1 /* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
3 *
4 * dlmmod.c
5 *
6 * standalone DLM module
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
28 #include <linux/module.h>
29 #include <linux/fs.h>
30 #include <linux/types.h>
31 #include <linux/slab.h>
32 #include <linux/highmem.h>
33 #include <linux/init.h>
34 #include <linux/sysctl.h>
35 #include <linux/random.h>
36 #include <linux/blkdev.h>
37 #include <linux/socket.h>
38 #include <linux/inet.h>
39 #include <linux/spinlock.h>
40 #include <linux/delay.h>
41
42
43 #include "cluster/heartbeat.h"
44 #include "cluster/nodemanager.h"
45 #include "cluster/tcp.h"
46
47 #include "dlmapi.h"
48 #include "dlmcommon.h"
49 #include "dlmdomain.h"
50 #include "dlmdebug.h"
51
52 #define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_MASTER)
53 #include "cluster/masklog.h"
54
55 static void dlm_mle_node_down(struct dlm_ctxt *dlm,
56 struct dlm_master_list_entry *mle,
57 struct o2nm_node *node,
58 int idx);
59 static void dlm_mle_node_up(struct dlm_ctxt *dlm,
60 struct dlm_master_list_entry *mle,
61 struct o2nm_node *node,
62 int idx);
63
64 static void dlm_assert_master_worker(struct dlm_work_item *item, void *data);
65 static int dlm_do_assert_master(struct dlm_ctxt *dlm,
66 struct dlm_lock_resource *res,
67 void *nodemap, u32 flags);
68 static void dlm_deref_lockres_worker(struct dlm_work_item *item, void *data);
69
70 static inline int dlm_mle_equal(struct dlm_ctxt *dlm,
71 struct dlm_master_list_entry *mle,
72 const char *name,
73 unsigned int namelen)
74 {
75 if (dlm != mle->dlm)
76 return 0;
77
78 if (namelen != mle->mnamelen ||
79 memcmp(name, mle->mname, namelen) != 0)
80 return 0;
81
82 return 1;
83 }
84
85 static struct kmem_cache *dlm_lockres_cache = NULL;
86 static struct kmem_cache *dlm_lockname_cache = NULL;
87 static struct kmem_cache *dlm_mle_cache = NULL;
88
89 static void dlm_mle_release(struct kref *kref);
90 static void dlm_init_mle(struct dlm_master_list_entry *mle,
91 enum dlm_mle_type type,
92 struct dlm_ctxt *dlm,
93 struct dlm_lock_resource *res,
94 const char *name,
95 unsigned int namelen);
96 static void dlm_put_mle(struct dlm_master_list_entry *mle);
97 static void __dlm_put_mle(struct dlm_master_list_entry *mle);
98 static int dlm_find_mle(struct dlm_ctxt *dlm,
99 struct dlm_master_list_entry **mle,
100 char *name, unsigned int namelen);
101
102 static int dlm_do_master_request(struct dlm_lock_resource *res,
103 struct dlm_master_list_entry *mle, int to);
104
105
106 static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
107 struct dlm_lock_resource *res,
108 struct dlm_master_list_entry *mle,
109 int *blocked);
110 static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
111 struct dlm_lock_resource *res,
112 struct dlm_master_list_entry *mle,
113 int blocked);
114 static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
115 struct dlm_lock_resource *res,
116 struct dlm_master_list_entry *mle,
117 struct dlm_master_list_entry **oldmle,
118 const char *name, unsigned int namelen,
119 u8 new_master, u8 master);
120
121 static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
122 struct dlm_lock_resource *res);
123 static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
124 struct dlm_lock_resource *res);
125 static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
126 struct dlm_lock_resource *res,
127 u8 target);
128 static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
129 struct dlm_lock_resource *res);
130
131
132 int dlm_is_host_down(int errno)
133 {
134 switch (errno) {
135 case -EBADF:
136 case -ECONNREFUSED:
137 case -ENOTCONN:
138 case -ECONNRESET:
139 case -EPIPE:
140 case -EHOSTDOWN:
141 case -EHOSTUNREACH:
142 case -ETIMEDOUT:
143 case -ECONNABORTED:
144 case -ENETDOWN:
145 case -ENETUNREACH:
146 case -ENETRESET:
147 case -ESHUTDOWN:
148 case -ENOPROTOOPT:
149 case -EINVAL: /* if returned from our tcp code,
150 this means there is no socket */
151 return 1;
152 }
153 return 0;
154 }
155
156
157 /*
158 * MASTER LIST FUNCTIONS
159 */
160
161
162 /*
163 * regarding master list entries and heartbeat callbacks:
164 *
165 * in order to avoid sleeping and allocation that occurs in
166 * heartbeat, master list entries are simply attached to the
167 * dlm's established heartbeat callbacks. the mle is attached
168 * when it is created, and since the dlm->spinlock is held at
169 * that time, any heartbeat event will be properly discovered
170 * by the mle. the mle needs to be detached from the
171 * dlm->mle_hb_events list as soon as heartbeat events are no
172 * longer useful to the mle, and before the mle is freed.
173 *
174 * as a general rule, heartbeat events are no longer needed by
175 * the mle once an "answer" regarding the lock master has been
176 * received.
177 */
178 static inline void __dlm_mle_attach_hb_events(struct dlm_ctxt *dlm,
179 struct dlm_master_list_entry *mle)
180 {
181 assert_spin_locked(&dlm->spinlock);
182
183 list_add_tail(&mle->hb_events, &dlm->mle_hb_events);
184 }
185
186
187 static inline void __dlm_mle_detach_hb_events(struct dlm_ctxt *dlm,
188 struct dlm_master_list_entry *mle)
189 {
190 if (!list_empty(&mle->hb_events))
191 list_del_init(&mle->hb_events);
192 }
193
194
195 static inline void dlm_mle_detach_hb_events(struct dlm_ctxt *dlm,
196 struct dlm_master_list_entry *mle)
197 {
198 spin_lock(&dlm->spinlock);
199 __dlm_mle_detach_hb_events(dlm, mle);
200 spin_unlock(&dlm->spinlock);
201 }
202
203 static void dlm_get_mle_inuse(struct dlm_master_list_entry *mle)
204 {
205 struct dlm_ctxt *dlm;
206 dlm = mle->dlm;
207
208 assert_spin_locked(&dlm->spinlock);
209 assert_spin_locked(&dlm->master_lock);
210 mle->inuse++;
211 kref_get(&mle->mle_refs);
212 }
213
214 static void dlm_put_mle_inuse(struct dlm_master_list_entry *mle)
215 {
216 struct dlm_ctxt *dlm;
217 dlm = mle->dlm;
218
219 spin_lock(&dlm->spinlock);
220 spin_lock(&dlm->master_lock);
221 mle->inuse--;
222 __dlm_put_mle(mle);
223 spin_unlock(&dlm->master_lock);
224 spin_unlock(&dlm->spinlock);
225
226 }
227
228 /* remove from list and free */
229 static void __dlm_put_mle(struct dlm_master_list_entry *mle)
230 {
231 struct dlm_ctxt *dlm;
232 dlm = mle->dlm;
233
234 assert_spin_locked(&dlm->spinlock);
235 assert_spin_locked(&dlm->master_lock);
236 if (!atomic_read(&mle->mle_refs.refcount)) {
237 /* this may or may not crash, but who cares.
238 * it's a BUG. */
239 mlog(ML_ERROR, "bad mle: %p\n", mle);
240 dlm_print_one_mle(mle);
241 BUG();
242 } else
243 kref_put(&mle->mle_refs, dlm_mle_release);
244 }
245
246
247 /* must not have any spinlocks coming in */
248 static void dlm_put_mle(struct dlm_master_list_entry *mle)
249 {
250 struct dlm_ctxt *dlm;
251 dlm = mle->dlm;
252
253 spin_lock(&dlm->spinlock);
254 spin_lock(&dlm->master_lock);
255 __dlm_put_mle(mle);
256 spin_unlock(&dlm->master_lock);
257 spin_unlock(&dlm->spinlock);
258 }
259
260 static inline void dlm_get_mle(struct dlm_master_list_entry *mle)
261 {
262 kref_get(&mle->mle_refs);
263 }
264
265 static void dlm_init_mle(struct dlm_master_list_entry *mle,
266 enum dlm_mle_type type,
267 struct dlm_ctxt *dlm,
268 struct dlm_lock_resource *res,
269 const char *name,
270 unsigned int namelen)
271 {
272 assert_spin_locked(&dlm->spinlock);
273
274 mle->dlm = dlm;
275 mle->type = type;
276 INIT_HLIST_NODE(&mle->master_hash_node);
277 INIT_LIST_HEAD(&mle->hb_events);
278 memset(mle->maybe_map, 0, sizeof(mle->maybe_map));
279 spin_lock_init(&mle->spinlock);
280 init_waitqueue_head(&mle->wq);
281 atomic_set(&mle->woken, 0);
282 kref_init(&mle->mle_refs);
283 memset(mle->response_map, 0, sizeof(mle->response_map));
284 mle->master = O2NM_MAX_NODES;
285 mle->new_master = O2NM_MAX_NODES;
286 mle->inuse = 0;
287
288 BUG_ON(mle->type != DLM_MLE_BLOCK &&
289 mle->type != DLM_MLE_MASTER &&
290 mle->type != DLM_MLE_MIGRATION);
291
292 if (mle->type == DLM_MLE_MASTER) {
293 BUG_ON(!res);
294 mle->mleres = res;
295 memcpy(mle->mname, res->lockname.name, res->lockname.len);
296 mle->mnamelen = res->lockname.len;
297 mle->mnamehash = res->lockname.hash;
298 } else {
299 BUG_ON(!name);
300 mle->mleres = NULL;
301 memcpy(mle->mname, name, namelen);
302 mle->mnamelen = namelen;
303 mle->mnamehash = dlm_lockid_hash(name, namelen);
304 }
305
306 atomic_inc(&dlm->mle_tot_count[mle->type]);
307 atomic_inc(&dlm->mle_cur_count[mle->type]);
308
309 /* copy off the node_map and register hb callbacks on our copy */
310 memcpy(mle->node_map, dlm->domain_map, sizeof(mle->node_map));
311 memcpy(mle->vote_map, dlm->domain_map, sizeof(mle->vote_map));
312 clear_bit(dlm->node_num, mle->vote_map);
313 clear_bit(dlm->node_num, mle->node_map);
314
315 /* attach the mle to the domain node up/down events */
316 __dlm_mle_attach_hb_events(dlm, mle);
317 }
318
319 void __dlm_unlink_mle(struct dlm_ctxt *dlm, struct dlm_master_list_entry *mle)
320 {
321 assert_spin_locked(&dlm->spinlock);
322 assert_spin_locked(&dlm->master_lock);
323
324 if (!hlist_unhashed(&mle->master_hash_node))
325 hlist_del_init(&mle->master_hash_node);
326 }
327
328 void __dlm_insert_mle(struct dlm_ctxt *dlm, struct dlm_master_list_entry *mle)
329 {
330 struct hlist_head *bucket;
331
332 assert_spin_locked(&dlm->master_lock);
333
334 bucket = dlm_master_hash(dlm, mle->mnamehash);
335 hlist_add_head(&mle->master_hash_node, bucket);
336 }
337
338 /* returns 1 if found, 0 if not */
339 static int dlm_find_mle(struct dlm_ctxt *dlm,
340 struct dlm_master_list_entry **mle,
341 char *name, unsigned int namelen)
342 {
343 struct dlm_master_list_entry *tmpmle;
344 struct hlist_head *bucket;
345 struct hlist_node *list;
346 unsigned int hash;
347
348 assert_spin_locked(&dlm->master_lock);
349
350 hash = dlm_lockid_hash(name, namelen);
351 bucket = dlm_master_hash(dlm, hash);
352 hlist_for_each(list, bucket) {
353 tmpmle = hlist_entry(list, struct dlm_master_list_entry,
354 master_hash_node);
355 if (!dlm_mle_equal(dlm, tmpmle, name, namelen))
356 continue;
357 dlm_get_mle(tmpmle);
358 *mle = tmpmle;
359 return 1;
360 }
361 return 0;
362 }
363
364 void dlm_hb_event_notify_attached(struct dlm_ctxt *dlm, int idx, int node_up)
365 {
366 struct dlm_master_list_entry *mle;
367
368 assert_spin_locked(&dlm->spinlock);
369
370 list_for_each_entry(mle, &dlm->mle_hb_events, hb_events) {
371 if (node_up)
372 dlm_mle_node_up(dlm, mle, NULL, idx);
373 else
374 dlm_mle_node_down(dlm, mle, NULL, idx);
375 }
376 }
377
378 static void dlm_mle_node_down(struct dlm_ctxt *dlm,
379 struct dlm_master_list_entry *mle,
380 struct o2nm_node *node, int idx)
381 {
382 spin_lock(&mle->spinlock);
383
384 if (!test_bit(idx, mle->node_map))
385 mlog(0, "node %u already removed from nodemap!\n", idx);
386 else
387 clear_bit(idx, mle->node_map);
388
389 spin_unlock(&mle->spinlock);
390 }
391
392 static void dlm_mle_node_up(struct dlm_ctxt *dlm,
393 struct dlm_master_list_entry *mle,
394 struct o2nm_node *node, int idx)
395 {
396 spin_lock(&mle->spinlock);
397
398 if (test_bit(idx, mle->node_map))
399 mlog(0, "node %u already in node map!\n", idx);
400 else
401 set_bit(idx, mle->node_map);
402
403 spin_unlock(&mle->spinlock);
404 }
405
406
407 int dlm_init_mle_cache(void)
408 {
409 dlm_mle_cache = kmem_cache_create("o2dlm_mle",
410 sizeof(struct dlm_master_list_entry),
411 0, SLAB_HWCACHE_ALIGN,
412 NULL);
413 if (dlm_mle_cache == NULL)
414 return -ENOMEM;
415 return 0;
416 }
417
418 void dlm_destroy_mle_cache(void)
419 {
420 if (dlm_mle_cache)
421 kmem_cache_destroy(dlm_mle_cache);
422 }
423
424 static void dlm_mle_release(struct kref *kref)
425 {
426 struct dlm_master_list_entry *mle;
427 struct dlm_ctxt *dlm;
428
429 mle = container_of(kref, struct dlm_master_list_entry, mle_refs);
430 dlm = mle->dlm;
431
432 assert_spin_locked(&dlm->spinlock);
433 assert_spin_locked(&dlm->master_lock);
434
435 mlog(0, "Releasing mle for %.*s, type %d\n", mle->mnamelen, mle->mname,
436 mle->type);
437
438 /* remove from list if not already */
439 __dlm_unlink_mle(dlm, mle);
440
441 /* detach the mle from the domain node up/down events */
442 __dlm_mle_detach_hb_events(dlm, mle);
443
444 atomic_dec(&dlm->mle_cur_count[mle->type]);
445
446 /* NOTE: kfree under spinlock here.
447 * if this is bad, we can move this to a freelist. */
448 kmem_cache_free(dlm_mle_cache, mle);
449 }
450
451
452 /*
453 * LOCK RESOURCE FUNCTIONS
454 */
455
456 int dlm_init_master_caches(void)
457 {
458 dlm_lockres_cache = kmem_cache_create("o2dlm_lockres",
459 sizeof(struct dlm_lock_resource),
460 0, SLAB_HWCACHE_ALIGN, NULL);
461 if (!dlm_lockres_cache)
462 goto bail;
463
464 dlm_lockname_cache = kmem_cache_create("o2dlm_lockname",
465 DLM_LOCKID_NAME_MAX, 0,
466 SLAB_HWCACHE_ALIGN, NULL);
467 if (!dlm_lockname_cache)
468 goto bail;
469
470 return 0;
471 bail:
472 dlm_destroy_master_caches();
473 return -ENOMEM;
474 }
475
476 void dlm_destroy_master_caches(void)
477 {
478 if (dlm_lockname_cache)
479 kmem_cache_destroy(dlm_lockname_cache);
480
481 if (dlm_lockres_cache)
482 kmem_cache_destroy(dlm_lockres_cache);
483 }
484
485 static void dlm_lockres_release(struct kref *kref)
486 {
487 struct dlm_lock_resource *res;
488 struct dlm_ctxt *dlm;
489
490 res = container_of(kref, struct dlm_lock_resource, refs);
491 dlm = res->dlm;
492
493 /* This should not happen -- all lockres' have a name
494 * associated with them at init time. */
495 BUG_ON(!res->lockname.name);
496
497 mlog(0, "destroying lockres %.*s\n", res->lockname.len,
498 res->lockname.name);
499
500 spin_lock(&dlm->track_lock);
501 if (!list_empty(&res->tracking))
502 list_del_init(&res->tracking);
503 else {
504 mlog(ML_ERROR, "Resource %.*s not on the Tracking list\n",
505 res->lockname.len, res->lockname.name);
506 dlm_print_one_lock_resource(res);
507 }
508 spin_unlock(&dlm->track_lock);
509
510 atomic_dec(&dlm->res_cur_count);
511
512 if (!hlist_unhashed(&res->hash_node) ||
513 !list_empty(&res->granted) ||
514 !list_empty(&res->converting) ||
515 !list_empty(&res->blocked) ||
516 !list_empty(&res->dirty) ||
517 !list_empty(&res->recovering) ||
518 !list_empty(&res->purge)) {
519 mlog(ML_ERROR,
520 "Going to BUG for resource %.*s."
