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ocfs2: purge lockres' sooner
[linux-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);
aa852354
KH		 374 if (!atomic_read(&mle->mle_refs.refcount)) {
375 /* this may or may not crash, but who cares.
376 * it's a BUG. */
377 mlog(ML_ERROR, "bad mle: %p\n", mle);
378 dlm_print_one_mle(mle);
379 BUG();
380 } else
381 kref_put(&mle->mle_refs, dlm_mle_release);
6714d8e8
KH		 382}
383
384
385/* must not have any spinlocks coming in */
386static void dlm_put_mle(struct dlm_master_list_entry *mle)
387{
388 struct dlm_ctxt *dlm;
389 dlm = mle->dlm;
390
391 spin_lock(&dlm->spinlock);
392 spin_lock(&dlm->master_lock);
393 __dlm_put_mle(mle);
394 spin_unlock(&dlm->master_lock);
395 spin_unlock(&dlm->spinlock);
396}
397
398static inline void dlm_get_mle(struct dlm_master_list_entry *mle)
399{
400 kref_get(&mle->mle_refs);
401}
402
403static void dlm_init_mle(struct dlm_master_list_entry *mle,
404 enum dlm_mle_type type,
405 struct dlm_ctxt *dlm,
406 struct dlm_lock_resource *res,
407 const char *name,
408 unsigned int namelen)
409{
410 assert_spin_locked(&dlm->spinlock);
411
412 mle->dlm = dlm;
413 mle->type = type;
414 INIT_LIST_HEAD(&mle->list);
415 INIT_LIST_HEAD(&mle->hb_events);
416 memset(mle->maybe_map, 0, sizeof(mle->maybe_map));
417 spin_lock_init(&mle->spinlock);
418 init_waitqueue_head(&mle->wq);
419 atomic_set(&mle->woken, 0);
420 kref_init(&mle->mle_refs);
421 memset(mle->response_map, 0, sizeof(mle->response_map));
422 mle->master = O2NM_MAX_NODES;
423 mle->new_master = O2NM_MAX_NODES;
a2bf0477 424 mle->inuse = 0;
6714d8e8
KH		 425
426 if (mle->type == DLM_MLE_MASTER) {
427 BUG_ON(!res);
428 mle->u.res = res;
429 } else if (mle->type == DLM_MLE_BLOCK) {
430 BUG_ON(!name);
431 memcpy(mle->u.name.name, name, namelen);
432 mle->u.name.len = namelen;
433 } else /* DLM_MLE_MIGRATION */ {
434 BUG_ON(!name);
435 memcpy(mle->u.name.name, name, namelen);
436 mle->u.name.len = namelen;
437 }
438
439 /* copy off the node_map and register hb callbacks on our copy */
440 memcpy(mle->node_map, dlm->domain_map, sizeof(mle->node_map));
441 memcpy(mle->vote_map, dlm->domain_map, sizeof(mle->vote_map));
442 clear_bit(dlm->node_num, mle->vote_map);
443 clear_bit(dlm->node_num, mle->node_map);
444
445 /* attach the mle to the domain node up/down events */
446 __dlm_mle_attach_hb_events(dlm, mle);
447}
448
449
450/* returns 1 if found, 0 if not */
451static int dlm_find_mle(struct dlm_ctxt *dlm,
452 struct dlm_master_list_entry **mle,
453 char *name, unsigned int namelen)
454{
455 struct dlm_master_list_entry *tmpmle;
456 struct list_head *iter;
457
458 assert_spin_locked(&dlm->master_lock);
459
460 list_for_each(iter, &dlm->master_list) {
461 tmpmle = list_entry(iter, struct dlm_master_list_entry, list);
462 if (!dlm_mle_equal(dlm, tmpmle, name, namelen))
463 continue;
464 dlm_get_mle(tmpmle);
465 *mle = tmpmle;
466 return 1;
467 }
468 return 0;
469}
470
471void dlm_hb_event_notify_attached(struct dlm_ctxt *dlm, int idx, int node_up)
472{
473 struct dlm_master_list_entry *mle;
474 struct list_head *iter;
475
476 assert_spin_locked(&dlm->spinlock);
477
478 list_for_each(iter, &dlm->mle_hb_events) {
479 mle = list_entry(iter, struct dlm_master_list_entry,
480 hb_events);
481 if (node_up)
482 dlm_mle_node_up(dlm, mle, NULL, idx);
483 else
484 dlm_mle_node_down(dlm, mle, NULL, idx);
485 }
486}
487
488static void dlm_mle_node_down(struct dlm_ctxt *dlm,
489 struct dlm_master_list_entry *mle,
490 struct o2nm_node *node, int idx)
491{
492 spin_lock(&mle->spinlock);
493
494 if (!test_bit(idx, mle->node_map))
495 mlog(0, "node %u already removed from nodemap!\n", idx);
496 else
497 clear_bit(idx, mle->node_map);
498
499 spin_unlock(&mle->spinlock);
500}
501
502static void dlm_mle_node_up(struct dlm_ctxt *dlm,
503 struct dlm_master_list_entry *mle,
504 struct o2nm_node *node, int idx)
505{
506 spin_lock(&mle->spinlock);
507
508 if (test_bit(idx, mle->node_map))
509 mlog(0, "node %u already in node map!\n", idx);
510 else
511 set_bit(idx, mle->node_map);
512
513 spin_unlock(&mle->spinlock);
514}
515
516
517int dlm_init_mle_cache(void)
518{
519 dlm_mle_cache = kmem_cache_create("dlm_mle_cache",
520 sizeof(struct dlm_master_list_entry),
521 0, SLAB_HWCACHE_ALIGN,
522 NULL, NULL);
523 if (dlm_mle_cache == NULL)
524 return -ENOMEM;
525 return 0;
526}
527
528void dlm_destroy_mle_cache(void)
529{
530 if (dlm_mle_cache)
531 kmem_cache_destroy(dlm_mle_cache);
532}
533
534static void dlm_mle_release(struct kref *kref)
535{
536 struct dlm_master_list_entry *mle;
537 struct dlm_ctxt *dlm;
538
539 mlog_entry_void();
540
541 mle = container_of(kref, struct dlm_master_list_entry, mle_refs);
542 dlm = mle->dlm;
543
544 if (mle->type != DLM_MLE_MASTER) {
545 mlog(0, "calling mle_release for %.*s, type %d\n",
546 mle->u.name.len, mle->u.name.name, mle->type);
547 } else {
548 mlog(0, "calling mle_release for %.*s, type %d\n",
549 mle->u.res->lockname.len,
550 mle->u.res->lockname.name, mle->type);
551 }
552 assert_spin_locked(&dlm->spinlock);
553 assert_spin_locked(&dlm->master_lock);
554
555 /* remove from list if not already */
556 if (!list_empty(&mle->list))
557 list_del_init(&mle->list);
558
559 /* detach the mle from the domain node up/down events */
560 __dlm_mle_detach_hb_events(dlm, mle);
561
562 /* NOTE: kfree under spinlock here.
563 * if this is bad, we can move this to a freelist. */
564 kmem_cache_free(dlm_mle_cache, mle);
565}
566
567
568/*
569 * LOCK RESOURCE FUNCTIONS
570 */
571
572static void dlm_set_lockres_owner(struct dlm_ctxt *dlm,
573 struct dlm_lock_resource *res,
574 u8 owner)
575{
576 assert_spin_locked(&res->spinlock);
577
578 mlog_entry("%.*s, %u\n", res->lockname.len, res->lockname.name, owner);
579
580 if (owner == dlm->node_num)
581 atomic_inc(&dlm->local_resources);
582 else if (owner == DLM_LOCK_RES_OWNER_UNKNOWN)
583 atomic_inc(&dlm->unknown_resources);
584 else
585 atomic_inc(&dlm->remote_resources);
586
587 res->owner = owner;
588}
589
590void dlm_change_lockres_owner(struct dlm_ctxt *dlm,
591 struct dlm_lock_resource *res, u8 owner)
592{
593 assert_spin_locked(&res->spinlock);
594
595 if (owner == res->owner)
596 return;
597
598 if (res->owner == dlm->node_num)
599 atomic_dec(&dlm->local_resources);
600 else if (res->owner == DLM_LOCK_RES_OWNER_UNKNOWN)
601 atomic_dec(&dlm->unknown_resources);
602 else
603 atomic_dec(&dlm->remote_resources);
604
605 dlm_set_lockres_owner(dlm, res, owner);
606}
607
608
609static void dlm_lockres_release(struct kref *kref)
610{
611 struct dlm_lock_resource *res;
612
613 res = container_of(kref, struct dlm_lock_resource, refs);
614
615 /* This should not happen -- all lockres' have a name
616 * associated with them at init time. */
617 BUG_ON(!res->lockname.name);
618
619 mlog(0, "destroying lockres %.*s\n", res->lockname.len,
620 res->lockname.name);
621
a7f90d83
KH		 622 if (!hlist_unhashed(&res->hash_node) ||
623 !list_empty(&res->granted) ||
624 !list_empty(&res->converting) ||
625 !list_empty(&res->blocked) ||
626 !list_empty(&res->dirty) ||
627 !list_empty(&res->recovering) ||
628 !list_empty(&res->purge)) {
629 mlog(ML_ERROR,
630 "Going to BUG for resource %.*s."
631 " We're on a list! [%c%c%c%c%c%c%c]\n",
632 res->lockname.len, res->lockname.name,
633 !hlist_unhashed(&res->hash_node) ? 'H' : ' ',
634 !list_empty(&res->granted) ? 'G' : ' ',
635 !list_empty(&res->converting) ? 'C' : ' ',
636 !list_empty(&res->blocked) ? 'B' : ' ',
637 !list_empty(&res->dirty) ? 'D' : ' ',
638 !list_empty(&res->recovering) ? 'R' : ' ',
639 !list_empty(&res->purge) ? 'P' : ' ');
640
641 dlm_print_one_lock_resource(res);
642 }
643
6714d8e8
KH		 644 /* By the time we're ready to blow this guy away, we shouldn't
645 * be on any lists. */
81f2094a 646 BUG_ON(!hlist_unhashed(&res->hash_node));
6714d8e8
KH		 647 BUG_ON(!list_empty(&res->granted));
648 BUG_ON(!list_empty(&res->converting));
649 BUG_ON(!list_empty(&res->blocked));
650 BUG_ON(!list_empty(&res->dirty));
651 BUG_ON(!list_empty(&res->recovering));
652 BUG_ON(!list_empty(&res->purge));
653
654 kfree(res->lockname.name);
655
656 kfree(res);
657}
658
6714d8e8
KH		 659void dlm_lockres_put(struct dlm_lock_resource *res)
660{
661 kref_put(&res->refs, dlm_lockres_release);
662}
663
664static void dlm_init_lockres(struct dlm_ctxt *dlm,
665 struct dlm_lock_resource *res,
666 const char *name, unsigned int namelen)
667{
668 char *qname;
669
670 /* If we memset here, we lose our reference to the kmalloc'd
671 * res->lockname.name, so be sure to init every field
672 * correctly! */
673
674 qname = (char *) res->lockname.name;
675 memcpy(qname, name, namelen);
676
677 res->lockname.len = namelen;
a3d33291 678 res->lockname.hash = dlm_lockid_hash(name, namelen);
6714d8e8
KH		 679
680 init_waitqueue_head(&res->wq);
681 spin_lock_init(&res->spinlock);
81f2094a 682 INIT_HLIST_NODE(&res->hash_node);
6714d8e8
KH		 683 INIT_LIST_HEAD(&res->granted);
684 INIT_LIST_HEAD(&res->converting);
685 INIT_LIST_HEAD(&res->blocked);
686 INIT_LIST_HEAD(&res->dirty);
687 INIT_LIST_HEAD(&res->recovering);
688 INIT_LIST_HEAD(&res->purge);
689 atomic_set(&res->asts_reserved, 0);
690 res->migration_pending = 0;
691
692 kref_init(&res->refs);
693
694 /* just for consistency */
695 spin_lock(&res->spinlock);
696 dlm_set_lockres_owner(dlm, res, DLM_LOCK_RES_OWNER_UNKNOWN);
697 spin_unlock(&res->spinlock);
698
699 res->state = DLM_LOCK_RES_IN_PROGRESS;
700
701 res->last_used = 0;
702
703 memset(res->lvb, 0, DLM_LVB_LEN);
704}
705
706struct dlm_lock_resource *dlm_new_lockres(struct dlm_ctxt *dlm,
707 const char *name,
708 unsigned int namelen)
709{
710 struct dlm_lock_resource *res;
711
712 res = kmalloc(sizeof(struct dlm_lock_resource), GFP_KERNEL);
713 if (!res)
714 return NULL;
715
716 res->lockname.name = kmalloc(namelen, GFP_KERNEL);
717 if (!res->lockname.name) {
718 kfree(res);
719 return NULL;
720 }
721
722 dlm_init_lockres(dlm, res, name, namelen);
723 return res;
724}
725
726/*
727 * lookup a lock resource by name.
