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 /*
  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 #define DLM_DOMAIN_BACKOFF_MS 200
 127
 128 static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
 129                                   void **ret_data);
 130 static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data,
 131                                      void **ret_data);
 132 static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data,
 133                                    void **ret_data);
 134 static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data,
 135                                    void **ret_data);
 136
 137 static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm);
 138
 139 void __dlm_unhash_lockres(struct dlm_lock_resource *lockres)
 140 {
 141         if (!hlist_unhashed(&lockres->hash_node)) {
 142                 hlist_del_init(&lockres->hash_node);
 143                 dlm_lockres_put(lockres);
 144         }
 145 }
 146
 147 void __dlm_insert_lockres(struct dlm_ctxt *dlm,
 148                        struct dlm_lock_resource *res)
 149 {
 150         struct hlist_head *bucket;
 151         struct qstr *q;
 152
 153         assert_spin_locked(&dlm->spinlock);
 154
 155         q = &res->lockname;
 156         bucket = dlm_lockres_hash(dlm, q->hash);
 157
 158         /* get a reference for our hashtable */
 159         dlm_lockres_get(res);
 160
 161         hlist_add_head(&res->hash_node, bucket);
 162 }
 163
 164 struct dlm_lock_resource * __dlm_lookup_lockres_full(struct dlm_ctxt *dlm,
 165                                                      const char *name,
 166                                                      unsigned int len,
 167                                                      unsigned int hash)
 168 {
 169         struct hlist_head *bucket;
 170         struct hlist_node *list;
 171
 172         mlog_entry("%.*s\n", len, name);
 173
 174         assert_spin_locked(&dlm->spinlock);
 175
 176         bucket = dlm_lockres_hash(dlm, hash);
 177
 178         hlist_for_each(list, bucket) {
 179                 struct dlm_lock_resource *res = hlist_entry(list,
 180                         struct dlm_lock_resource, hash_node);
 181                 if (res->lockname.name[0] != name[0])
 182                         continue;
 183                 if (unlikely(res->lockname.len != len))
 184                         continue;
 185                 if (memcmp(res->lockname.name + 1, name + 1, len - 1))
 186                         continue;
 187                 dlm_lockres_get(res);
 188                 return res;
 189         }
 190         return NULL;
 191 }
 192
 193 /* intended to be called by functions which do not care about lock
 194  * resources which are being purged (most net _handler functions).
 195  * this will return NULL for any lock resource which is found but
 196  * currently in the process of dropping its mastery reference.
 197  * use __dlm_lookup_lockres_full when you need the lock resource
 198  * regardless (e.g. dlm_get_lock_resource) */
 199 struct dlm_lock_resource * __dlm_lookup_lockres(struct dlm_ctxt *dlm,
 200                                                 const char *name,
 201                                                 unsigned int len,
 202                                                 unsigned int hash)
 203 {
 204         struct dlm_lock_resource *res = NULL;
 205
 206         mlog_entry("%.*s\n", len, name);
 207
 208         assert_spin_locked(&dlm->spinlock);
 209
 210         res = __dlm_lookup_lockres_full(dlm, name, len, hash);
 211         if (res) {
 212                 spin_lock(&res->spinlock);
 213                 if (res->state & DLM_LOCK_RES_DROPPING_REF) {
 214                         spin_unlock(&res->spinlock);
 215                         dlm_lockres_put(res);
 216                         return NULL;
 217                 }
 218                 spin_unlock(&res->spinlock);
 219         }
 220
 221         return res;
 222 }
 223
 224 struct dlm_lock_resource * dlm_lookup_lockres(struct dlm_ctxt *dlm,
 225                                     const char *name,
 226                                     unsigned int len)
 227 {
 228         struct dlm_lock_resource *res;
 229         unsigned int hash = dlm_lockid_hash(name, len);
 230
 231         spin_lock(&dlm->spinlock);
 232         res = __dlm_lookup_lockres(dlm, name, len, hash);
 233         spin_unlock(&dlm->spinlock);
 234         return res;
 235 }
 236
 237 static struct dlm_ctxt * __dlm_lookup_domain_full(const char *domain, int len)
 238 {
 239         struct dlm_ctxt *tmp = NULL;
 240         struct list_head *iter;
 241
 242         assert_spin_locked(&dlm_domain_lock);
 243
 244         /* tmp->name here is always NULL terminated,
 245          * but domain may not be! */
 246         list_for_each(iter, &dlm_domains) {
 247                 tmp = list_entry (iter, struct dlm_ctxt, list);
 248                 if (strlen(tmp->name) == len &&
 249                     memcmp(tmp->name, domain, len)==0)
 250                         break;
 251                 tmp = NULL;
 252         }
 253
 254         return tmp;
 255 }
 256
 257 /* For null terminated domain strings ONLY */
 258 static struct dlm_ctxt * __dlm_lookup_domain(const char *domain)
 259 {
 260         assert_spin_locked(&dlm_domain_lock);
 261
 262         return __dlm_lookup_domain_full(domain, strlen(domain));
 263 }
 264
 265
 266 /* returns true on one of two conditions:
 267  * 1) the domain does not exist
 268  * 2) the domain exists and it's state is "joined" */
 269 static int dlm_wait_on_domain_helper(const char *domain)
 270 {
 271         int ret = 0;
 272         struct dlm_ctxt *tmp = NULL;
 273
 274         spin_lock(&dlm_domain_lock);
 275
 276         tmp = __dlm_lookup_domain(domain);
 277         if (!tmp)
 278                 ret = 1;
 279         else if (tmp->dlm_state == DLM_CTXT_JOINED)
 280                 ret = 1;
 281
 282         spin_unlock(&dlm_domain_lock);
 283         return ret;
 284 }
 285
 286 static void dlm_free_ctxt_mem(struct dlm_ctxt *dlm)
 287 {
 288         if (dlm->lockres_hash)
 289                 dlm_free_pagevec((void **)dlm->lockres_hash, DLM_HASH_PAGES);
 290
 291         if (dlm->name)
 292                 kfree(dlm->name);
 293
 294         kfree(dlm);
 295 }
 296
 297 /* A little strange - this function will be called while holding
 298  * dlm_domain_lock and is expected to be holding it on the way out. We
 299  * will however drop and reacquire it multiple times */
 300 static void dlm_ctxt_release(struct kref *kref)
 301 {
 302         struct dlm_ctxt *dlm;
 303
 304         dlm = container_of(kref, struct dlm_ctxt, dlm_refs);
 305
 306         BUG_ON(dlm->num_joins);
 307         BUG_ON(dlm->dlm_state == DLM_CTXT_JOINED);
 308
 309         /* we may still be in the list if we hit an error during join. */
 310         list_del_init(&dlm->list);
 311
 312         spin_unlock(&dlm_domain_lock);
 313
 314         mlog(0, "freeing memory from domain %s\n", dlm->name);
 315
 316         wake_up(&dlm_domain_events);
 317
 318         dlm_free_ctxt_mem(dlm);
 319
 320         spin_lock(&dlm_domain_lock);
 321 }
 322
 323 void dlm_put(struct dlm_ctxt *dlm)
 324 {
 325         spin_lock(&dlm_domain_lock);
 326         kref_put(&dlm->dlm_refs, dlm_ctxt_release);
 327         spin_unlock(&dlm_domain_lock);
 328 }
 329
 330 static void __dlm_get(struct dlm_ctxt *dlm)
 331 {
 332         kref_get(&dlm->dlm_refs);
 333 }
 334
 335 /* given a questionable reference to a dlm object, gets a reference if
 336  * it can find it in the list, otherwise returns NULL in which case
 337  * you shouldn't trust your pointer. */
 338 struct dlm_ctxt *dlm_grab(struct dlm_ctxt *dlm)
 339 {
 340         struct list_head *iter;
 341         struct dlm_ctxt *target = NULL;
 342
 343         spin_lock(&dlm_domain_lock);
 344
 345         list_for_each(iter, &dlm_domains) {
 346                 target = list_entry (iter, struct dlm_ctxt, list);
