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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 #define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_DOMAIN)
 47 #include "cluster/masklog.h"
 48 
 49 /*
 50  * ocfs2 node maps are array of long int, which limits to send them freely
 51  * across the wire due to endianness issues. To workaround this, we convert
 52  * long ints to byte arrays. Following 3 routines are helper functions to
 53  * set/test/copy bits within those array of bytes
 54  */
 55 static inline void byte_set_bit(u8 nr, u8 map[])
 56 {
 57         map[nr >> 3] |= (1UL << (nr & 7));
 58 }
 59 
 60 static inline int byte_test_bit(u8 nr, u8 map[])
 61 {
 62         return ((1UL << (nr & 7)) & (map[nr >> 3])) != 0;
 63 }
 64 
 65 static inline void byte_copymap(u8 dmap[], unsigned long smap[],
 66                         unsigned int sz)
 67 {
 68         unsigned int nn;
 69 
 70         if (!sz)
 71                 return;
 72 
 73         memset(dmap, 0, ((sz + 7) >> 3));
 74         for (nn = 0 ; nn < sz; nn++)
 75                 if (test_bit(nn, smap))
 76                         byte_set_bit(nn, dmap);
 77 }
 78 
 79 static void dlm_free_pagevec(void **vec, int pages)
 80 {
 81         while (pages--)
 82                 free_page((unsigned long)vec[pages]);
 83         kfree(vec);
 84 }
 85 
 86 static void **dlm_alloc_pagevec(int pages)
 87 {
 88         void **vec = kmalloc(pages * sizeof(void *), GFP_KERNEL);
 89         int i;
 90 
 91         if (!vec)
 92                 return NULL;
 93 
 94         for (i = 0; i < pages; i++)
 95                 if (!(vec[i] = (void *)__get_free_page(GFP_KERNEL)))
 96                         goto out_free;
 97 
 98         mlog(0, "Allocated DLM hash pagevec; %d pages (%lu expected), %lu buckets per page\n",
 99              pages, (unsigned long)DLM_HASH_PAGES,
100              (unsigned long)DLM_BUCKETS_PER_PAGE);
101         return vec;
102 out_free:
103         dlm_free_pagevec(vec, i);
104         return NULL;
105 }
106 
107 /*
108  *
109  * spinlock lock ordering: if multiple locks are needed, obey this ordering:
110  *    dlm_domain_lock
111  *    struct dlm_ctxt->spinlock
112  *    struct dlm_lock_resource->spinlock
113  *    struct dlm_ctxt->master_lock
114  *    struct dlm_ctxt->ast_lock
115  *    dlm_master_list_entry->spinlock
116  *    dlm_lock->spinlock
117  *
118  */
119 
120 DEFINE_SPINLOCK(dlm_domain_lock);
121 LIST_HEAD(dlm_domains);
122 static DECLARE_WAIT_QUEUE_HEAD(dlm_domain_events);
123 
124 /*
125  * The supported protocol version for DLM communication.  Running domains
126  * will have a negotiated version with the same major number and a minor
127  * number equal or smaller.  The dlm_ctxt->dlm_locking_proto field should
128  * be used to determine what a running domain is actually using.
129  *
130  * New in version 1.1:
131  *      - Message DLM_QUERY_REGION added to support global heartbeat
132  *      - Message DLM_QUERY_NODEINFO added to allow online node removes
133  * New in version 1.2:
134  *      - Message DLM_BEGIN_EXIT_DOMAIN_MSG added to mark start of exit domain
135  */
136 static const struct dlm_protocol_version dlm_protocol = {
137         .pv_major = 1,
138         .pv_minor = 2,
139 };
140 
141 #define DLM_DOMAIN_BACKOFF_MS 200
142 
143 static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
144                                   void **ret_data);
145 static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data,
146                                      void **ret_data);
147 static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data,
148                                    void **ret_data);
149 static int dlm_query_region_handler(struct o2net_msg *msg, u32 len,
150                                     void *data, void **ret_data);
151 static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data,
152                                    void **ret_data);
153 static int dlm_protocol_compare(struct dlm_protocol_version *existing,
154                                 struct dlm_protocol_version *request);
155 
156 static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm);
157 
158 void __dlm_unhash_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
159 {
160         if (hlist_unhashed(&res->hash_node))
161                 return;
162 
163         mlog(0, "%s: Unhash res %.*s\n", dlm->name, res->lockname.len,
164              res->lockname.name);
165         hlist_del_init(&res->hash_node);
166         dlm_lockres_put(res);
167 }
168 
169 void __dlm_insert_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
170 {
171         struct hlist_head *bucket;
172         struct qstr *q;
173 
174         assert_spin_locked(&dlm->spinlock);
175 
176         q = &res->lockname;
177         bucket = dlm_lockres_hash(dlm, q->hash);
178 
179         /* get a reference for our hashtable */
180         dlm_lockres_get(res);
181 
182         hlist_add_head(&res->hash_node, bucket);
183 
184         mlog(0, "%s: Hash res %.*s\n", dlm->name, res->lockname.len,
185              res->lockname.name);
186 }
187 
188 struct dlm_lock_resource * __dlm_lookup_lockres_full(struct dlm_ctxt *dlm,
189                                                      const char *name,
190                                                      unsigned int len,
191                                                      unsigned int hash)
192 {
193         struct hlist_head *bucket;
194         struct dlm_lock_resource *res;
195 
196         mlog(0, "%.*s\n", len, name);
197 
198         assert_spin_locked(&dlm->spinlock);
199 
200         bucket = dlm_lockres_hash(dlm, hash);
201 
202         hlist_for_each_entry(res, bucket, hash_node) {
203                 if (res->lockname.name[0] != name[0])
204                         continue;
205                 if (unlikely(res->lockname.len != len))
206                         continue;
207                 if (memcmp(res->lockname.name + 1, name + 1, len - 1))
208                         continue;
209                 dlm_lockres_get(res);
210                 return res;
211         }
212         return NULL;
213 }
214 
215 /* intended to be called by functions which do not care about lock
216  * resources which are being purged (most net _handler functions).
217  * this will return NULL for any lock resource which is found but
218  * currently in the process of dropping its mastery reference.
219  * use __dlm_lookup_lockres_full when you need the lock resource
220  * regardless (e.g. dlm_get_lock_resource) */
221 struct dlm_lock_resource * __dlm_lookup_lockres(struct dlm_ctxt *dlm,
222                                                 const char *name,
223                                                 unsigned int len,
224                                                 unsigned int hash)
225 {
226         struct dlm_lock_resource *res = NULL;
227 
228         mlog(0, "%.*s\n", len, name);
229 
230         assert_spin_locked(&dlm->spinlock);
231 
232         res = __dlm_lookup_lockres_full(dlm, name, len, hash);
233         if (res) {
234                 spin_lock(&res->spinlock);
235                 if (res->state & DLM_LOCK_RES_DROPPING_REF) {
236                         spin_unlock(&res->spinlock);
237                         dlm_lockres_put(res);
238                         return NULL;
239                 }
240                 spin_unlock(&res->spinlock);
241         }
242 
243         return res;
244 }
245 
246 struct dlm_lock_resource * dlm_lookup_lockres(struct dlm_ctxt *dlm,
247                                     const char *name,
248                                     unsigned int len)
249 {
250         struct dlm_lock_resource *res;
251         unsigned int hash = dlm_lockid_hash(name, len);
252 
253         spin_lock(&dlm->spinlock);
254         res = __dlm_lookup_lockres(dlm, name, len, hash);
255         spin_unlock(&dlm->spinlock);
256         return res;
257 }
258 
259 static struct dlm_ctxt * __dlm_lookup_domain_full(const char *domain, int len)
260 {
261         struct dlm_ctxt *tmp;
262 
263         assert_spin_locked(&dlm_domain_lock);
264 
265         /* tmp->name here is always NULL terminated,
266          * but domain may not be! */
267         list_for_each_entry(tmp, &dlm_domains, list) {
268                 if (strlen(tmp->name) == len &&
269                     memcmp(tmp->name, domain, len)==0)
270                         return tmp;
271         }
272 
273         return NULL;
274 }
275 
276 /* For null terminated domain strings ONLY */
277 static struct dlm_ctxt * __dlm_lookup_domain(const char *domain)
278 {
279         assert_spin_locked(&dlm_domain_lock);
280 
281         return __dlm_lookup_domain_full(domain, strlen(domain));
282 }
283 
284 
285 /* returns true on one of two conditions:
286  * 1) the domain does not exist
287  * 2) the domain exists and it's state is "joined" */
288 static int dlm_wait_on_domain_helper(const char *domain)
289 {
290         int ret = 0;
291         struct dlm_ctxt *tmp = NULL;
292 
293         spin_lock(&dlm_domain_lock);
294 
295         tmp = __dlm_lookup_domain(domain);
296         if (!tmp)
297                 ret = 1;
298         else if (tmp->dlm_state == DLM_CTXT_JOINED)
299                 ret = 1;
300 
301         spin_unlock(&dlm_domain_lock);
302         return ret;
303 }
304 
305 static void dlm_free_ctxt_mem(struct dlm_ctxt *dlm)
306 {
307         dlm_destroy_debugfs_subroot(dlm);
308 
309         if (dlm->lockres_hash)
310                 dlm_free_pagevec((void **)dlm->lockres_hash, DLM_HASH_PAGES);
311 
312         if (dlm->master_hash)
313                 dlm_free_pagevec((void **)dlm->master_hash, DLM_HASH_PAGES);
314 
315         kfree(dlm->name);
316         kfree(dlm);
317 }
318 
319 /* A little strange - this function will be called while holding
320  * dlm_domain_lock and is expected to be holding it on the way out. We
321  * will however drop and reacquire it multiple times */
322 static void dlm_ctxt_release(struct kref *kref)
323 {
324         struct dlm_ctxt *dlm;
325 
326         dlm = container_of(kref, struct dlm_ctxt, dlm_refs);
327 
328         BUG_ON(dlm->num_joins);
329         BUG_ON(dlm->dlm_state == DLM_CTXT_JOINED);
330 
331         /* we may still be in the list if we hit an error during join. */
332         list_del_init(&dlm->list);
333 
334         spin_unlock(&dlm_domain_lock);
335 
336         mlog(0, "freeing memory from domain %s\n", dlm->name);
337 
338         wake_up(&dlm_domain_events);
339 
340         dlm_free_ctxt_mem(dlm);
341 
342         spin_lock(&dlm_domain_lock);
