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   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 "dlmdomain.h"
  45
  46 #include "dlmver.h"
  47
  48 #define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_DOMAIN)
  49 #include "cluster/masklog.h"
  50
  51 static void dlm_free_pagevec(void **vec, int pages)
  52 {
  53         while (pages--)
  54                 free_page((unsigned long)vec[pages]);
  55         kfree(vec);
  56 }
  57
  58 static void **dlm_alloc_pagevec(int pages)
  59 {
  60         void **vec = kmalloc(pages * sizeof(void *), GFP_KERNEL);
  61         int i;
  62
  63         if (!vec)
  64                 return NULL;
  65
  66         for (i = 0; i < pages; i++)
  67                 if (!(vec[i] = (void *)__get_free_page(GFP_KERNEL)))
  68                         goto out_free;
  69
  70         mlog(0, "Allocated DLM hash pagevec; %d pages (%lu expected), %lu buckets per page\n",
  71              pages, (unsigned long)DLM_HASH_PAGES,
  72              (unsigned long)DLM_BUCKETS_PER_PAGE);
  73         return vec;
  74 out_free:
  75         dlm_free_pagevec(vec, i);
  76         return NULL;
  77 }
  78
  79 /*
  80  *
  81  * spinlock lock ordering: if multiple locks are needed, obey this ordering:
  82  *    dlm_domain_lock
  83  *    struct dlm_ctxt->spinlock
  84  *    struct dlm_lock_resource->spinlock
  85  *    struct dlm_ctxt->master_lock
  86  *    struct dlm_ctxt->ast_lock
  87  *    dlm_master_list_entry->spinlock
  88  *    dlm_lock->spinlock
  89  *
  90  */
  91
  92 DEFINE_SPINLOCK(dlm_domain_lock);
  93 LIST_HEAD(dlm_domains);
  94 static DECLARE_WAIT_QUEUE_HEAD(dlm_domain_events);
  95
  96 #define DLM_DOMAIN_BACKOFF_MS 200
  97
  98 static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data);
  99 static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data);
 100 static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data);
 101 static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data);
 102
 103 static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm);
 104
 105 void __dlm_unhash_lockres(struct dlm_lock_resource *lockres)
 106 {
 107         hlist_del_init(&lockres->hash_node);
 108         dlm_lockres_put(lockres);
 109 }
 110
 111 void __dlm_insert_lockres(struct dlm_ctxt *dlm,
 112                        struct dlm_lock_resource *res)
 113 {
 114         struct hlist_head *bucket;
 115         struct qstr *q;
 116
 117         assert_spin_locked(&dlm->spinlock);
 118
 119         q = &res->lockname;
 120         bucket = dlm_lockres_hash(dlm, q->hash);
 121
 122         /* get a reference for our hashtable */
 123         dlm_lockres_get(res);
 124
 125         hlist_add_head(&res->hash_node, bucket);
 126 }
 127
 128 struct dlm_lock_resource * __dlm_lookup_lockres(struct dlm_ctxt *dlm,
 129                                                 const char *name,
 130                                                 unsigned int len,
 131                                                 unsigned int hash)
 132 {
 133         struct hlist_head *bucket;
 134         struct hlist_node *list;
 135
 136         mlog_entry("%.*s\n", len, name);
 137
 138         assert_spin_locked(&dlm->spinlock);
 139
 140         bucket = dlm_lockres_hash(dlm, hash);
 141
 142         hlist_for_each(list, bucket) {
 143                 struct dlm_lock_resource *res = hlist_entry(list,
 144                         struct dlm_lock_resource, hash_node);
 145                 if (res->lockname.name[0] != name[0])
 146                         continue;
 147                 if (unlikely(res->lockname.len != len))
 148                         continue;
 149                 if (memcmp(res->lockname.name + 1, name + 1, len - 1))
 150                         continue;
 151                 dlm_lockres_get(res);
 152                 return res;
 153         }
 154         return NULL;
 155 }
 156
 157 struct dlm_lock_resource * dlm_lookup_lockres(struct dlm_ctxt *dlm,
 158                                     const char *name,
 159                                     unsigned int len)
 160 {
 161         struct dlm_lock_resource *res;
 162         unsigned int hash = dlm_lockid_hash(name, len);
 163
 164         spin_lock(&dlm->spinlock);
 165         res = __dlm_lookup_lockres(dlm, name, len, hash);
 166         spin_unlock(&dlm->spinlock);
 167         return res;
 168 }
 169
 170 static struct dlm_ctxt * __dlm_lookup_domain_full(const char *domain, int len)
 171 {
 172         struct dlm_ctxt *tmp = NULL;
 173         struct list_head *iter;
 174
 175         assert_spin_locked(&dlm_domain_lock);
 176
 177         /* tmp->name here is always NULL terminated,
 178          * but domain may not be! */
 179         list_for_each(iter, &dlm_domains) {
 180                 tmp = list_entry (iter, struct dlm_ctxt, list);
 181                 if (strlen(tmp->name) == len &&
 182                     memcmp(tmp->name, domain, len)==0)
 183                         break;
 184                 tmp = NULL;
 185         }
 186
 187         return tmp;
 188 }
 189
 190 /* For null terminated domain strings ONLY */
 191 static struct dlm_ctxt * __dlm_lookup_domain(const char *domain)
 192 {
 193         assert_spin_locked(&dlm_domain_lock);
 194
 195         return __dlm_lookup_domain_full(domain, strlen(domain));
 196 }
 197
 198
 199 /* returns true on one of two conditions:
 200  * 1) the domain does not exist
 201  * 2) the domain exists and it's state is "joined" */
 202 static int dlm_wait_on_domain_helper(const char *domain)
 203 {
 204         int ret = 0;
 205         struct dlm_ctxt *tmp = NULL;
 206
 207         spin_lock(&dlm_domain_lock);
 208
 209         tmp = __dlm_lookup_domain(domain);
 210         if (!tmp)
 211                 ret = 1;
 212         else if (tmp->dlm_state == DLM_CTXT_JOINED)
 213                 ret = 1;
 214
 215         spin_unlock(&dlm_domain_lock);
 216         return ret;
 217 }
 218
 219 static void dlm_free_ctxt_mem(struct dlm_ctxt *dlm)
 220 {
 221         if (dlm->lockres_hash)
 222                 dlm_free_pagevec((void **)dlm->lockres_hash, DLM_HASH_PAGES);
 223
 224         if (dlm->name)
 225                 kfree(dlm->name);
 226
 227         kfree(dlm);
 228 }
 229
 230 /* A little strange - this function will be called while holding
 231  * dlm_domain_lock and is expected to be holding it on the way out. We
 232  * will however drop and reacquire it multiple times */
 233 static void dlm_ctxt_release(struct kref *kref)
 234 {
 235         struct dlm_ctxt *dlm;
 236
 237         dlm = container_of(kref, struct dlm_ctxt, dlm_refs);
 238
 239         BUG_ON(dlm->num_joins);
 240         BUG_ON(dlm->dlm_state == DLM_CTXT_JOINED);
 241
