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(dlm_mhandle, 0);
 230 }
 231
 232 static inline const char *dlm_state_str(int state)
 233 {
 234         switch (state) {
 235         case DLM_CLOSED:
 236                 return "CLOSED";
 237         case DLM_ESTABLISHED:
 238                 return "ESTABLISHED";
 239         case DLM_FIN_WAIT1:
 240                 return "FIN_WAIT1";
 241         case DLM_FIN_WAIT2:
 242                 return "FIN_WAIT2";
 243         case DLM_CLOSE_WAIT:
 244                 return "CLOSE_WAIT";
 245         case DLM_LAST_ACK:
 246                 return "LAST_ACK";
 247         case DLM_CLOSING:
 248                 return "CLOSING";
 249         default:
 250                 return "UNKNOWN";
 251         }
 252 }
 253
 254 const char *dlm_midcomms_state(struct midcomms_node *node)
 255 {
 256         return dlm_state_str(node->state);
 257 }
 258
 259 unsigned long dlm_midcomms_flags(struct midcomms_node *node)
 260 {
 261         return node->flags;
 262 }
 263
 264 int dlm_midcomms_send_queue_cnt(struct midcomms_node *node)
 265 {
 266         return atomic_read(&node->send_queue_cnt);
 267 }
 268
 269 uint32_t dlm_midcomms_version(struct midcomms_node *node)
 270 {
 271         return node->version;
 272 }
 273
 274 static struct midcomms_node *__find_node(int nodeid, int r)
 275 {
 276         struct midcomms_node *node;
 277
 278         hlist_for_each_entry_rcu(node, &node_hash[r], hlist) {
 279                 if (node->nodeid == nodeid)
 280                         return node;
 281         }
 282
 283         return NULL;
 284 }
 285
 286 static void dlm_mhandle_release(struct rcu_head *rcu)
 287 {
 288         struct dlm_mhandle *mh = container_of(rcu, struct dlm_mhandle, rcu);
 289
 290         dlm_lowcomms_put_msg(mh->msg);
 291         dlm_free_mhandle(mh);
 292 }
 293
 294 static void dlm_mhandle_delete(struct midcomms_node *node,
 295                                struct dlm_mhandle *mh)
 296 {
 297         list_del_rcu(&mh->list);
 298         atomic_dec(&node->send_queue_cnt);
 299         call_rcu(&mh->rcu, dlm_mhandle_release);
 300 }
 301
 302 static void dlm_send_queue_flush(struct midcomms_node *node)
 303 {
 304         struct dlm_mhandle *mh;
 305
 306         pr_debug("flush midcomms send queue of node %d\n", node->nodeid);
 307
 308         rcu_read_lock();
 309         spin_lock_bh(&node->send_queue_lock);
 310         list_for_each_entry_rcu(mh, &node->send_queue, list) {
 311                 dlm_mhandle_delete(node, mh);
 312         }
 313         spin_unlock_bh(&node->send_queue_lock);
 314         rcu_read_unlock();
 315 }
 316
 317 static void midcomms_node_reset(struct midcomms_node *node)
 318 {
 319         pr_debug("reset node %d\n", node->nodeid);
 320
 321         atomic_set(&node->seq_next, DLM_SEQ_INIT);
 322         atomic_set(&node->seq_send, DLM_SEQ_INIT);
 323         atomic_set(&node->ulp_delivered, 0);
 324         node->version = DLM_VERSION_NOT_SET;
 325         node->flags = 0;
 326
 327         dlm_send_queue_flush(node);
 328         node->state = DLM_CLOSED;
 329         wake_up(&node->shutdown_wait);
 330 }
 331
 332 static struct midcomms_node *nodeid2node(int nodeid)
 333 {
 334         return __find_node(nodeid, nodeid_hash(nodeid));
 335 }
 336
 337 int dlm_midcomms_addr(int nodeid, struct sockaddr_storage *addr, int len)
 338 {
 339         int ret, idx, r = nodeid_hash(nodeid);
 340         struct midcomms_node *node;
 341
 342         ret = dlm_lowcomms_addr(nodeid, addr, len);
 343         if (ret)
 344                 return ret;
 345
 346         idx = srcu_read_lock(&nodes_srcu);
 347         node = __find_node(nodeid, r);
 348         if (node) {
 349                 srcu_read_unlock(&nodes_srcu, idx);
 350                 return 0;
 351         }
 352         srcu_read_unlock(&nodes_srcu, idx);
 353
 354         node = kmalloc(sizeof(*node), GFP_NOFS);
 355         if (!node)
 356                 return -ENOMEM;
 357
 358         node->nodeid = nodeid;
 359         spin_lock_init(&node->state_lock);
 360         spin_lock_init(&node->send_queue_lock);
 361         atomic_set(&node->send_queue_cnt, 0);
 362         INIT_LIST_HEAD(&node->send_queue);
 363         init_waitqueue_head(&node->shutdown_wait);
 364         node->users = 0;
 365         midcomms_node_reset(node);
 366
 367         spin_lock_bh(&nodes_lock);
 368         hlist_add_head_rcu(&node->hlist, &node_hash[r]);
 369         spin_unlock_bh(&nodes_lock);
 370
 371         node->debugfs = dlm_create_debug_comms_file(nodeid, node);
 372         return 0;
 373 }
 374
 375 static int dlm_send_ack(int nodeid, uint32_t seq)
 376 {
 377         int mb_len = sizeof(struct dlm_header);
 378         struct dlm_header *m_header;
 379         struct dlm_msg *msg;
 380         char *ppc;
 381
 382         msg = dlm_lowcomms_new_msg(nodeid, mb_len, &ppc, NULL, NULL);
 383         if (!msg)
 384                 return -ENOMEM;
 385
 386         m_header = (struct dlm_header *)ppc;
 387
 388         m_header->h_version = cpu_to_le32(DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
 389         m_header->h_nodeid = cpu_to_le32(dlm_our_nodeid());
 390         m_header->h_length = cpu_to_le16(mb_len);
 391         m_header->h_cmd = DLM_ACK;
 392         m_header->u.h_seq = cpu_to_le32(seq);
 393
 394         dlm_lowcomms_commit_msg(msg);
 395         dlm_lowcomms_put_msg(msg);
 396
 397         return 0;
 398 }
 399
 400 static void dlm_send_ack_threshold(struct midcomms_node *node,
 401                                    uint32_t threshold)
 402 {