 347
 348                 if (target == dlm) {
 349                         __dlm_get(target);
 350                         break;
 351                 }
 352
 353                 target = NULL;
 354         }
 355
 356         spin_unlock(&dlm_domain_lock);
 357
 358         return target;
 359 }
 360
 361 int dlm_domain_fully_joined(struct dlm_ctxt *dlm)
 362 {
 363         int ret;
 364
 365         spin_lock(&dlm_domain_lock);
 366         ret = (dlm->dlm_state == DLM_CTXT_JOINED) ||
 367                 (dlm->dlm_state == DLM_CTXT_IN_SHUTDOWN);
 368         spin_unlock(&dlm_domain_lock);
 369
 370         return ret;
 371 }
 372
 373 static void dlm_destroy_dlm_worker(struct dlm_ctxt *dlm)
 374 {
 375         if (dlm->dlm_worker) {
 376                 flush_workqueue(dlm->dlm_worker);
 377                 destroy_workqueue(dlm->dlm_worker);
 378                 dlm->dlm_worker = NULL;
 379         }
 380 }
 381
 382 static void dlm_complete_dlm_shutdown(struct dlm_ctxt *dlm)
 383 {
 384         dlm_unregister_domain_handlers(dlm);
 385         dlm_complete_thread(dlm);
 386         dlm_complete_recovery_thread(dlm);
 387         dlm_destroy_dlm_worker(dlm);
 388
 389         /* We've left the domain. Now we can take ourselves out of the
 390          * list and allow the kref stuff to help us free the
 391          * memory. */
 392         spin_lock(&dlm_domain_lock);
 393         list_del_init(&dlm->list);
 394         spin_unlock(&dlm_domain_lock);
 395
 396         /* Wake up anyone waiting for us to remove this domain */
 397         wake_up(&dlm_domain_events);
 398 }
 399
 400 static int dlm_migrate_all_locks(struct dlm_ctxt *dlm)
 401 {
 402         int i, num, n, ret = 0;
 403         struct dlm_lock_resource *res;
 404         struct hlist_node *iter;
 405         struct hlist_head *bucket;
 406         int dropped;
 407
 408         mlog(0, "Migrating locks from domain %s\n", dlm->name);
 409
 410         num = 0;
 411         spin_lock(&dlm->spinlock);
 412         for (i = 0; i < DLM_HASH_BUCKETS; i++) {
 413 redo_bucket:
 414                 n = 0;
 415                 bucket = dlm_lockres_hash(dlm, i);
 416                 iter = bucket->first;
 417                 while (iter) {
 418                         n++;
 419                         res = hlist_entry(iter, struct dlm_lock_resource,
 420                                           hash_node);
 421                         dlm_lockres_get(res);
 422                         /* migrate, if necessary.  this will drop the dlm
 423                          * spinlock and retake it if it does migration. */
 424                         dropped = dlm_empty_lockres(dlm, res);
 425
 426                         spin_lock(&res->spinlock);
 427                         __dlm_lockres_calc_usage(dlm, res);
 428                         iter = res->hash_node.next;
 429                         spin_unlock(&res->spinlock);
 430
 431                         dlm_lockres_put(res);
 432
 433                         cond_resched_lock(&dlm->spinlock);
 434
 435                         if (dropped)
 436                                 goto redo_bucket;
 437                 }
 438                 num += n;
 439                 mlog(0, "%s: touched %d lockreses in bucket %d "
 440                      "(tot=%d)\n", dlm->name, n, i, num);
 441         }
 442         spin_unlock(&dlm->spinlock);
 443         wake_up(&dlm->dlm_thread_wq);
 444
 445         /* let the dlm thread take care of purging, keep scanning until
 446          * nothing remains in the hash */
 447         if (num) {
 448                 mlog(0, "%s: %d lock resources in hash last pass\n",
 449                      dlm->name, num);
 450                 ret = -EAGAIN;
 451         }
 452         mlog(0, "DONE Migrating locks from domain %s\n", dlm->name);
 453         return ret;
 454 }
 455
 456 static int dlm_no_joining_node(struct dlm_ctxt *dlm)
 457 {
 458         int ret;
 459
 460         spin_lock(&dlm->spinlock);
 461         ret = dlm->joining_node == DLM_LOCK_RES_OWNER_UNKNOWN;
 462         spin_unlock(&dlm->spinlock);
 463
 464         return ret;
 465 }
 466
 467 static void dlm_mark_domain_leaving(struct dlm_ctxt *dlm)
 468 {
 469         /* Yikes, a double spinlock! I need domain_lock for the dlm
 470          * state and the dlm spinlock for join state... Sorry! */
 471 again:
 472         spin_lock(&dlm_domain_lock);
 473         spin_lock(&dlm->spinlock);
 474
 475         if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
 476                 mlog(0, "Node %d is joining, we wait on it.\n",
 477                           dlm->joining_node);
 478                 spin_unlock(&dlm->spinlock);
 479                 spin_unlock(&dlm_domain_lock);
 480
 481                 wait_event(dlm->dlm_join_events, dlm_no_joining_node(dlm));
 482                 goto again;
 483         }
 484
 485         dlm->dlm_state = DLM_CTXT_LEAVING;
 486         spin_unlock(&dlm->spinlock);
 487         spin_unlock(&dlm_domain_lock);
 488 }
 489
 490 static void __dlm_print_nodes(struct dlm_ctxt *dlm)
 491 {
 492         int node = -1;
 493
 494         assert_spin_locked(&dlm->spinlock);
 495
 496         printk(KERN_INFO "ocfs2_dlm: Nodes in domain (\"%s\"): ", dlm->name);
 497
 498         while ((node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES,
 499                                      node + 1)) < O2NM_MAX_NODES) {
 500                 printk("%d ", node);
 501         }
 502         printk("\n");
 503 }
 504
 505 static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data,
 506                                    void **ret_data)
 507 {
 508         struct dlm_ctxt *dlm = data;
 509         unsigned int node;
 510         struct dlm_exit_domain *exit_msg = (struct dlm_exit_domain *) msg->buf;
 511
 512         mlog_entry("%p %u %p", msg, len, data);
 513
 514         if (!dlm_grab(dlm))
 515                 return 0;
 516
 517         node = exit_msg->node_idx;
 518
 519         printk(KERN_INFO "ocfs2_dlm: Node %u leaves domain %s\n", node, dlm->name);
 520
 521         spin_lock(&dlm->spinlock);
 522         clear_bit(node, dlm->domain_map);
 523         __dlm_print_nodes(dlm);
 524
 525         /* notify anything attached to the heartbeat events */
 526         dlm_hb_event_notify_attached(dlm, node, 0);
 527
 528         spin_unlock(&dlm->spinlock);
 529
 530         dlm_put(dlm);
 531
 532         return 0;
 533 }
 534
 535 static int dlm_send_one_domain_exit(struct dlm_ctxt *dlm,
 536                                     unsigned int node)
 537 {
 538         int status;
 539         struct dlm_exit_domain leave_msg;
 540
 541         mlog(0, "Asking node %u if we can leave the domain %s me = %u\n",
 542                   node, dlm->name, dlm->node_num);
 543
 544         memset(&leave_msg, 0, sizeof(leave_msg));
 545         leave_msg.node_idx = dlm->node_num;
 546
 547         status = o2net_send_message(DLM_EXIT_DOMAIN_MSG, dlm->key,
 548                                     &leave_msg, sizeof(leave_msg), node,
 549                                     NULL);
 550
 551         mlog(0, "status return %d from o2net_send_message\n", status);
 552
 553         return status;
 554 }
 555
 556
 557 static void dlm_leave_domain(struct dlm_ctxt *dlm)
 558 {
 559         int node, clear_node, status;
 560
 561         /* At this point we've migrated away all our locks and won't
 562          * accept mastership of new ones. The dlm is responsible for
 563          * almost nothing now. We make sure not to confuse any joining
 564          * nodes and then commence shutdown procedure. */
 565
 566         spin_lock(&dlm->spinlock);
 567         /* Clear ourselves from the domain map */
 568         clear_bit(dlm->node_num, dlm->domain_map);
 569         while ((node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES,
 570                                      0)) < O2NM_MAX_NODES) {
 571                 /* Drop the dlm spinlock. This is safe wrt the domain_map.
