ext4: Optimize ext4 DIO overwrites
[linux/fpc-iii.git] / fs / ocfs2 / dlm / dlmthread.c
blob61c51c268460a28f50a60088b09ac9382126ac86
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* -*- mode: c; c-basic-offset: 8; -*-
3 * vim: noexpandtab sw=8 ts=8 sts=0:
5 * dlmthread.c
7 * standalone DLM module
9 * Copyright (C) 2004 Oracle. All rights reserved.
13 #include <linux/module.h>
14 #include <linux/fs.h>
15 #include <linux/types.h>
16 #include <linux/highmem.h>
17 #include <linux/init.h>
18 #include <linux/sysctl.h>
19 #include <linux/random.h>
20 #include <linux/blkdev.h>
21 #include <linux/socket.h>
22 #include <linux/inet.h>
23 #include <linux/timer.h>
24 #include <linux/kthread.h>
25 #include <linux/delay.h>
28 #include "cluster/heartbeat.h"
29 #include "cluster/nodemanager.h"
30 #include "cluster/tcp.h"
32 #include "dlmapi.h"
33 #include "dlmcommon.h"
34 #include "dlmdomain.h"
36 #define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_THREAD)
37 #include "cluster/masklog.h"
39 static int dlm_thread(void *data);
40 static void dlm_flush_asts(struct dlm_ctxt *dlm);
42 #define dlm_lock_is_remote(dlm, lock) ((lock)->ml.node != (dlm)->node_num)
44 /* will exit holding res->spinlock, but may drop in function */
45 /* waits until flags are cleared on res->state */
46 void __dlm_wait_on_lockres_flags(struct dlm_lock_resource *res, int flags)
48 DECLARE_WAITQUEUE(wait, current);
50 assert_spin_locked(&res->spinlock);
52 add_wait_queue(&res->wq, &wait);
53 repeat:
54 set_current_state(TASK_UNINTERRUPTIBLE);
55 if (res->state & flags) {
56 spin_unlock(&res->spinlock);
57 schedule();
58 spin_lock(&res->spinlock);
59 goto repeat;
61 remove_wait_queue(&res->wq, &wait);
62 __set_current_state(TASK_RUNNING);
65 int __dlm_lockres_has_locks(struct dlm_lock_resource *res)
67 if (list_empty(&res->granted) &&
68 list_empty(&res->converting) &&
69 list_empty(&res->blocked))
70 return 0;
71 return 1;
74 /* "unused": the lockres has no locks, is not on the dirty list,
75 * has no inflight locks (in the gap between mastery and acquiring
76 * the first lock), and has no bits in its refmap.
77 * truly ready to be freed. */
78 int __dlm_lockres_unused(struct dlm_lock_resource *res)
80 int bit;
82 assert_spin_locked(&res->spinlock);
84 if (__dlm_lockres_has_locks(res))
85 return 0;
87 /* Locks are in the process of being created */
88 if (res->inflight_locks)
89 return 0;
91 if (!list_empty(&res->dirty) || res->state & DLM_LOCK_RES_DIRTY)
92 return 0;
94 if (res->state & (DLM_LOCK_RES_RECOVERING|
95 DLM_LOCK_RES_RECOVERY_WAITING))
96 return 0;
98 /* Another node has this resource with this node as the master */
99 bit = find_next_bit(res->refmap, O2NM_MAX_NODES, 0);
100 if (bit < O2NM_MAX_NODES)
101 return 0;
103 return 1;
107 /* Call whenever you may have added or deleted something from one of
108 * the lockres queue's. This will figure out whether it belongs on the
109 * unused list or not and does the appropriate thing. */
110 void __dlm_lockres_calc_usage(struct dlm_ctxt *dlm,
111 struct dlm_lock_resource *res)
113 assert_spin_locked(&dlm->spinlock);
114 assert_spin_locked(&res->spinlock);
116 if (__dlm_lockres_unused(res)){
117 if (list_empty(&res->purge)) {
118 mlog(0, "%s: Adding res %.*s to purge list\n",
119 dlm->name, res->lockname.len, res->lockname.name);
121 res->last_used = jiffies;
122 dlm_lockres_get(res);
123 list_add_tail(&res->purge, &dlm->purge_list);
124 dlm->purge_count++;
126 } else if (!list_empty(&res->purge)) {
127 mlog(0, "%s: Removing res %.*s from purge list\n",
128 dlm->name, res->lockname.len, res->lockname.name);
130 list_del_init(&res->purge);
131 dlm_lockres_put(res);
132 dlm->purge_count--;
136 void dlm_lockres_calc_usage(struct dlm_ctxt *dlm,
137 struct dlm_lock_resource *res)
139 spin_lock(&dlm->spinlock);
140 spin_lock(&res->spinlock);
142 __dlm_lockres_calc_usage(dlm, res);
144 spin_unlock(&res->spinlock);
145 spin_unlock(&dlm->spinlock);
149 * Do the real purge work:
150 * unhash the lockres, and
151 * clear flag DLM_LOCK_RES_DROPPING_REF.
