projects / linux-2.6-block.git / blame
? search:
summary | shortlog | log | commit | commitdiff | tree
blob | blame (incremental) | history | HEAD
ocfs2: detach mle from heartbeat events
[linux-2.6-block.git] / fs / ocfs2 / dlm / dlmmaster.c
CommitLineData
6714d8e8
KH		 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/utsname.h>
34#include <linux/init.h>
35#include <linux/sysctl.h>
36#include <linux/random.h>
37#include <linux/blkdev.h>
38#include <linux/socket.h>
39#include <linux/inet.h>
40#include <linux/spinlock.h>
41#include <linux/delay.h>
42
43
44#include "cluster/heartbeat.h"
45#include "cluster/nodemanager.h"
46#include "cluster/tcp.h"
47
48#include "dlmapi.h"
49#include "dlmcommon.h"
50#include "dlmdebug.h"
82353b59 51#include "dlmdomain.h"
6714d8e8
KH		 52
53#define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_MASTER)
54#include "cluster/masklog.h"
55
56enum dlm_mle_type {
57 DLM_MLE_BLOCK,
58 DLM_MLE_MASTER,
59 DLM_MLE_MIGRATION
60};
61
62struct dlm_lock_name
63{
64 u8 len;
65 u8 name[DLM_LOCKID_NAME_MAX];
66};
67
68struct dlm_master_list_entry
69{
70 struct list_head list;
71 struct list_head hb_events;
72 struct dlm_ctxt *dlm;
73 spinlock_t spinlock;
74 wait_queue_head_t wq;
75 atomic_t woken;
76 struct kref mle_refs;
a2bf0477 77 int inuse;
6714d8e8
KH		 78 unsigned long maybe_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
79 unsigned long vote_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
80 unsigned long response_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
81 unsigned long node_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
82 u8 master;
83 u8 new_master;
84 enum dlm_mle_type type;
85 struct o2hb_callback_func mle_hb_up;
86 struct o2hb_callback_func mle_hb_down;
87 union {
88 struct dlm_lock_resource *res;
89 struct dlm_lock_name name;
90 } u;
91};
92
93static void dlm_mle_node_down(struct dlm_ctxt *dlm,
94 struct dlm_master_list_entry *mle,
95 struct o2nm_node *node,
96 int idx);
97static void dlm_mle_node_up(struct dlm_ctxt *dlm,
98 struct dlm_master_list_entry *mle,
99 struct o2nm_node *node,
100 int idx);
101
102static void dlm_assert_master_worker(struct dlm_work_item *item, void *data);
103static int dlm_do_assert_master(struct dlm_ctxt *dlm, const char *lockname,
104 unsigned int namelen, void *nodemap,
105 u32 flags);
106
107static inline int dlm_mle_equal(struct dlm_ctxt *dlm,
108 struct dlm_master_list_entry *mle,
109 const char *name,
110 unsigned int namelen)
111{
112 struct dlm_lock_resource *res;
113
114 if (dlm != mle->dlm)
115 return 0;
116
117 if (mle->type == DLM_MLE_BLOCK ||
118 mle->type == DLM_MLE_MIGRATION) {
119 if (namelen != mle->u.name.len ||
120 memcmp(name, mle->u.name.name, namelen)!=0)
121 return 0;
122 } else {
123 res = mle->u.res;
124 if (namelen != res->lockname.len ||
125 memcmp(res->lockname.name, name, namelen) != 0)
126 return 0;
127 }
128 return 1;
129}
130
131#if 0
132/* Code here is included but defined out as it aids debugging */
133
95883719
KH		 134#define dlm_print_nodemap(m) _dlm_print_nodemap(m,#m)
135void _dlm_print_nodemap(unsigned long *map, const char *mapname)
136{
137 int i;
138 printk("%s=[ ", mapname);
139 for (i=0; i<O2NM_MAX_NODES; i++)
140 if (test_bit(i, map))
141 printk("%d ", i);
142 printk("]");
143}
144
6714d8e8
KH		 145void dlm_print_one_mle(struct dlm_master_list_entry *mle)
146{
95883719 147 int refs;
6714d8e8
KH		 148 char *type;
149 char attached;
150 u8 master;
151 unsigned int namelen;
152 const char *name;
153 struct kref *k;
95883719
KH		 154 unsigned long *maybe = mle->maybe_map,
155 *vote = mle->vote_map,
156 *resp = mle->response_map,
157 *node = mle->node_map;
6714d8e8
KH		 158
159 k = &mle->mle_refs;
160 if (mle->type == DLM_MLE_BLOCK)
161 type = "BLK";
162 else if (mle->type == DLM_MLE_MASTER)
163 type = "MAS";
164 else
165 type = "MIG";
166 refs = atomic_read(&k->refcount);
167 master = mle->master;
168 attached = (list_empty(&mle->hb_events) ? 'N' : 'Y');
169
170 if (mle->type != DLM_MLE_MASTER) {
171 namelen = mle->u.name.len;
172 name = mle->u.name.name;
173 } else {
174 namelen = mle->u.res->lockname.len;
175 name = mle->u.res->lockname.name;
176 }
177
95883719
KH		 178 mlog(ML_NOTICE, "%.*s: %3s refs=%3d mas=%3u new=%3u evt=%c inuse=%d ",
179 namelen, name, type, refs, master, mle->new_master, attached,
180 mle->inuse);
181 dlm_print_nodemap(maybe);
182 printk(", ");
183 dlm_print_nodemap(vote);
184 printk(", ");
185 dlm_print_nodemap(resp);
186 printk(", ");
187 dlm_print_nodemap(node);
188 printk(", ");
189 printk("\n");
6714d8e8
KH		 190}
191
192static void dlm_dump_mles(struct dlm_ctxt *dlm)
193{
194 struct dlm_master_list_entry *mle;
195 struct list_head *iter;
196
197 mlog(ML_NOTICE, "dumping all mles for domain %s:\n", dlm->name);
6714d8e8
KH		 198 spin_lock(&dlm->master_lock);
199 list_for_each(iter, &dlm->master_list) {
200 mle = list_entry(iter, struct dlm_master_list_entry, list);
201 dlm_print_one_mle(mle);
202 }
203 spin_unlock(&dlm->master_lock);
204}
205
6714d8e8
KH		 206int dlm_dump_all_mles(const char __user *data, unsigned int len)
207{
208 struct list_head *iter;
209 struct dlm_ctxt *dlm;
210
211 spin_lock(&dlm_domain_lock);
212 list_for_each(iter, &dlm_domains) {
213 dlm = list_entry (iter, struct dlm_ctxt, list);
214 mlog(ML_NOTICE, "found dlm: %p, name=%s\n", dlm, dlm->name);
215 dlm_dump_mles(dlm);
216 }
217 spin_unlock(&dlm_domain_lock);
218 return len;
219}
220EXPORT_SYMBOL_GPL(dlm_dump_all_mles);
221
222#endif /* 0 */
223
224
225static kmem_cache_t *dlm_mle_cache = NULL;
226
227
228static void dlm_mle_release(struct kref *kref);
229static void dlm_init_mle(struct dlm_master_list_entry *mle,
230 enum dlm_mle_type type,
231 struct dlm_ctxt *dlm,
232 struct dlm_lock_resource *res,
233 const char *name,
234 unsigned int namelen);
235static void dlm_put_mle(struct dlm_master_list_entry *mle);
236static void __dlm_put_mle(struct dlm_master_list_entry *mle);
237static int dlm_find_mle(struct dlm_ctxt *dlm,
238 struct dlm_master_list_entry **mle,
239 char *name, unsigned int namelen);
240
241static int dlm_do_master_request(struct dlm_master_list_entry *mle, int to);
242
243
244static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
245 struct dlm_lock_resource *res,
246 struct dlm_master_list_entry *mle,
247 int *blocked);
248static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
249 struct dlm_lock_resource *res,
250 struct dlm_master_list_entry *mle,
251 int blocked);
252static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
253 struct dlm_lock_resource *res,
254 struct dlm_master_list_entry *mle,
255 struct dlm_master_list_entry **oldmle,
256 const char *name, unsigned int namelen,
257 u8 new_master, u8 master);
258
259static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
260 struct dlm_lock_resource *res);
261static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
262 struct dlm_lock_resource *res);
263static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
264 struct dlm_lock_resource *res,
265 u8 target);
c03872f5
KH		 266static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
267 struct dlm_lock_resource *res);
6714d8e8
KH		 268
269
270int dlm_is_host_down(int errno)
271{
272 switch (errno) {
273 case -EBADF:
274 case -ECONNREFUSED:
275 case -ENOTCONN:
276 case -ECONNRESET:
277 case -EPIPE:
278 case -EHOSTDOWN:
279 case -EHOSTUNREACH:
280 case -ETIMEDOUT:
281 case -ECONNABORTED:
282 case -ENETDOWN:
283 case -ENETUNREACH:
284 case -ENETRESET:
285 case -ESHUTDOWN:
286 case -ENOPROTOOPT:
287 case -EINVAL: /* if returned from our tcp code,
288 this means there is no socket */
289 return 1;
290 }
291 return 0;
292}
293
294
295/*
296 * MASTER LIST FUNCTIONS
297 */
298
299
300/*
301 * regarding master list entries and heartbeat callbacks:
302 *
303 * in order to avoid sleeping and allocation that occurs in
304 * heartbeat, master list entries are simply attached to the
305 * dlm's established heartbeat callbacks. the mle is attached
306 * when it is created, and since the dlm->spinlock is held at
307 * that time, any heartbeat event will be properly discovered
308 * by the mle. the mle needs to be detached from the
309 * dlm->mle_hb_events list as soon as heartbeat events are no
310 * longer useful to the mle, and before the mle is freed.
311 *
312 * as a general rule, heartbeat events are no longer needed by
313 * the mle once an "answer" regarding the lock master has been
314 * received.
