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TOMOYO Linux Cross Reference
Linux/fs/ocfs2/dlm/dlmdomain.c

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  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/init.h>
 32 #include <linux/spinlock.h>
 33 #include <linux/delay.h>
 34 #include <linux/err.h>
 35 #include <linux/debugfs.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 #include "dlmdomain.h"
 44 #include "dlmdebug.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  * New in version 1.1:
133  *      - Message DLM_QUERY_REGION added to support global heartbeat
134  *      - Message DLM_QUERY_NODEINFO added to allow online node removes
135  * New in version 1.2:
136  *      - Message DLM_BEGIN_EXIT_DOMAIN_MSG added to mark start of exit domain
137  */
138 static const struct dlm_protocol_version dlm_protocol = {
139         .pv_major = 1,
140         .pv_minor = 2,
141 };
142 
143 #define DLM_DOMAIN_BACKOFF_MS 200
144 
145 static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
146                                   void **ret_data);
147 static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data,
148                                      void **ret_data);
149 static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data,
150                                    void **ret_data);
151 static int dlm_query_region_handler(struct o2net_msg *msg, u32 len,
152                                     void *data, void **ret_data);
153 static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data,
154                                    void **ret_data);
155 static int dlm_protocol_compare(struct dlm_protocol_version *existing,
156                                 struct dlm_protocol_version *request);
157 
158 static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm);
159 
160 void __dlm_unhash_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
161 {
162         if (hlist_unhashed(&res->hash_node))
163                 return;
164 
165         mlog(0, "%s: Unhash res %.*s\n", dlm->name, res->lockname.len,
166              res->lockname.name);
167         hlist_del_init(&res->hash_node);
168         dlm_lockres_put(res);
169 }
170 
171 void __dlm_insert_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
172 {
173         struct hlist_head *bucket;
174         struct qstr *q;
175 
176         assert_spin_locked(&dlm->spinlock);
177 
178         q = &res->lockname;
179         bucket = dlm_lockres_hash(dlm, q->hash);
180 
181         /* get a reference for our hashtable */
182         dlm_lockres_get(res);
183 
184         hlist_add_head(&res->hash_node, bucket);
185 
186         mlog(0, "%s: Hash res %.*s\n", dlm->name, res->lockname.len,
187              res->lockname.name);
188 }
189 
190 struct dlm_lock_resource * __dlm_lookup_lockres_full(struct dlm_ctxt *dlm,
191                                                      const char *name,
192                                                      unsigned int len,
193                                                      unsigned int hash)
194 {
195         struct hlist_head *bucket;
196         struct dlm_lock_resource *res;
197 
198         mlog(0, "%.*s\n", len, name);
199 
200         assert_spin_locked(&dlm->spinlock);
201 
202         bucket = dlm_lockres_hash(dlm, hash);
203 
204         hlist_for_each_entry(res, bucket, hash_node) {
205                 if (res->lockname.name[0] != name[0])
206                         continue;
207                 if (unlikely(res->lockname.len != len))
208                         continue;
209                 if (memcmp(res->lockname.name + 1, name + 1, len - 1))
210                         continue;
211                 dlm_lockres_get(res);
212                 return res;
213         }
214         return NULL;
215 }
216 
217 /* intended to be called by functions which do not care about lock
218  * resources which are being purged (most net _handler functions).
219  * this will return NULL for any lock resource which is found but
220  * currently in the process of dropping its mastery reference.
221  * use __dlm_lookup_lockres_full when you need the lock resource
222  * regardless (e.g. dlm_get_lock_resource) */
223 struct dlm_lock_resource * __dlm_lookup_lockres(struct dlm_ctxt *dlm,
224                                                 const char *name,
225                                                 unsigned int len,
226                                                 unsigned int hash)
227 {
228         struct dlm_lock_resource *res = NULL;
229 
230         mlog(0, "%.*s\n", len, name);
231 
232         assert_spin_locked(&dlm->spinlock);
233 
234         res = __dlm_lookup_lockres_full(dlm, name, len, hash);
235         if (res) {
236                 spin_lock(&res->spinlock);
237                 if (res->state & DLM_LOCK_RES_DROPPING_REF) {
238                         spin_unlock(&res->spinlock);
239                         dlm_lockres_put(res);
240                         return NULL;
241                 }
242                 spin_unlock(&res->spinlock);
243         }
244 
245         return res;
246 }
247 
248 struct dlm_lock_resource * dlm_lookup_lockres(struct dlm_ctxt *dlm,
249                                     const char *name,
250                                     unsigned int len)
251 {
252         struct dlm_lock_resource *res;
253         unsigned int hash = dlm_lockid_hash(name, len);
254 
255         spin_lock(&dlm->spinlock);
256         res = __dlm_lookup_lockres(dlm, name, len, hash);
257         spin_unlock(&dlm->spinlock);
258         return res;
259 }
260 
261 static struct dlm_ctxt * __dlm_lookup_domain_full(const char *domain, int len)
262 {
263         struct dlm_ctxt *tmp;
264 
265         assert_spin_locked(&dlm_domain_lock);
266 
267         /* tmp->name here is always NULL terminated,
268          * but domain may not be! */
269         list_for_each_entry(tmp, &dlm_domains, list) {
270                 if (strlen(tmp->name) == len &&
271                     memcmp(tmp->name, domain, len)==0)
272                         return tmp;
273         }
274 
275         return NULL;
276 }
277 
278 /* For null terminated domain strings ONLY */
279 static struct dlm_ctxt * __dlm_lookup_domain(const char *domain)
280 {
281         assert_spin_locked(&dlm_domain_lock);
282 
283         return __dlm_lookup_domain_full(domain, strlen(domain));
284 }
285 
286 
287 /* returns true on one of two conditions:
288  * 1) the domain does not exist
289  * 2) the domain exists and it's state is "joined" */
290 static int dlm_wait_on_domain_helper(const char *domain)
291 {
292         int ret = 0;
293         struct dlm_ctxt *tmp = NULL;
294 
295         spin_lock(&dlm_domain_lock);
296 
297         tmp = __dlm_lookup_domain(domain);
298         if (!tmp)
299                 ret = 1;
300         else if (tmp->dlm_state == DLM_CTXT_JOINED)
301                 ret = 1;
302 
303         spin_unlock(&dlm_domain_lock);
304         return ret;
305 }
306 
307 static void dlm_free_ctxt_mem(struct dlm_ctxt *dlm)
308 {
309         dlm_destroy_debugfs_subroot(dlm);
310 
311         if (dlm->lockres_hash)
312                 dlm_free_pagevec((void **)dlm->lockres_hash, DLM_HASH_PAGES);
313 
314         if (dlm->master_hash)
315                 dlm_free_pagevec((void **)dlm->master_hash, DLM_HASH_PAGES);
316 
317         kfree(dlm->name);
318         kfree(dlm);
319 }
320 
321 /* A little strange - this function will be called while holding
322  * dlm_domain_lock and is expected to be holding it on the way out. We
323  * will however drop and reacquire it multiple times */
324 static void dlm_ctxt_release(struct kref *kref)
325 {
326         struct dlm_ctxt *dlm;
327 
328         dlm = container_of(kref, struct dlm_ctxt, dlm_refs);
329 
330         BUG_ON(dlm->num_joins);
331         BUG_ON(dlm->dlm_state == DLM_CTXT_JOINED);
332 
333         /* we may still be in the list if we hit an error during join. */
334         list_del_init(&dlm->list);
335 
336         spin_unlock(&dlm_domain_lock);
337 
338         mlog(0, "freeing memory from domain %s\n", dlm->name);
339 
340         wake_up(&dlm_domain_events);
341 
342         dlm_free_ctxt_mem(dlm);
343 
344         spin_lock(&dlm_domain_lock);
345 }
346 
347 void dlm_put(struct dlm_ctxt *dlm)
348 {
349         spin_lock(&dlm_domain_lock);
350         kref_put(&dlm->dlm_refs, dlm_ctxt_release);
351         spin_unlock(&dlm_domain_lock);
352 }
353 
354 static void __dlm_get(struct dlm_ctxt *dlm)
355 {
356         kref_get(&dlm->dlm_refs);
357 }
358 
359 /* given a questionable reference to a dlm object, gets a reference if
360  * it can find it in the list, otherwise returns NULL in which case
361  * you shouldn't trust your pointer. */
362 struct dlm_ctxt *dlm_grab(struct dlm_ctxt *dlm)
363 {
364         struct dlm_ctxt *target;
365         struct dlm_ctxt *ret = NULL;
366 
367         spin_lock(&dlm_domain_lock);
368 
369         list_for_each_entry(target, &dlm_domains, list) {
370                 if (target == dlm) {
371                         __dlm_get(target);
372                         ret = target;
373                         break;
374                 }
375         }
376 
377         spin_unlock(&dlm_domain_lock);
378 
379         return ret;
380 }
381 
382 int dlm_domain_fully_joined(struct dlm_ctxt *dlm)
383 {
384         int ret;
385 
386         spin_lock(&dlm_domain_lock);
387         ret = (dlm->dlm_state == DLM_CTXT_JOINED) ||
388                 (dlm->dlm_state == DLM_CTXT_IN_SHUTDOWN);
389         spin_unlock(&dlm_domain_lock);
390 
391         return ret;
392 }
393 
394 static void dlm_destroy_dlm_worker(struct dlm_ctxt *dlm)
395 {
396         if (dlm->dlm_worker) {
397                 flush_workqueue(dlm->dlm_worker);
398                 destroy_workqueue(dlm->dlm_worker);
399                 dlm->dlm_worker = NULL;
400         }
401 }
402 
403 static void dlm_complete_dlm_shutdown(struct dlm_ctxt *dlm)
404 {
405         dlm_unregister_domain_handlers(dlm);
406         dlm_debug_shutdown(dlm);
407         dlm_complete_thread(dlm);
408         dlm_complete_recovery_thread(dlm);
409         dlm_destroy_dlm_worker(dlm);
410 
411         /* We've left the domain. Now we can take ourselves out of the
412          * list and allow the kref stuff to help us free the
413          * memory. */
414         spin_lock(&dlm_domain_lock);
415         list_del_init(&dlm->list);
416         spin_unlock(&dlm_domain_lock);
417 
418         /* Wake up anyone waiting for us to remove this domain */
419         wake_up(&dlm_domain_events);
420 }
421 
422 static int dlm_migrate_all_locks(struct dlm_ctxt *dlm)
423 {
424         int i, num, n, ret = 0;
425         struct dlm_lock_resource *res;
426         struct hlist_node *iter;
427         struct hlist_head *bucket;
428         int dropped;
429 
430         mlog(0, "Migrating locks from domain %s\n", dlm->name);
431 
432         num = 0;
433         spin_lock(&dlm->spinlock);
434         for (i = 0; i < DLM_HASH_BUCKETS; i++) {
435 redo_bucket:
436                 n = 0;
437                 bucket = dlm_lockres_hash(dlm, i);
438                 iter = bucket->first;
439                 while (iter) {
440                         n++;
441                         res = hlist_entry(iter, struct dlm_lock_resource,
442                                           hash_node);
443                         dlm_lockres_get(res);
444                         /* migrate, if necessary.  this will drop the dlm
445                          * spinlock and retake it if it does migration. */
446                         dropped = dlm_empty_lockres(dlm, res);
447 
448                         spin_lock(&res->spinlock);
449                         if (dropped)
450                                 __dlm_lockres_calc_usage(dlm, res);
451                         else
452                                 iter = res->hash_node.next;
453                         spin_unlock(&res->spinlock);
454 
455                         dlm_lockres_put(res);
456 
457                         if (dropped) {
458                                 cond_resched_lock(&dlm->spinlock);
459                                 goto redo_bucket;
460                         }
461                 }
462                 cond_resched_lock(&dlm->spinlock);
463                 num += n;
464         }
465         spin_unlock(&dlm->spinlock);
466         wake_up(&dlm->dlm_thread_wq);
467 