 403         uint32_t oval, nval;
 404         bool send_ack;
 405
 406         /* let only send one user trigger threshold to send ack back */
 407         do {
 408                 oval = atomic_read(&node->ulp_delivered);
 409                 send_ack = (oval > threshold);
 410                 /* abort if threshold is not reached */
 411                 if (!send_ack)
 412                         break;
 413
 414                 nval = 0;
 415                 /* try to reset ulp_delivered counter */
 416         } while (atomic_cmpxchg(&node->ulp_delivered, oval, nval) != oval);
 417
 418         if (send_ack)
 419                 dlm_send_ack(node->nodeid, atomic_read(&node->seq_next));
 420 }
 421
 422 static int dlm_send_fin(struct midcomms_node *node,
 423                         void (*ack_rcv)(struct midcomms_node *node))
 424 {
 425         int mb_len = sizeof(struct dlm_header);
 426         struct dlm_header *m_header;
 427         struct dlm_mhandle *mh;
 428         char *ppc;
 429
 430         mh = dlm_midcomms_get_mhandle(node->nodeid, mb_len, &ppc);
 431         if (!mh)
 432                 return -ENOMEM;
 433
 434         set_bit(DLM_NODE_FLAG_STOP_TX, &node->flags);
 435         mh->ack_rcv = ack_rcv;
 436
 437         m_header = (struct dlm_header *)ppc;
 438
 439         m_header->h_version = cpu_to_le32(DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
 440         m_header->h_nodeid = cpu_to_le32(dlm_our_nodeid());
 441         m_header->h_length = cpu_to_le16(mb_len);
 442         m_header->h_cmd = DLM_FIN;
 443
 444         pr_debug("sending fin msg to node %d\n", node->nodeid);
 445         dlm_midcomms_commit_mhandle(mh, NULL, 0);
 446
 447         return 0;
 448 }
 449
 450 static void dlm_receive_ack(struct midcomms_node *node, uint32_t seq)
 451 {
 452         struct dlm_mhandle *mh;
 453
 454         rcu_read_lock();
 455         list_for_each_entry_rcu(mh, &node->send_queue, list) {
 456                 if (before(mh->seq, seq)) {
 457                         if (mh->ack_rcv)
 458                                 mh->ack_rcv(node);
 459                 } else {
 460                         /* send queue should be ordered */
 461                         break;
 462                 }
 463         }
 464
 465         spin_lock_bh(&node->send_queue_lock);
 466         list_for_each_entry_rcu(mh, &node->send_queue, list) {
 467                 if (before(mh->seq, seq)) {
 468                         dlm_mhandle_delete(node, mh);
 469                 } else {
 470                         /* send queue should be ordered */
 471                         break;
 472                 }
 473         }
 474         spin_unlock_bh(&node->send_queue_lock);
 475         rcu_read_unlock();
 476 }
 477
 478 static void dlm_pas_fin_ack_rcv(struct midcomms_node *node)
 479 {
 480         spin_lock_bh(&node->state_lock);
 481         pr_debug("receive passive fin ack from node %d with state %s\n",
 482                  node->nodeid, dlm_state_str(node->state));
 483
 484         switch (node->state) {
 485         case DLM_LAST_ACK:
 486                 /* DLM_CLOSED */
 487                 midcomms_node_reset(node);
 488                 break;
 489         case DLM_CLOSED:
 490                 /* not valid but somehow we got what we want */
 491                 wake_up(&node->shutdown_wait);
 492                 break;
 493         default:
 494                 spin_unlock_bh(&node->state_lock);
 495                 log_print("%s: unexpected state: %d",
 496                           __func__, node->state);
 497                 WARN_ON_ONCE(1);
 498                 return;
 499         }
 500         spin_unlock_bh(&node->state_lock);
 501 }
 502
 503 static void dlm_receive_buffer_3_2_trace(uint32_t seq,
 504                                          const union dlm_packet *p)
 505 {
 506         switch (p->header.h_cmd) {
 507         case DLM_MSG:
 508                 trace_dlm_recv_message(dlm_our_nodeid(), seq, &p->message);
 509                 break;
 510         case DLM_RCOM:
 511                 trace_dlm_recv_rcom(dlm_our_nodeid(), seq, &p->rcom);
 512                 break;
 513         default:
 514                 break;
 515         }
 516 }
 517
 518 static void dlm_midcomms_receive_buffer(const union dlm_packet *p,
 519                                         struct midcomms_node *node,
 520                                         uint32_t seq)
 521 {
 522         bool is_expected_seq;
 523         uint32_t oval, nval;
 524
 525         do {
 526                 oval = atomic_read(&node->seq_next);
 527                 is_expected_seq = (oval == seq);
 528                 if (!is_expected_seq)
 529                         break;
 530
 531                 nval = oval + 1;
 532         } while (atomic_cmpxchg(&node->seq_next, oval, nval) != oval);
 533
 534         if (is_expected_seq) {
 535                 switch (p->header.h_cmd) {
 536                 case DLM_FIN:
 537                         spin_lock_bh(&node->state_lock);
 538                         pr_debug("receive fin msg from node %d with state %s\n",
 539                                  node->nodeid, dlm_state_str(node->state));
 540
 541                         switch (node->state) {
 542                         case DLM_ESTABLISHED:
 543                                 dlm_send_ack(node->nodeid, nval);
 544
 545                                 /* passive shutdown DLM_LAST_ACK case 1
 546                                  * additional we check if the node is used by
 547                                  * cluster manager events at all.