728 * may already exist in the hashtable.
729 * lockid is null terminated
730 *
731 * if not, allocate enough for the lockres and for
732 * the temporary structure used in doing the mastering.
733 *
734 * also, do a lookup in the dlm->master_list to see
735 * if another node has begun mastering the same lock.
736 * if so, there should be a block entry in there
737 * for this name, and we should *not* attempt to master
738 * the lock here. need to wait around for that node
739 * to assert_master (or die).
740 *
741 */
742struct dlm_lock_resource * dlm_get_lock_resource(struct dlm_ctxt *dlm,
743 const char *lockid,
744 int flags)
745{
746 struct dlm_lock_resource *tmpres=NULL, *res=NULL;
747 struct dlm_master_list_entry *mle = NULL;
748 struct dlm_master_list_entry *alloc_mle = NULL;
749 int blocked = 0;
750 int ret, nodenum;
751 struct dlm_node_iter iter;
a3d33291 752 unsigned int namelen, hash;
6714d8e8 753 int tries = 0;
c03872f5 754 int bit, wait_on_recovery = 0;
6714d8e8
KH		 755
756 BUG_ON(!lockid);
757
758 namelen = strlen(lockid);
a3d33291 759 hash = dlm_lockid_hash(lockid, namelen);
6714d8e8
KH		 760
761 mlog(0, "get lockres %s (len %d)\n", lockid, namelen);
762
763lookup:
764 spin_lock(&dlm->spinlock);
a3d33291 765 tmpres = __dlm_lookup_lockres(dlm, lockid, namelen, hash);
6714d8e8
KH		 766 if (tmpres) {
767 spin_unlock(&dlm->spinlock);
768 mlog(0, "found in hash!\n");
769 if (res)
770 dlm_lockres_put(res);
771 res = tmpres;
772 goto leave;
773 }
774
775 if (!res) {
776 spin_unlock(&dlm->spinlock);
777 mlog(0, "allocating a new resource\n");
778 /* nothing found and we need to allocate one. */
779 alloc_mle = (struct dlm_master_list_entry *)
780 kmem_cache_alloc(dlm_mle_cache, GFP_KERNEL);
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 spin_unlock(&res->spinlock);
798 spin_unlock(&dlm->spinlock);
799 /* lockres still marked IN_PROGRESS */
800 goto wake_waiters;
801 }
802
803 /* check master list to see if another node has started mastering it */
804 spin_lock(&dlm->master_lock);
805
806 /* if we found a block, wait for lock to be mastered by another node */
807 blocked = dlm_find_mle(dlm, &mle, (char *)lockid, namelen);
808 if (blocked) {
809 if (mle->type == DLM_MLE_MASTER) {
810 mlog(ML_ERROR, "master entry for nonexistent lock!\n");
811 BUG();
812 } else if (mle->type == DLM_MLE_MIGRATION) {
813 /* migration is in progress! */
814 /* the good news is that we now know the
815 * "current" master (mle->master). */
816
817 spin_unlock(&dlm->master_lock);
818 assert_spin_locked(&dlm->spinlock);
819
820 /* set the lockres owner and hash it */
821 spin_lock(&res->spinlock);
822 dlm_set_lockres_owner(dlm, res, mle->master);
823 __dlm_insert_lockres(dlm, res);
824 spin_unlock(&res->spinlock);
825 spin_unlock(&dlm->spinlock);
826
827 /* master is known, detach */
828 dlm_mle_detach_hb_events(dlm, mle);
829 dlm_put_mle(mle);
830 mle = NULL;
831 goto wake_waiters;
832 }
833 } else {
834 /* go ahead and try to master lock on this node */
835 mle = alloc_mle;
836 /* make sure this does not get freed below */
837 alloc_mle = NULL;
838 dlm_init_mle(mle, DLM_MLE_MASTER, dlm, res, NULL, 0);
839 set_bit(dlm->node_num, mle->maybe_map);
840 list_add(&mle->list, &dlm->master_list);
c03872f5
KH		 841
842 /* still holding the dlm spinlock, check the recovery map
843 * to see if there are any nodes that still need to be
844 * considered. these will not appear in the mle nodemap
845 * but they might own this lockres. wait on them. */
846 bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
847 if (bit < O2NM_MAX_NODES) {
848 mlog(ML_NOTICE, "%s:%.*s: at least one node (%d) to"
849 "recover before lock mastery can begin\n",
850 dlm->name, namelen, (char *)lockid, bit);
851 wait_on_recovery = 1;
852 }
6714d8e8
KH		 853 }
854
855 /* at this point there is either a DLM_MLE_BLOCK or a
856 * DLM_MLE_MASTER on the master list, so it's safe to add the
857 * lockres to the hashtable. anyone who finds the lock will
858 * still have to wait on the IN_PROGRESS. */
859
860 /* finally add the lockres to its hash bucket */
861 __dlm_insert_lockres(dlm, res);
862 /* get an extra ref on the mle in case this is a BLOCK
863 * if so, the creator of the BLOCK may try to put the last
864 * ref at this time in the assert master handler, so we
865 * need an extra one to keep from a bad ptr deref. */
a2bf0477 866 dlm_get_mle_inuse(mle);
6714d8e8
KH		 867 spin_unlock(&dlm->master_lock);
868 spin_unlock(&dlm->spinlock);
869
c03872f5
KH		 870 while (wait_on_recovery) {
871 /* any cluster changes that occurred after dropping the
872 * dlm spinlock would be detectable be a change on the mle,
873 * so we only need to clear out the recovery map once. */
874 if (dlm_is_recovery_lock(lockid, namelen)) {
875 mlog(ML_NOTICE, "%s: recovery map is not empty, but "
876 "must master $RECOVERY lock now\n", dlm->name);
877 if (!dlm_pre_master_reco_lockres(dlm, res))
878 wait_on_recovery = 0;
879 else {
880 mlog(0, "%s: waiting 500ms for heartbeat state "
881 "change\n", dlm->name);
882 msleep(500);
883 }
884 continue;
885 }
886
887 dlm_kick_recovery_thread(dlm);
888 msleep(100);
889 dlm_wait_for_recovery(dlm);
890
891 spin_lock(&dlm->spinlock);
892 bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
893 if (bit < O2NM_MAX_NODES) {
894 mlog(ML_NOTICE, "%s:%.*s: at least one node (%d) to"
895 "recover before lock mastery can begin\n",
896 dlm->name, namelen, (char *)lockid, bit);
897 wait_on_recovery = 1;
898 } else
899 wait_on_recovery = 0;
900 spin_unlock(&dlm->spinlock);
901 }
902
6714d8e8
KH		 903 /* must wait for lock to be mastered elsewhere */
904 if (blocked)
905 goto wait;
906
907redo_request:
908 ret = -EINVAL;
909 dlm_node_iter_init(mle->vote_map, &iter);
910 while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
911 ret = dlm_do_master_request(mle, nodenum);
912 if (ret < 0)
913 mlog_errno(ret);
914 if (mle->master != O2NM_MAX_NODES) {
915 /* found a master ! */
9c6510a5
KH		 916 if (mle->master <= nodenum)
917 break;
918 /* if our master request has not reached the master
919 * yet, keep going until it does. this is how the
920 * master will know that asserts are needed back to
921 * the lower nodes. */
922 mlog(0, "%s:%.*s: requests only up to %u but master "
923 "is %u, keep going\n", dlm->name, namelen,
924 lockid, nodenum, mle->master);
6714d8e8
KH		 925 }
926 }
927
928wait:
929 /* keep going until the response map includes all nodes */
930 ret = dlm_wait_for_lock_mastery(dlm, res, mle, &blocked);
931 if (ret < 0) {
932 mlog(0, "%s:%.*s: node map changed, redo the "
933 "master request now, blocked=%d\n",
934 dlm->name, res->lockname.len,
935 res->lockname.name, blocked);
936 if (++tries > 20) {
937 mlog(ML_ERROR, "%s:%.*s: spinning on "
938 "dlm_wait_for_lock_mastery, blocked=%d\n",
939 dlm->name, res->lockname.len,
940 res->lockname.name, blocked);
941 dlm_print_one_lock_resource(res);
942 /* dlm_print_one_mle(mle); */
943 tries = 0;
944 }
945 goto redo_request;
946 }
947
948 mlog(0, "lockres mastered by %u\n", res->owner);
949 /* make sure we never continue without this */
950 BUG_ON(res->owner == O2NM_MAX_NODES);
951
952 /* master is known, detach if not already detached */
953 dlm_mle_detach_hb_events(dlm, mle);
954 dlm_put_mle(mle);
955 /* put the extra ref */
a2bf0477 956 dlm_put_mle_inuse(mle);
6714d8e8
KH		 957
958wake_waiters:
959 spin_lock(&res->spinlock);
960 res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
961 spin_unlock(&res->spinlock);
962 wake_up(&res->wq);
963
964leave:
965 /* need to free the unused mle */
966 if (alloc_mle)
967 kmem_cache_free(dlm_mle_cache, alloc_mle);
968
969 return res;
970}
971
972
973#define DLM_MASTERY_TIMEOUT_MS 5000
974
975static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
976 struct dlm_lock_resource *res,
977 struct dlm_master_list_entry *mle,
978 int *blocked)
979{
980 u8 m;
981 int ret, bit;
982 int map_changed, voting_done;
983 int assert, sleep;
984
985recheck:
986 ret = 0;
987 assert = 0;
988
989 /* check if another node has already become the owner */
990 spin_lock(&res->spinlock);
991 if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
9c6510a5
KH		 992 mlog(0, "%s:%.*s: owner is suddenly %u\n", dlm->name,
993 res->lockname.len, res->lockname.name, res->owner);
6714d8e8 994 spin_unlock(&res->spinlock);
9c6510a5
KH		 995 /* this will cause the master to re-assert across
996 * the whole cluster, freeing up mles */
997 ret = dlm_do_master_request(mle, res->owner);
998 if (ret < 0) {
999 /* give recovery a chance to run */
1000 mlog(ML_ERROR, "link to %u went down?: %d\n", res->owner, ret);
1001 msleep(500);
1002 goto recheck;
1003 }
1004 ret = 0;
6714d8e8
KH		 1005 goto leave;
1006 }
1007 spin_unlock(&res->spinlock);
1008
1009 spin_lock(&mle->spinlock);
1010 m = mle->master;
1011 map_changed = (memcmp(mle->vote_map, mle->node_map,
1012 sizeof(mle->vote_map)) != 0);
1013 voting_done = (memcmp(mle->vote_map, mle->response_map,
1014 sizeof(mle->vote_map)) == 0);
1015
1016 /* restart if we hit any errors */
1017 if (map_changed) {
1018 int b;
1019 mlog(0, "%s: %.*s: node map changed, restarting\n",
1020 dlm->name, res->lockname.len, res->lockname.name);
1021 ret = dlm_restart_lock_mastery(dlm, res, mle, *blocked);
1022 b = (mle->type == DLM_MLE_BLOCK);
1023 if ((*blocked && !b) || (!*blocked && b)) {
1024 mlog(0, "%s:%.*s: status change: old=%d new=%d\n",
1025 dlm->name, res->lockname.len, res->lockname.name,
1026 *blocked, b);
1027 *blocked = b;
1028 }
1029 spin_unlock(&mle->spinlock);
1030 if (ret < 0) {
1031 mlog_errno(ret);
1032 goto leave;
1033 }
1034 mlog(0, "%s:%.*s: restart lock mastery succeeded, "
1035 "rechecking now\n", dlm->name, res->lockname.len,
1036 res->lockname.name);
1037 goto recheck;
aa852354
KH		 1038 } else {
1039 if (!voting_done) {
1040 mlog(0, "map not changed and voting not done "
1041 "for %s:%.*s\n", dlm->name, res->lockname.len,
1042 res->lockname.name);
1043 }
6714d8e8
KH		 1044 }
1045
1046 if (m != O2NM_MAX_NODES) {
1047 /* another node has done an assert!
1048 * all done! */
1049 sleep = 0;
1050 } else {
1051 sleep = 1;
1052 /* have all nodes responded? */
1053 if (voting_done && !*blocked) {
1054 bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
1055 if (dlm->node_num <= bit) {
1056 /* my node number is lowest.
