Merge git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6-nmw
[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
37 #include "cluster/heartbeat.h"
38 #include "cluster/nodemanager.h"
39 #include "cluster/tcp.h"
40
41 #include "dlmapi.h"
42 #include "dlmcommon.h"
43
44 #include "dlmdomain.h"
45
46 #include "dlmver.h"
47
48 #define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_DOMAIN)
49 #include "cluster/masklog.h"
50
51 /*
52  * ocfs2 node maps are array of long int, which limits to send them freely
53  * across the wire due to endianness issues. To workaround this, we convert
54  * long ints to byte arrays. Following 3 routines are helper functions to
55  * set/test/copy bits within those array of bytes
56  */
57 static inline void byte_set_bit(u8 nr, u8 map[])
58 {
59         map[nr >> 3] |= (1UL << (nr & 7));
60 }
61
62 static inline int byte_test_bit(u8 nr, u8 map[])
63 {
64         return ((1UL << (nr & 7)) & (map[nr >> 3])) != 0;
65 }
66
67 static inline void byte_copymap(u8 dmap[], unsigned long smap[],
68                         unsigned int sz)
69 {
70         unsigned int nn;
71
72         if (!sz)
73                 return;
74
75         memset(dmap, 0, ((sz + 7) >> 3));
76         for (nn = 0 ; nn < sz; nn++)
77                 if (test_bit(nn, smap))
78                         byte_set_bit(nn, dmap);
79 }
80
81 static void dlm_free_pagevec(void **vec, int pages)
82 {
83         while (pages--)
84                 free_page((unsigned long)vec[pages]);
85         kfree(vec);
86 }
87
88 static void **dlm_alloc_pagevec(int pages)
89 {
90         void **vec = kmalloc(pages * sizeof(void *), GFP_KERNEL);
91         int i;
92
93         if (!vec)
94                 return NULL;
95
96         for (i = 0; i < pages; i++)
97                 if (!(vec[i] = (void *)__get_free_page(GFP_KERNEL)))
98                         goto out_free;
99
100         mlog(0, "Allocated DLM hash pagevec; %d pages (%lu expected), %lu buckets per page\n",
101              pages, (unsigned long)DLM_HASH_PAGES,
102              (unsigned long)DLM_BUCKETS_PER_PAGE);
103         return vec;
104 out_free:
105         dlm_free_pagevec(vec, i);
106         return NULL;
107 }
108
109 /*
110  *
111  * spinlock lock ordering: if multiple locks are needed, obey this ordering:
112  *    dlm_domain_lock
113  *    struct dlm_ctxt->spinlock
114  *    struct dlm_lock_resource->spinlock
115  *    struct dlm_ctxt->master_lock
116  *    struct dlm_ctxt->ast_lock
117  *    dlm_master_list_entry->spinlock
118  *    dlm_lock->spinlock
119  *
120  */
121
122 DEFINE_SPINLOCK(dlm_domain_lock);
123 LIST_HEAD(dlm_domains);
124 static DECLARE_WAIT_QUEUE_HEAD(dlm_domain_events);
125
126 /*
127  * The supported protocol version for DLM communication.  Running domains
128  * will have a negotiated version with the same major number and a minor
129  * number equal or smaller.  The dlm_ctxt->dlm_locking_proto field should
130  * be used to determine what a running domain is actually using.
131  */
132 static const struct dlm_protocol_version dlm_protocol = {
133         .pv_major = 1,
134         .pv_minor = 0,
135 };
136
137 #define DLM_DOMAIN_BACKOFF_MS 200
138
139 static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
140                                   void **ret_data);
141 static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data,
142                                      void **ret_data);
143 static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data,
144                                    void **ret_data);
145 static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data,
146                                    void **ret_data);
147 static int dlm_protocol_compare(struct dlm_protocol_version *existing,
148                                 struct dlm_protocol_version *request);
149
150 static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm);
151
152 void __dlm_unhash_lockres(struct dlm_lock_resource *lockres)
153 {
154         if (!hlist_unhashed(&lockres->hash_node)) {
155                 hlist_del_init(&lockres->hash_node);
156                 dlm_lockres_put(lockres);
157         }
158 }
159
160 void __dlm_insert_lockres(struct dlm_ctxt *dlm,
161                        struct dlm_lock_resource *res)
162 {
163         struct hlist_head *bucket;
164         struct qstr *q;
165
166         assert_spin_locked(&dlm->spinlock);
167
168         q = &res->lockname;
169         bucket = dlm_lockres_hash(dlm, q->hash);
170
171         /* get a reference for our hashtable */
172         dlm_lockres_get(res);
173
174         hlist_add_head(&res->hash_node, bucket);
175 }
176
177 struct dlm_lock_resource * __dlm_lookup_lockres_full(struct dlm_ctxt *dlm,
178                                                      const char *name,
179                                                      unsigned int len,
180                                                      unsigned int hash)
181 {
182         struct hlist_head *bucket;
183         struct hlist_node *list;
184
185         mlog_entry("%.*s\n", len, name);
186
187         assert_spin_locked(&dlm->spinlock);
188
189         bucket = dlm_lockres_hash(dlm, hash);
190
191         hlist_for_each(list, bucket) {
192                 struct dlm_lock_resource *res = hlist_entry(list,
193                         struct dlm_lock_resource, hash_node);
194                 if (res->lockname.name[0] != name[0])
195                         continue;
196                 if (unlikely(res->lockname.len != len))
197                         continue;
198                 if (memcmp(res->lockname.name + 1, name + 1, len - 1))
199                         continue;
200                 dlm_lockres_get(res);
201                 return res;
202         }
203         return NULL;
204 }
205
206 /* intended to be called by functions which do not care about lock
207  * resources which are being purged (most net _handler functions).
208  * this will return NULL for any lock resource which is found but
209  * currently in the process of dropping its mastery reference.
210  * use __dlm_lookup_lockres_full when you need the lock resource
211  * regardless (e.g. dlm_get_lock_resource) */
212 struct dlm_lock_resource * __dlm_lookup_lockres(struct dlm_ctxt *dlm,
213                                                 const char *name,
214                                                 unsigned int len,
215                                                 unsigned int hash)
216 {
217         struct dlm_lock_resource *res = NULL;
218
219         mlog_entry("%.*s\n", len, name);
220
221         assert_spin_locked(&dlm->spinlock);
222
223         res = __dlm_lookup_lockres_full(dlm, name, len, hash);
224         if (res) {
225                 spin_lock(&res->spinlock);
226                 if (res->state & DLM_LOCK_RES_DROPPING_REF) {
227                         spin_unlock(&res->spinlock);
228                         dlm_lockres_put(res);
229                         return NULL;
230                 }
231                 spin_unlock(&res->spinlock);
232         }
233
234         return res;
235 }
236
237 struct dlm_lock_resource * dlm_lookup_lockres(struct dlm_ctxt *dlm,
238                                     const char *name,
239                                     unsigned int len)
240 {
241         struct dlm_lock_resource *res;
242         unsigned int hash = dlm_lockid_hash(name, len);
243
244         spin_lock(&dlm->spinlock);
245         res = __dlm_lookup_lockres(dlm, name, len, hash);
246         spin_unlock(&dlm->spinlock);
247         return res;
248 }
249
250 static struct dlm_ctxt * __dlm_lookup_domain_full(const char *domain, int len)
251 {
252         struct dlm_ctxt *tmp = NULL;
253         struct list_head *iter;
254
255         assert_spin_locked(&dlm_domain_lock);
256
257         /* tmp->name here is always NULL terminated,
258          * but domain may not be! */
259         list_for_each(iter, &dlm_domains) {
260                 tmp = list_entry (iter, struct dlm_ctxt, list);
261                 if (strlen(tmp->name) == len &&
262                     memcmp(tmp->name, domain, len)==0)
263                         break;
264                 tmp = NULL;
265         }
266
267         return tmp;
268 }
269
270 /* For null terminated domain strings ONLY */
271 static struct dlm_ctxt * __dlm_lookup_domain(const char *domain)
272 {
273         assert_spin_locked(&dlm_domain_lock);
274
275         return __dlm_lookup_domain_full(domain, strlen(domain));
276 }
277
278
279 /* returns true on one of two conditions:
280  * 1) the domain does not exist
281  * 2) the domain exists and it's state is "joined" */
282 static int dlm_wait_on_domain_helper(const char *domain)
283 {
284         int ret = 0;
285         struct dlm_ctxt *tmp = NULL;
286
287         spin_lock(&dlm_domain_lock);
288
289         tmp = __dlm_lookup_domain(domain);
290         if (!tmp)
291                 ret = 1;
292         else if (tmp->dlm_state == DLM_CTXT_JOINED)
293                 ret = 1;
294
295         spin_unlock(&dlm_domain_lock);
296         return ret;
297 }
298
299 static void dlm_free_ctxt_mem(struct dlm_ctxt *dlm)
300 {
301         if (dlm->lockres_hash)
302                 dlm_free_pagevec((void **)dlm->lockres_hash, DLM_HASH_PAGES);
303
304         if (dlm->name)
305                 kfree(dlm->name);
306
307         kfree(dlm);
308 }
309