343 }
344 
345 void dlm_put(struct dlm_ctxt *dlm)
346 {
347         spin_lock(&dlm_domain_lock);
348         kref_put(&dlm->dlm_refs, dlm_ctxt_release);
349         spin_unlock(&dlm_domain_lock);
350 }
351 
352 static void __dlm_get(struct dlm_ctxt *dlm)
353 {
354         kref_get(&dlm->dlm_refs);
355 }
356 
357 /* given a questionable reference to a dlm object, gets a reference if
358  * it can find it in the list, otherwise returns NULL in which case
359  * you shouldn't trust your pointer. */
360 struct dlm_ctxt *dlm_grab(struct dlm_ctxt *dlm)
361 {
362         struct dlm_ctxt *target;
363         struct dlm_ctxt *ret = NULL;
364 
365         spin_lock(&dlm_domain_lock);
366 
367         list_for_each_entry(target, &dlm_domains, list) {
368                 if (target == dlm) {
369                         __dlm_get(target);
370                         ret = target;
371                         break;
372                 }
373         }
374 
375         spin_unlock(&dlm_domain_lock);
376 
377         return ret;
378 }
379 
380 int dlm_domain_fully_joined(struct dlm_ctxt *dlm)
381 {
382         int ret;
383 
384         spin_lock(&dlm_domain_lock);
385         ret = (dlm->dlm_state == DLM_CTXT_JOINED) ||
386                 (dlm->dlm_state == DLM_CTXT_IN_SHUTDOWN);
387         spin_unlock(&dlm_domain_lock);
388 
389         return ret;
390 }
391 
392 static void dlm_destroy_dlm_worker(struct dlm_ctxt *dlm)
393 {
394         if (dlm->dlm_worker) {
395                 flush_workqueue(dlm->dlm_worker);
396                 destroy_workqueue(dlm->dlm_worker);
397                 dlm->dlm_worker = NULL;
398         }
399 }
400 
401 static void dlm_complete_dlm_shutdown(struct dlm_ctxt *dlm)
402 {
403         dlm_unregister_domain_handlers(dlm);
404         dlm_debug_shutdown(dlm);
405         dlm_complete_thread(dlm);
406         dlm_complete_recovery_thread(dlm);
407         dlm_destroy_dlm_worker(dlm);
408 
409         /* We've left the domain. Now we can take ourselves out of the
410          * list and allow the kref stuff to help us free the
411          * memory. */
412         spin_lock(&dlm_domain_lock);
413         list_del_init(&dlm->list);
414         spin_unlock(&dlm_domain_lock);
415 
416         /* Wake up anyone waiting for us to remove this domain */
417         wake_up(&dlm_domain_events);
418 }
419 
420 static int dlm_migrate_all_locks(struct dlm_ctxt *dlm)
421 {
422         int i, num, n, ret = 0;
423         struct dlm_lock_resource *res;
424         struct hlist_node *iter;
425         struct hlist_head *bucket;
426         int dropped;
427 
428         mlog(0, "Migrating locks from domain %s\n", dlm->name);
429 
430         num = 0;
431         spin_lock(&dlm->spinlock);
432         for (i = 0; i < DLM_HASH_BUCKETS; i++) {
433 redo_bucket:
434                 n = 0;
435                 bucket = dlm_lockres_hash(dlm, i);
436                 iter = bucket->first;
437                 while (iter) {
438                         n++;
439                         res = hlist_entry(iter, struct dlm_lock_resource,
440                                           hash_node);
441                         dlm_lockres_get(res);
442                         /* migrate, if necessary.  this will drop the dlm
443                          * spinlock and retake it if it does migration. */
444                         dropped = dlm_empty_lockres(dlm, res);
445 
446                         spin_lock(&res->spinlock);
447                         if (dropped)
448                                 __dlm_lockres_calc_usage(dlm, res);
449                         else
450                                 iter = res->hash_node.next;
451                         spin_unlock(&res->spinlock);
452 
453                         dlm_lockres_put(res);
454 
455                         if (dropped) {
456                                 cond_resched_lock(&dlm->spinlock);
457                                 goto redo_bucket;
458                         }
459                 }
460                 cond_resched_lock(&dlm->spinlock);
461                 num += n;
462         }
463         spin_unlock(&dlm->spinlock);
464         wake_up(&dlm->dlm_thread_wq);
465 
466         /* let the dlm thread take care of purging, keep scanning until
467          * nothing remains in the hash */
468         if (num) {
469                 mlog(0, "%s: %d lock resources in hash last pass\n",
470                      dlm->name, num);
471                 ret = -EAGAIN;
472         }
473         mlog(0, "DONE Migrating locks from domain %s\n", dlm->name);
474         return ret;
475 }
476 
477 static int dlm_no_joining_node(struct dlm_ctxt *dlm)
478 {
479         int ret;
480 
481         spin_lock(&dlm->spinlock);
482         ret = dlm->joining_node == DLM_LOCK_RES_OWNER_UNKNOWN;
483         spin_unlock(&dlm->spinlock);
484 
485         return ret;
486 }
487 
488 static int dlm_begin_exit_domain_handler(struct o2net_msg *msg, u32 len,
489                                          void *data, void **ret_data)
490 {
491         struct dlm_ctxt *dlm = data;
492         unsigned int node;
493         struct dlm_exit_domain *exit_msg = (struct dlm_exit_domain *) msg->buf;
494 
495         if (!dlm_grab(dlm))
496                 return 0;
497 
498         node = exit_msg->node_idx;
499         mlog(0, "%s: Node %u sent a begin exit domain message\n", dlm->name, node);
500 
501         spin_lock(&dlm->spinlock);
502         set_bit(node, dlm->exit_domain_map);
503         spin_unlock(&dlm->spinlock);
504 
505         dlm_put(dlm);
506 
507         return 0;
508 }
509 
510 static void dlm_mark_domain_leaving(struct dlm_ctxt *dlm)
511 {
512         /* Yikes, a double spinlock! I need domain_lock for the dlm
513          * state and the dlm spinlock for join state... Sorry! */
514 again:
515         spin_lock(&dlm_domain_lock);
516         spin_lock(&dlm->spinlock);
517 
518         if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
519                 mlog(0, "Node %d is joining, we wait on it.\n",
520                           dlm->joining_node);
521                 spin_unlock(&dlm->spinlock);
522                 spin_unlock(&dlm_domain_lock);
523 
524                 wait_event(dlm->dlm_join_events, dlm_no_joining_node(dlm));
525                 goto again;
526         }
527 
528         dlm->dlm_state = DLM_CTXT_LEAVING;
529         spin_unlock(&dlm->spinlock);
530         spin_unlock(&dlm_domain_lock);
531 }
532 
533 static void __dlm_print_nodes(struct dlm_ctxt *dlm)
534 {
535         int node = -1, num = 0;
536 
537         assert_spin_locked(&dlm->spinlock);
538 
539         printk("( ");
540         while ((node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES,
541                                      node + 1)) < O2NM_MAX_NODES) {
542                 printk("%d ", node);
543                 ++num;
544         }
545         printk(") %u nodes\n", num);
546 }
547 
548 static int dlm_exit_domain_handler(struct o2net_msg *msg, u32 len, void *data,
549                                    void **ret_data)
550 {
551         struct dlm_ctxt *dlm = data;
552         unsigned int node;
553         struct dlm_exit_domain *exit_msg = (struct dlm_exit_domain *) msg->buf;
554 
555         mlog(0, "%p %u %p", msg, len, data);
556 
557         if (!dlm_grab(dlm))
558                 return 0;
559 
560         node = exit_msg->node_idx;
561 
562         spin_lock(&dlm->spinlock);
563         clear_bit(node, dlm->domain_map);
564         clear_bit(node, dlm->exit_domain_map);
565         printk(KERN_NOTICE "o2dlm: Node %u leaves domain %s ", node, dlm->name);
566         __dlm_print_nodes(dlm);
567 
568         /* notify anything attached to the heartbeat events */
569         dlm_hb_event_notify_attached(dlm, node, 0);
570 
571         spin_unlock(&dlm->spinlock);
572 
573         dlm_put(dlm);
574 
575         return 0;
576 }
577 
578 static int dlm_send_one_domain_exit(struct dlm_ctxt *dlm, u32 msg_type,
579                                     unsigned int node)
580 {
581         int status;
582         struct dlm_exit_domain leave_msg;
583 
584         mlog(0, "%s: Sending domain exit message %u to node %u\n", dlm->name,
585              msg_type, node);
586 
587         memset(&leave_msg, 0, sizeof(leave_msg));
588         leave_msg.node_idx = dlm->node_num;
589 
590         status = o2net_send_message(msg_type, dlm->key, &leave_msg,
591                                     sizeof(leave_msg), node, NULL);
592         if (status < 0)
593                 mlog(ML_ERROR, "Error %d sending domain exit message %u "
594                      "to node %u on domain %s\n", status, msg_type, node,
595                      dlm->name);
596 
597         return status;
598 }
599 
600 static void dlm_begin_exit_domain(struct dlm_ctxt *dlm)
601 {
602         int node = -1;
603 
604         /* Support for begin exit domain was added in 1.2 */
605         if (dlm->dlm_locking_proto.pv_major == 1 &&
606             dlm->dlm_locking_proto.pv_minor < 2)
607                 return;
608 
609         /*
610          * Unlike DLM_EXIT_DOMAIN_MSG, DLM_BEGIN_EXIT_DOMAIN_MSG is purely
611          * informational. Meaning if a node does not receive the message,
612          * so be it.
613          */
614         spin_lock(&dlm->spinlock);
615         while (1) {
616                 node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES, node + 1);
617                 if (node >= O2NM_MAX_NODES)
618                         break;
619                 if (node == dlm->node_num)
620                         continue;
621 
622                 spin_unlock(&dlm->spinlock);
623                 dlm_send_one_domain_exit(dlm, DLM_BEGIN_EXIT_DOMAIN_MSG, node);
624                 spin_lock(&dlm->spinlock);
625         }
626         spin_unlock(&dlm->spinlock);
627 }
628 
629 static void dlm_leave_domain(struct dlm_ctxt *dlm)
630 {
631         int node, clear_node, status;
632 
633         /* At this point we've migrated away all our locks and won't
634          * accept mastership of new ones. The dlm is responsible for
635          * almost nothing now. We make sure not to confuse any joining
636          * nodes and then commence shutdown procedure. */
637 
638         spin_lock(&dlm->spinlock);
639         /* Clear ourselves from the domain map */
640         clear_bit(dlm->node_num, dlm->domain_map);
641         while ((node = find_next_bit(dlm->domain_map, O2NM_MAX_NODES,
642                                      0)) < O2NM_MAX_NODES) {
643                 /* Drop the dlm spinlock. This is safe wrt the domain_map.
