ocfs2/dlm: Fix race in adding/removing lockres' to/from the tracking list
[linux-2.6.git] / fs / ocfs2 / dlm / dlmdomain.c
1 /* -*- mode: c; c-basic-offset: 8; -*-
2  * vim: noexpandtab sw=8 ts=8 sts=0:
3  *
4  * dlmdomain.c
5  *
6  * defines domain join / leave apis
7  *
8  * Copyright (C) 2004 Oracle.  All rights reserved.
9  *
10  * This program is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU General Public
12  * License as published by the Free Software Foundation; either
13  * version 2 of the License, or (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18  * General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public
21  * License along with this program; if not, write to the
22  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
23  * Boston, MA 021110-1307, USA.
24  *
25  */
26
27 #include <linux/module.h>
28 #include <linux/types.h>
29 #include <linux/slab.h>
30 #include <linux/highmem.h>
31 #include <linux/utsname.h>
32 #include <linux/init.h>
33 #include <linux/spinlock.h>
34 #include <linux/delay.h>
35 #include <linux/err.h>
36 #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->name)
308                 kfree(dlm->name);
309
310         kfree(dlm);
311 }
312
313 /* A little strange - this function will be called while holding
314  * dlm_domain_lock and is expected to be holding it on the way out. We
315  * will however drop and reacquire it multiple times */
316 static void dlm_ctxt_release(struct kref *kref)
317 {
318         struct dlm_ctxt *dlm;
319
320         dlm = container_of(kref, struct dlm_ctxt, dlm_refs);
321
322         BUG_ON(dlm->num_joins);
323         BUG_ON(dlm->dlm_state == DLM_CTXT_JOINED);
324
325         /* we may still be in the list if we hit an error during join. */
326         list_del_init(&dlm->list);
327
328         spin_unlock(&dlm_domain_lock);
329
330         mlog(0, "freeing memory from domain %s\n", dlm->name);
331
332         wake_up(&dlm_domain_events);
333
334         dlm_free_ctxt_mem(dlm);
335
336         spin_lock(&dlm_domain_lock);
337 }
338
339 void dlm_put(struct dlm_ctxt *dlm)
340 {
341         spin_lock(&dlm_domain_lock);
342         kref_put(&dlm->dlm_refs, dlm_ctxt_release);
343         spin_unlock(&dlm_domain_lock);
344 }
345
346 static void __dlm_get(struct dlm_ctxt *dlm)
347 {
348         kref_get(&dlm->dlm_refs);
349 }
350
351 /* given a questionable reference to a dlm object, gets a reference if
352  * it can find it in the list, otherwise returns NULL in which case
353  * you shouldn't trust your pointer. */
354 struct dlm_ctxt *dlm_grab(struct dlm_ctxt *dlm)
355 {
356         struct list_head *iter;
357         struct dlm_ctxt *target = NULL;
358
359         spin_lock(&dlm_domain_lock);
360
361         list_for_each(iter, &dlm_domains) {
362                 target = list_entry (iter, struct dlm_ctxt, list);
363
364                 if (target == dlm) {
365                         __dlm_get(target);
366                         break;
367                 }
368
369                 target = NULL;
370         }
371
372         spin_unlock(&dlm_domain_lock);
373
374         return target;
375 }
376
377 int dlm_domain_fully_joined(struct dlm_ctxt *dlm)
378 {
379         int ret;
380
381         spin_lock(&dlm_domain_lock);
382         ret = (dlm->dlm_state == DLM_CTXT_JOINED) ||
383                 (dlm->dlm_state == DLM_CTXT_IN_SHUTDOWN);
384         spin_unlock(&dlm_domain_lock);
385
386         return ret;
387 }
388
389 static void dlm_destroy_dlm_worker(struct dlm_ctxt *dlm)
390 {
391         if (dlm->dlm_worker) {
392                 flush_workqueue(dlm->dlm_worker);
393                 destroy_workqueue(dlm->dlm_worker);
394                 dlm->dlm_worker = NULL;
395         }
396 }
397
398 static void dlm_complete_dlm_shutdown(struct dlm_ctxt *dlm)
399 {
400         dlm_unregister_domain_handlers(dlm);
401         dlm_debug_shutdown(dlm);
402         dlm_complete_thread(dlm);
403         dlm_complete_recovery_thread(dlm);
404         dlm_destroy_dlm_worker(dlm);
405
406         /* We've left the domain. Now we can take ourselves out of the
407          * list and allow the kref stuff to help us free the
408          * memory. */
409         spin_lock(&dlm_domain_lock);
410         list_del_init(&dlm->list);
411         spin_unlock(&dlm_domain_lock);
412
413         /* Wake up anyone waiting for us to remove this domain */
414         wake_up(&dlm_domain_events);
415 }
416
417 static int dlm_migrate_all_locks(struct dlm_ctxt *dlm)
418 {
419         int i, num, n, ret = 0;
420         struct dlm_lock_resource *res;
421         struct hlist_node *iter;
422         struct hlist_head *bucket;
423         int dropped;
424
425         mlog(0, "Migrating locks from domain %s\n", dlm->name);
426
427         num = 0;
428         spin_lock(&dlm->spinlock);
429         for (i = 0; i < DLM_HASH_BUCKETS; i++) {
430 redo_bucket:
431                 n = 0;
432                 bucket = dlm_lockres_hash(dlm, i);
433                 iter = bucket->first;
434                 while (iter) {
435                         n++;
436                         res = hlist_entry(iter, struct dlm_lock_resource,
437                                           hash_node);
438                         dlm_lockres_get(res);
439                         /* migrate, if necessary.  this will drop the dlm
440                          * spinlock and retake it if it does migration. */
441                         dropped = dlm_empty_lockres(dlm, res);
442
443                         spin_lock(&res->spinlock);
444                         __dlm_lockres_calc_usage(dlm, res);
445                         iter = res->hash_node.next;
446                         spin_unlock(&res->spinlock);
447
448                         dlm_lockres_put(res);
449
450                         if (dropped)
451                                 goto redo_bucket;
452                 }
453                 cond_resched_lock(&dlm->spinlock);
454                 num += n;
455                 mlog(0, "%s: touched %d lockreses in bucket %d "
456                      "(tot=%d)\n", dlm->name, n, i, num);
457         }
458         spin_unlock(&dlm->spinlock);
459         wake_up(&dlm->dlm_thread_wq);
460
461         /* let the dlm thread take care of purging, keep scanning until
462          * nothing remains in the hash */
463         if (num) {
464                 mlog(0, "%s: %d lock resources in hash last pass\n",
465                      dlm->name, num);
466                 ret = -EAGAIN;
467         }
468         mlog(0, "DONE Migrating locks from domain %s\n", dlm->name);
469         return ret;
470 }
471
472 static int dlm_no_joining_node(struct dlm_ctxt *dlm)
473 {
474         int ret;
475
476         spin_lock(&dlm->spinlock);
477         ret = dlm->joining_node == DLM_LOCK_RES_OWNER_UNKNOWN;
478         spin_unlock(&dlm->spinlock);
479
480         return ret;
481 }
482
483 static void dlm_mark_domain_leaving(struct dlm_ctxt *dlm)
484 {
485         /* Yikes, a double spinlock! I need domain_lock for the dlm
486          * state and the dlm spinlock for join state... Sorry! */
487 again:
488         spin_lock(&dlm_domain_lock);
489         spin_lock(&dlm->spinlock);
490
491         if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
492                 mlog(0, "Node %d is joining, we wait on it.\n",
493                           dlm->joining_node);
494                 spin_unlock(&dlm->spinlock);
495                 spin_unlock(&dlm_domain_lock);
496
497                 wait_event(dlm->dlm_join_events, dlm_no_joining_node(dlm));
498                 goto again;
499         }
500
501         dlm->dlm_state = DLM_CTXT_LEAVING;
502         spin_unlock(&dlm->spinlock);
503         spin_unlock(&dlm_domain_lock);
504 }
505
506 static void __dlm_print_nodes(struct dlm_ctxt *dlm)
507 {
508         int node = -1;
509
510         assert_spin_locked(&dlm->spinlock);
511
512         printk(KERN_INFO "ocfs2_dlm: Nodes in domain (\"%s\"): ", dlm->name);
513
514         while ((node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES,
515                                      node + 1)) < O2NM_MAX_NODES) {
516                 printk("%d ", node);
517         }
518         printk("\n");
