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/init.h>
  32 #include <linux/spinlock.h>
  33 #include <linux/delay.h>
  34 #include <linux/err.h>
  35 #include <linux/debugfs.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 #include "dlmdomain.h"
  44 #include "dlmdebug.h"
  45
  46 #include "dlmver.h"
  47
  48 #define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_DOMAIN)
  49 #include "cluster/masklog.h"
  50
  51 /*
  52  * ocfs2 node maps are array of long int, which limits to send them freely
  53  * across the wire due to endianness issues. To workaround this, we convert
  54  * long ints to byte arrays. Following 3 routines are helper functions to
  55  * set/test/copy bits within those array of bytes
  56  */
  57 static inline void byte_set_bit(u8 nr, u8 map[])
  58 {
  59         map[nr >> 3] |= (1UL << (nr & 7));
  60 }
  61
  62 static inline int byte_test_bit(u8 nr, u8 map[])
  63 {
  64         return ((1UL << (nr & 7)) & (map[nr >> 3])) != 0;
  65 }
  66
  67 static inline void byte_copymap(u8 dmap[], unsigned long smap[],
  68                         unsigned int sz)
  69 {
  70         unsigned int nn;
  71
  72         if (!sz)
  73                 return;
  74
  75         memset(dmap, 0, ((sz + 7) >> 3));
  76         for (nn = 0 ; nn < sz; nn++)
  77                 if (test_bit(nn, smap))
  78                         byte_set_bit(nn, dmap);
  79 }
  80
  81 static void dlm_free_pagevec(void **vec, int pages)
  82 {
  83         while (pages--)
  84                 free_page((unsigned long)vec[pages]);
  85         kfree(vec);
  86 }
  87
  88 static void **dlm_alloc_pagevec(int pages)
  89 {
  90         void **vec = kmalloc(pages * sizeof(void *), GFP_KERNEL);
  91         int i;
  92
  93         if (!vec)
  94                 return NULL;
  95
  96         for (i = 0; i < pages; i++)
  97                 if (!(vec[i] = (void *)__get_free_page(GFP_KERNEL)))
  98                         goto out_free;
  99
 100         mlog(0, "Allocated DLM hash pagevec; %d pages (%lu expected), %lu buckets per page\n",
 101              pages, (unsigned long)DLM_HASH_PAGES,
 102              (unsigned long)DLM_BUCKETS_PER_PAGE);
 103         return vec;
 104 out_free:
 105         dlm_free_pagevec(vec, i);
 106         return NULL;
 107 }
 108
 109 /*
 110  *
 111  * spinlock lock ordering: if multiple locks are needed, obey this ordering:
 112  *    dlm_domain_lock
 113  *    struct dlm_ctxt->spinlock
 114  *    struct dlm_lock_resource->spinlock
 115  *    struct dlm_ctxt->master_lock
 116  *    struct dlm_ctxt->ast_lock
 117  *    dlm_master_list_entry->spinlock
 118  *    dlm_lock->spinlock
 119  *
 120  */
 121
 122 DEFINE_SPINLOCK(dlm_domain_lock);
 123 LIST_HEAD(dlm_domains);
 124 static DECLARE_WAIT_QUEUE_HEAD(dlm_domain_events);
 125
 126 /*
 127  * The supported protocol version for DLM communication.  Running domains
 128  * will have a negotiated version with the same major number and a minor
 129  * number equal or smaller.  The dlm_ctxt->dlm_locking_proto field should
 130  * be used to determine what a running domain is actually using.
 131  */
 132 static const struct dlm_protocol_version dlm_protocol = {
 133         .pv_major = 1,
 134         .pv_minor = 0,
 135 };
 136
 137 #define DLM_DOMAIN_BACKOFF_MS 200
 138
 139 static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
 140                                   void **ret_data);
 141 static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data,
 142                                      void **ret_data);
 143 static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data,
 144                                    void **ret_data);
 145 static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data,
 146                                    void **ret_data);
 147 static int dlm_protocol_compare(struct dlm_protocol_version *existing,
 148                                 struct dlm_protocol_version *request);
 149
 150 static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm);
 151
 152 void __dlm_unhash_lockres(struct dlm_lock_resource *lockres)
 153 {
 154         if (!hlist_unhashed(&lockres->hash_node)) {
 155                 hlist_del_init(&lockres->hash_node);
 156                 dlm_lockres_put(lockres);
 157         }
 158 }
 159
 160 void __dlm_insert_lockres(struct dlm_ctxt *dlm,
 161                        struct dlm_lock_resource *res)
 162 {
 163         struct hlist_head *bucket;
 164         struct qstr *q;
 165
 166         assert_spin_locked(&dlm->spinlock);
 167
 168         q = &res->lockname;
 169         bucket = dlm_lockres_hash(dlm, q->hash);
 170
 171         /* get a reference for our hashtable */
 172         dlm_lockres_get(res);
 173
 174         hlist_add_head(&res->hash_node, bucket);
 175 }
 176
 177 struct dlm_lock_resource * __dlm_lookup_lockres_full(struct dlm_ctxt *dlm,
 178                                                      const char *name,
 179                                                      unsigned int len,
 180                                                      unsigned int hash)
 181 {
 182         struct hlist_head *bucket;
 183         struct hlist_node *list;
 184
 185         mlog_entry("%.*s\n", len, name);
 186
 187         assert_spin_locked(&dlm->spinlock);
 188
 189         bucket = dlm_lockres_hash(dlm, hash);
 190
 191         hlist_for_each(list, bucket) {
 192                 struct dlm_lock_resource *res = hlist_entry(list,
 193                         struct dlm_lock_resource, hash_node);
 194                 if (res->lockname.name[0] != name[0])
 195                         continue;
 196                 if (unlikely(res->lockname.len != len))
 197                         continue;
 198                 if (memcmp(res->lockname.name + 1, name + 1, len - 1))
 199                         continue;
 200                 dlm_lockres_get(res);
 201                 return res;
 202         }
 203         return NULL;
 204 }
 205
 206 /* intended to be called by functions which do not care about lock
 207  * resources which are being purged (most net _handler functions).
 208  * this will return NULL for any lock resource which is found but
 209  * currently in the process of dropping its mastery reference.
 210  * use __dlm_lookup_lockres_full when you need the lock resource
 211  * regardless (e.g. dlm_get_lock_resource) */
 212 struct dlm_lock_resource * __dlm_lookup_lockres(struct dlm_ctxt *dlm,
 213                                                 const char *name,
 214                                                 unsigned int len,
 215                                                 unsigned int hash)
 216 {
 217         struct dlm_lock_resource *res = NULL;
 218
 219         mlog_entry("%.*s\n", len, name);
 220
 221         assert_spin_locked(&dlm->spinlock);
 222
 223         res = __dlm_lookup_lockres_full(dlm, name, len, hash);
 224         if (res) {
 225                 spin_lock(&res->spinlock);
 226                 if (res->state & DLM_LOCK_RES_DROPPING_REF) {
 227                         spin_unlock(&res->spinlock);
 228                         dlm_lockres_put(res);
 229                         return NULL;
 230                 }
 231                 spin_unlock(&res->spinlock);
 232         }
 233
 234         return res;
 235 }
 236
 237 struct dlm_lock_resource * dlm_lookup_lockres(struct dlm_ctxt *dlm,
 238                                     const char *name,
 239                                     unsigned int len)
 240 {
 241         struct dlm_lock_resource *res;
 242         unsigned int hash = dlm_lockid_hash(name, len);
 243
 244         spin_lock(&dlm->spinlock);
 245         res = __dlm_lookup_lockres(dlm, name, len, hash);
 246         spin_unlock(&dlm->spinlock);
 247         return res;
 248 }
 249
 250 static struct dlm_ctxt * __dlm_lookup_domain_full(const char *domain, int len)
 251 {
 252         struct dlm_ctxt *tmp = NULL;
 253         struct list_head *iter;
 254
 255         assert_spin_locked(&dlm_domain_lock);
 256
 257         /* tmp->name here is always NULL terminated,
 258          * but domain may not be! */
 259         list_for_each(iter, &dlm_domains) {
 260                 tmp = list_entry (iter, struct dlm_ctxt, list);
 261                 if (strlen(tmp->name) == len &&
 262                     memcmp(tmp->name, domain, len)==0)
 263                         break;
 264                 tmp = NULL;
 265         }
 266
 267         return tmp;
 268 }
 269
 270 /* For null terminated domain strings ONLY */
 271 static struct dlm_ctxt * __dlm_lookup_domain(const char *domain)
 272 {
 273         assert_spin_locked(&dlm_domain_lock);
 274
 275         return __dlm_lookup_domain_full(domain, strlen(domain));
 276 }
 277
 278
 279 /* returns true on one of two conditions:
 280  * 1) the domain does not exist
 281  * 2) the domain exists and it's state is "joined" */
 282 static int dlm_wait_on_domain_helper(const char *domain)
 283 {
 284         int ret = 0;
 285         struct dlm_ctxt *tmp = NULL;
 286
 287         spin_lock(&dlm_domain_lock);
 288
 289         tmp = __dlm_lookup_domain(domain);
 290         if (!tmp)
 291                 ret = 1;
 292         else if (tmp->dlm_state == DLM_CTXT_JOINED)
 293                 ret = 1;
 294
 295         spin_unlock(&dlm_domain_lock);
 296         return ret;
 297 }
 298
 299 static void dlm_free_ctxt_mem(struct dlm_ctxt *dlm)
 300 {
 301         dlm_destroy_debugfs_subroot(dlm);
 302
 303         if (dlm->lockres_hash)
 304                 dlm_free_pagevec((void **)dlm->lockres_hash, DLM_HASH_PAGES);
 305
 306         if (dlm->master_hash)
 307                 dlm_free_pagevec((void **)dlm->master_hash, DLM_HASH_PAGES);
 308
 309         if (dlm->name)
 310                 kfree(dlm->name);
 311
 312         kfree(dlm);
 313 }
 314
