Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6
[linux-2.6] / 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 "dlmdomain.h"
45
46 #include "dlmver.h"
47
48 #define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_DOMAIN)
49 #include "cluster/masklog.h"
50
51 static void dlm_free_pagevec(void **vec, int pages)
52 {
53         while (pages--)
54                 free_page((unsigned long)vec[pages]);
55         kfree(vec);
56 }
57
58 static void **dlm_alloc_pagevec(int pages)
59 {
60         void **vec = kmalloc(pages * sizeof(void *), GFP_KERNEL);
61         int i;
62
63         if (!vec)
64                 return NULL;
65
66         for (i = 0; i < pages; i++)
67                 if (!(vec[i] = (void *)__get_free_page(GFP_KERNEL)))
68                         goto out_free;
69
70         mlog(0, "Allocated DLM hash pagevec; %d pages (%lu expected), %lu buckets per page\n",
71              pages, DLM_HASH_PAGES, (unsigned long)DLM_BUCKETS_PER_PAGE);
72         return vec;
73 out_free:
74         dlm_free_pagevec(vec, i);
75         return NULL;
76 }
77
78 /*
79  *
80  * spinlock lock ordering: if multiple locks are needed, obey this ordering:
81  *    dlm_domain_lock
82  *    struct dlm_ctxt->spinlock
83  *    struct dlm_lock_resource->spinlock
84  *    struct dlm_ctxt->master_lock
85  *    struct dlm_ctxt->ast_lock
86  *    dlm_master_list_entry->spinlock
87  *    dlm_lock->spinlock
88  *
89  */
90
91 DEFINE_SPINLOCK(dlm_domain_lock);
92 LIST_HEAD(dlm_domains);
93 static DECLARE_WAIT_QUEUE_HEAD(dlm_domain_events);
94
95 #define DLM_DOMAIN_BACKOFF_MS 200
96
97 static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data);
98 static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data);
99 static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data);
100 static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data);
101
102 static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm);
103
104 void __dlm_unhash_lockres(struct dlm_lock_resource *lockres)
105 {
106         hlist_del_init(&lockres->hash_node);
107         dlm_lockres_put(lockres);
108 }
109
110 void __dlm_insert_lockres(struct dlm_ctxt *dlm,
111                        struct dlm_lock_resource *res)
112 {
113         struct hlist_head *bucket;
114         struct qstr *q;
115
116         assert_spin_locked(&dlm->spinlock);
117
118         q = &res->lockname;
119         bucket = dlm_lockres_hash(dlm, q->hash);
120
121         /* get a reference for our hashtable */
122         dlm_lockres_get(res);
123
124         hlist_add_head(&res->hash_node, bucket);
125 }
126
127 struct dlm_lock_resource * __dlm_lookup_lockres(struct dlm_ctxt *dlm,
128                                                 const char *name,
129                                                 unsigned int len,
130                                                 unsigned int hash)
131 {
132         struct hlist_head *bucket;
133         struct hlist_node *list;
134
135         mlog_entry("%.*s\n", len, name);
136
137         assert_spin_locked(&dlm->spinlock);
138
139         bucket = dlm_lockres_hash(dlm, hash);
140
141         hlist_for_each(list, bucket) {
142                 struct dlm_lock_resource *res = hlist_entry(list,
143                         struct dlm_lock_resource, hash_node);
144                 if (res->lockname.name[0] != name[0])
145                         continue;
146                 if (unlikely(res->lockname.len != len))
147                         continue;
148                 if (memcmp(res->lockname.name + 1, name + 1, len - 1))
149                         continue;
150                 dlm_lockres_get(res);
151                 return res;
152         }
153         return NULL;
154 }
155
156 struct dlm_lock_resource * dlm_lookup_lockres(struct dlm_ctxt *dlm,
157                                     const char *name,
158                                     unsigned int len)
159 {
160         struct dlm_lock_resource *res;
161         unsigned int hash = dlm_lockid_hash(name, len);
162
163         spin_lock(&dlm->spinlock);
164         res = __dlm_lookup_lockres(dlm, name, len, hash);
165         spin_unlock(&dlm->spinlock);
166         return res;
167 }
168
169 static struct dlm_ctxt * __dlm_lookup_domain_full(const char *domain, int len)
170 {
171         struct dlm_ctxt *tmp = NULL;
172         struct list_head *iter;
173
174         assert_spin_locked(&dlm_domain_lock);
175
176         /* tmp->name here is always NULL terminated,
177          * but domain may not be! */
178         list_for_each(iter, &dlm_domains) {
179                 tmp = list_entry (iter, struct dlm_ctxt, list);
180                 if (strlen(tmp->name) == len &&
181                     memcmp(tmp->name, domain, len)==0)
182                         break;
183                 tmp = NULL;
184         }
185
186         return tmp;
187 }
188
189 /* For null terminated domain strings ONLY */
190 static struct dlm_ctxt * __dlm_lookup_domain(const char *domain)
191 {
192         assert_spin_locked(&dlm_domain_lock);
193
194         return __dlm_lookup_domain_full(domain, strlen(domain));
195 }
196
197
198 /* returns true on one of two conditions:
199  * 1) the domain does not exist
200  * 2) the domain exists and it's state is "joined" */
201 static int dlm_wait_on_domain_helper(const char *domain)
202 {
203         int ret = 0;
204         struct dlm_ctxt *tmp = NULL;
205
206         spin_lock(&dlm_domain_lock);
207
208         tmp = __dlm_lookup_domain(domain);
209         if (!tmp)
210                 ret = 1;
211         else if (tmp->dlm_state == DLM_CTXT_JOINED)
212                 ret = 1;
213
214         spin_unlock(&dlm_domain_lock);
215         return ret;
216 }
217
218 static void dlm_free_ctxt_mem(struct dlm_ctxt *dlm)
219 {
220         if (dlm->lockres_hash)
221                 dlm_free_pagevec((void **)dlm->lockres_hash, DLM_HASH_PAGES);
222
223         if (dlm->name)
224                 kfree(dlm->name);
225
226         kfree(dlm);
227 }
228
229 /* A little strange - this function will be called while holding
230  * dlm_domain_lock and is expected to be holding it on the way out. We
231  * will however drop and reacquire it multiple times */
232 static void dlm_ctxt_release(struct kref *kref)
233 {
234         struct dlm_ctxt *dlm;
235
236         dlm = container_of(kref, struct dlm_ctxt, dlm_refs);
237
238         BUG_ON(dlm->num_joins);
239         BUG_ON(dlm->dlm_state == DLM_CTXT_JOINED);
240
241         /* we may still be in the list if we hit an error during join. */
242         list_del_init(&dlm->list);
243
244         spin_unlock(&dlm_domain_lock);
245
246         mlog(0, "freeing memory from domain %s\n", dlm->name);
247
248         wake_up(&dlm_domain_events);
249
250         dlm_free_ctxt_mem(dlm);
251
252         spin_lock(&dlm_domain_lock);
253 }
254
255 void dlm_put(struct dlm_ctxt *dlm)
256 {
257         spin_lock(&dlm_domain_lock);
258         kref_put(&dlm->dlm_refs, dlm_ctxt_release);
259         spin_unlock(&dlm_domain_lock);
260 }
261
262 static void __dlm_get(struct dlm_ctxt *dlm)
263 {
264         kref_get(&dlm->dlm_refs);
265 }
266
267 /* given a questionable reference to a dlm object, gets a reference if
268  * it can find it in the list, otherwise returns NULL in which case
269  * you shouldn't trust your pointer. */
270 struct dlm_ctxt *dlm_grab(struct dlm_ctxt *dlm)
271 {
272         struct list_head *iter;
273         struct dlm_ctxt *target = NULL;
274
275         spin_lock(&dlm_domain_lock);
276
277         list_for_each(iter, &dlm_domains) {
