kernel/fs/ocfs2/dlm/dlmmaster.c

   1 /* -*- mode: c; c-basic-offset: 8; -*-
   2  * vim: noexpandtab sw=8 ts=8 sts=0:
   3  *
   4  * dlmmod.c
   5  *
   6  * standalone DLM module
   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
  28 #include <linux/module.h>
  29 #include <linux/fs.h>
  30 #include <linux/types.h>
  31 #include <linux/slab.h>
  32 #include <linux/highmem.h>
  33 #include <linux/init.h>
  34 #include <linux/sysctl.h>
  35 #include <linux/random.h>
  36 #include <linux/blkdev.h>
  37 #include <linux/socket.h>
  38 #include <linux/inet.h>
  39 #include <linux/spinlock.h>
  40 #include <linux/delay.h>
  41
  42
  43 #include "cluster/heartbeat.h"
  44 #include "cluster/nodemanager.h"
  45 #include "cluster/tcp.h"
  46
  47 #include "dlmapi.h"
  48 #include "dlmcommon.h"
  49 #include "dlmdomain.h"
  50 #include "dlmdebug.h"
  51
  52 #define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_MASTER)
  53 #include "cluster/masklog.h"
  54
  55 static void dlm_mle_node_down(struct dlm_ctxt *dlm,
  56                               struct dlm_master_list_entry *mle,
  57                               struct o2nm_node *node,
  58                               int idx);
  59 static void dlm_mle_node_up(struct dlm_ctxt *dlm,
  60                             struct dlm_master_list_entry *mle,
  61                             struct o2nm_node *node,
  62                             int idx);
  63
  64 static void dlm_assert_master_worker(struct dlm_work_item *item, void *data);
  65 static int dlm_do_assert_master(struct dlm_ctxt *dlm,
  66                                 struct dlm_lock_resource *res,
  67                                 void *nodemap, u32 flags);
  68 static void dlm_deref_lockres_worker(struct dlm_work_item *item, void *data);
  69
  70 static inline int dlm_mle_equal(struct dlm_ctxt *dlm,
  71                                 struct dlm_master_list_entry *mle,
  72                                 const char *name,
  73                                 unsigned int namelen)
  74 {
  75         if (dlm != mle->dlm)
  76                 return 0;
  77
  78         if (namelen != mle->mnamelen ||
  79             memcmp(name, mle->mname, namelen) != 0)
  80                 return 0;
  81
  82         return 1;
  83 }
  84
  85 static struct kmem_cache *dlm_lockres_cache;
  86 static struct kmem_cache *dlm_lockname_cache;
  87 static struct kmem_cache *dlm_mle_cache;
  88
  89 static void dlm_mle_release(struct kref *kref);
  90 static void dlm_init_mle(struct dlm_master_list_entry *mle,
  91                         enum dlm_mle_type type,
  92                         struct dlm_ctxt *dlm,
  93                         struct dlm_lock_resource *res,
  94                         const char *name,
  95                         unsigned int namelen);
  96 static void dlm_put_mle(struct dlm_master_list_entry *mle);
  97 static void __dlm_put_mle(struct dlm_master_list_entry *mle);
  98 static int dlm_find_mle(struct dlm_ctxt *dlm,
  99                         struct dlm_master_list_entry **mle,
 100                         char *name, unsigned int namelen);
 101
 102 static int dlm_do_master_request(struct dlm_lock_resource *res,
 103                                  struct dlm_master_list_entry *mle, int to);
 104
 105
 106 static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
 107                                      struct dlm_lock_resource *res,
 108                                      struct dlm_master_list_entry *mle,
 109                                      int *blocked);
 110 static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
 111                                     struct dlm_lock_resource *res,
 112                                     struct dlm_master_list_entry *mle,
 113                                     int blocked);
 114 static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
 115                                  struct dlm_lock_resource *res,
 116                                  struct dlm_master_list_entry *mle,
 117                                  struct dlm_master_list_entry **oldmle,
 118                                  const char *name, unsigned int namelen,
 119                                  u8 new_master, u8 master);
 120
 121 static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
 122                                     struct dlm_lock_resource *res);
 123 static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
 124                                       struct dlm_lock_resource *res);
 125 static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
 126                                        struct dlm_lock_resource *res,
 127                                        u8 target);
 128 static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
 129                                        struct dlm_lock_resource *res);
 130
 131
 132 int dlm_is_host_down(int errno)
 133 {
 134         switch (errno) {
 135                 case -EBADF:
 136                 case -ECONNREFUSED:
 137                 case -ENOTCONN:
 138                 case -ECONNRESET:
 139                 case -EPIPE:
 140                 case -EHOSTDOWN:
 141                 case -EHOSTUNREACH:
 142                 case -ETIMEDOUT:
 143                 case -ECONNABORTED:
 144                 case -ENETDOWN:
 145                 case -ENETUNREACH:
 146                 case -ENETRESET:
 147                 case -ESHUTDOWN:
 148                 case -ENOPROTOOPT:
 149                 case -EINVAL:   /* if returned from our tcp code,
 150                                    this means there is no socket */
 151                         return 1;
 152         }
 153         return 0;
 154 }
 155
 156
 157 /*
 158  * MASTER LIST FUNCTIONS
 159  */
 160
 161
 162 /*
 163  * regarding master list entries and heartbeat callbacks:
 164  *
 165  * in order to avoid sleeping and allocation that occurs in
 166  * heartbeat, master list entries are simply attached to the
 167  * dlm's established heartbeat callbacks.  the mle is attached
 168  * when it is created, and since the dlm->spinlock is held at
 169  * that time, any heartbeat event will be properly discovered
 170  * by the mle.  the mle needs to be detached from the
 171  * dlm->mle_hb_events list as soon as heartbeat events are no
 172  * longer useful to the mle, and before the mle is freed.
 173  *
 174  * as a general rule, heartbeat events are no longer needed by
 175  * the mle once an "answer" regarding the lock master has been
 176  * received.
 177  */
 178 static inline void __dlm_mle_attach_hb_events(struct dlm_ctxt *dlm,
 179                                               struct dlm_master_list_entry *mle)
 180 {
 181         assert_spin_locked(&dlm->spinlock);
 182
 183         list_add_tail(&mle->hb_events, &dlm->mle_hb_events);
 184 }
 185
 186
 187 static inline void __dlm_mle_detach_hb_events(struct dlm_ctxt *dlm,
 188                                               struct dlm_master_list_entry *mle)
 189 {
 190         if (!list_empty(&mle->hb_events))
 191                 list_del_init(&mle->hb_events);
 192 }
 193
 194
 195 static inline void dlm_mle_detach_hb_events(struct dlm_ctxt *dlm,
 196                                             struct dlm_master_list_entry *mle)
 197 {
 198         spin_lock(&dlm->spinlock);
 199         __dlm_mle_detach_hb_events(dlm, mle);
 200         spin_unlock(&dlm->spinlock);
 201 }
 202
 203 static void dlm_get_mle_inuse(struct dlm_master_list_entry *mle)
 204 {
 205         struct dlm_ctxt *dlm;
 206         dlm = mle->dlm;
 207
 208         assert_spin_locked(&dlm->spinlock);
 209         assert_spin_locked(&dlm->master_lock);
 210         mle->inuse++;
 211         kref_get(&mle->mle_refs);
 212 }
 213
 214 static void dlm_put_mle_inuse(struct dlm_master_list_entry *mle)
 215 {
 216         struct dlm_ctxt *dlm;
 217         dlm = mle->dlm;
 218
 219         spin_lock(&dlm->spinlock);
 220         spin_lock(&dlm->master_lock);
 221         mle->inuse--;
 222         __dlm_put_mle(mle);
 223         spin_unlock(&dlm->master_lock);
 224         spin_unlock(&dlm->spinlock);
 225
 226 }
 227
 228 /* remove from list and free */
 229 static void __dlm_put_mle(struct dlm_master_list_entry *mle)
 230 {
 231         struct dlm_ctxt *dlm;
 232         dlm = mle->dlm;
 233
 234         assert_spin_locked(&dlm->spinlock);
 235         assert_spin_locked(&dlm->master_lock);
 236         if (!atomic_read(&mle->mle_refs.refcount)) {
 237                 /* this may or may not crash, but who cares.
 238                  * it's a BUG. */
 239                 mlog(ML_ERROR, "bad mle: %p\n", mle);
 240                 dlm_print_one_mle(mle);
 241                 BUG();
 242         } else
 243                 kref_put(&mle->mle_refs, dlm_mle_release);
 244 }
 245
 246
 247 /* must not have any spinlocks coming in */
 248 static void dlm_put_mle(struct dlm_master_list_entry *mle)
 249 {
 250         struct dlm_ctxt *dlm;
 251         dlm = mle->dlm;
 252
 253         spin_lock(&dlm->spinlock);
 254         spin_lock(&dlm->master_lock);
 255         __dlm_put_mle(mle);
 256         spin_unlock(&dlm->master_lock);
 257         spin_unlock(&dlm->spinlock);
 258 }
 259
 260 static inline void dlm_get_mle(struct dlm_master_list_entry *mle)
 261 {
 262         kref_get(&mle->mle_refs);
 263 }
 264
 265 static void dlm_init_mle(struct dlm_master_list_entry *mle,
 266                         enum dlm_mle_type type,
 267                         struct dlm_ctxt *dlm,
 268                         struct dlm_lock_resource *res,
 269                         const char *name,
 270                         unsigned int namelen)
 271 {
 272         assert_spin_locked(&dlm->spinlock);
 273
 274         mle->dlm = dlm;
 275         mle->type = type;
 276         INIT_HLIST_NODE(&mle->master_hash_node);
 277         INIT_LIST_HEAD(&mle->hb_events);
 278         memset(mle->maybe_map, 0, sizeof(mle->maybe_map));
 279         spin_lock_init(&mle->spinlock);
 280         init_waitqueue_head(&mle->wq);
 281         atomic_set(&mle->woken, 0);
 282         kref_init(&mle->mle_refs);
 283         memset(mle->response_map, 0, sizeof(mle->response_map));
 284         mle->master = O2NM_MAX_NODES;
 285         mle->new_master = O2NM_MAX_NODES;
 286         mle->inuse = 0;
 287
 288         BUG_ON(mle->type != DLM_MLE_BLOCK &&
 289                mle->type != DLM_MLE_MASTER &&
 290                mle->type != DLM_MLE_MIGRATION);
 291
 292         if (mle->type == DLM_MLE_MASTER) {
 293                 BUG_ON(!res);
 294                 mle->mleres = res;
 295                 memcpy(mle->mname, res->lockname.name, res->lockname.len);
 296                 mle->mnamelen = res->lockname.len;
 297                 mle->mnamehash = res->lockname.hash;
 298         } else {
 299                 BUG_ON(!name);
 300                 mle->mleres = NULL;
 301                 memcpy(mle->mname, name, namelen);
 302                 mle->mnamelen = namelen;
 303                 mle->mnamehash = dlm_lockid_hash(name, namelen);
 304         }
 305
 306         atomic_inc(&dlm->mle_tot_count[mle->type]);
 307         atomic_inc(&dlm->mle_cur_count[mle->type]);
 308
 309         /* copy off the node_map and register hb callbacks on our copy */
 310         memcpy(mle->node_map, dlm->domain_map, sizeof(mle->node_map));
 311         memcpy(mle->vote_map, dlm->domain_map, sizeof(mle->vote_map));
 312         clear_bit(dlm->node_num, mle->vote_map);
 313         clear_bit(dlm->node_num, mle->node_map);
 314
 315         /* attach the mle to the domain node up/down events */
 316         __dlm_mle_attach_hb_events(dlm, mle);
 317 }
 318
 319 void __dlm_unlink_mle(struct dlm_ctxt *dlm, struct dlm_master_list_entry *mle)
 320 {
 321         assert_spin_locked(&dlm->spinlock);
 322         assert_spin_locked(&dlm->master_lock);
 323
 324         if (!hlist_unhashed(&mle->master_hash_node))
 325                 hlist_del_init(&mle->master_hash_node);
 326 }
 327
 328 void __dlm_insert_mle(struct dlm_ctxt *dlm, struct dlm_master_list_entry *mle)
 329 {
 330         struct hlist_head *bucket;
 331
 332         assert_spin_locked(&dlm->master_lock);
 333
 334         bucket = dlm_master_hash(dlm, mle->mnamehash);
 335         hlist_add_head(&mle->master_hash_node, bucket);
 336 }
 337
 338 /* returns 1 if found, 0 if not */
 339 static int dlm_find_mle(struct dlm_ctxt *dlm,
 340                         struct dlm_master_list_entry **mle,
 341                         char *name, unsigned int namelen)
 342 {
 343         struct dlm_master_list_entry *tmpmle;
 344         struct hlist_head *bucket;
 345         unsigned int hash;
 346
 347         assert_spin_locked(&dlm->master_lock);
 348
 349         hash = dlm_lockid_hash(name, namelen);
 350         bucket = dlm_master_hash(dlm, hash);
 351         hlist_for_each_entry(tmpmle, bucket, master_hash_node) {
 352                 if (!dlm_mle_equal(dlm, tmpmle, name, namelen))
 353                         continue;
 354                 dlm_get_mle(tmpmle);
 355                 *mle = tmpmle;
 356                 return 1;
 357         }
 358         return 0;
 359 }
 360
 361 void dlm_hb_event_notify_attached(struct dlm_ctxt *dlm, int idx, int node_up)
 362 {
 363         struct dlm_master_list_entry *mle;
 364
 365         assert_spin_locked(&dlm->spinlock);
 366
 367         list_for_each_entry(mle, &dlm->mle_hb_events, hb_events) {
 368                 if (node_up)
 369                         dlm_mle_node_up(dlm, mle, NULL, idx);
 370                 else
 371                         dlm_mle_node_down(dlm, mle, NULL, idx);
 372         }
 373 }
 374
 375 static void dlm_mle_node_down(struct dlm_ctxt *dlm,
 376                               struct dlm_master_list_entry *mle,
 377                               struct o2nm_node *node, int idx)
 378 {
 379         spin_lock(&mle->spinlock);
 380
 381         if (!test_bit(idx, mle->node_map))
 382                 mlog(0, "node %u already removed from nodemap!\n", idx);
 383         else
 384                 clear_bit(idx, mle->node_map);
 385
 386         spin_unlock(&mle->spinlock);
 387 }
 388
 389 static void dlm_mle_node_up(struct dlm_ctxt *dlm,
 390                             struct dlm_master_list_entry *mle,
 391                             struct o2nm_node *node, int idx)
 392 {
 393         spin_lock(&mle->spinlock);
 394
 395         if (test_bit(idx, mle->node_map))
 396                 mlog(0, "node %u already in node map!\n", idx);
 397         else
 398                 set_bit(idx, mle->node_map);
 399
 400         spin_unlock(&mle->spinlock);
 401 }
 402
 403
 404 int dlm_init_mle_cache(void)
 405 {
 406         dlm_mle_cache = kmem_cache_create("o2dlm_mle",
 407                                           sizeof(struct dlm_master_list_entry),
 408                                           0, SLAB_HWCACHE_ALIGN,
 409                                           NULL);
 410         if (dlm_mle_cache == NULL)
 411                 return -ENOMEM;
 412         return 0;
 413 }
 414
 415 void dlm_destroy_mle_cache(void)
 416 {
 417         if (dlm_mle_cache)
 418                 kmem_cache_destroy(dlm_mle_cache);
 419 }
 420
 421 static void dlm_mle_release(struct kref *kref)
 422 {
 423         struct dlm_master_list_entry *mle;
 424         struct dlm_ctxt *dlm;
 425
 426         mle = container_of(kref, struct dlm_master_list_entry, mle_refs);
 427         dlm = mle->dlm;
 428
 429         assert_spin_locked(&dlm->spinlock);
 430         assert_spin_locked(&dlm->master_lock);
 431
 432         mlog(0, "Releasing mle for %.*s, type %d\n", mle->mnamelen, mle->mname,
 433              mle->type);
 434
 435         /* remove from list if not already */
 436         __dlm_unlink_mle(dlm, mle);
 437
 438         /* detach the mle from the domain node up/down events */
 439         __dlm_mle_detach_hb_events(dlm, mle);
 440
 441         atomic_dec(&dlm->mle_cur_count[mle->type]);
 442
 443         /* NOTE: kfree under spinlock here.