1057 * now tell other nodes that I am
1058 * mastering this. */
1059 mle->master = dlm->node_num;
1060 assert = 1;
1061 sleep = 0;
1062 }
1063 /* if voting is done, but we have not received
1064 * an assert master yet, we must sleep */
1065 }
1066 }
1067
1068 spin_unlock(&mle->spinlock);
1069
1070 /* sleep if we haven't finished voting yet */
1071 if (sleep) {
1072 unsigned long timeo = msecs_to_jiffies(DLM_MASTERY_TIMEOUT_MS);
1073
1074 /*
1075 if (atomic_read(&mle->mle_refs.refcount) < 2)
1076 mlog(ML_ERROR, "mle (%p) refs=%d, name=%.*s\n", mle,
1077 atomic_read(&mle->mle_refs.refcount),
1078 res->lockname.len, res->lockname.name);
1079 */
1080 atomic_set(&mle->woken, 0);
1081 (void)wait_event_timeout(mle->wq,
1082 (atomic_read(&mle->woken) == 1),
1083 timeo);
1084 if (res->owner == O2NM_MAX_NODES) {
1085 mlog(0, "waiting again\n");
1086 goto recheck;
1087 }
1088 mlog(0, "done waiting, master is %u\n", res->owner);
1089 ret = 0;
1090 goto leave;
1091 }
1092
1093 ret = 0; /* done */
1094 if (assert) {
1095 m = dlm->node_num;
1096 mlog(0, "about to master %.*s here, this=%u\n",
1097 res->lockname.len, res->lockname.name, m);
1098 ret = dlm_do_assert_master(dlm, res->lockname.name,
1099 res->lockname.len, mle->vote_map, 0);
1100 if (ret) {
1101 /* This is a failure in the network path,
1102 * not in the response to the assert_master
1103 * (any nonzero response is a BUG on this node).
1104 * Most likely a socket just got disconnected
1105 * due to node death. */
1106 mlog_errno(ret);
1107 }
1108 /* no longer need to restart lock mastery.
1109 * all living nodes have been contacted. */
1110 ret = 0;
1111 }
1112
1113 /* set the lockres owner */
1114 spin_lock(&res->spinlock);
1115 dlm_change_lockres_owner(dlm, res, m);
1116 spin_unlock(&res->spinlock);
1117
1118leave:
1119 return ret;
1120}
1121
1122struct dlm_bitmap_diff_iter
1123{
1124 int curnode;
1125 unsigned long *orig_bm;
1126 unsigned long *cur_bm;
1127 unsigned long diff_bm[BITS_TO_LONGS(O2NM_MAX_NODES)];
1128};
1129
1130enum dlm_node_state_change
1131{
1132 NODE_DOWN = -1,
1133 NODE_NO_CHANGE = 0,
1134 NODE_UP
1135};
1136
1137static void dlm_bitmap_diff_iter_init(struct dlm_bitmap_diff_iter *iter,
1138 unsigned long *orig_bm,
1139 unsigned long *cur_bm)
1140{
1141 unsigned long p1, p2;
1142 int i;
1143
1144 iter->curnode = -1;
1145 iter->orig_bm = orig_bm;
1146 iter->cur_bm = cur_bm;
1147
1148 for (i = 0; i < BITS_TO_LONGS(O2NM_MAX_NODES); i++) {
1149 p1 = *(iter->orig_bm + i);
1150 p2 = *(iter->cur_bm + i);
1151 iter->diff_bm[i] = (p1 & ~p2) | (p2 & ~p1);
1152 }
1153}
1154
1155static int dlm_bitmap_diff_iter_next(struct dlm_bitmap_diff_iter *iter,
1156 enum dlm_node_state_change *state)
1157{
1158 int bit;
1159
1160 if (iter->curnode >= O2NM_MAX_NODES)
1161 return -ENOENT;
1162
1163 bit = find_next_bit(iter->diff_bm, O2NM_MAX_NODES,
1164 iter->curnode+1);
1165 if (bit >= O2NM_MAX_NODES) {
1166 iter->curnode = O2NM_MAX_NODES;
1167 return -ENOENT;
1168 }
1169
1170 /* if it was there in the original then this node died */
1171 if (test_bit(bit, iter->orig_bm))
1172 *state = NODE_DOWN;
1173 else
1174 *state = NODE_UP;
1175
1176 iter->curnode = bit;
1177 return bit;
1178}
1179
1180
1181static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
1182 struct dlm_lock_resource *res,
1183 struct dlm_master_list_entry *mle,
1184 int blocked)
1185{
1186 struct dlm_bitmap_diff_iter bdi;
1187 enum dlm_node_state_change sc;
1188 int node;
1189 int ret = 0;
1190
1191 mlog(0, "something happened such that the "
1192 "master process may need to be restarted!\n");
1193
1194 assert_spin_locked(&mle->spinlock);
1195
1196 dlm_bitmap_diff_iter_init(&bdi, mle->vote_map, mle->node_map);
1197 node = dlm_bitmap_diff_iter_next(&bdi, &sc);
1198 while (node >= 0) {
1199 if (sc == NODE_UP) {
e2faea4c
KH		 1200 /* a node came up. clear any old vote from
1201 * the response map and set it in the vote map
1202 * then restart the mastery. */
1203 mlog(ML_NOTICE, "node %d up while restarting\n", node);
6714d8e8
KH		 1204
1205 /* redo the master request, but only for the new node */
1206 mlog(0, "sending request to new node\n");
1207 clear_bit(node, mle->response_map);
1208 set_bit(node, mle->vote_map);
1209 } else {
1210 mlog(ML_ERROR, "node down! %d\n", node);
1211
1212 /* if the node wasn't involved in mastery skip it,
1213 * but clear it out from the maps so that it will
1214 * not affect mastery of this lockres */
1215 clear_bit(node, mle->response_map);
1216 clear_bit(node, mle->vote_map);
1217 if (!test_bit(node, mle->maybe_map))
1218 goto next;
1219
1220 /* if we're already blocked on lock mastery, and the
1221 * dead node wasn't the expected master, or there is
1222 * another node in the maybe_map, keep waiting */
1223 if (blocked) {
1224 int lowest = find_next_bit(mle->maybe_map,
1225 O2NM_MAX_NODES, 0);
1226
1227 /* act like it was never there */
1228 clear_bit(node, mle->maybe_map);
1229
1230 if (node != lowest)
1231 goto next;
1232
1233 mlog(ML_ERROR, "expected master %u died while "
1234 "this node was blocked waiting on it!\n",
1235 node);
1236 lowest = find_next_bit(mle->maybe_map,
1237 O2NM_MAX_NODES,
1238 lowest+1);
1239 if (lowest < O2NM_MAX_NODES) {
1240 mlog(0, "still blocked. waiting "
1241 "on %u now\n", lowest);
1242 goto next;
1243 }
1244
1245 /* mle is an MLE_BLOCK, but there is now
1246 * nothing left to block on. we need to return
1247 * all the way back out and try again with
1248 * an MLE_MASTER. dlm_do_local_recovery_cleanup
1249 * has already run, so the mle refcount is ok */
1250 mlog(0, "no longer blocking. we can "
1251 "try to master this here\n");
1252 mle->type = DLM_MLE_MASTER;
1253 memset(mle->maybe_map, 0,
1254 sizeof(mle->maybe_map));
1255 memset(mle->response_map, 0,
1256 sizeof(mle->maybe_map));
1257 memcpy(mle->vote_map, mle->node_map,
1258 sizeof(mle->node_map));
1259 mle->u.res = res;
1260 set_bit(dlm->node_num, mle->maybe_map);
1261
1262 ret = -EAGAIN;
1263 goto next;
1264 }
1265
1266 clear_bit(node, mle->maybe_map);
1267 if (node > dlm->node_num)
1268 goto next;
1269
1270 mlog(0, "dead node in map!\n");
1271 /* yuck. go back and re-contact all nodes
1272 * in the vote_map, removing this node. */
1273 memset(mle->response_map, 0,
1274 sizeof(mle->response_map));
1275 }
1276 ret = -EAGAIN;
1277next:
1278 node = dlm_bitmap_diff_iter_next(&bdi, &sc);
1279 }
1280 return ret;
1281}
1282
1283
1284/*
1285 * DLM_MASTER_REQUEST_MSG
1286 *
1287 * returns: 0 on success,
1288 * -errno on a network error
1289 *
1290 * on error, the caller should assume the target node is "dead"
1291 *
1292 */
1293
1294static int dlm_do_master_request(struct dlm_master_list_entry *mle, int to)
1295{
1296 struct dlm_ctxt *dlm = mle->dlm;
1297 struct dlm_master_request request;
1298 int ret, response=0, resend;
1299
1300 memset(&request, 0, sizeof(request));
1301 request.node_idx = dlm->node_num;
1302
1303 BUG_ON(mle->type == DLM_MLE_MIGRATION);
1304
1305 if (mle->type != DLM_MLE_MASTER) {
1306 request.namelen = mle->u.name.len;
1307 memcpy(request.name, mle->u.name.name, request.namelen);
1308 } else {
1309 request.namelen = mle->u.res->lockname.len;
1310 memcpy(request.name, mle->u.res->lockname.name,
1311 request.namelen);
1312 }
1313
1314again:
1315 ret = o2net_send_message(DLM_MASTER_REQUEST_MSG, dlm->key, &request,
1316 sizeof(request), to, &response);
1317 if (ret < 0) {
1318 if (ret == -ESRCH) {
1319 /* should never happen */
1320 mlog(ML_ERROR, "TCP stack not ready!\n");
1321 BUG();
1322 } else if (ret == -EINVAL) {
1323 mlog(ML_ERROR, "bad args passed to o2net!\n");
1324 BUG();
1325 } else if (ret == -ENOMEM) {
1326 mlog(ML_ERROR, "out of memory while trying to send "
1327 "network message! retrying\n");
1328 /* this is totally crude */
1329 msleep(50);
1330 goto again;
1331 } else if (!dlm_is_host_down(ret)) {
1332 /* not a network error. bad. */
1333 mlog_errno(ret);
1334 mlog(ML_ERROR, "unhandled error!");
1335 BUG();
1336 }
1337 /* all other errors should be network errors,
1338 * and likely indicate node death */
1339 mlog(ML_ERROR, "link to %d went down!\n", to);
1340 goto out;
1341 }
1342
1343 ret = 0;
1344 resend = 0;
1345 spin_lock(&mle->spinlock);
1346 switch (response) {
1347 case DLM_MASTER_RESP_YES:
1348 set_bit(to, mle->response_map);
1349 mlog(0, "node %u is the master, response=YES\n", to);
1350 mle->master = to;
1351 break;
1352 case DLM_MASTER_RESP_NO:
1353 mlog(0, "node %u not master, response=NO\n", to);
1354 set_bit(to, mle->response_map);
1355 break;
1356 case DLM_MASTER_RESP_MAYBE:
1357 mlog(0, "node %u not master, response=MAYBE\n", to);
1358 set_bit(to, mle->response_map);
1359 set_bit(to, mle->maybe_map);
1360 break;
1361 case DLM_MASTER_RESP_ERROR:
1362 mlog(0, "node %u hit an error, resending\n", to);
1363 resend = 1;
1364 response = 0;
1365 break;
1366 default:
1367 mlog(ML_ERROR, "bad response! %u\n", response);
1368 BUG();
1369 }
1370 spin_unlock(&mle->spinlock);
1371 if (resend) {
1372 /* this is also totally crude */
1373 msleep(50);
1374 goto again;
1375 }
1376
1377out:
1378 return ret;
1379}
1380
1381/*
1382 * locks that can be taken here:
1383 * dlm->spinlock
1384 * res->spinlock
1385 * mle->spinlock
1386 * dlm->master_list
1387 *
1388 * if possible, TRIM THIS DOWN!!!
