Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-module-and-param
[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 #include <linux/debugfs.h>
37
38 #include "cluster/heartbeat.h"
39 #include "cluster/nodemanager.h"
40 #include "cluster/tcp.h"
41
42 #include "dlmapi.h"
43 #include "dlmcommon.h"
44 #include "dlmdomain.h"
45 #include "dlmdebug.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  * ocfs2 node maps are array of long int, which limits to send them freely
54  * across the wire due to endianness issues. To workaround this, we convert
55  * long ints to byte arrays. Following 3 routines are helper functions to
56  * set/test/copy bits within those array of bytes
57  */
58 static inline void byte_set_bit(u8 nr, u8 map[])
59 {
60         map[nr >> 3] |= (1UL << (nr & 7));
61 }
62
63 static inline int byte_test_bit(u8 nr, u8 map[])
64 {
65         return ((1UL << (nr & 7)) & (map[nr >> 3])) != 0;
66 }
67
68 static inline void byte_copymap(u8 dmap[], unsigned long smap[],
69                         unsigned int sz)
70 {
71         unsigned int nn;
72
73         if (!sz)
74                 return;
75
76         memset(dmap, 0, ((sz + 7) >> 3));
77         for (nn = 0 ; nn < sz; nn++)
78                 if (test_bit(nn, smap))
79                         byte_set_bit(nn, dmap);
80 }
81
82 static void dlm_free_pagevec(void **vec, int pages)
83 {
84         while (pages--)
85                 free_page((unsigned long)vec[pages]);
86         kfree(vec);
87 }
88
89 static void **dlm_alloc_pagevec(int pages)
90 {
91         void **vec = kmalloc(pages * sizeof(void *), GFP_KERNEL);
92         int i;
93
94         if (!vec)
95                 return NULL;
96
97         for (i = 0; i < pages; i++)
98                 if (!(vec[i] = (void *)__get_free_page(GFP_KERNEL)))
99                         goto out_free;
100
101         mlog(0, "Allocated DLM hash pagevec; %d pages (%lu expected), %lu buckets per page\n",
102              pages, (unsigned long)DLM_HASH_PAGES,
103              (unsigned long)DLM_BUCKETS_PER_PAGE);
104         return vec;
105 out_free:
106         dlm_free_pagevec(vec, i);
107         return NULL;
108 }
109
110 /*
111  *
112  * spinlock lock ordering: if multiple locks are needed, obey this ordering:
113  *    dlm_domain_lock
114  *    struct dlm_ctxt->spinlock
115  *    struct dlm_lock_resource->spinlock
116  *    struct dlm_ctxt->master_lock
117  *    struct dlm_ctxt->ast_lock
118  *    dlm_master_list_entry->spinlock
119  *    dlm_lock->spinlock
120  *
121  */
122
123 DEFINE_SPINLOCK(dlm_domain_lock);
124 LIST_HEAD(dlm_domains);
125 static DECLARE_WAIT_QUEUE_HEAD(dlm_domain_events);
126
127 /*
128  * The supported protocol version for DLM communication.  Running domains
129  * will have a negotiated version with the same major number and a minor
130  * number equal or smaller.  The dlm_ctxt->dlm_locking_proto field should
131  * be used to determine what a running domain is actually using.
132  */
133 static const struct dlm_protocol_version dlm_protocol = {
134         .pv_major = 1,
135         .pv_minor = 0,
136 };
137
138 #define DLM_DOMAIN_BACKOFF_MS 200
139
140 static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
141                                   void **ret_data);
142 static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data,
143                                      void **ret_data);
144 static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data,
145                                    void **ret_data);
146 static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data,
147                                    void **ret_data);
148 static int dlm_protocol_compare(struct dlm_protocol_version *existing,
149                                 struct dlm_protocol_version *request);
150
151 static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm);
152
153 void __dlm_unhash_lockres(struct dlm_lock_resource *lockres)
154 {
155         if (!hlist_unhashed(&lockres->hash_node)) {
156                 hlist_del_init(&lockres->hash_node);
157                 dlm_lockres_put(lockres);
158         }
159 }
160
161 void __dlm_insert_lockres(struct dlm_ctxt *dlm,
162                        struct dlm_lock_resource *res)
163 {
164         struct hlist_head *bucket;
165         struct qstr *q;
166
167         assert_spin_locked(&dlm->spinlock);
168
169         q = &res->lockname;
170         bucket = dlm_lockres_hash(dlm, q->hash);
171
172         /* get a reference for our hashtable */
173         dlm_lockres_get(res);
174
175         hlist_add_head(&res->hash_node, bucket);
176 }
177
178 struct dlm_lock_resource * __dlm_lookup_lockres_full(struct dlm_ctxt *dlm,
179                                                      const char *name,
180                                                      unsigned int len,
181                                                      unsigned int hash)
182 {
183         struct hlist_head *bucket;
184         struct hlist_node *list;
185
186         mlog_entry("%.*s\n", len, name);
187
188         assert_spin_locked(&dlm->spinlock);
189
190         bucket = dlm_lockres_hash(dlm, hash);
191
192         hlist_for_each(list, bucket) {
193                 struct dlm_lock_resource *res = hlist_entry(list,
194                         struct dlm_lock_resource, hash_node);
195                 if (res->lockname.name[0] != name[0])
196                         continue;
197                 if (unlikely(res->lockname.len != len))
198                         continue;
199                 if (memcmp(res->lockname.name + 1, name + 1, len - 1))
200                         continue;
201                 dlm_lockres_get(res);
202                 return res;
203         }
204         return NULL;
205 }
206
207 /* intended to be called by functions which do not care about lock
208  * resources which are being purged (most net _handler functions).
209  * this will return NULL for any lock resource which is found but
210  * currently in the process of dropping its mastery reference.
211  * use __dlm_lookup_lockres_full when you need the lock resource
212  * regardless (e.g. dlm_get_lock_resource) */
213 struct dlm_lock_resource * __dlm_lookup_lockres(struct dlm_ctxt *dlm,
214                                                 const char *name,
215                                                 unsigned int len,
216                                                 unsigned int hash)
217 {
218         struct dlm_lock_resource *res = NULL;
219
220         mlog_entry("%.*s\n", len, name);
221
222         assert_spin_locked(&dlm->spinlock);
223
224         res = __dlm_lookup_lockres_full(dlm, name, len, hash);
225         if (res) {
226                 spin_lock(&res->spinlock);
227                 if (res->state & DLM_LOCK_RES_DROPPING_REF) {
228                         spin_unlock(&res->spinlock);
229                         dlm_lockres_put(res);
230                         return NULL;
231                 }
232                 spin_unlock(&res->spinlock);
233         }
234
235         return res;
236 }
237
238 struct dlm_lock_resource * dlm_lookup_lockres(struct dlm_ctxt *dlm,
239                                     const char *name,
240                                     unsigned int len)
241 {
242         struct dlm_lock_resource *res;
243         unsigned int hash = dlm_lockid_hash(name, len);
244
245         spin_lock(&dlm->spinlock);
246         res = __dlm_lookup_lockres(dlm, name, len, hash);
247         spin_unlock(&dlm->spinlock);
248         return res;
249 }
250
251 static struct dlm_ctxt * __dlm_lookup_domain_full(const char *domain, int len)
252 {
253         struct dlm_ctxt *tmp = NULL;
254         struct list_head *iter;
255
256         assert_spin_locked(&dlm_domain_lock);
257
258         /* tmp->name here is always NULL terminated,
259          * but domain may not be! */
260         list_for_each(iter, &dlm_domains) {
261                 tmp = list_entry (iter, struct dlm_ctxt, list);
262                 if (strlen(tmp->name) == len &&
263                     memcmp(tmp->name, domain, len)==0)
264                         break;
265                 tmp = NULL;
266         }
267
268         return tmp;
269 }
270
271 /* For null terminated domain strings ONLY */
272 static struct dlm_ctxt * __dlm_lookup_domain(const char *domain)
273 {
274         assert_spin_locked(&dlm_domain_lock);
275
276         return __dlm_lookup_domain_full(domain, strlen(domain));
277 }
278
279
280 /* returns true on one of two conditions:
281  * 1) the domain does not exist
282  * 2) the domain exists and it's state is "joined" */
283 static int dlm_wait_on_domain_helper(const char *domain)
284 {
285         int ret = 0;
286         struct dlm_ctxt *tmp = NULL;
287
288         spin_lock(&dlm_domain_lock);
289
290         tmp = __dlm_lookup_domain(domain);
291         if (!tmp)
292                 ret = 1;
293         else if (tmp->dlm_state == DLM_CTXT_JOINED)
294                 ret = 1;
295
296         spin_unlock(&dlm_domain_lock);
297         return ret;
298 }
299
300 static void dlm_free_ctxt_mem(struct dlm_ctxt *dlm)
301 {
302         dlm_destroy_debugfs_subroot(dlm);
303
304         if (dlm->lockres_hash)
305                 dlm_free_pagevec((void **)dlm->lockres_hash, DLM_HASH_PAGES);
306
307         if (dlm->master_hash)
308                 dlm_free_pagevec((void **)dlm->master_hash, DLM_HASH_PAGES);
309
310         if (dlm->name)
311                 kfree(dlm->name);
312
