fs/dlm/midcomms.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) 2004-2021 Red Hat, Inc.  All rights reserved.
   7 **
   8 **
   9 *******************************************************************************
  10 ******************************************************************************/
  11
  12 /*
  13  * midcomms.c
  14  *
  15  * This is the appallingly named "mid-level" comms layer. It takes care about
  16  * deliver an on application layer "reliable" communication above the used
  17  * lowcomms transport layer.
  18  *
  19  * How it works:
  20  *
  21  * Each nodes keeps track of all send DLM messages in send_queue with a sequence
  22  * number. The receive will send an DLM_ACK message back for every DLM message
  23  * received at the other side. If a reconnect happens in lowcomms we will send
  24  * all unacknowledged dlm messages again. The receiving side might drop any already
  25  * received message by comparing sequence numbers.
  26  *
  27  * How version detection works:
  28  *
  29  * Due the fact that dlm has pre-configured node addresses on every side
  30  * it is in it's nature that every side connects at starts to transmit
  31  * dlm messages which ends in a race. However DLM_RCOM_NAMES, DLM_RCOM_STATUS
  32  * and their replies are the first messages which are exchanges. Due backwards
  33  * compatibility these messages are not covered by the midcomms re-transmission
  34  * layer. These messages have their own re-transmission handling in the dlm
  35  * application layer. The version field of every node will be set on these RCOM
  36  * messages as soon as they arrived and the node isn't yet part of the nodes
  37  * hash. There exists also logic to detect version mismatched if something weird
  38  * going on or the first messages isn't an expected one.
  39  *
  40  * Termination:
  41  *
  42  * The midcomms layer does a 4 way handshake for termination on DLM protocol
  43  * like TCP supports it with half-closed socket support. SCTP doesn't support
  44  * half-closed socket, so we do it on DLM layer. Also socket shutdown() can be
  45  * interrupted by .e.g. tcp reset itself. Additional there exists the othercon
  46  * paradigm in lowcomms which cannot be easily without breaking backwards
  47  * compatibility. A node cannot send anything to another node when a DLM_FIN
  48  * message was send. There exists additional logic to print a warning if
  49  * DLM wants to do it. There exists a state handling like RFC 793 but reduced
  50  * to termination only. The event "member removal event" describes the cluster
  51  * manager removed the node from internal lists, at this point DLM does not
  52  * send any message to the other node. There exists two cases:
  53  *
  54  * 1. The cluster member was removed and we received a FIN
  55  * OR
  56  * 2. We received a FIN but the member was not removed yet
  57  *
  58  * One of these cases will do the CLOSE_WAIT to LAST_ACK change.
  59  *
  60  *
  61  *                              +---------+
  62  *                              | CLOSED  |
  63  *                              +---------+
  64  *                                   | add member/receive RCOM version
  65  *                                   |            detection msg
  66  *                                   V
  67  *                              +---------+
  68  *                              |  ESTAB  |
  69  *                              +---------+
  70  *                       CLOSE    |     |    rcv FIN
  71  *                      -------   |     |    -------
  72  * +---------+          snd FIN  /       \   snd ACK          +---------+
  73  * |  FIN    |<-----------------           ------------------>|  CLOSE  |
  74  * | WAIT-1  |------------------                              |   WAIT  |
  75  * +---------+          rcv FIN  \                            +---------+
  76  * | rcv ACK of FIN   -------   |                            CLOSE  | member
  77  * | --------------   snd ACK   |                           ------- | removal
  78  * V        x                   V                           snd FIN V event
  79  * +---------+                  +---------+                   +---------+
  80  * |FINWAIT-2|                  | CLOSING |                   | LAST-ACK|
  81  * +---------+                  +---------+                   +---------+
  82  * |                rcv ACK of FIN |                 rcv ACK of FIN |
  83  * |  rcv FIN       -------------- |                 -------------- |
  84  * |  -------              x       V                        x       V
  85  *  \ snd ACK                 +---------+                   +---------+
  86  *   ------------------------>| CLOSED  |                   | CLOSED  |
  87  *                            +---------+                   +---------+
  88  *
  89  * NOTE: any state can interrupted by midcomms_close() and state will be
  90  * switched to CLOSED in case of fencing. There exists also some timeout
  91  * handling when we receive the version detection RCOM messages which is
  92  * made by observation.
  93  *
  94  * Future improvements:
  95  *
  96  * There exists some known issues/improvements of the dlm handling. Some
  97  * of them should be done in a next major dlm version bump which makes
  98  * it incompatible with previous versions.
  99  *
 100  * Unaligned memory access:
 101  *
 102  * There exists cases when the dlm message buffer length is not aligned
 103  * to 8 byte. However seems nobody detected any problem with it. This
 104  * can be fixed in the next major version bump of dlm.
 105  *
 106  * Version detection:
 107  *
 108  * The version detection and how it's done is related to backwards
 109  * compatibility. There exists better ways to make a better handling.
 110  * However this should be changed in the next major version bump of dlm.
 111  *
 112  * Tail Size checking:
 113  *
 114  * There exists a message tail payload in e.g. DLM_MSG however we don't
 115  * check it against the message length yet regarding to the receive buffer
 116  * length. That need to be validated.
 117  *
 118  * Fencing bad nodes:
 119  *
 120  * At timeout places or weird sequence number behaviours we should send
 121  * a fencing request to the cluster manager.
 122  */
 123
 124 /* Debug switch to enable a 5 seconds sleep waiting of a termination.
 125  * This can be useful to test fencing while termination is running.
 126  * This requires a setup with only gfs2 as dlm user, so that the
 127  * last umount will terminate the connection.
 128  *
 129  * However it became useful to test, while the 5 seconds block in umount
 130  * just press the reset button. In a lot of dropping the termination
 131  * process can could take several seconds.
 132  */
 133 #define DLM_DEBUG_FENCE_TERMINATION     0
 134
 135 #include <trace/events/dlm.h>
 136 #include <net/tcp.h>
 137
 138 #include "dlm_internal.h"
 139 #include "lowcomms.h"
 140 #include "config.h"
 141 #include "memory.h"
 142 #include "lock.h"
 143 #include "util.h"
 144 #include "midcomms.h"
 145
 146 /* init value for sequence numbers for testing purpose only e.g. overflows */
 147 #define DLM_SEQ_INIT            0
 148 /* 5 seconds wait to sync ending of dlm */
 149 #define DLM_SHUTDOWN_TIMEOUT    msecs_to_jiffies(5000)
 150 #define DLM_VERSION_NOT_SET     0
 151 #define DLM_SEND_ACK_BACK_MSG_THRESHOLD 32
 152 #define DLM_RECV_ACK_BACK_MSG_THRESHOLD (DLM_SEND_ACK_BACK_MSG_THRESHOLD * 8)
 153
 154 struct midcomms_node {
 155         int nodeid;
 156         uint32_t version;
 157         atomic_t seq_send;
 158         atomic_t seq_next;
 159         /* These queues are unbound because we cannot drop any message in dlm.
 160          * We could send a fence signal for a specific node to the cluster
 161          * manager if queues hits some maximum value, however this handling
 162          * not supported yet.