1389 */
1390int dlm_master_request_handler(struct o2net_msg *msg, u32 len, void *data)
1391{
1392 u8 response = DLM_MASTER_RESP_MAYBE;
1393 struct dlm_ctxt *dlm = data;
9c6510a5 1394 struct dlm_lock_resource *res = NULL;
6714d8e8
KH		 1395 struct dlm_master_request *request = (struct dlm_master_request *) msg->buf;
1396 struct dlm_master_list_entry *mle = NULL, *tmpmle = NULL;
1397 char *name;
a3d33291 1398 unsigned int namelen, hash;
6714d8e8
KH		 1399 int found, ret;
1400 int set_maybe;
9c6510a5 1401 int dispatch_assert = 0;
6714d8e8
KH		 1402
1403 if (!dlm_grab(dlm))
1404 return DLM_MASTER_RESP_NO;
1405
1406 if (!dlm_domain_fully_joined(dlm)) {
1407 response = DLM_MASTER_RESP_NO;
1408 goto send_response;
1409 }
1410
1411 name = request->name;
1412 namelen = request->namelen;
a3d33291 1413 hash = dlm_lockid_hash(name, namelen);
6714d8e8
KH		 1414
1415 if (namelen > DLM_LOCKID_NAME_MAX) {
1416 response = DLM_IVBUFLEN;
1417 goto send_response;
1418 }
1419
1420way_up_top:
1421 spin_lock(&dlm->spinlock);
a3d33291 1422 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
6714d8e8
KH		 1423 if (res) {
1424 spin_unlock(&dlm->spinlock);
1425
1426 /* take care of the easy cases up front */
1427 spin_lock(&res->spinlock);
1428 if (res->state & DLM_LOCK_RES_RECOVERING) {
1429 spin_unlock(&res->spinlock);
1430 mlog(0, "returning DLM_MASTER_RESP_ERROR since res is "
1431 "being recovered\n");
1432 response = DLM_MASTER_RESP_ERROR;
1433 if (mle)
1434 kmem_cache_free(dlm_mle_cache, mle);
1435 goto send_response;
1436 }
1437
1438 if (res->owner == dlm->node_num) {
6714d8e8
KH		 1439 spin_unlock(&res->spinlock);
1440 // mlog(0, "this node is the master\n");
1441 response = DLM_MASTER_RESP_YES;
1442 if (mle)
1443 kmem_cache_free(dlm_mle_cache, mle);
1444
1445 /* this node is the owner.
1446 * there is some extra work that needs to
1447 * happen now. the requesting node has
1448 * caused all nodes up to this one to
1449 * create mles. this node now needs to
1450 * go back and clean those up. */
9c6510a5 1451 dispatch_assert = 1;
6714d8e8
KH		 1452 goto send_response;
1453 } else if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1454 spin_unlock(&res->spinlock);
1455 // mlog(0, "node %u is the master\n", res->owner);
1456 response = DLM_MASTER_RESP_NO;
1457 if (mle)
1458 kmem_cache_free(dlm_mle_cache, mle);
1459 goto send_response;
1460 }
1461
1462 /* ok, there is no owner. either this node is
1463 * being blocked, or it is actively trying to
1464 * master this lock. */
1465 if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
1466 mlog(ML_ERROR, "lock with no owner should be "
1467 "in-progress!\n");
1468 BUG();
1469 }
1470
1471 // mlog(0, "lockres is in progress...\n");
1472 spin_lock(&dlm->master_lock);
1473 found = dlm_find_mle(dlm, &tmpmle, name, namelen);
1474 if (!found) {
1475 mlog(ML_ERROR, "no mle found for this lock!\n");
1476 BUG();
1477 }
1478 set_maybe = 1;
1479 spin_lock(&tmpmle->spinlock);
1480 if (tmpmle->type == DLM_MLE_BLOCK) {
1481 // mlog(0, "this node is waiting for "
1482 // "lockres to be mastered\n");
1483 response = DLM_MASTER_RESP_NO;
1484 } else if (tmpmle->type == DLM_MLE_MIGRATION) {
1485 mlog(0, "node %u is master, but trying to migrate to "
1486 "node %u.\n", tmpmle->master, tmpmle->new_master);
1487 if (tmpmle->master == dlm->node_num) {
1488 response = DLM_MASTER_RESP_YES;
1489 mlog(ML_ERROR, "no owner on lockres, but this "
1490 "node is trying to migrate it to %u?!\n",
1491 tmpmle->new_master);
1492 BUG();
1493 } else {
1494 /* the real master can respond on its own */
1495 response = DLM_MASTER_RESP_NO;
1496 }
1497 } else if (tmpmle->master != DLM_LOCK_RES_OWNER_UNKNOWN) {
1498 set_maybe = 0;
9c6510a5 1499 if (tmpmle->master == dlm->node_num) {
6714d8e8 1500 response = DLM_MASTER_RESP_YES;
9c6510a5
KH		 1501 /* this node will be the owner.
1502 * go back and clean the mles on any
1503 * other nodes */
1504 dispatch_assert = 1;
1505 } else
6714d8e8
KH		 1506 response = DLM_MASTER_RESP_NO;
1507 } else {
1508 // mlog(0, "this node is attempting to "
1509 // "master lockres\n");
1510 response = DLM_MASTER_RESP_MAYBE;
1511 }
1512 if (set_maybe)
1513 set_bit(request->node_idx, tmpmle->maybe_map);
1514 spin_unlock(&tmpmle->spinlock);
1515
1516 spin_unlock(&dlm->master_lock);
1517 spin_unlock(&res->spinlock);
1518
1519 /* keep the mle attached to heartbeat events */
1520 dlm_put_mle(tmpmle);
1521 if (mle)
1522 kmem_cache_free(dlm_mle_cache, mle);
1523 goto send_response;
1524 }
1525
1526 /*
1527 * lockres doesn't exist on this node
1528 * if there is an MLE_BLOCK, return NO
1529 * if there is an MLE_MASTER, return MAYBE
1530 * otherwise, add an MLE_BLOCK, return NO
1531 */
1532 spin_lock(&dlm->master_lock);
1533 found = dlm_find_mle(dlm, &tmpmle, name, namelen);
1534 if (!found) {
1535 /* this lockid has never been seen on this node yet */
1536 // mlog(0, "no mle found\n");
1537 if (!mle) {
1538 spin_unlock(&dlm->master_lock);
1539 spin_unlock(&dlm->spinlock);
1540
1541 mle = (struct dlm_master_list_entry *)
1542 kmem_cache_alloc(dlm_mle_cache, GFP_KERNEL);
1543 if (!mle) {
6714d8e8 1544 response = DLM_MASTER_RESP_ERROR;
9c6510a5 1545 mlog_errno(-ENOMEM);
6714d8e8
KH		 1546 goto send_response;
1547 }
6714d8e8
KH		 1548 goto way_up_top;
1549 }
1550
1551 // mlog(0, "this is second time thru, already allocated, "
1552 // "add the block.\n");
41b8c8a1 1553 dlm_init_mle(mle, DLM_MLE_BLOCK, dlm, NULL, name, namelen);
6714d8e8
KH		 1554 set_bit(request->node_idx, mle->maybe_map);
1555 list_add(&mle->list, &dlm->master_list);
1556 response = DLM_MASTER_RESP_NO;
1557 } else {
1558 // mlog(0, "mle was found\n");
1559 set_maybe = 1;
1560 spin_lock(&tmpmle->spinlock);
9c6510a5
KH		 1561 if (tmpmle->master == dlm->node_num) {
1562 mlog(ML_ERROR, "no lockres, but an mle with this node as master!\n");
1563 BUG();
1564 }
6714d8e8
KH		 1565 if (tmpmle->type == DLM_MLE_BLOCK)
1566 response = DLM_MASTER_RESP_NO;
1567 else if (tmpmle->type == DLM_MLE_MIGRATION) {
1568 mlog(0, "migration mle was found (%u->%u)\n",
1569 tmpmle->master, tmpmle->new_master);
6714d8e8
KH		 1570 /* real master can respond on its own */
1571 response = DLM_MASTER_RESP_NO;
9c6510a5
KH		 1572 } else
1573 response = DLM_MASTER_RESP_MAYBE;
6714d8e8
KH		 1574 if (set_maybe)
1575 set_bit(request->node_idx, tmpmle->maybe_map);
1576 spin_unlock(&tmpmle->spinlock);
1577 }
1578 spin_unlock(&dlm->master_lock);
1579 spin_unlock(&dlm->spinlock);
1580
1581 if (found) {
1582 /* keep the mle attached to heartbeat events */
1583 dlm_put_mle(tmpmle);
1584 }
1585send_response:
9c6510a5
KH		 1586
1587 if (dispatch_assert) {
1588 if (response != DLM_MASTER_RESP_YES)
1589 mlog(ML_ERROR, "invalid response %d\n", response);
1590 if (!res) {
1591 mlog(ML_ERROR, "bad lockres while trying to assert!\n");
1592 BUG();
1593 }
1594 mlog(0, "%u is the owner of %.*s, cleaning everyone else\n",
1595 dlm->node_num, res->lockname.len, res->lockname.name);
1596 ret = dlm_dispatch_assert_master(dlm, res, 0, request->node_idx,
1597 DLM_ASSERT_MASTER_MLE_CLEANUP);
1598 if (ret < 0) {
1599 mlog(ML_ERROR, "failed to dispatch assert master work\n");
1600 response = DLM_MASTER_RESP_ERROR;
1601 }
1602 }
1603
6714d8e8
KH		 1604 dlm_put(dlm);
1605 return response;
1606}
1607
1608/*
1609 * DLM_ASSERT_MASTER_MSG
1610 */
1611
1612
1613/*
1614 * NOTE: this can be used for debugging
1615 * can periodically run all locks owned by this node
1616 * and re-assert across the cluster...
1617 */
1618static int dlm_do_assert_master(struct dlm_ctxt *dlm, const char *lockname,
1619 unsigned int namelen, void *nodemap,
1620 u32 flags)
1621{
1622 struct dlm_assert_master assert;
1623 int to, tmpret;
1624 struct dlm_node_iter iter;
1625 int ret = 0;
9c6510a5 1626 int reassert;
6714d8e8
KH		 1627
1628 BUG_ON(namelen > O2NM_MAX_NAME_LEN);
9c6510a5
KH		 1629again:
1630 reassert = 0;
6714d8e8
KH		 1631
1632 /* note that if this nodemap is empty, it returns 0 */
1633 dlm_node_iter_init(nodemap, &iter);
1634 while ((to = dlm_node_iter_next(&iter)) >= 0) {
1635 int r = 0;
a9ee4c8a
KH		 1636 struct dlm_master_list_entry *mle = NULL;
1637
6714d8e8
KH		 1638 mlog(0, "sending assert master to %d (%.*s)\n", to,
1639 namelen, lockname);
1640 memset(&assert, 0, sizeof(assert));
1641 assert.node_idx = dlm->node_num;
1642 assert.namelen = namelen;
1643 memcpy(assert.name, lockname, namelen);
1644 assert.flags = cpu_to_be32(flags);
1645
1646 tmpret = o2net_send_message(DLM_ASSERT_MASTER_MSG, dlm->key,
1647 &assert, sizeof(assert), to, &r);
1648 if (tmpret < 0) {
1649 mlog(ML_ERROR, "assert_master returned %d!\n", tmpret);
1650 if (!dlm_is_host_down(tmpret)) {
1651 mlog(ML_ERROR, "unhandled error!\n");
1652 BUG();
1653 }
1654 /* a node died. finish out the rest of the nodes. */
1655 mlog(ML_ERROR, "link to %d went down!\n", to);
1656 /* any nonzero status return will do */
1657 ret = tmpret;
1658 } else if (r < 0) {
1659 /* ok, something horribly messed. kill thyself. */
1660 mlog(ML_ERROR,"during assert master of %.*s to %u, "
1661 "got %d.\n", namelen, lockname, to, r);
a9ee4c8a
KH		 1662 spin_lock(&dlm->spinlock);
1663 spin_lock(&dlm->master_lock);
1664 if (dlm_find_mle(dlm, &mle, (char *)lockname,
1665 namelen)) {
1666 dlm_print_one_mle(mle);
1667 __dlm_put_mle(mle);
1668 }
1669 spin_unlock(&dlm->master_lock);
1670 spin_unlock(&dlm->spinlock);
6714d8e8 1671 BUG();
9c6510a5
KH		 1672 } else if (r == EAGAIN) {
1673 mlog(0, "%.*s: node %u create mles on other "
1674 "nodes and requests a re-assert\n",
1675 namelen, lockname, to);
1676 reassert = 1;
6714d8e8
KH		 1677 }
1678 }
1679
9c6510a5
KH		 1680 if (reassert)
1681 goto again;
1682
6714d8e8
KH		 1683 return ret;
1684}
1685
1686/*
1687 * locks that can be taken here:
1688 * dlm->spinlock
1689 * res->spinlock
1690 * mle->spinlock
1691 * dlm->master_list
1692 *
1693 * if possible, TRIM THIS DOWN!!!