315 */
316static inline void __dlm_mle_attach_hb_events(struct dlm_ctxt *dlm,
317 struct dlm_master_list_entry *mle)
318{
319 assert_spin_locked(&dlm->spinlock);
320
321 list_add_tail(&mle->hb_events, &dlm->mle_hb_events);
322}
323
324
325static inline void __dlm_mle_detach_hb_events(struct dlm_ctxt *dlm,
326 struct dlm_master_list_entry *mle)
327{
328 if (!list_empty(&mle->hb_events))
329 list_del_init(&mle->hb_events);
330}
331
332
333static inline void dlm_mle_detach_hb_events(struct dlm_ctxt *dlm,
334 struct dlm_master_list_entry *mle)
335{
336 spin_lock(&dlm->spinlock);
337 __dlm_mle_detach_hb_events(dlm, mle);
338 spin_unlock(&dlm->spinlock);
339}
340
a2bf0477
KH		 341static void dlm_get_mle_inuse(struct dlm_master_list_entry *mle)
342{
343 struct dlm_ctxt *dlm;
344 dlm = mle->dlm;
345
346 assert_spin_locked(&dlm->spinlock);
347 assert_spin_locked(&dlm->master_lock);
348 mle->inuse++;
349 kref_get(&mle->mle_refs);
350}
351
352static void dlm_put_mle_inuse(struct dlm_master_list_entry *mle)
353{
354 struct dlm_ctxt *dlm;
355 dlm = mle->dlm;
356
357 spin_lock(&dlm->spinlock);
358 spin_lock(&dlm->master_lock);
359 mle->inuse--;
360 __dlm_put_mle(mle);
361 spin_unlock(&dlm->master_lock);
362 spin_unlock(&dlm->spinlock);
363
364}
365
6714d8e8
KH		 366/* remove from list and free */
367static void __dlm_put_mle(struct dlm_master_list_entry *mle)
368{
369 struct dlm_ctxt *dlm;
370 dlm = mle->dlm;
371
372 assert_spin_locked(&dlm->spinlock);
373 assert_spin_locked(&dlm->master_lock);
374 BUG_ON(!atomic_read(&mle->mle_refs.refcount));
375
376 kref_put(&mle->mle_refs, dlm_mle_release);
377}
378
379
380/* must not have any spinlocks coming in */
381static void dlm_put_mle(struct dlm_master_list_entry *mle)
382{
383 struct dlm_ctxt *dlm;
384 dlm = mle->dlm;
385
386 spin_lock(&dlm->spinlock);
387 spin_lock(&dlm->master_lock);
388 __dlm_put_mle(mle);
389 spin_unlock(&dlm->master_lock);
390 spin_unlock(&dlm->spinlock);
391}
392
393static inline void dlm_get_mle(struct dlm_master_list_entry *mle)
394{
395 kref_get(&mle->mle_refs);
396}
397
398static void dlm_init_mle(struct dlm_master_list_entry *mle,
399 enum dlm_mle_type type,
400 struct dlm_ctxt *dlm,
401 struct dlm_lock_resource *res,
402 const char *name,
403 unsigned int namelen)
404{
405 assert_spin_locked(&dlm->spinlock);
406
407 mle->dlm = dlm;
408 mle->type = type;
409 INIT_LIST_HEAD(&mle->list);
410 INIT_LIST_HEAD(&mle->hb_events);
411 memset(mle->maybe_map, 0, sizeof(mle->maybe_map));
412 spin_lock_init(&mle->spinlock);
413 init_waitqueue_head(&mle->wq);
414 atomic_set(&mle->woken, 0);
415 kref_init(&mle->mle_refs);
416 memset(mle->response_map, 0, sizeof(mle->response_map));
417 mle->master = O2NM_MAX_NODES;
418 mle->new_master = O2NM_MAX_NODES;
a2bf0477 419 mle->inuse = 0;
6714d8e8
KH		 420
421 if (mle->type == DLM_MLE_MASTER) {
422 BUG_ON(!res);
423 mle->u.res = res;
424 } else if (mle->type == DLM_MLE_BLOCK) {
425 BUG_ON(!name);
426 memcpy(mle->u.name.name, name, namelen);
427 mle->u.name.len = namelen;
428 } else /* DLM_MLE_MIGRATION */ {
429 BUG_ON(!name);
430 memcpy(mle->u.name.name, name, namelen);
431 mle->u.name.len = namelen;
432 }
433
434 /* copy off the node_map and register hb callbacks on our copy */
435 memcpy(mle->node_map, dlm->domain_map, sizeof(mle->node_map));
436 memcpy(mle->vote_map, dlm->domain_map, sizeof(mle->vote_map));
437 clear_bit(dlm->node_num, mle->vote_map);
438 clear_bit(dlm->node_num, mle->node_map);
439
440 /* attach the mle to the domain node up/down events */
441 __dlm_mle_attach_hb_events(dlm, mle);
442}
443
444
445/* returns 1 if found, 0 if not */
446static int dlm_find_mle(struct dlm_ctxt *dlm,
447 struct dlm_master_list_entry **mle,
448 char *name, unsigned int namelen)
449{
450 struct dlm_master_list_entry *tmpmle;
451 struct list_head *iter;
452
453 assert_spin_locked(&dlm->master_lock);
454
455 list_for_each(iter, &dlm->master_list) {
456 tmpmle = list_entry(iter, struct dlm_master_list_entry, list);
457 if (!dlm_mle_equal(dlm, tmpmle, name, namelen))
458 continue;
459 dlm_get_mle(tmpmle);
460 *mle = tmpmle;
461 return 1;
462 }
463 return 0;
464}
465
466void dlm_hb_event_notify_attached(struct dlm_ctxt *dlm, int idx, int node_up)
467{
468 struct dlm_master_list_entry *mle;
469 struct list_head *iter;
470
471 assert_spin_locked(&dlm->spinlock);
472
473 list_for_each(iter, &dlm->mle_hb_events) {
474 mle = list_entry(iter, struct dlm_master_list_entry,
475 hb_events);
476 if (node_up)
477 dlm_mle_node_up(dlm, mle, NULL, idx);
478 else
479 dlm_mle_node_down(dlm, mle, NULL, idx);
480 }
481}
482
483static void dlm_mle_node_down(struct dlm_ctxt *dlm,
484 struct dlm_master_list_entry *mle,
485 struct o2nm_node *node, int idx)
486{
487 spin_lock(&mle->spinlock);
488
489 if (!test_bit(idx, mle->node_map))
490 mlog(0, "node %u already removed from nodemap!\n", idx);
491 else
492 clear_bit(idx, mle->node_map);
493
494 spin_unlock(&mle->spinlock);
495}
496
497static void dlm_mle_node_up(struct dlm_ctxt *dlm,
498 struct dlm_master_list_entry *mle,
499 struct o2nm_node *node, int idx)
500{
501 spin_lock(&mle->spinlock);
502
503 if (test_bit(idx, mle->node_map))
504 mlog(0, "node %u already in node map!\n", idx);
505 else
506 set_bit(idx, mle->node_map);
507
508 spin_unlock(&mle->spinlock);
509}
510
511
512int dlm_init_mle_cache(void)
513{
514 dlm_mle_cache = kmem_cache_create("dlm_mle_cache",
515 sizeof(struct dlm_master_list_entry),
516 0, SLAB_HWCACHE_ALIGN,
517 NULL, NULL);
518 if (dlm_mle_cache == NULL)
519 return -ENOMEM;
520 return 0;
521}
522
523void dlm_destroy_mle_cache(void)
524{
525 if (dlm_mle_cache)
526 kmem_cache_destroy(dlm_mle_cache);
527}
528
529static void dlm_mle_release(struct kref *kref)
530{
531 struct dlm_master_list_entry *mle;
532 struct dlm_ctxt *dlm;
533
534 mlog_entry_void();
535
536 mle = container_of(kref, struct dlm_master_list_entry, mle_refs);
537 dlm = mle->dlm;
538
539 if (mle->type != DLM_MLE_MASTER) {
540 mlog(0, "calling mle_release for %.*s, type %d\n",
541 mle->u.name.len, mle->u.name.name, mle->type);
542 } else {
543 mlog(0, "calling mle_release for %.*s, type %d\n",
544 mle->u.res->lockname.len,
545 mle->u.res->lockname.name, mle->type);
546 }
547 assert_spin_locked(&dlm->spinlock);
548 assert_spin_locked(&dlm->master_lock);
549
550 /* remove from list if not already */
551 if (!list_empty(&mle->list))
552 list_del_init(&mle->list);
553
554 /* detach the mle from the domain node up/down events */
555 __dlm_mle_detach_hb_events(dlm, mle);
556
557 /* NOTE: kfree under spinlock here.
558 * if this is bad, we can move this to a freelist. */
559 kmem_cache_free(dlm_mle_cache, mle);
560}
561
562
563/*
564 * LOCK RESOURCE FUNCTIONS
565 */
566
567static void dlm_set_lockres_owner(struct dlm_ctxt *dlm,
568 struct dlm_lock_resource *res,
569 u8 owner)
570{
571 assert_spin_locked(&res->spinlock);
572
573 mlog_entry("%.*s, %u\n", res->lockname.len, res->lockname.name, owner);
574
575 if (owner == dlm->node_num)
576 atomic_inc(&dlm->local_resources);
577 else if (owner == DLM_LOCK_RES_OWNER_UNKNOWN)
578 atomic_inc(&dlm->unknown_resources);
579 else
580 atomic_inc(&dlm->remote_resources);
581
582 res->owner = owner;
583}
584
585void dlm_change_lockres_owner(struct dlm_ctxt *dlm,
586 struct dlm_lock_resource *res, u8 owner)
587{
588 assert_spin_locked(&res->spinlock);
589
590 if (owner == res->owner)
591 return;
592
593 if (res->owner == dlm->node_num)
594 atomic_dec(&dlm->local_resources);
595 else if (res->owner == DLM_LOCK_RES_OWNER_UNKNOWN)
596 atomic_dec(&dlm->unknown_resources);
597 else
598 atomic_dec(&dlm->remote_resources);
599
600 dlm_set_lockres_owner(dlm, res, owner);
601}
602
603
604static void dlm_lockres_release(struct kref *kref)
605{
606 struct dlm_lock_resource *res;
607
608 res = container_of(kref, struct dlm_lock_resource, refs);
609
610 /* This should not happen -- all lockres' have a name
611 * associated with them at init time. */
612 BUG_ON(!res->lockname.name);
613
614 mlog(0, "destroying lockres %.*s\n", res->lockname.len,
615 res->lockname.name);
616
617 /* By the time we're ready to blow this guy away, we shouldn't
618 * be on any lists. */
81f2094a 619 BUG_ON(!hlist_unhashed(&res->hash_node));
6714d8e8
KH		 620 BUG_ON(!list_empty(&res->granted));
621 BUG_ON(!list_empty(&res->converting));
622 BUG_ON(!list_empty(&res->blocked));
623 BUG_ON(!list_empty(&res->dirty));
624 BUG_ON(!list_empty(&res->recovering));
625 BUG_ON(!list_empty(&res->purge));
626
627 kfree(res->lockname.name);
628
629 kfree(res);
630}
631
6714d8e8
KH		 632void dlm_lockres_put(struct dlm_lock_resource *res)
633{
634 kref_put(&res->refs, dlm_lockres_release);
635}
636
637static void dlm_init_lockres(struct dlm_ctxt *dlm,
638 struct dlm_lock_resource *res,
639 const char *name, unsigned int namelen)
640{
641 char *qname;
642
643 /* If we memset here, we lose our reference to the kmalloc'd
644 * res->lockname.name, so be sure to init every field
645 * correctly! */
646
647 qname = (char *) res->lockname.name;
648 memcpy(qname, name, namelen);
649
650 res->lockname.len = namelen;
a3d33291 651 res->lockname.hash = dlm_lockid_hash(name, namelen);
6714d8e8
KH		 652
653 init_waitqueue_head(&res->wq);
654 spin_lock_init(&res->spinlock);
81f2094a 655 INIT_HLIST_NODE(&res->hash_node);
6714d8e8
KH		 656 INIT_LIST_HEAD(&res->granted);
657 INIT_LIST_HEAD(&res->converting);
658 INIT_LIST_HEAD(&res->blocked);
659 INIT_LIST_HEAD(&res->dirty);
660 INIT_LIST_HEAD(&res->recovering);
661 INIT_LIST_HEAD(&res->purge);
662 atomic_set(&res->asts_reserved, 0);
663 res->migration_pending = 0;
664
665 kref_init(&res->refs);
666
667 /* just for consistency */
668 spin_lock(&res->spinlock);
669 dlm_set_lockres_owner(dlm, res, DLM_LOCK_RES_OWNER_UNKNOWN);
670 spin_unlock(&res->spinlock);
671
672 res->state = DLM_LOCK_RES_IN_PROGRESS;
673
674 res->last_used = 0;
675
676 memset(res->lvb, 0, DLM_LVB_LEN);
677}
678
679struct dlm_lock_resource *dlm_new_lockres(struct dlm_ctxt *dlm,
680 const char *name,
681 unsigned int namelen)
682{
683 struct dlm_lock_resource *res;
684
685 res = kmalloc(sizeof(struct dlm_lock_resource), GFP_KERNEL);
686 if (!res)
687 return NULL;
688
689 res->lockname.name = kmalloc(namelen, GFP_KERNEL);
690 if (!res->lockname.name) {
691 kfree(res);
692 return NULL;
693 }
694
695 dlm_init_lockres(dlm, res, name, namelen);
696 return res;
697}
698
699/*
700 * lookup a lock resource by name.
701 * may already exist in the hashtable.
702 * lockid is null terminated
703 *
704 * if not, allocate enough for the lockres and for
705 * the temporary structure used in doing the mastering.
706 *
707 * also, do a lookup in the dlm->master_list to see
708 * if another node has begun mastering the same lock.
709 * if so, there should be a block entry in there
710 * for this name, and we should *not* attempt to master
711 * the lock here. need to wait around for that node
712 * to assert_master (or die).
