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ocfs2: calculate lockid hash values outside of the spinlock
[deliverable/linux.git] / fs / ocfs2 / dlm / dlmdomain.c
1 /* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
3 *
4 * dlmdomain.c
5 *
6 * defines domain join / leave apis
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 #include <linux/module.h>
28 #include <linux/types.h>
29 #include <linux/slab.h>
30 #include <linux/highmem.h>
31 #include <linux/utsname.h>
32 #include <linux/init.h>
33 #include <linux/spinlock.h>
34 #include <linux/delay.h>
35 #include <linux/err.h>
36
37 #include "cluster/heartbeat.h"
38 #include "cluster/nodemanager.h"
39 #include "cluster/tcp.h"
40
41 #include "dlmapi.h"
42 #include "dlmcommon.h"
43
44 #include "dlmdebug.h"
45 #include "dlmdomain.h"
46
47 #include "dlmver.h"
48
49 #define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_DOMAIN)
50 #include "cluster/masklog.h"
51
52 /*
53 *
54 * spinlock lock ordering: if multiple locks are needed, obey this ordering:
55 * dlm_domain_lock
56 * struct dlm_ctxt->spinlock
57 * struct dlm_lock_resource->spinlock
58 * struct dlm_ctxt->master_lock
59 * struct dlm_ctxt->ast_lock
60 * dlm_master_list_entry->spinlock
61 * dlm_lock->spinlock
62 *
63 */
64
65 spinlock_t dlm_domain_lock = SPIN_LOCK_UNLOCKED;
66 LIST_HEAD(dlm_domains);
67 static DECLARE_WAIT_QUEUE_HEAD(dlm_domain_events);
68
69 #define DLM_DOMAIN_BACKOFF_MS 200
70
71 static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data);
72 static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data);
73 static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data);
74 static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data);
75
76 static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm);
77
78 void __dlm_unhash_lockres(struct dlm_lock_resource *lockres)
79 {
80 hlist_del_init(&lockres->hash_node);
81 dlm_lockres_put(lockres);
82 }
83
84 void __dlm_insert_lockres(struct dlm_ctxt *dlm,
85 struct dlm_lock_resource *res)
86 {
87 struct hlist_head *bucket;
88 struct qstr *q;
89
90 assert_spin_locked(&dlm->spinlock);
91
92 q = &res->lockname;
93 bucket = &(dlm->lockres_hash[q->hash % DLM_HASH_BUCKETS]);
94
95 /* get a reference for our hashtable */
96 dlm_lockres_get(res);
97
98 hlist_add_head(&res->hash_node, bucket);
99 }
100
101 struct dlm_lock_resource * __dlm_lookup_lockres(struct dlm_ctxt *dlm,
102 const char *name,
103 unsigned int len,
104 unsigned int hash)
105 {
106 struct hlist_node *iter;
107 struct dlm_lock_resource *tmpres=NULL;
108 struct hlist_head *bucket;
109
110 mlog_entry("%.*s\n", len, name);
111
112 assert_spin_locked(&dlm->spinlock);
113
114 bucket = &(dlm->lockres_hash[hash % DLM_HASH_BUCKETS]);
115
116 /* check for pre-existing lock */
117 hlist_for_each(iter, bucket) {
118 tmpres = hlist_entry(iter, struct dlm_lock_resource, hash_node);
119 if (tmpres->lockname.len == len &&
120 memcmp(tmpres->lockname.name, name, len) == 0) {
121 dlm_lockres_get(tmpres);
122 break;
123 }
124
125 tmpres = NULL;
126 }
127 return tmpres;
128 }
129
130 struct dlm_lock_resource * dlm_lookup_lockres(struct dlm_ctxt *dlm,
131 const char *name,
132 unsigned int len)
133 {
134 struct dlm_lock_resource *res;
135 unsigned int hash = dlm_lockid_hash(name, len);
136
137 spin_lock(&dlm->spinlock);
138 res = __dlm_lookup_lockres(dlm, name, len, hash);
139 spin_unlock(&dlm->spinlock);
140 return res;
141 }
142
143 static struct dlm_ctxt * __dlm_lookup_domain_full(const char *domain, int len)
144 {
145 struct dlm_ctxt *tmp = NULL;
146 struct list_head *iter;
147
148 assert_spin_locked(&dlm_domain_lock);
149
150 /* tmp->name here is always NULL terminated,
151 * but domain may not be! */
152 list_for_each(iter, &dlm_domains) {
153 tmp = list_entry (iter, struct dlm_ctxt, list);
154 if (strlen(tmp->name) == len &&
155 memcmp(tmp->name, domain, len)==0)
156 break;
157 tmp = NULL;
158 }
159
160 return tmp;
161 }
162
163 /* For null terminated domain strings ONLY */
164 static struct dlm_ctxt * __dlm_lookup_domain(const char *domain)
165 {
166 assert_spin_locked(&dlm_domain_lock);
167
168 return __dlm_lookup_domain_full(domain, strlen(domain));
169 }
170
171
172 /* returns true on one of two conditions:
173 * 1) the domain does not exist
174 * 2) the domain exists and it's state is "joined" */
175 static int dlm_wait_on_domain_helper(const char *domain)
176 {
177 int ret = 0;
178 struct dlm_ctxt *tmp = NULL;
179
180 spin_lock(&dlm_domain_lock);
181
182 tmp = __dlm_lookup_domain(domain);
183 if (!tmp)
184 ret = 1;
185 else if (tmp->dlm_state == DLM_CTXT_JOINED)
186 ret = 1;
187
188 spin_unlock(&dlm_domain_lock);
189 return ret;
190 }
191
192 static void dlm_free_ctxt_mem(struct dlm_ctxt *dlm)
193 {
194 if (dlm->lockres_hash)
195 free_page((unsigned long) dlm->lockres_hash);
196
197 if (dlm->name)
198 kfree(dlm->name);
199
200 kfree(dlm);
201 }
202
203 /* A little strange - this function will be called while holding
204 * dlm_domain_lock and is expected to be holding it on the way out. We
205 * will however drop and reacquire it multiple times */
206 static void dlm_ctxt_release(struct kref *kref)
207 {
208 struct dlm_ctxt *dlm;
209
210 dlm = container_of(kref, struct dlm_ctxt, dlm_refs);
211
212 BUG_ON(dlm->num_joins);
213 BUG_ON(dlm->dlm_state == DLM_CTXT_JOINED);
214
215 /* we may still be in the list if we hit an error during join. */
216 list_del_init(&dlm->list);
217
218 spin_unlock(&dlm_domain_lock);
219
220 mlog(0, "freeing memory from domain %s\n", dlm->name);
221
222 wake_up(&dlm_domain_events);
223
224 dlm_free_ctxt_mem(dlm);
225
226 spin_lock(&dlm_domain_lock);
227 }
228
229 void dlm_put(struct dlm_ctxt *dlm)
230 {
231 spin_lock(&dlm_domain_lock);
232 kref_put(&dlm->dlm_refs, dlm_ctxt_release);
233 spin_unlock(&dlm_domain_lock);
234 }
235
236 static void __dlm_get(struct dlm_ctxt *dlm)
237 {