 444          * if this is bad, we can move this to a freelist. */
 445         kmem_cache_free(dlm_mle_cache, mle);
 446 }
 447
 448
 449 /*
 450  * LOCK RESOURCE FUNCTIONS
 451  */
 452
 453 int dlm_init_master_caches(void)
 454 {
 455         dlm_lockres_cache = kmem_cache_create("o2dlm_lockres",
 456                                               sizeof(struct dlm_lock_resource),
 457                                               0, SLAB_HWCACHE_ALIGN, NULL);
 458         if (!dlm_lockres_cache)
 459                 goto bail;
 460
 461         dlm_lockname_cache = kmem_cache_create("o2dlm_lockname",
 462                                                DLM_LOCKID_NAME_MAX, 0,
 463                                                SLAB_HWCACHE_ALIGN, NULL);
 464         if (!dlm_lockname_cache)
 465                 goto bail;
 466
 467         return 0;
 468 bail:
 469         dlm_destroy_master_caches();
 470         return -ENOMEM;
 471 }
 472
 473 void dlm_destroy_master_caches(void)
 474 {
 475         if (dlm_lockname_cache) {
 476                 kmem_cache_destroy(dlm_lockname_cache);
 477                 dlm_lockname_cache = NULL;
 478         }
 479
 480         if (dlm_lockres_cache) {
 481                 kmem_cache_destroy(dlm_lockres_cache);
 482                 dlm_lockres_cache = NULL;
 483         }
 484 }
 485
 486 static void dlm_lockres_release(struct kref *kref)
 487 {
 488         struct dlm_lock_resource *res;
 489         struct dlm_ctxt *dlm;
 490
 491         res = container_of(kref, struct dlm_lock_resource, refs);
 492         dlm = res->dlm;
 493
 494         /* This should not happen -- all lockres' have a name
 495          * associated with them at init time. */
 496         BUG_ON(!res->lockname.name);
 497
 498         mlog(0, "destroying lockres %.*s\n", res->lockname.len,
 499              res->lockname.name);
 500
 501         spin_lock(&dlm->track_lock);
 502         if (!list_empty(&res->tracking))
 503                 list_del_init(&res->tracking);
 504         else {
 505                 mlog(ML_ERROR, "Resource %.*s not on the Tracking list\n",
 506                      res->lockname.len, res->lockname.name);
 507                 dlm_print_one_lock_resource(res);
 508         }
 509         spin_unlock(&dlm->track_lock);
 510
 511         atomic_dec(&dlm->res_cur_count);
 512
 513         if (!hlist_unhashed(&res->hash_node) ||
 514             !list_empty(&res->granted) ||
 515             !list_empty(&res->converting) ||
 516             !list_empty(&res->blocked) ||
 517             !list_empty(&res->dirty) ||
 518             !list_empty(&res->recovering) ||
 519             !list_empty(&res->purge)) {
 520                 mlog(ML_ERROR,
 521                      "Going to BUG for resource %.*s."
 522                      "  We're on a list! [%c%c%c%c%c%c%c]\n",
 523                      res->lockname.len, res->lockname.name,
 524                      !hlist_unhashed(&res->hash_node) ? 'H' : ' ',
 525                      !list_empty(&res->granted) ? 'G' : ' ',
 526                      !list_empty(&res->converting) ? 'C' : ' ',
 527                      !list_empty(&res->blocked) ? 'B' : ' ',
 528                      !list_empty(&res->dirty) ? 'D' : ' ',
 529                      !list_empty(&res->recovering) ? 'R' : ' ',
 530                      !list_empty(&res->purge) ? 'P' : ' ');
 531
 532                 dlm_print_one_lock_resource(res);
 533         }
 534
 535         /* By the time we're ready to blow this guy away, we shouldn't
 536          * be on any lists. */
 537         BUG_ON(!hlist_unhashed(&res->hash_node));
 538         BUG_ON(!list_empty(&res->granted));
 539         BUG_ON(!list_empty(&res->converting));
 540         BUG_ON(!list_empty(&res->blocked));
 541         BUG_ON(!list_empty(&res->dirty));
 542         BUG_ON(!list_empty(&res->recovering));
 543         BUG_ON(!list_empty(&res->purge));
 544
 545         kmem_cache_free(dlm_lockname_cache, (void *)res->lockname.name);
 546
 547         kmem_cache_free(dlm_lockres_cache, res);
 548 }
 549
 550 void dlm_lockres_put(struct dlm_lock_resource *res)
 551 {
 552         kref_put(&res->refs, dlm_lockres_release);
 553 }
 554
 555 static void dlm_init_lockres(struct dlm_ctxt *dlm,
 556                              struct dlm_lock_resource *res,
 557                              const char *name, unsigned int namelen)
 558 {
 559         char *qname;
 560
 561         /* If we memset here, we lose our reference to the kmalloc'd
 562          * res->lockname.name, so be sure to init every field
 563          * correctly! */
 564
 565         qname = (char *) res->lockname.name;
 566         memcpy(qname, name, namelen);
 567
 568         res->lockname.len = namelen;
 569         res->lockname.hash = dlm_lockid_hash(name, namelen);
 570
 571         init_waitqueue_head(&res->wq);
 572         spin_lock_init(&res->spinlock);
 573         INIT_HLIST_NODE(&res->hash_node);
 574         INIT_LIST_HEAD(&res->granted);
 575         INIT_LIST_HEAD(&res->converting);
 576         INIT_LIST_HEAD(&res->blocked);
 577         INIT_LIST_HEAD(&res->dirty);
 578         INIT_LIST_HEAD(&res->recovering);
 579         INIT_LIST_HEAD(&res->purge);
 580         INIT_LIST_HEAD(&res->tracking);
 581         atomic_set(&res->asts_reserved, 0);
 582         res->migration_pending = 0;
 583         res->inflight_locks = 0;
 584         res->inflight_assert_workers = 0;
 585
 586         res->dlm = dlm;
 587
 588         kref_init(&res->refs);
 589
 590         atomic_inc(&dlm->res_tot_count);
 591         atomic_inc(&dlm->res_cur_count);
 592
 593         /* just for consistency */
 594         spin_lock(&res->spinlock);
 595         dlm_set_lockres_owner(dlm, res, DLM_LOCK_RES_OWNER_UNKNOWN);
 596         spin_unlock(&res->spinlock);
 597
 598         res->state = DLM_LOCK_RES_IN_PROGRESS;
 599
 600         res->last_used = 0;
 601
 602         spin_lock(&dlm->spinlock);
 603         list_add_tail(&res->tracking, &dlm->tracking_list);
 604         spin_unlock(&dlm->spinlock);
 605
 606         memset(res->lvb, 0, DLM_LVB_LEN);
 607         memset(res->refmap, 0, sizeof(res->refmap));
 608 }
 609
 610 struct dlm_lock_resource *dlm_new_lockres(struct dlm_ctxt *dlm,
 611                                    const char *name,
 612                                    unsigned int namelen)
 613 {
 614         struct dlm_lock_resource *res = NULL;
 615
 616         res = kmem_cache_zalloc(dlm_lockres_cache, GFP_NOFS);
 617         if (!res)
 618                 goto error;
 619
 620         res->lockname.name = kmem_cache_zalloc(dlm_lockname_cache, GFP_NOFS);
 621         if (!res->lockname.name)
 622                 goto error;
 623
 624         dlm_init_lockres(dlm, res, name, namelen);
 625         return res;
 626
 627 error:
 628         if (res)
 629                 kmem_cache_free(dlm_lockres_cache, res);
 630         return NULL;
 631 }
 632
 633 void dlm_lockres_set_refmap_bit(struct dlm_ctxt *dlm,
 634                                 struct dlm_lock_resource *res, int bit)
 635 {
 636         assert_spin_locked(&res->spinlock);
 637
 638         mlog(0, "res %.*s, set node %u, %ps()\n", res->lockname.len,
 639              res->lockname.name, bit, __builtin_return_address(0));
 640
 641         set_bit(bit, res->refmap);
 642 }
 643
 644 void dlm_lockres_clear_refmap_bit(struct dlm_ctxt *dlm,
 645                                   struct dlm_lock_resource *res, int bit)
 646 {
 647         assert_spin_locked(&res->spinlock);
 648
 649         mlog(0, "res %.*s, clr node %u, %ps()\n", res->lockname.len,
 650              res->lockname.name, bit, __builtin_return_address(0));
 651
 652         clear_bit(bit, res->refmap);
 653 }
 654
 655 static void __dlm_lockres_grab_inflight_ref(struct dlm_ctxt *dlm,
 656                                    struct dlm_lock_resource *res)
 657 {
 658         res->inflight_locks++;
 659
 660         mlog(0, "%s: res %.*s, inflight++: now %u, %ps()\n", dlm->name,
 661              res->lockname.len, res->lockname.name, res->inflight_locks,
 662              __builtin_return_address(0));
 663 }
 664
 665 void dlm_lockres_grab_inflight_ref(struct dlm_ctxt *dlm,
 666                                    struct dlm_lock_resource *res)
 667 {
 668         assert_spin_locked(&res->spinlock);
 669         __dlm_lockres_grab_inflight_ref(dlm, res);
 670 }
 671
 672 void dlm_lockres_drop_inflight_ref(struct dlm_ctxt *dlm,
 673                                    struct dlm_lock_resource *res)
 674 {
 675         assert_spin_locked(&res->spinlock);
 676
 677         BUG_ON(res->inflight_locks == 0);
 678
 679         res->inflight_locks--;
 680
 681         mlog(0, "%s: res %.*s, inflight--: now %u, %ps()\n", dlm->name,
 682              res->lockname.len, res->lockname.name, res->inflight_locks,
 683              __builtin_return_address(0));
 684
 685         wake_up(&res->wq);
 686 }
 687
 688 void __dlm_lockres_grab_inflight_worker(struct dlm_ctxt *dlm,
 689                 struct dlm_lock_resource *res)
 690 {
 691         assert_spin_locked(&res->spinlock);
 692         res->inflight_assert_workers++;
 693         mlog(0, "%s:%.*s: inflight assert worker++: now %u\n",
 694                         dlm->name, res->lockname.len, res->lockname.name,
 695                         res->inflight_assert_workers);
 696 }
 697
 698 static void __dlm_lockres_drop_inflight_worker(struct dlm_ctxt *dlm,
 699                 struct dlm_lock_resource *res)
 700 {
 701         assert_spin_locked(&res->spinlock);
 702         BUG_ON(res->inflight_assert_workers == 0);
 703         res->inflight_assert_workers--;
 704         mlog(0, "%s:%.*s: inflight assert worker--: now %u\n",
 705                         dlm->name, res->lockname.len, res->lockname.name,
 706                         res->inflight_assert_workers);
 707 }
 708
 709 static void dlm_lockres_drop_inflight_worker(struct dlm_ctxt *dlm,
 710                 struct dlm_lock_resource *res)
 711 {
 712         spin_lock(&res->spinlock);
 713         __dlm_lockres_drop_inflight_worker(dlm, res);
 714         spin_unlock(&res->spinlock);
 715 }
 716
 717 /*
 718  * lookup a lock resource by name.
 719  * may already exist in the hashtable.
 720  * lockid is null terminated
 721  *
 722  * if not, allocate enough for the lockres and for
 723  * the temporary structure used in doing the mastering.
 724  *
 725  * also, do a lookup in the dlm->master_list to see
 726  * if another node has begun mastering the same lock.
 727  * if so, there should be a block entry in there
 728  * for this name, and we should *not* attempt to master
 729  * the lock here.   need to wait around for that node
 730  * to assert_master (or die).
 731  *
 732  */
 733 struct dlm_lock_resource * dlm_get_lock_resource(struct dlm_ctxt *dlm,
 734                                           const char *lockid,
 735                                           int namelen,
 736                                           int flags)
 737 {
 738         struct dlm_lock_resource *tmpres=NULL, *res=NULL;
 739         struct dlm_master_list_entry *mle = NULL;
 740         struct dlm_master_list_entry *alloc_mle = NULL;
 741         int blocked = 0;
 742         int ret, nodenum;
 743         struct dlm_node_iter iter;
 744         unsigned int hash;
 745         int tries = 0;
 746         int bit, wait_on_recovery = 0;
 747
 748         BUG_ON(!lockid);
 749
 750         hash = dlm_lockid_hash(lockid, namelen);
 751
 752         mlog(0, "get lockres %s (len %d)\n", lockid, namelen);
 753
 754 lookup:
 755         spin_lock(&dlm->spinlock);
 756         tmpres = __dlm_lookup_lockres_full(dlm, lockid, namelen, hash);
 757         if (tmpres) {
 758                 spin_unlock(&dlm->spinlock);
 759                 spin_lock(&tmpres->spinlock);
 760
 761                 /*
 762                  * Right after dlm spinlock was released, dlm_thread could have
 763                  * purged the lockres. Check if lockres got unhashed. If so
 764                  * start over.
 765                  */
 766                 if (hlist_unhashed(&tmpres->hash_node)) {
 767                         spin_unlock(&tmpres->spinlock);
 768                         dlm_lockres_put(tmpres);
 769                         tmpres = NULL;
 770                         goto lookup;
 771                 }
 772
 773                 /* Wait on the thread that is mastering the resource */
 774                 if (tmpres->owner == DLM_LOCK_RES_OWNER_UNKNOWN) {
 775                         __dlm_wait_on_lockres(tmpres);
 776                         BUG_ON(tmpres->owner == DLM_LOCK_RES_OWNER_UNKNOWN);
 777                         spin_unlock(&tmpres->spinlock);
 778                         dlm_lockres_put(tmpres);
 779                         tmpres = NULL;
 780                         goto lookup;
 781                 }
 782
 783                 /* Wait on the resource purge to complete before continuing */
 784                 if (tmpres->state & DLM_LOCK_RES_DROPPING_REF) {
 785                         BUG_ON(tmpres->owner == dlm->node_num);
 786                         __dlm_wait_on_lockres_flags(tmpres,
 787                                                     DLM_LOCK_RES_DROPPING_REF);
 788                         spin_unlock(&tmpres->spinlock);
 789                         dlm_lockres_put(tmpres);
 790                         tmpres = NULL;
 791                         goto lookup;
 792                 }
 793
 794                 /* Grab inflight ref to pin the resource */
 795                 dlm_lockres_grab_inflight_ref(dlm, tmpres);
 796
 797                 spin_unlock(&tmpres->spinlock);
 798                 if (res)
 799                         dlm_lockres_put(res);
 800                 res = tmpres;
 801                 goto leave;
 802         }
 803
 804         if (!res) {
 805                 spin_unlock(&dlm->spinlock);
 806                 mlog(0, "allocating a new resource\n");
 807                 /* nothing found and we need to allocate one. */
 808                 alloc_mle = kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
 809                 if (!alloc_mle)
 810                         goto leave;
 811                 res = dlm_new_lockres(dlm, lockid, namelen);
 812                 if (!res)
 813                         goto leave;
 814                 goto lookup;
 815         }
 816
 817         mlog(0, "no lockres found, allocated our own: %p\n", res);
 818
 819         if (flags & LKM_LOCAL) {
 820                 /* caller knows it's safe to assume it's not mastered elsewhere
 821                  * DONE!  return right away */
 822                 spin_lock(&res->spinlock);
 823                 dlm_change_lockres_owner(dlm, res, dlm->node_num);
 824                 __dlm_insert_lockres(dlm, res);
 825                 dlm_lockres_grab_inflight_ref(dlm, res);
 826                 spin_unlock(&res->spinlock);
 827                 spin_unlock(&dlm->spinlock);
 828                 /* lockres still marked IN_PROGRESS */
 829                 goto wake_waiters;
 830         }
 831
 832         /* check master list to see if another node has started mastering it */
 833         spin_lock(&dlm->master_lock);
 834
 835         /* if we found a block, wait for lock to be mastered by another node */
 836         blocked = dlm_find_mle(dlm, &mle, (char *)lockid, namelen);
 837         if (blocked) {
 838                 int mig;
 839                 if (mle->type == DLM_MLE_MASTER) {
 840                         mlog(ML_ERROR, "master entry for nonexistent lock!\n");
 841                         BUG();
 842                 }
 843                 mig = (mle->type == DLM_MLE_MIGRATION);
 844                 /* if there is a migration in progress, let the migration
 845                  * finish before continuing.  we can wait for the absence
 846                  * of the MIGRATION mle: either the migrate finished or
 847                  * one of the nodes died and the mle was cleaned up.
 848                  * if there is a BLOCK here, but it already has a master
 849                  * set, we are too late.  the master does not have a ref
 850                  * for us in the refmap.  detach the mle and drop it.