521 " We're on a list! [%c%c%c%c%c%c%c]\n",
522 res->lockname.len, res->lockname.name,
523 !hlist_unhashed(&res->hash_node) ? 'H' : ' ',
524 !list_empty(&res->granted) ? 'G' : ' ',
525 !list_empty(&res->converting) ? 'C' : ' ',
526 !list_empty(&res->blocked) ? 'B' : ' ',
527 !list_empty(&res->dirty) ? 'D' : ' ',
528 !list_empty(&res->recovering) ? 'R' : ' ',
529 !list_empty(&res->purge) ? 'P' : ' ');
530
531 dlm_print_one_lock_resource(res);
532 }
533
534 /* By the time we're ready to blow this guy away, we shouldn't
535 * be on any lists. */
536 BUG_ON(!hlist_unhashed(&res->hash_node));
537 BUG_ON(!list_empty(&res->granted));
538 BUG_ON(!list_empty(&res->converting));
539 BUG_ON(!list_empty(&res->blocked));
540 BUG_ON(!list_empty(&res->dirty));
541 BUG_ON(!list_empty(&res->recovering));
542 BUG_ON(!list_empty(&res->purge));
543
544 kmem_cache_free(dlm_lockname_cache, (void *)res->lockname.name);
545
546 kmem_cache_free(dlm_lockres_cache, res);
547 }
548
549 void dlm_lockres_put(struct dlm_lock_resource *res)
550 {
551 kref_put(&res->refs, dlm_lockres_release);
552 }
553
554 static void dlm_init_lockres(struct dlm_ctxt *dlm,
555 struct dlm_lock_resource *res,
556 const char *name, unsigned int namelen)
557 {
558 char *qname;
559
560 /* If we memset here, we lose our reference to the kmalloc'd
561 * res->lockname.name, so be sure to init every field
562 * correctly! */
563
564 qname = (char *) res->lockname.name;
565 memcpy(qname, name, namelen);
566
567 res->lockname.len = namelen;
568 res->lockname.hash = dlm_lockid_hash(name, namelen);
569
570 init_waitqueue_head(&res->wq);
571 spin_lock_init(&res->spinlock);
572 INIT_HLIST_NODE(&res->hash_node);
573 INIT_LIST_HEAD(&res->granted);
574 INIT_LIST_HEAD(&res->converting);
575 INIT_LIST_HEAD(&res->blocked);
576 INIT_LIST_HEAD(&res->dirty);
577 INIT_LIST_HEAD(&res->recovering);
578 INIT_LIST_HEAD(&res->purge);
579 INIT_LIST_HEAD(&res->tracking);
580 atomic_set(&res->asts_reserved, 0);
581 res->migration_pending = 0;
582 res->inflight_locks = 0;
583
584 res->dlm = dlm;
585
586 kref_init(&res->refs);
587
588 atomic_inc(&dlm->res_tot_count);
589 atomic_inc(&dlm->res_cur_count);
590
591 /* just for consistency */
592 spin_lock(&res->spinlock);
593 dlm_set_lockres_owner(dlm, res, DLM_LOCK_RES_OWNER_UNKNOWN);
594 spin_unlock(&res->spinlock);
595
596 res->state = DLM_LOCK_RES_IN_PROGRESS;
597
598 res->last_used = 0;
599
600 spin_lock(&dlm->spinlock);
601 list_add_tail(&res->tracking, &dlm->tracking_list);
602 spin_unlock(&dlm->spinlock);
603
604 memset(res->lvb, 0, DLM_LVB_LEN);
605 memset(res->refmap, 0, sizeof(res->refmap));
606 }
607
608 struct dlm_lock_resource *dlm_new_lockres(struct dlm_ctxt *dlm,
609 const char *name,
610 unsigned int namelen)
611 {
612 struct dlm_lock_resource *res = NULL;
613
614 res = kmem_cache_zalloc(dlm_lockres_cache, GFP_NOFS);
615 if (!res)
616 goto error;
617
618 res->lockname.name = kmem_cache_zalloc(dlm_lockname_cache, GFP_NOFS);
619 if (!res->lockname.name)
620 goto error;
621
622 dlm_init_lockres(dlm, res, name, namelen);
623 return res;
624
625 error:
626 if (res && res->lockname.name)
627 kmem_cache_free(dlm_lockname_cache, (void *)res->lockname.name);
628
629 if (res)
630 kmem_cache_free(dlm_lockres_cache, res);
631 return NULL;
632 }
633
634 void dlm_lockres_set_refmap_bit(struct dlm_ctxt *dlm,
635 struct dlm_lock_resource *res, int bit)
636 {
637 assert_spin_locked(&res->spinlock);
638
639 mlog(0, "res %.*s, set node %u, %ps()\n", res->lockname.len,
640 res->lockname.name, bit, __builtin_return_address(0));
641
642 set_bit(bit, res->refmap);
643 }
644
645 void dlm_lockres_clear_refmap_bit(struct dlm_ctxt *dlm,
646 struct dlm_lock_resource *res, int bit)
647 {
648 assert_spin_locked(&res->spinlock);
649
650 mlog(0, "res %.*s, clr node %u, %ps()\n", res->lockname.len,
651 res->lockname.name, bit, __builtin_return_address(0));
652
653 clear_bit(bit, res->refmap);
654 }
655
656 static void __dlm_lockres_grab_inflight_ref(struct dlm_ctxt *dlm,
657 struct dlm_lock_resource *res)
658 {
659 res->inflight_locks++;
660
661 mlog(0, "%s: res %.*s, inflight++: now %u, %ps()\n", dlm->name,
662 res->lockname.len, res->lockname.name, res->inflight_locks,
663 __builtin_return_address(0));
664 }
665
666 void dlm_lockres_grab_inflight_ref(struct dlm_ctxt *dlm,
667 struct dlm_lock_resource *res)
668 {
669 assert_spin_locked(&res->spinlock);
670 __dlm_lockres_grab_inflight_ref(dlm, res);
671 }
672
673 void dlm_lockres_drop_inflight_ref(struct dlm_ctxt *dlm,
674 struct dlm_lock_resource *res)
675 {
676 assert_spin_locked(&res->spinlock);
677
678 BUG_ON(res->inflight_locks == 0);
679
680 res->inflight_locks--;
681
682 mlog(0, "%s: res %.*s, inflight--: now %u, %ps()\n", dlm->name,
683 res->lockname.len, res->lockname.name, res->inflight_locks,
684 __builtin_return_address(0));
685
686 wake_up(&res->wq);
687 }
688
689 /*
690 * lookup a lock resource by name.
691 * may already exist in the hashtable.
692 * lockid is null terminated
693 *
694 * if not, allocate enough for the lockres and for
695 * the temporary structure used in doing the mastering.
696 *
697 * also, do a lookup in the dlm->master_list to see
698 * if another node has begun mastering the same lock.
699 * if so, there should be a block entry in there
700 * for this name, and we should *not* attempt to master
701 * the lock here. need to wait around for that node
702 * to assert_master (or die).
703 *
704 */
705 struct dlm_lock_resource * dlm_get_lock_resource(struct dlm_ctxt *dlm,
706 const char *lockid,
707 int namelen,
708 int flags)
709 {
710 struct dlm_lock_resource *tmpres=NULL, *res=NULL;
711 struct dlm_master_list_entry *mle = NULL;
712 struct dlm_master_list_entry *alloc_mle = NULL;
713 int blocked = 0;
714 int ret, nodenum;
715 struct dlm_node_iter iter;
716 unsigned int hash;
717 int tries = 0;
718 int bit, wait_on_recovery = 0;
719
720 BUG_ON(!lockid);
721
722 hash = dlm_lockid_hash(lockid, namelen);
723
724 mlog(0, "get lockres %s (len %d)\n", lockid, namelen);
725
726 lookup:
727 spin_lock(&dlm->spinlock);
728 tmpres = __dlm_lookup_lockres_full(dlm, lockid, namelen, hash);
729 if (tmpres) {
730 spin_unlock(&dlm->spinlock);
731 spin_lock(&tmpres->spinlock);
732
733 /*
734 * Right after dlm spinlock was released, dlm_thread could have
735 * purged the lockres. Check if lockres got unhashed. If so
736 * start over.
737 */
738 if (hlist_unhashed(&tmpres->hash_node)) {
739 spin_unlock(&tmpres->spinlock);
740 dlm_lockres_put(tmpres);
741 tmpres = NULL;
742 goto lookup;
743 }
744
745 /* Wait on the thread that is mastering the resource */
746 if (tmpres->owner == DLM_LOCK_RES_OWNER_UNKNOWN) {
747 __dlm_wait_on_lockres(tmpres);
748 BUG_ON(tmpres->owner == DLM_LOCK_RES_OWNER_UNKNOWN);
749 spin_unlock(&tmpres->spinlock);
750 dlm_lockres_put(tmpres);
751 tmpres = NULL;
752 goto lookup;
753 }
754
755 /* Wait on the resource purge to complete before continuing */
756 if (tmpres->state & DLM_LOCK_RES_DROPPING_REF) {
757 BUG_ON(tmpres->owner == dlm->node_num);
758 __dlm_wait_on_lockres_flags(tmpres,
759 DLM_LOCK_RES_DROPPING_REF);
760 spin_unlock(&tmpres->spinlock);
761 dlm_lockres_put(tmpres);
762 tmpres = NULL;
763 goto lookup;
764 }
765
766 /* Grab inflight ref to pin the resource */
767 dlm_lockres_grab_inflight_ref(dlm, tmpres);
768
769 spin_unlock(&tmpres->spinlock);
770 if (res)
771 dlm_lockres_put(res);
772 res = tmpres;
773 goto leave;
774 }
775
776 if (!res) {
777 spin_unlock(&dlm->spinlock);
778 mlog(0, "allocating a new resource\n");
779 /* nothing found and we need to allocate one. */
780 alloc_mle = kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
781 if (!alloc_mle)
782 goto leave;
783 res = dlm_new_lockres(dlm, lockid, namelen);
784 if (!res)
785 goto leave;
786 goto lookup;
787 }
788
789 mlog(0, "no lockres found, allocated our own: %p\n", res);
790
791 if (flags & LKM_LOCAL) {
792 /* caller knows it's safe to assume it's not mastered elsewhere
793 * DONE! return right away */
794 spin_lock(&res->spinlock);
795 dlm_change_lockres_owner(dlm, res, dlm->node_num);
796 __dlm_insert_lockres(dlm, res);
797 dlm_lockres_grab_inflight_ref(dlm, res);
798 spin_unlock(&res->spinlock);
799 spin_unlock(&dlm->spinlock);
800 /* lockres still marked IN_PROGRESS */
801 goto wake_waiters;
802 }
803
804 /* check master list to see if another node has started mastering it */
805 spin_lock(&dlm->master_lock);
806
807 /* if we found a block, wait for lock to be mastered by another node */
808 blocked = dlm_find_mle(dlm, &mle, (char *)lockid, namelen);
809 if (blocked) {
810 int mig;
811 if (mle->type == DLM_MLE_MASTER) {
812 mlog(ML_ERROR, "master entry for nonexistent lock!\n");
813 BUG();
814 }
815 mig = (mle->type == DLM_MLE_MIGRATION);
816 /* if there is a migration in progress, let the migration
817 * finish before continuing. we can wait for the absence
818 * of the MIGRATION mle: either the migrate finished or
819 * one of the nodes died and the mle was cleaned up.
820 * if there is a BLOCK here, but it already has a master
821 * set, we are too late. the master does not have a ref
822 * for us in the refmap. detach the mle and drop it.