 315 /* A little strange - this function will be called while holding
 316  * dlm_domain_lock and is expected to be holding it on the way out. We
 317  * will however drop and reacquire it multiple times */
 318 static void dlm_ctxt_release(struct kref *kref)
 319 {
 320         struct dlm_ctxt *dlm;
 321
 322         dlm = container_of(kref, struct dlm_ctxt, dlm_refs);
 323
 324         BUG_ON(dlm->num_joins);
 325         BUG_ON(dlm->dlm_state == DLM_CTXT_JOINED);
 326
 327         /* we may still be in the list if we hit an error during join. */
 328         list_del_init(&dlm->list);
 329
 330         spin_unlock(&dlm_domain_lock);
 331
 332         mlog(0, "freeing memory from domain %s\n", dlm->name);
 333
 334         wake_up(&dlm_domain_events);
 335
 336         dlm_free_ctxt_mem(dlm);
 337
 338         spin_lock(&dlm_domain_lock);
 339 }
 340
 341 void dlm_put(struct dlm_ctxt *dlm)
 342 {
 343         spin_lock(&dlm_domain_lock);
 344         kref_put(&dlm->dlm_refs, dlm_ctxt_release);
 345         spin_unlock(&dlm_domain_lock);
 346 }
 347
 348 static void __dlm_get(struct dlm_ctxt *dlm)
 349 {
 350         kref_get(&dlm->dlm_refs);
 351 }
 352
 353 /* given a questionable reference to a dlm object, gets a reference if
 354  * it can find it in the list, otherwise returns NULL in which case
 355  * you shouldn't trust your pointer. */
 356 struct dlm_ctxt *dlm_grab(struct dlm_ctxt *dlm)
 357 {
 358         struct list_head *iter;
 359         struct dlm_ctxt *target = NULL;
 360
 361         spin_lock(&dlm_domain_lock);
 362
 363         list_for_each(iter, &dlm_domains) {
 364                 target = list_entry (iter, struct dlm_ctxt, list);
 365
 366                 if (target == dlm) {
 367                         __dlm_get(target);
 368                         break;
 369                 }
 370
 371                 target = NULL;
 372         }
 373
 374         spin_unlock(&dlm_domain_lock);
 375
 376         return target;
 377 }
 378
 379 int dlm_domain_fully_joined(struct dlm_ctxt *dlm)
 380 {
 381         int ret;
 382
 383         spin_lock(&dlm_domain_lock);
 384         ret = (dlm->dlm_state == DLM_CTXT_JOINED) ||
 385                 (dlm->dlm_state == DLM_CTXT_IN_SHUTDOWN);
 386         spin_unlock(&dlm_domain_lock);
 387
 388         return ret;
 389 }
 390
 391 static void dlm_destroy_dlm_worker(struct dlm_ctxt *dlm)
 392 {
 393         if (dlm->dlm_worker) {
 394                 flush_workqueue(dlm->dlm_worker);
 395                 destroy_workqueue(dlm->dlm_worker);
 396                 dlm->dlm_worker = NULL;
 397         }
 398 }
 399
 400 static void dlm_complete_dlm_shutdown(struct dlm_ctxt *dlm)
 401 {
 402         dlm_unregister_domain_handlers(dlm);
 403         dlm_debug_shutdown(dlm);
 404         dlm_complete_thread(dlm);
 405         dlm_complete_recovery_thread(dlm);
 406         dlm_destroy_dlm_worker(dlm);
 407
 408         /* We've left the domain. Now we can take ourselves out of the
 409          * list and allow the kref stuff to help us free the
 410          * memory. */
 411         spin_lock(&dlm_domain_lock);
 412         list_del_init(&dlm->list);
 413         spin_unlock(&dlm_domain_lock);
 414
 415         /* Wake up anyone waiting for us to remove this domain */
 416         wake_up(&dlm_domain_events);
 417 }
 418
 419 static int dlm_migrate_all_locks(struct dlm_ctxt *dlm)
 420 {
 421         int i, num, n, ret = 0;
 422         struct dlm_lock_resource *res;
 423         struct hlist_node *iter;
 424         struct hlist_head *bucket;
 425         int dropped;
 426
 427         mlog(0, "Migrating locks from domain %s\n", dlm->name);
 428
 429         num = 0;
 430         spin_lock(&dlm->spinlock);
 431         for (i = 0; i < DLM_HASH_BUCKETS; i++) {
 432 redo_bucket:
 433                 n = 0;
 434                 bucket = dlm_lockres_hash(dlm, i);
 435                 iter = bucket->first;
 436                 while (iter) {
 437                         n++;
 438                         res = hlist_entry(iter, struct dlm_lock_resource,
 439                                           hash_node);
 440                         dlm_lockres_get(res);
 441                         /* migrate, if necessary.  this will drop the dlm
 442                          * spinlock and retake it if it does migration. */
 443                         dropped = dlm_empty_lockres(dlm, res);
 444
 445                         spin_lock(&res->spinlock);
 446                         __dlm_lockres_calc_usage(dlm, res);
 447                         iter = res->hash_node.next;
 448                         spin_unlock(&res->spinlock);
 449
 450                         dlm_lockres_put(res);
 451
 452                         if (dropped)
 453                                 goto redo_bucket;
 454                 }
 455                 cond_resched_lock(&dlm->spinlock);
 456                 num += n;
 457                 mlog(0, "%s: touched %d lockreses in bucket %d "
 458                      "(tot=%d)\n", dlm->name, n, i, num);
 459         }
 460         spin_unlock(&dlm->spinlock);
 461         wake_up(&dlm->dlm_thread_wq);
 462
 463         /* let the dlm thread take care of purging, keep scanning until
 464          * nothing remains in the hash */
 465         if (num) {
 466                 mlog(0, "%s: %d lock resources in hash last pass\n",
 467                      dlm->name, num);
 468                 ret = -EAGAIN;
 469         }
 470         mlog(0, "DONE Migrating locks from domain %s\n", dlm->name);
 471         return ret;
 472 }
 473
 474 static int dlm_no_joining_node(struct dlm_ctxt *dlm)
 475 {
 476         int ret;
 477
 478         spin_lock(&dlm->spinlock);
 479         ret = dlm->joining_node == DLM_LOCK_RES_OWNER_UNKNOWN;
 480         spin_unlock(&dlm->spinlock);
 481
 482         return ret;
 483 }
 484
 485 static void dlm_mark_domain_leaving(struct dlm_ctxt *dlm)
 486 {
 487         /* Yikes, a double spinlock! I need domain_lock for the dlm
 488          * state and the dlm spinlock for join state... Sorry! */
 489 again:
 490         spin_lock(&dlm_domain_lock);
 491         spin_lock(&dlm->spinlock);
 492
 493         if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
 494                 mlog(0, "Node %d is joining, we wait on it.\n",
 495                           dlm->joining_node);
 496                 spin_unlock(&dlm->spinlock);
 497                 spin_unlock(&dlm_domain_lock);
 498
 499                 wait_event(dlm->dlm_join_events, dlm_no_joining_node(dlm));
 500                 goto again;
 501         }
 502
 503         dlm->dlm_state = DLM_CTXT_LEAVING;
 504         spin_unlock(&dlm->spinlock);
 505         spin_unlock(&dlm_domain_lock);
 506 }
 507
 508 static void __dlm_print_nodes(struct dlm_ctxt *dlm)
 509 {
 510         int node = -1;
 511
 512         assert_spin_locked(&dlm->spinlock);
 513
 514         printk(KERN_NOTICE "o2dlm: Nodes in domain %s: ", dlm->name);
 515
 516         while ((node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES,
 517                                      node + 1)) < O2NM_MAX_NODES) {
 518                 printk("%d ", node);
 519         }
 520         printk("\n");
 521 }
 522
 523 static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data,
 524                                    void **ret_data)
 525 {
 526         struct dlm_ctxt *dlm = data;
 527         unsigned int node;
 528         struct dlm_exit_domain *exit_msg = (struct dlm_exit_domain *) msg->buf;
 529
 530         mlog_entry("%p %u %p", msg, len, data);
 531
 532         if (!dlm_grab(dlm))
 533                 return 0;
 534
 535         node = exit_msg->node_idx;
 536
 537         printk(KERN_NOTICE "o2dlm: Node %u leaves domain %s\n", node, dlm->name);
 538
 539         spin_lock(&dlm->spinlock);
 540         clear_bit(node, dlm->domain_map);
 541         __dlm_print_nodes(dlm);
 542
 543         /* notify anything attached to the heartbeat events */
 544         dlm_hb_event_notify_attached(dlm, node, 0);
 545
 546         spin_unlock(&dlm->spinlock);
 547
 548         dlm_put(dlm);
 549
 550         return 0;
 551 }
 552
 553 static int dlm_send_one_domain_exit(struct dlm_ctxt *dlm,
 554                                     unsigned int node)
 555 {
 556         int status;
 557         struct dlm_exit_domain leave_msg;
 558
 559         mlog(0, "Asking node %u if we can leave the domain %s me = %u\n",
 560                   node, dlm->name, dlm->node_num);
 561
 562         memset(&leave_msg, 0, sizeof(leave_msg));
 563         leave_msg.node_idx = dlm->node_num;
 564
 565         status = o2net_send_message(DLM_EXIT_DOMAIN_MSG, dlm->key,
 566                                     &leave_msg, sizeof(leave_msg), node,
 567                                     NULL);
 568         if (status < 0)
 569                 mlog(ML_ERROR, "Error %d when sending message %u (key 0x%x) to "
 570                      "node %u\n", status, DLM_EXIT_DOMAIN_MSG, dlm->key, node);
 571         mlog(0, "status return %d from o2net_send_message\n", status);
 572
 573         return status;
 574 }
 575
 576
 577 static void dlm_leave_domain(struct dlm_ctxt *dlm)
 578 {
 579         int node, clear_node, status;
 580
 581         /* At this point we've migrated away all our locks and won't
 582          * accept mastership of new ones. The dlm is responsible for
 583          * almost nothing now. We make sure not to confuse any joining
 584          * nodes and then commence shutdown procedure. */
 585
 586         spin_lock(&dlm->spinlock);
 587         /* Clear ourselves from the domain map */
 588         clear_bit(dlm->node_num, dlm->domain_map);
 589         while ((node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES,
 590                                      0)) < O2NM_MAX_NODES) {
 591                 /* Drop the dlm spinlock. This is safe wrt the domain_map.
