Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable
[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                                                   DLM_LOCK_RES_MIGRATING));
186                 spin_unlock(&res->spinlock);
187
188                 /* clear our bit from the master's refmap, ignore errors */
189                 ret = dlm_drop_lockres_ref(dlm, res);
190                 if (ret < 0) {
191                         mlog_errno(ret);
192                         if (!dlm_is_host_down(ret))
193                                 BUG();
194                 }
195                 mlog(0, "%s:%.*s: dlm_deref_lockres returned %d\n",
196                      dlm->name, res->lockname.len, res->lockname.name, ret);
197                 spin_lock(&dlm->spinlock);
198         }
199
200         if (!list_empty(&res->purge)) {
201                 mlog(0, "removing lockres %.*s:%p from purgelist, "
202                      "master = %d\n", res->lockname.len, res->lockname.name,
203                      res, master);
204                 list_del_init(&res->purge);
205                 dlm_lockres_put(res);
206                 dlm->purge_count--;
207         }
208         __dlm_unhash_lockres(res);
209
210         /* lockres is not in the hash now.  drop the flag and wake up
211          * any processes waiting in dlm_get_lock_resource. */
212         if (!master) {
213                 spin_lock(&res->spinlock);
214                 res->state &= ~DLM_LOCK_RES_DROPPING_REF;
215                 spin_unlock(&res->spinlock);
216                 wake_up(&res->wq);
217         }
218         return 0;
219 }
220
221 static void dlm_run_purge_list(struct dlm_ctxt *dlm,
222                                int purge_now)
223 {
224         unsigned int run_max, unused;
225         unsigned long purge_jiffies;
226         struct dlm_lock_resource *lockres;
227
228         spin_lock(&dlm->spinlock);
229         run_max = dlm->purge_count;
230
231         while(run_max && !list_empty(&dlm->purge_list)) {
232                 run_max--;
233
234                 lockres = list_entry(dlm->purge_list.next,
235                                      struct dlm_lock_resource, purge);
236
237                 /* Status of the lockres *might* change so double
238                  * check. If the lockres is unused, holding the dlm
239                  * spinlock will prevent people from getting and more
240                  * refs on it -- there's no need to keep the lockres
241                  * spinlock. */
242                 spin_lock(&lockres->spinlock);
243                 unused = __dlm_lockres_unused(lockres);
244                 spin_unlock(&lockres->spinlock);
245
246                 if (!unused)
247                         continue;
248
249                 purge_jiffies = lockres->last_used +
250                         msecs_to_jiffies(DLM_PURGE_INTERVAL_MS);
251
252                 /* Make sure that we want to be processing this guy at
253                  * this time. */
254                 if (!purge_now && time_after(purge_jiffies, jiffies)) {
255                         /* Since resources are added to the purge list
256                          * in tail order, we can stop at the first
257                          * unpurgable resource -- anyone added after
258                          * him will have a greater last_used value */
259                         break;
260                 }
261
262                 dlm_lockres_get(lockres);
263
264                 /* This may drop and reacquire the dlm spinlock if it
265                  * has to do migration. */
266                 if (dlm_purge_lockres(dlm, lockres))
267                         BUG();
268
269                 dlm_lockres_put(lockres);
270
271                 /* Avoid adding any scheduling latencies */
272                 cond_resched_lock(&dlm->spinlock);
273         }
274
275         spin_unlock(&dlm->spinlock);
276 }
277
278 static void dlm_shuffle_lists(struct dlm_ctxt *dlm,
279                               struct dlm_lock_resource *res)
280 {
281         struct dlm_lock *lock, *target;
282         struct list_head *iter;
283         struct list_head *head;
284         int can_grant = 1;
285
286         //mlog(0, "res->lockname.len=%d\n", res->lockname.len);
287         //mlog(0, "res->lockname.name=%p\n", res->lockname.name);
288         //mlog(0, "shuffle res %.*s\n", res->lockname.len,
289         //        res->lockname.name);
290
291         /* because this function is called with the lockres
292          * spinlock, and because we know that it is not migrating/
293          * recovering/in-progress, it is fine to reserve asts and
294          * basts right before queueing them all throughout */
295         assert_spin_locked(&res->spinlock);
296         BUG_ON((res->state & (DLM_LOCK_RES_MIGRATING|
297                               DLM_LOCK_RES_RECOVERING|
298                               DLM_LOCK_RES_IN_PROGRESS)));
299
300 converting:
301         if (list_empty(&res->converting))
302                 goto blocked;
303         mlog(0, "res %.*s has locks on a convert queue\n", res->lockname.len,