468         /* let the dlm thread take care of purging, keep scanning until
469          * nothing remains in the hash */
470         if (num) {
471                 mlog(0, "%s: %d lock resources in hash last pass\n",
472                      dlm->name, num);
473                 ret = -EAGAIN;
474         }
475         mlog(0, "DONE Migrating locks from domain %s\n", dlm->name);
476         return ret;
477 }
478 
479 static int dlm_no_joining_node(struct dlm_ctxt *dlm)
480 {
481         int ret;
482 
483         spin_lock(&dlm->spinlock);
484         ret = dlm->joining_node == DLM_LOCK_RES_OWNER_UNKNOWN;
485         spin_unlock(&dlm->spinlock);
486 
487         return ret;
488 }
489 
490 static int dlm_begin_exit_domain_handler(struct o2net_msg *msg, u32 len,
491                                          void *data, void **ret_data)
492 {
493         struct dlm_ctxt *dlm = data;
494         unsigned int node;
495         struct dlm_exit_domain *exit_msg = (struct dlm_exit_domain *) msg->buf;
496 
497         if (!dlm_grab(dlm))
498                 return 0;
499 
500         node = exit_msg->node_idx;
501         mlog(0, "%s: Node %u sent a begin exit domain message\n", dlm->name, node);
502 
503         spin_lock(&dlm->spinlock);
504         set_bit(node, dlm->exit_domain_map);
505         spin_unlock(&dlm->spinlock);
506 
507         dlm_put(dlm);
508 
509         return 0;
510 }
511 
512 static void dlm_mark_domain_leaving(struct dlm_ctxt *dlm)
513 {
514         /* Yikes, a double spinlock! I need domain_lock for the dlm
515          * state and the dlm spinlock for join state... Sorry! */
516 again:
517         spin_lock(&dlm_domain_lock);
518         spin_lock(&dlm->spinlock);
519 
520         if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
521                 mlog(0, "Node %d is joining, we wait on it.\n",
522                           dlm->joining_node);
523                 spin_unlock(&dlm->spinlock);
524                 spin_unlock(&dlm_domain_lock);
525 
526                 wait_event(dlm->dlm_join_events, dlm_no_joining_node(dlm));
527                 goto again;
528         }
529 
530         dlm->dlm_state = DLM_CTXT_LEAVING;
531         spin_unlock(&dlm->spinlock);
532         spin_unlock(&dlm_domain_lock);
533 }
534 
535 static void __dlm_print_nodes(struct dlm_ctxt *dlm)
536 {
537         int node = -1, num = 0;
538 
539         assert_spin_locked(&dlm->spinlock);
540 
541         printk("( ");
542         while ((node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES,
543                                      node + 1)) < O2NM_MAX_NODES) {
544                 printk("%d ", node);
545                 ++num;
546         }
547         printk(") %u nodes\n", num);
548 }
549 
550 static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data,
551                                    void **ret_data)
552 {
553         struct dlm_ctxt *dlm = data;
554         unsigned int node;
555         struct dlm_exit_domain *exit_msg = (struct dlm_exit_domain *) msg->buf;
556 
557         mlog(0, "%p %u %p", msg, len, data);
558 
559         if (!dlm_grab(dlm))
560                 return 0;
561 
562         node = exit_msg->node_idx;
563 
564         spin_lock(&dlm->spinlock);
565         clear_bit(node, dlm->domain_map);
566         clear_bit(node, dlm->exit_domain_map);
567         printk(KERN_NOTICE "o2dlm: Node %u leaves domain %s ", node, dlm->name);
568         __dlm_print_nodes(dlm);
569 
570         /* notify anything attached to the heartbeat events */
571         dlm_hb_event_notify_attached(dlm, node, 0);
572 
573         spin_unlock(&dlm->spinlock);
574 
575         dlm_put(dlm);
576 
577         return 0;
578 }
579 
580 static int dlm_send_one_domain_exit(struct dlm_ctxt *dlm, u32 msg_type,
581                                     unsigned int node)
582 {
583         int status;
584         struct dlm_exit_domain leave_msg;
585 
586         mlog(0, "%s: Sending domain exit message %u to node %u\n", dlm->name,
587              msg_type, node);
588 
589         memset(&leave_msg, 0, sizeof(leave_msg));
590         leave_msg.node_idx = dlm->node_num;
591 
592         status = o2net_send_message(msg_type, dlm->key, &leave_msg,
593                                     sizeof(leave_msg), node, NULL);
594         if (status < 0)
595                 mlog(ML_ERROR, "Error %d sending domain exit message %u "
596                      "to node %u on domain %s\n", status, msg_type, node,
597                      dlm->name);
598 
599         return status;
600 }
601 
602 static void dlm_begin_exit_domain(struct dlm_ctxt *dlm)
603 {
604         int node = -1;
605 
606         /* Support for begin exit domain was added in 1.2 */
607         if (dlm->dlm_locking_proto.pv_major == 1 &&
608             dlm->dlm_locking_proto.pv_minor < 2)
609                 return;
610 
611         /*
612          * Unlike DLM_EXIT_DOMAIN_MSG, DLM_BEGIN_EXIT_DOMAIN_MSG is purely
613          * informational. Meaning if a node does not receive the message,
614          * so be it.
615          */
616         spin_lock(&dlm->spinlock);
617         while (1) {
618                 node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES, node + 1);
619                 if (node >= O2NM_MAX_NODES)
620                         break;
621                 if (node == dlm->node_num)
622                         continue;
623 
624                 spin_unlock(&dlm->spinlock);
625                 dlm_send_one_domain_exit(dlm, DLM_BEGIN_EXIT_DOMAIN_MSG, node);
626                 spin_lock(&dlm->spinlock);
627         }
628         spin_unlock(&dlm->spinlock);
629 }
630 
631 static void dlm_leave_domain(struct dlm_ctxt *dlm)
632 {
633         int node, clear_node, status;
634 
635         /* At this point we've migrated away all our locks and won't
636          * accept mastership of new ones. The dlm is responsible for
637          * almost nothing now. We make sure not to confuse any joining
638          * nodes and then commence shutdown procedure. */
639 
640         spin_lock(&dlm->spinlock);
641         /* Clear ourselves from the domain map */
642         clear_bit(dlm->node_num, dlm->domain_map);
643         while ((node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES,
644                                      0)) < O2NM_MAX_NODES) {
645                 /* Drop the dlm spinlock. This is safe wrt the domain_map.
646                  * -nodes cannot be added now as the
647                  *   query_join_handlers knows to respond with OK_NO_MAP
648                  * -we catch the right network errors if a node is
649                  *   removed from the map while we're sending him the
650                  *   exit message. */
651                 spin_unlock(&dlm->spinlock);
652 
653                 clear_node = 1;
654 
655                 status = dlm_send_one_domain_exit(dlm, DLM_EXIT_DOMAIN_MSG,
656                                                   node);
657                 if (status < 0 &&
658                     status != -ENOPROTOOPT &&
659                     status != -ENOTCONN) {
660                         mlog(ML_NOTICE, "Error %d sending domain exit message "
661                              "to node %d\n", status, node);
662 
663                         /* Not sure what to do here but lets sleep for
664                          * a bit in case this was a transient
665                          * error... */
666                         msleep(DLM_DOMAIN_BACKOFF_MS);
667                         clear_node = 0;
668                 }
669 
670                 spin_lock(&dlm->spinlock);
671                 /* If we're not clearing the node bit then we intend
672                  * to loop back around to try again. */
673                 if (clear_node)
674                         clear_bit(node, dlm->domain_map);
675         }
676         spin_unlock(&dlm->spinlock);
677 }
678 
679 int dlm_joined(struct dlm_ctxt *dlm)
680 {
681         int ret = 0;
682 
683         spin_lock(&dlm_domain_lock);
684 
685         if (dlm->dlm_state == DLM_CTXT_JOINED)
686                 ret = 1;
687 
688         spin_unlock(&dlm_domain_lock);
689 
690         return ret;
691 }
692 
693 int dlm_shutting_down(struct dlm_ctxt *dlm)
694 {
695         int ret = 0;
696 
697         spin_lock(&dlm_domain_lock);
698 
699         if (dlm->dlm_state == DLM_CTXT_IN_SHUTDOWN)
700                 ret = 1;
701 
702         spin_unlock(&dlm_domain_lock);
703 
704         return ret;
705 }
706 
707 void dlm_unregister_domain(struct dlm_ctxt *dlm)
708 {
709         int leave = 0;
710         struct dlm_lock_resource *res;
711 
712         spin_lock(&dlm_domain_lock);
713         BUG_ON(dlm->dlm_state != DLM_CTXT_JOINED);
714         BUG_ON(!dlm->num_joins);
715 
716         dlm->num_joins--;
717         if (!dlm->num_joins) {
718                 /* We mark it "in shutdown" now so new register
719                  * requests wait until we've completely left the
720                  * domain. Don't use DLM_CTXT_LEAVING yet as we still
721                  * want new domain joins to communicate with us at
722                  * least until we've completed migration of our
723                  * resources. */
724                 dlm->dlm_state = DLM_CTXT_IN_SHUTDOWN;
725                 leave = 1;
726         }
727         spin_unlock(&dlm_domain_lock);
728 
729         if (leave) {
730                 mlog(0, "shutting down domain %s\n", dlm->name);
731                 dlm_begin_exit_domain(dlm);
732 
733                 /* We changed dlm state, notify the thread */
734                 dlm_kick_thread(dlm, NULL);
735 
736                 while (dlm_migrate_all_locks(dlm)) {
737                         /* Give dlm_thread time to purge the lockres' */
738                         msleep(500);
739                         mlog(0, "%s: more migration to do\n", dlm->name);
740                 }
741 
742                 /* This list should be empty. If not, print remaining lockres */
743                 if (!list_empty(&dlm->tracking_list)) {
744                         mlog(ML_ERROR, "Following lockres' are still on the "
745                              "tracking list:\n");
746                         list_for_each_entry(res, &dlm->tracking_list, tracking)
747                                 dlm_print_one_lock_resource(res);
748                 }
749 
750                 dlm_mark_domain_leaving(dlm);
751                 dlm_leave_domain(dlm);
752                 printk(KERN_NOTICE "o2dlm: Leaving domain %s\n", dlm->name);
753                 dlm_force_free_mles(dlm);
754                 dlm_complete_dlm_shutdown(dlm);
755         }
756         dlm_put(dlm);
757 }
758 EXPORT_SYMBOL_GPL(dlm_unregister_domain);
759 
760 static int dlm_query_join_proto_check(char *proto_type, int node,
761                                       struct dlm_protocol_version *ours,
762                                       struct dlm_protocol_version *request)
763 {
764         int rc;
765         struct dlm_protocol_version proto = *request;
766 
767         if (!dlm_protocol_compare(ours, &proto)) {
768                 mlog(0,
769                      "node %u wanted to join with %s locking protocol "
770                      "%u.%u, we respond with %u.%u\n",
771                      node, proto_type,
772                      request->pv_major,
773                      request->pv_minor,
774                      proto.pv_major, proto.pv_minor);
775                 request->pv_minor = proto.pv_minor;
776                 rc = 0;
777         } else {
778                 mlog(ML_NOTICE,
779                      "Node %u wanted to join with %s locking "
780                      "protocol %u.%u, but we have %u.%u, disallowing\n",
781                      node, proto_type,
782                      request->pv_major,
783                      request->pv_minor,
784                      ours->pv_major,
785                      ours->pv_minor);
786                 rc = 1;
787         }
788 
789         return rc;
790 }
791 
792 /*
793  * struct dlm_query_join_packet is made up of four one-byte fields.  They
794  * are effectively in big-endian order already.  However, little-endian
795  * machines swap them before putting the packet on the wire (because
796  * query_join's response is a status, and that status is treated as a u32
797  * on the wire).  Thus, a big-endian and little-endian machines will treat
798  * this structure differently.