519 }
520
521 static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data,
522                                    void **ret_data)
523 {
524         struct dlm_ctxt *dlm = data;
525         unsigned int node;
526         struct dlm_exit_domain *exit_msg = (struct dlm_exit_domain *) msg->buf;
527
528         mlog_entry("%p %u %p", msg, len, data);
529
530         if (!dlm_grab(dlm))
531                 return 0;
532
533         node = exit_msg->node_idx;
534
535         printk(KERN_INFO "ocfs2_dlm: Node %u leaves domain %s\n", node, dlm->name);
536
537         spin_lock(&dlm->spinlock);
538         clear_bit(node, dlm->domain_map);
539         __dlm_print_nodes(dlm);
540
541         /* notify anything attached to the heartbeat events */
542         dlm_hb_event_notify_attached(dlm, node, 0);
543
544         spin_unlock(&dlm->spinlock);
545
546         dlm_put(dlm);
547
548         return 0;
549 }
550
551 static int dlm_send_one_domain_exit(struct dlm_ctxt *dlm,
552                                     unsigned int node)
553 {
554         int status;
555         struct dlm_exit_domain leave_msg;
556
557         mlog(0, "Asking node %u if we can leave the domain %s me = %u\n",
558                   node, dlm->name, dlm->node_num);
559
560         memset(&leave_msg, 0, sizeof(leave_msg));
561         leave_msg.node_idx = dlm->node_num;
562
563         status = o2net_send_message(DLM_EXIT_DOMAIN_MSG, dlm->key,
564                                     &leave_msg, sizeof(leave_msg), node,
565                                     NULL);
566
567         mlog(0, "status return %d from o2net_send_message\n", status);
568
569         return status;
570 }
571
572
573 static void dlm_leave_domain(struct dlm_ctxt *dlm)
574 {
575         int node, clear_node, status;
576
577         /* At this point we've migrated away all our locks and won't
578          * accept mastership of new ones. The dlm is responsible for
579          * almost nothing now. We make sure not to confuse any joining
580          * nodes and then commence shutdown procedure. */
581
582         spin_lock(&dlm->spinlock);
583         /* Clear ourselves from the domain map */
584         clear_bit(dlm->node_num, dlm->domain_map);
585         while ((node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES,
586                                      0)) < O2NM_MAX_NODES) {
587                 /* Drop the dlm spinlock. This is safe wrt the domain_map.
588                  * -nodes cannot be added now as the
589                  *   query_join_handlers knows to respond with OK_NO_MAP
590                  * -we catch the right network errors if a node is
591                  *   removed from the map while we're sending him the
592                  *   exit message. */
593                 spin_unlock(&dlm->spinlock);
594
595                 clear_node = 1;
596
597                 status = dlm_send_one_domain_exit(dlm, node);
598                 if (status < 0 &&
599                     status != -ENOPROTOOPT &&
600                     status != -ENOTCONN) {
601                         mlog(ML_NOTICE, "Error %d sending domain exit message "
602                              "to node %d\n", status, node);
603
604                         /* Not sure what to do here but lets sleep for
605                          * a bit in case this was a transient
606                          * error... */
607                         msleep(DLM_DOMAIN_BACKOFF_MS);
608                         clear_node = 0;
609                 }
610
611                 spin_lock(&dlm->spinlock);
612                 /* If we're not clearing the node bit then we intend
613                  * to loop back around to try again. */
614                 if (clear_node)
615                         clear_bit(node, dlm->domain_map);
616         }
617         spin_unlock(&dlm->spinlock);
618 }
619
620 int dlm_joined(struct dlm_ctxt *dlm)
621 {
622         int ret = 0;
623
624         spin_lock(&dlm_domain_lock);
625
626         if (dlm->dlm_state == DLM_CTXT_JOINED)
627                 ret = 1;
628
629         spin_unlock(&dlm_domain_lock);
630
631         return ret;
632 }
633
634 int dlm_shutting_down(struct dlm_ctxt *dlm)
635 {
636         int ret = 0;
637
638         spin_lock(&dlm_domain_lock);
639
640         if (dlm->dlm_state == DLM_CTXT_IN_SHUTDOWN)
641                 ret = 1;
642
643         spin_unlock(&dlm_domain_lock);
644
645         return ret;
646 }
647
648 void dlm_unregister_domain(struct dlm_ctxt *dlm)
649 {
650         int leave = 0;
651         struct dlm_lock_resource *res;
652
653         spin_lock(&dlm_domain_lock);
654         BUG_ON(dlm->dlm_state != DLM_CTXT_JOINED);
655         BUG_ON(!dlm->num_joins);
656
657         dlm->num_joins--;
658         if (!dlm->num_joins) {
659                 /* We mark it "in shutdown" now so new register
660                  * requests wait until we've completely left the
661                  * domain. Don't use DLM_CTXT_LEAVING yet as we still
662                  * want new domain joins to communicate with us at
663                  * least until we've completed migration of our
664                  * resources. */
665                 dlm->dlm_state = DLM_CTXT_IN_SHUTDOWN;
666                 leave = 1;
667         }
668         spin_unlock(&dlm_domain_lock);
669
670         if (leave) {
671                 mlog(0, "shutting down domain %s\n", dlm->name);
672
673                 /* We changed dlm state, notify the thread */
674                 dlm_kick_thread(dlm, NULL);
675
676                 while (dlm_migrate_all_locks(dlm)) {
677                         /* Give dlm_thread time to purge the lockres' */
678                         msleep(500);
679                         mlog(0, "%s: more migration to do\n", dlm->name);
680                 }
681
682                 /* This list should be empty. If not, print remaining lockres */
683                 if (!list_empty(&dlm->tracking_list)) {
684                         mlog(ML_ERROR, "Following lockres' are still on the "
685                              "tracking list:\n");
686                         list_for_each_entry(res, &dlm->tracking_list, tracking)
687                                 dlm_print_one_lock_resource(res);
688                 }
689
690                 dlm_mark_domain_leaving(dlm);
691                 dlm_leave_domain(dlm);
692                 dlm_complete_dlm_shutdown(dlm);
693         }
694         dlm_put(dlm);
695 }
696 EXPORT_SYMBOL_GPL(dlm_unregister_domain);
697
698 static int dlm_query_join_proto_check(char *proto_type, int node,
699                                       struct dlm_protocol_version *ours,
700                                       struct dlm_protocol_version *request)
701 {
702         int rc;
703         struct dlm_protocol_version proto = *request;
704
705         if (!dlm_protocol_compare(ours, &proto)) {
706                 mlog(0,
707                      "node %u wanted to join with %s locking protocol "
708                      "%u.%u, we respond with %u.%u\n",
709                      node, proto_type,
710                      request->pv_major,
711                      request->pv_minor,
712                      proto.pv_major, proto.pv_minor);
713                 request->pv_minor = proto.pv_minor;
714                 rc = 0;
715         } else {
716                 mlog(ML_NOTICE,
717                      "Node %u wanted to join with %s locking "
718                      "protocol %u.%u, but we have %u.%u, disallowing\n",
719                      node, proto_type,
720                      request->pv_major,
721                      request->pv_minor,
722                      ours->pv_major,
723                      ours->pv_minor);
724                 rc = 1;
725         }
726
727         return rc;
728 }
729
730 /*
731  * struct dlm_query_join_packet is made up of four one-byte fields.  They
732  * are effectively in big-endian order already.  However, little-endian
733  * machines swap them before putting the packet on the wire (because
734  * query_join's response is a status, and that status is treated as a u32
735  * on the wire).  Thus, a big-endian and little-endian machines will treat
736  * this structure differently.
