fs/ocfs2/dlm/dlmdomain.c

   1 /* -*- mode: c; c-basic-offset: 8; -*-
   2  * vim: noexpandtab sw=8 ts=8 sts=0:
   3  *
   4  * dlmdomain.c
   5  *
   6  * defines domain join / leave apis
   7  *
   8  * Copyright (C) 2004 Oracle.  All rights reserved.
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public
  12  * License as published by the Free Software Foundation; either
  13  * version 2 of the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public
  21  * License along with this program; if not, write to the
  22  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  23  * Boston, MA 021110-1307, USA.
  24  *
  25  */
  26
  27 #include <linux/module.h>
  28 #include <linux/types.h>
  29 #include <linux/slab.h>
  30 #include <linux/highmem.h>
  31 #include <linux/utsname.h>
  32 #include <linux/init.h>
  33 #include <linux/spinlock.h>
  34 #include <linux/delay.h>
  35 #include <linux/err.h>
  36
  37 #include "cluster/heartbeat.h"
  38 #include "cluster/nodemanager.h"
  39 #include "cluster/tcp.h"
  40
  41 #include "dlmapi.h"
  42 #include "dlmcommon.h"
  43
  44 #include "dlmdebug.h"
  45 #include "dlmdomain.h"
  46
  47 #include "dlmver.h"
  48
  49 #define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_DOMAIN)
  50 #include "cluster/masklog.h"
  51
  52 /*
  53  *
  54  * spinlock lock ordering: if multiple locks are needed, obey this ordering:
  55  *    dlm_domain_lock
  56  *    struct dlm_ctxt->spinlock
  57  *    struct dlm_lock_resource->spinlock
  58  *    struct dlm_ctxt->master_lock
  59  *    struct dlm_ctxt->ast_lock
  60  *    dlm_master_list_entry->spinlock
  61  *    dlm_lock->spinlock
  62  *
  63  */
  64
  65 spinlock_t dlm_domain_lock = SPIN_LOCK_UNLOCKED;
  66 LIST_HEAD(dlm_domains);
  67 static DECLARE_WAIT_QUEUE_HEAD(dlm_domain_events);
  68
  69 #define DLM_DOMAIN_BACKOFF_MS 200
  70
  71 static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data);
  72 static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data);
  73 static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data);
  74 static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data);
  75
  76 static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm);
  77
  78 void __dlm_unhash_lockres(struct dlm_lock_resource *lockres)
  79 {
  80         hlist_del_init(&lockres->hash_node);
  81         dlm_lockres_put(lockres);
  82 }
  83
  84 void __dlm_insert_lockres(struct dlm_ctxt *dlm,
  85                        struct dlm_lock_resource *res)
  86 {
  87         struct hlist_head *bucket;
  88         struct qstr *q;
  89
  90         assert_spin_locked(&dlm->spinlock);
  91
  92         q = &res->lockname;
  93         q->hash = full_name_hash(q->name, q->len);
  94         bucket = &(dlm->lockres_hash[q->hash % DLM_HASH_BUCKETS]);
  95
  96         /* get a reference for our hashtable */
  97         dlm_lockres_get(res);
  98
  99         hlist_add_head(&res->hash_node, bucket);
 100 }
 101
 102 struct dlm_lock_resource * __dlm_lookup_lockres(struct dlm_ctxt *dlm,
 103                                          const char *name,
 104                                          unsigned int len)
 105 {
 106         unsigned int hash;
 107         struct hlist_node *iter;
 108         struct dlm_lock_resource *tmpres=NULL;
 109         struct hlist_head *bucket;
 110
 111         mlog_entry("%.*s\n", len, name);
 112
 113         assert_spin_locked(&dlm->spinlock);
 114
 115         hash = full_name_hash(name, len);
 116
 117         bucket = &(dlm->lockres_hash[hash % DLM_HASH_BUCKETS]);
 118
 119         /* check for pre-existing lock */
 120         hlist_for_each(iter, bucket) {
 121                 tmpres = hlist_entry(iter, struct dlm_lock_resource, hash_node);
 122                 if (tmpres->lockname.len == len &&
 123                     memcmp(tmpres->lockname.name, name, len) == 0) {
 124                         dlm_lockres_get(tmpres);
 125                         break;
 126                 }
 127
 128                 tmpres = NULL;
 129         }
 130         return tmpres;
 131 }
 132
 133 struct dlm_lock_resource * dlm_lookup_lockres(struct dlm_ctxt *dlm,
 134                                     const char *name,
 135                                     unsigned int len)
 136 {
 137         struct dlm_lock_resource *res;
 138
 139         spin_lock(&dlm->spinlock);
 140         res = __dlm_lookup_lockres(dlm, name, len);
 141         spin_unlock(&dlm->spinlock);
 142         return res;
 143 }
 144
 145 static struct dlm_ctxt * __dlm_lookup_domain_full(const char *domain, int len)
 146 {
 147         struct dlm_ctxt *tmp = NULL;
 148         struct list_head *iter;
 149
 150         assert_spin_locked(&dlm_domain_lock);
 151
 152         /* tmp->name here is always NULL terminated,
 153          * but domain may not be! */
 154         list_for_each(iter, &dlm_domains) {
 155                 tmp = list_entry (iter, struct dlm_ctxt, list);
 156                 if (strlen(tmp->name) == len &&
 157                     memcmp(tmp->name, domain, len)==0)
 158                         break;
 159                 tmp = NULL;
 160         }
 161
 162         return tmp;
 163 }
 164
 165 /* For null terminated domain strings ONLY */
 166 static struct dlm_ctxt * __dlm_lookup_domain(const char *domain)
 167 {
 168         assert_spin_locked(&dlm_domain_lock);
 169
 170         return __dlm_lookup_domain_full(domain, strlen(domain));
 171 }
 172
 173
 174 /* returns true on one of two conditions:
 175  * 1) the domain does not exist
 176  * 2) the domain exists and it's state is "joined" */
 177 static int dlm_wait_on_domain_helper(const char *domain)
 178 {
 179         int ret = 0;
 180         struct dlm_ctxt *tmp = NULL;
 181
 182         spin_lock(&dlm_domain_lock);
 183
 184         tmp = __dlm_lookup_domain(domain);
 185         if (!tmp)
 186                 ret = 1;
 187         else if (tmp->dlm_state == DLM_CTXT_JOINED)
 188                 ret = 1;
 189
 190         spin_unlock(&dlm_domain_lock);
 191         return ret;
 192 }
 193
 194 static void dlm_free_ctxt_mem(struct dlm_ctxt *dlm)
 195 {
 196         if (dlm->lockres_hash)
 197                 free_page((unsigned long) dlm->lockres_hash);
 198
 199         if (dlm->name)
 200                 kfree(dlm->name);
 201
 202         kfree(dlm);
 203 }
 204
 205 /* A little strange - this function will be called while holding
 206  * dlm_domain_lock and is expected to be holding it on the way out. We
 207  * will however drop and reacquire it multiple times */
 208 static void dlm_ctxt_release(struct kref *kref)
 209 {
 210         struct dlm_ctxt *dlm;