 851                  * either way, go back to the top and start over. */
 852                 if (mig || mle->master != O2NM_MAX_NODES) {
 853                         BUG_ON(mig && mle->master == dlm->node_num);
 854                         /* we arrived too late.  the master does not
 855                          * have a ref for us. retry. */
 856                         mlog(0, "%s:%.*s: late on %s\n",
 857                              dlm->name, namelen, lockid,
 858                              mig ?  "MIGRATION" : "BLOCK");
 859                         spin_unlock(&dlm->master_lock);
 860                         spin_unlock(&dlm->spinlock);
 861
 862                         /* master is known, detach */
 863                         if (!mig)
 864                                 dlm_mle_detach_hb_events(dlm, mle);
 865                         dlm_put_mle(mle);
 866                         mle = NULL;
 867                         /* this is lame, but we can't wait on either
 868                          * the mle or lockres waitqueue here */
 869                         if (mig)
 870                                 msleep(100);
 871                         goto lookup;
 872                 }
 873         } else {
 874                 /* go ahead and try to master lock on this node */
 875                 mle = alloc_mle;
 876                 /* make sure this does not get freed below */
 877                 alloc_mle = NULL;
 878                 dlm_init_mle(mle, DLM_MLE_MASTER, dlm, res, NULL, 0);
 879                 set_bit(dlm->node_num, mle->maybe_map);
 880                 __dlm_insert_mle(dlm, mle);
 881
 882                 /* still holding the dlm spinlock, check the recovery map
 883                  * to see if there are any nodes that still need to be
 884                  * considered.  these will not appear in the mle nodemap
 885                  * but they might own this lockres.  wait on them. */
 886                 bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
 887                 if (bit < O2NM_MAX_NODES) {
 888                         mlog(0, "%s: res %.*s, At least one node (%d) "
 889                              "to recover before lock mastery can begin\n",
 890                              dlm->name, namelen, (char *)lockid, bit);
 891                         wait_on_recovery = 1;
 892                 }
 893         }
 894
 895         /* at this point there is either a DLM_MLE_BLOCK or a
 896          * DLM_MLE_MASTER on the master list, so it's safe to add the
 897          * lockres to the hashtable.  anyone who finds the lock will
 898          * still have to wait on the IN_PROGRESS. */
 899
 900         /* finally add the lockres to its hash bucket */
 901         __dlm_insert_lockres(dlm, res);
 902
 903         /* since this lockres is new it doesn't not require the spinlock */
 904         __dlm_lockres_grab_inflight_ref(dlm, res);
 905
 906         /* get an extra ref on the mle in case this is a BLOCK
 907          * if so, the creator of the BLOCK may try to put the last
 908          * ref at this time in the assert master handler, so we
 909          * need an extra one to keep from a bad ptr deref. */
 910         dlm_get_mle_inuse(mle);
 911         spin_unlock(&dlm->master_lock);
 912         spin_unlock(&dlm->spinlock);
 913
 914 redo_request:
 915         while (wait_on_recovery) {
 916                 /* any cluster changes that occurred after dropping the
 917                  * dlm spinlock would be detectable be a change on the mle,
 918                  * so we only need to clear out the recovery map once. */
 919                 if (dlm_is_recovery_lock(lockid, namelen)) {
 920                         mlog(0, "%s: Recovery map is not empty, but must "
 921                              "master $RECOVERY lock now\n", dlm->name);
 922                         if (!dlm_pre_master_reco_lockres(dlm, res))
 923                                 wait_on_recovery = 0;
 924                         else {
 925                                 mlog(0, "%s: waiting 500ms for heartbeat state "
 926                                     "change\n", dlm->name);
 927                                 msleep(500);
 928                         }
 929                         continue;
 930                 }
 931
 932                 dlm_kick_recovery_thread(dlm);
 933                 msleep(1000);
 934                 dlm_wait_for_recovery(dlm);
 935
 936                 spin_lock(&dlm->spinlock);
 937                 bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
 938                 if (bit < O2NM_MAX_NODES) {
 939                         mlog(0, "%s: res %.*s, At least one node (%d) "
 940                              "to recover before lock mastery can begin\n",
 941                              dlm->name, namelen, (char *)lockid, bit);
 942                         wait_on_recovery = 1;
 943                 } else
 944                         wait_on_recovery = 0;
 945                 spin_unlock(&dlm->spinlock);
 946
 947                 if (wait_on_recovery)
 948                         dlm_wait_for_node_recovery(dlm, bit, 10000);
 949         }
 950
 951         /* must wait for lock to be mastered elsewhere */
 952         if (blocked)
 953                 goto wait;
 954
 955         ret = -EINVAL;
 956         dlm_node_iter_init(mle->vote_map, &iter);
 957         while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
 958                 ret = dlm_do_master_request(res, mle, nodenum);
 959                 if (ret < 0)
 960                         mlog_errno(ret);
 961                 if (mle->master != O2NM_MAX_NODES) {
 962                         /* found a master ! */
 963                         if (mle->master <= nodenum)
 964                                 break;
 965                         /* if our master request has not reached the master
 966                          * yet, keep going until it does.  this is how the
 967                          * master will know that asserts are needed back to
 968                          * the lower nodes. */
 969                         mlog(0, "%s: res %.*s, Requests only up to %u but "
 970                              "master is %u, keep going\n", dlm->name, namelen,
 971                              lockid, nodenum, mle->master);
 972                 }
 973         }
 974
 975 wait:
 976         /* keep going until the response map includes all nodes */
 977         ret = dlm_wait_for_lock_mastery(dlm, res, mle, &blocked);
 978         if (ret < 0) {
 979                 wait_on_recovery = 1;
 980                 mlog(0, "%s: res %.*s, Node map changed, redo the master "
 981                      "request now, blocked=%d\n", dlm->name, res->lockname.len,
 982                      res->lockname.name, blocked);
 983                 if (++tries > 20) {
 984                         mlog(ML_ERROR, "%s: res %.*s, Spinning on "
 985                              "dlm_wait_for_lock_mastery, blocked = %d\n",
 986                              dlm->name, res->lockname.len,
 987                              res->lockname.name, blocked);
 988                         dlm_print_one_lock_resource(res);
 989                         dlm_print_one_mle(mle);
 990                         tries = 0;
 991                 }
 992                 goto redo_request;
 993         }
 994
 995         mlog(0, "%s: res %.*s, Mastered by %u\n", dlm->name, res->lockname.len,
 996              res->lockname.name, res->owner);
 997         /* make sure we never continue without this */
 998         BUG_ON(res->owner == O2NM_MAX_NODES);
 999
1000         /* master is known, detach if not already detached */
1001         dlm_mle_detach_hb_events(dlm, mle);
1002         dlm_put_mle(mle);
1003         /* put the extra ref */
1004         dlm_put_mle_inuse(mle);
1005
1006 wake_waiters:
1007         spin_lock(&res->spinlock);
1008         res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
1009         spin_unlock(&res->spinlock);
1010         wake_up(&res->wq);
1011
1012 leave:
1013         /* need to free the unused mle */
1014         if (alloc_mle)
1015                 kmem_cache_free(dlm_mle_cache, alloc_mle);
1016
1017         return res;
1018 }
1019
1020
1021 #define DLM_MASTERY_TIMEOUT_MS   5000
1022
1023 static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
1024                                      struct dlm_lock_resource *res,
1025                                      struct dlm_master_list_entry *mle,
1026                                      int *blocked)
1027 {
1028         u8 m;
1029         int ret, bit;
1030         int map_changed, voting_done;
1031         int assert, sleep;
1032
1033 recheck:
1034         ret = 0;
1035         assert = 0;
1036
1037         /* check if another node has already become the owner */
1038         spin_lock(&res->spinlock);
1039         if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1040                 mlog(0, "%s:%.*s: owner is suddenly %u\n", dlm->name,
1041                      res->lockname.len, res->lockname.name, res->owner);
1042                 spin_unlock(&res->spinlock);
1043                 /* this will cause the master to re-assert across
1044                  * the whole cluster, freeing up mles */
1045                 if (res->owner != dlm->node_num) {
1046                         ret = dlm_do_master_request(res, mle, res->owner);
1047                         if (ret < 0) {
1048                                 /* give recovery a chance to run */
1049                                 mlog(ML_ERROR, "link to %u went down?: %d\n", res->owner, ret);
1050                                 msleep(500);
1051                                 goto recheck;
1052                         }
1053                 }
1054                 ret = 0;
1055                 goto leave;
1056         }
1057         spin_unlock(&res->spinlock);
1058
1059         spin_lock(&mle->spinlock);
1060         m = mle->master;
1061         map_changed = (memcmp(mle->vote_map, mle->node_map,
1062                               sizeof(mle->vote_map)) != 0);
1063         voting_done = (memcmp(mle->vote_map, mle->response_map,
1064                              sizeof(mle->vote_map)) == 0);
1065
1066         /* restart if we hit any errors */
1067         if (map_changed) {
1068                 int b;
1069                 mlog(0, "%s: %.*s: node map changed, restarting\n",
1070                      dlm->name, res->lockname.len, res->lockname.name);
1071                 ret = dlm_restart_lock_mastery(dlm, res, mle, *blocked);
1072                 b = (mle->type == DLM_MLE_BLOCK);
1073                 if ((*blocked && !b) || (!*blocked && b)) {
1074                         mlog(0, "%s:%.*s: status change: old=%d new=%d\n",
1075                              dlm->name, res->lockname.len, res->lockname.name,
1076                              *blocked, b);
1077                         *blocked = b;
1078                 }
1079                 spin_unlock(&mle->spinlock);
1080                 if (ret < 0) {
1081                         mlog_errno(ret);
1082                         goto leave;
1083                 }
1084                 mlog(0, "%s:%.*s: restart lock mastery succeeded, "
1085                      "rechecking now\n", dlm->name, res->lockname.len,
1086                      res->lockname.name);
1087                 goto recheck;
1088         } else {
1089                 if (!voting_done) {
1090                         mlog(0, "map not changed and voting not done "
1091                              "for %s:%.*s\n", dlm->name, res->lockname.len,
1092                              res->lockname.name);
1093                 }
1094         }
1095
1096         if (m != O2NM_MAX_NODES) {
1097                 /* another node has done an assert!
1098                  * all done! */
1099                 sleep = 0;
1100         } else {
1101                 sleep = 1;
1102                 /* have all nodes responded? */
1103                 if (voting_done && !*blocked) {
1104                         bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
1105                         if (dlm->node_num <= bit) {
1106                                 /* my node number is lowest.
1107                                  * now tell other nodes that I am
1108                                  * mastering this. */
1109                                 mle->master = dlm->node_num;
1110                                 /* ref was grabbed in get_lock_resource
1111                                  * will be dropped in dlmlock_master */
1112                                 assert = 1;
1113                                 sleep = 0;
1114                         }
1115                         /* if voting is done, but we have not received
1116                          * an assert master yet, we must sleep */
1117                 }
1118         }
1119
1120         spin_unlock(&mle->spinlock);
1121
1122         /* sleep if we haven't finished voting yet */
1123         if (sleep) {
1124                 unsigned long timeo = msecs_to_jiffies(DLM_MASTERY_TIMEOUT_MS);
1125
1126                 /*
1127                 if (atomic_read(&mle->mle_refs.refcount) < 2)
1128                         mlog(ML_ERROR, "mle (%p) refs=%d, name=%.*s\n", mle,
1129                         atomic_read(&mle->mle_refs.refcount),
1130                         res->lockname.len, res->lockname.name);
1131                 */
1132                 atomic_set(&mle->woken, 0);
1133                 (void)wait_event_timeout(mle->wq,
1134                                          (atomic_read(&mle->woken) == 1),
1135                                          timeo);
1136                 if (res->owner == O2NM_MAX_NODES) {
1137                         mlog(0, "%s:%.*s: waiting again\n", dlm->name,
1138                              res->lockname.len, res->lockname.name);
1139                         goto recheck;
1140                 }
1141                 mlog(0, "done waiting, master is %u\n", res->owner);
1142                 ret = 0;
1143                 goto leave;
1144         }
1145
1146         ret = 0;   /* done */
1147         if (assert) {
1148                 m = dlm->node_num;
1149                 mlog(0, "about to master %.*s here, this=%u\n",
1150                      res->lockname.len, res->lockname.name, m);
1151                 ret = dlm_do_assert_master(dlm, res, mle->vote_map, 0);
1152                 if (ret) {
1153                         /* This is a failure in the network path,
1154                          * not in the response to the assert_master
1155                          * (any nonzero response is a BUG on this node).
1156                          * Most likely a socket just got disconnected
1157                          * due to node death. */
1158                         mlog_errno(ret);
1159                 }
1160                 /* no longer need to restart lock mastery.
1161                  * all living nodes have been contacted. */
1162                 ret = 0;
1163         }
1164
1165         /* set the lockres owner */
1166         spin_lock(&res->spinlock);
1167         /* mastery reference obtained either during
1168          * assert_master_handler or in get_lock_resource */
1169         dlm_change_lockres_owner(dlm, res, m);
1170         spin_unlock(&res->spinlock);
1171
1172 leave:
1173         return ret;
1174 }
1175
1176 struct dlm_bitmap_diff_iter
1177 {
1178         int curnode;
1179         unsigned long *orig_bm;
1180         unsigned long *cur_bm;
1181         unsigned long diff_bm[BITS_TO_LONGS(O2NM_MAX_NODES)];
1182 };
1183
1184 enum dlm_node_state_change
1185 {
1186         NODE_DOWN = -1,
1187         NODE_NO_CHANGE = 0,
1188         NODE_UP
1189 };
1190
1191 static void dlm_bitmap_diff_iter_init(struct dlm_bitmap_diff_iter *iter,
1192                                       unsigned long *orig_bm,
1193                                       unsigned long *cur_bm)
1194 {
1195         unsigned long p1, p2;
1196         int i;
1197
1198         iter->curnode = -1;
1199         iter->orig_bm = orig_bm;
1200         iter->cur_bm = cur_bm;
1201
1202         for (i = 0; i < BITS_TO_LONGS(O2NM_MAX_NODES); i++) {
1203                 p1 = *(iter->orig_bm + i);
1204                 p2 = *(iter->cur_bm + i);
1205                 iter->diff_bm[i] = (p1 & ~p2) | (p2 & ~p1);
1206         }
1207 }
1208
1209 static int dlm_bitmap_diff_iter_next(struct dlm_bitmap_diff_iter *iter,
1210                                      enum dlm_node_state_change *state)
1211 {
1212         int bit;
1213
1214         if (iter->curnode >= O2NM_MAX_NODES)
1215                 return -ENOENT;
1216
1217         bit = find_next_bit(iter->diff_bm, O2NM_MAX_NODES,
1218                             iter->curnode+1);
1219         if (bit >= O2NM_MAX_NODES) {
1220                 iter->curnode = O2NM_MAX_NODES;
1221                 return -ENOENT;
1222         }
1223
1224         /* if it was there in the original then this node died */
1225         if (test_bit(bit, iter->orig_bm))
1226                 *state = NODE_DOWN;
1227         else
1228                 *state = NODE_UP;
1229
1230         iter->curnode = bit;
1231         return bit;
1232 }
1233
1234
1235 static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
1236                                     struct dlm_lock_resource *res,
1237                                     struct dlm_master_list_entry *mle,
1238                                     int blocked)
1239 {
1240         struct dlm_bitmap_diff_iter bdi;
1241         enum dlm_node_state_change sc;
1242         int node;
1243         int ret = 0;
1244
1245         mlog(0, "something happened such that the "
1246              "master process may need to be restarted!\n");
1247
1248         assert_spin_locked(&mle->spinlock);
1249
1250         dlm_bitmap_diff_iter_init(&bdi, mle->vote_map, mle->node_map);
1251         node = dlm_bitmap_diff_iter_next(&bdi, &sc);
1252         while (node >= 0) {
1253                 if (sc == NODE_UP) {
1254                         /* a node came up.  clear any old vote from
1255                          * the response map and set it in the vote map
1256                          * then restart the mastery. */
1257                         mlog(ML_NOTICE, "node %d up while restarting\n", node);
1258
1259                         /* redo the master request, but only for the new node */
1260                         mlog(0, "sending request to new node\n");
1261                         clear_bit(node, mle->response_map);
1262                         set_bit(node, mle->vote_map);
1263                 } else {
1264                         mlog(ML_ERROR, "node down! %d\n", node);
1265                         if (blocked) {
1266                                 int lowest = find_next_bit(mle->maybe_map,
1267                                                        O2NM_MAX_NODES, 0);
1268
1269                                 /* act like it was never there */
1270                                 clear_bit(node, mle->maybe_map);
1271
1272                                 if (node == lowest) {
1273                                         mlog(0, "expected master %u died"
1274                                             " while this node was blocked "
1275                                             "waiting on it!\n", node);
1276                                         lowest = find_next_bit(mle->maybe_map,
1277                                                         O2NM_MAX_NODES,
1278                                                         lowest+1);
1279                                         if (lowest < O2NM_MAX_NODES) {
1280                                                 mlog(0, "%s:%.*s:still "
1281                                                      "blocked. waiting on %u "
1282                                                      "now\n", dlm->name,
1283                                                      res->lockname.len,
1284                                                      res->lockname.name,
1285                                                      lowest);
1286                                         } else {
1287                                                 /* mle is an MLE_BLOCK, but
1288                                                  * there is now nothing left to
1289                                                  * block on.  we need to return
1290                                                  * all the way back out and try
1291                                                  * again with an MLE_MASTER.