 242         /* we may still be in the list if we hit an error during join. */
 243         list_del_init(&dlm->list);
 244
 245         spin_unlock(&dlm_domain_lock);
 246
 247         mlog(0, "freeing memory from domain %s\n", dlm->name);
 248
 249         wake_up(&dlm_domain_events);
 250
 251         dlm_free_ctxt_mem(dlm);
 252
 253         spin_lock(&dlm_domain_lock);
 254 }
 255
 256 void dlm_put(struct dlm_ctxt *dlm)
 257 {
 258         spin_lock(&dlm_domain_lock);
 259         kref_put(&dlm->dlm_refs, dlm_ctxt_release);
 260         spin_unlock(&dlm_domain_lock);
 261 }
 262
 263 static void __dlm_get(struct dlm_ctxt *dlm)
 264 {
 265         kref_get(&dlm->dlm_refs);
 266 }
 267
 268 /* given a questionable reference to a dlm object, gets a reference if
 269  * it can find it in the list, otherwise returns NULL in which case
 270  * you shouldn't trust your pointer. */
 271 struct dlm_ctxt *dlm_grab(struct dlm_ctxt *dlm)
 272 {
 273         struct list_head *iter;
 274         struct dlm_ctxt *target = NULL;
 275
 276         spin_lock(&dlm_domain_lock);
 277
 278         list_for_each(iter, &dlm_domains) {
 279                 target = list_entry (iter, struct dlm_ctxt, list);
 280
 281                 if (target == dlm) {
 282                         __dlm_get(target);
 283                         break;
 284                 }
 285
 286                 target = NULL;
 287         }
 288
 289         spin_unlock(&dlm_domain_lock);
 290
 291         return target;
 292 }
 293
 294 int dlm_domain_fully_joined(struct dlm_ctxt *dlm)
 295 {
 296         int ret;
 297
 298         spin_lock(&dlm_domain_lock);
 299         ret = (dlm->dlm_state == DLM_CTXT_JOINED) ||
 300                 (dlm->dlm_state == DLM_CTXT_IN_SHUTDOWN);
 301         spin_unlock(&dlm_domain_lock);
 302
 303         return ret;
 304 }
 305
 306 static void dlm_destroy_dlm_worker(struct dlm_ctxt *dlm)
 307 {
 308         if (dlm->dlm_worker) {
 309                 flush_workqueue(dlm->dlm_worker);
 310                 destroy_workqueue(dlm->dlm_worker);
 311                 dlm->dlm_worker = NULL;
 312         }
 313 }
 314
 315 static void dlm_complete_dlm_shutdown(struct dlm_ctxt *dlm)
 316 {
 317         dlm_unregister_domain_handlers(dlm);
 318         dlm_complete_thread(dlm);
 319         dlm_complete_recovery_thread(dlm);
 320         dlm_destroy_dlm_worker(dlm);
 321
 322         /* We've left the domain. Now we can take ourselves out of the
 323          * list and allow the kref stuff to help us free the
 324          * memory. */
 325         spin_lock(&dlm_domain_lock);
 326         list_del_init(&dlm->list);
 327         spin_unlock(&dlm_domain_lock);
 328
 329         /* Wake up anyone waiting for us to remove this domain */
 330         wake_up(&dlm_domain_events);
 331 }
 332
 333 static void dlm_migrate_all_locks(struct dlm_ctxt *dlm)
 334 {
 335         int i;
 336         struct dlm_lock_resource *res;
 337
 338         mlog(0, "Migrating locks from domain %s\n", dlm->name);
 339 restart:
 340         spin_lock(&dlm->spinlock);
 341         for (i = 0; i < DLM_HASH_BUCKETS; i++) {
 342                 while (!hlist_empty(dlm_lockres_hash(dlm, i))) {
 343                         res = hlist_entry(dlm_lockres_hash(dlm, i)->first,
 344                                           struct dlm_lock_resource, hash_node);
 345                         /* need reference when manually grabbing lockres */
 346                         dlm_lockres_get(res);
 347                         /* this should unhash the lockres
 348                          * and exit with dlm->spinlock */
 349                         mlog(0, "purging res=%p\n", res);
 350                         if (dlm_lockres_is_dirty(dlm, res)) {
 351                                 /* HACK!  this should absolutely go.
 352                                  * need to figure out why some empty
 353                                  * lockreses are still marked dirty */
 354                                 mlog(ML_ERROR, "lockres %.*s dirty!\n",
 355                                      res->lockname.len, res->lockname.name);
 356
 357                                 spin_unlock(&dlm->spinlock);
 358                                 dlm_kick_thread(dlm, res);
 359                                 wait_event(dlm->ast_wq, !dlm_lockres_is_dirty(dlm, res));
 360                                 dlm_lockres_put(res);
 361                                 goto restart;
 362                         }
 363                         dlm_purge_lockres(dlm, res);
 364                         dlm_lockres_put(res);
 365                 }
 366         }
 367         spin_unlock(&dlm->spinlock);
 368
 369         mlog(0, "DONE Migrating locks from domain %s\n", dlm->name);
 370 }
 371
 372 static int dlm_no_joining_node(struct dlm_ctxt *dlm)
 373 {
 374         int ret;
 375
 376         spin_lock(&dlm->spinlock);
 377         ret = dlm->joining_node == DLM_LOCK_RES_OWNER_UNKNOWN;
 378         spin_unlock(&dlm->spinlock);
 379
 380         return ret;
 381 }
 382
 383 static void dlm_mark_domain_leaving(struct dlm_ctxt *dlm)
 384 {
 385         /* Yikes, a double spinlock! I need domain_lock for the dlm
 386          * state and the dlm spinlock for join state... Sorry! */
 387 again:
 388         spin_lock(&dlm_domain_lock);
 389         spin_lock(&dlm->spinlock);
 390
 391         if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
 392                 mlog(0, "Node %d is joining, we wait on it.\n",
 393                           dlm->joining_node);
 394                 spin_unlock(&dlm->spinlock);
 395                 spin_unlock(&dlm_domain_lock);
 396
 397                 wait_event(dlm->dlm_join_events, dlm_no_joining_node(dlm));
 398                 goto again;
 399         }
 400
 401         dlm->dlm_state = DLM_CTXT_LEAVING;
 402         spin_unlock(&dlm->spinlock);
 403         spin_unlock(&dlm_domain_lock);
 404 }
 405
 406 static void __dlm_print_nodes(struct dlm_ctxt *dlm)
 407 {
 408         int node = -1;
 409
 410         assert_spin_locked(&dlm->spinlock);
 411
 412         printk(KERN_INFO "ocfs2_dlm: Nodes in domain (\"%s\"): ", dlm->name);
 413
 414         while ((node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES,
 415                                      node + 1)) < O2NM_MAX_NODES) {
 416                 printk("%d ", node);
 417         }
 418         printk("\n");
 419 }
 420
 421 static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data)
 422 {
 423         struct dlm_ctxt *dlm = data;
 424         unsigned int node;
 425         struct dlm_exit_domain *exit_msg = (struct dlm_exit_domain *) msg->buf;
 426
 427         mlog_entry("%p %u %p", msg, len, data);
 428
 429         if (!dlm_grab(dlm))