 211
 212         dlm = container_of(kref, struct dlm_ctxt, dlm_refs);
 213
 214         BUG_ON(dlm->num_joins);
 215         BUG_ON(dlm->dlm_state == DLM_CTXT_JOINED);
 216
 217         /* we may still be in the list if we hit an error during join. */
 218         list_del_init(&dlm->list);
 219
 220         spin_unlock(&dlm_domain_lock);
 221
 222         mlog(0, "freeing memory from domain %s\n", dlm->name);
 223
 224         wake_up(&dlm_domain_events);
 225
 226         dlm_free_ctxt_mem(dlm);
 227
 228         spin_lock(&dlm_domain_lock);
 229 }
 230
 231 void dlm_put(struct dlm_ctxt *dlm)
 232 {
 233         spin_lock(&dlm_domain_lock);
 234         kref_put(&dlm->dlm_refs, dlm_ctxt_release);
 235         spin_unlock(&dlm_domain_lock);
 236 }
 237
 238 static void __dlm_get(struct dlm_ctxt *dlm)
 239 {
 240         kref_get(&dlm->dlm_refs);
 241 }
 242
 243 /* given a questionable reference to a dlm object, gets a reference if
 244  * it can find it in the list, otherwise returns NULL in which case
 245  * you shouldn't trust your pointer. */
 246 struct dlm_ctxt *dlm_grab(struct dlm_ctxt *dlm)
 247 {
 248         struct list_head *iter;
 249         struct dlm_ctxt *target = NULL;
 250
 251         spin_lock(&dlm_domain_lock);
 252
 253         list_for_each(iter, &dlm_domains) {
 254                 target = list_entry (iter, struct dlm_ctxt, list);
 255
 256                 if (target == dlm) {
 257                         __dlm_get(target);
 258                         break;
 259                 }
 260
 261                 target = NULL;
 262         }
 263
 264         spin_unlock(&dlm_domain_lock);
 265
 266         return target;
 267 }
 268
 269 int dlm_domain_fully_joined(struct dlm_ctxt *dlm)
 270 {
 271         int ret;
 272
 273         spin_lock(&dlm_domain_lock);
 274         ret = (dlm->dlm_state == DLM_CTXT_JOINED) ||
 275                 (dlm->dlm_state == DLM_CTXT_IN_SHUTDOWN);
 276         spin_unlock(&dlm_domain_lock);
 277
 278         return ret;
 279 }
 280
 281 static void dlm_complete_dlm_shutdown(struct dlm_ctxt *dlm)
 282 {
 283         dlm_unregister_domain_handlers(dlm);
 284         dlm_complete_thread(dlm);
 285         dlm_complete_recovery_thread(dlm);
 286
 287         /* We've left the domain. Now we can take ourselves out of the
 288          * list and allow the kref stuff to help us free the
 289          * memory. */
 290         spin_lock(&dlm_domain_lock);
 291         list_del_init(&dlm->list);
 292         spin_unlock(&dlm_domain_lock);
 293
 294         /* Wake up anyone waiting for us to remove this domain */
 295         wake_up(&dlm_domain_events);
 296 }
 297
 298 static void dlm_migrate_all_locks(struct dlm_ctxt *dlm)
 299 {
 300         int i;
 301         struct dlm_lock_resource *res;
 302
 303         mlog(0, "Migrating locks from domain %s\n", dlm->name);
 304 restart:
 305         spin_lock(&dlm->spinlock);
 306         for (i = 0; i < DLM_HASH_BUCKETS; i++) {
 307                 while (!hlist_empty(&dlm->lockres_hash[i])) {
 308                         res = hlist_entry(dlm->lockres_hash[i].first,
 309                                           struct dlm_lock_resource, hash_node);
 310                         /* need reference when manually grabbing lockres */
 311                         dlm_lockres_get(res);
 312                         /* this should unhash the lockres
 313                          * and exit with dlm->spinlock */
 314                         mlog(0, "purging res=%p\n", res);
 315                         if (dlm_lockres_is_dirty(dlm, res)) {
 316                                 /* HACK!  this should absolutely go.
 317                                  * need to figure out why some empty
 318                                  * lockreses are still marked dirty */
 319                                 mlog(ML_ERROR, "lockres %.*s dirty!\n",
 320                                      res->lockname.len, res->lockname.name);
 321
 322                                 spin_unlock(&dlm->spinlock);
 323                                 dlm_kick_thread(dlm, res);
 324                                 wait_event(dlm->ast_wq, !dlm_lockres_is_dirty(dlm, res));
 325                                 dlm_lockres_put(res);
 326                                 goto restart;
 327                         }
 328                         dlm_purge_lockres(dlm, res);
 329                         dlm_lockres_put(res);
 330                 }
 331         }
 332         spin_unlock(&dlm->spinlock);
 333
 334         mlog(0, "DONE Migrating locks from domain %s\n", dlm->name);
 335 }
 336
 337 static int dlm_no_joining_node(struct dlm_ctxt *dlm)
 338 {
 339         int ret;
 340
 341         spin_lock(&dlm->spinlock);
 342         ret = dlm->joining_node == DLM_LOCK_RES_OWNER_UNKNOWN;
 343         spin_unlock(&dlm->spinlock);
 344
 345         return ret;
 346 }
 347
 348 static void dlm_mark_domain_leaving(struct dlm_ctxt *dlm)
 349 {
 350         /* Yikes, a double spinlock! I need domain_lock for the dlm
 351          * state and the dlm spinlock for join state... Sorry! */
 352 again:
 353         spin_lock(&dlm_domain_lock);
 354         spin_lock(&dlm->spinlock);
 355
 356         if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
 357                 mlog(0, "Node %d is joining, we wait on it.\n",
 358                           dlm->joining_node);
 359                 spin_unlock(&dlm->spinlock);
 360                 spin_unlock(&dlm_domain_lock);
 361
 362                 wait_event(dlm->dlm_join_events, dlm_no_joining_node(dlm));
 363                 goto again;
 364         }
 365
 366         dlm->dlm_state = DLM_CTXT_LEAVING;
 367         spin_unlock(&dlm->spinlock);
 368         spin_unlock(&dlm_domain_lock);
 369 }
 370
 371 static void __dlm_print_nodes(struct dlm_ctxt *dlm)
 372 {
 373         int node = -1;
 374
 375         assert_spin_locked(&dlm->spinlock);
 376
 377         mlog(ML_NOTICE, "Nodes in my domain (\"%s\"):\n", dlm->name);
 378
 379         while ((node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES,
 380                                      node + 1)) < O2NM_MAX_NODES) {
 381                 mlog(ML_NOTICE, " node %d\n", node);
 382         }
 383 }
 384
 385 static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data)
 386 {
 387         struct dlm_ctxt *dlm = data;
 388         unsigned int node;
 389         struct dlm_exit_domain *exit_msg = (struct dlm_exit_domain *) msg->buf;
 390
 391         mlog_entry("%p %u %p", msg, len, data);
 392
 393         if (!dlm_grab(dlm))
 394                 return 0;
 395
 396         node = exit_msg->node_idx;