278                 target = list_entry (iter, struct dlm_ctxt, list);
279
280                 if (target == dlm) {
281                         __dlm_get(target);
282                         break;
283                 }
284
285                 target = NULL;
286         }
287
288         spin_unlock(&dlm_domain_lock);
289
290         return target;
291 }
292
293 int dlm_domain_fully_joined(struct dlm_ctxt *dlm)
294 {
295         int ret;
296
297         spin_lock(&dlm_domain_lock);
298         ret = (dlm->dlm_state == DLM_CTXT_JOINED) ||
299                 (dlm->dlm_state == DLM_CTXT_IN_SHUTDOWN);
300         spin_unlock(&dlm_domain_lock);
301
302         return ret;
303 }
304
305 static void dlm_destroy_dlm_worker(struct dlm_ctxt *dlm)
306 {
307         if (dlm->dlm_worker) {
308                 flush_workqueue(dlm->dlm_worker);
309                 destroy_workqueue(dlm->dlm_worker);
310                 dlm->dlm_worker = NULL;
311         }
312 }
313
314 static void dlm_complete_dlm_shutdown(struct dlm_ctxt *dlm)
315 {
316         dlm_unregister_domain_handlers(dlm);
317         dlm_complete_thread(dlm);
318         dlm_complete_recovery_thread(dlm);
319         dlm_destroy_dlm_worker(dlm);
320
321         /* We've left the domain. Now we can take ourselves out of the
322          * list and allow the kref stuff to help us free the
323          * memory. */
324         spin_lock(&dlm_domain_lock);
325         list_del_init(&dlm->list);
326         spin_unlock(&dlm_domain_lock);
327
328         /* Wake up anyone waiting for us to remove this domain */
329         wake_up(&dlm_domain_events);
330 }
331
332 static void dlm_migrate_all_locks(struct dlm_ctxt *dlm)
333 {
334         int i;
335         struct dlm_lock_resource *res;
336
337         mlog(0, "Migrating locks from domain %s\n", dlm->name);
338 restart:
339         spin_lock(&dlm->spinlock);
340         for (i = 0; i < DLM_HASH_BUCKETS; i++) {
341                 while (!hlist_empty(dlm_lockres_hash(dlm, i))) {
342                         res = hlist_entry(dlm_lockres_hash(dlm, i)->first,
343                                           struct dlm_lock_resource, hash_node);
344                         /* need reference when manually grabbing lockres */
345                         dlm_lockres_get(res);
346                         /* this should unhash the lockres
347                          * and exit with dlm->spinlock */
348                         mlog(0, "purging res=%p\n", res);
349                         if (dlm_lockres_is_dirty(dlm, res)) {
350                                 /* HACK!  this should absolutely go.
351                                  * need to figure out why some empty
352                                  * lockreses are still marked dirty */
353                                 mlog(ML_ERROR, "lockres %.*s dirty!\n",
354                                      res->lockname.len, res->lockname.name);
355
356                                 spin_unlock(&dlm->spinlock);
357                                 dlm_kick_thread(dlm, res);
358                                 wait_event(dlm->ast_wq, !dlm_lockres_is_dirty(dlm, res));
359                                 dlm_lockres_put(res);
360                                 goto restart;
361                         }
362                         dlm_purge_lockres(dlm, res);
363                         dlm_lockres_put(res);
364                 }
365         }
366         spin_unlock(&dlm->spinlock);
367
368         mlog(0, "DONE Migrating locks from domain %s\n", dlm->name);
369 }
370
371 static int dlm_no_joining_node(struct dlm_ctxt *dlm)
372 {
373         int ret;
374
375         spin_lock(&dlm->spinlock);
376         ret = dlm->joining_node == DLM_LOCK_RES_OWNER_UNKNOWN;
377         spin_unlock(&dlm->spinlock);
378
379         return ret;
380 }
381
382 static void dlm_mark_domain_leaving(struct dlm_ctxt *dlm)
383 {
384         /* Yikes, a double spinlock! I need domain_lock for the dlm
385          * state and the dlm spinlock for join state... Sorry! */
386 again:
387         spin_lock(&dlm_domain_lock);
388         spin_lock(&dlm->spinlock);
389
390         if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
391                 mlog(0, "Node %d is joining, we wait on it.\n",
392                           dlm->joining_node);
393                 spin_unlock(&dlm->spinlock);
394                 spin_unlock(&dlm_domain_lock);
395
396                 wait_event(dlm->dlm_join_events, dlm_no_joining_node(dlm));
397                 goto again;
398         }
399
400         dlm->dlm_state = DLM_CTXT_LEAVING;
401         spin_unlock(&dlm->spinlock);
402         spin_unlock(&dlm_domain_lock);
403 }
404
405 static void __dlm_print_nodes(struct dlm_ctxt *dlm)
406 {
407         int node = -1;
408
409         assert_spin_locked(&dlm->spinlock);
410
411         printk(KERN_INFO "ocfs2_dlm: Nodes in domain (\"%s\"): ", dlm->name);
412
413         while ((node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES,
414                                      node + 1)) < O2NM_MAX_NODES) {
415                 printk("%d ", node);
416         }
417         printk("\n");
418 }
419
420 static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data)
421 {
422         struct dlm_ctxt *dlm = data;
423         unsigned int node;
424         struct dlm_exit_domain *exit_msg = (struct dlm_exit_domain *) msg->buf;
425
426         mlog_entry("%p %u %p", msg, len, data);
427
428         if (!dlm_grab(dlm))
429                 return 0;
430
431         node = exit_msg->node_idx;
432
433         printk(KERN_INFO "ocfs2_dlm: Node %u leaves domain %s\n", node, dlm->name);
434
435         spin_lock(&dlm->spinlock);
436         clear_bit(node, dlm->domain_map);
437         __dlm_print_nodes(dlm);
438
439         /* notify anything attached to the heartbeat events */
440         dlm_hb_event_notify_attached(dlm, node, 0);
441
442         spin_unlock(&dlm->spinlock);
443
444         dlm_put(dlm);
445
446         return 0;
447 }
448
449 static int dlm_send_one_domain_exit(struct dlm_ctxt *dlm,
450                                     unsigned int node)
451 {
452         int status;
453         struct dlm_exit_domain leave_msg;
454
455         mlog(0, "Asking node %u if we can leave the domain %s me = %u\n",
456                   node, dlm->name, dlm->node_num);
457
458         memset(&leave_msg, 0, sizeof(leave_msg));
459         leave_msg.node_idx = dlm->node_num;
460
461         status = o2net_send_message(DLM_EXIT_DOMAIN_MSG, dlm->key,
462                                     &leave_msg, sizeof(leave_msg), node,
463                                     NULL);
464
465         mlog(0, "status return %d from o2net_send_message\n", status);
466
467         return status;
468 }
469
470
471 static void dlm_leave_domain(struct dlm_ctxt *dlm)
472 {
473         int node, clear_node, status;
474
475         /* At this point we've migrated away all our locks and won't
476          * accept mastership of new ones. The dlm is responsible for
477          * almost nothing now. We make sure not to confuse any joining
478          * nodes and then commence shutdown procedure. */
479
480         spin_lock(&dlm->spinlock);
481         /* Clear ourselves from the domain map */
482         clear_bit(dlm->node_num, dlm->domain_map);
483         while ((node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES,
484                                      0)) < O2NM_MAX_NODES) {
485                 /* Drop the dlm spinlock. This is safe wrt the domain_map.