644                  * -nodes cannot be added now as the
645                  *   query_join_handlers knows to respond with OK_NO_MAP
646                  * -we catch the right network errors if a node is
647                  *   removed from the map while we're sending him the
648                  *   exit message. */
649                 spin_unlock(&dlm->spinlock);
650 
651                 clear_node = 1;
652 
653                 status = dlm_send_one_domain_exit(dlm, DLM_EXIT_DOMAIN_MSG,
654                                                   node);
655                 if (status < 0 &&
656                     status != -ENOPROTOOPT &&
657                     status != -ENOTCONN) {
658                         mlog(ML_NOTICE, "Error %d sending domain exit message "
659                              "to node %d\n", status, node);
660 
661                         /* Not sure what to do here but lets sleep for
662                          * a bit in case this was a transient
663                          * error... */
664                         msleep(DLM_DOMAIN_BACKOFF_MS);
665                         clear_node = 0;
666                 }
667 
668                 spin_lock(&dlm->spinlock);
669                 /* If we're not clearing the node bit then we intend
670                  * to loop back around to try again. */
671                 if (clear_node)
672                         clear_bit(node, dlm->domain_map);
673         }
674         spin_unlock(&dlm->spinlock);
675 }
676 
677 int dlm_shutting_down(struct dlm_ctxt *dlm)
678 {
679         int ret = 0;
680 
681         spin_lock(&dlm_domain_lock);
682 
683         if (dlm->dlm_state == DLM_CTXT_IN_SHUTDOWN)
684                 ret = 1;
685 
686         spin_unlock(&dlm_domain_lock);
687 
688         return ret;
689 }
690 
691 void dlm_unregister_domain(struct dlm_ctxt *dlm)
692 {
693         int leave = 0;
694         struct dlm_lock_resource *res;
695 
696         spin_lock(&dlm_domain_lock);
697         BUG_ON(dlm->dlm_state != DLM_CTXT_JOINED);
698         BUG_ON(!dlm->num_joins);
699 
700         dlm->num_joins--;
701         if (!dlm->num_joins) {
702                 /* We mark it "in shutdown" now so new register
703                  * requests wait until we've completely left the
704                  * domain. Don't use DLM_CTXT_LEAVING yet as we still
705                  * want new domain joins to communicate with us at
706                  * least until we've completed migration of our
707                  * resources. */
708                 dlm->dlm_state = DLM_CTXT_IN_SHUTDOWN;
709                 leave = 1;
710         }
711         spin_unlock(&dlm_domain_lock);
712 
713         if (leave) {
714                 mlog(0, "shutting down domain %s\n", dlm->name);
715                 dlm_begin_exit_domain(dlm);
716 
717                 /* We changed dlm state, notify the thread */
718                 dlm_kick_thread(dlm, NULL);
719 
720                 while (dlm_migrate_all_locks(dlm)) {
721                         /* Give dlm_thread time to purge the lockres' */
722                         msleep(500);
723                         mlog(0, "%s: more migration to do\n", dlm->name);
724                 }
725 
726                 /* This list should be empty. If not, print remaining lockres */
727                 if (!list_empty(&dlm->tracking_list)) {
728                         mlog(ML_ERROR, "Following lockres' are still on the "
729                              "tracking list:\n");
730                         list_for_each_entry(res, &dlm->tracking_list, tracking)
731                                 dlm_print_one_lock_resource(res);
732                 }
733 
734                 dlm_mark_domain_leaving(dlm);
735                 dlm_leave_domain(dlm);
736                 printk(KERN_NOTICE "o2dlm: Leaving domain %s\n", dlm->name);
737                 dlm_force_free_mles(dlm);
738                 dlm_complete_dlm_shutdown(dlm);
739         }
740         dlm_put(dlm);
741 }
742 EXPORT_SYMBOL_GPL(dlm_unregister_domain);
743 
744 static int dlm_query_join_proto_check(char *proto_type, int node,
745                                       struct dlm_protocol_version *ours,
746                                       struct dlm_protocol_version *request)
747 {
748         int rc;
749         struct dlm_protocol_version proto = *request;
750 
751         if (!dlm_protocol_compare(ours, &proto)) {
752                 mlog(0,
753                      "node %u wanted to join with %s locking protocol "
754                      "%u.%u, we respond with %u.%u\n",
755                      node, proto_type,
756                      request->pv_major,
757                      request->pv_minor,
758                      proto.pv_major, proto.pv_minor);
759                 request->pv_minor = proto.pv_minor;
760                 rc = 0;
761         } else {
762                 mlog(ML_NOTICE,
763                      "Node %u wanted to join with %s locking "
764                      "protocol %u.%u, but we have %u.%u, disallowing\n",
765                      node, proto_type,
766                      request->pv_major,
767                      request->pv_minor,
768                      ours->pv_major,
769                      ours->pv_minor);
770                 rc = 1;
771         }
772 
773         return rc;
774 }
775 
776 /*
777  * struct dlm_query_join_packet is made up of four one-byte fields.  They
778  * are effectively in big-endian order already.  However, little-endian
779  * machines swap them before putting the packet on the wire (because
780  * query_join's response is a status, and that status is treated as a u32
781  * on the wire).  Thus, a big-endian and little-endian machines will treat
782  * this structure differently.
783  *
784  * The solution is to have little-endian machines swap the structure when
785  * converting from the structure to the u32 representation.  This will
786  * result in the structure having the correct format on the wire no matter
787  * the host endian format.
788  */
789 static void dlm_query_join_packet_to_wire(struct dlm_query_join_packet *packet,
790                                           u32 *wire)
791 {
792         union dlm_query_join_response response;
793 
794         response.packet = *packet;
795         *wire = be32_to_cpu(response.intval);
796 }
797 
798 static void dlm_query_join_wire_to_packet(u32 wire,
799                                           struct dlm_query_join_packet *packet)
800 {
801         union dlm_query_join_response response;
802 
803         response.intval = cpu_to_be32(wire);
804         *packet = response.packet;
805 }
806 
807 static int dlm_query_join_handler(struct o2net_msg *msg, u32 len, void *data,
808                                   void **ret_data)
809 {
810         struct dlm_query_join_request *query;
811         struct dlm_query_join_packet packet = {
812                 .code = JOIN_DISALLOW,
813         };
814         struct dlm_ctxt *dlm = NULL;
815         u32 response;
816         u8 nodenum;
817 
818         query = (struct dlm_query_join_request *) msg->buf;
819 
820         mlog(0, "node %u wants to join domain %s\n", query->node_idx,
821                   query->domain);
822 
823         /*
824          * If heartbeat doesn't consider the node live, tell it
825          * to back off and try again.  This gives heartbeat a chance
826          * to catch up.
827          */
828         if (!o2hb_check_node_heartbeating_no_sem(query->node_idx)) {
829                 mlog(0, "node %u is not in our live map yet\n",
830                      query->node_idx);
831 
832                 packet.code = JOIN_DISALLOW;
833                 goto respond;
834         }
835 
836         packet.code = JOIN_OK_NO_MAP;
837 
838         spin_lock(&dlm_domain_lock);
839         dlm = __dlm_lookup_domain_full(query->domain, query->name_len);
840         if (!dlm)
841                 goto unlock_respond;
842 
843         /*
844          * There is a small window where the joining node may not see the
845          * node(s) that just left but still part of the cluster. DISALLOW
846          * join request if joining node has different node map.
847          */
848         nodenum=0;
849         while (nodenum < O2NM_MAX_NODES) {
850                 if (test_bit(nodenum, dlm->domain_map)) {
851                         if (!byte_test_bit(nodenum, query->node_map)) {
852                                 mlog(0, "disallow join as node %u does not "
853                                      "have node %u in its nodemap\n",
854                                      query->node_idx, nodenum);
855                                 packet.code = JOIN_DISALLOW;
856                                 goto unlock_respond;
857                         }
858                 }
859                 nodenum++;
860         }
861 
862         /* Once the dlm ctxt is marked as leaving then we don't want
863          * to be put in someone's domain map.
