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                         /* Give dlm_thread time to purge the lockres' */
 661                         msleep(500);
 662                         mlog(0, "%s: more migration to do\n", dlm->name);
 663                 }
 664                 dlm_mark_domain_leaving(dlm);
 665                 dlm_leave_domain(dlm);
 666                 dlm_complete_dlm_shutdown(dlm);
 667         }
 668         dlm_put(dlm);
 669 }
 670 EXPORT_SYMBOL_GPL(dlm_unregister_domain);
 671
 672 static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
 673                                   void **ret_data)
 674 {
 675         struct dlm_query_join_request *query;
 676         enum dlm_query_join_response response;
 677         struct dlm_ctxt *dlm = NULL;
 678         u8 nodenum;
 679
 680         query = (struct dlm_query_join_request *) msg->buf;
 681
 682         mlog(0, "node %u wants to join domain %s\n", query->node_idx,
 683                   query->domain);
 684
 685         /*
 686          * If heartbeat doesn't consider the node live, tell it
 687          * to back off and try again.  This gives heartbeat a chance
 688          * to catch up.
 689          */
 690         if (!o2hb_check_node_heartbeating(query->node_idx)) {
 691                 mlog(0, "node %u is not in our live map yet\n",
 692                      query->node_idx);
 693
 694                 response = JOIN_DISALLOW;
 695                 goto respond;
 696         }
 697
 698         response = JOIN_OK_NO_MAP;
 699
 700         spin_lock(&dlm_domain_lock);
 701         dlm = __dlm_lookup_domain_full(query->domain, query->name_len);
 702         if (!dlm)
 703                 goto unlock_respond;
 704
 705         /*
 706          * There is a small window where the joining node may not see the
 707          * node(s) that just left but still part of the cluster. DISALLOW
 708          * join request if joining node has different node map.
 709          */
 710         nodenum=0;
 711         while (nodenum < O2NM_MAX_NODES) {
 712                 if (test_bit(nodenum, dlm->domain_map)) {
 713                         if (!byte_test_bit(nodenum, query->node_map)) {
 714                                 mlog(0, "disallow join as node %u does not "
 715                                      "have node %u in its nodemap\n",
 716                                      query->node_idx, nodenum);
 717                                 response = JOIN_DISALLOW;
 718                                 goto unlock_respond;
 719                         }
 720                 }
 721                 nodenum++;
 722         }
 723
 724         /* Once the dlm ctxt is marked as leaving then we don't want
 725          * to be put in someone's domain map.
 726          * Also, explicitly disallow joining at certain troublesome
 727          * times (ie. during recovery). */
 728         if (dlm && dlm->dlm_state != DLM_CTXT_LEAVING) {
 729                 int bit = query->node_idx;
 730                 spin_lock(&dlm->spinlock);
 731
 732                 if (dlm->dlm_state == DLM_CTXT_NEW &&
 733                     dlm->joining_node == DLM_LOCK_RES_OWNER_UNKNOWN) {
 734                         /*If this is a brand new context and we
 735                          * haven't started our join process yet, then
 736                          * the other node won the race. */
 737                         response = JOIN_OK_NO_MAP;
 738                 } else if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
 739                         /* Disallow parallel joins. */
 740                         response = JOIN_DISALLOW;
 741                 } else if (dlm->reco.state & DLM_RECO_STATE_ACTIVE) {
 742                         mlog(0, "node %u trying to join, but recovery "
 743                              "is ongoing.\n", bit);
 744                         response = JOIN_DISALLOW;
 745                 } else if (test_bit(bit, dlm->recovery_map)) {
 746                         mlog(0, "node %u trying to join, but it "
 747                              "still needs recovery.\n", bit);
 748                         response = JOIN_DISALLOW;
 749                 } else if (test_bit(bit, dlm->domain_map)) {
 750                         mlog(0, "node %u trying to join, but it "
 751                              "is still in the domain! needs recovery?\n",
 752                              bit);
 753                         response = JOIN_DISALLOW;
 754                 } else {
 755                         /* Alright we're fully a part of this domain
 756                          * so we keep some state as to who's joining
 757                          * and indicate to him that needs to be fixed
 758                          * up. */
 759                         response = JOIN_OK;
 760                         __dlm_set_joining_node(dlm, query->node_idx);
 761                 }
 762
 763                 spin_unlock(&dlm->spinlock);
 764         }
 765 unlock_respond:
 766         spin_unlock(&dlm_domain_lock);
 767
 768 respond:
 769         mlog(0, "We respond with %u\n", response);
 770
 771         return response;
 772 }
 773
 774 static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data,
 775                                      void **ret_data)
 776 {
 777         struct dlm_assert_joined *assert;
 778         struct dlm_ctxt *dlm = NULL;
 779
 780         assert = (struct dlm_assert_joined *) msg->buf;
 781
 782         mlog(0, "node %u asserts join on domain %s\n", assert->node_idx,
 783                   assert->domain);
 784
 785         spin_lock(&dlm_domain_lock);
 786         dlm = __dlm_lookup_domain_full(assert->domain, assert->name_len);
 787         /* XXX should we consider no dlm ctxt an error? */
 788         if (dlm) {
 789                 spin_lock(&dlm->spinlock);
 790
 791                 /* Alright, this node has officially joined our
 792                  * domain. Set him in the map and clean up our
 793                  * leftover join state. */
 794                 BUG_ON(dlm->joining_node != assert->node_idx);
 795                 set_bit(assert->node_idx, dlm->domain_map);
 796                 __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
 797
 798                 printk(KERN_INFO "ocfs2_dlm: Node %u joins domain %s\n",
 799                        assert->node_idx, dlm->name);
 800                 __dlm_print_nodes(dlm);
 801
 802                 /* notify anything attached to the heartbeat events */
 803                 dlm_hb_event_notify_attached(dlm, assert->node_idx, 1);
 804
 805                 spin_unlock(&dlm->spinlock);
 806         }
 807         spin_unlock(&dlm_domain_lock);
 808
 809         return 0;
 810 }
 811
 812 static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data,
 813                                    void **ret_data)
 814 {
 815         struct dlm_cancel_join *cancel;
 816         struct dlm_ctxt *dlm = NULL;
 817
 818         cancel = (struct dlm_cancel_join *) msg->buf;
 819
 820         mlog(0, "node %u cancels join on domain %s\n", cancel->node_idx,
 821                   cancel->domain);
 822
 823         spin_lock(&dlm_domain_lock);
 824         dlm = __dlm_lookup_domain_full(cancel->domain, cancel->name_len);
 825
 826         if (dlm) {
 827                 spin_lock(&dlm->spinlock);
 828
 829                 /* Yikes, this guy wants to cancel his join. No
 830                  * problem, we simply cleanup our join state. */
 831                 BUG_ON(dlm->joining_node != cancel->node_idx);
 832                 __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
 833
 834                 spin_unlock(&dlm->spinlock);
 835         }
 836         spin_unlock(&dlm_domain_lock);
 837
 838         return 0;
 839 }
 840
 841 static int dlm_send_one_join_cancel(struct dlm_ctxt *dlm,
 842                                     unsigned int node)
 843 {
 844         int status;
 845         struct dlm_cancel_join cancel_msg;
 846
 847         memset(&cancel_msg, 0, sizeof(cancel_msg));
 848         cancel_msg.node_idx = dlm->node_num;
 849         cancel_msg.name_len = strlen(dlm->name);
 850         memcpy(cancel_msg.domain, dlm->name, cancel_msg.name_len);
 851
 852         status = o2net_send_message(DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
 853                                     &cancel_msg, sizeof(cancel_msg), node,
 854                                     NULL);
 855         if (status < 0) {
 856                 mlog_errno(status);
 857                 goto bail;
 858         }
 859
 860 bail:
 861         return status;
 862 }
 863
 864 /* map_size should be in bytes. */
 865 static int dlm_send_join_cancels(struct dlm_ctxt *dlm,
 866                                  unsigned long *node_map,
 867                                  unsigned int map_size)
 868 {
 869         int status, tmpstat;
 870         unsigned int node;
 871
 872         if (map_size != (BITS_TO_LONGS(O2NM_MAX_NODES) *
 873                          sizeof(unsigned long))) {
 874                 mlog(ML_ERROR,
 875                      "map_size %u != BITS_TO_LONGS(O2NM_MAX_NODES) %u\n",
 876                      map_size, BITS_TO_LONGS(O2NM_MAX_NODES));
 877                 return -EINVAL;
 878         }
 879
 880         status = 0;
 881         node = -1;
 882         while ((node = find_next_bit(node_map, O2NM_MAX_NODES,
 883                                      node + 1)) < O2NM_MAX_NODES) {
 884                 if (node == dlm->node_num)
 885                         continue;
 886
 887                 tmpstat = dlm_send_one_join_cancel(dlm, node);
 888                 if (tmpstat) {
 889                         mlog(ML_ERROR, "Error return %d cancelling join on "
 890                              "node %d\n", tmpstat, node);
 891                         if (!status)
 892                                 status = tmpstat;
 893                 }
 894         }
 895
 896         if (status)
 897                 mlog_errno(status);