310 /* A little strange - this function will be called while holding
311  * dlm_domain_lock and is expected to be holding it on the way out. We
312  * will however drop and reacquire it multiple times */
313 static void dlm_ctxt_release(struct kref *kref)
314 {
315         struct dlm_ctxt *dlm;
316
317         dlm = container_of(kref, struct dlm_ctxt, dlm_refs);
318
319         BUG_ON(dlm->num_joins);
320         BUG_ON(dlm->dlm_state == DLM_CTXT_JOINED);
321
322         /* we may still be in the list if we hit an error during join. */
323         list_del_init(&dlm->list);
324
325         spin_unlock(&dlm_domain_lock);
326
327         mlog(0, "freeing memory from domain %s\n", dlm->name);
328
329         wake_up(&dlm_domain_events);
330
331         dlm_free_ctxt_mem(dlm);
332
333         spin_lock(&dlm_domain_lock);
334 }
335
336 void dlm_put(struct dlm_ctxt *dlm)
337 {
338         spin_lock(&dlm_domain_lock);
339         kref_put(&dlm->dlm_refs, dlm_ctxt_release);
340         spin_unlock(&dlm_domain_lock);
341 }
342
343 static void __dlm_get(struct dlm_ctxt *dlm)
344 {
345         kref_get(&dlm->dlm_refs);
346 }
347
348 /* given a questionable reference to a dlm object, gets a reference if
349  * it can find it in the list, otherwise returns NULL in which case
350  * you shouldn't trust your pointer. */
351 struct dlm_ctxt *dlm_grab(struct dlm_ctxt *dlm)
352 {
353         struct list_head *iter;
354         struct dlm_ctxt *target = NULL;
355
356         spin_lock(&dlm_domain_lock);
357
358         list_for_each(iter, &dlm_domains) {
359                 target = list_entry (iter, struct dlm_ctxt, list);
360
361                 if (target == dlm) {
362                         __dlm_get(target);
363                         break;
364                 }
365
366                 target = NULL;
367         }
368
369         spin_unlock(&dlm_domain_lock);
370
371         return target;
372 }
373
374 int dlm_domain_fully_joined(struct dlm_ctxt *dlm)
375 {
376         int ret;
377
378         spin_lock(&dlm_domain_lock);
379         ret = (dlm->dlm_state == DLM_CTXT_JOINED) ||
380                 (dlm->dlm_state == DLM_CTXT_IN_SHUTDOWN);
381         spin_unlock(&dlm_domain_lock);
382
383         return ret;
384 }
385
386 static void dlm_destroy_dlm_worker(struct dlm_ctxt *dlm)
387 {
388         if (dlm->dlm_worker) {
389                 flush_workqueue(dlm->dlm_worker);
390                 destroy_workqueue(dlm->dlm_worker);
391                 dlm->dlm_worker = NULL;
392         }
393 }
394
395 static void dlm_complete_dlm_shutdown(struct dlm_ctxt *dlm)
396 {
397         dlm_unregister_domain_handlers(dlm);
398         dlm_complete_thread(dlm);
399         dlm_complete_recovery_thread(dlm);
400         dlm_destroy_dlm_worker(dlm);
401
402         /* We've left the domain. Now we can take ourselves out of the
403          * list and allow the kref stuff to help us free the
404          * memory. */
405         spin_lock(&dlm_domain_lock);
406         list_del_init(&dlm->list);
407         spin_unlock(&dlm_domain_lock);
408
409         /* Wake up anyone waiting for us to remove this domain */
410         wake_up(&dlm_domain_events);
411 }
412
413 static int dlm_migrate_all_locks(struct dlm_ctxt *dlm)
414 {
415         int i, num, n, ret = 0;
416         struct dlm_lock_resource *res;
417         struct hlist_node *iter;
418         struct hlist_head *bucket;
419         int dropped;
420
421         mlog(0, "Migrating locks from domain %s\n", dlm->name);
422
423         num = 0;
424         spin_lock(&dlm->spinlock);
425         for (i = 0; i < DLM_HASH_BUCKETS; i++) {
426 redo_bucket:
427                 n = 0;
428                 bucket = dlm_lockres_hash(dlm, i);
429                 iter = bucket->first;
430                 while (iter) {
431                         n++;
432                         res = hlist_entry(iter, struct dlm_lock_resource,
433                                           hash_node);
434                         dlm_lockres_get(res);
435                         /* migrate, if necessary.  this will drop the dlm
436                          * spinlock and retake it if it does migration. */
437                         dropped = dlm_empty_lockres(dlm, res);
438
439                         spin_lock(&res->spinlock);
440                         __dlm_lockres_calc_usage(dlm, res);
441                         iter = res->hash_node.next;
442                         spin_unlock(&res->spinlock);
443
444                         dlm_lockres_put(res);
445
446                         if (dropped)
447                                 goto redo_bucket;
448                 }
449                 cond_resched_lock(&dlm->spinlock);
450                 num += n;
451                 mlog(0, "%s: touched %d lockreses in bucket %d "
452                      "(tot=%d)\n", dlm->name, n, i, num);
453         }
454         spin_unlock(&dlm->spinlock);
455         wake_up(&dlm->dlm_thread_wq);
456
457         /* let the dlm thread take care of purging, keep scanning until
458          * nothing remains in the hash */
459         if (num) {
460                 mlog(0, "%s: %d lock resources in hash last pass\n",
461                      dlm->name, num);
462                 ret = -EAGAIN;
463         }
464         mlog(0, "DONE Migrating locks from domain %s\n", dlm->name);
465         return ret;
466 }
467
468 static int dlm_no_joining_node(struct dlm_ctxt *dlm)
469 {
470         int ret;
471
472         spin_lock(&dlm->spinlock);
473         ret = dlm->joining_node == DLM_LOCK_RES_OWNER_UNKNOWN;
474         spin_unlock(&dlm->spinlock);
475
476         return ret;
477 }
478
479 static void dlm_mark_domain_leaving(struct dlm_ctxt *dlm)
480 {
481         /* Yikes, a double spinlock! I need domain_lock for the dlm
482          * state and the dlm spinlock for join state... Sorry! */
483 again:
484         spin_lock(&dlm_domain_lock);
485         spin_lock(&dlm->spinlock);
486
487         if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
488                 mlog(0, "Node %d is joining, we wait on it.\n",
489                           dlm->joining_node);
490                 spin_unlock(&dlm->spinlock);
491                 spin_unlock(&dlm_domain_lock);
492
493                 wait_event(dlm->dlm_join_events, dlm_no_joining_node(dlm));
494                 goto again;
495         }
496
497         dlm->dlm_state = DLM_CTXT_LEAVING;
498         spin_unlock(&dlm->spinlock);
499         spin_unlock(&dlm_domain_lock);
500 }
501
502 static void __dlm_print_nodes(struct dlm_ctxt *dlm)
503 {
504         int node = -1;
505
506         assert_spin_locked(&dlm->spinlock);
507
508         printk(KERN_INFO "ocfs2_dlm: Nodes in domain (\"%s\"): ", dlm->name);
509
510         while ((node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES,
511                                      node + 1)) < O2NM_MAX_NODES) {
512                 printk("%d ", node);
513         }
514         printk("\n");
515 }
516
517 static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data,
518                                    void **ret_data)
519 {
520         struct dlm_ctxt *dlm = data;
521         unsigned int node;
522         struct dlm_exit_domain *exit_msg = (struct dlm_exit_domain *) msg->buf;
523
524         mlog_entry("%p %u %p", msg, len, data);
525
526         if (!dlm_grab(dlm))
527                 return 0;
528
529         node = exit_msg->node_idx;
530
531         printk(KERN_INFO "ocfs2_dlm: Node %u leaves domain %s\n", node, dlm->name);
532
533         spin_lock(&dlm->spinlock);
534         clear_bit(node, dlm->domain_map);
535         __dlm_print_nodes(dlm);
536
537         /* notify anything attached to the heartbeat events */
538         dlm_hb_event_notify_attached(dlm, node, 0);
539
540         spin_unlock(&dlm->spinlock);
541
542         dlm_put(dlm);
543
544         return 0;
545 }
546
547 static int dlm_send_one_domain_exit(struct dlm_ctxt *dlm,
548                                     unsigned int node)
549 {
550         int status;
551         struct dlm_exit_domain leave_msg;
552
553         mlog(0, "Asking node %u if we can leave the domain %s me = %u\n",
554                   node, dlm->name, dlm->node_num);
555
556         memset(&leave_msg, 0, sizeof(leave_msg));
557         leave_msg.node_idx = dlm->node_num;
558
559         status = o2net_send_message(DLM_EXIT_DOMAIN_MSG, dlm->key,
560                                     &leave_msg, sizeof(leave_msg), node,
561                                     NULL);
562
563         mlog(0, "status return %d from o2net_send_message\n", status);
564
565         return status;
566 }
567
568
569 static void dlm_leave_domain(struct dlm_ctxt *dlm)
570 {
571         int node, clear_node, status;
572
573         /* At this point we've migrated away all our locks and won't
574          * accept mastership of new ones. The dlm is responsible for
575          * almost nothing now. We make sure not to confuse any joining
576          * nodes and then commence shutdown procedure. */
577
578         spin_lock(&dlm->spinlock);
579         /* Clear ourselves from the domain map */
580         clear_bit(dlm->node_num, dlm->domain_map);
581         while ((node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES,
582                                      0)) < O2NM_MAX_NODES) {
583                 /* Drop the dlm spinlock. This is safe wrt the domain_map.