799  *
800  * The solution is to have little-endian machines swap the structure when
801  * converting from the structure to the u32 representation.  This will
802  * result in the structure having the correct format on the wire no matter
803  * the host endian format.
804  */
805 static void dlm_query_join_packet_to_wire(struct dlm_query_join_packet *packet,
806                                           u32 *wire)
807 {
808         union dlm_query_join_response response;
809 
810         response.packet = *packet;
811         *wire = be32_to_cpu(response.intval);
812 }
813 
814 static void dlm_query_join_wire_to_packet(u32 wire,
815                                           struct dlm_query_join_packet *packet)
816 {
817         union dlm_query_join_response response;
818 
819         response.intval = cpu_to_be32(wire);
820         *packet = response.packet;
821 }
822 
823 static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
824                                   void **ret_data)
825 {
826         struct dlm_query_join_request *query;
827         struct dlm_query_join_packet packet = {
828                 .code = JOIN_DISALLOW,
829         };
830         struct dlm_ctxt *dlm = NULL;
831         u32 response;
832         u8 nodenum;
833 
834         query = (struct dlm_query_join_request *) msg->buf;
835 
836         mlog(0, "node %u wants to join domain %s\n", query->node_idx,
837                   query->domain);
838 
839         /*
840          * If heartbeat doesn't consider the node live, tell it
841          * to back off and try again.  This gives heartbeat a chance
842          * to catch up.
843          */
844         if (!o2hb_check_node_heartbeating(query->node_idx)) {
845                 mlog(0, "node %u is not in our live map yet\n",
846                      query->node_idx);
847 
848                 packet.code = JOIN_DISALLOW;
849                 goto respond;
850         }
851 
852         packet.code = JOIN_OK_NO_MAP;
853 
854         spin_lock(&dlm_domain_lock);
855         dlm = __dlm_lookup_domain_full(query->domain, query->name_len);
856         if (!dlm)
857                 goto unlock_respond;
858 
859         /*
860          * There is a small window where the joining node may not see the
861          * node(s) that just left but still part of the cluster. DISALLOW
862          * join request if joining node has different node map.
863          */
864         nodenum=0;
865         while (nodenum < O2NM_MAX_NODES) {
866                 if (test_bit(nodenum, dlm->domain_map)) {
867                         if (!byte_test_bit(nodenum, query->node_map)) {
868                                 mlog(0, "disallow join as node %u does not "
869                                      "have node %u in its nodemap\n",
870                                      query->node_idx, nodenum);
871                                 packet.code = JOIN_DISALLOW;
872                                 goto unlock_respond;
873                         }
874                 }
875                 nodenum++;
876         }
877 
878         /* Once the dlm ctxt is marked as leaving then we don't want
879          * to be put in someone's domain map.
880          * Also, explicitly disallow joining at certain troublesome
881          * times (ie. during recovery). */
882         if (dlm && dlm->dlm_state != DLM_CTXT_LEAVING) {
883                 int bit = query->node_idx;
884                 spin_lock(&dlm->spinlock);
885 
886                 if (dlm->dlm_state == DLM_CTXT_NEW &&
887                     dlm->joining_node == DLM_LOCK_RES_OWNER_UNKNOWN) {
888                         /*If this is a brand new context and we
889                          * haven't started our join process yet, then
890                          * the other node won the race. */
891                         packet.code = JOIN_OK_NO_MAP;
892                 } else if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
893                         /* Disallow parallel joins. */
894                         packet.code = JOIN_DISALLOW;
895                 } else if (dlm->reco.state & DLM_RECO_STATE_ACTIVE) {
896                         mlog(0, "node %u trying to join, but recovery "
897                              "is ongoing.\n", bit);
898                         packet.code = JOIN_DISALLOW;
899                 } else if (test_bit(bit, dlm->recovery_map)) {
900                         mlog(0, "node %u trying to join, but it "
901                              "still needs recovery.\n", bit);
902                         packet.code = JOIN_DISALLOW;
903                 } else if (test_bit(bit, dlm->domain_map)) {
904                         mlog(0, "node %u trying to join, but it "
905                              "is still in the domain! needs recovery?\n",
906                              bit);
907                         packet.code = JOIN_DISALLOW;
908                 } else {
909                         /* Alright we're fully a part of this domain
910                          * so we keep some state as to who's joining
911                          * and indicate to him that needs to be fixed
912                          * up. */
913 
914                         /* Make sure we speak compatible locking protocols.  */
915                         if (dlm_query_join_proto_check("DLM", bit,
916                                                        &dlm->dlm_locking_proto,
917                                                        &query->dlm_proto)) {
918                                 packet.code = JOIN_PROTOCOL_MISMATCH;
919                         } else if (dlm_query_join_proto_check("fs", bit,
920                                                               &dlm->fs_locking_proto,
921                                                               &query->fs_proto)) {
922                                 packet.code = JOIN_PROTOCOL_MISMATCH;
923                         } else {
924                                 packet.dlm_minor = query->dlm_proto.pv_minor;
925                                 packet.fs_minor = query->fs_proto.pv_minor;
926                                 packet.code = JOIN_OK;
927                                 __dlm_set_joining_node(dlm, query->node_idx);
928                         }
929                 }
930 
931                 spin_unlock(&dlm->spinlock);
932         }
933 unlock_respond:
934         spin_unlock(&dlm_domain_lock);
935 
936 respond:
937         mlog(0, "We respond with %u\n", packet.code);
938 
939         dlm_query_join_packet_to_wire(&packet, &response);
940         return response;
941 }
942 
943 static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data,
944                                      void **ret_data)
945 {
946         struct dlm_assert_joined *assert;
947         struct dlm_ctxt *dlm = NULL;
948 
949         assert = (struct dlm_assert_joined *) msg->buf;
950 
951         mlog(0, "node %u asserts join on domain %s\n", assert->node_idx,
952                   assert->domain);
953 
954         spin_lock(&dlm_domain_lock);
955         dlm = __dlm_lookup_domain_full(assert->domain, assert->name_len);
956         /* XXX should we consider no dlm ctxt an error? */
957         if (dlm) {
958                 spin_lock(&dlm->spinlock);
959 
960                 /* Alright, this node has officially joined our
961                  * domain. Set him in the map and clean up our
962                  * leftover join state. */
963                 BUG_ON(dlm->joining_node != assert->node_idx);
964                 set_bit(assert->node_idx, dlm->domain_map);
965                 clear_bit(assert->node_idx, dlm->exit_domain_map);
966                 __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
967 
968                 printk(KERN_NOTICE "o2dlm: Node %u joins domain %s ",
969                        assert->node_idx, dlm->name);
970                 __dlm_print_nodes(dlm);
971 
972                 /* notify anything attached to the heartbeat events */
973                 dlm_hb_event_notify_attached(dlm, assert->node_idx, 1);
974 
975                 spin_unlock(&dlm->spinlock);
976         }
977         spin_unlock(&dlm_domain_lock);
978 
979         return 0;
980 }
981 
982 static int dlm_match_regions(struct dlm_ctxt *dlm,
983                              struct dlm_query_region *qr,
984                              char *local, int locallen)
985 {
986         char *remote = qr->qr_regions;
987         char *l, *r;
988         int localnr, i, j, foundit;
989         int status = 0;
990 
991         if (!o2hb_global_heartbeat_active()) {
992                 if (qr->qr_numregions) {
993                         mlog(ML_ERROR, "Domain %s: Joining node %d has global "
994                              "heartbeat enabled but local node %d does not\n",
995                              qr->qr_domain, qr->qr_node, dlm->node_num);
996                         status = -EINVAL;
997                 }
998                 goto bail;
999         }
1000 
1001         if (o2hb_global_heartbeat_active() && !qr->qr_numregions) {
1002                 mlog(ML_ERROR, "Domain %s: Local node %d has global "
1003                      "heartbeat enabled but joining node %d does not\n",
1004                      qr->qr_domain, dlm->node_num, qr->qr_node);
1005                 status = -EINVAL;
1006                 goto bail;
1007         }
1008 
1009         r = remote;
1010         for (i = 0; i < qr->qr_numregions; ++i) {
1011                 mlog(0, "Region %.*s\n", O2HB_MAX_REGION_NAME_LEN, r);
1012                 r += O2HB_MAX_REGION_NAME_LEN;
1013         }
1014 
1015         localnr = min(O2NM_MAX_REGIONS, locallen/O2HB_MAX_REGION_NAME_LEN);
1016         localnr = o2hb_get_all_regions(local, (u8)localnr);
1017 
1018         /* compare local regions with remote */
1019         l = local;
1020         for (i = 0; i < localnr; ++i) {
1021                 foundit = 0;
1022                 r = remote;
1023                 for (j = 0; j <= qr->qr_numregions; ++j) {
1024                         if (!memcmp(l, r, O2HB_MAX_REGION_NAME_LEN)) {
1025                                 foundit = 1;
1026                                 break;
1027                         }
1028                         r += O2HB_MAX_REGION_NAME_LEN;
1029                 }
1030                 if (!foundit) {
1031                         status = -EINVAL;
1032                         mlog(ML_ERROR, "Domain %s: Region '%.*s' registered "
1033                              "in local node %d but not in joining node %d\n",
1034                              qr->qr_domain, O2HB_MAX_REGION_NAME_LEN, l,
1035                              dlm->node_num, qr->qr_node);
1036                         goto bail;
1037                 }
1038                 l += O2HB_MAX_REGION_NAME_LEN;
1039         }
1040 
1041         /* compare remote with local regions */
1042         r = remote;