 548                                  */
 549                                 if (node->users == 0) {
 550                                         node->state = DLM_LAST_ACK;
 551                                         pr_debug("switch node %d to state %s case 1\n",
 552                                                  node->nodeid, dlm_state_str(node->state));
 553                                         set_bit(DLM_NODE_FLAG_STOP_RX, &node->flags);
 554                                         dlm_send_fin(node, dlm_pas_fin_ack_rcv);
 555                                 } else {
 556                                         node->state = DLM_CLOSE_WAIT;
 557                                         pr_debug("switch node %d to state %s\n",
 558                                                  node->nodeid, dlm_state_str(node->state));
 559                                 }
 560                                 break;
 561                         case DLM_FIN_WAIT1:
 562                                 dlm_send_ack(node->nodeid, nval);
 563                                 node->state = DLM_CLOSING;
 564                                 set_bit(DLM_NODE_FLAG_STOP_RX, &node->flags);
 565                                 pr_debug("switch node %d to state %s\n",
 566                                          node->nodeid, dlm_state_str(node->state));
 567                                 break;
 568                         case DLM_FIN_WAIT2:
 569                                 dlm_send_ack(node->nodeid, nval);
 570                                 midcomms_node_reset(node);
 571                                 pr_debug("switch node %d to state %s\n",
 572                                          node->nodeid, dlm_state_str(node->state));
 573                                 break;
 574                         case DLM_LAST_ACK:
 575                                 /* probably remove_member caught it, do nothing */
 576                                 break;
 577                         default:
 578                                 spin_unlock_bh(&node->state_lock);
 579                                 log_print("%s: unexpected state: %d",
 580                                           __func__, node->state);
 581                                 WARN_ON_ONCE(1);
 582                                 return;
 583                         }
 584                         spin_unlock_bh(&node->state_lock);
 585                         break;
 586                 default:
 587                         WARN_ON_ONCE(test_bit(DLM_NODE_FLAG_STOP_RX, &node->flags));
 588                         dlm_receive_buffer_3_2_trace(seq, p);
 589                         dlm_receive_buffer(p, node->nodeid);
 590                         atomic_inc(&node->ulp_delivered);
 591                         /* unlikely case to send ack back when we don't transmit */
 592                         dlm_send_ack_threshold(node, DLM_RECV_ACK_BACK_MSG_THRESHOLD);
 593                         break;
 594                 }
 595         } else {
 596                 /* retry to ack message which we already have by sending back
 597                  * current node->seq_next number as ack.
 598                  */
 599                 if (seq < oval)
 600                         dlm_send_ack(node->nodeid, oval);
 601
 602                 log_print_ratelimited("ignore dlm msg because seq mismatch, seq: %u, expected: %u, nodeid: %d",
 603                                       seq, oval, node->nodeid);
 604         }
 605 }
 606
 607 static int dlm_opts_check_msglen(const union dlm_packet *p, uint16_t msglen,
 608                                  int nodeid)
 609 {
 610         int len = msglen;
 611
 612         /* we only trust outer header msglen because
 613          * it's checked against receive buffer length.
 614          */
 615         if (len < sizeof(struct dlm_opts))
 616                 return -1;
 617         len -= sizeof(struct dlm_opts);
 618
 619         if (len < le16_to_cpu(p->opts.o_optlen))
 620                 return -1;
 621         len -= le16_to_cpu(p->opts.o_optlen);
 622
 623         switch (p->opts.o_nextcmd) {
 624         case DLM_FIN:
 625                 if (len < sizeof(struct dlm_header)) {
 626                         log_print("fin too small: %d, will skip this message from node %d",
 627                                   len, nodeid);
 628                         return -1;
 629                 }
 630
 631                 break;
 632         case DLM_MSG:
 633                 if (len < sizeof(struct dlm_message)) {
 634                         log_print("msg too small: %d, will skip this message from node %d",
 635                                   msglen, nodeid);
 636                         return -1;
 637                 }
 638
 639                 break;
 640         case DLM_RCOM:
 641                 if (len < sizeof(struct dlm_rcom)) {
 642                         log_print("rcom msg too small: %d, will skip this message from node %d",
 643                                   len, nodeid);
 644                         return -1;
 645                 }
 646
 647                 break;
 648         default:
 649                 log_print("unsupported o_nextcmd received: %u, will skip this message from node %d",
 650                           p->opts.o_nextcmd, nodeid);
 651                 return -1;
 652         }
 653
 654         return 0;
 655 }
 656
 657 static void dlm_midcomms_receive_buffer_3_2(const union dlm_packet *p, int nodeid)
 658 {
 659         uint16_t msglen = le16_to_cpu(p->header.h_length);
 660         struct midcomms_node *node;
 661         uint32_t seq;
 662         int ret, idx;
 663
 664         idx = srcu_read_lock(&nodes_srcu);
 665         node = nodeid2node(nodeid);
 666         if (WARN_ON_ONCE(!node))
 667                 goto out;
 668
 669         switch (node->version) {
 670         case DLM_VERSION_NOT_SET:
 671                 node->version = DLM_VERSION_3_2;
 672                 wake_up(&node->shutdown_wait);
 673                 log_print("version 0x%08x for node %d detected", DLM_VERSION_3_2,
 674                           node->nodeid);
 675
 676                 spin_lock(&node->state_lock);
 677                 switch (node->state) {
 678                 case DLM_CLOSED:
 679                         node->state = DLM_ESTABLISHED;
 680                         pr_debug("switch node %d to state %s\n",
 681                                  node->nodeid, dlm_state_str(node->state));
 682                         break;
 683                 default:
 684                         break;
 685                 }
 686                 spin_unlock(&node->state_lock);
 687
 688                 break;
 689         case DLM_VERSION_3_2:
 690                 break;
 691         default:
 692                 log_print_ratelimited("version mismatch detected, assumed 0x%08x but node %d has 0x%08x",
 693                                       DLM_VERSION_3_2, node->nodeid, node->version);
 694                 goto out;
 695         }
 696
 697         switch (p->header.h_cmd) {
 698         case DLM_RCOM:
 699                 /* these rcom message we use to determine version.
 700                  * they have their own retransmission handling and
 701                  * are the first messages of dlm.
 702                  *
 703                  * length already checked.