238 kref_get(&dlm->dlm_refs);
239 }
240
241 /* given a questionable reference to a dlm object, gets a reference if
242 * it can find it in the list, otherwise returns NULL in which case
243 * you shouldn't trust your pointer. */
244 struct dlm_ctxt *dlm_grab(struct dlm_ctxt *dlm)
245 {
246 struct list_head *iter;
247 struct dlm_ctxt *target = NULL;
248
249 spin_lock(&dlm_domain_lock);
250
251 list_for_each(iter, &dlm_domains) {
252 target = list_entry (iter, struct dlm_ctxt, list);
253
254 if (target == dlm) {
255 __dlm_get(target);
256 break;
257 }
258
259 target = NULL;
260 }
261
262 spin_unlock(&dlm_domain_lock);
263
264 return target;
265 }
266
267 int dlm_domain_fully_joined(struct dlm_ctxt *dlm)
268 {
269 int ret;
270
271 spin_lock(&dlm_domain_lock);
272 ret = (dlm->dlm_state == DLM_CTXT_JOINED) ||
273 (dlm->dlm_state == DLM_CTXT_IN_SHUTDOWN);
274 spin_unlock(&dlm_domain_lock);
275
276 return ret;
277 }
278
279 static void dlm_complete_dlm_shutdown(struct dlm_ctxt *dlm)
280 {
281 dlm_unregister_domain_handlers(dlm);
282 dlm_complete_thread(dlm);
283 dlm_complete_recovery_thread(dlm);
284
285 /* We've left the domain. Now we can take ourselves out of the
286 * list and allow the kref stuff to help us free the
287 * memory. */
288 spin_lock(&dlm_domain_lock);
289 list_del_init(&dlm->list);
290 spin_unlock(&dlm_domain_lock);
291
292 /* Wake up anyone waiting for us to remove this domain */
293 wake_up(&dlm_domain_events);
294 }
295
296 static void dlm_migrate_all_locks(struct dlm_ctxt *dlm)
297 {
298 int i;
299 struct dlm_lock_resource *res;
300
301 mlog(0, "Migrating locks from domain %s\n", dlm->name);
302 restart:
303 spin_lock(&dlm->spinlock);
304 for (i = 0; i < DLM_HASH_BUCKETS; i++) {
305 while (!hlist_empty(&dlm->lockres_hash[i])) {
306 res = hlist_entry(dlm->lockres_hash[i].first,
307 struct dlm_lock_resource, hash_node);
308 /* need reference when manually grabbing lockres */
309 dlm_lockres_get(res);
310 /* this should unhash the lockres
311 * and exit with dlm->spinlock */
312 mlog(0, "purging res=%p\n", res);
313 if (dlm_lockres_is_dirty(dlm, res)) {
314 /* HACK! this should absolutely go.
315 * need to figure out why some empty
316 * lockreses are still marked dirty */
317 mlog(ML_ERROR, "lockres %.*s dirty!\n",
318 res->lockname.len, res->lockname.name);
319
320 spin_unlock(&dlm->spinlock);
321 dlm_kick_thread(dlm, res);
322 wait_event(dlm->ast_wq, !dlm_lockres_is_dirty(dlm, res));
323 dlm_lockres_put(res);
324 goto restart;
325 }
326 dlm_purge_lockres(dlm, res);
327 dlm_lockres_put(res);
328 }
329 }
330 spin_unlock(&dlm->spinlock);
331
332 mlog(0, "DONE Migrating locks from domain %s\n", dlm->name);
333 }
334
335 static int dlm_no_joining_node(struct dlm_ctxt *dlm)
336 {
337 int ret;
338
339 spin_lock(&dlm->spinlock);
340 ret = dlm->joining_node == DLM_LOCK_RES_OWNER_UNKNOWN;
341 spin_unlock(&dlm->spinlock);
342
343 return ret;
344 }
345
346 static void dlm_mark_domain_leaving(struct dlm_ctxt *dlm)
347 {
348 /* Yikes, a double spinlock! I need domain_lock for the dlm
349 * state and the dlm spinlock for join state... Sorry! */
350 again:
351 spin_lock(&dlm_domain_lock);
352 spin_lock(&dlm->spinlock);
353
354 if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
355 mlog(0, "Node %d is joining, we wait on it.\n",
356 dlm->joining_node);
357 spin_unlock(&dlm->spinlock);
358 spin_unlock(&dlm_domain_lock);
359
360 wait_event(dlm->dlm_join_events, dlm_no_joining_node(dlm));
361 goto again;
362 }
363
364 dlm->dlm_state = DLM_CTXT_LEAVING;
365 spin_unlock(&dlm->spinlock);
366 spin_unlock(&dlm_domain_lock);
367 }
368
369 static void __dlm_print_nodes(struct dlm_ctxt *dlm)
370 {
371 int node = -1;
372
373 assert_spin_locked(&dlm->spinlock);
374
375 mlog(ML_NOTICE, "Nodes in my domain (\"%s\"):\n", dlm->name);
376
377 while ((node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES,
378 node + 1)) < O2NM_MAX_NODES) {
379 mlog(ML_NOTICE, " node %d\n", node);
380 }
381 }
382
383 static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data)
384 {
385 struct dlm_ctxt *dlm = data;
386 unsigned int node;
387 struct dlm_exit_domain *exit_msg = (struct dlm_exit_domain *) msg->buf;
388
389 mlog_entry("%p %u %p", msg, len, data);
390
391 if (!dlm_grab(dlm))
392 return 0;
393
394 node = exit_msg->node_idx;
395
396 mlog(0, "Node %u leaves domain %s\n", node, dlm->name);
397
398 spin_lock(&dlm->spinlock);
399 clear_bit(node, dlm->domain_map);
400 __dlm_print_nodes(dlm);
401
402 /* notify anything attached to the heartbeat events */
403 dlm_hb_event_notify_attached(dlm, node, 0);
404
405 spin_unlock(&dlm->spinlock);
406
407 dlm_put(dlm);
408
409 return 0;
410 }
411
412 static int dlm_send_one_domain_exit(struct dlm_ctxt *dlm,
413 unsigned int node)
414 {
415 int status;
416 struct dlm_exit_domain leave_msg;
417
418 mlog(0, "Asking node %u if we can leave the domain %s me = %u\n",
419 node, dlm->name, dlm->node_num);
420
421 memset(&leave_msg, 0, sizeof(leave_msg));
422 leave_msg.node_idx = dlm->node_num;
423
424 status = o2net_send_message(DLM_EXIT_DOMAIN_MSG, dlm->key,
425 &leave_msg, sizeof(leave_msg), node,
426 NULL);
427
428 mlog(0, "status return %d from o2net_send_message\n", status);
429
430 return status;
431 }
432
433
434 static void dlm_leave_domain(struct dlm_ctxt *dlm)
435 {
436 int node, clear_node, status;
437
438 /* At this point we've migrated away all our locks and won't
439 * accept mastership of new ones. The dlm is responsible for
440 * almost nothing now. We make sure not to confuse any joining
441 * nodes and then commence shutdown procedure. */
442
443 spin_lock(&dlm->spinlock);
444 /* Clear ourselves from the domain map */
445 clear_bit(dlm->node_num, dlm->domain_map);
446 while ((node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES,
447 0)) < O2NM_MAX_NODES) {
448 /* Drop the dlm spinlock. This is safe wrt the domain_map.