486                  * -nodes cannot be added now as the
487                  *   query_join_handlers knows to respond with OK_NO_MAP
488                  * -we catch the right network errors if a node is
489                  *   removed from the map while we're sending him the
490                  *   exit message. */
491                 spin_unlock(&dlm->spinlock);
492
493                 clear_node = 1;
494
495                 status = dlm_send_one_domain_exit(dlm, node);
496                 if (status < 0 &&
497                     status != -ENOPROTOOPT &&
498                     status != -ENOTCONN) {
499                         mlog(ML_NOTICE, "Error %d sending domain exit message "
500                              "to node %d\n", status, node);
501
502                         /* Not sure what to do here but lets sleep for
503                          * a bit in case this was a transient
504                          * error... */
505                         msleep(DLM_DOMAIN_BACKOFF_MS);
506                         clear_node = 0;
507                 }
508
509                 spin_lock(&dlm->spinlock);
510                 /* If we're not clearing the node bit then we intend
511                  * to loop back around to try again. */
512                 if (clear_node)
513                         clear_bit(node, dlm->domain_map);
514         }
515         spin_unlock(&dlm->spinlock);
516 }
517
518 int dlm_joined(struct dlm_ctxt *dlm)
519 {
520         int ret = 0;
521
522         spin_lock(&dlm_domain_lock);
523
524         if (dlm->dlm_state == DLM_CTXT_JOINED)
525                 ret = 1;
526
527         spin_unlock(&dlm_domain_lock);
528
529         return ret;
530 }
531
532 int dlm_shutting_down(struct dlm_ctxt *dlm)
533 {
534         int ret = 0;
535
536         spin_lock(&dlm_domain_lock);
537
538         if (dlm->dlm_state == DLM_CTXT_IN_SHUTDOWN)
539                 ret = 1;
540
541         spin_unlock(&dlm_domain_lock);
542
543         return ret;
544 }
545
546 void dlm_unregister_domain(struct dlm_ctxt *dlm)
547 {
548         int leave = 0;
549
550         spin_lock(&dlm_domain_lock);
551         BUG_ON(dlm->dlm_state != DLM_CTXT_JOINED);
552         BUG_ON(!dlm->num_joins);
553
554         dlm->num_joins--;
555         if (!dlm->num_joins) {
556                 /* We mark it "in shutdown" now so new register
557                  * requests wait until we've completely left the
558                  * domain. Don't use DLM_CTXT_LEAVING yet as we still
559                  * want new domain joins to communicate with us at
560                  * least until we've completed migration of our
561                  * resources. */
562                 dlm->dlm_state = DLM_CTXT_IN_SHUTDOWN;
563                 leave = 1;
564         }
565         spin_unlock(&dlm_domain_lock);
566
567         if (leave) {
568                 mlog(0, "shutting down domain %s\n", dlm->name);
569
570                 /* We changed dlm state, notify the thread */
571                 dlm_kick_thread(dlm, NULL);
572
573                 dlm_migrate_all_locks(dlm);
574                 dlm_mark_domain_leaving(dlm);
575                 dlm_leave_domain(dlm);
576                 dlm_complete_dlm_shutdown(dlm);
577         }
578         dlm_put(dlm);
579 }
580 EXPORT_SYMBOL_GPL(dlm_unregister_domain);
581
582 static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data)
583 {
584         struct dlm_query_join_request *query;
585         enum dlm_query_join_response response;
586         struct dlm_ctxt *dlm = NULL;
587
588         query = (struct dlm_query_join_request *) msg->buf;
589
590         mlog(0, "node %u wants to join domain %s\n", query->node_idx,
591                   query->domain);
592
593         /*
594          * If heartbeat doesn't consider the node live, tell it
595          * to back off and try again.  This gives heartbeat a chance
596          * to catch up.
597          */
598         if (!o2hb_check_node_heartbeating(query->node_idx)) {
599                 mlog(0, "node %u is not in our live map yet\n",
600                      query->node_idx);
601
602                 response = JOIN_DISALLOW;
603                 goto respond;
604         }
605
606         response = JOIN_OK_NO_MAP;
607
608         spin_lock(&dlm_domain_lock);
609         dlm = __dlm_lookup_domain_full(query->domain, query->name_len);
610         /* Once the dlm ctxt is marked as leaving then we don't want
611          * to be put in someone's domain map. 