713 *
714 */
715struct dlm_lock_resource * dlm_get_lock_resource(struct dlm_ctxt *dlm,
716 const char *lockid,
717 int flags)
718{
719 struct dlm_lock_resource *tmpres=NULL, *res=NULL;
720 struct dlm_master_list_entry *mle = NULL;
721 struct dlm_master_list_entry *alloc_mle = NULL;
722 int blocked = 0;
723 int ret, nodenum;
724 struct dlm_node_iter iter;
a3d33291 725 unsigned int namelen, hash;
6714d8e8 726 int tries = 0;
c03872f5 727 int bit, wait_on_recovery = 0;
6714d8e8
KH		 728
729 BUG_ON(!lockid);
730
731 namelen = strlen(lockid);
a3d33291 732 hash = dlm_lockid_hash(lockid, namelen);
6714d8e8
KH		 733
734 mlog(0, "get lockres %s (len %d)\n", lockid, namelen);
735
736lookup:
737 spin_lock(&dlm->spinlock);
a3d33291 738 tmpres = __dlm_lookup_lockres(dlm, lockid, namelen, hash);
6714d8e8
KH		 739 if (tmpres) {
740 spin_unlock(&dlm->spinlock);
741 mlog(0, "found in hash!\n");
742 if (res)
743 dlm_lockres_put(res);
744 res = tmpres;
745 goto leave;
746 }
747
748 if (!res) {
749 spin_unlock(&dlm->spinlock);
750 mlog(0, "allocating a new resource\n");
751 /* nothing found and we need to allocate one. */
752 alloc_mle = (struct dlm_master_list_entry *)
753 kmem_cache_alloc(dlm_mle_cache, GFP_KERNEL);
754 if (!alloc_mle)
755 goto leave;
756 res = dlm_new_lockres(dlm, lockid, namelen);
757 if (!res)
758 goto leave;
759 goto lookup;
760 }
761
762 mlog(0, "no lockres found, allocated our own: %p\n", res);
763
764 if (flags & LKM_LOCAL) {
765 /* caller knows it's safe to assume it's not mastered elsewhere
766 * DONE! return right away */
767 spin_lock(&res->spinlock);
768 dlm_change_lockres_owner(dlm, res, dlm->node_num);
769 __dlm_insert_lockres(dlm, res);
770 spin_unlock(&res->spinlock);
771 spin_unlock(&dlm->spinlock);
772 /* lockres still marked IN_PROGRESS */
773 goto wake_waiters;
774 }
775
776 /* check master list to see if another node has started mastering it */
777 spin_lock(&dlm->master_lock);
778
779 /* if we found a block, wait for lock to be mastered by another node */
780 blocked = dlm_find_mle(dlm, &mle, (char *)lockid, namelen);
781 if (blocked) {
782 if (mle->type == DLM_MLE_MASTER) {
783 mlog(ML_ERROR, "master entry for nonexistent lock!\n");
784 BUG();
785 } else if (mle->type == DLM_MLE_MIGRATION) {
786 /* migration is in progress! */
787 /* the good news is that we now know the
788 * "current" master (mle->master). */
789
790 spin_unlock(&dlm->master_lock);
791 assert_spin_locked(&dlm->spinlock);
792
793 /* set the lockres owner and hash it */
794 spin_lock(&res->spinlock);
795 dlm_set_lockres_owner(dlm, res, mle->master);
796 __dlm_insert_lockres(dlm, res);
797 spin_unlock(&res->spinlock);
798 spin_unlock(&dlm->spinlock);
799
800 /* master is known, detach */
801 dlm_mle_detach_hb_events(dlm, mle);
802 dlm_put_mle(mle);
803 mle = NULL;
804 goto wake_waiters;
805 }
806 } else {
807 /* go ahead and try to master lock on this node */
808 mle = alloc_mle;
809 /* make sure this does not get freed below */
810 alloc_mle = NULL;
811 dlm_init_mle(mle, DLM_MLE_MASTER, dlm, res, NULL, 0);
812 set_bit(dlm->node_num, mle->maybe_map);
813 list_add(&mle->list, &dlm->master_list);
c03872f5
KH		 814
815 /* still holding the dlm spinlock, check the recovery map
816 * to see if there are any nodes that still need to be
817 * considered. these will not appear in the mle nodemap
818 * but they might own this lockres. wait on them. */
819 bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
820 if (bit < O2NM_MAX_NODES) {
821 mlog(ML_NOTICE, "%s:%.*s: at least one node (%d) to"
822 "recover before lock mastery can begin\n",
823 dlm->name, namelen, (char *)lockid, bit);
824 wait_on_recovery = 1;
825 }
6714d8e8
KH		 826 }
827
828 /* at this point there is either a DLM_MLE_BLOCK or a
829 * DLM_MLE_MASTER on the master list, so it's safe to add the
830 * lockres to the hashtable. anyone who finds the lock will
831 * still have to wait on the IN_PROGRESS. */
832
833 /* finally add the lockres to its hash bucket */
834 __dlm_insert_lockres(dlm, res);
835 /* get an extra ref on the mle in case this is a BLOCK
836 * if so, the creator of the BLOCK may try to put the last
837 * ref at this time in the assert master handler, so we
838 * need an extra one to keep from a bad ptr deref. */
a2bf0477 839 dlm_get_mle_inuse(mle);
6714d8e8
KH		 840 spin_unlock(&dlm->master_lock);
841 spin_unlock(&dlm->spinlock);
842
c03872f5
KH		 843 while (wait_on_recovery) {
844 /* any cluster changes that occurred after dropping the
845 * dlm spinlock would be detectable be a change on the mle,
846 * so we only need to clear out the recovery map once. */
847 if (dlm_is_recovery_lock(lockid, namelen)) {
848 mlog(ML_NOTICE, "%s: recovery map is not empty, but "
849 "must master $RECOVERY lock now\n", dlm->name);
850 if (!dlm_pre_master_reco_lockres(dlm, res))
851 wait_on_recovery = 0;
852 else {
853 mlog(0, "%s: waiting 500ms for heartbeat state "
854 "change\n", dlm->name);
855 msleep(500);
856 }
857 continue;
858 }
859
860 dlm_kick_recovery_thread(dlm);
861 msleep(100);
862 dlm_wait_for_recovery(dlm);
863
864 spin_lock(&dlm->spinlock);
865 bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
866 if (bit < O2NM_MAX_NODES) {
867 mlog(ML_NOTICE, "%s:%.*s: at least one node (%d) to"
868 "recover before lock mastery can begin\n",
869 dlm->name, namelen, (char *)lockid, bit);
870 wait_on_recovery = 1;
871 } else
872 wait_on_recovery = 0;
873 spin_unlock(&dlm->spinlock);
874 }
875
6714d8e8
KH		 876 /* must wait for lock to be mastered elsewhere */
877 if (blocked)
878 goto wait;
879
880redo_request:
881 ret = -EINVAL;
882 dlm_node_iter_init(mle->vote_map, &iter);
883 while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
884 ret = dlm_do_master_request(mle, nodenum);
885 if (ret < 0)
886 mlog_errno(ret);
887 if (mle->master != O2NM_MAX_NODES) {
888 /* found a master ! */
9c6510a5
KH		 889 if (mle->master <= nodenum)
890 break;
891 /* if our master request has not reached the master
892 * yet, keep going until it does. this is how the
893 * master will know that asserts are needed back to
894 * the lower nodes. */
895 mlog(0, "%s:%.*s: requests only up to %u but master "
896 "is %u, keep going\n", dlm->name, namelen,
897 lockid, nodenum, mle->master);
6714d8e8
KH		 898 }
899 }
900
901wait:
902 /* keep going until the response map includes all nodes */
903 ret = dlm_wait_for_lock_mastery(dlm, res, mle, &blocked);
904 if (ret < 0) {
905 mlog(0, "%s:%.*s: node map changed, redo the "
906 "master request now, blocked=%d\n",
907 dlm->name, res->lockname.len,
908 res->lockname.name, blocked);
909 if (++tries > 20) {
910 mlog(ML_ERROR, "%s:%.*s: spinning on "
911 "dlm_wait_for_lock_mastery, blocked=%d\n",
912 dlm->name, res->lockname.len,
913 res->lockname.name, blocked);
914 dlm_print_one_lock_resource(res);
915 /* dlm_print_one_mle(mle); */
916 tries = 0;
917 }
918 goto redo_request;
919 }
920
921 mlog(0, "lockres mastered by %u\n", res->owner);
922 /* make sure we never continue without this */
923 BUG_ON(res->owner == O2NM_MAX_NODES);
924
925 /* master is known, detach if not already detached */
926 dlm_mle_detach_hb_events(dlm, mle);
927 dlm_put_mle(mle);
928 /* put the extra ref */
a2bf0477 929 dlm_put_mle_inuse(mle);
6714d8e8
KH		 930
931wake_waiters:
932 spin_lock(&res->spinlock);
933 res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
934 spin_unlock(&res->spinlock);
935 wake_up(&res->wq);
936
937leave:
938 /* need to free the unused mle */
939 if (alloc_mle)
940 kmem_cache_free(dlm_mle_cache, alloc_mle);
941
942 return res;
943}
944
945
946#define DLM_MASTERY_TIMEOUT_MS 5000
947
948static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
949 struct dlm_lock_resource *res,
950 struct dlm_master_list_entry *mle,
951 int *blocked)
952{
953 u8 m;
954 int ret, bit;
955 int map_changed, voting_done;
956 int assert, sleep;
957
958recheck:
959 ret = 0;
960 assert = 0;
961
962 /* check if another node has already become the owner */
963 spin_lock(&res->spinlock);
964 if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
9c6510a5
KH		 965 mlog(0, "%s:%.*s: owner is suddenly %u\n", dlm->name,
966 res->lockname.len, res->lockname.name, res->owner);
6714d8e8 967 spin_unlock(&res->spinlock);
9c6510a5
KH		 968 /* this will cause the master to re-assert across
969 * the whole cluster, freeing up mles */
970 ret = dlm_do_master_request(mle, res->owner);
971 if (ret < 0) {
972 /* give recovery a chance to run */
973 mlog(ML_ERROR, "link to %u went down?: %d\n", res->owner, ret);
974 msleep(500);
975 goto recheck;
976 }
977 ret = 0;
6714d8e8
KH		 978 goto leave;
979 }
980 spin_unlock(&res->spinlock);
981
982 spin_lock(&mle->spinlock);
983 m = mle->master;
984 map_changed = (memcmp(mle->vote_map, mle->node_map,
985 sizeof(mle->vote_map)) != 0);
986 voting_done = (memcmp(mle->vote_map, mle->response_map,
987 sizeof(mle->vote_map)) == 0);
988
989 /* restart if we hit any errors */
990 if (map_changed) {
991 int b;
992 mlog(0, "%s: %.*s: node map changed, restarting\n",
993 dlm->name, res->lockname.len, res->lockname.name);
994 ret = dlm_restart_lock_mastery(dlm, res, mle, *blocked);
995 b = (mle->type == DLM_MLE_BLOCK);
996 if ((*blocked && !b) || (!*blocked && b)) {
997 mlog(0, "%s:%.*s: status change: old=%d new=%d\n",
998 dlm->name, res->lockname.len, res->lockname.name,
999 *blocked, b);
1000 *blocked = b;
1001 }
1002 spin_unlock(&mle->spinlock);
1003 if (ret < 0) {
1004 mlog_errno(ret);
1005 goto leave;
1006 }
1007 mlog(0, "%s:%.*s: restart lock mastery succeeded, "
1008 "rechecking now\n", dlm->name, res->lockname.len,
1009 res->lockname.name);
1010 goto recheck;
1011 }
1012
1013 if (m != O2NM_MAX_NODES) {
1014 /* another node has done an assert!
1015 * all done! */
1016 sleep = 0;
1017 } else {
1018 sleep = 1;
1019 /* have all nodes responded? */
1020 if (voting_done && !*blocked) {
1021 bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
1022 if (dlm->node_num <= bit) {
1023 /* my node number is lowest.
1024 * now tell other nodes that I am
1025 * mastering this. */
1026 mle->master = dlm->node_num;
1027 assert = 1;
1028 sleep = 0;
1029 }
1030 /* if voting is done, but we have not received
1031 * an assert master yet, we must sleep */
1032 }
1033 }
1034
1035 spin_unlock(&mle->spinlock);
1036
1037 /* sleep if we haven't finished voting yet */
1038 if (sleep) {
1039 unsigned long timeo = msecs_to_jiffies(DLM_MASTERY_TIMEOUT_MS);
1040
1041 /*
1042 if (atomic_read(&mle->mle_refs.refcount) < 2)
1043 mlog(ML_ERROR, "mle (%p) refs=%d, name=%.*s\n", mle,
1044 atomic_read(&mle->mle_refs.refcount),
1045 res->lockname.len, res->lockname.name);
1046 */
1047 atomic_set(&mle->woken, 0);
1048 (void)wait_event_timeout(mle->wq,
1049 (atomic_read(&mle->woken) == 1),
1050 timeo);
1051 if (res->owner == O2NM_MAX_NODES) {
1052 mlog(0, "waiting again\n");
1053 goto recheck;
1054 }
1055 mlog(0, "done waiting, master is %u\n", res->owner);
1056 ret = 0;
1057 goto leave;
1058 }
1059
1060 ret = 0; /* done */
1061 if (assert) {
1062 m = dlm->node_num;
1063 mlog(0, "about to master %.*s here, this=%u\n",
1064 res->lockname.len, res->lockname.name, m);
1065 ret = dlm_do_assert_master(dlm, res->lockname.name,
1066 res->lockname.len, mle->vote_map, 0);
1067 if (ret) {
1068 /* This is a failure in the network path,
1069 * not in the response to the assert_master
1070 * (any nonzero response is a BUG on this node).
1071 * Most likely a socket just got disconnected
1072 * due to node death. */
1073 mlog_errno(ret);
1074 }
1075 /* no longer need to restart lock mastery.