823 * either way, go back to the top and start over. */
824 if (mig || mle->master != O2NM_MAX_NODES) {
825 BUG_ON(mig && mle->master == dlm->node_num);
826 /* we arrived too late. the master does not
827 * have a ref for us. retry. */
828 mlog(0, "%s:%.*s: late on %s\n",
829 dlm->name, namelen, lockid,
830 mig ? "MIGRATION" : "BLOCK");
831 spin_unlock(&dlm->master_lock);
832 spin_unlock(&dlm->spinlock);
833
834 /* master is known, detach */
835 if (!mig)
836 dlm_mle_detach_hb_events(dlm, mle);
837 dlm_put_mle(mle);
838 mle = NULL;
839 /* this is lame, but we can't wait on either
840 * the mle or lockres waitqueue here */
841 if (mig)
842 msleep(100);
843 goto lookup;
844 }
845 } else {
846 /* go ahead and try to master lock on this node */
847 mle = alloc_mle;
848 /* make sure this does not get freed below */
849 alloc_mle = NULL;
850 dlm_init_mle(mle, DLM_MLE_MASTER, dlm, res, NULL, 0);
851 set_bit(dlm->node_num, mle->maybe_map);
852 __dlm_insert_mle(dlm, mle);
853
854 /* still holding the dlm spinlock, check the recovery map
855 * to see if there are any nodes that still need to be
856 * considered. these will not appear in the mle nodemap
857 * but they might own this lockres. wait on them. */
858 bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
859 if (bit < O2NM_MAX_NODES) {
860 mlog(0, "%s: res %.*s, At least one node (%d) "
861 "to recover before lock mastery can begin\n",
862 dlm->name, namelen, (char *)lockid, bit);
863 wait_on_recovery = 1;
864 }
865 }
866
867 /* at this point there is either a DLM_MLE_BLOCK or a
868 * DLM_MLE_MASTER on the master list, so it's safe to add the
869 * lockres to the hashtable. anyone who finds the lock will
870 * still have to wait on the IN_PROGRESS. */
871
872 /* finally add the lockres to its hash bucket */
873 __dlm_insert_lockres(dlm, res);
874
875 /* since this lockres is new it doesn't not require the spinlock */
876 __dlm_lockres_grab_inflight_ref(dlm, res);
877
878 /* get an extra ref on the mle in case this is a BLOCK
879 * if so, the creator of the BLOCK may try to put the last
880 * ref at this time in the assert master handler, so we
881 * need an extra one to keep from a bad ptr deref. */
882 dlm_get_mle_inuse(mle);
883 spin_unlock(&dlm->master_lock);
884 spin_unlock(&dlm->spinlock);
885
886 redo_request:
887 while (wait_on_recovery) {
888 /* any cluster changes that occurred after dropping the
889 * dlm spinlock would be detectable be a change on the mle,
890 * so we only need to clear out the recovery map once. */
891 if (dlm_is_recovery_lock(lockid, namelen)) {
892 mlog(0, "%s: Recovery map is not empty, but must "
893 "master $RECOVERY lock now\n", dlm->name);
894 if (!dlm_pre_master_reco_lockres(dlm, res))
895 wait_on_recovery = 0;
896 else {
897 mlog(0, "%s: waiting 500ms for heartbeat state "
898 "change\n", dlm->name);
899 msleep(500);
900 }
901 continue;
902 }
903
904 dlm_kick_recovery_thread(dlm);
905 msleep(1000);
906 dlm_wait_for_recovery(dlm);
907
908 spin_lock(&dlm->spinlock);
909 bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
910 if (bit < O2NM_MAX_NODES) {
911 mlog(0, "%s: res %.*s, At least one node (%d) "
912 "to recover before lock mastery can begin\n",
913 dlm->name, namelen, (char *)lockid, bit);
914 wait_on_recovery = 1;
915 } else
916 wait_on_recovery = 0;
917 spin_unlock(&dlm->spinlock);
918
919 if (wait_on_recovery)
920 dlm_wait_for_node_recovery(dlm, bit, 10000);
921 }
922
923 /* must wait for lock to be mastered elsewhere */
924 if (blocked)
925 goto wait;
926
927 ret = -EINVAL;
928 dlm_node_iter_init(mle->vote_map, &iter);
929 while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
930 ret = dlm_do_master_request(res, mle, nodenum);
931 if (ret < 0)
932 mlog_errno(ret);
933 if (mle->master != O2NM_MAX_NODES) {
934 /* found a master ! */
935 if (mle->master <= nodenum)
936 break;
937 /* if our master request has not reached the master
938 * yet, keep going until it does. this is how the
939 * master will know that asserts are needed back to
940 * the lower nodes. */
941 mlog(0, "%s: res %.*s, Requests only up to %u but "
942 "master is %u, keep going\n", dlm->name, namelen,
943 lockid, nodenum, mle->master);
944 }
945 }
946
947 wait:
948 /* keep going until the response map includes all nodes */
949 ret = dlm_wait_for_lock_mastery(dlm, res, mle, &blocked);
950 if (ret < 0) {
951 wait_on_recovery = 1;
952 mlog(0, "%s: res %.*s, Node map changed, redo the master "
953 "request now, blocked=%d\n", dlm->name, res->lockname.len,
954 res->lockname.name, blocked);
955 if (++tries > 20) {
956 mlog(ML_ERROR, "%s: res %.*s, Spinning on "
957 "dlm_wait_for_lock_mastery, blocked = %d\n",
958 dlm->name, res->lockname.len,
959 res->lockname.name, blocked);
960 dlm_print_one_lock_resource(res);
961 dlm_print_one_mle(mle);
962 tries = 0;
963 }
964 goto redo_request;
965 }
966
967 mlog(0, "%s: res %.*s, Mastered by %u\n", dlm->name, res->lockname.len,
968 res->lockname.name, res->owner);
969 /* make sure we never continue without this */
970 BUG_ON(res->owner == O2NM_MAX_NODES);
971
972 /* master is known, detach if not already detached */
973 dlm_mle_detach_hb_events(dlm, mle);
974 dlm_put_mle(mle);
975 /* put the extra ref */
976 dlm_put_mle_inuse(mle);
977
978 wake_waiters:
979 spin_lock(&res->spinlock);
980 res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
981 spin_unlock(&res->spinlock);
982 wake_up(&res->wq);
983
984 leave:
985 /* need to free the unused mle */
986 if (alloc_mle)
987 kmem_cache_free(dlm_mle_cache, alloc_mle);
988
989 return res;
990 }
991
992
993 #define DLM_MASTERY_TIMEOUT_MS 5000
994
995 static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
996 struct dlm_lock_resource *res,
997 struct dlm_master_list_entry *mle,
998 int *blocked)
999 {
1000 u8 m;
1001 int ret, bit;
1002 int map_changed, voting_done;
1003 int assert, sleep;
1004
1005 recheck:
1006 ret = 0;
1007 assert = 0;
1008
1009 /* check if another node has already become the owner */
1010 spin_lock(&res->spinlock);
1011 if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1012 mlog(0, "%s:%.*s: owner is suddenly %u\n", dlm->name,
1013 res->lockname.len, res->lockname.name, res->owner);
1014 spin_unlock(&res->spinlock);
1015 /* this will cause the master to re-assert across
1016 * the whole cluster, freeing up mles */
1017 if (res->owner != dlm->node_num) {
1018 ret = dlm_do_master_request(res, mle, res->owner);
1019 if (ret < 0) {
1020 /* give recovery a chance to run */
1021 mlog(ML_ERROR, "link to %u went down?: %d\n", res->owner, ret);
1022 msleep(500);
1023 goto recheck;
1024 }
1025 }
1026 ret = 0;
1027 goto leave;
1028 }
1029 spin_unlock(&res->spinlock);
1030
1031 spin_lock(&mle->spinlock);
1032 m = mle->master;
1033 map_changed = (memcmp(mle->vote_map, mle->node_map,
1034 sizeof(mle->vote_map)) != 0);
1035 voting_done = (memcmp(mle->vote_map, mle->response_map,
1036 sizeof(mle->vote_map)) == 0);
1037
1038 /* restart if we hit any errors */
1039 if (map_changed) {
1040 int b;
1041 mlog(0, "%s: %.*s: node map changed, restarting\n",
1042 dlm->name, res->lockname.len, res->lockname.name);
1043 ret = dlm_restart_lock_mastery(dlm, res, mle, *blocked);
1044 b = (mle->type == DLM_MLE_BLOCK);
1045 if ((*blocked && !b) || (!*blocked && b)) {
1046 mlog(0, "%s:%.*s: status change: old=%d new=%d\n",
1047 dlm->name, res->lockname.len, res->lockname.name,
1048 *blocked, b);
1049 *blocked = b;
1050 }
1051 spin_unlock(&mle->spinlock);
1052 if (ret < 0) {
1053 mlog_errno(ret);
1054 goto leave;
1055 }
1056 mlog(0, "%s:%.*s: restart lock mastery succeeded, "
1057 "rechecking now\n", dlm->name, res->lockname.len,
1058 res->lockname.name);
1059 goto recheck;
1060 } else {
1061 if (!voting_done) {
1062 mlog(0, "map not changed and voting not done "
1063 "for %s:%.*s\n", dlm->name, res->lockname.len,
1064 res->lockname.name);
1065 }
1066 }
1067
1068 if (m != O2NM_MAX_NODES) {
1069 /* another node has done an assert!
1070 * all done! */
1071 sleep = 0;
1072 } else {
1073 sleep = 1;
1074 /* have all nodes responded? */
1075 if (voting_done && !*blocked) {
1076 bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
1077 if (dlm->node_num <= bit) {
1078 /* my node number is lowest.
1079 * now tell other nodes that I am
1080 * mastering this. */
1081 mle->master = dlm->node_num;
1082 /* ref was grabbed in get_lock_resource
1083 * will be dropped in dlmlock_master */
1084 assert = 1;
1085 sleep = 0;
1086 }
1087 /* if voting is done, but we have not received
1088 * an assert master yet, we must sleep */
1089 }
1090 }
1091
1092 spin_unlock(&mle->spinlock);
1093
1094 /* sleep if we haven't finished voting yet */
1095 if (sleep) {
1096 unsigned long timeo = msecs_to_jiffies(DLM_MASTERY_TIMEOUT_MS);
1097
1098 /*
1099 if (atomic_read(&mle->mle_refs.refcount) < 2)
1100 mlog(ML_ERROR, "mle (%p) refs=%d, name=%.*s\n", mle,
1101 atomic_read(&mle->mle_refs.refcount),
1102 res->lockname.len, res->lockname.name);
1103 */
1104 atomic_set(&mle->woken, 0);
1105 (void)wait_event_timeout(mle->wq,
1106 (atomic_read(&mle->woken) == 1),
1107 timeo);
1108 if (res->owner == O2NM_MAX_NODES) {
1109 mlog(0, "%s:%.*s: waiting again\n", dlm->name,
1110 res->lockname.len, res->lockname.name);
1111 goto recheck;
1112 }
1113 mlog(0, "done waiting, master is %u\n", res->owner);
1114 ret = 0;
1115 goto leave;
1116 }
1117
1118 ret = 0; /* done */
1119 if (assert) {
1120 m = dlm->node_num;
1121 mlog(0, "about to master %.*s here, this=%u\n",
1122 res->lockname.len, res->lockname.name, m);
1123 ret = dlm_do_assert_master(dlm, res, mle->vote_map, 0);
1124 if (ret) {
1125 /* This is a failure in the network path,
1126 * not in the response to the assert_master
1127 * (any nonzero response is a BUG on this node).
1128 * Most likely a socket just got disconnected
1129 * due to node death. */
1130 mlog_errno(ret);
1131 }
1132 /* no longer need to restart lock mastery.
1133 * all living nodes have been contacted. */
1134 ret = 0;
1135 }
1136
1137 /* set the lockres owner */
1138 spin_lock(&res->spinlock);
1139 /* mastery reference obtained either during
1140 * assert_master_handler or in get_lock_resource */
1141 dlm_change_lockres_owner(dlm, res, m);
1142 spin_unlock(&res->spinlock);
1143
1144 leave:
1145 return ret;
1146 }
1147
1148 struct dlm_bitmap_diff_iter
1149 {
1150 int curnode;
1151 unsigned long *orig_bm;
1152 unsigned long *cur_bm;
1153 unsigned long diff_bm[BITS_TO_LONGS(O2NM_MAX_NODES)];
1154 };
1155
1156 enum dlm_node_state_change
1157 {
1158 NODE_DOWN = -1,
1159 NODE_NO_CHANGE = 0,
1160 NODE_UP
1161 };
1162
1163 static void dlm_bitmap_diff_iter_init(struct dlm_bitmap_diff_iter *iter,
1164 unsigned long *orig_bm,
1165 unsigned long *cur_bm)
1166 {
1167 unsigned long p1, p2;
1168 int i;
1169
1170 iter->curnode = -1;
1171 iter->orig_bm = orig_bm;
1172 iter->cur_bm = cur_bm;
1173
1174 for (i = 0; i < BITS_TO_LONGS(O2NM_MAX_NODES); i++) {
1175 p1 = *(iter->orig_bm + i);
1176 p2 = *(iter->cur_bm + i);
1177 iter->diff_bm[i] = (p1 & ~p2) | (p2 & ~p1);
1178 }
1179 }
1180
1181 static int dlm_bitmap_diff_iter_next(struct dlm_bitmap_diff_iter *iter,
1182 enum dlm_node_state_change *state)
1183 {
1184 int bit;
1185
1186 if (iter->curnode >= O2NM_MAX_NODES)
1187 return -ENOENT;
1188
1189 bit = find_next_bit(iter->diff_bm, O2NM_MAX_NODES,
1190 iter->curnode+1);
1191 if (bit >= O2NM_MAX_NODES) {
1192 iter->curnode = O2NM_MAX_NODES;
1193 return -ENOENT;
1194 }
1195
1196 /* if it was there in the original then this node died */
1197 if (test_bit(bit, iter->orig_bm))
1198 *state = NODE_DOWN;
1199 else
1200 *state = NODE_UP;
1201
1202 iter->curnode = bit;
1203 return bit;
1204 }
1205
1206
1207 static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
1208 struct dlm_lock_resource *res,
1209 struct dlm_master_list_entry *mle,
1210 int blocked)
1211 {
1212 struct dlm_bitmap_diff_iter bdi;
1213 enum dlm_node_state_change sc;
1214 int node;
1215 int ret = 0;
1216
1217 mlog(0, "something happened such that the "
1218 "master process may need to be restarted!\n");
1219
1220 assert_spin_locked(&mle->spinlock);
1221
1222 dlm_bitmap_diff_iter_init(&bdi, mle->vote_map, mle->node_map);
1223 node = dlm_bitmap_diff_iter_next(&bdi, &sc);
1224 while (node >= 0) {
1225 if (sc == NODE_UP) {
1226 /* a node came up. clear any old vote from
1227 * the response map and set it in the vote map
1228 * then restart the mastery. */
1229 mlog(ML_NOTICE, "node %d up while restarting\n", node);
1230
1231 /* redo the master request, but only for the new node */
1232 mlog(0, "sending request to new node\n");
1233 clear_bit(node, mle->response_map);
1234 set_bit(node, mle->vote_map);
1235 } else {
1236 mlog(ML_ERROR, "node down! %d\n", node);
1237 if (blocked) {
1238 int lowest = find_next_bit(mle->maybe_map,
1239 O2NM_MAX_NODES, 0);
1240
1241 /* act like it was never there */
1242 clear_bit(node, mle->maybe_map);
1243
1244 if (node == lowest) {
1245 mlog(0, "expected master %u died"
1246 " while this node was blocked "
1247 "waiting on it!\n", node);
1248 lowest = find_next_bit(mle->maybe_map,
1249 O2NM_MAX_NODES,
1250 lowest+1);
1251 if (lowest < O2NM_MAX_NODES) {
1252 mlog(0, "%s:%.*s:still "
1253 "blocked. waiting on %u "
1254 "now\n", dlm->name,
1255 res->lockname.len,
1256 res->lockname.name,
1257 lowest);
1258 } else {
1259 /* mle is an MLE_BLOCK, but
1260 * there is now nothing left to
1261 * block on. we need to return
1262 * all the way back out and try
1263 * again with an MLE_MASTER.
1264 * dlm_do_local_recovery_cleanup
1265 * has already run, so the mle
1266 * refcount is ok */
1267 mlog(0, "%s:%.*s: no "
1268 "longer blocking. try to "
1269 "master this here\n",
1270 dlm->name,
1271 res->lockname.len,
1272 res->lockname.name);
1273 mle->type = DLM_MLE_MASTER;
1274 mle->mleres = res;
1275 }
1276 }
1277 }
1278
1279 /* now blank out everything, as if we had never
1280 * contacted anyone */
1281 memset(mle->maybe_map, 0, sizeof(mle->maybe_map));
1282 memset(mle->response_map, 0, sizeof(mle->response_map));
1283 /* reset the vote_map to the current node_map */
1284 memcpy(mle->vote_map, mle->node_map,
1285 sizeof(mle->node_map));
1286 /* put myself into the maybe map */
1287 if (mle->type != DLM_MLE_BLOCK)
1288 set_bit(dlm->node_num, mle->maybe_map);
1289 }
1290 ret = -EAGAIN;
1291 node = dlm_bitmap_diff_iter_next(&bdi, &sc);
1292 }
1293 return ret;
1294 }
1295
1296
1297 /*
1298 * DLM_MASTER_REQUEST_MSG
1299 *
1300 * returns: 0 on success,
1301 * -errno on a network error
1302 *
1303 * on error, the caller should assume the target node is "dead"
1304 *
1305 */
1306
1307 static int dlm_do_master_request(struct dlm_lock_resource *res,
1308 struct dlm_master_list_entry *mle, int to)
1309 {
1310 struct dlm_ctxt *dlm = mle->dlm;
1311 struct dlm_master_request request;
1312 int ret, response=0, resend;
1313
1314 memset(&request, 0, sizeof(request));
1315 request.node_idx = dlm->node_num;
1316
1317 BUG_ON(mle->type == DLM_MLE_MIGRATION);
1318
1319 request.namelen = (u8)mle->mnamelen;
1320 memcpy(request.name, mle->mname, request.namelen);
1321
1322 again:
1323 ret = o2net_send_message(DLM_MASTER_REQUEST_MSG, dlm->key, &request,
1324 sizeof(request), to, &response);
1325 if (ret < 0) {
1326 if (ret == -ESRCH) {
1327 /* should never happen */
1328 mlog(ML_ERROR, "TCP stack not ready!\n");
1329 BUG();
1330 } else if (ret == -EINVAL) {
1331 mlog(ML_ERROR, "bad args passed to o2net!\n");
1332 BUG();
1333 } else if (ret == -ENOMEM) {
1334 mlog(ML_ERROR, "out of memory while trying to send "
1335 "network message! retrying\n");
1336 /* this is totally crude */
1337 msleep(50);
1338 goto again;
1339 } else if (!dlm_is_host_down(ret)) {
1340 /* not a network error. bad. */
1341 mlog_errno(ret);
1342 mlog(ML_ERROR, "unhandled error!");
1343 BUG();
1344 }
1345 /* all other errors should be network errors,
1346 * and likely indicate node death */
1347 mlog(ML_ERROR, "link to %d went down!\n", to);
1348 goto out;
1349 }
1350
1351 ret = 0;
1352 resend = 0;
1353 spin_lock(&mle->spinlock);
1354 switch (response) {
1355 case DLM_MASTER_RESP_YES:
1356 set_bit(to, mle->response_map);
1357 mlog(0, "node %u is the master, response=YES\n", to);
1358 mlog(0, "%s:%.*s: master node %u now knows I have a "
1359 "reference\n", dlm->name, res->lockname.len,
1360 res->lockname.name, to);
1361 mle->master = to;
1362 break;
1363 case DLM_MASTER_RESP_NO:
1364 mlog(0, "node %u not master, response=NO\n", to);
1365 set_bit(to, mle->response_map);
1366 break;
1367 case DLM_MASTER_RESP_MAYBE:
1368 mlog(0, "node %u not master, response=MAYBE\n", to);
1369 set_bit(to, mle->response_map);
1370 set_bit(to, mle->maybe_map);
1371 break;
1372 case DLM_MASTER_RESP_ERROR:
1373 mlog(0, "node %u hit an error, resending\n", to);
1374 resend = 1;
1375 response = 0;
1376 break;
1377 default:
1378 mlog(ML_ERROR, "bad response! %u\n", response);
1379 BUG();
1380 }
1381 spin_unlock(&mle->spinlock);
1382 if (resend) {
1383 /* this is also totally crude */
1384 msleep(50);
1385 goto again;
1386 }
1387
1388 out:
1389 return ret;
1390 }
1391
1392 /*
1393 * locks that can be taken here:
1394 * dlm->spinlock
1395 * res->spinlock
1396 * mle->spinlock
1397 * dlm->master_list
1398 *
1399 * if possible, TRIM THIS DOWN!!!