864          * Also, explicitly disallow joining at certain troublesome
865          * times (ie. during recovery). */
866         if (dlm->dlm_state != DLM_CTXT_LEAVING) {
867                 int bit = query->node_idx;
868                 spin_lock(&dlm->spinlock);
869 
870                 if (dlm->dlm_state == DLM_CTXT_NEW &&
871                     dlm->joining_node == DLM_LOCK_RES_OWNER_UNKNOWN) {
872                         /*If this is a brand new context and we
873                          * haven't started our join process yet, then
874                          * the other node won the race. */
875                         packet.code = JOIN_OK_NO_MAP;
876                 } else if (dlm->joining_node != DLM_LOCK_RES_OWNER_UNKNOWN) {
877                         /* Disallow parallel joins. */
878                         packet.code = JOIN_DISALLOW;
879                 } else if (dlm->reco.state & DLM_RECO_STATE_ACTIVE) {
880                         mlog(0, "node %u trying to join, but recovery "
881                              "is ongoing.\n", bit);
882                         packet.code = JOIN_DISALLOW;
883                 } else if (test_bit(bit, dlm->recovery_map)) {
884                         mlog(0, "node %u trying to join, but it "
885                              "still needs recovery.\n", bit);
886                         packet.code = JOIN_DISALLOW;
887                 } else if (test_bit(bit, dlm->domain_map)) {
888                         mlog(0, "node %u trying to join, but it "
889                              "is still in the domain! needs recovery?\n",
890                              bit);
891                         packet.code = JOIN_DISALLOW;
892                 } else {
893                         /* Alright we're fully a part of this domain
894                          * so we keep some state as to who's joining
895                          * and indicate to him that needs to be fixed
896                          * up. */
897 
898                         /* Make sure we speak compatible locking protocols.  */
899                         if (dlm_query_join_proto_check("DLM", bit,
900                                                        &dlm->dlm_locking_proto,
901                                                        &query->dlm_proto)) {
902                                 packet.code = JOIN_PROTOCOL_MISMATCH;
903                         } else if (dlm_query_join_proto_check("fs", bit,
904                                                               &dlm->fs_locking_proto,
905                                                               &query->fs_proto)) {
906                                 packet.code = JOIN_PROTOCOL_MISMATCH;
907                         } else {
908                                 packet.dlm_minor = query->dlm_proto.pv_minor;
909                                 packet.fs_minor = query->fs_proto.pv_minor;
910                                 packet.code = JOIN_OK;
911                                 __dlm_set_joining_node(dlm, query->node_idx);
912                         }
913                 }
914 
915                 spin_unlock(&dlm->spinlock);
916         }
917 unlock_respond:
918         spin_unlock(&dlm_domain_lock);
919 
920 respond:
921         mlog(0, "We respond with %u\n", packet.code);
922 
923         dlm_query_join_packet_to_wire(&packet, &response);
924         return response;
925 }
926 
927 static int dlm_assert_joined_handler(struct o2net_msg *msg, u32 len, void *data,
928                                      void **ret_data)
929 {
930         struct dlm_assert_joined *assert;
931         struct dlm_ctxt *dlm = NULL;
932 
933         assert = (struct dlm_assert_joined *) msg->buf;
934 
935         mlog(0, "node %u asserts join on domain %s\n", assert->node_idx,
936                   assert->domain);
937 
938         spin_lock(&dlm_domain_lock);
939         dlm = __dlm_lookup_domain_full(assert->domain, assert->name_len);
940         /* XXX should we consider no dlm ctxt an error? */
941         if (dlm) {
942                 spin_lock(&dlm->spinlock);
943 
944                 /* Alright, this node has officially joined our
945                  * domain. Set him in the map and clean up our
946                  * leftover join state. */
947                 BUG_ON(dlm->joining_node != assert->node_idx);
948 
949                 if (dlm->reco.state & DLM_RECO_STATE_ACTIVE) {
950                         mlog(0, "dlm recovery is ongoing, disallow join\n");
951                         spin_unlock(&dlm->spinlock);
952                         spin_unlock(&dlm_domain_lock);
953                         return -EAGAIN;
954                 }
955 
956                 set_bit(assert->node_idx, dlm->domain_map);
957                 clear_bit(assert->node_idx, dlm->exit_domain_map);
958                 __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
959 
960                 printk(KERN_NOTICE "o2dlm: Node %u joins domain %s ",
961                        assert->node_idx, dlm->name);
962                 __dlm_print_nodes(dlm);
963 
964                 /* notify anything attached to the heartbeat events */
965                 dlm_hb_event_notify_attached(dlm, assert->node_idx, 1);
966 
967                 spin_unlock(&dlm->spinlock);
968         }
969         spin_unlock(&dlm_domain_lock);
970 
971         return 0;
972 }
973 
974 static int dlm_match_regions(struct dlm_ctxt *dlm,
975                              struct dlm_query_region *qr,
976                              char *local, int locallen)
977 {
978         char *remote = qr->qr_regions;
979         char *l, *r;
980         int localnr, i, j, foundit;
981         int status = 0;
982 
983         if (!o2hb_global_heartbeat_active()) {
984                 if (qr->qr_numregions) {
985                         mlog(ML_ERROR, "Domain %s: Joining node %d has global "
986                              "heartbeat enabled but local node %d does not\n",
987                              qr->qr_domain, qr->qr_node, dlm->node_num);
988                         status = -EINVAL;
989                 }
990                 goto bail;
991         }
992 
993         if (o2hb_global_heartbeat_active() && !qr->qr_numregions) {
994                 mlog(ML_ERROR, "Domain %s: Local node %d has global "
995                      "heartbeat enabled but joining node %d does not\n",
996                      qr->qr_domain, dlm->node_num, qr->qr_node);
997                 status = -EINVAL;
998                 goto bail;
999         }
1000 
1001         r = remote;
1002         for (i = 0; i < qr->qr_numregions; ++i) {
1003                 mlog(0, "Region %.*s\n", O2HB_MAX_REGION_NAME_LEN, r);
1004                 r += O2HB_MAX_REGION_NAME_LEN;
1005         }
1006 
1007         localnr = min(O2NM_MAX_REGIONS, locallen/O2HB_MAX_REGION_NAME_LEN);
1008         localnr = o2hb_get_all_regions(local, (u8)localnr);
1009 
1010         /* compare local regions with remote */
1011         l = local;
1012         for (i = 0; i < localnr; ++i) {
1013                 foundit = 0;
1014                 r = remote;
1015                 for (j = 0; j <= qr->qr_numregions; ++j) {
1016                         if (!memcmp(l, r, O2HB_MAX_REGION_NAME_LEN)) {
1017                                 foundit = 1;
1018                                 break;
1019                         }
1020                         r += O2HB_MAX_REGION_NAME_LEN;
1021                 }
1022                 if (!foundit) {
1023                         status = -EINVAL;
1024                         mlog(ML_ERROR, "Domain %s: Region '%.*s' registered "
1025                              "in local node %d but not in joining node %d\n",
1026                              qr->qr_domain, O2HB_MAX_REGION_NAME_LEN, l,
1027                              dlm->node_num, qr->qr_node);
1028                         goto bail;
1029                 }
1030                 l += O2HB_MAX_REGION_NAME_LEN;
1031         }
1032 
1033         /* compare remote with local regions */
1034         r = remote;
1035         for (i = 0; i < qr->qr_numregions; ++i) {
1036                 foundit = 0;
1037                 l = local;
1038                 for (j = 0; j < localnr; ++j) {
1039                         if (!memcmp(r, l, O2HB_MAX_REGION_NAME_LEN)) {
1040                                 foundit = 1;
1041                                 break;
1042                         }
1043                         l += O2HB_MAX_REGION_NAME_LEN;
1044                 }
1045                 if (!foundit) {
1046                         status = -EINVAL;
1047                         mlog(ML_ERROR, "Domain %s: Region '%.*s' registered "
1048                              "in joining node %d but not in local node %d\n",
1049                              qr->qr_domain, O2HB_MAX_REGION_NAME_LEN, r,
1050                              qr->qr_node, dlm->node_num);
1051                         goto bail;
1052                 }
1053                 r += O2HB_MAX_REGION_NAME_LEN;
1054         }
1055 
1056 bail:
1057         return status;
1058 }
1059 
1060 static int dlm_send_regions(struct dlm_ctxt *dlm, unsigned long *node_map)
1061 {
1062         struct dlm_query_region *qr = NULL;
1063         int status, ret = 0, i;
1064         char *p;
1065 
1066         if (find_next_bit(node_map, O2NM_MAX_NODES, 0) >= O2NM_MAX_NODES)
1067                 goto bail;
1068 
1069         qr = kzalloc(sizeof(struct dlm_query_region), GFP_KERNEL);
1070         if (!qr) {
1071                 ret = -ENOMEM;
1072                 mlog_errno(ret);
1073                 goto bail;
1074         }
1075 
1076         qr->qr_node = dlm->node_num;
1077         qr->qr_namelen = strlen(dlm->name);
1078         memcpy(qr->qr_domain, dlm->name, qr->qr_namelen);
1079         /* if local hb, the numregions will be zero */
1080         if (o2hb_global_heartbeat_active())
1081                 qr->qr_numregions = o2hb_get_all_regions(qr->qr_regions,
1082                                                          O2NM_MAX_REGIONS);
1083 
1084         p = qr->qr_regions;
1085         for (i = 0; i < qr->qr_numregions; ++i, p += O2HB_MAX_REGION_NAME_LEN)
1086                 mlog(0, "Region %.*s\n", O2HB_MAX_REGION_NAME_LEN, p);
1087 
1088         i = -1;
1089         while ((i = find_next_bit(node_map, O2NM_MAX_NODES,
1090                                   i + 1)) < O2NM_MAX_NODES) {
1091                 if (i == dlm->node_num)
1092                         continue;
1093 
1094                 mlog(0, "Sending regions to node %d\n", i);
1095 
1096                 ret = o2net_send_message(DLM_QUERY_REGION, DLM_MOD_KEY, qr,
1097                                          sizeof(struct dlm_query_region),
1098                                          i, &status);
1099                 if (ret >= 0)
1100                         ret = status;
1101                 if (ret) {
1102                         mlog(ML_ERROR, "Region mismatch %d, node %d\n",
1103                              ret, i);
1104                         break;
1105                 }
1106         }
1107 
1108 bail:
1109         kfree(qr);
1110         return ret;
1111 }
1112 
1113 static int dlm_query_region_handler(struct o2net_msg *msg, u32 len,
1114                                     void *data, void **ret_data)
1115 {
1116         struct dlm_query_region *qr;
1117         struct dlm_ctxt *dlm = NULL;
1118         char *local = NULL;
1119         int status = 0;
1120 
1121         qr = (struct dlm_query_region *) msg->buf;