1076 * all living nodes have been contacted. */
1077 ret = 0;
1078 }
1079
1080 /* set the lockres owner */
1081 spin_lock(&res->spinlock);
1082 dlm_change_lockres_owner(dlm, res, m);
1083 spin_unlock(&res->spinlock);
1084
1085leave:
1086 return ret;
1087}
1088
1089struct dlm_bitmap_diff_iter
1090{
1091 int curnode;
1092 unsigned long *orig_bm;
1093 unsigned long *cur_bm;
1094 unsigned long diff_bm[BITS_TO_LONGS(O2NM_MAX_NODES)];
1095};
1096
1097enum dlm_node_state_change
1098{
1099 NODE_DOWN = -1,
1100 NODE_NO_CHANGE = 0,
1101 NODE_UP
1102};
1103
1104static void dlm_bitmap_diff_iter_init(struct dlm_bitmap_diff_iter *iter,
1105 unsigned long *orig_bm,
1106 unsigned long *cur_bm)
1107{
1108 unsigned long p1, p2;
1109 int i;
1110
1111 iter->curnode = -1;
1112 iter->orig_bm = orig_bm;
1113 iter->cur_bm = cur_bm;
1114
1115 for (i = 0; i < BITS_TO_LONGS(O2NM_MAX_NODES); i++) {
1116 p1 = *(iter->orig_bm + i);
1117 p2 = *(iter->cur_bm + i);
1118 iter->diff_bm[i] = (p1 & ~p2) | (p2 & ~p1);
1119 }
1120}
1121
1122static int dlm_bitmap_diff_iter_next(struct dlm_bitmap_diff_iter *iter,
1123 enum dlm_node_state_change *state)
1124{
1125 int bit;
1126
1127 if (iter->curnode >= O2NM_MAX_NODES)
1128 return -ENOENT;
1129
1130 bit = find_next_bit(iter->diff_bm, O2NM_MAX_NODES,
1131 iter->curnode+1);
1132 if (bit >= O2NM_MAX_NODES) {
1133 iter->curnode = O2NM_MAX_NODES;
1134 return -ENOENT;
1135 }
1136
1137 /* if it was there in the original then this node died */
1138 if (test_bit(bit, iter->orig_bm))
1139 *state = NODE_DOWN;
1140 else
1141 *state = NODE_UP;
1142
1143 iter->curnode = bit;
1144 return bit;
1145}
1146
1147
1148static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
1149 struct dlm_lock_resource *res,
1150 struct dlm_master_list_entry *mle,
1151 int blocked)
1152{
1153 struct dlm_bitmap_diff_iter bdi;
1154 enum dlm_node_state_change sc;
1155 int node;
1156 int ret = 0;
1157
1158 mlog(0, "something happened such that the "
1159 "master process may need to be restarted!\n");
1160
1161 assert_spin_locked(&mle->spinlock);
1162
1163 dlm_bitmap_diff_iter_init(&bdi, mle->vote_map, mle->node_map);
1164 node = dlm_bitmap_diff_iter_next(&bdi, &sc);
1165 while (node >= 0) {
1166 if (sc == NODE_UP) {
e2faea4c
KH		 1167 /* a node came up. clear any old vote from
1168 * the response map and set it in the vote map
1169 * then restart the mastery. */
1170 mlog(ML_NOTICE, "node %d up while restarting\n", node);
6714d8e8
KH		 1171
1172 /* redo the master request, but only for the new node */
1173 mlog(0, "sending request to new node\n");
1174 clear_bit(node, mle->response_map);
1175 set_bit(node, mle->vote_map);
1176 } else {
1177 mlog(ML_ERROR, "node down! %d\n", node);
1178
1179 /* if the node wasn't involved in mastery skip it,
1180 * but clear it out from the maps so that it will
1181 * not affect mastery of this lockres */
1182 clear_bit(node, mle->response_map);
1183 clear_bit(node, mle->vote_map);
1184 if (!test_bit(node, mle->maybe_map))
1185 goto next;
1186
1187 /* if we're already blocked on lock mastery, and the
1188 * dead node wasn't the expected master, or there is
1189 * another node in the maybe_map, keep waiting */
1190 if (blocked) {
1191 int lowest = find_next_bit(mle->maybe_map,
1192 O2NM_MAX_NODES, 0);
1193
1194 /* act like it was never there */
1195 clear_bit(node, mle->maybe_map);
1196
1197 if (node != lowest)
1198 goto next;
1199
1200 mlog(ML_ERROR, "expected master %u died while "
1201 "this node was blocked waiting on it!\n",
1202 node);
1203 lowest = find_next_bit(mle->maybe_map,
1204 O2NM_MAX_NODES,
1205 lowest+1);
1206 if (lowest < O2NM_MAX_NODES) {
1207 mlog(0, "still blocked. waiting "
1208 "on %u now\n", lowest);
1209 goto next;
1210 }
1211
1212 /* mle is an MLE_BLOCK, but there is now
1213 * nothing left to block on. we need to return
1214 * all the way back out and try again with
1215 * an MLE_MASTER. dlm_do_local_recovery_cleanup
1216 * has already run, so the mle refcount is ok */
1217 mlog(0, "no longer blocking. we can "
1218 "try to master this here\n");
1219 mle->type = DLM_MLE_MASTER;
1220 memset(mle->maybe_map, 0,
1221 sizeof(mle->maybe_map));
1222 memset(mle->response_map, 0,
1223 sizeof(mle->maybe_map));
1224 memcpy(mle->vote_map, mle->node_map,
1225 sizeof(mle->node_map));
1226 mle->u.res = res;
1227 set_bit(dlm->node_num, mle->maybe_map);
1228
1229 ret = -EAGAIN;
1230 goto next;
1231 }
1232
1233 clear_bit(node, mle->maybe_map);
1234 if (node > dlm->node_num)
1235 goto next;
1236
1237 mlog(0, "dead node in map!\n");
1238 /* yuck. go back and re-contact all nodes
1239 * in the vote_map, removing this node. */
1240 memset(mle->response_map, 0,
1241 sizeof(mle->response_map));
1242 }
1243 ret = -EAGAIN;
1244next:
1245 node = dlm_bitmap_diff_iter_next(&bdi, &sc);
1246 }
1247 return ret;
1248}
1249
1250
1251/*
1252 * DLM_MASTER_REQUEST_MSG
1253 *
1254 * returns: 0 on success,
1255 * -errno on a network error
1256 *
1257 * on error, the caller should assume the target node is "dead"
1258 *
1259 */
1260
1261static int dlm_do_master_request(struct dlm_master_list_entry *mle, int to)
1262{
1263 struct dlm_ctxt *dlm = mle->dlm;
1264 struct dlm_master_request request;
1265 int ret, response=0, resend;
1266
1267 memset(&request, 0, sizeof(request));
1268 request.node_idx = dlm->node_num;
1269
1270 BUG_ON(mle->type == DLM_MLE_MIGRATION);
1271
1272 if (mle->type != DLM_MLE_MASTER) {
1273 request.namelen = mle->u.name.len;
1274 memcpy(request.name, mle->u.name.name, request.namelen);
1275 } else {
1276 request.namelen = mle->u.res->lockname.len;
1277 memcpy(request.name, mle->u.res->lockname.name,
1278 request.namelen);
1279 }
1280
1281again:
1282 ret = o2net_send_message(DLM_MASTER_REQUEST_MSG, dlm->key, &request,
1283 sizeof(request), to, &response);
1284 if (ret < 0) {
1285 if (ret == -ESRCH) {
1286 /* should never happen */
1287 mlog(ML_ERROR, "TCP stack not ready!\n");
1288 BUG();
1289 } else if (ret == -EINVAL) {
1290 mlog(ML_ERROR, "bad args passed to o2net!\n");
1291 BUG();
1292 } else if (ret == -ENOMEM) {
1293 mlog(ML_ERROR, "out of memory while trying to send "
1294 "network message! retrying\n");
1295 /* this is totally crude */
1296 msleep(50);
1297 goto again;
1298 } else if (!dlm_is_host_down(ret)) {
1299 /* not a network error. bad. */
1300 mlog_errno(ret);
1301 mlog(ML_ERROR, "unhandled error!");
1302 BUG();
1303 }
1304 /* all other errors should be network errors,
1305 * and likely indicate node death */
1306 mlog(ML_ERROR, "link to %d went down!\n", to);
1307 goto out;
1308 }
1309
1310 ret = 0;
1311 resend = 0;
1312 spin_lock(&mle->spinlock);
1313 switch (response) {
1314 case DLM_MASTER_RESP_YES:
1315 set_bit(to, mle->response_map);
1316 mlog(0, "node %u is the master, response=YES\n", to);
1317 mle->master = to;
1318 break;
1319 case DLM_MASTER_RESP_NO:
1320 mlog(0, "node %u not master, response=NO\n", to);
1321 set_bit(to, mle->response_map);
1322 break;
1323 case DLM_MASTER_RESP_MAYBE:
1324 mlog(0, "node %u not master, response=MAYBE\n", to);
1325 set_bit(to, mle->response_map);
1326 set_bit(to, mle->maybe_map);
1327 break;
1328 case DLM_MASTER_RESP_ERROR:
1329 mlog(0, "node %u hit an error, resending\n", to);
1330 resend = 1;
1331 response = 0;
1332 break;
1333 default:
1334 mlog(ML_ERROR, "bad response! %u\n", response);
1335 BUG();
1336 }
1337 spin_unlock(&mle->spinlock);
1338 if (resend) {
1339 /* this is also totally crude */
1340 msleep(50);
1341 goto again;
1342 }
1343
1344out:
1345 return ret;
1346}
1347
1348/*
1349 * locks that can be taken here:
1350 * dlm->spinlock
1351 * res->spinlock
1352 * mle->spinlock
1353 * dlm->master_list
1354 *
1355 * if possible, TRIM THIS DOWN!!!
1356 */
1357int dlm_master_request_handler(struct o2net_msg *msg, u32 len, void *data)
1358{
1359 u8 response = DLM_MASTER_RESP_MAYBE;
1360 struct dlm_ctxt *dlm = data;
9c6510a5 1361 struct dlm_lock_resource *res = NULL;
6714d8e8
KH		 1362 struct dlm_master_request *request = (struct dlm_master_request *) msg->buf;
1363 struct dlm_master_list_entry *mle = NULL, *tmpmle = NULL;
1364 char *name;
a3d33291 1365 unsigned int namelen, hash;
6714d8e8
KH		 1366 int found, ret;
1367 int set_maybe;
9c6510a5 1368 int dispatch_assert = 0;
6714d8e8
KH		 1369
1370 if (!dlm_grab(dlm))
1371 return DLM_MASTER_RESP_NO;
1372
1373 if (!dlm_domain_fully_joined(dlm)) {
1374 response = DLM_MASTER_RESP_NO;
1375 goto send_response;
1376 }
1377
1378 name = request->name;
1379 namelen = request->namelen;
a3d33291 1380 hash = dlm_lockid_hash(name, namelen);
6714d8e8
KH		 1381
1382 if (namelen > DLM_LOCKID_NAME_MAX) {
1383 response = DLM_IVBUFLEN;
1384 goto send_response;
1385 }
1386
1387way_up_top:
1388 spin_lock(&dlm->spinlock);
a3d33291 1389 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
6714d8e8
KH		 1390 if (res) {
1391 spin_unlock(&dlm->spinlock);
1392
1393 /* take care of the easy cases up front */
1394 spin_lock(&res->spinlock);
1395 if (res->state & DLM_LOCK_RES_RECOVERING) {
1396 spin_unlock(&res->spinlock);
1397 mlog(0, "returning DLM_MASTER_RESP_ERROR since res is "
1398 "being recovered\n");
1399 response = DLM_MASTER_RESP_ERROR;
1400 if (mle)
1401 kmem_cache_free(dlm_mle_cache, mle);
1402 goto send_response;
1403 }
1404
1405 if (res->owner == dlm->node_num) {
6714d8e8
KH		 1406 spin_unlock(&res->spinlock);
1407 // mlog(0, "this node is the master\n");
1408 response = DLM_MASTER_RESP_YES;
1409 if (mle)
1410 kmem_cache_free(dlm_mle_cache, mle);
1411
1412 /* this node is the owner.
1413 * there is some extra work that needs to
1414 * happen now. the requesting node has
1415 * caused all nodes up to this one to
1416 * create mles. this node now needs to
1417 * go back and clean those up. */
9c6510a5 1418 dispatch_assert = 1;
6714d8e8
KH		 1419 goto send_response;
1420 } else if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1421 spin_unlock(&res->spinlock);
1422 // mlog(0, "node %u is the master\n", res->owner);
1423 response = DLM_MASTER_RESP_NO;
1424 if (mle)
1425 kmem_cache_free(dlm_mle_cache, mle);
1426 goto send_response;
1427 }
1428
1429 /* ok, there is no owner. either this node is
1430 * being blocked, or it is actively trying to
1431 * master this lock. */
1432 if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
1433 mlog(ML_ERROR, "lock with no owner should be "
1434 "in-progress!\n");
1435 BUG();
1436 }
1437
1438 // mlog(0, "lockres is in progress...\n");
1439 spin_lock(&dlm->master_lock);
1440 found = dlm_find_mle(dlm, &tmpmle, name, namelen);
1441 if (!found) {
1442 mlog(ML_ERROR, "no mle found for this lock!\n");
1443 BUG();
1444 }
1445 set_maybe = 1;
1446 spin_lock(&tmpmle->spinlock);
1447 if (tmpmle->type == DLM_MLE_BLOCK) {
1448 // mlog(0, "this node is waiting for "
1449 // "lockres to be mastered\n");
1450 response = DLM_MASTER_RESP_NO;
1451 } else if (tmpmle->type == DLM_MLE_MIGRATION) {
1452 mlog(0, "node %u is master, but trying to migrate to "
1453 "node %u.\n", tmpmle->master, tmpmle->new_master);
1454 if (tmpmle->master == dlm->node_num) {
1455 response = DLM_MASTER_RESP_YES;
1456 mlog(ML_ERROR, "no owner on lockres, but this "
1457 "node is trying to migrate it to %u?!\n",
1458 tmpmle->new_master);
1459 BUG();
1460 } else {
1461 /* the real master can respond on its own */
1462 response = DLM_MASTER_RESP_NO;
1463 }
1464 } else if (tmpmle->master != DLM_LOCK_RES_OWNER_UNKNOWN) {
1465 set_maybe = 0;
9c6510a5 1466 if (tmpmle->master == dlm->node_num) {
6714d8e8 1467 response = DLM_MASTER_RESP_YES;
9c6510a5
KH		 1468 /* this node will be the owner.