1400 */
1401 int dlm_master_request_handler(struct o2net_msg *msg, u32 len, void *data,
1402 void **ret_data)
1403 {
1404 u8 response = DLM_MASTER_RESP_MAYBE;
1405 struct dlm_ctxt *dlm = data;
1406 struct dlm_lock_resource *res = NULL;
1407 struct dlm_master_request *request = (struct dlm_master_request *) msg->buf;
1408 struct dlm_master_list_entry *mle = NULL, *tmpmle = NULL;
1409 char *name;
1410 unsigned int namelen, hash;
1411 int found, ret;
1412 int set_maybe;
1413 int dispatch_assert = 0;
1414
1415 if (!dlm_grab(dlm))
1416 return DLM_MASTER_RESP_NO;
1417
1418 if (!dlm_domain_fully_joined(dlm)) {
1419 response = DLM_MASTER_RESP_NO;
1420 goto send_response;
1421 }
1422
1423 name = request->name;
1424 namelen = request->namelen;
1425 hash = dlm_lockid_hash(name, namelen);
1426
1427 if (namelen > DLM_LOCKID_NAME_MAX) {
1428 response = DLM_IVBUFLEN;
1429 goto send_response;
1430 }
1431
1432 way_up_top:
1433 spin_lock(&dlm->spinlock);
1434 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
1435 if (res) {
1436 spin_unlock(&dlm->spinlock);
1437
1438 /* take care of the easy cases up front */
1439 spin_lock(&res->spinlock);
1440 if (res->state & (DLM_LOCK_RES_RECOVERING|
1441 DLM_LOCK_RES_MIGRATING)) {
1442 spin_unlock(&res->spinlock);
1443 mlog(0, "returning DLM_MASTER_RESP_ERROR since res is "
1444 "being recovered/migrated\n");
1445 response = DLM_MASTER_RESP_ERROR;
1446 if (mle)
1447 kmem_cache_free(dlm_mle_cache, mle);
1448 goto send_response;
1449 }
1450
1451 if (res->owner == dlm->node_num) {
1452 dlm_lockres_set_refmap_bit(dlm, res, request->node_idx);
1453 spin_unlock(&res->spinlock);
1454 response = DLM_MASTER_RESP_YES;
1455 if (mle)
1456 kmem_cache_free(dlm_mle_cache, mle);
1457
1458 /* this node is the owner.
1459 * there is some extra work that needs to
1460 * happen now. the requesting node has
1461 * caused all nodes up to this one to
1462 * create mles. this node now needs to
1463 * go back and clean those up. */
1464 dispatch_assert = 1;
1465 goto send_response;
1466 } else if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1467 spin_unlock(&res->spinlock);
1468 // mlog(0, "node %u is the master\n", res->owner);
1469 response = DLM_MASTER_RESP_NO;
1470 if (mle)
1471 kmem_cache_free(dlm_mle_cache, mle);
1472 goto send_response;
1473 }
1474
1475 /* ok, there is no owner. either this node is
1476 * being blocked, or it is actively trying to
1477 * master this lock. */
1478 if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
1479 mlog(ML_ERROR, "lock with no owner should be "
1480 "in-progress!\n");
1481 BUG();
1482 }
1483
1484 // mlog(0, "lockres is in progress...\n");
1485 spin_lock(&dlm->master_lock);
1486 found = dlm_find_mle(dlm, &tmpmle, name, namelen);
1487 if (!found) {
1488 mlog(ML_ERROR, "no mle found for this lock!\n");
1489 BUG();
1490 }
1491 set_maybe = 1;
1492 spin_lock(&tmpmle->spinlock);
1493 if (tmpmle->type == DLM_MLE_BLOCK) {
1494 // mlog(0, "this node is waiting for "
1495 // "lockres to be mastered\n");
1496 response = DLM_MASTER_RESP_NO;
1497 } else if (tmpmle->type == DLM_MLE_MIGRATION) {
1498 mlog(0, "node %u is master, but trying to migrate to "
1499 "node %u.\n", tmpmle->master, tmpmle->new_master);
1500 if (tmpmle->master == dlm->node_num) {
1501 mlog(ML_ERROR, "no owner on lockres, but this "
1502 "node is trying to migrate it to %u?!\n",
1503 tmpmle->new_master);
1504 BUG();
1505 } else {
1506 /* the real master can respond on its own */
1507 response = DLM_MASTER_RESP_NO;
1508 }
1509 } else if (tmpmle->master != DLM_LOCK_RES_OWNER_UNKNOWN) {
1510 set_maybe = 0;
1511 if (tmpmle->master == dlm->node_num) {
1512 response = DLM_MASTER_RESP_YES;
1513 /* this node will be the owner.
1514 * go back and clean the mles on any
1515 * other nodes */
1516 dispatch_assert = 1;
1517 dlm_lockres_set_refmap_bit(dlm, res,
1518 request->node_idx);
1519 } else
1520 response = DLM_MASTER_RESP_NO;
1521 } else {
1522 // mlog(0, "this node is attempting to "
1523 // "master lockres\n");
1524 response = DLM_MASTER_RESP_MAYBE;
1525 }
1526 if (set_maybe)
1527 set_bit(request->node_idx, tmpmle->maybe_map);
1528 spin_unlock(&tmpmle->spinlock);
1529
1530 spin_unlock(&dlm->master_lock);
1531 spin_unlock(&res->spinlock);
1532
1533 /* keep the mle attached to heartbeat events */
1534 dlm_put_mle(tmpmle);
1535 if (mle)
1536 kmem_cache_free(dlm_mle_cache, mle);
1537 goto send_response;
1538 }
1539
1540 /*
1541 * lockres doesn't exist on this node
1542 * if there is an MLE_BLOCK, return NO
1543 * if there is an MLE_MASTER, return MAYBE
1544 * otherwise, add an MLE_BLOCK, return NO
1545 */
1546 spin_lock(&dlm->master_lock);
1547 found = dlm_find_mle(dlm, &tmpmle, name, namelen);
1548 if (!found) {
1549 /* this lockid has never been seen on this node yet */
1550 // mlog(0, "no mle found\n");
1551 if (!mle) {
1552 spin_unlock(&dlm->master_lock);
1553 spin_unlock(&dlm->spinlock);
1554
1555 mle = kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
1556 if (!mle) {
1557 response = DLM_MASTER_RESP_ERROR;
1558 mlog_errno(-ENOMEM);
1559 goto send_response;
1560 }
1561 goto way_up_top;
1562 }
1563
1564 // mlog(0, "this is second time thru, already allocated, "
1565 // "add the block.\n");
1566 dlm_init_mle(mle, DLM_MLE_BLOCK, dlm, NULL, name, namelen);
1567 set_bit(request->node_idx, mle->maybe_map);
1568 __dlm_insert_mle(dlm, mle);
1569 response = DLM_MASTER_RESP_NO;
1570 } else {
1571 // mlog(0, "mle was found\n");
1572 set_maybe = 1;
1573 spin_lock(&tmpmle->spinlock);
1574 if (tmpmle->master == dlm->node_num) {
1575 mlog(ML_ERROR, "no lockres, but an mle with this node as master!\n");
1576 BUG();
1577 }
1578 if (tmpmle->type == DLM_MLE_BLOCK)
1579 response = DLM_MASTER_RESP_NO;
1580 else if (tmpmle->type == DLM_MLE_MIGRATION) {
1581 mlog(0, "migration mle was found (%u->%u)\n",
1582 tmpmle->master, tmpmle->new_master);
1583 /* real master can respond on its own */
1584 response = DLM_MASTER_RESP_NO;
1585 } else
1586 response = DLM_MASTER_RESP_MAYBE;
1587 if (set_maybe)
1588 set_bit(request->node_idx, tmpmle->maybe_map);
1589 spin_unlock(&tmpmle->spinlock);
1590 }
1591 spin_unlock(&dlm->master_lock);
1592 spin_unlock(&dlm->spinlock);
1593
1594 if (found) {
1595 /* keep the mle attached to heartbeat events */
1596 dlm_put_mle(tmpmle);
1597 }
1598 send_response:
1599 /*
1600 * __dlm_lookup_lockres() grabbed a reference to this lockres.
1601 * The reference is released by dlm_assert_master_worker() under
1602 * the call to dlm_dispatch_assert_master(). If
1603 * dlm_assert_master_worker() isn't called, we drop it here.
1604 */
1605 if (dispatch_assert) {
1606 if (response != DLM_MASTER_RESP_YES)
1607 mlog(ML_ERROR, "invalid response %d\n", response);
1608 if (!res) {
1609 mlog(ML_ERROR, "bad lockres while trying to assert!\n");
1610 BUG();
1611 }
1612 mlog(0, "%u is the owner of %.*s, cleaning everyone else\n",
1613 dlm->node_num, res->lockname.len, res->lockname.name);
1614 ret = dlm_dispatch_assert_master(dlm, res, 0, request->node_idx,
1615 DLM_ASSERT_MASTER_MLE_CLEANUP);
1616 if (ret < 0) {
1617 mlog(ML_ERROR, "failed to dispatch assert master work\n");
1618 response = DLM_MASTER_RESP_ERROR;
1619 dlm_lockres_put(res);
1620 }
1621 } else {
1622 if (res)
1623 dlm_lockres_put(res);
1624 }
1625
1626 dlm_put(dlm);
1627 return response;
1628 }
1629
1630 /*
1631 * DLM_ASSERT_MASTER_MSG
1632 */
1633
1634
1635 /*
1636 * NOTE: this can be used for debugging
1637 * can periodically run all locks owned by this node
1638 * and re-assert across the cluster...
1639 */
1640 static int dlm_do_assert_master(struct dlm_ctxt *dlm,
1641 struct dlm_lock_resource *res,
1642 void *nodemap, u32 flags)
1643 {
1644 struct dlm_assert_master assert;
1645 int to, tmpret;
1646 struct dlm_node_iter iter;
1647 int ret = 0;
1648 int reassert;
1649 const char *lockname = res->lockname.name;
1650 unsigned int namelen = res->lockname.len;
1651
1652 BUG_ON(namelen > O2NM_MAX_NAME_LEN);
1653
1654 spin_lock(&res->spinlock);
1655 res->state |= DLM_LOCK_RES_SETREF_INPROG;
1656 spin_unlock(&res->spinlock);
1657
1658 again:
1659 reassert = 0;
1660
1661 /* note that if this nodemap is empty, it returns 0 */
1662 dlm_node_iter_init(nodemap, &iter);
1663 while ((to = dlm_node_iter_next(&iter)) >= 0) {
1664 int r = 0;
1665 struct dlm_master_list_entry *mle = NULL;
1666
1667 mlog(0, "sending assert master to %d (%.*s)\n", to,
1668 namelen, lockname);
1669 memset(&assert, 0, sizeof(assert));
1670 assert.node_idx = dlm->node_num;
1671 assert.namelen = namelen;
1672 memcpy(assert.name, lockname, namelen);
1673 assert.flags = cpu_to_be32(flags);
1674
1675 tmpret = o2net_send_message(DLM_ASSERT_MASTER_MSG, dlm->key,
1676 &assert, sizeof(assert), to, &r);
1677 if (tmpret < 0) {
1678 mlog(ML_ERROR, "Error %d when sending message %u (key "
1679 "0x%x) to node %u\n", tmpret,
1680 DLM_ASSERT_MASTER_MSG, dlm->key, to);
1681 if (!dlm_is_host_down(tmpret)) {
1682 mlog(ML_ERROR, "unhandled error=%d!\n", tmpret);
1683 BUG();
1684 }
1685 /* a node died. finish out the rest of the nodes. */
1686 mlog(0, "link to %d went down!\n", to);
1687 /* any nonzero status return will do */
1688 ret = tmpret;
1689 r = 0;
1690 } else if (r < 0) {
1691 /* ok, something horribly messed. kill thyself. */
1692 mlog(ML_ERROR,"during assert master of %.*s to %u, "
1693 "got %d.\n", namelen, lockname, to, r);
1694 spin_lock(&dlm->spinlock);
1695 spin_lock(&dlm->master_lock);
1696 if (dlm_find_mle(dlm, &mle, (char *)lockname,
1697 namelen)) {
1698 dlm_print_one_mle(mle);
1699 __dlm_put_mle(mle);
1700 }
1701 spin_unlock(&dlm->master_lock);
1702 spin_unlock(&dlm->spinlock);
1703 BUG();
1704 }
1705
1706 if (r & DLM_ASSERT_RESPONSE_REASSERT &&
1707 !(r & DLM_ASSERT_RESPONSE_MASTERY_REF)) {
1708 mlog(ML_ERROR, "%.*s: very strange, "
1709 "master MLE but no lockres on %u\n",
1710 namelen, lockname, to);
1711 }
1712
1713 if (r & DLM_ASSERT_RESPONSE_REASSERT) {
1714 mlog(0, "%.*s: node %u create mles on other "
1715 "nodes and requests a re-assert\n",
1716 namelen, lockname, to);
1717 reassert = 1;
1718 }
1719 if (r & DLM_ASSERT_RESPONSE_MASTERY_REF) {
1720 mlog(0, "%.*s: node %u has a reference to this "
1721 "lockres, set the bit in the refmap\n",
1722 namelen, lockname, to);
1723 spin_lock(&res->spinlock);
1724 dlm_lockres_set_refmap_bit(dlm, res, to);
1725 spin_unlock(&res->spinlock);
1726 }
1727 }
1728
1729 if (reassert)
1730 goto again;
1731
1732 spin_lock(&res->spinlock);
1733 res->state &= ~DLM_LOCK_RES_SETREF_INPROG;
1734 spin_unlock(&res->spinlock);
1735 wake_up(&res->wq);
1736
1737 return ret;
1738 }
1739
1740 /*
1741 * locks that can be taken here:
1742 * dlm->spinlock
1743 * res->spinlock
1744 * mle->spinlock
1745 * dlm->master_list
1746 *
1747 * if possible, TRIM THIS DOWN!!!
1748 */
1749 int dlm_assert_master_handler(struct o2net_msg *msg, u32 len, void *data,
1750 void **ret_data)
1751 {
1752 struct dlm_ctxt *dlm = data;
1753 struct dlm_master_list_entry *mle = NULL;
1754 struct dlm_assert_master *assert = (struct dlm_assert_master *)msg->buf;
1755 struct dlm_lock_resource *res = NULL;
1756 char *name;
1757 unsigned int namelen, hash;
1758 u32 flags;
1759 int master_request = 0, have_lockres_ref = 0;
1760 int ret = 0;
1761
1762 if (!dlm_grab(dlm))
1763 return 0;
1764
1765 name = assert->name;
1766 namelen = assert->namelen;
1767 hash = dlm_lockid_hash(name, namelen);
1768 flags = be32_to_cpu(assert->flags);
1769
1770 if (namelen > DLM_LOCKID_NAME_MAX) {
1771 mlog(ML_ERROR, "Invalid name length!");
1772 goto done;
1773 }
1774
1775 spin_lock(&dlm->spinlock);
1776
1777 if (flags)
1778 mlog(0, "assert_master with flags: %u\n", flags);
1779
1780 /* find the MLE */
1781 spin_lock(&dlm->master_lock);
1782 if (!dlm_find_mle(dlm, &mle, name, namelen)) {
1783 /* not an error, could be master just re-asserting */
1784 mlog(0, "just got an assert_master from %u, but no "
1785 "MLE for it! (%.*s)\n", assert->node_idx,
1786 namelen, name);
1787 } else {
1788 int bit = find_next_bit (mle->maybe_map, O2NM_MAX_NODES, 0);
1789 if (bit >= O2NM_MAX_NODES) {
1790 /* not necessarily an error, though less likely.