 397
 398         mlog(0, "Node %u leaves domain %s\n", node, dlm->name);
 399
 400         spin_lock(&dlm->spinlock);
 401         clear_bit(node, dlm->domain_map);
 402         __dlm_print_nodes(dlm);
 403
 404         /* notify anything attached to the heartbeat events */
 405         dlm_hb_event_notify_attached(dlm, node, 0);
 406
 407         spin_unlock(&dlm->spinlock);
 408
 409         dlm_put(dlm);
 410
 411         return 0;
 412 }
 413
 414 static int dlm_send_one_domain_exit(struct dlm_ctxt *dlm,
 415                                     unsigned int node)
 416 {
 417         int status;
 418         struct dlm_exit_domain leave_msg;
 419
 420         mlog(0, "Asking node %u if we can leave the domain %s me = %u\n",
 421                   node, dlm->name, dlm->node_num);
 422
 423         memset(&leave_msg, 0, sizeof(leave_msg));
 424         leave_msg.node_idx = dlm->node_num;
 425
 426         status = o2net_send_message(DLM_EXIT_DOMAIN_MSG, dlm->key,
 427                                     &leave_msg, sizeof(leave_msg), node,
 428                                     NULL);
 429
 430         mlog(0, "status return %d from o2net_send_message\n", status);
 431
 432         return status;
 433 }
 434
 435
 436 static void dlm_leave_domain(struct dlm_ctxt *dlm)
 437 {
 438         int node, clear_node, status;
 439
 440         /* At this point we've migrated away all our locks and won't
 441          * accept mastership of new ones. The dlm is responsible for
 442          * almost nothing now. We make sure not to confuse any joining
 443          * nodes and then commence shutdown procedure. */
 444
 445         spin_lock(&dlm->spinlock);
 446         /* Clear ourselves from the domain map */
 447         clear_bit(dlm->node_num, dlm->domain_map);
 448         while ((node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES,
 449                                      0)) < O2NM_MAX_NODES) {
 450                 /* Drop the dlm spinlock. This is safe wrt the domain_map.
 451                  * -nodes cannot be added now as the
 452                  *   query_join_handlers knows to respond with OK_NO_MAP
 453                  * -we catch the right network errors if a node is
 454                  *   removed from the map while we're sending him the
 455                  *   exit message. */
 456                 spin_unlock(&dlm->spinlock);
 457
 458                 clear_node = 1;
 459
 460                 status = dlm_send_one_domain_exit(dlm, node);
 461                 if (status < 0 &&
 462                     status != -ENOPROTOOPT &&
 463                     status != -ENOTCONN) {
 464                         mlog(ML_NOTICE, "Error %d sending domain exit message "
 465                              "to node %d\n", status, node);
 466
 467                         /* Not sure what to do here but lets sleep for
 468                          * a bit in case this was a transient
 469                          * error... */
 470                         msleep(DLM_DOMAIN_BACKOFF_MS);
 471                         clear_node = 0;
 472                 }
 473
 474                 spin_lock(&dlm->spinlock);
 475                 /* If we're not clearing the node bit then we intend
 476                  * to loop back around to try again. */
 477                 if (clear_node)
 478                         clear_bit(node, dlm->domain_map);
 479         }
 480         spin_unlock(&dlm->spinlock);
 481 }
 482
 483 int dlm_joined(struct dlm_ctxt *dlm)
 484 {
 485         int ret = 0;
 486
 487         spin_lock(&dlm_domain_lock);
 488
 489         if (dlm->dlm_state == DLM_CTXT_JOINED)
 490                 ret = 1;
 491
 492         spin_unlock(&dlm_domain_lock);
 493
 494         return ret;
 495 }
 496
 497 int dlm_shutting_down(struct dlm_ctxt *dlm)
 498 {
 499         int ret = 0;
 500
 501         spin_lock(&dlm_domain_lock);
 502
 503         if (dlm->dlm_state == DLM_CTXT_IN_SHUTDOWN)
 504                 ret = 1;
 505
 506         spin_unlock(&dlm_domain_lock);
 507
 508         return ret;
 509 }
 510
 511 void dlm_unregister_domain(struct dlm_ctxt *dlm)
 512 {
 513         int leave = 0;
 514
 515         spin_lock(&dlm_domain_lock);
 516         BUG_ON(dlm->dlm_state != DLM_CTXT_JOINED);
 517         BUG_ON(!dlm->num_joins);
 518
 519         dlm->num_joins--;
 520         if (!dlm->num_joins) {
 521                 /* We mark it "in shutdown" now so new register
 522                  * requests wait until we've completely left the
 523                  * domain. Don't use DLM_CTXT_LEAVING yet as we still
 524                  * want new domain joins to communicate with us at
 525                  * least until we've completed migration of our
 526                  * resources. */
 527                 dlm->dlm_state = DLM_CTXT_IN_SHUTDOWN;
 528                 leave = 1;
 529         }
 530         spin_unlock(&dlm_domain_lock);
 531
 532         if (leave) {
 533                 mlog(0, "shutting down domain %s\n", dlm->name);
 534
 535                 /* We changed dlm state, notify the thread */
 536                 dlm_kick_thread(dlm, NULL);
 537
 538                 dlm_migrate_all_locks(dlm);
 539                 dlm_mark_domain_leaving(dlm);
 540                 dlm_leave_domain(dlm);
 541                 dlm_complete_dlm_shutdown(dlm);
 542         }
 543         dlm_put(dlm);
 544 }
 545 EXPORT_SYMBOL_GPL(dlm_unregister_domain);
 546
 547 static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data)
 548 {
 549         struct dlm_query_join_request *query;
 550         enum dlm_query_join_response response;
 551         struct dlm_ctxt *dlm = NULL;
 552
 553         query = (struct dlm_query_join_request *) msg->buf;
 554
 555         mlog(0, "node %u wants to join domain %s\n", query->node_idx,
 556                   query->domain);
 557
 558         /*
 559          * If heartbeat doesn't consider the node live, tell it
 560          * to back off and try again.  This gives heartbeat a chance
 561          * to catch up.
 562          */
 563         if (!o2hb_check_node_heartbeating(query->node_idx)) {
 564                 mlog(0, "node %u is not in our live map yet\n",
 565                      query->node_idx);
 566
 567                 response = JOIN_DISALLOW;
 568                 goto respond;
 569         }
 570
 571         response = JOIN_OK_NO_MAP;
 572
 573         spin_lock(&dlm_domain_lock);
 574         dlm = __dlm_lookup_domain_full(query->domain, query->name_len);
 575         /* Once the dlm ctxt is marked as leaving then we don't want
 576          * to be put in someone's domain map.