584                  * -nodes cannot be added now as the
585                  *   query_join_handlers knows to respond with OK_NO_MAP
586                  * -we catch the right network errors if a node is
587                  *   removed from the map while we're sending him the
588                  *   exit message. */
589                 spin_unlock(&dlm->spinlock);
590
591                 clear_node = 1;
592
593                 status = dlm_send_one_domain_exit(dlm, node);
594                 if (status < 0 &&
595                     status != -ENOPROTOOPT &&
596                     status != -ENOTCONN) {
597                         mlog(ML_NOTICE, "Error %d sending domain exit message "
598                              "to node %d\n", status, node);
599
600                         /* Not sure what to do here but lets sleep for
601                          * a bit in case this was a transient
602                          * error... */
603                         msleep(DLM_DOMAIN_BACKOFF_MS);
604                         clear_node = 0;
605                 }
606
607                 spin_lock(&dlm->spinlock);
608                 /* If we're not clearing the node bit then we intend
609                  * to loop back around to try again. */
610                 if (clear_node)
611                         clear_bit(node, dlm->domain_map);
612         }
613         spin_unlock(&dlm->spinlock);
614 }
615
616 int dlm_joined(struct dlm_ctxt *dlm)
617 {
618         int ret = 0;
619
620         spin_lock(&dlm_domain_lock);
621
622         if (dlm->dlm_state == DLM_CTXT_JOINED)
623                 ret = 1;
624
625         spin_unlock(&dlm_domain_lock);
626
627         return ret;
628 }
629
630 int dlm_shutting_down(struct dlm_ctxt *dlm)
631 {
632         int ret = 0;
633
634         spin_lock(&dlm_domain_lock);
635
636         if (dlm->dlm_state == DLM_CTXT_IN_SHUTDOWN)
637                 ret = 1;
638
639         spin_unlock(&dlm_domain_lock);
640
641         return ret;
642 }
643
644 void dlm_unregister_domain(struct dlm_ctxt *dlm)
645 {
646         int leave = 0;
647
648         spin_lock(&dlm_domain_lock);
649         BUG_ON(dlm->dlm_state != DLM_CTXT_JOINED);
650         BUG_ON(!dlm->num_joins);
651
652         dlm->num_joins--;
653         if (!dlm->num_joins) {
654                 /* We mark it "in shutdown" now so new register
655                  * requests wait until we've completely left the
656                  * domain. Don't use DLM_CTXT_LEAVING yet as we still
657                  * want new domain joins to communicate with us at
658                  * least until we've completed migration of our
659                  * resources. */
660                 dlm->dlm_state = DLM_CTXT_IN_SHUTDOWN;
661                 leave = 1;
662         }
663         spin_unlock(&dlm_domain_lock);
664
665         if (leave) {
666                 mlog(0, "shutting down domain %s\n", dlm->name);
667
668                 /* We changed dlm state, notify the thread */
669                 dlm_kick_thread(dlm, NULL);
670
671                 while (dlm_migrate_all_locks(dlm)) {
672                         /* Give dlm_thread time to purge the lockres' */
673                         msleep(500);
674                         mlog(0, "%s: more migration to do\n", dlm->name);
675                 }
676                 dlm_mark_domain_leaving(dlm);
677                 dlm_leave_domain(dlm);
678                 dlm_complete_dlm_shutdown(dlm);
679         }
680         dlm_put(dlm);
681 }
682 EXPORT_SYMBOL_GPL(dlm_unregister_domain);
683
684 static int dlm_query_join_proto_check(char *proto_type, int node,
685                                       struct dlm_protocol_version *ours,
686                                       struct dlm_protocol_version *request)
687 {
688         int rc;
689         struct dlm_protocol_version proto = *request;
690
691         if (!dlm_protocol_compare(ours, &proto)) {
692                 mlog(0,
693                      "node %u wanted to join with %s locking protocol "
694                      "%u.%u, we respond with %u.%u\n",
695                      node, proto_type,
696                      request->pv_major,
697                      request->pv_minor,
698                      proto.pv_major, proto.pv_minor);
699                 request->pv_minor = proto.pv_minor;
700                 rc = 0;
701         } else {
702                 mlog(ML_NOTICE,
703                      "Node %u wanted to join with %s locking "
704                      "protocol %u.%u, but we have %u.%u, disallowing\n",
705                      node, proto_type,
706                      request->pv_major,
707                      request->pv_minor,
708                      ours->pv_major,
709                      ours->pv_minor);
710                 rc = 1;
711         }
712
713         return rc;
714 }
715
716 /*
717  * struct dlm_query_join_packet is made up of four one-byte fields.  They
718  * are effectively in big-endian order already.  However, little-endian
719  * machines swap them before putting the packet on the wire (because
720  * query_join's response is a status, and that status is treated as a u32
721  * on the wire).  Thus, a big-endian and little-endian machines will treat
722  * this structure differently.
723  *
724  * The solution is to have little-endian machines swap the structure when
725  * converting from the structure to the u32 representation.  This will
726  * result in the structure having the correct format on the wire no matter
727  * the host endian format.
728  */
729 static void dlm_query_join_packet_to_wire(struct dlm_query_join_packet *packet,
730                                           u32 *wire)
731 {
732         union dlm_query_join_response response;
733
734         response.packet = *packet;
735         *wire = cpu_to_be32(response.intval);
736 }
737
738 static void dlm_query_join_wire_to_packet(u32 wire,
739                                           struct dlm_query_join_packet *packet)
740 {
741         union dlm_query_join_response response;
742
743         response.intval = cpu_to_be32(wire);
744         *packet = response.packet;
745 }
746
747 static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
748                                   void **ret_data)
749 {
750         struct dlm_query_join_request *query;
751         struct dlm_query_join_packet packet = {
752                 .code = JOIN_DISALLOW,
753         };
754         struct dlm_ctxt *dlm = NULL;
755         u32 response;
756         u8 nodenum;
757
758         query = (struct dlm_query_join_request *) msg->buf;
759
760         mlog(0, "node %u wants to join domain %s\n", query->node_idx,
761                   query->domain);
762
763         /*
764          * If heartbeat doesn't consider the node live, tell it
765          * to back off and try again.  This gives heartbeat a chance
766          * to catch up.
