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ocfs2: continue recovery when a dead node is encountered
[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);
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
e7e69eb3 870redo_request:
c03872f5
KH		 871 while (wait_on_recovery) {
872 /* any cluster changes that occurred after dropping the
873 * dlm spinlock would be detectable be a change on the mle,
874 * so we only need to clear out the recovery map once. */
875 if (dlm_is_recovery_lock(lockid, namelen)) {
876 mlog(ML_NOTICE, "%s: recovery map is not empty, but "
877 "must master $RECOVERY lock now\n", dlm->name);
878 if (!dlm_pre_master_reco_lockres(dlm, res))
879 wait_on_recovery = 0;
880 else {
881 mlog(0, "%s: waiting 500ms for heartbeat state "
882 "change\n", dlm->name);
883 msleep(500);
884 }
885 continue;
886 }
887
888 dlm_kick_recovery_thread(dlm);
aa087b84 889 msleep(1000);
c03872f5
KH		 890 dlm_wait_for_recovery(dlm);
891
892 spin_lock(&dlm->spinlock);
893 bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
894 if (bit < O2NM_MAX_NODES) {
895 mlog(ML_NOTICE, "%s:%.*s: at least one node (%d) to"
896 "recover before lock mastery can begin\n",
897 dlm->name, namelen, (char *)lockid, bit);
898 wait_on_recovery = 1;
899 } else
900 wait_on_recovery = 0;
901 spin_unlock(&dlm->spinlock);
902 }
903
6714d8e8
KH		 904 /* must wait for lock to be mastered elsewhere */
905 if (blocked)
906 goto wait;
907
6714d8e8
KH		 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) {
e7e69eb3 932 wait_on_recovery = 1;
6714d8e8
KH		 933 mlog(0, "%s:%.*s: node map changed, redo the "
934 "master request now, blocked=%d\n",
935 dlm->name, res->lockname.len,
936 res->lockname.name, blocked);
937 if (++tries > 20) {
938 mlog(ML_ERROR, "%s:%.*s: spinning on "
939 "dlm_wait_for_lock_mastery, blocked=%d\n",
940 dlm->name, res->lockname.len,
941 res->lockname.name, blocked);
942 dlm_print_one_lock_resource(res);
943 /* dlm_print_one_mle(mle); */
944 tries = 0;
945 }
946 goto redo_request;
947 }
948
949 mlog(0, "lockres mastered by %u\n", res->owner);
950 /* make sure we never continue without this */
951 BUG_ON(res->owner == O2NM_MAX_NODES);
952
953 /* master is known, detach if not already detached */
954 dlm_mle_detach_hb_events(dlm, mle);
955 dlm_put_mle(mle);
956 /* put the extra ref */
a2bf0477 957 dlm_put_mle_inuse(mle);
6714d8e8
KH		 958
959wake_waiters:
960 spin_lock(&res->spinlock);
961 res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
962 spin_unlock(&res->spinlock);
963 wake_up(&res->wq);
964
965leave:
966 /* need to free the unused mle */
967 if (alloc_mle)
968 kmem_cache_free(dlm_mle_cache, alloc_mle);
969
970 return res;
971}
972
973
974#define DLM_MASTERY_TIMEOUT_MS 5000
975
976static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
977 struct dlm_lock_resource *res,
978 struct dlm_master_list_entry *mle,
979 int *blocked)
980{
981 u8 m;
982 int ret, bit;
983 int map_changed, voting_done;
984 int assert, sleep;
985
986recheck:
987 ret = 0;
988 assert = 0;
989
990 /* check if another node has already become the owner */
991 spin_lock(&res->spinlock);
992 if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
9c6510a5
KH		 993 mlog(0, "%s:%.*s: owner is suddenly %u\n", dlm->name,
994 res->lockname.len, res->lockname.name, res->owner);
6714d8e8 995 spin_unlock(&res->spinlock);
9c6510a5
KH		 996 /* this will cause the master to re-assert across
997 * the whole cluster, freeing up mles */
588e0090
KH		 998 if (res->owner != dlm->node_num) {
999 ret = dlm_do_master_request(mle, res->owner);
1000 if (ret < 0) {
1001 /* give recovery a chance to run */
1002 mlog(ML_ERROR, "link to %u went down?: %d\n", res->owner, ret);
1003 msleep(500);
1004 goto recheck;
1005 }
9c6510a5
KH		 1006 }
1007 ret = 0;
6714d8e8
KH		 1008 goto leave;
1009 }
1010 spin_unlock(&res->spinlock);
1011
1012 spin_lock(&mle->spinlock);
1013 m = mle->master;
1014 map_changed = (memcmp(mle->vote_map, mle->node_map,
1015 sizeof(mle->vote_map)) != 0);
1016 voting_done = (memcmp(mle->vote_map, mle->response_map,
1017 sizeof(mle->vote_map)) == 0);
1018
1019 /* restart if we hit any errors */
1020 if (map_changed) {
1021 int b;
1022 mlog(0, "%s: %.*s: node map changed, restarting\n",
1023 dlm->name, res->lockname.len, res->lockname.name);
1024 ret = dlm_restart_lock_mastery(dlm, res, mle, *blocked);
1025 b = (mle->type == DLM_MLE_BLOCK);
1026 if ((*blocked && !b) || (!*blocked && b)) {
1027 mlog(0, "%s:%.*s: status change: old=%d new=%d\n",
1028 dlm->name, res->lockname.len, res->lockname.name,
1029 *blocked, b);
1030 *blocked = b;
1031 }
1032 spin_unlock(&mle->spinlock);
1033 if (ret < 0) {
1034 mlog_errno(ret);
1035 goto leave;
1036 }
1037 mlog(0, "%s:%.*s: restart lock mastery succeeded, "
1038 "rechecking now\n", dlm->name, res->lockname.len,
1039 res->lockname.name);
1040 goto recheck;
aa852354
KH		 1041 } else {
1042 if (!voting_done) {
1043 mlog(0, "map not changed and voting not done "
1044 "for %s:%.*s\n", dlm->name, res->lockname.len,
1045 res->lockname.name);
1046 }
6714d8e8
KH		 1047 }
1048
1049 if (m != O2NM_MAX_NODES) {
1050 /* another node has done an assert!
1051 * all done! */
1052 sleep = 0;
1053 } else {
1054 sleep = 1;
1055 /* have all nodes responded? */
1056 if (voting_done && !*blocked) {
1057 bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
1058 if (dlm->node_num <= bit) {
1059 /* my node number is lowest.
1060 * now tell other nodes that I am
1061 * mastering this. */
1062 mle->master = dlm->node_num;
1063 assert = 1;
1064 sleep = 0;
1065 }
1066 /* if voting is done, but we have not received
1067 * an assert master yet, we must sleep */
1068 }
1069 }
1070
1071 spin_unlock(&mle->spinlock);
1072
1073 /* sleep if we haven't finished voting yet */
1074 if (sleep) {
1075 unsigned long timeo = msecs_to_jiffies(DLM_MASTERY_TIMEOUT_MS);
1076
1077 /*
1078 if (atomic_read(&mle->mle_refs.refcount) < 2)
1079 mlog(ML_ERROR, "mle (%p) refs=%d, name=%.*s\n", mle,
1080 atomic_read(&mle->mle_refs.refcount),
1081 res->lockname.len, res->lockname.name);
1082 */
1083 atomic_set(&mle->woken, 0);
1084 (void)wait_event_timeout(mle->wq,
1085 (atomic_read(&mle->woken) == 1),
1086 timeo);
1087 if (res->owner == O2NM_MAX_NODES) {
1088 mlog(0, "waiting again\n");
1089 goto recheck;
1090 }
1091 mlog(0, "done waiting, master is %u\n", res->owner);
1092 ret = 0;
1093 goto leave;
1094 }
1095
1096 ret = 0; /* done */
1097 if (assert) {
1098 m = dlm->node_num;
1099 mlog(0, "about to master %.*s here, this=%u\n",
1100 res->lockname.len, res->lockname.name, m);
1101 ret = dlm_do_assert_master(dlm, res->lockname.name,
1102 res->lockname.len, mle->vote_map, 0);
1103 if (ret) {
1104 /* This is a failure in the network path,
1105 * not in the response to the assert_master
1106 * (any nonzero response is a BUG on this node).
1107 * Most likely a socket just got disconnected
1108 * due to node death. */
1109 mlog_errno(ret);
1110 }
1111 /* no longer need to restart lock mastery.