 430                 return 0;
 431
 432         node = exit_msg->node_idx;
 433
 434         printk(KERN_INFO "ocfs2_dlm: Node %u leaves domain %s\n", node, dlm->name);
 435
 436         spin_lock(&dlm->spinlock);
 437         clear_bit(node, dlm->domain_map);
 438         __dlm_print_nodes(dlm);
 439
 440         /* notify anything attached to the heartbeat events */
 441         dlm_hb_event_notify_attached(dlm, node, 0);
 442
 443         spin_unlock(&dlm->spinlock);
 444
 445         dlm_put(dlm);
 446
 447         return 0;
 448 }
 449
 450 static int dlm_send_one_domain_exit(struct dlm_ctxt *dlm,
 451                                     unsigned int node)
 452 {
 453         int status;
 454         struct dlm_exit_domain leave_msg;
 455
 456         mlog(0, "Asking node %u if we can leave the domain %s me = %u\n",
 457                   node, dlm->name, dlm->node_num);
 458
 459         memset(&leave_msg, 0, sizeof(leave_msg));
 460         leave_msg.node_idx = dlm->node_num;
 461
 462         status = o2net_send_message(DLM_EXIT_DOMAIN_MSG, dlm->key,
 463                                     &leave_msg, sizeof(leave_msg), node,
 464                                     NULL);
 465
 466         mlog(0, "status return %d from o2net_send_message\n", status);
 467
 468         return status;
 469 }
 470
 471
 472 static void dlm_leave_domain(struct dlm_ctxt *dlm)
 473 {
 474         int node, clear_node, status;
 475
 476         /* At this point we've migrated away all our locks and won't
 477          * accept mastership of new ones. The dlm is responsible for
 478          * almost nothing now. We make sure not to confuse any joining
 479          * nodes and then commence shutdown procedure. */
 480
 481         spin_lock(&dlm->spinlock);
 482         /* Clear ourselves from the domain map */
 483         clear_bit(dlm->node_num, dlm->domain_map);
 484         while ((node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES,
 485                                      0)) < O2NM_MAX_NODES) {
 486                 /* Drop the dlm spinlock. This is safe wrt the domain_map.
 487                  * -nodes cannot be added now as the
 488                  *   query_join_handlers knows to respond with OK_NO_MAP
 489                  * -we catch the right network errors if a node is
 490                  *   removed from the map while we're sending him the
 491                  *   exit message. */
 492                 spin_unlock(&dlm->spinlock);
 493
 494                 clear_node = 1;
 495
 496                 status = dlm_send_one_domain_exit(dlm, node);
 497                 if (status < 0 &&
 498                     status != -ENOPROTOOPT &&
 499                     status != -ENOTCONN) {
 500                         mlog(ML_NOTICE, "Error %d sending domain exit message "
 501                              "to node %d\n", status, node);
 502
 503                         /* Not sure what to do here but lets sleep for
 504                          * a bit in case this was a transient
 505                          * error... */
 506                         msleep(DLM_DOMAIN_BACKOFF_MS);
 507                         clear_node = 0;
 508                 }
 509
 510                 spin_lock(&dlm->spinlock);
 511                 /* If we're not clearing the node bit then we intend
 512                  * to loop back around to try again. */
 513                 if (clear_node)
 514                         clear_bit(node, dlm->domain_map);
 515         }
 516         spin_unlock(&dlm->spinlock);
 517 }
 518
 519 int dlm_joined(struct dlm_ctxt *dlm)
 520 {
 521         int ret = 0;
 522
 523         spin_lock(&dlm_domain_lock);
 524
 525         if (dlm->dlm_state == DLM_CTXT_JOINED)
 526                 ret = 1;
 527
 528         spin_unlock(&dlm_domain_lock);
 529
 530         return ret;
 531 }
 532
 533 int dlm_shutting_down(struct dlm_ctxt *dlm)
 534 {
 535         int ret = 0;
 536
 537         spin_lock(&dlm_domain_lock);
 538
 539         if (dlm->dlm_state == DLM_CTXT_IN_SHUTDOWN)
 540                 ret = 1;
 541
 542         spin_unlock(&dlm_domain_lock);
 543
 544         return ret;
 545 }
 546
 547 void dlm_unregister_domain(struct dlm_ctxt *dlm)
 548 {
 549         int leave = 0;
 550
 551         spin_lock(&dlm_domain_lock);
 552         BUG_ON(dlm->dlm_state != DLM_CTXT_JOINED);
 553         BUG_ON(!dlm->num_joins);
 554
 555         dlm->num_joins--;
 556         if (!dlm->num_joins) {
 557                 /* We mark it "in shutdown" now so new register
 558                  * requests wait until we've completely left the
 559                  * domain. Don't use DLM_CTXT_LEAVING yet as we still
 560                  * want new domain joins to communicate with us at
 561                  * least until we've completed migration of our
 562                  * resources. */
 563                 dlm->dlm_state = DLM_CTXT_IN_SHUTDOWN;
 564                 leave = 1;
 565         }
 566         spin_unlock(&dlm_domain_lock);
 567
 568         if (leave) {
 569                 mlog(0, "shutting down domain %s\n", dlm->name);
 570
 571                 /* We changed dlm state, notify the thread */
 572                 dlm_kick_thread(dlm, NULL);
 573
 574                 dlm_migrate_all_locks(dlm);
 575                 dlm_mark_domain_leaving(dlm);
 576                 dlm_leave_domain(dlm);
 577                 dlm_complete_dlm_shutdown(dlm);
 578         }
 579         dlm_put(dlm);
 580 }
 581 EXPORT_SYMBOL_GPL(dlm_unregister_domain);
 582
 583 static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data)
 584 {
 585         struct dlm_query_join_request *query;
 586         enum dlm_query_join_response response;
 587         struct dlm_ctxt *dlm = NULL;
 588
 589         query = (struct dlm_query_join_request *) msg->buf;
 590
 591         mlog(0, "node %u wants to join domain %s\n", query->node_idx,
 592                   query->domain);
 593
 594         /*
 595          * If heartbeat doesn't consider the node live, tell it
 596          * to back off and try again.  This gives heartbeat a chance
 597          * to catch up.
 598          */
 599         if (!o2hb_check_node_heartbeating(query->node_idx)) {
 600                 mlog(0, "node %u is not in our live map yet\n",
 601                      query->node_idx);
 602
 603                 response = JOIN_DISALLOW;
 604                 goto respond;
 605         }
 606
 607         response = JOIN_OK_NO_MAP;
 608
 609         spin_lock(&dlm_domain_lock);
 610         dlm = __dlm_lookup_domain_full(query->domain, query->name_len);
 611         /* Once the dlm ctxt is marked as leaving then we don't want
 612          * to be put in someone's domain map.