313         kfree(dlm);
314 }
315
316 /* A little strange - this function will be called while holding
317  * dlm_domain_lock and is expected to be holding it on the way out. We
318  * will however drop and reacquire it multiple times */
319 static void dlm_ctxt_release(struct kref *kref)
320 {
321         struct dlm_ctxt *dlm;
322
323         dlm = container_of(kref, struct dlm_ctxt, dlm_refs);
324
325         BUG_ON(dlm->num_joins);
326         BUG_ON(dlm->dlm_state == DLM_CTXT_JOINED);
327
328         /* we may still be in the list if we hit an error during join. */
329         list_del_init(&dlm->list);
330
331         spin_unlock(&dlm_domain_lock);
332
333         mlog(0, "freeing memory from domain %s\n", dlm->name);
334
335         wake_up(&dlm_domain_events);
336
337         dlm_free_ctxt_mem(dlm);
338
339         spin_lock(&dlm_domain_lock);
340 }
341
342 void dlm_put(struct dlm_ctxt *dlm)
343 {
344         spin_lock(&dlm_domain_lock);
345         kref_put(&dlm->dlm_refs, dlm_ctxt_release);
346         spin_unlock(&dlm_domain_lock);
347 }
348
349 static void __dlm_get(struct dlm_ctxt *dlm)
350 {
351         kref_get(&dlm->dlm_refs);
352 }
353
354 /* given a questionable reference to a dlm object, gets a reference if
355  * it can find it in the list, otherwise returns NULL in which case
356  * you shouldn't trust your pointer. */
357 struct dlm_ctxt *dlm_grab(struct dlm_ctxt *dlm)
358 {
359         struct list_head *iter;
360         struct dlm_ctxt *target = NULL;
361
362         spin_lock(&dlm_domain_lock);
363
364         list_for_each(iter, &dlm_domains) {
365                 target = list_entry (iter, struct dlm_ctxt, list);
366
367                 if (target == dlm) {
368                         __dlm_get(target);
369                         break;
370                 }
371
372                 target = NULL;
373         }
374
375         spin_unlock(&dlm_domain_lock);
376
377         return target;
378 }
379
380 int dlm_domain_fully_joined(struct dlm_ctxt *dlm)
381 {
382         int ret;
383
384         spin_lock(&dlm_domain_lock);
385         ret = (dlm->dlm_state == DLM_CTXT_JOINED) ||
386                 (dlm->dlm_state == DLM_CTXT_IN_SHUTDOWN);
387         spin_unlock(&dlm_domain_lock);
388
389         return ret;
390 }
391
392 static void dlm_destroy_dlm_worker(struct dlm_ctxt *dlm)
393 {
394         if (dlm->dlm_worker) {
395                 flush_workqueue(dlm->dlm_worker);
396                 destroy_workqueue(dlm->dlm_worker);
397                 dlm->dlm_worker = NULL;
398         }
399 }
400
401 static void dlm_complete_dlm_shutdown(struct dlm_ctxt *dlm)
402 {
403         dlm_unregister_domain_handlers(dlm);
404         dlm_debug_shutdown(dlm);
405         dlm_complete_thread(dlm);
406         dlm_complete_recovery_thread(dlm);
407         dlm_destroy_dlm_worker(dlm);
408
409         /* We've left the domain. Now we can take ourselves out of the
410          * list and allow the kref stuff to help us free the
411          * memory. */
412         spin_lock(&dlm_domain_lock);
413         list_del_init(&dlm->list);
414         spin_unlock(&dlm_domain_lock);
415
416         /* Wake up anyone waiting for us to remove this domain */
417         wake_up(&dlm_domain_events);
418 }
419
420 static int dlm_migrate_all_locks(struct dlm_ctxt *dlm)
421 {
422         int i, num, n, ret = 0;
423         struct dlm_lock_resource *res;
424         struct hlist_node *iter;
425         struct hlist_head *bucket;
426         int dropped;
427
428         mlog(0, "Migrating locks from domain %s\n", dlm->name);
429
430         num = 0;
431         spin_lock(&dlm->spinlock);
432         for (i = 0; i < DLM_HASH_BUCKETS; i++) {
433 redo_bucket:
434                 n = 0;
435                 bucket = dlm_lockres_hash(dlm, i);
436                 iter = bucket->first;
437                 while (iter) {
438                         n++;
439                         res = hlist_entry(iter, struct dlm_lock_resource,
440                                           hash_node);
441                         dlm_lockres_get(res);
442                         /* migrate, if necessary.  this will drop the dlm
443                          * spinlock and retake it if it does migration. */
444                         dropped = dlm_empty_lockres(dlm, res);
445
446                         spin_lock(&res->spinlock);
447                         __dlm_lockres_calc_usage(dlm, res);
448                         iter = res->hash_node.next;
449                         spin_unlock(&res->spinlock);
450
451                         dlm_lockres_put(res);
452
453                         if (dropped)
454                                 goto redo_bucket;
455                 }
456                 cond_resched_lock(&dlm->spinlock);
457                 num += n;
458                 mlog(0, "%s: touched %d lockreses in bucket %d "
459                      "(tot=%d)\n", dlm->name, n, i, num);
460         }
461         spin_unlock(&dlm->spinlock);
462         wake_up(&dlm->dlm_thread_wq);
463
464         /* let the dlm thread take care of purging, keep scanning until
465          * nothing remains in the hash */
466         if (num) {
467                 mlog(0, "%s: %d lock resources in hash last pass\n",
468                      dlm->name, num);
469                 ret = -EAGAIN;
470         }
471         mlog(0, "DONE Migrating locks from domain %s\n", dlm->name);
472         return ret;
473 }
474
475 static int dlm_no_joining_node(struct dlm_ctxt *dlm)
476 {
477         int ret;
478
479         spin_lock(&dlm->spinlock);
480         ret = dlm->joining_node == DLM_LOCK_RES_OWNER_UNKNOWN;
481         spin_unlock(&dlm->spinlock);
482
483         return ret;
484 }
485
486 static void dlm_mark_domain_leaving(struct dlm_ctxt *dlm)
487 {
488         /* Yikes, a double spinlock! I need domain_lock for the dlm
489          * state and the dlm spinlock for join state... Sorry! */
490 again:
491         spin_lock(&dlm_domain_lock);
492         spin_lock(&dlm->spinlock);
493
494         if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
495                 mlog(0, "Node %d is joining, we wait on it.\n",
496                           dlm->joining_node);
497                 spin_unlock(&dlm->spinlock);
498                 spin_unlock(&dlm_domain_lock);
499
500                 wait_event(dlm->dlm_join_events, dlm_no_joining_node(dlm));
501                 goto again;
502         }
503
504         dlm->dlm_state = DLM_CTXT_LEAVING;
505         spin_unlock(&dlm->spinlock);
506         spin_unlock(&dlm_domain_lock);
507 }
508
509 static void __dlm_print_nodes(struct dlm_ctxt *dlm)
510 {
511         int node = -1;
512
513         assert_spin_locked(&dlm->spinlock);
514
515         printk(KERN_INFO "ocfs2_dlm: Nodes in domain (\"%s\"): ", dlm->name);
516
517         while ((node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES,
518                                      node + 1)) < O2NM_MAX_NODES) {
519                 printk("%d ", node);
520         }
521         printk("\n");
522 }
523
524 static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data,
525                                    void **ret_data)
526 {
527         struct dlm_ctxt *dlm = data;
528         unsigned int node;
529         struct dlm_exit_domain *exit_msg = (struct dlm_exit_domain *) msg->buf;
530
531         mlog_entry("%p %u %p", msg, len, data);
532
533         if (!dlm_grab(dlm))
534                 return 0;
535
536         node = exit_msg->node_idx;
537
538         printk(KERN_INFO "ocfs2_dlm: Node %u leaves domain %s\n", node, dlm->name);
539
540         spin_lock(&dlm->spinlock);
541         clear_bit(node, dlm->domain_map);
542         __dlm_print_nodes(dlm);
543
544         /* notify anything attached to the heartbeat events */
545         dlm_hb_event_notify_attached(dlm, node, 0);
546
547         spin_unlock(&dlm->spinlock);
548
549         dlm_put(dlm);
550
551         return 0;
552 }
553
554 static int dlm_send_one_domain_exit(struct dlm_ctxt *dlm,
555                                     unsigned int node)
556 {
557         int status;
558         struct dlm_exit_domain leave_msg;
559
560         mlog(0, "Asking node %u if we can leave the domain %s me = %u\n",
561                   node, dlm->name, dlm->node_num);
562
563         memset(&leave_msg, 0, sizeof(leave_msg));
564         leave_msg.node_idx = dlm->node_num;
565
566         status = o2net_send_message(DLM_EXIT_DOMAIN_MSG, dlm->key,
567                                     &leave_msg, sizeof(leave_msg), node,
568                                     NULL);
569
570         mlog(0, "status return %d from o2net_send_message\n", status);
571
572         return status;
573 }
574
575
576 static void dlm_leave_domain(struct dlm_ctxt *dlm)
577 {
578         int node, clear_node, status;
579
580         /* At this point we've migrated away all our locks and won't
581          * accept mastership of new ones. The dlm is responsible for
582          * almost nothing now. We make sure not to confuse any joining
583          * nodes and then commence shutdown procedure. */
584
585         spin_lock(&dlm->spinlock);
586         /* Clear ourselves from the domain map */
587         clear_bit(dlm->node_num, dlm->domain_map);
588         while ((node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES,
589                                      0)) < O2NM_MAX_NODES) {
590                 /* Drop the dlm spinlock. This is safe wrt the domain_map.