1694 */
1695int dlm_assert_master_handler(struct o2net_msg *msg, u32 len, void *data)
1696{
1697 struct dlm_ctxt *dlm = data;
1698 struct dlm_master_list_entry *mle = NULL;
1699 struct dlm_assert_master *assert = (struct dlm_assert_master *)msg->buf;
1700 struct dlm_lock_resource *res = NULL;
1701 char *name;
a3d33291 1702 unsigned int namelen, hash;
6714d8e8 1703 u32 flags;
9c6510a5
KH		 1704 int master_request = 0;
1705 int ret = 0;
6714d8e8
KH		 1706
1707 if (!dlm_grab(dlm))
1708 return 0;
1709
1710 name = assert->name;
1711 namelen = assert->namelen;
a3d33291 1712 hash = dlm_lockid_hash(name, namelen);
6714d8e8
KH		 1713 flags = be32_to_cpu(assert->flags);
1714
1715 if (namelen > DLM_LOCKID_NAME_MAX) {
1716 mlog(ML_ERROR, "Invalid name length!");
1717 goto done;
1718 }
1719
1720 spin_lock(&dlm->spinlock);
1721
1722 if (flags)
1723 mlog(0, "assert_master with flags: %u\n", flags);
1724
1725 /* find the MLE */
1726 spin_lock(&dlm->master_lock);
1727 if (!dlm_find_mle(dlm, &mle, name, namelen)) {
1728 /* not an error, could be master just re-asserting */
1729 mlog(0, "just got an assert_master from %u, but no "
1730 "MLE for it! (%.*s)\n", assert->node_idx,
1731 namelen, name);
1732 } else {
1733 int bit = find_next_bit (mle->maybe_map, O2NM_MAX_NODES, 0);
1734 if (bit >= O2NM_MAX_NODES) {
1735 /* not necessarily an error, though less likely.
1736 * could be master just re-asserting. */
aa852354 1737 mlog(0, "no bits set in the maybe_map, but %u "
6714d8e8
KH		 1738 "is asserting! (%.*s)\n", assert->node_idx,
1739 namelen, name);
1740 } else if (bit != assert->node_idx) {
1741 if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
1742 mlog(0, "master %u was found, %u should "
1743 "back off\n", assert->node_idx, bit);
1744 } else {
1745 /* with the fix for bug 569, a higher node
1746 * number winning the mastery will respond
1747 * YES to mastery requests, but this node
1748 * had no way of knowing. let it pass. */
aa852354 1749 mlog(0, "%u is the lowest node, "
6714d8e8
KH		 1750 "%u is asserting. (%.*s) %u must "
1751 "have begun after %u won.\n", bit,
1752 assert->node_idx, namelen, name, bit,
1753 assert->node_idx);
1754 }
1755 }
2d1a868c
KH		 1756 if (mle->type == DLM_MLE_MIGRATION) {
1757 if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
1758 mlog(0, "%s:%.*s: got cleanup assert"
1759 " from %u for migration\n",
1760 dlm->name, namelen, name,
1761 assert->node_idx);
1762 } else if (!(flags & DLM_ASSERT_MASTER_FINISH_MIGRATION)) {
1763 mlog(0, "%s:%.*s: got unrelated assert"
1764 " from %u for migration, ignoring\n",
1765 dlm->name, namelen, name,
1766 assert->node_idx);
1767 __dlm_put_mle(mle);
1768 spin_unlock(&dlm->master_lock);
1769 spin_unlock(&dlm->spinlock);
1770 goto done;
1771 }
1772 }
6714d8e8
KH		 1773 }
1774 spin_unlock(&dlm->master_lock);
1775
1776 /* ok everything checks out with the MLE
1777 * now check to see if there is a lockres */
a3d33291 1778 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
6714d8e8
KH		 1779 if (res) {
1780 spin_lock(&res->spinlock);
1781 if (res->state & DLM_LOCK_RES_RECOVERING) {
1782 mlog(ML_ERROR, "%u asserting but %.*s is "
1783 "RECOVERING!\n", assert->node_idx, namelen, name);
1784 goto kill;
1785 }
1786 if (!mle) {
dc2ed195
KH		 1787 if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN &&
1788 res->owner != assert->node_idx) {
6714d8e8
KH		 1789 mlog(ML_ERROR, "assert_master from "
1790 "%u, but current owner is "
1791 "%u! (%.*s)\n",
1792 assert->node_idx, res->owner,
1793 namelen, name);
1794 goto kill;
1795 }
1796 } else if (mle->type != DLM_MLE_MIGRATION) {
1797 if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1798 /* owner is just re-asserting */
1799 if (res->owner == assert->node_idx) {
1800 mlog(0, "owner %u re-asserting on "
1801 "lock %.*s\n", assert->node_idx,
1802 namelen, name);
1803 goto ok;
1804 }
1805 mlog(ML_ERROR, "got assert_master from "
1806 "node %u, but %u is the owner! "
1807 "(%.*s)\n", assert->node_idx,
1808 res->owner, namelen, name);
1809 goto kill;
1810 }
1811 if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
1812 mlog(ML_ERROR, "got assert from %u, but lock "
1813 "with no owner should be "
1814 "in-progress! (%.*s)\n",
1815 assert->node_idx,
1816 namelen, name);
1817 goto kill;
1818 }
1819 } else /* mle->type == DLM_MLE_MIGRATION */ {
1820 /* should only be getting an assert from new master */
1821 if (assert->node_idx != mle->new_master) {
1822 mlog(ML_ERROR, "got assert from %u, but "
1823 "new master is %u, and old master "
1824 "was %u (%.*s)\n",
1825 assert->node_idx, mle->new_master,
1826 mle->master, namelen, name);
1827 goto kill;
1828 }
1829
1830 }
1831ok:
1832 spin_unlock(&res->spinlock);
1833 }
1834 spin_unlock(&dlm->spinlock);
1835
1836 // mlog(0, "woo! got an assert_master from node %u!\n",
1837 // assert->node_idx);
1838 if (mle) {
9c6510a5
KH		 1839 int extra_ref = 0;
1840 int nn = -1;
a2bf0477 1841 int rr, err = 0;
6714d8e8
KH		 1842
1843 spin_lock(&mle->spinlock);
9c6510a5
KH		 1844 if (mle->type == DLM_MLE_BLOCK || mle->type == DLM_MLE_MIGRATION)
1845 extra_ref = 1;
1846 else {
1847 /* MASTER mle: if any bits set in the response map
1848 * then the calling node needs to re-assert to clear
1849 * up nodes that this node contacted */
1850 while ((nn = find_next_bit (mle->response_map, O2NM_MAX_NODES,
1851 nn+1)) < O2NM_MAX_NODES) {
1852 if (nn != dlm->node_num && nn != assert->node_idx)
1853 master_request = 1;
1854 }
1855 }
6714d8e8
KH		 1856 mle->master = assert->node_idx;
1857 atomic_set(&mle->woken, 1);
1858 wake_up(&mle->wq);
1859 spin_unlock(&mle->spinlock);
1860
a2bf0477 1861 if (res) {
6714d8e8 1862 spin_lock(&res->spinlock);
a2bf0477
KH		 1863 if (mle->type == DLM_MLE_MIGRATION) {
1864 mlog(0, "finishing off migration of lockres %.*s, "
1865 "from %u to %u\n",
1866 res->lockname.len, res->lockname.name,
1867 dlm->node_num, mle->new_master);
1868 res->state &= ~DLM_LOCK_RES_MIGRATING;
1869 dlm_change_lockres_owner(dlm, res, mle->new_master);
1870 BUG_ON(res->state & DLM_LOCK_RES_DIRTY);
1871 } else {
1872 dlm_change_lockres_owner(dlm, res, mle->master);
1873 }
6714d8e8
KH		 1874 spin_unlock(&res->spinlock);
1875 }
a2bf0477
KH		 1876
1877 /* master is known, detach if not already detached.
1878 * ensures that only one assert_master call will happen
1879 * on this mle. */
1880 spin_lock(&dlm->spinlock);
1881 spin_lock(&dlm->master_lock);
1882
1883 rr = atomic_read(&mle->mle_refs.refcount);
1884 if (mle->inuse > 0) {
1885 if (extra_ref && rr < 3)
1886 err = 1;
1887 else if (!extra_ref && rr < 2)
1888 err = 1;
1889 } else {
1890 if (extra_ref && rr < 2)
1891 err = 1;
1892 else if (!extra_ref && rr < 1)
1893 err = 1;
1894 }
1895 if (err) {
1896 mlog(ML_ERROR, "%s:%.*s: got assert master from %u "
1897 "that will mess up this node, refs=%d, extra=%d, "
1898 "inuse=%d\n", dlm->name, namelen, name,
1899 assert->node_idx, rr, extra_ref, mle->inuse);
1900 dlm_print_one_mle(mle);
1901 }
1902 list_del_init(&mle->list);
1903 __dlm_mle_detach_hb_events(dlm, mle);
1904 __dlm_put_mle(mle);
6714d8e8
KH		 1905 if (extra_ref) {
1906 /* the assert master message now balances the extra
1907 * ref given by the master / migration request message.
1908 * if this is the last put, it will be removed
1909 * from the list. */
a2bf0477
KH		 1910 __dlm_put_mle(mle);
1911 }
1912 spin_unlock(&dlm->master_lock);
1913 spin_unlock(&dlm->spinlock);
1914 } else if (res) {
1915 if (res->owner != assert->node_idx) {
1916 mlog(0, "assert_master from %u, but current "
1917 "owner is %u (%.*s), no mle\n", assert->node_idx,
1918 res->owner, namelen, name);
6714d8e8
KH		 1919 }
1920 }
1921
1922done:
9c6510a5 1923 ret = 0;
6714d8e8
KH		 1924 if (res)
1925 dlm_lockres_put(res);
1926 dlm_put(dlm);
9c6510a5
KH		 1927 if (master_request) {
1928 mlog(0, "need to tell master to reassert\n");
1929 ret = EAGAIN; // positive. negative would shoot down the node.
1930 }
1931 return ret;
6714d8e8
KH		 1932
1933kill:
1934 /* kill the caller! */
a9ee4c8a
KH		 1935 mlog(ML_ERROR, "Bad message received from another node. Dumping state "
1936 "and killing the other node now! This node is OK and can continue.\n");
1937 __dlm_print_one_lock_resource(res);
6714d8e8
KH		 1938 spin_unlock(&res->spinlock);
1939 spin_unlock(&dlm->spinlock);
1940 dlm_lockres_put(res);
6714d8e8
KH		 1941 dlm_put(dlm);
1942 return -EINVAL;
1943}
1944
1945int dlm_dispatch_assert_master(struct dlm_ctxt *dlm,
1946 struct dlm_lock_resource *res,
1947 int ignore_higher, u8 request_from, u32 flags)
1948{
1949 struct dlm_work_item *item;
1950 item = kcalloc(1, sizeof(*item), GFP_KERNEL);
1951 if (!item)
1952 return -ENOMEM;
1953
1954
1955 /* queue up work for dlm_assert_master_worker */
1956 dlm_grab(dlm); /* get an extra ref for the work item */
1957 dlm_init_work_item(dlm, item, dlm_assert_master_worker, NULL);
1958 item->u.am.lockres = res; /* already have a ref */
1959 /* can optionally ignore node numbers higher than this node */
1960 item->u.am.ignore_higher = ignore_higher;
1961 item->u.am.request_from = request_from;
1962 item->u.am.flags = flags;
1963
9c6510a5
KH		 1964 if (ignore_higher)
1965 mlog(0, "IGNORE HIGHER: %.*s\n", res->lockname.len,
1966 res->lockname.name);
1967
6714d8e8
KH		 1968 spin_lock(&dlm->work_lock);
1969 list_add_tail(&item->list, &dlm->work_list);
1970 spin_unlock(&dlm->work_lock);
1971
1972 schedule_work(&dlm->dispatched_work);
1973 return 0;
1974}
1975
1976static void dlm_assert_master_worker(struct dlm_work_item *item, void *data)
1977{
1978 struct dlm_ctxt *dlm = data;
1979 int ret = 0;
1980 struct dlm_lock_resource *res;
1981 unsigned long nodemap[BITS_TO_LONGS(O2NM_MAX_NODES)];
1982 int ignore_higher;
1983 int bit;
1984 u8 request_from;
1985 u32 flags;
1986
1987 dlm = item->dlm;
1988 res = item->u.am.lockres;
1989 ignore_higher = item->u.am.ignore_higher;
1990 request_from = item->u.am.request_from;
1991 flags = item->u.am.flags;
1992
1993 spin_lock(&dlm->spinlock);
1994 memcpy(nodemap, dlm->domain_map, sizeof(nodemap));
1995 spin_unlock(&dlm->spinlock);
1996
1997 clear_bit(dlm->node_num, nodemap);
1998 if (ignore_higher) {
1999 /* if is this just to clear up mles for nodes below
2000 * this node, do not send the message to the original
2001 * caller or any node number higher than this */
2002 clear_bit(request_from, nodemap);
2003 bit = dlm->node_num;
2004 while (1) {
2005 bit = find_next_bit(nodemap, O2NM_MAX_NODES,
2006 bit+1);
2007 if (bit >= O2NM_MAX_NODES)
2008 break;
2009 clear_bit(bit, nodemap);
2010 }
2011 }
2012
2013 /* this call now finishes out the nodemap
2014 * even if one or more nodes die */
2015 mlog(0, "worker about to master %.*s here, this=%u\n",
2016 res->lockname.len, res->lockname.name, dlm->node_num);
2017 ret = dlm_do_assert_master(dlm, res->lockname.name,
2018 res->lockname.len,
2019 nodemap, flags);
2020 if (ret < 0) {
2021 /* no need to restart, we are done */
2022 mlog_errno(ret);
2023 }
2024
2025 dlm_lockres_put(res);
2026
2027 mlog(0, "finished with dlm_assert_master_worker\n");
2028}
2029
c03872f5
KH		 2030/* SPECIAL CASE for the $RECOVERY lock used by the recovery thread.