1292                                                  * dlm_do_local_recovery_cleanup
1293                                                  * has already run, so the mle
1294                                                  * refcount is ok */
1295                                                 mlog(0, "%s:%.*s: no "
1296                                                      "longer blocking. try to "
1297                                                      "master this here\n",
1298                                                      dlm->name,
1299                                                      res->lockname.len,
1300                                                      res->lockname.name);
1301                                                 mle->type = DLM_MLE_MASTER;
1302                                                 mle->mleres = res;
1303                                         }
1304                                 }
1305                         }
1306
1307                         /* now blank out everything, as if we had never
1308                          * contacted anyone */
1309                         memset(mle->maybe_map, 0, sizeof(mle->maybe_map));
1310                         memset(mle->response_map, 0, sizeof(mle->response_map));
1311                         /* reset the vote_map to the current node_map */
1312                         memcpy(mle->vote_map, mle->node_map,
1313                                sizeof(mle->node_map));
1314                         /* put myself into the maybe map */
1315                         if (mle->type != DLM_MLE_BLOCK)
1316                                 set_bit(dlm->node_num, mle->maybe_map);
1317                 }
1318                 ret = -EAGAIN;
1319                 node = dlm_bitmap_diff_iter_next(&bdi, &sc);
1320         }
1321         return ret;
1322 }
1323
1324
1325 /*
1326  * DLM_MASTER_REQUEST_MSG
1327  *
1328  * returns: 0 on success,
1329  *          -errno on a network error
1330  *
1331  * on error, the caller should assume the target node is "dead"
1332  *
1333  */
1334
1335 static int dlm_do_master_request(struct dlm_lock_resource *res,
1336                                  struct dlm_master_list_entry *mle, int to)
1337 {
1338         struct dlm_ctxt *dlm = mle->dlm;
1339         struct dlm_master_request request;
1340         int ret, response=0, resend;
1341
1342         memset(&request, 0, sizeof(request));
1343         request.node_idx = dlm->node_num;
1344
1345         BUG_ON(mle->type == DLM_MLE_MIGRATION);
1346
1347         request.namelen = (u8)mle->mnamelen;
1348         memcpy(request.name, mle->mname, request.namelen);
1349
1350 again:
1351         ret = o2net_send_message(DLM_MASTER_REQUEST_MSG, dlm->key, &request,
1352                                  sizeof(request), to, &response);
1353         if (ret < 0)  {
1354                 if (ret == -ESRCH) {
1355                         /* should never happen */
1356                         mlog(ML_ERROR, "TCP stack not ready!\n");
1357                         BUG();
1358                 } else if (ret == -EINVAL) {
1359                         mlog(ML_ERROR, "bad args passed to o2net!\n");
1360                         BUG();
1361                 } else if (ret == -ENOMEM) {
1362                         mlog(ML_ERROR, "out of memory while trying to send "
1363                              "network message!  retrying\n");
1364                         /* this is totally crude */
1365                         msleep(50);
1366                         goto again;
1367                 } else if (!dlm_is_host_down(ret)) {
1368                         /* not a network error. bad. */
1369                         mlog_errno(ret);
1370                         mlog(ML_ERROR, "unhandled error!");
1371                         BUG();
1372                 }
1373                 /* all other errors should be network errors,
1374                  * and likely indicate node death */
1375                 mlog(ML_ERROR, "link to %d went down!\n", to);
1376                 goto out;
1377         }
1378
1379         ret = 0;
1380         resend = 0;
1381         spin_lock(&mle->spinlock);
1382         switch (response) {
1383                 case DLM_MASTER_RESP_YES:
1384                         set_bit(to, mle->response_map);
1385                         mlog(0, "node %u is the master, response=YES\n", to);
1386                         mlog(0, "%s:%.*s: master node %u now knows I have a "
1387                              "reference\n", dlm->name, res->lockname.len,
1388                              res->lockname.name, to);
1389                         mle->master = to;
1390                         break;
1391                 case DLM_MASTER_RESP_NO:
1392                         mlog(0, "node %u not master, response=NO\n", to);
1393                         set_bit(to, mle->response_map);
1394                         break;
1395                 case DLM_MASTER_RESP_MAYBE:
1396                         mlog(0, "node %u not master, response=MAYBE\n", to);
1397                         set_bit(to, mle->response_map);
1398                         set_bit(to, mle->maybe_map);
1399                         break;
1400                 case DLM_MASTER_RESP_ERROR:
1401                         mlog(0, "node %u hit an error, resending\n", to);
1402                         resend = 1;
1403                         response = 0;
1404                         break;
1405                 default:
1406                         mlog(ML_ERROR, "bad response! %u\n", response);
1407                         BUG();
1408         }
1409         spin_unlock(&mle->spinlock);
1410         if (resend) {
1411                 /* this is also totally crude */
1412                 msleep(50);
1413                 goto again;
1414         }
1415
1416 out:
1417         return ret;
1418 }
1419
1420 /*
1421  * locks that can be taken here:
1422  * dlm->spinlock
1423  * res->spinlock
1424  * mle->spinlock
1425  * dlm->master_list
1426  *
1427  * if possible, TRIM THIS DOWN!!!
1428  */
1429 int dlm_master_request_handler(struct o2net_msg *msg, u32 len, void *data,
1430                                void **ret_data)
1431 {
1432         u8 response = DLM_MASTER_RESP_MAYBE;
1433         struct dlm_ctxt *dlm = data;
1434         struct dlm_lock_resource *res = NULL;
1435         struct dlm_master_request *request = (struct dlm_master_request *) msg->buf;
1436         struct dlm_master_list_entry *mle = NULL, *tmpmle = NULL;
1437         char *name;
1438         unsigned int namelen, hash;
1439         int found, ret;
1440         int set_maybe;
1441         int dispatch_assert = 0;
1442
1443         if (!dlm_grab(dlm))
1444                 return DLM_MASTER_RESP_NO;
1445
1446         if (!dlm_domain_fully_joined(dlm)) {
1447                 response = DLM_MASTER_RESP_NO;
1448                 goto send_response;
1449         }
1450
1451         name = request->name;
1452         namelen = request->namelen;
1453         hash = dlm_lockid_hash(name, namelen);
1454
1455         if (namelen > DLM_LOCKID_NAME_MAX) {
1456                 response = DLM_IVBUFLEN;
1457                 goto send_response;
1458         }
1459
1460 way_up_top:
1461         spin_lock(&dlm->spinlock);
1462         res = __dlm_lookup_lockres(dlm, name, namelen, hash);
1463         if (res) {
1464                 spin_unlock(&dlm->spinlock);
1465
1466                 /* take care of the easy cases up front */
1467                 spin_lock(&res->spinlock);
1468
1469                 /*
1470                  * Right after dlm spinlock was released, dlm_thread could have
1471                  * purged the lockres. Check if lockres got unhashed. If so
1472                  * start over.
1473                  */
1474                 if (hlist_unhashed(&res->hash_node)) {
1475                         spin_unlock(&res->spinlock);
1476                         dlm_lockres_put(res);
1477                         goto way_up_top;
1478                 }
1479
1480                 if (res->state & (DLM_LOCK_RES_RECOVERING|
1481                                   DLM_LOCK_RES_MIGRATING)) {
1482                         spin_unlock(&res->spinlock);
1483                         mlog(0, "returning DLM_MASTER_RESP_ERROR since res is "
1484                              "being recovered/migrated\n");
1485                         response = DLM_MASTER_RESP_ERROR;
1486                         if (mle)
1487                                 kmem_cache_free(dlm_mle_cache, mle);
1488                         goto send_response;
1489                 }
1490
1491                 if (res->owner == dlm->node_num) {
1492                         dlm_lockres_set_refmap_bit(dlm, res, request->node_idx);
1493                         spin_unlock(&res->spinlock);
1494                         response = DLM_MASTER_RESP_YES;
1495                         if (mle)
1496                                 kmem_cache_free(dlm_mle_cache, mle);
1497
1498                         /* this node is the owner.
1499                          * there is some extra work that needs to
1500                          * happen now.  the requesting node has
1501                          * caused all nodes up to this one to
1502                          * create mles.  this node now needs to
1503                          * go back and clean those up. */
1504                         dispatch_assert = 1;
1505                         goto send_response;
1506                 } else if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1507                         spin_unlock(&res->spinlock);
1508                         // mlog(0, "node %u is the master\n", res->owner);
1509                         response = DLM_MASTER_RESP_NO;
1510                         if (mle)
1511                                 kmem_cache_free(dlm_mle_cache, mle);
1512                         goto send_response;
1513                 }
1514
1515                 /* ok, there is no owner.  either this node is
1516                  * being blocked, or it is actively trying to
1517                  * master this lock. */
1518                 if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
1519                         mlog(ML_ERROR, "lock with no owner should be "
1520                              "in-progress!\n");
1521                         BUG();
1522                 }
1523
1524                 // mlog(0, "lockres is in progress...\n");
1525                 spin_lock(&dlm->master_lock);
1526                 found = dlm_find_mle(dlm, &tmpmle, name, namelen);
1527                 if (!found) {
1528                         mlog(ML_ERROR, "no mle found for this lock!\n");
1529                         BUG();
1530                 }
1531                 set_maybe = 1;
1532                 spin_lock(&tmpmle->spinlock);
1533                 if (tmpmle->type == DLM_MLE_BLOCK) {
1534                         // mlog(0, "this node is waiting for "
1535                         // "lockres to be mastered\n");
1536                         response = DLM_MASTER_RESP_NO;
1537                 } else if (tmpmle->type == DLM_MLE_MIGRATION) {
1538                         mlog(0, "node %u is master, but trying to migrate to "
1539                              "node %u.\n", tmpmle->master, tmpmle->new_master);
1540                         if (tmpmle->master == dlm->node_num) {
1541                                 mlog(ML_ERROR, "no owner on lockres, but this "
1542                                      "node is trying to migrate it to %u?!\n",
1543                                      tmpmle->new_master);
1544                                 BUG();
1545                         } else {
1546                                 /* the real master can respond on its own */
1547                                 response = DLM_MASTER_RESP_NO;
1548                         }
1549                 } else if (tmpmle->master != DLM_LOCK_RES_OWNER_UNKNOWN) {
1550                         set_maybe = 0;
1551                         if (tmpmle->master == dlm->node_num) {
1552                                 response = DLM_MASTER_RESP_YES;
1553                                 /* this node will be the owner.
1554                                  * go back and clean the mles on any
1555                                  * other nodes */
1556                                 dispatch_assert = 1;
1557                                 dlm_lockres_set_refmap_bit(dlm, res,
1558                                                            request->node_idx);
1559                         } else
1560                                 response = DLM_MASTER_RESP_NO;
1561                 } else {
1562                         // mlog(0, "this node is attempting to "
1563                         // "master lockres\n");
1564                         response = DLM_MASTER_RESP_MAYBE;
1565                 }
1566                 if (set_maybe)
1567                         set_bit(request->node_idx, tmpmle->maybe_map);
1568                 spin_unlock(&tmpmle->spinlock);
1569
1570                 spin_unlock(&dlm->master_lock);
1571                 spin_unlock(&res->spinlock);
1572
1573                 /* keep the mle attached to heartbeat events */
1574                 dlm_put_mle(tmpmle);
1575                 if (mle)
1576                         kmem_cache_free(dlm_mle_cache, mle);
1577                 goto send_response;
1578         }
1579
1580         /*
1581          * lockres doesn't exist on this node
1582          * if there is an MLE_BLOCK, return NO
1583          * if there is an MLE_MASTER, return MAYBE
1584          * otherwise, add an MLE_BLOCK, return NO
1585          */
1586         spin_lock(&dlm->master_lock);
1587         found = dlm_find_mle(dlm, &tmpmle, name, namelen);
1588         if (!found) {
1589                 /* this lockid has never been seen on this node yet */
1590                 // mlog(0, "no mle found\n");
1591                 if (!mle) {
1592                         spin_unlock(&dlm->master_lock);
1593                         spin_unlock(&dlm->spinlock);
1594
1595                         mle = kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
1596                         if (!mle) {
1597                                 response = DLM_MASTER_RESP_ERROR;
1598                                 mlog_errno(-ENOMEM);
1599                                 goto send_response;
1600                         }
1601                         goto way_up_top;
1602                 }
1603
1604                 // mlog(0, "this is second time thru, already allocated, "
1605                 // "add the block.\n");
1606                 dlm_init_mle(mle, DLM_MLE_BLOCK, dlm, NULL, name, namelen);
1607                 set_bit(request->node_idx, mle->maybe_map);
1608                 __dlm_insert_mle(dlm, mle);
1609                 response = DLM_MASTER_RESP_NO;
1610         } else {
1611                 // mlog(0, "mle was found\n");
1612                 set_maybe = 1;
1613                 spin_lock(&tmpmle->spinlock);
1614                 if (tmpmle->master == dlm->node_num) {
1615                         mlog(ML_ERROR, "no lockres, but an mle with this node as master!\n");
1616                         BUG();
1617                 }
1618                 if (tmpmle->type == DLM_MLE_BLOCK)
1619                         response = DLM_MASTER_RESP_NO;
1620                 else if (tmpmle->type == DLM_MLE_MIGRATION) {
1621                         mlog(0, "migration mle was found (%u->%u)\n",
1622                              tmpmle->master, tmpmle->new_master);
1623                         /* real master can respond on its own */
1624                         response = DLM_MASTER_RESP_NO;
1625                 } else
1626                         response = DLM_MASTER_RESP_MAYBE;
1627                 if (set_maybe)
1628                         set_bit(request->node_idx, tmpmle->maybe_map);
1629                 spin_unlock(&tmpmle->spinlock);
1630         }
1631         spin_unlock(&dlm->master_lock);
1632         spin_unlock(&dlm->spinlock);
1633
1634         if (found) {
1635                 /* keep the mle attached to heartbeat events */
1636                 dlm_put_mle(tmpmle);
1637         }
1638 send_response:
1639         /*
1640          * __dlm_lookup_lockres() grabbed a reference to this lockres.
1641          * The reference is released by dlm_assert_master_worker() under
1642          * the call to dlm_dispatch_assert_master().  If
1643          * dlm_assert_master_worker() isn't called, we drop it here.
1644          */
1645         if (dispatch_assert) {
1646                 if (response != DLM_MASTER_RESP_YES)
1647                         mlog(ML_ERROR, "invalid response %d\n", response);
1648                 if (!res) {
1649                         mlog(ML_ERROR, "bad lockres while trying to assert!\n");
1650                         BUG();
1651                 }
1652                 mlog(0, "%u is the owner of %.*s, cleaning everyone else\n",
1653                              dlm->node_num, res->lockname.len, res->lockname.name);
1654                 spin_lock(&res->spinlock);
1655                 ret = dlm_dispatch_assert_master(dlm, res, 0, request->node_idx,
1656                                                  DLM_ASSERT_MASTER_MLE_CLEANUP);
1657                 if (ret < 0) {
1658                         mlog(ML_ERROR, "failed to dispatch assert master work\n");
1659                         response = DLM_MASTER_RESP_ERROR;
1660                         dlm_lockres_put(res);
1661                 } else
1662                         __dlm_lockres_grab_inflight_worker(dlm, res);
1663                 spin_unlock(&res->spinlock);
1664         } else {
1665                 if (res)
1666                         dlm_lockres_put(res);
1667         }
1668
1669         dlm_put(dlm);
1670         return response;
1671 }
1672
1673 /*
1674  * DLM_ASSERT_MASTER_MSG
1675  */
1676
1677
1678 /*
1679  * NOTE: this can be used for debugging
1680  * can periodically run all locks owned by this node
1681  * and re-assert across the cluster...
1682  */
1683 static int dlm_do_assert_master(struct dlm_ctxt *dlm,
1684                                 struct dlm_lock_resource *res,
1685                                 void *nodemap, u32 flags)
1686 {
1687         struct dlm_assert_master assert;
1688         int to, tmpret;
1689         struct dlm_node_iter iter;
1690         int ret = 0;
1691         int reassert;
1692         const char *lockname = res->lockname.name;
1693         unsigned int namelen = res->lockname.len;
1694
1695         BUG_ON(namelen > O2NM_MAX_NAME_LEN);
1696
1697         spin_lock(&res->spinlock);
1698         res->state |= DLM_LOCK_RES_SETREF_INPROG;
1699         spin_unlock(&res->spinlock);
1700
1701 again:
1702         reassert = 0;
1703
1704         /* note that if this nodemap is empty, it returns 0 */
1705         dlm_node_iter_init(nodemap, &iter);
1706         while ((to = dlm_node_iter_next(&iter)) >= 0) {
1707                 int r = 0;
1708                 struct dlm_master_list_entry *mle = NULL;
1709
1710                 mlog(0, "sending assert master to %d (%.*s)\n", to,
1711                      namelen, lockname);
1712                 memset(&assert, 0, sizeof(assert));
1713                 assert.node_idx = dlm->node_num;
1714                 assert.namelen = namelen;
1715                 memcpy(assert.name, lockname, namelen);
1716                 assert.flags = cpu_to_be32(flags);
1717
1718                 tmpret = o2net_send_message(DLM_ASSERT_MASTER_MSG, dlm->key,
1719                                             &assert, sizeof(assert), to, &r);
1720                 if (tmpret < 0) {
1721                         mlog(ML_ERROR, "Error %d when sending message %u (key "
1722                              "0x%x) to node %u\n", tmpret,
1723                              DLM_ASSERT_MASTER_MSG, dlm->key, to);
1724                         if (!dlm_is_host_down(tmpret)) {
1725                                 mlog(ML_ERROR, "unhandled error=%d!\n", tmpret);
1726                                 BUG();
1727                         }
1728                         /* a node died.  finish out the rest of the nodes. */
1729                         mlog(0, "link to %d went down!\n", to);
1730                         /* any nonzero status return will do */
1731                         ret = tmpret;
1732                         r = 0;
1733                 } else if (r < 0) {
1734                         /* ok, something horribly messed.  kill thyself. */
1735                         mlog(ML_ERROR,"during assert master of %.*s to %u, "
1736                              "got %d.\n", namelen, lockname, to, r);
1737                         spin_lock(&dlm->spinlock);
1738                         spin_lock(&dlm->master_lock);
1739                         if (dlm_find_mle(dlm, &mle, (char *)lockname,
1740                                          namelen)) {
1741                                 dlm_print_one_mle(mle);
1742                                 __dlm_put_mle(mle);
1743                         }
1744                         spin_unlock(&dlm->master_lock);
1745                         spin_unlock(&dlm->spinlock);
1746                         BUG();
1747                 }
1748
1749                 if (r & DLM_ASSERT_RESPONSE_REASSERT &&
1750                     !(r & DLM_ASSERT_RESPONSE_MASTERY_REF)) {
1751                                 mlog(ML_ERROR, "%.*s: very strange, "
1752                                      "master MLE but no lockres on %u\n",
1753                                      namelen, lockname, to);
1754                 }
1755
1756                 if (r & DLM_ASSERT_RESPONSE_REASSERT) {
1757                         mlog(0, "%.*s: node %u create mles on other "
1758                              "nodes and requests a re-assert\n",
1759                              namelen, lockname, to);
1760                         reassert = 1;
1761                 }
1762                 if (r & DLM_ASSERT_RESPONSE_MASTERY_REF) {
1763                         mlog(0, "%.*s: node %u has a reference to this "
1764                              "lockres, set the bit in the refmap\n",
1765                              namelen, lockname, to);
1766                         spin_lock(&res->spinlock);
1767                         dlm_lockres_set_refmap_bit(dlm, res, to);
1768                         spin_unlock(&res->spinlock);
1769                 }
1770         }
1771
1772         if (reassert)
1773                 goto again;
1774
1775         spin_lock(&res->spinlock);
1776         res->state &= ~DLM_LOCK_RES_SETREF_INPROG;
1777         spin_unlock(&res->spinlock);
1778         wake_up(&res->wq);
1779
1780         return ret;
1781 }
1782
1783 /*
1784  * locks that can be taken here:
1785  * dlm->spinlock
1786  * res->spinlock
1787  * mle->spinlock
1788  * dlm->master_list
1789  *
1790  * if possible, TRIM THIS DOWN!!!