612          * Also, explicitly disallow joining at certain troublesome
613          * times (ie. during recovery). */
614         if (dlm && dlm->dlm_state != DLM_CTXT_LEAVING) {
615                 int bit = query->node_idx;
616                 spin_lock(&dlm->spinlock);
617
618                 if (dlm->dlm_state == DLM_CTXT_NEW &&
619                     dlm->joining_node == DLM_LOCK_RES_OWNER_UNKNOWN) {
620                         /*If this is a brand new context and we
621                          * haven't started our join process yet, then
622                          * the other node won the race. */
623                         response = JOIN_OK_NO_MAP;
624                 } else if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
625                         /* Disallow parallel joins. */
626                         response = JOIN_DISALLOW;
627                 } else if (dlm->reco.state & DLM_RECO_STATE_ACTIVE) {
628                         mlog(ML_NOTICE, "node %u trying to join, but recovery "
629                              "is ongoing.\n", bit);
630                         response = JOIN_DISALLOW;
631                 } else if (test_bit(bit, dlm->recovery_map)) {
632                         mlog(ML_NOTICE, "node %u trying to join, but it "
633                              "still needs recovery.\n", bit);
634                         response = JOIN_DISALLOW;
635                 } else if (test_bit(bit, dlm->domain_map)) {
636                         mlog(ML_NOTICE, "node %u trying to join, but it "
637                              "is still in the domain! needs recovery?\n",
638                              bit);
639                         response = JOIN_DISALLOW;
640                 } else {
641                         /* Alright we're fully a part of this domain
642                          * so we keep some state as to who's joining
643                          * and indicate to him that needs to be fixed
644                          * up. */
645                         response = JOIN_OK;
646                         __dlm_set_joining_node(dlm, query->node_idx);
647                 }
648
649                 spin_unlock(&dlm->spinlock);
650         }
651         spin_unlock(&dlm_domain_lock);
652
653 respond:
654         mlog(0, "We respond with %u\n", response);
655
656         return response;
657 }
658
659 static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data)
660 {
661         struct dlm_assert_joined *assert;
662         struct dlm_ctxt *dlm = NULL;
663
664         assert = (struct dlm_assert_joined *) msg->buf;
665
666         mlog(0, "node %u asserts join on domain %s\n", assert->node_idx,
667                   assert->domain);
668
669         spin_lock(&dlm_domain_lock);
670         dlm = __dlm_lookup_domain_full(assert->domain, assert->name_len);
671         /* XXX should we consider no dlm ctxt an error? */
672         if (dlm) {
673                 spin_lock(&dlm->spinlock);
674
675                 /* Alright, this node has officially joined our
676                  * domain. Set him in the map and clean up our
677                  * leftover join state. */
678                 BUG_ON(dlm->joining_node != assert->node_idx);
679                 set_bit(assert->node_idx, dlm->domain_map);
680                 __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
681
682                 printk(KERN_INFO "ocfs2_dlm: Node %u joins domain %s\n",
683                        assert->node_idx, dlm->name);
684                 __dlm_print_nodes(dlm);
685
686                 /* notify anything attached to the heartbeat events */
687                 dlm_hb_event_notify_attached(dlm, assert->node_idx, 1);
688
689                 spin_unlock(&dlm->spinlock);
690         }
691         spin_unlock(&dlm_domain_lock);
692
693         return 0;
694 }
695
696 static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data)
697 {
698         struct dlm_cancel_join *cancel;
699         struct dlm_ctxt *dlm = NULL;
700
701         cancel = (struct dlm_cancel_join *) msg->buf;
702
703         mlog(0, "node %u cancels join on domain %s\n", cancel->node_idx,
704                   cancel->domain);
705
706         spin_lock(&dlm_domain_lock);
707         dlm = __dlm_lookup_domain_full(cancel->domain, cancel->name_len);
708
709         if (dlm) {
710                 spin_lock(&dlm->spinlock);
711
712                 /* Yikes, this guy wants to cancel his join. No
713                  * problem, we simply cleanup our join state. */
714                 BUG_ON(dlm->joining_node != cancel->node_idx);
715                 __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
716
717                 spin_unlock(&dlm->spinlock);
718         }
719         spin_unlock(&dlm_domain_lock);
720
721         return 0;
722 }
723
724 static int dlm_send_one_join_cancel(struct dlm_ctxt *dlm,
725                                     unsigned int node)
726 {
727         int status;
728         struct dlm_cancel_join cancel_msg;
729
730         memset(&cancel_msg, 0, sizeof(cancel_msg));
731         cancel_msg.node_idx = dlm->node_num;
732         cancel_msg.name_len = strlen(dlm->name);
733         memcpy(cancel_msg.domain, dlm->name, cancel_msg.name_len);
734
735         status = o2net_send_message(DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
736                                     &cancel_msg, sizeof(cancel_msg), node,
737                                     NULL);
738         if (status < 0) {
739                 mlog_errno(status);
740                 goto bail;
741         }
742
743 bail:
744         return status;
745 }
746
747 /* map_size should be in bytes. */
748 static int dlm_send_join_cancels(struct dlm_ctxt *dlm,
749                                  unsigned long *node_map,
750                                  unsigned int map_size)
751 {
752         int status, tmpstat;
753         unsigned int node;
754
755         if (map_size != (BITS_TO_LONGS(O2NM_MAX_NODES) *
756                          sizeof(unsigned long))) {
757                 mlog(ML_ERROR,
758                      "map_size %u != BITS_TO_LONGS(O2NM_MAX_NODES) %u\n",
759                      map_size, BITS_TO_LONGS(O2NM_MAX_NODES));
760                 return -EINVAL;
761         }
762
763         status = 0;
764         node = -1;
765         while ((node = find_next_bit(node_map, O2NM_MAX_NODES,
766                                      node + 1)) < O2NM_MAX_NODES) {
767                 if (node == dlm->node_num)
768                         continue;
769
770                 tmpstat = dlm_send_one_join_cancel(dlm, node);
771                 if (tmpstat) {
772                         mlog(ML_ERROR, "Error return %d cancelling join on "
773                              "node %d\n", tmpstat, node);
774                         if (!status)
775                                 status = tmpstat;
776                 }
777         }
778
779         if (status)
780                 mlog_errno(status);
781         return status;
782 }
783
784 static int dlm_request_join(struct dlm_ctxt *dlm,
785                             int node,
786                             enum dlm_query_join_response *response)
787 {
788         int status, retval;
789         struct dlm_query_join_request join_msg;
790
791         mlog(0, "querying node %d\n", node);
792
793         memset(&join_msg, 0, sizeof(join_msg));
794         join_msg.node_idx = dlm->node_num;
795         join_msg.name_len = strlen(dlm->name);
796         memcpy(join_msg.domain, dlm->name, join_msg.name_len);
797
798         status = o2net_send_message(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY, &join_msg,
799                                     sizeof(join_msg), node, &retval);
800         if (status < 0 && status != -ENOPROTOOPT) {
801                 mlog_errno(status);
802                 goto bail;
803         }
804