2031 * We cannot wait for node recovery to complete to begin mastering this
2032 * lockres because this lockres is used to kick off recovery! ;-)
2033 * So, do a pre-check on all living nodes to see if any of those nodes
2034 * think that $RECOVERY is currently mastered by a dead node. If so,
2035 * we wait a short time to allow that node to get notified by its own
2036 * heartbeat stack, then check again. All $RECOVERY lock resources
2037 * mastered by dead nodes are purged when the hearbeat callback is
2038 * fired, so we can know for sure that it is safe to continue once
2039 * the node returns a live node or no node. */
2040static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
2041 struct dlm_lock_resource *res)
2042{
2043 struct dlm_node_iter iter;
2044 int nodenum;
2045 int ret = 0;
2046 u8 master = DLM_LOCK_RES_OWNER_UNKNOWN;
2047
2048 spin_lock(&dlm->spinlock);
2049 dlm_node_iter_init(dlm->domain_map, &iter);
2050 spin_unlock(&dlm->spinlock);
2051
2052 while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
2053 /* do not send to self */
2054 if (nodenum == dlm->node_num)
2055 continue;
2056 ret = dlm_do_master_requery(dlm, res, nodenum, &master);
2057 if (ret < 0) {
2058 mlog_errno(ret);
2059 if (!dlm_is_host_down(ret))
2060 BUG();
2061 /* host is down, so answer for that node would be
2062 * DLM_LOCK_RES_OWNER_UNKNOWN. continue. */
2063 }
2064
2065 if (master != DLM_LOCK_RES_OWNER_UNKNOWN) {
2066 /* check to see if this master is in the recovery map */
2067 spin_lock(&dlm->spinlock);
2068 if (test_bit(master, dlm->recovery_map)) {
2069 mlog(ML_NOTICE, "%s: node %u has not seen "
2070 "node %u go down yet, and thinks the "
2071 "dead node is mastering the recovery "
2072 "lock. must wait.\n", dlm->name,
2073 nodenum, master);
2074 ret = -EAGAIN;
2075 }
2076 spin_unlock(&dlm->spinlock);
2077 mlog(0, "%s: reco lock master is %u\n", dlm->name,
2078 master);
2079 break;
2080 }
2081 }
2082 return ret;
2083}
2084
6714d8e8
KH		 2085
2086/*
2087 * DLM_MIGRATE_LOCKRES
2088 */
2089
2090
2091int dlm_migrate_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
2092 u8 target)
2093{
2094 struct dlm_master_list_entry *mle = NULL;
2095 struct dlm_master_list_entry *oldmle = NULL;
2096 struct dlm_migratable_lockres *mres = NULL;
2097 int ret = -EINVAL;
2098 const char *name;
2099 unsigned int namelen;
2100 int mle_added = 0;
2101 struct list_head *queue, *iter;
2102 int i;
2103 struct dlm_lock *lock;
2104 int empty = 1;
2105
2106 if (!dlm_grab(dlm))
2107 return -EINVAL;
2108
2109 name = res->lockname.name;
2110 namelen = res->lockname.len;
2111
2112 mlog(0, "migrating %.*s to %u\n", namelen, name, target);
2113
2114 /*
2115 * ensure this lockres is a proper candidate for migration
2116 */
2117 spin_lock(&res->spinlock);
2118 if (res->owner == DLM_LOCK_RES_OWNER_UNKNOWN) {
2119 mlog(0, "cannot migrate lockres with unknown owner!\n");
2120 spin_unlock(&res->spinlock);
2121 goto leave;
2122 }
2123 if (res->owner != dlm->node_num) {
2124 mlog(0, "cannot migrate lockres this node doesn't own!\n");
2125 spin_unlock(&res->spinlock);
2126 goto leave;
2127 }
2128 mlog(0, "checking queues...\n");
2129 queue = &res->granted;
2130 for (i=0; i<3; i++) {
2131 list_for_each(iter, queue) {
2132 lock = list_entry (iter, struct dlm_lock, list);
2133 empty = 0;
2134 if (lock->ml.node == dlm->node_num) {
2135 mlog(0, "found a lock owned by this node "
2136 "still on the %s queue! will not "
2137 "migrate this lockres\n",
2138 i==0 ? "granted" :
2139 (i==1 ? "converting" : "blocked"));
2140 spin_unlock(&res->spinlock);
2141 ret = -ENOTEMPTY;
2142 goto leave;
2143 }
2144 }
2145 queue++;
2146 }
2147 mlog(0, "all locks on this lockres are nonlocal. continuing\n");
2148 spin_unlock(&res->spinlock);
2149
2150 /* no work to do */
2151 if (empty) {
2152 mlog(0, "no locks were found on this lockres! done!\n");
2153 ret = 0;
2154 goto leave;
2155 }
2156
2157 /*
2158 * preallocate up front
2159 * if this fails, abort
2160 */
2161
2162 ret = -ENOMEM;
2163 mres = (struct dlm_migratable_lockres *) __get_free_page(GFP_KERNEL);
2164 if (!mres) {
2165 mlog_errno(ret);
2166 goto leave;
2167 }
2168
2169 mle = (struct dlm_master_list_entry *) kmem_cache_alloc(dlm_mle_cache,
2170 GFP_KERNEL);
2171 if (!mle) {
2172 mlog_errno(ret);
2173 goto leave;
2174 }
2175 ret = 0;
2176
2177 /*
2178 * find a node to migrate the lockres to
2179 */
2180
2181 mlog(0, "picking a migration node\n");
2182 spin_lock(&dlm->spinlock);
2183 /* pick a new node */
2184 if (!test_bit(target, dlm->domain_map) ||
2185 target >= O2NM_MAX_NODES) {
2186 target = dlm_pick_migration_target(dlm, res);
2187 }
2188 mlog(0, "node %u chosen for migration\n", target);
2189
2190 if (target >= O2NM_MAX_NODES ||
2191 !test_bit(target, dlm->domain_map)) {
2192 /* target chosen is not alive */
2193 ret = -EINVAL;
2194 }
2195
2196 if (ret) {
2197 spin_unlock(&dlm->spinlock);
2198 goto fail;
2199 }
2200
2201 mlog(0, "continuing with target = %u\n", target);
2202
2203 /*
2204 * clear any existing master requests and
2205 * add the migration mle to the list
2206 */
2207 spin_lock(&dlm->master_lock);
2208 ret = dlm_add_migration_mle(dlm, res, mle, &oldmle, name,
2209 namelen, target, dlm->node_num);
2210 spin_unlock(&dlm->master_lock);
2211 spin_unlock(&dlm->spinlock);
2212
2213 if (ret == -EEXIST) {
2214 mlog(0, "another process is already migrating it\n");
2215 goto fail;
2216 }
2217 mle_added = 1;
2218
2219 /*
2220 * set the MIGRATING flag and flush asts
2221 * if we fail after this we need to re-dirty the lockres
2222 */
2223 if (dlm_mark_lockres_migrating(dlm, res, target) < 0) {
2224 mlog(ML_ERROR, "tried to migrate %.*s to %u, but "
2225 "the target went down.\n", res->lockname.len,
2226 res->lockname.name, target);
2227 spin_lock(&res->spinlock);
2228 res->state &= ~DLM_LOCK_RES_MIGRATING;
2229 spin_unlock(&res->spinlock);
2230 ret = -EINVAL;
2231 }
2232
2233fail:
2234 if (oldmle) {
2235 /* master is known, detach if not already detached */
2236 dlm_mle_detach_hb_events(dlm, oldmle);
2237 dlm_put_mle(oldmle);
2238 }
2239
2240 if (ret < 0) {
2241 if (mle_added) {
2242 dlm_mle_detach_hb_events(dlm, mle);
2243 dlm_put_mle(mle);
2244 } else if (mle) {
2245 kmem_cache_free(dlm_mle_cache, mle);
2246 }
2247 goto leave;
2248 }
2249
2250 /*
2251 * at this point, we have a migration target, an mle
2252 * in the master list, and the MIGRATING flag set on
2253 * the lockres
2254 */
2255
2256
2257 /* get an extra reference on the mle.
2258 * otherwise the assert_master from the new
2259 * master will destroy this.
2260 * also, make sure that all callers of dlm_get_mle
2261 * take both dlm->spinlock and dlm->master_lock */
2262 spin_lock(&dlm->spinlock);
2263 spin_lock(&dlm->master_lock);
a2bf0477 2264 dlm_get_mle_inuse(mle);
6714d8e8
KH		 2265 spin_unlock(&dlm->master_lock);
2266 spin_unlock(&dlm->spinlock);
2267
2268 /* notify new node and send all lock state */
2269 /* call send_one_lockres with migration flag.