1112 * all living nodes have been contacted. */
1113 ret = 0;
1114 }
1115
1116 /* set the lockres owner */
1117 spin_lock(&res->spinlock);
1118 dlm_change_lockres_owner(dlm, res, m);
1119 spin_unlock(&res->spinlock);
1120
1121leave:
1122 return ret;
1123}
1124
1125struct dlm_bitmap_diff_iter
1126{
1127 int curnode;
1128 unsigned long *orig_bm;
1129 unsigned long *cur_bm;
1130 unsigned long diff_bm[BITS_TO_LONGS(O2NM_MAX_NODES)];
1131};
1132
1133enum dlm_node_state_change
1134{
1135 NODE_DOWN = -1,
1136 NODE_NO_CHANGE = 0,
1137 NODE_UP
1138};
1139
1140static void dlm_bitmap_diff_iter_init(struct dlm_bitmap_diff_iter *iter,
1141 unsigned long *orig_bm,
1142 unsigned long *cur_bm)
1143{
1144 unsigned long p1, p2;
1145 int i;
1146
1147 iter->curnode = -1;
1148 iter->orig_bm = orig_bm;
1149 iter->cur_bm = cur_bm;
1150
1151 for (i = 0; i < BITS_TO_LONGS(O2NM_MAX_NODES); i++) {
1152 p1 = *(iter->orig_bm + i);
1153 p2 = *(iter->cur_bm + i);
1154 iter->diff_bm[i] = (p1 & ~p2) | (p2 & ~p1);
1155 }
1156}
1157
1158static int dlm_bitmap_diff_iter_next(struct dlm_bitmap_diff_iter *iter,
1159 enum dlm_node_state_change *state)
1160{
1161 int bit;
1162
1163 if (iter->curnode >= O2NM_MAX_NODES)
1164 return -ENOENT;
1165
1166 bit = find_next_bit(iter->diff_bm, O2NM_MAX_NODES,
1167 iter->curnode+1);
1168 if (bit >= O2NM_MAX_NODES) {
1169 iter->curnode = O2NM_MAX_NODES;
1170 return -ENOENT;
1171 }
1172
1173 /* if it was there in the original then this node died */
1174 if (test_bit(bit, iter->orig_bm))
1175 *state = NODE_DOWN;
1176 else
1177 *state = NODE_UP;
1178
1179 iter->curnode = bit;
1180 return bit;
1181}
1182
1183
1184static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
1185 struct dlm_lock_resource *res,
1186 struct dlm_master_list_entry *mle,
1187 int blocked)
1188{
1189 struct dlm_bitmap_diff_iter bdi;
1190 enum dlm_node_state_change sc;
1191 int node;
1192 int ret = 0;
1193
1194 mlog(0, "something happened such that the "
1195 "master process may need to be restarted!\n");
1196
1197 assert_spin_locked(&mle->spinlock);
1198
1199 dlm_bitmap_diff_iter_init(&bdi, mle->vote_map, mle->node_map);
1200 node = dlm_bitmap_diff_iter_next(&bdi, &sc);
1201 while (node >= 0) {
1202 if (sc == NODE_UP) {
e2faea4c
KH		 1203 /* a node came up. clear any old vote from
1204 * the response map and set it in the vote map
1205 * then restart the mastery. */
1206 mlog(ML_NOTICE, "node %d up while restarting\n", node);
6714d8e8
KH		 1207
1208 /* redo the master request, but only for the new node */
1209 mlog(0, "sending request to new node\n");
1210 clear_bit(node, mle->response_map);
1211 set_bit(node, mle->vote_map);
1212 } else {
1213 mlog(ML_ERROR, "node down! %d\n", node);
6714d8e8
KH		 1214 if (blocked) {
1215 int lowest = find_next_bit(mle->maybe_map,
1216 O2NM_MAX_NODES, 0);
1217
1218 /* act like it was never there */
1219 clear_bit(node, mle->maybe_map);
1220
e7e69eb3
KH		 1221 if (node == lowest) {
1222 mlog(0, "expected master %u died"
1223 " while this node was blocked "
1224 "waiting on it!\n", node);
1225 lowest = find_next_bit(mle->maybe_map,
1226 O2NM_MAX_NODES,
1227 lowest+1);
1228 if (lowest < O2NM_MAX_NODES) {
1229 mlog(0, "%s:%.*s:still "
1230 "blocked. waiting on %u "
1231 "now\n", dlm->name,
1232 res->lockname.len,
1233 res->lockname.name,
1234 lowest);
1235 } else {
1236 /* mle is an MLE_BLOCK, but
1237 * there is now nothing left to
1238 * block on. we need to return
1239 * all the way back out and try
1240 * again with an MLE_MASTER.
1241 * dlm_do_local_recovery_cleanup
1242 * has already run, so the mle
1243 * refcount is ok */
1244 mlog(0, "%s:%.*s: no "
1245 "longer blocking. try to "
1246 "master this here\n",
1247 dlm->name,
1248 res->lockname.len,
1249 res->lockname.name);
1250 mle->type = DLM_MLE_MASTER;
1251 mle->u.res = res;
1252 }
6714d8e8 1253 }
6714d8e8
KH		 1254 }
1255
e7e69eb3
KH		 1256 /* now blank out everything, as if we had never
1257 * contacted anyone */
1258 memset(mle->maybe_map, 0, sizeof(mle->maybe_map));
1259 memset(mle->response_map, 0, sizeof(mle->response_map));
1260 /* reset the vote_map to the current node_map */
1261 memcpy(mle->vote_map, mle->node_map,
1262 sizeof(mle->node_map));
1263 /* put myself into the maybe map */
1264 if (mle->type != DLM_MLE_BLOCK)
1265 set_bit(dlm->node_num, mle->maybe_map);
6714d8e8
KH		 1266 }
1267 ret = -EAGAIN;
6714d8e8
KH		 1268 node = dlm_bitmap_diff_iter_next(&bdi, &sc);
1269 }
1270 return ret;
1271}
1272
1273
1274/*
1275 * DLM_MASTER_REQUEST_MSG
1276 *
1277 * returns: 0 on success,
1278 * -errno on a network error
1279 *
1280 * on error, the caller should assume the target node is "dead"
1281 *
1282 */
1283
1284static int dlm_do_master_request(struct dlm_master_list_entry *mle, int to)
1285{
1286 struct dlm_ctxt *dlm = mle->dlm;
1287 struct dlm_master_request request;
1288 int ret, response=0, resend;
1289
1290 memset(&request, 0, sizeof(request));
1291 request.node_idx = dlm->node_num;
1292
1293 BUG_ON(mle->type == DLM_MLE_MIGRATION);
1294
1295 if (mle->type != DLM_MLE_MASTER) {
1296 request.namelen = mle->u.name.len;
1297 memcpy(request.name, mle->u.name.name, request.namelen);
1298 } else {
1299 request.namelen = mle->u.res->lockname.len;
1300 memcpy(request.name, mle->u.res->lockname.name,
1301 request.namelen);
1302 }
1303
1304again:
1305 ret = o2net_send_message(DLM_MASTER_REQUEST_MSG, dlm->key, &request,
1306 sizeof(request), to, &response);
1307 if (ret < 0) {
1308 if (ret == -ESRCH) {
1309 /* should never happen */
1310 mlog(ML_ERROR, "TCP stack not ready!\n");
1311 BUG();
1312 } else if (ret == -EINVAL) {
1313 mlog(ML_ERROR, "bad args passed to o2net!\n");
1314 BUG();
1315 } else if (ret == -ENOMEM) {
1316 mlog(ML_ERROR, "out of memory while trying to send "
1317 "network message! retrying\n");
1318 /* this is totally crude */
1319 msleep(50);
1320 goto again;
1321 } else if (!dlm_is_host_down(ret)) {
1322 /* not a network error. bad. */
1323 mlog_errno(ret);
1324 mlog(ML_ERROR, "unhandled error!");
1325 BUG();
1326 }
1327 /* all other errors should be network errors,
1328 * and likely indicate node death */
1329 mlog(ML_ERROR, "link to %d went down!\n", to);
1330 goto out;
1331 }
1332
1333 ret = 0;
1334 resend = 0;
1335 spin_lock(&mle->spinlock);
1336 switch (response) {
1337 case DLM_MASTER_RESP_YES:
1338 set_bit(to, mle->response_map);
1339 mlog(0, "node %u is the master, response=YES\n", to);
1340 mle->master = to;
1341 break;
1342 case DLM_MASTER_RESP_NO:
1343 mlog(0, "node %u not master, response=NO\n", to);
1344 set_bit(to, mle->response_map);
1345 break;
1346 case DLM_MASTER_RESP_MAYBE:
1347 mlog(0, "node %u not master, response=MAYBE\n", to);
1348 set_bit(to, mle->response_map);
1349 set_bit(to, mle->maybe_map);
1350 break;
1351 case DLM_MASTER_RESP_ERROR:
1352 mlog(0, "node %u hit an error, resending\n", to);
1353 resend = 1;
1354 response = 0;
1355 break;
1356 default:
1357 mlog(ML_ERROR, "bad response! %u\n", response);
1358 BUG();
1359 }
1360 spin_unlock(&mle->spinlock);
1361 if (resend) {
1362 /* this is also totally crude */
1363 msleep(50);
1364 goto again;
1365 }
1366
1367out:
1368 return ret;
1369}
1370
1371/*
1372 * locks that can be taken here:
1373 * dlm->spinlock
1374 * res->spinlock
1375 * mle->spinlock
1376 * dlm->master_list
1377 *
1378 * if possible, TRIM THIS DOWN!!!