805         /* -ENOPROTOOPT from the net code means the other side isn't
806             listening for our message type -- that's fine, it means
807             his dlm isn't up, so we can consider him a 'yes' but not
808             joined into the domain.  */
809         if (status == -ENOPROTOOPT) {
810                 status = 0;
811                 *response = JOIN_OK_NO_MAP;
812         } else if (retval == JOIN_DISALLOW ||
813                    retval == JOIN_OK ||
814                    retval == JOIN_OK_NO_MAP) {
815                 *response = retval;
816         } else {
817                 status = -EINVAL;
818                 mlog(ML_ERROR, "invalid response %d from node %u\n", retval,
819                      node);
820         }
821
822         mlog(0, "status %d, node %d response is %d\n", status, node,
823                   *response);
824
825 bail:
826         return status;
827 }
828
829 static int dlm_send_one_join_assert(struct dlm_ctxt *dlm,
830                                     unsigned int node)
831 {
832         int status;
833         struct dlm_assert_joined assert_msg;
834
835         mlog(0, "Sending join assert to node %u\n", node);
836
837         memset(&assert_msg, 0, sizeof(assert_msg));
838         assert_msg.node_idx = dlm->node_num;
839         assert_msg.name_len = strlen(dlm->name);
840         memcpy(assert_msg.domain, dlm->name, assert_msg.name_len);
841
842         status = o2net_send_message(DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
843                                     &assert_msg, sizeof(assert_msg), node,
844                                     NULL);
845         if (status < 0)
846                 mlog_errno(status);
847
848         return status;
849 }
850
851 static void dlm_send_join_asserts(struct dlm_ctxt *dlm,
852                                   unsigned long *node_map)
853 {
854         int status, node, live;
855
856         status = 0;
857         node = -1;
858         while ((node = find_next_bit(node_map, O2NM_MAX_NODES,
859                                      node + 1)) < O2NM_MAX_NODES) {
860                 if (node == dlm->node_num)
861                         continue;
862
863                 do {
864                         /* It is very important that this message be
865                          * received so we spin until either the node
866                          * has died or it gets the message. */
867                         status = dlm_send_one_join_assert(dlm, node);
868
869                         spin_lock(&dlm->spinlock);
870                         live = test_bit(node, dlm->live_nodes_map);
871                         spin_unlock(&dlm->spinlock);
872
873                         if (status) {
874                                 mlog(ML_ERROR, "Error return %d asserting "
875                                      "join on node %d\n", status, node);
876
877                                 /* give us some time between errors... */
878                                 if (live)
879                                         msleep(DLM_DOMAIN_BACKOFF_MS);
880                         }
881                 } while (status && live);
882         }
883 }
884
885 struct domain_join_ctxt {
886         unsigned long live_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
887         unsigned long yes_resp_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
888 };
889
890 static int dlm_should_restart_join(struct dlm_ctxt *dlm,
891                                    struct domain_join_ctxt *ctxt,
892                                    enum dlm_query_join_response response)
893 {
894         int ret;
895
896         if (response == JOIN_DISALLOW) {
897                 mlog(0, "Latest response of disallow -- should restart\n");
898                 return 1;
899         }
900
901         spin_lock(&dlm->spinlock);
902         /* For now, we restart the process if the node maps have
903          * changed at all */
904         ret = memcmp(ctxt->live_map, dlm->live_nodes_map,
905                      sizeof(dlm->live_nodes_map));
906         spin_unlock(&dlm->spinlock);
907
908         if (ret)
909                 mlog(0, "Node maps changed -- should restart\n");
910
911         return ret;
912 }
913
914 static int dlm_try_to_join_domain(struct dlm_ctxt *dlm)
915 {
916         int status = 0, tmpstat, node;
917         struct domain_join_ctxt *ctxt;
918         enum dlm_query_join_response response;
919
920         mlog_entry("%p", dlm);
921
922         ctxt = kcalloc(1, sizeof(*ctxt), GFP_KERNEL);
923         if (!ctxt) {
924                 status = -ENOMEM;
925                 mlog_errno(status);
926                 goto bail;
927         }
928
929         /* group sem locking should work for us here -- we're already
930          * registered for heartbeat events so filling this should be
931          * atomic wrt getting those handlers called. */
932         o2hb_fill_node_map(dlm->live_nodes_map, sizeof(dlm->live_nodes_map));
933
934         spin_lock(&dlm->spinlock);
935         memcpy(ctxt->live_map, dlm->live_nodes_map, sizeof(ctxt->live_map));
936
937         __dlm_set_joining_node(dlm, dlm->node_num);
938
939         spin_unlock(&dlm->spinlock);
940
941         node = -1;
942         while ((node = find_next_bit(ctxt->live_map, O2NM_MAX_NODES,
943                                      node + 1)) < O2NM_MAX_NODES) {
944                 if (node == dlm->node_num)
945                         continue;
946
947                 status = dlm_request_join(dlm, node, &response);
948                 if (status < 0) {
949                         mlog_errno(status);
950                         goto bail;
951                 }
952
953                 /* Ok, either we got a response or the node doesn't have a
954                  * dlm up. */
955                 if (response == JOIN_OK)
956                         set_bit(node, ctxt->yes_resp_map);
957
958                 if (dlm_should_restart_join(dlm, ctxt, response)) {
959                         status = -EAGAIN;
960                         goto bail;
961                 }
962         }
963
964         mlog(0, "Yay, done querying nodes!\n");
965
966         /* Yay, everyone agree's we can join the domain. My domain is
967          * comprised of all nodes who were put in the
968          * yes_resp_map. Copy that into our domain map and send a join
969          * assert message to clean up everyone elses state. */
970         spin_lock(&dlm->spinlock);
971         memcpy(dlm->domain_map, ctxt->yes_resp_map,
972                sizeof(ctxt->yes_resp_map));
973         set_bit(dlm->node_num, dlm->domain_map);
974         spin_unlock(&dlm->spinlock);
975
976         dlm_send_join_asserts(dlm, ctxt->yes_resp_map);
977
978         /* Joined state *must* be set before the joining node
979          * information, otherwise the query_join handler may read no
980          * current joiner but a state of NEW and tell joining nodes
981          * we're not in the domain. */
982         spin_lock(&dlm_domain_lock);
983         dlm->dlm_state = DLM_CTXT_JOINED;
984         dlm->num_joins++;
985         spin_unlock(&dlm_domain_lock);
986
987 bail:
988         spin_lock(&dlm->spinlock);
989         __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
990         if (!status)
991                 __dlm_print_nodes(dlm);
992         spin_unlock(&dlm->spinlock);
993
994         if (ctxt) {
995                 /* Do we need to send a cancel message to any nodes? */
996                 if (status < 0) {
997                         tmpstat = dlm_send_join_cancels(dlm,
998                                                         ctxt->yes_resp_map,
999                                                         sizeof(ctxt->yes_resp_map));
1000                         if (tmpstat < 0)
1001                                 mlog_errno(tmpstat);
1002                 }
1003                 kfree(ctxt);