767          */
768         if (!o2hb_check_node_heartbeating(query->node_idx)) {
769                 mlog(0, "node %u is not in our live map yet\n",
770                      query->node_idx);
771
772                 packet.code = JOIN_DISALLOW;
773                 goto respond;
774         }
775
776         packet.code = JOIN_OK_NO_MAP;
777
778         spin_lock(&dlm_domain_lock);
779         dlm = __dlm_lookup_domain_full(query->domain, query->name_len);
780         if (!dlm)
781                 goto unlock_respond;
782
783         /*
784          * There is a small window where the joining node may not see the
785          * node(s) that just left but still part of the cluster. DISALLOW
786          * join request if joining node has different node map.
787          */
788         nodenum=0;
789         while (nodenum < O2NM_MAX_NODES) {
790                 if (test_bit(nodenum, dlm->domain_map)) {
791                         if (!byte_test_bit(nodenum, query->node_map)) {
792                                 mlog(0, "disallow join as node %u does not "
793                                      "have node %u in its nodemap\n",
794                                      query->node_idx, nodenum);
795                                 packet.code = JOIN_DISALLOW;
796                                 goto unlock_respond;
797                         }
798                 }
799                 nodenum++;
800         }
801
802         /* Once the dlm ctxt is marked as leaving then we don't want
803          * to be put in someone's domain map. 
804          * Also, explicitly disallow joining at certain troublesome
805          * times (ie. during recovery). */
806         if (dlm && dlm->dlm_state != DLM_CTXT_LEAVING) {
807                 int bit = query->node_idx;
808                 spin_lock(&dlm->spinlock);
809
810                 if (dlm->dlm_state == DLM_CTXT_NEW &&
811                     dlm->joining_node == DLM_LOCK_RES_OWNER_UNKNOWN) {
812                         /*If this is a brand new context and we
813                          * haven't started our join process yet, then
814                          * the other node won the race. */
815                         packet.code = JOIN_OK_NO_MAP;
816                 } else if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
817                         /* Disallow parallel joins. */
818                         packet.code = JOIN_DISALLOW;
819                 } else if (dlm->reco.state & DLM_RECO_STATE_ACTIVE) {
820                         mlog(0, "node %u trying to join, but recovery "
821                              "is ongoing.\n", bit);
822                         packet.code = JOIN_DISALLOW;
823                 } else if (test_bit(bit, dlm->recovery_map)) {
824                         mlog(0, "node %u trying to join, but it "
825                              "still needs recovery.\n", bit);
826                         packet.code = JOIN_DISALLOW;
827                 } else if (test_bit(bit, dlm->domain_map)) {
828                         mlog(0, "node %u trying to join, but it "
829                              "is still in the domain! needs recovery?\n",
830                              bit);
831                         packet.code = JOIN_DISALLOW;
832                 } else {
833                         /* Alright we're fully a part of this domain
834                          * so we keep some state as to who's joining
835                          * and indicate to him that needs to be fixed
836                          * up. */
837
838                         /* Make sure we speak compatible locking protocols.  */
839                         if (dlm_query_join_proto_check("DLM", bit,
840                                                        &dlm->dlm_locking_proto,
841                                                        &query->dlm_proto)) {
842                                 packet.code = JOIN_PROTOCOL_MISMATCH;
843                         } else if (dlm_query_join_proto_check("fs", bit,
844                                                               &dlm->fs_locking_proto,
845                                                               &query->fs_proto)) {
846                                 packet.code = JOIN_PROTOCOL_MISMATCH;
847                         } else {
848                                 packet.dlm_minor = query->dlm_proto.pv_minor;
849                                 packet.fs_minor = query->fs_proto.pv_minor;
850                                 packet.code = JOIN_OK;
851                                 __dlm_set_joining_node(dlm, query->node_idx);
852                         }
853                 }
854
855                 spin_unlock(&dlm->spinlock);
856         }
857 unlock_respond:
858         spin_unlock(&dlm_domain_lock);
859
860 respond:
861         mlog(0, "We respond with %u\n", packet.code);
862
863         dlm_query_join_packet_to_wire(&packet, &response);
864         return response;
865 }
866
867 static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data,
868                                      void **ret_data)
869 {
870         struct dlm_assert_joined *assert;
871         struct dlm_ctxt *dlm = NULL;
872
873         assert = (struct dlm_assert_joined *) msg->buf;
874
875         mlog(0, "node %u asserts join on domain %s\n", assert->node_idx,
876                   assert->domain);
877
878         spin_lock(&dlm_domain_lock);
879         dlm = __dlm_lookup_domain_full(assert->domain, assert->name_len);
880         /* XXX should we consider no dlm ctxt an error? */
881         if (dlm) {
882                 spin_lock(&dlm->spinlock);
883
884                 /* Alright, this node has officially joined our
885                  * domain. Set him in the map and clean up our
886                  * leftover join state. */
887                 BUG_ON(dlm->joining_node != assert->node_idx);
888                 set_bit(assert->node_idx, dlm->domain_map);
889                 __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
890
891                 printk(KERN_INFO "ocfs2_dlm: Node %u joins domain %s\n",
892                        assert->node_idx, dlm->name);
893                 __dlm_print_nodes(dlm);
894
895                 /* notify anything attached to the heartbeat events */
896                 dlm_hb_event_notify_attached(dlm, assert->node_idx, 1);
897
898                 spin_unlock(&dlm->spinlock);
899         }
900         spin_unlock(&dlm_domain_lock);
901
902         return 0;
903 }
904
905 static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data,
906                                    void **ret_data)
907 {
908         struct dlm_cancel_join *cancel;
909         struct dlm_ctxt *dlm = NULL;
910
911         cancel = (struct dlm_cancel_join *) msg->buf;
912
913         mlog(0, "node %u cancels join on domain %s\n", cancel->node_idx,
914                   cancel->domain);
915
916         spin_lock(&dlm_domain_lock);
917         dlm = __dlm_lookup_domain_full(cancel->domain, cancel->name_len);
918
919         if (dlm) {
920                 spin_lock(&dlm->spinlock);
921
922                 /* Yikes, this guy wants to cancel his join. No
923                  * problem, we simply cleanup our join state. */
924                 BUG_ON(dlm->joining_node != cancel->node_idx);
925                 __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
926
927                 spin_unlock(&dlm->spinlock);
928         }
929         spin_unlock(&dlm_domain_lock);
930
931         return 0;
932 }
933
934 static int dlm_send_one_join_cancel(struct dlm_ctxt *dlm,
935                                     unsigned int node)
936 {
937         int status;
938         struct dlm_cancel_join cancel_msg;
939
940         memset(&cancel_msg, 0, sizeof(cancel_msg));
941         cancel_msg.node_idx = dlm->node_num;
942         cancel_msg.name_len = strlen(dlm->name);
943         memcpy(cancel_msg.domain, dlm->name, cancel_msg.name_len);
944
945         status = o2net_send_message(DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
946                                     &cancel_msg, sizeof(cancel_msg), node,
947                                     NULL);
948         if (status < 0) {
949                 mlog_errno(status);
950                 goto bail;
951         }
952
953 bail:
954         return status;
955 }
956
957 /* map_size should be in bytes. */
958 static int dlm_send_join_cancels(struct dlm_ctxt *dlm,
959                                  unsigned long *node_map,
960                                  unsigned int map_size)
961 {
962         int status, tmpstat;
963         unsigned int node;
964
965         if (map_size != (BITS_TO_LONGS(O2NM_MAX_NODES) *
966                          sizeof(unsigned long))) {
967                 mlog(ML_ERROR,
968                      "map_size %u != BITS_TO_LONGS(O2NM_MAX_NODES) %u\n",
969                      map_size, (unsigned)BITS_TO_LONGS(O2NM_MAX_NODES));
970                 return -EINVAL;
971         }
972
973         status = 0;
974         node = -1;
975         while ((node = find_next_bit(node_map, O2NM_MAX_NODES,
976                                      node + 1)) < O2NM_MAX_NODES) {
977                 if (node == dlm->node_num)
978                         continue;
979
980                 tmpstat = dlm_send_one_join_cancel(dlm, node);
981                 if (tmpstat) {
982                         mlog(ML_ERROR, "Error return %d cancelling join on "
983                              "node %d\n", tmpstat, node);
984                         if (!status)
985                                 status = tmpstat;
986                 }
987         }
988
989         if (status)
990                 mlog_errno(status);
991         return status;
992 }
993
994 static int dlm_request_join(struct dlm_ctxt *dlm,
995                             int node,
996                             enum dlm_query_join_response_code *response)