591                  * -nodes cannot be added now as the
592                  *   query_join_handlers knows to respond with OK_NO_MAP
593                  * -we catch the right network errors if a node is
594                  *   removed from the map while we're sending him the
595                  *   exit message. */
596                 spin_unlock(&dlm->spinlock);
597
598                 clear_node = 1;
599
600                 status = dlm_send_one_domain_exit(dlm, node);
601                 if (status < 0 &&
602                     status != -ENOPROTOOPT &&
603                     status != -ENOTCONN) {
604                         mlog(ML_NOTICE, "Error %d sending domain exit message "
605                              "to node %d\n", status, node);
606
607                         /* Not sure what to do here but lets sleep for
608                          * a bit in case this was a transient
609                          * error... */
610                         msleep(DLM_DOMAIN_BACKOFF_MS);
611                         clear_node = 0;
612                 }
613
614                 spin_lock(&dlm->spinlock);
615                 /* If we're not clearing the node bit then we intend
616                  * to loop back around to try again. */
617                 if (clear_node)
618                         clear_bit(node, dlm->domain_map);
619         }
620         spin_unlock(&dlm->spinlock);
621 }
622
623 int dlm_joined(struct dlm_ctxt *dlm)
624 {
625         int ret = 0;
626
627         spin_lock(&dlm_domain_lock);
628
629         if (dlm->dlm_state == DLM_CTXT_JOINED)
630                 ret = 1;
631
632         spin_unlock(&dlm_domain_lock);
633
634         return ret;
635 }
636
637 int dlm_shutting_down(struct dlm_ctxt *dlm)
638 {
639         int ret = 0;
640
641         spin_lock(&dlm_domain_lock);
642
643         if (dlm->dlm_state == DLM_CTXT_IN_SHUTDOWN)
644                 ret = 1;
645
646         spin_unlock(&dlm_domain_lock);
647
648         return ret;
649 }
650
651 void dlm_unregister_domain(struct dlm_ctxt *dlm)
652 {
653         int leave = 0;
654         struct dlm_lock_resource *res;
655
656         spin_lock(&dlm_domain_lock);
657         BUG_ON(dlm->dlm_state != DLM_CTXT_JOINED);
658         BUG_ON(!dlm->num_joins);
659
660         dlm->num_joins--;
661         if (!dlm->num_joins) {
662                 /* We mark it "in shutdown" now so new register
663                  * requests wait until we've completely left the
664                  * domain. Don't use DLM_CTXT_LEAVING yet as we still
665                  * want new domain joins to communicate with us at
666                  * least until we've completed migration of our
667                  * resources. */
668                 dlm->dlm_state = DLM_CTXT_IN_SHUTDOWN;
669                 leave = 1;
670         }
671         spin_unlock(&dlm_domain_lock);
672
673         if (leave) {
674                 mlog(0, "shutting down domain %s\n", dlm->name);
675
676                 /* We changed dlm state, notify the thread */
677                 dlm_kick_thread(dlm, NULL);
678
679                 while (dlm_migrate_all_locks(dlm)) {
680                         /* Give dlm_thread time to purge the lockres' */
681                         msleep(500);
682                         mlog(0, "%s: more migration to do\n", dlm->name);
683                 }
684
685                 /* This list should be empty. If not, print remaining lockres */
686                 if (!list_empty(&dlm->tracking_list)) {
687                         mlog(ML_ERROR, "Following lockres' are still on the "
688                              "tracking list:\n");
689                         list_for_each_entry(res, &dlm->tracking_list, tracking)
690                                 dlm_print_one_lock_resource(res);
691                 }
692
693                 dlm_mark_domain_leaving(dlm);
694                 dlm_leave_domain(dlm);
695                 dlm_complete_dlm_shutdown(dlm);
696         }
697         dlm_put(dlm);
698 }
699 EXPORT_SYMBOL_GPL(dlm_unregister_domain);
700
701 static int dlm_query_join_proto_check(char *proto_type, int node,
702                                       struct dlm_protocol_version *ours,
703                                       struct dlm_protocol_version *request)
704 {
705         int rc;
706         struct dlm_protocol_version proto = *request;
707
708         if (!dlm_protocol_compare(ours, &proto)) {
709                 mlog(0,
710                      "node %u wanted to join with %s locking protocol "
711                      "%u.%u, we respond with %u.%u\n",
712                      node, proto_type,
713                      request->pv_major,
714                      request->pv_minor,
715                      proto.pv_major, proto.pv_minor);
716                 request->pv_minor = proto.pv_minor;
717                 rc = 0;
718         } else {
719                 mlog(ML_NOTICE,
720                      "Node %u wanted to join with %s locking "
721                      "protocol %u.%u, but we have %u.%u, disallowing\n",
722                      node, proto_type,
723                      request->pv_major,
724                      request->pv_minor,
725                      ours->pv_major,
726                      ours->pv_minor);
727                 rc = 1;
728         }
729
730         return rc;
731 }
732
733 /*
734  * struct dlm_query_join_packet is made up of four one-byte fields.  They
735  * are effectively in big-endian order already.  However, little-endian
736  * machines swap them before putting the packet on the wire (because
737  * query_join's response is a status, and that status is treated as a u32
738  * on the wire).  Thus, a big-endian and little-endian machines will treat
739  * this structure differently.
740  *
741  * The solution is to have little-endian machines swap the structure when
742  * converting from the structure to the u32 representation.  This will
743  * result in the structure having the correct format on the wire no matter
744  * the host endian format.
745  */
746 static void dlm_query_join_packet_to_wire(struct dlm_query_join_packet *packet,
747                                           u32 *wire)
748 {
749         union dlm_query_join_response response;
750
751         response.packet = *packet;
752         *wire = cpu_to_be32(response.intval);
753 }
754
755 static void dlm_query_join_wire_to_packet(u32 wire,
756                                           struct dlm_query_join_packet *packet)
757 {
758         union dlm_query_join_response response;
759
760         response.intval = cpu_to_be32(wire);
761         *packet = response.packet;
762 }
763
764 static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
765                                   void **ret_data)
766 {
767         struct dlm_query_join_request *query;
768         struct dlm_query_join_packet packet = {
769                 .code = JOIN_DISALLOW,
770         };
771         struct dlm_ctxt *dlm = NULL;
772         u32 response;
773         u8 nodenum;
774
775         query = (struct dlm_query_join_request *) msg->buf;
776
777         mlog(0, "node %u wants to join domain %s\n", query->node_idx,
778                   query->domain);
779
780         /*
781          * If heartbeat doesn't consider the node live, tell it
782          * to back off and try again.  This gives heartbeat a chance
783          * to catch up.
784          */
785         if (!o2hb_check_node_heartbeating(query->node_idx)) {
786                 mlog(0, "node %u is not in our live map yet\n",
787                      query->node_idx);
788
789                 packet.code = JOIN_DISALLOW;
790                 goto respond;
791         }
792
793         packet.code = JOIN_OK_NO_MAP;
794
795         spin_lock(&dlm_domain_lock);
796         dlm = __dlm_lookup_domain_full(query->domain, query->name_len);
797         if (!dlm)
798                 goto unlock_respond;
799
800         /*
801          * There is a small window where the joining node may not see the
802          * node(s) that just left but still part of the cluster. DISALLOW
803          * join request if joining node has different node map.