 592                  * -nodes cannot be added now as the
 593                  *   query_join_handlers knows to respond with OK_NO_MAP
 594                  * -we catch the right network errors if a node is
 595                  *   removed from the map while we're sending him the
 596                  *   exit message. */
 597                 spin_unlock(&dlm->spinlock);
 598
 599                 clear_node = 1;
 600
 601                 status = dlm_send_one_domain_exit(dlm, node);
 602                 if (status < 0 &&
 603                     status != -ENOPROTOOPT &&
 604                     status != -ENOTCONN) {
 605                         mlog(ML_NOTICE, "Error %d sending domain exit message "
 606                              "to node %d\n", status, node);
 607
 608                         /* Not sure what to do here but lets sleep for
 609                          * a bit in case this was a transient
 610                          * error... */
 611                         msleep(DLM_DOMAIN_BACKOFF_MS);
 612                         clear_node = 0;
 613                 }
 614
 615                 spin_lock(&dlm->spinlock);
 616                 /* If we're not clearing the node bit then we intend
 617                  * to loop back around to try again. */
 618                 if (clear_node)
 619                         clear_bit(node, dlm->domain_map);
 620         }
 621         spin_unlock(&dlm->spinlock);
 622 }
 623
 624 int dlm_joined(struct dlm_ctxt *dlm)
 625 {
 626         int ret = 0;
 627
 628         spin_lock(&dlm_domain_lock);
 629
 630         if (dlm->dlm_state == DLM_CTXT_JOINED)
 631                 ret = 1;
 632
 633         spin_unlock(&dlm_domain_lock);
 634
 635         return ret;
 636 }
 637
 638 int dlm_shutting_down(struct dlm_ctxt *dlm)
 639 {
 640         int ret = 0;
 641
 642         spin_lock(&dlm_domain_lock);
 643
 644         if (dlm->dlm_state == DLM_CTXT_IN_SHUTDOWN)
 645                 ret = 1;
 646
 647         spin_unlock(&dlm_domain_lock);
 648
 649         return ret;
 650 }
 651
 652 void dlm_unregister_domain(struct dlm_ctxt *dlm)
 653 {
 654         int leave = 0;
 655         struct dlm_lock_resource *res;
 656
 657         spin_lock(&dlm_domain_lock);
 658         BUG_ON(dlm->dlm_state != DLM_CTXT_JOINED);
 659         BUG_ON(!dlm->num_joins);
 660
 661         dlm->num_joins--;
 662         if (!dlm->num_joins) {
 663                 /* We mark it "in shutdown" now so new register
 664                  * requests wait until we've completely left the
 665                  * domain. Don't use DLM_CTXT_LEAVING yet as we still
 666                  * want new domain joins to communicate with us at
 667                  * least until we've completed migration of our
 668                  * resources. */
 669                 dlm->dlm_state = DLM_CTXT_IN_SHUTDOWN;
 670                 leave = 1;
 671         }
 672         spin_unlock(&dlm_domain_lock);
 673
 674         if (leave) {
 675                 mlog(0, "shutting down domain %s\n", dlm->name);
 676
 677                 /* We changed dlm state, notify the thread */
 678                 dlm_kick_thread(dlm, NULL);
 679
 680                 while (dlm_migrate_all_locks(dlm)) {
 681                         /* Give dlm_thread time to purge the lockres' */
 682                         msleep(500);
 683                         mlog(0, "%s: more migration to do\n", dlm->name);
 684                 }
 685
 686                 /* This list should be empty. If not, print remaining lockres */
 687                 if (!list_empty(&dlm->tracking_list)) {
 688                         mlog(ML_ERROR, "Following lockres' are still on the "
 689                              "tracking list:\n");
 690                         list_for_each_entry(res, &dlm->tracking_list, tracking)
 691                                 dlm_print_one_lock_resource(res);
 692                 }
 693
 694                 dlm_mark_domain_leaving(dlm);
 695                 dlm_leave_domain(dlm);
 696                 dlm_complete_dlm_shutdown(dlm);
 697         }
 698         dlm_put(dlm);
 699 }
 700 EXPORT_SYMBOL_GPL(dlm_unregister_domain);
 701
 702 static int dlm_query_join_proto_check(char *proto_type, int node,
 703                                       struct dlm_protocol_version *ours,
 704                                       struct dlm_protocol_version *request)
 705 {
 706         int rc;
 707         struct dlm_protocol_version proto = *request;
 708
 709         if (!dlm_protocol_compare(ours, &proto)) {
 710                 mlog(0,
 711                      "node %u wanted to join with %s locking protocol "
 712                      "%u.%u, we respond with %u.%u\n",
 713                      node, proto_type,
 714                      request->pv_major,
 715                      request->pv_minor,
 716                      proto.pv_major, proto.pv_minor);
 717                 request->pv_minor = proto.pv_minor;
 718                 rc = 0;
 719         } else {
 720                 mlog(ML_NOTICE,
 721                      "Node %u wanted to join with %s locking "
 722                      "protocol %u.%u, but we have %u.%u, disallowing\n",
 723                      node, proto_type,
 724                      request->pv_major,
 725                      request->pv_minor,
 726                      ours->pv_major,
 727                      ours->pv_minor);
 728                 rc = 1;
 729         }
 730
 731         return rc;
 732 }
 733
 734 /*
 735  * struct dlm_query_join_packet is made up of four one-byte fields.  They
 736  * are effectively in big-endian order already.  However, little-endian
 737  * machines swap them before putting the packet on the wire (because
 738  * query_join's response is a status, and that status is treated as a u32
 739  * on the wire).  Thus, a big-endian and little-endian machines will treat
 740  * this structure differently.
 741  *
 742  * The solution is to have little-endian machines swap the structure when
 743  * converting from the structure to the u32 representation.  This will
 744  * result in the structure having the correct format on the wire no matter
 745  * the host endian format.
 746  */
 747 static void dlm_query_join_packet_to_wire(struct dlm_query_join_packet *packet,
 748                                           u32 *wire)
 749 {
 750         union dlm_query_join_response response;
 751
 752         response.packet = *packet;
 753         *wire = cpu_to_be32(response.intval);
 754 }
 755
 756 static void dlm_query_join_wire_to_packet(u32 wire,
 757                                           struct dlm_query_join_packet *packet)
 758 {
 759         union dlm_query_join_response response;
 760
 761         response.intval = cpu_to_be32(wire);
 762         *packet = response.packet;
 763 }
 764
 765 static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
 766                                   void **ret_data)
 767 {
 768         struct dlm_query_join_request *query;
 769         struct dlm_query_join_packet packet = {
 770                 .code = JOIN_DISALLOW,
 771         };
 772         struct dlm_ctxt *dlm = NULL;
 773         u32 response;
 774         u8 nodenum;
 775
 776         query = (struct dlm_query_join_request *) msg->buf;
 777
 778         mlog(0, "node %u wants to join domain %s\n", query->node_idx,
 779                   query->domain);
 780
 781         /*
 782          * If heartbeat doesn't consider the node live, tell it
 783          * to back off and try again.  This gives heartbeat a chance
 784          * to catch up.