 613          * Also, explicitly disallow joining at certain troublesome
 614          * times (ie. during recovery). */
 615         if (dlm && dlm->dlm_state != DLM_CTXT_LEAVING) {
 616                 int bit = query->node_idx;
 617                 spin_lock(&dlm->spinlock);
 618
 619                 if (dlm->dlm_state == DLM_CTXT_NEW &&
 620                     dlm->joining_node == DLM_LOCK_RES_OWNER_UNKNOWN) {
 621                         /*If this is a brand new context and we
 622                          * haven't started our join process yet, then
 623                          * the other node won the race. */
 624                         response = JOIN_OK_NO_MAP;
 625                 } else if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
 626                         /* Disallow parallel joins. */
 627                         response = JOIN_DISALLOW;
 628                 } else if (dlm->reco.state & DLM_RECO_STATE_ACTIVE) {
 629                         mlog(ML_NOTICE, "node %u trying to join, but recovery "
 630                              "is ongoing.\n", bit);
 631                         response = JOIN_DISALLOW;
 632                 } else if (test_bit(bit, dlm->recovery_map)) {
 633                         mlog(ML_NOTICE, "node %u trying to join, but it "
 634                              "still needs recovery.\n", bit);
 635                         response = JOIN_DISALLOW;
 636                 } else if (test_bit(bit, dlm->domain_map)) {
 637                         mlog(ML_NOTICE, "node %u trying to join, but it "
 638                              "is still in the domain! needs recovery?\n",
 639                              bit);
 640                         response = JOIN_DISALLOW;
 641                 } else {
 642                         /* Alright we're fully a part of this domain
 643                          * so we keep some state as to who's joining
 644                          * and indicate to him that needs to be fixed
 645                          * up. */
 646                         response = JOIN_OK;
 647                         __dlm_set_joining_node(dlm, query->node_idx);
 648                 }
 649
 650                 spin_unlock(&dlm->spinlock);
 651         }
 652         spin_unlock(&dlm_domain_lock);
 653
 654 respond:
 655         mlog(0, "We respond with %u\n", response);
 656
 657         return response;
 658 }
 659
 660 static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data)
 661 {
 662         struct dlm_assert_joined *assert;
 663         struct dlm_ctxt *dlm = NULL;
 664
 665         assert = (struct dlm_assert_joined *) msg->buf;
 666
 667         mlog(0, "node %u asserts join on domain %s\n", assert->node_idx,
 668                   assert->domain);
 669
 670         spin_lock(&dlm_domain_lock);
 671         dlm = __dlm_lookup_domain_full(assert->domain, assert->name_len);
 672         /* XXX should we consider no dlm ctxt an error? */
 673         if (dlm) {
 674                 spin_lock(&dlm->spinlock);
 675
 676                 /* Alright, this node has officially joined our
 677                  * domain. Set him in the map and clean up our
 678                  * leftover join state. */
 679                 BUG_ON(dlm->joining_node != assert->node_idx);
 680                 set_bit(assert->node_idx, dlm->domain_map);
 681                 __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
 682
 683                 printk(KERN_INFO "ocfs2_dlm: Node %u joins domain %s\n",
 684                        assert->node_idx, dlm->name);
 685                 __dlm_print_nodes(dlm);
 686
 687                 /* notify anything attached to the heartbeat events */
 688                 dlm_hb_event_notify_attached(dlm, assert->node_idx, 1);
 689
 690                 spin_unlock(&dlm->spinlock);
 691         }
 692         spin_unlock(&dlm_domain_lock);
 693
 694         return 0;
 695 }
 696
 697 static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data)
 698 {
 699         struct dlm_cancel_join *cancel;
 700         struct dlm_ctxt *dlm = NULL;
 701
 702         cancel = (struct dlm_cancel_join *) msg->buf;
 703
 704         mlog(0, "node %u cancels join on domain %s\n", cancel->node_idx,
 705                   cancel->domain);
 706
 707         spin_lock(&dlm_domain_lock);
 708         dlm = __dlm_lookup_domain_full(cancel->domain, cancel->name_len);
 709
 710         if (dlm) {
 711                 spin_lock(&dlm->spinlock);
 712
 713                 /* Yikes, this guy wants to cancel his join. No
 714                  * problem, we simply cleanup our join state. */
 715                 BUG_ON(dlm->joining_node != cancel->node_idx);
 716                 __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
 717
 718                 spin_unlock(&dlm->spinlock);
 719         }
 720         spin_unlock(&dlm_domain_lock);
 721
 722         return 0;
 723 }
 724
 725 static int dlm_send_one_join_cancel(struct dlm_ctxt *dlm,
 726                                     unsigned int node)
 727 {
 728         int status;
 729         struct dlm_cancel_join cancel_msg;
 730
 731         memset(&cancel_msg, 0, sizeof(cancel_msg));
 732         cancel_msg.node_idx = dlm->node_num;
 733         cancel_msg.name_len = strlen(dlm->name);
 734         memcpy(cancel_msg.domain, dlm->name, cancel_msg.name_len);
 735
 736         status = o2net_send_message(DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
 737                                     &cancel_msg, sizeof(cancel_msg), node,
 738                                     NULL);
 739         if (status < 0) {
 740                 mlog_errno(status);
 741                 goto bail;
 742         }
 743
 744 bail:
 745         return status;
 746 }
 747
 748 /* map_size should be in bytes. */
 749 static int dlm_send_join_cancels(struct dlm_ctxt *dlm,
 750                                  unsigned long *node_map,
 751                                  unsigned int map_size)
 752 {
 753         int status, tmpstat;
 754         unsigned int node;
 755
 756         if (map_size != (BITS_TO_LONGS(O2NM_MAX_NODES) *
 757                          sizeof(unsigned long))) {
 758                 mlog(ML_ERROR,
 759                      "map_size %u != BITS_TO_LONGS(O2NM_MAX_NODES) %u\n",
 760                      map_size, BITS_TO_LONGS(O2NM_MAX_NODES));
 761                 return -EINVAL;
 762         }
 763
 764         status = 0;
 765         node = -1;
 766         while ((node = find_next_bit(node_map, O2NM_MAX_NODES,
 767                                      node + 1)) < O2NM_MAX_NODES) {
 768                 if (node == dlm->node_num)
 769                         continue;
 770
 771                 tmpstat = dlm_send_one_join_cancel(dlm, node);
 772                 if (tmpstat) {
 773                         mlog(ML_ERROR, "Error return %d cancelling join on "
 774                              "node %d\n", tmpstat, node);
 775                         if (!status)
 776                                 status = tmpstat;
 777                 }
 778         }
 779
 780         if (status)
 781                 mlog_errno(status);
 782         return status;
 783 }
 784
 785 static int dlm_request_join(struct dlm_ctxt *dlm,
 786                             int node,
 787                             enum dlm_query_join_response *response)
 788 {
 789         int status, retval;
 790         struct dlm_query_join_request join_msg;
 791
 792         mlog(0, "querying node %d\n", node);
 793
 794         memset(&join_msg, 0, sizeof(join_msg));
 795         join_msg.node_idx = dlm->node_num;
 796         join_msg.name_len = strlen(dlm->name);
 797         memcpy(join_msg.domain, dlm->name, join_msg.name_len);
 798
 799         status = o2net_send_message(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY, &join_msg,
 800                                     sizeof(join_msg), node, &retval);
 801         if (status < 0 && status != -ENOPROTOOPT) {
 802                 mlog_errno(status);