 572                  * -nodes cannot be added now as the
 573                  *   query_join_handlers knows to respond with OK_NO_MAP
 574                  * -we catch the right network errors if a node is
 575                  *   removed from the map while we're sending him the
 576                  *   exit message. */
 577                 spin_unlock(&dlm->spinlock);
 578
 579                 clear_node = 1;
 580
 581                 status = dlm_send_one_domain_exit(dlm, node);
 582                 if (status < 0 &&
 583                     status != -ENOPROTOOPT &&
 584                     status != -ENOTCONN) {
 585                         mlog(ML_NOTICE, "Error %d sending domain exit message "
 586                              "to node %d\n", status, node);
 587
 588                         /* Not sure what to do here but lets sleep for
 589                          * a bit in case this was a transient
 590                          * error... */
 591                         msleep(DLM_DOMAIN_BACKOFF_MS);
 592                         clear_node = 0;
 593                 }
 594
 595                 spin_lock(&dlm->spinlock);
 596                 /* If we're not clearing the node bit then we intend
 597                  * to loop back around to try again. */
 598                 if (clear_node)
 599                         clear_bit(node, dlm->domain_map);
 600         }
 601         spin_unlock(&dlm->spinlock);
 602 }
 603
 604 int dlm_joined(struct dlm_ctxt *dlm)
 605 {
 606         int ret = 0;
 607
 608         spin_lock(&dlm_domain_lock);
 609
 610         if (dlm->dlm_state == DLM_CTXT_JOINED)
 611                 ret = 1;
 612
 613         spin_unlock(&dlm_domain_lock);
 614
 615         return ret;
 616 }
 617
 618 int dlm_shutting_down(struct dlm_ctxt *dlm)
 619 {
 620         int ret = 0;
 621
 622         spin_lock(&dlm_domain_lock);
 623
 624         if (dlm->dlm_state == DLM_CTXT_IN_SHUTDOWN)
 625                 ret = 1;
 626
 627         spin_unlock(&dlm_domain_lock);
 628
 629         return ret;
 630 }
 631
 632 void dlm_unregister_domain(struct dlm_ctxt *dlm)
 633 {
 634         int leave = 0;
 635
 636         spin_lock(&dlm_domain_lock);
 637         BUG_ON(dlm->dlm_state != DLM_CTXT_JOINED);
 638         BUG_ON(!dlm->num_joins);
 639
 640         dlm->num_joins--;
 641         if (!dlm->num_joins) {
 642                 /* We mark it "in shutdown" now so new register
 643                  * requests wait until we've completely left the
 644                  * domain. Don't use DLM_CTXT_LEAVING yet as we still
 645                  * want new domain joins to communicate with us at
 646                  * least until we've completed migration of our
 647                  * resources. */
 648                 dlm->dlm_state = DLM_CTXT_IN_SHUTDOWN;
 649                 leave = 1;
 650         }
 651         spin_unlock(&dlm_domain_lock);
 652
 653         if (leave) {
 654                 mlog(0, "shutting down domain %s\n", dlm->name);
 655
 656                 /* We changed dlm state, notify the thread */
 657                 dlm_kick_thread(dlm, NULL);
 658
 659                 while (dlm_migrate_all_locks(dlm)) {
 660                         mlog(0, "%s: more migration to do\n", dlm->name);
 661                 }
 662                 dlm_mark_domain_leaving(dlm);
 663                 dlm_leave_domain(dlm);
 664                 dlm_complete_dlm_shutdown(dlm);
 665         }
 666         dlm_put(dlm);
 667 }
 668 EXPORT_SYMBOL_GPL(dlm_unregister_domain);
 669
 670 static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
 671                                   void **ret_data)
 672 {
 673         struct dlm_query_join_request *query;
 674         enum dlm_query_join_response response;
 675         struct dlm_ctxt *dlm = NULL;
 676         u8 nodenum;
 677
 678         query = (struct dlm_query_join_request *) msg->buf;
 679
 680         mlog(0, "node %u wants to join domain %s\n", query->node_idx,
 681                   query->domain);
 682
 683         /*
 684          * If heartbeat doesn't consider the node live, tell it
 685          * to back off and try again.  This gives heartbeat a chance
 686          * to catch up.
 687          */
 688         if (!o2hb_check_node_heartbeating(query->node_idx)) {
 689                 mlog(0, "node %u is not in our live map yet\n",
 690                      query->node_idx);
 691
 692                 response = JOIN_DISALLOW;
 693                 goto respond;
 694         }
 695
 696         response = JOIN_OK_NO_MAP;
 697
 698         spin_lock(&dlm_domain_lock);
 699         dlm = __dlm_lookup_domain_full(query->domain, query->name_len);
 700         if (!dlm)
 701                 goto unlock_respond;
 702
 703         /*
 704          * There is a small window where the joining node may not see the
 705          * node(s) that just left but still part of the cluster. DISALLOW
 706          * join request if joining node has different node map.
 707          */
 708         nodenum=0;
 709         while (nodenum < O2NM_MAX_NODES) {
 710                 if (test_bit(nodenum, dlm->domain_map)) {
 711                         if (!byte_test_bit(nodenum, query->node_map)) {
 712                                 mlog(0, "disallow join as node %u does not "
 713                                      "have node %u in its nodemap\n",
 714                                      query->node_idx, nodenum);
 715                                 response = JOIN_DISALLOW;
 716                                 goto unlock_respond;
 717                         }
 718                 }
 719                 nodenum++;
 720         }
 721
 722         /* Once the dlm ctxt is marked as leaving then we don't want
 723          * to be put in someone's domain map.