 577          * Also, explicitly disallow joining at certain troublesome
 578          * times (ie. during recovery). */
 579         if (dlm && dlm->dlm_state != DLM_CTXT_LEAVING) {
 580                 int bit = query->node_idx;
 581                 spin_lock(&dlm->spinlock);
 582
 583                 if (dlm->dlm_state == DLM_CTXT_NEW &&
 584                     dlm->joining_node == DLM_LOCK_RES_OWNER_UNKNOWN) {
 585                         /*If this is a brand new context and we
 586                          * haven't started our join process yet, then
 587                          * the other node won the race. */
 588                         response = JOIN_OK_NO_MAP;
 589                 } else if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
 590                         /* Disallow parallel joins. */
 591                         response = JOIN_DISALLOW;
 592                 } else if (dlm->reco.state & DLM_RECO_STATE_ACTIVE) {
 593                         mlog(ML_NOTICE, "node %u trying to join, but recovery "
 594                              "is ongoing.\n", bit);
 595                         response = JOIN_DISALLOW;
 596                 } else if (test_bit(bit, dlm->recovery_map)) {
 597                         mlog(ML_NOTICE, "node %u trying to join, but it "
 598                              "still needs recovery.\n", bit);
 599                         response = JOIN_DISALLOW;
 600                 } else if (test_bit(bit, dlm->domain_map)) {
 601                         mlog(ML_NOTICE, "node %u trying to join, but it "
 602                              "is still in the domain! needs recovery?\n",
 603                              bit);
 604                         response = JOIN_DISALLOW;
 605                 } else {
 606                         /* Alright we're fully a part of this domain
 607                          * so we keep some state as to who's joining
 608                          * and indicate to him that needs to be fixed
 609                          * up. */
 610                         response = JOIN_OK;
 611                         __dlm_set_joining_node(dlm, query->node_idx);
 612                 }
 613
 614                 spin_unlock(&dlm->spinlock);
 615         }
 616         spin_unlock(&dlm_domain_lock);
 617
 618 respond:
 619         mlog(0, "We respond with %u\n", response);
 620
 621         return response;
 622 }
 623
 624 static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data)
 625 {
 626         struct dlm_assert_joined *assert;
 627         struct dlm_ctxt *dlm = NULL;
 628
 629         assert = (struct dlm_assert_joined *) msg->buf;
 630
 631         mlog(0, "node %u asserts join on domain %s\n", assert->node_idx,
 632                   assert->domain);
 633
 634         spin_lock(&dlm_domain_lock);
 635         dlm = __dlm_lookup_domain_full(assert->domain, assert->name_len);
 636         /* XXX should we consider no dlm ctxt an error? */
 637         if (dlm) {
 638                 spin_lock(&dlm->spinlock);
 639
 640                 /* Alright, this node has officially joined our
 641                  * domain. Set him in the map and clean up our
 642                  * leftover join state. */
 643                 BUG_ON(dlm->joining_node != assert->node_idx);
 644                 set_bit(assert->node_idx, dlm->domain_map);
 645                 __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
 646
 647                 __dlm_print_nodes(dlm);
 648
 649                 /* notify anything attached to the heartbeat events */
 650                 dlm_hb_event_notify_attached(dlm, assert->node_idx, 1);
 651
 652                 spin_unlock(&dlm->spinlock);
 653         }
 654         spin_unlock(&dlm_domain_lock);
 655
 656         return 0;
 657 }
 658
 659 static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data)
 660 {
 661         struct dlm_cancel_join *cancel;
 662         struct dlm_ctxt *dlm = NULL;
 663
 664         cancel = (struct dlm_cancel_join *) msg->buf;
 665
 666         mlog(0, "node %u cancels join on domain %s\n", cancel->node_idx,
 667                   cancel->domain);
 668
 669         spin_lock(&dlm_domain_lock);
 670         dlm = __dlm_lookup_domain_full(cancel->domain, cancel->name_len);
 671
 672         if (dlm) {
 673                 spin_lock(&dlm->spinlock);
 674
 675                 /* Yikes, this guy wants to cancel his join. No
 676                  * problem, we simply cleanup our join state. */
 677                 BUG_ON(dlm->joining_node != cancel->node_idx);
 678                 __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
 679
 680                 spin_unlock(&dlm->spinlock);
 681         }
 682         spin_unlock(&dlm_domain_lock);
 683
 684         return 0;
 685 }
 686
 687 static int dlm_send_one_join_cancel(struct dlm_ctxt *dlm,
 688                                     unsigned int node)
 689 {
 690         int status;
 691         struct dlm_cancel_join cancel_msg;
 692
 693         memset(&cancel_msg, 0, sizeof(cancel_msg));
 694         cancel_msg.node_idx = dlm->node_num;
 695         cancel_msg.name_len = strlen(dlm->name);
 696         memcpy(cancel_msg.domain, dlm->name, cancel_msg.name_len);
 697
 698         status = o2net_send_message(DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
 699                                     &cancel_msg, sizeof(cancel_msg), node,
 700                                     NULL);
 701         if (status < 0) {
 702                 mlog_errno(status);
 703                 goto bail;
 704         }
 705
 706 bail:
 707         return status;
 708 }
 709
 710 /* map_size should be in bytes. */
 711 static int dlm_send_join_cancels(struct dlm_ctxt *dlm,
 712                                  unsigned long *node_map,
 713                                  unsigned int map_size)
 714 {
 715         int status, tmpstat;
 716         unsigned int node;
 717
 718         if (map_size != (BITS_TO_LONGS(O2NM_MAX_NODES) *
 719                          sizeof(unsigned long))) {
 720                 mlog(ML_ERROR,
 721                      "map_size %u != BITS_TO_LONGS(O2NM_MAX_NODES) %u\n",
 722                      map_size, BITS_TO_LONGS(O2NM_MAX_NODES));
 723                 return -EINVAL;
 724         }
 725
 726         status = 0;
 727         node = -1;
 728         while ((node = find_next_bit(node_map, O2NM_MAX_NODES,
 729                                      node + 1)) < O2NM_MAX_NODES) {
 730                 if (node == dlm->node_num)
 731                         continue;
 732
 733                 tmpstat = dlm_send_one_join_cancel(dlm, node);
 734                 if (tmpstat) {
 735                         mlog(ML_ERROR, "Error return %d cancelling join on "
 736                              "node %d\n", tmpstat, node);
 737                         if (!status)
 738                                 status = tmpstat;
 739                 }
 740         }
 741
 742         if (status)
 743                 mlog_errno(status);
 744         return status;
 745 }
 746
 747 static int dlm_request_join(struct dlm_ctxt *dlm,
 748                             int node,
 749                             enum dlm_query_join_response *response)
 750 {
 751         int status, retval;
 752         struct dlm_query_join_request join_msg;
 753
 754         mlog(0, "querying node %d\n", node);
 755
 756         memset(&join_msg, 0, sizeof(join_msg));
 757         join_msg.node_idx = dlm->node_num;
 758         join_msg.name_len = strlen(dlm->name);
 759         memcpy(join_msg.domain, dlm->name, join_msg.name_len);
 760
 761         status = o2net_send_message(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY, &join_msg,
 762                                     sizeof(join_msg), node, &retval);
 763         if (status < 0 && status != -ENOPROTOOPT) {
 764                 mlog_errno(status);
 765                 goto bail;