 704                  */
 705                 switch (p->rcom.rc_type) {
 706                 case cpu_to_le32(DLM_RCOM_NAMES):
 707                         fallthrough;
 708                 case cpu_to_le32(DLM_RCOM_NAMES_REPLY):
 709                         fallthrough;
 710                 case cpu_to_le32(DLM_RCOM_STATUS):
 711                         fallthrough;
 712                 case cpu_to_le32(DLM_RCOM_STATUS_REPLY):
 713                         break;
 714                 default:
 715                         log_print("unsupported rcom type received: %u, will skip this message from node %d",
 716                                   le32_to_cpu(p->rcom.rc_type), nodeid);
 717                         goto out;
 718                 }
 719
 720                 WARN_ON_ONCE(test_bit(DLM_NODE_FLAG_STOP_RX, &node->flags));
 721                 dlm_receive_buffer(p, nodeid);
 722                 break;
 723         case DLM_OPTS:
 724                 seq = le32_to_cpu(p->header.u.h_seq);
 725
 726                 ret = dlm_opts_check_msglen(p, msglen, nodeid);
 727                 if (ret < 0) {
 728                         log_print("opts msg too small: %u, will skip this message from node %d",
 729                                   msglen, nodeid);
 730                         goto out;
 731                 }
 732
 733                 p = (union dlm_packet *)((unsigned char *)p->opts.o_opts +
 734                                          le16_to_cpu(p->opts.o_optlen));
 735
 736                 /* recheck inner msglen just if it's not garbage */
 737                 msglen = le16_to_cpu(p->header.h_length);
 738                 switch (p->header.h_cmd) {
 739                 case DLM_RCOM:
 740                         if (msglen < sizeof(struct dlm_rcom)) {
 741                                 log_print("inner rcom msg too small: %u, will skip this message from node %d",
 742                                           msglen, nodeid);
 743                                 goto out;
 744                         }
 745
 746                         break;
 747                 case DLM_MSG:
 748                         if (msglen < sizeof(struct dlm_message)) {
 749                                 log_print("inner msg too small: %u, will skip this message from node %d",
 750                                           msglen, nodeid);
 751                                 goto out;
 752                         }
 753
 754                         break;
 755                 case DLM_FIN:
 756                         if (msglen < sizeof(struct dlm_header)) {
 757                                 log_print("inner fin too small: %u, will skip this message from node %d",
 758                                           msglen, nodeid);
 759                                 goto out;
 760                         }
 761
 762                         break;
 763                 default:
 764                         log_print("unsupported inner h_cmd received: %u, will skip this message from node %d",
 765                                   msglen, nodeid);
 766                         goto out;
 767                 }
 768
 769                 dlm_midcomms_receive_buffer(p, node, seq);
 770                 break;
 771         case DLM_ACK:
 772                 seq = le32_to_cpu(p->header.u.h_seq);
 773                 dlm_receive_ack(node, seq);
 774                 break;
 775         default:
 776                 log_print("unsupported h_cmd received: %u, will skip this message from node %d",
 777                           p->header.h_cmd, nodeid);
 778                 break;
 779         }
 780
 781 out:
 782         srcu_read_unlock(&nodes_srcu, idx);
 783 }
 784
 785 static void dlm_midcomms_receive_buffer_3_1(const union dlm_packet *p, int nodeid)
 786 {
 787         uint16_t msglen = le16_to_cpu(p->header.h_length);
 788         struct midcomms_node *node;
 789         int idx;
 790
 791         idx = srcu_read_lock(&nodes_srcu);
 792         node = nodeid2node(nodeid);
 793         if (WARN_ON_ONCE(!node)) {
 794                 srcu_read_unlock(&nodes_srcu, idx);
 795                 return;
 796         }
 797
 798         switch (node->version) {
 799         case DLM_VERSION_NOT_SET:
 800                 node->version = DLM_VERSION_3_1;
 801                 wake_up(&node->shutdown_wait);
 802                 log_print("version 0x%08x for node %d detected", DLM_VERSION_3_1,
 803                           node->nodeid);
 804                 break;
 805         case DLM_VERSION_3_1:
 806                 break;
 807         default:
 808                 log_print_ratelimited("version mismatch detected, assumed 0x%08x but node %d has 0x%08x",
 809                                       DLM_VERSION_3_1, node->nodeid, node->version);
 810                 srcu_read_unlock(&nodes_srcu, idx);
 811                 return;
 812         }
 813         srcu_read_unlock(&nodes_srcu, idx);
 814
 815         switch (p->header.h_cmd) {
 816         case DLM_RCOM:
 817                 /* length already checked */
 818                 break;
 819         case DLM_MSG:
 820                 if (msglen < sizeof(struct dlm_message)) {
 821                         log_print("msg too small: %u, will skip this message from node %d",
 822                                   msglen, nodeid);
 823                         return;
 824                 }
 825
 826                 break;
 827         default:
 828                 log_print("unsupported h_cmd received: %u, will skip this message from node %d",
 829                           p->header.h_cmd, nodeid);
 830                 return;
 831         }
 832
 833         dlm_receive_buffer(p, nodeid);
 834 }
 835
 836 int dlm_validate_incoming_buffer(int nodeid, unsigned char *buf, int len)
 837 {
 838         const unsigned char *ptr = buf;
 839         const struct dlm_header *hd;
 840         uint16_t msglen;
 841         int ret = 0;
 842
 843         while (len >= sizeof(struct dlm_header)) {
 844                 hd = (struct dlm_header *)ptr;
 845
 846                 /* no message should be more than DLM_MAX_SOCKET_BUFSIZE or
 847                  * less than dlm_header size.
 848                  *
 849                  * Some messages does not have a 8 byte length boundary yet
 850                  * which can occur in a unaligned memory access of some dlm
 851                  * messages. However this problem need to be fixed at the
 852                  * sending side, for now it seems nobody run into architecture
 853                  * related issues yet but it slows down some processing.
 854                  * Fixing this issue should be scheduled in future by doing
 855                  * the next major version bump.