 163          */
 164         struct list_head send_queue;
 165         spinlock_t send_queue_lock;
 166         atomic_t send_queue_cnt;
 167 #define DLM_NODE_FLAG_CLOSE     1
 168 #define DLM_NODE_FLAG_STOP_TX   2
 169 #define DLM_NODE_FLAG_STOP_RX   3
 170         atomic_t ulp_delivered;
 171         unsigned long flags;
 172         wait_queue_head_t shutdown_wait;
 173
 174         /* dlm tcp termination state */
 175 #define DLM_CLOSED      1
 176 #define DLM_ESTABLISHED 2
 177 #define DLM_FIN_WAIT1   3
 178 #define DLM_FIN_WAIT2   4
 179 #define DLM_CLOSE_WAIT  5
 180 #define DLM_LAST_ACK    6
 181 #define DLM_CLOSING     7
 182         int state;
 183         spinlock_t state_lock;
 184
 185         /* counts how many lockspaces are using this node
 186          * this refcount is necessary to determine if the
 187          * node wants to disconnect.
 188          */
 189         int users;
 190
 191         /* not protected by srcu, node_hash lifetime */
 192         void *debugfs;
 193
 194         struct hlist_node hlist;
 195         struct rcu_head rcu;
 196 };
 197
 198 struct dlm_mhandle {
 199         const union dlm_packet *inner_p;
 200         struct midcomms_node *node;
 201         struct dlm_opts *opts;
 202         struct dlm_msg *msg;
 203         bool committed;
 204         uint32_t seq;
 205
 206         void (*ack_rcv)(struct midcomms_node *node);
 207
 208         /* get_mhandle/commit srcu idx exchange */
 209         int idx;
 210
 211         struct list_head list;
 212         struct rcu_head rcu;
 213 };
 214
 215 static struct hlist_head node_hash[CONN_HASH_SIZE];
 216 static DEFINE_SPINLOCK(nodes_lock);
 217 DEFINE_STATIC_SRCU(nodes_srcu);
 218
 219 /* This mutex prevents that midcomms_close() is running while
 220  * stop() or remove(). As I experienced invalid memory access
 221  * behaviours when DLM_DEBUG_FENCE_TERMINATION is enabled and
 222  * resetting machines. I will end in some double deletion in nodes
 223  * datastructure.
 224  */
 225 static DEFINE_MUTEX(close_lock);
 226
 227 struct kmem_cache *dlm_midcomms_cache_create(void)
 228 {
 229         return kmem_cache_create("dlm_mhandle", sizeof(struct dlm_mhandle),
 230                                  0, 0, NULL);
 231 }
 232
 233 static inline const char *dlm_state_str(int state)
 234 {
 235         switch (state) {
 236         case DLM_CLOSED:
 237                 return "CLOSED";
 238         case DLM_ESTABLISHED:
 239                 return "ESTABLISHED";
 240         case DLM_FIN_WAIT1:
 241                 return "FIN_WAIT1";
 242         case DLM_FIN_WAIT2:
 243                 return "FIN_WAIT2";
 244         case DLM_CLOSE_WAIT:
 245                 return "CLOSE_WAIT";
 246         case DLM_LAST_ACK:
 247                 return "LAST_ACK";
 248         case DLM_CLOSING:
 249                 return "CLOSING";
 250         default:
 251                 return "UNKNOWN";
 252         }
 253 }
 254
 255 const char *dlm_midcomms_state(struct midcomms_node *node)
 256 {
 257         return dlm_state_str(node->state);
 258 }
 259
 260 unsigned long dlm_midcomms_flags(struct midcomms_node *node)
 261 {
 262         return node->flags;
 263 }
 264
 265 int dlm_midcomms_send_queue_cnt(struct midcomms_node *node)
 266 {
 267         return atomic_read(&node->send_queue_cnt);
 268 }
 269
 270 uint32_t dlm_midcomms_version(struct midcomms_node *node)
 271 {
 272         return node->version;
 273 }
 274
 275 static struct midcomms_node *__find_node(int nodeid, int r)
 276 {
 277         struct midcomms_node *node;
 278
 279         hlist_for_each_entry_rcu(node, &node_hash[r], hlist) {
 280                 if (node->nodeid == nodeid)
 281                         return node;
 282         }
 283
 284         return NULL;
 285 }
 286
 287 static void dlm_mhandle_release(struct rcu_head *rcu)
 288 {
 289         struct dlm_mhandle *mh = container_of(rcu, struct dlm_mhandle, rcu);
 290
 291         dlm_lowcomms_put_msg(mh->msg);
 292         dlm_free_mhandle(mh);
 293 }
 294
 295 static void dlm_mhandle_delete(struct midcomms_node *node,
 296                                struct dlm_mhandle *mh)
 297 {
 298         list_del_rcu(&mh->list);
 299         atomic_dec(&node->send_queue_cnt);
 300         call_rcu(&mh->rcu, dlm_mhandle_release);
 301 }
 302
 303 static void dlm_send_queue_flush(struct midcomms_node *node)
 304 {
 305         struct dlm_mhandle *mh;
 306
 307         pr_debug("flush midcomms send queue of node %d\n", node->nodeid);
 308
 309         rcu_read_lock();
 310         spin_lock_bh(&node->send_queue_lock);
 311         list_for_each_entry_rcu(mh, &node->send_queue, list) {
 312                 dlm_mhandle_delete(node, mh);
 313         }
 314         spin_unlock_bh(&node->send_queue_lock);
 315         rcu_read_unlock();
 316 }
 317
 318 static void midcomms_node_reset(struct midcomms_node *node)
 319 {
 320         pr_debug("reset node %d\n", node->nodeid);
 321
 322         atomic_set(&node->seq_next, DLM_SEQ_INIT);
 323         atomic_set(&node->seq_send, DLM_SEQ_INIT);
 324         atomic_set(&node->ulp_delivered, 0);
 325         node->version = DLM_VERSION_NOT_SET;
 326         node->flags = 0;
 327
 328         dlm_send_queue_flush(node);
 329         node->state = DLM_CLOSED;
 330         wake_up(&node->shutdown_wait);
 331 }
 332
 333 static struct midcomms_node *nodeid2node(int nodeid)
 334 {
 335         return __find_node(nodeid, nodeid_hash(nodeid));
 336 }
 337
 338 int dlm_midcomms_addr(int nodeid, struct sockaddr_storage *addr, int len)
 339 {
 340         int ret, idx, r = nodeid_hash(nodeid);
 341         struct midcomms_node *node;
 342
 343         ret = dlm_lowcomms_addr(nodeid, addr, len);
 344         if (ret)
 345                 return ret;
 346
 347         idx = srcu_read_lock(&nodes_srcu);
 348         node = __find_node(nodeid, r);
 349         if (node) {
 350                 srcu_read_unlock(&nodes_srcu, idx);
 351                 return 0;
 352         }
 353         srcu_read_unlock(&nodes_srcu, idx);
 354
 355         node = kmalloc(sizeof(*node), GFP_NOFS);
 356         if (!node)
 357                 return -ENOMEM;
 358
 359         node->nodeid = nodeid;
 360         spin_lock_init(&node->state_lock);
 361         spin_lock_init(&node->send_queue_lock);
 362         atomic_set(&node->send_queue_cnt, 0);
 363         INIT_LIST_HEAD(&node->send_queue);
 364         init_waitqueue_head(&node->shutdown_wait);
 365         node->users = 0;
 366         midcomms_node_reset(node);
 367
 368         spin_lock(&nodes_lock);
 369         hlist_add_head_rcu(&node->hlist, &node_hash[r]);
 370         spin_unlock(&nodes_lock);
 371
 372         node->debugfs = dlm_create_debug_comms_file(nodeid, node);