449 * -nodes cannot be added now as the
450 * query_join_handlers knows to respond with OK_NO_MAP
451 * -we catch the right network errors if a node is
452 * removed from the map while we're sending him the
453 * exit message. */
454 spin_unlock(&dlm->spinlock);
455
456 clear_node = 1;
457
458 status = dlm_send_one_domain_exit(dlm, node);
459 if (status < 0 &&
460 status != -ENOPROTOOPT &&
461 status != -ENOTCONN) {
462 mlog(ML_NOTICE, "Error %d sending domain exit message "
463 "to node %d\n", status, node);
464
465 /* Not sure what to do here but lets sleep for
466 * a bit in case this was a transient
467 * error... */
468 msleep(DLM_DOMAIN_BACKOFF_MS);
469 clear_node = 0;
470 }
471
472 spin_lock(&dlm->spinlock);
473 /* If we're not clearing the node bit then we intend
474 * to loop back around to try again. */
475 if (clear_node)
476 clear_bit(node, dlm->domain_map);
477 }
478 spin_unlock(&dlm->spinlock);
479 }
480
481 int dlm_joined(struct dlm_ctxt *dlm)
482 {
483 int ret = 0;
484
485 spin_lock(&dlm_domain_lock);
486
487 if (dlm->dlm_state == DLM_CTXT_JOINED)
488 ret = 1;
489
490 spin_unlock(&dlm_domain_lock);
491
492 return ret;
493 }
494
495 int dlm_shutting_down(struct dlm_ctxt *dlm)
496 {
497 int ret = 0;
498
499 spin_lock(&dlm_domain_lock);
500
501 if (dlm->dlm_state == DLM_CTXT_IN_SHUTDOWN)
502 ret = 1;
503
504 spin_unlock(&dlm_domain_lock);
505
506 return ret;
507 }
508
509 void dlm_unregister_domain(struct dlm_ctxt *dlm)
510 {
511 int leave = 0;
512
513 spin_lock(&dlm_domain_lock);
514 BUG_ON(dlm->dlm_state != DLM_CTXT_JOINED);
515 BUG_ON(!dlm->num_joins);
516
517 dlm->num_joins--;
518 if (!dlm->num_joins) {
519 /* We mark it "in shutdown" now so new register
520 * requests wait until we've completely left the
521 * domain. Don't use DLM_CTXT_LEAVING yet as we still
522 * want new domain joins to communicate with us at
523 * least until we've completed migration of our
524 * resources. */
525 dlm->dlm_state = DLM_CTXT_IN_SHUTDOWN;
526 leave = 1;
527 }
528 spin_unlock(&dlm_domain_lock);
529
530 if (leave) {
531 mlog(0, "shutting down domain %s\n", dlm->name);
532
533 /* We changed dlm state, notify the thread */
534 dlm_kick_thread(dlm, NULL);
535
536 dlm_migrate_all_locks(dlm);
537 dlm_mark_domain_leaving(dlm);
538 dlm_leave_domain(dlm);
539 dlm_complete_dlm_shutdown(dlm);
540 }
541 dlm_put(dlm);
542 }
543 EXPORT_SYMBOL_GPL(dlm_unregister_domain);
544
545 static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data)
546 {
547 struct dlm_query_join_request *query;
548 enum dlm_query_join_response response;
549 struct dlm_ctxt *dlm = NULL;
550
551 query = (struct dlm_query_join_request *) msg->buf;
552
553 mlog(0, "node %u wants to join domain %s\n", query->node_idx,
554 query->domain);
555
556 /*
557 * If heartbeat doesn't consider the node live, tell it
558 * to back off and try again. This gives heartbeat a chance
559 * to catch up.
560 */
561 if (!o2hb_check_node_heartbeating(query->node_idx)) {
562 mlog(0, "node %u is not in our live map yet\n",
563 query->node_idx);
564
565 response = JOIN_DISALLOW;
566 goto respond;
567 }
568
569 response = JOIN_OK_NO_MAP;
570
571 spin_lock(&dlm_domain_lock);
572 dlm = __dlm_lookup_domain_full(query->domain, query->name_len);
573 /* Once the dlm ctxt is marked as leaving then we don't want
574 * to be put in someone's domain map.
