fs/ocfs2/dlm/dlmthread.c

   1 /* -*- mode: c; c-basic-offset: 8; -*-
   2  * vim: noexpandtab sw=8 ts=8 sts=0:
   3  *
   4  * dlmthread.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/highmem.h>
  32 #include <linux/init.h>
  33 #include <linux/sysctl.h>
  34 #include <linux/random.h>
  35 #include <linux/blkdev.h>
  36 #include <linux/socket.h>
  37 #include <linux/inet.h>
  38 #include <linux/timer.h>
  39 #include <linux/kthread.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
  51 #define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_THREAD)
  52 #include "cluster/masklog.h"
  53
  54 static int dlm_thread(void *data);
  55 static void dlm_flush_asts(struct dlm_ctxt *dlm);
  56
  57 #define dlm_lock_is_remote(dlm, lock)     ((lock)->ml.node != (dlm)->node_num)
  58
  59 /* will exit holding res->spinlock, but may drop in function */
  60 /* waits until flags are cleared on res->state */
  61 void __dlm_wait_on_lockres_flags(struct dlm_lock_resource *res, int flags)
  62 {
  63         DECLARE_WAITQUEUE(wait, current);
  64
  65         assert_spin_locked(&res->spinlock);
  66
  67         add_wait_queue(&res->wq, &wait);
  68 repeat:
  69         set_current_state(TASK_UNINTERRUPTIBLE);
  70         if (res->state & flags) {
  71                 spin_unlock(&res->spinlock);
  72                 schedule();
  73                 spin_lock(&res->spinlock);
  74                 goto repeat;
  75         }
  76         remove_wait_queue(&res->wq, &wait);
  77         __set_current_state(TASK_RUNNING);
  78 }
  79
  80 int __dlm_lockres_has_locks(struct dlm_lock_resource *res)
  81 {
  82         if (list_empty(&res->granted) &&
  83             list_empty(&res->converting) &&
  84             list_empty(&res->blocked))
  85                 return 0;
  86         return 1;
  87 }
  88
  89 /* "unused": the lockres has no locks, is not on the dirty list,
  90  * has no inflight locks (in the gap between mastery and acquiring
  91  * the first lock), and has no bits in its refmap.
  92  * truly ready to be freed. */
  93 int __dlm_lockres_unused(struct dlm_lock_resource *res)
  94 {
  95         int bit;
  96
  97         assert_spin_locked(&res->spinlock);
  98
  99         if (__dlm_lockres_has_locks(res))
 100                 return 0;
 101
 102         /* Locks are in the process of being created */
 103         if (res->inflight_locks)
 104                 return 0;
 105
 106         if (!list_empty(&res->dirty) || res->state & DLM_LOCK_RES_DIRTY)
 107                 return 0;
 108
 109         if (res->state & (DLM_LOCK_RES_RECOVERING|
 110                         DLM_LOCK_RES_RECOVERY_WAITING))
 111                 return 0;
 112
 113         /* Another node has this resource with this node as the master */
 114         bit = find_next_bit(res->refmap, O2NM_MAX_NODES, 0);
 115         if (bit < O2NM_MAX_NODES)
 116                 return 0;
 117
 118         return 1;
 119 }
 120
 121
 122 /* Call whenever you may have added or deleted something from one of
 123  * the lockres queue's. This will figure out whether it belongs on the
 124  * unused list or not and does the appropriate thing. */
 125 void __dlm_lockres_calc_usage(struct dlm_ctxt *dlm,
 126                               struct dlm_lock_resource *res)
 127 {
 128         assert_spin_locked(&dlm->spinlock);
 129         assert_spin_locked(&res->spinlock);
 130
 131         if (__dlm_lockres_unused(res)){
 132                 if (list_empty(&res->purge)) {
 133                         mlog(0, "%s: Adding res %.*s to purge list\n",
 134                              dlm->name, res->lockname.len, res->lockname.name);
 135
 136                         res->last_used = jiffies;
 137                         dlm_lockres_get(res);
 138                         list_add_tail(&res->purge, &dlm->purge_list);
 139                         dlm->purge_count++;
 140                 }
 141         } else if (!list_empty(&res->purge)) {
 142                 mlog(0, "%s: Removing res %.*s from purge list\n",
 143                      dlm->name, res->lockname.len, res->lockname.name);
 144
 145                 list_del_init(&res->purge);
 146                 dlm_lockres_put(res);
 147                 dlm->purge_count--;
 148         }
 149 }
 150
 151 void dlm_lockres_calc_usage(struct dlm_ctxt *dlm,
 152                             struct dlm_lock_resource *res)
 153 {
 154         spin_lock(&dlm->spinlock);
 155         spin_lock(&res->spinlock);
 156
 157         __dlm_lockres_calc_usage(dlm, res);
 158
 159         spin_unlock(&res->spinlock);
 160         spin_unlock(&dlm->spinlock);
 161 }
 162
 163 /*
 164  * Do the real purge work:
 165  *     unhash the lockres, and
 166  *     clear flag DLM_LOCK_RES_DROPPING_REF.