1791 * could be master just re-asserting. */
1792 mlog(0, "no bits set in the maybe_map, but %u "
1793 "is asserting! (%.*s)\n", assert->node_idx,
1794 namelen, name);
1795 } else if (bit != assert->node_idx) {
1796 if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
1797 mlog(0, "master %u was found, %u should "
1798 "back off\n", assert->node_idx, bit);
1799 } else {
1800 /* with the fix for bug 569, a higher node
1801 * number winning the mastery will respond
1802 * YES to mastery requests, but this node
1803 * had no way of knowing. let it pass. */
1804 mlog(0, "%u is the lowest node, "
1805 "%u is asserting. (%.*s) %u must "
1806 "have begun after %u won.\n", bit,
1807 assert->node_idx, namelen, name, bit,
1808 assert->node_idx);
1809 }
1810 }
1811 if (mle->type == DLM_MLE_MIGRATION) {
1812 if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
1813 mlog(0, "%s:%.*s: got cleanup assert"
1814 " from %u for migration\n",
1815 dlm->name, namelen, name,
1816 assert->node_idx);
1817 } else if (!(flags & DLM_ASSERT_MASTER_FINISH_MIGRATION)) {
1818 mlog(0, "%s:%.*s: got unrelated assert"
1819 " from %u for migration, ignoring\n",
1820 dlm->name, namelen, name,
1821 assert->node_idx);
1822 __dlm_put_mle(mle);
1823 spin_unlock(&dlm->master_lock);
1824 spin_unlock(&dlm->spinlock);
1825 goto done;
1826 }
1827 }
1828 }
1829 spin_unlock(&dlm->master_lock);
1830
1831 /* ok everything checks out with the MLE
1832 * now check to see if there is a lockres */
1833 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
1834 if (res) {
1835 spin_lock(&res->spinlock);
1836 if (res->state & DLM_LOCK_RES_RECOVERING) {
1837 mlog(ML_ERROR, "%u asserting but %.*s is "
1838 "RECOVERING!\n", assert->node_idx, namelen, name);
1839 goto kill;
1840 }
1841 if (!mle) {
1842 if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN &&
1843 res->owner != assert->node_idx) {
1844 mlog(ML_ERROR, "DIE! Mastery assert from %u, "
1845 "but current owner is %u! (%.*s)\n",
1846 assert->node_idx, res->owner, namelen,
1847 name);
1848 __dlm_print_one_lock_resource(res);
1849 BUG();
1850 }
1851 } else if (mle->type != DLM_MLE_MIGRATION) {
1852 if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1853 /* owner is just re-asserting */
1854 if (res->owner == assert->node_idx) {
1855 mlog(0, "owner %u re-asserting on "
1856 "lock %.*s\n", assert->node_idx,
1857 namelen, name);
1858 goto ok;
1859 }
1860 mlog(ML_ERROR, "got assert_master from "
1861 "node %u, but %u is the owner! "
1862 "(%.*s)\n", assert->node_idx,
1863 res->owner, namelen, name);
1864 goto kill;
1865 }
1866 if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
1867 mlog(ML_ERROR, "got assert from %u, but lock "
1868 "with no owner should be "
1869 "in-progress! (%.*s)\n",
1870 assert->node_idx,
1871 namelen, name);
1872 goto kill;
1873 }
1874 } else /* mle->type == DLM_MLE_MIGRATION */ {
1875 /* should only be getting an assert from new master */
1876 if (assert->node_idx != mle->new_master) {
1877 mlog(ML_ERROR, "got assert from %u, but "
1878 "new master is %u, and old master "
1879 "was %u (%.*s)\n",
1880 assert->node_idx, mle->new_master,
1881 mle->master, namelen, name);
1882 goto kill;
1883 }
1884
1885 }
1886 ok:
1887 spin_unlock(&res->spinlock);
1888 }
1889
1890 // mlog(0, "woo! got an assert_master from node %u!\n",
1891 // assert->node_idx);
1892 if (mle) {
1893 int extra_ref = 0;
1894 int nn = -1;
1895 int rr, err = 0;
1896
1897 spin_lock(&mle->spinlock);
1898 if (mle->type == DLM_MLE_BLOCK || mle->type == DLM_MLE_MIGRATION)
1899 extra_ref = 1;
1900 else {
1901 /* MASTER mle: if any bits set in the response map
1902 * then the calling node needs to re-assert to clear
1903 * up nodes that this node contacted */
1904 while ((nn = find_next_bit (mle->response_map, O2NM_MAX_NODES,
1905 nn+1)) < O2NM_MAX_NODES) {
1906 if (nn != dlm->node_num && nn != assert->node_idx)
1907 master_request = 1;
1908 }
1909 }
1910 mle->master = assert->node_idx;
1911 atomic_set(&mle->woken, 1);
1912 wake_up(&mle->wq);
1913 spin_unlock(&mle->spinlock);
1914
1915 if (res) {
1916 int wake = 0;
1917 spin_lock(&res->spinlock);
1918 if (mle->type == DLM_MLE_MIGRATION) {
1919 mlog(0, "finishing off migration of lockres %.*s, "
1920 "from %u to %u\n",
1921 res->lockname.len, res->lockname.name,
1922 dlm->node_num, mle->new_master);
1923 res->state &= ~DLM_LOCK_RES_MIGRATING;
1924 wake = 1;
1925 dlm_change_lockres_owner(dlm, res, mle->new_master);
1926 BUG_ON(res->state & DLM_LOCK_RES_DIRTY);
1927 } else {
1928 dlm_change_lockres_owner(dlm, res, mle->master);
1929 }
1930 spin_unlock(&res->spinlock);
1931 have_lockres_ref = 1;
1932 if (wake)
1933 wake_up(&res->wq);
1934 }
1935
1936 /* master is known, detach if not already detached.
1937 * ensures that only one assert_master call will happen
1938 * on this mle. */
1939 spin_lock(&dlm->master_lock);
1940
1941 rr = atomic_read(&mle->mle_refs.refcount);
1942 if (mle->inuse > 0) {
1943 if (extra_ref && rr < 3)
1944 err = 1;
1945 else if (!extra_ref && rr < 2)
1946 err = 1;
1947 } else {
1948 if (extra_ref && rr < 2)
1949 err = 1;
1950 else if (!extra_ref && rr < 1)
1951 err = 1;
1952 }
1953 if (err) {
1954 mlog(ML_ERROR, "%s:%.*s: got assert master from %u "
1955 "that will mess up this node, refs=%d, extra=%d, "
1956 "inuse=%d\n", dlm->name, namelen, name,
1957 assert->node_idx, rr, extra_ref, mle->inuse);
1958 dlm_print_one_mle(mle);
1959 }
1960 __dlm_unlink_mle(dlm, mle);
1961 __dlm_mle_detach_hb_events(dlm, mle);
1962 __dlm_put_mle(mle);
1963 if (extra_ref) {
1964 /* the assert master message now balances the extra
1965 * ref given by the master / migration request message.
1966 * if this is the last put, it will be removed
1967 * from the list. */
1968 __dlm_put_mle(mle);
1969 }
1970 spin_unlock(&dlm->master_lock);
1971 } else if (res) {
1972 if (res->owner != assert->node_idx) {
1973 mlog(0, "assert_master from %u, but current "
1974 "owner is %u (%.*s), no mle\n", assert->node_idx,
1975 res->owner, namelen, name);
1976 }
1977 }
1978 spin_unlock(&dlm->spinlock);
1979
1980 done:
1981 ret = 0;
1982 if (res) {
1983 spin_lock(&res->spinlock);
1984 res->state |= DLM_LOCK_RES_SETREF_INPROG;
1985 spin_unlock(&res->spinlock);
1986 *ret_data = (void *)res;
1987 }
1988 dlm_put(dlm);
1989 if (master_request) {
1990 mlog(0, "need to tell master to reassert\n");
1991 /* positive. negative would shoot down the node. */
1992 ret |= DLM_ASSERT_RESPONSE_REASSERT;
1993 if (!have_lockres_ref) {
1994 mlog(ML_ERROR, "strange, got assert from %u, MASTER "
1995 "mle present here for %s:%.*s, but no lockres!\n",
1996 assert->node_idx, dlm->name, namelen, name);
1997 }
1998 }
1999 if (have_lockres_ref) {
2000 /* let the master know we have a reference to the lockres */
2001 ret |= DLM_ASSERT_RESPONSE_MASTERY_REF;
2002 mlog(0, "%s:%.*s: got assert from %u, need a ref\n",
2003 dlm->name, namelen, name, assert->node_idx);
2004 }
2005 return ret;
2006
2007 kill:
2008 /* kill the caller! */
2009 mlog(ML_ERROR, "Bad message received from another node. Dumping state "
2010 "and killing the other node now! This node is OK and can continue.\n");
2011 __dlm_print_one_lock_resource(res);
2012 spin_unlock(&res->spinlock);
2013 spin_unlock(&dlm->spinlock);
2014 *ret_data = (void *)res;
2015 dlm_put(dlm);
2016 return -EINVAL;
2017 }
2018
2019 void dlm_assert_master_post_handler(int status, void *data, void *ret_data)
2020 {
2021 struct dlm_lock_resource *res = (struct dlm_lock_resource *)ret_data;
2022
2023 if (ret_data) {
2024 spin_lock(&res->spinlock);
2025 res->state &= ~DLM_LOCK_RES_SETREF_INPROG;
2026 spin_unlock(&res->spinlock);
2027 wake_up(&res->wq);
2028 dlm_lockres_put(res);
2029 }
2030 return;
2031 }
2032
2033 int dlm_dispatch_assert_master(struct dlm_ctxt *dlm,
2034 struct dlm_lock_resource *res,
2035 int ignore_higher, u8 request_from, u32 flags)
2036 {
2037 struct dlm_work_item *item;
2038 item = kzalloc(sizeof(*item), GFP_ATOMIC);
2039 if (!item)
2040 return -ENOMEM;
2041
2042
2043 /* queue up work for dlm_assert_master_worker */
2044 dlm_grab(dlm); /* get an extra ref for the work item */
2045 dlm_init_work_item(dlm, item, dlm_assert_master_worker, NULL);
2046 item->u.am.lockres = res; /* already have a ref */
2047 /* can optionally ignore node numbers higher than this node */
2048 item->u.am.ignore_higher = ignore_higher;
2049 item->u.am.request_from = request_from;
2050 item->u.am.flags = flags;
2051
2052 if (ignore_higher)
2053 mlog(0, "IGNORE HIGHER: %.*s\n", res->lockname.len,
2054 res->lockname.name);
2055
2056 spin_lock(&dlm->work_lock);
2057 list_add_tail(&item->list, &dlm->work_list);
2058 spin_unlock(&dlm->work_lock);
2059
2060 queue_work(dlm->dlm_worker, &dlm->dispatched_work);
2061 return 0;
2062 }
2063
2064 static void dlm_assert_master_worker(struct dlm_work_item *item, void *data)
2065 {
2066 struct dlm_ctxt *dlm = data;
2067 int ret = 0;
2068 struct dlm_lock_resource *res;
2069 unsigned long nodemap[BITS_TO_LONGS(O2NM_MAX_NODES)];
2070 int ignore_higher;
2071 int bit;
2072 u8 request_from;
2073 u32 flags;
2074
2075 dlm = item->dlm;
2076 res = item->u.am.lockres;
2077 ignore_higher = item->u.am.ignore_higher;
2078 request_from = item->u.am.request_from;
2079 flags = item->u.am.flags;
2080
2081 spin_lock(&dlm->spinlock);
2082 memcpy(nodemap, dlm->domain_map, sizeof(nodemap));
2083 spin_unlock(&dlm->spinlock);
2084
2085 clear_bit(dlm->node_num, nodemap);
2086 if (ignore_higher) {
2087 /* if is this just to clear up mles for nodes below
2088 * this node, do not send the message to the original
2089 * caller or any node number higher than this */
2090 clear_bit(request_from, nodemap);
2091 bit = dlm->node_num;
2092 while (1) {
2093 bit = find_next_bit(nodemap, O2NM_MAX_NODES,
2094 bit+1);
2095 if (bit >= O2NM_MAX_NODES)
2096 break;
2097 clear_bit(bit, nodemap);
2098 }
2099 }
2100
2101 /*
2102 * If we're migrating this lock to someone else, we are no
2103 * longer allowed to assert out own mastery. OTOH, we need to
2104 * prevent migration from starting while we're still asserting
2105 * our dominance. The reserved ast delays migration.
2106 */
2107 spin_lock(&res->spinlock);
2108 if (res->state & DLM_LOCK_RES_MIGRATING) {
2109 mlog(0, "Someone asked us to assert mastery, but we're "
2110 "in the middle of migration. Skipping assert, "
2111 "the new master will handle that.\n");
2112 spin_unlock(&res->spinlock);
2113 goto put;
2114 } else
2115 __dlm_lockres_reserve_ast(res);
2116 spin_unlock(&res->spinlock);
2117
2118 /* this call now finishes out the nodemap
2119 * even if one or more nodes die */
2120 mlog(0, "worker about to master %.*s here, this=%u\n",
2121 res->lockname.len, res->lockname.name, dlm->node_num);
2122 ret = dlm_do_assert_master(dlm, res, nodemap, flags);
2123 if (ret < 0) {
2124 /* no need to restart, we are done */
2125 if (!dlm_is_host_down(ret))
2126 mlog_errno(ret);
2127 }
2128
2129 /* Ok, we've asserted ourselves. Let's let migration start. */
2130 dlm_lockres_release_ast(dlm, res);
2131
2132 put:
2133 dlm_lockres_put(res);
2134
2135 mlog(0, "finished with dlm_assert_master_worker\n");
2136 }
2137
2138 /* SPECIAL CASE for the $RECOVERY lock used by the recovery thread.