 898         return status;
 899 }
 900
 901 static int dlm_request_join(struct dlm_ctxt *dlm,
 902                             int node,
 903                             enum dlm_query_join_response *response)
 904 {
 905         int status, retval;
 906         struct dlm_query_join_request join_msg;
 907
 908         mlog(0, "querying node %d\n", node);
 909
 910         memset(&join_msg, 0, sizeof(join_msg));
 911         join_msg.node_idx = dlm->node_num;
 912         join_msg.name_len = strlen(dlm->name);
 913         memcpy(join_msg.domain, dlm->name, join_msg.name_len);
 914
 915         /* copy live node map to join message */
 916         byte_copymap(join_msg.node_map, dlm->live_nodes_map, O2NM_MAX_NODES);
 917
 918         status = o2net_send_message(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY, &join_msg,
 919                                     sizeof(join_msg), node, &retval);
 920         if (status < 0 && status != -ENOPROTOOPT) {
 921                 mlog_errno(status);
 922                 goto bail;
 923         }
 924
 925         /* -ENOPROTOOPT from the net code means the other side isn't
 926             listening for our message type -- that's fine, it means
 927             his dlm isn't up, so we can consider him a 'yes' but not
 928             joined into the domain.  */
 929         if (status == -ENOPROTOOPT) {
 930                 status = 0;
 931                 *response = JOIN_OK_NO_MAP;
 932         } else if (retval == JOIN_DISALLOW ||
 933                    retval == JOIN_OK ||
 934                    retval == JOIN_OK_NO_MAP) {
 935                 *response = retval;
 936         } else {
 937                 status = -EINVAL;
 938                 mlog(ML_ERROR, "invalid response %d from node %u\n", retval,
 939                      node);
 940         }
 941
 942         mlog(0, "status %d, node %d response is %d\n", status, node,
 943                   *response);
 944
 945 bail:
 946         return status;
 947 }
 948
 949 static int dlm_send_one_join_assert(struct dlm_ctxt *dlm,
 950                                     unsigned int node)
 951 {
 952         int status;
 953         struct dlm_assert_joined assert_msg;
 954
 955         mlog(0, "Sending join assert to node %u\n", node);
 956
 957         memset(&assert_msg, 0, sizeof(assert_msg));
 958         assert_msg.node_idx = dlm->node_num;
 959         assert_msg.name_len = strlen(dlm->name);
 960         memcpy(assert_msg.domain, dlm->name, assert_msg.name_len);
 961
 962         status = o2net_send_message(DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
 963                                     &assert_msg, sizeof(assert_msg), node,
 964                                     NULL);
 965         if (status < 0)
 966                 mlog_errno(status);
 967
 968         return status;
 969 }
 970
 971 static void dlm_send_join_asserts(struct dlm_ctxt *dlm,
 972                                   unsigned long *node_map)
 973 {
 974         int status, node, live;
 975
 976         status = 0;
 977         node = -1;
 978         while ((node = find_next_bit(node_map, O2NM_MAX_NODES,
 979                                      node + 1)) < O2NM_MAX_NODES) {
 980                 if (node == dlm->node_num)
 981                         continue;
 982
 983                 do {
 984                         /* It is very important that this message be
 985                          * received so we spin until either the node
 986                          * has died or it gets the message. */
 987                         status = dlm_send_one_join_assert(dlm, node);
 988
 989                         spin_lock(&dlm->spinlock);
 990                         live = test_bit(node, dlm->live_nodes_map);
 991                         spin_unlock(&dlm->spinlock);
 992
 993                         if (status) {
 994                                 mlog(ML_ERROR, "Error return %d asserting "
 995                                      "join on node %d\n", status, node);
 996
 997                                 /* give us some time between errors... */
 998                                 if (live)
 999                                         msleep(DLM_DOMAIN_BACKOFF_MS);
1000                         }
1001                 } while (status && live);
1002         }
1003 }
1004
1005 struct domain_join_ctxt {
1006         unsigned long live_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1007         unsigned long yes_resp_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1008 };
1009
1010 static int dlm_should_restart_join(struct dlm_ctxt *dlm,
1011                                    struct domain_join_ctxt *ctxt,
1012                                    enum dlm_query_join_response response)
1013 {
1014         int ret;
1015
1016         if (response == JOIN_DISALLOW) {
1017                 mlog(0, "Latest response of disallow -- should restart\n");
1018                 return 1;
1019         }
1020
1021         spin_lock(&dlm->spinlock);