 785          */
 786         if (!o2hb_check_node_heartbeating(query->node_idx)) {
 787                 mlog(0, "node %u is not in our live map yet\n",
 788                      query->node_idx);
 789
 790                 packet.code = JOIN_DISALLOW;
 791                 goto respond;
 792         }
 793
 794         packet.code = JOIN_OK_NO_MAP;
 795
 796         spin_lock(&dlm_domain_lock);
 797         dlm = __dlm_lookup_domain_full(query->domain, query->name_len);
 798         if (!dlm)
 799                 goto unlock_respond;
 800
 801         /*
 802          * There is a small window where the joining node may not see the
 803          * node(s) that just left but still part of the cluster. DISALLOW
 804          * join request if joining node has different node map.
 805          */
 806         nodenum=0;
 807         while (nodenum < O2NM_MAX_NODES) {
 808                 if (test_bit(nodenum, dlm->domain_map)) {
 809                         if (!byte_test_bit(nodenum, query->node_map)) {
 810                                 mlog(0, "disallow join as node %u does not "
 811                                      "have node %u in its nodemap\n",
 812                                      query->node_idx, nodenum);
 813                                 packet.code = JOIN_DISALLOW;
 814                                 goto unlock_respond;
 815                         }
 816                 }
 817                 nodenum++;
 818         }
 819
 820         /* Once the dlm ctxt is marked as leaving then we don't want
 821          * to be put in someone's domain map.
 822          * Also, explicitly disallow joining at certain troublesome
 823          * times (ie. during recovery). */
 824         if (dlm && dlm->dlm_state != DLM_CTXT_LEAVING) {
 825                 int bit = query->node_idx;
 826                 spin_lock(&dlm->spinlock);
 827
 828                 if (dlm->dlm_state == DLM_CTXT_NEW &&
 829                     dlm->joining_node == DLM_LOCK_RES_OWNER_UNKNOWN) {
 830                         /*If this is a brand new context and we
 831                          * haven't started our join process yet, then
 832                          * the other node won the race. */
 833                         packet.code = JOIN_OK_NO_MAP;
 834                 } else if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
 835                         /* Disallow parallel joins. */
 836                         packet.code = JOIN_DISALLOW;
 837                 } else if (dlm->reco.state & DLM_RECO_STATE_ACTIVE) {
 838                         mlog(0, "node %u trying to join, but recovery "
 839                              "is ongoing.\n", bit);
 840                         packet.code = JOIN_DISALLOW;
 841                 } else if (test_bit(bit, dlm->recovery_map)) {
 842                         mlog(0, "node %u trying to join, but it "
 843                              "still needs recovery.\n", bit);
 844                         packet.code = JOIN_DISALLOW;
 845                 } else if (test_bit(bit, dlm->domain_map)) {
 846                         mlog(0, "node %u trying to join, but it "
 847                              "is still in the domain! needs recovery?\n",
 848                              bit);
 849                         packet.code = JOIN_DISALLOW;
 850                 } else {
 851                         /* Alright we're fully a part of this domain
 852                          * so we keep some state as to who's joining
 853                          * and indicate to him that needs to be fixed
 854                          * up. */
 855
 856                         /* Make sure we speak compatible locking protocols.  */
 857                         if (dlm_query_join_proto_check("DLM", bit,
 858                                                        &dlm->dlm_locking_proto,
 859                                                        &query->dlm_proto)) {
 860                                 packet.code = JOIN_PROTOCOL_MISMATCH;
 861                         } else if (dlm_query_join_proto_check("fs", bit,
 862                                                               &dlm->fs_locking_proto,
 863                                                               &query->fs_proto)) {
 864                                 packet.code = JOIN_PROTOCOL_MISMATCH;
 865                         } else {
 866                                 packet.dlm_minor = query->dlm_proto.pv_minor;
 867                                 packet.fs_minor = query->fs_proto.pv_minor;
 868                                 packet.code = JOIN_OK;
 869                                 __dlm_set_joining_node(dlm, query->node_idx);
 870                         }
 871                 }
 872
 873                 spin_unlock(&dlm->spinlock);
 874         }
 875 unlock_respond:
 876         spin_unlock(&dlm_domain_lock);
 877
 878 respond:
 879         mlog(0, "We respond with %u\n", packet.code);
 880
 881         dlm_query_join_packet_to_wire(&packet, &response);
 882         return response;
 883 }
 884
 885 static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data,
 886                                      void **ret_data)
 887 {
 888         struct dlm_assert_joined *assert;
 889         struct dlm_ctxt *dlm = NULL;
 890
 891         assert = (struct dlm_assert_joined *) msg->buf;
 892
 893         mlog(0, "node %u asserts join on domain %s\n", assert->node_idx,
 894                   assert->domain);
 895
 896         spin_lock(&dlm_domain_lock);
 897         dlm = __dlm_lookup_domain_full(assert->domain, assert->name_len);
 898         /* XXX should we consider no dlm ctxt an error? */
 899         if (dlm) {
 900                 spin_lock(&dlm->spinlock);
 901
 902                 /* Alright, this node has officially joined our
 903                  * domain. Set him in the map and clean up our
 904                  * leftover join state. */
 905                 BUG_ON(dlm->joining_node != assert->node_idx);
 906                 set_bit(assert->node_idx, dlm->domain_map);
 907                 __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
 908
 909                 printk(KERN_NOTICE "o2dlm: Node %u joins domain %s\n",
 910                        assert->node_idx, dlm->name);
 911                 __dlm_print_nodes(dlm);
 912
 913                 /* notify anything attached to the heartbeat events */
 914                 dlm_hb_event_notify_attached(dlm, assert->node_idx, 1);
 915
 916                 spin_unlock(&dlm->spinlock);
 917         }
 918         spin_unlock(&dlm_domain_lock);
 919
 920         return 0;
 921 }
 922
 923 static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data,
 924                                    void **ret_data)
 925 {
 926         struct dlm_cancel_join *cancel;
 927         struct dlm_ctxt *dlm = NULL;
 928
 929         cancel = (struct dlm_cancel_join *) msg->buf;
 930
 931         mlog(0, "node %u cancels join on domain %s\n", cancel->node_idx,
 932                   cancel->domain);
 933
 934         spin_lock(&dlm_domain_lock);
 935         dlm = __dlm_lookup_domain_full(cancel->domain, cancel->name_len);
 936
 937         if (dlm) {
 938                 spin_lock(&dlm->spinlock);
 939
 940                 /* Yikes, this guy wants to cancel his join. No
 941                  * problem, we simply cleanup our join state. */
 942                 BUG_ON(dlm->joining_node != cancel->node_idx);
 943                 __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
 944
 945                 spin_unlock(&dlm->spinlock);
 946         }
 947         spin_unlock(&dlm_domain_lock);
 948
 949         return 0;
 950 }
 951
 952 static int dlm_send_one_join_cancel(struct dlm_ctxt *dlm,
 953                                     unsigned int node)
 954 {
 955         int status;
 956         struct dlm_cancel_join cancel_msg;
 957
 958         memset(&cancel_msg, 0, sizeof(cancel_msg));
 959         cancel_msg.node_idx = dlm->node_num;
 960         cancel_msg.name_len = strlen(dlm->name);
 961         memcpy(cancel_msg.domain, dlm->name, cancel_msg.name_len);
 962
 963         status = o2net_send_message(DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
 964                                     &cancel_msg, sizeof(cancel_msg), node,
 965                                     NULL);
 966         if (status < 0) {
 967                 mlog(ML_ERROR, "Error %d when sending message %u (key 0x%x) to "
 968                      "node %u\n", status, DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
 969                      node);
 970                 goto bail;
 971         }
 972
 973 bail:
 974         return status;
 975 }
 976
 977 /* map_size should be in bytes. */
 978 static int dlm_send_join_cancels(struct dlm_ctxt *dlm,
 979                                  unsigned long *node_map,
 980                                  unsigned int map_size)
 981 {
 982         int status, tmpstat;
 983         unsigned int node;
 984
 985         if (map_size != (BITS_TO_LONGS(O2NM_MAX_NODES) *
 986                          sizeof(unsigned long))) {
 987                 mlog(ML_ERROR,
 988                      "map_size %u != BITS_TO_LONGS(O2NM_MAX_NODES) %u\n",
 989                      map_size, (unsigned)BITS_TO_LONGS(O2NM_MAX_NODES));
 990                 return -EINVAL;
 991         }
 992
 993         status = 0;
 994         node = -1;
 995         while ((node = find_next_bit(node_map, O2NM_MAX_NODES,
 996                                      node + 1)) < O2NM_MAX_NODES) {
 997                 if (node == dlm->node_num)
 998                         continue;
 999
1000                 tmpstat = dlm_send_one_join_cancel(dlm, node);
1001                 if (tmpstat) {
1002                         mlog(ML_ERROR, "Error return %d cancelling join on "
1003                              "node %d\n", tmpstat, node);
1004                         if (!status)
1005                                 status = tmpstat;
1006                 }
1007         }
1008
1009         if (status)
1010                 mlog_errno(status);
1011         return status;
1012 }
1013
1014 static int dlm_request_join(struct dlm_ctxt *dlm,