152 * It requires dlm and lockres spinlock to be taken.
154 void __dlm_do_purge_lockres(struct dlm_ctxt *dlm,
155 struct dlm_lock_resource *res)
157 assert_spin_locked(&dlm->spinlock);
158 assert_spin_locked(&res->spinlock);
160 if (!list_empty(&res->purge)) {
161 mlog(0, "%s: Removing res %.*s from purgelist\n",
162 dlm->name, res->lockname.len, res->lockname.name);
163 list_del_init(&res->purge);
164 dlm_lockres_put(res);
165 dlm->purge_count--;
168 if (!__dlm_lockres_unused(res)) {
169 mlog(ML_ERROR, "%s: res %.*s in use after deref\n",
170 dlm->name, res->lockname.len, res->lockname.name);
171 __dlm_print_one_lock_resource(res);
172 BUG();
175 __dlm_unhash_lockres(dlm, res);
177 spin_lock(&dlm->track_lock);
178 if (!list_empty(&res->tracking))
179 list_del_init(&res->tracking);
180 else {
181 mlog(ML_ERROR, "%s: Resource %.*s not on the Tracking list\n",
182 dlm->name, res->lockname.len, res->lockname.name);
183 __dlm_print_one_lock_resource(res);
185 spin_unlock(&dlm->track_lock);
188 * lockres is not in the hash now. drop the flag and wake up
189 * any processes waiting in dlm_get_lock_resource.
191 res->state &= ~DLM_LOCK_RES_DROPPING_REF;
194 static void dlm_purge_lockres(struct dlm_ctxt *dlm,
195 struct dlm_lock_resource *res)
197 int master;
198 int ret = 0;
200 assert_spin_locked(&dlm->spinlock);
201 assert_spin_locked(&res->spinlock);
203 master = (res->owner == dlm->node_num);
205 mlog(0, "%s: Purging res %.*s, master %d\n", dlm->name,
206 res->lockname.len, res->lockname.name, master);
208 if (!master) {
209 if (res->state & DLM_LOCK_RES_DROPPING_REF) {
210 mlog(ML_NOTICE, "%s: res %.*s already in DLM_LOCK_RES_DROPPING_REF state\n",
211 dlm->name, res->lockname.len, res->lockname.name);
212 spin_unlock(&res->spinlock);
213 return;
216 res->state |= DLM_LOCK_RES_DROPPING_REF;
217 /* drop spinlock... retake below */
218 spin_unlock(&res->spinlock);
219 spin_unlock(&dlm->spinlock);
221 spin_lock(&res->spinlock);
222 /* This ensures that clear refmap is sent after the set */
223 __dlm_wait_on_lockres_flags(res, DLM_LOCK_RES_SETREF_INPROG);
224 spin_unlock(&res->spinlock);
226 /* clear our bit from the master's refmap, ignore errors */
227 ret = dlm_drop_lockres_ref(dlm, res);
228 if (ret < 0) {
229 if (!dlm_is_host_down(ret))
230 BUG();
232 spin_lock(&dlm->spinlock);
233 spin_lock(&res->spinlock);
236 if (!list_empty(&res->purge)) {
237 mlog(0, "%s: Removing res %.*s from purgelist, master %d\n",
238 dlm->name, res->lockname.len, res->lockname.name, master);
239 list_del_init(&res->purge);
240 dlm_lockres_put(res);
241 dlm->purge_count--;
244 if (!master && ret == DLM_DEREF_RESPONSE_INPROG) {
245 mlog(0, "%s: deref %.*s in progress\n",
246 dlm->name, res->lockname.len, res->lockname.name);
247 spin_unlock(&res->spinlock);
248 return;
251 if (!__dlm_lockres_unused(res)) {
252 mlog(ML_ERROR, "%s: res %.*s in use after deref\n",
253 dlm->name, res->lockname.len, res->lockname.name);
254 __dlm_print_one_lock_resource(res);
255 BUG();
258 __dlm_unhash_lockres(dlm, res);
260 spin_lock(&dlm->track_lock);
261 if (!list_empty(&res->tracking))
262 list_del_init(&res->tracking);
263 else {
264 mlog(ML_ERROR, "Resource %.*s not on the Tracking list\n",
265 res->lockname.len, res->lockname.name);
266 __dlm_print_one_lock_resource(res);