804          */
805         nodenum=0;
806         while (nodenum < O2NM_MAX_NODES) {
807                 if (test_bit(nodenum, dlm->domain_map)) {
808                         if (!byte_test_bit(nodenum, query->node_map)) {
809                                 mlog(0, "disallow join as node %u does not "
810                                      "have node %u in its nodemap\n",
811                                      query->node_idx, nodenum);
812                                 packet.code = JOIN_DISALLOW;
813                                 goto unlock_respond;
814                         }
815                 }
816                 nodenum++;
817         }
818
819         /* Once the dlm ctxt is marked as leaving then we don't want
820          * to be put in someone's domain map. 
821          * Also, explicitly disallow joining at certain troublesome
822          * times (ie. during recovery). */
823         if (dlm && dlm->dlm_state != DLM_CTXT_LEAVING) {
824                 int bit = query->node_idx;
825                 spin_lock(&dlm->spinlock);
826
827                 if (dlm->dlm_state == DLM_CTXT_NEW &&
828                     dlm->joining_node == DLM_LOCK_RES_OWNER_UNKNOWN) {
829                         /*If this is a brand new context and we
830                          * haven't started our join process yet, then
831                          * the other node won the race. */
832                         packet.code = JOIN_OK_NO_MAP;
833                 } else if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
834                         /* Disallow parallel joins. */
835                         packet.code = JOIN_DISALLOW;
836                 } else if (dlm->reco.state & DLM_RECO_STATE_ACTIVE) {
837                         mlog(0, "node %u trying to join, but recovery "
838                              "is ongoing.\n", bit);
839                         packet.code = JOIN_DISALLOW;
840                 } else if (test_bit(bit, dlm->recovery_map)) {
841                         mlog(0, "node %u trying to join, but it "
842                              "still needs recovery.\n", bit);
843                         packet.code = JOIN_DISALLOW;
844                 } else if (test_bit(bit, dlm->domain_map)) {
845                         mlog(0, "node %u trying to join, but it "
846                              "is still in the domain! needs recovery?\n",
847                              bit);
848                         packet.code = JOIN_DISALLOW;
849                 } else {
850                         /* Alright we're fully a part of this domain
851                          * so we keep some state as to who's joining
852                          * and indicate to him that needs to be fixed
853                          * up. */
854
855                         /* Make sure we speak compatible locking protocols.  */
856                         if (dlm_query_join_proto_check("DLM", bit,
857                                                        &dlm->dlm_locking_proto,
858                                                        &query->dlm_proto)) {
859                                 packet.code = JOIN_PROTOCOL_MISMATCH;
860                         } else if (dlm_query_join_proto_check("fs", bit,
861                                                               &dlm->fs_locking_proto,
862                                                               &query->fs_proto)) {
863                                 packet.code = JOIN_PROTOCOL_MISMATCH;
864                         } else {
865                                 packet.dlm_minor = query->dlm_proto.pv_minor;
866                                 packet.fs_minor = query->fs_proto.pv_minor;
867                                 packet.code = JOIN_OK;
868                                 __dlm_set_joining_node(dlm, query->node_idx);
869                         }
870                 }
871
872                 spin_unlock(&dlm->spinlock);
873         }
874 unlock_respond:
875         spin_unlock(&dlm_domain_lock);
876
877 respond:
878         mlog(0, "We respond with %u\n", packet.code);
879
880         dlm_query_join_packet_to_wire(&packet, &response);
881         return response;
882 }
883
884 static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data,
885                                      void **ret_data)
886 {
887         struct dlm_assert_joined *assert;
888         struct dlm_ctxt *dlm = NULL;
889
890         assert = (struct dlm_assert_joined *) msg->buf;
891
892         mlog(0, "node %u asserts join on domain %s\n", assert->node_idx,
893                   assert->domain);
894
895         spin_lock(&dlm_domain_lock);
896         dlm = __dlm_lookup_domain_full(assert->domain, assert->name_len);
897         /* XXX should we consider no dlm ctxt an error? */
898         if (dlm) {
899                 spin_lock(&dlm->spinlock);
900
901                 /* Alright, this node has officially joined our
902                  * domain. Set him in the map and clean up our
903                  * leftover join state. */
904                 BUG_ON(dlm->joining_node != assert->node_idx);
905                 set_bit(assert->node_idx, dlm->domain_map);
906                 __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
907
908                 printk(KERN_INFO "ocfs2_dlm: Node %u joins domain %s\n",
909                        assert->node_idx, dlm->name);
910                 __dlm_print_nodes(dlm);
911
912                 /* notify anything attached to the heartbeat events */
913                 dlm_hb_event_notify_attached(dlm, assert->node_idx, 1);
914
915                 spin_unlock(&dlm->spinlock);
916         }
917         spin_unlock(&dlm_domain_lock);
918
919         return 0;
920 }
921
922 static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data,
923                                    void **ret_data)
924 {
925         struct dlm_cancel_join *cancel;
926         struct dlm_ctxt *dlm = NULL;
927
928         cancel = (struct dlm_cancel_join *) msg->buf;
929
930         mlog(0, "node %u cancels join on domain %s\n", cancel->node_idx,
931                   cancel->domain);
932
933         spin_lock(&dlm_domain_lock);
934         dlm = __dlm_lookup_domain_full(cancel->domain, cancel->name_len);
935
936         if (dlm) {
937                 spin_lock(&dlm->spinlock);
938
939                 /* Yikes, this guy wants to cancel his join. No
940                  * problem, we simply cleanup our join state. */
941                 BUG_ON(dlm->joining_node != cancel->node_idx);
942                 __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
943
944                 spin_unlock(&dlm->spinlock);
945         }
946         spin_unlock(&dlm_domain_lock);
947
948         return 0;
949 }
950
951 static int dlm_send_one_join_cancel(struct dlm_ctxt *dlm,
952                                     unsigned int node)
953 {
954         int status;
955         struct dlm_cancel_join cancel_msg;
956
957         memset(&cancel_msg, 0, sizeof(cancel_msg));
958         cancel_msg.node_idx = dlm->node_num;
959         cancel_msg.name_len = strlen(dlm->name);
960         memcpy(cancel_msg.domain, dlm->name, cancel_msg.name_len);
961
962         status = o2net_send_message(DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
963                                     &cancel_msg, sizeof(cancel_msg), node,
964                                     NULL);
965         if (status < 0) {
966                 mlog_errno(status);
967                 goto bail;
968         }
969
970 bail:
971         return status;
972 }
973
974 /* map_size should be in bytes. */
975 static int dlm_send_join_cancels(struct dlm_ctxt *dlm,
976                                  unsigned long *node_map,
977                                  unsigned int map_size)
978 {
979         int status, tmpstat;
980         unsigned int node;
981
982         if (map_size != (BITS_TO_LONGS(O2NM_MAX_NODES) *
983                          sizeof(unsigned long))) {
984                 mlog(ML_ERROR,
985                      "map_size %u != BITS_TO_LONGS(O2NM_MAX_NODES) %u\n",
986                      map_size, (unsigned)BITS_TO_LONGS(O2NM_MAX_NODES));
987                 return -EINVAL;
988         }
989
990         status = 0;
991         node = -1;
992         while ((node = find_next_bit(node_map, O2NM_MAX_NODES,
993                                      node + 1)) < O2NM_MAX_NODES) {
994                 if (node == dlm->node_num)
995                         continue;
996
997                 tmpstat = dlm_send_one_join_cancel(dlm, node);
998                 if (tmpstat) {
999                         mlog(ML_ERROR, "Error return %d cancelling join on "
1000                              "node %d\n", tmpstat, node);
1001                         if (!status)
1002                                 status = tmpstat;
1003                 }
1004         }
1005
1006         if (status)
1007                 mlog_errno(status);
1008         return status;
1009 }
1010
1011 static int dlm_request_join(struct dlm_ctxt *dlm,
1012                             int node,
1013                             enum dlm_query_join_response_code *response)
1014 {
1015         int status;
1016         struct dlm_query_join_request join_msg;
1017         struct dlm_query_join_packet packet;
1018         u32 join_resp;
1019
1020         mlog(0, "querying node %d\n", node);
1021
1022         memset(&join_msg, 0, sizeof(join_msg));
1023         join_msg.node_idx = dlm->node_num;
1024         join_msg.name_len = strlen(dlm->name);
1025         memcpy(join_msg.domain, dlm->name, join_msg.name_len);
1026         join_msg.dlm_proto = dlm->dlm_locking_proto;
1027         join_msg.fs_proto = dlm->fs_locking_proto;