1469 * go back and clean the mles on any
1470 * other nodes */
1471 dispatch_assert = 1;
1472 } else
6714d8e8
KH		 1473 response = DLM_MASTER_RESP_NO;
1474 } else {
1475 // mlog(0, "this node is attempting to "
1476 // "master lockres\n");
1477 response = DLM_MASTER_RESP_MAYBE;
1478 }
1479 if (set_maybe)
1480 set_bit(request->node_idx, tmpmle->maybe_map);
1481 spin_unlock(&tmpmle->spinlock);
1482
1483 spin_unlock(&dlm->master_lock);
1484 spin_unlock(&res->spinlock);
1485
1486 /* keep the mle attached to heartbeat events */
1487 dlm_put_mle(tmpmle);
1488 if (mle)
1489 kmem_cache_free(dlm_mle_cache, mle);
1490 goto send_response;
1491 }
1492
1493 /*
1494 * lockres doesn't exist on this node
1495 * if there is an MLE_BLOCK, return NO
1496 * if there is an MLE_MASTER, return MAYBE
1497 * otherwise, add an MLE_BLOCK, return NO
1498 */
1499 spin_lock(&dlm->master_lock);
1500 found = dlm_find_mle(dlm, &tmpmle, name, namelen);
1501 if (!found) {
1502 /* this lockid has never been seen on this node yet */
1503 // mlog(0, "no mle found\n");
1504 if (!mle) {
1505 spin_unlock(&dlm->master_lock);
1506 spin_unlock(&dlm->spinlock);
1507
1508 mle = (struct dlm_master_list_entry *)
1509 kmem_cache_alloc(dlm_mle_cache, GFP_KERNEL);
1510 if (!mle) {
6714d8e8 1511 response = DLM_MASTER_RESP_ERROR;
9c6510a5 1512 mlog_errno(-ENOMEM);
6714d8e8
KH		 1513 goto send_response;
1514 }
1515 spin_lock(&dlm->spinlock);
1516 dlm_init_mle(mle, DLM_MLE_BLOCK, dlm, NULL,
1517 name, namelen);
1518 spin_unlock(&dlm->spinlock);
1519 goto way_up_top;
1520 }
1521
1522 // mlog(0, "this is second time thru, already allocated, "
1523 // "add the block.\n");
1524 set_bit(request->node_idx, mle->maybe_map);
1525 list_add(&mle->list, &dlm->master_list);
1526 response = DLM_MASTER_RESP_NO;
1527 } else {
1528 // mlog(0, "mle was found\n");
1529 set_maybe = 1;
1530 spin_lock(&tmpmle->spinlock);
9c6510a5
KH		 1531 if (tmpmle->master == dlm->node_num) {
1532 mlog(ML_ERROR, "no lockres, but an mle with this node as master!\n");
1533 BUG();
1534 }
6714d8e8
KH		 1535 if (tmpmle->type == DLM_MLE_BLOCK)
1536 response = DLM_MASTER_RESP_NO;
1537 else if (tmpmle->type == DLM_MLE_MIGRATION) {
1538 mlog(0, "migration mle was found (%u->%u)\n",
1539 tmpmle->master, tmpmle->new_master);
6714d8e8
KH		 1540 /* real master can respond on its own */
1541 response = DLM_MASTER_RESP_NO;
9c6510a5
KH		 1542 } else
1543 response = DLM_MASTER_RESP_MAYBE;
6714d8e8
KH		 1544 if (set_maybe)
1545 set_bit(request->node_idx, tmpmle->maybe_map);
1546 spin_unlock(&tmpmle->spinlock);
1547 }
1548 spin_unlock(&dlm->master_lock);
1549 spin_unlock(&dlm->spinlock);
1550
1551 if (found) {
1552 /* keep the mle attached to heartbeat events */
1553 dlm_put_mle(tmpmle);
1554 }
1555send_response:
9c6510a5
KH		 1556
1557 if (dispatch_assert) {
1558 if (response != DLM_MASTER_RESP_YES)
1559 mlog(ML_ERROR, "invalid response %d\n", response);
1560 if (!res) {
1561 mlog(ML_ERROR, "bad lockres while trying to assert!\n");
1562 BUG();
1563 }
1564 mlog(0, "%u is the owner of %.*s, cleaning everyone else\n",
1565 dlm->node_num, res->lockname.len, res->lockname.name);
1566 ret = dlm_dispatch_assert_master(dlm, res, 0, request->node_idx,
1567 DLM_ASSERT_MASTER_MLE_CLEANUP);
1568 if (ret < 0) {
1569 mlog(ML_ERROR, "failed to dispatch assert master work\n");
1570 response = DLM_MASTER_RESP_ERROR;
1571 }
1572 }
1573
6714d8e8
KH		 1574 dlm_put(dlm);
1575 return response;
1576}
1577
1578/*
1579 * DLM_ASSERT_MASTER_MSG
1580 */
1581
1582
1583/*
1584 * NOTE: this can be used for debugging
1585 * can periodically run all locks owned by this node
1586 * and re-assert across the cluster...
1587 */
1588static int dlm_do_assert_master(struct dlm_ctxt *dlm, const char *lockname,
1589 unsigned int namelen, void *nodemap,
1590 u32 flags)
1591{
1592 struct dlm_assert_master assert;
1593 int to, tmpret;
1594 struct dlm_node_iter iter;
1595 int ret = 0;
9c6510a5 1596 int reassert;
6714d8e8
KH		 1597
1598 BUG_ON(namelen > O2NM_MAX_NAME_LEN);
9c6510a5
KH		 1599again:
1600 reassert = 0;
6714d8e8
KH		 1601
1602 /* note that if this nodemap is empty, it returns 0 */
1603 dlm_node_iter_init(nodemap, &iter);
1604 while ((to = dlm_node_iter_next(&iter)) >= 0) {
1605 int r = 0;
1606 mlog(0, "sending assert master to %d (%.*s)\n", to,
1607 namelen, lockname);
1608 memset(&assert, 0, sizeof(assert));
1609 assert.node_idx = dlm->node_num;
1610 assert.namelen = namelen;
1611 memcpy(assert.name, lockname, namelen);
1612 assert.flags = cpu_to_be32(flags);
1613
1614 tmpret = o2net_send_message(DLM_ASSERT_MASTER_MSG, dlm->key,
1615 &assert, sizeof(assert), to, &r);
1616 if (tmpret < 0) {
1617 mlog(ML_ERROR, "assert_master returned %d!\n", tmpret);
1618 if (!dlm_is_host_down(tmpret)) {
1619 mlog(ML_ERROR, "unhandled error!\n");
1620 BUG();
1621 }
1622 /* a node died. finish out the rest of the nodes. */
1623 mlog(ML_ERROR, "link to %d went down!\n", to);
1624 /* any nonzero status return will do */
1625 ret = tmpret;
1626 } else if (r < 0) {
1627 /* ok, something horribly messed. kill thyself. */
1628 mlog(ML_ERROR,"during assert master of %.*s to %u, "
1629 "got %d.\n", namelen, lockname, to, r);
1630 dlm_dump_lock_resources(dlm);
1631 BUG();
9c6510a5
KH		 1632 } else if (r == EAGAIN) {
1633 mlog(0, "%.*s: node %u create mles on other "
1634 "nodes and requests a re-assert\n",
1635 namelen, lockname, to);
1636 reassert = 1;
6714d8e8
KH		 1637 }
1638 }
1639
9c6510a5
KH		 1640 if (reassert)
1641 goto again;
1642
6714d8e8
KH		 1643 return ret;
1644}
1645
1646/*
1647 * locks that can be taken here:
1648 * dlm->spinlock
1649 * res->spinlock
1650 * mle->spinlock
1651 * dlm->master_list
1652 *
1653 * if possible, TRIM THIS DOWN!!!
1654 */
1655int dlm_assert_master_handler(struct o2net_msg *msg, u32 len, void *data)
1656{
1657 struct dlm_ctxt *dlm = data;
1658 struct dlm_master_list_entry *mle = NULL;
1659 struct dlm_assert_master *assert = (struct dlm_assert_master *)msg->buf;
1660 struct dlm_lock_resource *res = NULL;
1661 char *name;
a3d33291 1662 unsigned int namelen, hash;
6714d8e8 1663 u32 flags;
9c6510a5
KH		 1664 int master_request = 0;
1665 int ret = 0;
6714d8e8
KH		 1666
1667 if (!dlm_grab(dlm))
1668 return 0;
1669
1670 name = assert->name;
1671 namelen = assert->namelen;
a3d33291 1672 hash = dlm_lockid_hash(name, namelen);
6714d8e8
KH		 1673 flags = be32_to_cpu(assert->flags);
1674
1675 if (namelen > DLM_LOCKID_NAME_MAX) {
1676 mlog(ML_ERROR, "Invalid name length!");
1677 goto done;
1678 }
1679
1680 spin_lock(&dlm->spinlock);
1681
1682 if (flags)
1683 mlog(0, "assert_master with flags: %u\n", flags);
1684
1685 /* find the MLE */
1686 spin_lock(&dlm->master_lock);
1687 if (!dlm_find_mle(dlm, &mle, name, namelen)) {
1688 /* not an error, could be master just re-asserting */
1689 mlog(0, "just got an assert_master from %u, but no "
1690 "MLE for it! (%.*s)\n", assert->node_idx,
1691 namelen, name);
1692 } else {
1693 int bit = find_next_bit (mle->maybe_map, O2NM_MAX_NODES, 0);
1694 if (bit >= O2NM_MAX_NODES) {
1695 /* not necessarily an error, though less likely.
1696 * could be master just re-asserting. */
1697 mlog(ML_ERROR, "no bits set in the maybe_map, but %u "
1698 "is asserting! (%.*s)\n", assert->node_idx,
1699 namelen, name);
1700 } else if (bit != assert->node_idx) {
1701 if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
1702 mlog(0, "master %u was found, %u should "
1703 "back off\n", assert->node_idx, bit);
1704 } else {
1705 /* with the fix for bug 569, a higher node
1706 * number winning the mastery will respond
1707 * YES to mastery requests, but this node
1708 * had no way of knowing. let it pass. */
1709 mlog(ML_ERROR, "%u is the lowest node, "
1710 "%u is asserting. (%.*s) %u must "
1711 "have begun after %u won.\n", bit,
1712 assert->node_idx, namelen, name, bit,
1713 assert->node_idx);
1714 }
1715 }
1716 }
1717 spin_unlock(&dlm->master_lock);
1718
1719 /* ok everything checks out with the MLE
1720 * now check to see if there is a lockres */
a3d33291 1721 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
6714d8e8
KH		 1722 if (res) {
1723 spin_lock(&res->spinlock);
1724 if (res->state & DLM_LOCK_RES_RECOVERING) {
1725 mlog(ML_ERROR, "%u asserting but %.*s is "
1726 "RECOVERING!\n", assert->node_idx, namelen, name);
1727 goto kill;
1728 }
1729 if (!mle) {
1730 if (res->owner != assert->node_idx) {
1731 mlog(ML_ERROR, "assert_master from "
1732 "%u, but current owner is "
1733 "%u! (%.*s)\n",
1734 assert->node_idx, res->owner,
1735 namelen, name);
1736 goto kill;
1737 }
1738 } else if (mle->type != DLM_MLE_MIGRATION) {
1739 if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1740 /* owner is just re-asserting */
1741 if (res->owner == assert->node_idx) {
1742 mlog(0, "owner %u re-asserting on "
1743 "lock %.*s\n", assert->node_idx,
1744 namelen, name);
1745 goto ok;
1746 }
1747 mlog(ML_ERROR, "got assert_master from "
1748 "node %u, but %u is the owner! "
1749 "(%.*s)\n", assert->node_idx,
1750 res->owner, namelen, name);
1751 goto kill;
1752 }
1753 if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
1754 mlog(ML_ERROR, "got assert from %u, but lock "
1755 "with no owner should be "
1756 "in-progress! (%.*s)\n",
1757 assert->node_idx,
1758 namelen, name);
1759 goto kill;
1760 }
1761 } else /* mle->type == DLM_MLE_MIGRATION */ {
1762 /* should only be getting an assert from new master */
1763 if (assert->node_idx != mle->new_master) {
1764 mlog(ML_ERROR, "got assert from %u, but "
1765 "new master is %u, and old master "
1766 "was %u (%.*s)\n",
1767 assert->node_idx, mle->new_master,
1768 mle->master, namelen, name);
1769 goto kill;
1770 }
1771
1772 }
1773ok:
1774 spin_unlock(&res->spinlock);
1775 }
1776 spin_unlock(&dlm->spinlock);
1777
1778 // mlog(0, "woo! got an assert_master from node %u!\n",
1779 // assert->node_idx);
1780 if (mle) {
9c6510a5
KH		 1781 int extra_ref = 0;
1782 int nn = -1;
a2bf0477 1783 int rr, err = 0;
6714d8e8
KH		 1784
1785 spin_lock(&mle->spinlock);
9c6510a5
KH		 1786 if (mle->type == DLM_MLE_BLOCK || mle->type == DLM_MLE_MIGRATION)
1787 extra_ref = 1;
1788 else {
1789 /* MASTER mle: if any bits set in the response map
1790 * then the calling node needs to re-assert to clear
1791 * up nodes that this node contacted */
1792 while ((nn = find_next_bit (mle->response_map, O2NM_MAX_NODES,
1793 nn+1)) < O2NM_MAX_NODES) {
1794 if (nn != dlm->node_num && nn != assert->node_idx)
1795 master_request = 1;
1796 }
1797 }
6714d8e8
KH		 1798 mle->master = assert->node_idx;
1799 atomic_set(&mle->woken, 1);
1800 wake_up(&mle->wq);
1801 spin_unlock(&mle->spinlock);
1802
a2bf0477 1803 if (res) {
6714d8e8 1804 spin_lock(&res->spinlock);
a2bf0477
KH		 1805 if (mle->type == DLM_MLE_MIGRATION) {
1806 mlog(0, "finishing off migration of lockres %.*s, "
1807 "from %u to %u\n",
1808 res->lockname.len, res->lockname.name,
1809 dlm->node_num, mle->new_master);
1810 res->state &= ~DLM_LOCK_RES_MIGRATING;
1811 dlm_change_lockres_owner(dlm, res, mle->new_master);
1812 BUG_ON(res->state & DLM_LOCK_RES_DIRTY);
1813 } else {
1814 dlm_change_lockres_owner(dlm, res, mle->master);
1815 }
6714d8e8
KH		 1816 spin_unlock(&res->spinlock);
1817 }
a2bf0477
KH		 1818
1819 /* master is known, detach if not already detached.
1820 * ensures that only one assert_master call will happen
1821 * on this mle. */
1822 spin_lock(&dlm->spinlock);
1823 spin_lock(&dlm->master_lock);
1824
1825 rr = atomic_read(&mle->mle_refs.refcount);
1826 if (mle->inuse > 0) {
1827 if (extra_ref && rr < 3)
1828 err = 1;
1829 else if (!extra_ref && rr < 2)
1830 err = 1;
1831 } else {
1832 if (extra_ref && rr < 2)
1833 err = 1;
1834 else if (!extra_ref && rr < 1)
1835 err = 1;
1836 }
1837 if (err) {
1838 mlog(ML_ERROR, "%s:%.*s: got assert master from %u "
1839 "that will mess up this node, refs=%d, extra=%d, "
1840 "inuse=%d\n", dlm->name, namelen, name,
1841 assert->node_idx, rr, extra_ref, mle->inuse);
1842 dlm_print_one_mle(mle);
1843 }
1844 list_del_init(&mle->list);
1845 __dlm_mle_detach_hb_events(dlm, mle);
1846 __dlm_put_mle(mle);
6714d8e8
KH		 1847 if (extra_ref) {
1848 /* the assert master message now balances the extra
1849 * ref given by the master / migration request message.