 724          * Also, explicitly disallow joining at certain troublesome
 725          * times (ie. during recovery). */
 726         if (dlm && dlm->dlm_state != DLM_CTXT_LEAVING) {
 727                 int bit = query->node_idx;
 728                 spin_lock(&dlm->spinlock);
 729
 730                 if (dlm->dlm_state == DLM_CTXT_NEW &&
 731                     dlm->joining_node == DLM_LOCK_RES_OWNER_UNKNOWN) {
 732                         /*If this is a brand new context and we
 733                          * haven't started our join process yet, then
 734                          * the other node won the race. */
 735                         response = JOIN_OK_NO_MAP;
 736                 } else if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
 737                         /* Disallow parallel joins. */
 738                         response = JOIN_DISALLOW;
 739                 } else if (dlm->reco.state & DLM_RECO_STATE_ACTIVE) {
 740                         mlog(0, "node %u trying to join, but recovery "
 741                              "is ongoing.\n", bit);
 742                         response = JOIN_DISALLOW;
 743                 } else if (test_bit(bit, dlm->recovery_map)) {
 744                         mlog(0, "node %u trying to join, but it "
 745                              "still needs recovery.\n", bit);
 746                         response = JOIN_DISALLOW;
 747                 } else if (test_bit(bit, dlm->domain_map)) {
 748                         mlog(0, "node %u trying to join, but it "
 749                              "is still in the domain! needs recovery?\n",
 750                              bit);
 751                         response = JOIN_DISALLOW;
 752                 } else {
 753                         /* Alright we're fully a part of this domain
 754                          * so we keep some state as to who's joining
 755                          * and indicate to him that needs to be fixed
 756                          * up. */
 757                         response = JOIN_OK;
 758                         __dlm_set_joining_node(dlm, query->node_idx);
 759                 }
 760
 761                 spin_unlock(&dlm->spinlock);
 762         }
 763 unlock_respond:
 764         spin_unlock(&dlm_domain_lock);
 765
 766 respond:
 767         mlog(0, "We respond with %u\n", response);
 768
 769         return response;
 770 }
 771
 772 static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data,
 773                                      void **ret_data)
 774 {
 775         struct dlm_assert_joined *assert;
 776         struct dlm_ctxt *dlm = NULL;
 777
 778         assert = (struct dlm_assert_joined *) msg->buf;
 779
 780         mlog(0, "node %u asserts join on domain %s\n", assert->node_idx,
 781                   assert->domain);
 782
 783         spin_lock(&dlm_domain_lock);
 784         dlm = __dlm_lookup_domain_full(assert->domain, assert->name_len);
 785         /* XXX should we consider no dlm ctxt an error? */
 786         if (dlm) {
 787                 spin_lock(&dlm->spinlock);
 788
 789                 /* Alright, this node has officially joined our
 790                  * domain. Set him in the map and clean up our
 791                  * leftover join state. */
 792                 BUG_ON(dlm->joining_node != assert->node_idx);
 793                 set_bit(assert->node_idx, dlm->domain_map);
 794                 __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
 795
 796                 printk(KERN_INFO "ocfs2_dlm: Node %u joins domain %s\n",
 797                        assert->node_idx, dlm->name);
 798                 __dlm_print_nodes(dlm);
 799
 800                 /* notify anything attached to the heartbeat events */
 801                 dlm_hb_event_notify_attached(dlm, assert->node_idx, 1);
 802
 803                 spin_unlock(&dlm->spinlock);
 804         }
 805         spin_unlock(&dlm_domain_lock);
 806
 807         return 0;
 808 }
 809
 810 static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data,
 811                                    void **ret_data)
 812 {
 813         struct dlm_cancel_join *cancel;
 814         struct dlm_ctxt *dlm = NULL;
 815
 816         cancel = (struct dlm_cancel_join *) msg->buf;
 817
 818         mlog(0, "node %u cancels join on domain %s\n", cancel->node_idx,
 819                   cancel->domain);
 820
 821         spin_lock(&dlm_domain_lock);
 822         dlm = __dlm_lookup_domain_full(cancel->domain, cancel->name_len);
 823
 824         if (dlm) {
 825                 spin_lock(&dlm->spinlock);
 826
 827                 /* Yikes, this guy wants to cancel his join. No
 828                  * problem, we simply cleanup our join state. */
 829                 BUG_ON(dlm->joining_node != cancel->node_idx);
 830                 __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
 831
 832                 spin_unlock(&dlm->spinlock);
 833         }
 834         spin_unlock(&dlm_domain_lock);
 835
 836         return 0;
 837 }
 838
 839 static int dlm_send_one_join_cancel(struct dlm_ctxt *dlm,
 840                                     unsigned int node)
 841 {
 842         int status;
 843         struct dlm_cancel_join cancel_msg;
 844
 845         memset(&cancel_msg, 0, sizeof(cancel_msg));
 846         cancel_msg.node_idx = dlm->node_num;
 847         cancel_msg.name_len = strlen(dlm->name);
 848         memcpy(cancel_msg.domain, dlm->name, cancel_msg.name_len);
 849
 850         status = o2net_send_message(DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
 851                                     &cancel_msg, sizeof(cancel_msg), node,
 852                                     NULL);
 853         if (status < 0) {
 854                 mlog_errno(status);
 855                 goto bail;
 856         }
 857
 858 bail:
 859         return status;
 860 }
 861
 862 /* map_size should be in bytes. */
 863 static int dlm_send_join_cancels(struct dlm_ctxt *dlm,
 864                                  unsigned long *node_map,
 865                                  unsigned int map_size)
 866 {
 867         int status, tmpstat;
 868         unsigned int node;
 869
 870         if (map_size != (BITS_TO_LONGS(O2NM_MAX_NODES) *
 871                          sizeof(unsigned long))) {
 872                 mlog(ML_ERROR,
 873                      "map_size %u != BITS_TO_LONGS(O2NM_MAX_NODES) %u\n",
 874                      map_size, BITS_TO_LONGS(O2NM_MAX_NODES));
 875                 return -EINVAL;
 876         }
 877
 878         status = 0;
 879         node = -1;
 880         while ((node = find_next_bit(node_map, O2NM_MAX_NODES,
 881                                      node + 1)) < O2NM_MAX_NODES) {
 882                 if (node == dlm->node_num)
 883                         continue;
 884
 885                 tmpstat = dlm_send_one_join_cancel(dlm, node);
 886                 if (tmpstat) {
 887                         mlog(ML_ERROR, "Error return %d cancelling join on "
 888                              "node %d\n", tmpstat, node);
 889                         if (!status)
 890                                 status = tmpstat;
 891                 }
 892         }
 893
 894         if (status)
 895                 mlog_errno(status);
 896         return status;
 897 }
 898
 899 static int dlm_request_join(struct dlm_ctxt *dlm,
 900                             int node,
 901                             enum dlm_query_join_response *response)
 902 {
 903         int status, retval;
 904         struct dlm_query_join_request join_msg;
 905
 906         mlog(0, "querying node %d\n", node);
 907
 908         memset(&join_msg, 0, sizeof(join_msg));
 909         join_msg.node_idx = dlm->node_num;
 910         join_msg.name_len = strlen(dlm->name);
 911         memcpy(join_msg.domain, dlm->name, join_msg.name_len);
 912
 913         /* copy live node map to join message */
 914         byte_copymap(join_msg.node_map, dlm->live_nodes_map, O2NM_MAX_NODES);
 915
 916         status = o2net_send_message(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY, &join_msg,
 917                                     sizeof(join_msg), node, &retval);
 918         if (status < 0 && status != -ENOPROTOOPT) {
 919                 mlog_errno(status);
 920                 goto bail;
 921         }
 922
 923         /* -ENOPROTOOPT from the net code means the other side isn't
 924             listening for our message type -- that's fine, it means