575 * Also, explicitly disallow joining at certain troublesome
576 * times (ie. during recovery). */
577 if (dlm && dlm->dlm_state != DLM_CTXT_LEAVING) {
578 int bit = query->node_idx;
579 spin_lock(&dlm->spinlock);
580
581 if (dlm->dlm_state == DLM_CTXT_NEW &&
582 dlm->joining_node == DLM_LOCK_RES_OWNER_UNKNOWN) {
583 /*If this is a brand new context and we
584 * haven't started our join process yet, then
585 * the other node won the race. */
586 response = JOIN_OK_NO_MAP;
587 } else if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
588 /* Disallow parallel joins. */
589 response = JOIN_DISALLOW;
590 } else if (dlm->reco.state & DLM_RECO_STATE_ACTIVE) {
591 mlog(ML_NOTICE, "node %u trying to join, but recovery "
592 "is ongoing.\n", bit);
593 response = JOIN_DISALLOW;
594 } else if (test_bit(bit, dlm->recovery_map)) {
595 mlog(ML_NOTICE, "node %u trying to join, but it "
596 "still needs recovery.\n", bit);
597 response = JOIN_DISALLOW;
598 } else if (test_bit(bit, dlm->domain_map)) {
599 mlog(ML_NOTICE, "node %u trying to join, but it "
600 "is still in the domain! needs recovery?\n",
601 bit);
602 response = JOIN_DISALLOW;
603 } else {
604 /* Alright we're fully a part of this domain
605 * so we keep some state as to who's joining
606 * and indicate to him that needs to be fixed
607 * up. */
608 response = JOIN_OK;
609 __dlm_set_joining_node(dlm, query->node_idx);
610 }
611
612 spin_unlock(&dlm->spinlock);
613 }
614 spin_unlock(&dlm_domain_lock);
615
616 respond:
617 mlog(0, "We respond with %u\n", response);
618
619 return response;
620 }
621
622 static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data)
623 {
624 struct dlm_assert_joined *assert;
625 struct dlm_ctxt *dlm = NULL;
626
627 assert = (struct dlm_assert_joined *) msg->buf;
628
629 mlog(0, "node %u asserts join on domain %s\n", assert->node_idx,
630 assert->domain);
631
632 spin_lock(&dlm_domain_lock);
633 dlm = __dlm_lookup_domain_full(assert->domain, assert->name_len);
634 /* XXX should we consider no dlm ctxt an error? */
635 if (dlm) {
636 spin_lock(&dlm->spinlock);
637
638 /* Alright, this node has officially joined our
639 * domain. Set him in the map and clean up our
640 * leftover join state. */
641 BUG_ON(dlm->joining_node != assert->node_idx);
642 set_bit(assert->node_idx, dlm->domain_map);
643 __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
644
645 __dlm_print_nodes(dlm);
646
647 /* notify anything attached to the heartbeat events */
648 dlm_hb_event_notify_attached(dlm, assert->node_idx, 1);
649
650 spin_unlock(&dlm->spinlock);
651 }
652 spin_unlock(&dlm_domain_lock);
653
654 return 0;
655 }
656
657 static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data)
658 {
659 struct dlm_cancel_join *cancel;
660 struct dlm_ctxt *dlm = NULL;
661
662 cancel = (struct dlm_cancel_join *) msg->buf;
663
664 mlog(0, "node %u cancels join on domain %s\n", cancel->node_idx,
665 cancel->domain);
666
667 spin_lock(&dlm_domain_lock);
668 dlm = __dlm_lookup_domain_full(cancel->domain, cancel->name_len);
669
670 if (dlm) {
671 spin_lock(&dlm->spinlock);
672
673 /* Yikes, this guy wants to cancel his join. No
674 * problem, we simply cleanup our join state. */
675 BUG_ON(dlm->joining_node != cancel->node_idx);
676 __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
677
678 spin_unlock(&dlm->spinlock);
679 }
680 spin_unlock(&dlm_domain_lock);
681
682 return 0;
683 }
684
685 static int dlm_send_one_join_cancel(struct dlm_ctxt *dlm,
686 unsigned int node)
687 {
688 int status;
689 struct dlm_cancel_join cancel_msg;
690
691 memset(&cancel_msg, 0, sizeof(cancel_msg));
692 cancel_msg.node_idx = dlm->node_num;
693 cancel_msg.name_len = strlen(dlm->name);
694 memcpy(cancel_msg.domain, dlm->name, cancel_msg.name_len);
695
696 status = o2net_send_message(DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
697 &cancel_msg, sizeof(cancel_msg), node,
698 NULL);
699 if (status < 0) {
700 mlog_errno(status);
701 goto bail;
702 }
703
704 bail:
705 return status;
706 }
707
708 /* map_size should be in bytes. */
709 static int dlm_send_join_cancels(struct dlm_ctxt *dlm,
710 unsigned long *node_map,
711 unsigned int map_size)
712 {
713 int status, tmpstat;
714 unsigned int node;
715
716 if (map_size != (BITS_TO_LONGS(O2NM_MAX_NODES) *
717 sizeof(unsigned long))) {
718 mlog(ML_ERROR,
719 "map_size %u != BITS_TO_LONGS(O2NM_MAX_NODES) %u\n",
720 map_size, BITS_TO_LONGS(O2NM_MAX_NODES));
721 return -EINVAL;
722 }
723
724 status = 0;
725 node = -1;
726 while ((node = find_next_bit(node_map, O2NM_MAX_NODES,
727 node + 1)) < O2NM_MAX_NODES) {
728 if (node == dlm->node_num)
729 continue;
730
731 tmpstat = dlm_send_one_join_cancel(dlm, node);
732 if (tmpstat) {
733 mlog(ML_ERROR, "Error return %d cancelling join on "
734 "node %d\n", tmpstat, node);
735 if (!status)
736 status = tmpstat;
737 }
738 }
739
740 if (status)
741 mlog_errno(status);
742 return status;
743 }
744
745 static int dlm_request_join(struct dlm_ctxt *dlm,
746 int node,
747 enum dlm_query_join_response *response)
748 {
749 int status, retval;
750 struct dlm_query_join_request join_msg;
751
752 mlog(0, "querying node %d\n", node);
753
754 memset(&join_msg, 0, sizeof(join_msg));
755 join_msg.node_idx = dlm->node_num;
756 join_msg.name_len = strlen(dlm->name);
757 memcpy(join_msg.domain, dlm->name, join_msg.name_len);
758
