Merge branch 'bjorn-initcall-cleanup' into release
[linux-2.6] / 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/slab.h>
32 #include <linux/highmem.h>
33 #include <linux/utsname.h>
34 #include <linux/init.h>
35 #include <linux/sysctl.h>
36 #include <linux/random.h>
37 #include <linux/blkdev.h>
38 #include <linux/socket.h>
39 #include <linux/inet.h>
40 #include <linux/timer.h>
41 #include <linux/kthread.h>
42 #include <linux/delay.h>
43
44
45 #include "cluster/heartbeat.h"
46 #include "cluster/nodemanager.h"
47 #include "cluster/tcp.h"
48
49 #include "dlmapi.h"
50 #include "dlmcommon.h"
51 #include "dlmdomain.h"
52
53 #define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_THREAD)
54 #include "cluster/masklog.h"
55
56 static int dlm_thread(void *data);
57 static void dlm_flush_asts(struct dlm_ctxt *dlm);
58
59 #define dlm_lock_is_remote(dlm, lock)     ((lock)->ml.node != (dlm)->node_num)
60
61 /* will exit holding res->spinlock, but may drop in function */
62 /* waits until flags are cleared on res->state */
63 void __dlm_wait_on_lockres_flags(struct dlm_lock_resource *res, int flags)
64 {
65         DECLARE_WAITQUEUE(wait, current);
66
67         assert_spin_locked(&res->spinlock);
68
69         add_wait_queue(&res->wq, &wait);
70 repeat:
71         set_current_state(TASK_UNINTERRUPTIBLE);
72         if (res->state & flags) {
73                 spin_unlock(&res->spinlock);
74                 schedule();
75                 spin_lock(&res->spinlock);
76                 goto repeat;
77         }
78         remove_wait_queue(&res->wq, &wait);
79         __set_current_state(TASK_RUNNING);
80 }
81
82 int __dlm_lockres_has_locks(struct dlm_lock_resource *res)
83 {
84         if (list_empty(&res->granted) &&
85             list_empty(&res->converting) &&
86             list_empty(&res->blocked))
87                 return 0;
88         return 1;
89 }
90
91 /* "unused": the lockres has no locks, is not on the dirty list,
92  * has no inflight locks (in the gap between mastery and acquiring
93  * the first lock), and has no bits in its refmap.
94  * truly ready to be freed. */
95 int __dlm_lockres_unused(struct dlm_lock_resource *res)
96 {
97         if (!__dlm_lockres_has_locks(res) &&
98             (list_empty(&res->dirty) && !(res->state & DLM_LOCK_RES_DIRTY))) {
99                 /* try not to scan the bitmap unless the first two
100                  * conditions are already true */
101                 int bit = find_next_bit(res->refmap, O2NM_MAX_NODES, 0);
102                 if (bit >= O2NM_MAX_NODES) {
103                         /* since the bit for dlm->node_num is not
104                          * set, inflight_locks better be zero */
105                         BUG_ON(res->inflight_locks != 0);
106                         return 1;
107                 }
108         }
109         return 0;
110 }
111
112
113 /* Call whenever you may have added or deleted something from one of
114  * the lockres queue's. This will figure out whether it belongs on the
115  * unused list or not and does the appropriate thing. */
116 void __dlm_lockres_calc_usage(struct dlm_ctxt *dlm,
117                               struct dlm_lock_resource *res)
118 {
119         mlog_entry("%.*s\n", res->lockname.len, res->lockname.name);
120
121         assert_spin_locked(&dlm->spinlock);
122         assert_spin_locked(&res->spinlock);
123
124         if (__dlm_lockres_unused(res)){
125                 if (list_empty(&res->purge)) {
126                         mlog(0, "putting lockres %.*s:%p onto purge list\n",
127                              res->lockname.len, res->lockname.name, res);
128
129                         res->last_used = jiffies;
130                         dlm_lockres_get(res);
131                         list_add_tail(&res->purge, &dlm->purge_list);
132                         dlm->purge_count++;
133                 }
134         } else if (!list_empty(&res->purge)) {
135                 mlog(0, "removing lockres %.*s:%p from purge list, owner=%u\n",
136                      res->lockname.len, res->lockname.name, res, res->owner);
137
138                 list_del_init(&res->purge);
139                 dlm_lockres_put(res);