1791  */
1792 int dlm_assert_master_handler(struct o2net_msg *msg, u32 len, void *data,
1793                               void **ret_data)
1794 {
1795         struct dlm_ctxt *dlm = data;
1796         struct dlm_master_list_entry *mle = NULL;
1797         struct dlm_assert_master *assert = (struct dlm_assert_master *)msg->buf;
1798         struct dlm_lock_resource *res = NULL;
1799         char *name;
1800         unsigned int namelen, hash;
1801         u32 flags;
1802         int master_request = 0, have_lockres_ref = 0;
1803         int ret = 0;
1804
1805         if (!dlm_grab(dlm))
1806                 return 0;
1807
1808         name = assert->name;
1809         namelen = assert->namelen;
1810         hash = dlm_lockid_hash(name, namelen);
1811         flags = be32_to_cpu(assert->flags);
1812
1813         if (namelen > DLM_LOCKID_NAME_MAX) {
1814                 mlog(ML_ERROR, "Invalid name length!");
1815                 goto done;
1816         }
1817
1818         spin_lock(&dlm->spinlock);
1819
1820         if (flags)
1821                 mlog(0, "assert_master with flags: %u\n", flags);
1822
1823         /* find the MLE */
1824         spin_lock(&dlm->master_lock);
1825         if (!dlm_find_mle(dlm, &mle, name, namelen)) {
1826                 /* not an error, could be master just re-asserting */
1827                 mlog(0, "just got an assert_master from %u, but no "
1828                      "MLE for it! (%.*s)\n", assert->node_idx,
1829                      namelen, name);
1830         } else {
1831                 int bit = find_next_bit (mle->maybe_map, O2NM_MAX_NODES, 0);
1832                 if (bit >= O2NM_MAX_NODES) {
1833                         /* not necessarily an error, though less likely.
1834                          * could be master just re-asserting. */
1835                         mlog(0, "no bits set in the maybe_map, but %u "
1836                              "is asserting! (%.*s)\n", assert->node_idx,
1837                              namelen, name);
1838                 } else if (bit != assert->node_idx) {
1839                         if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
1840                                 mlog(0, "master %u was found, %u should "
1841                                      "back off\n", assert->node_idx, bit);
1842                         } else {
1843                                 /* with the fix for bug 569, a higher node
1844                                  * number winning the mastery will respond
1845                                  * YES to mastery requests, but this node
1846                                  * had no way of knowing.  let it pass. */
1847                                 mlog(0, "%u is the lowest node, "
1848                                      "%u is asserting. (%.*s)  %u must "
1849                                      "have begun after %u won.\n", bit,
1850                                      assert->node_idx, namelen, name, bit,
1851                                      assert->node_idx);
1852                         }
1853                 }
1854                 if (mle->type == DLM_MLE_MIGRATION) {
1855                         if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
1856                                 mlog(0, "%s:%.*s: got cleanup assert"
1857                                      " from %u for migration\n",
1858                                      dlm->name, namelen, name,
1859                                      assert->node_idx);
1860                         } else if (!(flags & DLM_ASSERT_MASTER_FINISH_MIGRATION)) {
1861                                 mlog(0, "%s:%.*s: got unrelated assert"
1862                                      " from %u for migration, ignoring\n",
1863                                      dlm->name, namelen, name,
1864                                      assert->node_idx);
1865                                 __dlm_put_mle(mle);
1866                                 spin_unlock(&dlm->master_lock);
1867                                 spin_unlock(&dlm->spinlock);
1868                                 goto done;
1869                         }
1870                 }
1871         }
1872         spin_unlock(&dlm->master_lock);
1873
1874         /* ok everything checks out with the MLE
1875          * now check to see if there is a lockres */
1876         res = __dlm_lookup_lockres(dlm, name, namelen, hash);
1877         if (res) {
1878                 spin_lock(&res->spinlock);
1879                 if (res->state & DLM_LOCK_RES_RECOVERING)  {
1880                         mlog(ML_ERROR, "%u asserting but %.*s is "
1881                              "RECOVERING!\n", assert->node_idx, namelen, name);
1882                         goto kill;
1883                 }
1884                 if (!mle) {
1885                         if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN &&
1886                             res->owner != assert->node_idx) {
1887                                 mlog(ML_ERROR, "DIE! Mastery assert from %u, "
1888                                      "but current owner is %u! (%.*s)\n",
1889                                      assert->node_idx, res->owner, namelen,
1890                                      name);
1891                                 __dlm_print_one_lock_resource(res);
1892                                 BUG();
1893                         }
1894                 } else if (mle->type != DLM_MLE_MIGRATION) {
1895                         if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1896                                 /* owner is just re-asserting */
1897                                 if (res->owner == assert->node_idx) {
1898                                         mlog(0, "owner %u re-asserting on "
1899                                              "lock %.*s\n", assert->node_idx,
1900                                              namelen, name);
1901                                         goto ok;
1902                                 }
1903                                 mlog(ML_ERROR, "got assert_master from "
1904                                      "node %u, but %u is the owner! "
1905                                      "(%.*s)\n", assert->node_idx,
1906                                      res->owner, namelen, name);
1907                                 goto kill;
1908                         }
1909                         if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
1910                                 mlog(ML_ERROR, "got assert from %u, but lock "
1911                                      "with no owner should be "
1912                                      "in-progress! (%.*s)\n",
1913                                      assert->node_idx,
1914                                      namelen, name);
1915                                 goto kill;
1916                         }
1917                 } else /* mle->type == DLM_MLE_MIGRATION */ {
1918                         /* should only be getting an assert from new master */
1919                         if (assert->node_idx != mle->new_master) {
1920                                 mlog(ML_ERROR, "got assert from %u, but "
1921                                      "new master is %u, and old master "
1922                                      "was %u (%.*s)\n",
1923                                      assert->node_idx, mle->new_master,
1924                                      mle->master, namelen, name);
1925                                 goto kill;
1926                         }
1927
1928                 }
1929 ok:
1930                 spin_unlock(&res->spinlock);
1931         }
1932
1933         // mlog(0, "woo!  got an assert_master from node %u!\n",
1934         //           assert->node_idx);
1935         if (mle) {
1936                 int extra_ref = 0;
1937                 int nn = -1;
1938                 int rr, err = 0;
1939
1940                 spin_lock(&mle->spinlock);
1941                 if (mle->type == DLM_MLE_BLOCK || mle->type == DLM_MLE_MIGRATION)
1942                         extra_ref = 1;
1943                 else {
1944                         /* MASTER mle: if any bits set in the response map
1945                          * then the calling node needs to re-assert to clear
1946                          * up nodes that this node contacted */
1947                         while ((nn = find_next_bit (mle->response_map, O2NM_MAX_NODES,
1948                                                     nn+1)) < O2NM_MAX_NODES) {
1949                                 if (nn != dlm->node_num && nn != assert->node_idx) {
1950                                         master_request = 1;
1951                                         break;
1952                                 }
1953                         }
1954                 }
1955                 mle->master = assert->node_idx;
1956                 atomic_set(&mle->woken, 1);
1957                 wake_up(&mle->wq);
1958                 spin_unlock(&mle->spinlock);
1959
1960                 if (res) {
1961                         int wake = 0;
1962                         spin_lock(&res->spinlock);
1963                         if (mle->type == DLM_MLE_MIGRATION) {
1964                                 mlog(0, "finishing off migration of lockres %.*s, "
1965                                         "from %u to %u\n",
1966                                         res->lockname.len, res->lockname.name,
1967                                         dlm->node_num, mle->new_master);
1968                                 res->state &= ~DLM_LOCK_RES_MIGRATING;
1969                                 wake = 1;
1970                                 dlm_change_lockres_owner(dlm, res, mle->new_master);
1971                                 BUG_ON(res->state & DLM_LOCK_RES_DIRTY);
1972                         } else {
1973                                 dlm_change_lockres_owner(dlm, res, mle->master);
1974                         }
1975                         spin_unlock(&res->spinlock);
1976                         have_lockres_ref = 1;
1977                         if (wake)
1978                                 wake_up(&res->wq);
1979                 }
1980
1981                 /* master is known, detach if not already detached.
1982                  * ensures that only one assert_master call will happen
1983                  * on this mle. */
1984                 spin_lock(&dlm->master_lock);
1985
1986                 rr = atomic_read(&mle->mle_refs.refcount);
1987                 if (mle->inuse > 0) {
1988                         if (extra_ref && rr < 3)
1989                                 err = 1;
1990                         else if (!extra_ref && rr < 2)
1991                                 err = 1;
1992                 } else {
1993                         if (extra_ref && rr < 2)
1994                                 err = 1;
1995                         else if (!extra_ref && rr < 1)
1996                                 err = 1;
1997                 }
1998                 if (err) {
1999                         mlog(ML_ERROR, "%s:%.*s: got assert master from %u "
2000                              "that will mess up this node, refs=%d, extra=%d, "
2001                              "inuse=%d\n", dlm->name, namelen, name,
2002                              assert->node_idx, rr, extra_ref, mle->inuse);
2003                         dlm_print_one_mle(mle);
2004                 }
2005                 __dlm_unlink_mle(dlm, mle);
2006                 __dlm_mle_detach_hb_events(dlm, mle);
2007                 __dlm_put_mle(mle);
2008                 if (extra_ref) {
2009                         /* the assert master message now balances the extra
2010                          * ref given by the master / migration request message.
2011                          * if this is the last put, it will be removed
2012                          * from the list. */
2013                         __dlm_put_mle(mle);
2014                 }
2015                 spin_unlock(&dlm->master_lock);
2016         } else if (res) {
2017                 if (res->owner != assert->node_idx) {
2018                         mlog(0, "assert_master from %u, but current "
2019                              "owner is %u (%.*s), no mle\n", assert->node_idx,
2020                              res->owner, namelen, name);
2021                 }
2022         }
2023         spin_unlock(&dlm->spinlock);
2024
2025 done:
2026         ret = 0;
2027         if (res) {
2028                 spin_lock(&res->spinlock);
2029                 res->state |= DLM_LOCK_RES_SETREF_INPROG;
2030                 spin_unlock(&res->spinlock);
2031                 *ret_data = (void *)res;
2032         }
2033         dlm_put(dlm);
2034         if (master_request) {
2035                 mlog(0, "need to tell master to reassert\n");
2036                 /* positive. negative would shoot down the node. */
2037                 ret |= DLM_ASSERT_RESPONSE_REASSERT;
2038                 if (!have_lockres_ref) {
2039                         mlog(ML_ERROR, "strange, got assert from %u, MASTER "
2040                              "mle present here for %s:%.*s, but no lockres!\n",
2041                              assert->node_idx, dlm->name, namelen, name);
2042                 }
2043         }
2044         if (have_lockres_ref) {
2045                 /* let the master know we have a reference to the lockres */
2046                 ret |= DLM_ASSERT_RESPONSE_MASTERY_REF;
2047                 mlog(0, "%s:%.*s: got assert from %u, need a ref\n",
2048                      dlm->name, namelen, name, assert->node_idx);
2049         }
2050         return ret;
2051
2052 kill:
2053         /* kill the caller! */
2054         mlog(ML_ERROR, "Bad message received from another node.  Dumping state "
2055              "and killing the other node now!  This node is OK and can continue.\n");
2056         __dlm_print_one_lock_resource(res);
2057         spin_unlock(&res->spinlock);
2058         spin_lock(&dlm->master_lock);
2059         if (mle)
2060                 __dlm_put_mle(mle);
2061         spin_unlock(&dlm->master_lock);
2062         spin_unlock(&dlm->spinlock);
2063         *ret_data = (void *)res;
2064         dlm_put(dlm);
2065         return -EINVAL;
2066 }
2067
2068 void dlm_assert_master_post_handler(int status, void *data, void *ret_data)
2069 {
2070         struct dlm_lock_resource *res = (struct dlm_lock_resource *)ret_data;
2071
2072         if (ret_data) {
2073                 spin_lock(&res->spinlock);
2074                 res->state &= ~DLM_LOCK_RES_SETREF_INPROG;
2075                 spin_unlock(&res->spinlock);
2076                 wake_up(&res->wq);
2077                 dlm_lockres_put(res);
2078         }
2079         return;
2080 }
2081
2082 int dlm_dispatch_assert_master(struct dlm_ctxt *dlm,
2083                                struct dlm_lock_resource *res,
2084                                int ignore_higher, u8 request_from, u32 flags)
2085 {
2086         struct dlm_work_item *item;
2087         item = kzalloc(sizeof(*item), GFP_ATOMIC);
2088         if (!item)
2089                 return -ENOMEM;
2090
2091
2092         /* queue up work for dlm_assert_master_worker */
2093         dlm_grab(dlm);  /* get an extra ref for the work item */
2094         dlm_init_work_item(dlm, item, dlm_assert_master_worker, NULL);
2095         item->u.am.lockres = res; /* already have a ref */
2096         /* can optionally ignore node numbers higher than this node */
2097         item->u.am.ignore_higher = ignore_higher;
2098         item->u.am.request_from = request_from;
2099         item->u.am.flags = flags;
2100
2101         if (ignore_higher)
2102                 mlog(0, "IGNORE HIGHER: %.*s\n", res->lockname.len,
2103                      res->lockname.name);
2104
2105         spin_lock(&dlm->work_lock);
2106         list_add_tail(&item->list, &dlm->work_list);
2107         spin_unlock(&dlm->work_lock);
2108
2109         queue_work(dlm->dlm_worker, &dlm->dispatched_work);
2110         return 0;
2111 }
2112
2113 static void dlm_assert_master_worker(struct dlm_work_item *item, void *data)
2114 {
2115         struct dlm_ctxt *dlm = data;
2116         int ret = 0;
2117         struct dlm_lock_resource *res;
2118         unsigned long nodemap[BITS_TO_LONGS(O2NM_MAX_NODES)];
2119         int ignore_higher;
2120         int bit;
2121         u8 request_from;
2122         u32 flags;
2123
2124         dlm = item->dlm;
2125         res = item->u.am.lockres;
2126         ignore_higher = item->u.am.ignore_higher;
2127         request_from = item->u.am.request_from;
2128         flags = item->u.am.flags;
2129
2130         spin_lock(&dlm->spinlock);
2131         memcpy(nodemap, dlm->domain_map, sizeof(nodemap));
2132         spin_unlock(&dlm->spinlock);
2133
2134         clear_bit(dlm->node_num, nodemap);
2135         if (ignore_higher) {
2136                 /* if is this just to clear up mles for nodes below
2137                  * this node, do not send the message to the original
2138                  * caller or any node number higher than this */
2139                 clear_bit(request_from, nodemap);
2140                 bit = dlm->node_num;
2141                 while (1) {
2142                         bit = find_next_bit(nodemap, O2NM_MAX_NODES,
2143                                             bit+1);
2144                         if (bit >= O2NM_MAX_NODES)
2145                                 break;
2146                         clear_bit(bit, nodemap);
2147                 }
2148         }
2149
2150         /*
2151          * If we're migrating this lock to someone else, we are no
2152          * longer allowed to assert out own mastery.  OTOH, we need to
2153          * prevent migration from starting while we're still asserting
2154          * our dominance.  The reserved ast delays migration.
2155          */
2156         spin_lock(&res->spinlock);
2157         if (res->state & DLM_LOCK_RES_MIGRATING) {
2158                 mlog(0, "Someone asked us to assert mastery, but we're "
2159                      "in the middle of migration.  Skipping assert, "
2160                      "the new master will handle that.\n");
2161                 spin_unlock(&res->spinlock);
2162                 goto put;
2163         } else
2164                 __dlm_lockres_reserve_ast(res);
2165         spin_unlock(&res->spinlock);
2166
2167         /* this call now finishes out the nodemap
2168          * even if one or more nodes die */
2169         mlog(0, "worker about to master %.*s here, this=%u\n",
2170                      res->lockname.len, res->lockname.name, dlm->node_num);
2171         ret = dlm_do_assert_master(dlm, res, nodemap, flags);
2172         if (ret < 0) {
2173                 /* no need to restart, we are done */
2174                 if (!dlm_is_host_down(ret))
2175                         mlog_errno(ret);
2176         }
2177
2178         /* Ok, we've asserted ourselves.  Let's let migration start. */
2179         dlm_lockres_release_ast(dlm, res);
2180
2181 put:
2182         dlm_lockres_drop_inflight_worker(dlm, res);
2183
2184         dlm_lockres_put(res);
2185
2186         mlog(0, "finished with dlm_assert_master_worker\n");
2187 }
2188
2189 /* SPECIAL CASE for the $RECOVERY lock used by the recovery thread.