 167  * It requires dlm and lockres spinlock to be taken.
 168  */
 169 void __dlm_do_purge_lockres(struct dlm_ctxt *dlm,
 170                 struct dlm_lock_resource *res)
 171 {
 172         assert_spin_locked(&dlm->spinlock);
 173         assert_spin_locked(&res->spinlock);
 174
 175         if (!list_empty(&res->purge)) {
 176                 mlog(0, "%s: Removing res %.*s from purgelist\n",
 177                      dlm->name, res->lockname.len, res->lockname.name);
 178                 list_del_init(&res->purge);
 179                 dlm_lockres_put(res);
 180                 dlm->purge_count--;
 181         }
 182
 183         if (!__dlm_lockres_unused(res)) {
 184                 mlog(ML_ERROR, "%s: res %.*s in use after deref\n",
 185                      dlm->name, res->lockname.len, res->lockname.name);
 186                 __dlm_print_one_lock_resource(res);
 187                 BUG();
 188         }
 189
 190         __dlm_unhash_lockres(dlm, res);
 191
 192         spin_lock(&dlm->track_lock);
 193         if (!list_empty(&res->tracking))
 194                 list_del_init(&res->tracking);
 195         else {
 196                 mlog(ML_ERROR, "%s: Resource %.*s not on the Tracking list\n",
 197                      dlm->name, res->lockname.len, res->lockname.name);
 198                 __dlm_print_one_lock_resource(res);
 199         }
 200         spin_unlock(&dlm->track_lock);
 201
 202         /*
 203          * lockres is not in the hash now. drop the flag and wake up
 204          * any processes waiting in dlm_get_lock_resource.
 205          */
 206         res->state &= ~DLM_LOCK_RES_DROPPING_REF;
 207 }
 208
 209 static void dlm_purge_lockres(struct dlm_ctxt *dlm,
 210                              struct dlm_lock_resource *res)
 211 {
 212         int master;
 213         int ret = 0;
 214
 215         assert_spin_locked(&dlm->spinlock);
 216         assert_spin_locked(&res->spinlock);
 217
 218         master = (res->owner == dlm->node_num);
 219
 220         mlog(0, "%s: Purging res %.*s, master %d\n", dlm->name,
 221              res->lockname.len, res->lockname.name, master);
 222
 223         if (!master) {
 224                 if (res->state & DLM_LOCK_RES_DROPPING_REF) {
 225                         mlog(ML_NOTICE, "%s: res %.*s already in DLM_LOCK_RES_DROPPING_REF state\n",
 226                                 dlm->name, res->lockname.len, res->lockname.name);
 227                         spin_unlock(&res->spinlock);
 228                         return;
 229                 }
 230
 231                 res->state |= DLM_LOCK_RES_DROPPING_REF;
 232                 /* drop spinlock...  retake below */
 233                 spin_unlock(&res->spinlock);
 234                 spin_unlock(&dlm->spinlock);
 235
 236                 spin_lock(&res->spinlock);
 237                 /* This ensures that clear refmap is sent after the set */
 238                 __dlm_wait_on_lockres_flags(res, DLM_LOCK_RES_SETREF_INPROG);
 239                 spin_unlock(&res->spinlock);
 240
 241                 /* clear our bit from the master's refmap, ignore errors */
 242                 ret = dlm_drop_lockres_ref(dlm, res);
 243                 if (ret < 0) {
 244                         if (!dlm_is_host_down(ret))
 245                                 BUG();
 246                 }
 247                 spin_lock(&dlm->spinlock);
 248                 spin_lock(&res->spinlock);
 249         }
 250
 251         if (!list_empty(&res->purge)) {
 252                 mlog(0, "%s: Removing res %.*s from purgelist, master %d\n",
 253                      dlm->name, res->lockname.len, res->lockname.name, master);
 254                 list_del_init(&res->purge);
 255                 dlm_lockres_put(res);
 256                 dlm->purge_count--;
 257         }
 258
 259         if (!master && ret == DLM_DEREF_RESPONSE_INPROG) {
 260                 mlog(0, "%s: deref %.*s in progress\n",
 261                         dlm->name, res->lockname.len, res->lockname.name);