2139 * We cannot wait for node recovery to complete to begin mastering this
2140 * lockres because this lockres is used to kick off recovery! ;-)
2141 * So, do a pre-check on all living nodes to see if any of those nodes
2142 * think that $RECOVERY is currently mastered by a dead node. If so,
2143 * we wait a short time to allow that node to get notified by its own
2144 * heartbeat stack, then check again. All $RECOVERY lock resources
2145 * mastered by dead nodes are purged when the hearbeat callback is
2146 * fired, so we can know for sure that it is safe to continue once
2147 * the node returns a live node or no node. */
2148 static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
2149 struct dlm_lock_resource *res)
2150 {
2151 struct dlm_node_iter iter;
2152 int nodenum;
2153 int ret = 0;
2154 u8 master = DLM_LOCK_RES_OWNER_UNKNOWN;
2155
2156 spin_lock(&dlm->spinlock);
2157 dlm_node_iter_init(dlm->domain_map, &iter);
2158 spin_unlock(&dlm->spinlock);
2159
2160 while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
2161 /* do not send to self */
2162 if (nodenum == dlm->node_num)
2163 continue;
2164 ret = dlm_do_master_requery(dlm, res, nodenum, &master);
2165 if (ret < 0) {
2166 mlog_errno(ret);
2167 if (!dlm_is_host_down(ret))
2168 BUG();
2169 /* host is down, so answer for that node would be
2170 * DLM_LOCK_RES_OWNER_UNKNOWN. continue. */
2171 ret = 0;
2172 }
2173
2174 if (master != DLM_LOCK_RES_OWNER_UNKNOWN) {
2175 /* check to see if this master is in the recovery map */
2176 spin_lock(&dlm->spinlock);
2177 if (test_bit(master, dlm->recovery_map)) {
2178 mlog(ML_NOTICE, "%s: node %u has not seen "
2179 "node %u go down yet, and thinks the "
2180 "dead node is mastering the recovery "
2181 "lock. must wait.\n", dlm->name,
2182 nodenum, master);
2183 ret = -EAGAIN;
2184 }
2185 spin_unlock(&dlm->spinlock);
2186 mlog(0, "%s: reco lock master is %u\n", dlm->name,
2187 master);
2188 break;
2189 }
2190 }
2191 return ret;
2192 }
2193
2194 /*
2195 * DLM_DEREF_LOCKRES_MSG
2196 */
2197
2198 int dlm_drop_lockres_ref(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
2199 {
2200 struct dlm_deref_lockres deref;
2201 int ret = 0, r;
2202 const char *lockname;
2203 unsigned int namelen;
2204
2205 lockname = res->lockname.name;
2206 namelen = res->lockname.len;
2207 BUG_ON(namelen > O2NM_MAX_NAME_LEN);
2208
2209 memset(&deref, 0, sizeof(deref));
2210 deref.node_idx = dlm->node_num;
2211 deref.namelen = namelen;
2212 memcpy(deref.name, lockname, namelen);
2213
2214 ret = o2net_send_message(DLM_DEREF_LOCKRES_MSG, dlm->key,
2215 &deref, sizeof(deref), res->owner, &r);
2216 if (ret < 0)
2217 mlog(ML_ERROR, "%s: res %.*s, error %d send DEREF to node %u\n",
2218 dlm->name, namelen, lockname, ret, res->owner);
2219 else if (r < 0) {
2220 /* BAD. other node says I did not have a ref. */
2221 mlog(ML_ERROR, "%s: res %.*s, DEREF to node %u got %d\n",
2222 dlm->name, namelen, lockname, res->owner, r);
2223 dlm_print_one_lock_resource(res);
2224 BUG();
2225 }
2226 return ret;
2227 }
2228
2229 int dlm_deref_lockres_handler(struct o2net_msg *msg, u32 len, void *data,
2230 void **ret_data)
2231 {
2232 struct dlm_ctxt *dlm = data;
2233 struct dlm_deref_lockres *deref = (struct dlm_deref_lockres *)msg->buf;
2234 struct dlm_lock_resource *res = NULL;
2235 char *name;
2236 unsigned int namelen;
2237 int ret = -EINVAL;
2238 u8 node;
2239 unsigned int hash;
2240 struct dlm_work_item *item;
2241 int cleared = 0;
2242 int dispatch = 0;
2243
2244 if (!dlm_grab(dlm))
2245 return 0;
2246
2247 name = deref->name;
2248 namelen = deref->namelen;
2249 node = deref->node_idx;
2250
2251 if (namelen > DLM_LOCKID_NAME_MAX) {
2252 mlog(ML_ERROR, "Invalid name length!");
2253 goto done;
2254 }
2255 if (deref->node_idx >= O2NM_MAX_NODES) {
2256 mlog(ML_ERROR, "Invalid node number: %u\n", node);
2257 goto done;
2258 }
2259
2260 hash = dlm_lockid_hash(name, namelen);
2261
2262 spin_lock(&dlm->spinlock);
2263 res = __dlm_lookup_lockres_full(dlm, name, namelen, hash);
2264 if (!res) {
2265 spin_unlock(&dlm->spinlock);
2266 mlog(ML_ERROR, "%s:%.*s: bad lockres name\n",
2267 dlm->name, namelen, name);
2268 goto done;
2269 }
2270 spin_unlock(&dlm->spinlock);
2271
2272 spin_lock(&res->spinlock);
2273 if (res->state & DLM_LOCK_RES_SETREF_INPROG)
2274 dispatch = 1;
2275 else {
2276 BUG_ON(res->state & DLM_LOCK_RES_DROPPING_REF);
2277 if (test_bit(node, res->refmap)) {
2278 dlm_lockres_clear_refmap_bit(dlm, res, node);
2279 cleared = 1;
2280 }
2281 }
2282 spin_unlock(&res->spinlock);
2283
2284 if (!dispatch) {
2285 if (cleared)
2286 dlm_lockres_calc_usage(dlm, res);
2287 else {
2288 mlog(ML_ERROR, "%s:%.*s: node %u trying to drop ref "
2289 "but it is already dropped!\n", dlm->name,
2290 res->lockname.len, res->lockname.name, node);
2291 dlm_print_one_lock_resource(res);
2292 }
2293 ret = 0;
2294 goto done;
2295 }
2296
2297 item = kzalloc(sizeof(*item), GFP_NOFS);
2298 if (!item) {
2299 ret = -ENOMEM;
2300 mlog_errno(ret);
2301 goto done;
2302 }
2303
2304 dlm_init_work_item(dlm, item, dlm_deref_lockres_worker, NULL);
2305 item->u.dl.deref_res = res;
2306 item->u.dl.deref_node = node;
2307
2308 spin_lock(&dlm->work_lock);
2309 list_add_tail(&item->list, &dlm->work_list);
2310 spin_unlock(&dlm->work_lock);
2311
2312 queue_work(dlm->dlm_worker, &dlm->dispatched_work);
2313 return 0;
2314
2315 done:
2316 if (res)
2317 dlm_lockres_put(res);
2318 dlm_put(dlm);
2319
2320 return ret;
2321 }
2322
2323 static void dlm_deref_lockres_worker(struct dlm_work_item *item, void *data)
2324 {
2325 struct dlm_ctxt *dlm;
2326 struct dlm_lock_resource *res;
2327 u8 node;
2328 u8 cleared = 0;
2329
2330 dlm = item->dlm;
2331 res = item->u.dl.deref_res;
2332 node = item->u.dl.deref_node;
2333
2334 spin_lock(&res->spinlock);
2335 BUG_ON(res->state & DLM_LOCK_RES_DROPPING_REF);
2336 if (test_bit(node, res->refmap)) {
2337 __dlm_wait_on_lockres_flags(res, DLM_LOCK_RES_SETREF_INPROG);
2338 dlm_lockres_clear_refmap_bit(dlm, res, node);
2339 cleared = 1;
2340 }
2341 spin_unlock(&res->spinlock);
2342
2343 if (cleared) {
2344 mlog(0, "%s:%.*s node %u ref dropped in dispatch\n",
2345 dlm->name, res->lockname.len, res->lockname.name, node);
2346 dlm_lockres_calc_usage(dlm, res);
2347 } else {
2348 mlog(ML_ERROR, "%s:%.*s: node %u trying to drop ref "
2349 "but it is already dropped!\n", dlm->name,
2350 res->lockname.len, res->lockname.name, node);
2351 dlm_print_one_lock_resource(res);
2352 }
2353
2354 dlm_lockres_put(res);
2355 }
2356
2357 /*
2358 * A migrateable resource is one that is :
2359 * 1. locally mastered, and,
2360 * 2. zero local locks, and,
2361 * 3. one or more non-local locks, or, one or more references
2362 * Returns 1 if yes, 0 if not.
2363 */
2364 static int dlm_is_lockres_migrateable(struct dlm_ctxt *dlm,
2365 struct dlm_lock_resource *res)
2366 {
2367 enum dlm_lockres_list idx;
2368 int nonlocal = 0, node_ref;
2369 struct list_head *queue;
2370 struct dlm_lock *lock;
2371 u64 cookie;
2372
2373 assert_spin_locked(&res->spinlock);
2374
2375 if (res->owner != dlm->node_num)
2376 return 0;
2377
2378 for (idx = DLM_GRANTED_LIST; idx <= DLM_BLOCKED_LIST; idx++) {
2379 queue = dlm_list_idx_to_ptr(res, idx);
2380 list_for_each_entry(lock, queue, list) {
2381 if (lock->ml.node != dlm->node_num) {
2382 nonlocal++;
2383 continue;
2384 }
2385 cookie = be64_to_cpu(lock->ml.cookie);
2386 mlog(0, "%s: Not migrateable res %.*s, lock %u:%llu on "
2387 "%s list\n", dlm->name, res->lockname.len,
2388 res->lockname.name,
2389 dlm_get_lock_cookie_node(cookie),
2390 dlm_get_lock_cookie_seq(cookie),
2391 dlm_list_in_text(idx));
2392 return 0;
2393 }
2394 }
2395
2396 if (!nonlocal) {
2397 node_ref = find_next_bit(res->refmap, O2NM_MAX_NODES, 0);
2398 if (node_ref >= O2NM_MAX_NODES)
2399 return 0;
2400 }
2401
2402 mlog(0, "%s: res %.*s, Migrateable\n", dlm->name, res->lockname.len,
2403 res->lockname.name);
2404
2405 return 1;
2406 }
2407
2408 /*
2409 * DLM_MIGRATE_LOCKRES
2410 */
2411
2412
2413 static int dlm_migrate_lockres(struct dlm_ctxt *dlm,
2414 struct dlm_lock_resource *res, u8 target)
2415 {
2416 struct dlm_master_list_entry *mle = NULL;
2417 struct dlm_master_list_entry *oldmle = NULL;
2418 struct dlm_migratable_lockres *mres = NULL;
2419 int ret = 0;
2420 const char *name;
2421 unsigned int namelen;
2422 int mle_added = 0;
2423 int wake = 0;
2424
2425 if (!dlm_grab(dlm))
2426 return -EINVAL;
2427
2428 BUG_ON(target == O2NM_MAX_NODES);
2429
2430 name = res->lockname.name;
2431 namelen = res->lockname.len;
2432
2433 mlog(0, "%s: Migrating %.*s to node %u\n", dlm->name, namelen, name,
2434 target);
2435
2436 /* preallocate up front. if this fails, abort */
2437 ret = -ENOMEM;
2438 mres = (struct dlm_migratable_lockres *) __get_free_page(GFP_NOFS);
2439 if (!mres) {
2440 mlog_errno(ret);
2441 goto leave;
2442 }
2443
2444 mle = kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
2445 if (!mle) {
2446 mlog_errno(ret);
2447 goto leave;
2448 }
2449 ret = 0;
2450
2451 /*
2452 * clear any existing master requests and
2453 * add the migration mle to the list
2454 */
2455 spin_lock(&dlm->spinlock);
2456 spin_lock(&dlm->master_lock);
2457 ret = dlm_add_migration_mle(dlm, res, mle, &oldmle, name,
2458 namelen, target, dlm->node_num);
2459 /* get an extra reference on the mle.
2460 * otherwise the assert_master from the new
2461 * master will destroy this.
2462 */
2463 dlm_get_mle_inuse(mle);
2464 spin_unlock(&dlm->master_lock);
2465 spin_unlock(&dlm->spinlock);
2466
2467 if (ret == -EEXIST) {
2468 mlog(0, "another process is already migrating it\n");
2469 goto fail;
2470 }
2471 mle_added = 1;
2472
2473 /*
2474 * set the MIGRATING flag and flush asts
2475 * if we fail after this we need to re-dirty the lockres
2476 */
2477 if (dlm_mark_lockres_migrating(dlm, res, target) < 0) {
2478 mlog(ML_ERROR, "tried to migrate %.*s to %u, but "
2479 "the target went down.\n", res->lockname.len,
2480 res->lockname.name, target);
2481 spin_lock(&res->spinlock);
2482 res->state &= ~DLM_LOCK_RES_MIGRATING;
2483 wake = 1;
2484 spin_unlock(&res->spinlock);
2485 ret = -EINVAL;
2486 }
2487
2488 fail:
2489 if (oldmle) {
2490 /* master is known, detach if not already detached */
2491 dlm_mle_detach_hb_events(dlm, oldmle);
2492 dlm_put_mle(oldmle);
2493 }
2494
2495 if (ret < 0) {
2496 if (mle_added) {
2497 dlm_mle_detach_hb_events(dlm, mle);
2498 dlm_put_mle(mle);
2499 dlm_put_mle_inuse(mle);
2500 } else if (mle) {
2501 kmem_cache_free(dlm_mle_cache, mle);
2502 mle = NULL;
2503 }
2504 goto leave;
2505 }
2506
2507 /*
2508 * at this point, we have a migration target, an mle
2509 * in the master list, and the MIGRATING flag set on
2510 * the lockres
2511 */
2512
2513 /* now that remote nodes are spinning on the MIGRATING flag,
2514 * ensure that all assert_master work is flushed. */
2515 flush_workqueue(dlm->dlm_worker);
2516
2517 /* notify new node and send all lock state */
2518 /* call send_one_lockres with migration flag.
2519 * this serves as notice to the target node that a
2520 * migration is starting. */
2521 ret = dlm_send_one_lockres(dlm, res, mres, target,
2522 DLM_MRES_MIGRATION);
2523
2524 if (ret < 0) {
2525 mlog(0, "migration to node %u failed with %d\n",
2526 target, ret);
2527 /* migration failed, detach and clean up mle */
2528 dlm_mle_detach_hb_events(dlm, mle);
2529 dlm_put_mle(mle);
2530 dlm_put_mle_inuse(mle);
2531 spin_lock(&res->spinlock);
2532 res->state &= ~DLM_LOCK_RES_MIGRATING;
2533 wake = 1;
2534 spin_unlock(&res->spinlock);
2535 if (dlm_is_host_down(ret))
2536 dlm_wait_for_node_death(dlm, target,
2537 DLM_NODE_DEATH_WAIT_MAX);
2538 goto leave;
2539 }
2540
2541 /* at this point, the target sends a message to all nodes,
2542 * (using dlm_do_migrate_request). this node is skipped since
2543 * we had to put an mle in the list to begin the process. this
2544 * node now waits for target to do an assert master. this node
2545 * will be the last one notified, ensuring that the migration
2546 * is complete everywhere. if the target dies while this is
2547 * going on, some nodes could potentially see the target as the
2548 * master, so it is important that my recovery finds the migration
2549 * mle and sets the master to UNKNOWN. */
2550
2551
2552 /* wait for new node to assert master */
2553 while (1) {
2554 ret = wait_event_interruptible_timeout(mle->wq,
2555 (atomic_read(&mle->woken) == 1),
2556 msecs_to_jiffies(5000));
2557
2558 if (ret >= 0) {
2559 if (atomic_read(&mle->woken) == 1 ||
2560 res->owner == target)
2561 break;
2562
2563 mlog(0, "%s:%.*s: timed out during migration\n",
2564 dlm->name, res->lockname.len, res->lockname.name);
2565 /* avoid hang during shutdown when migrating lockres
2566 * to a node which also goes down */
2567 if (dlm_is_node_dead(dlm, target)) {
2568 mlog(0, "%s:%.*s: expected migration "
2569 "target %u is no longer up, restarting\n",
2570 dlm->name, res->lockname.len,
2571 res->lockname.name, target);
2572 ret = -EINVAL;
2573 /* migration failed, detach and clean up mle */
2574 dlm_mle_detach_hb_events(dlm, mle);
2575 dlm_put_mle(mle);
2576 dlm_put_mle_inuse(mle);
2577 spin_lock(&res->spinlock);
2578 res->state &= ~DLM_LOCK_RES_MIGRATING;
2579 wake = 1;
2580 spin_unlock(&res->spinlock);
2581 goto leave;
2582 }
2583 } else
2584 mlog(0, "%s:%.*s: caught signal during migration\n",
2585 dlm->name, res->lockname.len, res->lockname.name);
2586 }
2587
2588 /* all done, set the owner, clear the flag */
2589 spin_lock(&res->spinlock);
2590 dlm_set_lockres_owner(dlm, res, target);
2591 res->state &= ~DLM_LOCK_RES_MIGRATING;
2592 dlm_remove_nonlocal_locks(dlm, res);
2593 spin_unlock(&res->spinlock);
2594 wake_up(&res->wq);
2595
2596 /* master is known, detach if not already detached */
2597 dlm_mle_detach_hb_events(dlm, mle);
2598 dlm_put_mle_inuse(mle);
2599 ret = 0;
2600
2601 dlm_lockres_calc_usage(dlm, res);
2602
2603 leave:
2604 /* re-dirty the lockres if we failed */
2605 if (ret < 0)
2606 dlm_kick_thread(dlm, res);
2607
2608 /* wake up waiters if the MIGRATING flag got set
2609 * but migration failed */
2610 if (wake)
2611 wake_up(&res->wq);
2612
2613 if (mres)
2614 free_page((unsigned long)mres);
2615
2616 dlm_put(dlm);
2617
2618 mlog(0, "%s: Migrating %.*s to %u, returns %d\n", dlm->name, namelen,
2619 name, target, ret);
2620 return ret;
2621 }
2622
2623 #define DLM_MIGRATION_RETRY_MS 100
2624
2625 /*
2626 * Should be called only after beginning the domain leave process.
