fs/dlm/lowcomms.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /******************************************************************************
   3 *******************************************************************************
   4 **
   5 **  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
   6 **  Copyright (C) 2004-2009 Red Hat, Inc.  All rights reserved.
   7 **
   8 **
   9 *******************************************************************************
  10 ******************************************************************************/
  11
  12 /*
  13  * lowcomms.c
  14  *
  15  * This is the "low-level" comms layer.
  16  *
  17  * It is responsible for sending/receiving messages
  18  * from other nodes in the cluster.
  19  *
  20  * Cluster nodes are referred to by their nodeids. nodeids are
  21  * simply 32 bit numbers to the locking module - if they need to
  22  * be expanded for the cluster infrastructure then that is its
  23  * responsibility. It is this layer's
  24  * responsibility to resolve these into IP address or
  25  * whatever it needs for inter-node communication.
  26  *
  27  * The comms level is two kernel threads that deal mainly with
  28  * the receiving of messages from other nodes and passing them
  29  * up to the mid-level comms layer (which understands the
  30  * message format) for execution by the locking core, and
  31  * a send thread which does all the setting up of connections
  32  * to remote nodes and the sending of data. Threads are not allowed
  33  * to send their own data because it may cause them to wait in times
  34  * of high load. Also, this way, the sending thread can collect together
  35  * messages bound for one node and send them in one block.
  36  *
  37  * lowcomms will choose to use either TCP or SCTP as its transport layer
  38  * depending on the configuration variable 'protocol'. This should be set
  39  * to 0 (default) for TCP or 1 for SCTP. It should be configured using a
  40  * cluster-wide mechanism as it must be the same on all nodes of the cluster
  41  * for the DLM to function.
  42  *
  43  */
  44
  45 #include <asm/ioctls.h>
  46 #include <net/sock.h>
  47 #include <net/tcp.h>
  48 #include <linux/pagemap.h>
  49 #include <linux/file.h>
  50 #include <linux/mutex.h>
  51 #include <linux/sctp.h>
  52 #include <linux/slab.h>
  53 #include <net/sctp/sctp.h>
  54 #include <net/ipv6.h>
  55
  56 #include "dlm_internal.h"
  57 #include "lowcomms.h"
  58 #include "midcomms.h"
  59 #include "config.h"
  60
  61 #define NEEDED_RMEM (4*1024*1024)
  62 #define CONN_HASH_SIZE 32
  63
  64 /* Number of messages to send before rescheduling */
  65 #define MAX_SEND_MSG_COUNT 25
  66 #define DLM_SHUTDOWN_WAIT_TIMEOUT msecs_to_jiffies(10000)
  67
  68 struct connection {
  69         struct socket *sock;    /* NULL if not connected */
  70         uint32_t nodeid;        /* So we know who we are in the list */
  71         struct mutex sock_mutex;
  72         unsigned long flags;
  73 #define CF_READ_PENDING 1
  74 #define CF_WRITE_PENDING 2
  75 #define CF_INIT_PENDING 4
  76 #define CF_IS_OTHERCON 5
  77 #define CF_CLOSE 6
  78 #define CF_APP_LIMITED 7
  79 #define CF_CLOSING 8
  80 #define CF_SHUTDOWN 9
  81         struct list_head writequeue;  /* List of outgoing writequeue_entries */
  82         spinlock_t writequeue_lock;
  83         int (*rx_action) (struct connection *); /* What to do when active */
  84         void (*connect_action) (struct connection *);   /* What to do to connect */
  85         void (*shutdown_action)(struct connection *con); /* What to do to shutdown */
  86         int retries;
  87 #define MAX_CONNECT_RETRIES 3
  88         struct hlist_node list;
  89         struct connection *othercon;
  90         struct work_struct rwork; /* Receive workqueue */
  91         struct work_struct swork; /* Send workqueue */
  92         wait_queue_head_t shutdown_wait; /* wait for graceful shutdown */
  93         unsigned char *rx_buf;
  94         int rx_buflen;
  95         int rx_leftover;
  96         struct rcu_head rcu;
  97 };
  98 #define sock2con(x) ((struct connection *)(x)->sk_user_data)
  99
 100 /* An entry waiting to be sent */
 101 struct writequeue_entry {
 102         struct list_head list;
 103         struct page *page;
 104         int offset;
 105         int len;
 106         int end;
 107         int users;
 108         struct connection *con;
 109 };
 110
 111 struct dlm_node_addr {
 112         struct list_head list;
 113         int nodeid;
 114         int addr_count;
 115         int curr_addr_index;
 116         struct sockaddr_storage *addr[DLM_MAX_ADDR_COUNT];
 117 };
 118
 119 static struct listen_sock_callbacks {
 120         void (*sk_error_report)(struct sock *);
 121         void (*sk_data_ready)(struct sock *);
 122         void (*sk_state_change)(struct sock *);
 123         void (*sk_write_space)(struct sock *);
 124 } listen_sock;
 125
 126 static LIST_HEAD(dlm_node_addrs);
 127 static DEFINE_SPINLOCK(dlm_node_addrs_spin);
 128
 129 static struct sockaddr_storage *dlm_local_addr[DLM_MAX_ADDR_COUNT];
 130 static int dlm_local_count;
 131 static int dlm_allow_conn;
 132
 133 /* Work queues */
 134 static struct workqueue_struct *recv_workqueue;
 135 static struct workqueue_struct *send_workqueue;
 136
 137 static struct hlist_head connection_hash[CONN_HASH_SIZE];
 138 static DEFINE_SPINLOCK(connections_lock);
 139 DEFINE_STATIC_SRCU(connections_srcu);
 140
 141 static void process_recv_sockets(struct work_struct *work);
 142 static void process_send_sockets(struct work_struct *work);
 143
 144
 145 /* This is deliberately very simple because most clusters have simple
 146    sequential nodeids, so we should be able to go straight to a connection
 147    struct in the array */
 148 static inline int nodeid_hash(int nodeid)
 149 {
 150         return nodeid & (CONN_HASH_SIZE-1);
 151 }
 152
 153 static struct connection *__find_con(int nodeid)
 154 {
 155         int r, idx;
 156         struct connection *con;
 157
 158         r = nodeid_hash(nodeid);
 159
 160         idx = srcu_read_lock(&connections_srcu);
 161         hlist_for_each_entry_rcu(con, &connection_hash[r], list) {
 162                 if (con->nodeid == nodeid) {
 163                         srcu_read_unlock(&connections_srcu, idx);
 164                         return con;
 165                 }
 166         }
 167         srcu_read_unlock(&connections_srcu, idx);
 168
 169         return NULL;
 170 }
 171
 172 /*
 173  * If 'allocation' is zero then we don't attempt to create a new
 174  * connection structure for this node.