1122 
1123         mlog(0, "Node %u queries hb regions on domain %s\n", qr->qr_node,
1124              qr->qr_domain);
1125 
1126         /* buffer used in dlm_mast_regions() */
1127         local = kmalloc(sizeof(qr->qr_regions), GFP_KERNEL);
1128         if (!local)
1129                 return -ENOMEM;
1130 
1131         status = -EINVAL;
1132 
1133         spin_lock(&dlm_domain_lock);
1134         dlm = __dlm_lookup_domain_full(qr->qr_domain, qr->qr_namelen);
1135         if (!dlm) {
1136                 mlog(ML_ERROR, "Node %d queried hb regions on domain %s "
1137                      "before join domain\n", qr->qr_node, qr->qr_domain);
1138                 goto out_domain_lock;
1139         }
1140 
1141         spin_lock(&dlm->spinlock);
1142         if (dlm->joining_node != qr->qr_node) {
1143                 mlog(ML_ERROR, "Node %d queried hb regions on domain %s "
1144                      "but joining node is %d\n", qr->qr_node, qr->qr_domain,
1145                      dlm->joining_node);
1146                 goto out_dlm_lock;
1147         }
1148 
1149         /* Support for global heartbeat was added in 1.1 */
1150         if (dlm->dlm_locking_proto.pv_major == 1 &&
1151             dlm->dlm_locking_proto.pv_minor == 0) {
1152                 mlog(ML_ERROR, "Node %d queried hb regions on domain %s "
1153                      "but active dlm protocol is %d.%d\n", qr->qr_node,
1154                      qr->qr_domain, dlm->dlm_locking_proto.pv_major,
1155                      dlm->dlm_locking_proto.pv_minor);
1156                 goto out_dlm_lock;
1157         }
1158 
1159         status = dlm_match_regions(dlm, qr, local, sizeof(qr->qr_regions));
1160 
1161 out_dlm_lock:
1162         spin_unlock(&dlm->spinlock);
1163 
1164 out_domain_lock:
1165         spin_unlock(&dlm_domain_lock);
1166 
1167         kfree(local);
1168 
1169         return status;
1170 }
1171 
1172 static int dlm_match_nodes(struct dlm_ctxt *dlm, struct dlm_query_nodeinfo *qn)
1173 {
1174         struct o2nm_node *local;
1175         struct dlm_node_info *remote;
1176         int i, j;
1177         int status = 0;
1178 
1179         for (j = 0; j < qn->qn_numnodes; ++j)
1180                 mlog(0, "Node %3d, %pI4:%u\n", qn->qn_nodes[j].ni_nodenum,
1181                      &(qn->qn_nodes[j].ni_ipv4_address),
1182                      ntohs(qn->qn_nodes[j].ni_ipv4_port));
1183 
1184         for (i = 0; i < O2NM_MAX_NODES && !status; ++i) {
1185                 local = o2nm_get_node_by_num(i);
1186                 remote = NULL;
1187                 for (j = 0; j < qn->qn_numnodes; ++j) {
1188                         if (qn->qn_nodes[j].ni_nodenum == i) {
1189                                 remote = &(qn->qn_nodes[j]);
1190                                 break;
1191                         }
1192                 }
1193 
1194                 if (!local && !remote)
1195                         continue;
1196 
1197                 if ((local && !remote) || (!local && remote))
1198                         status = -EINVAL;
1199 
1200                 if (!status &&
1201                     ((remote->ni_nodenum != local->nd_num) ||
1202                      (remote->ni_ipv4_port != local->nd_ipv4_port) ||
1203                      (remote->ni_ipv4_address != local->nd_ipv4_address)))
1204                         status = -EINVAL;
1205 
1206                 if (status) {
1207                         if (remote && !local)
1208                                 mlog(ML_ERROR, "Domain %s: Node %d (%pI4:%u) "
1209                                      "registered in joining node %d but not in "
1210                                      "local node %d\n", qn->qn_domain,
1211                                      remote->ni_nodenum,
1212                                      &(remote->ni_ipv4_address),
1213                                      ntohs(remote->ni_ipv4_port),
1214                                      qn->qn_nodenum, dlm->node_num);
1215                         if (local && !remote)
1216                                 mlog(ML_ERROR, "Domain %s: Node %d (%pI4:%u) "
1217                                      "registered in local node %d but not in "
1218                                      "joining node %d\n", qn->qn_domain,
1219                                      local->nd_num, &(local->nd_ipv4_address),
1220                                      ntohs(local->nd_ipv4_port),
1221                                      dlm->node_num, qn->qn_nodenum);
1222                         BUG_ON((!local && !remote));
1223                 }
1224 
1225                 if (local)
1226                         o2nm_node_put(local);
1227         }
1228 
1229         return status;
1230 }
1231 
1232 static int dlm_send_nodeinfo(struct dlm_ctxt *dlm, unsigned long *node_map)
1233 {
1234         struct dlm_query_nodeinfo *qn = NULL;
1235         struct o2nm_node *node;
1236         int ret = 0, status, count, i;
1237 
1238         if (find_next_bit(node_map, O2NM_MAX_NODES, 0) >= O2NM_MAX_NODES)
1239                 goto bail;
1240 
1241         qn = kzalloc(sizeof(struct dlm_query_nodeinfo), GFP_KERNEL);
1242         if (!qn) {
1243                 ret = -ENOMEM;
1244                 mlog_errno(ret);
1245                 goto bail;
1246         }
1247 
1248         for (i = 0, count = 0; i < O2NM_MAX_NODES; ++i) {
1249                 node = o2nm_get_node_by_num(i);
1250                 if (!node)
1251                         continue;
1252                 qn->qn_nodes[count].ni_nodenum = node->nd_num;
1253                 qn->qn_nodes[count].ni_ipv4_port = node->nd_ipv4_port;
1254                 qn->qn_nodes[count].ni_ipv4_address = node->nd_ipv4_address;
1255                 mlog(0, "Node %3d, %pI4:%u\n", node->nd_num,
1256                      &(node->nd_ipv4_address), ntohs(node->nd_ipv4_port));
1257                 ++count;
1258                 o2nm_node_put(node);
1259         }
1260 
1261         qn->qn_nodenum = dlm->node_num;
1262         qn->qn_numnodes = count;
1263         qn->qn_namelen = strlen(dlm->name);
1264         memcpy(qn->qn_domain, dlm->name, qn->qn_namelen);
1265 
1266         i = -1;
1267         while ((i = find_next_bit(node_map, O2NM_MAX_NODES,
1268                                   i + 1)) < O2NM_MAX_NODES) {
1269                 if (i == dlm->node_num)
1270                         continue;
1271 
1272                 mlog(0, "Sending nodeinfo to node %d\n", i);
1273 
1274                 ret = o2net_send_message(DLM_QUERY_NODEINFO, DLM_MOD_KEY,
1275                                          qn, sizeof(struct dlm_query_nodeinfo),
1276                                          i, &status);
1277                 if (ret >= 0)
1278                         ret = status;
1279                 if (ret) {
1280                         mlog(ML_ERROR, "node mismatch %d, node %d\n", ret, i);
1281                         break;
1282                 }
1283         }
1284 
1285 bail:
1286         kfree(qn);
1287         return ret;
1288 }
1289 
1290 static int dlm_query_nodeinfo_handler(struct o2net_msg *msg, u32 len,
1291                                       void *data, void **ret_data)
1292 {
1293         struct dlm_query_nodeinfo *qn;
1294         struct dlm_ctxt *dlm = NULL;
1295         int locked = 0, status = -EINVAL;
1296 
1297         qn = (struct dlm_query_nodeinfo *) msg->buf;
1298 
1299         mlog(0, "Node %u queries nodes on domain %s\n", qn->qn_nodenum,
1300              qn->qn_domain);
1301 
1302         spin_lock(&dlm_domain_lock);
1303         dlm = __dlm_lookup_domain_full(qn->qn_domain, qn->qn_namelen);
1304         if (!dlm) {
1305                 mlog(ML_ERROR, "Node %d queried nodes on domain %s before "
1306                      "join domain\n", qn->qn_nodenum, qn->qn_domain);
1307                 goto bail;
1308         }
1309 
1310         spin_lock(&dlm->spinlock);
1311         locked = 1;
1312         if (dlm->joining_node != qn->qn_nodenum) {
1313                 mlog(ML_ERROR, "Node %d queried nodes on domain %s but "
1314                      "joining node is %d\n", qn->qn_nodenum, qn->qn_domain,
1315                      dlm->joining_node);
1316                 goto bail;
1317         }
1318 
1319         /* Support for node query was added in 1.1 */
1320         if (dlm->dlm_locking_proto.pv_major == 1 &&
1321             dlm->dlm_locking_proto.pv_minor == 0) {
1322                 mlog(ML_ERROR, "Node %d queried nodes on domain %s "
1323                      "but active dlm protocol is %d.%d\n", qn->qn_nodenum,
1324                      qn->qn_domain, dlm->dlm_locking_proto.pv_major,
1325                      dlm->dlm_locking_proto.pv_minor);
1326                 goto bail;
1327         }
1328 
1329         status = dlm_match_nodes(dlm, qn);
1330 
1331 bail:
1332         if (locked)
1333                 spin_unlock(&dlm->spinlock);
1334         spin_unlock(&dlm_domain_lock);
1335 
1336         return status;
1337 }
1338 
1339 static int dlm_cancel_join_handler(struct o2net_msg *msg, u32 len, void *data,
1340                                    void **ret_data)
1341 {
1342         struct dlm_cancel_join *cancel;
1343         struct dlm_ctxt *dlm = NULL;
1344 
1345         cancel = (struct dlm_cancel_join *) msg->buf;
1346 
1347         mlog(0, "node %u cancels join on domain %s\n", cancel->node_idx,
1348                   cancel->domain);
1349 
1350         spin_lock(&dlm_domain_lock);
1351         dlm = __dlm_lookup_domain_full(cancel->domain, cancel->name_len);
1352 
1353         if (dlm) {
1354                 spin_lock(&dlm->spinlock);
1355 
1356                 /* Yikes, this guy wants to cancel his join. No
1357                  * problem, we simply cleanup our join state. */
1358                 BUG_ON(dlm->joining_node != cancel->node_idx);
1359                 __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
1360 
1361                 spin_unlock(&dlm->spinlock);
1362         }
1363         spin_unlock(&dlm_domain_lock);
1364 
1365         return 0;
1366 }
1367 
1368 static int dlm_send_one_join_cancel(struct dlm_ctxt *dlm,
1369                                     unsigned int node)
1370 {
1371         int status;
1372         struct dlm_cancel_join cancel_msg;
1373 
1374         memset(&cancel_msg, 0, sizeof(cancel_msg));
1375         cancel_msg.node_idx = dlm->node_num;
1376         cancel_msg.name_len = strlen(dlm->name);
1377         memcpy(cancel_msg.domain, dlm->name, cancel_msg.name_len);
1378 
1379         status = o2net_send_message(DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
1380                                     &cancel_msg, sizeof(cancel_msg), node,
1381                                     NULL);
1382         if (status < 0) {
1383                 mlog(ML_ERROR, "Error %d when sending message %u (key 0x%x) to "
1384                      "node %u\n", status, DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
1385                      node);
1386                 goto bail;
1387         }
1388 
1389 bail:
1390         return status;
1391 }
1392 
1393 /* map_size should be in bytes. */
1394 static int dlm_send_join_cancels(struct dlm_ctxt *dlm,
1395                                  unsigned long *node_map,
1396                                  unsigned int map_size)
1397 {
1398         int status, tmpstat;
1399         unsigned int node;
1400 
1401         if (map_size != (BITS_TO_LONGS(O2NM_MAX_NODES) *
1402                          sizeof(unsigned long))) {
1403                 mlog(ML_ERROR,