140                 dlm->purge_count--;
141         }
142 }
143
144 void dlm_lockres_calc_usage(struct dlm_ctxt *dlm,
145                             struct dlm_lock_resource *res)
146 {
147         mlog_entry("%.*s\n", res->lockname.len, res->lockname.name);
148         spin_lock(&dlm->spinlock);
149         spin_lock(&res->spinlock);
150
151         __dlm_lockres_calc_usage(dlm, res);
152
153         spin_unlock(&res->spinlock);
154         spin_unlock(&dlm->spinlock);
155 }
156
157 static int dlm_purge_lockres(struct dlm_ctxt *dlm,
158                              struct dlm_lock_resource *res)
159 {
160         int master;
161         int ret = 0;
162
163         spin_lock(&res->spinlock);
164         if (!__dlm_lockres_unused(res)) {
165                 spin_unlock(&res->spinlock);
166                 mlog(0, "%s:%.*s: tried to purge but not unused\n",
167                      dlm->name, res->lockname.len, res->lockname.name);
168                 return -ENOTEMPTY;
169         }
170         master = (res->owner == dlm->node_num);
171         if (!master)
172                 res->state |= DLM_LOCK_RES_DROPPING_REF;
173         spin_unlock(&res->spinlock);
174
175         mlog(0, "purging lockres %.*s, master = %d\n", res->lockname.len,
176              res->lockname.name, master);
177
178         if (!master) {
179                 /* drop spinlock...  retake below */
180                 spin_unlock(&dlm->spinlock);
181
182                 spin_lock(&res->spinlock);
183                 /* This ensures that clear refmap is sent after the set */
184                 __dlm_wait_on_lockres_flags(res, DLM_LOCK_RES_SETREF_INPROG);
185                 spin_unlock(&res->spinlock);
186
187                 /* clear our bit from the master's refmap, ignore errors */
188                 ret = dlm_drop_lockres_ref(dlm, res);
189                 if (ret < 0) {
190                         mlog_errno(ret);
191                         if (!dlm_is_host_down(ret))
192                                 BUG();
193                 }
194                 mlog(0, "%s:%.*s: dlm_deref_lockres returned %d\n",
195                      dlm->name, res->lockname.len, res->lockname.name, ret);
196                 spin_lock(&dlm->spinlock);
197         }
198
199         if (!list_empty(&res->purge)) {
200                 mlog(0, "removing lockres %.*s:%p from purgelist, "
201                      "master = %d\n", res->lockname.len, res->lockname.name,
202                      res, master);
203                 list_del_init(&res->purge);
204                 dlm_lockres_put(res);
205                 dlm->purge_count--;
206         }
207         __dlm_unhash_lockres(res);
208
209         /* lockres is not in the hash now.  drop the flag and wake up
210          * any processes waiting in dlm_get_lock_resource. */
211         if (!master) {
212                 spin_lock(&res->spinlock);
213                 res->state &= ~DLM_LOCK_RES_DROPPING_REF;
214                 spin_unlock(&res->spinlock);
215                 wake_up(&res->wq);
216         }
217         return 0;
218 }
219
220 static void dlm_run_purge_list(struct dlm_ctxt *dlm,
221                                int purge_now)
222 {
223         unsigned int run_max, unused;
224         unsigned long purge_jiffies;
225         struct dlm_lock_resource *lockres;
226
227         spin_lock(&dlm->spinlock);
228         run_max = dlm->purge_count;
229
230         while(run_max && !list_empty(&dlm->purge_list)) {
231                 run_max--;
232
233                 lockres = list_entry(dlm->purge_list.next,
234                                      struct dlm_lock_resource, purge);
235
236                 /* Status of the lockres *might* change so double
237                  * check. If the lockres is unused, holding the dlm
238                  * spinlock will prevent people from getting and more
239                  * refs on it -- there's no need to keep the lockres
240                  * spinlock. */
241                 spin_lock(&lockres->spinlock);
242                 unused = __dlm_lockres_unused(lockres);
243                 spin_unlock(&lockres->spinlock);
244
245                 if (!unused)
246                         continue;