 262                 spin_unlock(&res->spinlock);
 263                 return;
 264         }
 265
 266         if (!__dlm_lockres_unused(res)) {
 267                 mlog(ML_ERROR, "%s: res %.*s in use after deref\n",
 268                      dlm->name, res->lockname.len, res->lockname.name);
 269                 __dlm_print_one_lock_resource(res);
 270                 BUG();
 271         }
 272
 273         __dlm_unhash_lockres(dlm, res);
 274
 275         spin_lock(&dlm->track_lock);
 276         if (!list_empty(&res->tracking))
 277                 list_del_init(&res->tracking);
 278         else {
 279                 mlog(ML_ERROR, "Resource %.*s not on the Tracking list\n",
 280                                 res->lockname.len, res->lockname.name);
 281                 __dlm_print_one_lock_resource(res);
 282         }
 283         spin_unlock(&dlm->track_lock);
 284
 285         /* lockres is not in the hash now.  drop the flag and wake up
 286          * any processes waiting in dlm_get_lock_resource. */
 287         if (!master) {
 288                 res->state &= ~DLM_LOCK_RES_DROPPING_REF;
 289                 spin_unlock(&res->spinlock);
 290                 wake_up(&res->wq);
 291         } else
 292                 spin_unlock(&res->spinlock);
 293 }
 294
 295 static void dlm_run_purge_list(struct dlm_ctxt *dlm,
 296                                int purge_now)
 297 {
 298         unsigned int run_max, unused;
 299         unsigned long purge_jiffies;
 300         struct dlm_lock_resource *lockres;
 301
 302         spin_lock(&dlm->spinlock);
 303         run_max = dlm->purge_count;
 304
 305         while(run_max && !list_empty(&dlm->purge_list)) {
 306                 run_max--;
 307
 308                 lockres = list_entry(dlm->purge_list.next,
 309                                      struct dlm_lock_resource, purge);
 310
 311                 spin_lock(&lockres->spinlock);
 312
 313                 purge_jiffies = lockres->last_used +
 314                         msecs_to_jiffies(DLM_PURGE_INTERVAL_MS);
 315
 316                 /* Make sure that we want to be processing this guy at
 317                  * this time. */
 318                 if (!purge_now && time_after(purge_jiffies, jiffies)) {
 319                         /* Since resources are added to the purge list
 320                          * in tail order, we can stop at the first
 321                          * unpurgable resource -- anyone added after
 322                          * him will have a greater last_used value */
 323                         spin_unlock(&lockres->spinlock);
 324                         break;
 325                 }
 326
 327                 /* Status of the lockres *might* change so double
 328                  * check. If the lockres is unused, holding the dlm
 329                  * spinlock will prevent people from getting and more
 330                  * refs on it. */
 331                 unused = __dlm_lockres_unused(lockres);
 332                 if (!unused ||
 333                     (lockres->state & DLM_LOCK_RES_MIGRATING) ||
 334                     (lockres->inflight_assert_workers != 0)) {
 335                         mlog(0, "%s: res %.*s is in use or being remastered, "
 336                              "used %d, state %d, assert master workers %u\n",
 337                              dlm->name, lockres->lockname.len,
 338                              lockres->lockname.name,
 339                              !unused, lockres->state,
 340                              lockres->inflight_assert_workers);
 341                         list_move_tail(&lockres->purge, &dlm->purge_list);
 342                         spin_unlock(&lockres->spinlock);
 343                         continue;
 344                 }
 345
 346                 dlm_lockres_get(lockres);
 347
 348                 dlm_purge_lockres(dlm, lockres);
 349
 350                 dlm_lockres_put(lockres);
 351
 352                 /* Avoid adding any scheduling latencies */