1043         for (i = 0; i < qr->qr_numregions; ++i) {
1044                 foundit = 0;
1045                 l = local;
1046                 for (j = 0; j < localnr; ++j) {
1047                         if (!memcmp(r, l, O2HB_MAX_REGION_NAME_LEN)) {
1048                                 foundit = 1;
1049                                 break;
1050                         }
1051                         l += O2HB_MAX_REGION_NAME_LEN;
1052                 }
1053                 if (!foundit) {
1054                         status = -EINVAL;
1055                         mlog(ML_ERROR, "Domain %s: Region '%.*s' registered "
1056                              "in joining node %d but not in local node %d\n",
1057                              qr->qr_domain, O2HB_MAX_REGION_NAME_LEN, r,
1058                              qr->qr_node, dlm->node_num);
1059                         goto bail;
1060                 }
1061                 r += O2HB_MAX_REGION_NAME_LEN;
1062         }
1063 
1064 bail:
1065         return status;
1066 }
1067 
1068 static int dlm_send_regions(struct dlm_ctxt *dlm, unsigned long *node_map)
1069 {
1070         struct dlm_query_region *qr = NULL;
1071         int status, ret = 0, i;
1072         char *p;
1073 
1074         if (find_next_bit(node_map, O2NM_MAX_NODES, 0) >= O2NM_MAX_NODES)
1075                 goto bail;
1076 
1077         qr = kzalloc(sizeof(struct dlm_query_region), GFP_KERNEL);
1078         if (!qr) {
1079                 ret = -ENOMEM;
1080                 mlog_errno(ret);
1081                 goto bail;
1082         }
1083 
1084         qr->qr_node = dlm->node_num;
1085         qr->qr_namelen = strlen(dlm->name);
1086         memcpy(qr->qr_domain, dlm->name, qr->qr_namelen);
1087         /* if local hb, the numregions will be zero */
1088         if (o2hb_global_heartbeat_active())
1089                 qr->qr_numregions = o2hb_get_all_regions(qr->qr_regions,
1090                                                          O2NM_MAX_REGIONS);
1091 
1092         p = qr->qr_regions;
1093         for (i = 0; i < qr->qr_numregions; ++i, p += O2HB_MAX_REGION_NAME_LEN)
1094                 mlog(0, "Region %.*s\n", O2HB_MAX_REGION_NAME_LEN, p);
1095 
1096         i = -1;
1097         while ((i = find_next_bit(node_map, O2NM_MAX_NODES,
1098                                   i + 1)) < O2NM_MAX_NODES) {
1099                 if (i == dlm->node_num)
1100                         continue;
1101 
1102                 mlog(0, "Sending regions to node %d\n", i);
1103 
1104                 ret = o2net_send_message(DLM_QUERY_REGION, DLM_MOD_KEY, qr,
1105                                          sizeof(struct dlm_query_region),
1106                                          i, &status);
1107                 if (ret >= 0)
1108                         ret = status;
1109                 if (ret) {
1110                         mlog(ML_ERROR, "Region mismatch %d, node %d\n",
1111                              ret, i);
1112                         break;
1113                 }
1114         }
1115 
1116 bail:
1117         kfree(qr);
1118         return ret;
1119 }
1120 
1121 static int dlm_query_region_handler(struct o2net_msg *msg, u32 len,
1122                                     void *data, void **ret_data)
1123 {
1124         struct dlm_query_region *qr;
1125         struct dlm_ctxt *dlm = NULL;
1126         char *local = NULL;
1127         int status = 0;
1128         int locked = 0;
1129 
1130         qr = (struct dlm_query_region *) msg->buf;
1131 
1132         mlog(0, "Node %u queries hb regions on domain %s\n", qr->qr_node,
1133              qr->qr_domain);
1134 
1135         /* buffer used in dlm_mast_regions() */
1136         local = kmalloc(sizeof(qr->qr_regions), GFP_KERNEL);
1137         if (!local) {
1138                 status = -ENOMEM;
1139                 goto bail;
1140         }
1141 
1142         status = -EINVAL;
1143 
1144         spin_lock(&dlm_domain_lock);
1145         dlm = __dlm_lookup_domain_full(qr->qr_domain, qr->qr_namelen);
1146         if (!dlm) {
1147                 mlog(ML_ERROR, "Node %d queried hb regions on domain %s "
1148                      "before join domain\n", qr->qr_node, qr->qr_domain);
1149                 goto bail;
1150         }
1151 
1152         spin_lock(&dlm->spinlock);
1153         locked = 1;
1154         if (dlm->joining_node != qr->qr_node) {
1155                 mlog(ML_ERROR, "Node %d queried hb regions on domain %s "
1156                      "but joining node is %d\n", qr->qr_node, qr->qr_domain,
1157                      dlm->joining_node);
1158                 goto bail;
1159         }
1160 
1161         /* Support for global heartbeat was added in 1.1 */
1162         if (dlm->dlm_locking_proto.pv_major == 1 &&
1163             dlm->dlm_locking_proto.pv_minor == 0) {
1164                 mlog(ML_ERROR, "Node %d queried hb regions on domain %s "
1165                      "but active dlm protocol is %d.%d\n", qr->qr_node,
1166                      qr->qr_domain, dlm->dlm_locking_proto.pv_major,
1167                      dlm->dlm_locking_proto.pv_minor);
1168                 goto bail;
1169         }
1170 
1171         status = dlm_match_regions(dlm, qr, local, sizeof(qr->qr_regions));
1172 
1173 bail:
1174         if (locked)
1175                 spin_unlock(&dlm->spinlock);
1176         spin_unlock(&dlm_domain_lock);
1177 
1178         kfree(local);
1179 
1180         return status;
1181 }
1182 
1183 static int dlm_match_nodes(struct dlm_ctxt *dlm, struct dlm_query_nodeinfo *qn)
1184 {
1185         struct o2nm_node *local;
1186         struct dlm_node_info *remote;
1187         int i, j;
1188         int status = 0;
1189 
1190         for (j = 0; j < qn->qn_numnodes; ++j)
1191                 mlog(0, "Node %3d, %pI4:%u\n", qn->qn_nodes[j].ni_nodenum,
1192                      &(qn->qn_nodes[j].ni_ipv4_address),
1193                      ntohs(qn->qn_nodes[j].ni_ipv4_port));
1194 
1195         for (i = 0; i < O2NM_MAX_NODES && !status; ++i) {
1196                 local = o2nm_get_node_by_num(i);
1197                 remote = NULL;
1198                 for (j = 0; j < qn->qn_numnodes; ++j) {
1199                         if (qn->qn_nodes[j].ni_nodenum == i) {
1200                                 remote = &(qn->qn_nodes[j]);
1201                                 break;
1202                         }
1203                 }
1204 
1205                 if (!local && !remote)
1206                         continue;
1207 
1208                 if ((local && !remote) || (!local && remote))
1209                         status = -EINVAL;
1210 
1211                 if (!status &&
1212                     ((remote->ni_nodenum != local->nd_num) ||
1213                      (remote->ni_ipv4_port != local->nd_ipv4_port) ||
1214                      (remote->ni_ipv4_address != local->nd_ipv4_address)))
1215                         status = -EINVAL;
1216 
1217                 if (status) {
1218                         if (remote && !local)
1219                                 mlog(ML_ERROR, "Domain %s: Node %d (%pI4:%u) "
1220                                      "registered in joining node %d but not in "
1221                                      "local node %d\n", qn->qn_domain,
1222                                      remote->ni_nodenum,
1223                                      &(remote->ni_ipv4_address),
1224                                      ntohs(remote->ni_ipv4_port),
1225                                      qn->qn_nodenum, dlm->node_num);
1226                         if (local && !remote)
1227                                 mlog(ML_ERROR, "Domain %s: Node %d (%pI4:%u) "
1228                                      "registered in local node %d but not in "
1229                                      "joining node %d\n", qn->qn_domain,
1230                                      local->nd_num, &(local->nd_ipv4_address),
1231                                      ntohs(local->nd_ipv4_port),
1232                                      dlm->node_num, qn->qn_nodenum);
1233                         BUG_ON((!local && !remote));
1234                 }
1235 
1236                 if (local)
1237                         o2nm_node_put(local);
1238         }
1239 
1240         return status;
1241 }
1242 
1243 static int dlm_send_nodeinfo(struct dlm_ctxt *dlm, unsigned long *node_map)
1244 {
1245         struct dlm_query_nodeinfo *qn = NULL;
1246         struct o2nm_node *node;
1247         int ret = 0, status, count, i;
1248 
1249         if (find_next_bit(node_map, O2NM_MAX_NODES, 0) >= O2NM_MAX_NODES)
1250                 goto bail;
1251 
1252         qn = kzalloc(sizeof(struct dlm_query_nodeinfo), GFP_KERNEL);
1253         if (!qn) {
1254                 ret = -ENOMEM;
1255                 mlog_errno(ret);
1256                 goto bail;
1257         }
1258 
1259         for (i = 0, count = 0; i < O2NM_MAX_NODES; ++i) {
1260                 node = o2nm_get_node_by_num(i);
1261                 if (!node)
1262                         continue;
1263                 qn->qn_nodes[count].ni_nodenum = node->nd_num;
1264                 qn->qn_nodes[count].ni_ipv4_port = node->nd_ipv4_port;
1265                 qn->qn_nodes[count].ni_ipv4_address = node->nd_ipv4_address;
1266                 mlog(0, "Node %3d, %pI4:%u\n", node->nd_num,
1267                      &(node->nd_ipv4_address), ntohs(node->nd_ipv4_port));
1268                 ++count;
1269                 o2nm_node_put(node);
1270         }
1271 
1272         qn->qn_nodenum = dlm->node_num;
1273         qn->qn_numnodes = count;
1274         qn->qn_namelen = strlen(dlm->name);
1275         memcpy(qn->qn_domain, dlm->name, qn->qn_namelen);
1276 
1277         i = -1;
1278         while ((i = find_next_bit(node_map, O2NM_MAX_NODES,
1279                                   i + 1)) < O2NM_MAX_NODES) {
1280                 if (i == dlm->node_num)
1281                         continue;
1282 
1283                 mlog(0, "Sending nodeinfo to node %d\n", i);
1284 
1285                 ret = o2net_send_message(DLM_QUERY_NODEINFO, DLM_MOD_KEY,
1286                                          qn, sizeof(struct dlm_query_nodeinfo),
1287                                          i, &status);
1288                 if (ret >= 0)
1289                         ret = status;
1290                 if (ret) {
1291                         mlog(ML_ERROR, "node mismatch %d, node %d\n", ret, i);
1292                         break;
1293                 }
1294         }
1295 
1296 bail:
1297         kfree(qn);
1298         return ret;
1299 }
1300 
1301 static int dlm_query_nodeinfo_handler(struct o2net_msg *msg, u32 len,
1302                                       void *data, void **ret_data)
1303 {
1304         struct dlm_query_nodeinfo *qn;
1305         struct dlm_ctxt *dlm = NULL;
1306         int locked = 0, status = -EINVAL;
1307 
1308         qn = (struct dlm_query_nodeinfo *) msg->buf;