1004         }
1005
1006         mlog(0, "returning %d\n", status);
1007         return status;
1008 }
1009
1010 static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm)
1011 {
1012         o2hb_unregister_callback(&dlm->dlm_hb_up);
1013         o2hb_unregister_callback(&dlm->dlm_hb_down);
1014         o2net_unregister_handler_list(&dlm->dlm_domain_handlers);
1015 }
1016
1017 static int dlm_register_domain_handlers(struct dlm_ctxt *dlm)
1018 {
1019         int status;
1020
1021         mlog(0, "registering handlers.\n");
1022
1023         o2hb_setup_callback(&dlm->dlm_hb_down, O2HB_NODE_DOWN_CB,
1024                             dlm_hb_node_down_cb, dlm, DLM_HB_NODE_DOWN_PRI);
1025         status = o2hb_register_callback(&dlm->dlm_hb_down);
1026         if (status)
1027                 goto bail;
1028
1029         o2hb_setup_callback(&dlm->dlm_hb_up, O2HB_NODE_UP_CB,
1030                             dlm_hb_node_up_cb, dlm, DLM_HB_NODE_UP_PRI);
1031         status = o2hb_register_callback(&dlm->dlm_hb_up);
1032         if (status)
1033                 goto bail;
1034
1035         status = o2net_register_handler(DLM_MASTER_REQUEST_MSG, dlm->key,
1036                                         sizeof(struct dlm_master_request),
1037                                         dlm_master_request_handler,
1038                                         dlm, &dlm->dlm_domain_handlers);
1039         if (status)
1040                 goto bail;
1041
1042         status = o2net_register_handler(DLM_ASSERT_MASTER_MSG, dlm->key,
1043                                         sizeof(struct dlm_assert_master),
1044                                         dlm_assert_master_handler,
1045                                         dlm, &dlm->dlm_domain_handlers);
1046         if (status)
1047                 goto bail;
1048
1049         status = o2net_register_handler(DLM_CREATE_LOCK_MSG, dlm->key,
1050                                         sizeof(struct dlm_create_lock),
1051                                         dlm_create_lock_handler,
1052                                         dlm, &dlm->dlm_domain_handlers);
1053         if (status)
1054                 goto bail;
1055
1056         status = o2net_register_handler(DLM_CONVERT_LOCK_MSG, dlm->key,
1057                                         DLM_CONVERT_LOCK_MAX_LEN,
1058                                         dlm_convert_lock_handler,
1059                                         dlm, &dlm->dlm_domain_handlers);
1060         if (status)
1061                 goto bail;
1062
1063         status = o2net_register_handler(DLM_UNLOCK_LOCK_MSG, dlm->key,
1064                                         DLM_UNLOCK_LOCK_MAX_LEN,
1065                                         dlm_unlock_lock_handler,
1066                                         dlm, &dlm->dlm_domain_handlers);
1067         if (status)
1068                 goto bail;
1069
1070         status = o2net_register_handler(DLM_PROXY_AST_MSG, dlm->key,
1071                                         DLM_PROXY_AST_MAX_LEN,
1072                                         dlm_proxy_ast_handler,
1073                                         dlm, &dlm->dlm_domain_handlers);
1074         if (status)
1075                 goto bail;
1076
1077         status = o2net_register_handler(DLM_EXIT_DOMAIN_MSG, dlm->key,
1078                                         sizeof(struct dlm_exit_domain),
1079                                         dlm_exit_domain_handler,
1080                                         dlm, &dlm->dlm_domain_handlers);
1081         if (status)
1082                 goto bail;
1083
1084         status = o2net_register_handler(DLM_MIGRATE_REQUEST_MSG, dlm->key,
1085                                         sizeof(struct dlm_migrate_request),
1086                                         dlm_migrate_request_handler,
1087                                         dlm, &dlm->dlm_domain_handlers);
1088         if (status)
1089                 goto bail;
1090
1091         status = o2net_register_handler(DLM_MIG_LOCKRES_MSG, dlm->key,
1092                                         DLM_MIG_LOCKRES_MAX_LEN,
1093                                         dlm_mig_lockres_handler,
1094                                         dlm, &dlm->dlm_domain_handlers);
1095         if (status)
1096                 goto bail;
1097
1098         status = o2net_register_handler(DLM_MASTER_REQUERY_MSG, dlm->key,
1099                                         sizeof(struct dlm_master_requery),
1100                                         dlm_master_requery_handler,
1101                                         dlm, &dlm->dlm_domain_handlers);
1102         if (status)
1103                 goto bail;
1104
1105         status = o2net_register_handler(DLM_LOCK_REQUEST_MSG, dlm->key,
1106                                         sizeof(struct dlm_lock_request),
1107                                         dlm_request_all_locks_handler,
1108                                         dlm, &dlm->dlm_domain_handlers);
1109         if (status)
1110                 goto bail;
1111
1112         status = o2net_register_handler(DLM_RECO_DATA_DONE_MSG, dlm->key,
1113                                         sizeof(struct dlm_reco_data_done),
1114                                         dlm_reco_data_done_handler,
1115                                         dlm, &dlm->dlm_domain_handlers);
1116         if (status)
1117                 goto bail;
1118
1119         status = o2net_register_handler(DLM_BEGIN_RECO_MSG, dlm->key,
1120                                         sizeof(struct dlm_begin_reco),
1121                                         dlm_begin_reco_handler,
1122                                         dlm, &dlm->dlm_domain_handlers);
1123         if (status)
1124                 goto bail;
1125
1126         status = o2net_register_handler(DLM_FINALIZE_RECO_MSG, dlm->key,
1127                                         sizeof(struct dlm_finalize_reco),
1128                                         dlm_finalize_reco_handler,
1129                                         dlm, &dlm->dlm_domain_handlers);
1130         if (status)
1131                 goto bail;
1132
1133 bail:
1134         if (status)
1135                 dlm_unregister_domain_handlers(dlm);
1136
1137         return status;
1138 }
1139
1140 static int dlm_join_domain(struct dlm_ctxt *dlm)
1141 {
1142         int status;
1143
1144         BUG_ON(!dlm);
1145
1146         mlog(0, "Join domain %s\n", dlm->name);
1147
1148         status = dlm_register_domain_handlers(dlm);
1149         if (status) {
1150                 mlog_errno(status);
1151                 goto bail;
1152         }
1153
1154         status = dlm_launch_thread(dlm);
1155         if (status < 0) {
1156                 mlog_errno(status);
1157                 goto bail;
1158         }
1159
1160         status = dlm_launch_recovery_thread(dlm);
1161         if (status < 0) {
1162                 mlog_errno(status);
1163                 goto bail;
1164         }
1165
1166         dlm->dlm_worker = create_singlethread_workqueue("dlm_wq");
1167         if (!dlm->dlm_worker) {
1168                 status = -ENOMEM;
1169                 mlog_errno(status);
1170                 goto bail;
1171         }
1172
1173         do {
1174                 unsigned int backoff;
1175                 status = dlm_try_to_join_domain(dlm);
1176
1177                 /* If we're racing another node to the join, then we
1178                  * need to back off temporarily and let them
1179                  * complete. */
1180                 if (status == -EAGAIN) {
1181                         if (signal_pending(current)) {
1182                                 status = -ERESTARTSYS;
1183                                 goto bail;
1184                         }
1185
1186                         /*
1187                          * <chip> After you!