1379 */
1380int dlm_master_request_handler(struct o2net_msg *msg, u32 len, void *data)
1381{
1382 u8 response = DLM_MASTER_RESP_MAYBE;
1383 struct dlm_ctxt *dlm = data;
9c6510a5 1384 struct dlm_lock_resource *res = NULL;
6714d8e8
KH		 1385 struct dlm_master_request *request = (struct dlm_master_request *) msg->buf;
1386 struct dlm_master_list_entry *mle = NULL, *tmpmle = NULL;
1387 char *name;
a3d33291 1388 unsigned int namelen, hash;
6714d8e8
KH		 1389 int found, ret;
1390 int set_maybe;
9c6510a5 1391 int dispatch_assert = 0;
6714d8e8
KH		 1392
1393 if (!dlm_grab(dlm))
1394 return DLM_MASTER_RESP_NO;
1395
1396 if (!dlm_domain_fully_joined(dlm)) {
1397 response = DLM_MASTER_RESP_NO;
1398 goto send_response;
1399 }
1400
1401 name = request->name;
1402 namelen = request->namelen;
a3d33291 1403 hash = dlm_lockid_hash(name, namelen);
6714d8e8
KH		 1404
1405 if (namelen > DLM_LOCKID_NAME_MAX) {
1406 response = DLM_IVBUFLEN;
1407 goto send_response;
1408 }
1409
1410way_up_top:
1411 spin_lock(&dlm->spinlock);
a3d33291 1412 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
6714d8e8
KH		 1413 if (res) {
1414 spin_unlock(&dlm->spinlock);
1415
1416 /* take care of the easy cases up front */
1417 spin_lock(&res->spinlock);
1418 if (res->state & DLM_LOCK_RES_RECOVERING) {
1419 spin_unlock(&res->spinlock);
1420 mlog(0, "returning DLM_MASTER_RESP_ERROR since res is "
1421 "being recovered\n");
1422 response = DLM_MASTER_RESP_ERROR;
1423 if (mle)
1424 kmem_cache_free(dlm_mle_cache, mle);
1425 goto send_response;
1426 }
1427
1428 if (res->owner == dlm->node_num) {
6714d8e8
KH		 1429 spin_unlock(&res->spinlock);
1430 // mlog(0, "this node is the master\n");
1431 response = DLM_MASTER_RESP_YES;
1432 if (mle)
1433 kmem_cache_free(dlm_mle_cache, mle);
1434
1435 /* this node is the owner.
1436 * there is some extra work that needs to
1437 * happen now. the requesting node has
1438 * caused all nodes up to this one to
1439 * create mles. this node now needs to
1440 * go back and clean those up. */
9c6510a5 1441 dispatch_assert = 1;
6714d8e8
KH		 1442 goto send_response;
1443 } else if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1444 spin_unlock(&res->spinlock);
1445 // mlog(0, "node %u is the master\n", res->owner);
1446 response = DLM_MASTER_RESP_NO;
1447 if (mle)
1448 kmem_cache_free(dlm_mle_cache, mle);
1449 goto send_response;
1450 }
1451
1452 /* ok, there is no owner. either this node is
1453 * being blocked, or it is actively trying to
1454 * master this lock. */
1455 if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
1456 mlog(ML_ERROR, "lock with no owner should be "
1457 "in-progress!\n");
1458 BUG();
1459 }
1460
1461 // mlog(0, "lockres is in progress...\n");
1462 spin_lock(&dlm->master_lock);
1463 found = dlm_find_mle(dlm, &tmpmle, name, namelen);
1464 if (!found) {
1465 mlog(ML_ERROR, "no mle found for this lock!\n");
1466 BUG();
1467 }
1468 set_maybe = 1;
1469 spin_lock(&tmpmle->spinlock);
1470 if (tmpmle->type == DLM_MLE_BLOCK) {
1471 // mlog(0, "this node is waiting for "
1472 // "lockres to be mastered\n");
1473 response = DLM_MASTER_RESP_NO;
1474 } else if (tmpmle->type == DLM_MLE_MIGRATION) {
1475 mlog(0, "node %u is master, but trying to migrate to "
1476 "node %u.\n", tmpmle->master, tmpmle->new_master);
1477 if (tmpmle->master == dlm->node_num) {
1478 response = DLM_MASTER_RESP_YES;
1479 mlog(ML_ERROR, "no owner on lockres, but this "
1480 "node is trying to migrate it to %u?!\n",
1481 tmpmle->new_master);
1482 BUG();
1483 } else {
1484 /* the real master can respond on its own */
1485 response = DLM_MASTER_RESP_NO;
1486 }
1487 } else if (tmpmle->master != DLM_LOCK_RES_OWNER_UNKNOWN) {
1488 set_maybe = 0;
9c6510a5 1489 if (tmpmle->master == dlm->node_num) {
6714d8e8 1490 response = DLM_MASTER_RESP_YES;
9c6510a5
KH		 1491 /* this node will be the owner.
1492 * go back and clean the mles on any
1493 * other nodes */
1494 dispatch_assert = 1;
1495 } else
6714d8e8
KH		 1496 response = DLM_MASTER_RESP_NO;
1497 } else {
1498 // mlog(0, "this node is attempting to "
1499 // "master lockres\n");
1500 response = DLM_MASTER_RESP_MAYBE;
1501 }
1502 if (set_maybe)
1503 set_bit(request->node_idx, tmpmle->maybe_map);
1504 spin_unlock(&tmpmle->spinlock);
1505
1506 spin_unlock(&dlm->master_lock);
1507 spin_unlock(&res->spinlock);
1508
1509 /* keep the mle attached to heartbeat events */
1510 dlm_put_mle(tmpmle);
1511 if (mle)
1512 kmem_cache_free(dlm_mle_cache, mle);
1513 goto send_response;
1514 }
1515
1516 /*
1517 * lockres doesn't exist on this node
1518 * if there is an MLE_BLOCK, return NO
1519 * if there is an MLE_MASTER, return MAYBE
1520 * otherwise, add an MLE_BLOCK, return NO
1521 */
1522 spin_lock(&dlm->master_lock);
1523 found = dlm_find_mle(dlm, &tmpmle, name, namelen);
1524 if (!found) {
1525 /* this lockid has never been seen on this node yet */
1526 // mlog(0, "no mle found\n");
1527 if (!mle) {
1528 spin_unlock(&dlm->master_lock);
1529 spin_unlock(&dlm->spinlock);
1530
1531 mle = (struct dlm_master_list_entry *)
1532 kmem_cache_alloc(dlm_mle_cache, GFP_KERNEL);
1533 if (!mle) {
6714d8e8 1534 response = DLM_MASTER_RESP_ERROR;
9c6510a5 1535 mlog_errno(-ENOMEM);
6714d8e8
KH		 1536 goto send_response;
1537 }
6714d8e8
KH		 1538 goto way_up_top;
1539 }
1540
1541 // mlog(0, "this is second time thru, already allocated, "
1542 // "add the block.\n");
41b8c8a1 1543 dlm_init_mle(mle, DLM_MLE_BLOCK, dlm, NULL, name, namelen);
6714d8e8
KH		 1544 set_bit(request->node_idx, mle->maybe_map);
1545 list_add(&mle->list, &dlm->master_list);
1546 response = DLM_MASTER_RESP_NO;
1547 } else {
1548 // mlog(0, "mle was found\n");
1549 set_maybe = 1;
1550 spin_lock(&tmpmle->spinlock);
9c6510a5
KH		 1551 if (tmpmle->master == dlm->node_num) {
1552 mlog(ML_ERROR, "no lockres, but an mle with this node as master!\n");
1553 BUG();
1554 }
6714d8e8
KH		 1555 if (tmpmle->type == DLM_MLE_BLOCK)
1556 response = DLM_MASTER_RESP_NO;
1557 else if (tmpmle->type == DLM_MLE_MIGRATION) {
1558 mlog(0, "migration mle was found (%u->%u)\n",
1559 tmpmle->master, tmpmle->new_master);
6714d8e8
KH		 1560 /* real master can respond on its own */
1561 response = DLM_MASTER_RESP_NO;
9c6510a5
KH		 1562 } else
1563 response = DLM_MASTER_RESP_MAYBE;
6714d8e8
KH		 1564 if (set_maybe)
1565 set_bit(request->node_idx, tmpmle->maybe_map);
1566 spin_unlock(&tmpmle->spinlock);
1567 }
1568 spin_unlock(&dlm->master_lock);
1569 spin_unlock(&dlm->spinlock);
1570
1571 if (found) {
1572 /* keep the mle attached to heartbeat events */
1573 dlm_put_mle(tmpmle);
1574 }
1575send_response:
9c6510a5
KH		 1576
1577 if (dispatch_assert) {
1578 if (response != DLM_MASTER_RESP_YES)
1579 mlog(ML_ERROR, "invalid response %d\n", response);
1580 if (!res) {
1581 mlog(ML_ERROR, "bad lockres while trying to assert!\n");
1582 BUG();
1583 }
1584 mlog(0, "%u is the owner of %.*s, cleaning everyone else\n",
1585 dlm->node_num, res->lockname.len, res->lockname.name);
1586 ret = dlm_dispatch_assert_master(dlm, res, 0, request->node_idx,
1587 DLM_ASSERT_MASTER_MLE_CLEANUP);
1588 if (ret < 0) {
1589 mlog(ML_ERROR, "failed to dispatch assert master work\n");
1590 response = DLM_MASTER_RESP_ERROR;
1591 }
1592 }
1593
6714d8e8
KH		 1594 dlm_put(dlm);
1595 return response;
1596}
1597
1598/*
1599 * DLM_ASSERT_MASTER_MSG
1600 */
1601
1602
1603/*
1604 * NOTE: this can be used for debugging
1605 * can periodically run all locks owned by this node
1606 * and re-assert across the cluster...