 175  */
 176 static struct connection *nodeid2con(int nodeid, gfp_t alloc)
 177 {
 178         struct connection *con = NULL;
 179         int r;
 180
 181         con = __find_con(nodeid);
 182         if (con || !alloc)
 183                 return con;
 184
 185         con = kzalloc(sizeof(*con), alloc);
 186         if (!con)
 187                 return NULL;
 188
 189         con->rx_buflen = dlm_config.ci_buffer_size;
 190         con->rx_buf = kmalloc(con->rx_buflen, GFP_NOFS);
 191         if (!con->rx_buf) {
 192                 kfree(con);
 193                 return NULL;
 194         }
 195
 196         con->nodeid = nodeid;
 197         mutex_init(&con->sock_mutex);
 198         INIT_LIST_HEAD(&con->writequeue);
 199         spin_lock_init(&con->writequeue_lock);
 200         INIT_WORK(&con->swork, process_send_sockets);
 201         INIT_WORK(&con->rwork, process_recv_sockets);
 202         init_waitqueue_head(&con->shutdown_wait);
 203
 204         /* Setup action pointers for child sockets */
 205         if (con->nodeid) {
 206                 struct connection *zerocon = __find_con(0);
 207
 208                 con->connect_action = zerocon->connect_action;
 209                 if (!con->rx_action)
 210                         con->rx_action = zerocon->rx_action;
 211         }
 212
 213         r = nodeid_hash(nodeid);
 214
 215         spin_lock(&connections_lock);
 216         hlist_add_head_rcu(&con->list, &connection_hash[r]);
 217         spin_unlock(&connections_lock);
 218
 219         return con;
 220 }
 221
 222 /* Loop round all connections */
 223 static void foreach_conn(void (*conn_func)(struct connection *c))
 224 {
 225         int i, idx;
 226         struct connection *con;
 227
 228         idx = srcu_read_lock(&connections_srcu);
 229         for (i = 0; i < CONN_HASH_SIZE; i++) {
 230                 hlist_for_each_entry_rcu(con, &connection_hash[i], list)
 231                         conn_func(con);
 232         }
 233         srcu_read_unlock(&connections_srcu, idx);
 234 }
 235
 236 static struct dlm_node_addr *find_node_addr(int nodeid)
 237 {
 238         struct dlm_node_addr *na;
 239
 240         list_for_each_entry(na, &dlm_node_addrs, list) {
 241                 if (na->nodeid == nodeid)
 242                         return na;
 243         }
 244         return NULL;
 245 }
 246
 247 static int addr_compare(struct sockaddr_storage *x, struct sockaddr_storage *y)
 248 {
 249         switch (x->ss_family) {
 250         case AF_INET: {
 251                 struct sockaddr_in *sinx = (struct sockaddr_in *)x;
 252                 struct sockaddr_in *siny = (struct sockaddr_in *)y;
 253                 if (sinx->sin_addr.s_addr != siny->sin_addr.s_addr)
 254                         return 0;
 255                 if (sinx->sin_port != siny->sin_port)
 256                         return 0;
 257                 break;
 258         }
 259         case AF_INET6: {
 260                 struct sockaddr_in6 *sinx = (struct sockaddr_in6 *)x;
 261                 struct sockaddr_in6 *siny = (struct sockaddr_in6 *)y;
 262                 if (!ipv6_addr_equal(&sinx->sin6_addr, &siny->sin6_addr))
 263                         return 0;
 264                 if (sinx->sin6_port != siny->sin6_port)
 265                         return 0;
 266                 break;
 267         }
 268         default:
 269                 return 0;
 270         }
 271         return 1;
 272 }
 273
 274 static int nodeid_to_addr(int nodeid, struct sockaddr_storage *sas_out,
 275                           struct sockaddr *sa_out, bool try_new_addr)
 276 {
 277         struct sockaddr_storage sas;
 278         struct dlm_node_addr *na;
 279
 280         if (!dlm_local_count)
 281                 return -1;
 282
 283         spin_lock(&dlm_node_addrs_spin);
 284         na = find_node_addr(nodeid);
 285         if (na && na->addr_count) {
 286                 memcpy(&sas, na->addr[na->curr_addr_index],
 287                        sizeof(struct sockaddr_storage));
 288
 289                 if (try_new_addr) {
 290                         na->curr_addr_index++;
 291                         if (na->curr_addr_index == na->addr_count)
 292                                 na->curr_addr_index = 0;
 293                 }
 294         }
 295         spin_unlock(&dlm_node_addrs_spin);
 296
 297         if (!na)
 298                 return -EEXIST;
 299
 300         if (!na->addr_count)
 301                 return -ENOENT;
 302
 303         if (sas_out)
 304                 memcpy(sas_out, &sas, sizeof(struct sockaddr_storage));
 305
 306         if (!sa_out)
 307                 return 0;
 308
 309         if (dlm_local_addr[0]->ss_family == AF_INET) {
 310                 struct sockaddr_in *in4  = (struct sockaddr_in *) &sas;
 311                 struct sockaddr_in *ret4 = (struct sockaddr_in *) sa_out;
 312                 ret4->sin_addr.s_addr = in4->sin_addr.s_addr;
 313         } else {
 314                 struct sockaddr_in6 *in6  = (struct sockaddr_in6 *) &sas;
 315                 struct sockaddr_in6 *ret6 = (struct sockaddr_in6 *) sa_out;
 316                 ret6->sin6_addr = in6->sin6_addr;
 317         }
 318
 319         return 0;
 320 }
 321
 322 static int addr_to_nodeid(struct sockaddr_storage *addr, int *nodeid)
 323 {
 324         struct dlm_node_addr *na;
 325         int rv = -EEXIST;
 326         int addr_i;
 327
 328         spin_lock(&dlm_node_addrs_spin);
 329         list_for_each_entry(na, &dlm_node_addrs, list) {
 330                 if (!na->addr_count)
 331                         continue;
 332
 333                 for (addr_i = 0; addr_i < na->addr_count; addr_i++) {
 334                         if (addr_compare(na->addr[addr_i], addr)) {
 335                                 *nodeid = na->nodeid;
 336                                 rv = 0;
 337                                 goto unlock;
 338                         }
 339                 }
 340         }
 341 unlock:
 342         spin_unlock(&dlm_node_addrs_spin);
 343         return rv;
 344 }
 345
 346 int dlm_lowcomms_addr(int nodeid, struct sockaddr_storage *addr, int len)
 347 {
 348         struct sockaddr_storage *new_addr;
 349         struct dlm_node_addr *new_node, *na;
 350
 351         new_node = kzalloc(sizeof(struct dlm_node_addr), GFP_NOFS);
 352         if (!new_node)
 353                 return -ENOMEM;
 354
 355         new_addr = kzalloc(sizeof(struct sockaddr_storage), GFP_NOFS);
 356         if (!new_addr) {
 357                 kfree(new_node);
 358                 return -ENOMEM;
 359         }
 360
 361         memcpy(new_addr, addr, len);
 362
 363         spin_lock(&dlm_node_addrs_spin);
 364         na = find_node_addr(nodeid);
 365         if (!na) {
 366                 new_node->nodeid = nodeid;
 367                 new_node->addr[0] = new_addr;
 368                 new_node->addr_count = 1;
 369                 list_add(&new_node->list, &dlm_node_addrs);
 370                 spin_unlock(&dlm_node_addrs_spin);
 371                 return 0;
 372         }
 373
 374         if (na->addr_count >= DLM_MAX_ADDR_COUNT) {
 375                 spin_unlock(&dlm_node_addrs_spin);
 376                 kfree(new_addr);
 377                 kfree(new_node);
 378                 return -ENOSPC;
 379         }
 380
 381         na->addr[na->addr_count++] = new_addr;
 382         spin_unlock(&dlm_node_addrs_spin);
 383         kfree(new_node);
 384         return 0;
 385 }
 386
 387 /* Data available on socket or listen socket received a connect */
 388 static void lowcomms_data_ready(struct sock *sk)
 389 {
 390         struct connection *con;
 391
 392         read_lock_bh(&sk->sk_callback_lock);
 393         con = sock2con(sk);
 394         if (con && !test_and_set_bit(CF_READ_PENDING, &con->flags))
 395                 queue_work(recv_workqueue, &con->rwork);
 396         read_unlock_bh(&sk->sk_callback_lock);
 397 }
 398
 399 static void lowcomms_write_space(struct sock *sk)
 400 {
 401         struct connection *con;
 402
 403         read_lock_bh(&sk->sk_callback_lock);
 404         con = sock2con(sk);
 405         if (!con)
 406                 goto out;
 407
 408         clear_bit(SOCK_NOSPACE, &con->sock->flags);
 409
 410         if (test_and_clear_bit(CF_APP_LIMITED, &con->flags)) {
 411                 con->sock->sk->sk_write_pending--;
 412                 clear_bit(SOCKWQ_ASYNC_NOSPACE, &con->sock->flags);
 413         }
 414
 415         queue_work(send_workqueue, &con->swork);
 416 out:
 417         read_unlock_bh(&sk->sk_callback_lock);
 418 }
 419
 420 static inline void lowcomms_connect_sock(struct connection *con)
 421 {
 422         if (test_bit(CF_CLOSE, &con->flags))
 423                 return;
 424         queue_work(send_workqueue, &con->swork);
 425         cond_resched();
 426 }
 427
 428 static void lowcomms_state_change(struct sock *sk)
 429 {
 430         /* SCTP layer is not calling sk_data_ready when the connection
 431          * is done, so we catch the signal through here. Also, it
 432          * doesn't switch socket state when entering shutdown, so we
 433          * skip the write in that case.