737  *
738  * The solution is to have little-endian machines swap the structure when
739  * converting from the structure to the u32 representation.  This will
740  * result in the structure having the correct format on the wire no matter
741  * the host endian format.
742  */
743 static void dlm_query_join_packet_to_wire(struct dlm_query_join_packet *packet,
744                                           u32 *wire)
745 {
746         union dlm_query_join_response response;
747
748         response.packet = *packet;
749         *wire = cpu_to_be32(response.intval);
750 }
751
752 static void dlm_query_join_wire_to_packet(u32 wire,
753                                           struct dlm_query_join_packet *packet)
754 {
755         union dlm_query_join_response response;
756
757         response.intval = cpu_to_be32(wire);
758         *packet = response.packet;
759 }
760
761 static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
762                                   void **ret_data)
763 {
764         struct dlm_query_join_request *query;
765         struct dlm_query_join_packet packet = {
766                 .code = JOIN_DISALLOW,
767         };
768         struct dlm_ctxt *dlm = NULL;
769         u32 response;
770         u8 nodenum;
771
772         query = (struct dlm_query_join_request *) msg->buf;
773
774         mlog(0, "node %u wants to join domain %s\n", query->node_idx,
775                   query->domain);
776
777         /*
778          * If heartbeat doesn't consider the node live, tell it
779          * to back off and try again.  This gives heartbeat a chance
780          * to catch up.
781          */
782         if (!o2hb_check_node_heartbeating(query->node_idx)) {
783                 mlog(0, "node %u is not in our live map yet\n",
784                      query->node_idx);
785
786                 packet.code = JOIN_DISALLOW;
787                 goto respond;
788         }
789
790         packet.code = JOIN_OK_NO_MAP;
791
792         spin_lock(&dlm_domain_lock);
793         dlm = __dlm_lookup_domain_full(query->domain, query->name_len);
794         if (!dlm)
795                 goto unlock_respond;
796
797         /*
798          * There is a small window where the joining node may not see the
799          * node(s) that just left but still part of the cluster. DISALLOW
800          * join request if joining node has different node map.
801          */
802         nodenum=0;
803         while (nodenum < O2NM_MAX_NODES) {
804                 if (test_bit(nodenum, dlm->domain_map)) {
805                         if (!byte_test_bit(nodenum, query->node_map)) {
806                                 mlog(0, "disallow join as node %u does not "
807                                      "have node %u in its nodemap\n",
808                                      query->node_idx, nodenum);
809                                 packet.code = JOIN_DISALLOW;
810                                 goto unlock_respond;
811                         }
812                 }
813                 nodenum++;
814         }
815
816         /* Once the dlm ctxt is marked as leaving then we don't want
817          * to be put in someone's domain map. 
818          * Also, explicitly disallow joining at certain troublesome
819          * times (ie. during recovery). */
820         if (dlm && dlm->dlm_state != DLM_CTXT_LEAVING) {
821                 int bit = query->node_idx;
822                 spin_lock(&dlm->spinlock);
823
824                 if (dlm->dlm_state == DLM_CTXT_NEW &&
825                     dlm->joining_node == DLM_LOCK_RES_OWNER_UNKNOWN) {
826                         /*If this is a brand new context and we
827                          * haven't started our join process yet, then
828                          * the other node won the race. */
829                         packet.code = JOIN_OK_NO_MAP;
830                 } else if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
831                         /* Disallow parallel joins. */
832                         packet.code = JOIN_DISALLOW;
833                 } else if (dlm->reco.state & DLM_RECO_STATE_ACTIVE) {
834                         mlog(0, "node %u trying to join, but recovery "
835                              "is ongoing.\n", bit);
836                         packet.code = JOIN_DISALLOW;
837                 } else if (test_bit(bit, dlm->recovery_map)) {
838                         mlog(0, "node %u trying to join, but it "
839                              "still needs recovery.\n", bit);
840                         packet.code = JOIN_DISALLOW;
841                 } else if (test_bit(bit, dlm->domain_map)) {
842                         mlog(0, "node %u trying to join, but it "
843                              "is still in the domain! needs recovery?\n",
844                              bit);
845                         packet.code = JOIN_DISALLOW;
846                 } else {
847                         /* Alright we're fully a part of this domain
848                          * so we keep some state as to who's joining
849                          * and indicate to him that needs to be fixed
850                          * up. */
851
852                         /* Make sure we speak compatible locking protocols.  */
853                         if (dlm_query_join_proto_check("DLM", bit,
854                                                        &dlm->dlm_locking_proto,
855                                                        &query->dlm_proto)) {
856                                 packet.code = JOIN_PROTOCOL_MISMATCH;
857                         } else if (dlm_query_join_proto_check("fs", bit,
858                                                               &dlm->fs_locking_proto,
859                                                               &query->fs_proto)) {
860                                 packet.code = JOIN_PROTOCOL_MISMATCH;
861                         } else {
862                                 packet.dlm_minor = query->dlm_proto.pv_minor;
863                                 packet.fs_minor = query->fs_proto.pv_minor;
864                                 packet.code = JOIN_OK;
865                                 __dlm_set_joining_node(dlm, query->node_idx);
866                         }
867                 }
868
869                 spin_unlock(&dlm->spinlock);
870         }
871 unlock_respond:
872         spin_unlock(&dlm_domain_lock);
873
874 respond:
875         mlog(0, "We respond with %u\n", packet.code);
876
877         dlm_query_join_packet_to_wire(&packet, &response);
878         return response;
879 }
880
881 static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data,
882                                      void **ret_data)
883 {
884         struct dlm_assert_joined *assert;
885         struct dlm_ctxt *dlm = NULL;
886
887         assert = (struct dlm_assert_joined *) msg->buf;
888
889         mlog(0, "node %u asserts join on domain %s\n", assert->node_idx,
890                   assert->domain);
891
892         spin_lock(&dlm_domain_lock);
893         dlm = __dlm_lookup_domain_full(assert->domain, assert->name_len);
894         /* XXX should we consider no dlm ctxt an error? */
895         if (dlm) {
896                 spin_lock(&dlm->spinlock);
897
898                 /* Alright, this node has officially joined our
899                  * domain. Set him in the map and clean up our
900                  * leftover join state. */
901                 BUG_ON(dlm->joining_node != assert->node_idx);
902                 set_bit(assert->node_idx, dlm->domain_map);
903                 __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
904
905                 printk(KERN_INFO "ocfs2_dlm: Node %u joins domain %s\n",
906                        assert->node_idx, dlm->name);
907                 __dlm_print_nodes(dlm);
908
909                 /* notify anything attached to the heartbeat events */