247
248                 purge_jiffies = lockres->last_used +
249                         msecs_to_jiffies(DLM_PURGE_INTERVAL_MS);
250
251                 /* Make sure that we want to be processing this guy at
252                  * this time. */
253                 if (!purge_now && time_after(purge_jiffies, jiffies)) {
254                         /* Since resources are added to the purge list
255                          * in tail order, we can stop at the first
256                          * unpurgable resource -- anyone added after
257                          * him will have a greater last_used value */
258                         break;
259                 }
260
261                 dlm_lockres_get(lockres);
262
263                 /* This may drop and reacquire the dlm spinlock if it
264                  * has to do migration. */
265                 if (dlm_purge_lockres(dlm, lockres))
266                         BUG();
267
268                 dlm_lockres_put(lockres);
269
270                 /* Avoid adding any scheduling latencies */
271                 cond_resched_lock(&dlm->spinlock);
272         }
273
274         spin_unlock(&dlm->spinlock);
275 }
276
277 static void dlm_shuffle_lists(struct dlm_ctxt *dlm,
278                               struct dlm_lock_resource *res)
279 {
280         struct dlm_lock *lock, *target;
281         struct list_head *iter;
282         struct list_head *head;
283         int can_grant = 1;
284
285         //mlog(0, "res->lockname.len=%d\n", res->lockname.len);
286         //mlog(0, "res->lockname.name=%p\n", res->lockname.name);
287         //mlog(0, "shuffle res %.*s\n", res->lockname.len,
288         //        res->lockname.name);
289
290         /* because this function is called with the lockres
291          * spinlock, and because we know that it is not migrating/
292          * recovering/in-progress, it is fine to reserve asts and
293          * basts right before queueing them all throughout */
294         assert_spin_locked(&res->spinlock);
295         BUG_ON((res->state & (DLM_LOCK_RES_MIGRATING|
296                               DLM_LOCK_RES_RECOVERING|
297                               DLM_LOCK_RES_IN_PROGRESS)));
298
299 converting:
300         if (list_empty(&res->converting))
301                 goto blocked;
302         mlog(0, "res %.*s has locks on a convert queue\n", res->lockname.len,
303              res->lockname.name);
304
305         target = list_entry(res->converting.next, struct dlm_lock, list);
306         if (target->ml.convert_type == LKM_IVMODE) {
307                 mlog(ML_ERROR, "%.*s: converting a lock with no "
308                      "convert_type!\n", res->lockname.len, res->lockname.name);
309                 BUG();
310         }
311         head = &res->granted;
312         list_for_each(iter, head) {
313                 lock = list_entry(iter, struct dlm_lock, list);
314                 if (lock==target)
315                         continue;
316                 if (!dlm_lock_compatible(lock->ml.type,
317                                          target->ml.convert_type)) {
318                         can_grant = 0;
319                         /* queue the BAST if not already */
320                         if (lock->ml.highest_blocked == LKM_IVMODE) {
321                                 __dlm_lockres_reserve_ast(res);
322                                 dlm_queue_bast(dlm, lock);
323                         }
324                         /* update the highest_blocked if needed */
325                         if (lock->ml.highest_blocked < target->ml.convert_type)
326                                 lock->ml.highest_blocked =
327                                         target->ml.convert_type;
328                 }
329         }
330         head = &res->converting;
331         list_for_each(iter, head) {
332                 lock = list_entry(iter, struct dlm_lock, list);
333                 if (lock==target)
334                         continue;
335                 if (!dlm_lock_compatible(lock->ml.type,
336                                          target->ml.convert_type)) {
337                         can_grant = 0;