 803                 goto bail;
 804         }
 805
 806         /* -ENOPROTOOPT from the net code means the other side isn't
 807             listening for our message type -- that's fine, it means
 808             his dlm isn't up, so we can consider him a 'yes' but not
 809             joined into the domain.  */
 810         if (status == -ENOPROTOOPT) {
 811                 status = 0;
 812                 *response = JOIN_OK_NO_MAP;
 813         } else if (retval == JOIN_DISALLOW ||
 814                    retval == JOIN_OK ||
 815                    retval == JOIN_OK_NO_MAP) {
 816                 *response = retval;
 817         } else {
 818                 status = -EINVAL;
 819                 mlog(ML_ERROR, "invalid response %d from node %u\n", retval,
 820                      node);
 821         }
 822
 823         mlog(0, "status %d, node %d response is %d\n", status, node,
 824                   *response);
 825
 826 bail:
 827         return status;
 828 }
 829
 830 static int dlm_send_one_join_assert(struct dlm_ctxt *dlm,
 831                                     unsigned int node)
 832 {
 833         int status;
 834         struct dlm_assert_joined assert_msg;
 835
 836         mlog(0, "Sending join assert to node %u\n", node);
 837
 838         memset(&assert_msg, 0, sizeof(assert_msg));
 839         assert_msg.node_idx = dlm->node_num;
 840         assert_msg.name_len = strlen(dlm->name);
 841         memcpy(assert_msg.domain, dlm->name, assert_msg.name_len);
 842
 843         status = o2net_send_message(DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
 844                                     &assert_msg, sizeof(assert_msg), node,
 845                                     NULL);
 846         if (status < 0)
 847                 mlog_errno(status);
 848
 849         return status;
 850 }
 851
 852 static void dlm_send_join_asserts(struct dlm_ctxt *dlm,
 853                                   unsigned long *node_map)
 854 {
 855         int status, node, live;
 856
 857         status = 0;
 858         node = -1;
 859         while ((node = find_next_bit(node_map, O2NM_MAX_NODES,
 860                                      node + 1)) < O2NM_MAX_NODES) {
 861                 if (node == dlm->node_num)
 862                         continue;
 863
 864                 do {
 865                         /* It is very important that this message be
 866                          * received so we spin until either the node
 867                          * has died or it gets the message. */
 868                         status = dlm_send_one_join_assert(dlm, node);
 869
 870                         spin_lock(&dlm->spinlock);
 871                         live = test_bit(node, dlm->live_nodes_map);
 872                         spin_unlock(&dlm->spinlock);
 873
 874                         if (status) {
 875                                 mlog(ML_ERROR, "Error return %d asserting "
 876                                      "join on node %d\n", status, node);
 877
 878                                 /* give us some time between errors... */
 879                                 if (live)
 880                                         msleep(DLM_DOMAIN_BACKOFF_MS);
 881                         }
 882                 } while (status && live);
 883         }
 884 }
 885
 886 struct domain_join_ctxt {
 887         unsigned long live_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
 888         unsigned long yes_resp_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
 889 };
 890
 891 static int dlm_should_restart_join(struct dlm_ctxt *dlm,
 892                                    struct domain_join_ctxt *ctxt,
 893                                    enum dlm_query_join_response response)
 894 {
 895         int ret;
 896
 897         if (response == JOIN_DISALLOW) {
 898                 mlog(0, "Latest response of disallow -- should restart\n");
 899                 return 1;
 900         }
 901
 902         spin_lock(&dlm->spinlock);
 903         /* For now, we restart the process if the node maps have
 904          * changed at all */
 905         ret = memcmp(ctxt->live_map, dlm->live_nodes_map,
 906                      sizeof(dlm->live_nodes_map));
 907         spin_unlock(&dlm->spinlock);
 908
 909         if (ret)
 910                 mlog(0, "Node maps changed -- should restart\n");
 911
 912         return ret;
 913 }
 914
 915 static int dlm_try_to_join_domain(struct dlm_ctxt *dlm)
 916 {
 917         int status = 0, tmpstat, node;
 918         struct domain_join_ctxt *ctxt;
 919         enum dlm_query_join_response response;
 920
 921         mlog_entry("%p", dlm);
 922
 923         ctxt = kcalloc(1, sizeof(*ctxt), GFP_KERNEL);
 924         if (!ctxt) {
 925                 status = -ENOMEM;
 926                 mlog_errno(status);
 927                 goto bail;
 928         }
 929
 930         /* group sem locking should work for us here -- we're already
 931          * registered for heartbeat events so filling this should be
 932          * atomic wrt getting those handlers called. */
 933         o2hb_fill_node_map(dlm->live_nodes_map, sizeof(dlm->live_nodes_map));
 934
 935         spin_lock(&dlm->spinlock);
 936         memcpy(ctxt->live_map, dlm->live_nodes_map, sizeof(ctxt->live_map));
 937
 938         __dlm_set_joining_node(dlm, dlm->node_num);
 939
 940         spin_unlock(&dlm->spinlock);
 941
 942         node = -1;
 943         while ((node = find_next_bit(ctxt->live_map, O2NM_MAX_NODES,
 944                                      node + 1)) < O2NM_MAX_NODES) {
 945                 if (node == dlm->node_num)
 946                         continue;
 947
 948                 status = dlm_request_join(dlm, node, &response);
 949                 if (status < 0) {
 950                         mlog_errno(status);
 951                         goto bail;
 952                 }
 953
 954                 /* Ok, either we got a response or the node doesn't have a
 955                  * dlm up. */
 956                 if (response == JOIN_OK)
 957                         set_bit(node, ctxt->yes_resp_map);
 958
 959                 if (dlm_should_restart_join(dlm, ctxt, response)) {
 960                         status = -EAGAIN;
 961                         goto bail;
 962                 }
 963         }
 964
 965         mlog(0, "Yay, done querying nodes!\n");
 966
 967         /* Yay, everyone agree's we can join the domain. My domain is
 968          * comprised of all nodes who were put in the
 969          * yes_resp_map. Copy that into our domain map and send a join
 970          * assert message to clean up everyone elses state. */
 971         spin_lock(&dlm->spinlock);
 972         memcpy(dlm->domain_map, ctxt->yes_resp_map,
 973                sizeof(ctxt->yes_resp_map));
 974         set_bit(dlm->node_num, dlm->domain_map);
 975         spin_unlock(&dlm->spinlock);
 976
 977         dlm_send_join_asserts(dlm, ctxt->yes_resp_map);
 978
 979         /* Joined state *must* be set before the joining node
 980          * information, otherwise the query_join handler may read no
 981          * current joiner but a state of NEW and tell joining nodes
 982          * we're not in the domain. */
 983         spin_lock(&dlm_domain_lock);
 984         dlm->dlm_state = DLM_CTXT_JOINED;
 985         dlm->num_joins++;
 986         spin_unlock(&dlm_domain_lock);
 987
 988 bail:
 989         spin_lock(&dlm->spinlock);
 990         __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
 991         if (!status)
 992                 __dlm_print_nodes(dlm);
 993         spin_unlock(&dlm->spinlock);
 994
 995         if (ctxt) {
 996                 /* Do we need to send a cancel message to any nodes? */
 997                 if (status < 0) {
 998                         tmpstat = dlm_send_join_cancels(dlm,
 999                                                         ctxt->yes_resp_map,
1000                                                         sizeof(ctxt->yes_resp_map));