2190  * We cannot wait for node recovery to complete to begin mastering this
2191  * lockres because this lockres is used to kick off recovery! ;-)
2192  * So, do a pre-check on all living nodes to see if any of those nodes
2193  * think that $RECOVERY is currently mastered by a dead node.  If so,
2194  * we wait a short time to allow that node to get notified by its own
2195  * heartbeat stack, then check again.  All $RECOVERY lock resources
2196  * mastered by dead nodes are purged when the hearbeat callback is
2197  * fired, so we can know for sure that it is safe to continue once
2198  * the node returns a live node or no node.  */
2199 static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
2200                                        struct dlm_lock_resource *res)
2201 {
2202         struct dlm_node_iter iter;
2203         int nodenum;
2204         int ret = 0;
2205         u8 master = DLM_LOCK_RES_OWNER_UNKNOWN;
2206
2207         spin_lock(&dlm->spinlock);
2208         dlm_node_iter_init(dlm->domain_map, &iter);
2209         spin_unlock(&dlm->spinlock);
2210
2211         while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
2212                 /* do not send to self */
2213                 if (nodenum == dlm->node_num)
2214                         continue;
2215                 ret = dlm_do_master_requery(dlm, res, nodenum, &master);
2216                 if (ret < 0) {
2217                         mlog_errno(ret);
2218                         if (!dlm_is_host_down(ret))
2219                                 BUG();
2220                         /* host is down, so answer for that node would be
2221                          * DLM_LOCK_RES_OWNER_UNKNOWN.  continue. */
2222                         ret = 0;
2223                 }
2224
2225                 if (master != DLM_LOCK_RES_OWNER_UNKNOWN) {
2226                         /* check to see if this master is in the recovery map */
2227                         spin_lock(&dlm->spinlock);
2228                         if (test_bit(master, dlm->recovery_map)) {
2229                                 mlog(ML_NOTICE, "%s: node %u has not seen "
2230                                      "node %u go down yet, and thinks the "
2231                                      "dead node is mastering the recovery "
2232                                      "lock.  must wait.\n", dlm->name,
2233                                      nodenum, master);
2234                                 ret = -EAGAIN;
2235                         }
2236                         spin_unlock(&dlm->spinlock);
2237                         mlog(0, "%s: reco lock master is %u\n", dlm->name,
2238                              master);
2239                         break;
2240                 }
2241         }
2242         return ret;
2243 }
2244
2245 /*
2246  * DLM_DEREF_LOCKRES_MSG
2247  */
2248
2249 int dlm_drop_lockres_ref(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
2250 {
2251         struct dlm_deref_lockres deref;
2252         int ret = 0, r;
2253         const char *lockname;
2254         unsigned int namelen;
2255
2256         lockname = res->lockname.name;
2257         namelen = res->lockname.len;
2258         BUG_ON(namelen > O2NM_MAX_NAME_LEN);
2259
2260         memset(&deref, 0, sizeof(deref));
2261         deref.node_idx = dlm->node_num;
2262         deref.namelen = namelen;
2263         memcpy(deref.name, lockname, namelen);
2264
2265         ret = o2net_send_message(DLM_DEREF_LOCKRES_MSG, dlm->key,
2266                                  &deref, sizeof(deref), res->owner, &r);
2267         if (ret < 0)
2268                 mlog(ML_ERROR, "%s: res %.*s, error %d send DEREF to node %u\n",
2269                      dlm->name, namelen, lockname, ret, res->owner);
2270         else if (r < 0) {
2271                 /* BAD.  other node says I did not have a ref. */
2272                 mlog(ML_ERROR, "%s: res %.*s, DEREF to node %u got %d\n",
2273                      dlm->name, namelen, lockname, res->owner, r);
2274                 dlm_print_one_lock_resource(res);
2275                 BUG();
2276         }
2277         return ret;
2278 }
2279
2280 int dlm_deref_lockres_handler(struct o2net_msg *msg, u32 len, void *data,
2281                               void **ret_data)
2282 {
2283         struct dlm_ctxt *dlm = data;
2284         struct dlm_deref_lockres *deref = (struct dlm_deref_lockres *)msg->buf;
2285         struct dlm_lock_resource *res = NULL;
2286         char *name;
2287         unsigned int namelen;
2288         int ret = -EINVAL;
2289         u8 node;
2290         unsigned int hash;
2291         struct dlm_work_item *item;
2292         int cleared = 0;
2293         int dispatch = 0;
2294
2295         if (!dlm_grab(dlm))
2296                 return 0;
2297
2298         name = deref->name;
2299         namelen = deref->namelen;
2300         node = deref->node_idx;
2301
2302         if (namelen > DLM_LOCKID_NAME_MAX) {
2303                 mlog(ML_ERROR, "Invalid name length!");
2304                 goto done;
2305         }
2306         if (deref->node_idx >= O2NM_MAX_NODES) {
2307                 mlog(ML_ERROR, "Invalid node number: %u\n", node);
2308                 goto done;
2309         }
2310
2311         hash = dlm_lockid_hash(name, namelen);
2312
2313         spin_lock(&dlm->spinlock);
2314         res = __dlm_lookup_lockres_full(dlm, name, namelen, hash);
2315         if (!res) {
2316                 spin_unlock(&dlm->spinlock);
2317                 mlog(ML_ERROR, "%s:%.*s: bad lockres name\n",
2318                      dlm->name, namelen, name);
2319                 goto done;
2320         }
2321         spin_unlock(&dlm->spinlock);
2322
2323         spin_lock(&res->spinlock);
2324         if (res->state & DLM_LOCK_RES_SETREF_INPROG)
2325                 dispatch = 1;
2326         else {
2327                 BUG_ON(res->state & DLM_LOCK_RES_DROPPING_REF);
2328                 if (test_bit(node, res->refmap)) {
2329                         dlm_lockres_clear_refmap_bit(dlm, res, node);
2330                         cleared = 1;
2331                 }
2332         }
2333         spin_unlock(&res->spinlock);
2334
2335         if (!dispatch) {
2336                 if (cleared)
2337                         dlm_lockres_calc_usage(dlm, res);
2338                 else {
2339                         mlog(ML_ERROR, "%s:%.*s: node %u trying to drop ref "
2340                         "but it is already dropped!\n", dlm->name,
2341                         res->lockname.len, res->lockname.name, node);
2342                         dlm_print_one_lock_resource(res);
2343                 }
2344                 ret = 0;
2345                 goto done;
2346         }
2347
2348         item = kzalloc(sizeof(*item), GFP_NOFS);
2349         if (!item) {
2350                 ret = -ENOMEM;
2351                 mlog_errno(ret);
2352                 goto done;
2353         }
2354
2355         dlm_init_work_item(dlm, item, dlm_deref_lockres_worker, NULL);
2356         item->u.dl.deref_res = res;
2357         item->u.dl.deref_node = node;
2358
2359         spin_lock(&dlm->work_lock);
2360         list_add_tail(&item->list, &dlm->work_list);
2361         spin_unlock(&dlm->work_lock);
2362
2363         queue_work(dlm->dlm_worker, &dlm->dispatched_work);
2364         return 0;
2365
2366 done:
2367         if (res)
2368                 dlm_lockres_put(res);
2369         dlm_put(dlm);
2370
2371         return ret;
2372 }
2373
2374 static void dlm_deref_lockres_worker(struct dlm_work_item *item, void *data)
2375 {
2376         struct dlm_ctxt *dlm;
2377         struct dlm_lock_resource *res;
2378         u8 node;
2379         u8 cleared = 0;
2380
2381         dlm = item->dlm;
2382         res = item->u.dl.deref_res;
2383         node = item->u.dl.deref_node;
2384
2385         spin_lock(&res->spinlock);
2386         BUG_ON(res->state & DLM_LOCK_RES_DROPPING_REF);
2387         if (test_bit(node, res->refmap)) {
2388                 __dlm_wait_on_lockres_flags(res, DLM_LOCK_RES_SETREF_INPROG);
2389                 dlm_lockres_clear_refmap_bit(dlm, res, node);
2390                 cleared = 1;
2391         }
2392         spin_unlock(&res->spinlock);
2393
2394         if (cleared) {
2395                 mlog(0, "%s:%.*s node %u ref dropped in dispatch\n",
2396                      dlm->name, res->lockname.len, res->lockname.name, node);
2397                 dlm_lockres_calc_usage(dlm, res);
2398         } else {
2399                 mlog(ML_ERROR, "%s:%.*s: node %u trying to drop ref "
2400                      "but it is already dropped!\n", dlm->name,
2401                      res->lockname.len, res->lockname.name, node);
2402                 dlm_print_one_lock_resource(res);
2403         }
2404
2405         dlm_lockres_put(res);
2406 }
2407
2408 /*
2409  * A migrateable resource is one that is :
2410  * 1. locally mastered, and,
2411  * 2. zero local locks, and,
2412  * 3. one or more non-local locks, or, one or more references
2413  * Returns 1 if yes, 0 if not.
2414  */
2415 static int dlm_is_lockres_migrateable(struct dlm_ctxt *dlm,
2416                                       struct dlm_lock_resource *res)
2417 {
2418         enum dlm_lockres_list idx;
2419         int nonlocal = 0, node_ref;
2420         struct list_head *queue;
2421         struct dlm_lock *lock;
2422         u64 cookie;
2423
2424         assert_spin_locked(&res->spinlock);
2425
2426         /* delay migration when the lockres is in MIGRATING state */
2427         if (res->state & DLM_LOCK_RES_MIGRATING)
2428                 return 0;
2429
2430         /* delay migration when the lockres is in RECOCERING state */
2431         if (res->state & DLM_LOCK_RES_RECOVERING)
2432                 return 0;
2433
2434         if (res->owner != dlm->node_num)
2435                 return 0;
2436
2437         for (idx = DLM_GRANTED_LIST; idx <= DLM_BLOCKED_LIST; idx++) {
2438                 queue = dlm_list_idx_to_ptr(res, idx);
2439                 list_for_each_entry(lock, queue, list) {
2440                         if (lock->ml.node != dlm->node_num) {
2441                                 nonlocal++;
2442                                 continue;
2443                         }
2444                         cookie = be64_to_cpu(lock->ml.cookie);
2445                         mlog(0, "%s: Not migrateable res %.*s, lock %u:%llu on "
2446                              "%s list\n", dlm->name, res->lockname.len,
2447                              res->lockname.name,
2448                              dlm_get_lock_cookie_node(cookie),
2449                              dlm_get_lock_cookie_seq(cookie),
2450                              dlm_list_in_text(idx));
2451                         return 0;
2452                 }
2453         }
2454
2455         if (!nonlocal) {
2456                 node_ref = find_next_bit(res->refmap, O2NM_MAX_NODES, 0);
2457                 if (node_ref >= O2NM_MAX_NODES)
2458                         return 0;
2459         }
2460
2461         mlog(0, "%s: res %.*s, Migrateable\n", dlm->name, res->lockname.len,
2462              res->lockname.name);
2463
2464         return 1;
2465 }
2466
2467 /*
2468  * DLM_MIGRATE_LOCKRES
2469  */
2470
2471
2472 static int dlm_migrate_lockres(struct dlm_ctxt *dlm,
2473                                struct dlm_lock_resource *res, u8 target)
2474 {
2475         struct dlm_master_list_entry *mle = NULL;
2476         struct dlm_master_list_entry *oldmle = NULL;
2477         struct dlm_migratable_lockres *mres = NULL;
2478         int ret = 0;
2479         const char *name;
2480         unsigned int namelen;
2481         int mle_added = 0;
2482         int wake = 0;
2483
2484         if (!dlm_grab(dlm))
2485                 return -EINVAL;
2486
2487         BUG_ON(target == O2NM_MAX_NODES);
2488
2489         name = res->lockname.name;
2490         namelen = res->lockname.len;
2491
2492         mlog(0, "%s: Migrating %.*s to node %u\n", dlm->name, namelen, name,
2493              target);
2494
2495         /* preallocate up front. if this fails, abort */
2496         ret = -ENOMEM;
2497         mres = (struct dlm_migratable_lockres *) __get_free_page(GFP_NOFS);
2498         if (!mres) {
2499                 mlog_errno(ret);
2500                 goto leave;
2501         }
2502
2503         mle = kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
2504         if (!mle) {
2505                 mlog_errno(ret);
2506                 goto leave;
2507         }
2508         ret = 0;
2509
2510         /*
2511          * clear any existing master requests and
2512          * add the migration mle to the list
2513          */
2514         spin_lock(&dlm->spinlock);
2515         spin_lock(&dlm->master_lock);
2516         ret = dlm_add_migration_mle(dlm, res, mle, &oldmle, name,
2517                                     namelen, target, dlm->node_num);
2518         spin_unlock(&dlm->master_lock);
2519         spin_unlock(&dlm->spinlock);
2520
2521         if (ret == -EEXIST) {
2522                 mlog(0, "another process is already migrating it\n");
2523                 goto fail;
2524         }
2525         mle_added = 1;
2526
2527         /*
2528          * set the MIGRATING flag and flush asts
2529          * if we fail after this we need to re-dirty the lockres
2530          */
2531         if (dlm_mark_lockres_migrating(dlm, res, target) < 0) {
2532                 mlog(ML_ERROR, "tried to migrate %.*s to %u, but "
2533                      "the target went down.\n", res->lockname.len,
2534                      res->lockname.name, target);
2535                 spin_lock(&res->spinlock);
2536                 res->state &= ~DLM_LOCK_RES_MIGRATING;
2537                 wake = 1;
2538                 spin_unlock(&res->spinlock);
2539                 ret = -EINVAL;
2540         }
2541
2542 fail:
2543         if (oldmle) {
2544                 /* master is known, detach if not already detached */
2545                 dlm_mle_detach_hb_events(dlm, oldmle);
2546                 dlm_put_mle(oldmle);
2547         }
2548
2549         if (ret < 0) {
2550                 if (mle_added) {
2551                         dlm_mle_detach_hb_events(dlm, mle);
2552                         dlm_put_mle(mle);
2553                 } else if (mle) {
2554                         kmem_cache_free(dlm_mle_cache, mle);
2555                         mle = NULL;
2556                 }
2557                 goto leave;
2558         }
2559
2560         /*
2561          * at this point, we have a migration target, an mle
2562          * in the master list, and the MIGRATING flag set on
2563          * the lockres
2564          */
2565
2566         /* now that remote nodes are spinning on the MIGRATING flag,
2567          * ensure that all assert_master work is flushed. */
2568         flush_workqueue(dlm->dlm_worker);
2569
2570         /* get an extra reference on the mle.
2571          * otherwise the assert_master from the new
2572          * master will destroy this.
2573          * also, make sure that all callers of dlm_get_mle
2574          * take both dlm->spinlock and dlm->master_lock */
2575         spin_lock(&dlm->spinlock);
2576         spin_lock(&dlm->master_lock);
2577         dlm_get_mle_inuse(mle);
2578         spin_unlock(&dlm->master_lock);
2579         spin_unlock(&dlm->spinlock);
2580
2581         /* notify new node and send all lock state */
2582         /* call send_one_lockres with migration flag.