1607 */
1608static int dlm_do_assert_master(struct dlm_ctxt *dlm, const char *lockname,
1609 unsigned int namelen, void *nodemap,
1610 u32 flags)
1611{
1612 struct dlm_assert_master assert;
1613 int to, tmpret;
1614 struct dlm_node_iter iter;
1615 int ret = 0;
9c6510a5 1616 int reassert;
6714d8e8
KH		 1617
1618 BUG_ON(namelen > O2NM_MAX_NAME_LEN);
9c6510a5
KH		 1619again:
1620 reassert = 0;
6714d8e8
KH		 1621
1622 /* note that if this nodemap is empty, it returns 0 */
1623 dlm_node_iter_init(nodemap, &iter);
1624 while ((to = dlm_node_iter_next(&iter)) >= 0) {
1625 int r = 0;
a9ee4c8a
KH		 1626 struct dlm_master_list_entry *mle = NULL;
1627
6714d8e8
KH		 1628 mlog(0, "sending assert master to %d (%.*s)\n", to,
1629 namelen, lockname);
1630 memset(&assert, 0, sizeof(assert));
1631 assert.node_idx = dlm->node_num;
1632 assert.namelen = namelen;
1633 memcpy(assert.name, lockname, namelen);
1634 assert.flags = cpu_to_be32(flags);
1635
1636 tmpret = o2net_send_message(DLM_ASSERT_MASTER_MSG, dlm->key,
1637 &assert, sizeof(assert), to, &r);
1638 if (tmpret < 0) {
1639 mlog(ML_ERROR, "assert_master returned %d!\n", tmpret);
1640 if (!dlm_is_host_down(tmpret)) {
1641 mlog(ML_ERROR, "unhandled error!\n");
1642 BUG();
1643 }
1644 /* a node died. finish out the rest of the nodes. */
1645 mlog(ML_ERROR, "link to %d went down!\n", to);
1646 /* any nonzero status return will do */
1647 ret = tmpret;
1648 } else if (r < 0) {
1649 /* ok, something horribly messed. kill thyself. */
1650 mlog(ML_ERROR,"during assert master of %.*s to %u, "
1651 "got %d.\n", namelen, lockname, to, r);
a9ee4c8a
KH		 1652 spin_lock(&dlm->spinlock);
1653 spin_lock(&dlm->master_lock);
1654 if (dlm_find_mle(dlm, &mle, (char *)lockname,
1655 namelen)) {
1656 dlm_print_one_mle(mle);
1657 __dlm_put_mle(mle);
1658 }
1659 spin_unlock(&dlm->master_lock);
1660 spin_unlock(&dlm->spinlock);
6714d8e8 1661 BUG();
9c6510a5
KH		 1662 } else if (r == EAGAIN) {
1663 mlog(0, "%.*s: node %u create mles on other "
1664 "nodes and requests a re-assert\n",
1665 namelen, lockname, to);
1666 reassert = 1;
6714d8e8
KH		 1667 }
1668 }
1669
9c6510a5
KH		 1670 if (reassert)
1671 goto again;
1672
6714d8e8
KH		 1673 return ret;
1674}
1675
1676/*
1677 * locks that can be taken here:
1678 * dlm->spinlock
1679 * res->spinlock
1680 * mle->spinlock
1681 * dlm->master_list
1682 *
1683 * if possible, TRIM THIS DOWN!!!
1684 */
1685int dlm_assert_master_handler(struct o2net_msg *msg, u32 len, void *data)
1686{
1687 struct dlm_ctxt *dlm = data;
1688 struct dlm_master_list_entry *mle = NULL;
1689 struct dlm_assert_master *assert = (struct dlm_assert_master *)msg->buf;
1690 struct dlm_lock_resource *res = NULL;
1691 char *name;
a3d33291 1692 unsigned int namelen, hash;
6714d8e8 1693 u32 flags;
9c6510a5
KH		 1694 int master_request = 0;
1695 int ret = 0;
6714d8e8
KH		 1696
1697 if (!dlm_grab(dlm))
1698 return 0;
1699
1700 name = assert->name;
1701 namelen = assert->namelen;
a3d33291 1702 hash = dlm_lockid_hash(name, namelen);
6714d8e8
KH		 1703 flags = be32_to_cpu(assert->flags);
1704
1705 if (namelen > DLM_LOCKID_NAME_MAX) {
1706 mlog(ML_ERROR, "Invalid name length!");
1707 goto done;
1708 }
1709
1710 spin_lock(&dlm->spinlock);
1711
1712 if (flags)
1713 mlog(0, "assert_master with flags: %u\n", flags);
1714
1715 /* find the MLE */
1716 spin_lock(&dlm->master_lock);
1717 if (!dlm_find_mle(dlm, &mle, name, namelen)) {
1718 /* not an error, could be master just re-asserting */
1719 mlog(0, "just got an assert_master from %u, but no "
1720 "MLE for it! (%.*s)\n", assert->node_idx,
1721 namelen, name);
1722 } else {
1723 int bit = find_next_bit (mle->maybe_map, O2NM_MAX_NODES, 0);
1724 if (bit >= O2NM_MAX_NODES) {
1725 /* not necessarily an error, though less likely.