338                         if (lock->ml.highest_blocked == LKM_IVMODE) {
339                                 __dlm_lockres_reserve_ast(res);
340                                 dlm_queue_bast(dlm, lock);
341                         }
342                         if (lock->ml.highest_blocked < target->ml.convert_type)
343                                 lock->ml.highest_blocked =
344                                         target->ml.convert_type;
345                 }
346         }
347
348         /* we can convert the lock */
349         if (can_grant) {
350                 spin_lock(&target->spinlock);
351                 BUG_ON(target->ml.highest_blocked != LKM_IVMODE);
352
353                 mlog(0, "calling ast for converting lock: %.*s, have: %d, "
354                      "granting: %d, node: %u\n", res->lockname.len,
355                      res->lockname.name, target->ml.type,
356                      target->ml.convert_type, target->ml.node);
357
358                 target->ml.type = target->ml.convert_type;
359                 target->ml.convert_type = LKM_IVMODE;
360                 list_move_tail(&target->list, &res->granted);
361
362                 BUG_ON(!target->lksb);
363                 target->lksb->status = DLM_NORMAL;
364
365                 spin_unlock(&target->spinlock);
366
367                 __dlm_lockres_reserve_ast(res);
368                 dlm_queue_ast(dlm, target);
369                 /* go back and check for more */
370                 goto converting;
371         }
372
373 blocked:
374         if (list_empty(&res->blocked))
375                 goto leave;
376         target = list_entry(res->blocked.next, struct dlm_lock, list);
377
378         head = &res->granted;
379         list_for_each(iter, head) {
380                 lock = list_entry(iter, struct dlm_lock, list);
381                 if (lock==target)
382                         continue;
383                 if (!dlm_lock_compatible(lock->ml.type, target->ml.type)) {
384                         can_grant = 0;
385                         if (lock->ml.highest_blocked == LKM_IVMODE) {
386                                 __dlm_lockres_reserve_ast(res);
387                                 dlm_queue_bast(dlm, lock);
388                         }
389                         if (lock->ml.highest_blocked < target->ml.type)
390                                 lock->ml.highest_blocked = target->ml.type;
391                 }
392         }
393
394         head = &res->converting;
395         list_for_each(iter, head) {
396                 lock = list_entry(iter, struct dlm_lock, list);
397                 if (lock==target)
398                         continue;
399                 if (!dlm_lock_compatible(lock->ml.type, target->ml.type)) {
400                         can_grant = 0;
401                         if (lock->ml.highest_blocked == LKM_IVMODE) {
402                                 __dlm_lockres_reserve_ast(res);
403                                 dlm_queue_bast(dlm, lock);
404                         }
405                         if (lock->ml.highest_blocked < target->ml.type)
406                                 lock->ml.highest_blocked = target->ml.type;
407                 }
408         }
409
410         /* we can grant the blocked lock (only
411          * possible if converting list empty) */
412         if (can_grant) {
413                 spin_lock(&target->spinlock);
414                 BUG_ON(target->ml.highest_blocked != LKM_IVMODE);
415
416                 mlog(0, "calling ast for blocked lock: %.*s, granting: %d, "
417                      "node: %u\n", res->lockname.len, res->lockname.name,
418                      target->ml.type, target->ml.node);
419
420                 // target->ml.type is already correct
421                 list_move_tail(&target->list, &res->granted);
422
423                 BUG_ON(!target->lksb);
424                 target->lksb->status = DLM_NORMAL;
425
426                 spin_unlock(&target->spinlock);
427
428                 __dlm_lockres_reserve_ast(res);
429                 dlm_queue_ast(dlm, target);
430                 /* go back and check for more */
431                 goto converting;
432         }
433
434 leave:
435         return;
436 }
437
438 /* must have NO locks when calling this with res !=NULL * */
439 void dlm_kick_thread(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
440 {
441         mlog_entry("dlm=%p, res=%p\n", dlm, res);
442         if (res) {
443                 spin_lock(&dlm->spinlock);
444                 spin_lock(&res->spinlock);
445                 __dlm_dirty_lockres(dlm, res);
446                 spin_unlock(&res->spinlock);
447                 spin_unlock(&dlm->spinlock);
448         }
449         wake_up(&dlm->dlm_thread_wq);
450 }
451
452 void __dlm_dirty_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
453 {
454         mlog_entry("dlm=%p, res=%p\n", dlm, res);
455
456         assert_spin_locked(&dlm->spinlock);
457         assert_spin_locked(&res->spinlock);
458
459         /* don't shuffle secondary queues */
460         if ((res->owner == dlm->node_num)) {
461                 if (res->state & (DLM_LOCK_RES_MIGRATING |
462                                   DLM_LOCK_RES_BLOCK_DIRTY))
463                     return;
464
465                 if (list_empty(&res->dirty)) {
466                         /* ref for dirty_list */
467                         dlm_lockres_get(res);
468                         list_add_tail(&res->dirty, &dlm->dirty_list);
469                         res->state |= DLM_LOCK_RES_DIRTY;
470                 }
471         }
472 }
473
474
475 /* Launch the NM thread for the mounted volume */
476 int dlm_launch_thread(struct dlm_ctxt *dlm)
477 {
478         mlog(0, "starting dlm thread...\n");
479
480         dlm->dlm_thread_task = kthread_run(dlm_thread, dlm, "dlm_thread");
481         if (IS_ERR(dlm->dlm_thread_task)) {
482                 mlog_errno(PTR_ERR(dlm->dlm_thread_task));
483                 dlm->dlm_thread_task = NULL;
484                 return -EINVAL;
485         }
486
487         return 0;
488 }
489
490 void dlm_complete_thread(struct dlm_ctxt *dlm)
491 {
492         if (dlm->dlm_thread_task) {
493                 mlog(ML_KTHREAD, "waiting for dlm thread to exit\n");
494                 kthread_stop(dlm->dlm_thread_task);
495                 dlm->dlm_thread_task = NULL;
496         }
497 }
498
499 static int dlm_dirty_list_empty(struct dlm_ctxt *dlm)
500 {
501         int empty;
502
503         spin_lock(&dlm->spinlock);
504         empty = list_empty(&dlm->dirty_list);
505         spin_unlock(&dlm->spinlock);
506
507         return empty;
508 }
509
510 static void dlm_flush_asts(struct dlm_ctxt *dlm)
511 {
512         int ret;
513         struct dlm_lock *lock;
514         struct dlm_lock_resource *res;
515         u8 hi;
516
517         spin_lock(&dlm->ast_lock);
518         while (!list_empty(&dlm->pending_asts)) {
519                 lock = list_entry(dlm->pending_asts.next,
520                                   struct dlm_lock, ast_list);
521                 /* get an extra ref on lock */
522                 dlm_lock_get(lock);
523                 res = lock->lockres;
524                 mlog(0, "delivering an ast for this lockres\n");
525
526                 BUG_ON(!lock->ast_pending);
527
528                 /* remove from list (including ref) */
529                 list_del_init(&lock->ast_list);
530                 dlm_lock_put(lock);
531                 spin_unlock(&dlm->ast_lock);
532
533                 if (lock->ml.node != dlm->node_num) {
534                         ret = dlm_do_remote_ast(dlm, res, lock);
535                         if (ret < 0)
536                                 mlog_errno(ret);
537                 } else
538                         dlm_do_local_ast(dlm, res, lock);
539
540                 spin_lock(&dlm->ast_lock);
541
542                 /* possible that another ast was queued while
543                  * we were delivering the last one */
544                 if (!list_empty(&lock->ast_list)) {
545                         mlog(0, "aha another ast got queued while "
546                              "we were finishing the last one.  will "
547                              "keep the ast_pending flag set.\n");
548                 } else
549                         lock->ast_pending = 0;
550
551                 /* drop the extra ref.