268 spin_unlock(&dlm->track_lock);
270 /* lockres is not in the hash now. drop the flag and wake up
271 * any processes waiting in dlm_get_lock_resource. */
272 if (!master) {
273 res->state &= ~DLM_LOCK_RES_DROPPING_REF;
274 spin_unlock(&res->spinlock);
275 wake_up(&res->wq);
276 } else
277 spin_unlock(&res->spinlock);
280 static void dlm_run_purge_list(struct dlm_ctxt *dlm,
281 int purge_now)
283 unsigned int run_max, unused;
284 unsigned long purge_jiffies;
285 struct dlm_lock_resource *lockres;
287 spin_lock(&dlm->spinlock);
288 run_max = dlm->purge_count;
290 while(run_max && !list_empty(&dlm->purge_list)) {
291 run_max--;
293 lockres = list_entry(dlm->purge_list.next,
294 struct dlm_lock_resource, purge);
296 spin_lock(&lockres->spinlock);
298 purge_jiffies = lockres->last_used +
299 msecs_to_jiffies(DLM_PURGE_INTERVAL_MS);
301 /* Make sure that we want to be processing this guy at
302 * this time. */
303 if (!purge_now && time_after(purge_jiffies, jiffies)) {
304 /* Since resources are added to the purge list
305 * in tail order, we can stop at the first
306 * unpurgable resource -- anyone added after
307 * him will have a greater last_used value */
308 spin_unlock(&lockres->spinlock);
309 break;
312 /* Status of the lockres *might* change so double
313 * check. If the lockres is unused, holding the dlm
314 * spinlock will prevent people from getting and more
315 * refs on it. */
316 unused = __dlm_lockres_unused(lockres);
317 if (!unused ||
318 (lockres->state & DLM_LOCK_RES_MIGRATING) ||
319 (lockres->inflight_assert_workers != 0)) {
320 mlog(0, "%s: res %.*s is in use or being remastered, "
321 "used %d, state %d, assert master workers %u\n",
322 dlm->name, lockres->lockname.len,
323 lockres->lockname.name,
324 !unused, lockres->state,
325 lockres->inflight_assert_workers);
326 list_move_tail(&lockres->purge, &dlm->purge_list);
327 spin_unlock(&lockres->spinlock);
328 continue;
331 dlm_lockres_get(lockres);
333 dlm_purge_lockres(dlm, lockres);
335 dlm_lockres_put(lockres);
337 /* Avoid adding any scheduling latencies */
338 cond_resched_lock(&dlm->spinlock);
341 spin_unlock(&dlm->spinlock);
344 static void dlm_shuffle_lists(struct dlm_ctxt *dlm,
345 struct dlm_lock_resource *res)
347 struct dlm_lock *lock, *target;
348 int can_grant = 1;
351 * Because this function is called with the lockres
352 * spinlock, and because we know that it is not migrating/
353 * recovering/in-progress, it is fine to reserve asts and
354 * basts right before queueing them all throughout
356 assert_spin_locked(&dlm->ast_lock);
357 assert_spin_locked(&res->spinlock);
358 BUG_ON((res->state & (DLM_LOCK_RES_MIGRATING|
359 DLM_LOCK_RES_RECOVERING|
360 DLM_LOCK_RES_IN_PROGRESS)));
362 converting:
363 if (list_empty(&res->converting))
364 goto blocked;
365 mlog(0, "%s: res %.*s has locks on the convert queue\n", dlm->name,
366 res->lockname.len, res->lockname.name);
368 target = list_entry(res->converting.next, struct dlm_lock, list);
369 if (target->ml.convert_type == LKM_IVMODE) {
370 mlog(ML_ERROR, "%s: res %.*s converting lock to invalid mode\n",
371 dlm->name, res->lockname.len, res->lockname.name);
372 BUG();
374 list_for_each_entry(lock, &res->granted, list) {
375 if (lock==target)
376 continue;