1309 
1310         mlog(0, "Node %u queries nodes on domain %s\n", qn->qn_nodenum,
1311              qn->qn_domain);
1312 
1313         spin_lock(&dlm_domain_lock);
1314         dlm = __dlm_lookup_domain_full(qn->qn_domain, qn->qn_namelen);
1315         if (!dlm) {
1316                 mlog(ML_ERROR, "Node %d queried nodes on domain %s before "
1317                      "join domain\n", qn->qn_nodenum, qn->qn_domain);
1318                 goto bail;
1319         }
1320 
1321         spin_lock(&dlm->spinlock);
1322         locked = 1;
1323         if (dlm->joining_node != qn->qn_nodenum) {
1324                 mlog(ML_ERROR, "Node %d queried nodes on domain %s but "
1325                      "joining node is %d\n", qn->qn_nodenum, qn->qn_domain,
1326                      dlm->joining_node);
1327                 goto bail;
1328         }
1329 
1330         /* Support for node query was added in 1.1 */
1331         if (dlm->dlm_locking_proto.pv_major == 1 &&
1332             dlm->dlm_locking_proto.pv_minor == 0) {
1333                 mlog(ML_ERROR, "Node %d queried nodes on domain %s "
1334                      "but active dlm protocol is %d.%d\n", qn->qn_nodenum,
1335                      qn->qn_domain, dlm->dlm_locking_proto.pv_major,
1336                      dlm->dlm_locking_proto.pv_minor);
1337                 goto bail;
1338         }
1339 
1340         status = dlm_match_nodes(dlm, qn);
1341 
1342 bail:
1343         if (locked)
1344                 spin_unlock(&dlm->spinlock);
1345         spin_unlock(&dlm_domain_lock);
1346 
1347         return status;
1348 }
1349 
1350 static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data,
1351                                    void **ret_data)
1352 {
1353         struct dlm_cancel_join *cancel;
1354         struct dlm_ctxt *dlm = NULL;
1355 
1356         cancel = (struct dlm_cancel_join *) msg->buf;
1357 
1358         mlog(0, "node %u cancels join on domain %s\n", cancel->node_idx,
1359                   cancel->domain);
1360 
1361         spin_lock(&dlm_domain_lock);
1362         dlm = __dlm_lookup_domain_full(cancel->domain, cancel->name_len);
1363 
1364         if (dlm) {
1365                 spin_lock(&dlm->spinlock);
1366 
1367                 /* Yikes, this guy wants to cancel his join. No
1368                  * problem, we simply cleanup our join state. */
1369                 BUG_ON(dlm->joining_node != cancel->node_idx);
1370                 __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
1371 
1372                 spin_unlock(&dlm->spinlock);
1373         }
1374         spin_unlock(&dlm_domain_lock);
1375 
1376         return 0;
1377 }
1378 
1379 static int dlm_send_one_join_cancel(struct dlm_ctxt *dlm,
1380                                     unsigned int node)
1381 {
1382         int status;
1383         struct dlm_cancel_join cancel_msg;
1384 
1385         memset(&cancel_msg, 0, sizeof(cancel_msg));
1386         cancel_msg.node_idx = dlm->node_num;
1387         cancel_msg.name_len = strlen(dlm->name);
1388         memcpy(cancel_msg.domain, dlm->name, cancel_msg.name_len);
1389 
1390         status = o2net_send_message(DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
1391                                     &cancel_msg, sizeof(cancel_msg), node,
1392                                     NULL);
1393         if (status < 0) {
1394                 mlog(ML_ERROR, "Error %d when sending message %u (key 0x%x) to "
1395                      "node %u\n", status, DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
1396                      node);
1397                 goto bail;
1398         }
1399 
1400 bail:
1401         return status;
1402 }
1403 
1404 /* map_size should be in bytes. */
1405 static int dlm_send_join_cancels(struct dlm_ctxt *dlm,
1406                                  unsigned long *node_map,
1407                                  unsigned int map_size)
1408 {
1409         int status, tmpstat;
1410         unsigned int node;
1411 
1412         if (map_size != (BITS_TO_LONGS(O2NM_MAX_NODES) *
1413                          sizeof(unsigned long))) {
1414                 mlog(ML_ERROR,
1415                      "map_size %u != BITS_TO_LONGS(O2NM_MAX_NODES) %u\n",
1416                      map_size, (unsigned)BITS_TO_LONGS(O2NM_MAX_NODES));
1417                 return -EINVAL;
1418         }
1419 
1420         status = 0;
1421         node = -1;
1422         while ((node = find_next_bit(node_map, O2NM_MAX_NODES,
1423                                      node + 1)) < O2NM_MAX_NODES) {
1424                 if (node == dlm->node_num)
1425                         continue;
1426 
1427                 tmpstat = dlm_send_one_join_cancel(dlm, node);
1428                 if (tmpstat) {
1429                         mlog(ML_ERROR, "Error return %d cancelling join on "
1430                              "node %d\n", tmpstat, node);
1431                         if (!status)
1432                                 status = tmpstat;
1433                 }
1434         }
1435 
1436         if (status)
1437                 mlog_errno(status);
1438         return status;
1439 }
1440 
1441 static int dlm_request_join(struct dlm_ctxt *dlm,
1442                             int node,
1443                             enum dlm_query_join_response_code *response)
1444 {
1445         int status;
1446         struct dlm_query_join_request join_msg;
1447         struct dlm_query_join_packet packet;
1448         u32 join_resp;
1449 
1450         mlog(0, "querying node %d\n", node);
1451 
1452         memset(&join_msg, 0, sizeof(join_msg));
1453         join_msg.node_idx = dlm->node_num;
1454         join_msg.name_len = strlen(dlm->name);
1455         memcpy(join_msg.domain, dlm->name, join_msg.name_len);
1456         join_msg.dlm_proto = dlm->dlm_locking_proto;
1457         join_msg.fs_proto = dlm->fs_locking_proto;
1458 
1459         /* copy live node map to join message */
1460         byte_copymap(join_msg.node_map, dlm->live_nodes_map, O2NM_MAX_NODES);
1461 
1462         status = o2net_send_message(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY, &join_msg,
1463                                     sizeof(join_msg), node, &join_resp);
1464         if (status < 0 && status != -ENOPROTOOPT) {
1465                 mlog(ML_ERROR, "Error %d when sending message %u (key 0x%x) to "
1466                      "node %u\n", status, DLM_QUERY_JOIN_MSG, DLM_MOD_KEY,
1467                      node);
1468                 goto bail;
1469         }
1470         dlm_query_join_wire_to_packet(join_resp, &packet);
1471 
1472         /* -ENOPROTOOPT from the net code means the other side isn't
1473             listening for our message type -- that's fine, it means
1474             his dlm isn't up, so we can consider him a 'yes' but not
1475             joined into the domain.  */
1476         if (status == -ENOPROTOOPT) {
1477                 status = 0;
1478                 *response = JOIN_OK_NO_MAP;
1479         } else if (packet.code == JOIN_DISALLOW ||
1480                    packet.code == JOIN_OK_NO_MAP) {
1481                 *response = packet.code;
1482         } else if (packet.code == JOIN_PROTOCOL_MISMATCH) {
1483                 mlog(ML_NOTICE,
1484                      "This node requested DLM locking protocol %u.%u and "
1485                      "filesystem locking protocol %u.%u.  At least one of "
1486                      "the protocol versions on node %d is not compatible, "
1487                      "disconnecting\n",
1488                      dlm->dlm_locking_proto.pv_major,
1489                      dlm->dlm_locking_proto.pv_minor,
1490                      dlm->fs_locking_proto.pv_major,
1491                      dlm->fs_locking_proto.pv_minor,
1492                      node);
1493                 status = -EPROTO;
1494                 *response = packet.code;
1495         } else if (packet.code == JOIN_OK) {
1496                 *response = packet.code;
1497                 /* Use the same locking protocol as the remote node */
1498                 dlm->dlm_locking_proto.pv_minor = packet.dlm_minor;
1499                 dlm->fs_locking_proto.pv_minor = packet.fs_minor;
1500                 mlog(0,
1501                      "Node %d responds JOIN_OK with DLM locking protocol "
1502                      "%u.%u and fs locking protocol %u.%u\n",
1503                      node,
1504                      dlm->dlm_locking_proto.pv_major,
1505                      dlm->dlm_locking_proto.pv_minor,
1506                      dlm->fs_locking_proto.pv_major,
1507                      dlm->fs_locking_proto.pv_minor);
1508         } else {
1509                 status = -EINVAL;
1510                 mlog(ML_ERROR, "invalid response %d from node %u\n",
1511                      packet.code, node);
1512         }
1513 
1514         mlog(0, "status %d, node %d response is %d\n", status, node,
1515              *response);
1516 
1517 bail:
1518         return status;
1519 }
1520 
1521 static int dlm_send_one_join_assert(struct dlm_ctxt *dlm,
1522                                     unsigned int node)
1523 {
1524         int status;
1525         struct dlm_assert_joined assert_msg;
1526 
1527         mlog(0, "Sending join assert to node %u\n", node);
1528 
1529         memset(&assert_msg, 0, sizeof(assert_msg));
1530         assert_msg.node_idx = dlm->node_num;
1531         assert_msg.name_len = strlen(dlm->name);
1532         memcpy(assert_msg.domain, dlm->name, assert_msg.name_len);
1533 
1534         status = o2net_send_message(DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
1535                                     &assert_msg, sizeof(assert_msg), node,
1536                                     NULL);
1537         if (status < 0)
1538                 mlog(ML_ERROR, "Error %d when sending message %u (key 0x%x) to "
1539                      "node %u\n", status, DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
1540                      node);
1541 
1542         return status;
1543 }
1544 
1545 static void dlm_send_join_asserts(struct dlm_ctxt *dlm,
1546                                   unsigned long *node_map)
1547 {
1548         int status, node, live;
1549 
1550         status = 0;
1551         node = -1;
1552         while ((node = find_next_bit(node_map, O2NM_MAX_NODES,
1553                                      node + 1)) < O2NM_MAX_NODES) {
1554                 if (node == dlm->node_num)
1555                         continue;
1556 
1557                 do {
1558                         /* It is very important that this message be
1559                          * received so we spin until either the node
1560                          * has died or it gets the message. */
1561                         status = dlm_send_one_join_assert(dlm, node);
1562 
1563                         spin_lock(&dlm->spinlock);
1564                         live = test_bit(node, dlm->live_nodes_map);