552                  * this may drop it completely. */
553                 dlm_lock_put(lock);
554                 dlm_lockres_release_ast(dlm, res);
555         }
556
557         while (!list_empty(&dlm->pending_basts)) {
558                 lock = list_entry(dlm->pending_basts.next,
559                                   struct dlm_lock, bast_list);
560                 /* get an extra ref on lock */
561                 dlm_lock_get(lock);
562                 res = lock->lockres;
563
564                 BUG_ON(!lock->bast_pending);
565
566                 /* get the highest blocked lock, and reset */
567                 spin_lock(&lock->spinlock);
568                 BUG_ON(lock->ml.highest_blocked <= LKM_IVMODE);
569                 hi = lock->ml.highest_blocked;
570                 lock->ml.highest_blocked = LKM_IVMODE;
571                 spin_unlock(&lock->spinlock);
572
573                 /* remove from list (including ref) */
574                 list_del_init(&lock->bast_list);
575                 dlm_lock_put(lock);
576                 spin_unlock(&dlm->ast_lock);
577
578                 mlog(0, "delivering a bast for this lockres "
579                      "(blocked = %d\n", hi);
580
581                 if (lock->ml.node != dlm->node_num) {
582                         ret = dlm_send_proxy_bast(dlm, res, lock, hi);
583                         if (ret < 0)
584                                 mlog_errno(ret);
585                 } else
586                         dlm_do_local_bast(dlm, res, lock, hi);
587
588                 spin_lock(&dlm->ast_lock);
589
590                 /* possible that another bast was queued while
591                  * we were delivering the last one */
592                 if (!list_empty(&lock->bast_list)) {
593                         mlog(0, "aha another bast got queued while "
594                              "we were finishing the last one.  will "
595                              "keep the bast_pending flag set.\n");
596                 } else
597                         lock->bast_pending = 0;
598
599                 /* drop the extra ref.
600                  * this may drop it completely. */
601                 dlm_lock_put(lock);
602                 dlm_lockres_release_ast(dlm, res);
603         }
604         wake_up(&dlm->ast_wq);
605         spin_unlock(&dlm->ast_lock);
606 }
607
608
609 #define DLM_THREAD_TIMEOUT_MS (4 * 1000)
610 #define DLM_THREAD_MAX_DIRTY  100
611 #define DLM_THREAD_MAX_ASTS   10
612
613 static int dlm_thread(void *data)
614 {
615         struct dlm_lock_resource *res;
616         struct dlm_ctxt *dlm = data;
617         unsigned long timeout = msecs_to_jiffies(DLM_THREAD_TIMEOUT_MS);
618
619         mlog(0, "dlm thread running for %s...\n", dlm->name);
620
621         while (!kthread_should_stop()) {
622                 int n = DLM_THREAD_MAX_DIRTY;
623
624                 /* dlm_shutting_down is very point-in-time, but that
625                  * doesn't matter as we'll just loop back around if we
626                  * get false on the leading edge of a state
627                  * transition. */
628                 dlm_run_purge_list(dlm, dlm_shutting_down(dlm));
629
630                 /* We really don't want to hold dlm->spinlock while
631                  * calling dlm_shuffle_lists on each lockres that
632                  * needs to have its queues adjusted and AST/BASTs
633                  * run.  So let's pull each entry off the dirty_list
634                  * and drop dlm->spinlock ASAP.  Once off the list,
635                  * res->spinlock needs to be taken again to protect
636                  * the queues while calling dlm_shuffle_lists.  */
637                 spin_lock(&dlm->spinlock);
638                 while (!list_empty(&dlm->dirty_list)) {
639                         int delay = 0;
640                         res = list_entry(dlm->dirty_list.next,
641                                          struct dlm_lock_resource, dirty);
642
643                         /* peel a lockres off, remove it from the list,
644                          * unset the dirty flag and drop the dlm lock */
645                         BUG_ON(!res);
646                         dlm_lockres_get(res);
647
648                         spin_lock(&res->spinlock);
649                         /* We clear the DLM_LOCK_RES_DIRTY state once we shuffle lists below */
650                         list_del_init(&res->dirty);
651                         spin_unlock(&res->spinlock);