304              res->lockname.name);
305
306         target = list_entry(res->converting.next, struct dlm_lock, list);
307         if (target->ml.convert_type == LKM_IVMODE) {
308                 mlog(ML_ERROR, "%.*s: converting a lock with no "
309                      "convert_type!\n", res->lockname.len, res->lockname.name);
310                 BUG();
311         }
312         head = &res->granted;
313         list_for_each(iter, head) {
314                 lock = list_entry(iter, struct dlm_lock, list);
315                 if (lock==target)
316                         continue;
317                 if (!dlm_lock_compatible(lock->ml.type,
318                                          target->ml.convert_type)) {
319                         can_grant = 0;
320                         /* queue the BAST if not already */
321                         if (lock->ml.highest_blocked == LKM_IVMODE) {
322                                 __dlm_lockres_reserve_ast(res);
323                                 dlm_queue_bast(dlm, lock);
324                         }
325                         /* update the highest_blocked if needed */
326                         if (lock->ml.highest_blocked < target->ml.convert_type)
327                                 lock->ml.highest_blocked =
328                                         target->ml.convert_type;
329                 }
330         }
331         head = &res->converting;
332         list_for_each(iter, head) {
333                 lock = list_entry(iter, struct dlm_lock, list);
334                 if (lock==target)
335                         continue;
336                 if (!dlm_lock_compatible(lock->ml.type,
337                                          target->ml.convert_type)) {
338                         can_grant = 0;
339                         if (lock->ml.highest_blocked == LKM_IVMODE) {
340                                 __dlm_lockres_reserve_ast(res);
341                                 dlm_queue_bast(dlm, lock);
342                         }
343                         if (lock->ml.highest_blocked < target->ml.convert_type)
344                                 lock->ml.highest_blocked =
345                                         target->ml.convert_type;
346                 }
347         }
348
349         /* we can convert the lock */
350         if (can_grant) {
351                 spin_lock(&target->spinlock);
352                 BUG_ON(target->ml.highest_blocked != LKM_IVMODE);
353
354                 mlog(0, "calling ast for converting lock: %.*s, have: %d, "
355                      "granting: %d, node: %u\n", res->lockname.len,
356                      res->lockname.name, target->ml.type,
357                      target->ml.convert_type, target->ml.node);
358
359                 target->ml.type = target->ml.convert_type;
360                 target->ml.convert_type = LKM_IVMODE;
361                 list_move_tail(&target->list, &res->granted);
362
363                 BUG_ON(!target->lksb);
364                 target->lksb->status = DLM_NORMAL;
365
366                 spin_unlock(&target->spinlock);
367
368                 __dlm_lockres_reserve_ast(res);
369                 dlm_queue_ast(dlm, target);
370                 /* go back and check for more */
371                 goto converting;
372         }
373
374 blocked:
375         if (list_empty(&res->blocked))
376                 goto leave;
377         target = list_entry(res->blocked.next, struct dlm_lock, list);
378
379         head = &res->granted;
380         list_for_each(iter, head) {
381                 lock = list_entry(iter, struct dlm_lock, list);
382                 if (lock==target)
383                         continue;
384                 if (!dlm_lock_compatible(lock->ml.type, target->ml.type)) {
385                         can_grant = 0;
386                         if (lock->ml.highest_blocked == LKM_IVMODE) {
387                                 __dlm_lockres_reserve_ast(res);
388                                 dlm_queue_bast(dlm, lock);
389                         }
390                         if (lock->ml.highest_blocked < target->ml.type)
391                                 lock->ml.highest_blocked = target->ml.type;
392                 }
393         }
394
395         head = &res->converting;
396         list_for_each(iter, head) {
397                 lock = list_entry(iter, struct dlm_lock, list);
398                 if (lock==target)
399                         continue;
400                 if (!dlm_lock_compatible(lock->ml.type, target->ml.type)) {
401                         can_grant = 0;
402                         if (lock->ml.highest_blocked == LKM_IVMODE) {
403                                 __dlm_lockres_reserve_ast(res);
404                                 dlm_queue_bast(dlm, lock);
405                         }
406                         if (lock->ml.highest_blocked < target->ml.type)
407                                 lock->ml.highest_blocked = target->ml.type;
408                 }
409         }
410
411         /* we can grant the blocked lock (only