1015                             int node,
1016                             enum dlm_query_join_response_code *response)
1017 {
1018         int status;
1019         struct dlm_query_join_request join_msg;
1020         struct dlm_query_join_packet packet;
1021         u32 join_resp;
1022
1023         mlog(0, "querying node %d\n", node);
1024
1025         memset(&join_msg, 0, sizeof(join_msg));
1026         join_msg.node_idx = dlm->node_num;
1027         join_msg.name_len = strlen(dlm->name);
1028         memcpy(join_msg.domain, dlm->name, join_msg.name_len);
1029         join_msg.dlm_proto = dlm->dlm_locking_proto;
1030         join_msg.fs_proto = dlm->fs_locking_proto;
1031
1032         /* copy live node map to join message */
1033         byte_copymap(join_msg.node_map, dlm->live_nodes_map, O2NM_MAX_NODES);
1034
1035         status = o2net_send_message(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY, &join_msg,
1036                                     sizeof(join_msg), node, &join_resp);
1037         if (status < 0 && status != -ENOPROTOOPT) {
1038                 mlog(ML_ERROR, "Error %d when sending message %u (key 0x%x) to "
1039                      "node %u\n", status, DLM_QUERY_JOIN_MSG, DLM_MOD_KEY,
1040                      node);
1041                 goto bail;
1042         }
1043         dlm_query_join_wire_to_packet(join_resp, &packet);
1044
1045         /* -ENOPROTOOPT from the net code means the other side isn't
1046             listening for our message type -- that's fine, it means
1047             his dlm isn't up, so we can consider him a 'yes' but not
1048             joined into the domain.  */
1049         if (status == -ENOPROTOOPT) {
1050                 status = 0;
1051                 *response = JOIN_OK_NO_MAP;
1052         } else if (packet.code == JOIN_DISALLOW ||
1053                    packet.code == JOIN_OK_NO_MAP) {
1054                 *response = packet.code;
1055         } else if (packet.code == JOIN_PROTOCOL_MISMATCH) {
1056                 mlog(ML_NOTICE,
1057                      "This node requested DLM locking protocol %u.%u and "
1058                      "filesystem locking protocol %u.%u.  At least one of "
1059                      "the protocol versions on node %d is not compatible, "
1060                      "disconnecting\n",
1061                      dlm->dlm_locking_proto.pv_major,
1062                      dlm->dlm_locking_proto.pv_minor,
1063                      dlm->fs_locking_proto.pv_major,
1064                      dlm->fs_locking_proto.pv_minor,
1065                      node);
1066                 status = -EPROTO;
1067                 *response = packet.code;
1068         } else if (packet.code == JOIN_OK) {
1069                 *response = packet.code;
1070                 /* Use the same locking protocol as the remote node */
1071                 dlm->dlm_locking_proto.pv_minor = packet.dlm_minor;
1072                 dlm->fs_locking_proto.pv_minor = packet.fs_minor;
1073                 mlog(0,
1074                      "Node %d responds JOIN_OK with DLM locking protocol "
1075                      "%u.%u and fs locking protocol %u.%u\n",
1076                      node,
1077                      dlm->dlm_locking_proto.pv_major,
1078                      dlm->dlm_locking_proto.pv_minor,
1079                      dlm->fs_locking_proto.pv_major,
1080                      dlm->fs_locking_proto.pv_minor);
1081         } else {
1082                 status = -EINVAL;
1083                 mlog(ML_ERROR, "invalid response %d from node %u\n",
1084                      packet.code, node);
1085         }
1086
1087         mlog(0, "status %d, node %d response is %d\n", status, node,
1088              *response);
1089
1090 bail:
1091         return status;
1092 }
1093
1094 static int dlm_send_one_join_assert(struct dlm_ctxt *dlm,
1095                                     unsigned int node)
1096 {
1097         int status;
1098         struct dlm_assert_joined assert_msg;
1099
1100         mlog(0, "Sending join assert to node %u\n", node);
1101
1102         memset(&assert_msg, 0, sizeof(assert_msg));
1103         assert_msg.node_idx = dlm->node_num;
1104         assert_msg.name_len = strlen(dlm->name);
1105         memcpy(assert_msg.domain, dlm->name, assert_msg.name_len);
1106
1107         status = o2net_send_message(DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
1108                                     &assert_msg, sizeof(assert_msg), node,
1109                                     NULL);
1110         if (status < 0)
1111                 mlog(ML_ERROR, "Error %d when sending message %u (key 0x%x) to "
1112                      "node %u\n", status, DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
1113                      node);
1114
1115         return status;
1116 }
1117
1118 static void dlm_send_join_asserts(struct dlm_ctxt *dlm,
1119                                   unsigned long *node_map)
1120 {
1121         int status, node, live;
1122
1123         status = 0;
1124         node = -1;
1125         while ((node = find_next_bit(node_map, O2NM_MAX_NODES,
1126                                      node + 1)) < O2NM_MAX_NODES) {
1127                 if (node == dlm->node_num)
1128                         continue;
1129
1130                 do {
1131                         /* It is very important that this message be
1132                          * received so we spin until either the node
1133                          * has died or it gets the message. */
1134                         status = dlm_send_one_join_assert(dlm, node);
1135
1136                         spin_lock(&dlm->spinlock);
1137                         live = test_bit(node, dlm->live_nodes_map);
1138                         spin_unlock(&dlm->spinlock);
1139
1140                         if (status) {
1141                                 mlog(ML_ERROR, "Error return %d asserting "
1142                                      "join on node %d\n", status, node);
1143
1144                                 /* give us some time between errors... */
1145                                 if (live)
1146                                         msleep(DLM_DOMAIN_BACKOFF_MS);
1147                         }
1148                 } while (status && live);
1149         }
1150 }
1151
1152 struct domain_join_ctxt {
1153         unsigned long live_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1154         unsigned long yes_resp_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1155 };
1156
1157 static int dlm_should_restart_join(struct dlm_ctxt *dlm,
1158                                    struct domain_join_ctxt *ctxt,
1159                                    enum dlm_query_join_response_code response)
1160 {
1161         int ret;
1162
1163         if (response == JOIN_DISALLOW) {
1164                 mlog(0, "Latest response of disallow -- should restart\n");
1165                 return 1;
1166         }
1167
1168         spin_lock(&dlm->spinlock);
1169         /* For now, we restart the process if the node maps have
1170          * changed at all */
1171         ret = memcmp(ctxt->live_map, dlm->live_nodes_map,
1172                      sizeof(dlm->live_nodes_map));
1173         spin_unlock(&dlm->spinlock);
1174
1175         if (ret)
1176                 mlog(0, "Node maps changed -- should restart\n");
1177
1178         return ret;
1179 }
1180
1181 static int dlm_try_to_join_domain(struct dlm_ctxt *dlm)
1182 {
1183         int status = 0, tmpstat, node;
1184         struct domain_join_ctxt *ctxt;
1185         enum dlm_query_join_response_code response = JOIN_DISALLOW;
1186
1187         mlog_entry("%p", dlm);
1188
1189         ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL);
1190         if (!ctxt) {
1191                 status = -ENOMEM;
1192                 mlog_errno(status);
1193                 goto bail;
1194         }
1195
1196         /* group sem locking should work for us here -- we're already
1197          * registered for heartbeat events so filling this should be
1198          * atomic wrt getting those handlers called. */
1199         o2hb_fill_node_map(dlm->live_nodes_map, sizeof(dlm->live_nodes_map));
1200
1201         spin_lock(&dlm->spinlock);
1202         memcpy(ctxt->live_map, dlm->live_nodes_map, sizeof(ctxt->live_map));
1203
1204         __dlm_set_joining_node(dlm, dlm->node_num);
1205
1206         spin_unlock(&dlm->spinlock);
1207
1208         node = -1;
1209         while ((node = find_next_bit(ctxt->live_map, O2NM_MAX_NODES,
1210                                      node + 1)) < O2NM_MAX_NODES) {
1211                 if (node == dlm->node_num)
1212                         continue;
1213
1214                 status = dlm_request_join(dlm, node, &response);
1215                 if (status < 0) {
1216                         mlog_errno(status);
1217                         goto bail;
1218                 }
1219
1220                 /* Ok, either we got a response or the node doesn't have a
1221                  * dlm up. */
1222                 if (response == JOIN_OK)
1223                         set_bit(node, ctxt->yes_resp_map);
1224
1225                 if (dlm_should_restart_join(dlm, ctxt, response)) {
1226                         status = -EAGAIN;
1227                         goto bail;
1228                 }
1229         }
1230
1231         mlog(0, "Yay, done querying nodes!\n");
1232
1233         /* Yay, everyone agree's we can join the domain. My domain is
1234          * comprised of all nodes who were put in the
1235          * yes_resp_map. Copy that into our domain map and send a join
1236          * assert message to clean up everyone elses state. */
1237         spin_lock(&dlm->spinlock);
1238         memcpy(dlm->domain_map, ctxt->yes_resp_map,
1239                sizeof(ctxt->yes_resp_map));
1240         set_bit(dlm->node_num, dlm->domain_map);
1241         spin_unlock(&dlm->spinlock);
1242
1243         dlm_send_join_asserts(dlm, ctxt->yes_resp_map);
1244
1245         /* Joined state *must* be set before the joining node
1246          * information, otherwise the query_join handler may read no
1247          * current joiner but a state of NEW and tell joining nodes