910                 dlm_hb_event_notify_attached(dlm, assert->node_idx, 1);
911
912                 spin_unlock(&dlm->spinlock);
913         }
914         spin_unlock(&dlm_domain_lock);
915
916         return 0;
917 }
918
919 static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data,
920                                    void **ret_data)
921 {
922         struct dlm_cancel_join *cancel;
923         struct dlm_ctxt *dlm = NULL;
924
925         cancel = (struct dlm_cancel_join *) msg->buf;
926
927         mlog(0, "node %u cancels join on domain %s\n", cancel->node_idx,
928                   cancel->domain);
929
930         spin_lock(&dlm_domain_lock);
931         dlm = __dlm_lookup_domain_full(cancel->domain, cancel->name_len);
932
933         if (dlm) {
934                 spin_lock(&dlm->spinlock);
935
936                 /* Yikes, this guy wants to cancel his join. No
937                  * problem, we simply cleanup our join state. */
938                 BUG_ON(dlm->joining_node != cancel->node_idx);
939                 __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
940
941                 spin_unlock(&dlm->spinlock);
942         }
943         spin_unlock(&dlm_domain_lock);
944
945         return 0;
946 }
947
948 static int dlm_send_one_join_cancel(struct dlm_ctxt *dlm,
949                                     unsigned int node)
950 {
951         int status;
952         struct dlm_cancel_join cancel_msg;
953
954         memset(&cancel_msg, 0, sizeof(cancel_msg));
955         cancel_msg.node_idx = dlm->node_num;
956         cancel_msg.name_len = strlen(dlm->name);
957         memcpy(cancel_msg.domain, dlm->name, cancel_msg.name_len);
958
959         status = o2net_send_message(DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
960                                     &cancel_msg, sizeof(cancel_msg), node,
961                                     NULL);
962         if (status < 0) {
963                 mlog_errno(status);
964                 goto bail;
965         }
966
967 bail:
968         return status;
969 }
970
971 /* map_size should be in bytes. */
972 static int dlm_send_join_cancels(struct dlm_ctxt *dlm,
973                                  unsigned long *node_map,
974                                  unsigned int map_size)
975 {
976         int status, tmpstat;
977         unsigned int node;
978
979         if (map_size != (BITS_TO_LONGS(O2NM_MAX_NODES) *
980                          sizeof(unsigned long))) {
981                 mlog(ML_ERROR,
982                      "map_size %u != BITS_TO_LONGS(O2NM_MAX_NODES) %u\n",
983                      map_size, (unsigned)BITS_TO_LONGS(O2NM_MAX_NODES));
984                 return -EINVAL;
985         }
986
987         status = 0;
988         node = -1;
989         while ((node = find_next_bit(node_map, O2NM_MAX_NODES,
990                                      node + 1)) < O2NM_MAX_NODES) {
991                 if (node == dlm->node_num)
992                         continue;
993
994                 tmpstat = dlm_send_one_join_cancel(dlm, node);
995                 if (tmpstat) {
996                         mlog(ML_ERROR, "Error return %d cancelling join on "
997                              "node %d\n", tmpstat, node);
998                         if (!status)
999                                 status = tmpstat;
1000                 }
1001         }
1002
1003         if (status)
1004                 mlog_errno(status);
1005         return status;
1006 }
1007
1008 static int dlm_request_join(struct dlm_ctxt *dlm,
1009                             int node,
1010                             enum dlm_query_join_response_code *response)
1011 {
1012         int status;
1013         struct dlm_query_join_request join_msg;
1014         struct dlm_query_join_packet packet;
1015         u32 join_resp;
1016
1017         mlog(0, "querying node %d\n", node);
1018
1019         memset(&join_msg, 0, sizeof(join_msg));
1020         join_msg.node_idx = dlm->node_num;
1021         join_msg.name_len = strlen(dlm->name);
1022         memcpy(join_msg.domain, dlm->name, join_msg.name_len);
1023         join_msg.dlm_proto = dlm->dlm_locking_proto;
1024         join_msg.fs_proto = dlm->fs_locking_proto;
1025
1026         /* copy live node map to join message */
1027         byte_copymap(join_msg.node_map, dlm->live_nodes_map, O2NM_MAX_NODES);
1028
1029         status = o2net_send_message(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY, &join_msg,
1030                                     sizeof(join_msg), node,
1031                                     &join_resp);
1032         if (status < 0 && status != -ENOPROTOOPT) {
1033                 mlog_errno(status);
1034                 goto bail;
1035         }
1036         dlm_query_join_wire_to_packet(join_resp, &packet);
1037
1038         /* -ENOPROTOOPT from the net code means the other side isn't
1039             listening for our message type -- that's fine, it means
1040             his dlm isn't up, so we can consider him a 'yes' but not
1041             joined into the domain.  */
1042         if (status == -ENOPROTOOPT) {
1043                 status = 0;
1044                 *response = JOIN_OK_NO_MAP;
1045         } else if (packet.code == JOIN_DISALLOW ||
1046                    packet.code == JOIN_OK_NO_MAP) {
1047                 *response = packet.code;
1048         } else if (packet.code == JOIN_PROTOCOL_MISMATCH) {
1049                 mlog(ML_NOTICE,
1050                      "This node requested DLM locking protocol %u.%u and "
1051                      "filesystem locking protocol %u.%u.  At least one of "
1052                      "the protocol versions on node %d is not compatible, "
1053                      "disconnecting\n",
1054                      dlm->dlm_locking_proto.pv_major,
1055                      dlm->dlm_locking_proto.pv_minor,
1056                      dlm->fs_locking_proto.pv_major,
1057                      dlm->fs_locking_proto.pv_minor,
1058                      node);
1059                 status = -EPROTO;
1060                 *response = packet.code;
1061         } else if (packet.code == JOIN_OK) {
1062                 *response = packet.code;
1063                 /* Use the same locking protocol as the remote node */
1064                 dlm->dlm_locking_proto.pv_minor = packet.dlm_minor;
1065                 dlm->fs_locking_proto.pv_minor = packet.fs_minor;
1066                 mlog(0,
1067                      "Node %d responds JOIN_OK with DLM locking protocol "
1068                      "%u.%u and fs locking protocol %u.%u\n",
1069                      node,
1070                      dlm->dlm_locking_proto.pv_major,
1071                      dlm->dlm_locking_proto.pv_minor,
1072                      dlm->fs_locking_proto.pv_major,
1073                      dlm->fs_locking_proto.pv_minor);
1074         } else {
1075                 status = -EINVAL;
1076                 mlog(ML_ERROR, "invalid response %d from node %u\n",
1077                      packet.code, node);
1078         }
1079
1080         mlog(0, "status %d, node %d response is %d\n", status, node,
1081              *response);
1082
1083 bail:
1084         return status;
1085 }
1086
1087 static int dlm_send_one_join_assert(struct dlm_ctxt *dlm,
1088                                     unsigned int node)
1089 {
1090         int status;
1091         struct dlm_assert_joined assert_msg;
1092
1093         mlog(0, "Sending join assert to node %u\n", node);
1094
1095         memset(&assert_msg, 0, sizeof(assert_msg));
1096         assert_msg.node_idx = dlm->node_num;
1097         assert_msg.name_len = strlen(dlm->name);
1098         memcpy(assert_msg.domain, dlm->name, assert_msg.name_len);
1099
1100         status = o2net_send_message(DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
1101                                     &assert_msg, sizeof(assert_msg), node,
1102                                     NULL);
1103         if (status < 0)