1188                          * <dale> No, after you!
1189                          * <chip> I insist!
1190                          * <dale> But you first!
1191                          * ...
1192                          */
1193                         backoff = (unsigned int)(jiffies & 0x3);
1194                         backoff *= DLM_DOMAIN_BACKOFF_MS;
1195                         mlog(0, "backoff %d\n", backoff);
1196                         msleep(backoff);
1197                 }
1198         } while (status == -EAGAIN);
1199
1200         if (status < 0) {
1201                 mlog_errno(status);
1202                 goto bail;
1203         }
1204
1205         status = 0;
1206 bail:
1207         wake_up(&dlm_domain_events);
1208
1209         if (status) {
1210                 dlm_unregister_domain_handlers(dlm);
1211                 dlm_complete_thread(dlm);
1212                 dlm_complete_recovery_thread(dlm);
1213                 dlm_destroy_dlm_worker(dlm);
1214         }
1215
1216         return status;
1217 }
1218
1219 static struct dlm_ctxt *dlm_alloc_ctxt(const char *domain,
1220                                 u32 key)
1221 {
1222         int i;
1223         struct dlm_ctxt *dlm = NULL;
1224
1225         dlm = kcalloc(1, sizeof(*dlm), GFP_KERNEL);
1226         if (!dlm) {
1227                 mlog_errno(-ENOMEM);
1228                 goto leave;
1229         }
1230
1231         dlm->name = kmalloc(strlen(domain) + 1, GFP_KERNEL);
1232         if (dlm->name == NULL) {
1233                 mlog_errno(-ENOMEM);
1234                 kfree(dlm);
1235                 dlm = NULL;
1236                 goto leave;
1237         }
1238
1239         dlm->lockres_hash = (struct hlist_head **)dlm_alloc_pagevec(DLM_HASH_PAGES);
1240         if (!dlm->lockres_hash) {
1241                 mlog_errno(-ENOMEM);
1242                 kfree(dlm->name);
1243                 kfree(dlm);
1244                 dlm = NULL;
1245                 goto leave;
1246         }
1247
1248         for (i = 0; i < DLM_HASH_BUCKETS; i++)
1249                 INIT_HLIST_HEAD(dlm_lockres_hash(dlm, i));
1250
1251         strcpy(dlm->name, domain);
1252         dlm->key = key;
1253         dlm->node_num = o2nm_this_node();
1254
1255         spin_lock_init(&dlm->spinlock);
1256         spin_lock_init(&dlm->master_lock);
1257         spin_lock_init(&dlm->ast_lock);
1258         INIT_LIST_HEAD(&dlm->list);
1259         INIT_LIST_HEAD(&dlm->dirty_list);
1260         INIT_LIST_HEAD(&dlm->reco.resources);
1261         INIT_LIST_HEAD(&dlm->reco.received);
1262         INIT_LIST_HEAD(&dlm->reco.node_data);
1263         INIT_LIST_HEAD(&dlm->purge_list);
1264         INIT_LIST_HEAD(&dlm->dlm_domain_handlers);
1265         dlm->reco.state = 0;
1266
1267         INIT_LIST_HEAD(&dlm->pending_asts);
1268         INIT_LIST_HEAD(&dlm->pending_basts);
1269
1270         mlog(0, "dlm->recovery_map=%p, &(dlm->recovery_map[0])=%p\n",
1271                   dlm->recovery_map, &(dlm->recovery_map[0]));
1272
1273         memset(dlm->recovery_map, 0, sizeof(dlm->recovery_map));
1274         memset(dlm->live_nodes_map, 0, sizeof(dlm->live_nodes_map));
1275         memset(dlm->domain_map, 0, sizeof(dlm->domain_map));
1276
1277         dlm->dlm_thread_task = NULL;
1278         dlm->dlm_reco_thread_task = NULL;
1279         dlm->dlm_worker = NULL;
1280         init_waitqueue_head(&dlm->dlm_thread_wq);
1281         init_waitqueue_head(&dlm->dlm_reco_thread_wq);
1282         init_waitqueue_head(&dlm->reco.event);
1283         init_waitqueue_head(&dlm->ast_wq);
1284         init_waitqueue_head(&dlm->migration_wq);
1285         INIT_LIST_HEAD(&dlm->master_list);
1286         INIT_LIST_HEAD(&dlm->mle_hb_events);
1287
1288         dlm->joining_node = DLM_LOCK_RES_OWNER_UNKNOWN;
1289         init_waitqueue_head(&dlm->dlm_join_events);
1290
1291         dlm->reco.new_master = O2NM_INVALID_NODE_NUM;
1292         dlm->reco.dead_node = O2NM_INVALID_NODE_NUM;
1293         atomic_set(&dlm->local_resources, 0);
1294         atomic_set(&dlm->remote_resources, 0);
1295         atomic_set(&dlm->unknown_resources, 0);
1296
1297         spin_lock_init(&dlm->work_lock);
1298         INIT_LIST_HEAD(&dlm->work_list);
1299         INIT_WORK(&dlm->dispatched_work, dlm_dispatch_work, dlm);
1300
1301         kref_init(&dlm->dlm_refs);
1302         dlm->dlm_state = DLM_CTXT_NEW;
1303
1304         INIT_LIST_HEAD(&dlm->dlm_eviction_callbacks);
1305
1306         mlog(0, "context init: refcount %u\n",
1307                   atomic_read(&dlm->dlm_refs.refcount));
1308
1309 leave:
1310         return dlm;
1311 }
1312
1313 /*
1314  * dlm_register_domain: one-time setup per "domain"
1315  */
1316 struct dlm_ctxt * dlm_register_domain(const char *domain,
1317                                u32 key)
1318 {
1319         int ret;
1320         struct dlm_ctxt *dlm = NULL;
1321         struct dlm_ctxt *new_ctxt = NULL;
1322
1323         if (strlen(domain) > O2NM_MAX_NAME_LEN) {
1324                 ret = -ENAMETOOLONG;
1325                 mlog(ML_ERROR, "domain name length too long\n");
1326                 goto leave;
1327         }
1328
1329         if (!o2hb_check_local_node_heartbeating()) {
1330                 mlog(ML_ERROR, "the local node has not been configured, or is "
1331                      "not heartbeating\n");
1332                 ret = -EPROTO;
1333                 goto leave;
1334         }
1335
1336         mlog(0, "register called for domain \"%s\"\n", domain);
1337
1338 retry:
1339         dlm = NULL;
1340         if (signal_pending(current)) {
1341                 ret = -ERESTARTSYS;
1342                 mlog_errno(ret);
1343                 goto leave;
1344         }
1345
1346         spin_lock(&dlm_domain_lock);
1347
1348         dlm = __dlm_lookup_domain(domain);
1349         if (dlm) {
1350                 if (dlm->dlm_state != DLM_CTXT_JOINED) {
1351                         spin_unlock(&dlm_domain_lock);
1352