1726 * could be master just re-asserting. */
aa852354 1727 mlog(0, "no bits set in the maybe_map, but %u "
6714d8e8
KH		 1728 "is asserting! (%.*s)\n", assert->node_idx,
1729 namelen, name);
1730 } else if (bit != assert->node_idx) {
1731 if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
1732 mlog(0, "master %u was found, %u should "
1733 "back off\n", assert->node_idx, bit);
1734 } else {
1735 /* with the fix for bug 569, a higher node
1736 * number winning the mastery will respond
1737 * YES to mastery requests, but this node
1738 * had no way of knowing. let it pass. */
aa852354 1739 mlog(0, "%u is the lowest node, "
6714d8e8
KH		 1740 "%u is asserting. (%.*s) %u must "
1741 "have begun after %u won.\n", bit,
1742 assert->node_idx, namelen, name, bit,
1743 assert->node_idx);
1744 }
1745 }
2d1a868c
KH		 1746 if (mle->type == DLM_MLE_MIGRATION) {
1747 if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
1748 mlog(0, "%s:%.*s: got cleanup assert"
1749 " from %u for migration\n",
1750 dlm->name, namelen, name,
1751 assert->node_idx);
1752 } else if (!(flags & DLM_ASSERT_MASTER_FINISH_MIGRATION)) {
1753 mlog(0, "%s:%.*s: got unrelated assert"
1754 " from %u for migration, ignoring\n",
1755 dlm->name, namelen, name,
1756 assert->node_idx);
1757 __dlm_put_mle(mle);
1758 spin_unlock(&dlm->master_lock);
1759 spin_unlock(&dlm->spinlock);
1760 goto done;
1761 }
1762 }
6714d8e8
KH		 1763 }
1764 spin_unlock(&dlm->master_lock);
1765
1766 /* ok everything checks out with the MLE
1767 * now check to see if there is a lockres */
a3d33291 1768 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
6714d8e8
KH		 1769 if (res) {
1770 spin_lock(&res->spinlock);
1771 if (res->state & DLM_LOCK_RES_RECOVERING) {
1772 mlog(ML_ERROR, "%u asserting but %.*s is "
1773 "RECOVERING!\n", assert->node_idx, namelen, name);
1774 goto kill;
1775 }
1776 if (!mle) {
dc2ed195
KH		 1777 if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN &&
1778 res->owner != assert->node_idx) {
6714d8e8
KH		 1779 mlog(ML_ERROR, "assert_master from "
1780 "%u, but current owner is "
1781 "%u! (%.*s)\n",
1782 assert->node_idx, res->owner,
1783 namelen, name);
1784 goto kill;
1785 }
1786 } else if (mle->type != DLM_MLE_MIGRATION) {
1787 if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1788 /* owner is just re-asserting */
1789 if (res->owner == assert->node_idx) {
1790 mlog(0, "owner %u re-asserting on "
1791 "lock %.*s\n", assert->node_idx,
1792 namelen, name);
1793 goto ok;
1794 }
1795 mlog(ML_ERROR, "got assert_master from "
1796 "node %u, but %u is the owner! "
1797 "(%.*s)\n", assert->node_idx,
1798 res->owner, namelen, name);
1799 goto kill;
1800 }
1801 if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
1802 mlog(ML_ERROR, "got assert from %u, but lock "
1803 "with no owner should be "
1804 "in-progress! (%.*s)\n",
1805 assert->node_idx,
1806 namelen, name);
1807 goto kill;
1808 }
1809 } else /* mle->type == DLM_MLE_MIGRATION */ {
1810 /* should only be getting an assert from new master */
1811 if (assert->node_idx != mle->new_master) {
1812 mlog(ML_ERROR, "got assert from %u, but "
1813 "new master is %u, and old master "
1814 "was %u (%.*s)\n",
1815 assert->node_idx, mle->new_master,
1816 mle->master, namelen, name);
1817 goto kill;
1818 }
1819
1820 }
1821ok:
1822 spin_unlock(&res->spinlock);
1823 }
1824 spin_unlock(&dlm->spinlock);
1825
1826 // mlog(0, "woo! got an assert_master from node %u!\n",
1827 // assert->node_idx);
1828 if (mle) {
9c6510a5
KH		 1829 int extra_ref = 0;
1830 int nn = -1;
a2bf0477 1831 int rr, err = 0;
6714d8e8
KH		 1832
1833 spin_lock(&mle->spinlock);
9c6510a5
KH		 1834 if (mle->type == DLM_MLE_BLOCK || mle->type == DLM_MLE_MIGRATION)
1835 extra_ref = 1;
1836 else {
1837 /* MASTER mle: if any bits set in the response map
1838 * then the calling node needs to re-assert to clear
1839 * up nodes that this node contacted */
1840 while ((nn = find_next_bit (mle->response_map, O2NM_MAX_NODES,
1841 nn+1)) < O2NM_MAX_NODES) {
1842 if (nn != dlm->node_num && nn != assert->node_idx)
1843 master_request = 1;
1844 }
1845 }
6714d8e8
KH		 1846 mle->master = assert->node_idx;
1847 atomic_set(&mle->woken, 1);
1848 wake_up(&mle->wq);
1849 spin_unlock(&mle->spinlock);
1850
a2bf0477 1851 if (res) {
6714d8e8 1852 spin_lock(&res->spinlock);
a2bf0477
KH		 1853 if (mle->type == DLM_MLE_MIGRATION) {
1854 mlog(0, "finishing off migration of lockres %.*s, "
1855 "from %u to %u\n",
1856 res->lockname.len, res->lockname.name,
1857 dlm->node_num, mle->new_master);
1858 res->state &= ~DLM_LOCK_RES_MIGRATING;
1859 dlm_change_lockres_owner(dlm, res, mle->new_master);
1860 BUG_ON(res->state & DLM_LOCK_RES_DIRTY);
1861 } else {
1862 dlm_change_lockres_owner(dlm, res, mle->master);
1863 }
6714d8e8
KH		 1864 spin_unlock(&res->spinlock);
1865 }
a2bf0477
KH		 1866
1867 /* master is known, detach if not already detached.
1868 * ensures that only one assert_master call will happen
1869 * on this mle. */
1870 spin_lock(&dlm->spinlock);
1871 spin_lock(&dlm->master_lock);
1872
1873 rr = atomic_read(&mle->mle_refs.refcount);
1874 if (mle->inuse > 0) {
1875 if (extra_ref && rr < 3)
1876 err = 1;
1877 else if (!extra_ref && rr < 2)
1878 err = 1;
1879 } else {
1880 if (extra_ref && rr < 2)
1881 err = 1;
1882 else if (!extra_ref && rr < 1)
1883 err = 1;
1884 }
1885 if (err) {
1886 mlog(ML_ERROR, "%s:%.*s: got assert master from %u "
1887 "that will mess up this node, refs=%d, extra=%d, "
1888 "inuse=%d\n", dlm->name, namelen, name,
1889 assert->node_idx, rr, extra_ref, mle->inuse);
1890 dlm_print_one_mle(mle);
1891 }
1892 list_del_init(&mle->list);
1893 __dlm_mle_detach_hb_events(dlm, mle);
1894 __dlm_put_mle(mle);
6714d8e8
KH		 1895 if (extra_ref) {
1896 /* the assert master message now balances the extra
1897 * ref given by the master / migration request message.
1898 * if this is the last put, it will be removed
1899 * from the list. */
a2bf0477
KH		 1900 __dlm_put_mle(mle);
1901 }
1902 spin_unlock(&dlm->master_lock);
1903 spin_unlock(&dlm->spinlock);
1904 } else if (res) {
1905 if (res->owner != assert->node_idx) {
1906 mlog(0, "assert_master from %u, but current "
1907 "owner is %u (%.*s), no mle\n", assert->node_idx,
1908 res->owner, namelen, name);
6714d8e8
KH		 1909 }
1910 }
1911
1912done:
9c6510a5 1913 ret = 0;
6714d8e8
KH		 1914 if (res)
1915 dlm_lockres_put(res);
1916 dlm_put(dlm);
9c6510a5
KH		 1917 if (master_request) {
1918 mlog(0, "need to tell master to reassert\n");
1919 ret = EAGAIN; // positive. negative would shoot down the node.
1920 }
1921 return ret;
6714d8e8
KH		 1922
1923kill:
1924 /* kill the caller! */
a9ee4c8a
KH		 1925 mlog(ML_ERROR, "Bad message received from another node. Dumping state "
1926 "and killing the other node now! This node is OK and can continue.\n");
1927 __dlm_print_one_lock_resource(res);
6714d8e8
KH		 1928 spin_unlock(&res->spinlock);
1929 spin_unlock(&dlm->spinlock);
1930 dlm_lockres_put(res);
6714d8e8
KH		 1931 dlm_put(dlm);
1932 return -EINVAL;
1933}
1934
1935int dlm_dispatch_assert_master(struct dlm_ctxt *dlm,
1936 struct dlm_lock_resource *res,
1937 int ignore_higher, u8 request_from, u32 flags)
1938{
1939 struct dlm_work_item *item;
1940 item = kcalloc(1, sizeof(*item), GFP_KERNEL);
1941 if (!item)
1942 return -ENOMEM;
1943
1944
1945 /* queue up work for dlm_assert_master_worker */
1946 dlm_grab(dlm); /* get an extra ref for the work item */
1947 dlm_init_work_item(dlm, item, dlm_assert_master_worker, NULL);
1948 item->u.am.lockres = res; /* already have a ref */
1949 /* can optionally ignore node numbers higher than this node */
1950 item->u.am.ignore_higher = ignore_higher;
1951 item->u.am.request_from = request_from;
1952 item->u.am.flags = flags;
1953
9c6510a5
KH		 1954 if (ignore_higher)
1955 mlog(0, "IGNORE HIGHER: %.*s\n", res->lockname.len,
1956 res->lockname.name);
1957
6714d8e8
KH		 1958 spin_lock(&dlm->work_lock);
1959 list_add_tail(&item->list, &dlm->work_list);
1960 spin_unlock(&dlm->work_lock);
1961
1962 schedule_work(&dlm->dispatched_work);
1963 return 0;
1964}
1965
1966static void dlm_assert_master_worker(struct dlm_work_item *item, void *data)
1967{
1968 struct dlm_ctxt *dlm = data;
1969 int ret = 0;
1970 struct dlm_lock_resource *res;
1971 unsigned long nodemap[BITS_TO_LONGS(O2NM_MAX_NODES)];
1972 int ignore_higher;
1973 int bit;
1974 u8 request_from;
1975 u32 flags;
1976
1977 dlm = item->dlm;
1978 res = item->u.am.lockres;
1979 ignore_higher = item->u.am.ignore_higher;
1980 request_from = item->u.am.request_from;
1981 flags = item->u.am.flags;
1982
1983 spin_lock(&dlm->spinlock);
1984 memcpy(nodemap, dlm->domain_map, sizeof(nodemap));
1985 spin_unlock(&dlm->spinlock);
1986
1987 clear_bit(dlm->node_num, nodemap);
1988 if (ignore_higher) {
1989 /* if is this just to clear up mles for nodes below
1990 * this node, do not send the message to the original
1991 * caller or any node number higher than this */
1992 clear_bit(request_from, nodemap);
1993 bit = dlm->node_num;
1994 while (1) {
1995 bit = find_next_bit(nodemap, O2NM_MAX_NODES,
1996 bit+1);
1997 if (bit >= O2NM_MAX_NODES)
1998 break;
1999 clear_bit(bit, nodemap);
2000 }
2001 }
2002
36407488
KH		 2003 /*
2004 * If we're migrating this lock to someone else, we are no
2005 * longer allowed to assert out own mastery. OTOH, we need to
2006 * prevent migration from starting while we're still asserting
2007 * our dominance. The reserved ast delays migration.
