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TOMOYO Linux Cross Reference
Linux/fs/ocfs2/dlm/dlmthread.c

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  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 }
830 

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