1565                         spin_unlock(&dlm->spinlock);
1566 
1567                         if (status) {
1568                                 mlog(ML_ERROR, "Error return %d asserting "
1569                                      "join on node %d\n", status, node);
1570 
1571                                 /* give us some time between errors... */
1572                                 if (live)
1573                                         msleep(DLM_DOMAIN_BACKOFF_MS);
1574                         }
1575                 } while (status && live);
1576         }
1577 }
1578 
1579 struct domain_join_ctxt {
1580         unsigned long live_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1581         unsigned long yes_resp_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1582 };
1583 
1584 static int dlm_should_restart_join(struct dlm_ctxt *dlm,
1585                                    struct domain_join_ctxt *ctxt,
1586                                    enum dlm_query_join_response_code response)
1587 {
1588         int ret;
1589 
1590         if (response == JOIN_DISALLOW) {
1591                 mlog(0, "Latest response of disallow -- should restart\n");
1592                 return 1;
1593         }
1594 
1595         spin_lock(&dlm->spinlock);
1596         /* For now, we restart the process if the node maps have
1597          * changed at all */
1598         ret = memcmp(ctxt->live_map, dlm->live_nodes_map,
1599                      sizeof(dlm->live_nodes_map));
1600         spin_unlock(&dlm->spinlock);
1601 
1602         if (ret)
1603                 mlog(0, "Node maps changed -- should restart\n");
1604 
1605         return ret;
1606 }
1607 
1608 static int dlm_try_to_join_domain(struct dlm_ctxt *dlm)
1609 {
1610         int status = 0, tmpstat, node;
1611         struct domain_join_ctxt *ctxt;
1612         enum dlm_query_join_response_code response = JOIN_DISALLOW;
1613 
1614         mlog(0, "%p", dlm);
1615 
1616         ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL);
1617         if (!ctxt) {
1618                 status = -ENOMEM;
1619                 mlog_errno(status);
1620                 goto bail;
1621         }
1622 
1623         /* group sem locking should work for us here -- we're already
1624          * registered for heartbeat events so filling this should be
1625          * atomic wrt getting those handlers called. */
1626         o2hb_fill_node_map(dlm->live_nodes_map, sizeof(dlm->live_nodes_map));
1627 
1628         spin_lock(&dlm->spinlock);
1629         memcpy(ctxt->live_map, dlm->live_nodes_map, sizeof(ctxt->live_map));
1630 
1631         __dlm_set_joining_node(dlm, dlm->node_num);
1632 
1633         spin_unlock(&dlm->spinlock);
1634 
1635         node = -1;
1636         while ((node = find_next_bit(ctxt->live_map, O2NM_MAX_NODES,
1637                                      node + 1)) < O2NM_MAX_NODES) {
1638                 if (node == dlm->node_num)
1639                         continue;
1640 
1641                 status = dlm_request_join(dlm, node, &response);
1642                 if (status < 0) {
1643                         mlog_errno(status);
1644                         goto bail;
1645                 }
1646 
1647                 /* Ok, either we got a response or the node doesn't have a
1648                  * dlm up. */
1649                 if (response == JOIN_OK)
1650                         set_bit(node, ctxt->yes_resp_map);
1651 
1652                 if (dlm_should_restart_join(dlm, ctxt, response)) {
1653                         status = -EAGAIN;
1654                         goto bail;
1655                 }
1656         }
1657 
1658         mlog(0, "Yay, done querying nodes!\n");
1659 
1660         /* Yay, everyone agree's we can join the domain. My domain is
1661          * comprised of all nodes who were put in the
1662          * yes_resp_map. Copy that into our domain map and send a join
1663          * assert message to clean up everyone elses state. */
1664         spin_lock(&dlm->spinlock);
1665         memcpy(dlm->domain_map, ctxt->yes_resp_map,
1666                sizeof(ctxt->yes_resp_map));
1667         set_bit(dlm->node_num, dlm->domain_map);
1668         spin_unlock(&dlm->spinlock);
1669 
1670         /* Support for global heartbeat and node info was added in 1.1 */
1671         if (dlm->dlm_locking_proto.pv_major > 1 ||
1672             dlm->dlm_locking_proto.pv_minor > 0) {
1673                 status = dlm_send_nodeinfo(dlm, ctxt->yes_resp_map);
1674                 if (status) {
1675                         mlog_errno(status);
1676                         goto bail;
1677                 }
1678                 status = dlm_send_regions(dlm, ctxt->yes_resp_map);
1679                 if (status) {
1680                         mlog_errno(status);
1681                         goto bail;
1682                 }
1683         }
1684 
1685         dlm_send_join_asserts(dlm, ctxt->yes_resp_map);
1686 
1687         /* Joined state *must* be set before the joining node
1688          * information, otherwise the query_join handler may read no
1689          * current joiner but a state of NEW and tell joining nodes
1690          * we're not in the domain. */
1691         spin_lock(&dlm_domain_lock);
1692         dlm->dlm_state = DLM_CTXT_JOINED;
1693         dlm->num_joins++;
1694         spin_unlock(&dlm_domain_lock);
1695 
1696 bail:
1697         spin_lock(&dlm->spinlock);
1698         __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
1699         if (!status) {
1700                 printk(KERN_NOTICE "o2dlm: Joining domain %s ", dlm->name);
1701                 __dlm_print_nodes(dlm);
1702         }
1703         spin_unlock(&dlm->spinlock);
1704 
1705         if (ctxt) {
1706                 /* Do we need to send a cancel message to any nodes? */
1707                 if (status < 0) {
1708                         tmpstat = dlm_send_join_cancels(dlm,
1709                                                         ctxt->yes_resp_map,
1710                                                         sizeof(ctxt->yes_resp_map));
1711                         if (tmpstat < 0)
1712                                 mlog_errno(tmpstat);
1713                 }
1714                 kfree(ctxt);
1715         }
1716 
1717         mlog(0, "returning %d\n", status);
1718         return status;
1719 }
1720 
1721 static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm)
1722 {
1723         o2hb_unregister_callback(dlm->name, &dlm->dlm_hb_up);
1724         o2hb_unregister_callback(dlm->name, &dlm->dlm_hb_down);
1725         o2net_unregister_handler_list(&dlm->dlm_domain_handlers);
1726 }
1727 
1728 static int dlm_register_domain_handlers(struct dlm_ctxt *dlm)
1729 {
1730         int status;
1731 
1732         mlog(0, "registering handlers.\n");
1733 
1734         o2hb_setup_callback(&dlm->dlm_hb_down, O2HB_NODE_DOWN_CB,
1735                             dlm_hb_node_down_cb, dlm, DLM_HB_NODE_DOWN_PRI);
1736         status = o2hb_register_callback(dlm->name, &dlm->dlm_hb_down);
1737         if (status)
1738                 goto bail;
1739 
1740         o2hb_setup_callback(&dlm->dlm_hb_up, O2HB_NODE_UP_CB,
1741                             dlm_hb_node_up_cb, dlm, DLM_HB_NODE_UP_PRI);
1742         status = o2hb_register_callback(dlm->name, &dlm->dlm_hb_up);
1743         if (status)
1744                 goto bail;
1745 
1746         status = o2net_register_handler(DLM_MASTER_REQUEST_MSG, dlm->key,
1747                                         sizeof(struct dlm_master_request),
1748                                         dlm_master_request_handler,
1749                                         dlm, NULL, &dlm->dlm_domain_handlers);
1750         if (status)
1751                 goto bail;
1752 
1753         status = o2net_register_handler(DLM_ASSERT_MASTER_MSG, dlm->key,
1754                                         sizeof(struct dlm_assert_master),
1755                                         dlm_assert_master_handler,
1756                                         dlm, dlm_assert_master_post_handler,
1757                                         &dlm->dlm_domain_handlers);
1758         if (status)
1759                 goto bail;
1760 
1761         status = o2net_register_handler(DLM_CREATE_LOCK_MSG, dlm->key,
1762                                         sizeof(struct dlm_create_lock),
1763                                         dlm_create_lock_handler,
1764                                         dlm, NULL, &dlm->dlm_domain_handlers);
1765         if (status)
1766                 goto bail;
1767 
1768         status = o2net_register_handler(DLM_CONVERT_LOCK_MSG, dlm->key,
1769                                         DLM_CONVERT_LOCK_MAX_LEN,
1770                                         dlm_convert_lock_handler,
1771                                         dlm, NULL, &dlm->dlm_domain_handlers);
1772         if (status)
1773                 goto bail;
1774 
1775         status = o2net_register_handler(DLM_UNLOCK_LOCK_MSG, dlm->key,
1776                                         DLM_UNLOCK_LOCK_MAX_LEN,
1777                                         dlm_unlock_lock_handler,
1778                                         dlm, NULL, &dlm->dlm_domain_handlers);
1779         if (status)
1780                 goto bail;
1781 
1782         status = o2net_register_handler(DLM_PROXY_AST_MSG, dlm->key,
1783                                         DLM_PROXY_AST_MAX_LEN,
1784                                         dlm_proxy_ast_handler,
1785                                         dlm, NULL, &dlm->dlm_domain_handlers);
1786         if (status)
1787                 goto bail;
1788 
1789         status = o2net_register_handler(DLM_EXIT_DOMAIN_MSG, dlm->key,
1790                                         sizeof(struct dlm_exit_domain),
1791                                         dlm_exit_domain_handler,
1792                                         dlm, NULL, &dlm->dlm_domain_handlers);
1793         if (status)
1794                 goto bail;
1795 
1796         status = o2net_register_handler(DLM_DEREF_LOCKRES_MSG, dlm->key,
1797                                         sizeof(struct dlm_deref_lockres),
1798                                         dlm_deref_lockres_handler,
1799                                         dlm, NULL, &dlm->dlm_domain_handlers);
1800         if (status)
1801                 goto bail;
1802 
1803         status = o2net_register_handler(DLM_MIGRATE_REQUEST_MSG, dlm->key,
1804                                         sizeof(struct dlm_migrate_request),
1805                                         dlm_migrate_request_handler,
1806                                         dlm, NULL, &dlm->dlm_domain_handlers);
1807         if (status)
1808                 goto bail;
1809 
1810         status = o2net_register_handler(DLM_MIG_LOCKRES_MSG, dlm->key,
1811                                         DLM_MIG_LOCKRES_MAX_LEN,