1850 * if this is the last put, it will be removed
1851 * from the list. */
a2bf0477
KH		 1852 __dlm_put_mle(mle);
1853 }
1854 spin_unlock(&dlm->master_lock);
1855 spin_unlock(&dlm->spinlock);
1856 } else if (res) {
1857 if (res->owner != assert->node_idx) {
1858 mlog(0, "assert_master from %u, but current "
1859 "owner is %u (%.*s), no mle\n", assert->node_idx,
1860 res->owner, namelen, name);
6714d8e8
KH		 1861 }
1862 }
1863
1864done:
9c6510a5 1865 ret = 0;
6714d8e8
KH		 1866 if (res)
1867 dlm_lockres_put(res);
1868 dlm_put(dlm);
9c6510a5
KH		 1869 if (master_request) {
1870 mlog(0, "need to tell master to reassert\n");
1871 ret = EAGAIN; // positive. negative would shoot down the node.
1872 }
1873 return ret;
6714d8e8
KH		 1874
1875kill:
1876 /* kill the caller! */
1877 spin_unlock(&res->spinlock);
1878 spin_unlock(&dlm->spinlock);
1879 dlm_lockres_put(res);
1880 mlog(ML_ERROR, "Bad message received from another node. Dumping state "
1881 "and killing the other node now! This node is OK and can continue.\n");
1882 dlm_dump_lock_resources(dlm);
1883 dlm_put(dlm);
1884 return -EINVAL;
1885}
1886
1887int dlm_dispatch_assert_master(struct dlm_ctxt *dlm,
1888 struct dlm_lock_resource *res,
1889 int ignore_higher, u8 request_from, u32 flags)
1890{
1891 struct dlm_work_item *item;
1892 item = kcalloc(1, sizeof(*item), GFP_KERNEL);
1893 if (!item)
1894 return -ENOMEM;
1895
1896
1897 /* queue up work for dlm_assert_master_worker */
1898 dlm_grab(dlm); /* get an extra ref for the work item */
1899 dlm_init_work_item(dlm, item, dlm_assert_master_worker, NULL);
1900 item->u.am.lockres = res; /* already have a ref */
1901 /* can optionally ignore node numbers higher than this node */
1902 item->u.am.ignore_higher = ignore_higher;
1903 item->u.am.request_from = request_from;
1904 item->u.am.flags = flags;
1905
9c6510a5
KH		 1906 if (ignore_higher)
1907 mlog(0, "IGNORE HIGHER: %.*s\n", res->lockname.len,
1908 res->lockname.name);
1909
6714d8e8
KH		 1910 spin_lock(&dlm->work_lock);
1911 list_add_tail(&item->list, &dlm->work_list);
1912 spin_unlock(&dlm->work_lock);
1913
1914 schedule_work(&dlm->dispatched_work);
1915 return 0;
1916}
1917
1918static void dlm_assert_master_worker(struct dlm_work_item *item, void *data)
1919{
1920 struct dlm_ctxt *dlm = data;
1921 int ret = 0;
1922 struct dlm_lock_resource *res;
1923 unsigned long nodemap[BITS_TO_LONGS(O2NM_MAX_NODES)];
1924 int ignore_higher;
1925 int bit;
1926 u8 request_from;
1927 u32 flags;
1928
1929 dlm = item->dlm;
1930 res = item->u.am.lockres;
1931 ignore_higher = item->u.am.ignore_higher;
1932 request_from = item->u.am.request_from;
1933 flags = item->u.am.flags;
1934
1935 spin_lock(&dlm->spinlock);
1936 memcpy(nodemap, dlm->domain_map, sizeof(nodemap));
1937 spin_unlock(&dlm->spinlock);
1938
1939 clear_bit(dlm->node_num, nodemap);
1940 if (ignore_higher) {
1941 /* if is this just to clear up mles for nodes below
1942 * this node, do not send the message to the original
1943 * caller or any node number higher than this */
1944 clear_bit(request_from, nodemap);
1945 bit = dlm->node_num;
1946 while (1) {
1947 bit = find_next_bit(nodemap, O2NM_MAX_NODES,
1948 bit+1);
1949 if (bit >= O2NM_MAX_NODES)
1950 break;
1951 clear_bit(bit, nodemap);
1952 }
1953 }
1954
1955 /* this call now finishes out the nodemap
1956 * even if one or more nodes die */
1957 mlog(0, "worker about to master %.*s here, this=%u\n",
1958 res->lockname.len, res->lockname.name, dlm->node_num);
1959 ret = dlm_do_assert_master(dlm, res->lockname.name,
1960 res->lockname.len,
1961 nodemap, flags);
1962 if (ret < 0) {
1963 /* no need to restart, we are done */
1964 mlog_errno(ret);
1965 }
1966
1967 dlm_lockres_put(res);
1968
1969 mlog(0, "finished with dlm_assert_master_worker\n");
1970}
1971
c03872f5
KH		 1972/* SPECIAL CASE for the $RECOVERY lock used by the recovery thread.
1973 * We cannot wait for node recovery to complete to begin mastering this
1974 * lockres because this lockres is used to kick off recovery! ;-)
1975 * So, do a pre-check on all living nodes to see if any of those nodes
1976 * think that $RECOVERY is currently mastered by a dead node. If so,
1977 * we wait a short time to allow that node to get notified by its own
1978 * heartbeat stack, then check again. All $RECOVERY lock resources
1979 * mastered by dead nodes are purged when the hearbeat callback is
1980 * fired, so we can know for sure that it is safe to continue once
1981 * the node returns a live node or no node. */
1982static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
1983 struct dlm_lock_resource *res)
1984{
1985 struct dlm_node_iter iter;
1986 int nodenum;
1987 int ret = 0;
1988 u8 master = DLM_LOCK_RES_OWNER_UNKNOWN;
1989
1990 spin_lock(&dlm->spinlock);
1991 dlm_node_iter_init(dlm->domain_map, &iter);
1992 spin_unlock(&dlm->spinlock);
1993
1994 while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
1995 /* do not send to self */
1996 if (nodenum == dlm->node_num)
1997 continue;
1998 ret = dlm_do_master_requery(dlm, res, nodenum, &master);
1999 if (ret < 0) {
2000 mlog_errno(ret);
2001 if (!dlm_is_host_down(ret))
2002 BUG();
2003 /* host is down, so answer for that node would be
2004 * DLM_LOCK_RES_OWNER_UNKNOWN. continue. */
2005 }
2006
2007 if (master != DLM_LOCK_RES_OWNER_UNKNOWN) {
2008 /* check to see if this master is in the recovery map */
2009 spin_lock(&dlm->spinlock);
2010 if (test_bit(master, dlm->recovery_map)) {
2011 mlog(ML_NOTICE, "%s: node %u has not seen "
2012 "node %u go down yet, and thinks the "
2013 "dead node is mastering the recovery "
2014 "lock. must wait.\n", dlm->name,
2015 nodenum, master);
2016 ret = -EAGAIN;
2017 }
2018 spin_unlock(&dlm->spinlock);
2019 mlog(0, "%s: reco lock master is %u\n", dlm->name,
2020 master);
2021 break;
2022 }
2023 }
2024 return ret;
2025}
2026
6714d8e8
KH		 2027
2028/*
2029 * DLM_MIGRATE_LOCKRES
2030 */
2031
2032
2033int dlm_migrate_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
2034 u8 target)
2035{
2036 struct dlm_master_list_entry *mle = NULL;
2037 struct dlm_master_list_entry *oldmle = NULL;
2038 struct dlm_migratable_lockres *mres = NULL;
2039 int ret = -EINVAL;
2040 const char *name;
2041 unsigned int namelen;
2042 int mle_added = 0;
2043 struct list_head *queue, *iter;
2044 int i;
2045 struct dlm_lock *lock;
2046 int empty = 1;
2047
2048 if (!dlm_grab(dlm))
2049 return -EINVAL;
2050
2051 name = res->lockname.name;
2052 namelen = res->lockname.len;
2053
2054 mlog(0, "migrating %.*s to %u\n", namelen, name, target);
2055
2056 /*
2057 * ensure this lockres is a proper candidate for migration
2058 */
2059 spin_lock(&res->spinlock);
2060 if (res->owner == DLM_LOCK_RES_OWNER_UNKNOWN) {
2061 mlog(0, "cannot migrate lockres with unknown owner!\n");
2062 spin_unlock(&res->spinlock);
2063 goto leave;
2064 }
2065 if (res->owner != dlm->node_num) {
2066 mlog(0, "cannot migrate lockres this node doesn't own!\n");
2067 spin_unlock(&res->spinlock);
2068 goto leave;
2069 }
2070 mlog(0, "checking queues...\n");
2071 queue = &res->granted;
2072 for (i=0; i<3; i++) {
2073 list_for_each(iter, queue) {
2074 lock = list_entry (iter, struct dlm_lock, list);
2075 empty = 0;
2076 if (lock->ml.node == dlm->node_num) {
2077 mlog(0, "found a lock owned by this node "
2078 "still on the %s queue! will not "
2079 "migrate this lockres\n",
2080 i==0 ? "granted" :
2081 (i==1 ? "converting" : "blocked"));
2082 spin_unlock(&res->spinlock);
2083 ret = -ENOTEMPTY;
2084 goto leave;
2085 }
2086 }
2087 queue++;
2088 }
2089 mlog(0, "all locks on this lockres are nonlocal. continuing\n");
2090 spin_unlock(&res->spinlock);
2091
2092 /* no work to do */
2093 if (empty) {
2094 mlog(0, "no locks were found on this lockres! done!\n");
2095 ret = 0;
2096 goto leave;
2097 }
2098
2099 /*
2100 * preallocate up front
2101 * if this fails, abort
2102 */
2103
2104 ret = -ENOMEM;
2105 mres = (struct dlm_migratable_lockres *) __get_free_page(GFP_KERNEL);
2106 if (!mres) {
2107 mlog_errno(ret);
2108 goto leave;
2109 }
2110
2111 mle = (struct dlm_master_list_entry *) kmem_cache_alloc(dlm_mle_cache,
2112 GFP_KERNEL);
2113 if (!mle) {
2114 mlog_errno(ret);
2115 goto leave;
2116 }
2117 ret = 0;
2118
2119 /*
2120 * find a node to migrate the lockres to
2121 */
2122
2123 mlog(0, "picking a migration node\n");
2124 spin_lock(&dlm->spinlock);
2125 /* pick a new node */
2126 if (!test_bit(target, dlm->domain_map) ||
2127 target >= O2NM_MAX_NODES) {
2128 target = dlm_pick_migration_target(dlm, res);
2129 }
2130 mlog(0, "node %u chosen for migration\n", target);
2131
2132 if (target >= O2NM_MAX_NODES ||
2133 !test_bit(target, dlm->domain_map)) {
2134 /* target chosen is not alive */
2135 ret = -EINVAL;
2136 }
2137
2138 if (ret) {
2139 spin_unlock(&dlm->spinlock);
2140 goto fail;
2141 }
2142
2143 mlog(0, "continuing with target = %u\n", target);
2144
2145 /*
2146 * clear any existing master requests and
2147 * add the migration mle to the list
2148 */
2149 spin_lock(&dlm->master_lock);
2150 ret = dlm_add_migration_mle(dlm, res, mle, &oldmle, name,
2151 namelen, target, dlm->node_num);
2152 spin_unlock(&dlm->master_lock);
2153 spin_unlock(&dlm->spinlock);
2154
2155 if (ret == -EEXIST) {
2156 mlog(0, "another process is already migrating it\n");
2157 goto fail;
2158 }
2159 mle_added = 1;
2160
2161 /*
2162 * set the MIGRATING flag and flush asts
2163 * if we fail after this we need to re-dirty the lockres
2164 */
2165 if (dlm_mark_lockres_migrating(dlm, res, target) < 0) {
2166 mlog(ML_ERROR, "tried to migrate %.*s to %u, but "
2167 "the target went down.\n", res->lockname.len,
2168 res->lockname.name, target);
2169 spin_lock(&res->spinlock);
2170 res->state &= ~DLM_LOCK_RES_MIGRATING;
2171 spin_unlock(&res->spinlock);
2172 ret = -EINVAL;
2173 }
2174
2175fail:
2176 if (oldmle) {
2177 /* master is known, detach if not already detached */
2178 dlm_mle_detach_hb_events(dlm, oldmle);
2179 dlm_put_mle(oldmle);
2180 }
2181
2182 if (ret < 0) {
2183 if (mle_added) {
2184 dlm_mle_detach_hb_events(dlm, mle);
2185 dlm_put_mle(mle);
2186 } else if (mle) {
2187 kmem_cache_free(dlm_mle_cache, mle);
2188 }
2189 goto leave;
2190 }
2191
2192 /*
2193 * at this point, we have a migration target, an mle
2194 * in the master list, and the MIGRATING flag set on
2195 * the lockres
2196 */
2197
2198
2199 /* get an extra reference on the mle.
2200 * otherwise the assert_master from the new
2201 * master will destroy this.
2202 * also, make sure that all callers of dlm_get_mle
2203 * take both dlm->spinlock and dlm->master_lock */
2204 spin_lock(&dlm->spinlock);
2205 spin_lock(&dlm->master_lock);
a2bf0477 2206 dlm_get_mle_inuse(mle);
6714d8e8
KH		 2207 spin_unlock(&dlm->master_lock);
2208 spin_unlock(&dlm->spinlock);
2209
2210 /* notify new node and send all lock state */
2211 /* call send_one_lockres with migration flag.