 353                 cond_resched_lock(&dlm->spinlock);
 354         }
 355
 356         spin_unlock(&dlm->spinlock);
 357 }
 358
 359 static void dlm_shuffle_lists(struct dlm_ctxt *dlm,
 360                               struct dlm_lock_resource *res)
 361 {
 362         struct dlm_lock *lock, *target;
 363         int can_grant = 1;
 364
 365         /*
 366          * Because this function is called with the lockres
 367          * spinlock, and because we know that it is not migrating/
 368          * recovering/in-progress, it is fine to reserve asts and
 369          * basts right before queueing them all throughout
 370          */
 371         assert_spin_locked(&dlm->ast_lock);
 372         assert_spin_locked(&res->spinlock);
 373         BUG_ON((res->state & (DLM_LOCK_RES_MIGRATING|
 374                               DLM_LOCK_RES_RECOVERING|
 375                               DLM_LOCK_RES_IN_PROGRESS)));
 376
 377 converting:
 378         if (list_empty(&res->converting))
 379                 goto blocked;
 380         mlog(0, "%s: res %.*s has locks on the convert queue\n", dlm->name,
 381              res->lockname.len, res->lockname.name);
 382
 383         target = list_entry(res->converting.next, struct dlm_lock, list);
 384         if (target->ml.convert_type == LKM_IVMODE) {
 385                 mlog(ML_ERROR, "%s: res %.*s converting lock to invalid mode\n",
 386                      dlm->name, res->lockname.len, res->lockname.name);
 387                 BUG();
 388         }
 389         list_for_each_entry(lock, &res->granted, list) {
 390                 if (lock==target)
 391                         continue;
 392                 if (!dlm_lock_compatible(lock->ml.type,
 393                                          target->ml.convert_type)) {
 394                         can_grant = 0;
 395                         /* queue the BAST if not already */
 396                         if (lock->ml.highest_blocked == LKM_IVMODE) {
 397                                 __dlm_lockres_reserve_ast(res);
 398                                 __dlm_queue_bast(dlm, lock);
 399                         }
 400                         /* update the highest_blocked if needed */
 401                         if (lock->ml.highest_blocked < target->ml.convert_type)
 402                                 lock->ml.highest_blocked =
 403                                         target->ml.convert_type;
 404                 }
 405         }
 406
 407         list_for_each_entry(lock, &res->converting, list) {
 408                 if (lock==target)
 409                         continue;
 410                 if (!dlm_lock_compatible(lock->ml.type,
 411                                          target->ml.convert_type)) {
 412                         can_grant = 0;
 413                         if (lock->ml.highest_blocked == LKM_IVMODE) {
 414                                 __dlm_lockres_reserve_ast(res);
 415                                 __dlm_queue_bast(dlm, lock);
 416                         }
 417                         if (lock->ml.highest_blocked < target->ml.convert_type)
 418                                 lock->ml.highest_blocked =
 419                                         target->ml.convert_type;
 420                 }
 421         }
 422
 423         /* we can convert the lock */
 424         if (can_grant) {
 425                 spin_lock(&target->spinlock);
 426                 BUG_ON(target->ml.highest_blocked != LKM_IVMODE);
 427
 428                 mlog(0, "%s: res %.*s, AST for Converting lock %u:%llu, type "
 429                      "%d => %d, node %u\n", dlm->name, res->lockname.len,
 430                      res->lockname.name,
 431                      dlm_get_lock_cookie_node(be64_to_cpu(target->ml.cookie)),
 432                      dlm_get_lock_cookie_seq(be64_to_cpu(target->ml.cookie)),
 433                      target->ml.type,
 434                      target->ml.convert_type, target->ml.node);
 435