412          * possible if converting list empty) */
413         if (can_grant) {
414                 spin_lock(&target->spinlock);
415                 BUG_ON(target->ml.highest_blocked != LKM_IVMODE);
416
417                 mlog(0, "calling ast for blocked lock: %.*s, granting: %d, "
418                      "node: %u\n", res->lockname.len, res->lockname.name,
419                      target->ml.type, target->ml.node);
420
421                 // target->ml.type is already correct
422                 list_move_tail(&target->list, &res->granted);
423
424                 BUG_ON(!target->lksb);
425                 target->lksb->status = DLM_NORMAL;
426
427                 spin_unlock(&target->spinlock);
428
429                 __dlm_lockres_reserve_ast(res);
430                 dlm_queue_ast(dlm, target);
431                 /* go back and check for more */
432                 goto converting;
433         }
434
435 leave:
436         return;
437 }
438
439 /* must have NO locks when calling this with res !=NULL * */
440 void dlm_kick_thread(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
441 {
442         mlog_entry("dlm=%p, res=%p\n", dlm, res);
443         if (res) {
444                 spin_lock(&dlm->spinlock);
445                 spin_lock(&res->spinlock);
446                 __dlm_dirty_lockres(dlm, res);
447                 spin_unlock(&res->spinlock);
448                 spin_unlock(&dlm->spinlock);
449         }
450         wake_up(&dlm->dlm_thread_wq);
451 }
452
453 void __dlm_dirty_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
454 {
455         mlog_entry("dlm=%p, res=%p\n", dlm, res);
456
457         assert_spin_locked(&dlm->spinlock);
458         assert_spin_locked(&res->spinlock);
459
460         /* don't shuffle secondary queues */
461         if ((res->owner == dlm->node_num)) {
462                 if (res->state & (DLM_LOCK_RES_MIGRATING |
463                                   DLM_LOCK_RES_BLOCK_DIRTY))
464                     return;
465
466                 if (list_empty(&res->dirty)) {
467                         /* ref for dirty_list */
468                         dlm_lockres_get(res);
469                         list_add_tail(&res->dirty, &dlm->dirty_list);
470                         res->state |= DLM_LOCK_RES_DIRTY;
471                 }
472         }
473 }
474
475
476 /* Launch the NM thread for the mounted volume */
477 int dlm_launch_thread(struct dlm_ctxt *dlm)
478 {
479         mlog(0, "starting dlm thread...\n");
480
481         dlm->dlm_thread_task = kthread_run(dlm_thread, dlm, "dlm_thread");
482         if (IS_ERR(dlm->dlm_thread_task)) {
483                 mlog_errno(PTR_ERR(dlm->dlm_thread_task));
484                 dlm->dlm_thread_task = NULL;
485                 return -EINVAL;
486         }
487
488         return 0;
489 }
490
491 void dlm_complete_thread(struct dlm_ctxt *dlm)
492 {
493         if (dlm->dlm_thread_task) {
494                 mlog(ML_KTHREAD, "waiting for dlm thread to exit\n");
495                 kthread_stop(dlm->dlm_thread_task);
496                 dlm->dlm_thread_task = NULL;
497         }
498 }
499
500 static int dlm_dirty_list_empty(struct dlm_ctxt *dlm)
501 {
502         int empty;
503
504         spin_lock(&dlm->spinlock);
505         empty = list_empty(&dlm->dirty_list);
506         spin_unlock(&dlm->spinlock);
507
508         return empty;
509 }
510
511 static void dlm_flush_asts(struct dlm_ctxt *dlm)
512 {
513         int ret;
514         struct dlm_lock *lock;
515         struct dlm_lock_resource *res;
516         u8 hi;
517
518         spin_lock(&dlm->ast_lock);
519         while (!list_empty(&dlm->pending_asts)) {
520                 lock = list_entry(dlm->pending_asts.next,
521                                   struct dlm_lock, ast_list);
522                 /* get an extra ref on lock */
523                 dlm_lock_get(lock);
524                 res = lock->lockres;
525                 mlog(0, "delivering an ast for this lockres\n");
526
527                 BUG_ON(!lock->ast_pending);
528
529                 /* remove from list (including ref) */
530                 list_del_init(&lock->ast_list);
531                 dlm_lock_put(lock);
532                 spin_unlock(&dlm->ast_lock);
533
534                 if (lock->ml.node != dlm->node_num) {
535                         ret = dlm_do_remote_ast(dlm, res, lock);
536                         if (ret < 0)
537                                 mlog_errno(ret);
538                 } else
539                         dlm_do_local_ast(dlm, res, lock);
540
541                 spin_lock(&dlm->ast_lock);
542
543                 /* possible that another ast was queued while
544                  * we were delivering the last one */
545                 if (!list_empty(&lock->ast_list)) {
546                         mlog(0, "aha another ast got queued while "
547                              "we were finishing the last one.  will "
548                              "keep the ast_pending flag set.\n");
549                 } else
550                         lock->ast_pending = 0;
551
552                 /* drop the extra ref.