1404                      "map_size %u != BITS_TO_LONGS(O2NM_MAX_NODES) %u\n",
1405                      map_size, (unsigned)BITS_TO_LONGS(O2NM_MAX_NODES));
1406                 return -EINVAL;
1407         }
1408 
1409         status = 0;
1410         node = -1;
1411         while ((node = find_next_bit(node_map, O2NM_MAX_NODES,
1412                                      node + 1)) < O2NM_MAX_NODES) {
1413                 if (node == dlm->node_num)
1414                         continue;
1415 
1416                 tmpstat = dlm_send_one_join_cancel(dlm, node);
1417                 if (tmpstat) {
1418                         mlog(ML_ERROR, "Error return %d cancelling join on "
1419                              "node %d\n", tmpstat, node);
1420                         if (!status)
1421                                 status = tmpstat;
1422                 }
1423         }
1424 
1425         if (status)
1426                 mlog_errno(status);
1427         return status;
1428 }
1429 
1430 static int dlm_request_join(struct dlm_ctxt *dlm,
1431                             int node,
1432                             enum dlm_query_join_response_code *response)
1433 {
1434         int status;
1435         struct dlm_query_join_request join_msg;
1436         struct dlm_query_join_packet packet;
1437         u32 join_resp;
1438 
1439         mlog(0, "querying node %d\n", node);
1440 
1441         memset(&join_msg, 0, sizeof(join_msg));
1442         join_msg.node_idx = dlm->node_num;
1443         join_msg.name_len = strlen(dlm->name);
1444         memcpy(join_msg.domain, dlm->name, join_msg.name_len);
1445         join_msg.dlm_proto = dlm->dlm_locking_proto;
1446         join_msg.fs_proto = dlm->fs_locking_proto;
1447 
1448         /* copy live node map to join message */
1449         byte_copymap(join_msg.node_map, dlm->live_nodes_map, O2NM_MAX_NODES);
1450 
1451         status = o2net_send_message(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY, &join_msg,
1452                                     sizeof(join_msg), node, &join_resp);
1453         if (status < 0 && status != -ENOPROTOOPT) {
1454                 mlog(ML_ERROR, "Error %d when sending message %u (key 0x%x) to "
1455                      "node %u\n", status, DLM_QUERY_JOIN_MSG, DLM_MOD_KEY,
1456                      node);
1457                 goto bail;
1458         }
1459         dlm_query_join_wire_to_packet(join_resp, &packet);
1460 
1461         /* -ENOPROTOOPT from the net code means the other side isn't
1462             listening for our message type -- that's fine, it means
1463             his dlm isn't up, so we can consider him a 'yes' but not
1464             joined into the domain.  */
1465         if (status == -ENOPROTOOPT) {
1466                 status = 0;
1467                 *response = JOIN_OK_NO_MAP;
1468         } else {
1469                 *response = packet.code;
1470                 switch (packet.code) {
1471                 case JOIN_DISALLOW:
1472                 case JOIN_OK_NO_MAP:
1473                         break;
1474                 case JOIN_PROTOCOL_MISMATCH:
1475                         mlog(ML_NOTICE,
1476                              "This node requested DLM locking protocol %u.%u and "
1477                              "filesystem locking protocol %u.%u.  At least one of "
1478                              "the protocol versions on node %d is not compatible, "
1479                              "disconnecting\n",
1480                              dlm->dlm_locking_proto.pv_major,
1481                              dlm->dlm_locking_proto.pv_minor,
1482                              dlm->fs_locking_proto.pv_major,
1483                              dlm->fs_locking_proto.pv_minor,
1484                              node);
1485                         status = -EPROTO;
1486                         break;
1487                 case JOIN_OK:
1488                         /* Use the same locking protocol as the remote node */
1489                         dlm->dlm_locking_proto.pv_minor = packet.dlm_minor;
1490                         dlm->fs_locking_proto.pv_minor = packet.fs_minor;
1491                         mlog(0,
1492                              "Node %d responds JOIN_OK with DLM locking protocol "
1493                              "%u.%u and fs locking protocol %u.%u\n",
1494                              node,
1495                              dlm->dlm_locking_proto.pv_major,
1496                              dlm->dlm_locking_proto.pv_minor,
1497                              dlm->fs_locking_proto.pv_major,
1498                              dlm->fs_locking_proto.pv_minor);
1499                         break;
1500                 default:
1501                         status = -EINVAL;
1502                         mlog(ML_ERROR, "invalid response %d from node %u\n",
1503                              packet.code, node);
1504                         /* Reset response to JOIN_DISALLOW */
1505                         *response = JOIN_DISALLOW;
1506                         break;
1507                 }
1508         }
1509 
1510         mlog(0, "status %d, node %d response is %d\n", status, node,
1511              *response);
1512 
1513 bail:
1514         return status;
1515 }
1516 
1517 static int dlm_send_one_join_assert(struct dlm_ctxt *dlm,
1518                                     unsigned int node)
1519 {
1520         int status;
1521         int ret;
1522         struct dlm_assert_joined assert_msg;
1523 
1524         mlog(0, "Sending join assert to node %u\n", node);
1525 
1526         memset(&assert_msg, 0, sizeof(assert_msg));
1527         assert_msg.node_idx = dlm->node_num;
1528         assert_msg.name_len = strlen(dlm->name);
1529         memcpy(assert_msg.domain, dlm->name, assert_msg.name_len);
1530 
1531         status = o2net_send_message(DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
1532                                     &assert_msg, sizeof(assert_msg), node,
1533                                     &ret);
1534         if (status < 0)
1535                 mlog(ML_ERROR, "Error %d when sending message %u (key 0x%x) to "
1536                      "node %u\n", status, DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
1537                      node);
1538         else
1539                 status = ret;
1540 
1541         return status;
1542 }
1543 
1544 static void dlm_send_join_asserts(struct dlm_ctxt *dlm,
1545                                   unsigned long *node_map)
1546 {
1547         int status, node, live;
1548 
1549         status = 0;
1550         node = -1;
1551         while ((node = find_next_bit(node_map, O2NM_MAX_NODES,
1552                                      node + 1)) < O2NM_MAX_NODES) {
1553                 if (node == dlm->node_num)
1554                         continue;
1555 
1556                 do {
1557                         /* It is very important that this message be
1558                          * received so we spin until either the node
1559                          * has died or it gets the message. */
1560                         status = dlm_send_one_join_assert(dlm, node);
1561 
1562                         spin_lock(&dlm->spinlock);
1563                         live = test_bit(node, dlm->live_nodes_map);
1564                         spin_unlock(&dlm->spinlock);
1565 
1566                         if (status) {
1567                                 mlog(ML_ERROR, "Error return %d asserting "
1568                                      "join on node %d\n", status, node);
1569 
1570                                 /* give us some time between errors... */
1571                                 if (live)
1572                                         msleep(DLM_DOMAIN_BACKOFF_MS);
1573                         }
1574                 } while (status && live);
1575         }
1576 }
1577 
1578 struct domain_join_ctxt {
1579         unsigned long live_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1580         unsigned long yes_resp_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1581 };
1582 
1583 static int dlm_should_restart_join(struct dlm_ctxt *dlm,
1584                                    struct domain_join_ctxt *ctxt,
1585                                    enum dlm_query_join_response_code response)
1586 {
1587         int ret;
1588 
1589         if (response == JOIN_DISALLOW) {
1590                 mlog(0, "Latest response of disallow -- should restart\n");
1591                 return 1;
1592         }
1593 
1594         spin_lock(&dlm->spinlock);
1595         /* For now, we restart the process if the node maps have
1596          * changed at all */
1597         ret = memcmp(ctxt->live_map, dlm->live_nodes_map,
1598                      sizeof(dlm->live_nodes_map));
1599         spin_unlock(&dlm->spinlock);
1600 
1601         if (ret)
1602                 mlog(0, "Node maps changed -- should restart\n");
1603 
1604         return ret;
1605 }
1606 
1607 static int dlm_try_to_join_domain(struct dlm_ctxt *dlm)
1608 {
1609         int status = 0, tmpstat, node;
1610         struct domain_join_ctxt *ctxt;
1611         enum dlm_query_join_response_code response = JOIN_DISALLOW;
1612 
1613         mlog(0, "%p", dlm);
1614 
1615         ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL);
1616         if (!ctxt) {
1617                 status = -ENOMEM;
1618                 mlog_errno(status);
1619                 goto bail;
1620         }
1621 
1622         /* group sem locking should work for us here -- we're already
1623          * registered for heartbeat events so filling this should be
1624          * atomic wrt getting those handlers called. */
1625         o2hb_fill_node_map(dlm->live_nodes_map, sizeof(dlm->live_nodes_map));
1626 
1627         spin_lock(&dlm->spinlock);
1628         memcpy(ctxt->live_map, dlm->live_nodes_map, sizeof(ctxt->live_map));
1629 
1630         __dlm_set_joining_node(dlm, dlm->node_num);
1631 
1632         spin_unlock(&dlm->spinlock);
1633 
1634         node = -1;
1635         while ((node = find_next_bit(ctxt->live_map, O2NM_MAX_NODES,
1636                                      node + 1)) < O2NM_MAX_NODES) {
1637                 if (node == dlm->node_num)
1638                         continue;
1639 
1640                 status = dlm_request_join(dlm, node, &response);
1641                 if (status < 0) {
1642                         mlog_errno(status);
1643                         goto bail;
1644                 }
1645 
1646                 /* Ok, either we got a response or the node doesn't have a
1647                  * dlm up. */
1648                 if (response == JOIN_OK)
1649                         set_bit(node, ctxt->yes_resp_map);
1650 
1651                 if (dlm_should_restart_join(dlm, ctxt, response)) {
1652                         status = -EAGAIN;
1653                         goto bail;
1654                 }
1655         }
1656 
1657         mlog(0, "Yay, done querying nodes!\n");
1658 
1659         /* Yay, everyone agree's we can join the domain. My domain is
1660          * comprised of all nodes who were put in the
1661          * yes_resp_map. Copy that into our domain map and send a join
1662          * assert message to clean up everyone elses state. */
1663         spin_lock(&dlm->spinlock);
1664         memcpy(dlm->domain_map, ctxt->yes_resp_map,
1665                sizeof(ctxt->yes_resp_map));
1666         set_bit(dlm->node_num, dlm->domain_map);
1667         spin_unlock(&dlm->spinlock);
1668 