 856                  */
 857                 msglen = le16_to_cpu(hd->h_length);
 858                 if (msglen > DLM_MAX_SOCKET_BUFSIZE ||
 859                     msglen < sizeof(struct dlm_header)) {
 860                         log_print("received invalid length header: %u from node %d, will abort message parsing",
 861                                   msglen, nodeid);
 862                         return -EBADMSG;
 863                 }
 864
 865                 /* caller will take care that leftover
 866                  * will be parsed next call with more data
 867                  */
 868                 if (msglen > len)
 869                         break;
 870
 871                 ret += msglen;
 872                 len -= msglen;
 873                 ptr += msglen;
 874         }
 875
 876         return ret;
 877 }
 878
 879 /*
 880  * Called from the low-level comms layer to process a buffer of
 881  * commands.
 882  */
 883 int dlm_process_incoming_buffer(int nodeid, unsigned char *buf, int len)
 884 {
 885         const unsigned char *ptr = buf;
 886         const struct dlm_header *hd;
 887         uint16_t msglen;
 888         int ret = 0;
 889
 890         while (len >= sizeof(struct dlm_header)) {
 891                 hd = (struct dlm_header *)ptr;
 892
 893                 msglen = le16_to_cpu(hd->h_length);
 894                 if (msglen > len)
 895                         break;
 896
 897                 switch (hd->h_version) {
 898                 case cpu_to_le32(DLM_VERSION_3_1):
 899                         dlm_midcomms_receive_buffer_3_1((const union dlm_packet *)ptr, nodeid);
 900                         break;
 901                 case cpu_to_le32(DLM_VERSION_3_2):
 902                         dlm_midcomms_receive_buffer_3_2((const union dlm_packet *)ptr, nodeid);
 903                         break;
 904                 default:
 905                         log_print("received invalid version header: %u from node %d, will skip this message",
 906                                   le32_to_cpu(hd->h_version), nodeid);
 907                         break;
 908                 }
 909
 910                 ret += msglen;
 911                 len -= msglen;
 912                 ptr += msglen;
 913         }
 914
 915         return ret;
 916 }
 917
 918 void dlm_midcomms_unack_msg_resend(int nodeid)
 919 {
 920         struct midcomms_node *node;
 921         struct dlm_mhandle *mh;
 922         int idx, ret;
 923
 924         idx = srcu_read_lock(&nodes_srcu);
 925         node = nodeid2node(nodeid);
 926         if (WARN_ON_ONCE(!node)) {
 927                 srcu_read_unlock(&nodes_srcu, idx);
 928                 return;
 929         }
 930
 931         /* old protocol, we don't support to retransmit on failure */
 932         switch (node->version) {
 933         case DLM_VERSION_3_2:
 934                 break;
 935         default:
 936                 srcu_read_unlock(&nodes_srcu, idx);
 937                 return;
 938         }
 939
 940         rcu_read_lock();
 941         list_for_each_entry_rcu(mh, &node->send_queue, list) {
 942                 if (!mh->committed)
 943                         continue;
 944
 945                 ret = dlm_lowcomms_resend_msg(mh->msg);
 946                 if (!ret)
 947                         log_print_ratelimited("retransmit dlm msg, seq %u, nodeid %d",
 948                                               mh->seq, node->nodeid);
 949         }
 950         rcu_read_unlock();
 951         srcu_read_unlock(&nodes_srcu, idx);
 952 }
 953
 954 static void dlm_fill_opts_header(struct dlm_opts *opts, uint16_t inner_len,
 955                                  uint32_t seq)
 956 {
 957         opts->o_header.h_cmd = DLM_OPTS;
 958         opts->o_header.h_version = cpu_to_le32(DLM_HEADER_MAJOR | DLM_HEADER_MINOR);
 959         opts->o_header.h_nodeid = cpu_to_le32(dlm_our_nodeid());
 960         opts->o_header.h_length = cpu_to_le16(DLM_MIDCOMMS_OPT_LEN + inner_len);
 961         opts->o_header.u.h_seq = cpu_to_le32(seq);
 962 }
 963
 964 static void midcomms_new_msg_cb(void *data)
 965 {
 966         struct dlm_mhandle *mh = data;
 967
 968         atomic_inc(&mh->node->send_queue_cnt);
 969
 970         spin_lock_bh(&mh->node->send_queue_lock);
 971         list_add_tail_rcu(&mh->list, &mh->node->send_queue);
 972         spin_unlock_bh(&mh->node->send_queue_lock);
 973
 974         mh->seq = atomic_fetch_inc(&mh->node->seq_send);
 975 }
 976
 977 static struct dlm_msg *dlm_midcomms_get_msg_3_2(struct dlm_mhandle *mh, int nodeid,
 978                                                 int len, char **ppc)
 979 {
 980         struct dlm_opts *opts;
 981         struct dlm_msg *msg;
 982
 983         msg = dlm_lowcomms_new_msg(nodeid, len + DLM_MIDCOMMS_OPT_LEN,
 984                                    ppc, midcomms_new_msg_cb, mh);
 985         if (!msg)
 986                 return NULL;
 987
 988         opts = (struct dlm_opts *)*ppc;
 989         mh->opts = opts;
 990
 991         /* add possible options here */
 992         dlm_fill_opts_header(opts, len, mh->seq);
 993
 994         *ppc += sizeof(*opts);
 995         mh->inner_p = (const union dlm_packet *)*ppc;
 996         return msg;
 997 }
 998
 999 /* avoid false positive for nodes_srcu, unlock happens in
1000  * dlm_midcomms_commit_mhandle which is a must call if success
1001  */
1002 #ifndef __CHECKER__
1003 struct dlm_mhandle *dlm_midcomms_get_mhandle(int nodeid, int len, char **ppc)
1004 {
1005         struct midcomms_node *node;
1006         struct dlm_mhandle *mh;
1007         struct dlm_msg *msg;
1008         int idx;
1009
1010         idx = srcu_read_lock(&nodes_srcu);
1011         node = nodeid2node(nodeid);
1012         if (WARN_ON_ONCE(!node))
1013                 goto err;
1014
1015         /* this is a bug, however we going on and hope it will be resolved */
1016         WARN_ON_ONCE(test_bit(DLM_NODE_FLAG_STOP_TX, &node->flags));
1017
1018         mh = dlm_allocate_mhandle();
1019         if (!mh)
1020                 goto err;
1021
1022         mh->committed = false;
1023         mh->ack_rcv = NULL;
1024         mh->idx = idx;
1025         mh->node = node;
1026
1027         switch (node->version) {
1028         case DLM_VERSION_3_1:
1029                 msg = dlm_lowcomms_new_msg(nodeid, len, ppc, NULL, NULL);
1030                 if (!msg) {
1031                         dlm_free_mhandle(mh);
1032                         goto err;
1033                 }
1034
1035                 break;
1036         case DLM_VERSION_3_2:
1037                 /* send ack back if necessary */
1038                 dlm_send_ack_threshold(node, DLM_SEND_ACK_BACK_MSG_THRESHOLD);
1039
1040                 msg = dlm_midcomms_get_msg_3_2(mh, nodeid, len, ppc);
1041                 if (!msg) {
1042                         dlm_free_mhandle(mh);
1043                         goto err;
1044                 }
1045                 break;
1046         default:
1047                 dlm_free_mhandle(mh);
1048                 WARN_ON_ONCE(1);
1049                 goto err;
1050         }
1051
1052         mh->msg = msg;
1053
1054         /* keep in mind that is a must to call
1055          * dlm_midcomms_commit_msg() which releases
1056          * nodes_srcu using mh->idx which is assumed
1057          * here that the application will call it.