759 status = o2net_send_message(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY, &join_msg,
760 sizeof(join_msg), node, &retval);
761 if (status < 0 && status != -ENOPROTOOPT) {
762 mlog_errno(status);
763 goto bail;
764 }
765
766 /* -ENOPROTOOPT from the net code means the other side isn't
767 listening for our message type -- that's fine, it means
768 his dlm isn't up, so we can consider him a 'yes' but not
769 joined into the domain. */
770 if (status == -ENOPROTOOPT) {
771 status = 0;
772 *response = JOIN_OK_NO_MAP;
773 } else if (retval == JOIN_DISALLOW ||
774 retval == JOIN_OK ||
775 retval == JOIN_OK_NO_MAP) {
776 *response = retval;
777 } else {
778 status = -EINVAL;
779 mlog(ML_ERROR, "invalid response %d from node %u\n", retval,
780 node);
781 }
782
783 mlog(0, "status %d, node %d response is %d\n", status, node,
784 *response);
785
786 bail:
787 return status;
788 }
789
790 static int dlm_send_one_join_assert(struct dlm_ctxt *dlm,
791 unsigned int node)
792 {
793 int status;
794 struct dlm_assert_joined assert_msg;
795
796 mlog(0, "Sending join assert to node %u\n", node);
797
798 memset(&assert_msg, 0, sizeof(assert_msg));
799 assert_msg.node_idx = dlm->node_num;
800 assert_msg.name_len = strlen(dlm->name);
801 memcpy(assert_msg.domain, dlm->name, assert_msg.name_len);
802
803 status = o2net_send_message(DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
804 &assert_msg, sizeof(assert_msg), node,
805 NULL);
806 if (status < 0)
807 mlog_errno(status);
808
809 return status;
810 }
811
812 static void dlm_send_join_asserts(struct dlm_ctxt *dlm,
813 unsigned long *node_map)
814 {
815 int status, node, live;
816
817 status = 0;
818 node = -1;
819 while ((node = find_next_bit(node_map, O2NM_MAX_NODES,
820 node + 1)) < O2NM_MAX_NODES) {
821 if (node == dlm->node_num)
822 continue;
823
824 do {
825 /* It is very important that this message be
826 * received so we spin until either the node
827 * has died or it gets the message. */
828 status = dlm_send_one_join_assert(dlm, node);
829
830 spin_lock(&dlm->spinlock);
831 live = test_bit(node, dlm->live_nodes_map);
832 spin_unlock(&dlm->spinlock);
833
834 if (status) {
835 mlog(ML_ERROR, "Error return %d asserting "
836 "join on node %d\n", status, node);
837
838 /* give us some time between errors... */
839 if (live)
840 msleep(DLM_DOMAIN_BACKOFF_MS);
841 }
842 } while (status && live);
843 }
844 }
845
846 struct domain_join_ctxt {
847 unsigned long live_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
848 unsigned long yes_resp_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
849 };
850
851 static int dlm_should_restart_join(struct dlm_ctxt *dlm,
852 struct domain_join_ctxt *ctxt,
853 enum dlm_query_join_response response)
854 {
855 int ret;
856
857 if (response == JOIN_DISALLOW) {
858 mlog(0, "Latest response of disallow -- should restart\n");
859 return 1;
860 }
861
862 spin_lock(&dlm->spinlock);
863 /* For now, we restart the process if the node maps have
864 * changed at all */
865 ret = memcmp(ctxt->live_map, dlm->live_nodes_map,
866 sizeof(dlm->live_nodes_map));
867 spin_unlock(&dlm->spinlock);
868
869 if (ret)
870 mlog(0, "Node maps changed -- should restart\n");
871
872 return ret;
873 }
874
875 static int dlm_try_to_join_domain(struct dlm_ctxt *dlm)
876 {
877 int status = 0, tmpstat, node;
878 struct domain_join_ctxt *ctxt;
879 enum dlm_query_join_response response;
880
881 mlog_entry("%p", dlm);
882
883 ctxt = kcalloc(1, sizeof(*ctxt), GFP_KERNEL);
884 if (!ctxt) {
885 status = -ENOMEM;
886 mlog_errno(status);
887 goto bail;
888 }
889
890 /* group sem locking should work for us here -- we're already
891 * registered for heartbeat events so filling this should be
892 * atomic wrt getting those handlers called. */
893 o2hb_fill_node_map(dlm->live_nodes_map, sizeof(dlm->live_nodes_map));
894
895 spin_lock(&dlm->spinlock);
896 memcpy(ctxt->live_map, dlm->live_nodes_map, sizeof(ctxt->live_map));
897
898 __dlm_set_joining_node(dlm, dlm->node_num);
899
900 spin_unlock(&dlm->spinlock);
901
902 node = -1;
903 while ((node = find_next_bit(ctxt->live_map, O2NM_MAX_NODES,
904 node + 1)) < O2NM_MAX_NODES) {
905 if (node == dlm->node_num)
906 continue;
907
908 status = dlm_request_join(dlm, node, &response);
909 if (status < 0) {
910 mlog_errno(status);
911 goto bail;
912 }
913
914 /* Ok, either we got a response or the node doesn't have a
915 * dlm up. */
916 if (response == JOIN_OK)
917 set_bit(node, ctxt->yes_resp_map);
918
919 if (dlm_should_restart_join(dlm, ctxt, response)) {
920 status = -EAGAIN;
921 goto bail;
922 }
923 }
924
925 mlog(0, "Yay, done querying nodes!\n");
926
927 /* Yay, everyone agree's we can join the domain. My domain is
928 * comprised of all nodes who were put in the
929 * yes_resp_map. Copy that into our domain map and send a join
930 * assert message to clean up everyone elses state. */
931 spin_lock(&dlm->spinlock);
932 memcpy(dlm->domain_map, ctxt->yes_resp_map,
933 sizeof(ctxt->yes_resp_map));
934 set_bit(dlm->node_num, dlm->domain_map);
935 spin_unlock(&dlm->spinlock);
936
937 dlm_send_join_asserts(dlm, ctxt->yes_resp_map);
938
939 /* Joined state *must* be set before the joining node
940 * information, otherwise the query_join handler may read no
941 * current joiner but a state of NEW and tell joining nodes
942 * we're not in the domain. */
943 spin_lock(&dlm_domain_lock);
