeue(con);
1429                close_connection(con, true);
1430        }
1431        return 0;
1432}
1433
1434/* Receive workqueue function */
1435static void process_recv_sockets(struct work_struct *work)
1436{
1437        struct connection *con = container_of(work, struct connection, rwork);
1438        int err;
1439
1440        clear_bit(CF_READ_PENDING, &con->flags);
1441        do {
1442                err = con->rx_action(con);
1443        } while (!err);
1444}
1445
1446/* Send workqueue function */
1447static void process_send_sockets(struct work_struct *work)
1448{
1449        struct connection *con = container_of(work, struct connection, swork);
1450
1451        if (test_and_clear_bit(CF_CONNECT_PENDING, &con->flags)) {
1452                con->connect_action(con);
1453                set_bit(CF_WRITE_PENDING, &con->flags);
1454        }
1455        if (test_and_clear_bit(CF_WRITE_PENDING, &con->flags))
1456                send_to_sock(con);
1457}
1458
1459
1460/* Discard all entries on the write queues */
1461static void clean_writequeues(void)
1462{
1463        foreach_conn(clean_one_writequeue);
1464}
1465
1466static void work_stop(void)
1467{
1468        destroy_workqueue(recv_workqueue);
1469        destroy_workqueue(send_workqueue);
1470}
1471
1472static int work_start(void)
1473{
1474        recv_workqueue = alloc_workqueue("dlm_recv",
1475                                         WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
1476        if (!recv_workqueue) {
1477                log_print("can't start dlm_recv");
1478                return -ENOMEM;
1479        }
1480
1481        send_workqueue = alloc_workqueue("dlm_send",
1482                                         WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
1483        if (!send_workqueue) {
1484                log_print("can't start dlm_send");
1485                destroy_workqueue(recv_workqueue);
1486                return -ENOMEM;
1487        }
1488
1489        return 0;
1490}
1491
1492static void stop_conn(struct connection *con)
1493{
1494        con->flags |= 0x0F;
1495        if (con->sock && con->sock->sk)
1496                con->sock->sk->sk_user_data = NULL;
1497}
1498
1499static void free_conn(struct connection *con)
1500{
1501        close_connection(con, true);
1502        if (con->othercon)
1503                kmem_cache_free(con_cache, con->othercon);
1504        hlist_del(&con->list);
1505        kmem_cache_free(con_cache, con);
1506}
1507
1508void dlm_lowcomms_stop(void)
1509{
1510        /* Set all the flags to prevent any
1511           socket activity.
1512        */
1513        mutex_lock(&connections_lock);
1514        dlm_allow_conn = 0;
1515        foreach_conn(stop_conn);
1516        mutex_unlock(&connections_lock);
1517
1518        work_stop();
1519
1520        mutex_lock(&connections_lock);
1521        clean_writequeues();
1522
1523        foreach_conn(free_conn);
1524
1525        mutex_unlock(&connections_lock);
1526        kmem_cache_destroy(con_cache);
1527}
1528
1529int dlm_lowcomms_start(void)
1530{
1531        int error = -EINVAL;
1532        struct connection *con;
1533        int i;
1534
1535        for (i = 0; i < CONN_HASH_SIZE; i++)
1536                INIT_HLIST_HEAD(&connection_hash[i]);
1537
1538        init_local();
1539        if (!dlm_local_count) {
1540                error = -ENOTCONN;
1541                log_print("no local IP address has been set");
1542                goto fail;
1543        }
1544
1545        error = -ENOMEM;
1546        con_cache = kmem_cache_create("dlm_conn", sizeof(struct connection),
1547                                      __alignof__(struct connection), 0,
1548                                      NULL);
1549        if (!con_cache)
1550                goto fail;
1551
1552        error = work_start();
1553        if (error)
1554                goto fail_destroy;
1555
1556        dlm_allow_conn = 1;
1557
1558        /* Start listening */
1559        if (dlm_config.ci_protocol == 0)
1560                error = tcp_listen_for_all();
1561        else
1562                error = sctp_listen_for_all();
1563        if (error)
1564                goto fail_unlisten;
1565
1566        return 0;
1567
1568fail_unlisten:
1569        dlm_allow_conn = 0;
1570        con = nodeid2con(0,0);
1571        if (con) {
1572                close_connection(con, false);
1573                kmem_cache_free(con_cache, con);
1574        }
1575fail_destroy:
1576        kmem_cache_destroy(con_cache);
1577fail:
1578        return error;
1579}
1580
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.