1104                 mlog_errno(status);
1105
1106         return status;
1107 }
1108
1109 static void dlm_send_join_asserts(struct dlm_ctxt *dlm,
1110                                   unsigned long *node_map)
1111 {
1112         int status, node, live;
1113
1114         status = 0;
1115         node = -1;
1116         while ((node = find_next_bit(node_map, O2NM_MAX_NODES,
1117                                      node + 1)) < O2NM_MAX_NODES) {
1118                 if (node == dlm->node_num)
1119                         continue;
1120
1121                 do {
1122                         /* It is very important that this message be
1123                          * received so we spin until either the node
1124                          * has died or it gets the message. */
1125                         status = dlm_send_one_join_assert(dlm, node);
1126
1127                         spin_lock(&dlm->spinlock);
1128                         live = test_bit(node, dlm->live_nodes_map);
1129                         spin_unlock(&dlm->spinlock);
1130
1131                         if (status) {
1132                                 mlog(ML_ERROR, "Error return %d asserting "
1133                                      "join on node %d\n", status, node);
1134
1135                                 /* give us some time between errors... */
1136                                 if (live)
1137                                         msleep(DLM_DOMAIN_BACKOFF_MS);
1138                         }
1139                 } while (status && live);
1140         }
1141 }
1142
1143 struct domain_join_ctxt {
1144         unsigned long live_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1145         unsigned long yes_resp_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1146 };
1147
1148 static int dlm_should_restart_join(struct dlm_ctxt *dlm,
1149                                    struct domain_join_ctxt *ctxt,
1150                                    enum dlm_query_join_response_code response)
1151 {
1152         int ret;
1153
1154         if (response == JOIN_DISALLOW) {
1155                 mlog(0, "Latest response of disallow -- should restart\n");
1156                 return 1;
1157         }
1158
1159         spin_lock(&dlm->spinlock);
1160         /* For now, we restart the process if the node maps have
1161          * changed at all */
1162         ret = memcmp(ctxt->live_map, dlm->live_nodes_map,
1163                      sizeof(dlm->live_nodes_map));
1164         spin_unlock(&dlm->spinlock);
1165
1166         if (ret)
1167                 mlog(0, "Node maps changed -- should restart\n");
1168
1169         return ret;
1170 }
1171
1172 static int dlm_try_to_join_domain(struct dlm_ctxt *dlm)
1173 {
1174         int status = 0, tmpstat, node;
1175         struct domain_join_ctxt *ctxt;
1176         enum dlm_query_join_response_code response = JOIN_DISALLOW;
1177
1178         mlog_entry("%p", dlm);
1179
1180         ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL);
1181         if (!ctxt) {
1182                 status = -ENOMEM;
1183                 mlog_errno(status);
1184                 goto bail;
1185         }
1186
1187         /* group sem locking should work for us here -- we're already
1188          * registered for heartbeat events so filling this should be
1189          * atomic wrt getting those handlers called. */
1190         o2hb_fill_node_map(dlm->live_nodes_map, sizeof(dlm->live_nodes_map));
1191
1192         spin_lock(&dlm->spinlock);
1193         memcpy(ctxt->live_map, dlm->live_nodes_map, sizeof(ctxt->live_map));
1194
1195         __dlm_set_joining_node(dlm, dlm->node_num);
1196
1197         spin_unlock(&dlm->spinlock);
1198
1199         node = -1;
1200         while ((node = find_next_bit(ctxt->live_map, O2NM_MAX_NODES,
1201                                      node + 1)) < O2NM_MAX_NODES) {
1202                 if (node == dlm->node_num)
1203                         continue;
1204
1205                 status = dlm_request_join(dlm, node, &response);
1206                 if (status < 0) {
1207                         mlog_errno(status);
1208                         goto bail;
1209                 }
1210
1211                 /* Ok, either we got a response or the node doesn't have a
1212                  * dlm up. */
1213                 if (response == JOIN_OK)
1214                         set_bit(node, ctxt->yes_resp_map);
1215
1216                 if (dlm_should_restart_join(dlm, ctxt, response)) {
1217                         status = -EAGAIN;
1218                         goto bail;
1219                 }
1220         }
1221
1222         mlog(0, "Yay, done querying nodes!\n");
1223
1224         /* Yay, everyone agree's we can join the domain. My domain is
1225          * comprised of all nodes who were put in the
1226          * yes_resp_map. Copy that into our domain map and send a join
1227          * assert message to clean up everyone elses state. */
1228         spin_lock(&dlm->spinlock);
1229         memcpy(dlm->domain_map, ctxt->yes_resp_map,
1230                sizeof(ctxt->yes_resp_map));
1231         set_bit(dlm->node_num, dlm->domain_map);
1232         spin_unlock(&dlm->spinlock);
1233
1234         dlm_send_join_asserts(dlm, ctxt->yes_resp_map);
1235
1236         /* Joined state *must* be set before the joining node
1237          * information, otherwise the query_join handler may read no
1238          * current joiner but a state of NEW and tell joining nodes
1239          * we're not in the domain. */
1240         spin_lock(&dlm_domain_lock);
1241         dlm->dlm_state = DLM_CTXT_JOINED;
1242         dlm->num_joins++;
1243         spin_unlock(&dlm_domain_lock);
1244
1245 bail:
1246         spin_lock(&dlm->spinlock);
1247         __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
1248         if (!status)
1249                 __dlm_print_nodes(dlm);
1250         spin_unlock(&dlm->spinlock);
1251
1252         if (ctxt) {
1253                 /* Do we need to send a cancel message to any nodes? */
1254                 if (status < 0) {
1255                         tmpstat = dlm_send_join_cancels(dlm,
1256                                                         ctxt->yes_resp_map,
1257                                                         sizeof(ctxt->yes_resp_map));
1258                         if (tmpstat < 0)
1259                                 mlog_errno(tmpstat);
1260                 }
1261                 kfree(ctxt);
1262         }
1263
1264         mlog(0, "returning %d\n", status);
1265         return status;
1266 }
1267
1268 static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm)
1269 {
1270         o2hb_unregister_callback(NULL, &dlm->dlm_hb_up);
1271         o2hb_unregister_callback(NULL, &dlm->dlm_hb_down);
1272         o2net_unregister_handler_list(&dlm->dlm_domain_handlers);
1273 }
1274
1275 static int dlm_register_domain_handlers(struct dlm_ctxt *dlm)
1276 {
1277         int status;
1278
1279         mlog(0, "registering handlers.\n");
1280
1281         o2hb_setup_callback(&dlm->dlm_hb_down, O2HB_NODE_DOWN_CB,
1282                             dlm_hb_node_down_cb, dlm, DLM_HB_NODE_DOWN_PRI);
1283         status = o2hb_register_callback(NULL, &dlm->dlm_hb_down);
1284         if (status)
1285                 goto bail;
1286
1287         o2hb_setup_callback(&dlm->dlm_hb_up, O2HB_NODE_UP_CB,
1288                             dlm_hb_node_up_cb, dlm, DLM_HB_NODE_UP_PRI);
1289         status = o2hb_register_callback(NULL, &dlm->dlm_hb_up);
1290         if (status)
1291                 goto bail;
1292
1293         status = o2net_register_handler(DLM_MASTER_REQUEST_MSG, dlm->key,
1294                                         sizeof(struct dlm_master_request),
1295                                         dlm_master_request_handler,
1296                                         dlm, NULL, &dlm->dlm_domain_handlers);
1297         if (status)