944 dlm->dlm_state = DLM_CTXT_JOINED;
945 dlm->num_joins++;
946 spin_unlock(&dlm_domain_lock);
947
948 bail:
949 spin_lock(&dlm->spinlock);
950 __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
951 if (!status)
952 __dlm_print_nodes(dlm);
953 spin_unlock(&dlm->spinlock);
954
955 if (ctxt) {
956 /* Do we need to send a cancel message to any nodes? */
957 if (status < 0) {
958 tmpstat = dlm_send_join_cancels(dlm,
959 ctxt->yes_resp_map,
960 sizeof(ctxt->yes_resp_map));
961 if (tmpstat < 0)
962 mlog_errno(tmpstat);
963 }
964 kfree(ctxt);
965 }
966
967 mlog(0, "returning %d\n", status);
968 return status;
969 }
970
971 static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm)
972 {
973 o2hb_unregister_callback(&dlm->dlm_hb_up);
974 o2hb_unregister_callback(&dlm->dlm_hb_down);
975 o2net_unregister_handler_list(&dlm->dlm_domain_handlers);
976 }
977
978 static int dlm_register_domain_handlers(struct dlm_ctxt *dlm)
979 {
980 int status;
981
982 mlog(0, "registering handlers.\n");
983
984 o2hb_setup_callback(&dlm->dlm_hb_down, O2HB_NODE_DOWN_CB,
985 dlm_hb_node_down_cb, dlm, DLM_HB_NODE_DOWN_PRI);
986 status = o2hb_register_callback(&dlm->dlm_hb_down);
987 if (status)
988 goto bail;
989
990 o2hb_setup_callback(&dlm->dlm_hb_up, O2HB_NODE_UP_CB,
991 dlm_hb_node_up_cb, dlm, DLM_HB_NODE_UP_PRI);
992 status = o2hb_register_callback(&dlm->dlm_hb_up);
993 if (status)
994 goto bail;
995
996 status = o2net_register_handler(DLM_MASTER_REQUEST_MSG, dlm->key,
997 sizeof(struct dlm_master_request),
998 dlm_master_request_handler,
999 dlm, &dlm->dlm_domain_handlers);
1000 if (status)
1001 goto bail;
1002
1003 status = o2net_register_handler(DLM_ASSERT_MASTER_MSG, dlm->key,
1004 sizeof(struct dlm_assert_master),
1005 dlm_assert_master_handler,
1006 dlm, &dlm->dlm_domain_handlers);
1007 if (status)
1008 goto bail;
1009
1010 status = o2net_register_handler(DLM_CREATE_LOCK_MSG, dlm->key,
1011 sizeof(struct dlm_create_lock),
1012 dlm_create_lock_handler,
1013 dlm, &dlm->dlm_domain_handlers);
1014 if (status)
1015 goto bail;
1016
1017 status = o2net_register_handler(DLM_CONVERT_LOCK_MSG, dlm->key,
1018 DLM_CONVERT_LOCK_MAX_LEN,
1019 dlm_convert_lock_handler,
1020 dlm, &dlm->dlm_domain_handlers);
1021 if (status)
1022 goto bail;
1023
1024 status = o2net_register_handler(DLM_UNLOCK_LOCK_MSG, dlm->key,
1025 DLM_UNLOCK_LOCK_MAX_LEN,
1026 dlm_unlock_lock_handler,
1027 dlm, &dlm->dlm_domain_handlers);
1028 if (status)
1029 goto bail;
1030
1031 status = o2net_register_handler(DLM_PROXY_AST_MSG, dlm->key,
1032 DLM_PROXY_AST_MAX_LEN,
1033 dlm_proxy_ast_handler,
1034 dlm, &dlm->dlm_domain_handlers);
1035 if (status)
1036 goto bail;
1037
1038 status = o2net_register_handler(DLM_EXIT_DOMAIN_MSG, dlm->key,
1039 sizeof(struct dlm_exit_domain),
1040 dlm_exit_domain_handler,
1041 dlm, &dlm->dlm_domain_handlers);
1042 if (status)
1043 goto bail;
1044
1045 status = o2net_register_handler(DLM_MIGRATE_REQUEST_MSG, dlm->key,
1046 sizeof(struct dlm_migrate_request),
1047 dlm_migrate_request_handler,
1048 dlm, &dlm->dlm_domain_handlers);
1049 if (status)
1050 goto bail;
1051
1052 status = o2net_register_handler(DLM_MIG_LOCKRES_MSG, dlm->key,
1053 DLM_MIG_LOCKRES_MAX_LEN,
1054 dlm_mig_lockres_handler,
1055 dlm, &dlm->dlm_domain_handlers);
1056 if (status)
1057 goto bail;
1058
1059 status = o2net_register_handler(DLM_MASTER_REQUERY_MSG, dlm->key,
1060 sizeof(struct dlm_master_requery),
1061 dlm_master_requery_handler,
1062 dlm, &dlm->dlm_domain_handlers);
1063 if (status)
1064 goto bail;
1065
1066 status = o2net_register_handler(DLM_LOCK_REQUEST_MSG, dlm->key,
1067 sizeof(struct dlm_lock_request),
1068 dlm_request_all_locks_handler,
1069 dlm, &dlm->dlm_domain_handlers);
1070 if (status)
1071 goto bail;
1072
1073 status = o2net_register_handler(DLM_RECO_DATA_DONE_MSG, dlm->key,
1074 sizeof(struct dlm_reco_data_done),
1075 dlm_reco_data_done_handler,
1076 dlm, &dlm->dlm_domain_handlers);
1077 if (status)
1078 goto bail;
1079
1080 status = o2net_register_handler(DLM_BEGIN_RECO_MSG, dlm->key,
1081 sizeof(struct dlm_begin_reco),
1082 dlm_begin_reco_handler,
1083 dlm, &dlm->dlm_domain_handlers);
1084 if (status)
1085 goto bail;
1086
1087 status = o2net_register_handler(DLM_FINALIZE_RECO_MSG, dlm->key,
1088 sizeof(struct dlm_finalize_reco),
1089 dlm_finalize_reco_handler,
1090 dlm, &dlm->dlm_domain_handlers);
1091 if (status)
1092 goto bail;
1093
1094 bail:
1095 if (status)
1096 dlm_unregister_domain_handlers(dlm);
1097
1098 return status;
1099 }
1100
1101 static int dlm_join_domain(struct dlm_ctxt *dlm)
1102 {
1103 int status;
1104
1105 BUG_ON(!dlm);
1106
1107 mlog(0, "Join domain %s\n", dlm->name);
1108
1109 status = dlm_register_domain_handlers(dlm);
1110 if (status) {
1111 mlog_errno(status);
1112 goto bail;
1113 }
1114
1115 status = dlm_launch_thread(dlm);
1116 if (status < 0) {
1117 mlog_errno(status);
1118 goto bail;
1119 }
1120
1121 status = dlm_launch_recovery_thread(dlm);
1122 if (status < 0) {
1123 mlog_errno(status);
1124 goto bail;
1125 }
1126
1127 do {
1128 unsigned int backoff;
1129 status = dlm_try_to_join_domain(dlm);
1130
1131 /* If we're racing another node to the join, then we
1132 * need to back off temporarily and let them
1133 * complete. */
1134 if (status == -EAGAIN) {
1135 if (signal_pending(current)) {
1136 status = -ERESTARTSYS;
1137 goto bail;
1138 }
1139
1140 /*
1141 * <chip> After you!