1248          * we're not in the domain. */
1249         spin_lock(&dlm_domain_lock);
1250         dlm->dlm_state = DLM_CTXT_JOINED;
1251         dlm->num_joins++;
1252         spin_unlock(&dlm_domain_lock);
1253
1254 bail:
1255         spin_lock(&dlm->spinlock);
1256         __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
1257         if (!status)
1258                 __dlm_print_nodes(dlm);
1259         spin_unlock(&dlm->spinlock);
1260
1261         if (ctxt) {
1262                 /* Do we need to send a cancel message to any nodes? */
1263                 if (status < 0) {
1264                         tmpstat = dlm_send_join_cancels(dlm,
1265                                                         ctxt->yes_resp_map,
1266                                                         sizeof(ctxt->yes_resp_map));
1267                         if (tmpstat < 0)
1268                                 mlog_errno(tmpstat);
1269                 }
1270                 kfree(ctxt);
1271         }
1272
1273         mlog(0, "returning %d\n", status);
1274         return status;
1275 }
1276
1277 static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm)
1278 {
1279         o2hb_unregister_callback(NULL, &dlm->dlm_hb_up);
1280         o2hb_unregister_callback(NULL, &dlm->dlm_hb_down);
1281         o2net_unregister_handler_list(&dlm->dlm_domain_handlers);
1282 }
1283
1284 static int dlm_register_domain_handlers(struct dlm_ctxt *dlm)
1285 {
1286         int status;
1287
1288         mlog(0, "registering handlers.\n");
1289
1290         o2hb_setup_callback(&dlm->dlm_hb_down, O2HB_NODE_DOWN_CB,
1291                             dlm_hb_node_down_cb, dlm, DLM_HB_NODE_DOWN_PRI);
1292         status = o2hb_register_callback(NULL, &dlm->dlm_hb_down);
1293         if (status)
1294                 goto bail;
1295
1296         o2hb_setup_callback(&dlm->dlm_hb_up, O2HB_NODE_UP_CB,
1297                             dlm_hb_node_up_cb, dlm, DLM_HB_NODE_UP_PRI);
1298         status = o2hb_register_callback(NULL, &dlm->dlm_hb_up);
1299         if (status)
1300                 goto bail;
1301
1302         status = o2net_register_handler(DLM_MASTER_REQUEST_MSG, dlm->key,
1303                                         sizeof(struct dlm_master_request),
1304                                         dlm_master_request_handler,
1305                                         dlm, NULL, &dlm->dlm_domain_handlers);
1306         if (status)
1307                 goto bail;
1308
1309         status = o2net_register_handler(DLM_ASSERT_MASTER_MSG, dlm->key,
1310                                         sizeof(struct dlm_assert_master),
1311                                         dlm_assert_master_handler,
1312                                         dlm, dlm_assert_master_post_handler,
1313                                         &dlm->dlm_domain_handlers);
1314         if (status)
1315                 goto bail;
1316
1317         status = o2net_register_handler(DLM_CREATE_LOCK_MSG, dlm->key,
1318                                         sizeof(struct dlm_create_lock),
1319                                         dlm_create_lock_handler,
1320                                         dlm, NULL, &dlm->dlm_domain_handlers);
1321         if (status)
1322                 goto bail;
1323
1324         status = o2net_register_handler(DLM_CONVERT_LOCK_MSG, dlm->key,
1325                                         DLM_CONVERT_LOCK_MAX_LEN,
1326                                         dlm_convert_lock_handler,
1327                                         dlm, NULL, &dlm->dlm_domain_handlers);
1328         if (status)
1329                 goto bail;
1330
1331         status = o2net_register_handler(DLM_UNLOCK_LOCK_MSG, dlm->key,
1332                                         DLM_UNLOCK_LOCK_MAX_LEN,
1333                                         dlm_unlock_lock_handler,
1334                                         dlm, NULL, &dlm->dlm_domain_handlers);
1335         if (status)
1336                 goto bail;
1337
1338         status = o2net_register_handler(DLM_PROXY_AST_MSG, dlm->key,
1339                                         DLM_PROXY_AST_MAX_LEN,
1340                                         dlm_proxy_ast_handler,
1341                                         dlm, NULL, &dlm->dlm_domain_handlers);
1342         if (status)
1343                 goto bail;
1344
1345         status = o2net_register_handler(DLM_EXIT_DOMAIN_MSG, dlm->key,
1346                                         sizeof(struct dlm_exit_domain),
1347                                         dlm_exit_domain_handler,
1348                                         dlm, NULL, &dlm->dlm_domain_handlers);
1349         if (status)
1350                 goto bail;
1351
1352         status = o2net_register_handler(DLM_DEREF_LOCKRES_MSG, dlm->key,
1353                                         sizeof(struct dlm_deref_lockres),
1354                                         dlm_deref_lockres_handler,
1355                                         dlm, NULL, &dlm->dlm_domain_handlers);
1356         if (status)
1357                 goto bail;
1358
1359         status = o2net_register_handler(DLM_MIGRATE_REQUEST_MSG, dlm->key,
1360                                         sizeof(struct dlm_migrate_request),
1361                                         dlm_migrate_request_handler,
1362                                         dlm, NULL, &dlm->dlm_domain_handlers);
1363         if (status)
1364                 goto bail;
1365
1366         status = o2net_register_handler(DLM_MIG_LOCKRES_MSG, dlm->key,
1367                                         DLM_MIG_LOCKRES_MAX_LEN,
1368                                         dlm_mig_lockres_handler,
1369                                         dlm, NULL, &dlm->dlm_domain_handlers);
1370         if (status)
1371                 goto bail;
1372
1373         status = o2net_register_handler(DLM_MASTER_REQUERY_MSG, dlm->key,
1374                                         sizeof(struct dlm_master_requery),
1375                                         dlm_master_requery_handler,
1376                                         dlm, NULL, &dlm->dlm_domain_handlers);
1377         if (status)
1378                 goto bail;
1379
1380         status = o2net_register_handler(DLM_LOCK_REQUEST_MSG, dlm->key,
1381                                         sizeof(struct dlm_lock_request),
1382                                         dlm_request_all_locks_handler,
1383                                         dlm, NULL, &dlm->dlm_domain_handlers);
1384         if (status)
1385                 goto bail;
1386
1387         status = o2net_register_handler(DLM_RECO_DATA_DONE_MSG, dlm->key,
1388                                         sizeof(struct dlm_reco_data_done),
1389                                         dlm_reco_data_done_handler,
1390                                         dlm, NULL, &dlm->dlm_domain_handlers);
1391         if (status)
1392                 goto bail;
1393
1394         status = o2net_register_handler(DLM_BEGIN_RECO_MSG, dlm->key,
1395                                         sizeof(struct dlm_begin_reco),
1396                                         dlm_begin_reco_handler,
1397                                         dlm, NULL, &dlm->dlm_domain_handlers);
1398         if (status)
1399                 goto bail;
1400
1401         status = o2net_register_handler(DLM_FINALIZE_RECO_MSG, dlm->key,
1402                                         sizeof(struct dlm_finalize_reco),
1403                                         dlm_finalize_reco_handler,
1404                                         dlm, NULL, &dlm->dlm_domain_handlers);
1405         if (status)
1406                 goto bail;
1407
1408 bail:
1409         if (status)
1410                 dlm_unregister_domain_handlers(dlm);
1411
1412         return status;
1413 }
1414
1415 static int dlm_join_domain(struct dlm_ctxt *dlm)
1416 {
1417         int status;
1418         unsigned int backoff;
1419         unsigned int total_backoff = 0;
1420
1421         BUG_ON(!dlm);
1422
1423         mlog(0, "Join domain %s\n", dlm->name);
1424
1425         status = dlm_register_domain_handlers(dlm);
1426         if (status) {
1427                 mlog_errno(status);
1428                 goto bail;
1429         }
1430
1431         status = dlm_debug_init(dlm);
1432         if (status < 0) {
1433                 mlog_errno(status);
1434                 goto bail;
1435         }
1436
1437         status = dlm_launch_thread(dlm);
1438         if (status < 0) {
1439                 mlog_errno(status);
1440                 goto bail;
1441         }
1442
1443         status = dlm_launch_recovery_thread(dlm);
1444         if (status < 0) {
1445                 mlog_errno(status);
1446                 goto bail;
1447         }
1448
1449         dlm->dlm_worker = create_singlethread_workqueue("dlm_wq");
1450         if (!dlm->dlm_worker) {
1451                 status = -ENOMEM;
1452                 mlog_errno(status);
1453                 goto bail;
1454         }
1455
1456         do {
1457                 status = dlm_try_to_join_domain(dlm);
1458
1459                 /* If we're racing another node to the join, then we
1460                  * need to back off temporarily and let them
1461                  * complete. */
1462 #define DLM_JOIN_TIMEOUT_MSECS  90000
1463                 if (status == -EAGAIN) {
1464                         if (signal_pending(current)) {
1465                                 status = -ERESTARTSYS;
1466                                 goto bail;
1467                         }
1468
1469                         if (total_backoff >
1470                             msecs_to_jiffies(DLM_JOIN_TIMEOUT_MSECS)) {
1471                                 status = -ERESTARTSYS;
1472                                 mlog(ML_NOTICE, "Timed out joining dlm domain "
1473                                      "%s after %u msecs\n", dlm->name,
1474                                      jiffies_to_msecs(total_backoff));
1475                                 goto bail;
1476                         }
1477
1478                         /*
1479                          * <chip> After you!