1022         /* For now, we restart the process if the node maps have
1023          * changed at all */
1024         ret = memcmp(ctxt->live_map, dlm->live_nodes_map,
1025                      sizeof(dlm->live_nodes_map));
1026         spin_unlock(&dlm->spinlock);
1027
1028         if (ret)
1029                 mlog(0, "Node maps changed -- should restart\n");
1030
1031         return ret;
1032 }
1033
1034 static int dlm_try_to_join_domain(struct dlm_ctxt *dlm)
1035 {
1036         int status = 0, tmpstat, node;
1037         struct domain_join_ctxt *ctxt;
1038         enum dlm_query_join_response response;
1039
1040         mlog_entry("%p", dlm);
1041
1042         ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL);
1043         if (!ctxt) {
1044                 status = -ENOMEM;
1045                 mlog_errno(status);
1046                 goto bail;
1047         }
1048
1049         /* group sem locking should work for us here -- we're already
1050          * registered for heartbeat events so filling this should be
1051          * atomic wrt getting those handlers called. */
1052         o2hb_fill_node_map(dlm->live_nodes_map, sizeof(dlm->live_nodes_map));
1053
1054         spin_lock(&dlm->spinlock);
1055         memcpy(ctxt->live_map, dlm->live_nodes_map, sizeof(ctxt->live_map));
1056
1057         __dlm_set_joining_node(dlm, dlm->node_num);
1058
1059         spin_unlock(&dlm->spinlock);
1060
1061         node = -1;
1062         while ((node = find_next_bit(ctxt->live_map, O2NM_MAX_NODES,
1063                                      node + 1)) < O2NM_MAX_NODES) {
1064                 if (node == dlm->node_num)
1065                         continue;
1066
1067                 status = dlm_request_join(dlm, node, &response);
1068                 if (status < 0) {
1069                         mlog_errno(status);
1070                         goto bail;
1071                 }
1072
1073                 /* Ok, either we got a response or the node doesn't have a
1074                  * dlm up. */
1075                 if (response == JOIN_OK)
1076                         set_bit(node, ctxt->yes_resp_map);
1077
1078                 if (dlm_should_restart_join(dlm, ctxt, response)) {
1079                         status = -EAGAIN;
1080                         goto bail;
1081                 }
1082         }
1083
1084         mlog(0, "Yay, done querying nodes!\n");
1085
1086         /* Yay, everyone agree's we can join the domain. My domain is
1087          * comprised of all nodes who were put in the
1088          * yes_resp_map. Copy that into our domain map and send a join
1089          * assert message to clean up everyone elses state. */
1090         spin_lock(&dlm->spinlock);
1091         memcpy(dlm->domain_map, ctxt->yes_resp_map,
1092                sizeof(ctxt->yes_resp_map));
1093         set_bit(dlm->node_num, dlm->domain_map);
1094         spin_unlock(&dlm->spinlock);
1095
1096         dlm_send_join_asserts(dlm, ctxt->yes_resp_map);
1097
1098         /* Joined state *must* be set before the joining node
1099          * information, otherwise the query_join handler may read no
1100          * current joiner but a state of NEW and tell joining nodes
1101          * we're not in the domain. */
1102         spin_lock(&dlm_domain_lock);
1103         dlm->dlm_state = DLM_CTXT_JOINED;
1104         dlm->num_joins++;
1105         spin_unlock(&dlm_domain_lock);
1106
1107 bail:
1108         spin_lock(&dlm->spinlock);
1109         __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
1110         if (!status)
1111                 __dlm_print_nodes(dlm);
1112         spin_unlock(&dlm->spinlock);
1113
1114         if (ctxt) {
1115                 /* Do we need to send a cancel message to any nodes? */
1116                 if (status < 0) {
1117                         tmpstat = dlm_send_join_cancels(dlm,
1118                                                         ctxt->yes_resp_map,
1119                                                         sizeof(ctxt->yes_resp_map));
1120                         if (tmpstat < 0)
1121                                 mlog_errno(tmpstat);
1122                 }
1123                 kfree(ctxt);
1124         }
1125
1126         mlog(0, "returning %d\n", status);
1127         return status;
1128 }
1129
1130 static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm)
1131 {
1132         o2hb_unregister_callback(&dlm->dlm_hb_up);
1133         o2hb_unregister_callback(&dlm->dlm_hb_down);
1134         o2net_unregister_handler_list(&dlm->dlm_domain_handlers);
1135 }
1136
1137 static int dlm_register_domain_handlers(struct dlm_ctxt *dlm)
1138 {
1139         int status;
1140
1141         mlog(0, "registering handlers.\n");
1142
1143         o2hb_setup_callback(&dlm->dlm_hb_down, O2HB_NODE_DOWN_CB,
1144                             dlm_hb_node_down_cb, dlm, DLM_HB_NODE_DOWN_PRI);
1145         status = o2hb_register_callback(&dlm->dlm_hb_down);
1146         if (status)
1147                 goto bail;
1148
1149         o2hb_setup_callback(&dlm->dlm_hb_up, O2HB_NODE_UP_CB,