 434          */
 435         if (sk->sk_shutdown) {
 436                 if (sk->sk_shutdown == RCV_SHUTDOWN)
 437                         lowcomms_data_ready(sk);
 438         } else if (sk->sk_state == TCP_ESTABLISHED) {
 439                 lowcomms_write_space(sk);
 440         }
 441 }
 442
 443 int dlm_lowcomms_connect_node(int nodeid)
 444 {
 445         struct connection *con;
 446
 447         if (nodeid == dlm_our_nodeid())
 448                 return 0;
 449
 450         con = nodeid2con(nodeid, GFP_NOFS);
 451         if (!con)
 452                 return -ENOMEM;
 453         lowcomms_connect_sock(con);
 454         return 0;
 455 }
 456
 457 static void lowcomms_error_report(struct sock *sk)
 458 {
 459         struct connection *con;
 460         struct sockaddr_storage saddr;
 461         void (*orig_report)(struct sock *) = NULL;
 462
 463         read_lock_bh(&sk->sk_callback_lock);
 464         con = sock2con(sk);
 465         if (con == NULL)
 466                 goto out;
 467
 468         orig_report = listen_sock.sk_error_report;
 469         if (con->sock == NULL ||
 470             kernel_getpeername(con->sock, (struct sockaddr *)&saddr) < 0) {
 471                 printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
 472                                    "sending to node %d, port %d, "
 473                                    "sk_err=%d/%d\n", dlm_our_nodeid(),
 474                                    con->nodeid, dlm_config.ci_tcp_port,
 475                                    sk->sk_err, sk->sk_err_soft);
 476         } else if (saddr.ss_family == AF_INET) {
 477                 struct sockaddr_in *sin4 = (struct sockaddr_in *)&saddr;
 478
 479                 printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
 480                                    "sending to node %d at %pI4, port %d, "
 481                                    "sk_err=%d/%d\n", dlm_our_nodeid(),
 482                                    con->nodeid, &sin4->sin_addr.s_addr,
 483                                    dlm_config.ci_tcp_port, sk->sk_err,
 484                                    sk->sk_err_soft);
 485         } else {
 486                 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&saddr;
 487
 488                 printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
 489                                    "sending to node %d at %u.%u.%u.%u, "
 490                                    "port %d, sk_err=%d/%d\n", dlm_our_nodeid(),
 491                                    con->nodeid, sin6->sin6_addr.s6_addr32[0],
 492                                    sin6->sin6_addr.s6_addr32[1],
 493                                    sin6->sin6_addr.s6_addr32[2],
 494                                    sin6->sin6_addr.s6_addr32[3],
 495                                    dlm_config.ci_tcp_port, sk->sk_err,
 496                                    sk->sk_err_soft);
 497         }
 498 out:
 499         read_unlock_bh(&sk->sk_callback_lock);
 500         if (orig_report)
 501                 orig_report(sk);
 502 }
 503
 504 /* Note: sk_callback_lock must be locked before calling this function. */
 505 static void save_listen_callbacks(struct socket *sock)
 506 {
 507         struct sock *sk = sock->sk;
 508
 509         listen_sock.sk_data_ready = sk->sk_data_ready;
 510         listen_sock.sk_state_change = sk->sk_state_change;
 511         listen_sock.sk_write_space = sk->sk_write_space;
 512         listen_sock.sk_error_report = sk->sk_error_report;
 513 }
 514
 515 static void restore_callbacks(struct socket *sock)
 516 {
 517         struct sock *sk = sock->sk;
 518
 519         write_lock_bh(&sk->sk_callback_lock);
 520         sk->sk_user_data = NULL;
 521         sk->sk_data_ready = listen_sock.sk_data_ready;
 522         sk->sk_state_change = listen_sock.sk_state_change;
 523         sk->sk_write_space = listen_sock.sk_write_space;
 524         sk->sk_error_report = listen_sock.sk_error_report;
 525         write_unlock_bh(&sk->sk_callback_lock);
 526 }
 527
 528 /* Make a socket active */
 529 static void add_sock(struct socket *sock, struct connection *con)
 530 {
 531         struct sock *sk = sock->sk;
 532
 533         write_lock_bh(&sk->sk_callback_lock);
 534         con->sock = sock;
 535
 536         sk->sk_user_data = con;
 537         /* Install a data_ready callback */
 538         sk->sk_data_ready = lowcomms_data_ready;
 539         sk->sk_write_space = lowcomms_write_space;
 540         sk->sk_state_change = lowcomms_state_change;
 541         sk->sk_allocation = GFP_NOFS;
 542         sk->sk_error_report = lowcomms_error_report;
 543         write_unlock_bh(&sk->sk_callback_lock);
 544 }
 545
 546 /* Add the port number to an IPv6 or 4 sockaddr and return the address
 547    length */
 548 static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port,
 549                           int *addr_len)
 550 {
 551         saddr->ss_family =  dlm_local_addr[0]->ss_family;
 552         if (saddr->ss_family == AF_INET) {
 553                 struct sockaddr_in *in4_addr = (struct sockaddr_in *)saddr;
 554                 in4_addr->sin_port = cpu_to_be16(port);
 555                 *addr_len = sizeof(struct sockaddr_in);
 556                 memset(&in4_addr->sin_zero, 0, sizeof(in4_addr->sin_zero));
 557         } else {
 558                 struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)saddr;
 559                 in6_addr->sin6_port = cpu_to_be16(port);
 560                 *addr_len = sizeof(struct sockaddr_in6);
 561         }
 562         memset((char *)saddr + *addr_len, 0, sizeof(struct sockaddr_storage) - *addr_len);
 563 }
 564
 565 /* Close a remote connection and tidy up */
 566 static void close_connection(struct connection *con, bool and_other,
 567                              bool tx, bool rx)
 568 {
 569         bool closing = test_and_set_bit(CF_CLOSING, &con->flags);
 570
 571         if (tx && !closing && cancel_work_sync(&con->swork)) {
 572                 log_print("canceled swork for node %d", con->nodeid);
 573                 clear_bit(CF_WRITE_PENDING, &con->flags);
 574         }
 575         if (rx && !closing && cancel_work_sync(&con->rwork)) {
 576                 log_print("canceled rwork for node %d", con->nodeid);
 577                 clear_bit(CF_READ_PENDING, &con->flags);
 578         }
 579
 580         mutex_lock(&con->sock_mutex);
 581         if (con->sock) {
 582                 restore_callbacks(con->sock);
 583                 sock_release(con->sock);
 584                 con->sock = NULL;
 585         }
 586         if (con->othercon && and_other) {
 587                 /* Will only re-enter once. */
 588                 close_connection(con->othercon, false, true, true);
 589         }
 590
 591         con->rx_leftover = 0;
 592         con->retries = 0;
 593         mutex_unlock(&con->sock_mutex);
 594         clear_bit(CF_CLOSING, &con->flags);
 595 }
 596
 597 static void shutdown_connection(struct connection *con)
 598 {
 599         int ret;
 600
 601         if (cancel_work_sync(&con->swork)) {
 602                 log_print("canceled swork for node %d", con->nodeid);
 603                 clear_bit(CF_WRITE_PENDING, &con->flags);
 604         }
 605
 606         mutex_lock(&con->sock_mutex);
 607         /* nothing to shutdown */
 608         if (!con->sock) {
 609                 mutex_unlock(&con->sock_mutex);