 766         }
 767
 768         /* -ENOPROTOOPT from the net code means the other side isn't
 769             listening for our message type -- that's fine, it means
 770             his dlm isn't up, so we can consider him a 'yes' but not
 771             joined into the domain.  */
 772         if (status == -ENOPROTOOPT) {
 773                 status = 0;
 774                 *response = JOIN_OK_NO_MAP;
 775         } else if (retval == JOIN_DISALLOW ||
 776                    retval == JOIN_OK ||
 777                    retval == JOIN_OK_NO_MAP) {
 778                 *response = retval;
 779         } else {
 780                 status = -EINVAL;
 781                 mlog(ML_ERROR, "invalid response %d from node %u\n", retval,
 782                      node);
 783         }
 784
 785         mlog(0, "status %d, node %d response is %d\n", status, node,
 786                   *response);
 787
 788 bail:
 789         return status;
 790 }
 791
 792 static int dlm_send_one_join_assert(struct dlm_ctxt *dlm,
 793                                     unsigned int node)
 794 {
 795         int status;
 796         struct dlm_assert_joined assert_msg;
 797
 798         mlog(0, "Sending join assert to node %u\n", node);
 799
 800         memset(&assert_msg, 0, sizeof(assert_msg));
 801         assert_msg.node_idx = dlm->node_num;
 802         assert_msg.name_len = strlen(dlm->name);
 803         memcpy(assert_msg.domain, dlm->name, assert_msg.name_len);
 804
 805         status = o2net_send_message(DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
 806                                     &assert_msg, sizeof(assert_msg), node,
 807                                     NULL);
 808         if (status < 0)
 809                 mlog_errno(status);
 810
 811         return status;
 812 }
 813
 814 static void dlm_send_join_asserts(struct dlm_ctxt *dlm,
 815                                   unsigned long *node_map)
 816 {
 817         int status, node, live;
 818
 819         status = 0;
 820         node = -1;
 821         while ((node = find_next_bit(node_map, O2NM_MAX_NODES,
 822                                      node + 1)) < O2NM_MAX_NODES) {
 823                 if (node == dlm->node_num)
 824                         continue;
 825
 826                 do {
 827                         /* It is very important that this message be
 828                          * received so we spin until either the node
 829                          * has died or it gets the message. */
 830                         status = dlm_send_one_join_assert(dlm, node);
 831
 832                         spin_lock(&dlm->spinlock);
 833                         live = test_bit(node, dlm->live_nodes_map);
 834                         spin_unlock(&dlm->spinlock);
 835
 836                         if (status) {
 837                                 mlog(ML_ERROR, "Error return %d asserting "
 838                                      "join on node %d\n", status, node);
 839
 840                                 /* give us some time between errors... */
 841                                 if (live)
 842                                         msleep(DLM_DOMAIN_BACKOFF_MS);
 843                         }
 844                 } while (status && live);
 845         }
 846 }
 847
 848 struct domain_join_ctxt {
 849         unsigned long live_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
 850         unsigned long yes_resp_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
 851 };
 852
 853 static int dlm_should_restart_join(struct dlm_ctxt *dlm,
 854                                    struct domain_join_ctxt *ctxt,
 855                                    enum dlm_query_join_response response)
 856 {
 857         int ret;
 858
 859         if (response == JOIN_DISALLOW) {
 860                 mlog(0, "Latest response of disallow -- should restart\n");
 861                 return 1;
 862         }
 863
 864         spin_lock(&dlm->spinlock);
 865         /* For now, we restart the process if the node maps have
 866          * changed at all */
 867         ret = memcmp(ctxt->live_map, dlm->live_nodes_map,
 868                      sizeof(dlm->live_nodes_map));
 869         spin_unlock(&dlm->spinlock);
 870
 871         if (ret)
 872                 mlog(0, "Node maps changed -- should restart\n");
 873
 874         return ret;
 875 }
 876
 877 static int dlm_try_to_join_domain(struct dlm_ctxt *dlm)
 878 {
 879         int status = 0, tmpstat, node;
 880         struct domain_join_ctxt *ctxt;
 881         enum dlm_query_join_response response;
 882
 883         mlog_entry("%p", dlm);
 884
 885         ctxt = kcalloc(1, sizeof(*ctxt), GFP_KERNEL);
 886         if (!ctxt) {
 887                 status = -ENOMEM;
 888                 mlog_errno(status);
 889                 goto bail;
 890         }
 891
 892         /* group sem locking should work for us here -- we're already
 893          * registered for heartbeat events so filling this should be
 894          * atomic wrt getting those handlers called. */
 895         o2hb_fill_node_map(dlm->live_nodes_map, sizeof(dlm->live_nodes_map));
 896
 897         spin_lock(&dlm->spinlock);
 898         memcpy(ctxt->live_map, dlm->live_nodes_map, sizeof(ctxt->live_map));
 899
 900         __dlm_set_joining_node(dlm, dlm->node_num);
 901
 902         spin_unlock(&dlm->spinlock);
 903
 904         node = -1;
 905         while ((node = find_next_bit(ctxt->live_map, O2NM_MAX_NODES,
 906                                      node + 1)) < O2NM_MAX_NODES) {
 907                 if (node == dlm->node_num)
 908                         continue;
 909
 910                 status = dlm_request_join(dlm, node, &response);
 911                 if (status < 0) {
 912                         mlog_errno(status);
 913                         goto bail;
 914                 }
 915
 916                 /* Ok, either we got a response or the node doesn't have a
 917                  * dlm up. */
 918                 if (response == JOIN_OK)
 919                         set_bit(node, ctxt->yes_resp_map);
 920
 921                 if (dlm_should_restart_join(dlm, ctxt, response)) {
 922                         status = -EAGAIN;
 923                         goto bail;
 924                 }
 925         }
 926
 927         mlog(0, "Yay, done querying nodes!\n");
 928
 929         /* Yay, everyone agree's we can join the domain. My domain is
 930          * comprised of all nodes who were put in the
 931          * yes_resp_map. Copy that into our domain map and send a join
 932          * assert message to clean up everyone elses state. */
 933         spin_lock(&dlm->spinlock);
 934         memcpy(dlm->domain_map, ctxt->yes_resp_map,
 935                sizeof(ctxt->yes_resp_map));
 936         set_bit(dlm->node_num, dlm->domain_map);
 937         spin_unlock(&dlm->spinlock);
 938
 939         dlm_send_join_asserts(dlm, ctxt->yes_resp_map);
 940
 941         /* Joined state *must* be set before the joining node
 942          * information, otherwise the query_join handler may read no
 943          * current joiner but a state of NEW and tell joining nodes
 944          * we're not in the domain. */
 945         spin_lock(&dlm_domain_lock);
 946         dlm->dlm_state = DLM_CTXT_JOINED;
 947         dlm->num_joins++;
 948         spin_unlock(&dlm_domain_lock);
 949
 950 bail:
 951         spin_lock(&dlm->spinlock);
 952         __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
 953         if (!status)
 954                 __dlm_print_nodes(dlm);
 955         spin_unlock(&dlm->spinlock);
 956
 957         if (ctxt) {
 958                 /* Do we need to send a cancel message to any nodes? */
 959                 if (status < 0) {
 960                         tmpstat = dlm_send_join_cancels(dlm,
 961                                                         ctxt->yes_resp_map,