652                         spin_unlock(&dlm->spinlock);
653                         /* Drop dirty_list ref */
654                         dlm_lockres_put(res);
655
656                         /* lockres can be re-dirtied/re-added to the
657                          * dirty_list in this gap, but that is ok */
658
659                         spin_lock(&res->spinlock);
660                         if (res->owner != dlm->node_num) {
661                                 __dlm_print_one_lock_resource(res);
662                                 mlog(ML_ERROR, "inprog:%s, mig:%s, reco:%s, dirty:%s\n",
663                                      res->state & DLM_LOCK_RES_IN_PROGRESS ? "yes" : "no",
664                                      res->state & DLM_LOCK_RES_MIGRATING ? "yes" : "no",
665                                      res->state & DLM_LOCK_RES_RECOVERING ? "yes" : "no",
666                                      res->state & DLM_LOCK_RES_DIRTY ? "yes" : "no");
667                         }
668                         BUG_ON(res->owner != dlm->node_num);
669
670                         /* it is now ok to move lockreses in these states
671                          * to the dirty list, assuming that they will only be
672                          * dirty for a short while. */
673                         BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
674                         if (res->state & (DLM_LOCK_RES_IN_PROGRESS |
675                                           DLM_LOCK_RES_RECOVERING)) {
676                                 /* move it to the tail and keep going */
677                                 res->state &= ~DLM_LOCK_RES_DIRTY;
678                                 spin_unlock(&res->spinlock);
679                                 mlog(0, "delaying list shuffling for in-"
680                                      "progress lockres %.*s, state=%d\n",
681                                      res->lockname.len, res->lockname.name,
682                                      res->state);
683                                 delay = 1;
684                                 goto in_progress;
685                         }
686
687                         /* at this point the lockres is not migrating/
688                          * recovering/in-progress.  we have the lockres
689                          * spinlock and do NOT have the dlm lock.
690                          * safe to reserve/queue asts and run the lists. */
691
692                         mlog(0, "calling dlm_shuffle_lists with dlm=%s, "
693                              "res=%.*s\n", dlm->name,
694                              res->lockname.len, res->lockname.name);
695
696                         /* called while holding lockres lock */
697                         dlm_shuffle_lists(dlm, res);
698                         res->state &= ~DLM_LOCK_RES_DIRTY;
699                         spin_unlock(&res->spinlock);
700
701                         dlm_lockres_calc_usage(dlm, res);
702
703 in_progress:
704
705                         spin_lock(&dlm->spinlock);
706                         /* if the lock was in-progress, stick
707                          * it on the back of the list */
708                         if (delay) {
709                                 spin_lock(&res->spinlock);
710                                 __dlm_dirty_lockres(dlm, res);
711                                 spin_unlock(&res->spinlock);
712                         }
713                         dlm_lockres_put(res);
714
715                         /* unlikely, but we may need to give time to
716                          * other tasks */
717                         if (!--n) {
718                                 mlog(0, "throttling dlm_thread\n");
719                                 break;
720                         }
721                 }
722
723                 spin_unlock(&dlm->spinlock);
724                 dlm_flush_asts(dlm);
725
726                 /* yield and continue right away if there is more work to do */
727                 if (!n) {
728                         cond_resched();
729                         continue;
730                 }
731
732                 wait_event_interruptible_timeout(dlm->dlm_thread_wq,
733                                                  !dlm_dirty_list_empty(dlm) ||
734                                                  kthread_should_stop(),
735                                                  timeout);
736         }
737
738         mlog(0, "quitting DLM thread\n");
739         return 0;
740 }