 610                 return;
 611         }
 612
 613         set_bit(CF_SHUTDOWN, &con->flags);
 614         ret = kernel_sock_shutdown(con->sock, SHUT_WR);
 615         mutex_unlock(&con->sock_mutex);
 616         if (ret) {
 617                 log_print("Connection %p failed to shutdown: %d will force close",
 618                           con, ret);
 619                 goto force_close;
 620         } else {
 621                 ret = wait_event_timeout(con->shutdown_wait,
 622                                          !test_bit(CF_SHUTDOWN, &con->flags),
 623                                          DLM_SHUTDOWN_WAIT_TIMEOUT);
 624                 if (ret == 0) {
 625                         log_print("Connection %p shutdown timed out, will force close",
 626                                   con);
 627                         goto force_close;
 628                 }
 629         }
 630
 631         return;
 632
 633 force_close:
 634         clear_bit(CF_SHUTDOWN, &con->flags);
 635         close_connection(con, false, true, true);
 636 }
 637
 638 static void dlm_tcp_shutdown(struct connection *con)
 639 {
 640         if (con->othercon)
 641                 shutdown_connection(con->othercon);
 642         shutdown_connection(con);
 643 }
 644
 645 static int con_realloc_receive_buf(struct connection *con, int newlen)
 646 {
 647         unsigned char *newbuf;
 648
 649         newbuf = kmalloc(newlen, GFP_NOFS);
 650         if (!newbuf)
 651                 return -ENOMEM;
 652
 653         /* copy any leftover from last receive */
 654         if (con->rx_leftover)
 655                 memmove(newbuf, con->rx_buf, con->rx_leftover);
 656
 657         /* swap to new buffer space */
 658         kfree(con->rx_buf);
 659         con->rx_buflen = newlen;
 660         con->rx_buf = newbuf;
 661
 662         return 0;
 663 }
 664
 665 /* Data received from remote end */
 666 static int receive_from_sock(struct connection *con)
 667 {
 668         int call_again_soon = 0;
 669         struct msghdr msg;
 670         struct kvec iov;
 671         int ret, buflen;
 672
 673         mutex_lock(&con->sock_mutex);
 674
 675         if (con->sock == NULL) {
 676                 ret = -EAGAIN;
 677                 goto out_close;
 678         }
 679
 680         if (con->nodeid == 0) {
 681                 ret = -EINVAL;
 682                 goto out_close;
 683         }
 684
 685         /* realloc if we get new buffer size to read out */
 686         buflen = dlm_config.ci_buffer_size;
 687         if (con->rx_buflen != buflen && con->rx_leftover <= buflen) {
 688                 ret = con_realloc_receive_buf(con, buflen);
 689                 if (ret < 0)
 690                         goto out_resched;
 691         }
 692
 693         /* calculate new buffer parameter regarding last receive and
 694          * possible leftover bytes
 695          */
 696         iov.iov_base = con->rx_buf + con->rx_leftover;
 697         iov.iov_len = con->rx_buflen - con->rx_leftover;
 698
 699         memset(&msg, 0, sizeof(msg));
 700         msg.msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL;
 701         ret = kernel_recvmsg(con->sock, &msg, &iov, 1, iov.iov_len,
 702                              msg.msg_flags);
 703         if (ret <= 0)
 704                 goto out_close;
 705         else if (ret == iov.iov_len)
 706                 call_again_soon = 1;
 707
 708         /* new buflen according readed bytes and leftover from last receive */
 709         buflen = ret + con->rx_leftover;
 710         ret = dlm_process_incoming_buffer(con->nodeid, con->rx_buf, buflen);
 711         if (ret < 0)
 712                 goto out_close;
 713
 714         /* calculate leftover bytes from process and put it into begin of
 715          * the receive buffer, so next receive we have the full message
 716          * at the start address of the receive buffer.
 717          */
 718         con->rx_leftover = buflen - ret;
 719         if (con->rx_leftover) {
 720                 memmove(con->rx_buf, con->rx_buf + ret,
 721                         con->rx_leftover);
 722                 call_again_soon = true;
 723         }
 724
 725         if (call_again_soon)
 726                 goto out_resched;
 727
 728         mutex_unlock(&con->sock_mutex);
 729         return 0;
 730
 731 out_resched:
 732         if (!test_and_set_bit(CF_READ_PENDING, &con->flags))
 733                 queue_work(recv_workqueue, &con->rwork);
 734         mutex_unlock(&con->sock_mutex);
 735         return -EAGAIN;
 736
 737 out_close:
 738         mutex_unlock(&con->sock_mutex);
 739         if (ret != -EAGAIN) {
 740                 /* Reconnect when there is something to send */
 741                 close_connection(con, false, true, false);
 742                 if (ret == 0) {
 743                         log_print("connection %p got EOF from %d",
 744                                   con, con->nodeid);
 745                         /* handling for tcp shutdown */
 746                         clear_bit(CF_SHUTDOWN, &con->flags);
 747                         wake_up(&con->shutdown_wait);
 748                         /* signal to breaking receive worker */
 749                         ret = -1;
 750                 }
 751         }
 752         return ret;
 753 }
 754
 755 /* Listening socket is busy, accept a connection */
 756 static int accept_from_sock(struct connection *con)
 757 {
 758         int result;
 759         struct sockaddr_storage peeraddr;
 760         struct socket *newsock;
 761         int len;
 762         int nodeid;
 763         struct connection *newcon;
 764         struct connection *addcon;
 765         unsigned int mark;
 766
 767         if (!dlm_allow_conn) {
 768                 return -1;
 769         }
 770
 771         mutex_lock_nested(&con->sock_mutex, 0);
 772
 773         if (!con->sock) {
 774                 mutex_unlock(&con->sock_mutex);
 775                 return -ENOTCONN;
 776         }
 777
 778         result = kernel_accept(con->sock, &newsock, O_NONBLOCK);
 779         if (result < 0)
 780                 goto accept_err;
 781
 782         /* Get the connected socket's peer */
 783         memset(&peeraddr, 0, sizeof(peeraddr));
 784         len = newsock->ops->getname(newsock, (struct sockaddr *)&peeraddr, 2);
 785         if (len < 0) {
 786                 result = -ECONNABORTED;
 787                 goto accept_err;
 788         }
 789
 790         /* Get the new node's NODEID */
 791         make_sockaddr(&peeraddr, 0, &len);
 792         if (addr_to_nodeid(&peeraddr, &nodeid)) {
 793                 unsigned char *b=(unsigned char *)&peeraddr;
 794                 log_print("connect from non cluster node");
 795                 print_hex_dump_bytes("ss: ", DUMP_PREFIX_NONE,
 796                                      b, sizeof(struct sockaddr_storage));
 797                 sock_release(newsock);
 798                 mutex_unlock(&con->sock_mutex);
 799                 return -1;
 800         }
 801
 802         dlm_comm_mark(nodeid, &mark);
 803         sock_set_mark(newsock->sk, mark);
 804
 805         log_print("got connection from %d", nodeid);
 806
 807         /*  Check to see if we already have a connection to this node. This
 808          *  could happen if the two nodes initiate a connection at roughly
 809          *  the same time and the connections cross on the wire.