997 {
998         int status;
999         struct dlm_query_join_request join_msg;
1000         struct dlm_query_join_packet packet;
1001         u32 join_resp;
1002
1003         mlog(0, "querying node %d\n", node);
1004
1005         memset(&join_msg, 0, sizeof(join_msg));
1006         join_msg.node_idx = dlm->node_num;
1007         join_msg.name_len = strlen(dlm->name);
1008         memcpy(join_msg.domain, dlm->name, join_msg.name_len);
1009         join_msg.dlm_proto = dlm->dlm_locking_proto;
1010         join_msg.fs_proto = dlm->fs_locking_proto;
1011
1012         /* copy live node map to join message */
1013         byte_copymap(join_msg.node_map, dlm->live_nodes_map, O2NM_MAX_NODES);
1014
1015         status = o2net_send_message(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY, &join_msg,
1016                                     sizeof(join_msg), node,
1017                                     &join_resp);
1018         if (status < 0 && status != -ENOPROTOOPT) {
1019                 mlog_errno(status);
1020                 goto bail;
1021         }
1022         dlm_query_join_wire_to_packet(join_resp, &packet);
1023
1024         /* -ENOPROTOOPT from the net code means the other side isn't
1025             listening for our message type -- that's fine, it means
1026             his dlm isn't up, so we can consider him a 'yes' but not
1027             joined into the domain.  */
1028         if (status == -ENOPROTOOPT) {
1029                 status = 0;
1030                 *response = JOIN_OK_NO_MAP;
1031         } else if (packet.code == JOIN_DISALLOW ||
1032                    packet.code == JOIN_OK_NO_MAP) {
1033                 *response = packet.code;
1034         } else if (packet.code == JOIN_PROTOCOL_MISMATCH) {
1035                 mlog(ML_NOTICE,
1036                      "This node requested DLM locking protocol %u.%u and "
1037                      "filesystem locking protocol %u.%u.  At least one of "
1038                      "the protocol versions on node %d is not compatible, "
1039                      "disconnecting\n",
1040                      dlm->dlm_locking_proto.pv_major,
1041                      dlm->dlm_locking_proto.pv_minor,
1042                      dlm->fs_locking_proto.pv_major,
1043                      dlm->fs_locking_proto.pv_minor,
1044                      node);
1045                 status = -EPROTO;
1046                 *response = packet.code;
1047         } else if (packet.code == JOIN_OK) {
1048                 *response = packet.code;
1049                 /* Use the same locking protocol as the remote node */
1050                 dlm->dlm_locking_proto.pv_minor = packet.dlm_minor;
1051                 dlm->fs_locking_proto.pv_minor = packet.fs_minor;
1052                 mlog(0,
1053                      "Node %d responds JOIN_OK with DLM locking protocol "
1054                      "%u.%u and fs locking protocol %u.%u\n",
1055                      node,
1056                      dlm->dlm_locking_proto.pv_major,
1057                      dlm->dlm_locking_proto.pv_minor,
1058                      dlm->fs_locking_proto.pv_major,
1059                      dlm->fs_locking_proto.pv_minor);
1060         } else {
1061                 status = -EINVAL;
1062                 mlog(ML_ERROR, "invalid response %d from node %u\n",
1063                      packet.code, node);
1064         }
1065
1066         mlog(0, "status %d, node %d response is %d\n", status, node,
1067              *response);
1068
1069 bail:
1070         return status;
1071 }
1072
1073 static int dlm_send_one_join_assert(struct dlm_ctxt *dlm,
1074                                     unsigned int node)
1075 {
1076         int status;
1077         struct dlm_assert_joined assert_msg;
1078
1079         mlog(0, "Sending join assert to node %u\n", node);
1080
1081         memset(&assert_msg, 0, sizeof(assert_msg));
1082         assert_msg.node_idx = dlm->node_num;
1083         assert_msg.name_len = strlen(dlm->name);
1084         memcpy(assert_msg.domain, dlm->name, assert_msg.name_len);
1085
1086         status = o2net_send_message(DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
1087                                     &assert_msg, sizeof(assert_msg), node,
1088                                     NULL);
1089         if (status < 0)
1090                 mlog_errno(status);
1091
1092         return status;
1093 }
1094
1095 static void dlm_send_join_asserts(struct dlm_ctxt *dlm,
1096                                   unsigned long *node_map)
1097 {
1098         int status, node, live;
1099
1100         status = 0;
1101         node = -1;
1102         while ((node = find_next_bit(node_map, O2NM_MAX_NODES,
1103                                      node + 1)) < O2NM_MAX_NODES) {
1104                 if (node == dlm->node_num)
1105                         continue;
1106
1107                 do {
1108                         /* It is very important that this message be
1109                          * received so we spin until either the node
1110                          * has died or it gets the message. */
1111                         status = dlm_send_one_join_assert(dlm, node);
1112
1113                         spin_lock(&dlm->spinlock);
1114                         live = test_bit(node, dlm->live_nodes_map);
1115                         spin_unlock(&dlm->spinlock);
1116
1117                         if (status) {
1118                                 mlog(ML_ERROR, "Error return %d asserting "
1119                                      "join on node %d\n", status, node);
1120
1121                                 /* give us some time between errors... */
1122                                 if (live)
1123                                         msleep(DLM_DOMAIN_BACKOFF_MS);
1124                         }
1125                 } while (status && live);
1126         }
1127 }
1128
1129 struct domain_join_ctxt {
1130         unsigned long live_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1131         unsigned long yes_resp_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1132 };
1133
1134 static int dlm_should_restart_join(struct dlm_ctxt *dlm,
1135                                    struct domain_join_ctxt *ctxt,
1136                                    enum dlm_query_join_response_code response)
1137 {
1138         int ret;
1139
1140         if (response == JOIN_DISALLOW) {
1141                 mlog(0, "Latest response of disallow -- should restart\n");
1142                 return 1;
1143         }
1144
1145         spin_lock(&dlm->spinlock);
1146         /* For now, we restart the process if the node maps have
1147          * changed at all */
1148         ret = memcmp(ctxt->live_map, dlm->live_nodes_map,
1149                      sizeof(dlm->live_nodes_map));
1150         spin_unlock(&dlm->spinlock);
1151
1152         if (ret)
1153                 mlog(0, "Node maps changed -- should restart\n");
1154
1155         return ret;
1156 }
1157
1158 static int dlm_try_to_join_domain(struct dlm_ctxt *dlm)
1159 {
1160         int status = 0, tmpstat, node;
1161         struct domain_join_ctxt *ctxt;
1162         enum dlm_query_join_response_code response = JOIN_DISALLOW;
1163
1164         mlog_entry("%p", dlm);
1165
1166         ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL);
1167         if (!ctxt) {
1168                 status = -ENOMEM;
1169                 mlog_errno(status);
1170                 goto bail;
1171         }
1172
1173         /* group sem locking should work for us here -- we're already
1174          * registered for heartbeat events so filling this should be
1175          * atomic wrt getting those handlers called. */
1176         o2hb_fill_node_map(dlm->live_nodes_map, sizeof(dlm->live_nodes_map));
1177
1178         spin_lock(&dlm->spinlock);
1179         memcpy(ctxt->live_map, dlm->live_nodes_map, sizeof(ctxt->live_map));
1180
1181         __dlm_set_joining_node(dlm, dlm->node_num);
1182
1183         spin_unlock(&dlm->spinlock);
1184
1185         node = -1;
1186         while ((node = find_next_bit(ctxt->live_map, O2NM_MAX_NODES,
1187                                      node + 1)) < O2NM_MAX_NODES) {
1188                 if (node == dlm->node_num)
1189                         continue;
1190
1191                 status = dlm_request_join(dlm, node, &response);
1192                 if (status < 0) {
1193                         mlog_errno(status);
1194                         goto bail;
1195                 }
1196
1197                 /* Ok, either we got a response or the node doesn't have a
1198                  * dlm up. */
1199                 if (response == JOIN_OK)
1200                         set_bit(node, ctxt->yes_resp_map);
1201
1202                 if (dlm_should_restart_join(dlm, ctxt, response)) {
1203                         status = -EAGAIN;
1204                         goto bail;
1205                 }
1206         }
1207
1208         mlog(0, "Yay, done querying nodes!\n");
1209
1210         /* Yay, everyone agree's we can join the domain. My domain is
1211          * comprised of all nodes who were put in the
1212          * yes_resp_map. Copy that into our domain map and send a join
1213          * assert message to clean up everyone elses state. */
1214         spin_lock(&dlm->spinlock);
1215         memcpy(dlm->domain_map, ctxt->yes_resp_map,
1216                sizeof(ctxt->yes_resp_map));
1217         set_bit(dlm->node_num, dlm->domain_map);
1218         spin_unlock(&dlm->spinlock);
1219
1220         dlm_send_join_asserts(dlm, ctxt->yes_resp_map);
1221
1222         /* Joined state *must* be set before the joining node
1223          * information, otherwise the query_join handler may read no
1224          * current joiner but a state of NEW and tell joining nodes
1225          * we're not in the domain. */
1226         spin_lock(&dlm_domain_lock);
1227         dlm->dlm_state = DLM_CTXT_JOINED;