1669         /* Support for global heartbeat and node info was added in 1.1 */
1670         if (dlm->dlm_locking_proto.pv_major > 1 ||
1671             dlm->dlm_locking_proto.pv_minor > 0) {
1672                 status = dlm_send_nodeinfo(dlm, ctxt->yes_resp_map);
1673                 if (status) {
1674                         mlog_errno(status);
1675                         goto bail;
1676                 }
1677                 status = dlm_send_regions(dlm, ctxt->yes_resp_map);
1678                 if (status) {
1679                         mlog_errno(status);
1680                         goto bail;
1681                 }
1682         }
1683 
1684         dlm_send_join_asserts(dlm, ctxt->yes_resp_map);
1685 
1686         /* Joined state *must* be set before the joining node
1687          * information, otherwise the query_join handler may read no
1688          * current joiner but a state of NEW and tell joining nodes
1689          * we're not in the domain. */
1690         spin_lock(&dlm_domain_lock);
1691         dlm->dlm_state = DLM_CTXT_JOINED;
1692         dlm->num_joins++;
1693         spin_unlock(&dlm_domain_lock);
1694 
1695 bail:
1696         spin_lock(&dlm->spinlock);
1697         __dlm_set_joining_node(dlm, DLM_LOCK_RES_OWNER_UNKNOWN);
1698         if (!status) {
1699                 printk(KERN_NOTICE "o2dlm: Joining domain %s ", dlm->name);
1700                 __dlm_print_nodes(dlm);
1701         }
1702         spin_unlock(&dlm->spinlock);
1703 
1704         if (ctxt) {
1705                 /* Do we need to send a cancel message to any nodes? */
1706                 if (status < 0) {
1707                         tmpstat = dlm_send_join_cancels(dlm,
1708                                                         ctxt->yes_resp_map,
1709                                                         sizeof(ctxt->yes_resp_map));
1710                         if (tmpstat < 0)
1711                                 mlog_errno(tmpstat);
1712                 }
1713                 kfree(ctxt);
1714         }
1715 
1716         mlog(0, "returning %d\n", status);
1717         return status;
1718 }
1719 
1720 static void dlm_unregister_domain_handlers(struct dlm_ctxt *dlm)
1721 {
1722         o2hb_unregister_callback(dlm->name, &dlm->dlm_hb_up);
1723         o2hb_unregister_callback(dlm->name, &dlm->dlm_hb_down);
1724         o2net_unregister_handler_list(&dlm->dlm_domain_handlers);
1725 }
1726 
1727 static int dlm_register_domain_handlers(struct dlm_ctxt *dlm)
1728 {
1729         int status;
1730 
1731         mlog(0, "registering handlers.\n");
1732 
1733         o2hb_setup_callback(&dlm->dlm_hb_down, O2HB_NODE_DOWN_CB,
1734                             dlm_hb_node_down_cb, dlm, DLM_HB_NODE_DOWN_PRI);
1735         o2hb_setup_callback(&dlm->dlm_hb_up, O2HB_NODE_UP_CB,
1736                             dlm_hb_node_up_cb, dlm, DLM_HB_NODE_UP_PRI);
1737 
1738         status = o2hb_register_callback(dlm->name, &dlm->dlm_hb_down);
1739         if (status)
1740                 goto bail;
1741 
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 
1857 bail:
1858         if (status)
1859                 dlm_unregister_domain_handlers(dlm);
1860 
1861         return status;
1862 }
1863 
1864 static int dlm_join_domain(struct dlm_ctxt *dlm)
1865 {
1866         int status;
1867         unsigned int backoff;
1868         unsigned int total_backoff = 0;
1869 
1870         BUG_ON(!dlm);
1871 
1872         mlog(0, "Join domain %s\n", dlm->name);
1873 
1874         status = dlm_register_domain_handlers(dlm);
1875         if (status) {
1876                 mlog_errno(status);
1877                 goto bail;
1878         }
1879 
1880         status = dlm_launch_thread(dlm);
1881         if (status < 0) {
1882                 mlog_errno(status);
1883                 goto bail;
1884         }
1885 
1886         status = dlm_launch_recovery_thread(dlm);
1887         if (status < 0) {
1888                 mlog_errno(status);
1889                 goto bail;
1890         }
1891 
1892         status = dlm_debug_init(dlm);
1893         if (status < 0) {
1894                 mlog_errno(status);
1895                 goto bail;
1896         }
1897 
1898         dlm->dlm_worker = create_singlethread_workqueue("dlm_wq");
1899         if (!dlm->dlm_worker) {
1900                 status = -ENOMEM;
1901                 mlog_errno(status);
1902                 goto bail;
1903         }
1904 
1905         do {
1906                 status = dlm_try_to_join_domain(dlm);
1907 
1908                 /* If we're racing another node to the join, then we
1909                  * need to back off temporarily and let them
1910                  * complete. */
1911 #define DLM_JOIN_TIMEOUT_MSECS  90000
1912                 if (status == -EAGAIN) {
1913                         if (signal_pending(current)) {
1914                                 status = -ERESTARTSYS;
1915                                 goto bail;
1916                         }
1917 
1918                         if (total_backoff > DLM_JOIN_TIMEOUT_MSECS) {
1919                                 status = -ERESTARTSYS;
1920                                 mlog(ML_NOTICE, "Timed out joining dlm domain "
1921                                      "%s after %u msecs\n", dlm->name,
1922                                      total_backoff);
1923                                 goto bail;
1924                         }
1925 
1926                         /*
1927                          * <chip> After you!
1928                          * <dale> No, after you!
1929                          * <chip> I insist!
1930                          * <dale> But you first!
1931                          * ...
1932                          */
1933                         backoff = (unsigned int)(jiffies & 0x3);
1934                         backoff *= DLM_DOMAIN_BACKOFF_MS;
1935                         total_backoff += backoff;
1936                         mlog(0, "backoff %d\n", backoff);
1937                         msleep(backoff);
1938                 }
1939         } while (status == -EAGAIN);
1940 
1941         if (status < 0) {
1942                 mlog_errno(status);
1943                 goto bail;
1944         }
1945 
1946         status = 0;
1947 bail:
1948         wake_up(&dlm_domain_events);
1949 
1950         if (status) {
1951                 dlm_unregister_domain_handlers(dlm);
1952                 dlm_debug_shutdown(dlm);
1953                 dlm_complete_thread(dlm);
1954                 dlm_complete_recovery_thread(dlm);
1955                 dlm_destroy_dlm_worker(dlm);
1956         }
1957 
1958         return status;
1959 }
1960 
1961 static struct dlm_ctxt *dlm_alloc_ctxt(const char *domain,
1962                                 u32 key)
1963 {
1964         int i;
1965         int ret;
1966         struct dlm_ctxt *dlm = NULL;
1967 
1968         dlm = kzalloc(sizeof(*dlm), GFP_KERNEL);
1969         if (!dlm) {
1970                 ret = -ENOMEM;
1971                 mlog_errno(ret);
1972                 goto leave;
1973         }
1974 
1975         dlm->name = kstrdup(domain, GFP_KERNEL);
1976         if (dlm->name == NULL) {
1977                 ret = -ENOMEM;
1978                 mlog_errno(ret);
1979                 goto leave;
1980         }
1981 
1982         dlm->lockres_hash = (struct hlist_head **)dlm_alloc_pagevec(DLM_HASH_PAGES);
1983         if (!dlm->lockres_hash) {
1984                 ret = -ENOMEM;
1985                 mlog_errno(ret);
1986                 goto leave;
1987         }
1988 
1989         for (i = 0; i < DLM_HASH_BUCKETS; i++)
1990                 INIT_HLIST_HEAD(dlm_lockres_hash(dlm, i));
1991 
1992         dlm->master_hash = (struct hlist_head **)
1993                                 dlm_alloc_pagevec(DLM_HASH_PAGES);
1994         if (!dlm->master_hash) {
1995                 ret = -ENOMEM;
1996                 mlog_errno(ret);
1997                 goto leave;
1998         }
1999 
2000         for (i = 0; i < DLM_HASH_BUCKETS; i++)
2001                 INIT_HLIST_HEAD(dlm_master_hash(dlm, i));
2002 
2003         dlm->key = key;
2004         dlm->node_num = o2nm_this_node();
2005 
2006         ret = dlm_create_debugfs_subroot(dlm);
2007         if (ret < 0)
2008                 goto leave;
2009 
2010         spin_lock_init(&dlm->spinlock);
2011         spin_lock_init(&dlm->master_lock);
2012         spin_lock_init(&dlm->ast_lock);
2013         spin_lock_init(&dlm->track_lock);
2014         INIT_LIST_HEAD(&dlm->list);
2015         INIT_LIST_HEAD(&dlm->dirty_list);
2016         INIT_LIST_HEAD(&dlm->reco.resources);
2017         INIT_LIST_HEAD(&dlm->reco.node_data);
2018         INIT_LIST_HEAD(&dlm->purge_list);
2019         INIT_LIST_HEAD(&dlm->dlm_domain_handlers);
2020         INIT_LIST_HEAD(&dlm->tracking_list);
2021         dlm->reco.state = 0;
2022 
2023         INIT_LIST_HEAD(&dlm->pending_asts);
2024         INIT_LIST_HEAD(&dlm->pending_basts);
2025 
2026         mlog(0, "dlm->recovery_map=%p, &(dlm->recovery_map[0])=%p\n",
2027                   dlm->recovery_map, &(dlm->recovery_map[0]));
2028 
2029         memset(dlm->recovery_map, 0, sizeof(dlm->recovery_map));
2030         memset(dlm->live_nodes_map, 0, sizeof(dlm->live_nodes_map));
2031         memset(dlm->domain_map, 0, sizeof(dlm->domain_map));
2032 
2033         dlm->dlm_thread_task = NULL;
2034         dlm->dlm_reco_thread_task = NULL;
2035         dlm->dlm_worker = NULL;
2036         init_waitqueue_head(&dlm->dlm_thread_wq);
2037         init_waitqueue_head(&dlm->dlm_reco_thread_wq);
2038         init_waitqueue_head(&dlm->reco.event);
2039         init_waitqueue_head(&dlm->ast_wq);
2040         init_waitqueue_head(&dlm->migration_wq);
2041         INIT_LIST_HEAD(&dlm->mle_hb_events);
2042 
2043         dlm->joining_node = DLM_LOCK_RES_OWNER_UNKNOWN;
2044         init_waitqueue_head(&dlm->dlm_join_events);
2045 
2046         dlm->reco.new_master = O2NM_INVALID_NODE_NUM;
2047         dlm->reco.dead_node = O2NM_INVALID_NODE_NUM;
2048 
2049         atomic_set(&dlm->res_tot_count, 0);
2050         atomic_set(&dlm->res_cur_count, 0);
2051         for (i = 0; i < DLM_MLE_NUM_TYPES; ++i) {
2052                 atomic_set(&dlm->mle_tot_count[i], 0);
2053                 atomic_set(&dlm->mle_cur_count[i], 0);
2054         }
2055 
2056         spin_lock_init(&dlm->work_lock);
2057         INIT_LIST_HEAD(&dlm->work_list);
2058         INIT_WORK(&dlm->dispatched_work, dlm_dispatch_work);
2059 
2060         kref_init(&dlm->dlm_refs);
2061         dlm->dlm_state = DLM_CTXT_NEW;
2062 
2063         INIT_LIST_HEAD(&dlm->dlm_eviction_callbacks);
2064 
2065         mlog(0, "context init: refcount %u\n",
2066                   atomic_read(&dlm->dlm_refs.refcount));
2067 
2068 leave:
2069         if (ret < 0 && dlm) {
2070                 if (dlm->master_hash)
2071                         dlm_free_pagevec((void **)dlm->master_hash,
2072                                         DLM_HASH_PAGES);
2073 
2074                 if (dlm->lockres_hash)
2075                         dlm_free_pagevec((void **)dlm->lockres_hash,
2076                                         DLM_HASH_PAGES);
2077 
2078                 kfree(dlm->name);
2079                 kfree(dlm);
2080                 dlm = NULL;
2081         }
2082         return dlm;
2083 }
2084 
2085 /*
2086  * Compare a requested locking protocol version against the current one.
2087  *
2088  * If the major numbers are different, they are incompatible.
2089  * If the current minor is greater than the request, they are incompatible.