 810          *  In this case we store the incoming one in "othercon"
 811          */
 812         newcon = nodeid2con(nodeid, GFP_NOFS);
 813         if (!newcon) {
 814                 result = -ENOMEM;
 815                 goto accept_err;
 816         }
 817         mutex_lock_nested(&newcon->sock_mutex, 1);
 818         if (newcon->sock) {
 819                 struct connection *othercon = newcon->othercon;
 820
 821                 if (!othercon) {
 822                         othercon = kzalloc(sizeof(*othercon), GFP_NOFS);
 823                         if (!othercon) {
 824                                 log_print("failed to allocate incoming socket");
 825                                 mutex_unlock(&newcon->sock_mutex);
 826                                 result = -ENOMEM;
 827                                 goto accept_err;
 828                         }
 829
 830                         othercon->rx_buflen = dlm_config.ci_buffer_size;
 831                         othercon->rx_buf = kmalloc(othercon->rx_buflen, GFP_NOFS);
 832                         if (!othercon->rx_buf) {
 833                                 mutex_unlock(&newcon->sock_mutex);
 834                                 kfree(othercon);
 835                                 log_print("failed to allocate incoming socket receive buffer");
 836                                 result = -ENOMEM;
 837                                 goto accept_err;
 838                         }
 839
 840                         othercon->nodeid = nodeid;
 841                         othercon->rx_action = receive_from_sock;
 842                         mutex_init(&othercon->sock_mutex);
 843                         INIT_LIST_HEAD(&othercon->writequeue);
 844                         spin_lock_init(&othercon->writequeue_lock);
 845                         INIT_WORK(&othercon->swork, process_send_sockets);
 846                         INIT_WORK(&othercon->rwork, process_recv_sockets);
 847                         init_waitqueue_head(&othercon->shutdown_wait);
 848                         set_bit(CF_IS_OTHERCON, &othercon->flags);
 849                 } else {
 850                         /* close other sock con if we have something new */
 851                         close_connection(othercon, false, true, false);
 852                 }
 853
 854                 mutex_lock_nested(&othercon->sock_mutex, 2);
 855                 newcon->othercon = othercon;
 856                 add_sock(newsock, othercon);
 857                 addcon = othercon;
 858                 mutex_unlock(&othercon->sock_mutex);
 859         }
 860         else {
 861                 newcon->rx_action = receive_from_sock;
 862                 /* accept copies the sk after we've saved the callbacks, so we
 863                    don't want to save them a second time or comm errors will
 864                    result in calling sk_error_report recursively. */
 865                 add_sock(newsock, newcon);
 866                 addcon = newcon;
 867         }
 868
 869         mutex_unlock(&newcon->sock_mutex);
 870
 871         /*
 872          * Add it to the active queue in case we got data
 873          * between processing the accept adding the socket
 874          * to the read_sockets list
 875          */
 876         if (!test_and_set_bit(CF_READ_PENDING, &addcon->flags))
 877                 queue_work(recv_workqueue, &addcon->rwork);
 878         mutex_unlock(&con->sock_mutex);
 879
 880         return 0;
 881
 882 accept_err:
 883         mutex_unlock(&con->sock_mutex);
 884         if (newsock)
 885                 sock_release(newsock);
 886
 887         if (result != -EAGAIN)
 888                 log_print("error accepting connection from node: %d", result);
 889         return result;
 890 }
 891
 892 static void free_entry(struct writequeue_entry *e)
 893 {
 894         __free_page(e->page);
 895         kfree(e);
 896 }
 897
 898 /*
 899  * writequeue_entry_complete - try to delete and free write queue entry
 900  * @e: write queue entry to try to delete
 901  * @completed: bytes completed
 902  *
 903  * writequeue_lock must be held.
 904  */
 905 static void writequeue_entry_complete(struct writequeue_entry *e, int completed)
 906 {
 907         e->offset += completed;
 908         e->len -= completed;
 909
 910         if (e->len == 0 && e->users == 0) {
 911                 list_del(&e->list);
 912                 free_entry(e);
 913         }
 914 }
 915
 916 /*
 917  * sctp_bind_addrs - bind a SCTP socket to all our addresses
 918  */
 919 static int sctp_bind_addrs(struct connection *con, uint16_t port)
 920 {
 921         struct sockaddr_storage localaddr;
 922         struct sockaddr *addr = (struct sockaddr *)&localaddr;
 923         int i, addr_len, result = 0;
 924
 925         for (i = 0; i < dlm_local_count; i++) {
 926                 memcpy(&localaddr, dlm_local_addr[i], sizeof(localaddr));
 927                 make_sockaddr(&localaddr, port, &addr_len);
 928
 929                 if (!i)
 930                         result = kernel_bind(con->sock, addr, addr_len);
 931                 else
 932                         result = sock_bind_add(con->sock->sk, addr, addr_len);
 933
 934                 if (result < 0) {
 935                         log_print("Can't bind to %d addr number %d, %d.\n",
 936                                   port, i + 1, result);
 937                         break;
 938                 }
 939         }
 940         return result;
 941 }
 942
 943 /* Initiate an SCTP association.
 944    This is a special case of send_to_sock() in that we don't yet have a
 945    peeled-off socket for this association, so we use the listening socket
 946    and add the primary IP address of the remote node.
 947  */
 948 static void sctp_connect_to_sock(struct connection *con)
 949 {
 950         struct sockaddr_storage daddr;
 951         int result;
 952         int addr_len;
 953         struct socket *sock;
 954         unsigned int mark;
 955
 956         if (con->nodeid == 0) {
 957                 log_print("attempt to connect sock 0 foiled");
 958                 return;
 959         }
 960
 961         dlm_comm_mark(con->nodeid, &mark);
 962
 963         mutex_lock(&con->sock_mutex);
 964
 965         /* Some odd races can cause double-connects, ignore them */
 966         if (con->retries++ > MAX_CONNECT_RETRIES)
 967                 goto out;
 968
 969         if (con->sock) {
 970                 log_print("node %d already connected.", con->nodeid);
 971                 goto out;
 972         }
 973
 974         memset(&daddr, 0, sizeof(daddr));
 975         result = nodeid_to_addr(con->nodeid, &daddr, NULL, true);
 976         if (result < 0) {
 977                 log_print("no address for nodeid %d", con->nodeid);
 978                 goto out;
 979         }
 980
 981         /* Create a socket to communicate with */
 982         result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
 983                                   SOCK_STREAM, IPPROTO_SCTP, &sock);
 984         if (result < 0)
 985                 goto socket_err;
 986
 987         sock_set_mark(sock->sk, mark);
 988
 989         con->rx_action = receive_from_sock;
 990         con->connect_action = sctp_connect_to_sock;
 991         add_sock(sock, con);
 992
 993         /* Bind to all addresses. */
 994         if (sctp_bind_addrs(con, 0))
 995                 goto bind_err;
 996
 997         make_sockaddr(&daddr, dlm_config.ci_tcp_port, &addr_len);
 998
 999         log_print("connecting to %d", con->nodeid);
1000
1001         /* Turn off Nagle's algorithm */
1002         sctp_sock_set_nodelay(sock->sk);
1003
1004         /*
1005          * Make sock->ops->connect() function return in specified time,
1006          * since O_NONBLOCK argument in connect() function does not work here,
1007          * then, we should restore the default value of this attribute.
1008          */
1009         sock_set_sndtimeo(sock->sk, 5);
1010         result = sock->ops->connect(sock, (struct sockaddr *)&daddr, addr_len,
1011                                    0);
1012         sock_set_sndtimeo(sock->sk, 0);
1013
1014         if (result == -EINPROGRESS)
1015                 result = 0;
1016         if (result == 0)
1017                 goto out;
1018
1019 bind_err:
1020         con->sock = NULL;
1021         sock_release(sock);
1022
1023 socket_err:
1024         /*
1025          * Some errors are fatal and this list might need adjusting. For other
1026          * errors we try again until the max number of retries is reached.