1480                          * <dale> No, after you!
1481                          * <chip> I insist!
1482                          * <dale> But you first!
1483                          * ...
1484                          */
1485                         backoff = (unsigned int)(jiffies & 0x3);
1486                         backoff *= DLM_DOMAIN_BACKOFF_MS;
1487                         total_backoff += backoff;
1488                         mlog(0, "backoff %d\n", backoff);
1489                         msleep(backoff);
1490                 }
1491         } while (status == -EAGAIN);
1492
1493         if (status < 0) {
1494                 mlog_errno(status);
1495                 goto bail;
1496         }
1497
1498         status = 0;
1499 bail:
1500         wake_up(&dlm_domain_events);
1501
1502         if (status) {
1503                 dlm_unregister_domain_handlers(dlm);
1504                 dlm_debug_shutdown(dlm);
1505                 dlm_complete_thread(dlm);
1506                 dlm_complete_recovery_thread(dlm);
1507                 dlm_destroy_dlm_worker(dlm);
1508         }
1509
1510         return status;
1511 }
1512
1513 static struct dlm_ctxt *dlm_alloc_ctxt(const char *domain,
1514                                 u32 key)
1515 {
1516         int i;
1517         int ret;
1518         struct dlm_ctxt *dlm = NULL;
1519
1520         dlm = kzalloc(sizeof(*dlm), GFP_KERNEL);
1521         if (!dlm) {
1522                 mlog_errno(-ENOMEM);
1523                 goto leave;
1524         }
1525
1526         dlm->name = kstrdup(domain, GFP_KERNEL);
1527         if (dlm->name == NULL) {
1528                 mlog_errno(-ENOMEM);
1529                 kfree(dlm);
1530                 dlm = NULL;
1531                 goto leave;
1532         }
1533
1534         dlm->lockres_hash = (struct hlist_head **)dlm_alloc_pagevec(DLM_HASH_PAGES);
1535         if (!dlm->lockres_hash) {
1536                 mlog_errno(-ENOMEM);
1537                 kfree(dlm->name);
1538                 kfree(dlm);
1539                 dlm = NULL;
1540                 goto leave;
1541         }
1542
1543         for (i = 0; i < DLM_HASH_BUCKETS; i++)
1544                 INIT_HLIST_HEAD(dlm_lockres_hash(dlm, i));
1545
1546         dlm->master_hash = (struct hlist_head **)
1547                                 dlm_alloc_pagevec(DLM_HASH_PAGES);
1548         if (!dlm->master_hash) {
1549                 mlog_errno(-ENOMEM);
1550                 dlm_free_pagevec((void **)dlm->lockres_hash, DLM_HASH_PAGES);
1551                 kfree(dlm->name);
1552                 kfree(dlm);
1553                 dlm = NULL;
1554                 goto leave;
1555         }
1556
1557         for (i = 0; i < DLM_HASH_BUCKETS; i++)
1558                 INIT_HLIST_HEAD(dlm_master_hash(dlm, i));
1559
1560         dlm->key = key;
1561         dlm->node_num = o2nm_this_node();
1562
1563         ret = dlm_create_debugfs_subroot(dlm);
1564         if (ret < 0) {
1565                 dlm_free_pagevec((void **)dlm->master_hash, DLM_HASH_PAGES);
1566                 dlm_free_pagevec((void **)dlm->lockres_hash, DLM_HASH_PAGES);
1567                 kfree(dlm->name);
1568                 kfree(dlm);
1569                 dlm = NULL;
1570                 goto leave;
1571         }
1572
1573         spin_lock_init(&dlm->spinlock);
1574         spin_lock_init(&dlm->master_lock);
1575         spin_lock_init(&dlm->ast_lock);
1576         spin_lock_init(&dlm->track_lock);
1577         INIT_LIST_HEAD(&dlm->list);
1578         INIT_LIST_HEAD(&dlm->dirty_list);
1579         INIT_LIST_HEAD(&dlm->reco.resources);
1580         INIT_LIST_HEAD(&dlm->reco.received);
1581         INIT_LIST_HEAD(&dlm->reco.node_data);
1582         INIT_LIST_HEAD(&dlm->purge_list);
1583         INIT_LIST_HEAD(&dlm->dlm_domain_handlers);
1584         INIT_LIST_HEAD(&dlm->tracking_list);
1585         dlm->reco.state = 0;
1586
1587         INIT_LIST_HEAD(&dlm->pending_asts);
1588         INIT_LIST_HEAD(&dlm->pending_basts);
1589
1590         mlog(0, "dlm->recovery_map=%p, &(dlm->recovery_map[0])=%p\n",
1591                   dlm->recovery_map, &(dlm->recovery_map[0]));
1592
1593         memset(dlm->recovery_map, 0, sizeof(dlm->recovery_map));
1594         memset(dlm->live_nodes_map, 0, sizeof(dlm->live_nodes_map));
1595         memset(dlm->domain_map, 0, sizeof(dlm->domain_map));
1596
1597         dlm->dlm_thread_task = NULL;
1598         dlm->dlm_reco_thread_task = NULL;
1599         dlm->dlm_worker = NULL;
1600         init_waitqueue_head(&dlm->dlm_thread_wq);
1601         init_waitqueue_head(&dlm->dlm_reco_thread_wq);
1602         init_waitqueue_head(&dlm->reco.event);
1603         init_waitqueue_head(&dlm->ast_wq);
1604         init_waitqueue_head(&dlm->migration_wq);
1605         INIT_LIST_HEAD(&dlm->mle_hb_events);
1606
1607         dlm->joining_node = DLM_LOCK_RES_OWNER_UNKNOWN;
1608         init_waitqueue_head(&dlm->dlm_join_events);
1609
1610         dlm->reco.new_master = O2NM_INVALID_NODE_NUM;
1611         dlm->reco.dead_node = O2NM_INVALID_NODE_NUM;
1612
1613         atomic_set(&dlm->res_tot_count, 0);
1614         atomic_set(&dlm->res_cur_count, 0);
1615         for (i = 0; i < DLM_MLE_NUM_TYPES; ++i) {
1616                 atomic_set(&dlm->mle_tot_count[i], 0);
1617                 atomic_set(&dlm->mle_cur_count[i], 0);
1618         }
1619
1620         spin_lock_init(&dlm->work_lock);
1621         INIT_LIST_HEAD(&dlm->work_list);
1622         INIT_WORK(&dlm->dispatched_work, dlm_dispatch_work);
1623
1624         kref_init(&dlm->dlm_refs);
1625         dlm->dlm_state = DLM_CTXT_NEW;
1626
1627         INIT_LIST_HEAD(&dlm->dlm_eviction_callbacks);
1628
1629         mlog(0, "context init: refcount %u\n",
1630                   atomic_read(&dlm->dlm_refs.refcount));
1631
1632 leave:
1633         return dlm;
1634 }
1635
1636 /*
1637  * Compare a requested locking protocol version against the current one.
1638  *
1639  * If the major numbers are different, they are incompatible.
1640  * If the current minor is greater than the request, they are incompatible.
1641  * If the current minor is less than or equal to the request, they are
1642  * compatible, and the requester should run at the current minor version.
1643  */
1644 static int dlm_protocol_compare(struct dlm_protocol_version *existing,
1645                                 struct dlm_protocol_version *request)
1646 {
1647         if (existing->pv_major != request->pv_major)
1648                 return 1;
1649
1650         if (existing->pv_minor > request->pv_minor)
1651                 return 1;
1652
1653         if (existing->pv_minor < request->pv_minor)
1654                 request->pv_minor = existing->pv_minor;
1655
1656         return 0;
1657 }
1658
1659 /*
1660  * dlm_register_domain: one-time setup per "domain".
1661  *
1662  * The filesystem passes in the requested locking version via proto.
1663  * If registration was successful, proto will contain the negotiated
1664  * locking protocol.