553                  * this may drop it completely. */
554                 dlm_lock_put(lock);
555                 dlm_lockres_release_ast(dlm, res);
556         }
557
558         while (!list_empty(&dlm->pending_basts)) {
559                 lock = list_entry(dlm->pending_basts.next,
560                                   struct dlm_lock, bast_list);
561                 /* get an extra ref on lock */
562                 dlm_lock_get(lock);
563                 res = lock->lockres;
564
565                 BUG_ON(!lock->bast_pending);
566
567                 /* get the highest blocked lock, and reset */
568                 spin_lock(&lock->spinlock);
569                 BUG_ON(lock->ml.highest_blocked <= LKM_IVMODE);
570                 hi = lock->ml.highest_blocked;
571                 lock->ml.highest_blocked = LKM_IVMODE;
572                 spin_unlock(&lock->spinlock);
573
574                 /* remove from list (including ref) */
575                 list_del_init(&lock->bast_list);
576                 dlm_lock_put(lock);
577                 spin_unlock(&dlm->ast_lock);
578
579                 mlog(0, "delivering a bast for this lockres "
580                      "(blocked = %d\n", hi);
581
582                 if (lock->ml.node != dlm->node_num) {
583                         ret = dlm_send_proxy_bast(dlm, res, lock, hi);
584                         if (ret < 0)
585                                 mlog_errno(ret);
586                 } else
587                         dlm_do_local_bast(dlm, res, lock, hi);
588
589                 spin_lock(&dlm->ast_lock);
590
591                 /* possible that another bast was queued while
592                  * we were delivering the last one */
593                 if (!list_empty(&lock->bast_list)) {
594                         mlog(0, "aha another bast got queued while "
595                              "we were finishing the last one.  will "
596                              "keep the bast_pending flag set.\n");
597                 } else
598                         lock->bast_pending = 0;
599
600                 /* drop the extra ref.
601                  * this may drop it completely. */
602                 dlm_lock_put(lock);
603                 dlm_lockres_release_ast(dlm, res);
604         }
605         wake_up(&dlm->ast_wq);
606         spin_unlock(&dlm->ast_lock);
607 }
608
609
610 #define DLM_THREAD_TIMEOUT_MS (4 * 1000)
611 #define DLM_THREAD_MAX_DIRTY  100
612 #define DLM_THREAD_MAX_ASTS   10
613
614 static int dlm_thread(void *data)
615 {
616         struct dlm_lock_resource *res;
617         struct dlm_ctxt *dlm = data;
618         unsigned long timeout = msecs_to_jiffies(DLM_THREAD_TIMEOUT_MS);
619
620         mlog(0, "dlm thread running for %s...\n", dlm->name);
621
622         while (!kthread_should_stop()) {
623                 int n = DLM_THREAD_MAX_DIRTY;
624
625                 /* dlm_shutting_down is very point-in-time, but that
626                  * doesn't matter as we'll just loop back around if we
627                  * get false on the leading edge of a state
628                  * transition. */
629                 dlm_run_purge_list(dlm, dlm_shutting_down(dlm));
630
631                 /* We really don't want to hold dlm->spinlock while
632                  * calling dlm_shuffle_lists on each lockres that
633                  * needs to have its queues adjusted and AST/BASTs
634                  * run.  So let's pull each entry off the dirty_list
635                  * and drop dlm->spinlock ASAP.  Once off the list,
636                  * res->spinlock needs to be taken again to protect
637                  * the queues while calling dlm_shuffle_lists.  */
638                 spin_lock(&dlm->spinlock);
639                 while (!list_empty(&dlm->dirty_list)) {
640                         int delay = 0;
641                         res = list_entry(dlm->dirty_list.next,
642                                          struct dlm_lock_resource, dirty);
643
644                         /* peel a lockres off, remove it from the list,
645                          * unset the dirty flag and drop the dlm lock */
646                         BUG_ON(!res);
647                         dlm_lockres_get(res);
648
649                         spin_lock(&res->spinlock);
650                         /* We clear the DLM_LOCK_RES_DIRTY state once we shuffle lists below */
651                         list_del_init(&res->dirty);
652                         spin_unlock(&res->spinlock);