1298                 goto bail;
1299
1300         status = o2net_register_handler(DLM_ASSERT_MASTER_MSG, dlm->key,
1301                                         sizeof(struct dlm_assert_master),
1302                                         dlm_assert_master_handler,
1303                                         dlm, dlm_assert_master_post_handler,
1304                                         &dlm->dlm_domain_handlers);
1305         if (status)
1306                 goto bail;
1307
1308         status = o2net_register_handler(DLM_CREATE_LOCK_MSG, dlm->key,
1309                                         sizeof(struct dlm_create_lock),
1310                                         dlm_create_lock_handler,
1311                                         dlm, NULL, &dlm->dlm_domain_handlers);
1312         if (status)
1313                 goto bail;
1314
1315         status = o2net_register_handler(DLM_CONVERT_LOCK_MSG, dlm->key,
1316                                         DLM_CONVERT_LOCK_MAX_LEN,
1317                                         dlm_convert_lock_handler,
1318                                         dlm, NULL, &dlm->dlm_domain_handlers);
1319         if (status)
1320                 goto bail;
1321
1322         status = o2net_register_handler(DLM_UNLOCK_LOCK_MSG, dlm->key,
1323                                         DLM_UNLOCK_LOCK_MAX_LEN,
1324                                         dlm_unlock_lock_handler,
1325                                         dlm, NULL, &dlm->dlm_domain_handlers);
1326         if (status)
1327                 goto bail;
1328
1329         status = o2net_register_handler(DLM_PROXY_AST_MSG, dlm->key,
1330                                         DLM_PROXY_AST_MAX_LEN,
1331                                         dlm_proxy_ast_handler,
1332                                         dlm, NULL, &dlm->dlm_domain_handlers);
1333         if (status)
1334                 goto bail;
1335
1336         status = o2net_register_handler(DLM_EXIT_DOMAIN_MSG, dlm->key,
1337                                         sizeof(struct dlm_exit_domain),
1338                                         dlm_exit_domain_handler,
1339                                         dlm, NULL, &dlm->dlm_domain_handlers);
1340         if (status)
1341                 goto bail;
1342
1343         status = o2net_register_handler(DLM_DEREF_LOCKRES_MSG, dlm->key,
1344                                         sizeof(struct dlm_deref_lockres),
1345                                         dlm_deref_lockres_handler,
1346                                         dlm, NULL, &dlm->dlm_domain_handlers);
1347         if (status)
1348                 goto bail;
1349
1350         status = o2net_register_handler(DLM_MIGRATE_REQUEST_MSG, dlm->key,
1351                                         sizeof(struct dlm_migrate_request),
1352                                         dlm_migrate_request_handler,
1353                                         dlm, NULL, &dlm->dlm_domain_handlers);
1354         if (status)
1355                 goto bail;
1356
1357         status = o2net_register_handler(DLM_MIG_LOCKRES_MSG, dlm->key,
1358                                         DLM_MIG_LOCKRES_MAX_LEN,
1359                                         dlm_mig_lockres_handler,
1360                                         dlm, NULL, &dlm->dlm_domain_handlers);
1361         if (status)
1362                 goto bail;
1363
1364         status = o2net_register_handler(DLM_MASTER_REQUERY_MSG, dlm->key,
1365                                         sizeof(struct dlm_master_requery),
1366                                         dlm_master_requery_handler,
1367                                         dlm, NULL, &dlm->dlm_domain_handlers);
1368         if (status)
1369                 goto bail;
1370
1371         status = o2net_register_handler(DLM_LOCK_REQUEST_MSG, dlm->key,
1372                                         sizeof(struct dlm_lock_request),
1373                                         dlm_request_all_locks_handler,
1374                                         dlm, NULL, &dlm->dlm_domain_handlers);
1375         if (status)
1376                 goto bail;
1377
1378         status = o2net_register_handler(DLM_RECO_DATA_DONE_MSG, dlm->key,
1379                                         sizeof(struct dlm_reco_data_done),
1380                                         dlm_reco_data_done_handler,
1381                                         dlm, NULL, &dlm->dlm_domain_handlers);
1382         if (status)
1383                 goto bail;
1384
1385         status = o2net_register_handler(DLM_BEGIN_RECO_MSG, dlm->key,
1386                                         sizeof(struct dlm_begin_reco),
1387                                         dlm_begin_reco_handler,
1388                                         dlm, NULL, &dlm->dlm_domain_handlers);
1389         if (status)
1390                 goto bail;
1391
1392         status = o2net_register_handler(DLM_FINALIZE_RECO_MSG, dlm->key,
1393                                         sizeof(struct dlm_finalize_reco),
1394                                         dlm_finalize_reco_handler,
1395                                         dlm, NULL, &dlm->dlm_domain_handlers);
1396         if (status)
1397                 goto bail;
1398
1399 bail:
1400         if (status)
1401                 dlm_unregister_domain_handlers(dlm);
1402
1403         return status;
1404 }
1405
1406 static int dlm_join_domain(struct dlm_ctxt *dlm)
1407 {
1408         int status;
1409         unsigned int backoff;
1410         unsigned int total_backoff = 0;
1411
1412         BUG_ON(!dlm);
1413
1414         mlog(0, "Join domain %s\n", dlm->name);
1415
1416         status = dlm_register_domain_handlers(dlm);
1417         if (status) {
1418                 mlog_errno(status);
1419                 goto bail;
1420         }
1421
1422         status = dlm_debug_init(dlm);
1423         if (status < 0) {
1424                 mlog_errno(status);
1425                 goto bail;
1426         }
1427
1428         status = dlm_launch_thread(dlm);
1429         if (status < 0) {
1430                 mlog_errno(status);
1431                 goto bail;
1432         }
1433
1434         status = dlm_launch_recovery_thread(dlm);
1435         if (status < 0) {
1436                 mlog_errno(status);
1437                 goto bail;
1438         }
1439
1440         dlm->dlm_worker = create_singlethread_workqueue("dlm_wq");
1441         if (!dlm->dlm_worker) {
1442                 status = -ENOMEM;
1443                 mlog_errno(status);
1444                 goto bail;
1445         }
1446
1447         do {
1448                 status = dlm_try_to_join_domain(dlm);
1449
1450                 /* If we're racing another node to the join, then we
1451                  * need to back off temporarily and let them
1452                  * complete. */
1453 #define DLM_JOIN_TIMEOUT_MSECS  90000
1454                 if (status == -EAGAIN) {
1455                         if (signal_pending(current)) {
1456                                 status = -ERESTARTSYS;
1457                                 goto bail;
1458                         }
1459
1460                         if (total_backoff >
1461                             msecs_to_jiffies(DLM_JOIN_TIMEOUT_MSECS)) {
1462                                 status = -ERESTARTSYS;
1463                                 mlog(ML_NOTICE, "Timed out joining dlm domain "
1464                                      "%s after %u msecs\n", dlm->name,
1465                                      jiffies_to_msecs(total_backoff));
1466                                 goto bail;
1467                         }
1468
1469                         /*
1470                          * <chip> After you!
1471                          * <dale> No, after you!
1472                          * <chip> I insist!
1473                          * <dale> But you first!
1474                          * ...