1150                             dlm_hb_node_up_cb, dlm, DLM_HB_NODE_UP_PRI);
1151         status = o2hb_register_callback(&dlm->dlm_hb_up);
1152         if (status)
1153                 goto bail;
1154
1155         status = o2net_register_handler(DLM_MASTER_REQUEST_MSG, dlm->key,
1156                                         sizeof(struct dlm_master_request),
1157                                         dlm_master_request_handler,
1158                                         dlm, NULL, &dlm->dlm_domain_handlers);
1159         if (status)
1160                 goto bail;
1161
1162         status = o2net_register_handler(DLM_ASSERT_MASTER_MSG, dlm->key,
1163                                         sizeof(struct dlm_assert_master),
1164                                         dlm_assert_master_handler,
1165                                         dlm, dlm_assert_master_post_handler,
1166                                         &dlm->dlm_domain_handlers);
1167         if (status)
1168                 goto bail;
1169
1170         status = o2net_register_handler(DLM_CREATE_LOCK_MSG, dlm->key,
1171                                         sizeof(struct dlm_create_lock),
1172                                         dlm_create_lock_handler,
1173                                         dlm, NULL, &dlm->dlm_domain_handlers);
1174         if (status)
1175                 goto bail;
1176
1177         status = o2net_register_handler(DLM_CONVERT_LOCK_MSG, dlm->key,
1178                                         DLM_CONVERT_LOCK_MAX_LEN,
1179                                         dlm_convert_lock_handler,
1180                                         dlm, NULL, &dlm->dlm_domain_handlers);
1181         if (status)
1182                 goto bail;
1183
1184         status = o2net_register_handler(DLM_UNLOCK_LOCK_MSG, dlm->key,
1185                                         DLM_UNLOCK_LOCK_MAX_LEN,
1186                                         dlm_unlock_lock_handler,
1187                                         dlm, NULL, &dlm->dlm_domain_handlers);
1188         if (status)
1189                 goto bail;
1190
1191         status = o2net_register_handler(DLM_PROXY_AST_MSG, dlm->key,
1192                                         DLM_PROXY_AST_MAX_LEN,
1193                                         dlm_proxy_ast_handler,
1194                                         dlm, NULL, &dlm->dlm_domain_handlers);
1195         if (status)
1196                 goto bail;
1197
1198         status = o2net_register_handler(DLM_EXIT_DOMAIN_MSG, dlm->key,
1199                                         sizeof(struct dlm_exit_domain),
1200                                         dlm_exit_domain_handler,
1201                                         dlm, NULL, &dlm->dlm_domain_handlers);
1202         if (status)
1203                 goto bail;
1204
1205         status = o2net_register_handler(DLM_DEREF_LOCKRES_MSG, dlm->key,
1206                                         sizeof(struct dlm_deref_lockres),
1207                                         dlm_deref_lockres_handler,
1208                                         dlm, NULL, &dlm->dlm_domain_handlers);
1209         if (status)
1210                 goto bail;
1211
1212         status = o2net_register_handler(DLM_MIGRATE_REQUEST_MSG, dlm->key,
1213                                         sizeof(struct dlm_migrate_request),
1214                                         dlm_migrate_request_handler,
1215                                         dlm, NULL, &dlm->dlm_domain_handlers);
1216         if (status)
1217                 goto bail;
1218
1219         status = o2net_register_handler(DLM_MIG_LOCKRES_MSG, dlm->key,
1220                                         DLM_MIG_LOCKRES_MAX_LEN,
1221                                         dlm_mig_lockres_handler,
1222                                         dlm, NULL, &dlm->dlm_domain_handlers);
1223         if (status)
1224                 goto bail;
1225
1226         status = o2net_register_handler(DLM_MASTER_REQUERY_MSG, dlm->key,
1227                                         sizeof(struct dlm_master_requery),
1228                                         dlm_master_requery_handler,
1229                                         dlm, NULL, &dlm->dlm_domain_handlers);
1230         if (status)
1231                 goto bail;
1232
1233         status = o2net_register_handler(DLM_LOCK_REQUEST_MSG, dlm->key,
1234                                         sizeof(struct dlm_lock_request),
1235                                         dlm_request_all_locks_handler,
1236                                         dlm, NULL, &dlm->dlm_domain_handlers);
1237         if (status)
1238                 goto bail;
1239
1240         status = o2net_register_handler(DLM_RECO_DATA_DONE_MSG, dlm->key,
1241                                         sizeof(struct dlm_reco_data_done),
1242                                         dlm_reco_data_done_handler,
1243                                         dlm, NULL, &dlm->dlm_domain_handlers);