1665  */
1666 struct dlm_ctxt * dlm_register_domain(const char *domain,
1667                                u32 key,
1668                                struct dlm_protocol_version *fs_proto)
1669 {
1670         int ret;
1671         struct dlm_ctxt *dlm = NULL;
1672         struct dlm_ctxt *new_ctxt = NULL;
1673
1674         if (strlen(domain) > O2NM_MAX_NAME_LEN) {
1675                 ret = -ENAMETOOLONG;
1676                 mlog(ML_ERROR, "domain name length too long\n");
1677                 goto leave;
1678         }
1679
1680         if (!o2hb_check_local_node_heartbeating()) {
1681                 mlog(ML_ERROR, "the local node has not been configured, or is "
1682                      "not heartbeating\n");
1683                 ret = -EPROTO;
1684                 goto leave;
1685         }
1686
1687         mlog(0, "register called for domain \"%s\"\n", domain);
1688
1689 retry:
1690         dlm = NULL;
1691         if (signal_pending(current)) {
1692                 ret = -ERESTARTSYS;
1693                 mlog_errno(ret);
1694                 goto leave;
1695         }
1696
1697         spin_lock(&dlm_domain_lock);
1698
1699         dlm = __dlm_lookup_domain(domain);
1700         if (dlm) {
1701                 if (dlm->dlm_state != DLM_CTXT_JOINED) {
1702                         spin_unlock(&dlm_domain_lock);
1703
1704                         mlog(0, "This ctxt is not joined yet!\n");
1705                         wait_event_interruptible(dlm_domain_events,
1706                                                  dlm_wait_on_domain_helper(
1707                                                          domain));
1708                         goto retry;
1709                 }
1710
1711                 if (dlm_protocol_compare(&dlm->fs_locking_proto, fs_proto)) {
1712                         mlog(ML_ERROR,
1713                              "Requested locking protocol version is not "
1714                              "compatible with already registered domain "
1715                              "\"%s\"\n", domain);
1716                         ret = -EPROTO;
1717                         goto leave;
1718                 }
1719
1720                 __dlm_get(dlm);
1721                 dlm->num_joins++;
1722
1723                 spin_unlock(&dlm_domain_lock);
1724
1725                 ret = 0;
1726                 goto leave;
1727         }
1728
1729         /* doesn't exist */
1730         if (!new_ctxt) {
1731                 spin_unlock(&dlm_domain_lock);
1732
1733                 new_ctxt = dlm_alloc_ctxt(domain, key);
1734                 if (new_ctxt)
1735                         goto retry;
1736
1737                 ret = -ENOMEM;
1738                 mlog_errno(ret);
1739                 goto leave;
1740         }
1741
1742         /* a little variable switch-a-roo here... */
1743         dlm = new_ctxt;
1744         new_ctxt = NULL;
1745
1746         /* add the new domain */
1747         list_add_tail(&dlm->list, &dlm_domains);
1748         spin_unlock(&dlm_domain_lock);
1749
1750         /*
1751          * Pass the locking protocol version into the join.  If the join
1752          * succeeds, it will have the negotiated protocol set.
1753          */
1754         dlm->dlm_locking_proto = dlm_protocol;
1755         dlm->fs_locking_proto = *fs_proto;
1756
1757         ret = dlm_join_domain(dlm);
1758         if (ret) {
1759                 mlog_errno(ret);
1760                 dlm_put(dlm);
1761                 goto leave;
1762         }
1763
1764         /* Tell the caller what locking protocol we negotiated */
1765         *fs_proto = dlm->fs_locking_proto;
1766
1767         ret = 0;
1768 leave:
1769         if (new_ctxt)
1770                 dlm_free_ctxt_mem(new_ctxt);
1771
1772         if (ret < 0)
1773                 dlm = ERR_PTR(ret);
1774
1775         return dlm;
1776 }
1777 EXPORT_SYMBOL_GPL(dlm_register_domain);
1778
1779 static LIST_HEAD(dlm_join_handlers);
1780
1781 static void dlm_unregister_net_handlers(void)
1782 {
1783         o2net_unregister_handler_list(&dlm_join_handlers);
1784 }
1785
1786 static int dlm_register_net_handlers(void)
1787 {
1788         int status = 0;
1789
1790         status = o2net_register_handler(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY,
1791                                         sizeof(struct dlm_query_join_request),
1792                                         dlm_query_join_handler,
1793                                         NULL, NULL, &dlm_join_handlers);
1794         if (status)
1795                 goto bail;
1796
1797         status = o2net_register_handler(DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
1798                                         sizeof(struct dlm_assert_joined),
1799                                         dlm_assert_joined_handler,
1800                                         NULL, NULL, &dlm_join_handlers);
1801         if (status)
1802                 goto bail;
1803
1804         status = o2net_register_handler(DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
1805                                         sizeof(struct dlm_cancel_join),
1806                                         dlm_cancel_join_handler,
1807                                         NULL, NULL, &dlm_join_handlers);
1808
1809 bail:
1810         if (status < 0)
1811                 dlm_unregister_net_handlers();
1812
1813         return status;
1814 }
1815
1816 /* Domain eviction callback handling.
1817  *
1818  * The file system requires notification of node death *before* the
1819  * dlm completes it's recovery work, otherwise it may be able to
1820  * acquire locks on resources requiring recovery. Since the dlm can
1821  * evict a node from it's domain *before* heartbeat fires, a similar
1822  * mechanism is required. */
1823
1824 /* Eviction is not expected to happen often, so a per-domain lock is
1825  * not necessary. Eviction callbacks are allowed to sleep for short
1826  * periods of time. */
1827 static DECLARE_RWSEM(dlm_callback_sem);
1828
1829 void dlm_fire_domain_eviction_callbacks(struct dlm_ctxt *dlm,
1830                                         int node_num)
1831 {
1832         struct list_head *iter;
1833         struct dlm_eviction_cb *cb;
1834
1835         down_read(&dlm_callback_sem);
1836         list_for_each(iter, &dlm->dlm_eviction_callbacks) {
1837                 cb = list_entry(iter, struct dlm_eviction_cb, ec_item);
1838
1839                 cb->ec_func(node_num, cb->ec_data);
1840         }
1841         up_read(&dlm_callback_sem);
1842 }
1843
1844 void dlm_setup_eviction_cb(struct dlm_eviction_cb *cb,
1845                            dlm_eviction_func *f,
1846                            void *data)
1847 {
1848         INIT_LIST_HEAD(&cb->ec_item);
1849         cb->ec_func = f;
1850         cb->ec_data = data;
1851 }
1852 EXPORT_SYMBOL_GPL(dlm_setup_eviction_cb);
1853
1854 void dlm_register_eviction_cb(struct dlm_ctxt *dlm,
1855                               struct dlm_eviction_cb *cb)
1856 {
1857         down_write(&dlm_callback_sem);
1858         list_add_tail(&cb->ec_item, &dlm->dlm_eviction_callbacks);
1859         up_write(&dlm_callback_sem);
1860 }
1861 EXPORT_SYMBOL_GPL(dlm_register_eviction_cb);
1862
1863 void dlm_unregister_eviction_cb(struct dlm_eviction_cb *cb)
1864 {
1865         down_write(&dlm_callback_sem);
1866         list_del_init(&cb->ec_item);
1867         up_write(&dlm_callback_sem);
1868 }
1869 EXPORT_SYMBOL_GPL(dlm_unregister_eviction_cb);
1870
1871 static int __init dlm_init(void)
1872 {
1873         int status;
1874
1875         dlm_print_version();
1876
1877         status = dlm_init_mle_cache();
1878         if (status) {
1879                 mlog(ML_ERROR, "Could not create o2dlm_mle slabcache\n");
1880                 goto error;
1881         }
1882
1883         status = dlm_init_master_caches();
1884         if (status) {
1885                 mlog(ML_ERROR, "Could not create o2dlm_lockres and "
1886                      "o2dlm_lockname slabcaches\n");
1887                 goto error;
1888         }
1889
1890         status = dlm_init_lock_cache();
1891         if (status) {
1892                 mlog(ML_ERROR, "Count not create o2dlm_lock slabcache\n");
1893                 goto error;
1894         }
1895
1896         status = dlm_register_net_handlers();
1897         if (status) {
1898                 mlog(ML_ERROR, "Unable to register network handlers\n");
1899                 goto error;
1900         }
1901
1902         status = dlm_create_debugfs_root();
1903         if (status)
1904                 goto error;
1905
1906         return 0;
1907 error:
1908         dlm_unregister_net_handlers();
1909         dlm_destroy_lock_cache();
1910         dlm_destroy_master_caches();
1911         dlm_destroy_mle_cache();
1912         return -1;
1913 }
1914
1915 static void __exit dlm_exit (void)
1916 {
1917         dlm_destroy_debugfs_root();
1918         dlm_unregister_net_handlers();
1919         dlm_destroy_lock_cache();
1920         dlm_destroy_master_caches();
1921         dlm_destroy_mle_cache();
1922 }
1923
1924 MODULE_AUTHOR("Oracle");
1925 MODULE_LICENSE("GPL");
1926
1927 module_init(dlm_init);
1928 module_exit(dlm_exit);