1058          */
1059         return mh;
1060
1061 err:
1062         srcu_read_unlock(&nodes_srcu, idx);
1063         return NULL;
1064 }
1065 #endif
1066
1067 static void dlm_midcomms_commit_msg_3_2_trace(const struct dlm_mhandle *mh,
1068                                               const void *name, int namelen)
1069 {
1070         switch (mh->inner_p->header.h_cmd) {
1071         case DLM_MSG:
1072                 trace_dlm_send_message(mh->node->nodeid, mh->seq,
1073                                        &mh->inner_p->message,
1074                                        name, namelen);
1075                 break;
1076         case DLM_RCOM:
1077                 trace_dlm_send_rcom(mh->node->nodeid, mh->seq,
1078                                     &mh->inner_p->rcom);
1079                 break;
1080         default:
1081                 /* nothing to trace */
1082                 break;
1083         }
1084 }
1085
1086 static void dlm_midcomms_commit_msg_3_2(struct dlm_mhandle *mh,
1087                                         const void *name, int namelen)
1088 {
1089         /* nexthdr chain for fast lookup */
1090         mh->opts->o_nextcmd = mh->inner_p->header.h_cmd;
1091         mh->committed = true;
1092         dlm_midcomms_commit_msg_3_2_trace(mh, name, namelen);
1093         dlm_lowcomms_commit_msg(mh->msg);
1094 }
1095
1096 /* avoid false positive for nodes_srcu, lock was happen in
1097  * dlm_midcomms_get_mhandle
1098  */
1099 #ifndef __CHECKER__
1100 void dlm_midcomms_commit_mhandle(struct dlm_mhandle *mh,
1101                                  const void *name, int namelen)
1102 {
1103
1104         switch (mh->node->version) {
1105         case DLM_VERSION_3_1:
1106                 srcu_read_unlock(&nodes_srcu, mh->idx);
1107
1108                 dlm_lowcomms_commit_msg(mh->msg);
1109                 dlm_lowcomms_put_msg(mh->msg);
1110                 /* mh is not part of rcu list in this case */
1111                 dlm_free_mhandle(mh);
1112                 break;
1113         case DLM_VERSION_3_2:
1114                 /* held rcu read lock here, because we sending the
1115                  * dlm message out, when we do that we could receive
1116                  * an ack back which releases the mhandle and we
1117                  * get a use after free.
1118                  */
1119                 rcu_read_lock();
1120                 dlm_midcomms_commit_msg_3_2(mh, name, namelen);
1121                 srcu_read_unlock(&nodes_srcu, mh->idx);
1122                 rcu_read_unlock();
1123                 break;
1124         default:
1125                 srcu_read_unlock(&nodes_srcu, mh->idx);
1126                 WARN_ON_ONCE(1);
1127                 break;
1128         }
1129 }
1130 #endif
1131
1132 int dlm_midcomms_start(void)
1133 {
1134         return dlm_lowcomms_start();
1135 }
1136
1137 void dlm_midcomms_stop(void)
1138 {
1139         dlm_lowcomms_stop();
1140 }
1141
1142 void dlm_midcomms_init(void)
1143 {
1144         int i;
1145
1146         for (i = 0; i < CONN_HASH_SIZE; i++)
1147                 INIT_HLIST_HEAD(&node_hash[i]);
1148
1149         dlm_lowcomms_init();
1150 }
1151
1152 static void midcomms_node_release(struct rcu_head *rcu)
1153 {
1154         struct midcomms_node *node = container_of(rcu, struct midcomms_node, rcu);
1155
1156         WARN_ON_ONCE(atomic_read(&node->send_queue_cnt));
1157         dlm_send_queue_flush(node);
1158         kfree(node);
1159 }
1160
1161 void dlm_midcomms_exit(void)
1162 {
1163         struct midcomms_node *node;
1164         int i, idx;
1165
1166         idx = srcu_read_lock(&nodes_srcu);
1167         for (i = 0; i < CONN_HASH_SIZE; i++) {
1168                 hlist_for_each_entry_rcu(node, &node_hash[i], hlist) {
1169                         dlm_delete_debug_comms_file(node->debugfs);
1170
1171                         spin_lock(&nodes_lock);
1172                         hlist_del_rcu(&node->hlist);
1173                         spin_unlock(&nodes_lock);
1174
1175                         call_srcu(&nodes_srcu, &node->rcu, midcomms_node_release);
1176                 }
1177         }
1178         srcu_read_unlock(&nodes_srcu, idx);
1179
1180         dlm_lowcomms_exit();
1181 }
1182
1183 static void dlm_act_fin_ack_rcv(struct midcomms_node *node)
1184 {
1185         spin_lock_bh(&node->state_lock);
1186         pr_debug("receive active fin ack from node %d with state %s\n",
1187                  node->nodeid, dlm_state_str(node->state));
1188
1189         switch (node->state) {
1190         case DLM_FIN_WAIT1:
1191                 node->state = DLM_FIN_WAIT2;
1192                 pr_debug("switch node %d to state %s\n",
1193                          node->nodeid, dlm_state_str(node->state));
1194                 break;
1195         case DLM_CLOSING:
1196                 midcomms_node_reset(node);
1197                 pr_debug("switch node %d to state %s\n",
1198                          node->nodeid, dlm_state_str(node->state));
1199                 break;
1200         case DLM_CLOSED:
1201                 /* not valid but somehow we got what we want */
1202                 wake_up(&node->shutdown_wait);
1203                 break;
1204         default:
1205                 spin_unlock_bh(&node->state_lock);
1206                 log_print("%s: unexpected state: %d",
1207                           __func__, node->state);
1208                 WARN_ON_ONCE(1);
1209                 return;
1210         }
1211         spin_unlock_bh(&node->state_lock);
1212 }
1213
1214 void dlm_midcomms_add_member(int nodeid)
1215 {
1216         struct midcomms_node *node;
1217         int idx;
1218
1219         idx = srcu_read_lock(&nodes_srcu);
1220         node = nodeid2node(nodeid);
1221         if (WARN_ON_ONCE(!node)) {
1222                 srcu_read_unlock(&nodes_srcu, idx);
1223                 return;
1224         }
1225
1226         spin_lock_bh(&node->state_lock);
1227         if (!node->users) {
1228                 pr_debug("receive add member from node %d with state %s\n",