1244         if (status)
1245                 goto bail;
1246
1247         status = o2net_register_handler(DLM_BEGIN_RECO_MSG, dlm->key,
1248                                         sizeof(struct dlm_begin_reco),
1249                                         dlm_begin_reco_handler,
1250                                         dlm, NULL, &dlm->dlm_domain_handlers);
1251         if (status)
1252                 goto bail;
1253
1254         status = o2net_register_handler(DLM_FINALIZE_RECO_MSG, dlm->key,
1255                                         sizeof(struct dlm_finalize_reco),
1256                                         dlm_finalize_reco_handler,
1257                                         dlm, NULL, &dlm->dlm_domain_handlers);
1258         if (status)
1259                 goto bail;
1260
1261 bail:
1262         if (status)
1263                 dlm_unregister_domain_handlers(dlm);
1264
1265         return status;
1266 }
1267
1268 static int dlm_join_domain(struct dlm_ctxt *dlm)
1269 {
1270         int status;
1271         unsigned int backoff;
1272         unsigned int total_backoff = 0;
1273
1274         BUG_ON(!dlm);
1275
1276         mlog(0, "Join domain %s\n", dlm->name);
1277
1278         status = dlm_register_domain_handlers(dlm);
1279         if (status) {
1280                 mlog_errno(status);
1281                 goto bail;
1282         }
1283
1284         status = dlm_launch_thread(dlm);
1285         if (status < 0) {
1286                 mlog_errno(status);
1287                 goto bail;
1288         }
1289
1290         status = dlm_launch_recovery_thread(dlm);
1291         if (status < 0) {
1292                 mlog_errno(status);
1293                 goto bail;
1294         }
1295
1296         dlm->dlm_worker = create_singlethread_workqueue("dlm_wq");
1297         if (!dlm->dlm_worker) {
1298                 status = -ENOMEM;
1299                 mlog_errno(status);
1300                 goto bail;
1301         }
1302
1303         do {
1304                 status = dlm_try_to_join_domain(dlm);
1305
1306                 /* If we're racing another node to the join, then we
1307                  * need to back off temporarily and let them
1308                  * complete. */
1309 #define DLM_JOIN_TIMEOUT_MSECS  90000
1310                 if (status == -EAGAIN) {
1311                         if (signal_pending(current)) {
1312                                 status = -ERESTARTSYS;
1313                                 goto bail;
1314                         }
1315
1316                         if (total_backoff >
1317                             msecs_to_jiffies(DLM_JOIN_TIMEOUT_MSECS)) {
1318                                 status = -ERESTARTSYS;
1319                                 mlog(ML_NOTICE, "Timed out joining dlm domain "
1320                                      "%s after %u msecs\n", dlm->name,
1321                                      jiffies_to_msecs(total_backoff));
1322                                 goto bail;
1323                         }
1324
1325                         /*
1326                          * <chip> After you!
1327                          * <dale> No, after you!
1328                          * <chip> I insist!
1329                          * <dale> But you first!
1330                          * ...
1331                          */
1332                         backoff = (unsigned int)(jiffies & 0x3);
1333                         backoff *= DLM_DOMAIN_BACKOFF_MS;
1334                         total_backoff += backoff;
1335                         mlog(0, "backoff %d\n", backoff);
1336                         msleep(backoff);
1337                 }
1338         } while (status == -EAGAIN);
1339
1340         if (status < 0) {
1341                 mlog_errno(status);
1342                 goto bail;
1343         }
1344
1345         status = 0;
1346 bail:
1347         wake_up(&dlm_domain_events);
1348
1349         if (status) {
1350                 dlm_unregister_domain_handlers(dlm);
1351                 dlm_complete_thread(dlm);
1352                 dlm_complete_recovery_thread(dlm);
1353                 dlm_destroy_dlm_worker(dlm);
1354         }
1355
1356         return status;
1357 }
1358
1359 static struct dlm_ctxt *dlm_alloc_ctxt(const char *domain,
1360                                 u32 key)
1361 {
1362         int i;
1363         struct dlm_ctxt *dlm = NULL;
1364
1365         dlm = kzalloc(sizeof(*dlm), GFP_KERNEL);
1366         if (!dlm) {
1367                 mlog_errno(-ENOMEM);
1368                 goto leave;
1369         }
1370
1371         dlm->name = kmalloc(strlen(domain) + 1, GFP_KERNEL);
1372         if (dlm->name == NULL) {
1373                 mlog_errno(-ENOMEM);
1374                 kfree(dlm);
1375                 dlm = NULL;
1376                 goto leave;
1377         }
1378
1379         dlm->lockres_hash = (struct hlist_head **)dlm_alloc_pagevec(DLM_HASH_PAGES);
1380         if (!dlm->lockres_hash) {
1381                 mlog_errno(-ENOMEM);