1475                          */
1476                         backoff = (unsigned int)(jiffies & 0x3);
1477                         backoff *= DLM_DOMAIN_BACKOFF_MS;
1478                         total_backoff += backoff;
1479                         mlog(0, "backoff %d\n", backoff);
1480                         msleep(backoff);
1481                 }
1482         } while (status == -EAGAIN);
1483
1484         if (status < 0) {
1485                 mlog_errno(status);
1486                 goto bail;
1487         }
1488
1489         status = 0;
1490 bail:
1491         wake_up(&dlm_domain_events);
1492
1493         if (status) {
1494                 dlm_unregister_domain_handlers(dlm);
1495                 dlm_debug_shutdown(dlm);
1496                 dlm_complete_thread(dlm);
1497                 dlm_complete_recovery_thread(dlm);
1498                 dlm_destroy_dlm_worker(dlm);
1499         }
1500
1501         return status;
1502 }
1503
1504 static struct dlm_ctxt *dlm_alloc_ctxt(const char *domain,
1505                                 u32 key)
1506 {
1507         int i;
1508         int ret;
1509         struct dlm_ctxt *dlm = NULL;
1510
1511         dlm = kzalloc(sizeof(*dlm), GFP_KERNEL);
1512         if (!dlm) {
1513                 mlog_errno(-ENOMEM);
1514                 goto leave;
1515         }
1516
1517         dlm->name = kmalloc(strlen(domain) + 1, GFP_KERNEL);
1518         if (dlm->name == NULL) {
1519                 mlog_errno(-ENOMEM);
1520                 kfree(dlm);
1521                 dlm = NULL;
1522                 goto leave;
1523         }
1524
1525         dlm->lockres_hash = (struct hlist_head **)dlm_alloc_pagevec(DLM_HASH_PAGES);
1526         if (!dlm->lockres_hash) {
1527                 mlog_errno(-ENOMEM);
1528                 kfree(dlm->name);
1529                 kfree(dlm);
1530                 dlm = NULL;
1531                 goto leave;
1532         }
1533
1534         for (i = 0; i < DLM_HASH_BUCKETS; i++)
1535                 INIT_HLIST_HEAD(dlm_lockres_hash(dlm, i));
1536
1537         strcpy(dlm->name, domain);
1538         dlm->key = key;
1539         dlm->node_num = o2nm_this_node();
1540
1541         ret = dlm_create_debugfs_subroot(dlm);
1542         if (ret < 0) {
1543                 dlm_free_pagevec((void **)dlm->lockres_hash, DLM_HASH_PAGES);
1544                 kfree(dlm->name);
1545                 kfree(dlm);
1546                 dlm = NULL;
1547                 goto leave;
1548         }
1549
1550         spin_lock_init(&dlm->spinlock);
1551         spin_lock_init(&dlm->master_lock);
1552         spin_lock_init(&dlm->ast_lock);
1553         spin_lock_init(&dlm->track_lock);
1554         INIT_LIST_HEAD(&dlm->list);
1555         INIT_LIST_HEAD(&dlm->dirty_list);
1556         INIT_LIST_HEAD(&dlm->reco.resources);
1557         INIT_LIST_HEAD(&dlm->reco.received);
1558         INIT_LIST_HEAD(&dlm->reco.node_data);
1559         INIT_LIST_HEAD(&dlm->purge_list);
1560         INIT_LIST_HEAD(&dlm->dlm_domain_handlers);
1561         INIT_LIST_HEAD(&dlm->tracking_list);
1562         dlm->reco.state = 0;
1563
1564         INIT_LIST_HEAD(&dlm->pending_asts);
1565         INIT_LIST_HEAD(&dlm->pending_basts);
1566
1567         mlog(0, "dlm->recovery_map=%p, &(dlm->recovery_map[0])=%p\n",
1568                   dlm->recovery_map, &(dlm->recovery_map[0]));
1569
1570         memset(dlm->recovery_map, 0, sizeof(dlm->recovery_map));
1571         memset(dlm->live_nodes_map, 0, sizeof(dlm->live_nodes_map));
1572         memset(dlm->domain_map, 0, sizeof(dlm->domain_map));
1573
1574         dlm->dlm_thread_task = NULL;
1575         dlm->dlm_reco_thread_task = NULL;
1576         dlm->dlm_worker = NULL;
1577         init_waitqueue_head(&dlm->dlm_thread_wq);
1578         init_waitqueue_head(&dlm->dlm_reco_thread_wq);
1579         init_waitqueue_head(&dlm->reco.event);
1580         init_waitqueue_head(&dlm->ast_wq);
1581         init_waitqueue_head(&dlm->migration_wq);
1582         INIT_LIST_HEAD(&dlm->master_list);
1583         INIT_LIST_HEAD(&dlm->mle_hb_events);
1584
1585         dlm->joining_node = DLM_LOCK_RES_OWNER_UNKNOWN;
1586         init_waitqueue_head(&dlm->dlm_join_events);
1587
1588         dlm->reco.new_master = O2NM_INVALID_NODE_NUM;
1589         dlm->reco.dead_node = O2NM_INVALID_NODE_NUM;
1590         atomic_set(&dlm->local_resources, 0);
1591         atomic_set(&dlm->remote_resources, 0);
1592         atomic_set(&dlm->unknown_resources, 0);
1593
1594         spin_lock_init(&dlm->work_lock);
1595         INIT_LIST_HEAD(&dlm->work_list);
1596         INIT_WORK(&dlm->dispatched_work, dlm_dispatch_work);
1597
1598         kref_init(&dlm->dlm_refs);
1599         dlm->dlm_state = DLM_CTXT_NEW;
1600
1601         INIT_LIST_HEAD(&dlm->dlm_eviction_callbacks);
1602
1603         mlog(0, "context init: refcount %u\n",
1604                   atomic_read(&dlm->dlm_refs.refcount));
1605
1606 leave:
1607         return dlm;
1608 }
1609
1610 /*
1611  * Compare a requested locking protocol version against the current one.
1612  *
1613  * If the major numbers are different, they are incompatible.
1614  * If the current minor is greater than the request, they are incompatible.
1615  * If the current minor is less than or equal to the request, they are
1616  * compatible, and the requester should run at the current minor version.
1617  */
1618 static int dlm_protocol_compare(struct dlm_protocol_version *existing,
1619                                 struct dlm_protocol_version *request)
1620 {
1621         if (existing->pv_major != request->pv_major)
1622                 return 1;
1623
1624         if (existing->pv_minor > request->pv_minor)
1625                 return 1;
1626
1627         if (existing->pv_minor < request->pv_minor)
1628                 request->pv_minor = existing->pv_minor;
1629
1630         return 0;
1631 }
1632
1633 /*
1634  * dlm_register_domain: one-time setup per "domain".
1635  *
1636  * The filesystem passes in the requested locking version via proto.
1637  * If registration was successful, proto will contain the negotiated
1638  * locking protocol.
1639  */
1640 struct dlm_ctxt * dlm_register_domain(const char *domain,
1641                                u32 key,
1642                                struct dlm_protocol_version *fs_proto)
1643 {
1644         int ret;
1645         struct dlm_ctxt *dlm = NULL;
1646         struct dlm_ctxt *new_ctxt = NULL;
1647
1648         if (strlen(domain) > O2NM_MAX_NAME_LEN) {
1649                 ret = -ENAMETOOLONG;
1650                 mlog(ML_ERROR, "domain name length too long\n");
1651                 goto leave;
1652         }
1653
1654         if (!o2hb_check_local_node_heartbeating()) {
1655                 mlog(ML_ERROR, "the local node has not been configured, or is "
1656                      "not heartbeating\n");
1657                 ret = -EPROTO;
1658                 goto leave;
1659         }
1660
1661         mlog(0, "register called for domain \"%s\"\n", domain);
1662
1663 retry:
1664         dlm = NULL;
1665         if (signal_pending(current)) {
1666                 ret = -ERESTARTSYS;
1667                 mlog_errno(ret);
1668                 goto leave;
1669         }
1670
1671         spin_lock(&dlm_domain_lock);
1672
1673         dlm = __dlm_lookup_domain(domain);
1674         if (dlm) {
1675                 if (dlm->dlm_state != DLM_CTXT_JOINED) {
1676                         spin_unlock(&dlm_domain_lock);
1677
1678                         mlog(0, "This ctxt is not joined yet!\n");
1679                         wait_event_interruptible(dlm_domain_events,
1680                                                  dlm_wait_on_domain_helper(
1681                                                          domain));
1682                         goto retry;
1683                 }
1684
1685                 if (dlm_protocol_compare(&dlm->fs_locking_proto, fs_proto)) {
1686                         mlog(ML_ERROR,
1687                              "Requested locking protocol version is not "
1688                              "compatible with already registered domain "
1689                              "\"%s\"\n", domain);
1690                         ret = -EPROTO;
1691                         goto leave;
1692                 }
1693
1694                 __dlm_get(dlm);
1695                 dlm->num_joins++;
1696
1697                 spin_unlock(&dlm_domain_lock);
1698
1699                 ret = 0;
1700                 goto leave;
1701         }
1702
1703         /* doesn't exist */
1704         if (!new_ctxt) {
1705                 spin_unlock(&dlm_domain_lock);
1706
1707                 new_ctxt = dlm_alloc_ctxt(domain, key);
1708                 if (new_ctxt)
1709                         goto retry;
1710
1711                 ret = -ENOMEM;
1712                 mlog_errno(ret);
1713                 goto leave;
1714         }
1715
1716         /* a little variable switch-a-roo here... */
1717         dlm = new_ctxt;
1718         new_ctxt = NULL;
1719
1720         /* add the new domain */
1721         list_add_tail(&dlm->list, &dlm_domains);
1722         spin_unlock(&dlm_domain_lock);
1723
1724         /*
1725          * Pass the locking protocol version into the join.  If the join
1726          * succeeds, it will have the negotiated protocol set.