2008 */
2009 spin_lock(&res->spinlock);
2010 if (res->state & DLM_LOCK_RES_MIGRATING) {
2011 mlog(0, "Someone asked us to assert mastery, but we're "
2012 "in the middle of migration. Skipping assert, "
2013 "the new master will handle that.\n");
2014 spin_unlock(&res->spinlock);
2015 goto put;
2016 } else
2017 __dlm_lockres_reserve_ast(res);
2018 spin_unlock(&res->spinlock);
2019
6714d8e8
KH		 2020 /* this call now finishes out the nodemap
2021 * even if one or more nodes die */
2022 mlog(0, "worker about to master %.*s here, this=%u\n",
2023 res->lockname.len, res->lockname.name, dlm->node_num);
2024 ret = dlm_do_assert_master(dlm, res->lockname.name,
2025 res->lockname.len,
2026 nodemap, flags);
2027 if (ret < 0) {
2028 /* no need to restart, we are done */
2029 mlog_errno(ret);
2030 }
2031
36407488
KH		 2032 /* Ok, we've asserted ourselves. Let's let migration start. */
2033 dlm_lockres_release_ast(dlm, res);
2034
2035put:
6714d8e8
KH		 2036 dlm_lockres_put(res);
2037
2038 mlog(0, "finished with dlm_assert_master_worker\n");
2039}
2040
c03872f5
KH		 2041/* SPECIAL CASE for the $RECOVERY lock used by the recovery thread.
2042 * We cannot wait for node recovery to complete to begin mastering this
2043 * lockres because this lockres is used to kick off recovery! ;-)
2044 * So, do a pre-check on all living nodes to see if any of those nodes
2045 * think that $RECOVERY is currently mastered by a dead node. If so,
2046 * we wait a short time to allow that node to get notified by its own
2047 * heartbeat stack, then check again. All $RECOVERY lock resources
2048 * mastered by dead nodes are purged when the hearbeat callback is
2049 * fired, so we can know for sure that it is safe to continue once
2050 * the node returns a live node or no node. */
2051static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
2052 struct dlm_lock_resource *res)
2053{
2054 struct dlm_node_iter iter;
2055 int nodenum;
2056 int ret = 0;
2057 u8 master = DLM_LOCK_RES_OWNER_UNKNOWN;
2058
2059 spin_lock(&dlm->spinlock);
2060 dlm_node_iter_init(dlm->domain_map, &iter);
2061 spin_unlock(&dlm->spinlock);
2062
2063 while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
2064 /* do not send to self */
2065 if (nodenum == dlm->node_num)
2066 continue;
2067 ret = dlm_do_master_requery(dlm, res, nodenum, &master);
2068 if (ret < 0) {
2069 mlog_errno(ret);
2070 if (!dlm_is_host_down(ret))
2071 BUG();
2072 /* host is down, so answer for that node would be
2073 * DLM_LOCK_RES_OWNER_UNKNOWN. continue. */
f42a100b 2074 ret = 0;
c03872f5
KH		 2075 }
2076
2077 if (master != DLM_LOCK_RES_OWNER_UNKNOWN) {
2078 /* check to see if this master is in the recovery map */
2079 spin_lock(&dlm->spinlock);
2080 if (test_bit(master, dlm->recovery_map)) {
2081 mlog(ML_NOTICE, "%s: node %u has not seen "
2082 "node %u go down yet, and thinks the "
2083 "dead node is mastering the recovery "
2084 "lock. must wait.\n", dlm->name,
2085 nodenum, master);
2086 ret = -EAGAIN;
2087 }
2088 spin_unlock(&dlm->spinlock);
2089 mlog(0, "%s: reco lock master is %u\n", dlm->name,
2090 master);
2091 break;
2092 }
2093 }
2094 return ret;
2095}
2096
6714d8e8
KH		 2097
2098/*
2099 * DLM_MIGRATE_LOCKRES
2100 */
2101
2102
2103int dlm_migrate_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
2104 u8 target)
2105{
2106 struct dlm_master_list_entry *mle = NULL;
2107 struct dlm_master_list_entry *oldmle = NULL;
2108 struct dlm_migratable_lockres *mres = NULL;
2109 int ret = -EINVAL;
2110 const char *name;
2111 unsigned int namelen;
2112 int mle_added = 0;
2113 struct list_head *queue, *iter;
2114 int i;
2115 struct dlm_lock *lock;
2116 int empty = 1;
2117
2118 if (!dlm_grab(dlm))
2119 return -EINVAL;
2120
2121 name = res->lockname.name;
2122 namelen = res->lockname.len;
2123
2124 mlog(0, "migrating %.*s to %u\n", namelen, name, target);
2125
2126 /*
2127 * ensure this lockres is a proper candidate for migration
2128 */
2129 spin_lock(&res->spinlock);
2130 if (res->owner == DLM_LOCK_RES_OWNER_UNKNOWN) {
2131 mlog(0, "cannot migrate lockres with unknown owner!\n");
2132 spin_unlock(&res->spinlock);
2133 goto leave;
2134 }
2135 if (res->owner != dlm->node_num) {
2136 mlog(0, "cannot migrate lockres this node doesn't own!\n");
2137 spin_unlock(&res->spinlock);
2138 goto leave;
2139 }
2140 mlog(0, "checking queues...\n");
2141 queue = &res->granted;
2142 for (i=0; i<3; i++) {
2143 list_for_each(iter, queue) {
2144 lock = list_entry (iter, struct dlm_lock, list);
2145 empty = 0;
2146 if (lock->ml.node == dlm->node_num) {
2147 mlog(0, "found a lock owned by this node "
2148 "still on the %s queue! will not "
2149 "migrate this lockres\n",
2150 i==0 ? "granted" :
2151 (i==1 ? "converting" : "blocked"));
2152 spin_unlock(&res->spinlock);
2153 ret = -ENOTEMPTY;
2154 goto leave;
2155 }
2156 }
2157 queue++;
2158 }
2159 mlog(0, "all locks on this lockres are nonlocal. continuing\n");
2160 spin_unlock(&res->spinlock);
2161
2162 /* no work to do */
2163 if (empty) {
2164 mlog(0, "no locks were found on this lockres! done!\n");
2165 ret = 0;
2166 goto leave;
2167 }
2168
2169 /*
2170 * preallocate up front
2171 * if this fails, abort
2172 */
2173
2174 ret = -ENOMEM;
2175 mres = (struct dlm_migratable_lockres *) __get_free_page(GFP_KERNEL);
2176 if (!mres) {
2177 mlog_errno(ret);
2178 goto leave;
2179 }
2180
2181 mle = (struct dlm_master_list_entry *) kmem_cache_alloc(dlm_mle_cache,
2182 GFP_KERNEL);
2183 if (!mle) {
2184 mlog_errno(ret);
2185 goto leave;
2186 }
2187 ret = 0;
2188
2189 /*
2190 * find a node to migrate the lockres to
2191 */
2192
2193 mlog(0, "picking a migration node\n");
2194 spin_lock(&dlm->spinlock);
2195 /* pick a new node */
2196 if (!test_bit(target, dlm->domain_map) ||
2197 target >= O2NM_MAX_NODES) {
2198 target = dlm_pick_migration_target(dlm, res);
2199 }
2200 mlog(0, "node %u chosen for migration\n", target);
2201
2202 if (target >= O2NM_MAX_NODES ||
2203 !test_bit(target, dlm->domain_map)) {
2204 /* target chosen is not alive */
2205 ret = -EINVAL;
2206 }
2207
2208 if (ret) {
2209 spin_unlock(&dlm->spinlock);
2210 goto fail;
2211 }
2212
2213 mlog(0, "continuing with target = %u\n", target);
2214
2215 /*
2216 * clear any existing master requests and
2217 * add the migration mle to the list
2218 */
2219 spin_lock(&dlm->master_lock);
2220 ret = dlm_add_migration_mle(dlm, res, mle, &oldmle, name,
2221 namelen, target, dlm->node_num);
2222 spin_unlock(&dlm->master_lock);
2223 spin_unlock(&dlm->spinlock);
2224
2225 if (ret == -EEXIST) {
2226 mlog(0, "another process is already migrating it\n");
2227 goto fail;
2228 }
2229 mle_added = 1;
2230
2231 /*
2232 * set the MIGRATING flag and flush asts
2233 * if we fail after this we need to re-dirty the lockres
2234 */
2235 if (dlm_mark_lockres_migrating(dlm, res, target) < 0) {
2236 mlog(ML_ERROR, "tried to migrate %.*s to %u, but "
2237 "the target went down.\n", res->lockname.len,
2238 res->lockname.name, target);
2239 spin_lock(&res->spinlock);
2240 res->state &= ~DLM_LOCK_RES_MIGRATING;
2241 spin_unlock(&res->spinlock);
2242 ret = -EINVAL;
2243 }
2244
2245fail:
2246 if (oldmle) {
2247 /* master is known, detach if not already detached */
2248 dlm_mle_detach_hb_events(dlm, oldmle);
2249 dlm_put_mle(oldmle);
2250 }
2251
2252 if (ret < 0) {
2253 if (mle_added) {
2254 dlm_mle_detach_hb_events(dlm, mle);
2255 dlm_put_mle(mle);
2256 } else if (mle) {
2257 kmem_cache_free(dlm_mle_cache, mle);
2258 }
2259 goto leave;
2260 }
2261
2262 /*
2263 * at this point, we have a migration target, an mle
2264 * in the master list, and the MIGRATING flag set on
2265 * the lockres
2266 */
2267
2268
2269 /* get an extra reference on the mle.