1228         dlm->num_joins++;
1229         spin_unlock(&dlm_domain_lock);
1230
1231 bail:
1232         spin_lock(&dlm->spinlock);
1233         __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
1234         if (!status)
1235                 __dlm_print_nodes(dlm);
1236         spin_unlock(&dlm->spinlock);
1237
1238         if (ctxt) {
1239                 /* Do we need to send a cancel message to any nodes? */
1240                 if (status < 0) {
1241                         tmpstat = dlm_send_join_cancels(dlm,
1242                                                         ctxt->yes_resp_map,
1243                                                         sizeof(ctxt->yes_resp_map));
1244                         if (tmpstat < 0)
1245                                 mlog_errno(tmpstat);
1246                 }
1247                 kfree(ctxt);
1248         }
1249
1250         mlog(0, "returning %d\n", status);
1251         return status;
1252 }
1253
1254 static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm)
1255 {
1256         o2hb_unregister_callback(NULL, &dlm->dlm_hb_up);
1257         o2hb_unregister_callback(NULL, &dlm->dlm_hb_down);
1258         o2net_unregister_handler_list(&dlm->dlm_domain_handlers);
1259 }
1260
1261 static int dlm_register_domain_handlers(struct dlm_ctxt *dlm)
1262 {
1263         int status;
1264
1265         mlog(0, "registering handlers.\n");
1266
1267         o2hb_setup_callback(&dlm->dlm_hb_down, O2HB_NODE_DOWN_CB,
1268                             dlm_hb_node_down_cb, dlm, DLM_HB_NODE_DOWN_PRI);
1269         status = o2hb_register_callback(NULL, &dlm->dlm_hb_down);
1270         if (status)
1271                 goto bail;
1272
1273         o2hb_setup_callback(&dlm->dlm_hb_up, O2HB_NODE_UP_CB,
1274                             dlm_hb_node_up_cb, dlm, DLM_HB_NODE_UP_PRI);
1275         status = o2hb_register_callback(NULL, &dlm->dlm_hb_up);
1276         if (status)
1277                 goto bail;
1278
1279         status = o2net_register_handler(DLM_MASTER_REQUEST_MSG, dlm->key,
1280                                         sizeof(struct dlm_master_request),
1281                                         dlm_master_request_handler,
1282                                         dlm, NULL, &dlm->dlm_domain_handlers);
1283         if (status)
1284                 goto bail;
1285
1286         status = o2net_register_handler(DLM_ASSERT_MASTER_MSG, dlm->key,
1287                                         sizeof(struct dlm_assert_master),
1288                                         dlm_assert_master_handler,
1289                                         dlm, dlm_assert_master_post_handler,
1290                                         &dlm->dlm_domain_handlers);
1291         if (status)
1292                 goto bail;
1293
1294         status = o2net_register_handler(DLM_CREATE_LOCK_MSG, dlm->key,
1295                                         sizeof(struct dlm_create_lock),
1296                                         dlm_create_lock_handler,
1297                                         dlm, NULL, &dlm->dlm_domain_handlers);
1298         if (status)
1299                 goto bail;
1300
1301         status = o2net_register_handler(DLM_CONVERT_LOCK_MSG, dlm->key,
1302                                         DLM_CONVERT_LOCK_MAX_LEN,
1303                                         dlm_convert_lock_handler,
1304                                         dlm, NULL, &dlm->dlm_domain_handlers);
1305         if (status)
1306                 goto bail;
1307
1308         status = o2net_register_handler(DLM_UNLOCK_LOCK_MSG, dlm->key,
1309                                         DLM_UNLOCK_LOCK_MAX_LEN,
1310                                         dlm_unlock_lock_handler,
1311                                         dlm, NULL, &dlm->dlm_domain_handlers);
1312         if (status)
1313                 goto bail;
1314
1315         status = o2net_register_handler(DLM_PROXY_AST_MSG, dlm->key,
1316                                         DLM_PROXY_AST_MAX_LEN,
1317                                         dlm_proxy_ast_handler,
1318                                         dlm, NULL, &dlm->dlm_domain_handlers);
1319         if (status)
1320                 goto bail;
1321
1322         status = o2net_register_handler(DLM_EXIT_DOMAIN_MSG, dlm->key,
1323                                         sizeof(struct dlm_exit_domain),
1324                                         dlm_exit_domain_handler,
1325                                         dlm, NULL, &dlm->dlm_domain_handlers);
1326         if (status)
1327                 goto bail;
1328
1329         status = o2net_register_handler(DLM_DEREF_LOCKRES_MSG, dlm->key,
1330                                         sizeof(struct dlm_deref_lockres),
1331                                         dlm_deref_lockres_handler,
1332                                         dlm, NULL, &dlm->dlm_domain_handlers);
1333         if (status)
1334                 goto bail;
1335
1336         status = o2net_register_handler(DLM_MIGRATE_REQUEST_MSG, dlm->key,
1337                                         sizeof(struct dlm_migrate_request),
1338                                         dlm_migrate_request_handler,
1339                                         dlm, NULL, &dlm->dlm_domain_handlers);
1340         if (status)
1341                 goto bail;
1342
1343         status = o2net_register_handler(DLM_MIG_LOCKRES_MSG, dlm->key,
1344                                         DLM_MIG_LOCKRES_MAX_LEN,
1345                                         dlm_mig_lockres_handler,
1346                                         dlm, NULL, &dlm->dlm_domain_handlers);
1347         if (status)
1348                 goto bail;
1349
1350         status = o2net_register_handler(DLM_MASTER_REQUERY_MSG, dlm->key,
1351                                         sizeof(struct dlm_master_requery),
1352                                         dlm_master_requery_handler,
1353                                         dlm, NULL, &dlm->dlm_domain_handlers);
1354         if (status)
1355                 goto bail;
1356
1357         status = o2net_register_handler(DLM_LOCK_REQUEST_MSG, dlm->key,
1358                                         sizeof(struct dlm_lock_request),
1359                                         dlm_request_all_locks_handler,
1360                                         dlm, NULL, &dlm->dlm_domain_handlers);
1361         if (status)
1362                 goto bail;
1363
1364         status = o2net_register_handler(DLM_RECO_DATA_DONE_MSG, dlm->key,
1365                                         sizeof(struct dlm_reco_data_done),
1366                                         dlm_reco_data_done_handler,
1367                                         dlm, NULL, &dlm->dlm_domain_handlers);
1368         if (status)
1369                 goto bail;
1370
1371         status = o2net_register_handler(DLM_BEGIN_RECO_MSG, dlm->key,
1372                                         sizeof(struct dlm_begin_reco),
1373                                         dlm_begin_reco_handler,
1374                                         dlm, NULL, &dlm->dlm_domain_handlers);
1375         if (status)
1376                 goto bail;
1377
1378         status = o2net_register_handler(DLM_FINALIZE_RECO_MSG, dlm->key,
1379                                         sizeof(struct dlm_finalize_reco),
1380                                         dlm_finalize_reco_handler,
1381                                         dlm, NULL, &dlm->dlm_domain_handlers);
1382         if (status)
1383                 goto bail;
1384
1385 bail:
1386         if (status)
1387                 dlm_unregister_domain_handlers(dlm);
1388
1389         return status;
1390 }
1391
1392 static int dlm_join_domain(struct dlm_ctxt *dlm)
1393 {
1394         int status;
1395         unsigned int backoff;
1396         unsigned int total_backoff = 0;
1397
1398         BUG_ON(!dlm);
1399
1400         mlog(0, "Join domain %s\n", dlm->name);
1401
1402         status = dlm_register_domain_handlers(dlm);
1403         if (status) {
1404                 mlog_errno(status);
1405                 goto bail;
1406         }
1407
1408         status = dlm_launch_thread(dlm);
1409         if (status < 0) {
1410                 mlog_errno(status);
1411                 goto bail;
1412         }
1413
1414         status = dlm_launch_recovery_thread(dlm);
1415         if (status < 0) {
1416                 mlog_errno(status);
1417                 goto bail;
1418         }
1419
1420         dlm->dlm_worker = create_singlethread_workqueue("dlm_wq");
1421         if (!dlm->dlm_worker) {
1422                 status = -ENOMEM;
1423                 mlog_errno(status);
1424                 goto bail;
1425         }
1426
1427         do {
1428                 status = dlm_try_to_join_domain(dlm);
1429
1430                 /* If we're racing another node to the join, then we
1431                  * need to back off temporarily and let them
1432                  * complete. */
1433 #define DLM_JOIN_TIMEOUT_MSECS  90000
1434                 if (status == -EAGAIN) {
1435                         if (signal_pending(current)) {
1436                                 status = -ERESTARTSYS;
1437                                 goto bail;
1438                         }
1439
1440                         if (total_backoff >
1441                             msecs_to_jiffies(DLM_JOIN_TIMEOUT_MSECS)) {
1442                                 status = -ERESTARTSYS;
1443                                 mlog(ML_NOTICE, "Timed out joining dlm domain "
1444                                      "%s after %u msecs\n", dlm->name,
1445                                      jiffies_to_msecs(total_backoff));
1446                                 goto bail;
1447                         }
1448
1449                         /*
1450                          * <chip> After you!