 436                 target->ml.type = target->ml.convert_type;
 437                 target->ml.convert_type = LKM_IVMODE;
 438                 list_move_tail(&target->list, &res->granted);
 439
 440                 BUG_ON(!target->lksb);
 441                 target->lksb->status = DLM_NORMAL;
 442
 443                 spin_unlock(&target->spinlock);
 444
 445                 __dlm_lockres_reserve_ast(res);
 446                 __dlm_queue_ast(dlm, target);
 447                 /* go back and check for more */
 448                 goto converting;
 449         }
 450
 451 blocked:
 452         if (list_empty(&res->blocked))
 453                 goto leave;
 454         target = list_entry(res->blocked.next, struct dlm_lock, list);
 455
 456         list_for_each_entry(lock, &res->granted, list) {
 457                 if (lock==target)
 458                         continue;
 459                 if (!dlm_lock_compatible(lock->ml.type, target->ml.type)) {
 460                         can_grant = 0;
 461                         if (lock->ml.highest_blocked == LKM_IVMODE) {
 462                                 __dlm_lockres_reserve_ast(res);
 463                                 __dlm_queue_bast(dlm, lock);
 464                         }
 465                         if (lock->ml.highest_blocked < target->ml.type)
 466                                 lock->ml.highest_blocked = target->ml.type;
 467                 }
 468         }
 469
 470         list_for_each_entry(lock, &res->converting, list) {
 471                 if (lock==target)
 472                         continue;
 473                 if (!dlm_lock_compatible(lock->ml.type, target->ml.type)) {
 474                         can_grant = 0;
 475                         if (lock->ml.highest_blocked == LKM_IVMODE) {
 476                                 __dlm_lockres_reserve_ast(res);
 477                                 __dlm_queue_bast(dlm, lock);
 478                         }
 479                         if (lock->ml.highest_blocked < target->ml.type)
 480                                 lock->ml.highest_blocked = target->ml.type;
 481                 }
 482         }
 483
 484         /* we can grant the blocked lock (only
 485          * possible if converting list empty) */
 486         if (can_grant) {
 487                 spin_lock(&target->spinlock);
 488                 BUG_ON(target->ml.highest_blocked != LKM_IVMODE);
 489
 490                 mlog(0, "%s: res %.*s, AST for Blocked lock %u:%llu, type %d, "
 491                      "node %u\n", dlm->name, res->lockname.len,
 492                      res->lockname.name,
 493                      dlm_get_lock_cookie_node(be64_to_cpu(target->ml.cookie)),
 494                      dlm_get_lock_cookie_seq(be64_to_cpu(target->ml.cookie)),
 495                      target->ml.type, target->ml.node);
 496
 497                 /* target->ml.type is already correct */
 498                 list_move_tail(&target->list, &res->granted);
 499
 500                 BUG_ON(!target->lksb);
 501                 target->lksb->status = DLM_NORMAL;
 502
 503                 spin_unlock(&target->spinlock);
 504
 505                 __dlm_lockres_reserve_ast(res);
 506                 __dlm_queue_ast(dlm, target);
 507                 /* go back and check for more */
 508                 goto converting;
 509         }
 510
 511 leave:
 512         return;
 513 }
 514
 515 /* must have NO locks when calling this with res !=NULL * */
 516 void dlm_kick_thread(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
 517 {
 518         if (res) {
 519                 spin_lock(&dlm->spinlock);
 520                 spin_lock(&res->spinlock);
 521                 __dlm_dirty_lockres(dlm, res);
 522                 spin_unlock(&res->spinlock);
 523                 spin_unlock(&dlm->spinlock);
 524         }
 525         wake_up(&dlm->dlm_thread_wq);
 526 }
 527
 528 void __dlm_dirty_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
 529 {
 530         assert_spin_locked(&dlm->spinlock);