1028
1029         /* copy live node map to join message */
1030         byte_copymap(join_msg.node_map, dlm->live_nodes_map, O2NM_MAX_NODES);
1031
1032         status = o2net_send_message(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY, &join_msg,
1033                                     sizeof(join_msg), node,
1034                                     &join_resp);
1035         if (status < 0 && status != -ENOPROTOOPT) {
1036                 mlog_errno(status);
1037                 goto bail;
1038         }
1039         dlm_query_join_wire_to_packet(join_resp, &packet);
1040
1041         /* -ENOPROTOOPT from the net code means the other side isn't
1042             listening for our message type -- that's fine, it means
1043             his dlm isn't up, so we can consider him a 'yes' but not
1044             joined into the domain.  */
1045         if (status == -ENOPROTOOPT) {
1046                 status = 0;
1047                 *response = JOIN_OK_NO_MAP;
1048         } else if (packet.code == JOIN_DISALLOW ||
1049                    packet.code == JOIN_OK_NO_MAP) {
1050                 *response = packet.code;
1051         } else if (packet.code == JOIN_PROTOCOL_MISMATCH) {
1052                 mlog(ML_NOTICE,
1053                      "This node requested DLM locking protocol %u.%u and "
1054                      "filesystem locking protocol %u.%u.  At least one of "
1055                      "the protocol versions on node %d is not compatible, "
1056                      "disconnecting\n",
1057                      dlm->dlm_locking_proto.pv_major,
1058                      dlm->dlm_locking_proto.pv_minor,
1059                      dlm->fs_locking_proto.pv_major,
1060                      dlm->fs_locking_proto.pv_minor,
1061                      node);
1062                 status = -EPROTO;
1063                 *response = packet.code;
1064         } else if (packet.code == JOIN_OK) {
1065                 *response = packet.code;
1066                 /* Use the same locking protocol as the remote node */
1067                 dlm->dlm_locking_proto.pv_minor = packet.dlm_minor;
1068                 dlm->fs_locking_proto.pv_minor = packet.fs_minor;
1069                 mlog(0,
1070                      "Node %d responds JOIN_OK with DLM locking protocol "
1071                      "%u.%u and fs locking protocol %u.%u\n",
1072                      node,
1073                      dlm->dlm_locking_proto.pv_major,
1074                      dlm->dlm_locking_proto.pv_minor,
1075                      dlm->fs_locking_proto.pv_major,
1076                      dlm->fs_locking_proto.pv_minor);
1077         } else {
1078                 status = -EINVAL;
1079                 mlog(ML_ERROR, "invalid response %d from node %u\n",
1080                      packet.code, node);
1081         }
1082
1083         mlog(0, "status %d, node %d response is %d\n", status, node,
1084              *response);
1085
1086 bail:
1087         return status;
1088 }
1089
1090 static int dlm_send_one_join_assert(struct dlm_ctxt *dlm,
1091                                     unsigned int node)
1092 {
1093         int status;
1094         struct dlm_assert_joined assert_msg;
1095
1096         mlog(0, "Sending join assert to node %u\n", node);
1097
1098         memset(&assert_msg, 0, sizeof(assert_msg));
1099         assert_msg.node_idx = dlm->node_num;
1100         assert_msg.name_len = strlen(dlm->name);
1101         memcpy(assert_msg.domain, dlm->name, assert_msg.name_len);
1102
1103         status = o2net_send_message(DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
1104                                     &assert_msg, sizeof(assert_msg), node,
1105                                     NULL);
1106         if (status < 0)
1107                 mlog_errno(status);
1108
1109         return status;
1110 }
1111
1112 static void dlm_send_join_asserts(struct dlm_ctxt *dlm,
1113                                   unsigned long *node_map)
1114 {
1115         int status, node, live;
1116
1117         status = 0;
1118         node = -1;
1119         while ((node = find_next_bit(node_map, O2NM_MAX_NODES,
1120                                      node + 1)) < O2NM_MAX_NODES) {
1121                 if (node == dlm->node_num)
1122                         continue;
1123
1124                 do {
1125                         /* It is very important that this message be
1126                          * received so we spin until either the node
1127                          * has died or it gets the message. */
1128                         status = dlm_send_one_join_assert(dlm, node);
1129
1130                         spin_lock(&dlm->spinlock);
1131                         live = test_bit(node, dlm->live_nodes_map);
1132                         spin_unlock(&dlm->spinlock);
1133
1134                         if (status) {
1135                                 mlog(ML_ERROR, "Error return %d asserting "
1136                                      "join on node %d\n", status, node);
1137
1138                                 /* give us some time between errors... */
1139                                 if (live)
1140                                         msleep(DLM_DOMAIN_BACKOFF_MS);
1141                         }
1142                 } while (status && live);
1143         }
1144 }
1145
1146 struct domain_join_ctxt {
1147         unsigned long live_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1148         unsigned long yes_resp_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1149 };
1150
1151 static int dlm_should_restart_join(struct dlm_ctxt *dlm,
1152                                    struct domain_join_ctxt *ctxt,
1153                                    enum dlm_query_join_response_code response)
1154 {
1155         int ret;
1156
1157         if (response == JOIN_DISALLOW) {
1158                 mlog(0, "Latest response of disallow -- should restart\n");
1159                 return 1;
1160         }
1161
1162         spin_lock(&dlm->spinlock);
1163         /* For now, we restart the process if the node maps have
1164          * changed at all */
1165         ret = memcmp(ctxt->live_map, dlm->live_nodes_map,
1166                      sizeof(dlm->live_nodes_map));
1167         spin_unlock(&dlm->spinlock);
1168
1169         if (ret)
1170                 mlog(0, "Node maps changed -- should restart\n");
1171
1172         return ret;
1173 }
1174
1175 static int dlm_try_to_join_domain(struct dlm_ctxt *dlm)
1176 {
1177         int status = 0, tmpstat, node;
1178         struct domain_join_ctxt *ctxt;
1179         enum dlm_query_join_response_code response = JOIN_DISALLOW;
1180
1181         mlog_entry("%p", dlm);
1182
1183         ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL);
1184         if (!ctxt) {
1185                 status = -ENOMEM;
1186                 mlog_errno(status);
1187                 goto bail;
1188         }
1189
1190         /* group sem locking should work for us here -- we're already
1191          * registered for heartbeat events so filling this should be
1192          * atomic wrt getting those handlers called. */
1193         o2hb_fill_node_map(dlm->live_nodes_map, sizeof(dlm->live_nodes_map));
1194
1195         spin_lock(&dlm->spinlock);
1196         memcpy(ctxt->live_map, dlm->live_nodes_map, sizeof(ctxt->live_map));
1197
1198         __dlm_set_joining_node(dlm, dlm->node_num);
1199
1200         spin_unlock(&dlm->spinlock);
1201
1202         node = -1;
1203         while ((node = find_next_bit(ctxt->live_map, O2NM_MAX_NODES,
1204                                      node + 1)) < O2NM_MAX_NODES) {
1205                 if (node == dlm->node_num)
1206                         continue;
1207
1208                 status = dlm_request_join(dlm, node, &response);
1209                 if (status < 0) {
1210                         mlog_errno(status);
1211                         goto bail;
1212                 }
1213
1214                 /* Ok, either we got a response or the node doesn't have a
1215                  * dlm up. */
1216                 if (response == JOIN_OK)
1217                         set_bit(node, ctxt->yes_resp_map);
1218
1219                 if (dlm_should_restart_join(dlm, ctxt, response)) {
1220                         status = -EAGAIN;
1221                         goto bail;
1222                 }
1223         }
1224
1225         mlog(0, "Yay, done querying nodes!\n");
1226
1227         /* Yay, everyone agree's we can join the domain. My domain is
1228          * comprised of all nodes who were put in the
1229          * yes_resp_map. Copy that into our domain map and send a join
1230          * assert message to clean up everyone elses state. */
1231         spin_lock(&dlm->spinlock);
1232         memcpy(dlm->domain_map, ctxt->yes_resp_map,
1233                sizeof(ctxt->yes_resp_map));
1234         set_bit(dlm->node_num, dlm->domain_map);
1235         spin_unlock(&dlm->spinlock);
1236
1237         dlm_send_join_asserts(dlm, ctxt->yes_resp_map);
1238
1239         /* Joined state *must* be set before the joining node
1240          * information, otherwise the query_join handler may read no
1241          * current joiner but a state of NEW and tell joining nodes
1242          * we're not in the domain. */
1243         spin_lock(&dlm_domain_lock);
1244         dlm->dlm_state = DLM_CTXT_JOINED;
1245         dlm->num_joins++;
1246         spin_unlock(&dlm_domain_lock);
1247
1248 bail:
1249         spin_lock(&dlm->spinlock);
1250         __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
1251         if (!status)
1252                 __dlm_print_nodes(dlm);
1253         spin_unlock(&dlm->spinlock);
1254
1255         if (ctxt) {