1027          */
1028         if (result != -EHOSTUNREACH &&
1029             result != -ENETUNREACH &&
1030             result != -ENETDOWN &&
1031             result != -EINVAL &&
1032             result != -EPROTONOSUPPORT) {
1033                 log_print("connect %d try %d error %d", con->nodeid,
1034                           con->retries, result);
1035                 mutex_unlock(&con->sock_mutex);
1036                 msleep(1000);
1037                 lowcomms_connect_sock(con);
1038                 return;
1039         }
1040
1041 out:
1042         mutex_unlock(&con->sock_mutex);
1043 }
1044
1045 /* Connect a new socket to its peer */
1046 static void tcp_connect_to_sock(struct connection *con)
1047 {
1048         struct sockaddr_storage saddr, src_addr;
1049         int addr_len;
1050         struct socket *sock = NULL;
1051         unsigned int mark;
1052         int result;
1053
1054         if (con->nodeid == 0) {
1055                 log_print("attempt to connect sock 0 foiled");
1056                 return;
1057         }
1058
1059         dlm_comm_mark(con->nodeid, &mark);
1060
1061         mutex_lock(&con->sock_mutex);
1062         if (con->retries++ > MAX_CONNECT_RETRIES)
1063                 goto out;
1064
1065         /* Some odd races can cause double-connects, ignore them */
1066         if (con->sock)
1067                 goto out;
1068
1069         /* Create a socket to communicate with */
1070         result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
1071                                   SOCK_STREAM, IPPROTO_TCP, &sock);
1072         if (result < 0)
1073                 goto out_err;
1074
1075         sock_set_mark(sock->sk, mark);
1076
1077         memset(&saddr, 0, sizeof(saddr));
1078         result = nodeid_to_addr(con->nodeid, &saddr, NULL, false);
1079         if (result < 0) {
1080                 log_print("no address for nodeid %d", con->nodeid);
1081                 goto out_err;
1082         }
1083
1084         con->rx_action = receive_from_sock;
1085         con->connect_action = tcp_connect_to_sock;
1086         con->shutdown_action = dlm_tcp_shutdown;
1087         add_sock(sock, con);
1088
1089         /* Bind to our cluster-known address connecting to avoid
1090            routing problems */
1091         memcpy(&src_addr, dlm_local_addr[0], sizeof(src_addr));
1092         make_sockaddr(&src_addr, 0, &addr_len);
1093         result = sock->ops->bind(sock, (struct sockaddr *) &src_addr,
1094                                  addr_len);
1095         if (result < 0) {
1096                 log_print("could not bind for connect: %d", result);
1097                 /* This *may* not indicate a critical error */
1098         }
1099
1100         make_sockaddr(&saddr, dlm_config.ci_tcp_port, &addr_len);
1101
1102         log_print("connecting to %d", con->nodeid);
1103
1104         /* Turn off Nagle's algorithm */
1105         tcp_sock_set_nodelay(sock->sk);
1106
1107         result = sock->ops->connect(sock, (struct sockaddr *)&saddr, addr_len,
1108                                    O_NONBLOCK);
1109         if (result == -EINPROGRESS)
1110                 result = 0;
1111         if (result == 0)
1112                 goto out;
1113
1114 out_err:
1115         if (con->sock) {
1116                 sock_release(con->sock);
1117                 con->sock = NULL;
1118         } else if (sock) {
1119                 sock_release(sock);
1120         }
1121         /*
1122          * Some errors are fatal and this list might need adjusting. For other
1123          * errors we try again until the max number of retries is reached.
1124          */
1125         if (result != -EHOSTUNREACH &&
1126             result != -ENETUNREACH &&
1127             result != -ENETDOWN &&
1128             result != -EINVAL &&
1129             result != -EPROTONOSUPPORT) {
1130                 log_print("connect %d try %d error %d", con->nodeid,
1131                           con->retries, result);
1132                 mutex_unlock(&con->sock_mutex);
1133                 msleep(1000);
1134                 lowcomms_connect_sock(con);
1135                 return;
1136         }
1137 out:
1138         mutex_unlock(&con->sock_mutex);
1139         return;
1140 }
1141
1142 static struct socket *tcp_create_listen_sock(struct connection *con,
1143                                              struct sockaddr_storage *saddr)
1144 {
1145         struct socket *sock = NULL;
1146         int result = 0;
1147         int addr_len;
1148
1149         if (dlm_local_addr[0]->ss_family == AF_INET)
1150                 addr_len = sizeof(struct sockaddr_in);
1151         else
1152                 addr_len = sizeof(struct sockaddr_in6);
1153
1154         /* Create a socket to communicate with */
1155         result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
1156                                   SOCK_STREAM, IPPROTO_TCP, &sock);
1157         if (result < 0) {
1158                 log_print("Can't create listening comms socket");
1159                 goto create_out;
1160         }
1161
1162         sock_set_mark(sock->sk, dlm_config.ci_mark);
1163
1164         /* Turn off Nagle's algorithm */
1165         tcp_sock_set_nodelay(sock->sk);
1166
1167         sock_set_reuseaddr(sock->sk);
1168
1169         write_lock_bh(&sock->sk->sk_callback_lock);
1170         sock->sk->sk_user_data = con;
1171         save_listen_callbacks(sock);
1172         con->rx_action = accept_from_sock;
1173         con->connect_action = tcp_connect_to_sock;
1174         write_unlock_bh(&sock->sk->sk_callback_lock);
1175
1176         /* Bind to our port */
1177         make_sockaddr(saddr, dlm_config.ci_tcp_port, &addr_len);
1178         result = sock->ops->bind(sock, (struct sockaddr *) saddr, addr_len);
1179         if (result < 0) {
1180                 log_print("Can't bind to port %d", dlm_config.ci_tcp_port);
1181                 sock_release(sock);
1182                 sock = NULL;
1183                 con->sock = NULL;
1184                 goto create_out;
1185         }
1186         sock_set_keepalive(sock->sk);
1187
1188         result = sock->ops->listen(sock, 5);
1189         if (result < 0) {
1190                 log_print("Can't listen on port %d", dlm_config.ci_tcp_port);
1191                 sock_release(sock);
1192                 sock = NULL;
1193                 goto create_out;
1194         }
1195
1196 create_out:
1197         return sock;
1198 }
1199
1200 /* Get local addresses */
1201 static void init_local(void)
1202 {
1203         struct sockaddr_storage sas, *addr;
1204         int i;
1205
1206         dlm_local_count = 0;
1207         for (i = 0; i < DLM_MAX_ADDR_COUNT; i++) {
1208                 if (dlm_our_addr(&sas, i))
1209                         break;
1210
1211                 addr = kmemdup(&sas, sizeof(*addr), GFP_NOFS);
1212                 if (!addr)
1213                         break;
1214                 dlm_local_addr[dlm_local_count++] = addr;
1215         }
1216 }
1217
1218 static void deinit_local(void)
1219 {
1220         int i;
1221