 531         assert_spin_locked(&res->spinlock);
 532
 533         /* don't shuffle secondary queues */
 534         if ((res->owner == dlm->node_num)) {
 535                 if (res->state & (DLM_LOCK_RES_MIGRATING |
 536                                   DLM_LOCK_RES_BLOCK_DIRTY))
 537                     return;
 538
 539                 if (list_empty(&res->dirty)) {
 540                         /* ref for dirty_list */
 541                         dlm_lockres_get(res);
 542                         list_add_tail(&res->dirty, &dlm->dirty_list);
 543                         res->state |= DLM_LOCK_RES_DIRTY;
 544                 }
 545         }
 546
 547         mlog(0, "%s: res %.*s\n", dlm->name, res->lockname.len,
 548              res->lockname.name);
 549 }
 550
 551
 552 /* Launch the NM thread for the mounted volume */
 553 int dlm_launch_thread(struct dlm_ctxt *dlm)
 554 {
 555         mlog(0, "Starting dlm_thread...\n");
 556
 557         dlm->dlm_thread_task = kthread_run(dlm_thread, dlm, "dlm-%s",
 558                         dlm->name);
 559         if (IS_ERR(dlm->dlm_thread_task)) {
 560                 mlog_errno(PTR_ERR(dlm->dlm_thread_task));
 561                 dlm->dlm_thread_task = NULL;
 562                 return -EINVAL;
 563         }
 564
 565         return 0;
 566 }
 567
 568 void dlm_complete_thread(struct dlm_ctxt *dlm)
 569 {
 570         if (dlm->dlm_thread_task) {
 571                 mlog(ML_KTHREAD, "Waiting for dlm thread to exit\n");
 572                 kthread_stop(dlm->dlm_thread_task);
 573                 dlm->dlm_thread_task = NULL;
 574         }
 575 }
 576
 577 static int dlm_dirty_list_empty(struct dlm_ctxt *dlm)
 578 {
 579         int empty;
 580
 581         spin_lock(&dlm->spinlock);
 582         empty = list_empty(&dlm->dirty_list);
 583         spin_unlock(&dlm->spinlock);
 584
 585         return empty;
 586 }
 587
 588 static void dlm_flush_asts(struct dlm_ctxt *dlm)
 589 {
 590         int ret;
 591         struct dlm_lock *lock;
 592         struct dlm_lock_resource *res;
 593         u8 hi;
 594
 595         spin_lock(&dlm->ast_lock);
 596         while (!list_empty(&dlm->pending_asts)) {
 597                 lock = list_entry(dlm->pending_asts.next,
 598                                   struct dlm_lock, ast_list);
 599                 /* get an extra ref on lock */
 600                 dlm_lock_get(lock);
 601                 res = lock->lockres;
 602                 mlog(0, "%s: res %.*s, Flush AST for lock %u:%llu, type %d, "
 603                      "node %u\n", dlm->name, res->lockname.len,
 604                      res->lockname.name,
 605                      dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
 606                      dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
 607                      lock->ml.type, lock->ml.node);
 608
 609                 BUG_ON(!lock->ast_pending);
 610
 611                 /* remove from list (including ref) */
 612                 list_del_init(&lock->ast_list);
 613                 dlm_lock_put(lock);
 614                 spin_unlock(&dlm->ast_lock);
 615
 616                 if (lock->ml.node != dlm->node_num) {
 617                         ret = dlm_do_remote_ast(dlm, res, lock);
 618                         if (ret < 0)
 619                                 mlog_errno(ret);
 620                 } else
 621                         dlm_do_local_ast(dlm, res, lock);
 622
 623                 spin_lock(&dlm->ast_lock);
 624
 625                 /* possible that another ast was queued while
 626                  * we were delivering the last one */
 627                 if (!list_empty(&lock->ast_list)) {
 628                         mlog(0, "%s: res %.*s, AST queued while flushing last "
 629                              "one\n", dlm->name, res->lockname.len,
 630                              res->lockname.name);
 631                 } else
 632                         lock->ast_pending = 0;
 633
 634                 /* drop the extra ref.