1256                 /* Do we need to send a cancel message to any nodes? */
1257                 if (status < 0) {
1258                         tmpstat = dlm_send_join_cancels(dlm,
1259                                                         ctxt->yes_resp_map,
1260                                                         sizeof(ctxt->yes_resp_map));
1261                         if (tmpstat < 0)
1262                                 mlog_errno(tmpstat);
1263                 }
1264                 kfree(ctxt);
1265         }
1266
1267         mlog(0, "returning %d\n", status);
1268         return status;
1269 }
1270
1271 static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm)
1272 {
1273         o2hb_unregister_callback(NULL, &dlm->dlm_hb_up);
1274         o2hb_unregister_callback(NULL, &dlm->dlm_hb_down);
1275         o2net_unregister_handler_list(&dlm->dlm_domain_handlers);
1276 }
1277
1278 static int dlm_register_domain_handlers(struct dlm_ctxt *dlm)
1279 {
1280         int status;
1281
1282         mlog(0, "registering handlers.\n");
1283
1284         o2hb_setup_callback(&dlm->dlm_hb_down, O2HB_NODE_DOWN_CB,
1285                             dlm_hb_node_down_cb, dlm, DLM_HB_NODE_DOWN_PRI);
1286         status = o2hb_register_callback(NULL, &dlm->dlm_hb_down);
1287         if (status)
1288                 goto bail;
1289
1290         o2hb_setup_callback(&dlm->dlm_hb_up, O2HB_NODE_UP_CB,
1291                             dlm_hb_node_up_cb, dlm, DLM_HB_NODE_UP_PRI);
1292         status = o2hb_register_callback(NULL, &dlm->dlm_hb_up);
1293         if (status)
1294                 goto bail;
1295
1296         status = o2net_register_handler(DLM_MASTER_REQUEST_MSG, dlm->key,
1297                                         sizeof(struct dlm_master_request),
1298                                         dlm_master_request_handler,
1299                                         dlm, NULL, &dlm->dlm_domain_handlers);
1300         if (status)
1301                 goto bail;
1302
1303         status = o2net_register_handler(DLM_ASSERT_MASTER_MSG, dlm->key,
1304                                         sizeof(struct dlm_assert_master),
1305                                         dlm_assert_master_handler,
1306                                         dlm, dlm_assert_master_post_handler,
1307                                         &dlm->dlm_domain_handlers);
1308         if (status)
1309                 goto bail;
1310
1311         status = o2net_register_handler(DLM_CREATE_LOCK_MSG, dlm->key,
1312                                         sizeof(struct dlm_create_lock),
1313                                         dlm_create_lock_handler,
1314                                         dlm, NULL, &dlm->dlm_domain_handlers);
1315         if (status)
1316                 goto bail;
1317
1318         status = o2net_register_handler(DLM_CONVERT_LOCK_MSG, dlm->key,
1319                                         DLM_CONVERT_LOCK_MAX_LEN,
1320                                         dlm_convert_lock_handler,
1321                                         dlm, NULL, &dlm->dlm_domain_handlers);
1322         if (status)
1323                 goto bail;
1324
1325         status = o2net_register_handler(DLM_UNLOCK_LOCK_MSG, dlm->key,
1326                                         DLM_UNLOCK_LOCK_MAX_LEN,
1327                                         dlm_unlock_lock_handler,
1328                                         dlm, NULL, &dlm->dlm_domain_handlers);
1329         if (status)
1330                 goto bail;
1331
1332         status = o2net_register_handler(DLM_PROXY_AST_MSG, dlm->key,
1333                                         DLM_PROXY_AST_MAX_LEN,
1334                                         dlm_proxy_ast_handler,
1335                                         dlm, NULL, &dlm->dlm_domain_handlers);
1336         if (status)
1337                 goto bail;
1338
1339         status = o2net_register_handler(DLM_EXIT_DOMAIN_MSG, dlm->key,
1340                                         sizeof(struct dlm_exit_domain),
1341                                         dlm_exit_domain_handler,
1342                                         dlm, NULL, &dlm->dlm_domain_handlers);
1343         if (status)
1344                 goto bail;
1345
1346         status = o2net_register_handler(DLM_DEREF_LOCKRES_MSG, dlm->key,
1347                                         sizeof(struct dlm_deref_lockres),
1348                                         dlm_deref_lockres_handler,
1349                                         dlm, NULL, &dlm->dlm_domain_handlers);
1350         if (status)
1351                 goto bail;
1352
1353         status = o2net_register_handler(DLM_MIGRATE_REQUEST_MSG, dlm->key,
1354                                         sizeof(struct dlm_migrate_request),
1355                                         dlm_migrate_request_handler,
1356                                         dlm, NULL, &dlm->dlm_domain_handlers);
1357         if (status)
1358                 goto bail;
1359
1360         status = o2net_register_handler(DLM_MIG_LOCKRES_MSG, dlm->key,
1361                                         DLM_MIG_LOCKRES_MAX_LEN,
1362                                         dlm_mig_lockres_handler,
1363                                         dlm, NULL, &dlm->dlm_domain_handlers);
1364         if (status)
1365                 goto bail;
1366
1367         status = o2net_register_handler(DLM_MASTER_REQUERY_MSG, dlm->key,
1368                                         sizeof(struct dlm_master_requery),
1369                                         dlm_master_requery_handler,
1370                                         dlm, NULL, &dlm->dlm_domain_handlers);
1371         if (status)
1372                 goto bail;
1373
1374         status = o2net_register_handler(DLM_LOCK_REQUEST_MSG, dlm->key,
1375                                         sizeof(struct dlm_lock_request),
1376                                         dlm_request_all_locks_handler,
1377                                         dlm, NULL, &dlm->dlm_domain_handlers);
1378         if (status)
1379                 goto bail;
1380
1381         status = o2net_register_handler(DLM_RECO_DATA_DONE_MSG, dlm->key,
1382                                         sizeof(struct dlm_reco_data_done),
1383                                         dlm_reco_data_done_handler,
1384                                         dlm, NULL, &dlm->dlm_domain_handlers);
1385         if (status)
1386                 goto bail;
1387
1388         status = o2net_register_handler(DLM_BEGIN_RECO_MSG, dlm->key,
1389                                         sizeof(struct dlm_begin_reco),
1390                                         dlm_begin_reco_handler,
1391                                         dlm, NULL, &dlm->dlm_domain_handlers);
1392         if (status)
1393                 goto bail;
1394
1395         status = o2net_register_handler(DLM_FINALIZE_RECO_MSG, dlm->key,
1396                                         sizeof(struct dlm_finalize_reco),
1397                                         dlm_finalize_reco_handler,
1398                                         dlm, NULL, &dlm->dlm_domain_handlers);
1399         if (status)
1400                 goto bail;
1401
1402 bail:
1403         if (status)
1404                 dlm_unregister_domain_handlers(dlm);
1405
1406         return status;
1407 }
1408
1409 static int dlm_join_domain(struct dlm_ctxt *dlm)
1410 {
1411         int status;
1412         unsigned int backoff;
1413         unsigned int total_backoff = 0;
1414
1415         BUG_ON(!dlm);
1416
1417         mlog(0, "Join domain %s\n", dlm->name);
1418
1419         status = dlm_register_domain_handlers(dlm);
1420         if (status) {
1421                 mlog_errno(status);
1422                 goto bail;
1423         }
1424
1425         status = dlm_debug_init(dlm);
1426         if (status < 0) {
1427                 mlog_errno(status);
1428                 goto bail;
1429         }
1430
1431         status = dlm_launch_thread(dlm);
1432         if (status < 0) {
1433                 mlog_errno(status);
1434                 goto bail;
1435         }
1436
1437         status = dlm_launch_recovery_thread(dlm);
1438         if (status < 0) {
1439                 mlog_errno(status);
1440                 goto bail;
1441         }
1442
1443         dlm->dlm_worker = create_singlethread_workqueue("dlm_wq");
1444         if (!dlm->dlm_worker) {
1445                 status = -ENOMEM;
1446                 mlog_errno(status);
1447                 goto bail;
1448         }
1449
1450         do {
1451                 status = dlm_try_to_join_domain(dlm);
1452
1453                 /* If we're racing another node to the join, then we
1454                  * need to back off temporarily and let them
1455                  * complete. */
1456 #define DLM_JOIN_TIMEOUT_MSECS  90000
1457                 if (status == -EAGAIN) {
1458                         if (signal_pending(current)) {
1459                                 status = -ERESTARTSYS;
1460                                 goto bail;
1461                         }
1462
1463                         if (total_backoff >
1464                             msecs_to_jiffies(DLM_JOIN_TIMEOUT_MSECS)) {
1465                                 status = -ERESTARTSYS;
1466                                 mlog(ML_NOTICE, "Timed out joining dlm domain "
1467                                      "%s after %u msecs\n", dlm->name,
1468                                      jiffies_to_msecs(total_backoff));
1469                                 goto bail;
1470                         }
1471
1472                         /*
1473                          * <chip> After you!