2627 * There should not be any remaining locks on nonlocal lock resources,
2628 * and there should be no local locks left on locally mastered resources.
2629 *
2630 * Called with the dlm spinlock held, may drop it to do migration, but
2631 * will re-acquire before exit.
2632 *
2633 * Returns: 1 if dlm->spinlock was dropped/retaken, 0 if never dropped
2634 */
2635 int dlm_empty_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
2636 {
2637 int ret;
2638 int lock_dropped = 0;
2639 u8 target = O2NM_MAX_NODES;
2640
2641 assert_spin_locked(&dlm->spinlock);
2642
2643 spin_lock(&res->spinlock);
2644 if (dlm_is_lockres_migrateable(dlm, res))
2645 target = dlm_pick_migration_target(dlm, res);
2646 spin_unlock(&res->spinlock);
2647
2648 if (target == O2NM_MAX_NODES)
2649 goto leave;
2650
2651 /* Wheee! Migrate lockres here! Will sleep so drop spinlock. */
2652 spin_unlock(&dlm->spinlock);
2653 lock_dropped = 1;
2654 ret = dlm_migrate_lockres(dlm, res, target);
2655 if (ret)
2656 mlog(0, "%s: res %.*s, Migrate to node %u failed with %d\n",
2657 dlm->name, res->lockname.len, res->lockname.name,
2658 target, ret);
2659 spin_lock(&dlm->spinlock);
2660 leave:
2661 return lock_dropped;
2662 }
2663
2664 int dlm_lock_basts_flushed(struct dlm_ctxt *dlm, struct dlm_lock *lock)
2665 {
2666 int ret;
2667 spin_lock(&dlm->ast_lock);
2668 spin_lock(&lock->spinlock);
2669 ret = (list_empty(&lock->bast_list) && !lock->bast_pending);
2670 spin_unlock(&lock->spinlock);
2671 spin_unlock(&dlm->ast_lock);
2672 return ret;
2673 }
2674
2675 static int dlm_migration_can_proceed(struct dlm_ctxt *dlm,
2676 struct dlm_lock_resource *res,
2677 u8 mig_target)
2678 {
2679 int can_proceed;
2680 spin_lock(&res->spinlock);
2681 can_proceed = !!(res->state & DLM_LOCK_RES_MIGRATING);
2682 spin_unlock(&res->spinlock);
2683
2684 /* target has died, so make the caller break out of the
2685 * wait_event, but caller must recheck the domain_map */
2686 spin_lock(&dlm->spinlock);
2687 if (!test_bit(mig_target, dlm->domain_map))
2688 can_proceed = 1;
2689 spin_unlock(&dlm->spinlock);
2690 return can_proceed;
2691 }
2692
2693 static int dlm_lockres_is_dirty(struct dlm_ctxt *dlm,
2694 struct dlm_lock_resource *res)
2695 {
2696 int ret;
2697 spin_lock(&res->spinlock);
2698 ret = !!(res->state & DLM_LOCK_RES_DIRTY);
2699 spin_unlock(&res->spinlock);
2700 return ret;
2701 }
2702
2703
2704 static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
2705 struct dlm_lock_resource *res,
2706 u8 target)
2707 {
2708 int ret = 0;
2709
2710 mlog(0, "dlm_mark_lockres_migrating: %.*s, from %u to %u\n",
2711 res->lockname.len, res->lockname.name, dlm->node_num,
2712 target);
2713 /* need to set MIGRATING flag on lockres. this is done by
2714 * ensuring that all asts have been flushed for this lockres. */
2715 spin_lock(&res->spinlock);
2716 BUG_ON(res->migration_pending);
2717 res->migration_pending = 1;
2718 /* strategy is to reserve an extra ast then release
2719 * it below, letting the release do all of the work */
2720 __dlm_lockres_reserve_ast(res);
2721 spin_unlock(&res->spinlock);
2722
2723 /* now flush all the pending asts */
2724 dlm_kick_thread(dlm, res);
2725 /* before waiting on DIRTY, block processes which may
2726 * try to dirty the lockres before MIGRATING is set */
2727 spin_lock(&res->spinlock);
2728 BUG_ON(res->state & DLM_LOCK_RES_BLOCK_DIRTY);
2729 res->state |= DLM_LOCK_RES_BLOCK_DIRTY;
2730 spin_unlock(&res->spinlock);
2731 /* now wait on any pending asts and the DIRTY state */
2732 wait_event(dlm->ast_wq, !dlm_lockres_is_dirty(dlm, res));
2733 dlm_lockres_release_ast(dlm, res);
2734
2735 mlog(0, "about to wait on migration_wq, dirty=%s\n",
2736 res->state & DLM_LOCK_RES_DIRTY ? "yes" : "no");
2737 /* if the extra ref we just put was the final one, this
2738 * will pass thru immediately. otherwise, we need to wait
2739 * for the last ast to finish. */
2740 again:
2741 ret = wait_event_interruptible_timeout(dlm->migration_wq,
2742 dlm_migration_can_proceed(dlm, res, target),
2743 msecs_to_jiffies(1000));
2744 if (ret < 0) {
2745 mlog(0, "woken again: migrating? %s, dead? %s\n",
2746 res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
2747 test_bit(target, dlm->domain_map) ? "no":"yes");
2748 } else {
2749 mlog(0, "all is well: migrating? %s, dead? %s\n",
2750 res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
2751 test_bit(target, dlm->domain_map) ? "no":"yes");
2752 }
2753 if (!dlm_migration_can_proceed(dlm, res, target)) {
2754 mlog(0, "trying again...\n");
2755 goto again;
2756 }
2757
2758 ret = 0;
2759 /* did the target go down or die? */
2760 spin_lock(&dlm->spinlock);
2761 if (!test_bit(target, dlm->domain_map)) {
2762 mlog(ML_ERROR, "aha. migration target %u just went down\n",
2763 target);
2764 ret = -EHOSTDOWN;
2765 }
2766 spin_unlock(&dlm->spinlock);
2767
2768 /*
2769 * if target is down, we need to clear DLM_LOCK_RES_BLOCK_DIRTY for
2770 * another try; otherwise, we are sure the MIGRATING state is there,
2771 * drop the unneded state which blocked threads trying to DIRTY
2772 */
2773 spin_lock(&res->spinlock);
2774 BUG_ON(!(res->state & DLM_LOCK_RES_BLOCK_DIRTY));
2775 res->state &= ~DLM_LOCK_RES_BLOCK_DIRTY;
2776 if (!ret)
2777 BUG_ON(!(res->state & DLM_LOCK_RES_MIGRATING));
2778 spin_unlock(&res->spinlock);
2779
2780 /*
2781 * at this point:
2782 *
2783 * o the DLM_LOCK_RES_MIGRATING flag is set if target not down
2784 * o there are no pending asts on this lockres
2785 * o all processes trying to reserve an ast on this
2786 * lockres must wait for the MIGRATING flag to clear
2787 */
2788 return ret;
2789 }
2790
2791 /* last step in the migration process.
2792 * original master calls this to free all of the dlm_lock
2793 * structures that used to be for other nodes. */
2794 static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
2795 struct dlm_lock_resource *res)
2796 {
2797 struct list_head *queue = &res->granted;
2798 int i, bit;
2799 struct dlm_lock *lock, *next;
2800
2801 assert_spin_locked(&res->spinlock);
2802
2803 BUG_ON(res->owner == dlm->node_num);
2804
2805 for (i=0; i<3; i++) {
2806 list_for_each_entry_safe(lock, next, queue, list) {
2807 if (lock->ml.node != dlm->node_num) {
2808 mlog(0, "putting lock for node %u\n",
2809 lock->ml.node);
2810 /* be extra careful */
2811 BUG_ON(!list_empty(&lock->ast_list));
2812 BUG_ON(!list_empty(&lock->bast_list));
2813 BUG_ON(lock->ast_pending);
2814 BUG_ON(lock->bast_pending);
2815 dlm_lockres_clear_refmap_bit(dlm, res,
2816 lock->ml.node);
2817 list_del_init(&lock->list);
2818 dlm_lock_put(lock);
2819 /* In a normal unlock, we would have added a
2820 * DLM_UNLOCK_FREE_LOCK action. Force it. */
2821 dlm_lock_put(lock);
2822 }
2823 }
2824 queue++;
2825 }
2826 bit = 0;
2827 while (1) {
2828 bit = find_next_bit(res->refmap, O2NM_MAX_NODES, bit);
2829 if (bit >= O2NM_MAX_NODES)
2830 break;
2831 /* do not clear the local node reference, if there is a
2832 * process holding this, let it drop the ref itself */
2833 if (bit != dlm->node_num) {
2834 mlog(0, "%s:%.*s: node %u had a ref to this "
2835 "migrating lockres, clearing\n", dlm->name,
2836 res->lockname.len, res->lockname.name, bit);
2837 dlm_lockres_clear_refmap_bit(dlm, res, bit);
2838 }
2839 bit++;
2840 }
2841 }
2842
2843 /*
2844 * Pick a node to migrate the lock resource to. This function selects a
2845 * potential target based first on the locks and then on refmap. It skips
2846 * nodes that are in the process of exiting the domain.
2847 */
2848 static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
2849 struct dlm_lock_resource *res)
2850 {
2851 enum dlm_lockres_list idx;
2852 struct list_head *queue = &res->granted;
2853 struct dlm_lock *lock;
2854 int noderef;
2855 u8 nodenum = O2NM_MAX_NODES;
2856
2857 assert_spin_locked(&dlm->spinlock);
2858 assert_spin_locked(&res->spinlock);
2859
2860 /* Go through all the locks */
2861 for (idx = DLM_GRANTED_LIST; idx <= DLM_BLOCKED_LIST; idx++) {
2862 queue = dlm_list_idx_to_ptr(res, idx);
2863 list_for_each_entry(lock, queue, list) {
2864 if (lock->ml.node == dlm->node_num)
2865 continue;
2866 if (test_bit(lock->ml.node, dlm->exit_domain_map))
2867 continue;
2868 nodenum = lock->ml.node;
2869 goto bail;
2870 }
2871 }
2872
2873 /* Go thru the refmap */
2874 noderef = -1;
2875 while (1) {
2876 noderef = find_next_bit(res->refmap, O2NM_MAX_NODES,
2877 noderef + 1);
2878 if (noderef >= O2NM_MAX_NODES)
2879 break;
2880 if (noderef == dlm->node_num)
2881 continue;
2882 if (test_bit(noderef, dlm->exit_domain_map))
2883 continue;
2884 nodenum = noderef;
2885 goto bail;
2886 }
2887
2888 bail:
2889 return nodenum;
2890 }
2891
2892 /* this is called by the new master once all lockres
2893 * data has been received */
2894 static int dlm_do_migrate_request(struct dlm_ctxt *dlm,
2895 struct dlm_lock_resource *res,
2896 u8 master, u8 new_master,
2897 struct dlm_node_iter *iter)
2898 {
2899 struct dlm_migrate_request migrate;
2900 int ret, skip, status = 0;
2901 int nodenum;
2902
2903 memset(&migrate, 0, sizeof(migrate));
2904 migrate.namelen = res->lockname.len;
2905 memcpy(migrate.name, res->lockname.name, migrate.namelen);
2906 migrate.new_master = new_master;
2907 migrate.master = master;
2908
2909 ret = 0;
2910
2911 /* send message to all nodes, except the master and myself */
2912 while ((nodenum = dlm_node_iter_next(iter)) >= 0) {
2913 if (nodenum == master ||
2914 nodenum == new_master)
2915 continue;
2916
2917 /* We could race exit domain. If exited, skip. */
2918 spin_lock(&dlm->spinlock);
2919 skip = (!test_bit(nodenum, dlm->domain_map));
2920 spin_unlock(&dlm->spinlock);
2921 if (skip) {
2922 clear_bit(nodenum, iter->node_map);
2923 continue;
2924 }
2925
2926 ret = o2net_send_message(DLM_MIGRATE_REQUEST_MSG, dlm->key,
2927 &migrate, sizeof(migrate), nodenum,
2928 &status);
2929 if (ret < 0) {
2930 mlog(ML_ERROR, "%s: res %.*s, Error %d send "
2931 "MIGRATE_REQUEST to node %u\n", dlm->name,
2932 migrate.namelen, migrate.name, ret, nodenum);
2933 if (!dlm_is_host_down(ret)) {
2934 mlog(ML_ERROR, "unhandled error=%d!\n", ret);
2935 BUG();
2936 }
2937 clear_bit(nodenum, iter->node_map);
2938 ret = 0;
2939 } else if (status < 0) {
2940 mlog(0, "migrate request (node %u) returned %d!\n",
2941 nodenum, status);
2942 ret = status;
2943 } else if (status == DLM_MIGRATE_RESPONSE_MASTERY_REF) {
2944 /* during the migration request we short-circuited
2945 * the mastery of the lockres. make sure we have
2946 * a mastery ref for nodenum */
2947 mlog(0, "%s:%.*s: need ref for node %u\n",
2948 dlm->name, res->lockname.len, res->lockname.name,
2949 nodenum);
2950 spin_lock(&res->spinlock);
2951 dlm_lockres_set_refmap_bit(dlm, res, nodenum);
2952 spin_unlock(&res->spinlock);
2953 }
2954 }
2955
2956 if (ret < 0)
2957 mlog_errno(ret);
2958
2959 mlog(0, "returning ret=%d\n", ret);
2960 return ret;
2961 }
2962
2963
2964 /* if there is an existing mle for this lockres, we now know who the master is.
2965 * (the one who sent us *this* message) we can clear it up right away.