 925             his dlm isn't up, so we can consider him a 'yes' but not
 926             joined into the domain.  */
 927         if (status == -ENOPROTOOPT) {
 928                 status = 0;
 929                 *response = JOIN_OK_NO_MAP;
 930         } else if (retval == JOIN_DISALLOW ||
 931                    retval == JOIN_OK ||
 932                    retval == JOIN_OK_NO_MAP) {
 933                 *response = retval;
 934         } else {
 935                 status = -EINVAL;
 936                 mlog(ML_ERROR, "invalid response %d from node %u\n", retval,
 937                      node);
 938         }
 939
 940         mlog(0, "status %d, node %d response is %d\n", status, node,
 941                   *response);
 942
 943 bail:
 944         return status;
 945 }
 946
 947 static int dlm_send_one_join_assert(struct dlm_ctxt *dlm,
 948                                     unsigned int node)
 949 {
 950         int status;
 951         struct dlm_assert_joined assert_msg;
 952
 953         mlog(0, "Sending join assert to node %u\n", node);
 954
 955         memset(&assert_msg, 0, sizeof(assert_msg));
 956         assert_msg.node_idx = dlm->node_num;
 957         assert_msg.name_len = strlen(dlm->name);
 958         memcpy(assert_msg.domain, dlm->name, assert_msg.name_len);
 959
 960         status = o2net_send_message(DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
 961                                     &assert_msg, sizeof(assert_msg), node,
 962                                     NULL);
 963         if (status < 0)
 964                 mlog_errno(status);
 965
 966         return status;
 967 }
 968
 969 static void dlm_send_join_asserts(struct dlm_ctxt *dlm,
 970                                   unsigned long *node_map)
 971 {
 972         int status, node, live;
 973
 974         status = 0;
 975         node = -1;
 976         while ((node = find_next_bit(node_map, O2NM_MAX_NODES,
 977                                      node + 1)) < O2NM_MAX_NODES) {
 978                 if (node == dlm->node_num)
 979                         continue;
 980
 981                 do {
 982                         /* It is very important that this message be
 983                          * received so we spin until either the node
 984                          * has died or it gets the message. */
 985                         status = dlm_send_one_join_assert(dlm, node);
 986
 987                         spin_lock(&dlm->spinlock);
 988                         live = test_bit(node, dlm->live_nodes_map);
 989                         spin_unlock(&dlm->spinlock);
 990
 991                         if (status) {
 992                                 mlog(ML_ERROR, "Error return %d asserting "
 993                                      "join on node %d\n", status, node);
 994
 995                                 /* give us some time between errors... */
 996                                 if (live)
 997                                         msleep(DLM_DOMAIN_BACKOFF_MS);
 998                         }
 999                 } while (status && live);
1000         }
1001 }
1002
1003 struct domain_join_ctxt {
1004         unsigned long live_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1005         unsigned long yes_resp_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1006 };
1007
1008 static int dlm_should_restart_join(struct dlm_ctxt *dlm,
1009                                    struct domain_join_ctxt *ctxt,
1010                                    enum dlm_query_join_response response)
1011 {
1012         int ret;
1013
1014         if (response == JOIN_DISALLOW) {
1015                 mlog(0, "Latest response of disallow -- should restart\n");
1016                 return 1;
1017         }
1018
1019         spin_lock(&dlm->spinlock);
1020         /* For now, we restart the process if the node maps have
1021          * changed at all */
1022         ret = memcmp(ctxt->live_map, dlm->live_nodes_map,
1023                      sizeof(dlm->live_nodes_map));
1024         spin_unlock(&dlm->spinlock);
1025
1026         if (ret)
1027                 mlog(0, "Node maps changed -- should restart\n");
1028
1029         return ret;
1030 }
1031
1032 static int dlm_try_to_join_domain(struct dlm_ctxt *dlm)
1033 {
1034         int status = 0, tmpstat, node;
1035         struct domain_join_ctxt *ctxt;
1036         enum dlm_query_join_response response;
1037
1038         mlog_entry("%p", dlm);
1039
1040         ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL);
1041         if (!ctxt) {
1042                 status = -ENOMEM;
1043                 mlog_errno(status);
1044                 goto bail;
1045         }
1046
1047         /* group sem locking should work for us here -- we're already
1048          * registered for heartbeat events so filling this should be
1049          * atomic wrt getting those handlers called. */
1050         o2hb_fill_node_map(dlm->live_nodes_map, sizeof(dlm->live_nodes_map));
1051
1052         spin_lock(&dlm->spinlock);
1053         memcpy(ctxt->live_map, dlm->live_nodes_map, sizeof(ctxt->live_map));
1054
1055         __dlm_set_joining_node(dlm, dlm->node_num);
1056
1057         spin_unlock(&dlm->spinlock);
1058
1059         node = -1;
1060         while ((node = find_next_bit(ctxt->live_map, O2NM_MAX_NODES,
1061                                      node + 1)) < O2NM_MAX_NODES) {
1062                 if (node == dlm->node_num)
1063                         continue;
1064
1065                 status = dlm_request_join(dlm, node, &response);
1066                 if (status < 0) {
1067                         mlog_errno(status);
1068                         goto bail;
1069                 }
1070
1071                 /* Ok, either we got a response or the node doesn't have a
1072                  * dlm up. */
1073                 if (response == JOIN_OK)
1074                         set_bit(node, ctxt->yes_resp_map);
1075
1076                 if (dlm_should_restart_join(dlm, ctxt, response)) {
1077                         status = -EAGAIN;
1078                         goto bail;
1079                 }
1080         }
1081
1082         mlog(0, "Yay, done querying nodes!\n");
1083
1084         /* Yay, everyone agree's we can join the domain. My domain is
1085          * comprised of all nodes who were put in the
1086          * yes_resp_map. Copy that into our domain map and send a join
1087          * assert message to clean up everyone elses state. */
1088         spin_lock(&dlm->spinlock);
1089         memcpy(dlm->domain_map, ctxt->yes_resp_map,
1090                sizeof(ctxt->yes_resp_map));
1091         set_bit(dlm->node_num, dlm->domain_map);
1092         spin_unlock(&dlm->spinlock);
1093
1094         dlm_send_join_asserts(dlm, ctxt->yes_resp_map);
1095
1096         /* Joined state *must* be set before the joining node
1097          * information, otherwise the query_join handler may read no
1098          * current joiner but a state of NEW and tell joining nodes
1099          * we're not in the domain. */
1100         spin_lock(&dlm_domain_lock);
1101         dlm->dlm_state = DLM_CTXT_JOINED;
1102         dlm->num_joins++;
1103         spin_unlock(&dlm_domain_lock);
1104
1105 bail:
1106         spin_lock(&dlm->spinlock);
1107         __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
1108         if (!status)
1109                 __dlm_print_nodes(dlm);
1110         spin_unlock(&dlm->spinlock);
1111
1112         if (ctxt) {
1113                 /* Do we need to send a cancel message to any nodes? */
1114                 if (status < 0) {
1115                         tmpstat = dlm_send_join_cancels(dlm,
1116                                                         ctxt->yes_resp_map,
1117                                                         sizeof(ctxt->yes_resp_map));
1118                         if (tmpstat < 0)
1119                                 mlog_errno(tmpstat);
1120                 }
1121                 kfree(ctxt);
1122         }
1123
1124         mlog(0, "returning %d\n", status);
1125         return status;
1126 }
1127
1128 static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm)
1129 {
1130         o2hb_unregister_callback(&dlm->dlm_hb_up);
1131         o2hb_unregister_callback(&dlm->dlm_hb_down);
1132         o2net_unregister_handler_list(&dlm->dlm_domain_handlers);
1133 }
1134
1135 static int dlm_register_domain_handlers(struct dlm_ctxt *dlm)
1136 {
1137         int status;
1138
1139         mlog(0, "registering handlers.\n");