 962                                                         sizeof(ctxt->yes_resp_map));
 963                         if (tmpstat < 0)
 964                                 mlog_errno(tmpstat);
 965                 }
 966                 kfree(ctxt);
 967         }
 968
 969         mlog(0, "returning %d\n", status);
 970         return status;
 971 }
 972
 973 static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm)
 974 {
 975         o2hb_unregister_callback(&dlm->dlm_hb_up);
 976         o2hb_unregister_callback(&dlm->dlm_hb_down);
 977         o2net_unregister_handler_list(&dlm->dlm_domain_handlers);
 978 }
 979
 980 static int dlm_register_domain_handlers(struct dlm_ctxt *dlm)
 981 {
 982         int status;
 983
 984         mlog(0, "registering handlers.\n");
 985
 986         o2hb_setup_callback(&dlm->dlm_hb_down, O2HB_NODE_DOWN_CB,
 987                             dlm_hb_node_down_cb, dlm, DLM_HB_NODE_DOWN_PRI);
 988         status = o2hb_register_callback(&dlm->dlm_hb_down);
 989         if (status)
 990                 goto bail;
 991
 992         o2hb_setup_callback(&dlm->dlm_hb_up, O2HB_NODE_UP_CB,
 993                             dlm_hb_node_up_cb, dlm, DLM_HB_NODE_UP_PRI);
 994         status = o2hb_register_callback(&dlm->dlm_hb_up);
 995         if (status)
 996                 goto bail;
 997
 998         status = o2net_register_handler(DLM_MASTER_REQUEST_MSG, dlm->key,
 999                                         sizeof(struct dlm_master_request),
1000                                         dlm_master_request_handler,
1001                                         dlm, &dlm->dlm_domain_handlers);
1002         if (status)
1003                 goto bail;
1004
1005         status = o2net_register_handler(DLM_ASSERT_MASTER_MSG, dlm->key,
1006                                         sizeof(struct dlm_assert_master),
1007                                         dlm_assert_master_handler,
1008                                         dlm, &dlm->dlm_domain_handlers);
1009         if (status)
1010                 goto bail;
1011
1012         status = o2net_register_handler(DLM_CREATE_LOCK_MSG, dlm->key,
1013                                         sizeof(struct dlm_create_lock),
1014                                         dlm_create_lock_handler,
1015                                         dlm, &dlm->dlm_domain_handlers);
1016         if (status)
1017                 goto bail;
1018
1019         status = o2net_register_handler(DLM_CONVERT_LOCK_MSG, dlm->key,
1020                                         DLM_CONVERT_LOCK_MAX_LEN,
1021                                         dlm_convert_lock_handler,
1022                                         dlm, &dlm->dlm_domain_handlers);
1023         if (status)
1024                 goto bail;
1025
1026         status = o2net_register_handler(DLM_UNLOCK_LOCK_MSG, dlm->key,
1027                                         DLM_UNLOCK_LOCK_MAX_LEN,
1028                                         dlm_unlock_lock_handler,
1029                                         dlm, &dlm->dlm_domain_handlers);
1030         if (status)
1031                 goto bail;
1032
1033         status = o2net_register_handler(DLM_PROXY_AST_MSG, dlm->key,
1034                                         DLM_PROXY_AST_MAX_LEN,
1035                                         dlm_proxy_ast_handler,
1036                                         dlm, &dlm->dlm_domain_handlers);
1037         if (status)
1038                 goto bail;
1039
1040         status = o2net_register_handler(DLM_EXIT_DOMAIN_MSG, dlm->key,
1041                                         sizeof(struct dlm_exit_domain),
1042                                         dlm_exit_domain_handler,
1043                                         dlm, &dlm->dlm_domain_handlers);
1044         if (status)
1045                 goto bail;
1046
1047         status = o2net_register_handler(DLM_MIGRATE_REQUEST_MSG, dlm->key,
1048                                         sizeof(struct dlm_migrate_request),
1049                                         dlm_migrate_request_handler,
1050                                         dlm, &dlm->dlm_domain_handlers);
1051         if (status)
1052                 goto bail;
1053
1054         status = o2net_register_handler(DLM_MIG_LOCKRES_MSG, dlm->key,
1055                                         DLM_MIG_LOCKRES_MAX_LEN,
1056                                         dlm_mig_lockres_handler,
1057                                         dlm, &dlm->dlm_domain_handlers);
1058         if (status)
1059                 goto bail;
1060
1061         status = o2net_register_handler(DLM_MASTER_REQUERY_MSG, dlm->key,
1062                                         sizeof(struct dlm_master_requery),
1063                                         dlm_master_requery_handler,
1064                                         dlm, &dlm->dlm_domain_handlers);
1065         if (status)
1066                 goto bail;
1067
1068         status = o2net_register_handler(DLM_LOCK_REQUEST_MSG, dlm->key,
1069                                         sizeof(struct dlm_lock_request),
1070                                         dlm_request_all_locks_handler,
1071                                         dlm, &dlm->dlm_domain_handlers);
1072         if (status)
1073                 goto bail;
1074
1075         status = o2net_register_handler(DLM_RECO_DATA_DONE_MSG, dlm->key,
1076                                         sizeof(struct dlm_reco_data_done),
1077                                         dlm_reco_data_done_handler,
1078                                         dlm, &dlm->dlm_domain_handlers);
1079         if (status)
1080                 goto bail;
1081
1082         status = o2net_register_handler(DLM_BEGIN_RECO_MSG, dlm->key,
1083                                         sizeof(struct dlm_begin_reco),
1084                                         dlm_begin_reco_handler,
1085                                         dlm, &dlm->dlm_domain_handlers);
1086         if (status)
1087                 goto bail;
1088
1089         status = o2net_register_handler(DLM_FINALIZE_RECO_MSG, dlm->key,
1090                                         sizeof(struct dlm_finalize_reco),
1091                                         dlm_finalize_reco_handler,
1092                                         dlm, &dlm->dlm_domain_handlers);
1093         if (status)
1094                 goto bail;
1095
1096 bail:
1097         if (status)
1098                 dlm_unregister_domain_handlers(dlm);
1099
1100         return status;
1101 }
1102
1103 static int dlm_join_domain(struct dlm_ctxt *dlm)
1104 {
1105         int status;
1106
1107         BUG_ON(!dlm);
1108
1109         mlog(0, "Join domain %s\n", dlm->name);
1110
1111         status = dlm_register_domain_handlers(dlm);
1112         if (status) {
1113                 mlog_errno(status);
1114                 goto bail;
1115         }
1116
1117         status = dlm_launch_thread(dlm);
1118         if (status < 0) {
1119                 mlog_errno(status);
1120                 goto bail;
1121         }
1122
1123         status = dlm_launch_recovery_thread(dlm);
1124         if (status < 0) {
1125                 mlog_errno(status);
1126                 goto bail;
1127         }
1128
1129         do {
1130                 unsigned int backoff;
1131                 status = dlm_try_to_join_domain(dlm);
1132
1133                 /* If we're racing another node to the join, then we
1134                  * need to back off temporarily and let them
1135                  * complete. */
1136                 if (status == -EAGAIN) {
1137                         if (signal_pending(current)) {
1138                                 status = -ERESTARTSYS;
1139                                 goto bail;
1140                         }
1141
1142                         /*
1143                          * <chip> After you!