1229                          node->nodeid, dlm_state_str(node->state));
1230                 switch (node->state) {
1231                 case DLM_ESTABLISHED:
1232                         break;
1233                 case DLM_CLOSED:
1234                         node->state = DLM_ESTABLISHED;
1235                         pr_debug("switch node %d to state %s\n",
1236                                  node->nodeid, dlm_state_str(node->state));
1237                         break;
1238                 default:
1239                         /* some invalid state passive shutdown
1240                          * was failed, we try to reset and
1241                          * hope it will go on.
1242                          */
1243                         log_print("reset node %d because shutdown stuck",
1244                                   node->nodeid);
1245
1246                         midcomms_node_reset(node);
1247                         node->state = DLM_ESTABLISHED;
1248                         break;
1249                 }
1250         }
1251
1252         node->users++;
1253         pr_debug("node %d users inc count %d\n", nodeid, node->users);
1254         spin_unlock_bh(&node->state_lock);
1255
1256         srcu_read_unlock(&nodes_srcu, idx);
1257 }
1258
1259 void dlm_midcomms_remove_member(int nodeid)
1260 {
1261         struct midcomms_node *node;
1262         int idx;
1263
1264         idx = srcu_read_lock(&nodes_srcu);
1265         node = nodeid2node(nodeid);
1266         /* in case of dlm_midcomms_close() removes node */
1267         if (!node) {
1268                 srcu_read_unlock(&nodes_srcu, idx);
1269                 return;
1270         }
1271
1272         spin_lock_bh(&node->state_lock);
1273         /* case of dlm_midcomms_addr() created node but
1274          * was not added before because dlm_midcomms_close()
1275          * removed the node
1276          */
1277         if (!node->users) {
1278                 spin_unlock_bh(&node->state_lock);
1279                 srcu_read_unlock(&nodes_srcu, idx);
1280                 return;
1281         }
1282
1283         node->users--;
1284         pr_debug("node %d users dec count %d\n", nodeid, node->users);
1285
1286         /* hitting users count to zero means the
1287          * other side is running dlm_midcomms_stop()
1288          * we meet us to have a clean disconnect.
1289          */
1290         if (node->users == 0) {
1291                 pr_debug("receive remove member from node %d with state %s\n",
1292                          node->nodeid, dlm_state_str(node->state));
1293                 switch (node->state) {
1294                 case DLM_ESTABLISHED:
1295                         break;
1296                 case DLM_CLOSE_WAIT:
1297                         /* passive shutdown DLM_LAST_ACK case 2 */
1298                         node->state = DLM_LAST_ACK;
1299                         pr_debug("switch node %d to state %s case 2\n",
1300                                  node->nodeid, dlm_state_str(node->state));
1301                         set_bit(DLM_NODE_FLAG_STOP_RX, &node->flags);
1302                         dlm_send_fin(node, dlm_pas_fin_ack_rcv);
1303                         break;
1304                 case DLM_LAST_ACK:
1305                         /* probably receive fin caught it, do nothing */
1306                         break;
1307                 case DLM_CLOSED:
1308                         /* already gone, do nothing */
1309                         break;
1310                 default:
1311                         log_print("%s: unexpected state: %d",
1312                                   __func__, node->state);
1313                         break;
1314                 }
1315         }
1316         spin_unlock_bh(&node->state_lock);
1317
1318         srcu_read_unlock(&nodes_srcu, idx);
1319 }
1320
1321 void dlm_midcomms_version_wait(void)
1322 {
1323         struct midcomms_node *node;
1324         int i, idx, ret;
1325
1326         idx = srcu_read_lock(&nodes_srcu);
1327         for (i = 0; i < CONN_HASH_SIZE; i++) {
1328                 hlist_for_each_entry_rcu(node, &node_hash[i], hlist) {
1329                         ret = wait_event_timeout(node->shutdown_wait,
1330                                                  node->version != DLM_VERSION_NOT_SET ||
1331                                                  node->state == DLM_CLOSED ||
1332                                                  test_bit(DLM_NODE_FLAG_CLOSE, &node->flags),
1333                                                  DLM_SHUTDOWN_TIMEOUT);
1334                         if (!ret || test_bit(DLM_NODE_FLAG_CLOSE, &node->flags))
1335                                 pr_debug("version wait timed out for node %d with state %s\n",
1336                                          node->nodeid, dlm_state_str(node->state));
1337                 }
1338         }
1339         srcu_read_unlock(&nodes_srcu, idx);
1340 }
1341
1342 static void midcomms_shutdown(struct midcomms_node *node)
1343 {
1344         int ret;
1345
1346         /* old protocol, we don't wait for pending operations */
1347         switch (node->version) {
1348         case DLM_VERSION_3_2:
1349                 break;
1350         default:
1351                 return;
1352         }
1353
1354         spin_lock_bh(&node->state_lock);
1355         pr_debug("receive active shutdown for node %d with state %s\n",
1356                  node->nodeid, dlm_state_str(node->state));
1357         switch (node->state) {
1358         case DLM_ESTABLISHED:
1359                 node->state = DLM_FIN_WAIT1;
1360                 pr_debug("switch node %d to state %s case 2\n",
1361                          node->nodeid, dlm_state_str(node->state));
1362                 dlm_send_fin(node, dlm_act_fin_ack_rcv);
1363                 break;
1364         case DLM_CLOSED:
1365                 /* we have what we want */
1366                 break;
1367         default:
1368                 /* busy to enter DLM_FIN_WAIT1, wait until passive
1369                  * done in shutdown_wait to enter DLM_CLOSED.