1222         for (i = 0; i < dlm_local_count; i++)
1223                 kfree(dlm_local_addr[i]);
1224 }
1225
1226 /* Initialise SCTP socket and bind to all interfaces */
1227 static int sctp_listen_for_all(void)
1228 {
1229         struct socket *sock = NULL;
1230         int result = -EINVAL;
1231         struct connection *con = nodeid2con(0, GFP_NOFS);
1232
1233         if (!con)
1234                 return -ENOMEM;
1235
1236         log_print("Using SCTP for communications");
1237
1238         result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
1239                                   SOCK_STREAM, IPPROTO_SCTP, &sock);
1240         if (result < 0) {
1241                 log_print("Can't create comms socket, check SCTP is loaded");
1242                 goto out;
1243         }
1244
1245         sock_set_rcvbuf(sock->sk, NEEDED_RMEM);
1246         sock_set_mark(sock->sk, dlm_config.ci_mark);
1247         sctp_sock_set_nodelay(sock->sk);
1248
1249         write_lock_bh(&sock->sk->sk_callback_lock);
1250         /* Init con struct */
1251         sock->sk->sk_user_data = con;
1252         save_listen_callbacks(sock);
1253         con->sock = sock;
1254         con->sock->sk->sk_data_ready = lowcomms_data_ready;
1255         con->rx_action = accept_from_sock;
1256         con->connect_action = sctp_connect_to_sock;
1257
1258         write_unlock_bh(&sock->sk->sk_callback_lock);
1259
1260         /* Bind to all addresses. */
1261         if (sctp_bind_addrs(con, dlm_config.ci_tcp_port))
1262                 goto create_delsock;
1263
1264         result = sock->ops->listen(sock, 5);
1265         if (result < 0) {
1266                 log_print("Can't set socket listening");
1267                 goto create_delsock;
1268         }
1269
1270         return 0;
1271
1272 create_delsock:
1273         sock_release(sock);
1274         con->sock = NULL;
1275 out:
1276         return result;
1277 }
1278
1279 static int tcp_listen_for_all(void)
1280 {
1281         struct socket *sock = NULL;
1282         struct connection *con = nodeid2con(0, GFP_NOFS);
1283         int result = -EINVAL;
1284
1285         if (!con)
1286                 return -ENOMEM;
1287
1288         /* We don't support multi-homed hosts */
1289         if (dlm_local_addr[1] != NULL) {
1290                 log_print("TCP protocol can't handle multi-homed hosts, "
1291                           "try SCTP");
1292                 return -EINVAL;
1293         }
1294
1295         log_print("Using TCP for communications");
1296
1297         sock = tcp_create_listen_sock(con, dlm_local_addr[0]);
1298         if (sock) {
1299                 add_sock(sock, con);
1300                 result = 0;
1301         }
1302         else {
1303                 result = -EADDRINUSE;
1304         }
1305
1306         return result;
1307 }
1308
1309
1310
1311 static struct writequeue_entry *new_writequeue_entry(struct connection *con,
1312                                                      gfp_t allocation)
1313 {
1314         struct writequeue_entry *entry;
1315
1316         entry = kmalloc(sizeof(struct writequeue_entry), allocation);
1317         if (!entry)
1318                 return NULL;
1319
1320         entry->page = alloc_page(allocation);
1321         if (!entry->page) {
1322                 kfree(entry);
1323                 return NULL;
1324         }
1325
1326         entry->offset = 0;
1327         entry->len = 0;
1328         entry->end = 0;
1329         entry->users = 0;
1330         entry->con = con;
1331
1332         return entry;
1333 }
1334
1335 void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
1336 {
1337         struct connection *con;
1338         struct writequeue_entry *e;
1339         int offset = 0;
1340
1341         con = nodeid2con(nodeid, allocation);
1342         if (!con)
1343                 return NULL;
1344
1345         spin_lock(&con->writequeue_lock);
1346         e = list_entry(con->writequeue.prev, struct writequeue_entry, list);
1347         if ((&e->list == &con->writequeue) ||
1348             (PAGE_SIZE - e->end < len)) {
1349                 e = NULL;
1350         } else {
1351                 offset = e->end;
1352                 e->end += len;
1353                 e->users++;
1354         }
1355         spin_unlock(&con->writequeue_lock);
1356
1357         if (e) {
1358         got_one:
1359                 *ppc = page_address(e->page) + offset;
1360                 return e;
1361         }
1362
1363         e = new_writequeue_entry(con, allocation);
1364         if (e) {
1365                 spin_lock(&con->writequeue_lock);
1366                 offset = e->end;
1367                 e->end += len;
1368                 e->users++;
1369                 list_add_tail(&e->list, &con->writequeue);
1370                 spin_unlock(&con->writequeue_lock);
1371                 goto got_one;
1372         }
1373         return NULL;
1374 }
1375
1376 void dlm_lowcomms_commit_buffer(void *mh)
1377 {
1378         struct writequeue_entry *e = (struct writequeue_entry *)mh;
1379         struct connection *con = e->con;
1380         int users;
1381
1382         spin_lock(&con->writequeue_lock);
1383         users = --e->users;
1384         if (users)
1385                 goto out;
1386         e->len = e->end - e->offset;
1387         spin_unlock(&con->writequeue_lock);
1388
1389         queue_work(send_workqueue, &con->swork);
1390         return;
1391
1392 out:
1393         spin_unlock(&con->writequeue_lock);
1394         return;
1395 }
1396
1397 /* Send a message */
1398 static void send_to_sock(struct connection *con)
1399 {
1400         int ret = 0;
1401         const int msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL;
1402         struct writequeue_entry *e;
1403         int len, offset;
1404         int count = 0;
1405
1406         mutex_lock(&con->sock_mutex);
1407         if (con->sock == NULL)
1408                 goto out_connect;
1409
1410         spin_lock(&con->writequeue_lock);
1411         for (;;) {
1412                 e = list_entry(con->writequeue.next, struct writequeue_entry,
1413                                list);
1414                 if ((struct list_head *) e == &con->writequeue)
1415                         break;
1416
1417                 len = e->len;
1418                 offset = e->offset;
1419                 BUG_ON(len == 0 && e->users == 0);
1420                 spin_unlock(&con->writequeue_lock);
1421
1422                 ret = 0;
1423                 if (len) {
1424                         ret = kernel_sendpage(con->sock, e->page, offset, len,
1425                                               msg_flags);
1426                         if (ret == -EAGAIN || ret == 0) {
1427                                 if (ret == -EAGAIN &&
1428                                     test_bit(SOCKWQ_ASYNC_NOSPACE, &con->sock->flags) &&
1429                                     !test_and_set_bit(CF_APP_LIMITED, &con->flags)) {
1430                                         /* Notify TCP that we're limited by the
1431                                          * application window size.