1451                          * <dale> No, after you!
1452                          * <chip> I insist!
1453                          * <dale> But you first!
1454                          * ...
1455                          */
1456                         backoff = (unsigned int)(jiffies & 0x3);
1457                         backoff *= DLM_DOMAIN_BACKOFF_MS;
1458                         total_backoff += backoff;
1459                         mlog(0, "backoff %d\n", backoff);
1460                         msleep(backoff);
1461                 }
1462         } while (status == -EAGAIN);
1463
1464         if (status < 0) {
1465                 mlog_errno(status);
1466                 goto bail;
1467         }
1468
1469         status = 0;
1470 bail:
1471         wake_up(&dlm_domain_events);
1472
1473         if (status) {
1474                 dlm_unregister_domain_handlers(dlm);
1475                 dlm_complete_thread(dlm);
1476                 dlm_complete_recovery_thread(dlm);
1477                 dlm_destroy_dlm_worker(dlm);
1478         }
1479
1480         return status;
1481 }
1482
1483 static struct dlm_ctxt *dlm_alloc_ctxt(const char *domain,
1484                                 u32 key)
1485 {
1486         int i;
1487         struct dlm_ctxt *dlm = NULL;
1488
1489         dlm = kzalloc(sizeof(*dlm), GFP_KERNEL);
1490         if (!dlm) {
1491                 mlog_errno(-ENOMEM);
1492                 goto leave;
1493         }
1494
1495         dlm->name = kmalloc(strlen(domain) + 1, GFP_KERNEL);
1496         if (dlm->name == NULL) {
1497                 mlog_errno(-ENOMEM);
1498                 kfree(dlm);
1499                 dlm = NULL;
1500                 goto leave;
1501         }
1502
1503         dlm->lockres_hash = (struct hlist_head **)dlm_alloc_pagevec(DLM_HASH_PAGES);
1504         if (!dlm->lockres_hash) {
1505                 mlog_errno(-ENOMEM);
1506                 kfree(dlm->name);
1507                 kfree(dlm);
1508                 dlm = NULL;
1509                 goto leave;
1510         }
1511
1512         for (i = 0; i < DLM_HASH_BUCKETS; i++)
1513                 INIT_HLIST_HEAD(dlm_lockres_hash(dlm, i));
1514
1515         strcpy(dlm->name, domain);
1516         dlm->key = key;
1517         dlm->node_num = o2nm_this_node();
1518
1519         spin_lock_init(&dlm->spinlock);
1520         spin_lock_init(&dlm->master_lock);
1521         spin_lock_init(&dlm->ast_lock);
1522         INIT_LIST_HEAD(&dlm->list);
1523         INIT_LIST_HEAD(&dlm->dirty_list);
1524         INIT_LIST_HEAD(&dlm->reco.resources);
1525         INIT_LIST_HEAD(&dlm->reco.received);
1526         INIT_LIST_HEAD(&dlm->reco.node_data);
1527         INIT_LIST_HEAD(&dlm->purge_list);
1528         INIT_LIST_HEAD(&dlm->dlm_domain_handlers);
1529         dlm->reco.state = 0;
1530
1531         INIT_LIST_HEAD(&dlm->pending_asts);
1532         INIT_LIST_HEAD(&dlm->pending_basts);
1533
1534         mlog(0, "dlm->recovery_map=%p, &(dlm->recovery_map[0])=%p\n",
1535                   dlm->recovery_map, &(dlm->recovery_map[0]));
1536
1537         memset(dlm->recovery_map, 0, sizeof(dlm->recovery_map));
1538         memset(dlm->live_nodes_map, 0, sizeof(dlm->live_nodes_map));
1539         memset(dlm->domain_map, 0, sizeof(dlm->domain_map));
1540
1541         dlm->dlm_thread_task = NULL;
1542         dlm->dlm_reco_thread_task = NULL;
1543         dlm->dlm_worker = NULL;
1544         init_waitqueue_head(&dlm->dlm_thread_wq);
1545         init_waitqueue_head(&dlm->dlm_reco_thread_wq);
1546         init_waitqueue_head(&dlm->reco.event);
1547         init_waitqueue_head(&dlm->ast_wq);
1548         init_waitqueue_head(&dlm->migration_wq);
1549         INIT_LIST_HEAD(&dlm->master_list);
1550         INIT_LIST_HEAD(&dlm->mle_hb_events);
1551
1552         dlm->joining_node = DLM_LOCK_RES_OWNER_UNKNOWN;
1553         init_waitqueue_head(&dlm->dlm_join_events);
1554
1555         dlm->reco.new_master = O2NM_INVALID_NODE_NUM;
1556         dlm->reco.dead_node = O2NM_INVALID_NODE_NUM;
1557         atomic_set(&dlm->local_resources, 0);
1558         atomic_set(&dlm->remote_resources, 0);
1559         atomic_set(&dlm->unknown_resources, 0);
1560
1561         spin_lock_init(&dlm->work_lock);
1562         INIT_LIST_HEAD(&dlm->work_list);
1563         INIT_WORK(&dlm->dispatched_work, dlm_dispatch_work);
1564
1565         kref_init(&dlm->dlm_refs);
1566         dlm->dlm_state = DLM_CTXT_NEW;
1567
1568         INIT_LIST_HEAD(&dlm->dlm_eviction_callbacks);
1569
1570         mlog(0, "context init: refcount %u\n",
1571                   atomic_read(&dlm->dlm_refs.refcount));
1572
1573 leave:
1574         return dlm;
1575 }
1576
1577 /*
1578  * Compare a requested locking protocol version against the current one.
1579  *
1580  * If the major numbers are different, they are incompatible.
1581  * If the current minor is greater than the request, they are incompatible.
1582  * If the current minor is less than or equal to the request, they are
1583  * compatible, and the requester should run at the current minor version.
1584  */
1585 static int dlm_protocol_compare(struct dlm_protocol_version *existing,
1586                                 struct dlm_protocol_version *request)
1587 {
1588         if (existing->pv_major != request->pv_major)
1589                 return 1;
1590
1591         if (existing->pv_minor > request->pv_minor)
1592                 return 1;
1593
1594         if (existing->pv_minor < request->pv_minor)
1595                 request->pv_minor = existing->pv_minor;
1596
1597         return 0;
1598 }
1599
1600 /*
1601  * dlm_register_domain: one-time setup per "domain".