1382                 kfree(dlm->name);
1383                 kfree(dlm);
1384                 dlm = NULL;
1385                 goto leave;
1386         }
1387
1388         for (i = 0; i < DLM_HASH_BUCKETS; i++)
1389                 INIT_HLIST_HEAD(dlm_lockres_hash(dlm, i));
1390
1391         strcpy(dlm->name, domain);
1392         dlm->key = key;
1393         dlm->node_num = o2nm_this_node();
1394
1395         spin_lock_init(&dlm->spinlock);
1396         spin_lock_init(&dlm->master_lock);
1397         spin_lock_init(&dlm->ast_lock);
1398         INIT_LIST_HEAD(&dlm->list);
1399         INIT_LIST_HEAD(&dlm->dirty_list);
1400         INIT_LIST_HEAD(&dlm->reco.resources);
1401         INIT_LIST_HEAD(&dlm->reco.received);
1402         INIT_LIST_HEAD(&dlm->reco.node_data);
1403         INIT_LIST_HEAD(&dlm->purge_list);
1404         INIT_LIST_HEAD(&dlm->dlm_domain_handlers);
1405         dlm->reco.state = 0;
1406
1407         INIT_LIST_HEAD(&dlm->pending_asts);
1408         INIT_LIST_HEAD(&dlm->pending_basts);
1409
1410         mlog(0, "dlm->recovery_map=%p, &(dlm->recovery_map[0])=%p\n",
1411                   dlm->recovery_map, &(dlm->recovery_map[0]));
1412
1413         memset(dlm->recovery_map, 0, sizeof(dlm->recovery_map));
1414         memset(dlm->live_nodes_map, 0, sizeof(dlm->live_nodes_map));
1415         memset(dlm->domain_map, 0, sizeof(dlm->domain_map));
1416
1417         dlm->dlm_thread_task = NULL;
1418         dlm->dlm_reco_thread_task = NULL;
1419         dlm->dlm_worker = NULL;
1420         init_waitqueue_head(&dlm->dlm_thread_wq);
1421         init_waitqueue_head(&dlm->dlm_reco_thread_wq);
1422         init_waitqueue_head(&dlm->reco.event);
1423         init_waitqueue_head(&dlm->ast_wq);
1424         init_waitqueue_head(&dlm->migration_wq);
1425         INIT_LIST_HEAD(&dlm->master_list);
1426         INIT_LIST_HEAD(&dlm->mle_hb_events);
1427
1428         dlm->joining_node = DLM_LOCK_RES_OWNER_UNKNOWN;
1429         init_waitqueue_head(&dlm->dlm_join_events);
1430
1431         dlm->reco.new_master = O2NM_INVALID_NODE_NUM;
1432         dlm->reco.dead_node = O2NM_INVALID_NODE_NUM;
1433         atomic_set(&dlm->local_resources, 0);
1434         atomic_set(&dlm->remote_resources, 0);
1435         atomic_set(&dlm->unknown_resources, 0);
1436
1437         spin_lock_init(&dlm->work_lock);
1438         INIT_LIST_HEAD(&dlm->work_list);
1439         INIT_WORK(&dlm->dispatched_work, dlm_dispatch_work);
1440
1441         kref_init(&dlm->dlm_refs);
1442         dlm->dlm_state = DLM_CTXT_NEW;
1443
1444         INIT_LIST_HEAD(&dlm->dlm_eviction_callbacks);
1445
1446         mlog(0, "context init: refcount %u\n",
1447                   atomic_read(&dlm->dlm_refs.refcount));
1448
1449 leave:
1450         return dlm;
1451 }
1452
1453 /*
1454  * dlm_register_domain: one-time setup per "domain"
1455  */
1456 struct dlm_ctxt * dlm_register_domain(const char *domain,
1457                                u32 key)
1458 {
1459         int ret;
1460         struct dlm_ctxt *dlm = NULL;
1461         struct dlm_ctxt *new_ctxt = NULL;
1462
1463         if (strlen(domain) > O2NM_MAX_NAME_LEN) {
1464                 ret = -ENAMETOOLONG;
1465                 mlog(ML_ERROR, "domain name length too long\n");
1466                 goto leave;
1467         }
1468
1469         if (!o2hb_check_local_node_heartbeating()) {
1470                 mlog(ML_ERROR, "the local node has not been configured, or is "
1471                      "not heartbeating\n");
1472                 ret = -EPROTO;
1473                 goto leave;
1474         }
1475
1476         mlog(0, "register called for domain \"%s\"\n", domain);
1477
1478 retry:
1479         dlm = NULL;
1480         if (signal_pending(current)) {
1481                 ret = -ERESTARTSYS;
1482                 mlog_errno(ret);
1483                 goto leave;
1484         }
1485
1486         spin_lock(&dlm_domain_lock);
1487
1488         dlm = __dlm_lookup_domain(domain);
1489         if (dlm) {
1490                 if (dlm->dlm_state != DLM_CTXT_JOINED) {
1491                         spin_unlock(&dlm_domain_lock);
1492
1493                         mlog(0, "This ctxt is not joined yet!\n");
1494                         wait_event_interruptible(dlm_domain_events,
1495                                                  dlm_wait_on_domain_helper(
1496                                                          domain));
1497                         goto retry;
1498                 }
1499
1500                 __dlm_get(dlm);
1501                 dlm->num_joins++;
1502
1503                 spin_unlock(&dlm_domain_lock);
1504
1505                 ret = 0;
1506                 goto leave;
1507         }
1508
1509         /* doesn't exist */
1510         if (!new_ctxt) {
1511                 spin_unlock(&dlm_domain_lock);
1512
1513                 new_ctxt = dlm_alloc_ctxt(domain, key);
1514                 if (new_ctxt)
1515                         goto retry;
1516
1517                 ret = -ENOMEM;
1518                 mlog_errno(ret);
1519                 goto leave;