2966 * since the process that put the mle on the list still has a reference to it,
2967 * we can unhash it now, set the master and wake the process. as a result,
2968 * we will have no mle in the list to start with. now we can add an mle for
2969 * the migration and this should be the only one found for those scanning the
2970 * list. */
2971 int dlm_migrate_request_handler(struct o2net_msg *msg, u32 len, void *data,
2972 void **ret_data)
2973 {
2974 struct dlm_ctxt *dlm = data;
2975 struct dlm_lock_resource *res = NULL;
2976 struct dlm_migrate_request *migrate = (struct dlm_migrate_request *) msg->buf;
2977 struct dlm_master_list_entry *mle = NULL, *oldmle = NULL;
2978 const char *name;
2979 unsigned int namelen, hash;
2980 int ret = 0;
2981
2982 if (!dlm_grab(dlm))
2983 return -EINVAL;
2984
2985 name = migrate->name;
2986 namelen = migrate->namelen;
2987 hash = dlm_lockid_hash(name, namelen);
2988
2989 /* preallocate.. if this fails, abort */
2990 mle = kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
2991
2992 if (!mle) {
2993 ret = -ENOMEM;
2994 goto leave;
2995 }
2996
2997 /* check for pre-existing lock */
2998 spin_lock(&dlm->spinlock);
2999 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
3000 if (res) {
3001 spin_lock(&res->spinlock);
3002 if (res->state & DLM_LOCK_RES_RECOVERING) {
3003 /* if all is working ok, this can only mean that we got
3004 * a migrate request from a node that we now see as
3005 * dead. what can we do here? drop it to the floor? */
3006 spin_unlock(&res->spinlock);
3007 mlog(ML_ERROR, "Got a migrate request, but the "
3008 "lockres is marked as recovering!");
3009 kmem_cache_free(dlm_mle_cache, mle);
3010 ret = -EINVAL; /* need a better solution */
3011 goto unlock;
3012 }
3013 res->state |= DLM_LOCK_RES_MIGRATING;
3014 spin_unlock(&res->spinlock);
3015 }
3016
3017 spin_lock(&dlm->master_lock);
3018 /* ignore status. only nonzero status would BUG. */
3019 ret = dlm_add_migration_mle(dlm, res, mle, &oldmle,
3020 name, namelen,
3021 migrate->new_master,
3022 migrate->master);
3023
3024 spin_unlock(&dlm->master_lock);
3025 unlock:
3026 spin_unlock(&dlm->spinlock);
3027
3028 if (oldmle) {
3029 /* master is known, detach if not already detached */
3030 dlm_mle_detach_hb_events(dlm, oldmle);
3031 dlm_put_mle(oldmle);
3032 }
3033
3034 if (res)
3035 dlm_lockres_put(res);
3036 leave:
3037 dlm_put(dlm);
3038 return ret;
3039 }
3040
3041 /* must be holding dlm->spinlock and dlm->master_lock
3042 * when adding a migration mle, we can clear any other mles
3043 * in the master list because we know with certainty that
3044 * the master is "master". so we remove any old mle from
3045 * the list after setting it's master field, and then add
3046 * the new migration mle. this way we can hold with the rule
3047 * of having only one mle for a given lock name at all times. */
3048 static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
3049 struct dlm_lock_resource *res,
3050 struct dlm_master_list_entry *mle,
3051 struct dlm_master_list_entry **oldmle,
3052 const char *name, unsigned int namelen,
3053 u8 new_master, u8 master)
3054 {
3055 int found;
3056 int ret = 0;
3057
3058 *oldmle = NULL;
3059
3060 assert_spin_locked(&dlm->spinlock);
3061 assert_spin_locked(&dlm->master_lock);
3062
3063 /* caller is responsible for any ref taken here on oldmle */
3064 found = dlm_find_mle(dlm, oldmle, (char *)name, namelen);
3065 if (found) {
3066 struct dlm_master_list_entry *tmp = *oldmle;
3067 spin_lock(&tmp->spinlock);
3068 if (tmp->type == DLM_MLE_MIGRATION) {
3069 if (master == dlm->node_num) {
3070 /* ah another process raced me to it */
3071 mlog(0, "tried to migrate %.*s, but some "
3072 "process beat me to it\n",
3073 namelen, name);
3074 ret = -EEXIST;
3075 } else {
3076 /* bad. 2 NODES are trying to migrate! */
3077 mlog(ML_ERROR, "migration error mle: "
3078 "master=%u new_master=%u // request: "
3079 "master=%u new_master=%u // "
3080 "lockres=%.*s\n",
3081 tmp->master, tmp->new_master,
3082 master, new_master,
3083 namelen, name);
3084 BUG();
3085 }
3086 } else {
3087 /* this is essentially what assert_master does */
3088 tmp->master = master;
3089 atomic_set(&tmp->woken, 1);
3090 wake_up(&tmp->wq);
3091 /* remove it so that only one mle will be found */
3092 __dlm_unlink_mle(dlm, tmp);
3093 __dlm_mle_detach_hb_events(dlm, tmp);
3094 ret = DLM_MIGRATE_RESPONSE_MASTERY_REF;
3095 mlog(0, "%s:%.*s: master=%u, newmaster=%u, "
3096 "telling master to get ref for cleared out mle "
3097 "during migration\n", dlm->name, namelen, name,
3098 master, new_master);
3099 }
3100 spin_unlock(&tmp->spinlock);
3101 }
3102
3103 /* now add a migration mle to the tail of the list */
3104 dlm_init_mle(mle, DLM_MLE_MIGRATION, dlm, res, name, namelen);
3105 mle->new_master = new_master;
3106 /* the new master will be sending an assert master for this.
3107 * at that point we will get the refmap reference */
3108 mle->master = master;
3109 /* do this for consistency with other mle types */
3110 set_bit(new_master, mle->maybe_map);
3111 __dlm_insert_mle(dlm, mle);
3112
3113 return ret;
3114 }
3115
3116 /*
3117 * Sets the owner of the lockres, associated to the mle, to UNKNOWN
3118 */
3119 static struct dlm_lock_resource *dlm_reset_mleres_owner(struct dlm_ctxt *dlm,
3120 struct dlm_master_list_entry *mle)
3121 {
3122 struct dlm_lock_resource *res;
3123
3124 /* Find the lockres associated to the mle and set its owner to UNK */
3125 res = __dlm_lookup_lockres(dlm, mle->mname, mle->mnamelen,
3126 mle->mnamehash);
3127 if (res) {
3128 spin_unlock(&dlm->master_lock);
3129
3130 /* move lockres onto recovery list */
3131 spin_lock(&res->spinlock);
3132 dlm_set_lockres_owner(dlm, res, DLM_LOCK_RES_OWNER_UNKNOWN);
3133 dlm_move_lockres_to_recovery_list(dlm, res);
3134 spin_unlock(&res->spinlock);
3135 dlm_lockres_put(res);
3136
3137 /* about to get rid of mle, detach from heartbeat */
3138 __dlm_mle_detach_hb_events(dlm, mle);
3139
3140 /* dump the mle */
3141 spin_lock(&dlm->master_lock);
3142 __dlm_put_mle(mle);
3143 spin_unlock(&dlm->master_lock);
3144 }
3145
3146 return res;
3147 }
3148
3149 static void dlm_clean_migration_mle(struct dlm_ctxt *dlm,
3150 struct dlm_master_list_entry *mle)
3151 {
3152 __dlm_mle_detach_hb_events(dlm, mle);
3153
3154 spin_lock(&mle->spinlock);
3155 __dlm_unlink_mle(dlm, mle);
3156 atomic_set(&mle->woken, 1);
3157 spin_unlock(&mle->spinlock);
3158
3159 wake_up(&mle->wq);
3160 }
3161
3162 static void dlm_clean_block_mle(struct dlm_ctxt *dlm,
3163 struct dlm_master_list_entry *mle, u8 dead_node)
3164 {
3165 int bit;
3166
3167 BUG_ON(mle->type != DLM_MLE_BLOCK);
3168
3169 spin_lock(&mle->spinlock);
3170 bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
3171 if (bit != dead_node) {
3172 mlog(0, "mle found, but dead node %u would not have been "
3173 "master\n", dead_node);
3174 spin_unlock(&mle->spinlock);
3175 } else {
3176 /* Must drop the refcount by one since the assert_master will
3177 * never arrive. This may result in the mle being unlinked and
3178 * freed, but there may still be a process waiting in the
3179 * dlmlock path which is fine. */
3180 mlog(0, "node %u was expected master\n", dead_node);
3181 atomic_set(&mle->woken, 1);
3182 spin_unlock(&mle->spinlock);
3183 wake_up(&mle->wq);
3184
3185 /* Do not need events any longer, so detach from heartbeat */
3186 __dlm_mle_detach_hb_events(dlm, mle);
3187 __dlm_put_mle(mle);
3188 }
3189 }
3190
3191 void dlm_clean_master_list(struct dlm_ctxt *dlm, u8 dead_node)
3192 {
3193 struct dlm_master_list_entry *mle;
3194 struct dlm_lock_resource *res;
3195 struct hlist_head *bucket;
3196 struct hlist_node *list;
3197 unsigned int i;
3198
3199 mlog(0, "dlm=%s, dead node=%u\n", dlm->name, dead_node);
3200 top:
3201 assert_spin_locked(&dlm->spinlock);
3202
3203 /* clean the master list */
3204 spin_lock(&dlm->master_lock);
3205 for (i = 0; i < DLM_HASH_BUCKETS; i++) {
3206 bucket = dlm_master_hash(dlm, i);
3207 hlist_for_each(list, bucket) {
3208 mle = hlist_entry(list, struct dlm_master_list_entry,
3209 master_hash_node);
3210
3211 BUG_ON(mle->type != DLM_MLE_BLOCK &&
3212 mle->type != DLM_MLE_MASTER &&
3213 mle->type != DLM_MLE_MIGRATION);
3214
3215 /* MASTER mles are initiated locally. The waiting
3216 * process will notice the node map change shortly.
3217 * Let that happen as normal. */
3218 if (mle->type == DLM_MLE_MASTER)
3219 continue;
3220
3221 /* BLOCK mles are initiated by other nodes. Need to
3222 * clean up if the dead node would have been the
3223 * master. */
3224 if (mle->type == DLM_MLE_BLOCK) {
3225 dlm_clean_block_mle(dlm, mle, dead_node);
3226 continue;
3227 }
3228
3229 /* Everything else is a MIGRATION mle */
3230
3231 /* The rule for MIGRATION mles is that the master
3232 * becomes UNKNOWN if *either* the original or the new
3233 * master dies. All UNKNOWN lockres' are sent to
3234 * whichever node becomes the recovery master. The new
3235 * master is responsible for determining if there is
3236 * still a master for this lockres, or if he needs to
3237 * take over mastery. Either way, this node should
3238 * expect another message to resolve this. */
3239
3240 if (mle->master != dead_node &&
3241 mle->new_master != dead_node)
3242 continue;
3243
3244 if (mle->new_master == dead_node && mle->inuse) {
3245 mlog(ML_NOTICE, "%s: target %u died during "
3246 "migration from %u, the MLE is "
3247 "still keep used, ignore it!\n",
3248 dlm->name, dead_node,
3249 mle->master);
3250 continue;
3251 }
3252
3253 /* If we have reached this point, this mle needs to be
3254 * removed from the list and freed. */
3255 dlm_clean_migration_mle(dlm, mle);
3256
3257 mlog(0, "%s: node %u died during migration from "
3258 "%u to %u!\n", dlm->name, dead_node, mle->master,
3259 mle->new_master);
3260
3261 /* If we find a lockres associated with the mle, we've
3262 * hit this rare case that messes up our lock ordering.
3263 * If so, we need to drop the master lock so that we can
3264 * take the lockres lock, meaning that we will have to
3265 * restart from the head of list. */
3266 res = dlm_reset_mleres_owner(dlm, mle);
3267 if (res)
3268 /* restart */
3269 goto top;
3270
3271 /* This may be the last reference */
3272 __dlm_put_mle(mle);
3273 }
3274 }
3275 spin_unlock(&dlm->master_lock);
3276 }
3277
3278 int dlm_finish_migration(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
3279 u8 old_master)
3280 {
3281 struct dlm_node_iter iter;
3282 int ret = 0;
3283
3284 spin_lock(&dlm->spinlock);
3285 dlm_node_iter_init(dlm->domain_map, &iter);
3286 clear_bit(old_master, iter.node_map);
3287 clear_bit(dlm->node_num, iter.node_map);
3288 spin_unlock(&dlm->spinlock);
3289
3290 /* ownership of the lockres is changing. account for the
3291 * mastery reference here since old_master will briefly have
3292 * a reference after the migration completes */
3293 spin_lock(&res->spinlock);
3294 dlm_lockres_set_refmap_bit(dlm, res, old_master);
3295 spin_unlock(&res->spinlock);
3296
3297 mlog(0, "now time to do a migrate request to other nodes\n");
3298 ret = dlm_do_migrate_request(dlm, res, old_master,
3299 dlm->node_num, &iter);
3300 if (ret < 0) {
3301 mlog_errno(ret);
3302 goto leave;
3303 }
3304
3305 mlog(0, "doing assert master of %.*s to all except the original node\n",
3306 res->lockname.len, res->lockname.name);
3307 /* this call now finishes out the nodemap
3308 * even if one or more nodes die */
3309 ret = dlm_do_assert_master(dlm, res, iter.node_map,
3310 DLM_ASSERT_MASTER_FINISH_MIGRATION);
3311 if (ret < 0) {
3312 /* no longer need to retry. all living nodes contacted. */
3313 mlog_errno(ret);
3314 ret = 0;
3315 }
3316
3317 memset(iter.node_map, 0, sizeof(iter.node_map));
3318 set_bit(old_master, iter.node_map);
3319 mlog(0, "doing assert master of %.*s back to %u\n",
3320 res->lockname.len, res->lockname.name, old_master);
3321 ret = dlm_do_assert_master(dlm, res, iter.node_map,
3322 DLM_ASSERT_MASTER_FINISH_MIGRATION);
3323 if (ret < 0) {
3324 mlog(0, "assert master to original master failed "
3325 "with %d.\n", ret);
3326 /* the only nonzero status here would be because of
3327 * a dead original node. we're done. */
3328 ret = 0;
3329 }
3330
3331 /* all done, set the owner, clear the flag */
3332 spin_lock(&res->spinlock);
3333 dlm_set_lockres_owner(dlm, res, dlm->node_num);
3334 res->state &= ~DLM_LOCK_RES_MIGRATING;
3335 spin_unlock(&res->spinlock);
3336 /* re-dirty it on the new master */
3337 dlm_kick_thread(dlm, res);
3338 wake_up(&res->wq);
3339 leave:
3340 return ret;
3341 }
3342
3343 /*
3344 * LOCKRES AST REFCOUNT
3345 * this is integral to migration
3346 */
3347
3348 /* for future intent to call an ast, reserve one ahead of time.
3349 * this should be called only after waiting on the lockres
3350 * with dlm_wait_on_lockres, and while still holding the
3351 * spinlock after the call. */
3352 void __dlm_lockres_reserve_ast(struct dlm_lock_resource *res)
3353 {
3354 assert_spin_locked(&res->spinlock);
3355 if (res->state & DLM_LOCK_RES_MIGRATING) {
3356 __dlm_print_one_lock_resource(res);
3357 }
3358 BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
3359
3360 atomic_inc(&res->asts_reserved);
3361 }
3362
3363 /*
3364 * used to drop the reserved ast, either because it went unused,
3365 * or because the ast/bast was actually called.
3366 *
3367 * also, if there is a pending migration on this lockres,
3368 * and this was the last pending ast on the lockres,
3369 * atomically set the MIGRATING flag before we drop the lock.
3370 * this is how we ensure that migration can proceed with no
3371 * asts in progress. note that it is ok if the state of the
3372 * queues is such that a lock should be granted in the future
3373 * or that a bast should be fired, because the new master will
3374 * shuffle the lists on this lockres as soon as it is migrated.
3375 */
3376 void dlm_lockres_release_ast(struct dlm_ctxt *dlm,
3377 struct dlm_lock_resource *res)
3378 {
3379 if (!atomic_dec_and_lock(&res->asts_reserved, &res->spinlock))
3380 return;
3381
3382 if (!res->migration_pending) {
3383 spin_unlock(&res->spinlock);
3384 return;
3385 }
3386
3387 BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
3388 res->migration_pending = 0;
3389 res->state |= DLM_LOCK_RES_MIGRATING;
3390 spin_unlock(&res->spinlock);
3391 wake_up(&res->wq);
3392 wake_up(&dlm->migration_wq);
3393 }
3394
3395 void dlm_force_free_mles(struct dlm_ctxt *dlm)
3396 {
3397 int i;
3398 struct hlist_head *bucket;
3399 struct dlm_master_list_entry *mle;
3400 struct hlist_node *tmp, *list;
3401
3402 /*
3403 * We notified all other nodes that we are exiting the domain and
3404 * marked the dlm state to DLM_CTXT_LEAVING. If any mles are still
3405 * around we force free them and wake any processes that are waiting
3406 * on the mles
3407 */
3408 spin_lock(&dlm->spinlock);
3409 spin_lock(&dlm->master_lock);
3410
3411 BUG_ON(dlm->dlm_state != DLM_CTXT_LEAVING);
3412 BUG_ON((find_next_bit(dlm->domain_map, O2NM_MAX_NODES, 0) < O2NM_MAX_NODES));
3413
3414 for (i = 0; i < DLM_HASH_BUCKETS; i++) {
3415 bucket = dlm_master_hash(dlm, i);
3416 hlist_for_each_safe(list, tmp, bucket) {
3417 mle = hlist_entry(list, struct dlm_master_list_entry,
3418 master_hash_node);
3419 if (mle->type != DLM_MLE_BLOCK) {
3420 mlog(ML_ERROR, "bad mle: %p\n", mle);
3421 dlm_print_one_mle(mle);
3422 }
3423 atomic_set(&mle->woken, 1);
3424 wake_up(&mle->wq);
3425
3426 __dlm_unlink_mle(dlm, mle);
3427 __dlm_mle_detach_hb_events(dlm, mle);
3428 __dlm_put_mle(mle);
3429 }
3430 }
3431 spin_unlock(&dlm->master_lock);
3432 spin_unlock(&dlm->spinlock);
3433 }
3434
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