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