 635                  * this may drop it completely. */
 636                 dlm_lock_put(lock);
 637                 dlm_lockres_release_ast(dlm, res);
 638         }
 639
 640         while (!list_empty(&dlm->pending_basts)) {
 641                 lock = list_entry(dlm->pending_basts.next,
 642                                   struct dlm_lock, bast_list);
 643                 /* get an extra ref on lock */
 644                 dlm_lock_get(lock);
 645                 res = lock->lockres;
 646
 647                 BUG_ON(!lock->bast_pending);
 648
 649                 /* get the highest blocked lock, and reset */
 650                 spin_lock(&lock->spinlock);
 651                 BUG_ON(lock->ml.highest_blocked <= LKM_IVMODE);
 652                 hi = lock->ml.highest_blocked;
 653                 lock->ml.highest_blocked = LKM_IVMODE;
 654                 spin_unlock(&lock->spinlock);
 655
 656                 /* remove from list (including ref) */
 657                 list_del_init(&lock->bast_list);
 658                 dlm_lock_put(lock);
 659                 spin_unlock(&dlm->ast_lock);
 660
 661                 mlog(0, "%s: res %.*s, Flush BAST for lock %u:%llu, "
 662                      "blocked %d, node %u\n",
 663                      dlm->name, res->lockname.len, res->lockname.name,
 664                      dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
 665                      dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
 666                      hi, lock->ml.node);
 667
 668                 if (lock->ml.node != dlm->node_num) {
 669                         ret = dlm_send_proxy_bast(dlm, res, lock, hi);
 670                         if (ret < 0)
 671                                 mlog_errno(ret);
 672                 } else
 673                         dlm_do_local_bast(dlm, res, lock, hi);
 674
 675                 spin_lock(&dlm->ast_lock);
 676
 677                 /* possible that another bast was queued while
 678                  * we were delivering the last one */
 679                 if (!list_empty(&lock->bast_list)) {
 680                         mlog(0, "%s: res %.*s, BAST queued while flushing last "
 681                              "one\n", dlm->name, res->lockname.len,
 682                              res->lockname.name);
 683                 } else
 684                         lock->bast_pending = 0;
 685
 686                 /* drop the extra ref.
 687                  * this may drop it completely. */
 688                 dlm_lock_put(lock);
 689                 dlm_lockres_release_ast(dlm, res);
 690         }
 691         wake_up(&dlm->ast_wq);
 692         spin_unlock(&dlm->ast_lock);
 693 }
 694
 695
 696 #define DLM_THREAD_TIMEOUT_MS (4 * 1000)
 697 #define DLM_THREAD_MAX_DIRTY  100
 698 #define DLM_THREAD_MAX_ASTS   10
 699
 700 static int dlm_thread(void *data)
 701 {
 702         struct dlm_lock_resource *res;
 703         struct dlm_ctxt *dlm = data;
 704         unsigned long timeout = msecs_to_jiffies(DLM_THREAD_TIMEOUT_MS);
 705
 706         mlog(0, "dlm thread running for %s...\n", dlm->name);
 707
 708         while (!kthread_should_stop()) {
 709                 int n = DLM_THREAD_MAX_DIRTY;
 710
 711                 /* dlm_shutting_down is very point-in-time, but that
 712                  * doesn't matter as we'll just loop back around if we
 713                  * get false on the leading edge of a state
 714                  * transition. */
 715                 dlm_run_purge_list(dlm, dlm_shutting_down(dlm));
 716
 717                 /* We really don't want to hold dlm->spinlock while
 718                  * calling dlm_shuffle_lists on each lockres that
 719                  * needs to have its queues adjusted and AST/BASTs
 720                  * run.  So let's pull each entry off the dirty_list
 721                  * and drop dlm->spinlock ASAP.  Once off the list,
 722                  * res->spinlock needs to be taken again to protect
 723                  * the queues while calling dlm_shuffle_lists.  */
 724                 spin_lock(&dlm->spinlock);
 725                 while (!list_empty(&dlm->dirty_list)) {
 726                         int delay = 0;
 727                         res = list_entry(dlm->dirty_list.next,
 728                                          struct dlm_lock_resource, dirty);
 729
 730                         /* peel a lockres off, remove it from the list,
 731                          * unset the dirty flag and drop the dlm lock */
 732                         BUG_ON(!res);
 733                         dlm_lockres_get(res);
 734
 735                         spin_lock(&res->spinlock);
 736                         /* We clear the DLM_LOCK_RES_DIRTY state once we shuffle lists below */
 737                         list_del_init(&res->dirty);