1727          */
1728         dlm->dlm_locking_proto = dlm_protocol;
1729         dlm->fs_locking_proto = *fs_proto;
1730
1731         ret = dlm_join_domain(dlm);
1732         if (ret) {
1733                 mlog_errno(ret);
1734                 dlm_put(dlm);
1735                 goto leave;
1736         }
1737
1738         /* Tell the caller what locking protocol we negotiated */
1739         *fs_proto = dlm->fs_locking_proto;
1740
1741         ret = 0;
1742 leave:
1743         if (new_ctxt)
1744                 dlm_free_ctxt_mem(new_ctxt);
1745
1746         if (ret < 0)
1747                 dlm = ERR_PTR(ret);
1748
1749         return dlm;
1750 }
1751 EXPORT_SYMBOL_GPL(dlm_register_domain);
1752
1753 static LIST_HEAD(dlm_join_handlers);
1754
1755 static void dlm_unregister_net_handlers(void)
1756 {
1757         o2net_unregister_handler_list(&dlm_join_handlers);
1758 }
1759
1760 static int dlm_register_net_handlers(void)
1761 {
1762         int status = 0;
1763
1764         status = o2net_register_handler(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY,
1765                                         sizeof(struct dlm_query_join_request),
1766                                         dlm_query_join_handler,
1767                                         NULL, NULL, &dlm_join_handlers);
1768         if (status)
1769                 goto bail;
1770
1771         status = o2net_register_handler(DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
1772                                         sizeof(struct dlm_assert_joined),
1773                                         dlm_assert_joined_handler,
1774                                         NULL, NULL, &dlm_join_handlers);
1775         if (status)
1776                 goto bail;
1777
1778         status = o2net_register_handler(DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
1779                                         sizeof(struct dlm_cancel_join),
1780                                         dlm_cancel_join_handler,
1781                                         NULL, NULL, &dlm_join_handlers);
1782
1783 bail:
1784         if (status < 0)
1785                 dlm_unregister_net_handlers();
1786
1787         return status;
1788 }
1789
1790 /* Domain eviction callback handling.
1791  *
1792  * The file system requires notification of node death *before* the
1793  * dlm completes it's recovery work, otherwise it may be able to
1794  * acquire locks on resources requiring recovery. Since the dlm can
1795  * evict a node from it's domain *before* heartbeat fires, a similar
1796  * mechanism is required. */
1797
1798 /* Eviction is not expected to happen often, so a per-domain lock is
1799  * not necessary. Eviction callbacks are allowed to sleep for short
1800  * periods of time. */
1801 static DECLARE_RWSEM(dlm_callback_sem);
1802
1803 void dlm_fire_domain_eviction_callbacks(struct dlm_ctxt *dlm,
1804                                         int node_num)
1805 {
1806         struct list_head *iter;
1807         struct dlm_eviction_cb *cb;
1808
1809         down_read(&dlm_callback_sem);
1810         list_for_each(iter, &dlm->dlm_eviction_callbacks) {
1811                 cb = list_entry(iter, struct dlm_eviction_cb, ec_item);
1812
1813                 cb->ec_func(node_num, cb->ec_data);
1814         }
1815         up_read(&dlm_callback_sem);
1816 }
1817
1818 void dlm_setup_eviction_cb(struct dlm_eviction_cb *cb,
1819                            dlm_eviction_func *f,
1820                            void *data)
1821 {
1822         INIT_LIST_HEAD(&cb->ec_item);
1823         cb->ec_func = f;
1824         cb->ec_data = data;
1825 }
1826 EXPORT_SYMBOL_GPL(dlm_setup_eviction_cb);
1827
1828 void dlm_register_eviction_cb(struct dlm_ctxt *dlm,
1829                               struct dlm_eviction_cb *cb)
1830 {
1831         down_write(&dlm_callback_sem);
1832         list_add_tail(&cb->ec_item, &dlm->dlm_eviction_callbacks);
1833         up_write(&dlm_callback_sem);
1834 }
1835 EXPORT_SYMBOL_GPL(dlm_register_eviction_cb);
1836
1837 void dlm_unregister_eviction_cb(struct dlm_eviction_cb *cb)
1838 {
1839         down_write(&dlm_callback_sem);
1840         list_del_init(&cb->ec_item);
1841         up_write(&dlm_callback_sem);
1842 }
1843 EXPORT_SYMBOL_GPL(dlm_unregister_eviction_cb);
1844
1845 static int __init dlm_init(void)
1846 {
1847         int status;
1848
1849         dlm_print_version();
1850
1851         status = dlm_init_mle_cache();
1852         if (status) {
1853                 mlog(ML_ERROR, "Could not create o2dlm_mle slabcache\n");
1854                 goto error;
1855         }
1856
1857         status = dlm_init_master_caches();
1858         if (status) {
1859                 mlog(ML_ERROR, "Could not create o2dlm_lockres and "
1860                      "o2dlm_lockname slabcaches\n");
1861                 goto error;
1862         }
1863
1864         status = dlm_init_lock_cache();
1865         if (status) {
1866                 mlog(ML_ERROR, "Count not create o2dlm_lock slabcache\n");
1867                 goto error;
1868         }
1869
1870         status = dlm_register_net_handlers();
1871         if (status) {
1872                 mlog(ML_ERROR, "Unable to register network handlers\n");
1873                 goto error;
1874         }
1875
1876         status = dlm_create_debugfs_root();
1877         if (status)
1878                 goto error;
1879
1880         return 0;
1881 error:
1882         dlm_unregister_net_handlers();
1883         dlm_destroy_lock_cache();
1884         dlm_destroy_master_caches();
1885         dlm_destroy_mle_cache();
1886         return -1;
1887 }
1888
1889 static void __exit dlm_exit (void)
1890 {
1891         dlm_destroy_debugfs_root();
1892         dlm_unregister_net_handlers();
1893         dlm_destroy_lock_cache();
1894         dlm_destroy_master_caches();
1895         dlm_destroy_mle_cache();
1896 }
1897
1898 MODULE_AUTHOR("Oracle");
1899 MODULE_LICENSE("GPL");
1900
1901 module_init(dlm_init);
1902 module_exit(dlm_exit);