1474                          * <dale> No, after you!
1475                          * <chip> I insist!
1476                          * <dale> But you first!
1477                          * ...
1478                          */
1479                         backoff = (unsigned int)(jiffies & 0x3);
1480                         backoff *= DLM_DOMAIN_BACKOFF_MS;
1481                         total_backoff += backoff;
1482                         mlog(0, "backoff %d\n", backoff);
1483                         msleep(backoff);
1484                 }
1485         } while (status == -EAGAIN);
1486
1487         if (status < 0) {
1488                 mlog_errno(status);
1489                 goto bail;
1490         }
1491
1492         status = 0;
1493 bail:
1494         wake_up(&dlm_domain_events);
1495
1496         if (status) {
1497                 dlm_unregister_domain_handlers(dlm);
1498                 dlm_debug_shutdown(dlm);
1499                 dlm_complete_thread(dlm);
1500                 dlm_complete_recovery_thread(dlm);
1501                 dlm_destroy_dlm_worker(dlm);
1502         }
1503
1504         return status;
1505 }
1506
1507 static struct dlm_ctxt *dlm_alloc_ctxt(const char *domain,
1508                                 u32 key)
1509 {
1510         int i;
1511         int ret;
1512         struct dlm_ctxt *dlm = NULL;
1513
1514         dlm = kzalloc(sizeof(*dlm), GFP_KERNEL);
1515         if (!dlm) {
1516                 mlog_errno(-ENOMEM);
1517                 goto leave;
1518         }
1519
1520         dlm->name = kmalloc(strlen(domain) + 1, GFP_KERNEL);
1521         if (dlm->name == NULL) {
1522                 mlog_errno(-ENOMEM);
1523                 kfree(dlm);
1524                 dlm = NULL;
1525                 goto leave;
1526         }
1527
1528         dlm->lockres_hash = (struct hlist_head **)dlm_alloc_pagevec(DLM_HASH_PAGES);
1529         if (!dlm->lockres_hash) {
1530                 mlog_errno(-ENOMEM);
1531                 kfree(dlm->name);
1532                 kfree(dlm);
1533                 dlm = NULL;
1534                 goto leave;
1535         }
1536
1537         for (i = 0; i < DLM_HASH_BUCKETS; i++)
1538                 INIT_HLIST_HEAD(dlm_lockres_hash(dlm, i));
1539
1540         dlm->master_hash = (struct hlist_head **)
1541                                 dlm_alloc_pagevec(DLM_HASH_PAGES);
1542         if (!dlm->master_hash) {
1543                 mlog_errno(-ENOMEM);
1544                 dlm_free_pagevec((void **)dlm->lockres_hash, DLM_HASH_PAGES);
1545                 kfree(dlm->name);
1546                 kfree(dlm);
1547                 dlm = NULL;
1548                 goto leave;
1549         }
1550
1551         for (i = 0; i < DLM_HASH_BUCKETS; i++)
1552                 INIT_HLIST_HEAD(dlm_master_hash(dlm, i));
1553
1554         strcpy(dlm->name, domain);
1555         dlm->key = key;
1556         dlm->node_num = o2nm_this_node();
1557
1558         ret = dlm_create_debugfs_subroot(dlm);
1559         if (ret < 0) {
1560                 dlm_free_pagevec((void **)dlm->master_hash, DLM_HASH_PAGES);
1561                 dlm_free_pagevec((void **)dlm->lockres_hash, DLM_HASH_PAGES);
1562                 kfree(dlm->name);
1563                 kfree(dlm);
1564                 dlm = NULL;
1565                 goto leave;
1566         }
1567
1568         spin_lock_init(&dlm->spinlock);
1569         spin_lock_init(&dlm->master_lock);
1570         spin_lock_init(&dlm->ast_lock);
1571         spin_lock_init(&dlm->track_lock);
1572         INIT_LIST_HEAD(&dlm->list);
1573         INIT_LIST_HEAD(&dlm->dirty_list);
1574         INIT_LIST_HEAD(&dlm->reco.resources);
1575         INIT_LIST_HEAD(&dlm->reco.received);
1576         INIT_LIST_HEAD(&dlm->reco.node_data);
1577         INIT_LIST_HEAD(&dlm->purge_list);
1578         INIT_LIST_HEAD(&dlm->dlm_domain_handlers);
1579         INIT_LIST_HEAD(&dlm->tracking_list);
1580         dlm->reco.state = 0;
1581
1582         INIT_LIST_HEAD(&dlm->pending_asts);
1583         INIT_LIST_HEAD(&dlm->pending_basts);
1584
1585         mlog(0, "dlm->recovery_map=%p, &(dlm->recovery_map[0])=%p\n",
1586                   dlm->recovery_map, &(dlm->recovery_map[0]));
1587
1588         memset(dlm->recovery_map, 0, sizeof(dlm->recovery_map));
1589         memset(dlm->live_nodes_map, 0, sizeof(dlm->live_nodes_map));
1590         memset(dlm->domain_map, 0, sizeof(dlm->domain_map));
1591
1592         dlm->dlm_thread_task = NULL;
1593         dlm->dlm_reco_thread_task = NULL;
1594         dlm->dlm_worker = NULL;
1595         init_waitqueue_head(&dlm->dlm_thread_wq);
1596         init_waitqueue_head(&dlm->dlm_reco_thread_wq);
1597         init_waitqueue_head(&dlm->reco.event);
1598         init_waitqueue_head(&dlm->ast_wq);
1599         init_waitqueue_head(&dlm->migration_wq);
1600         INIT_LIST_HEAD(&dlm->mle_hb_events);
1601
1602         dlm->joining_node = DLM_LOCK_RES_OWNER_UNKNOWN;
1603         init_waitqueue_head(&dlm->dlm_join_events);
1604
1605         dlm->reco.new_master = O2NM_INVALID_NODE_NUM;
1606         dlm->reco.dead_node = O2NM_INVALID_NODE_NUM;
1607
1608         atomic_set(&dlm->res_tot_count, 0);
1609         atomic_set(&dlm->res_cur_count, 0);
1610         for (i = 0; i < DLM_MLE_NUM_TYPES; ++i) {
1611                 atomic_set(&dlm->mle_tot_count[i], 0);
1612                 atomic_set(&dlm->mle_cur_count[i], 0);
1613         }
1614
1615         spin_lock_init(&dlm->work_lock);
1616         INIT_LIST_HEAD(&dlm->work_list);
1617         INIT_WORK(&dlm->dispatched_work, dlm_dispatch_work);
1618
1619         kref_init(&dlm->dlm_refs);
1620         dlm->dlm_state = DLM_CTXT_NEW;
1621
1622         INIT_LIST_HEAD(&dlm->dlm_eviction_callbacks);
1623
1624         mlog(0, "context init: refcount %u\n",
1625                   atomic_read(&dlm->dlm_refs.refcount));
1626
1627 leave:
1628         return dlm;
1629 }
1630
1631 /*
1632  * Compare a requested locking protocol version against the current one.
1633  *
1634  * If the major numbers are different, they are incompatible.
1635  * If the current minor is greater than the request, they are incompatible.
1636  * If the current minor is less than or equal to the request, they are
1637  * compatible, and the requester should run at the current minor version.
1638  */
1639 static int dlm_protocol_compare(struct dlm_protocol_version *existing,
1640                                 struct dlm_protocol_version *request)
1641 {
1642         if (existing->pv_major != request->pv_major)
1643                 return 1;
1644
1645         if (existing->pv_minor > request->pv_minor)
1646                 return 1;
1647
1648         if (existing->pv_minor < request->pv_minor)
1649                 request->pv_minor = existing->pv_minor;
1650
1651         return 0;
1652 }
1653
1654 /*
1655  * dlm_register_domain: one-time setup per "domain".
1656  *
1657  * The filesystem passes in the requested locking version via proto.
1658  * If registration was successful, proto will contain the negotiated
1659  * locking protocol.