1142 * <dale> No, after you!
1143 * <chip> I insist!
1144 * <dale> But you first!
1145 * ...
1146 */
1147 backoff = (unsigned int)(jiffies & 0x3);
1148 backoff *= DLM_DOMAIN_BACKOFF_MS;
1149 mlog(0, "backoff %d\n", backoff);
1150 msleep(backoff);
1151 }
1152 } while (status == -EAGAIN);
1153
1154 if (status < 0) {
1155 mlog_errno(status);
1156 goto bail;
1157 }
1158
1159 status = 0;
1160 bail:
1161 wake_up(&dlm_domain_events);
1162
1163 if (status) {
1164 dlm_unregister_domain_handlers(dlm);
1165 dlm_complete_thread(dlm);
1166 dlm_complete_recovery_thread(dlm);
1167 }
1168
1169 return status;
1170 }
1171
1172 static struct dlm_ctxt *dlm_alloc_ctxt(const char *domain,
1173 u32 key)
1174 {
1175 int i;
1176 struct dlm_ctxt *dlm = NULL;
1177
1178 dlm = kcalloc(1, sizeof(*dlm), GFP_KERNEL);
1179 if (!dlm) {
1180 mlog_errno(-ENOMEM);
1181 goto leave;
1182 }
1183
1184 dlm->name = kmalloc(strlen(domain) + 1, GFP_KERNEL);
1185 if (dlm->name == NULL) {
1186 mlog_errno(-ENOMEM);
1187 kfree(dlm);
1188 dlm = NULL;
1189 goto leave;
1190 }
1191
1192 dlm->lockres_hash = (struct hlist_head *) __get_free_page(GFP_KERNEL);
1193 if (!dlm->lockres_hash) {
1194 mlog_errno(-ENOMEM);
1195 kfree(dlm->name);
1196 kfree(dlm);
1197 dlm = NULL;
1198 goto leave;
1199 }
1200
1201 for (i=0; i<DLM_HASH_BUCKETS; i++)
1202 INIT_HLIST_HEAD(&dlm->lockres_hash[i]);
1203
1204 strcpy(dlm->name, domain);
1205 dlm->key = key;
1206 dlm->node_num = o2nm_this_node();
1207
1208 spin_lock_init(&dlm->spinlock);
1209 spin_lock_init(&dlm->master_lock);
1210 spin_lock_init(&dlm->ast_lock);
1211 INIT_LIST_HEAD(&dlm->list);
1212 INIT_LIST_HEAD(&dlm->dirty_list);
1213 INIT_LIST_HEAD(&dlm->reco.resources);
1214 INIT_LIST_HEAD(&dlm->reco.received);
1215 INIT_LIST_HEAD(&dlm->reco.node_data);
1216 INIT_LIST_HEAD(&dlm->purge_list);
1217 INIT_LIST_HEAD(&dlm->dlm_domain_handlers);
1218 dlm->reco.state = 0;
1219
1220 INIT_LIST_HEAD(&dlm->pending_asts);
1221 INIT_LIST_HEAD(&dlm->pending_basts);
1222
1223 mlog(0, "dlm->recovery_map=%p, &(dlm->recovery_map[0])=%p\n",
1224 dlm->recovery_map, &(dlm->recovery_map[0]));
1225
1226 memset(dlm->recovery_map, 0, sizeof(dlm->recovery_map));
1227 memset(dlm->live_nodes_map, 0, sizeof(dlm->live_nodes_map));
1228 memset(dlm->domain_map, 0, sizeof(dlm->domain_map));
1229
1230 dlm->dlm_thread_task = NULL;
1231 dlm->dlm_reco_thread_task = NULL;
1232 init_waitqueue_head(&dlm->dlm_thread_wq);
1233 init_waitqueue_head(&dlm->dlm_reco_thread_wq);
1234 init_waitqueue_head(&dlm->reco.event);
1235 init_waitqueue_head(&dlm->ast_wq);
1236 init_waitqueue_head(&dlm->migration_wq);
1237 INIT_LIST_HEAD(&dlm->master_list);
1238 INIT_LIST_HEAD(&dlm->mle_hb_events);
1239
1240 dlm->joining_node = DLM_LOCK_RES_OWNER_UNKNOWN;
1241 init_waitqueue_head(&dlm->dlm_join_events);
1242
1243 dlm->reco.new_master = O2NM_INVALID_NODE_NUM;
1244 dlm->reco.dead_node = O2NM_INVALID_NODE_NUM;
1245 atomic_set(&dlm->local_resources, 0);
1246 atomic_set(&dlm->remote_resources, 0);
1247 atomic_set(&dlm->unknown_resources, 0);
1248
1249 spin_lock_init(&dlm->work_lock);
1250 INIT_LIST_HEAD(&dlm->work_list);
1251 INIT_WORK(&dlm->dispatched_work, dlm_dispatch_work, dlm);
1252
1253 kref_init(&dlm->dlm_refs);
1254 dlm->dlm_state = DLM_CTXT_NEW;
1255
1256 INIT_LIST_HEAD(&dlm->dlm_eviction_callbacks);
1257
1258 mlog(0, "context init: refcount %u\n",
1259 atomic_read(&dlm->dlm_refs.refcount));
1260
1261 leave:
1262 return dlm;
1263 }
1264
1265 /*
1266 * dlm_register_domain: one-time setup per "domain"
1267 */
1268 struct dlm_ctxt * dlm_register_domain(const char *domain,
1269 u32 key)
1270 {
1271 int ret;
1272 struct dlm_ctxt *dlm = NULL;
1273 struct dlm_ctxt *new_ctxt = NULL;
1274
1275 if (strlen(domain) > O2NM_MAX_NAME_LEN) {
1276 ret = -ENAMETOOLONG;
1277 mlog(ML_ERROR, "domain name length too long\n");
1278 goto leave;
1279 }
1280
1281 if (!o2hb_check_local_node_heartbeating()) {
1282 mlog(ML_ERROR, "the local node has not been configured, or is "
1283 "not heartbeating\n");
1284 ret = -EPROTO;
1285 goto leave;
1286 }
1287
1288 mlog(0, "register called for domain \"%s\"\n", domain);
1289
1290 retry:
1291 dlm = NULL;
1292 if (signal_pending(current)) {
1293 ret = -ERESTARTSYS;
1294 mlog_errno(ret);
1295 goto leave;
1296 }
1297
1298 spin_lock(&dlm_domain_lock);
1299
1300 dlm = __dlm_lookup_domain(domain);
1301 if (dlm) {
1302 if (dlm->dlm_state != DLM_CTXT_JOINED) {
1303 spin_unlock(&dlm_domain_lock);
1304
1305 mlog(0, "This ctxt is not joined yet!\n");