 373         return 0;
 374 }
 375
 376 static int dlm_send_ack(int nodeid, uint32_t seq)
 377 {
 378         int mb_len = sizeof(struct dlm_header);
 379         struct dlm_header *m_header;
 380         struct dlm_msg *msg;
 381         char *ppc;
 382
 383         msg = dlm_lowcomms_new_msg(nodeid, mb_len, GFP_ATOMIC, &ppc,
 384                                    NULL, NULL);
 385         if (!msg)
 386                 return -ENOMEM;
 387
 388         m_header = (struct dlm_header *)ppc;
 389
 390         m_header->h_version = cpu_to_le32(DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
 391         m_header->h_nodeid = cpu_to_le32(dlm_our_nodeid());
 392         m_header->h_length = cpu_to_le16(mb_len);
 393         m_header->h_cmd = DLM_ACK;
 394         m_header->u.h_seq = cpu_to_le32(seq);
 395
 396         dlm_lowcomms_commit_msg(msg);
 397         dlm_lowcomms_put_msg(msg);
 398
 399         return 0;
 400 }
 401
 402 static void dlm_send_ack_threshold(struct midcomms_node *node,
 403                                    uint32_t threshold)
 404 {
 405         uint32_t oval, nval;
 406         bool send_ack;
 407
 408         /* let only send one user trigger threshold to send ack back */
 409         do {
 410                 oval = atomic_read(&node->ulp_delivered);
 411                 send_ack = (oval > threshold);
 412                 /* abort if threshold is not reached */
 413                 if (!send_ack)
 414                         break;
 415
 416                 nval = 0;
 417                 /* try to reset ulp_delivered counter */
 418         } while (atomic_cmpxchg(&node->ulp_delivered, oval, nval) != oval);
 419
 420         if (send_ack)
 421                 dlm_send_ack(node->nodeid, atomic_read(&node->seq_next));
 422 }
 423
 424 static int dlm_send_fin(struct midcomms_node *node,
 425                         void (*ack_rcv)(struct midcomms_node *node))
 426 {
 427         int mb_len = sizeof(struct dlm_header);
 428         struct dlm_header *m_header;
 429         struct dlm_mhandle *mh;
 430         char *ppc;
 431
 432         mh = dlm_midcomms_get_mhandle(node->nodeid, mb_len, GFP_ATOMIC, &ppc);
 433         if (!mh)
 434                 return -ENOMEM;
 435
 436         set_bit(DLM_NODE_FLAG_STOP_TX, &node->flags);
 437         mh->ack_rcv = ack_rcv;
 438
 439         m_header = (struct dlm_header *)ppc;
 440
 441         m_header->h_version = cpu_to_le32(DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
 442         m_header->h_nodeid = cpu_to_le32(dlm_our_nodeid());
 443         m_header->h_length = cpu_to_le16(mb_len);
 444         m_header->h_cmd = DLM_FIN;
 445
 446         pr_debug("sending fin msg to node %d\n", node->nodeid);
 447         dlm_midcomms_commit_mhandle(mh, NULL, 0);
 448
 449         return 0;
 450 }
 451
 452 static void dlm_receive_ack(struct midcomms_node *node, uint32_t seq)
 453 {
 454         struct dlm_mhandle *mh;
 455
 456         rcu_read_lock();
 457         list_for_each_entry_rcu(mh, &node->send_queue, list) {
 458                 if (before(mh->seq, seq)) {
 459                         if (mh->ack_rcv)
 460                                 mh->ack_rcv(node);
 461                 } else {
 462                         /* send queue should be ordered */
 463                         break;
 464                 }
 465         }
 466
 467         spin_lock_bh(&node->send_queue_lock);
 468         list_for_each_entry_rcu(mh, &node->send_queue, list) {
 469                 if (before(mh->seq, seq)) {
 470                         dlm_mhandle_delete(node, mh);
 471                 } else {
 472                         /* send queue should be ordered */
 473                         break;
 474                 }
 475         }
 476         spin_unlock_bh(&node->send_queue_lock);
 477         rcu_read_unlock();
 478 }
 479
 480 static void dlm_pas_fin_ack_rcv(struct midcomms_node *node)
 481 {
 482         spin_lock(&node->state_lock);
 483         pr_debug("receive passive fin ack from node %d with state %s\n",
 484                  node->nodeid, dlm_state_str(node->state));
 485
 486         switch (node->state) {
 487         case DLM_LAST_ACK:
 488                 /* DLM_CLOSED */
 489                 midcomms_node_reset(node);
 490                 break;
 491         case DLM_CLOSED:
 492                 /* not valid but somehow we got what we want */
 493                 wake_up(&node->shutdown_wait);
 494                 break;
 495         default:
 496                 spin_unlock(&node->state_lock);
 497                 log_print("%s: unexpected state: %d",
 498                           __func__, node->state);
 499                 WARN_ON_ONCE(1);
 500                 return;
 501         }
 502         spin_unlock(&node->state_lock);
 503 }
 504
 505 static void dlm_receive_buffer_3_2_trace(uint32_t seq,
 506                                          const union dlm_packet *p)
 507 {
 508         switch (p->header.h_cmd) {
 509         case DLM_MSG:
 510                 trace_dlm_recv_message(dlm_our_nodeid(), seq, &p->message);
 511                 break;
 512         case DLM_RCOM:
 513                 trace_dlm_recv_rcom(dlm_our_nodeid(), seq, &p->rcom);
 514                 break;
 515         default:
 516                 break;
 517         }
 518 }
 519
 520 static void dlm_midcomms_receive_buffer(const union dlm_packet *p,
 521                                         struct midcomms_node *node,
 522                                         uint32_t seq)
 523 {
 524         bool is_expected_seq;
 525         uint32_t oval, nval;
 526
 527         do {
 528                 oval = atomic_read(&node->seq_next);
 529                 is_expected_seq = (oval == seq);
 530                 if (!is_expected_seq)
 531                         break;
 532
 533                 nval = oval + 1;
 534         } while (atomic_cmpxchg(&node->seq_next, oval, nval) != oval);
 535
 536         if (is_expected_seq) {
 537                 switch (p->header.h_cmd) {
 538                 case DLM_FIN:
 539                         spin_lock(&node->state_lock);
 540                         pr_debug("receive fin msg from node %d with state %s\n",
 541                                  node->nodeid, dlm_state_str(node->state));
 542
 543                         switch (node->state) {
 544                         case DLM_ESTABLISHED:
 545                                 dlm_send_ack(node->nodeid, nval);
 546
 547                                 /* passive shutdown DLM_LAST_ACK case 1
 548                                  * additional we check if the node is used by
 549                                  * cluster manager events at all.