1660  */
1661 struct dlm_ctxt * dlm_register_domain(const char *domain,
1662                                u32 key,
1663                                struct dlm_protocol_version *fs_proto)
1664 {
1665         int ret;
1666         struct dlm_ctxt *dlm = NULL;
1667         struct dlm_ctxt *new_ctxt = NULL;
1668
1669         if (strlen(domain) > O2NM_MAX_NAME_LEN) {
1670                 ret = -ENAMETOOLONG;
1671                 mlog(ML_ERROR, "domain name length too long\n");
1672                 goto leave;
1673         }
1674
1675         if (!o2hb_check_local_node_heartbeating()) {
1676                 mlog(ML_ERROR, "the local node has not been configured, or is "
1677                      "not heartbeating\n");
1678                 ret = -EPROTO;
1679                 goto leave;
1680         }
1681
1682         mlog(0, "register called for domain \"%s\"\n", domain);
1683
1684 retry:
1685         dlm = NULL;
1686         if (signal_pending(current)) {
1687                 ret = -ERESTARTSYS;
1688                 mlog_errno(ret);
1689                 goto leave;
1690         }
1691
1692         spin_lock(&dlm_domain_lock);
1693
1694         dlm = __dlm_lookup_domain(domain);
1695         if (dlm) {
1696                 if (dlm->dlm_state != DLM_CTXT_JOINED) {
1697                         spin_unlock(&dlm_domain_lock);
1698
1699                         mlog(0, "This ctxt is not joined yet!\n");
1700                         wait_event_interruptible(dlm_domain_events,
1701                                                  dlm_wait_on_domain_helper(
1702                                                          domain));
1703                         goto retry;
1704                 }
1705
1706                 if (dlm_protocol_compare(&dlm->fs_locking_proto, fs_proto)) {
1707                         mlog(ML_ERROR,
1708                              "Requested locking protocol version is not "
1709                              "compatible with already registered domain "
1710                              "\"%s\"\n", domain);
1711                         ret = -EPROTO;
1712                         goto leave;
1713                 }
1714
1715                 __dlm_get(dlm);
1716                 dlm->num_joins++;
1717
1718                 spin_unlock(&dlm_domain_lock);
1719
1720                 ret = 0;
1721                 goto leave;
1722         }
1723
1724         /* doesn't exist */
1725         if (!new_ctxt) {
1726                 spin_unlock(&dlm_domain_lock);
1727
1728                 new_ctxt = dlm_alloc_ctxt(domain, key);
1729                 if (new_ctxt)
1730                         goto retry;
1731
1732                 ret = -ENOMEM;
1733                 mlog_errno(ret);
1734                 goto leave;
1735         }
1736
1737         /* a little variable switch-a-roo here... */
1738         dlm = new_ctxt;
1739         new_ctxt = NULL;
1740
1741         /* add the new domain */
1742         list_add_tail(&dlm->list, &dlm_domains);
1743         spin_unlock(&dlm_domain_lock);
1744
1745         /*
1746          * Pass the locking protocol version into the join.  If the join
1747          * succeeds, it will have the negotiated protocol set.
1748          */
1749         dlm->dlm_locking_proto = dlm_protocol;
1750         dlm->fs_locking_proto = *fs_proto;
1751
1752         ret = dlm_join_domain(dlm);
1753         if (ret) {
1754                 mlog_errno(ret);
1755                 dlm_put(dlm);
1756                 goto leave;
1757         }
1758
1759         /* Tell the caller what locking protocol we negotiated */
1760         *fs_proto = dlm->fs_locking_proto;
1761
1762         ret = 0;
1763 leave:
1764         if (new_ctxt)
1765                 dlm_free_ctxt_mem(new_ctxt);
1766
1767         if (ret < 0)
1768                 dlm = ERR_PTR(ret);
1769
1770         return dlm;
1771 }
1772 EXPORT_SYMBOL_GPL(dlm_register_domain);
1773
1774 static LIST_HEAD(dlm_join_handlers);
1775
1776 static void dlm_unregister_net_handlers(void)
1777 {
1778         o2net_unregister_handler_list(&dlm_join_handlers);
1779 }
1780
1781 static int dlm_register_net_handlers(void)
1782 {
1783         int status = 0;
1784
1785         status = o2net_register_handler(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY,
1786                                         sizeof(struct dlm_query_join_request),
1787                                         dlm_query_join_handler,
1788                                         NULL, NULL, &dlm_join_handlers);
1789         if (status)
1790                 goto bail;
1791
1792         status = o2net_register_handler(DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
1793                                         sizeof(struct dlm_assert_joined),
1794                                         dlm_assert_joined_handler,
1795                                         NULL, NULL, &dlm_join_handlers);
1796         if (status)
1797                 goto bail;
1798
1799         status = o2net_register_handler(DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
1800                                         sizeof(struct dlm_cancel_join),
1801                                         dlm_cancel_join_handler,
1802                                         NULL, NULL, &dlm_join_handlers);
1803
1804 bail:
1805         if (status < 0)
1806                 dlm_unregister_net_handlers();
1807
1808         return status;
1809 }
1810
1811 /* Domain eviction callback handling.
1812  *
1813  * The file system requires notification of node death *before* the
1814  * dlm completes it's recovery work, otherwise it may be able to
1815  * acquire locks on resources requiring recovery. Since the dlm can
1816  * evict a node from it's domain *before* heartbeat fires, a similar
1817  * mechanism is required. */
1818
1819 /* Eviction is not expected to happen often, so a per-domain lock is
1820  * not necessary. Eviction callbacks are allowed to sleep for short
1821  * periods of time. */
1822 static DECLARE_RWSEM(dlm_callback_sem);
1823
1824 void dlm_fire_domain_eviction_callbacks(struct dlm_ctxt *dlm,
1825                                         int node_num)
1826 {
1827         struct list_head *iter;
1828         struct dlm_eviction_cb *cb;
1829
1830         down_read(&dlm_callback_sem);
1831         list_for_each(iter, &dlm->dlm_eviction_callbacks) {
1832                 cb = list_entry(iter, struct dlm_eviction_cb, ec_item);
1833
1834                 cb->ec_func(node_num, cb->ec_data);
1835         }
1836         up_read(&dlm_callback_sem);
1837 }
1838
1839 void dlm_setup_eviction_cb(struct dlm_eviction_cb *cb,
1840                            dlm_eviction_func *f,
1841                            void *data)
1842 {
1843         INIT_LIST_HEAD(&cb->ec_item);
1844         cb->ec_func = f;
1845         cb->ec_data = data;
1846 }
1847 EXPORT_SYMBOL_GPL(dlm_setup_eviction_cb);
1848
1849 void dlm_register_eviction_cb(struct dlm_ctxt *dlm,
1850                               struct dlm_eviction_cb *cb)
1851 {
1852         down_write(&dlm_callback_sem);
1853         list_add_tail(&cb->ec_item, &dlm->dlm_eviction_callbacks);
1854         up_write(&dlm_callback_sem);
1855 }
1856 EXPORT_SYMBOL_GPL(dlm_register_eviction_cb);
1857
1858 void dlm_unregister_eviction_cb(struct dlm_eviction_cb *cb)
1859 {
1860         down_write(&dlm_callback_sem);
1861         list_del_init(&cb->ec_item);
1862         up_write(&dlm_callback_sem);
1863 }
1864 EXPORT_SYMBOL_GPL(dlm_unregister_eviction_cb);
1865
1866 static int __init dlm_init(void)
1867 {
1868         int status;
1869
1870         dlm_print_version();
1871
1872         status = dlm_init_mle_cache();
1873         if (status) {
1874                 mlog(ML_ERROR, "Could not create o2dlm_mle slabcache\n");
1875                 goto error;
1876         }
1877
1878         status = dlm_init_master_caches();
1879         if (status) {
1880                 mlog(ML_ERROR, "Could not create o2dlm_lockres and "
1881                      "o2dlm_lockname slabcaches\n");
1882                 goto error;
1883         }
1884
1885         status = dlm_init_lock_cache();
1886         if (status) {
1887                 mlog(ML_ERROR, "Count not create o2dlm_lock slabcache\n");
1888                 goto error;
1889         }
1890
1891         status = dlm_register_net_handlers();
1892         if (status) {
1893                 mlog(ML_ERROR, "Unable to register network handlers\n");
1894                 goto error;
1895         }
1896
1897         status = dlm_create_debugfs_root();
1898         if (status)
1899                 goto error;
1900
1901         return 0;
1902 error:
1903         dlm_unregister_net_handlers();
1904         dlm_destroy_lock_cache();
1905         dlm_destroy_master_caches();
1906         dlm_destroy_mle_cache();
1907         return -1;
1908 }
1909
1910 static void __exit dlm_exit (void)
1911 {
1912         dlm_destroy_debugfs_root();
1913         dlm_unregister_net_handlers();
1914         dlm_destroy_lock_cache();
1915         dlm_destroy_master_caches();
1916         dlm_destroy_mle_cache();
1917 }
1918
1919 MODULE_AUTHOR("Oracle");
1920 MODULE_LICENSE("GPL");
1921
1922 module_init(dlm_init);
1923 module_exit(dlm_exit);