1140
1141         o2hb_setup_callback(&dlm->dlm_hb_down, O2HB_NODE_DOWN_CB,
1142                             dlm_hb_node_down_cb, dlm, DLM_HB_NODE_DOWN_PRI);
1143         status = o2hb_register_callback(&dlm->dlm_hb_down);
1144         if (status)
1145                 goto bail;
1146
1147         o2hb_setup_callback(&dlm->dlm_hb_up, O2HB_NODE_UP_CB,
1148                             dlm_hb_node_up_cb, dlm, DLM_HB_NODE_UP_PRI);
1149         status = o2hb_register_callback(&dlm->dlm_hb_up);
1150         if (status)
1151                 goto bail;
1152
1153         status = o2net_register_handler(DLM_MASTER_REQUEST_MSG, dlm->key,
1154                                         sizeof(struct dlm_master_request),
1155                                         dlm_master_request_handler,
1156                                         dlm, NULL, &dlm->dlm_domain_handlers);
1157         if (status)
1158                 goto bail;
1159
1160         status = o2net_register_handler(DLM_ASSERT_MASTER_MSG, dlm->key,
1161                                         sizeof(struct dlm_assert_master),
1162                                         dlm_assert_master_handler,
1163                                         dlm, dlm_assert_master_post_handler,
1164                                         &dlm->dlm_domain_handlers);
1165         if (status)
1166                 goto bail;
1167
1168         status = o2net_register_handler(DLM_CREATE_LOCK_MSG, dlm->key,
1169                                         sizeof(struct dlm_create_lock),
1170                                         dlm_create_lock_handler,
1171                                         dlm, NULL, &dlm->dlm_domain_handlers);
1172         if (status)
1173                 goto bail;
1174
1175         status = o2net_register_handler(DLM_CONVERT_LOCK_MSG, dlm->key,
1176                                         DLM_CONVERT_LOCK_MAX_LEN,
1177                                         dlm_convert_lock_handler,
1178                                         dlm, NULL, &dlm->dlm_domain_handlers);
1179         if (status)
1180                 goto bail;
1181
1182         status = o2net_register_handler(DLM_UNLOCK_LOCK_MSG, dlm->key,
1183                                         DLM_UNLOCK_LOCK_MAX_LEN,
1184                                         dlm_unlock_lock_handler,
1185                                         dlm, NULL, &dlm->dlm_domain_handlers);
1186         if (status)
1187                 goto bail;
1188
1189         status = o2net_register_handler(DLM_PROXY_AST_MSG, dlm->key,
1190                                         DLM_PROXY_AST_MAX_LEN,
1191                                         dlm_proxy_ast_handler,
1192                                         dlm, NULL, &dlm->dlm_domain_handlers);
1193         if (status)
1194                 goto bail;
1195
1196         status = o2net_register_handler(DLM_EXIT_DOMAIN_MSG, dlm->key,
1197                                         sizeof(struct dlm_exit_domain),
1198                                         dlm_exit_domain_handler,
1199                                         dlm, NULL, &dlm->dlm_domain_handlers);
1200         if (status)
1201                 goto bail;
1202
1203         status = o2net_register_handler(DLM_DEREF_LOCKRES_MSG, dlm->key,
1204                                         sizeof(struct dlm_deref_lockres),
1205                                         dlm_deref_lockres_handler,
1206                                         dlm, NULL, &dlm->dlm_domain_handlers);
1207         if (status)
1208                 goto bail;
1209
1210         status = o2net_register_handler(DLM_MIGRATE_REQUEST_MSG, dlm->key,
1211                                         sizeof(struct dlm_migrate_request),
1212                                         dlm_migrate_request_handler,
1213                                         dlm, NULL, &dlm->dlm_domain_handlers);
1214         if (status)
1215                 goto bail;
1216
1217         status = o2net_register_handler(DLM_MIG_LOCKRES_MSG, dlm->key,
1218                                         DLM_MIG_LOCKRES_MAX_LEN,
1219                                         dlm_mig_lockres_handler,
1220                                         dlm, NULL, &dlm->dlm_domain_handlers);
1221         if (status)
1222                 goto bail;
1223
1224         status = o2net_register_handler(DLM_MASTER_REQUERY_MSG, dlm->key,
1225                                         sizeof(struct dlm_master_requery),
1226                                         dlm_master_requery_handler,
1227                                         dlm, NULL, &dlm->dlm_domain_handlers);
1228         if (status)
1229                 goto bail;
1230
1231         status = o2net_register_handler(DLM_LOCK_REQUEST_MSG, dlm->key,
1232                                         sizeof(struct dlm_lock_request),
1233                                         dlm_request_all_locks_handler,
1234                                         dlm, NULL, &dlm->dlm_domain_handlers);
1235         if (status)
1236                 goto bail;
1237
1238         status = o2net_register_handler(DLM_RECO_DATA_DONE_MSG, dlm->key,
1239                                         sizeof(struct dlm_reco_data_done),
1240                                         dlm_reco_data_done_handler,
1241                                         dlm, NULL, &dlm->dlm_domain_handlers);
1242         if (status)
1243                 goto bail;
1244
1245         status = o2net_register_handler(DLM_BEGIN_RECO_MSG, dlm->key,
1246                                         sizeof(struct dlm_begin_reco),
1247                                         dlm_begin_reco_handler,
1248                                         dlm, NULL, &dlm->dlm_domain_handlers);
1249         if (status)
1250                 goto bail;
1251
1252         status = o2net_register_handler(DLM_FINALIZE_RECO_MSG, dlm->key,
1253                                         sizeof(struct dlm_finalize_reco),
1254                                         dlm_finalize_reco_handler,
1255                                         dlm, NULL, &dlm->dlm_domain_handlers);
1256         if (status)
1257                 goto bail;
1258
1259 bail:
1260         if (status)
1261                 dlm_unregister_domain_handlers(dlm);
1262
1263         return status;
1264 }
1265
1266 static int dlm_join_domain(struct dlm_ctxt *dlm)
1267 {
1268         int status;
1269         unsigned int backoff;
1270         unsigned int total_backoff = 0;
1271
1272         BUG_ON(!dlm);
1273
1274         mlog(0, "Join domain %s\n", dlm->name);
1275
1276         status = dlm_register_domain_handlers(dlm);
1277         if (status) {
1278                 mlog_errno(status);
1279                 goto bail;
1280         }
1281
1282         status = dlm_launch_thread(dlm);
1283         if (status < 0) {
1284                 mlog_errno(status);
1285                 goto bail;
1286         }
1287
1288         status = dlm_launch_recovery_thread(dlm);
1289         if (status < 0) {
1290                 mlog_errno(status);
1291                 goto bail;
1292         }
1293
1294         dlm->dlm_worker = create_singlethread_workqueue("dlm_wq");
1295         if (!dlm->dlm_worker) {
1296                 status = -ENOMEM;
1297                 mlog_errno(status);
1298                 goto bail;
1299         }
1300
1301         do {
1302                 status = dlm_try_to_join_domain(dlm);
1303
1304                 /* If we're racing another node to the join, then we
1305                  * need to back off temporarily and let them
1306                  * complete. */
1307 #define DLM_JOIN_TIMEOUT_MSECS  90000
1308                 if (status == -EAGAIN) {
1309                         if (signal_pending(current)) {
1310                                 status = -ERESTARTSYS;
1311                                 goto bail;
1312                         }
1313
1314                         if (total_backoff >
1315                             msecs_to_jiffies(DLM_JOIN_TIMEOUT_MSECS)) {
1316                                 status = -ERESTARTSYS;
1317                                 mlog(ML_NOTICE, "Timed out joining dlm domain "
1318                                      "%s after %u msecs\n", dlm->name,
1319                                      jiffies_to_msecs(total_backoff));
1320                                 goto bail;
1321                         }
1322
1323                         /*
1324                          * <chip> After you!