1001                         if (tmpstat < 0)
1002                                 mlog_errno(tmpstat);
1003                 }
1004                 kfree(ctxt);
1005         }
1006
1007         mlog(0, "returning %d\n", status);
1008         return status;
1009 }
1010
1011 static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm)
1012 {
1013         o2hb_unregister_callback(&dlm->dlm_hb_up);
1014         o2hb_unregister_callback(&dlm->dlm_hb_down);
1015         o2net_unregister_handler_list(&dlm->dlm_domain_handlers);
1016 }
1017
1018 static int dlm_register_domain_handlers(struct dlm_ctxt *dlm)
1019 {
1020         int status;
1021
1022         mlog(0, "registering handlers.\n");
1023
1024         o2hb_setup_callback(&dlm->dlm_hb_down, O2HB_NODE_DOWN_CB,
1025                             dlm_hb_node_down_cb, dlm, DLM_HB_NODE_DOWN_PRI);
1026         status = o2hb_register_callback(&dlm->dlm_hb_down);
1027         if (status)
1028                 goto bail;
1029
1030         o2hb_setup_callback(&dlm->dlm_hb_up, O2HB_NODE_UP_CB,
1031                             dlm_hb_node_up_cb, dlm, DLM_HB_NODE_UP_PRI);
1032         status = o2hb_register_callback(&dlm->dlm_hb_up);
1033         if (status)
1034                 goto bail;
1035
1036         status = o2net_register_handler(DLM_MASTER_REQUEST_MSG, dlm->key,
1037                                         sizeof(struct dlm_master_request),
1038                                         dlm_master_request_handler,
1039                                         dlm, &dlm->dlm_domain_handlers);
1040         if (status)
1041                 goto bail;
1042
1043         status = o2net_register_handler(DLM_ASSERT_MASTER_MSG, dlm->key,
1044                                         sizeof(struct dlm_assert_master),
1045                                         dlm_assert_master_handler,
1046                                         dlm, &dlm->dlm_domain_handlers);
1047         if (status)
1048                 goto bail;
1049
1050         status = o2net_register_handler(DLM_CREATE_LOCK_MSG, dlm->key,
1051                                         sizeof(struct dlm_create_lock),
1052                                         dlm_create_lock_handler,
1053                                         dlm, &dlm->dlm_domain_handlers);
1054         if (status)
1055                 goto bail;
1056
1057         status = o2net_register_handler(DLM_CONVERT_LOCK_MSG, dlm->key,
1058                                         DLM_CONVERT_LOCK_MAX_LEN,
1059                                         dlm_convert_lock_handler,
1060                                         dlm, &dlm->dlm_domain_handlers);
1061         if (status)
1062                 goto bail;
1063
1064         status = o2net_register_handler(DLM_UNLOCK_LOCK_MSG, dlm->key,
1065                                         DLM_UNLOCK_LOCK_MAX_LEN,
1066                                         dlm_unlock_lock_handler,
1067                                         dlm, &dlm->dlm_domain_handlers);
1068         if (status)
1069                 goto bail;
1070
1071         status = o2net_register_handler(DLM_PROXY_AST_MSG, dlm->key,
1072                                         DLM_PROXY_AST_MAX_LEN,
1073                                         dlm_proxy_ast_handler,
1074                                         dlm, &dlm->dlm_domain_handlers);
1075         if (status)
1076                 goto bail;
1077
1078         status = o2net_register_handler(DLM_EXIT_DOMAIN_MSG, dlm->key,
1079                                         sizeof(struct dlm_exit_domain),
1080                                         dlm_exit_domain_handler,
1081                                         dlm, &dlm->dlm_domain_handlers);
1082         if (status)
1083                 goto bail;
1084
1085         status = o2net_register_handler(DLM_MIGRATE_REQUEST_MSG, dlm->key,
1086                                         sizeof(struct dlm_migrate_request),
1087                                         dlm_migrate_request_handler,
1088                                         dlm, &dlm->dlm_domain_handlers);
1089         if (status)
1090                 goto bail;
1091
1092         status = o2net_register_handler(DLM_MIG_LOCKRES_MSG, dlm->key,
1093                                         DLM_MIG_LOCKRES_MAX_LEN,
1094                                         dlm_mig_lockres_handler,
1095                                         dlm, &dlm->dlm_domain_handlers);
1096         if (status)
1097                 goto bail;
1098
1099         status = o2net_register_handler(DLM_MASTER_REQUERY_MSG, dlm->key,
1100                                         sizeof(struct dlm_master_requery),
1101                                         dlm_master_requery_handler,
1102                                         dlm, &dlm->dlm_domain_handlers);
1103         if (status)
1104                 goto bail;
1105
1106         status = o2net_register_handler(DLM_LOCK_REQUEST_MSG, dlm->key,
1107                                         sizeof(struct dlm_lock_request),
1108                                         dlm_request_all_locks_handler,
1109                                         dlm, &dlm->dlm_domain_handlers);
1110         if (status)
1111                 goto bail;
1112
1113         status = o2net_register_handler(DLM_RECO_DATA_DONE_MSG, dlm->key,
1114                                         sizeof(struct dlm_reco_data_done),
1115                                         dlm_reco_data_done_handler,
1116                                         dlm, &dlm->dlm_domain_handlers);
1117         if (status)
1118                 goto bail;
1119
1120         status = o2net_register_handler(DLM_BEGIN_RECO_MSG, dlm->key,
1121                                         sizeof(struct dlm_begin_reco),
1122                                         dlm_begin_reco_handler,
1123                                         dlm, &dlm->dlm_domain_handlers);
1124         if (status)
1125                 goto bail;
1126
1127         status = o2net_register_handler(DLM_FINALIZE_RECO_MSG, dlm->key,
1128                                         sizeof(struct dlm_finalize_reco),
1129                                         dlm_finalize_reco_handler,
1130                                         dlm, &dlm->dlm_domain_handlers);
1131         if (status)
1132                 goto bail;
1133
1134 bail:
1135         if (status)
1136                 dlm_unregister_domain_handlers(dlm);
1137
1138         return status;
1139 }
1140
1141 static int dlm_join_domain(struct dlm_ctxt *dlm)
1142 {
1143         int status;
1144
1145         BUG_ON(!dlm);
1146
1147         mlog(0, "Join domain %s\n", dlm->name);
1148
1149         status = dlm_register_domain_handlers(dlm);
1150         if (status) {
1151                 mlog_errno(status);
1152                 goto bail;
1153         }
1154
1155         status = dlm_launch_thread(dlm);
1156         if (status < 0) {
1157                 mlog_errno(status);
1158                 goto bail;
1159         }
1160
1161         status = dlm_launch_recovery_thread(dlm);
1162         if (status < 0) {
1163                 mlog_errno(status);
1164                 goto bail;
1165         }
1166
1167         dlm->dlm_worker = create_singlethread_workqueue("dlm_wq");
1168         if (!dlm->dlm_worker) {
1169                 status = -ENOMEM;
1170                 mlog_errno(status);
1171                 goto bail;
1172         }
1173
1174         do {
1175                 unsigned int backoff;
1176                 status = dlm_try_to_join_domain(dlm);
1177
1178                 /* If we're racing another node to the join, then we
1179                  * need to back off temporarily and let them
1180                  * complete. */
1181                 if (status == -EAGAIN) {
1182                         if (signal_pending(current)) {
1183                                 status = -ERESTARTSYS;
1184                                 goto bail;
1185                         }
1186
1187                         /*
1188                          * <chip> After you!