2583          * this serves as notice to the target node that a
2584          * migration is starting. */
2585         ret = dlm_send_one_lockres(dlm, res, mres, target,
2586                                    DLM_MRES_MIGRATION);
2587
2588         if (ret < 0) {
2589                 mlog(0, "migration to node %u failed with %d\n",
2590                      target, ret);
2591                 /* migration failed, detach and clean up mle */
2592                 dlm_mle_detach_hb_events(dlm, mle);
2593                 dlm_put_mle(mle);
2594                 dlm_put_mle_inuse(mle);
2595                 spin_lock(&res->spinlock);
2596                 res->state &= ~DLM_LOCK_RES_MIGRATING;
2597                 wake = 1;
2598                 spin_unlock(&res->spinlock);
2599                 if (dlm_is_host_down(ret))
2600                         dlm_wait_for_node_death(dlm, target,
2601                                                 DLM_NODE_DEATH_WAIT_MAX);
2602                 goto leave;
2603         }
2604
2605         /* at this point, the target sends a message to all nodes,
2606          * (using dlm_do_migrate_request).  this node is skipped since
2607          * we had to put an mle in the list to begin the process.  this
2608          * node now waits for target to do an assert master.  this node
2609          * will be the last one notified, ensuring that the migration
2610          * is complete everywhere.  if the target dies while this is
2611          * going on, some nodes could potentially see the target as the
2612          * master, so it is important that my recovery finds the migration
2613          * mle and sets the master to UNKNOWN. */
2614
2615
2616         /* wait for new node to assert master */
2617         while (1) {
2618                 ret = wait_event_interruptible_timeout(mle->wq,
2619                                         (atomic_read(&mle->woken) == 1),
2620                                         msecs_to_jiffies(5000));
2621
2622                 if (ret >= 0) {
2623                         if (atomic_read(&mle->woken) == 1 ||
2624                             res->owner == target)
2625                                 break;
2626
2627                         mlog(0, "%s:%.*s: timed out during migration\n",
2628                              dlm->name, res->lockname.len, res->lockname.name);
2629                         /* avoid hang during shutdown when migrating lockres
2630                          * to a node which also goes down */
2631                         if (dlm_is_node_dead(dlm, target)) {
2632                                 mlog(0, "%s:%.*s: expected migration "
2633                                      "target %u is no longer up, restarting\n",
2634                                      dlm->name, res->lockname.len,
2635                                      res->lockname.name, target);
2636                                 ret = -EINVAL;
2637                                 /* migration failed, detach and clean up mle */
2638                                 dlm_mle_detach_hb_events(dlm, mle);
2639                                 dlm_put_mle(mle);
2640                                 dlm_put_mle_inuse(mle);
2641                                 spin_lock(&res->spinlock);
2642                                 res->state &= ~DLM_LOCK_RES_MIGRATING;
2643                                 wake = 1;
2644                                 spin_unlock(&res->spinlock);
2645                                 goto leave;
2646                         }
2647                 } else
2648                         mlog(0, "%s:%.*s: caught signal during migration\n",
2649                              dlm->name, res->lockname.len, res->lockname.name);
2650         }
2651
2652         /* all done, set the owner, clear the flag */
2653         spin_lock(&res->spinlock);
2654         dlm_set_lockres_owner(dlm, res, target);
2655         res->state &= ~DLM_LOCK_RES_MIGRATING;
2656         dlm_remove_nonlocal_locks(dlm, res);
2657         spin_unlock(&res->spinlock);
2658         wake_up(&res->wq);
2659
2660         /* master is known, detach if not already detached */
2661         dlm_mle_detach_hb_events(dlm, mle);
2662         dlm_put_mle_inuse(mle);
2663         ret = 0;
2664
2665         dlm_lockres_calc_usage(dlm, res);
2666
2667 leave:
2668         /* re-dirty the lockres if we failed */
2669         if (ret < 0)
2670                 dlm_kick_thread(dlm, res);
2671
2672         /* wake up waiters if the MIGRATING flag got set
2673          * but migration failed */
2674         if (wake)
2675                 wake_up(&res->wq);
2676
2677         if (mres)
2678                 free_page((unsigned long)mres);
2679
2680         dlm_put(dlm);
2681
2682         mlog(0, "%s: Migrating %.*s to %u, returns %d\n", dlm->name, namelen,
2683              name, target, ret);
2684         return ret;
2685 }
2686
2687 #define DLM_MIGRATION_RETRY_MS  100
2688
2689 /*
2690  * Should be called only after beginning the domain leave process.
2691  * There should not be any remaining locks on nonlocal lock resources,
2692  * and there should be no local locks left on locally mastered resources.
2693  *
2694  * Called with the dlm spinlock held, may drop it to do migration, but
2695  * will re-acquire before exit.
2696  *
2697  * Returns: 1 if dlm->spinlock was dropped/retaken, 0 if never dropped
2698  */
2699 int dlm_empty_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
2700 {
2701         int ret;
2702         int lock_dropped = 0;
2703         u8 target = O2NM_MAX_NODES;
2704
2705         assert_spin_locked(&dlm->spinlock);
2706
2707         spin_lock(&res->spinlock);
2708         if (dlm_is_lockres_migrateable(dlm, res))
2709                 target = dlm_pick_migration_target(dlm, res);
2710         spin_unlock(&res->spinlock);
2711
2712         if (target == O2NM_MAX_NODES)
2713                 goto leave;
2714
2715         /* Wheee! Migrate lockres here! Will sleep so drop spinlock. */
2716         spin_unlock(&dlm->spinlock);
2717         lock_dropped = 1;
2718         ret = dlm_migrate_lockres(dlm, res, target);
2719         if (ret)
2720                 mlog(0, "%s: res %.*s, Migrate to node %u failed with %d\n",
2721                      dlm->name, res->lockname.len, res->lockname.name,
2722                      target, ret);
2723         spin_lock(&dlm->spinlock);
2724 leave:
2725         return lock_dropped;
2726 }
2727
2728 int dlm_lock_basts_flushed(struct dlm_ctxt *dlm, struct dlm_lock *lock)
2729 {
2730         int ret;
2731         spin_lock(&dlm->ast_lock);
2732         spin_lock(&lock->spinlock);
2733         ret = (list_empty(&lock->bast_list) && !lock->bast_pending);
2734         spin_unlock(&lock->spinlock);
2735         spin_unlock(&dlm->ast_lock);
2736         return ret;
2737 }
2738
2739 static int dlm_migration_can_proceed(struct dlm_ctxt *dlm,
2740                                      struct dlm_lock_resource *res,
2741                                      u8 mig_target)
2742 {
2743         int can_proceed;
2744         spin_lock(&res->spinlock);
2745         can_proceed = !!(res->state & DLM_LOCK_RES_MIGRATING);
2746         spin_unlock(&res->spinlock);
2747
2748         /* target has died, so make the caller break out of the
2749          * wait_event, but caller must recheck the domain_map */
2750         spin_lock(&dlm->spinlock);
2751         if (!test_bit(mig_target, dlm->domain_map))
2752                 can_proceed = 1;
2753         spin_unlock(&dlm->spinlock);
2754         return can_proceed;
2755 }
2756
2757 static int dlm_lockres_is_dirty(struct dlm_ctxt *dlm,
2758                                 struct dlm_lock_resource *res)
2759 {
2760         int ret;
2761         spin_lock(&res->spinlock);
2762         ret = !!(res->state & DLM_LOCK_RES_DIRTY);
2763         spin_unlock(&res->spinlock);
2764         return ret;
2765 }
2766
2767
2768 static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
2769                                        struct dlm_lock_resource *res,
2770                                        u8 target)
2771 {
2772         int ret = 0;
2773
2774         mlog(0, "dlm_mark_lockres_migrating: %.*s, from %u to %u\n",
2775                res->lockname.len, res->lockname.name, dlm->node_num,
2776                target);
2777         /* need to set MIGRATING flag on lockres.  this is done by
2778          * ensuring that all asts have been flushed for this lockres. */
2779         spin_lock(&res->spinlock);
2780         BUG_ON(res->migration_pending);
2781         res->migration_pending = 1;
2782         /* strategy is to reserve an extra ast then release
2783          * it below, letting the release do all of the work */
2784         __dlm_lockres_reserve_ast(res);
2785         spin_unlock(&res->spinlock);
2786
2787         /* now flush all the pending asts */
2788         dlm_kick_thread(dlm, res);
2789         /* before waiting on DIRTY, block processes which may
2790          * try to dirty the lockres before MIGRATING is set */
2791         spin_lock(&res->spinlock);
2792         BUG_ON(res->state & DLM_LOCK_RES_BLOCK_DIRTY);
2793         res->state |= DLM_LOCK_RES_BLOCK_DIRTY;
2794         spin_unlock(&res->spinlock);
2795         /* now wait on any pending asts and the DIRTY state */
2796         wait_event(dlm->ast_wq, !dlm_lockres_is_dirty(dlm, res));
2797         dlm_lockres_release_ast(dlm, res);
2798
2799         mlog(0, "about to wait on migration_wq, dirty=%s\n",
2800                res->state & DLM_LOCK_RES_DIRTY ? "yes" : "no");
2801         /* if the extra ref we just put was the final one, this
2802          * will pass thru immediately.  otherwise, we need to wait
2803          * for the last ast to finish. */
2804 again:
2805         ret = wait_event_interruptible_timeout(dlm->migration_wq,
2806                    dlm_migration_can_proceed(dlm, res, target),
2807                    msecs_to_jiffies(1000));
2808         if (ret < 0) {
2809                 mlog(0, "woken again: migrating? %s, dead? %s\n",
2810                        res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
2811                        test_bit(target, dlm->domain_map) ? "no":"yes");
2812         } else {
2813                 mlog(0, "all is well: migrating? %s, dead? %s\n",
2814                        res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
2815                        test_bit(target, dlm->domain_map) ? "no":"yes");
2816         }
2817         if (!dlm_migration_can_proceed(dlm, res, target)) {
2818                 mlog(0, "trying again...\n");
2819                 goto again;
2820         }
2821
2822         ret = 0;
2823         /* did the target go down or die? */
2824         spin_lock(&dlm->spinlock);
2825         if (!test_bit(target, dlm->domain_map)) {
2826                 mlog(ML_ERROR, "aha. migration target %u just went down\n",
2827                      target);
2828                 ret = -EHOSTDOWN;
2829         }
2830         spin_unlock(&dlm->spinlock);
2831
2832         /*
2833          * if target is down, we need to clear DLM_LOCK_RES_BLOCK_DIRTY for
2834          * another try; otherwise, we are sure the MIGRATING state is there,
2835          * drop the unneded state which blocked threads trying to DIRTY
2836          */
2837         spin_lock(&res->spinlock);
2838         BUG_ON(!(res->state & DLM_LOCK_RES_BLOCK_DIRTY));
2839         res->state &= ~DLM_LOCK_RES_BLOCK_DIRTY;
2840         if (!ret)
2841                 BUG_ON(!(res->state & DLM_LOCK_RES_MIGRATING));
2842         spin_unlock(&res->spinlock);
2843
2844         /*
2845          * at this point:
2846          *
2847          *   o the DLM_LOCK_RES_MIGRATING flag is set if target not down
2848          *   o there are no pending asts on this lockres
2849          *   o all processes trying to reserve an ast on this
2850          *     lockres must wait for the MIGRATING flag to clear
2851          */
2852         return ret;
2853 }
2854
2855 /* last step in the migration process.
2856  * original master calls this to free all of the dlm_lock
2857  * structures that used to be for other nodes. */
2858 static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
2859                                       struct dlm_lock_resource *res)
2860 {
2861         struct list_head *queue = &res->granted;
2862         int i, bit;
2863         struct dlm_lock *lock, *next;
2864
2865         assert_spin_locked(&res->spinlock);
2866
2867         BUG_ON(res->owner == dlm->node_num);
2868
2869         for (i=0; i<3; i++) {
2870                 list_for_each_entry_safe(lock, next, queue, list) {
2871                         if (lock->ml.node != dlm->node_num) {
2872                                 mlog(0, "putting lock for node %u\n",
2873                                      lock->ml.node);
2874                                 /* be extra careful */
2875                                 BUG_ON(!list_empty(&lock->ast_list));
2876                                 BUG_ON(!list_empty(&lock->bast_list));
2877                                 BUG_ON(lock->ast_pending);
2878                                 BUG_ON(lock->bast_pending);
2879                                 dlm_lockres_clear_refmap_bit(dlm, res,
2880                                                              lock->ml.node);
2881                                 list_del_init(&lock->list);
2882                                 dlm_lock_put(lock);
2883                                 /* In a normal unlock, we would have added a
2884                                  * DLM_UNLOCK_FREE_LOCK action. Force it. */
2885                                 dlm_lock_put(lock);
2886                         }
2887                 }
2888                 queue++;
2889         }
2890         bit = 0;
2891         while (1) {
2892                 bit = find_next_bit(res->refmap, O2NM_MAX_NODES, bit);
2893                 if (bit >= O2NM_MAX_NODES)
2894                         break;
2895                 /* do not clear the local node reference, if there is a
2896                  * process holding this, let it drop the ref itself */
2897                 if (bit != dlm->node_num) {
2898                         mlog(0, "%s:%.*s: node %u had a ref to this "
2899                              "migrating lockres, clearing\n", dlm->name,
2900                              res->lockname.len, res->lockname.name, bit);
2901                         dlm_lockres_clear_refmap_bit(dlm, res, bit);
2902                 }
2903                 bit++;
2904         }
2905 }
2906
2907 /*
2908  * Pick a node to migrate the lock resource to. This function selects a
2909  * potential target based first on the locks and then on refmap. It skips
2910  * nodes that are in the process of exiting the domain.
2911  */
2912 static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
2913                                     struct dlm_lock_resource *res)
2914 {
2915         enum dlm_lockres_list idx;
2916         struct list_head *queue = &res->granted;
2917         struct dlm_lock *lock;
2918         int noderef;
2919         u8 nodenum = O2NM_MAX_NODES;
2920
2921         assert_spin_locked(&dlm->spinlock);
2922         assert_spin_locked(&res->spinlock);
2923
2924         /* Go through all the locks */
2925         for (idx = DLM_GRANTED_LIST; idx <= DLM_BLOCKED_LIST; idx++) {
2926                 queue = dlm_list_idx_to_ptr(res, idx);
2927                 list_for_each_entry(lock, queue, list) {
2928                         if (lock->ml.node == dlm->node_num)
2929                                 continue;
2930                         if (test_bit(lock->ml.node, dlm->exit_domain_map))
2931                                 continue;
2932                         nodenum = lock->ml.node;
2933                         goto bail;
2934                 }
2935         }
2936
2937         /* Go thru the refmap */
2938         noderef = -1;
2939         while (1) {
2940                 noderef = find_next_bit(res->refmap, O2NM_MAX_NODES,
2941                                         noderef + 1);
2942                 if (noderef >= O2NM_MAX_NODES)
2943                         break;
2944                 if (noderef == dlm->node_num)
2945                         continue;
2946                 if (test_bit(noderef, dlm->exit_domain_map))
2947                         continue;
2948                 nodenum = noderef;
2949                 goto bail;
2950         }
2951
2952 bail:
2953         return nodenum;
2954 }
2955
2956 /* this is called by the new master once all lockres
2957  * data has been received */
2958 static int dlm_do_migrate_request(struct dlm_ctxt *dlm,
2959                                   struct dlm_lock_resource *res,
2960                                   u8 master, u8 new_master,
2961                                   struct dlm_node_iter *iter)
2962 {
2963         struct dlm_migrate_request migrate;
2964         int ret, skip, status = 0;
2965         int nodenum;
2966
2967         memset(&migrate, 0, sizeof(migrate));
2968         migrate.namelen = res->lockname.len;
2969         memcpy(migrate.name, res->lockname.name, migrate.namelen);
2970         migrate.new_master = new_master;
2971         migrate.master = master;
2972
2973         ret = 0;
2974
2975         /* send message to all nodes, except the master and myself */
2976         while ((nodenum = dlm_node_iter_next(iter)) >= 0) {
2977                 if (nodenum == master ||
2978                     nodenum == new_master)
2979                         continue;
2980
2981                 /* We could race exit domain. If exited, skip. */
2982                 spin_lock(&dlm->spinlock);
2983                 skip = (!test_bit(nodenum, dlm->domain_map));
2984                 spin_unlock(&dlm->spinlock);
2985                 if (skip) {
2986                         clear_bit(nodenum, iter->node_map);
2987                         continue;
2988                 }
2989
2990                 ret = o2net_send_message(DLM_MIGRATE_REQUEST_MSG, dlm->key,
2991                                          &migrate, sizeof(migrate), nodenum,
2992                                          &status);
2993                 if (ret < 0) {
2994                         mlog(ML_ERROR, "%s: res %.*s, Error %d send "
2995                              "MIGRATE_REQUEST to node %u\n", dlm->name,
2996                              migrate.namelen, migrate.name, ret, nodenum);
2997                         if (!dlm_is_host_down(ret)) {
2998                                 mlog(ML_ERROR, "unhandled error=%d!\n", ret);
2999                                 BUG();
3000                         }
3001                         clear_bit(nodenum, iter->node_map);
3002                         ret = 0;
3003                 } else if (status < 0) {
3004                         mlog(0, "migrate request (node %u) returned %d!\n",
3005                              nodenum, status);
3006                         ret = status;
3007                 } else if (status == DLM_MIGRATE_RESPONSE_MASTERY_REF) {
3008                         /* during the migration request we short-circuited
3009                          * the mastery of the lockres.  make sure we have
3010                          * a mastery ref for nodenum */
3011                         mlog(0, "%s:%.*s: need ref for node %u\n",
3012                              dlm->name, res->lockname.len, res->lockname.name,
3013                              nodenum);
3014                         spin_lock(&res->spinlock);
3015                         dlm_lockres_set_refmap_bit(dlm, res, nodenum);
3016                         spin_unlock(&res->spinlock);
3017                 }
3018         }
3019
3020         if (ret < 0)
3021                 mlog_errno(ret);
3022
3023         mlog(0, "returning ret=%d\n", ret);
3024         return ret;
3025 }
3026
3027
3028 /* if there is an existing mle for this lockres, we now know who the master is.
3029  * (the one who sent us *this* message) we can clear it up right away.