1306 wait_event_interruptible(dlm_domain_events,
1307 dlm_wait_on_domain_helper(
1308 domain));
1309 goto retry;
1310 }
1311
1312 __dlm_get(dlm);
1313 dlm->num_joins++;
1314
1315 spin_unlock(&dlm_domain_lock);
1316
1317 ret = 0;
1318 goto leave;
1319 }
1320
1321 /* doesn't exist */
1322 if (!new_ctxt) {
1323 spin_unlock(&dlm_domain_lock);
1324
1325 new_ctxt = dlm_alloc_ctxt(domain, key);
1326 if (new_ctxt)
1327 goto retry;
1328
1329 ret = -ENOMEM;
1330 mlog_errno(ret);
1331 goto leave;
1332 }
1333
1334 /* a little variable switch-a-roo here... */
1335 dlm = new_ctxt;
1336 new_ctxt = NULL;
1337
1338 /* add the new domain */
1339 list_add_tail(&dlm->list, &dlm_domains);
1340 spin_unlock(&dlm_domain_lock);
1341
1342 ret = dlm_join_domain(dlm);
1343 if (ret) {
1344 mlog_errno(ret);
1345 dlm_put(dlm);
1346 goto leave;
1347 }
1348
1349 ret = 0;
1350 leave:
1351 if (new_ctxt)
1352 dlm_free_ctxt_mem(new_ctxt);
1353
1354 if (ret < 0)
1355 dlm = ERR_PTR(ret);
1356
1357 return dlm;
1358 }
1359 EXPORT_SYMBOL_GPL(dlm_register_domain);
1360
1361 static LIST_HEAD(dlm_join_handlers);
1362
1363 static void dlm_unregister_net_handlers(void)
1364 {
1365 o2net_unregister_handler_list(&dlm_join_handlers);
1366 }
1367
1368 static int dlm_register_net_handlers(void)
1369 {
1370 int status = 0;
1371
1372 status = o2net_register_handler(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY,
1373 sizeof(struct dlm_query_join_request),
1374 dlm_query_join_handler,
1375 NULL, &dlm_join_handlers);
1376 if (status)
1377 goto bail;
1378
1379 status = o2net_register_handler(DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
1380 sizeof(struct dlm_assert_joined),
1381 dlm_assert_joined_handler,
1382 NULL, &dlm_join_handlers);
1383 if (status)
1384 goto bail;
1385
1386 status = o2net_register_handler(DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
1387 sizeof(struct dlm_cancel_join),
1388 dlm_cancel_join_handler,
1389 NULL, &dlm_join_handlers);
1390
1391 bail:
1392 if (status < 0)
1393 dlm_unregister_net_handlers();
1394
1395 return status;
1396 }
1397
1398 /* Domain eviction callback handling.
1399 *
1400 * The file system requires notification of node death *before* the
1401 * dlm completes it's recovery work, otherwise it may be able to
1402 * acquire locks on resources requiring recovery. Since the dlm can
1403 * evict a node from it's domain *before* heartbeat fires, a similar
1404 * mechanism is required. */
1405
1406 /* Eviction is not expected to happen often, so a per-domain lock is
1407 * not necessary. Eviction callbacks are allowed to sleep for short
1408 * periods of time. */
1409 static DECLARE_RWSEM(dlm_callback_sem);
1410
1411 void dlm_fire_domain_eviction_callbacks(struct dlm_ctxt *dlm,
1412 int node_num)
1413 {
1414 struct list_head *iter;
1415 struct dlm_eviction_cb *cb;
1416
1417 down_read(&dlm_callback_sem);
1418 list_for_each(iter, &dlm->dlm_eviction_callbacks) {
1419 cb = list_entry(iter, struct dlm_eviction_cb, ec_item);
1420
1421 cb->ec_func(node_num, cb->ec_data);
1422 }
1423 up_read(&dlm_callback_sem);
1424 }
1425
1426 void dlm_setup_eviction_cb(struct dlm_eviction_cb *cb,
1427 dlm_eviction_func *f,
1428 void *data)
1429 {
1430 INIT_LIST_HEAD(&cb->ec_item);
1431 cb->ec_func = f;
1432 cb->ec_data = data;
1433 }
1434 EXPORT_SYMBOL_GPL(dlm_setup_eviction_cb);
1435
1436 void dlm_register_eviction_cb(struct dlm_ctxt *dlm,
1437 struct dlm_eviction_cb *cb)
1438 {
1439 down_write(&dlm_callback_sem);
1440 list_add_tail(&cb->ec_item, &dlm->dlm_eviction_callbacks);
1441 up_write(&dlm_callback_sem);
1442 }
1443 EXPORT_SYMBOL_GPL(dlm_register_eviction_cb);
1444
1445 void dlm_unregister_eviction_cb(struct dlm_eviction_cb *cb)
1446 {
1447 down_write(&dlm_callback_sem);
1448 list_del_init(&cb->ec_item);
1449 up_write(&dlm_callback_sem);
1450 }
1451 EXPORT_SYMBOL_GPL(dlm_unregister_eviction_cb);
1452
1453 static int __init dlm_init(void)
1454 {
1455 int status;
1456
1457 dlm_print_version();
1458
1459 status = dlm_init_mle_cache();
1460 if (status)
1461 return -1;
1462
1463 status = dlm_register_net_handlers();
1464 if (status) {
1465 dlm_destroy_mle_cache();
1466 return -1;
1467 }
1468
1469 return 0;
1470 }
1471
1472 static void __exit dlm_exit (void)
1473 {
1474 dlm_unregister_net_handlers();
1475 dlm_destroy_mle_cache();
1476 }
1477
1478 MODULE_AUTHOR("Oracle");
1479 MODULE_LICENSE("GPL");
1480
1481 module_init(dlm_init);
1482 module_exit(dlm_exit);
Linux kernel - Deliverables
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