1520         }
1521
1522         /* a little variable switch-a-roo here... */
1523         dlm = new_ctxt;
1524         new_ctxt = NULL;
1525
1526         /* add the new domain */
1527         list_add_tail(&dlm->list, &dlm_domains);
1528         spin_unlock(&dlm_domain_lock);
1529
1530         ret = dlm_join_domain(dlm);
1531         if (ret) {
1532                 mlog_errno(ret);
1533                 dlm_put(dlm);
1534                 goto leave;
1535         }
1536
1537         ret = 0;
1538 leave:
1539         if (new_ctxt)
1540                 dlm_free_ctxt_mem(new_ctxt);
1541
1542         if (ret < 0)
1543                 dlm = ERR_PTR(ret);
1544
1545         return dlm;
1546 }
1547 EXPORT_SYMBOL_GPL(dlm_register_domain);
1548
1549 static LIST_HEAD(dlm_join_handlers);
1550
1551 static void dlm_unregister_net_handlers(void)
1552 {
1553         o2net_unregister_handler_list(&dlm_join_handlers);
1554 }
1555
1556 static int dlm_register_net_handlers(void)
1557 {
1558         int status = 0;
1559
1560         status = o2net_register_handler(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY,
1561                                         sizeof(struct dlm_query_join_request),
1562                                         dlm_query_join_handler,
1563                                         NULL, NULL, &dlm_join_handlers);
1564         if (status)
1565                 goto bail;
1566
1567         status = o2net_register_handler(DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
1568                                         sizeof(struct dlm_assert_joined),
1569                                         dlm_assert_joined_handler,
1570                                         NULL, NULL, &dlm_join_handlers);
1571         if (status)
1572                 goto bail;
1573
1574         status = o2net_register_handler(DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
1575                                         sizeof(struct dlm_cancel_join),
1576                                         dlm_cancel_join_handler,
1577                                         NULL, NULL, &dlm_join_handlers);
1578
1579 bail:
1580         if (status < 0)
1581                 dlm_unregister_net_handlers();
1582
1583         return status;
1584 }
1585
1586 /* Domain eviction callback handling.
1587  *
1588  * The file system requires notification of node death *before* the
1589  * dlm completes it's recovery work, otherwise it may be able to
1590  * acquire locks on resources requiring recovery. Since the dlm can
1591  * evict a node from it's domain *before* heartbeat fires, a similar
1592  * mechanism is required. */
1593
1594 /* Eviction is not expected to happen often, so a per-domain lock is
1595  * not necessary. Eviction callbacks are allowed to sleep for short
1596  * periods of time. */
1597 static DECLARE_RWSEM(dlm_callback_sem);
1598
1599 void dlm_fire_domain_eviction_callbacks(struct dlm_ctxt *dlm,
1600                                         int node_num)
1601 {
1602         struct list_head *iter;
1603         struct dlm_eviction_cb *cb;
1604
1605         down_read(&dlm_callback_sem);
1606         list_for_each(iter, &dlm->dlm_eviction_callbacks) {
1607                 cb = list_entry(iter, struct dlm_eviction_cb, ec_item);
1608
1609                 cb->ec_func(node_num, cb->ec_data);
1610         }
1611         up_read(&dlm_callback_sem);
1612 }
1613
1614 void dlm_setup_eviction_cb(struct dlm_eviction_cb *cb,
1615                            dlm_eviction_func *f,
1616                            void *data)
1617 {
1618         INIT_LIST_HEAD(&cb->ec_item);
1619         cb->ec_func = f;
1620         cb->ec_data = data;
1621 }
1622 EXPORT_SYMBOL_GPL(dlm_setup_eviction_cb);
1623
1624 void dlm_register_eviction_cb(struct dlm_ctxt *dlm,
1625                               struct dlm_eviction_cb *cb)
1626 {
1627         down_write(&dlm_callback_sem);
1628         list_add_tail(&cb->ec_item, &dlm->dlm_eviction_callbacks);
1629         up_write(&dlm_callback_sem);
1630 }
1631 EXPORT_SYMBOL_GPL(dlm_register_eviction_cb);
1632
1633 void dlm_unregister_eviction_cb(struct dlm_eviction_cb *cb)
1634 {
1635         down_write(&dlm_callback_sem);
1636         list_del_init(&cb->ec_item);
1637         up_write(&dlm_callback_sem);
1638 }
1639 EXPORT_SYMBOL_GPL(dlm_unregister_eviction_cb);
1640
1641 static int __init dlm_init(void)
1642 {
1643         int status;
1644
1645         dlm_print_version();
1646
1647         status = dlm_init_mle_cache();
1648         if (status)
1649                 return -1;
1650
1651         status = dlm_register_net_handlers();
1652         if (status) {
1653                 dlm_destroy_mle_cache();
1654                 return -1;
1655         }
1656
1657         return 0;
1658 }
1659
1660 static void __exit dlm_exit (void)
1661 {
1662         dlm_unregister_net_handlers();
1663         dlm_destroy_mle_cache();
1664 }
1665
1666 MODULE_AUTHOR("Oracle");
1667 MODULE_LICENSE("GPL");
1668
1669 module_init(dlm_init);
1670 module_exit(dlm_exit);