1812                                         dlm_mig_lockres_handler,
1813                                         dlm, NULL, &dlm->dlm_domain_handlers);
1814         if (status)
1815                 goto bail;
1816 
1817         status = o2net_register_handler(DLM_MASTER_REQUERY_MSG, dlm->key,
1818                                         sizeof(struct dlm_master_requery),
1819                                         dlm_master_requery_handler,
1820                                         dlm, NULL, &dlm->dlm_domain_handlers);
1821         if (status)
1822                 goto bail;
1823 
1824         status = o2net_register_handler(DLM_LOCK_REQUEST_MSG, dlm->key,
1825                                         sizeof(struct dlm_lock_request),
1826                                         dlm_request_all_locks_handler,
1827                                         dlm, NULL, &dlm->dlm_domain_handlers);
1828         if (status)
1829                 goto bail;
1830 
1831         status = o2net_register_handler(DLM_RECO_DATA_DONE_MSG, dlm->key,
1832                                         sizeof(struct dlm_reco_data_done),
1833                                         dlm_reco_data_done_handler,
1834                                         dlm, NULL, &dlm->dlm_domain_handlers);
1835         if (status)
1836                 goto bail;
1837 
1838         status = o2net_register_handler(DLM_BEGIN_RECO_MSG, dlm->key,
1839                                         sizeof(struct dlm_begin_reco),
1840                                         dlm_begin_reco_handler,
1841                                         dlm, NULL, &dlm->dlm_domain_handlers);
1842         if (status)
1843                 goto bail;
1844 
1845         status = o2net_register_handler(DLM_FINALIZE_RECO_MSG, dlm->key,
1846                                         sizeof(struct dlm_finalize_reco),
1847                                         dlm_finalize_reco_handler,
1848                                         dlm, NULL, &dlm->dlm_domain_handlers);
1849         if (status)
1850                 goto bail;
1851 
1852         status = o2net_register_handler(DLM_BEGIN_EXIT_DOMAIN_MSG, dlm->key,
1853                                         sizeof(struct dlm_exit_domain),
1854                                         dlm_begin_exit_domain_handler,
1855                                         dlm, NULL, &dlm->dlm_domain_handlers);
1856         if (status)
1857                 goto bail;
1858 
1859 bail:
1860         if (status)
1861                 dlm_unregister_domain_handlers(dlm);
1862 
1863         return status;
1864 }
1865 
1866 static int dlm_join_domain(struct dlm_ctxt *dlm)
1867 {
1868         int status;
1869         unsigned int backoff;
1870         unsigned int total_backoff = 0;
1871 
1872         BUG_ON(!dlm);
1873 
1874         mlog(0, "Join domain %s\n", dlm->name);
1875 
1876         status = dlm_register_domain_handlers(dlm);
1877         if (status) {
1878                 mlog_errno(status);
1879                 goto bail;
1880         }
1881 
1882         status = dlm_debug_init(dlm);
1883         if (status < 0) {
1884                 mlog_errno(status);
1885                 goto bail;
1886         }
1887 
1888         status = dlm_launch_thread(dlm);
1889         if (status < 0) {
1890                 mlog_errno(status);
1891                 goto bail;
1892         }
1893 
1894         status = dlm_launch_recovery_thread(dlm);
1895         if (status < 0) {
1896                 mlog_errno(status);
1897                 goto bail;
1898         }
1899 
1900         dlm->dlm_worker = create_singlethread_workqueue("dlm_wq");
1901         if (!dlm->dlm_worker) {
1902                 status = -ENOMEM;
1903                 mlog_errno(status);
1904                 goto bail;
1905         }
1906 
1907         do {
1908                 status = dlm_try_to_join_domain(dlm);
1909 
1910                 /* If we're racing another node to the join, then we
1911                  * need to back off temporarily and let them
1912                  * complete. */
1913 #define DLM_JOIN_TIMEOUT_MSECS  90000
1914                 if (status == -EAGAIN) {
1915                         if (signal_pending(current)) {
1916                                 status = -ERESTARTSYS;
1917                                 goto bail;
1918                         }
1919 
1920                         if (total_backoff >
1921                             msecs_to_jiffies(DLM_JOIN_TIMEOUT_MSECS)) {
1922                                 status = -ERESTARTSYS;
1923                                 mlog(ML_NOTICE, "Timed out joining dlm domain "
1924                                      "%s after %u msecs\n", dlm->name,
1925                                      jiffies_to_msecs(total_backoff));
1926                                 goto bail;
1927                         }
1928 
1929                         /*
1930                          * <chip> After you!
1931                          * <dale> No, after you!
1932                          * <chip> I insist!
1933                          * <dale> But you first!
1934                          * ...
1935                          */
1936                         backoff = (unsigned int)(jiffies & 0x3);
1937                         backoff *= DLM_DOMAIN_BACKOFF_MS;
1938                         total_backoff += backoff;
1939                         mlog(0, "backoff %d\n", backoff);
1940                         msleep(backoff);
1941                 }
1942         } while (status == -EAGAIN);
1943 
1944         if (status < 0) {
1945                 mlog_errno(status);
1946                 goto bail;
1947         }
1948 
1949         status = 0;
1950 bail:
1951         wake_up(&dlm_domain_events);
1952 
1953         if (status) {
1954                 dlm_unregister_domain_handlers(dlm);
1955                 dlm_debug_shutdown(dlm);
1956                 dlm_complete_thread(dlm);
1957                 dlm_complete_recovery_thread(dlm);
1958                 dlm_destroy_dlm_worker(dlm);
1959         }
1960 
1961         return status;
1962 }
1963 
1964 static struct dlm_ctxt *dlm_alloc_ctxt(const char *domain,
1965                                 u32 key)
1966 {
1967         int i;
1968         int ret;
1969         struct dlm_ctxt *dlm = NULL;
1970 
1971         dlm = kzalloc(sizeof(*dlm), GFP_KERNEL);
1972         if (!dlm) {
1973                 mlog_errno(-ENOMEM);
1974                 goto leave;
1975         }
1976 
1977         dlm->name = kstrdup(domain, GFP_KERNEL);
1978         if (dlm->name == NULL) {
1979                 mlog_errno(-ENOMEM);
1980                 kfree(dlm);
1981                 dlm = NULL;
1982                 goto leave;
1983         }
1984 
1985         dlm->lockres_hash = (struct hlist_head **)dlm_alloc_pagevec(DLM_HASH_PAGES);
1986         if (!dlm->lockres_hash) {
1987                 mlog_errno(-ENOMEM);
1988                 kfree(dlm->name);
1989                 kfree(dlm);
1990                 dlm = NULL;
1991                 goto leave;
1992         }
1993 
1994         for (i = 0; i < DLM_HASH_BUCKETS; i++)
1995                 INIT_HLIST_HEAD(dlm_lockres_hash(dlm, i));
1996 
1997         dlm->master_hash = (struct hlist_head **)
1998                                 dlm_alloc_pagevec(DLM_HASH_PAGES);
1999         if (!dlm->master_hash) {
2000                 mlog_errno(-ENOMEM);
2001                 dlm_free_pagevec((void **)dlm->lockres_hash, DLM_HASH_PAGES);
2002                 kfree(dlm->name);
2003                 kfree(dlm);
2004                 dlm = NULL;
2005                 goto leave;
2006         }
2007 
2008         for (i = 0; i < DLM_HASH_BUCKETS; i++)
2009                 INIT_HLIST_HEAD(dlm_master_hash(dlm, i));
2010 
2011         dlm->key = key;
2012         dlm->node_num = o2nm_this_node();
2013 
2014         ret = dlm_create_debugfs_subroot(dlm);
2015         if (ret < 0) {
2016                 dlm_free_pagevec((void **)dlm->master_hash, DLM_HASH_PAGES);
2017                 dlm_free_pagevec((void **)dlm->lockres_hash, DLM_HASH_PAGES);
2018                 kfree(dlm->name);
2019                 kfree(dlm);
2020                 dlm = NULL;
2021                 goto leave;
2022         }
2023 
2024         spin_lock_init(&dlm->spinlock);
2025         spin_lock_init(&dlm->master_lock);
2026         spin_lock_init(&dlm->ast_lock);
2027         spin_lock_init(&dlm->track_lock);
2028         INIT_LIST_HEAD(&dlm->list);
2029         INIT_LIST_HEAD(&dlm->dirty_list);
2030         INIT_LIST_HEAD(&dlm->reco.resources);
2031         INIT_LIST_HEAD(&dlm->reco.received);
2032         INIT_LIST_HEAD(&dlm->reco.node_data);
2033         INIT_LIST_HEAD(&dlm->purge_list);
2034         INIT_LIST_HEAD(&dlm->dlm_domain_handlers);
2035         INIT_LIST_HEAD(&dlm->tracking_list);
2036         dlm->reco.state = 0;
2037 
2038         INIT_LIST_HEAD(&dlm->pending_asts);
2039         INIT_LIST_HEAD(&dlm->pending_basts);
2040 
2041         mlog(0, "dlm->recovery_map=%p, &(dlm->recovery_map[0])=%p\n",
2042                   dlm->recovery_map, &(dlm->recovery_map[0]));
2043 
2044         memset(dlm->recovery_map, 0, sizeof(dlm->recovery_map));
2045         memset(dlm->live_nodes_map, 0, sizeof(dlm->live_nodes_map));
2046         memset(dlm->domain_map, 0, sizeof(dlm->domain_map));
2047 
2048         dlm->dlm_thread_task = NULL;
2049         dlm->dlm_reco_thread_task = NULL;
2050         dlm->dlm_worker = NULL;
2051         init_waitqueue_head(&dlm->dlm_thread_wq);
2052         init_waitqueue_head(&dlm->dlm_reco_thread_wq);
2053         init_waitqueue_head(&dlm->reco.event);
2054         init_waitqueue_head(&dlm->ast_wq);
2055         init_waitqueue_head(&dlm->migration_wq);
2056         INIT_LIST_HEAD(&dlm->mle_hb_events);
2057 
2058         dlm->joining_node = DLM_LOCK_RES_OWNER_UNKNOWN;
2059         init_waitqueue_head(&dlm->dlm_join_events);
2060 
2061         dlm->reco.new_master = O2NM_INVALID_NODE_NUM;
2062         dlm->reco.dead_node = O2NM_INVALID_NODE_NUM;
2063 
2064         atomic_set(&dlm->res_tot_count, 0);
2065         atomic_set(&dlm->res_cur_count, 0);
2066         for (i = 0; i < DLM_MLE_NUM_TYPES; ++i) {
2067                 atomic_set(&dlm->mle_tot_count[i], 0);
2068                 atomic_set(&dlm->mle_cur_count[i], 0);
2069         }
2070 
2071         spin_lock_init(&dlm->work_lock);
2072         INIT_LIST_HEAD(&dlm->work_list);
2073         INIT_WORK(&dlm->dispatched_work, dlm_dispatch_work);
2074 
2075         kref_init(&dlm->dlm_refs);
2076         dlm->dlm_state = DLM_CTXT_NEW;
2077 
2078         INIT_LIST_HEAD(&dlm->dlm_eviction_callbacks);
2079 
2080         mlog(0, "context init: refcount %u\n",
2081                   atomic_read(&dlm->dlm_refs.refcount));
2082 
2083 leave:
2084         return dlm;
2085 }
2086 
2087 /*
2088  * Compare a requested locking protocol version against the current one.