1325                          * <dale> No, after you!
1326                          * <chip> I insist!
1327                          * <dale> But you first!
1328                          * ...
1329                          */
1330                         backoff = (unsigned int)(jiffies & 0x3);
1331                         backoff *= DLM_DOMAIN_BACKOFF_MS;
1332                         total_backoff += backoff;
1333                         mlog(0, "backoff %d\n", backoff);
1334                         msleep(backoff);
1335                 }
1336         } while (status == -EAGAIN);
1337
1338         if (status < 0) {
1339                 mlog_errno(status);
1340                 goto bail;
1341         }
1342
1343         status = 0;
1344 bail:
1345         wake_up(&dlm_domain_events);
1346
1347         if (status) {
1348                 dlm_unregister_domain_handlers(dlm);
1349                 dlm_complete_thread(dlm);
1350                 dlm_complete_recovery_thread(dlm);
1351                 dlm_destroy_dlm_worker(dlm);
1352         }
1353
1354         return status;
1355 }
1356
1357 static struct dlm_ctxt *dlm_alloc_ctxt(const char *domain,
1358                                 u32 key)
1359 {
1360         int i;
1361         struct dlm_ctxt *dlm = NULL;
1362
1363         dlm = kzalloc(sizeof(*dlm), GFP_KERNEL);
1364         if (!dlm) {
1365                 mlog_errno(-ENOMEM);
1366                 goto leave;
1367         }
1368
1369         dlm->name = kmalloc(strlen(domain) + 1, GFP_KERNEL);
1370         if (dlm->name == NULL) {
1371                 mlog_errno(-ENOMEM);
1372                 kfree(dlm);
1373                 dlm = NULL;
1374                 goto leave;
1375         }
1376
1377         dlm->lockres_hash = (struct hlist_head **)dlm_alloc_pagevec(DLM_HASH_PAGES);
1378         if (!dlm->lockres_hash) {
1379                 mlog_errno(-ENOMEM);
1380                 kfree(dlm->name);
1381                 kfree(dlm);
1382                 dlm = NULL;
1383                 goto leave;
1384         }
1385
1386         for (i = 0; i < DLM_HASH_BUCKETS; i++)
1387                 INIT_HLIST_HEAD(dlm_lockres_hash(dlm, i));
1388
1389         strcpy(dlm->name, domain);
1390         dlm->key = key;
1391         dlm->node_num = o2nm_this_node();
1392
1393         spin_lock_init(&dlm->spinlock);
1394         spin_lock_init(&dlm->master_lock);
1395         spin_lock_init(&dlm->ast_lock);
1396         INIT_LIST_HEAD(&dlm->list);
1397         INIT_LIST_HEAD(&dlm->dirty_list);
1398         INIT_LIST_HEAD(&dlm->reco.resources);
1399         INIT_LIST_HEAD(&dlm->reco.received);
1400         INIT_LIST_HEAD(&dlm->reco.node_data);
1401         INIT_LIST_HEAD(&dlm->purge_list);
1402         INIT_LIST_HEAD(&dlm->dlm_domain_handlers);
1403         dlm->reco.state = 0;
1404
1405         INIT_LIST_HEAD(&dlm->pending_asts);
1406         INIT_LIST_HEAD(&dlm->pending_basts);
1407
1408         mlog(0, "dlm->recovery_map=%p, &(dlm->recovery_map[0])=%p\n",
1409                   dlm->recovery_map, &(dlm->recovery_map[0]));
1410
1411         memset(dlm->recovery_map, 0, sizeof(dlm->recovery_map));
1412         memset(dlm->live_nodes_map, 0, sizeof(dlm->live_nodes_map));
1413         memset(dlm->domain_map, 0, sizeof(dlm->domain_map));
1414
1415         dlm->dlm_thread_task = NULL;
1416         dlm->dlm_reco_thread_task = NULL;
1417         dlm->dlm_worker = NULL;
1418         init_waitqueue_head(&dlm->dlm_thread_wq);
1419         init_waitqueue_head(&dlm->dlm_reco_thread_wq);
1420         init_waitqueue_head(&dlm->reco.event);
1421         init_waitqueue_head(&dlm->ast_wq);
1422         init_waitqueue_head(&dlm->migration_wq);
1423         INIT_LIST_HEAD(&dlm->master_list);
1424         INIT_LIST_HEAD(&dlm->mle_hb_events);
1425
1426         dlm->joining_node = DLM_LOCK_RES_OWNER_UNKNOWN;
1427         init_waitqueue_head(&dlm->dlm_join_events);
1428
1429         dlm->reco.new_master = O2NM_INVALID_NODE_NUM;
1430         dlm->reco.dead_node = O2NM_INVALID_NODE_NUM;
1431         atomic_set(&dlm->local_resources, 0);
1432         atomic_set(&dlm->remote_resources, 0);
1433         atomic_set(&dlm->unknown_resources, 0);
1434
1435         spin_lock_init(&dlm->work_lock);
1436         INIT_LIST_HEAD(&dlm->work_list);
1437         INIT_WORK(&dlm->dispatched_work, dlm_dispatch_work);
1438
1439         kref_init(&dlm->dlm_refs);
1440         dlm->dlm_state = DLM_CTXT_NEW;
1441
1442         INIT_LIST_HEAD(&dlm->dlm_eviction_callbacks);
1443
1444         mlog(0, "context init: refcount %u\n",
1445                   atomic_read(&dlm->dlm_refs.refcount));
1446
1447 leave:
1448         return dlm;
1449 }
1450
1451 /*
1452  * dlm_register_domain: one-time setup per "domain"
1453  */
1454 struct dlm_ctxt * dlm_register_domain(const char *domain,
1455                                u32 key)
1456 {
1457         int ret;
1458         struct dlm_ctxt *dlm = NULL;
1459         struct dlm_ctxt *new_ctxt = NULL;
1460
1461         if (strlen(domain) > O2NM_MAX_NAME_LEN) {
1462                 ret = -ENAMETOOLONG;
1463                 mlog(ML_ERROR, "domain name length too long\n");
1464                 goto leave;
1465         }
1466
1467         if (!o2hb_check_local_node_heartbeating()) {
1468                 mlog(ML_ERROR, "the local node has not been configured, or is "
1469                      "not heartbeating\n");
1470                 ret = -EPROTO;
1471                 goto leave;
1472         }
1473
1474         mlog(0, "register called for domain \"%s\"\n", domain);
1475
1476 retry:
1477         dlm = NULL;
1478         if (signal_pending(current)) {
1479                 ret = -ERESTARTSYS;
1480                 mlog_errno(ret);
1481                 goto leave;
1482         }
1483
1484         spin_lock(&dlm_domain_lock);
1485
1486         dlm = __dlm_lookup_domain(domain);
1487         if (dlm) {
1488                 if (dlm->dlm_state != DLM_CTXT_JOINED) {
1489                         spin_unlock(&dlm_domain_lock);