2090  * If the current minor is less than or equal to the request, they are
2091  * compatible, and the requester should run at the current minor version.
2092  */
2093 static int dlm_protocol_compare(struct dlm_protocol_version *existing,
2094                                 struct dlm_protocol_version *request)
2095 {
2096         if (existing->pv_major != request->pv_major)
2097                 return 1;
2098 
2099         if (existing->pv_minor > request->pv_minor)
2100                 return 1;
2101 
2102         if (existing->pv_minor < request->pv_minor)
2103                 request->pv_minor = existing->pv_minor;
2104 
2105         return 0;
2106 }
2107 
2108 /*
2109  * dlm_register_domain: one-time setup per "domain".
2110  *
2111  * The filesystem passes in the requested locking version via proto.
2112  * If registration was successful, proto will contain the negotiated
2113  * locking protocol.
2114  */
2115 struct dlm_ctxt * dlm_register_domain(const char *domain,
2116                                u32 key,
2117                                struct dlm_protocol_version *fs_proto)
2118 {
2119         int ret;
2120         struct dlm_ctxt *dlm = NULL;
2121         struct dlm_ctxt *new_ctxt = NULL;
2122 
2123         if (strlen(domain) >= O2NM_MAX_NAME_LEN) {
2124                 ret = -ENAMETOOLONG;
2125                 mlog(ML_ERROR, "domain name length too long\n");
2126                 goto leave;
2127         }
2128 
2129         mlog(0, "register called for domain \"%s\"\n", domain);
2130 
2131 retry:
2132         dlm = NULL;
2133         if (signal_pending(current)) {
2134                 ret = -ERESTARTSYS;
2135                 mlog_errno(ret);
2136                 goto leave;
2137         }
2138 
2139         spin_lock(&dlm_domain_lock);
2140 
2141         dlm = __dlm_lookup_domain(domain);
2142         if (dlm) {
2143                 if (dlm->dlm_state != DLM_CTXT_JOINED) {
2144                         spin_unlock(&dlm_domain_lock);
2145 
2146                         mlog(0, "This ctxt is not joined yet!\n");
2147                         wait_event_interruptible(dlm_domain_events,
2148                                                  dlm_wait_on_domain_helper(
2149                                                          domain));
2150                         goto retry;
2151                 }
2152 
2153                 if (dlm_protocol_compare(&dlm->fs_locking_proto, fs_proto)) {
2154                         spin_unlock(&dlm_domain_lock);
2155                         mlog(ML_ERROR,
2156                              "Requested locking protocol version is not "
2157                              "compatible with already registered domain "
2158                              "\"%s\"\n", domain);
2159                         ret = -EPROTO;
2160                         goto leave;
2161                 }
2162 
2163                 __dlm_get(dlm);
2164                 dlm->num_joins++;
2165 
2166                 spin_unlock(&dlm_domain_lock);
2167 
2168                 ret = 0;
2169                 goto leave;
2170         }
2171 
2172         /* doesn't exist */
2173         if (!new_ctxt) {
2174                 spin_unlock(&dlm_domain_lock);
2175 
2176                 new_ctxt = dlm_alloc_ctxt(domain, key);
2177                 if (new_ctxt)
2178                         goto retry;
2179 
2180                 ret = -ENOMEM;
2181                 mlog_errno(ret);
2182                 goto leave;
2183         }
2184 
2185         /* a little variable switch-a-roo here... */
2186         dlm = new_ctxt;
2187         new_ctxt = NULL;
2188 
2189         /* add the new domain */
2190         list_add_tail(&dlm->list, &dlm_domains);
2191         spin_unlock(&dlm_domain_lock);
2192 
2193         /*
2194          * Pass the locking protocol version into the join.  If the join
2195          * succeeds, it will have the negotiated protocol set.
2196          */
2197         dlm->dlm_locking_proto = dlm_protocol;
2198         dlm->fs_locking_proto = *fs_proto;
2199 
2200         ret = dlm_join_domain(dlm);
2201         if (ret) {
2202                 mlog_errno(ret);
2203                 dlm_put(dlm);
2204                 goto leave;
2205         }
2206 
2207         /* Tell the caller what locking protocol we negotiated */
2208         *fs_proto = dlm->fs_locking_proto;
2209 
2210         ret = 0;
2211 leave:
2212         if (new_ctxt)
2213                 dlm_free_ctxt_mem(new_ctxt);
2214 
2215         if (ret < 0)
2216                 dlm = ERR_PTR(ret);
2217 
2218         return dlm;
2219 }
2220 EXPORT_SYMBOL_GPL(dlm_register_domain);
2221 
2222 static LIST_HEAD(dlm_join_handlers);
2223 
2224 static void dlm_unregister_net_handlers(void)
2225 {
2226         o2net_unregister_handler_list(&dlm_join_handlers);
2227 }
2228 
2229 static int dlm_register_net_handlers(void)
2230 {
2231         int status = 0;
2232 
2233         status = o2net_register_handler(DLM_QUERY_JOIN_MSG, DLM_MOD_KEY,
2234                                         sizeof(struct dlm_query_join_request),
2235                                         dlm_query_join_handler,
2236                                         NULL, NULL, &dlm_join_handlers);
2237         if (status)
2238                 goto bail;
2239 
2240         status = o2net_register_handler(DLM_ASSERT_JOINED_MSG, DLM_MOD_KEY,
2241                                         sizeof(struct dlm_assert_joined),
2242                                         dlm_assert_joined_handler,
2243                                         NULL, NULL, &dlm_join_handlers);
2244         if (status)
2245                 goto bail;
2246 
2247         status = o2net_register_handler(DLM_CANCEL_JOIN_MSG, DLM_MOD_KEY,
2248                                         sizeof(struct dlm_cancel_join),
2249                                         dlm_cancel_join_handler,
2250                                         NULL, NULL, &dlm_join_handlers);
2251         if (status)
2252                 goto bail;
2253 
2254         status = o2net_register_handler(DLM_QUERY_REGION, DLM_MOD_KEY,
2255                                         sizeof(struct dlm_query_region),
2256                                         dlm_query_region_handler,
2257                                         NULL, NULL, &dlm_join_handlers);
2258 
2259         if (status)
2260                 goto bail;
2261 
2262         status = o2net_register_handler(DLM_QUERY_NODEINFO, DLM_MOD_KEY,
2263                                         sizeof(struct dlm_query_nodeinfo),
2264                                         dlm_query_nodeinfo_handler,
2265                                         NULL, NULL, &dlm_join_handlers);
2266 bail:
2267         if (status < 0)
2268                 dlm_unregister_net_handlers();
2269 
2270         return status;
2271 }
2272 
2273 /* Domain eviction callback handling.
2274  *
2275  * The file system requires notification of node death *before* the
2276  * dlm completes it's recovery work, otherwise it may be able to
2277  * acquire locks on resources requiring recovery. Since the dlm can
2278  * evict a node from it's domain *before* heartbeat fires, a similar
2279  * mechanism is required. */
2280 
2281 /* Eviction is not expected to happen often, so a per-domain lock is
2282  * not necessary. Eviction callbacks are allowed to sleep for short
2283  * periods of time. */
2284 static DECLARE_RWSEM(dlm_callback_sem);
2285 
2286 void dlm_fire_domain_eviction_callbacks(struct dlm_ctxt *dlm,
2287                                         int node_num)
2288 {
2289         struct dlm_eviction_cb *cb;
2290 
2291         down_read(&dlm_callback_sem);
2292         list_for_each_entry(cb, &dlm->dlm_eviction_callbacks, ec_item) {
2293                 cb->ec_func(node_num, cb->ec_data);
2294         }
2295         up_read(&dlm_callback_sem);
2296 }
2297 
2298 void dlm_setup_eviction_cb(struct dlm_eviction_cb *cb,
2299                            dlm_eviction_func *f,
2300                            void *data)
2301 {
2302         INIT_LIST_HEAD(&cb->ec_item);
2303         cb->ec_func = f;
2304         cb->ec_data = data;
2305 }
2306 EXPORT_SYMBOL_GPL(dlm_setup_eviction_cb);
2307 
2308 void dlm_register_eviction_cb(struct dlm_ctxt *dlm,
2309                               struct dlm_eviction_cb *cb)
2310 {
2311         down_write(&dlm_callback_sem);
2312         list_add_tail(&cb->ec_item, &dlm->dlm_eviction_callbacks);
2313         up_write(&dlm_callback_sem);
2314 }
2315 EXPORT_SYMBOL_GPL(dlm_register_eviction_cb);
2316 
2317 void dlm_unregister_eviction_cb(struct dlm_eviction_cb *cb)
2318 {
2319         down_write(&dlm_callback_sem);
2320         list_del_init(&cb->ec_item);
2321         up_write(&dlm_callback_sem);
2322 }
2323 EXPORT_SYMBOL_GPL(dlm_unregister_eviction_cb);
2324 
2325 static int __init dlm_init(void)
2326 {
2327         int status;
2328 
2329         status = dlm_init_mle_cache();
2330         if (status) {
2331                 mlog(ML_ERROR, "Could not create o2dlm_mle slabcache\n");
2332                 goto error;
2333         }
2334 
2335         status = dlm_init_master_caches();
2336         if (status) {
2337                 mlog(ML_ERROR, "Could not create o2dlm_lockres and "
2338                      "o2dlm_lockname slabcaches\n");
2339                 goto error;
2340         }
2341 
2342         status = dlm_init_lock_cache();
2343         if (status) {
2344                 mlog(ML_ERROR, "Count not create o2dlm_lock slabcache\n");
2345                 goto error;
2346         }
2347 
2348         status = dlm_register_net_handlers();
2349         if (status) {
2350                 mlog(ML_ERROR, "Unable to register network handlers\n");
2351                 goto error;
2352         }
2353 
2354         status = dlm_create_debugfs_root();
2355         if (status)
2356                 goto error;
2357 
2358         return 0;
2359 error:
2360         dlm_unregister_net_handlers();
2361         dlm_destroy_lock_cache();
2362         dlm_destroy_master_caches();
2363         dlm_destroy_mle_cache();
2364         return -1;
2365 }
2366 
2367 static void __exit dlm_exit (void)
2368 {
2369         dlm_destroy_debugfs_root();
2370         dlm_unregister_net_handlers();
2371         dlm_destroy_lock_cache();
2372         dlm_destroy_master_caches();
2373         dlm_destroy_mle_cache();
2374 }
2375 
2376 MODULE_AUTHOR("Oracle");
2377 MODULE_LICENSE("GPL");
2378 MODULE_DESCRIPTION("OCFS2 Distributed Lock Management");
2379 
2380 module_init(dlm_init);
2381 module_exit(dlm_exit);
2382 

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