1602  *
1603  * The filesystem passes in the requested locking version via proto.
1604  * If registration was successful, proto will contain the negotiated
1605  * locking protocol.
1606  */
1607 struct dlm_ctxt * dlm_register_domain(const char *domain,
1608                                u32 key,
1609                                struct dlm_protocol_version *fs_proto)
1610 {
1611         int ret;
1612         struct dlm_ctxt *dlm = NULL;
1613         struct dlm_ctxt *new_ctxt = NULL;
1614
1615         if (strlen(domain) > O2NM_MAX_NAME_LEN) {
1616                 ret = -ENAMETOOLONG;
1617                 mlog(ML_ERROR, "domain name length too long\n");
1618                 goto leave;
1619         }
1620
1621         if (!o2hb_check_local_node_heartbeating()) {
1622                 mlog(ML_ERROR, "the local node has not been configured, or is "
1623                      "not heartbeating\n");
1624                 ret = -EPROTO;
1625                 goto leave;
1626         }
1627
1628         mlog(0, "register called for domain \"%s\"\n", domain);
1629
1630 retry:
1631         dlm = NULL;
1632         if (signal_pending(current)) {
1633                 ret = -ERESTARTSYS;
1634                 mlog_errno(ret);
1635                 goto leave;
1636         }
1637
1638         spin_lock(&dlm_domain_lock);
1639
1640         dlm = __dlm_lookup_domain(domain);
1641         if (dlm) {
1642                 if (dlm->dlm_state != DLM_CTXT_JOINED) {
1643                         spin_unlock(&dlm_domain_lock);
1644
1645                         mlog(0, "This ctxt is not joined yet!\n");
1646                         wait_event_interruptible(dlm_domain_events,
1647                                                  dlm_wait_on_domain_helper(
1648                                                          domain));
1649                         goto retry;
1650                 }
1651
1652                 if (dlm_protocol_compare(&dlm->fs_locking_proto, fs_proto)) {
1653                         mlog(ML_ERROR,
1654                              "Requested locking protocol version is not "
1655                              "compatible with already registered domain "
1656                              "\"%s\"\n", domain);
1657                         ret = -EPROTO;
1658                         goto leave;
1659                 }
1660
1661                 __dlm_get(dlm);
1662                 dlm->num_joins++;
1663
1664                 spin_unlock(&dlm_domain_lock);
1665
1666                 ret = 0;
1667                 goto leave;
1668         }
1669
1670         /* doesn't exist */
1671         if (!new_ctxt) {
1672                 spin_unlock(&dlm_domain_lock);
1673
1674                 new_ctxt = dlm_alloc_ctxt(domain, key);
1675                 if (new_ctxt)
1676                         goto retry;
1677
1678                 ret = -ENOMEM;
1679                 mlog_errno(ret);
1680                 goto leave;
1681         }
1682
1683         /* a little variable switch-a-roo here... */
1684         dlm = new_ctxt;
1685         new_ctxt = NULL;
1686
1687         /* add the new domain */
1688         list_add_tail(&dlm->list, &dlm_domains);
1689         spin_unlock(&dlm_domain_lock);
1690
1691         /*
1692          * Pass the locking protocol version into the join.  If the join
1693          * succeeds, it will have the negotiated protocol set.
1694          */
1695         dlm->dlm_locking_proto = dlm_protocol;
1696         dlm->fs_locking_proto = *fs_proto;
1697
1698         ret = dlm_join_domain(dlm);
1699         if (ret) {
1700                 mlog_errno(ret);
1701                 dlm_put(dlm);
1702                 goto leave;
1703         }
1704
1705         /* Tell the caller what locking protocol we negotiated */
1706         *fs_proto = dlm->fs_locking_proto;
1707
1708         ret = 0;
1709 leave:
1710         if (new_ctxt)
1711                 dlm_free_ctxt_mem(new_ctxt);
1712
1713         if (ret < 0)
1714                 dlm = ERR_PTR(ret);
1715
1716         return dlm;
1717 }
1718 EXPORT_SYMBOL_GPL(dlm_register_domain);
1719
1720 static LIST_HEAD(dlm_join_handlers);
1721
1722 static void dlm_unregister_net_handlers(void)
1723 {
1724         o2net_unregister_handler_list(&dlm_join_handlers);
1725 }
1726
1727 static int dlm_register_net_handlers(void)
1728 {
1729         int status = 0;
1730
1731         status = o2net_register_handler(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY,
1732                                         sizeof(struct dlm_query_join_request),
1733                                         dlm_query_join_handler,
1734                                         NULL, NULL, &dlm_join_handlers);
1735         if (status)
1736                 goto bail;
1737
1738         status = o2net_register_handler(DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
1739                                         sizeof(struct dlm_assert_joined),
1740                                         dlm_assert_joined_handler,
1741                                         NULL, NULL, &dlm_join_handlers);
1742         if (status)
1743                 goto bail;
1744
1745         status = o2net_register_handler(DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
1746                                         sizeof(struct dlm_cancel_join),
1747                                         dlm_cancel_join_handler,
1748                                         NULL, NULL, &dlm_join_handlers);
1749
1750 bail:
1751         if (status < 0)
1752                 dlm_unregister_net_handlers();
1753
1754         return status;
1755 }
1756
1757 /* Domain eviction callback handling.
1758  *
1759  * The file system requires notification of node death *before* the
1760  * dlm completes it's recovery work, otherwise it may be able to
1761  * acquire locks on resources requiring recovery. Since the dlm can
1762  * evict a node from it's domain *before* heartbeat fires, a similar
1763  * mechanism is required. */
1764
1765 /* Eviction is not expected to happen often, so a per-domain lock is
1766  * not necessary. Eviction callbacks are allowed to sleep for short
1767  * periods of time. */
1768 static DECLARE_RWSEM(dlm_callback_sem);
1769
1770 void dlm_fire_domain_eviction_callbacks(struct dlm_ctxt *dlm,
1771                                         int node_num)
1772 {
1773         struct list_head *iter;
1774         struct dlm_eviction_cb *cb;
1775
1776         down_read(&dlm_callback_sem);
1777         list_for_each(iter, &dlm->dlm_eviction_callbacks) {
1778                 cb = list_entry(iter, struct dlm_eviction_cb, ec_item);
1779
1780                 cb->ec_func(node_num, cb->ec_data);
1781         }
1782         up_read(&dlm_callback_sem);
1783 }
1784
1785 void dlm_setup_eviction_cb(struct dlm_eviction_cb *cb,
1786                            dlm_eviction_func *f,
1787                            void *data)
1788 {
1789         INIT_LIST_HEAD(&cb->ec_item);
1790         cb->ec_func = f;
1791         cb->ec_data = data;
1792 }
1793 EXPORT_SYMBOL_GPL(dlm_setup_eviction_cb);
1794
1795 void dlm_register_eviction_cb(struct dlm_ctxt *dlm,
1796                               struct dlm_eviction_cb *cb)
1797 {
1798         down_write(&dlm_callback_sem);
1799         list_add_tail(&cb->ec_item, &dlm->dlm_eviction_callbacks);
1800         up_write(&dlm_callback_sem);
1801 }
1802 EXPORT_SYMBOL_GPL(dlm_register_eviction_cb);
1803
1804 void dlm_unregister_eviction_cb(struct dlm_eviction_cb *cb)
1805 {
1806         down_write(&dlm_callback_sem);
1807         list_del_init(&cb->ec_item);
1808         up_write(&dlm_callback_sem);
1809 }
1810 EXPORT_SYMBOL_GPL(dlm_unregister_eviction_cb);
1811
1812 static int __init dlm_init(void)
1813 {
1814         int status;
1815
1816         dlm_print_version();
1817
1818         status = dlm_init_mle_cache();
1819         if (status)
1820                 return -1;
1821
1822         status = dlm_register_net_handlers();
1823         if (status) {
1824                 dlm_destroy_mle_cache();
1825                 return -1;
1826         }
1827
1828         return 0;
1829 }
1830
1831 static void __exit dlm_exit (void)
1832 {
1833         dlm_unregister_net_handlers();
1834         dlm_destroy_mle_cache();
1835 }
1836
1837 MODULE_AUTHOR("Oracle");
1838 MODULE_LICENSE("GPL");
1839
1840 module_init(dlm_init);
1841 module_exit(dlm_exit);