1353                         mlog(0, "This ctxt is not joined yet!\n");
1354                         wait_event_interruptible(dlm_domain_events,
1355                                                  dlm_wait_on_domain_helper(
1356                                                          domain));
1357                         goto retry;
1358                 }
1359
1360                 __dlm_get(dlm);
1361                 dlm->num_joins++;
1362
1363                 spin_unlock(&dlm_domain_lock);
1364
1365                 ret = 0;
1366                 goto leave;
1367         }
1368
1369         /* doesn't exist */
1370         if (!new_ctxt) {
1371                 spin_unlock(&dlm_domain_lock);
1372
1373                 new_ctxt = dlm_alloc_ctxt(domain, key);
1374                 if (new_ctxt)
1375                         goto retry;
1376
1377                 ret = -ENOMEM;
1378                 mlog_errno(ret);
1379                 goto leave;
1380         }
1381
1382         /* a little variable switch-a-roo here... */
1383         dlm = new_ctxt;
1384         new_ctxt = NULL;
1385
1386         /* add the new domain */
1387         list_add_tail(&dlm->list, &dlm_domains);
1388         spin_unlock(&dlm_domain_lock);
1389
1390         ret = dlm_join_domain(dlm);
1391         if (ret) {
1392                 mlog_errno(ret);
1393                 dlm_put(dlm);
1394                 goto leave;
1395         }
1396
1397         ret = 0;
1398 leave:
1399         if (new_ctxt)
1400                 dlm_free_ctxt_mem(new_ctxt);
1401
1402         if (ret < 0)
1403                 dlm = ERR_PTR(ret);
1404
1405         return dlm;
1406 }
1407 EXPORT_SYMBOL_GPL(dlm_register_domain);
1408
1409 static LIST_HEAD(dlm_join_handlers);
1410
1411 static void dlm_unregister_net_handlers(void)
1412 {
1413         o2net_unregister_handler_list(&dlm_join_handlers);
1414 }
1415
1416 static int dlm_register_net_handlers(void)
1417 {
1418         int status = 0;
1419
1420         status = o2net_register_handler(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY,
1421                                         sizeof(struct dlm_query_join_request),
1422                                         dlm_query_join_handler,
1423                                         NULL, &dlm_join_handlers);
1424         if (status)
1425                 goto bail;
1426
1427         status = o2net_register_handler(DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
1428                                         sizeof(struct dlm_assert_joined),
1429                                         dlm_assert_joined_handler,
1430                                         NULL, &dlm_join_handlers);
1431         if (status)
1432                 goto bail;
1433
1434         status = o2net_register_handler(DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
1435                                         sizeof(struct dlm_cancel_join),
1436                                         dlm_cancel_join_handler,
1437                                         NULL, &dlm_join_handlers);
1438
1439 bail:
1440         if (status < 0)
1441                 dlm_unregister_net_handlers();
1442
1443         return status;
1444 }
1445
1446 /* Domain eviction callback handling.
1447  *
1448  * The file system requires notification of node death *before* the
1449  * dlm completes it's recovery work, otherwise it may be able to
1450  * acquire locks on resources requiring recovery. Since the dlm can
1451  * evict a node from it's domain *before* heartbeat fires, a similar
1452  * mechanism is required. */
1453
1454 /* Eviction is not expected to happen often, so a per-domain lock is
1455  * not necessary. Eviction callbacks are allowed to sleep for short
1456  * periods of time. */
1457 static DECLARE_RWSEM(dlm_callback_sem);
1458
1459 void dlm_fire_domain_eviction_callbacks(struct dlm_ctxt *dlm,
1460                                         int node_num)
1461 {
1462         struct list_head *iter;
1463         struct dlm_eviction_cb *cb;
1464
1465         down_read(&dlm_callback_sem);
1466         list_for_each(iter, &dlm->dlm_eviction_callbacks) {
1467                 cb = list_entry(iter, struct dlm_eviction_cb, ec_item);
1468
1469                 cb->ec_func(node_num, cb->ec_data);
1470         }
1471         up_read(&dlm_callback_sem);
1472 }
1473
1474 void dlm_setup_eviction_cb(struct dlm_eviction_cb *cb,
1475                            dlm_eviction_func *f,
1476                            void *data)
1477 {
1478         INIT_LIST_HEAD(&cb->ec_item);
1479         cb->ec_func = f;
1480         cb->ec_data = data;
1481 }
1482 EXPORT_SYMBOL_GPL(dlm_setup_eviction_cb);
1483
1484 void dlm_register_eviction_cb(struct dlm_ctxt *dlm,
1485                               struct dlm_eviction_cb *cb)
1486 {
1487         down_write(&dlm_callback_sem);
1488         list_add_tail(&cb->ec_item, &dlm->dlm_eviction_callbacks);
1489         up_write(&dlm_callback_sem);
1490 }
1491 EXPORT_SYMBOL_GPL(dlm_register_eviction_cb);
1492
1493 void dlm_unregister_eviction_cb(struct dlm_eviction_cb *cb)
1494 {
1495         down_write(&dlm_callback_sem);
1496         list_del_init(&cb->ec_item);
1497         up_write(&dlm_callback_sem);
1498 }
1499 EXPORT_SYMBOL_GPL(dlm_unregister_eviction_cb);
1500
1501 static int __init dlm_init(void)
1502 {
1503         int status;
1504
1505         dlm_print_version();
1506
1507         status = dlm_init_mle_cache();
1508         if (status)
1509                 return -1;
1510
1511         status = dlm_register_net_handlers();
1512         if (status) {
1513                 dlm_destroy_mle_cache();
1514                 return -1;
1515         }
1516
1517         return 0;
1518 }
1519
1520 static void __exit dlm_exit (void)
1521 {
1522         dlm_unregister_net_handlers();
1523         dlm_destroy_mle_cache();
1524 }
1525
1526 MODULE_AUTHOR("Oracle");
1527 MODULE_LICENSE("GPL");
1528
1529 module_init(dlm_init);
1530 module_exit(dlm_exit);