377 if (!dlm_lock_compatible(lock->ml.type,
378 target->ml.convert_type)) {
379 can_grant = 0;
380 /* queue the BAST if not already */
381 if (lock->ml.highest_blocked == LKM_IVMODE) {
382 __dlm_lockres_reserve_ast(res);
383 __dlm_queue_bast(dlm, lock);
385 /* update the highest_blocked if needed */
386 if (lock->ml.highest_blocked < target->ml.convert_type)
387 lock->ml.highest_blocked =
388 target->ml.convert_type;
392 list_for_each_entry(lock, &res->converting, list) {
393 if (lock==target)
394 continue;
395 if (!dlm_lock_compatible(lock->ml.type,
396 target->ml.convert_type)) {
397 can_grant = 0;
398 if (lock->ml.highest_blocked == LKM_IVMODE) {
399 __dlm_lockres_reserve_ast(res);
400 __dlm_queue_bast(dlm, lock);
402 if (lock->ml.highest_blocked < target->ml.convert_type)
403 lock->ml.highest_blocked =
404 target->ml.convert_type;
408 /* we can convert the lock */
409 if (can_grant) {
410 spin_lock(&target->spinlock);
411 BUG_ON(target->ml.highest_blocked != LKM_IVMODE);
413 mlog(0, "%s: res %.*s, AST for Converting lock %u:%llu, type "
414 "%d => %d, node %u\n", dlm->name, res->lockname.len,
415 res->lockname.name,
416 dlm_get_lock_cookie_node(be64_to_cpu(target->ml.cookie)),
417 dlm_get_lock_cookie_seq(be64_to_cpu(target->ml.cookie)),
418 target->ml.type,
419 target->ml.convert_type, target->ml.node);
421 target->ml.type = target->ml.convert_type;
422 target->ml.convert_type = LKM_IVMODE;
423 list_move_tail(&target->list, &res->granted);
425 BUG_ON(!target->lksb);
426 target->lksb->status = DLM_NORMAL;
428 spin_unlock(&target->spinlock);
430 __dlm_lockres_reserve_ast(res);
431 __dlm_queue_ast(dlm, target);
432 /* go back and check for more */
433 goto converting;
436 blocked:
437 if (list_empty(&res->blocked))
438 goto leave;
439 target = list_entry(res->blocked.next, struct dlm_lock, list);
441 list_for_each_entry(lock, &res->granted, list) {
442 if (lock==target)
443 continue;
444 if (!dlm_lock_compatible(lock->ml.type, target->ml.type)) {
445 can_grant = 0;
446 if (lock->ml.highest_blocked == LKM_IVMODE) {
447 __dlm_lockres_reserve_ast(res);
448 __dlm_queue_bast(dlm, lock);
450 if (lock->ml.highest_blocked < target->ml.type)
451 lock->ml.highest_blocked = target->ml.type;
455 list_for_each_entry(lock, &res->converting, list) {
456 if (lock==target)
457 continue;
458 if (!dlm_lock_compatible(lock->ml.type, target->ml.type)) {
459 can_grant = 0;
460 if (lock->ml.highest_blocked == LKM_IVMODE) {
461 __dlm_lockres_reserve_ast(res);
462 __dlm_queue_bast(dlm, lock);
464 if (lock->ml.highest_blocked < target->ml.type)
465 lock->ml.highest_blocked = target->ml.type;
469 /* we can grant the blocked lock (only
470 * possible if converting list empty) */
471 if (can_grant) {
472 spin_lock(&target->spinlock);
473 BUG_ON(target->ml.highest_blocked != LKM_IVMODE);
475 mlog(0, "%s: res %.*s, AST for Blocked lock %u:%llu, type %d, "
476 "node %u\n", dlm->name, res->lockname.len,
477 res->lockname.name,
478 dlm_get_lock_cookie_node(be64_to_cpu(target->ml.cookie)),
479 dlm_get_lock_cookie_seq(be64_to_cpu(target->ml.cookie)),
480 target->ml.type, target->ml.node);
482 /* target->ml.type is already correct */
483 list_move_tail(&target->list, &res->granted);
485 BUG_ON(!target->lksb);
486 target->lksb->status = DLM_NORMAL;