2270 * this serves as notice to the target node that a
2271 * migration is starting. */
2272 ret = dlm_send_one_lockres(dlm, res, mres, target,
2273 DLM_MRES_MIGRATION);
2274
2275 if (ret < 0) {
2276 mlog(0, "migration to node %u failed with %d\n",
2277 target, ret);
2278 /* migration failed, detach and clean up mle */
2279 dlm_mle_detach_hb_events(dlm, mle);
2280 dlm_put_mle(mle);
a2bf0477
KH		 2281 dlm_put_mle_inuse(mle);
2282 spin_lock(&res->spinlock);
2283 res->state &= ~DLM_LOCK_RES_MIGRATING;
2284 spin_unlock(&res->spinlock);
6714d8e8
KH		 2285 goto leave;
2286 }
2287
2288 /* at this point, the target sends a message to all nodes,
2289 * (using dlm_do_migrate_request). this node is skipped since
2290 * we had to put an mle in the list to begin the process. this
2291 * node now waits for target to do an assert master. this node
2292 * will be the last one notified, ensuring that the migration
2293 * is complete everywhere. if the target dies while this is
2294 * going on, some nodes could potentially see the target as the
2295 * master, so it is important that my recovery finds the migration
2296 * mle and sets the master to UNKNONWN. */
2297
2298
2299 /* wait for new node to assert master */
2300 while (1) {
2301 ret = wait_event_interruptible_timeout(mle->wq,
2302 (atomic_read(&mle->woken) == 1),
2303 msecs_to_jiffies(5000));
2304
2305 if (ret >= 0) {
2306 if (atomic_read(&mle->woken) == 1 ||
2307 res->owner == target)
2308 break;
2309
2310 mlog(0, "timed out during migration\n");
e2faea4c
KH		 2311 /* avoid hang during shutdown when migrating lockres
2312 * to a node which also goes down */
2313 if (dlm_is_node_dead(dlm, target)) {
aa852354
KH		 2314 mlog(0, "%s:%.*s: expected migration "
2315 "target %u is no longer up, restarting\n",
e2faea4c
KH		 2316 dlm->name, res->lockname.len,
2317 res->lockname.name, target);
2318 ret = -ERESTARTSYS;
2319 }
6714d8e8
KH		 2320 }
2321 if (ret == -ERESTARTSYS) {
2322 /* migration failed, detach and clean up mle */
2323 dlm_mle_detach_hb_events(dlm, mle);
2324 dlm_put_mle(mle);
a2bf0477
KH		 2325 dlm_put_mle_inuse(mle);
2326 spin_lock(&res->spinlock);
2327 res->state &= ~DLM_LOCK_RES_MIGRATING;
2328 spin_unlock(&res->spinlock);
6714d8e8
KH		 2329 goto leave;
2330 }
2331 /* TODO: if node died: stop, clean up, return error */
2332 }
2333
2334 /* all done, set the owner, clear the flag */
2335 spin_lock(&res->spinlock);
2336 dlm_set_lockres_owner(dlm, res, target);
2337 res->state &= ~DLM_LOCK_RES_MIGRATING;
2338 dlm_remove_nonlocal_locks(dlm, res);
2339 spin_unlock(&res->spinlock);
2340 wake_up(&res->wq);
2341
2342 /* master is known, detach if not already detached */
2343 dlm_mle_detach_hb_events(dlm, mle);
a2bf0477 2344 dlm_put_mle_inuse(mle);
6714d8e8
KH		 2345 ret = 0;
2346
2347 dlm_lockres_calc_usage(dlm, res);
2348
2349leave:
2350 /* re-dirty the lockres if we failed */
2351 if (ret < 0)
2352 dlm_kick_thread(dlm, res);
2353
2354 /* TODO: cleanup */
2355 if (mres)
2356 free_page((unsigned long)mres);
2357
2358 dlm_put(dlm);
2359
2360 mlog(0, "returning %d\n", ret);
2361 return ret;
2362}
2363EXPORT_SYMBOL_GPL(dlm_migrate_lockres);
2364
2365int dlm_lock_basts_flushed(struct dlm_ctxt *dlm, struct dlm_lock *lock)
2366{
2367 int ret;
2368 spin_lock(&dlm->ast_lock);
2369 spin_lock(&lock->spinlock);
2370 ret = (list_empty(&lock->bast_list) && !lock->bast_pending);
2371 spin_unlock(&lock->spinlock);
2372 spin_unlock(&dlm->ast_lock);
2373 return ret;
2374}
2375
2376static int dlm_migration_can_proceed(struct dlm_ctxt *dlm,
2377 struct dlm_lock_resource *res,
2378 u8 mig_target)
2379{
2380 int can_proceed;
2381 spin_lock(&res->spinlock);
2382 can_proceed = !!(res->state & DLM_LOCK_RES_MIGRATING);
2383 spin_unlock(&res->spinlock);
2384
2385 /* target has died, so make the caller break out of the
2386 * wait_event, but caller must recheck the domain_map */
2387 spin_lock(&dlm->spinlock);
2388 if (!test_bit(mig_target, dlm->domain_map))
2389 can_proceed = 1;
2390 spin_unlock(&dlm->spinlock);
2391 return can_proceed;
2392}
2393
2394int dlm_lockres_is_dirty(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
2395{
2396 int ret;
2397 spin_lock(&res->spinlock);
2398 ret = !!(res->state & DLM_LOCK_RES_DIRTY);
2399 spin_unlock(&res->spinlock);
2400 return ret;
2401}
2402
2403
2404static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
2405 struct dlm_lock_resource *res,
2406 u8 target)
2407{
2408 int ret = 0;
2409
2410 mlog(0, "dlm_mark_lockres_migrating: %.*s, from %u to %u\n",
2411 res->lockname.len, res->lockname.name, dlm->node_num,
2412 target);
2413 /* need to set MIGRATING flag on lockres. this is done by
2414 * ensuring that all asts have been flushed for this lockres. */
2415 spin_lock(&res->spinlock);
2416 BUG_ON(res->migration_pending);
2417 res->migration_pending = 1;
2418 /* strategy is to reserve an extra ast then release
2419 * it below, letting the release do all of the work */
2420 __dlm_lockres_reserve_ast(res);
2421 spin_unlock(&res->spinlock);
2422
2423 /* now flush all the pending asts.. hang out for a bit */
2424 dlm_kick_thread(dlm, res);
2425 wait_event(dlm->ast_wq, !dlm_lockres_is_dirty(dlm, res));
2426 dlm_lockres_release_ast(dlm, res);
2427
2428 mlog(0, "about to wait on migration_wq, dirty=%s\n",
2429 res->state & DLM_LOCK_RES_DIRTY ? "yes" : "no");
2430 /* if the extra ref we just put was the final one, this
2431 * will pass thru immediately. otherwise, we need to wait
2432 * for the last ast to finish. */
2433again:
2434 ret = wait_event_interruptible_timeout(dlm->migration_wq,
2435 dlm_migration_can_proceed(dlm, res, target),
2436 msecs_to_jiffies(1000));
2437 if (ret < 0) {
2438 mlog(0, "woken again: migrating? %s, dead? %s\n",
2439 res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
2440 test_bit(target, dlm->domain_map) ? "no":"yes");
2441 } else {
2442 mlog(0, "all is well: migrating? %s, dead? %s\n",
2443 res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
2444 test_bit(target, dlm->domain_map) ? "no":"yes");
2445 }
2446 if (!dlm_migration_can_proceed(dlm, res, target)) {
2447 mlog(0, "trying again...\n");
2448 goto again;
2449 }
2450
2451 /* did the target go down or die? */
2452 spin_lock(&dlm->spinlock);
2453 if (!test_bit(target, dlm->domain_map)) {
2454 mlog(ML_ERROR, "aha. migration target %u just went down\n",
2455 target);
2456 ret = -EHOSTDOWN;
2457 }
2458 spin_unlock(&dlm->spinlock);
2459
2460 /*
2461 * at this point:
2462 *
2463 * o the DLM_LOCK_RES_MIGRATING flag is set
2464 * o there are no pending asts on this lockres
2465 * o all processes trying to reserve an ast on this
2466 * lockres must wait for the MIGRATING flag to clear
2467 */
2468 return ret;
2469}
2470
2471/* last step in the migration process.
2472 * original master calls this to free all of the dlm_lock
2473 * structures that used to be for other nodes. */
2474static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
2475 struct dlm_lock_resource *res)
2476{
2477 struct list_head *iter, *iter2;
2478 struct list_head *queue = &res->granted;
2479 int i;
2480 struct dlm_lock *lock;
2481
2482 assert_spin_locked(&res->spinlock);
2483
2484 BUG_ON(res->owner == dlm->node_num);
2485
2486 for (i=0; i<3; i++) {
2487 list_for_each_safe(iter, iter2, queue) {
2488 lock = list_entry (iter, struct dlm_lock, list);
2489 if (lock->ml.node != dlm->node_num) {
2490 mlog(0, "putting lock for node %u\n",
2491 lock->ml.node);
2492 /* be extra careful */
2493 BUG_ON(!list_empty(&lock->ast_list));
2494 BUG_ON(!list_empty(&lock->bast_list));
2495 BUG_ON(lock->ast_pending);
2496 BUG_ON(lock->bast_pending);
2497 list_del_init(&lock->list);
2498 dlm_lock_put(lock);
2499 }
2500 }
2501 queue++;
2502 }
2503}
2504
2505/* for now this is not too intelligent. we will
2506 * need stats to make this do the right thing.
2507 * this just finds the first lock on one of the
2508 * queues and uses that node as the target. */
2509static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
2510 struct dlm_lock_resource *res)
2511{
2512 int i;
2513 struct list_head *queue = &res->granted;
2514 struct list_head *iter;
2515 struct dlm_lock *lock;
2516 int nodenum;
2517
2518 assert_spin_locked(&dlm->spinlock);
2519
2520 spin_lock(&res->spinlock);
2521 for (i=0; i<3; i++) {
2522 list_for_each(iter, queue) {
2523 /* up to the caller to make sure this node
2524 * is alive */
2525 lock = list_entry (iter, struct dlm_lock, list);
2526 if (lock->ml.node != dlm->node_num) {
2527 spin_unlock(&res->spinlock);
2528 return lock->ml.node;
2529 }
2530 }
2531 queue++;
2532 }
2533 spin_unlock(&res->spinlock);
2534 mlog(0, "have not found a suitable target yet! checking domain map\n");
2535
2536 /* ok now we're getting desperate. pick anyone alive. */
2537 nodenum = -1;
2538 while (1) {
2539 nodenum = find_next_bit(dlm->domain_map,
2540 O2NM_MAX_NODES, nodenum+1);
2541 mlog(0, "found %d in domain map\n", nodenum);
2542 if (nodenum >= O2NM_MAX_NODES)
2543 break;
2544 if (nodenum != dlm->node_num) {
2545 mlog(0, "picking %d\n", nodenum);
2546 return nodenum;
2547 }
2548 }
2549
2550 mlog(0, "giving up. no master to migrate to\n");
2551 return DLM_LOCK_RES_OWNER_UNKNOWN;
2552}
2553
2554
2555
2556/* this is called by the new master once all lockres
2557 * data has been received */
2558static int dlm_do_migrate_request(struct dlm_ctxt *dlm,
2559 struct dlm_lock_resource *res,
2560 u8 master, u8 new_master,
2561 struct dlm_node_iter *iter)
2562{
2563 struct dlm_migrate_request migrate;
2564 int ret, status = 0;
2565 int nodenum;
2566
2567 memset(&migrate, 0, sizeof(migrate));
2568 migrate.namelen = res->lockname.len;
2569 memcpy(migrate.name, res->lockname.name, migrate.namelen);
2570 migrate.new_master = new_master;
2571 migrate.master = master;
2572
2573 ret = 0;
2574
2575 /* send message to all nodes, except the master and myself */
2576 while ((nodenum = dlm_node_iter_next(iter)) >= 0) {
2577 if (nodenum == master ||
2578 nodenum == new_master)
2579 continue;
2580
2581 ret = o2net_send_message(DLM_MIGRATE_REQUEST_MSG, dlm->key,
2582 &migrate, sizeof(migrate), nodenum,
2583 &status);
2584 if (ret < 0)
2585 mlog_errno(ret);
2586 else if (status < 0) {
2587 mlog(0, "migrate request (node %u) returned %d!\n",
2588 nodenum, status);
2589 ret = status;
2590 }
2591 }
2592
2593 if (ret < 0)
2594 mlog_errno(ret);
2595
2596 mlog(0, "returning ret=%d\n", ret);
2597 return ret;
2598}
2599
2600
2601/* if there is an existing mle for this lockres, we now know who the master is.
2602 * (the one who sent us *this* message) we can clear it up right away.