2089  *
2090  * If the major numbers are different, they are incompatible.
2091  * If the current minor is greater than the request, they are incompatible.
2092  * If the current minor is less than or equal to the request, they are
2093  * compatible, and the requester should run at the current minor version.
2094  */
2095 static int dlm_protocol_compare(struct dlm_protocol_version *existing,
2096                                 struct dlm_protocol_version *request)
2097 {
2098         if (existing->pv_major != request->pv_major)
2099                 return 1;
2100 
2101         if (existing->pv_minor > request->pv_minor)
2102                 return 1;
2103 
2104         if (existing->pv_minor < request->pv_minor)
2105                 request->pv_minor = existing->pv_minor;
2106 
2107         return 0;
2108 }
2109 
2110 /*
2111  * dlm_register_domain: one-time setup per "domain".
2112  *
2113  * The filesystem passes in the requested locking version via proto.
2114  * If registration was successful, proto will contain the negotiated
2115  * locking protocol.
2116  */
2117 struct dlm_ctxt * dlm_register_domain(const char *domain,
2118                                u32 key,
2119                                struct dlm_protocol_version *fs_proto)
2120 {
2121         int ret;
2122         struct dlm_ctxt *dlm = NULL;
2123         struct dlm_ctxt *new_ctxt = NULL;
2124 
2125         if (strlen(domain) >= O2NM_MAX_NAME_LEN) {
2126                 ret = -ENAMETOOLONG;
2127                 mlog(ML_ERROR, "domain name length too long\n");
2128                 goto leave;
2129         }
2130 
2131         mlog(0, "register called for domain \"%s\"\n", domain);
2132 
2133 retry:
2134         dlm = NULL;
2135         if (signal_pending(current)) {
2136                 ret = -ERESTARTSYS;
2137                 mlog_errno(ret);
2138                 goto leave;
2139         }
2140 
2141         spin_lock(&dlm_domain_lock);
2142 
2143         dlm = __dlm_lookup_domain(domain);
2144         if (dlm) {
2145                 if (dlm->dlm_state != DLM_CTXT_JOINED) {
2146                         spin_unlock(&dlm_domain_lock);
2147 
2148                         mlog(0, "This ctxt is not joined yet!\n");
2149                         wait_event_interruptible(dlm_domain_events,
2150                                                  dlm_wait_on_domain_helper(
2151                                                          domain));
2152                         goto retry;
2153                 }
2154 
2155                 if (dlm_protocol_compare(&dlm->fs_locking_proto, fs_proto)) {
2156                         spin_unlock(&dlm_domain_lock);
2157                         mlog(ML_ERROR,
2158                              "Requested locking protocol version is not "
2159                              "compatible with already registered domain "
2160                              "\"%s\"\n", domain);
2161                         ret = -EPROTO;
2162                         goto leave;
2163                 }
2164 
2165                 __dlm_get(dlm);
2166                 dlm->num_joins++;
2167 
2168                 spin_unlock(&dlm_domain_lock);
2169 
2170                 ret = 0;
2171                 goto leave;
2172         }
2173 
2174         /* doesn't exist */
2175         if (!new_ctxt) {
2176                 spin_unlock(&dlm_domain_lock);
2177 
2178                 new_ctxt = dlm_alloc_ctxt(domain, key);
2179                 if (new_ctxt)
2180                         goto retry;
2181 
2182                 ret = -ENOMEM;
2183                 mlog_errno(ret);
2184                 goto leave;
2185         }
2186 
2187         /* a little variable switch-a-roo here... */
2188         dlm = new_ctxt;
2189         new_ctxt = NULL;
2190 
2191         /* add the new domain */
2192         list_add_tail(&dlm->list, &dlm_domains);
2193         spin_unlock(&dlm_domain_lock);
2194 
2195         /*
2196          * Pass the locking protocol version into the join.  If the join
2197          * succeeds, it will have the negotiated protocol set.
2198          */
2199         dlm->dlm_locking_proto = dlm_protocol;
2200         dlm->fs_locking_proto = *fs_proto;
2201 
2202         ret = dlm_join_domain(dlm);
2203         if (ret) {
2204                 mlog_errno(ret);
2205                 dlm_put(dlm);
2206                 goto leave;
2207         }
2208 
2209         /* Tell the caller what locking protocol we negotiated */
2210         *fs_proto = dlm->fs_locking_proto;
2211 
2212         ret = 0;
2213 leave:
2214         if (new_ctxt)
2215                 dlm_free_ctxt_mem(new_ctxt);
2216 
2217         if (ret < 0)
2218                 dlm = ERR_PTR(ret);
2219 
2220         return dlm;
2221 }
2222 EXPORT_SYMBOL_GPL(dlm_register_domain);
2223 
2224 static LIST_HEAD(dlm_join_handlers);
2225 
2226 static void dlm_unregister_net_handlers(void)
2227 {
2228         o2net_unregister_handler_list(&dlm_join_handlers);
2229 }
2230 
2231 static int dlm_register_net_handlers(void)
2232 {
2233         int status = 0;
2234 
2235         status = o2net_register_handler(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY,
2236                                         sizeof(struct dlm_query_join_request),
2237                                         dlm_query_join_handler,
2238                                         NULL, NULL, &dlm_join_handlers);
2239         if (status)
2240                 goto bail;
2241 
2242         status = o2net_register_handler(DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
2243                                         sizeof(struct dlm_assert_joined),
2244                                         dlm_assert_joined_handler,
2245                                         NULL, NULL, &dlm_join_handlers);
2246         if (status)
2247                 goto bail;
2248 
2249         status = o2net_register_handler(DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
2250                                         sizeof(struct dlm_cancel_join),
2251                                         dlm_cancel_join_handler,
2252                                         NULL, NULL, &dlm_join_handlers);
2253         if (status)
2254                 goto bail;
2255 
2256         status = o2net_register_handler(DLM_QUERY_REGION, DLM_MOD_KEY,
2257                                         sizeof(struct dlm_query_region),
2258                                         dlm_query_region_handler,
2259                                         NULL, NULL, &dlm_join_handlers);
2260 
2261         if (status)
2262                 goto bail;
2263 
2264         status = o2net_register_handler(DLM_QUERY_NODEINFO, DLM_MOD_KEY,
2265                                         sizeof(struct dlm_query_nodeinfo),
2266                                         dlm_query_nodeinfo_handler,
2267                                         NULL, NULL, &dlm_join_handlers);
2268 bail:
2269         if (status < 0)
2270                 dlm_unregister_net_handlers();
2271 
2272         return status;
2273 }
2274 
2275 /* Domain eviction callback handling.
2276  *
2277  * The file system requires notification of node death *before* the
2278  * dlm completes it's recovery work, otherwise it may be able to
2279  * acquire locks on resources requiring recovery. Since the dlm can
2280  * evict a node from it's domain *before* heartbeat fires, a similar
2281  * mechanism is required. */
2282 
2283 /* Eviction is not expected to happen often, so a per-domain lock is
2284  * not necessary. Eviction callbacks are allowed to sleep for short
2285  * periods of time. */
2286 static DECLARE_RWSEM(dlm_callback_sem);
2287 
2288 void dlm_fire_domain_eviction_callbacks(struct dlm_ctxt *dlm,
2289                                         int node_num)
2290 {
2291         struct dlm_eviction_cb *cb;
2292 
2293         down_read(&dlm_callback_sem);
2294         list_for_each_entry(cb, &dlm->dlm_eviction_callbacks, ec_item) {
2295                 cb->ec_func(node_num, cb->ec_data);
2296         }
2297         up_read(&dlm_callback_sem);
2298 }
2299 
2300 void dlm_setup_eviction_cb(struct dlm_eviction_cb *cb,
2301                            dlm_eviction_func *f,
2302                            void *data)
2303 {
2304         INIT_LIST_HEAD(&cb->ec_item);
2305         cb->ec_func = f;
2306         cb->ec_data = data;
2307 }
2308 EXPORT_SYMBOL_GPL(dlm_setup_eviction_cb);
2309 
2310 void dlm_register_eviction_cb(struct dlm_ctxt *dlm,
2311                               struct dlm_eviction_cb *cb)
2312 {
2313         down_write(&dlm_callback_sem);
2314         list_add_tail(&cb->ec_item, &dlm->dlm_eviction_callbacks);
2315         up_write(&dlm_callback_sem);
2316 }
2317 EXPORT_SYMBOL_GPL(dlm_register_eviction_cb);
2318 
2319 void dlm_unregister_eviction_cb(struct dlm_eviction_cb *cb)
2320 {
2321         down_write(&dlm_callback_sem);
2322         list_del_init(&cb->ec_item);
2323         up_write(&dlm_callback_sem);
2324 }
2325 EXPORT_SYMBOL_GPL(dlm_unregister_eviction_cb);
2326 
2327 static int __init dlm_init(void)
2328 {
2329         int status;
2330 
2331         dlm_print_version();
2332 
2333         status = dlm_init_mle_cache();
2334         if (status) {
2335                 mlog(ML_ERROR, "Could not create o2dlm_mle slabcache\n");
2336                 goto error;
2337         }
2338 
2339         status = dlm_init_master_caches();
2340         if (status) {
2341                 mlog(ML_ERROR, "Could not create o2dlm_lockres and "
2342                      "o2dlm_lockname slabcaches\n");
2343                 goto error;
2344         }
2345 
2346         status = dlm_init_lock_cache();
2347         if (status) {
2348                 mlog(ML_ERROR, "Count not create o2dlm_lock slabcache\n");
2349                 goto error;
2350         }
2351 
2352         status = dlm_register_net_handlers();
2353         if (status) {
2354                 mlog(ML_ERROR, "Unable to register network handlers\n");
2355                 goto error;
2356         }
2357 
2358         status = dlm_create_debugfs_root();
2359         if (status)
2360                 goto error;
2361 
2362         return 0;
2363 error:
2364         dlm_unregister_net_handlers();
2365         dlm_destroy_lock_cache();
2366         dlm_destroy_master_caches();
2367         dlm_destroy_mle_cache();
2368         return -1;
2369 }
2370 
2371 static void __exit dlm_exit (void)
2372 {
2373         dlm_destroy_debugfs_root();
2374         dlm_unregister_net_handlers();
2375         dlm_destroy_lock_cache();
2376         dlm_destroy_master_caches();
2377         dlm_destroy_mle_cache();
2378 }
2379 
2380 MODULE_AUTHOR("Oracle");
2381 MODULE_LICENSE("GPL");
2382 
2383 module_init(dlm_init);
2384 module_exit(dlm_exit);
2385 

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