1432                                          */
1433                                         set_bit(SOCK_NOSPACE, &con->sock->flags);
1434                                         con->sock->sk->sk_write_pending++;
1435                                 }
1436                                 cond_resched();
1437                                 goto out;
1438                         } else if (ret < 0)
1439                                 goto send_error;
1440                 }
1441
1442                 /* Don't starve people filling buffers */
1443                 if (++count >= MAX_SEND_MSG_COUNT) {
1444                         cond_resched();
1445                         count = 0;
1446                 }
1447
1448                 spin_lock(&con->writequeue_lock);
1449                 writequeue_entry_complete(e, ret);
1450         }
1451         spin_unlock(&con->writequeue_lock);
1452 out:
1453         mutex_unlock(&con->sock_mutex);
1454         return;
1455
1456 send_error:
1457         mutex_unlock(&con->sock_mutex);
1458         close_connection(con, false, false, true);
1459         /* Requeue the send work. When the work daemon runs again, it will try
1460            a new connection, then call this function again. */
1461         queue_work(send_workqueue, &con->swork);
1462         return;
1463
1464 out_connect:
1465         mutex_unlock(&con->sock_mutex);
1466         queue_work(send_workqueue, &con->swork);
1467         cond_resched();
1468 }
1469
1470 static void clean_one_writequeue(struct connection *con)
1471 {
1472         struct writequeue_entry *e, *safe;
1473
1474         spin_lock(&con->writequeue_lock);
1475         list_for_each_entry_safe(e, safe, &con->writequeue, list) {
1476                 list_del(&e->list);
1477                 free_entry(e);
1478         }
1479         spin_unlock(&con->writequeue_lock);
1480 }
1481
1482 /* Called from recovery when it knows that a node has
1483    left the cluster */
1484 int dlm_lowcomms_close(int nodeid)
1485 {
1486         struct connection *con;
1487         struct dlm_node_addr *na;
1488
1489         log_print("closing connection to node %d", nodeid);
1490         con = nodeid2con(nodeid, 0);
1491         if (con) {
1492                 set_bit(CF_CLOSE, &con->flags);
1493                 close_connection(con, true, true, true);
1494                 clean_one_writequeue(con);
1495         }
1496
1497         spin_lock(&dlm_node_addrs_spin);
1498         na = find_node_addr(nodeid);
1499         if (na) {
1500                 list_del(&na->list);
1501                 while (na->addr_count--)
1502                         kfree(na->addr[na->addr_count]);
1503                 kfree(na);
1504         }
1505         spin_unlock(&dlm_node_addrs_spin);
1506
1507         return 0;
1508 }
1509
1510 /* Receive workqueue function */
1511 static void process_recv_sockets(struct work_struct *work)
1512 {
1513         struct connection *con = container_of(work, struct connection, rwork);
1514         int err;
1515
1516         clear_bit(CF_READ_PENDING, &con->flags);
1517         do {
1518                 err = con->rx_action(con);
1519         } while (!err);
1520 }
1521
1522 /* Send workqueue function */
1523 static void process_send_sockets(struct work_struct *work)
1524 {
1525         struct connection *con = container_of(work, struct connection, swork);
1526
1527         clear_bit(CF_WRITE_PENDING, &con->flags);
1528         if (con->sock == NULL) /* not mutex protected so check it inside too */
1529                 con->connect_action(con);
1530         if (!list_empty(&con->writequeue))
1531                 send_to_sock(con);
1532 }
1533
1534 static void work_stop(void)
1535 {
1536         if (recv_workqueue)
1537                 destroy_workqueue(recv_workqueue);
1538         if (send_workqueue)
1539                 destroy_workqueue(send_workqueue);
1540 }
1541
1542 static int work_start(void)
1543 {
1544         recv_workqueue = alloc_workqueue("dlm_recv",
1545                                          WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
1546         if (!recv_workqueue) {
1547                 log_print("can't start dlm_recv");
1548                 return -ENOMEM;
1549         }
1550
1551         send_workqueue = alloc_workqueue("dlm_send",
1552                                          WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
1553         if (!send_workqueue) {
1554                 log_print("can't start dlm_send");
1555                 destroy_workqueue(recv_workqueue);
1556                 return -ENOMEM;
1557         }
1558
1559         return 0;
1560 }
1561
1562 static void _stop_conn(struct connection *con, bool and_other)
1563 {
1564         mutex_lock(&con->sock_mutex);
1565         set_bit(CF_CLOSE, &con->flags);
1566         set_bit(CF_READ_PENDING, &con->flags);
1567         set_bit(CF_WRITE_PENDING, &con->flags);
1568         if (con->sock && con->sock->sk) {
1569                 write_lock_bh(&con->sock->sk->sk_callback_lock);
1570                 con->sock->sk->sk_user_data = NULL;
1571                 write_unlock_bh(&con->sock->sk->sk_callback_lock);
1572         }
1573         if (con->othercon && and_other)
1574                 _stop_conn(con->othercon, false);
1575         mutex_unlock(&con->sock_mutex);
1576 }
1577
1578 static void stop_conn(struct connection *con)
1579 {
1580         _stop_conn(con, true);
1581 }
1582
1583 static void shutdown_conn(struct connection *con)
1584 {
1585         if (con->shutdown_action)
1586                 con->shutdown_action(con);
1587 }
1588
1589 static void connection_release(struct rcu_head *rcu)
1590 {
1591         struct connection *con = container_of(rcu, struct connection, rcu);
1592
1593         kfree(con->rx_buf);
1594         kfree(con);
1595 }
1596
1597 static void free_conn(struct connection *con)
1598 {
1599         close_connection(con, true, true, true);
1600         spin_lock(&connections_lock);
1601         hlist_del_rcu(&con->list);
1602         spin_unlock(&connections_lock);
1603         if (con->othercon) {
1604                 clean_one_writequeue(con->othercon);
1605                 call_rcu(&con->othercon->rcu, connection_release);
1606         }
1607         clean_one_writequeue(con);
1608         call_rcu(&con->rcu, connection_release);
1609 }
1610
1611 static void work_flush(void)
1612 {
1613         int ok, idx;
1614         int i;
1615         struct connection *con;
1616
1617         do {
1618                 ok = 1;
1619                 foreach_conn(stop_conn);
1620                 if (recv_workqueue)
1621                         flush_workqueue(recv_workqueue);
1622                 if (send_workqueue)
1623                         flush_workqueue(send_workqueue);
1624                 idx = srcu_read_lock(&connections_srcu);
1625                 for (i = 0; i < CONN_HASH_SIZE && ok; i++) {
1626                         hlist_for_each_entry_rcu(con, &connection_hash[i],
1627                                                  list) {
1628                                 ok &= test_bit(CF_READ_PENDING, &con->flags);
1629                                 ok &= test_bit(CF_WRITE_PENDING, &con->flags);
1630                                 if (con->othercon) {
1631                                         ok &= test_bit(CF_READ_PENDING,
1632                                                        &con->othercon->flags);
1633                                         ok &= test_bit(CF_WRITE_PENDING,
1634                                                        &con->othercon->flags);
1635                                 }
1636                         }
1637                 }
1638                 srcu_read_unlock(&connections_srcu, idx);
1639         } while (!ok);
1640 }
1641
1642 void dlm_lowcomms_stop(void)
1643 {
1644         /* Set all the flags to prevent any
1645            socket activity.
1646         */
1647         dlm_allow_conn = 0;
1648
1649         if (recv_workqueue)
1650                 flush_workqueue(recv_workqueue);
1651         if (send_workqueue)
1652                 flush_workqueue(send_workqueue);
1653
1654         foreach_conn(shutdown_conn);
1655         work_flush();
1656         foreach_conn(free_conn);
1657         work_stop();
1658         deinit_local();
1659 }
1660
1661 int dlm_lowcomms_start(void)
1662 {
1663         int error = -EINVAL;
1664         struct connection *con;
1665         int i;
1666
1667         for (i = 0; i < CONN_HASH_SIZE; i++)
1668                 INIT_HLIST_HEAD(&connection_hash[i]);
1669
1670         init_local();
1671         if (!dlm_local_count) {
1672                 error = -ENOTCONN;
1673                 log_print("no local IP address has been set");
1674                 goto fail;
1675         }
1676
1677         error = work_start();
1678         if (error)
1679                 goto fail;
1680
1681         dlm_allow_conn = 1;
1682
1683         /* Start listening */
1684         if (dlm_config.ci_protocol == 0)
1685                 error = tcp_listen_for_all();
1686         else
1687                 error = sctp_listen_for_all();
1688         if (error)
1689                 goto fail_unlisten;
1690
1691         return 0;
1692
1693 fail_unlisten:
1694         dlm_allow_conn = 0;
1695         con = nodeid2con(0,0);
1696         if (con)
1697                 free_conn(con);
1698 fail:
1699         return error;
1700 }
1701
1702 void dlm_lowcomms_exit(void)
1703 {
1704         struct dlm_node_addr *na, *safe;
1705
1706         spin_lock(&dlm_node_addrs_spin);
1707         list_for_each_entry_safe(na, safe, &dlm_node_addrs, list) {
1708                 list_del(&na->list);
1709                 while (na->addr_count--)
1710                         kfree(na->addr[na->addr_count]);
1711                 kfree(na);
1712         }
1713         spin_unlock(&dlm_node_addrs_spin);
1714 }