653                         spin_unlock(&dlm->spinlock);
654                         /* Drop dirty_list ref */
655                         dlm_lockres_put(res);
656
657                         /* lockres can be re-dirtied/re-added to the
658                          * dirty_list in this gap, but that is ok */
659
660                         spin_lock(&res->spinlock);
661                         if (res->owner != dlm->node_num) {
662                                 __dlm_print_one_lock_resource(res);
663                                 mlog(ML_ERROR, "inprog:%s, mig:%s, reco:%s, dirty:%s\n",
664                                      res->state & DLM_LOCK_RES_IN_PROGRESS ? "yes" : "no",
665                                      res->state & DLM_LOCK_RES_MIGRATING ? "yes" : "no",
666                                      res->state & DLM_LOCK_RES_RECOVERING ? "yes" : "no",
667                                      res->state & DLM_LOCK_RES_DIRTY ? "yes" : "no");
668                         }
669                         BUG_ON(res->owner != dlm->node_num);
670
671                         /* it is now ok to move lockreses in these states
672                          * to the dirty list, assuming that they will only be
673                          * dirty for a short while. */
674                         BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
675                         if (res->state & (DLM_LOCK_RES_IN_PROGRESS |
676                                           DLM_LOCK_RES_RECOVERING)) {
677                                 /* move it to the tail and keep going */
678                                 res->state &= ~DLM_LOCK_RES_DIRTY;
679                                 spin_unlock(&res->spinlock);
680                                 mlog(0, "delaying list shuffling for in-"
681                                      "progress lockres %.*s, state=%d\n",
682                                      res->lockname.len, res->lockname.name,
683                                      res->state);
684                                 delay = 1;
685                                 goto in_progress;
686                         }
687
688                         /* at this point the lockres is not migrating/
689                          * recovering/in-progress.  we have the lockres
690                          * spinlock and do NOT have the dlm lock.
691                          * safe to reserve/queue asts and run the lists. */
692
693                         mlog(0, "calling dlm_shuffle_lists with dlm=%s, "
694                              "res=%.*s\n", dlm->name,
695                              res->lockname.len, res->lockname.name);
696
697                         /* called while holding lockres lock */
698                         dlm_shuffle_lists(dlm, res);
699                         res->state &= ~DLM_LOCK_RES_DIRTY;
700                         spin_unlock(&res->spinlock);
701
702                         dlm_lockres_calc_usage(dlm, res);
703
704 in_progress:
705
706                         spin_lock(&dlm->spinlock);
707                         /* if the lock was in-progress, stick
708                          * it on the back of the list */
709                         if (delay) {
710                                 spin_lock(&res->spinlock);
711                                 __dlm_dirty_lockres(dlm, res);
712                                 spin_unlock(&res->spinlock);
713                         }
714                         dlm_lockres_put(res);
715
716                         /* unlikely, but we may need to give time to
717                          * other tasks */
718                         if (!--n) {
719                                 mlog(0, "throttling dlm_thread\n");
720                                 break;
721                         }
722                 }
723
724                 spin_unlock(&dlm->spinlock);
725                 dlm_flush_asts(dlm);
726
727                 /* yield and continue right away if there is more work to do */
728                 if (!n) {
729                         cond_resched();
730                         continue;
731                 }
732
733                 wait_event_interruptible_timeout(dlm->dlm_thread_wq,
734                                                  !dlm_dirty_list_empty(dlm) ||
735                                                  kthread_should_stop(),
736                                                  timeout);
737         }
738
739         mlog(0, "quitting DLM thread\n");
740         return 0;
741 }