 550                                  */
 551                                 if (node->users == 0) {
 552                                         node->state = DLM_LAST_ACK;
 553                                         pr_debug("switch node %d to state %s case 1\n",
 554                                                  node->nodeid, dlm_state_str(node->state));
 555                                         set_bit(DLM_NODE_FLAG_STOP_RX, &node->flags);
 556                                         dlm_send_fin(node, dlm_pas_fin_ack_rcv);
 557                                 } else {
 558                                         node->state = DLM_CLOSE_WAIT;
 559                                         pr_debug("switch node %d to state %s\n",
 560                                                  node->nodeid, dlm_state_str(node->state));
 561                                 }
 562                                 break;
 563                         case DLM_FIN_WAIT1:
 564                                 dlm_send_ack(node->nodeid, nval);
 565                                 node->state = DLM_CLOSING;
 566                                 set_bit(DLM_NODE_FLAG_STOP_RX, &node->flags);
 567                                 pr_debug("switch node %d to state %s\n",
 568                                          node->nodeid, dlm_state_str(node->state));
 569                                 break;
 570                         case DLM_FIN_WAIT2:
 571                                 dlm_send_ack(node->nodeid, nval);
 572                                 midcomms_node_reset(node);
 573                                 pr_debug("switch node %d to state %s\n",
 574                                          node->nodeid, dlm_state_str(node->state));
 575                                 break;
 576                         case DLM_LAST_ACK:
 577                                 /* probably remove_member caught it, do nothing */
 578                                 break;
 579                         default:
 580                                 spin_unlock(&node->state_lock);
 581                                 log_print("%s: unexpected state: %d",
 582                                           __func__, node->state);
 583                                 WARN_ON_ONCE(1);
 584                                 return;
 585                         }
 586                         spin_unlock(&node->state_lock);
 587                         break;
 588                 default:
 589                         WARN_ON_ONCE(test_bit(DLM_NODE_FLAG_STOP_RX, &node->flags));
 590                         dlm_receive_buffer_3_2_trace(seq, p);
 591                         dlm_receive_buffer(p, node->nodeid);
 592                         atomic_inc(&node->ulp_delivered);
 593                         /* unlikely case to send ack back when we don't transmit */
 594                         dlm_send_ack_threshold(node, DLM_RECV_ACK_BACK_MSG_THRESHOLD);
 595                         break;
 596                 }
 597         } else {
 598                 /* retry to ack message which we already have by sending back
 599                  * current node->seq_next number as ack.
 600                  */
 601                 if (seq < oval)
 602                         dlm_send_ack(node->nodeid, oval);
 603
 604                 log_print_ratelimited("ignore dlm msg because seq mismatch, seq: %u, expected: %u, nodeid: %d",
 605                                       seq, oval, node->nodeid);
 606         }
 607 }
 608
 609 static int dlm_opts_check_msglen(const union dlm_packet *p, uint16_t msglen,
 610                                  int nodeid)
 611 {
 612         int len = msglen;
 613
 614         /* we only trust outer header msglen because
 615          * it's checked against receive buffer length.
 616          */
 617         if (len < sizeof(struct dlm_opts))
 618                 return -1;
 619         len -= sizeof(struct dlm_opts);
 620
 621         if (len < le16_to_cpu(p->opts.o_optlen))
 622                 return -1;
 623         len -= le16_to_cpu(p->opts.o_optlen);
 624
 625         switch (p->opts.o_nextcmd) {
 626         case DLM_FIN:
 627                 if (len < sizeof(struct dlm_header)) {
 628                         log_print("fin too small: %d, will skip this message from node %d",
 629                                   len, nodeid);
 630                         return -1;
 631                 }
 632
 633                 break;
 634         case DLM_MSG:
 635                 if (len < sizeof(struct dlm_message)) {
 636                         log_print("msg too small: %d, will skip this message from node %d",
 637                                   msglen, nodeid);
 638                         return -1;
 639                 }
 640
 641                 break;
 642         case DLM_RCOM:
 643                 if (len < sizeof(struct dlm_rcom)) {
 644                         log_print("rcom msg too small: %d, will skip this message from node %d",
 645                                   len, nodeid);
 646                         return -1;
 647                 }
 648
 649                 break;
 650         default:
 651                 log_print("unsupported o_nextcmd received: %u, will skip this message from node %d",
 652                           p->opts.o_nextcmd, nodeid);
 653                 return -1;
 654         }
 655
 656         return 0;
 657 }
 658
 659 static void dlm_midcomms_receive_buffer_3_2(const union dlm_packet *p, int nodeid)
 660 {
 661         uint16_t msglen = le16_to_cpu(p->header.h_length);
 662         struct midcomms_node *node;
 663         uint32_t seq;
 664         int ret, idx;
 665
 666         idx = srcu_read_lock(&nodes_srcu);
 667         node = nodeid2node(nodeid);
 668         if (WARN_ON_ONCE(!node))
 669                 goto out;
 670
 671         switch (node->version) {
 672         case DLM_VERSION_NOT_SET:
 673                 node->version = DLM_VERSION_3_2;
 674                 wake_up(&node->shutdown_wait);
 675                 log_print("version 0x%08x for node %d detected", DLM_VERSION_3_2,
 676                           node->nodeid);
 677
 678                 spin_lock(&node->state_lock);
 679                 switch (node->state) {
 680                 case DLM_CLOSED:
 681                         node->state = DLM_ESTABLISHED;
 682                         pr_debug("switch node %d to state %s\n",
 683                                  node->nodeid, dlm_state_str(node->state));
 684                         break;
 685                 default:
 686                         break;
 687                 }
 688                 spin_unlock(&node->state_lock);
 689
 690                 break;
 691         case DLM_VERSION_3_2:
 692                 break;
 693         default:
 694                 log_print_ratelimited("version mismatch detected, assumed 0x%08x but node %d has 0x%08x",
 695                                       DLM_VERSION_3_2, node->nodeid, node->version);
 696                 goto out;
 697         }
 698
 699         switch (p->header.h_cmd) {
 700         case DLM_RCOM:
 701                 /* these rcom message we use to determine version.
 702                  * they have their own retransmission handling and
 703                  * are the first messages of dlm.
 704                  *
 705                  * length already checked.