1144                          * <dale> No, after you!
1145                          * <chip> I insist!
1146                          * <dale> But you first!
1147                          * ...
1148                          */
1149                         backoff = (unsigned int)(jiffies & 0x3);
1150                         backoff *= DLM_DOMAIN_BACKOFF_MS;
1151                         mlog(0, "backoff %d\n", backoff);
1152                         msleep(backoff);
1153                 }
1154         } while (status == -EAGAIN);
1155
1156         if (status < 0) {
1157                 mlog_errno(status);
1158                 goto bail;
1159         }
1160
1161         status = 0;
1162 bail:
1163         wake_up(&dlm_domain_events);
1164
1165         if (status) {
1166                 dlm_unregister_domain_handlers(dlm);
1167                 dlm_complete_thread(dlm);
1168                 dlm_complete_recovery_thread(dlm);
1169         }
1170
1171         return status;
1172 }
1173
1174 static struct dlm_ctxt *dlm_alloc_ctxt(const char *domain,
1175                                 u32 key)
1176 {
1177         int i;
1178         struct dlm_ctxt *dlm = NULL;
1179
1180         dlm = kcalloc(1, sizeof(*dlm), GFP_KERNEL);
1181         if (!dlm) {
1182                 mlog_errno(-ENOMEM);
1183                 goto leave;
1184         }
1185
1186         dlm->name = kmalloc(strlen(domain) + 1, GFP_KERNEL);
1187         if (dlm->name == NULL) {
1188                 mlog_errno(-ENOMEM);
1189                 kfree(dlm);
1190                 dlm = NULL;
1191                 goto leave;
1192         }
1193
1194         dlm->lockres_hash = (struct hlist_head *) __get_free_page(GFP_KERNEL);
1195         if (!dlm->lockres_hash) {
1196                 mlog_errno(-ENOMEM);
1197                 kfree(dlm->name);
1198                 kfree(dlm);
1199                 dlm = NULL;
1200                 goto leave;
1201         }
1202
1203         for (i=0; i<DLM_HASH_BUCKETS; i++)
1204                 INIT_HLIST_HEAD(&dlm->lockres_hash[i]);
1205
1206         strcpy(dlm->name, domain);
1207         dlm->key = key;
1208         dlm->node_num = o2nm_this_node();
1209
1210         spin_lock_init(&dlm->spinlock);
1211         spin_lock_init(&dlm->master_lock);
1212         spin_lock_init(&dlm->ast_lock);
1213         INIT_LIST_HEAD(&dlm->list);
1214         INIT_LIST_HEAD(&dlm->dirty_list);
1215         INIT_LIST_HEAD(&dlm->reco.resources);
1216         INIT_LIST_HEAD(&dlm->reco.received);
1217         INIT_LIST_HEAD(&dlm->reco.node_data);
1218         INIT_LIST_HEAD(&dlm->purge_list);
1219         INIT_LIST_HEAD(&dlm->dlm_domain_handlers);
1220         dlm->reco.state = 0;
1221
1222         INIT_LIST_HEAD(&dlm->pending_asts);
1223         INIT_LIST_HEAD(&dlm->pending_basts);
1224
1225         mlog(0, "dlm->recovery_map=%p, &(dlm->recovery_map[0])=%p\n",
1226                   dlm->recovery_map, &(dlm->recovery_map[0]));
1227
1228         memset(dlm->recovery_map, 0, sizeof(dlm->recovery_map));
1229         memset(dlm->live_nodes_map, 0, sizeof(dlm->live_nodes_map));
1230         memset(dlm->domain_map, 0, sizeof(dlm->domain_map));
1231
1232         dlm->dlm_thread_task = NULL;
1233         dlm->dlm_reco_thread_task = NULL;
1234         init_waitqueue_head(&dlm->dlm_thread_wq);
1235         init_waitqueue_head(&dlm->dlm_reco_thread_wq);
1236         init_waitqueue_head(&dlm->reco.event);
1237         init_waitqueue_head(&dlm->ast_wq);
1238         init_waitqueue_head(&dlm->migration_wq);
1239         INIT_LIST_HEAD(&dlm->master_list);
1240         INIT_LIST_HEAD(&dlm->mle_hb_events);
1241
1242         dlm->joining_node = DLM_LOCK_RES_OWNER_UNKNOWN;
1243         init_waitqueue_head(&dlm->dlm_join_events);
1244
1245         dlm->reco.new_master = O2NM_INVALID_NODE_NUM;
1246         dlm->reco.dead_node = O2NM_INVALID_NODE_NUM;
1247         atomic_set(&dlm->local_resources, 0);
1248         atomic_set(&dlm->remote_resources, 0);
1249         atomic_set(&dlm->unknown_resources, 0);
1250
1251         spin_lock_init(&dlm->work_lock);
1252         INIT_LIST_HEAD(&dlm->work_list);
1253         INIT_WORK(&dlm->dispatched_work, dlm_dispatch_work, dlm);
1254
1255         kref_init(&dlm->dlm_refs);
1256         dlm->dlm_state = DLM_CTXT_NEW;
1257
1258         INIT_LIST_HEAD(&dlm->dlm_eviction_callbacks);
1259
1260         mlog(0, "context init: refcount %u\n",
1261                   atomic_read(&dlm->dlm_refs.refcount));
1262
1263 leave:
1264         return dlm;
1265 }
1266
1267 /*
1268  * dlm_register_domain: one-time setup per "domain"
1269  */
1270 struct dlm_ctxt * dlm_register_domain(const char *domain,
1271                                u32 key)
1272 {
1273         int ret;
1274         struct dlm_ctxt *dlm = NULL;
1275         struct dlm_ctxt *new_ctxt = NULL;
1276
1277         if (strlen(domain) > O2NM_MAX_NAME_LEN) {
1278                 ret = -ENAMETOOLONG;
1279                 mlog(ML_ERROR, "domain name length too long\n");
1280                 goto leave;
1281         }
1282
1283         if (!o2hb_check_local_node_heartbeating()) {
1284                 mlog(ML_ERROR, "the local node has not been configured, or is "
1285                      "not heartbeating\n");
1286                 ret = -EPROTO;
1287                 goto leave;
1288         }
1289
1290         mlog(0, "register called for domain \"%s\"\n", domain);
1291
1292 retry:
1293         dlm = NULL;
1294         if (signal_pending(current)) {
1295                 ret = -ERESTARTSYS;
1296                 mlog_errno(ret);
1297                 goto leave;
1298         }
1299
1300         spin_lock(&dlm_domain_lock);
1301
1302         dlm = __dlm_lookup_domain(domain);
1303         if (dlm) {
1304                 if (dlm->dlm_state != DLM_CTXT_JOINED) {
1305                         spin_unlock(&dlm_domain_lock);
1306
1307                         mlog(0, "This ctxt is not joined yet!\n");