488 spin_unlock(&target->spinlock);
490 __dlm_lockres_reserve_ast(res);
491 __dlm_queue_ast(dlm, target);
492 /* go back and check for more */
493 goto converting;
496 leave:
497 return;
500 /* must have NO locks when calling this with res !=NULL * */
501 void dlm_kick_thread(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
503 if (res) {
504 spin_lock(&dlm->spinlock);
505 spin_lock(&res->spinlock);
506 __dlm_dirty_lockres(dlm, res);
507 spin_unlock(&res->spinlock);
508 spin_unlock(&dlm->spinlock);
510 wake_up(&dlm->dlm_thread_wq);
513 void __dlm_dirty_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
515 assert_spin_locked(&dlm->spinlock);
516 assert_spin_locked(&res->spinlock);
518 /* don't shuffle secondary queues */
519 if (res->owner == dlm->node_num) {
520 if (res->state & (DLM_LOCK_RES_MIGRATING |
521 DLM_LOCK_RES_BLOCK_DIRTY))
522 return;
524 if (list_empty(&res->dirty)) {
525 /* ref for dirty_list */
526 dlm_lockres_get(res);
527 list_add_tail(&res->dirty, &dlm->dirty_list);
528 res->state |= DLM_LOCK_RES_DIRTY;
532 mlog(0, "%s: res %.*s\n", dlm->name, res->lockname.len,
533 res->lockname.name);
537 /* Launch the NM thread for the mounted volume */
538 int dlm_launch_thread(struct dlm_ctxt *dlm)
540 mlog(0, "Starting dlm_thread...\n");
542 dlm->dlm_thread_task = kthread_run(dlm_thread, dlm, "dlm-%s",
543 dlm->name);
544 if (IS_ERR(dlm->dlm_thread_task)) {
545 mlog_errno(PTR_ERR(dlm->dlm_thread_task));
546 dlm->dlm_thread_task = NULL;
547 return -EINVAL;
550 return 0;
553 void dlm_complete_thread(struct dlm_ctxt *dlm)
555 if (dlm->dlm_thread_task) {
556 mlog(ML_KTHREAD, "Waiting for dlm thread to exit\n");
557 kthread_stop(dlm->dlm_thread_task);
558 dlm->dlm_thread_task = NULL;
562 static int dlm_dirty_list_empty(struct dlm_ctxt *dlm)
564 int empty;
566 spin_lock(&dlm->spinlock);
567 empty = list_empty(&dlm->dirty_list);
568 spin_unlock(&dlm->spinlock);
570 return empty;
573 static void dlm_flush_asts(struct dlm_ctxt *dlm)
575 int ret;
576 struct dlm_lock *lock;
577 struct dlm_lock_resource *res;
578 u8 hi;
580 spin_lock(&dlm->ast_lock);
581 while (!list_empty(&dlm->pending_asts)) {
582 lock = list_entry(dlm->pending_asts.next,
583 struct dlm_lock, ast_list);
584 /* get an extra ref on lock */
585 dlm_lock_get(lock);
586 res = lock->lockres;
587 mlog(0, "%s: res %.*s, Flush AST for lock %u:%llu, type %d, "
588 "node %u\n", dlm->name, res->lockname.len,
589 res->lockname.name,
590 dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
591 dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
592 lock->ml.type, lock->ml.node);
594 BUG_ON(!lock->ast_pending);
596 /* remove from list (including ref) */
597 list_del_init(&lock->ast_list);
598 dlm_lock_put(lock);
599 spin_unlock(&dlm->ast_lock);
601 if (lock->ml.node != dlm->node_num) {
602 ret = dlm_do_remote_ast(dlm, res, lock);
603 if (ret < 0)
604 mlog_errno(ret);
605 } else
606 dlm_do_local_ast(dlm, res, lock);
608 spin_lock(&dlm->ast_lock);
610 /* possible that another ast was queued while
611 * we were delivering the last one */
612 if (!list_empty(&lock->ast_list)) {
613 mlog(0, "%s: res %.*s, AST queued while flushing last "
614 "one\n", dlm->name, res->lockname.len,
615 res->lockname.name);
616 } else
617 lock->ast_pending = 0;
619 /* drop the extra ref.