 706                  */
 707                 switch (p->rcom.rc_type) {
 708                 case cpu_to_le32(DLM_RCOM_NAMES):
 709                         fallthrough;
 710                 case cpu_to_le32(DLM_RCOM_NAMES_REPLY):
 711                         fallthrough;
 712                 case cpu_to_le32(DLM_RCOM_STATUS):
 713                         fallthrough;
 714                 case cpu_to_le32(DLM_RCOM_STATUS_REPLY):
 715                         break;
 716                 default:
 717                         log_print("unsupported rcom type received: %u, will skip this message from node %d",
 718                                   le32_to_cpu(p->rcom.rc_type), nodeid);
 719                         goto out;
 720                 }
 721
 722                 WARN_ON_ONCE(test_bit(DLM_NODE_FLAG_STOP_RX, &node->flags));
 723                 dlm_receive_buffer(p, nodeid);
 724                 break;
 725         case DLM_OPTS:
 726                 seq = le32_to_cpu(p->header.u.h_seq);
 727
 728                 ret = dlm_opts_check_msglen(p, msglen, nodeid);
 729                 if (ret < 0) {
 730                         log_print("opts msg too small: %u, will skip this message from node %d",
 731                                   msglen, nodeid);
 732                         goto out;
 733                 }
 734
 735                 p = (union dlm_packet *)((unsigned char *)p->opts.o_opts +
 736                                          le16_to_cpu(p->opts.o_optlen));
 737
 738                 /* recheck inner msglen just if it's not garbage */
 739                 msglen = le16_to_cpu(p->header.h_length);
 740                 switch (p->header.h_cmd) {
 741                 case DLM_RCOM:
 742                         if (msglen < sizeof(struct dlm_rcom)) {
 743                                 log_print("inner rcom msg too small: %u, will skip this message from node %d",
 744                                           msglen, nodeid);
 745                                 goto out;
 746                         }
 747
 748                         break;
 749                 case DLM_MSG:
 750                         if (msglen < sizeof(struct dlm_message)) {
 751                                 log_print("inner msg too small: %u, will skip this message from node %d",
 752                                           msglen, nodeid);
 753                                 goto out;
 754                         }
 755
 756                         break;
 757                 case DLM_FIN:
 758                         if (msglen < sizeof(struct dlm_header)) {
 759                                 log_print("inner fin too small: %u, will skip this message from node %d",
 760                                           msglen, nodeid);
 761                                 goto out;
 762                         }
 763
 764                         break;
 765                 default:
 766                         log_print("unsupported inner h_cmd received: %u, will skip this message from node %d",
 767                                   msglen, nodeid);
 768                         goto out;
 769                 }
 770
 771                 dlm_midcomms_receive_buffer(p, node, seq);
 772                 break;
 773         case DLM_ACK:
 774                 seq = le32_to_cpu(p->header.u.h_seq);
 775                 dlm_receive_ack(node, seq);
 776                 break;
 777         default:
 778                 log_print("unsupported h_cmd received: %u, will skip this message from node %d",
 779                           p->header.h_cmd, nodeid);
 780                 break;
 781         }
 782
 783 out:
 784         srcu_read_unlock(&nodes_srcu, idx);
 785 }
 786
 787 static void dlm_midcomms_receive_buffer_3_1(const union dlm_packet *p, int nodeid)
 788 {
 789         uint16_t msglen = le16_to_cpu(p->header.h_length);
 790         struct midcomms_node *node;
 791         int idx;
 792
 793         idx = srcu_read_lock(&nodes_srcu);
 794         node = nodeid2node(nodeid);
 795         if (WARN_ON_ONCE(!node)) {
 796                 srcu_read_unlock(&nodes_srcu, idx);
 797                 return;
 798         }
 799
 800         switch (node->version) {
 801         case DLM_VERSION_NOT_SET:
 802                 node->version = DLM_VERSION_3_1;
 803                 wake_up(&node->shutdown_wait);
 804                 log_print("version 0x%08x for node %d detected", DLM_VERSION_3_1,
 805                           node->nodeid);
 806                 break;
 807         case DLM_VERSION_3_1:
 808                 break;
 809         default:
 810                 log_print_ratelimited("version mismatch detected, assumed 0x%08x but node %d has 0x%08x",
 811                                       DLM_VERSION_3_1, node->nodeid, node->version);
 812                 srcu_read_unlock(&nodes_srcu, idx);
 813                 return;
 814         }
 815         srcu_read_unlock(&nodes_srcu, idx);
 816
 817         switch (p->header.h_cmd) {
 818         case DLM_RCOM:
 819                 /* length already checked */
 820                 break;
 821         case DLM_MSG:
 822                 if (msglen < sizeof(struct dlm_message)) {
 823                         log_print("msg too small: %u, will skip this message from node %d",
 824                                   msglen, nodeid);
 825                         return;
 826                 }
 827
 828                 break;
 829         default:
 830                 log_print("unsupported h_cmd received: %u, will skip this message from node %d",
 831                           p->header.h_cmd, nodeid);
 832                 return;
 833         }
 834
 835         dlm_receive_buffer(p, nodeid);
 836 }
 837
 838 int dlm_validate_incoming_buffer(int nodeid, unsigned char *buf, int len)
 839 {
 840         const unsigned char *ptr = buf;
 841         const struct dlm_header *hd;
 842         uint16_t msglen;
 843         int ret = 0;
 844
 845         while (len >= sizeof(struct dlm_header)) {
 846                 hd = (struct dlm_header *)ptr;
 847
 848                 /* no message should be more than DLM_MAX_SOCKET_BUFSIZE or
 849                  * less than dlm_header size.
 850                  *
 851                  * Some messages does not have a 8 byte length boundary yet
 852                  * which can occur in a unaligned memory access of some dlm
 853                  * messages. However this problem need to be fixed at the
 854                  * sending side, for now it seems nobody run into architecture
 855                  * related issues yet but it slows down some processing.
 856                  * Fixing this issue should be scheduled in future by doing
 857                  * the next major version bump.
 858                  */
 859                 msglen = le16_to_cpu(hd->h_length);
 860                 if (msglen > DLM_MAX_SOCKET_BUFSIZE ||
 861                     msglen < sizeof(struct dlm_header)) {
 862                         log_print("received invalid length header: %u from node %d, will abort message parsing",
 863                                   msglen, nodeid);
 864                         return -EBADMSG;
 865                 }
 866
 867                 /* caller will take care that leftover
 868                  * will be parsed next call with more data
 869                  */
 870                 if (msglen > len)
 871                         break;
 872
 873                 ret += msglen;
 874                 len -= msglen;
 875                 ptr += msglen;
 876         }
 877
 878         return ret;
 879 }
 880
 881 /*
 882  * Called from the low-level comms layer to process a buffer of
 883  * commands.