1370                  */
1371                 break;
1372         }
1373         spin_unlock_bh(&node->state_lock);
1374
1375         if (DLM_DEBUG_FENCE_TERMINATION)
1376                 msleep(5000);
1377
1378         /* wait for other side dlm + fin */
1379         ret = wait_event_timeout(node->shutdown_wait,
1380                                  node->state == DLM_CLOSED ||
1381                                  test_bit(DLM_NODE_FLAG_CLOSE, &node->flags),
1382                                  DLM_SHUTDOWN_TIMEOUT);
1383         if (!ret)
1384                 pr_debug("active shutdown timed out for node %d with state %s\n",
1385                          node->nodeid, dlm_state_str(node->state));
1386         else
1387                 pr_debug("active shutdown done for node %d with state %s\n",
1388                          node->nodeid, dlm_state_str(node->state));
1389 }
1390
1391 void dlm_midcomms_shutdown(void)
1392 {
1393         struct midcomms_node *node;
1394         int i, idx;
1395
1396         mutex_lock(&close_lock);
1397         idx = srcu_read_lock(&nodes_srcu);
1398         for (i = 0; i < CONN_HASH_SIZE; i++) {
1399                 hlist_for_each_entry_rcu(node, &node_hash[i], hlist) {
1400                         midcomms_shutdown(node);
1401                 }
1402         }
1403
1404         dlm_lowcomms_shutdown();
1405
1406         for (i = 0; i < CONN_HASH_SIZE; i++) {
1407                 hlist_for_each_entry_rcu(node, &node_hash[i], hlist) {
1408                         midcomms_node_reset(node);
1409                 }
1410         }
1411         srcu_read_unlock(&nodes_srcu, idx);
1412         mutex_unlock(&close_lock);
1413 }
1414
1415 int dlm_midcomms_close(int nodeid)
1416 {
1417         struct midcomms_node *node;
1418         int idx, ret;
1419
1420         idx = srcu_read_lock(&nodes_srcu);
1421         /* Abort pending close/remove operation */
1422         node = nodeid2node(nodeid);
1423         if (node) {
1424                 /* let shutdown waiters leave */
1425                 set_bit(DLM_NODE_FLAG_CLOSE, &node->flags);
1426                 wake_up(&node->shutdown_wait);
1427         }
1428         srcu_read_unlock(&nodes_srcu, idx);
1429
1430         synchronize_srcu(&nodes_srcu);
1431
1432         mutex_lock(&close_lock);
1433         idx = srcu_read_lock(&nodes_srcu);
1434         node = nodeid2node(nodeid);
1435         if (!node) {
1436                 srcu_read_unlock(&nodes_srcu, idx);
1437                 mutex_unlock(&close_lock);
1438                 return dlm_lowcomms_close(nodeid);
1439         }
1440
1441         ret = dlm_lowcomms_close(nodeid);
1442         dlm_delete_debug_comms_file(node->debugfs);
1443
1444         spin_lock_bh(&nodes_lock);
1445         hlist_del_rcu(&node->hlist);
1446         spin_unlock_bh(&nodes_lock);
1447         srcu_read_unlock(&nodes_srcu, idx);
1448
1449         /* wait that all readers left until flush send queue */
1450         synchronize_srcu(&nodes_srcu);
1451
1452         /* drop all pending dlm messages, this is fine as
1453          * this function get called when the node is fenced
1454          */
1455         dlm_send_queue_flush(node);
1456
1457         call_srcu(&nodes_srcu, &node->rcu, midcomms_node_release);
1458         mutex_unlock(&close_lock);
1459
1460         return ret;
1461 }
1462
1463 /* debug functionality to send raw dlm msg from user space */
1464 struct dlm_rawmsg_data {
1465         struct midcomms_node *node;
1466         void *buf;
1467 };
1468
1469 static void midcomms_new_rawmsg_cb(void *data)
1470 {
1471         struct dlm_rawmsg_data *rd = data;
1472         struct dlm_header *h = rd->buf;
1473
1474         switch (h->h_version) {
1475         case cpu_to_le32(DLM_VERSION_3_1):
1476                 break;
1477         default:
1478                 switch (h->h_cmd) {
1479                 case DLM_OPTS:
1480                         if (!h->u.h_seq)
1481                                 h->u.h_seq = cpu_to_le32(atomic_fetch_inc(&rd->node->seq_send));
1482                         break;
1483                 default:
1484                         break;
1485                 }
1486                 break;
1487         }
1488 }
1489
1490 int dlm_midcomms_rawmsg_send(struct midcomms_node *node, void *buf,
1491                              int buflen)
1492 {
1493         struct dlm_rawmsg_data rd;
1494         struct dlm_msg *msg;
1495         char *msgbuf;
1496
1497         rd.node = node;
1498         rd.buf = buf;
1499
1500         msg = dlm_lowcomms_new_msg(node->nodeid, buflen, &msgbuf,
1501                                    midcomms_new_rawmsg_cb, &rd);
1502         if (!msg)
1503                 return -ENOMEM;
1504
1505         memcpy(msgbuf, buf, buflen);
1506         dlm_lowcomms_commit_msg(msg);
1507         return 0;
1508 }
1509