2212 * this serves as notice to the target node that a
2213 * migration is starting. */
2214 ret = dlm_send_one_lockres(dlm, res, mres, target,
2215 DLM_MRES_MIGRATION);
2216
2217 if (ret < 0) {
2218 mlog(0, "migration to node %u failed with %d\n",
2219 target, ret);
2220 /* migration failed, detach and clean up mle */
2221 dlm_mle_detach_hb_events(dlm, mle);
2222 dlm_put_mle(mle);
a2bf0477
KH		 2223 dlm_put_mle_inuse(mle);
2224 spin_lock(&res->spinlock);
2225 res->state &= ~DLM_LOCK_RES_MIGRATING;
2226 spin_unlock(&res->spinlock);
6714d8e8
KH		 2227 goto leave;
2228 }
2229
2230 /* at this point, the target sends a message to all nodes,
2231 * (using dlm_do_migrate_request). this node is skipped since
2232 * we had to put an mle in the list to begin the process. this
2233 * node now waits for target to do an assert master. this node
2234 * will be the last one notified, ensuring that the migration
2235 * is complete everywhere. if the target dies while this is
2236 * going on, some nodes could potentially see the target as the
2237 * master, so it is important that my recovery finds the migration
2238 * mle and sets the master to UNKNONWN. */
2239
2240
2241 /* wait for new node to assert master */
2242 while (1) {
2243 ret = wait_event_interruptible_timeout(mle->wq,
2244 (atomic_read(&mle->woken) == 1),
2245 msecs_to_jiffies(5000));
2246
2247 if (ret >= 0) {
2248 if (atomic_read(&mle->woken) == 1 ||
2249 res->owner == target)
2250 break;
2251
2252 mlog(0, "timed out during migration\n");
e2faea4c
KH		 2253 /* avoid hang during shutdown when migrating lockres
2254 * to a node which also goes down */
2255 if (dlm_is_node_dead(dlm, target)) {
2256 mlog(0, "%s:%.*s: expected migration target %u "
2257 "is no longer up. restarting.\n",
2258 dlm->name, res->lockname.len,
2259 res->lockname.name, target);
2260 ret = -ERESTARTSYS;
2261 }
6714d8e8
KH		 2262 }
2263 if (ret == -ERESTARTSYS) {
2264 /* migration failed, detach and clean up mle */
2265 dlm_mle_detach_hb_events(dlm, mle);
2266 dlm_put_mle(mle);
a2bf0477
KH		 2267 dlm_put_mle_inuse(mle);
2268 spin_lock(&res->spinlock);
2269 res->state &= ~DLM_LOCK_RES_MIGRATING;
2270 spin_unlock(&res->spinlock);
6714d8e8
KH		 2271 goto leave;
2272 }
2273 /* TODO: if node died: stop, clean up, return error */
2274 }
2275
2276 /* all done, set the owner, clear the flag */
2277 spin_lock(&res->spinlock);
2278 dlm_set_lockres_owner(dlm, res, target);
2279 res->state &= ~DLM_LOCK_RES_MIGRATING;
2280 dlm_remove_nonlocal_locks(dlm, res);
2281 spin_unlock(&res->spinlock);
2282 wake_up(&res->wq);
2283
2284 /* master is known, detach if not already detached */
2285 dlm_mle_detach_hb_events(dlm, mle);
a2bf0477 2286 dlm_put_mle_inuse(mle);
6714d8e8
KH		 2287 ret = 0;
2288
2289 dlm_lockres_calc_usage(dlm, res);
2290
2291leave:
2292 /* re-dirty the lockres if we failed */
2293 if (ret < 0)
2294 dlm_kick_thread(dlm, res);
2295
2296 /* TODO: cleanup */
2297 if (mres)
2298 free_page((unsigned long)mres);
2299
2300 dlm_put(dlm);
2301
2302 mlog(0, "returning %d\n", ret);
2303 return ret;
2304}
2305EXPORT_SYMBOL_GPL(dlm_migrate_lockres);
2306
2307int dlm_lock_basts_flushed(struct dlm_ctxt *dlm, struct dlm_lock *lock)
2308{
2309 int ret;
2310 spin_lock(&dlm->ast_lock);
2311 spin_lock(&lock->spinlock);
2312 ret = (list_empty(&lock->bast_list) && !lock->bast_pending);
2313 spin_unlock(&lock->spinlock);
2314 spin_unlock(&dlm->ast_lock);
2315 return ret;
2316}
2317
2318static int dlm_migration_can_proceed(struct dlm_ctxt *dlm,
2319 struct dlm_lock_resource *res,
2320 u8 mig_target)
2321{
2322 int can_proceed;
2323 spin_lock(&res->spinlock);
2324 can_proceed = !!(res->state & DLM_LOCK_RES_MIGRATING);
2325 spin_unlock(&res->spinlock);
2326
2327 /* target has died, so make the caller break out of the
2328 * wait_event, but caller must recheck the domain_map */
2329 spin_lock(&dlm->spinlock);
2330 if (!test_bit(mig_target, dlm->domain_map))
2331 can_proceed = 1;
2332 spin_unlock(&dlm->spinlock);
2333 return can_proceed;
2334}
2335
2336int dlm_lockres_is_dirty(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
2337{
2338 int ret;
2339 spin_lock(&res->spinlock);
2340 ret = !!(res->state & DLM_LOCK_RES_DIRTY);
2341 spin_unlock(&res->spinlock);
2342 return ret;
2343}
2344
2345
2346static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
2347 struct dlm_lock_resource *res,
2348 u8 target)
2349{
2350 int ret = 0;
2351
2352 mlog(0, "dlm_mark_lockres_migrating: %.*s, from %u to %u\n",
2353 res->lockname.len, res->lockname.name, dlm->node_num,
2354 target);
2355 /* need to set MIGRATING flag on lockres. this is done by
2356 * ensuring that all asts have been flushed for this lockres. */
2357 spin_lock(&res->spinlock);
2358 BUG_ON(res->migration_pending);
2359 res->migration_pending = 1;
2360 /* strategy is to reserve an extra ast then release
2361 * it below, letting the release do all of the work */
2362 __dlm_lockres_reserve_ast(res);
2363 spin_unlock(&res->spinlock);
2364
2365 /* now flush all the pending asts.. hang out for a bit */
2366 dlm_kick_thread(dlm, res);
2367 wait_event(dlm->ast_wq, !dlm_lockres_is_dirty(dlm, res));
2368 dlm_lockres_release_ast(dlm, res);
2369
2370 mlog(0, "about to wait on migration_wq, dirty=%s\n",
2371 res->state & DLM_LOCK_RES_DIRTY ? "yes" : "no");
2372 /* if the extra ref we just put was the final one, this
2373 * will pass thru immediately. otherwise, we need to wait
2374 * for the last ast to finish. */
2375again:
2376 ret = wait_event_interruptible_timeout(dlm->migration_wq,
2377 dlm_migration_can_proceed(dlm, res, target),
2378 msecs_to_jiffies(1000));
2379 if (ret < 0) {
2380 mlog(0, "woken again: migrating? %s, dead? %s\n",
2381 res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
2382 test_bit(target, dlm->domain_map) ? "no":"yes");
2383 } else {
2384 mlog(0, "all is well: migrating? %s, dead? %s\n",
2385 res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
2386 test_bit(target, dlm->domain_map) ? "no":"yes");
2387 }
2388 if (!dlm_migration_can_proceed(dlm, res, target)) {
2389 mlog(0, "trying again...\n");
2390 goto again;
2391 }
2392
2393 /* did the target go down or die? */
2394 spin_lock(&dlm->spinlock);
2395 if (!test_bit(target, dlm->domain_map)) {
2396 mlog(ML_ERROR, "aha. migration target %u just went down\n",
2397 target);
2398 ret = -EHOSTDOWN;
2399 }
2400 spin_unlock(&dlm->spinlock);
2401
2402 /*
2403 * at this point:
2404 *
2405 * o the DLM_LOCK_RES_MIGRATING flag is set
2406 * o there are no pending asts on this lockres
2407 * o all processes trying to reserve an ast on this
2408 * lockres must wait for the MIGRATING flag to clear
2409 */
2410 return ret;
2411}
2412
2413/* last step in the migration process.
2414 * original master calls this to free all of the dlm_lock
2415 * structures that used to be for other nodes. */
2416static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
2417 struct dlm_lock_resource *res)
2418{
2419 struct list_head *iter, *iter2;
2420 struct list_head *queue = &res->granted;
2421 int i;
2422 struct dlm_lock *lock;
2423
2424 assert_spin_locked(&res->spinlock);
2425
2426 BUG_ON(res->owner == dlm->node_num);
2427
2428 for (i=0; i<3; i++) {
2429 list_for_each_safe(iter, iter2, queue) {
2430 lock = list_entry (iter, struct dlm_lock, list);
2431 if (lock->ml.node != dlm->node_num) {
2432 mlog(0, "putting lock for node %u\n",
2433 lock->ml.node);
2434 /* be extra careful */
2435 BUG_ON(!list_empty(&lock->ast_list));
2436 BUG_ON(!list_empty(&lock->bast_list));
2437 BUG_ON(lock->ast_pending);
2438 BUG_ON(lock->bast_pending);
2439 list_del_init(&lock->list);
2440 dlm_lock_put(lock);
2441 }
2442 }
2443 queue++;
2444 }
2445}
2446
2447/* for now this is not too intelligent. we will
2448 * need stats to make this do the right thing.
2449 * this just finds the first lock on one of the
2450 * queues and uses that node as the target. */
2451static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
2452 struct dlm_lock_resource *res)
2453{
2454 int i;
2455 struct list_head *queue = &res->granted;
2456 struct list_head *iter;
2457 struct dlm_lock *lock;
2458 int nodenum;
2459
2460 assert_spin_locked(&dlm->spinlock);
2461
2462 spin_lock(&res->spinlock);
2463 for (i=0; i<3; i++) {
2464 list_for_each(iter, queue) {
2465 /* up to the caller to make sure this node
2466 * is alive */
2467 lock = list_entry (iter, struct dlm_lock, list);
2468 if (lock->ml.node != dlm->node_num) {
2469 spin_unlock(&res->spinlock);
2470 return lock->ml.node;
2471 }
2472 }
2473 queue++;
2474 }
2475 spin_unlock(&res->spinlock);
2476 mlog(0, "have not found a suitable target yet! checking domain map\n");
2477
2478 /* ok now we're getting desperate. pick anyone alive. */
2479 nodenum = -1;
2480 while (1) {
2481 nodenum = find_next_bit(dlm->domain_map,
2482 O2NM_MAX_NODES, nodenum+1);
2483 mlog(0, "found %d in domain map\n", nodenum);
2484 if (nodenum >= O2NM_MAX_NODES)
2485 break;
2486 if (nodenum != dlm->node_num) {
2487 mlog(0, "picking %d\n", nodenum);
2488 return nodenum;
2489 }
2490 }
2491
2492 mlog(0, "giving up. no master to migrate to\n");
2493 return DLM_LOCK_RES_OWNER_UNKNOWN;
2494}
2495
2496
2497
2498/* this is called by the new master once all lockres
2499 * data has been received */
2500static int dlm_do_migrate_request(struct dlm_ctxt *dlm,
2501 struct dlm_lock_resource *res,
2502 u8 master, u8 new_master,
2503 struct dlm_node_iter *iter)
2504{
2505 struct dlm_migrate_request migrate;
2506 int ret, status = 0;
2507 int nodenum;
2508
2509 memset(&migrate, 0, sizeof(migrate));
2510 migrate.namelen = res->lockname.len;
2511 memcpy(migrate.name, res->lockname.name, migrate.namelen);
2512 migrate.new_master = new_master;
2513 migrate.master = master;
2514
2515 ret = 0;
2516
2517 /* send message to all nodes, except the master and myself */
2518 while ((nodenum = dlm_node_iter_next(iter)) >= 0) {
2519 if (nodenum == master ||
2520 nodenum == new_master)
2521 continue;
2522
2523 ret = o2net_send_message(DLM_MIGRATE_REQUEST_MSG, dlm->key,
2524 &migrate, sizeof(migrate), nodenum,
2525 &status);
2526 if (ret < 0)
2527 mlog_errno(ret);
2528 else if (status < 0) {
2529 mlog(0, "migrate request (node %u) returned %d!\n",
2530 nodenum, status);
2531 ret = status;
2532 }
2533 }
2534
2535 if (ret < 0)
2536 mlog_errno(ret);
2537
2538 mlog(0, "returning ret=%d\n", ret);
2539 return ret;
2540}
2541
2542
2543/* if there is an existing mle for this lockres, we now know who the master is.
2544 * (the one who sent us *this* message) we can clear it up right away.