1189                          * <dale> No, after you!
1190                          * <chip> I insist!
1191                          * <dale> But you first!
1192                          * ...
1193                          */
1194                         backoff = (unsigned int)(jiffies & 0x3);
1195                         backoff *= DLM_DOMAIN_BACKOFF_MS;
1196                         mlog(0, "backoff %d\n", backoff);
1197                         msleep(backoff);
1198                 }
1199         } while (status == -EAGAIN);
1200
1201         if (status < 0) {
1202                 mlog_errno(status);
1203                 goto bail;
1204         }
1205
1206         status = 0;
1207 bail:
1208         wake_up(&dlm_domain_events);
1209
1210         if (status) {
1211                 dlm_unregister_domain_handlers(dlm);
1212                 dlm_complete_thread(dlm);
1213                 dlm_complete_recovery_thread(dlm);
1214                 dlm_destroy_dlm_worker(dlm);
1215         }
1216
1217         return status;
1218 }
1219
1220 static struct dlm_ctxt *dlm_alloc_ctxt(const char *domain,
1221                                 u32 key)
1222 {
1223         int i;
1224         struct dlm_ctxt *dlm = NULL;
1225
1226         dlm = kcalloc(1, sizeof(*dlm), GFP_KERNEL);
1227         if (!dlm) {
1228                 mlog_errno(-ENOMEM);
1229                 goto leave;
1230         }
1231
1232         dlm->name = kmalloc(strlen(domain) + 1, GFP_KERNEL);
1233         if (dlm->name == NULL) {
1234                 mlog_errno(-ENOMEM);
1235                 kfree(dlm);
1236                 dlm = NULL;
1237                 goto leave;
1238         }
1239
1240         dlm->lockres_hash = (struct hlist_head **)dlm_alloc_pagevec(DLM_HASH_PAGES);
1241         if (!dlm->lockres_hash) {
1242                 mlog_errno(-ENOMEM);
1243                 kfree(dlm->name);
1244                 kfree(dlm);
1245                 dlm = NULL;
1246                 goto leave;
1247         }
1248
1249         for (i = 0; i < DLM_HASH_BUCKETS; i++)
1250                 INIT_HLIST_HEAD(dlm_lockres_hash(dlm, i));
1251
1252         strcpy(dlm->name, domain);
1253         dlm->key = key;
1254         dlm->node_num = o2nm_this_node();
1255
1256         spin_lock_init(&dlm->spinlock);
1257         spin_lock_init(&dlm->master_lock);
1258         spin_lock_init(&dlm->ast_lock);
1259         INIT_LIST_HEAD(&dlm->list);
1260         INIT_LIST_HEAD(&dlm->dirty_list);
1261         INIT_LIST_HEAD(&dlm->reco.resources);
1262         INIT_LIST_HEAD(&dlm->reco.received);
1263         INIT_LIST_HEAD(&dlm->reco.node_data);
1264         INIT_LIST_HEAD(&dlm->purge_list);
1265         INIT_LIST_HEAD(&dlm->dlm_domain_handlers);
1266         dlm->reco.state = 0;
1267
1268         INIT_LIST_HEAD(&dlm->pending_asts);
1269         INIT_LIST_HEAD(&dlm->pending_basts);
1270
1271         mlog(0, "dlm->recovery_map=%p, &(dlm->recovery_map[0])=%p\n",
1272                   dlm->recovery_map, &(dlm->recovery_map[0]));
1273
1274         memset(dlm->recovery_map, 0, sizeof(dlm->recovery_map));
1275         memset(dlm->live_nodes_map, 0, sizeof(dlm->live_nodes_map));
1276         memset(dlm->domain_map, 0, sizeof(dlm->domain_map));
1277
1278         dlm->dlm_thread_task = NULL;
1279         dlm->dlm_reco_thread_task = NULL;
1280         dlm->dlm_worker = NULL;
1281         init_waitqueue_head(&dlm->dlm_thread_wq);
1282         init_waitqueue_head(&dlm->dlm_reco_thread_wq);
1283         init_waitqueue_head(&dlm->reco.event);
1284         init_waitqueue_head(&dlm->ast_wq);
1285         init_waitqueue_head(&dlm->migration_wq);
1286         INIT_LIST_HEAD(&dlm->master_list);
1287         INIT_LIST_HEAD(&dlm->mle_hb_events);
1288
1289         dlm->joining_node = DLM_LOCK_RES_OWNER_UNKNOWN;
1290         init_waitqueue_head(&dlm->dlm_join_events);
1291
1292         dlm->reco.new_master = O2NM_INVALID_NODE_NUM;
1293         dlm->reco.dead_node = O2NM_INVALID_NODE_NUM;
1294         atomic_set(&dlm->local_resources, 0);
1295         atomic_set(&dlm->remote_resources, 0);
1296         atomic_set(&dlm->unknown_resources, 0);
1297
1298         spin_lock_init(&dlm->work_lock);
1299         INIT_LIST_HEAD(&dlm->work_list);
1300         INIT_WORK(&dlm->dispatched_work, dlm_dispatch_work);
1301
1302         kref_init(&dlm->dlm_refs);
1303         dlm->dlm_state = DLM_CTXT_NEW;
1304
1305         INIT_LIST_HEAD(&dlm->dlm_eviction_callbacks);
1306
1307         mlog(0, "context init: refcount %u\n",
1308                   atomic_read(&dlm->dlm_refs.refcount));
1309
1310 leave:
1311         return dlm;
1312 }
1313
1314 /*
1315  * dlm_register_domain: one-time setup per "domain"
1316  */
1317 struct dlm_ctxt * dlm_register_domain(const char *domain,
1318                                u32 key)
1319 {
1320         int ret;
1321         struct dlm_ctxt *dlm = NULL;
1322         struct dlm_ctxt *new_ctxt = NULL;
1323
1324         if (strlen(domain) > O2NM_MAX_NAME_LEN) {
1325                 ret = -ENAMETOOLONG;
1326                 mlog(ML_ERROR, "domain name length too long\n");
1327                 goto leave;
1328         }
1329
1330         if (!o2hb_check_local_node_heartbeating()) {
1331                 mlog(ML_ERROR, "the local node has not been configured, or is "
1332                      "not heartbeating\n");
1333                 ret = -EPROTO;
1334                 goto leave;
1335         }
1336
1337         mlog(0, "register called for domain \"%s\"\n", domain);
1338
1339 retry:
1340         dlm = NULL;
1341         if (signal_pending(current)) {
1342                 ret = -ERESTARTSYS;
1343                 mlog_errno(ret);
1344                 goto leave;
1345         }
1346
1347         spin_lock(&dlm_domain_lock);
1348
1349         dlm = __dlm_lookup_domain(domain);
1350         if (dlm) {
1351                 if (dlm->dlm_state != DLM_CTXT_JOINED) {
1352                         spin_unlock(&dlm_domain_lock);
1353