3030  * since the process that put the mle on the list still has a reference to it,
3031  * we can unhash it now, set the master and wake the process.  as a result,
3032  * we will have no mle in the list to start with.  now we can add an mle for
3033  * the migration and this should be the only one found for those scanning the
3034  * list.  */
3035 int dlm_migrate_request_handler(struct o2net_msg *msg, u32 len, void *data,
3036                                 void **ret_data)
3037 {
3038         struct dlm_ctxt *dlm = data;
3039         struct dlm_lock_resource *res = NULL;
3040         struct dlm_migrate_request *migrate = (struct dlm_migrate_request *) msg->buf;
3041         struct dlm_master_list_entry *mle = NULL, *oldmle = NULL;
3042         const char *name;
3043         unsigned int namelen, hash;
3044         int ret = 0;
3045
3046         if (!dlm_grab(dlm))
3047                 return -EINVAL;
3048
3049         name = migrate->name;
3050         namelen = migrate->namelen;
3051         hash = dlm_lockid_hash(name, namelen);
3052
3053         /* preallocate.. if this fails, abort */
3054         mle = kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
3055
3056         if (!mle) {
3057                 ret = -ENOMEM;
3058                 goto leave;
3059         }
3060
3061         /* check for pre-existing lock */
3062         spin_lock(&dlm->spinlock);
3063         res = __dlm_lookup_lockres(dlm, name, namelen, hash);
3064         if (res) {
3065                 spin_lock(&res->spinlock);
3066                 if (res->state & DLM_LOCK_RES_RECOVERING) {
3067                         /* if all is working ok, this can only mean that we got
3068                         * a migrate request from a node that we now see as
3069                         * dead.  what can we do here?  drop it to the floor? */
3070                         spin_unlock(&res->spinlock);
3071                         mlog(ML_ERROR, "Got a migrate request, but the "
3072                              "lockres is marked as recovering!");
3073                         kmem_cache_free(dlm_mle_cache, mle);
3074                         ret = -EINVAL; /* need a better solution */
3075                         goto unlock;
3076                 }
3077                 res->state |= DLM_LOCK_RES_MIGRATING;
3078                 spin_unlock(&res->spinlock);
3079         }
3080
3081         spin_lock(&dlm->master_lock);
3082         /* ignore status.  only nonzero status would BUG. */
3083         ret = dlm_add_migration_mle(dlm, res, mle, &oldmle,
3084                                     name, namelen,
3085                                     migrate->new_master,
3086                                     migrate->master);
3087
3088         spin_unlock(&dlm->master_lock);
3089 unlock:
3090         spin_unlock(&dlm->spinlock);
3091
3092         if (oldmle) {
3093                 /* master is known, detach if not already detached */
3094                 dlm_mle_detach_hb_events(dlm, oldmle);
3095                 dlm_put_mle(oldmle);
3096         }
3097
3098         if (res)
3099                 dlm_lockres_put(res);
3100 leave:
3101         dlm_put(dlm);
3102         return ret;
3103 }
3104
3105 /* must be holding dlm->spinlock and dlm->master_lock
3106  * when adding a migration mle, we can clear any other mles
3107  * in the master list because we know with certainty that
3108  * the master is "master".  so we remove any old mle from
3109  * the list after setting it's master field, and then add
3110  * the new migration mle.  this way we can hold with the rule
3111  * of having only one mle for a given lock name at all times. */
3112 static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
3113                                  struct dlm_lock_resource *res,
3114                                  struct dlm_master_list_entry *mle,
3115                                  struct dlm_master_list_entry **oldmle,
3116                                  const char *name, unsigned int namelen,
3117                                  u8 new_master, u8 master)
3118 {
3119         int found;
3120         int ret = 0;
3121
3122         *oldmle = NULL;
3123
3124         assert_spin_locked(&dlm->spinlock);
3125         assert_spin_locked(&dlm->master_lock);
3126
3127         /* caller is responsible for any ref taken here on oldmle */
3128         found = dlm_find_mle(dlm, oldmle, (char *)name, namelen);
3129         if (found) {
3130                 struct dlm_master_list_entry *tmp = *oldmle;
3131                 spin_lock(&tmp->spinlock);
3132                 if (tmp->type == DLM_MLE_MIGRATION) {
3133                         if (master == dlm->node_num) {
3134                                 /* ah another process raced me to it */
3135                                 mlog(0, "tried to migrate %.*s, but some "
3136                                      "process beat me to it\n",
3137                                      namelen, name);
3138                                 ret = -EEXIST;
3139                         } else {
3140                                 /* bad.  2 NODES are trying to migrate! */
3141                                 mlog(ML_ERROR, "migration error  mle: "
3142                                      "master=%u new_master=%u // request: "
3143                                      "master=%u new_master=%u // "
3144                                      "lockres=%.*s\n",
3145                                      tmp->master, tmp->new_master,
3146                                      master, new_master,
3147                                      namelen, name);
3148                                 BUG();
3149                         }
3150                 } else {
3151                         /* this is essentially what assert_master does */
3152                         tmp->master = master;
3153                         atomic_set(&tmp->woken, 1);
3154                         wake_up(&tmp->wq);
3155                         /* remove it so that only one mle will be found */
3156                         __dlm_unlink_mle(dlm, tmp);
3157                         __dlm_mle_detach_hb_events(dlm, tmp);
3158                         if (tmp->type == DLM_MLE_MASTER) {
3159                                 ret = DLM_MIGRATE_RESPONSE_MASTERY_REF;
3160                                 mlog(0, "%s:%.*s: master=%u, newmaster=%u, "
3161                                                 "telling master to get ref "
3162                                                 "for cleared out mle during "
3163                                                 "migration\n", dlm->name,
3164                                                 namelen, name, master,
3165                                                 new_master);
3166                         }
3167                 }
3168                 spin_unlock(&tmp->spinlock);
3169         }
3170
3171         /* now add a migration mle to the tail of the list */
3172         dlm_init_mle(mle, DLM_MLE_MIGRATION, dlm, res, name, namelen);
3173         mle->new_master = new_master;
3174         /* the new master will be sending an assert master for this.
3175          * at that point we will get the refmap reference */
3176         mle->master = master;
3177         /* do this for consistency with other mle types */
3178         set_bit(new_master, mle->maybe_map);
3179         __dlm_insert_mle(dlm, mle);
3180
3181         return ret;
3182 }
3183
3184 /*
3185  * Sets the owner of the lockres, associated to the mle, to UNKNOWN
3186  */
3187 static struct dlm_lock_resource *dlm_reset_mleres_owner(struct dlm_ctxt *dlm,
3188                                         struct dlm_master_list_entry *mle)
3189 {
3190         struct dlm_lock_resource *res;
3191
3192         /* Find the lockres associated to the mle and set its owner to UNK */
3193         res = __dlm_lookup_lockres(dlm, mle->mname, mle->mnamelen,
3194                                    mle->mnamehash);
3195         if (res) {
3196                 spin_unlock(&dlm->master_lock);
3197
3198                 /* move lockres onto recovery list */
3199                 spin_lock(&res->spinlock);
3200                 dlm_set_lockres_owner(dlm, res, DLM_LOCK_RES_OWNER_UNKNOWN);
3201                 dlm_move_lockres_to_recovery_list(dlm, res);
3202                 spin_unlock(&res->spinlock);
3203                 dlm_lockres_put(res);
3204
3205                 /* about to get rid of mle, detach from heartbeat */
3206                 __dlm_mle_detach_hb_events(dlm, mle);
3207
3208                 /* dump the mle */
3209                 spin_lock(&dlm->master_lock);
3210                 __dlm_put_mle(mle);
3211                 spin_unlock(&dlm->master_lock);
3212         }
3213
3214         return res;
3215 }
3216
3217 static void dlm_clean_migration_mle(struct dlm_ctxt *dlm,
3218                                     struct dlm_master_list_entry *mle)
3219 {
3220         __dlm_mle_detach_hb_events(dlm, mle);
3221
3222         spin_lock(&mle->spinlock);
3223         __dlm_unlink_mle(dlm, mle);
3224         atomic_set(&mle->woken, 1);
3225         spin_unlock(&mle->spinlock);
3226
3227         wake_up(&mle->wq);
3228 }
3229
3230 static void dlm_clean_block_mle(struct dlm_ctxt *dlm,
3231                                 struct dlm_master_list_entry *mle, u8 dead_node)
3232 {
3233         int bit;
3234
3235         BUG_ON(mle->type != DLM_MLE_BLOCK);
3236
3237         spin_lock(&mle->spinlock);
3238         bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
3239         if (bit != dead_node) {
3240                 mlog(0, "mle found, but dead node %u would not have been "
3241                      "master\n", dead_node);
3242                 spin_unlock(&mle->spinlock);
3243         } else {
3244                 /* Must drop the refcount by one since the assert_master will
3245                  * never arrive. This may result in the mle being unlinked and
3246                  * freed, but there may still be a process waiting in the
3247                  * dlmlock path which is fine. */
3248                 mlog(0, "node %u was expected master\n", dead_node);
3249                 atomic_set(&mle->woken, 1);
3250                 spin_unlock(&mle->spinlock);
3251                 wake_up(&mle->wq);
3252
3253                 /* Do not need events any longer, so detach from heartbeat */
3254                 __dlm_mle_detach_hb_events(dlm, mle);
3255                 __dlm_put_mle(mle);
3256         }
3257 }
3258
3259 void dlm_clean_master_list(struct dlm_ctxt *dlm, u8 dead_node)
3260 {
3261         struct dlm_master_list_entry *mle;
3262         struct dlm_lock_resource *res;
3263         struct hlist_head *bucket;
3264         struct hlist_node *tmp;
3265         unsigned int i;
3266
3267         mlog(0, "dlm=%s, dead node=%u\n", dlm->name, dead_node);
3268 top:
3269         assert_spin_locked(&dlm->spinlock);
3270
3271         /* clean the master list */
3272         spin_lock(&dlm->master_lock);
3273         for (i = 0; i < DLM_HASH_BUCKETS; i++) {
3274                 bucket = dlm_master_hash(dlm, i);
3275                 hlist_for_each_entry_safe(mle, tmp, bucket, master_hash_node) {
3276                         BUG_ON(mle->type != DLM_MLE_BLOCK &&
3277                                mle->type != DLM_MLE_MASTER &&
3278                                mle->type != DLM_MLE_MIGRATION);
3279
3280                         /* MASTER mles are initiated locally. The waiting
3281                          * process will notice the node map change shortly.
3282                          * Let that happen as normal. */
3283                         if (mle->type == DLM_MLE_MASTER)
3284                                 continue;
3285
3286                         /* BLOCK mles are initiated by other nodes. Need to
3287                          * clean up if the dead node would have been the
3288                          * master. */
3289                         if (mle->type == DLM_MLE_BLOCK) {
3290                                 dlm_clean_block_mle(dlm, mle, dead_node);
3291                                 continue;
3292                         }
3293
3294                         /* Everything else is a MIGRATION mle */
3295
3296                         /* The rule for MIGRATION mles is that the master
3297                          * becomes UNKNOWN if *either* the original or the new
3298                          * master dies. All UNKNOWN lockres' are sent to
3299                          * whichever node becomes the recovery master. The new
3300                          * master is responsible for determining if there is
3301                          * still a master for this lockres, or if he needs to
3302                          * take over mastery. Either way, this node should
3303                          * expect another message to resolve this. */
3304
3305                         if (mle->master != dead_node &&
3306                             mle->new_master != dead_node)
3307                                 continue;
3308
3309                         /* If we have reached this point, this mle needs to be
3310                          * removed from the list and freed. */
3311                         dlm_clean_migration_mle(dlm, mle);
3312
3313                         mlog(0, "%s: node %u died during migration from "
3314                              "%u to %u!\n", dlm->name, dead_node, mle->master,
3315                              mle->new_master);
3316
3317                         /* If we find a lockres associated with the mle, we've
3318                          * hit this rare case that messes up our lock ordering.
3319                          * If so, we need to drop the master lock so that we can
3320                          * take the lockres lock, meaning that we will have to
3321                          * restart from the head of list. */
3322                         res = dlm_reset_mleres_owner(dlm, mle);
3323                         if (res)
3324                                 /* restart */
3325                                 goto top;
3326
3327                         /* This may be the last reference */
3328                         __dlm_put_mle(mle);
3329                 }
3330         }
3331         spin_unlock(&dlm->master_lock);
3332 }
3333
3334 int dlm_finish_migration(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
3335                          u8 old_master)
3336 {
3337         struct dlm_node_iter iter;
3338         int ret = 0;
3339
3340         spin_lock(&dlm->spinlock);
3341         dlm_node_iter_init(dlm->domain_map, &iter);
3342         clear_bit(old_master, iter.node_map);
3343         clear_bit(dlm->node_num, iter.node_map);
3344         spin_unlock(&dlm->spinlock);
3345
3346         /* ownership of the lockres is changing.  account for the
3347          * mastery reference here since old_master will briefly have
3348          * a reference after the migration completes */
3349         spin_lock(&res->spinlock);
3350         dlm_lockres_set_refmap_bit(dlm, res, old_master);
3351         spin_unlock(&res->spinlock);
3352
3353         mlog(0, "now time to do a migrate request to other nodes\n");
3354         ret = dlm_do_migrate_request(dlm, res, old_master,
3355                                      dlm->node_num, &iter);
3356         if (ret < 0) {
3357                 mlog_errno(ret);
3358                 goto leave;
3359         }
3360
3361         mlog(0, "doing assert master of %.*s to all except the original node\n",
3362              res->lockname.len, res->lockname.name);
3363         /* this call now finishes out the nodemap
3364          * even if one or more nodes die */
3365         ret = dlm_do_assert_master(dlm, res, iter.node_map,
3366                                    DLM_ASSERT_MASTER_FINISH_MIGRATION);
3367         if (ret < 0) {
3368                 /* no longer need to retry.  all living nodes contacted. */
3369                 mlog_errno(ret);
3370                 ret = 0;
3371         }
3372
3373         memset(iter.node_map, 0, sizeof(iter.node_map));
3374         set_bit(old_master, iter.node_map);
3375         mlog(0, "doing assert master of %.*s back to %u\n",
3376              res->lockname.len, res->lockname.name, old_master);
3377         ret = dlm_do_assert_master(dlm, res, iter.node_map,
3378                                    DLM_ASSERT_MASTER_FINISH_MIGRATION);
3379         if (ret < 0) {
3380                 mlog(0, "assert master to original master failed "
3381                      "with %d.\n", ret);
3382                 /* the only nonzero status here would be because of
3383                  * a dead original node.  we're done. */
3384                 ret = 0;
3385         }
3386
3387         /* all done, set the owner, clear the flag */
3388         spin_lock(&res->spinlock);
3389         dlm_set_lockres_owner(dlm, res, dlm->node_num);
3390         res->state &= ~DLM_LOCK_RES_MIGRATING;
3391         spin_unlock(&res->spinlock);
3392         /* re-dirty it on the new master */
3393         dlm_kick_thread(dlm, res);
3394         wake_up(&res->wq);
3395 leave:
3396         return ret;
3397 }
3398
3399 /*
3400  * LOCKRES AST REFCOUNT
3401  * this is integral to migration
3402  */
3403
3404 /* for future intent to call an ast, reserve one ahead of time.
3405  * this should be called only after waiting on the lockres
3406  * with dlm_wait_on_lockres, and while still holding the
3407  * spinlock after the call. */
3408 void __dlm_lockres_reserve_ast(struct dlm_lock_resource *res)
3409 {
3410         assert_spin_locked(&res->spinlock);
3411         if (res->state & DLM_LOCK_RES_MIGRATING) {
3412                 __dlm_print_one_lock_resource(res);
3413         }
3414         BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
3415
3416         atomic_inc(&res->asts_reserved);
3417 }
3418
3419 /*
3420  * used to drop the reserved ast, either because it went unused,
3421  * or because the ast/bast was actually called.
3422  *
3423  * also, if there is a pending migration on this lockres,
3424  * and this was the last pending ast on the lockres,
3425  * atomically set the MIGRATING flag before we drop the lock.
3426  * this is how we ensure that migration can proceed with no
3427  * asts in progress.  note that it is ok if the state of the
3428  * queues is such that a lock should be granted in the future
3429  * or that a bast should be fired, because the new master will
3430  * shuffle the lists on this lockres as soon as it is migrated.
3431  */
3432 void dlm_lockres_release_ast(struct dlm_ctxt *dlm,
3433                              struct dlm_lock_resource *res)
3434 {
3435         if (!atomic_dec_and_lock(&res->asts_reserved, &res->spinlock))
3436                 return;
3437
3438         if (!res->migration_pending) {
3439                 spin_unlock(&res->spinlock);
3440                 return;
3441         }
3442
3443         BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
3444         res->migration_pending = 0;
3445         res->state |= DLM_LOCK_RES_MIGRATING;
3446         spin_unlock(&res->spinlock);
3447         wake_up(&res->wq);
3448         wake_up(&dlm->migration_wq);
3449 }
3450
3451 void dlm_force_free_mles(struct dlm_ctxt *dlm)
3452 {
3453         int i;
3454         struct hlist_head *bucket;
3455         struct dlm_master_list_entry *mle;
3456         struct hlist_node *tmp;
3457
3458         /*
3459          * We notified all other nodes that we are exiting the domain and
3460          * marked the dlm state to DLM_CTXT_LEAVING. If any mles are still
3461          * around we force free them and wake any processes that are waiting
3462          * on the mles
3463          */
3464         spin_lock(&dlm->spinlock);
3465         spin_lock(&dlm->master_lock);
3466
3467         BUG_ON(dlm->dlm_state != DLM_CTXT_LEAVING);
3468         BUG_ON((find_next_bit(dlm->domain_map, O2NM_MAX_NODES, 0) < O2NM_MAX_NODES));
3469
3470         for (i = 0; i < DLM_HASH_BUCKETS; i++) {
3471                 bucket = dlm_master_hash(dlm, i);
3472                 hlist_for_each_entry_safe(mle, tmp, bucket, master_hash_node) {
3473                         if (mle->type != DLM_MLE_BLOCK) {
3474                                 mlog(ML_ERROR, "bad mle: %p\n", mle);
3475                                 dlm_print_one_mle(mle);
3476                         }
3477                         atomic_set(&mle->woken, 1);
3478                         wake_up(&mle->wq);
3479
3480                         __dlm_unlink_mle(dlm, mle);
3481                         __dlm_mle_detach_hb_events(dlm, mle);
3482                         __dlm_put_mle(mle);
3483                 }
3484         }
3485         spin_unlock(&dlm->master_lock);
3486         spin_unlock(&dlm->spinlock);
3487 }