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