1490
1491                         mlog(0, "This ctxt is not joined yet!\n");
1492                         wait_event_interruptible(dlm_domain_events,
1493                                                  dlm_wait_on_domain_helper(
1494                                                          domain));
1495                         goto retry;
1496                 }
1497
1498                 __dlm_get(dlm);
1499                 dlm->num_joins++;
1500
1501                 spin_unlock(&dlm_domain_lock);
1502
1503                 ret = 0;
1504                 goto leave;
1505         }
1506
1507         /* doesn't exist */
1508         if (!new_ctxt) {
1509                 spin_unlock(&dlm_domain_lock);
1510
1511                 new_ctxt = dlm_alloc_ctxt(domain, key);
1512                 if (new_ctxt)
1513                         goto retry;
1514
1515                 ret = -ENOMEM;
1516                 mlog_errno(ret);
1517                 goto leave;
1518         }
1519
1520         /* a little variable switch-a-roo here... */
1521         dlm = new_ctxt;
1522         new_ctxt = NULL;
1523
1524         /* add the new domain */
1525         list_add_tail(&dlm->list, &dlm_domains);
1526         spin_unlock(&dlm_domain_lock);
1527
1528         ret = dlm_join_domain(dlm);
1529         if (ret) {
1530                 mlog_errno(ret);
1531                 dlm_put(dlm);
1532                 goto leave;
1533         }
1534
1535         ret = 0;
1536 leave:
1537         if (new_ctxt)
1538                 dlm_free_ctxt_mem(new_ctxt);
1539
1540         if (ret < 0)
1541                 dlm = ERR_PTR(ret);
1542
1543         return dlm;
1544 }
1545 EXPORT_SYMBOL_GPL(dlm_register_domain);
1546
1547 static LIST_HEAD(dlm_join_handlers);
1548
1549 static void dlm_unregister_net_handlers(void)
1550 {
1551         o2net_unregister_handler_list(&dlm_join_handlers);
1552 }
1553
1554 static int dlm_register_net_handlers(void)
1555 {
1556         int status = 0;
1557
1558         status = o2net_register_handler(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY,
1559                                         sizeof(struct dlm_query_join_request),
1560                                         dlm_query_join_handler,
1561                                         NULL, NULL, &dlm_join_handlers);
1562         if (status)
1563                 goto bail;
1564
1565         status = o2net_register_handler(DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
1566                                         sizeof(struct dlm_assert_joined),
1567                                         dlm_assert_joined_handler,
1568                                         NULL, NULL, &dlm_join_handlers);
1569         if (status)
1570                 goto bail;
1571
1572         status = o2net_register_handler(DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
1573                                         sizeof(struct dlm_cancel_join),
1574                                         dlm_cancel_join_handler,
1575                                         NULL, NULL, &dlm_join_handlers);
1576
1577 bail:
1578         if (status < 0)
1579                 dlm_unregister_net_handlers();
1580
1581         return status;
1582 }
1583
1584 /* Domain eviction callback handling.
1585  *
1586  * The file system requires notification of node death *before* the
1587  * dlm completes it's recovery work, otherwise it may be able to
1588  * acquire locks on resources requiring recovery. Since the dlm can
1589  * evict a node from it's domain *before* heartbeat fires, a similar
1590  * mechanism is required. */
1591
1592 /* Eviction is not expected to happen often, so a per-domain lock is
1593  * not necessary. Eviction callbacks are allowed to sleep for short
1594  * periods of time. */
1595 static DECLARE_RWSEM(dlm_callback_sem);
1596
1597 void dlm_fire_domain_eviction_callbacks(struct dlm_ctxt *dlm,
1598                                         int node_num)
1599 {
1600         struct list_head *iter;
1601         struct dlm_eviction_cb *cb;
1602
1603         down_read(&dlm_callback_sem);
1604         list_for_each(iter, &dlm->dlm_eviction_callbacks) {
1605                 cb = list_entry(iter, struct dlm_eviction_cb, ec_item);
1606
1607                 cb->ec_func(node_num, cb->ec_data);
1608         }
1609         up_read(&dlm_callback_sem);
1610 }
1611
1612 void dlm_setup_eviction_cb(struct dlm_eviction_cb *cb,
1613                            dlm_eviction_func *f,
1614                            void *data)
1615 {
1616         INIT_LIST_HEAD(&cb->ec_item);
1617         cb->ec_func = f;
1618         cb->ec_data = data;
1619 }
1620 EXPORT_SYMBOL_GPL(dlm_setup_eviction_cb);
1621
1622 void dlm_register_eviction_cb(struct dlm_ctxt *dlm,
1623                               struct dlm_eviction_cb *cb)
1624 {
1625         down_write(&dlm_callback_sem);
1626         list_add_tail(&cb->ec_item, &dlm->dlm_eviction_callbacks);
1627         up_write(&dlm_callback_sem);
1628 }
1629 EXPORT_SYMBOL_GPL(dlm_register_eviction_cb);
1630
1631 void dlm_unregister_eviction_cb(struct dlm_eviction_cb *cb)
1632 {
1633         down_write(&dlm_callback_sem);
1634         list_del_init(&cb->ec_item);
1635         up_write(&dlm_callback_sem);
1636 }
1637 EXPORT_SYMBOL_GPL(dlm_unregister_eviction_cb);
1638
1639 static int __init dlm_init(void)
1640 {
1641         int status;
1642
1643         dlm_print_version();
1644
1645         status = dlm_init_mle_cache();
1646         if (status)
1647                 return -1;
1648
1649         status = dlm_register_net_handlers();
1650         if (status) {
1651                 dlm_destroy_mle_cache();
1652                 return -1;
1653         }
1654
1655         return 0;
1656 }
1657
1658 static void __exit dlm_exit (void)
1659 {
1660         dlm_unregister_net_handlers();
1661         dlm_destroy_mle_cache();
1662 }
1663
1664 MODULE_AUTHOR("Oracle");
1665 MODULE_LICENSE("GPL");
1666
1667 module_init(dlm_init);
1668 module_exit(dlm_exit);