 738                         spin_unlock(&res->spinlock);
 739                         spin_unlock(&dlm->spinlock);
 740                         /* Drop dirty_list ref */
 741                         dlm_lockres_put(res);
 742
 743                         /* lockres can be re-dirtied/re-added to the
 744                          * dirty_list in this gap, but that is ok */
 745
 746                         spin_lock(&dlm->ast_lock);
 747                         spin_lock(&res->spinlock);
 748                         if (res->owner != dlm->node_num) {
 749                                 __dlm_print_one_lock_resource(res);
 750                                 mlog(ML_ERROR, "%s: inprog %d, mig %d, reco %d,"
 751                                      " dirty %d\n", dlm->name,
 752                                      !!(res->state & DLM_LOCK_RES_IN_PROGRESS),
 753                                      !!(res->state & DLM_LOCK_RES_MIGRATING),
 754                                      !!(res->state & DLM_LOCK_RES_RECOVERING),
 755                                      !!(res->state & DLM_LOCK_RES_DIRTY));
 756                         }
 757                         BUG_ON(res->owner != dlm->node_num);
 758
 759                         /* it is now ok to move lockreses in these states
 760                          * to the dirty list, assuming that they will only be
 761                          * dirty for a short while. */
 762                         BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
 763                         if (res->state & (DLM_LOCK_RES_IN_PROGRESS |
 764                                           DLM_LOCK_RES_RECOVERING |
 765                                           DLM_LOCK_RES_RECOVERY_WAITING)) {
 766                                 /* move it to the tail and keep going */
 767                                 res->state &= ~DLM_LOCK_RES_DIRTY;
 768                                 spin_unlock(&res->spinlock);
 769                                 spin_unlock(&dlm->ast_lock);
 770                                 mlog(0, "%s: res %.*s, inprogress, delay list "
 771                                      "shuffle, state %d\n", dlm->name,
 772                                      res->lockname.len, res->lockname.name,
 773                                      res->state);
 774                                 delay = 1;
 775                                 goto in_progress;
 776                         }
 777
 778                         /* at this point the lockres is not migrating/
 779                          * recovering/in-progress.  we have the lockres
 780                          * spinlock and do NOT have the dlm lock.
 781                          * safe to reserve/queue asts and run the lists. */
 782
 783                         /* called while holding lockres lock */
 784                         dlm_shuffle_lists(dlm, res);
 785                         res->state &= ~DLM_LOCK_RES_DIRTY;
 786                         spin_unlock(&res->spinlock);
 787                         spin_unlock(&dlm->ast_lock);
 788
 789                         dlm_lockres_calc_usage(dlm, res);
 790
 791 in_progress:
 792
 793                         spin_lock(&dlm->spinlock);
 794                         /* if the lock was in-progress, stick
 795                          * it on the back of the list */
 796                         if (delay) {
 797                                 spin_lock(&res->spinlock);
 798                                 __dlm_dirty_lockres(dlm, res);
 799                                 spin_unlock(&res->spinlock);
 800                         }
 801                         dlm_lockres_put(res);
 802
 803                         /* unlikely, but we may need to give time to
 804                          * other tasks */
 805                         if (!--n) {
 806                                 mlog(0, "%s: Throttling dlm thread\n",
 807                                      dlm->name);
 808                                 break;
 809                         }
 810                 }
 811
 812                 spin_unlock(&dlm->spinlock);
 813                 dlm_flush_asts(dlm);
 814
 815                 /* yield and continue right away if there is more work to do */
 816                 if (!n) {
 817                         cond_resched();
 818                         continue;
 819                 }
 820
 821                 wait_event_interruptible_timeout(dlm->dlm_thread_wq,
 822                                                  !dlm_dirty_list_empty(dlm) ||
 823                                                  kthread_should_stop(),
 824                                                  timeout);
 825         }
 826
 827         mlog(0, "quitting DLM thread\n");
 828         return 0;
 829 }