1308                         wait_event_interruptible(dlm_domain_events,
1309                                                  dlm_wait_on_domain_helper(
1310                                                          domain));
1311                         goto retry;
1312                 }
1313
1314                 __dlm_get(dlm);
1315                 dlm->num_joins++;
1316
1317                 spin_unlock(&dlm_domain_lock);
1318
1319                 ret = 0;
1320                 goto leave;
1321         }
1322
1323         /* doesn't exist */
1324         if (!new_ctxt) {
1325                 spin_unlock(&dlm_domain_lock);
1326
1327                 new_ctxt = dlm_alloc_ctxt(domain, key);
1328                 if (new_ctxt)
1329                         goto retry;
1330
1331                 ret = -ENOMEM;
1332                 mlog_errno(ret);
1333                 goto leave;
1334         }
1335
1336         /* a little variable switch-a-roo here... */
1337         dlm = new_ctxt;
1338         new_ctxt = NULL;
1339
1340         /* add the new domain */
1341         list_add_tail(&dlm->list, &dlm_domains);
1342         spin_unlock(&dlm_domain_lock);
1343
1344         ret = dlm_join_domain(dlm);
1345         if (ret) {
1346                 mlog_errno(ret);
1347                 dlm_put(dlm);
1348                 goto leave;
1349         }
1350
1351         ret = 0;
1352 leave:
1353         if (new_ctxt)
1354                 dlm_free_ctxt_mem(new_ctxt);
1355
1356         if (ret < 0)
1357                 dlm = ERR_PTR(ret);
1358
1359         return dlm;
1360 }
1361 EXPORT_SYMBOL_GPL(dlm_register_domain);
1362
1363 static LIST_HEAD(dlm_join_handlers);
1364
1365 static void dlm_unregister_net_handlers(void)
1366 {
1367         o2net_unregister_handler_list(&dlm_join_handlers);
1368 }
1369
1370 static int dlm_register_net_handlers(void)
1371 {
1372         int status = 0;
1373
1374         status = o2net_register_handler(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY,
1375                                         sizeof(struct dlm_query_join_request),
1376                                         dlm_query_join_handler,
1377                                         NULL, &dlm_join_handlers);
1378         if (status)
1379                 goto bail;
1380
1381         status = o2net_register_handler(DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
1382                                         sizeof(struct dlm_assert_joined),
1383                                         dlm_assert_joined_handler,
1384                                         NULL, &dlm_join_handlers);
1385         if (status)
1386                 goto bail;
1387
1388         status = o2net_register_handler(DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
1389                                         sizeof(struct dlm_cancel_join),
1390                                         dlm_cancel_join_handler,
1391                                         NULL, &dlm_join_handlers);
1392
1393 bail:
1394         if (status < 0)
1395                 dlm_unregister_net_handlers();
1396
1397         return status;
1398 }
1399
1400 /* Domain eviction callback handling.
1401  *
1402  * The file system requires notification of node death *before* the
1403  * dlm completes it's recovery work, otherwise it may be able to
1404  * acquire locks on resources requiring recovery. Since the dlm can
1405  * evict a node from it's domain *before* heartbeat fires, a similar
1406  * mechanism is required. */
1407
1408 /* Eviction is not expected to happen often, so a per-domain lock is
1409  * not necessary. Eviction callbacks are allowed to sleep for short
1410  * periods of time. */
1411 static DECLARE_RWSEM(dlm_callback_sem);
1412
1413 void dlm_fire_domain_eviction_callbacks(struct dlm_ctxt *dlm,
1414                                         int node_num)
1415 {
1416         struct list_head *iter;
1417         struct dlm_eviction_cb *cb;
1418
1419         down_read(&dlm_callback_sem);
1420         list_for_each(iter, &dlm->dlm_eviction_callbacks) {
1421                 cb = list_entry(iter, struct dlm_eviction_cb, ec_item);
1422
1423                 cb->ec_func(node_num, cb->ec_data);
1424         }
1425         up_read(&dlm_callback_sem);
1426 }
1427
1428 void dlm_setup_eviction_cb(struct dlm_eviction_cb *cb,
1429                            dlm_eviction_func *f,
1430                            void *data)
1431 {
1432         INIT_LIST_HEAD(&cb->ec_item);
1433         cb->ec_func = f;
1434         cb->ec_data = data;
1435 }
1436 EXPORT_SYMBOL_GPL(dlm_setup_eviction_cb);
1437
1438 void dlm_register_eviction_cb(struct dlm_ctxt *dlm,
1439                               struct dlm_eviction_cb *cb)
1440 {
1441         down_write(&dlm_callback_sem);
1442         list_add_tail(&cb->ec_item, &dlm->dlm_eviction_callbacks);
1443         up_write(&dlm_callback_sem);
1444 }
1445 EXPORT_SYMBOL_GPL(dlm_register_eviction_cb);
1446
1447 void dlm_unregister_eviction_cb(struct dlm_eviction_cb *cb)
1448 {
1449         down_write(&dlm_callback_sem);
1450         list_del_init(&cb->ec_item);
1451         up_write(&dlm_callback_sem);
1452 }
1453 EXPORT_SYMBOL_GPL(dlm_unregister_eviction_cb);
1454
1455 static int __init dlm_init(void)
1456 {
1457         int status;
1458
1459         dlm_print_version();
1460
1461         status = dlm_init_mle_cache();
1462         if (status)
1463                 return -1;
1464
1465         status = dlm_register_net_handlers();
1466         if (status) {
1467                 dlm_destroy_mle_cache();
1468                 return -1;
1469         }
1470
1471         return 0;
1472 }
1473
1474 static void __exit dlm_exit (void)
1475 {
1476         dlm_unregister_net_handlers();
1477         dlm_destroy_mle_cache();
1478 }
1479
1480 MODULE_AUTHOR("Oracle");
1481 MODULE_LICENSE("GPL");
1482
1483 module_init(dlm_init);
1484 module_exit(dlm_exit);