 884  */
 885 int dlm_process_incoming_buffer(int nodeid, unsigned char *buf, int len)
 886 {
 887         const unsigned char *ptr = buf;
 888         const struct dlm_header *hd;
 889         uint16_t msglen;
 890         int ret = 0;
 891
 892         while (len >= sizeof(struct dlm_header)) {
 893                 hd = (struct dlm_header *)ptr;
 894
 895                 msglen = le16_to_cpu(hd->h_length);
 896                 if (msglen > len)
 897                         break;
 898
 899                 switch (hd->h_version) {
 900                 case cpu_to_le32(DLM_VERSION_3_1):
 901                         dlm_midcomms_receive_buffer_3_1((const union dlm_packet *)ptr, nodeid);
 902                         break;
 903                 case cpu_to_le32(DLM_VERSION_3_2):
 904                         dlm_midcomms_receive_buffer_3_2((const union dlm_packet *)ptr, nodeid);
 905                         break;
 906                 default:
 907                         log_print("received invalid version header: %u from node %d, will skip this message",
 908                                   le32_to_cpu(hd->h_version), nodeid);
 909                         break;
 910                 }
 911
 912                 ret += msglen;
 913                 len -= msglen;
 914                 ptr += msglen;
 915         }
 916
 917         return ret;
 918 }
 919
 920 void dlm_midcomms_unack_msg_resend(int nodeid)
 921 {
 922         struct midcomms_node *node;
 923         struct dlm_mhandle *mh;
 924         int idx, ret;
 925
 926         idx = srcu_read_lock(&nodes_srcu);
 927         node = nodeid2node(nodeid);
 928         if (WARN_ON_ONCE(!node)) {
 929                 srcu_read_unlock(&nodes_srcu, idx);
 930                 return;
 931         }
 932
 933         /* old protocol, we don't support to retransmit on failure */
 934         switch (node->version) {
 935         case DLM_VERSION_3_2:
 936                 break;
 937         default:
 938                 srcu_read_unlock(&nodes_srcu, idx);
 939                 return;
 940         }
 941
 942         rcu_read_lock();
 943         list_for_each_entry_rcu(mh, &node->send_queue, list) {
 944                 if (!mh->committed)
 945                         continue;
 946
 947                 ret = dlm_lowcomms_resend_msg(mh->msg);
 948                 if (!ret)
 949                         log_print_ratelimited("retransmit dlm msg, seq %u, nodeid %d",
 950                                               mh->seq, node->nodeid);
 951         }
 952         rcu_read_unlock();
 953         srcu_read_unlock(&nodes_srcu, idx);
 954 }
 955
 956 static void dlm_fill_opts_header(struct dlm_opts *opts, uint16_t inner_len,
 957                                  uint32_t seq)
 958 {
 959         opts->o_header.h_cmd = DLM_OPTS;
 960         opts->o_header.h_version = cpu_to_le32(DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
 961         opts->o_header.h_nodeid = cpu_to_le32(dlm_our_nodeid());
 962         opts->o_header.h_length = cpu_to_le16(DLM_MIDCOMMS_OPT_LEN + inner_len);
 963         opts->o_header.u.h_seq = cpu_to_le32(seq);
 964 }
 965
 966 static void midcomms_new_msg_cb(void *data)
 967 {
 968         struct dlm_mhandle *mh = data;
 969
 970         atomic_inc(&mh->node->send_queue_cnt);
 971
 972         spin_lock_bh(&mh->node->send_queue_lock);
 973         list_add_tail_rcu(&mh->list, &mh->node->send_queue);
 974         spin_unlock_bh(&mh->node->send_queue_lock);
 975
 976         mh->seq = atomic_fetch_inc(&mh->node->seq_send);
 977 }
 978
 979 static struct dlm_msg *dlm_midcomms_get_msg_3_2(struct dlm_mhandle *mh, int nodeid,
 980                                                 int len, gfp_t allocation, char **ppc)
 981 {
 982         struct dlm_opts *opts;
 983         struct dlm_msg *msg;
 984
 985         msg = dlm_lowcomms_new_msg(nodeid, len + DLM_MIDCOMMS_OPT_LEN,
 986                                    allocation, ppc, midcomms_new_msg_cb, mh);
 987         if (!msg)
 988                 return NULL;
 989
 990         opts = (struct dlm_opts *)*ppc;
 991         mh->opts = opts;
 992
 993         /* add possible options here */
 994         dlm_fill_opts_header(opts, len, mh->seq);
 995
 996         *ppc += sizeof(*opts);
 997         mh->inner_p = (const union dlm_packet *)*ppc;
 998         return msg;
 999 }
1000
1001 /* avoid false positive for nodes_srcu, unlock happens in
1002  * dlm_midcomms_commit_mhandle which is a must call if success
1003  */
1004 #ifndef __CHECKER__
1005 struct dlm_mhandle *dlm_midcomms_get_mhandle(int nodeid, int len,
1006                                              gfp_t allocation, char **ppc)
1007 {
1008         struct midcomms_node *node;
1009         struct dlm_mhandle *mh;
1010         struct dlm_msg *msg;
1011         int idx;
1012
1013         idx = srcu_read_lock(&nodes_srcu);
1014         node = nodeid2node(nodeid);
1015         if (WARN_ON_ONCE(!node))
1016                 goto err;
1017
1018         /* this is a bug, however we going on and hope it will be resolved */
1019         WARN_ON_ONCE(test_bit(DLM_NODE_FLAG_STOP_TX, &node->flags));
1020
1021         mh = dlm_allocate_mhandle(allocation);
1022         if (!mh)
1023                 goto err;
1024
1025         mh->committed = false;
1026         mh->ack_rcv = NULL;
1027         mh->idx = idx;
1028         mh->node = node;
1029
1030         switch (node->version) {
1031         case DLM_VERSION_3_1:
1032                 msg = dlm_lowcomms_new_msg(nodeid, len, allocation, ppc,
1033                                            NULL, NULL);
1034                 if (!msg) {
1035                         dlm_free_mhandle(mh);
1036                         goto err;
1037                 }
1038
1039                 break;
1040         case DLM_VERSION_3_2:
1041                 /* send ack back if necessary */
1042                 dlm_send_ack_threshold(node, DLM_SEND_ACK_BACK_MSG_THRESHOLD);
1043
1044                 msg = dlm_midcomms_get_msg_3_2(mh, nodeid, len, allocation,
1045                                                ppc);
1046                 if (!msg) {
1047                         dlm_free_mhandle(mh);
1048                         goto err;
1049                 }
1050                 break;
1051         default:
1052                 dlm_free_mhandle(mh);
1053                 WARN_ON_ONCE(1);
1054                 goto err;
1055         }
1056
1057         mh->msg = msg;
1058
1059         /* keep in mind that is a must to call
1060          * dlm_midcomms_commit_msg() which releases
1061          * nodes_srcu using mh->idx which is assumed
1062          * here that the application will call it.
1063          */
1064         return mh;
1065
1066 err:
1067         srcu_read_unlock(&nodes_srcu, idx);
1068         return NULL;
1069 }
1070 #endif
1071
1072 static void dlm_midcomms_commit_msg_3_2_trace(const struct dlm_mhandle *mh,
1073                                               const void *name, int namelen)
1074 {
1075         switch (mh->inner_p->header.h_cmd) {
1076         case DLM_MSG:
1077                 trace_dlm_send_message(mh->node->nodeid, mh->seq,
1078                                        &mh->inner_p->message,
1079                                        name, namelen);
1080                 break;
1081         case DLM_RCOM:
1082                 trace_dlm_send_rcom(mh->node->nodeid, mh->seq,
1083                                     &mh->inner_p->rcom);
1084                 break;
1085         default:
1086                 /* nothing to trace */
1087                 break;
1088         }
1089 }
1090
1091 static void dlm_midcomms_commit_msg_3_2(struct dlm_mhandle *mh,
1092                                         const void *name, int namelen)
1093 {
1094         /* nexthdr chain for fast lookup */
1095         mh->opts->o_nextcmd = mh->inner_p->header.h_cmd;
1096         mh->committed = true;
1097         dlm_midcomms_commit_msg_3_2_trace(mh, name, namelen);
1098         dlm_lowcomms_commit_msg(mh->msg);
1099 }
1100
1101 /* avoid false positive for nodes_srcu, lock was happen in
1102  * dlm_midcomms_get_mhandle
1103  */
1104 #ifndef __CHECKER__
1105 void dlm_midcomms_commit_mhandle(struct dlm_mhandle *mh,
1106                                  const void *name, int namelen)
1107 {
1108
1109         switch (mh->node->version) {
1110         case DLM_VERSION_3_1:
1111                 srcu_read_unlock(&nodes_srcu, mh->idx);
1112
1113                 dlm_lowcomms_commit_msg(mh->msg);
1114                 dlm_lowcomms_put_msg(mh->msg);
1115                 /* mh is not part of rcu list in this case */
1116                 dlm_free_mhandle(mh);
1117                 break;
1118         case DLM_VERSION_3_2:
1119                 /* held rcu read lock here, because we sending the
1120                  * dlm message out, when we do that we could receive
1121                  * an ack back which releases the mhandle and we
1122                  * get a use after free.