2603 * since the process that put the mle on the list still has a reference to it,
2604 * we can unhash it now, set the master and wake the process. as a result,
2605 * we will have no mle in the list to start with. now we can add an mle for
2606 * the migration and this should be the only one found for those scanning the
2607 * list. */
2608int dlm_migrate_request_handler(struct o2net_msg *msg, u32 len, void *data)
2609{
2610 struct dlm_ctxt *dlm = data;
2611 struct dlm_lock_resource *res = NULL;
2612 struct dlm_migrate_request *migrate = (struct dlm_migrate_request *) msg->buf;
2613 struct dlm_master_list_entry *mle = NULL, *oldmle = NULL;
2614 const char *name;
a3d33291 2615 unsigned int namelen, hash;
6714d8e8
KH		 2616 int ret = 0;
2617
2618 if (!dlm_grab(dlm))
2619 return -EINVAL;
2620
2621 name = migrate->name;
2622 namelen = migrate->namelen;
a3d33291 2623 hash = dlm_lockid_hash(name, namelen);
6714d8e8
KH		 2624
2625 /* preallocate.. if this fails, abort */
2626 mle = (struct dlm_master_list_entry *) kmem_cache_alloc(dlm_mle_cache,
2627 GFP_KERNEL);
2628
2629 if (!mle) {
2630 ret = -ENOMEM;
2631 goto leave;
2632 }
2633
2634 /* check for pre-existing lock */
2635 spin_lock(&dlm->spinlock);
a3d33291 2636 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
6714d8e8
KH		 2637 spin_lock(&dlm->master_lock);
2638
2639 if (res) {
2640 spin_lock(&res->spinlock);
2641 if (res->state & DLM_LOCK_RES_RECOVERING) {
2642 /* if all is working ok, this can only mean that we got
2643 * a migrate request from a node that we now see as
2644 * dead. what can we do here? drop it to the floor? */
2645 spin_unlock(&res->spinlock);
2646 mlog(ML_ERROR, "Got a migrate request, but the "
2647 "lockres is marked as recovering!");
2648 kmem_cache_free(dlm_mle_cache, mle);
2649 ret = -EINVAL; /* need a better solution */
2650 goto unlock;
2651 }
2652 res->state |= DLM_LOCK_RES_MIGRATING;
2653 spin_unlock(&res->spinlock);
2654 }
2655
2656 /* ignore status. only nonzero status would BUG. */
2657 ret = dlm_add_migration_mle(dlm, res, mle, &oldmle,
2658 name, namelen,
2659 migrate->new_master,
2660 migrate->master);
2661
2662unlock:
2663 spin_unlock(&dlm->master_lock);
2664 spin_unlock(&dlm->spinlock);
2665
2666 if (oldmle) {
2667 /* master is known, detach if not already detached */
2668 dlm_mle_detach_hb_events(dlm, oldmle);
2669 dlm_put_mle(oldmle);
2670 }
2671
2672 if (res)
2673 dlm_lockres_put(res);
2674leave:
2675 dlm_put(dlm);
2676 return ret;
2677}
2678
2679/* must be holding dlm->spinlock and dlm->master_lock
2680 * when adding a migration mle, we can clear any other mles
2681 * in the master list because we know with certainty that
2682 * the master is "master". so we remove any old mle from
2683 * the list after setting it's master field, and then add
2684 * the new migration mle. this way we can hold with the rule
2685 * of having only one mle for a given lock name at all times. */
2686static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
2687 struct dlm_lock_resource *res,
2688 struct dlm_master_list_entry *mle,
2689 struct dlm_master_list_entry **oldmle,
2690 const char *name, unsigned int namelen,
2691 u8 new_master, u8 master)
2692{
2693 int found;
2694 int ret = 0;
2695
2696 *oldmle = NULL;
2697
2698 mlog_entry_void();
2699
2700 assert_spin_locked(&dlm->spinlock);
2701 assert_spin_locked(&dlm->master_lock);
2702
2703 /* caller is responsible for any ref taken here on oldmle */
2704 found = dlm_find_mle(dlm, oldmle, (char *)name, namelen);
2705 if (found) {
2706 struct dlm_master_list_entry *tmp = *oldmle;
2707 spin_lock(&tmp->spinlock);
2708 if (tmp->type == DLM_MLE_MIGRATION) {
2709 if (master == dlm->node_num) {
2710 /* ah another process raced me to it */
2711 mlog(0, "tried to migrate %.*s, but some "
2712 "process beat me to it\n",
2713 namelen, name);
2714 ret = -EEXIST;
2715 } else {
2716 /* bad. 2 NODES are trying to migrate! */
2717 mlog(ML_ERROR, "migration error mle: "
2718 "master=%u new_master=%u // request: "
2719 "master=%u new_master=%u // "
2720 "lockres=%.*s\n",
2721 tmp->master, tmp->new_master,
2722 master, new_master,
2723 namelen, name);
2724 BUG();
2725 }
2726 } else {
2727 /* this is essentially what assert_master does */
2728 tmp->master = master;
2729 atomic_set(&tmp->woken, 1);
2730 wake_up(&tmp->wq);
2731 /* remove it from the list so that only one
2732 * mle will be found */
2733 list_del_init(&tmp->list);
da01ad05 2734 __dlm_mle_detach_hb_events(dlm, mle);
6714d8e8
KH		 2735 }
2736 spin_unlock(&tmp->spinlock);
2737 }
2738
2739 /* now add a migration mle to the tail of the list */
2740 dlm_init_mle(mle, DLM_MLE_MIGRATION, dlm, res, name, namelen);
2741 mle->new_master = new_master;
2742 mle->master = master;
2743 /* do this for consistency with other mle types */
2744 set_bit(new_master, mle->maybe_map);
2745 list_add(&mle->list, &dlm->master_list);
2746
2747 return ret;
2748}
2749
2750
2751void dlm_clean_master_list(struct dlm_ctxt *dlm, u8 dead_node)
2752{
2753 struct list_head *iter, *iter2;
2754 struct dlm_master_list_entry *mle;
2755 struct dlm_lock_resource *res;
a3d33291 2756 unsigned int hash;
6714d8e8
KH		 2757
2758 mlog_entry("dlm=%s, dead node=%u\n", dlm->name, dead_node);
2759top:
2760 assert_spin_locked(&dlm->spinlock);
2761
2762 /* clean the master list */
2763 spin_lock(&dlm->master_lock);
2764 list_for_each_safe(iter, iter2, &dlm->master_list) {
2765 mle = list_entry(iter, struct dlm_master_list_entry, list);
2766
2767 BUG_ON(mle->type != DLM_MLE_BLOCK &&
2768 mle->type != DLM_MLE_MASTER &&
2769 mle->type != DLM_MLE_MIGRATION);
2770
2771 /* MASTER mles are initiated locally. the waiting
2772 * process will notice the node map change
2773 * shortly. let that happen as normal. */
2774 if (mle->type == DLM_MLE_MASTER)
2775 continue;
2776
2777
2778 /* BLOCK mles are initiated by other nodes.
2779 * need to clean up if the dead node would have
2780 * been the master. */
2781 if (mle->type == DLM_MLE_BLOCK) {
2782 int bit;
2783
2784 spin_lock(&mle->spinlock);
2785 bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
2786 if (bit != dead_node) {
2787 mlog(0, "mle found, but dead node %u would "
2788 "not have been master\n", dead_node);
2789 spin_unlock(&mle->spinlock);
2790 } else {
2791 /* must drop the refcount by one since the
2792 * assert_master will never arrive. this
2793 * may result in the mle being unlinked and
2794 * freed, but there may still be a process
2795 * waiting in the dlmlock path which is fine. */
2796 mlog(ML_ERROR, "node %u was expected master\n",
2797 dead_node);
2798 atomic_set(&mle->woken, 1);
2799 spin_unlock(&mle->spinlock);
2800 wake_up(&mle->wq);
f671c09b
KH		 2801 /* do not need events any longer, so detach
2802 * from heartbeat */
2803 __dlm_mle_detach_hb_events(dlm, mle);
6714d8e8
KH		 2804 __dlm_put_mle(mle);
2805 }
2806 continue;
2807 }
2808
2809 /* everything else is a MIGRATION mle */
2810
2811 /* the rule for MIGRATION mles is that the master
2812 * becomes UNKNOWN if *either* the original or
2813 * the new master dies. all UNKNOWN lockreses
2814 * are sent to whichever node becomes the recovery
2815 * master. the new master is responsible for
2816 * determining if there is still a master for
2817 * this lockres, or if he needs to take over
2818 * mastery. either way, this node should expect
2819 * another message to resolve this. */
2820 if (mle->master != dead_node &&
2821 mle->new_master != dead_node)
2822 continue;
2823
2824 /* if we have reached this point, this mle needs to
2825 * be removed from the list and freed. */
2826
2827 /* remove from the list early. NOTE: unlinking
2828 * list_head while in list_for_each_safe */
da01ad05 2829 __dlm_mle_detach_hb_events(dlm, mle);
6714d8e8
KH		 2830 spin_lock(&mle->spinlock);
2831 list_del_init(&mle->list);
2832 atomic_set(&mle->woken, 1);
2833 spin_unlock(&mle->spinlock);
2834 wake_up(&mle->wq);
2835
aa852354
KH		 2836 mlog(0, "%s: node %u died during migration from "
2837 "%u to %u!\n", dlm->name, dead_node,
6714d8e8
KH		 2838 mle->master, mle->new_master);
2839 /* if there is a lockres associated with this
2840 * mle, find it and set its owner to UNKNOWN */
a3d33291 2841 hash = dlm_lockid_hash(mle->u.name.name, mle->u.name.len);
6714d8e8 2842 res = __dlm_lookup_lockres(dlm, mle->u.name.name,
a3d33291 2843 mle->u.name.len, hash);
6714d8e8
KH		 2844 if (res) {
2845 /* unfortunately if we hit this rare case, our
2846 * lock ordering is messed. we need to drop
2847 * the master lock so that we can take the
2848 * lockres lock, meaning that we will have to
2849 * restart from the head of list. */
2850 spin_unlock(&dlm->master_lock);
2851
2852 /* move lockres onto recovery list */
2853 spin_lock(&res->spinlock);
2854 dlm_set_lockres_owner(dlm, res,
2855 DLM_LOCK_RES_OWNER_UNKNOWN);
2856 dlm_move_lockres_to_recovery_list(dlm, res);
2857 spin_unlock(&res->spinlock);
2858 dlm_lockres_put(res);
2859
f671c09b
KH		 2860 /* about to get rid of mle, detach from heartbeat */
2861 __dlm_mle_detach_hb_events(dlm, mle);
2862
6714d8e8
KH		 2863 /* dump the mle */
2864 spin_lock(&dlm->master_lock);
2865 __dlm_put_mle(mle);
2866 spin_unlock(&dlm->master_lock);
2867
2868 /* restart */
2869 goto top;
2870 }
2871
2872 /* this may be the last reference */
2873 __dlm_put_mle(mle);
2874 }
2875 spin_unlock(&dlm->master_lock);
2876}
2877
2878
2879int dlm_finish_migration(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
2880 u8 old_master)
2881{
2882 struct dlm_node_iter iter;
2883 int ret = 0;
2884
2885 spin_lock(&dlm->spinlock);
2886 dlm_node_iter_init(dlm->domain_map, &iter);
2887 clear_bit(old_master, iter.node_map);
2888 clear_bit(dlm->node_num, iter.node_map);
2889 spin_unlock(&dlm->spinlock);
2890
2891 mlog(0, "now time to do a migrate request to other nodes\n");
2892 ret = dlm_do_migrate_request(dlm, res, old_master,
2893 dlm->node_num, &iter);
2894 if (ret < 0) {
2895 mlog_errno(ret);
2896 goto leave;
2897 }
2898
2899 mlog(0, "doing assert master of %.*s to all except the original node\n",
2900 res->lockname.len, res->lockname.name);
2901 /* this call now finishes out the nodemap
2902 * even if one or more nodes die */
2903 ret = dlm_do_assert_master(dlm, res->lockname.name,
2904 res->lockname.len, iter.node_map,
2905 DLM_ASSERT_MASTER_FINISH_MIGRATION);
2906 if (ret < 0) {
2907 /* no longer need to retry. all living nodes contacted. */
2908 mlog_errno(ret);
2909 ret = 0;
2910 }
2911
2912 memset(iter.node_map, 0, sizeof(iter.node_map));
2913 set_bit(old_master, iter.node_map);
2914 mlog(0, "doing assert master of %.*s back to %u\n",
2915 res->lockname.len, res->lockname.name, old_master);
2916 ret = dlm_do_assert_master(dlm, res->lockname.name,
2917 res->lockname.len, iter.node_map,
2918 DLM_ASSERT_MASTER_FINISH_MIGRATION);
2919 if (ret < 0) {
2920 mlog(0, "assert master to original master failed "
2921 "with %d.\n", ret);
2922 /* the only nonzero status here would be because of
2923 * a dead original node. we're done. */
2924 ret = 0;
2925 }
2926
2927 /* all done, set the owner, clear the flag */
2928 spin_lock(&res->spinlock);
2929 dlm_set_lockres_owner(dlm, res, dlm->node_num);
2930 res->state &= ~DLM_LOCK_RES_MIGRATING;
2931 spin_unlock(&res->spinlock);
2932 /* re-dirty it on the new master */
2933 dlm_kick_thread(dlm, res);
2934 wake_up(&res->wq);
2935leave:
2936 return ret;
2937}
2938
2939/*
2940 * LOCKRES AST REFCOUNT
2941 * this is integral to migration
2942 */
2943
2944/* for future intent to call an ast, reserve one ahead of time.
2945 * this should be called only after waiting on the lockres
2946 * with dlm_wait_on_lockres, and while still holding the
2947 * spinlock after the call. */
2948void __dlm_lockres_reserve_ast(struct dlm_lock_resource *res)
2949{
2950 assert_spin_locked(&res->spinlock);
2951 if (res->state & DLM_LOCK_RES_MIGRATING) {
2952 __dlm_print_one_lock_resource(res);
2953 }
2954 BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
2955
2956 atomic_inc(&res->asts_reserved);
2957}
2958
2959/*
2960 * used to drop the reserved ast, either because it went unused,
2961 * or because the ast/bast was actually called.
2962 *
2963 * also, if there is a pending migration on this lockres,
2964 * and this was the last pending ast on the lockres,
2965 * atomically set the MIGRATING flag before we drop the lock.
2966 * this is how we ensure that migration can proceed with no
2967 * asts in progress. note that it is ok if the state of the
2968 * queues is such that a lock should be granted in the future
2969 * or that a bast should be fired, because the new master will
2970 * shuffle the lists on this lockres as soon as it is migrated.
2971 */
2972void dlm_lockres_release_ast(struct dlm_ctxt *dlm,
2973 struct dlm_lock_resource *res)
2974{
2975 if (!atomic_dec_and_lock(&res->asts_reserved, &res->spinlock))
2976 return;
2977
2978 if (!res->migration_pending) {
2979 spin_unlock(&res->spinlock);
2980 return;
2981 }
2982
2983 BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
2984 res->migration_pending = 0;
2985 res->state |= DLM_LOCK_RES_MIGRATING;
2986 spin_unlock(&res->spinlock);
2987 wake_up(&res->wq);
2988 wake_up(&dlm->migration_wq);
2989}
Linux 6.x block layer and io_uring tree(s)