2270 * otherwise the assert_master from the new
2271 * master will destroy this.
2272 * also, make sure that all callers of dlm_get_mle
2273 * take both dlm->spinlock and dlm->master_lock */
2274 spin_lock(&dlm->spinlock);
2275 spin_lock(&dlm->master_lock);
a2bf0477 2276 dlm_get_mle_inuse(mle);
6714d8e8
KH		 2277 spin_unlock(&dlm->master_lock);
2278 spin_unlock(&dlm->spinlock);
2279
2280 /* notify new node and send all lock state */
2281 /* call send_one_lockres with migration flag.
2282 * this serves as notice to the target node that a
2283 * migration is starting. */
2284 ret = dlm_send_one_lockres(dlm, res, mres, target,
2285 DLM_MRES_MIGRATION);
2286
2287 if (ret < 0) {
2288 mlog(0, "migration to node %u failed with %d\n",
2289 target, ret);
2290 /* migration failed, detach and clean up mle */
2291 dlm_mle_detach_hb_events(dlm, mle);
2292 dlm_put_mle(mle);
a2bf0477
KH		 2293 dlm_put_mle_inuse(mle);
2294 spin_lock(&res->spinlock);
2295 res->state &= ~DLM_LOCK_RES_MIGRATING;
2296 spin_unlock(&res->spinlock);
6714d8e8
KH		 2297 goto leave;
2298 }
2299
2300 /* at this point, the target sends a message to all nodes,
2301 * (using dlm_do_migrate_request). this node is skipped since
2302 * we had to put an mle in the list to begin the process. this
2303 * node now waits for target to do an assert master. this node
2304 * will be the last one notified, ensuring that the migration
2305 * is complete everywhere. if the target dies while this is
2306 * going on, some nodes could potentially see the target as the
2307 * master, so it is important that my recovery finds the migration
2308 * mle and sets the master to UNKNONWN. */
2309
2310
2311 /* wait for new node to assert master */
2312 while (1) {
2313 ret = wait_event_interruptible_timeout(mle->wq,
2314 (atomic_read(&mle->woken) == 1),
2315 msecs_to_jiffies(5000));
2316
2317 if (ret >= 0) {
2318 if (atomic_read(&mle->woken) == 1 ||
2319 res->owner == target)
2320 break;
2321
2322 mlog(0, "timed out during migration\n");
e2faea4c
KH		 2323 /* avoid hang during shutdown when migrating lockres
2324 * to a node which also goes down */
2325 if (dlm_is_node_dead(dlm, target)) {
aa852354
KH		 2326 mlog(0, "%s:%.*s: expected migration "
2327 "target %u is no longer up, restarting\n",
e2faea4c
KH		 2328 dlm->name, res->lockname.len,
2329 res->lockname.name, target);
2330 ret = -ERESTARTSYS;
2331 }
6714d8e8
KH		 2332 }
2333 if (ret == -ERESTARTSYS) {
2334 /* migration failed, detach and clean up mle */
2335 dlm_mle_detach_hb_events(dlm, mle);
2336 dlm_put_mle(mle);
a2bf0477
KH		 2337 dlm_put_mle_inuse(mle);
2338 spin_lock(&res->spinlock);
2339 res->state &= ~DLM_LOCK_RES_MIGRATING;
2340 spin_unlock(&res->spinlock);
6714d8e8
KH		 2341 goto leave;
2342 }
2343 /* TODO: if node died: stop, clean up, return error */
2344 }
2345
2346 /* all done, set the owner, clear the flag */
2347 spin_lock(&res->spinlock);
2348 dlm_set_lockres_owner(dlm, res, target);
2349 res->state &= ~DLM_LOCK_RES_MIGRATING;
2350 dlm_remove_nonlocal_locks(dlm, res);
2351 spin_unlock(&res->spinlock);
2352 wake_up(&res->wq);
2353
2354 /* master is known, detach if not already detached */
2355 dlm_mle_detach_hb_events(dlm, mle);
a2bf0477 2356 dlm_put_mle_inuse(mle);
6714d8e8
KH		 2357 ret = 0;
2358
2359 dlm_lockres_calc_usage(dlm, res);
2360
2361leave:
2362 /* re-dirty the lockres if we failed */
2363 if (ret < 0)
2364 dlm_kick_thread(dlm, res);
2365
2366 /* TODO: cleanup */
2367 if (mres)
2368 free_page((unsigned long)mres);
2369
2370 dlm_put(dlm);
2371
2372 mlog(0, "returning %d\n", ret);
2373 return ret;
2374}
2375EXPORT_SYMBOL_GPL(dlm_migrate_lockres);
2376
2377int dlm_lock_basts_flushed(struct dlm_ctxt *dlm, struct dlm_lock *lock)
2378{
2379 int ret;
2380 spin_lock(&dlm->ast_lock);
2381 spin_lock(&lock->spinlock);
2382 ret = (list_empty(&lock->bast_list) && !lock->bast_pending);
2383 spin_unlock(&lock->spinlock);
2384 spin_unlock(&dlm->ast_lock);
2385 return ret;
2386}
2387
2388static int dlm_migration_can_proceed(struct dlm_ctxt *dlm,
2389 struct dlm_lock_resource *res,
2390 u8 mig_target)
2391{
2392 int can_proceed;
2393 spin_lock(&res->spinlock);
2394 can_proceed = !!(res->state & DLM_LOCK_RES_MIGRATING);
2395 spin_unlock(&res->spinlock);
2396
2397 /* target has died, so make the caller break out of the
2398 * wait_event, but caller must recheck the domain_map */
2399 spin_lock(&dlm->spinlock);
2400 if (!test_bit(mig_target, dlm->domain_map))
2401 can_proceed = 1;
2402 spin_unlock(&dlm->spinlock);
2403 return can_proceed;
2404}
2405
2406int dlm_lockres_is_dirty(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
2407{
2408 int ret;
2409 spin_lock(&res->spinlock);
2410 ret = !!(res->state & DLM_LOCK_RES_DIRTY);
2411 spin_unlock(&res->spinlock);
2412 return ret;
2413}
2414
2415
2416static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
2417 struct dlm_lock_resource *res,
2418 u8 target)
2419{
2420 int ret = 0;
2421
2422 mlog(0, "dlm_mark_lockres_migrating: %.*s, from %u to %u\n",
2423 res->lockname.len, res->lockname.name, dlm->node_num,
2424 target);
2425 /* need to set MIGRATING flag on lockres. this is done by
2426 * ensuring that all asts have been flushed for this lockres. */
2427 spin_lock(&res->spinlock);
2428 BUG_ON(res->migration_pending);
2429 res->migration_pending = 1;
2430 /* strategy is to reserve an extra ast then release
2431 * it below, letting the release do all of the work */
2432 __dlm_lockres_reserve_ast(res);
2433 spin_unlock(&res->spinlock);
2434
2435 /* now flush all the pending asts.. hang out for a bit */
2436 dlm_kick_thread(dlm, res);
2437 wait_event(dlm->ast_wq, !dlm_lockres_is_dirty(dlm, res));
2438 dlm_lockres_release_ast(dlm, res);
2439
2440 mlog(0, "about to wait on migration_wq, dirty=%s\n",
2441 res->state & DLM_LOCK_RES_DIRTY ? "yes" : "no");
2442 /* if the extra ref we just put was the final one, this
2443 * will pass thru immediately. otherwise, we need to wait
2444 * for the last ast to finish. */
2445again:
2446 ret = wait_event_interruptible_timeout(dlm->migration_wq,
2447 dlm_migration_can_proceed(dlm, res, target),
2448 msecs_to_jiffies(1000));
2449 if (ret < 0) {
2450 mlog(0, "woken again: migrating? %s, dead? %s\n",
2451 res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
2452 test_bit(target, dlm->domain_map) ? "no":"yes");
2453 } else {
2454 mlog(0, "all is well: migrating? %s, dead? %s\n",
2455 res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
2456 test_bit(target, dlm->domain_map) ? "no":"yes");
2457 }
2458 if (!dlm_migration_can_proceed(dlm, res, target)) {
2459 mlog(0, "trying again...\n");
2460 goto again;
2461 }
2462
2463 /* did the target go down or die? */
2464 spin_lock(&dlm->spinlock);
2465 if (!test_bit(target, dlm->domain_map)) {
2466 mlog(ML_ERROR, "aha. migration target %u just went down\n",
2467 target);
2468 ret = -EHOSTDOWN;
2469 }
2470 spin_unlock(&dlm->spinlock);
2471
2472 /*
2473 * at this point:
2474 *
2475 * o the DLM_LOCK_RES_MIGRATING flag is set
2476 * o there are no pending asts on this lockres
2477 * o all processes trying to reserve an ast on this
2478 * lockres must wait for the MIGRATING flag to clear
2479 */
2480 return ret;
2481}
2482
2483/* last step in the migration process.