1123                  */
1124                 rcu_read_lock();
1125                 dlm_midcomms_commit_msg_3_2(mh, name, namelen);
1126                 srcu_read_unlock(&nodes_srcu, mh->idx);
1127                 rcu_read_unlock();
1128                 break;
1129         default:
1130                 srcu_read_unlock(&nodes_srcu, mh->idx);
1131                 WARN_ON_ONCE(1);
1132                 break;
1133         }
1134 }
1135 #endif
1136
1137 int dlm_midcomms_start(void)
1138 {
1139         return dlm_lowcomms_start();
1140 }
1141
1142 void dlm_midcomms_stop(void)
1143 {
1144         dlm_lowcomms_stop();
1145 }
1146
1147 void dlm_midcomms_init(void)
1148 {
1149         int i;
1150
1151         for (i = 0; i < CONN_HASH_SIZE; i++)
1152                 INIT_HLIST_HEAD(&node_hash[i]);
1153
1154         dlm_lowcomms_init();
1155 }
1156
1157 static void midcomms_node_release(struct rcu_head *rcu)
1158 {
1159         struct midcomms_node *node = container_of(rcu, struct midcomms_node, rcu);
1160
1161         WARN_ON_ONCE(atomic_read(&node->send_queue_cnt));
1162         dlm_send_queue_flush(node);
1163         kfree(node);
1164 }
1165
1166 void dlm_midcomms_exit(void)
1167 {
1168         struct midcomms_node *node;
1169         int i, idx;
1170
1171         idx = srcu_read_lock(&nodes_srcu);
1172         for (i = 0; i < CONN_HASH_SIZE; i++) {
1173                 hlist_for_each_entry_rcu(node, &node_hash[i], hlist) {
1174                         dlm_delete_debug_comms_file(node->debugfs);
1175
1176                         spin_lock(&nodes_lock);
1177                         hlist_del_rcu(&node->hlist);
1178                         spin_unlock(&nodes_lock);
1179
1180                         call_srcu(&nodes_srcu, &node->rcu, midcomms_node_release);
1181                 }
1182         }
1183         srcu_read_unlock(&nodes_srcu, idx);
1184
1185         dlm_lowcomms_exit();
1186 }
1187
1188 static void dlm_act_fin_ack_rcv(struct midcomms_node *node)
1189 {
1190         spin_lock(&node->state_lock);
1191         pr_debug("receive active fin ack from node %d with state %s\n",
1192                  node->nodeid, dlm_state_str(node->state));
1193
1194         switch (node->state) {
1195         case DLM_FIN_WAIT1:
1196                 node->state = DLM_FIN_WAIT2;
1197                 pr_debug("switch node %d to state %s\n",
1198                          node->nodeid, dlm_state_str(node->state));
1199                 break;
1200         case DLM_CLOSING:
1201                 midcomms_node_reset(node);
1202                 pr_debug("switch node %d to state %s\n",
1203                          node->nodeid, dlm_state_str(node->state));
1204                 break;
1205         case DLM_CLOSED:
1206                 /* not valid but somehow we got what we want */
1207                 wake_up(&node->shutdown_wait);
1208                 break;
1209         default:
1210                 spin_unlock(&node->state_lock);
1211                 log_print("%s: unexpected state: %d",
1212                           __func__, node->state);
1213                 WARN_ON_ONCE(1);
1214                 return;
1215         }
1216         spin_unlock(&node->state_lock);
1217 }
1218
1219 void dlm_midcomms_add_member(int nodeid)
1220 {
1221         struct midcomms_node *node;
1222         int idx;
1223
1224         idx = srcu_read_lock(&nodes_srcu);
1225         node = nodeid2node(nodeid);
1226         if (WARN_ON_ONCE(!node)) {
1227                 srcu_read_unlock(&nodes_srcu, idx);
1228                 return;
1229         }
1230
1231         spin_lock(&node->state_lock);
1232         if (!node->users) {
1233                 pr_debug("receive add member from node %d with state %s\n",
1234                          node->nodeid, dlm_state_str(node->state));
1235                 switch (node->state) {
1236                 case DLM_ESTABLISHED:
1237                         break;
1238                 case DLM_CLOSED:
1239                         node->state = DLM_ESTABLISHED;
1240                         pr_debug("switch node %d to state %s\n",
1241                                  node->nodeid, dlm_state_str(node->state));
1242                         break;
1243                 default:
1244                         /* some invalid state passive shutdown
1245                          * was failed, we try to reset and
1246                          * hope it will go on.
1247                          */
1248                         log_print("reset node %d because shutdown stuck",
1249                                   node->nodeid);
1250
1251                         midcomms_node_reset(node);
1252                         node->state = DLM_ESTABLISHED;
1253                         break;
1254                 }
1255         }
1256
1257         node->users++;
1258         pr_debug("node %d users inc count %d\n", nodeid, node->users);
1259         spin_unlock(&node->state_lock);
1260
1261         srcu_read_unlock(&nodes_srcu, idx);
1262 }
1263
1264 void dlm_midcomms_remove_member(int nodeid)
1265 {
1266         struct midcomms_node *node;
1267         int idx;
1268
1269         idx = srcu_read_lock(&nodes_srcu);
1270         node = nodeid2node(nodeid);
1271         /* in case of dlm_midcomms_close() removes node */
1272         if (!node) {
1273                 srcu_read_unlock(&nodes_srcu, idx);
1274                 return;
1275         }
1276
1277         spin_lock(&node->state_lock);
1278         /* case of dlm_midcomms_addr() created node but
1279          * was not added before because dlm_midcomms_close()
1280          * removed the node
1281          */
1282         if (!node->users) {
1283                 spin_unlock(&node->state_lock);
1284                 srcu_read_unlock(&nodes_srcu, idx);
1285                 return;
1286         }
1287
1288         node->users--;
1289         pr_debug("node %d users dec count %d\n", nodeid, node->users);
1290
1291         /* hitting users count to zero means the
1292          * other side is running dlm_midcomms_stop()
1293          * we meet us to have a clean disconnect.