2545 * since the process that put the mle on the list still has a reference to it,
2546 * we can unhash it now, set the master and wake the process. as a result,
2547 * we will have no mle in the list to start with. now we can add an mle for
2548 * the migration and this should be the only one found for those scanning the
2549 * list. */
2550int dlm_migrate_request_handler(struct o2net_msg *msg, u32 len, void *data)
2551{
2552 struct dlm_ctxt *dlm = data;
2553 struct dlm_lock_resource *res = NULL;
2554 struct dlm_migrate_request *migrate = (struct dlm_migrate_request *) msg->buf;
2555 struct dlm_master_list_entry *mle = NULL, *oldmle = NULL;
2556 const char *name;
a3d33291 2557 unsigned int namelen, hash;
6714d8e8
KH		 2558 int ret = 0;
2559
2560 if (!dlm_grab(dlm))
2561 return -EINVAL;
2562
2563 name = migrate->name;
2564 namelen = migrate->namelen;
a3d33291 2565 hash = dlm_lockid_hash(name, namelen);
6714d8e8
KH		 2566
2567 /* preallocate.. if this fails, abort */
2568 mle = (struct dlm_master_list_entry *) kmem_cache_alloc(dlm_mle_cache,
2569 GFP_KERNEL);
2570
2571 if (!mle) {
2572 ret = -ENOMEM;
2573 goto leave;
2574 }
2575
2576 /* check for pre-existing lock */
2577 spin_lock(&dlm->spinlock);
a3d33291 2578 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
6714d8e8
KH		 2579 spin_lock(&dlm->master_lock);
2580
2581 if (res) {
2582 spin_lock(&res->spinlock);
2583 if (res->state & DLM_LOCK_RES_RECOVERING) {
2584 /* if all is working ok, this can only mean that we got
2585 * a migrate request from a node that we now see as
2586 * dead. what can we do here? drop it to the floor? */
2587 spin_unlock(&res->spinlock);
2588 mlog(ML_ERROR, "Got a migrate request, but the "
2589 "lockres is marked as recovering!");
2590 kmem_cache_free(dlm_mle_cache, mle);
2591 ret = -EINVAL; /* need a better solution */
2592 goto unlock;
2593 }
2594 res->state |= DLM_LOCK_RES_MIGRATING;
2595 spin_unlock(&res->spinlock);
2596 }
2597
2598 /* ignore status. only nonzero status would BUG. */
2599 ret = dlm_add_migration_mle(dlm, res, mle, &oldmle,
2600 name, namelen,
2601 migrate->new_master,
2602 migrate->master);
2603
2604unlock:
2605 spin_unlock(&dlm->master_lock);
2606 spin_unlock(&dlm->spinlock);
2607
2608 if (oldmle) {
2609 /* master is known, detach if not already detached */
2610 dlm_mle_detach_hb_events(dlm, oldmle);
2611 dlm_put_mle(oldmle);
2612 }
2613
2614 if (res)
2615 dlm_lockres_put(res);
2616leave:
2617 dlm_put(dlm);
2618 return ret;
2619}
2620
2621/* must be holding dlm->spinlock and dlm->master_lock
2622 * when adding a migration mle, we can clear any other mles
2623 * in the master list because we know with certainty that
2624 * the master is "master". so we remove any old mle from
2625 * the list after setting it's master field, and then add
2626 * the new migration mle. this way we can hold with the rule
2627 * of having only one mle for a given lock name at all times. */
2628static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
2629 struct dlm_lock_resource *res,
2630 struct dlm_master_list_entry *mle,
2631 struct dlm_master_list_entry **oldmle,
2632 const char *name, unsigned int namelen,
2633 u8 new_master, u8 master)
2634{
2635 int found;
2636 int ret = 0;
2637
2638 *oldmle = NULL;
2639
2640 mlog_entry_void();
2641
2642 assert_spin_locked(&dlm->spinlock);
2643 assert_spin_locked(&dlm->master_lock);
2644
2645 /* caller is responsible for any ref taken here on oldmle */
2646 found = dlm_find_mle(dlm, oldmle, (char *)name, namelen);
2647 if (found) {
2648 struct dlm_master_list_entry *tmp = *oldmle;
2649 spin_lock(&tmp->spinlock);
2650 if (tmp->type == DLM_MLE_MIGRATION) {
2651 if (master == dlm->node_num) {
2652 /* ah another process raced me to it */
2653 mlog(0, "tried to migrate %.*s, but some "
2654 "process beat me to it\n",
2655 namelen, name);
2656 ret = -EEXIST;
2657 } else {
2658 /* bad. 2 NODES are trying to migrate! */
2659 mlog(ML_ERROR, "migration error mle: "
2660 "master=%u new_master=%u // request: "
2661 "master=%u new_master=%u // "
2662 "lockres=%.*s\n",
2663 tmp->master, tmp->new_master,
2664 master, new_master,
2665 namelen, name);
2666 BUG();
2667 }
2668 } else {
2669 /* this is essentially what assert_master does */
2670 tmp->master = master;
2671 atomic_set(&tmp->woken, 1);
2672 wake_up(&tmp->wq);
2673 /* remove it from the list so that only one
2674 * mle will be found */
2675 list_del_init(&tmp->list);
da01ad05 2676 __dlm_mle_detach_hb_events(dlm, mle);
6714d8e8
KH		 2677 }
2678 spin_unlock(&tmp->spinlock);
2679 }
2680
2681 /* now add a migration mle to the tail of the list */
2682 dlm_init_mle(mle, DLM_MLE_MIGRATION, dlm, res, name, namelen);
2683 mle->new_master = new_master;
2684 mle->master = master;
2685 /* do this for consistency with other mle types */
2686 set_bit(new_master, mle->maybe_map);
2687 list_add(&mle->list, &dlm->master_list);
2688
2689 return ret;
2690}
2691
2692
2693void dlm_clean_master_list(struct dlm_ctxt *dlm, u8 dead_node)
2694{
2695 struct list_head *iter, *iter2;
2696 struct dlm_master_list_entry *mle;
2697 struct dlm_lock_resource *res;
a3d33291 2698 unsigned int hash;
6714d8e8
KH		 2699
2700 mlog_entry("dlm=%s, dead node=%u\n", dlm->name, dead_node);
2701top:
2702 assert_spin_locked(&dlm->spinlock);
2703
2704 /* clean the master list */
2705 spin_lock(&dlm->master_lock);
2706 list_for_each_safe(iter, iter2, &dlm->master_list) {
2707 mle = list_entry(iter, struct dlm_master_list_entry, list);
2708
2709 BUG_ON(mle->type != DLM_MLE_BLOCK &&
2710 mle->type != DLM_MLE_MASTER &&
2711 mle->type != DLM_MLE_MIGRATION);
2712
2713 /* MASTER mles are initiated locally. the waiting
2714 * process will notice the node map change
2715 * shortly. let that happen as normal. */
2716 if (mle->type == DLM_MLE_MASTER)
2717 continue;
2718
2719
2720 /* BLOCK mles are initiated by other nodes.
2721 * need to clean up if the dead node would have
2722 * been the master. */
2723 if (mle->type == DLM_MLE_BLOCK) {
2724 int bit;
2725
2726 spin_lock(&mle->spinlock);
2727 bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
2728 if (bit != dead_node) {
2729 mlog(0, "mle found, but dead node %u would "
2730 "not have been master\n", dead_node);
2731 spin_unlock(&mle->spinlock);
2732 } else {
2733 /* must drop the refcount by one since the
2734 * assert_master will never arrive. this
2735 * may result in the mle being unlinked and
2736 * freed, but there may still be a process
2737 * waiting in the dlmlock path which is fine. */
2738 mlog(ML_ERROR, "node %u was expected master\n",
2739 dead_node);
2740 atomic_set(&mle->woken, 1);
2741 spin_unlock(&mle->spinlock);
2742 wake_up(&mle->wq);
f671c09b
KH		 2743 /* do not need events any longer, so detach
2744 * from heartbeat */
2745 __dlm_mle_detach_hb_events(dlm, mle);
6714d8e8
KH		 2746 __dlm_put_mle(mle);
2747 }
2748 continue;
2749 }
2750
2751 /* everything else is a MIGRATION mle */
2752
2753 /* the rule for MIGRATION mles is that the master
2754 * becomes UNKNOWN if *either* the original or
2755 * the new master dies. all UNKNOWN lockreses
2756 * are sent to whichever node becomes the recovery
2757 * master. the new master is responsible for
2758 * determining if there is still a master for
2759 * this lockres, or if he needs to take over
2760 * mastery. either way, this node should expect
2761 * another message to resolve this. */
2762 if (mle->master != dead_node &&
2763 mle->new_master != dead_node)
2764 continue;
2765
2766 /* if we have reached this point, this mle needs to
2767 * be removed from the list and freed. */
2768
2769 /* remove from the list early. NOTE: unlinking
2770 * list_head while in list_for_each_safe */
da01ad05 2771 __dlm_mle_detach_hb_events(dlm, mle);
6714d8e8
KH		 2772 spin_lock(&mle->spinlock);
2773 list_del_init(&mle->list);
2774 atomic_set(&mle->woken, 1);
2775 spin_unlock(&mle->spinlock);
2776 wake_up(&mle->wq);
2777
2778 mlog(0, "node %u died during migration from "
2779 "%u to %u!\n", dead_node,
2780 mle->master, mle->new_master);
2781 /* if there is a lockres associated with this
2782 * mle, find it and set its owner to UNKNOWN */
a3d33291 2783 hash = dlm_lockid_hash(mle->u.name.name, mle->u.name.len);
6714d8e8 2784 res = __dlm_lookup_lockres(dlm, mle->u.name.name,
a3d33291 2785 mle->u.name.len, hash);
6714d8e8
KH		 2786 if (res) {
2787 /* unfortunately if we hit this rare case, our
2788 * lock ordering is messed. we need to drop
2789 * the master lock so that we can take the
2790 * lockres lock, meaning that we will have to
2791 * restart from the head of list. */
2792 spin_unlock(&dlm->master_lock);
2793
2794 /* move lockres onto recovery list */
2795 spin_lock(&res->spinlock);
2796 dlm_set_lockres_owner(dlm, res,
2797 DLM_LOCK_RES_OWNER_UNKNOWN);
2798 dlm_move_lockres_to_recovery_list(dlm, res);
2799 spin_unlock(&res->spinlock);
2800 dlm_lockres_put(res);
2801
f671c09b
KH		 2802 /* about to get rid of mle, detach from heartbeat */
2803 __dlm_mle_detach_hb_events(dlm, mle);
2804
6714d8e8
KH		 2805 /* dump the mle */
2806 spin_lock(&dlm->master_lock);
2807 __dlm_put_mle(mle);
2808 spin_unlock(&dlm->master_lock);
2809
2810 /* restart */
2811 goto top;
2812 }
2813
2814 /* this may be the last reference */
2815 __dlm_put_mle(mle);
2816 }
2817 spin_unlock(&dlm->master_lock);
2818}
2819
2820
2821int dlm_finish_migration(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
2822 u8 old_master)
2823{
2824 struct dlm_node_iter iter;
2825 int ret = 0;
2826
2827 spin_lock(&dlm->spinlock);
2828 dlm_node_iter_init(dlm->domain_map, &iter);
2829 clear_bit(old_master, iter.node_map);
2830 clear_bit(dlm->node_num, iter.node_map);
2831 spin_unlock(&dlm->spinlock);
2832
2833 mlog(0, "now time to do a migrate request to other nodes\n");
2834 ret = dlm_do_migrate_request(dlm, res, old_master,
2835 dlm->node_num, &iter);
2836 if (ret < 0) {
2837 mlog_errno(ret);
2838 goto leave;
2839 }
2840
2841 mlog(0, "doing assert master of %.*s to all except the original node\n",
2842 res->lockname.len, res->lockname.name);
2843 /* this call now finishes out the nodemap
2844 * even if one or more nodes die */
2845 ret = dlm_do_assert_master(dlm, res->lockname.name,
2846 res->lockname.len, iter.node_map,
2847 DLM_ASSERT_MASTER_FINISH_MIGRATION);
2848 if (ret < 0) {
2849 /* no longer need to retry. all living nodes contacted. */
2850 mlog_errno(ret);
2851 ret = 0;
2852 }
2853
2854 memset(iter.node_map, 0, sizeof(iter.node_map));
2855 set_bit(old_master, iter.node_map);
2856 mlog(0, "doing assert master of %.*s back to %u\n",
2857 res->lockname.len, res->lockname.name, old_master);
2858 ret = dlm_do_assert_master(dlm, res->lockname.name,
2859 res->lockname.len, iter.node_map,
2860 DLM_ASSERT_MASTER_FINISH_MIGRATION);
2861 if (ret < 0) {
2862 mlog(0, "assert master to original master failed "
2863 "with %d.\n", ret);
2864 /* the only nonzero status here would be because of
2865 * a dead original node. we're done. */
2866 ret = 0;
2867 }
2868
2869 /* all done, set the owner, clear the flag */
2870 spin_lock(&res->spinlock);
2871 dlm_set_lockres_owner(dlm, res, dlm->node_num);
2872 res->state &= ~DLM_LOCK_RES_MIGRATING;
2873 spin_unlock(&res->spinlock);
2874 /* re-dirty it on the new master */
2875 dlm_kick_thread(dlm, res);
2876 wake_up(&res->wq);
2877leave:
2878 return ret;
2879}
2880
2881/*
2882 * LOCKRES AST REFCOUNT
2883 * this is integral to migration
2884 */
2885
2886/* for future intent to call an ast, reserve one ahead of time.
2887 * this should be called only after waiting on the lockres
2888 * with dlm_wait_on_lockres, and while still holding the
2889 * spinlock after the call. */
2890void __dlm_lockres_reserve_ast(struct dlm_lock_resource *res)
2891{
2892 assert_spin_locked(&res->spinlock);
2893 if (res->state & DLM_LOCK_RES_MIGRATING) {
2894 __dlm_print_one_lock_resource(res);
2895 }
2896 BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
2897
2898 atomic_inc(&res->asts_reserved);
2899}
2900
2901/*
2902 * used to drop the reserved ast, either because it went unused,
2903 * or because the ast/bast was actually called.
2904 *
2905 * also, if there is a pending migration on this lockres,
2906 * and this was the last pending ast on the lockres,
2907 * atomically set the MIGRATING flag before we drop the lock.
2908 * this is how we ensure that migration can proceed with no
2909 * asts in progress. note that it is ok if the state of the
2910 * queues is such that a lock should be granted in the future
2911 * or that a bast should be fired, because the new master will
2912 * shuffle the lists on this lockres as soon as it is migrated.
2913 */
2914void dlm_lockres_release_ast(struct dlm_ctxt *dlm,
2915 struct dlm_lock_resource *res)
2916{
2917 if (!atomic_dec_and_lock(&res->asts_reserved, &res->spinlock))
2918 return;
2919
2920 if (!res->migration_pending) {
2921 spin_unlock(&res->spinlock);
2922 return;
2923 }
2924
2925 BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
2926 res->migration_pending = 0;
2927 res->state |= DLM_LOCK_RES_MIGRATING;
2928 spin_unlock(&res->spinlock);
2929 wake_up(&res->wq);
2930 wake_up(&dlm->migration_wq);
2931}
Linux 6.x block layer and io_uring tree(s)