1354                         mlog(0, "This ctxt is not joined yet!\n");
1355                         wait_event_interruptible(dlm_domain_events,
1356                                                  dlm_wait_on_domain_helper(
1357                                                          domain));
1358                         goto retry;
1359                 }
1360
1361                 __dlm_get(dlm);
1362                 dlm->num_joins++;
1363
1364                 spin_unlock(&dlm_domain_lock);
1365
1366                 ret = 0;
1367                 goto leave;
1368         }
1369
1370         /* doesn't exist */
1371         if (!new_ctxt) {
1372                 spin_unlock(&dlm_domain_lock);
1373
1374                 new_ctxt = dlm_alloc_ctxt(domain, key);
1375                 if (new_ctxt)
1376                         goto retry;
1377
1378                 ret = -ENOMEM;
1379                 mlog_errno(ret);
1380                 goto leave;
1381         }
1382
1383         /* a little variable switch-a-roo here... */
1384         dlm = new_ctxt;
1385         new_ctxt = NULL;
1386
1387         /* add the new domain */
1388         list_add_tail(&dlm->list, &dlm_domains);
1389         spin_unlock(&dlm_domain_lock);
1390
1391         ret = dlm_join_domain(dlm);
1392         if (ret) {
1393                 mlog_errno(ret);
1394                 dlm_put(dlm);
1395                 goto leave;
1396         }
1397
1398         ret = 0;
1399 leave:
1400         if (new_ctxt)
1401                 dlm_free_ctxt_mem(new_ctxt);
1402
1403         if (ret < 0)
1404                 dlm = ERR_PTR(ret);
1405
1406         return dlm;
1407 }
1408 EXPORT_SYMBOL_GPL(dlm_register_domain);
1409
1410 static LIST_HEAD(dlm_join_handlers);
1411
1412 static void dlm_unregister_net_handlers(void)
1413 {
1414         o2net_unregister_handler_list(&dlm_join_handlers);
1415 }
1416
1417 static int dlm_register_net_handlers(void)
1418 {
1419         int status = 0;
1420
1421         status = o2net_register_handler(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY,
1422                                         sizeof(struct dlm_query_join_request),
1423                                         dlm_query_join_handler,
1424                                         NULL, &dlm_join_handlers);
1425         if (status)
1426                 goto bail;
1427
1428         status = o2net_register_handler(DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
1429                                         sizeof(struct dlm_assert_joined),
1430                                         dlm_assert_joined_handler,
1431                                         NULL, &dlm_join_handlers);
1432         if (status)
1433                 goto bail;
1434
1435         status = o2net_register_handler(DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
1436                                         sizeof(struct dlm_cancel_join),
1437                                         dlm_cancel_join_handler,
1438                                         NULL, &dlm_join_handlers);
1439
1440 bail:
1441         if (status < 0)
1442                 dlm_unregister_net_handlers();
1443
1444         return status;
1445 }
1446
1447 /* Domain eviction callback handling.
1448  *
1449  * The file system requires notification of node death *before* the
1450  * dlm completes it's recovery work, otherwise it may be able to
1451  * acquire locks on resources requiring recovery. Since the dlm can
1452  * evict a node from it's domain *before* heartbeat fires, a similar
1453  * mechanism is required. */
1454
1455 /* Eviction is not expected to happen often, so a per-domain lock is
1456  * not necessary. Eviction callbacks are allowed to sleep for short
1457  * periods of time. */
1458 static DECLARE_RWSEM(dlm_callback_sem);
1459
1460 void dlm_fire_domain_eviction_callbacks(struct dlm_ctxt *dlm,
1461                                         int node_num)
1462 {
1463         struct list_head *iter;
1464         struct dlm_eviction_cb *cb;
1465
1466         down_read(&dlm_callback_sem);
1467         list_for_each(iter, &dlm->dlm_eviction_callbacks) {
1468                 cb = list_entry(iter, struct dlm_eviction_cb, ec_item);
1469
1470                 cb->ec_func(node_num, cb->ec_data);
1471         }
1472         up_read(&dlm_callback_sem);
1473 }
1474
1475 void dlm_setup_eviction_cb(struct dlm_eviction_cb *cb,
1476                            dlm_eviction_func *f,
1477                            void *data)
1478 {
1479         INIT_LIST_HEAD(&cb->ec_item);
1480         cb->ec_func = f;
1481         cb->ec_data = data;
1482 }
1483 EXPORT_SYMBOL_GPL(dlm_setup_eviction_cb);
1484
1485 void dlm_register_eviction_cb(struct dlm_ctxt *dlm,
1486                               struct dlm_eviction_cb *cb)
1487 {
1488         down_write(&dlm_callback_sem);
1489         list_add_tail(&cb->ec_item, &dlm->dlm_eviction_callbacks);
1490         up_write(&dlm_callback_sem);
1491 }
1492 EXPORT_SYMBOL_GPL(dlm_register_eviction_cb);
1493
1494 void dlm_unregister_eviction_cb(struct dlm_eviction_cb *cb)
1495 {
1496         down_write(&dlm_callback_sem);
1497         list_del_init(&cb->ec_item);
1498         up_write(&dlm_callback_sem);
1499 }
1500 EXPORT_SYMBOL_GPL(dlm_unregister_eviction_cb);
1501
1502 static int __init dlm_init(void)
1503 {
1504         int status;
1505
1506         dlm_print_version();
1507
1508         status = dlm_init_mle_cache();
1509         if (status)
1510                 return -1;
1511
1512         status = dlm_register_net_handlers();
1513         if (status) {
1514                 dlm_destroy_mle_cache();
1515                 return -1;
1516         }
1517
1518         return 0;
1519 }
1520
1521 static void __exit dlm_exit (void)
1522 {
1523         dlm_unregister_net_handlers();
1524         dlm_destroy_mle_cache();
1525 }
1526
1527 MODULE_AUTHOR("Oracle");
1528 MODULE_LICENSE("GPL");
1529
1530 module_init(dlm_init);
1531 module_exit(dlm_exit);