1294          */
1295         if (node->users == 0) {
1296                 pr_debug("receive remove member from node %d with state %s\n",
1297                          node->nodeid, dlm_state_str(node->state));
1298                 switch (node->state) {
1299                 case DLM_ESTABLISHED:
1300                         break;
1301                 case DLM_CLOSE_WAIT:
1302                         /* passive shutdown DLM_LAST_ACK case 2 */
1303                         node->state = DLM_LAST_ACK;
1304                         pr_debug("switch node %d to state %s case 2\n",
1305                                  node->nodeid, dlm_state_str(node->state));
1306                         set_bit(DLM_NODE_FLAG_STOP_RX, &node->flags);
1307                         dlm_send_fin(node, dlm_pas_fin_ack_rcv);
1308                         break;
1309                 case DLM_LAST_ACK:
1310                         /* probably receive fin caught it, do nothing */
1311                         break;
1312                 case DLM_CLOSED:
1313                         /* already gone, do nothing */
1314                         break;
1315                 default:
1316                         log_print("%s: unexpected state: %d",
1317                                   __func__, node->state);
1318                         break;
1319                 }
1320         }
1321         spin_unlock(&node->state_lock);
1322
1323         srcu_read_unlock(&nodes_srcu, idx);
1324 }
1325
1326 void dlm_midcomms_version_wait(void)
1327 {
1328         struct midcomms_node *node;
1329         int i, idx, ret;
1330
1331         idx = srcu_read_lock(&nodes_srcu);
1332         for (i = 0; i < CONN_HASH_SIZE; i++) {
1333                 hlist_for_each_entry_rcu(node, &node_hash[i], hlist) {
1334                         ret = wait_event_timeout(node->shutdown_wait,
1335                                                  node->version != DLM_VERSION_NOT_SET ||
1336                                                  node->state == DLM_CLOSED ||
1337                                                  test_bit(DLM_NODE_FLAG_CLOSE, &node->flags),
1338                                                  DLM_SHUTDOWN_TIMEOUT);
1339                         if (!ret || test_bit(DLM_NODE_FLAG_CLOSE, &node->flags))
1340                                 pr_debug("version wait timed out for node %d with state %s\n",
1341                                          node->nodeid, dlm_state_str(node->state));
1342                 }
1343         }
1344         srcu_read_unlock(&nodes_srcu, idx);
1345 }
1346
1347 static void midcomms_shutdown(struct midcomms_node *node)
1348 {
1349         int ret;
1350
1351         /* old protocol, we don't wait for pending operations */
1352         switch (node->version) {
1353         case DLM_VERSION_3_2:
1354                 break;
1355         default:
1356                 return;
1357         }
1358
1359         spin_lock(&node->state_lock);
1360         pr_debug("receive active shutdown for node %d with state %s\n",
1361                  node->nodeid, dlm_state_str(node->state));
1362         switch (node->state) {
1363         case DLM_ESTABLISHED:
1364                 node->state = DLM_FIN_WAIT1;
1365                 pr_debug("switch node %d to state %s case 2\n",
1366                          node->nodeid, dlm_state_str(node->state));
1367                 dlm_send_fin(node, dlm_act_fin_ack_rcv);
1368                 break;
1369         case DLM_CLOSED:
1370                 /* we have what we want */
1371                 break;
1372         default:
1373                 /* busy to enter DLM_FIN_WAIT1, wait until passive
1374                  * done in shutdown_wait to enter DLM_CLOSED.
1375                  */
1376                 break;
1377         }
1378         spin_unlock(&node->state_lock);
1379
1380         if (DLM_DEBUG_FENCE_TERMINATION)
1381                 msleep(5000);
1382
1383         /* wait for other side dlm + fin */
1384         ret = wait_event_timeout(node->shutdown_wait,
1385                                  node->state == DLM_CLOSED ||
1386                                  test_bit(DLM_NODE_FLAG_CLOSE, &node->flags),
1387                                  DLM_SHUTDOWN_TIMEOUT);
1388         if (!ret)
1389                 pr_debug("active shutdown timed out for node %d with state %s\n",
1390                          node->nodeid, dlm_state_str(node->state));
1391         else
1392                 pr_debug("active shutdown done for node %d with state %s\n",
1393                          node->nodeid, dlm_state_str(node->state));
1394 }
1395
1396 void dlm_midcomms_shutdown(void)
1397 {
1398         struct midcomms_node *node;
1399         int i, idx;
1400
1401         mutex_lock(&close_lock);
1402         idx = srcu_read_lock(&nodes_srcu);
1403         for (i = 0; i < CONN_HASH_SIZE; i++) {
1404                 hlist_for_each_entry_rcu(node, &node_hash[i], hlist) {
1405                         midcomms_shutdown(node);
1406                 }
1407         }
1408
1409         dlm_lowcomms_shutdown();
1410
1411         for (i = 0; i < CONN_HASH_SIZE; i++) {
1412                 hlist_for_each_entry_rcu(node, &node_hash[i], hlist) {
1413                         midcomms_node_reset(node);
1414                 }
1415         }
1416         srcu_read_unlock(&nodes_srcu, idx);
1417         mutex_unlock(&close_lock);
1418 }
1419
1420 int dlm_midcomms_close(int nodeid)
1421 {
1422         struct midcomms_node *node;
1423         int idx, ret;
1424
1425         idx = srcu_read_lock(&nodes_srcu);
1426         /* Abort pending close/remove operation */
1427         node = nodeid2node(nodeid);
1428         if (node) {
1429                 /* let shutdown waiters leave */
1430                 set_bit(DLM_NODE_FLAG_CLOSE, &node->flags);
1431                 wake_up(&node->shutdown_wait);
1432         }
1433         srcu_read_unlock(&nodes_srcu, idx);
1434
1435         synchronize_srcu(&nodes_srcu);
1436
1437         mutex_lock(&close_lock);
1438         idx = srcu_read_lock(&nodes_srcu);
1439         node = nodeid2node(nodeid);
1440         if (!node) {
1441                 srcu_read_unlock(&nodes_srcu, idx);
1442                 mutex_unlock(&close_lock);
1443                 return dlm_lowcomms_close(nodeid);
1444         }
1445
1446         ret = dlm_lowcomms_close(nodeid);
1447         dlm_delete_debug_comms_file(node->debugfs);
1448
1449         spin_lock(&nodes_lock);
1450         hlist_del_rcu(&node->hlist);
1451         spin_unlock(&nodes_lock);
1452         srcu_read_unlock(&nodes_srcu, idx);
1453
1454         /* wait that all readers left until flush send queue */
1455         synchronize_srcu(&nodes_srcu);
1456
1457         /* drop all pending dlm messages, this is fine as
1458          * this function get called when the node is fenced
1459          */
1460         dlm_send_queue_flush(node);
1461
1462         call_srcu(&nodes_srcu, &node->rcu, midcomms_node_release);
1463         mutex_unlock(&close_lock);
1464
1465         return ret;
1466 }
1467
1468 /* debug functionality to send raw dlm msg from user space */
1469 struct dlm_rawmsg_data {
1470         struct midcomms_node *node;
1471         void *buf;
1472 };
1473
1474 static void midcomms_new_rawmsg_cb(void *data)
1475 {
1476         struct dlm_rawmsg_data *rd = data;
1477         struct dlm_header *h = rd->buf;
1478
1479         switch (h->h_version) {
1480         case cpu_to_le32(DLM_VERSION_3_1):
1481                 break;
1482         default:
1483                 switch (h->h_cmd) {
1484                 case DLM_OPTS:
1485                         if (!h->u.h_seq)
1486                                 h->u.h_seq = cpu_to_le32(atomic_fetch_inc(&rd->node->seq_send));
1487                         break;
1488                 default:
1489                         break;
1490                 }
1491                 break;
1492         }
1493 }
1494
1495 int dlm_midcomms_rawmsg_send(struct midcomms_node *node, void *buf,
1496                              int buflen)
1497 {
1498         struct dlm_rawmsg_data rd;
1499         struct dlm_msg *msg;
1500         char *msgbuf;
1501
1502         rd.node = node;
1503         rd.buf = buf;
1504
1505         msg = dlm_lowcomms_new_msg(node->nodeid, buflen, GFP_NOFS,
1506                                    &msgbuf, midcomms_new_rawmsg_cb, &rd);
1507         if (!msg)
1508                 return -ENOMEM;
1509
1510         memcpy(msgbuf, buf, buflen);
1511         dlm_lowcomms_commit_msg(msg);
1512         return 0;
1513 }
1514