620 * this may drop it completely. */
621 dlm_lock_put(lock);
622 dlm_lockres_release_ast(dlm, res);
625 while (!list_empty(&dlm->pending_basts)) {
626 lock = list_entry(dlm->pending_basts.next,
627 struct dlm_lock, bast_list);
628 /* get an extra ref on lock */
629 dlm_lock_get(lock);
630 res = lock->lockres;
632 BUG_ON(!lock->bast_pending);
634 /* get the highest blocked lock, and reset */
635 spin_lock(&lock->spinlock);
636 BUG_ON(lock->ml.highest_blocked <= LKM_IVMODE);
637 hi = lock->ml.highest_blocked;
638 lock->ml.highest_blocked = LKM_IVMODE;
639 spin_unlock(&lock->spinlock);
641 /* remove from list (including ref) */
642 list_del_init(&lock->bast_list);
643 dlm_lock_put(lock);
644 spin_unlock(&dlm->ast_lock);
646 mlog(0, "%s: res %.*s, Flush BAST for lock %u:%llu, "
647 "blocked %d, node %u\n",
648 dlm->name, res->lockname.len, res->lockname.name,
649 dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
650 dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
651 hi, lock->ml.node);
653 if (lock->ml.node != dlm->node_num) {
654 ret = dlm_send_proxy_bast(dlm, res, lock, hi);
655 if (ret < 0)
656 mlog_errno(ret);
657 } else
658 dlm_do_local_bast(dlm, res, lock, hi);
660 spin_lock(&dlm->ast_lock);
662 /* possible that another bast was queued while
663 * we were delivering the last one */
664 if (!list_empty(&lock->bast_list)) {
665 mlog(0, "%s: res %.*s, BAST queued while flushing last "
666 "one\n", dlm->name, res->lockname.len,
667 res->lockname.name);
668 } else
669 lock->bast_pending = 0;
671 /* drop the extra ref.
672 * this may drop it completely. */
673 dlm_lock_put(lock);
674 dlm_lockres_release_ast(dlm, res);
676 wake_up(&dlm->ast_wq);
677 spin_unlock(&dlm->ast_lock);
681 #define DLM_THREAD_TIMEOUT_MS (4 * 1000)
682 #define DLM_THREAD_MAX_DIRTY 100
683 #define DLM_THREAD_MAX_ASTS 10
685 static int dlm_thread(void *data)
687 struct dlm_lock_resource *res;
688 struct dlm_ctxt *dlm = data;
689 unsigned long timeout = msecs_to_jiffies(DLM_THREAD_TIMEOUT_MS);
691 mlog(0, "dlm thread running for %s...\n", dlm->name);
693 while (!kthread_should_stop()) {
694 int n = DLM_THREAD_MAX_DIRTY;
696 /* dlm_shutting_down is very point-in-time, but that
697 * doesn't matter as we'll just loop back around if we
698 * get false on the leading edge of a state
699 * transition. */
700 dlm_run_purge_list(dlm, dlm_shutting_down(dlm));
702 /* We really don't want to hold dlm->spinlock while
703 * calling dlm_shuffle_lists on each lockres that
704 * needs to have its queues adjusted and AST/BASTs
705 * run. So let's pull each entry off the dirty_list
706 * and drop dlm->spinlock ASAP. Once off the list,
707 * res->spinlock needs to be taken again to protect
708 * the queues while calling dlm_shuffle_lists. */
709 spin_lock(&dlm->spinlock);
710 while (!list_empty(&dlm->dirty_list)) {
711 int delay = 0;
712 res = list_entry(dlm->dirty_list.next,
713 struct dlm_lock_resource, dirty);
715 /* peel a lockres off, remove it from the list,
716 * unset the dirty flag and drop the dlm lock */
717 BUG_ON(!res);
718 dlm_lockres_get(res);
720 spin_lock(&res->spinlock);
721 /* We clear the DLM_LOCK_RES_DIRTY state once we shuffle lists below */
722 list_del_init(&res->dirty);
723 spin_unlock(&res->spinlock);
724 spin_unlock(&dlm->spinlock);
725 /* Drop dirty_list ref */
726 dlm_lockres_put(res);
728 /* lockres can be re-dirtied/re-added to the
729 * dirty_list in this gap, but that is ok */
731 spin_lock(&dlm->ast_lock);
732 spin_lock(&res->spinlock);
733 if (res->owner != dlm->node_num) {
734 __dlm_print_one_lock_resource(res);
735 mlog(ML_ERROR, "%s: inprog %d, mig %d, reco %d,"
736 " dirty %d\n", dlm->name,
737 !!(res->state & DLM_LOCK_RES_IN_PROGRESS),
738 !!(res->state & DLM_LOCK_RES_MIGRATING),
739 !!(res->state & DLM_LOCK_RES_RECOVERING),
740 !!(res->state & DLM_LOCK_RES_DIRTY));
742 BUG_ON(res->owner != dlm->node_num);
744 /* it is now ok to move lockreses in these states
745 * to the dirty list, assuming that they will only be
746 * dirty for a short while. */
747 BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
748 if (res->state & (DLM_LOCK_RES_IN_PROGRESS |
749 DLM_LOCK_RES_RECOVERING |
750 DLM_LOCK_RES_RECOVERY_WAITING)) {
751 /* move it to the tail and keep going */
752 res->state &= ~DLM_LOCK_RES_DIRTY;
753 spin_unlock(&res->spinlock);
754 spin_unlock(&dlm->ast_lock);
755 mlog(0, "%s: res %.*s, inprogress, delay list "
756 "shuffle, state %d\n", dlm->name,
757 res->lockname.len, res->lockname.name,
758 res->state);
759 delay = 1;
760 goto in_progress;
763 /* at this point the lockres is not migrating/
764 * recovering/in-progress. we have the lockres
765 * spinlock and do NOT have the dlm lock.
766 * safe to reserve/queue asts and run the lists. */
768 /* called while holding lockres lock */
769 dlm_shuffle_lists(dlm, res);
770 res->state &= ~DLM_LOCK_RES_DIRTY;
771 spin_unlock(&res->spinlock);
772 spin_unlock(&dlm->ast_lock);
774 dlm_lockres_calc_usage(dlm, res);
776 in_progress:
778 spin_lock(&dlm->spinlock);
779 /* if the lock was in-progress, stick
780 * it on the back of the list */
781 if (delay) {
782 spin_lock(&res->spinlock);
783 __dlm_dirty_lockres(dlm, res);
784 spin_unlock(&res->spinlock);
786 dlm_lockres_put(res);
788 /* unlikely, but we may need to give time to
789 * other tasks */
790 if (!--n) {
791 mlog(0, "%s: Throttling dlm thread\n",
792 dlm->name);
793 break;
797 spin_unlock(&dlm->spinlock);
798 dlm_flush_asts(dlm);
800 /* yield and continue right away if there is more work to do */
801 if (!n) {
802 cond_resched();
803 continue;
806 wait_event_interruptible_timeout(dlm->dlm_thread_wq,
807 !dlm_dirty_list_empty(dlm) ||
808 kthread_should_stop(),
809 timeout);
812 mlog(0, "quitting DLM thread\n");
813 return 0;