2484 * original master calls this to free all of the dlm_lock
2485 * structures that used to be for other nodes. */
2486static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
2487 struct dlm_lock_resource *res)
2488{
2489 struct list_head *iter, *iter2;
2490 struct list_head *queue = &res->granted;
2491 int i;
2492 struct dlm_lock *lock;
2493
2494 assert_spin_locked(&res->spinlock);
2495
2496 BUG_ON(res->owner == dlm->node_num);
2497
2498 for (i=0; i<3; i++) {
2499 list_for_each_safe(iter, iter2, queue) {
2500 lock = list_entry (iter, struct dlm_lock, list);
2501 if (lock->ml.node != dlm->node_num) {
2502 mlog(0, "putting lock for node %u\n",
2503 lock->ml.node);
2504 /* be extra careful */
2505 BUG_ON(!list_empty(&lock->ast_list));
2506 BUG_ON(!list_empty(&lock->bast_list));
2507 BUG_ON(lock->ast_pending);
2508 BUG_ON(lock->bast_pending);
2509 list_del_init(&lock->list);
2510 dlm_lock_put(lock);
2511 }
2512 }
2513 queue++;
2514 }
2515}
2516
2517/* for now this is not too intelligent. we will
2518 * need stats to make this do the right thing.
2519 * this just finds the first lock on one of the
2520 * queues and uses that node as the target. */
2521static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
2522 struct dlm_lock_resource *res)
2523{
2524 int i;
2525 struct list_head *queue = &res->granted;
2526 struct list_head *iter;
2527 struct dlm_lock *lock;
2528 int nodenum;
2529
2530 assert_spin_locked(&dlm->spinlock);
2531
2532 spin_lock(&res->spinlock);
2533 for (i=0; i<3; i++) {
2534 list_for_each(iter, queue) {
2535 /* up to the caller to make sure this node
2536 * is alive */
2537 lock = list_entry (iter, struct dlm_lock, list);
2538 if (lock->ml.node != dlm->node_num) {
2539 spin_unlock(&res->spinlock);
2540 return lock->ml.node;
2541 }
2542 }
2543 queue++;
2544 }
2545 spin_unlock(&res->spinlock);
2546 mlog(0, "have not found a suitable target yet! checking domain map\n");
2547
2548 /* ok now we're getting desperate. pick anyone alive. */
2549 nodenum = -1;
2550 while (1) {
2551 nodenum = find_next_bit(dlm->domain_map,
2552 O2NM_MAX_NODES, nodenum+1);
2553 mlog(0, "found %d in domain map\n", nodenum);
2554 if (nodenum >= O2NM_MAX_NODES)
2555 break;
2556 if (nodenum != dlm->node_num) {
2557 mlog(0, "picking %d\n", nodenum);
2558 return nodenum;
2559 }
2560 }
2561
2562 mlog(0, "giving up. no master to migrate to\n");
2563 return DLM_LOCK_RES_OWNER_UNKNOWN;
2564}
2565
2566
2567
2568/* this is called by the new master once all lockres
2569 * data has been received */
2570static int dlm_do_migrate_request(struct dlm_ctxt *dlm,
2571 struct dlm_lock_resource *res,
2572 u8 master, u8 new_master,
2573 struct dlm_node_iter *iter)
2574{
2575 struct dlm_migrate_request migrate;
2576 int ret, status = 0;
2577 int nodenum;
2578
2579 memset(&migrate, 0, sizeof(migrate));
2580 migrate.namelen = res->lockname.len;
2581 memcpy(migrate.name, res->lockname.name, migrate.namelen);
2582 migrate.new_master = new_master;
2583 migrate.master = master;
2584
2585 ret = 0;
2586
2587 /* send message to all nodes, except the master and myself */
2588 while ((nodenum = dlm_node_iter_next(iter)) >= 0) {
2589 if (nodenum == master ||
2590 nodenum == new_master)
2591 continue;
2592
2593 ret = o2net_send_message(DLM_MIGRATE_REQUEST_MSG, dlm->key,
2594 &migrate, sizeof(migrate), nodenum,
2595 &status);
2596 if (ret < 0)
2597 mlog_errno(ret);
2598 else if (status < 0) {
2599 mlog(0, "migrate request (node %u) returned %d!\n",
2600 nodenum, status);
2601 ret = status;
2602 }
2603 }
2604
2605 if (ret < 0)
2606 mlog_errno(ret);
2607
2608 mlog(0, "returning ret=%d\n", ret);
2609 return ret;
2610}
2611
2612
2613/* if there is an existing mle for this lockres, we now know who the master is.
2614 * (the one who sent us *this* message) we can clear it up right away.
2615 * since the process that put the mle on the list still has a reference to it,
2616 * we can unhash it now, set the master and wake the process. as a result,
2617 * we will have no mle in the list to start with. now we can add an mle for
2618 * the migration and this should be the only one found for those scanning the
2619 * list. */
2620int dlm_migrate_request_handler(struct o2net_msg *msg, u32 len, void *data)
2621{
2622 struct dlm_ctxt *dlm = data;
2623 struct dlm_lock_resource *res = NULL;
2624 struct dlm_migrate_request *migrate = (struct dlm_migrate_request *) msg->buf;
2625 struct dlm_master_list_entry *mle = NULL, *oldmle = NULL;
2626 const char *name;
a3d33291 2627 unsigned int namelen, hash;
6714d8e8
KH		 2628 int ret = 0;
2629
2630 if (!dlm_grab(dlm))
2631 return -EINVAL;
2632
2633 name = migrate->name;
2634 namelen = migrate->namelen;
a3d33291 2635 hash = dlm_lockid_hash(name, namelen);
6714d8e8
KH		 2636
2637 /* preallocate.. if this fails, abort */
2638 mle = (struct dlm_master_list_entry *) kmem_cache_alloc(dlm_mle_cache,
2639 GFP_KERNEL);
2640
2641 if (!mle) {
2642 ret = -ENOMEM;
2643 goto leave;
2644 }
2645
2646 /* check for pre-existing lock */
2647 spin_lock(&dlm->spinlock);
a3d33291 2648 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
6714d8e8
KH		 2649 spin_lock(&dlm->master_lock);
2650
2651 if (res) {
2652 spin_lock(&res->spinlock);
2653 if (res->state & DLM_LOCK_RES_RECOVERING) {
2654 /* if all is working ok, this can only mean that we got
2655 * a migrate request from a node that we now see as
2656 * dead. what can we do here? drop it to the floor? */
2657 spin_unlock(&res->spinlock);
2658 mlog(ML_ERROR, "Got a migrate request, but the "
2659 "lockres is marked as recovering!");
2660 kmem_cache_free(dlm_mle_cache, mle);
2661 ret = -EINVAL; /* need a better solution */
2662 goto unlock;
2663 }
2664 res->state |= DLM_LOCK_RES_MIGRATING;
2665 spin_unlock(&res->spinlock);
2666 }
2667
2668 /* ignore status. only nonzero status would BUG. */
2669 ret = dlm_add_migration_mle(dlm, res, mle, &oldmle,
2670 name, namelen,
2671 migrate->new_master,
2672 migrate->master);
2673
2674unlock:
2675 spin_unlock(&dlm->master_lock);
2676 spin_unlock(&dlm->spinlock);
2677
2678 if (oldmle) {
2679 /* master is known, detach if not already detached */
2680 dlm_mle_detach_hb_events(dlm, oldmle);
2681 dlm_put_mle(oldmle);
2682 }
2683
2684 if (res)
2685 dlm_lockres_put(res);
2686leave:
2687 dlm_put(dlm);
2688 return ret;
2689}
2690
2691/* must be holding dlm->spinlock and dlm->master_lock
2692 * when adding a migration mle, we can clear any other mles
2693 * in the master list because we know with certainty that
2694 * the master is "master". so we remove any old mle from
2695 * the list after setting it's master field, and then add
2696 * the new migration mle. this way we can hold with the rule
2697 * of having only one mle for a given lock name at all times. */
2698static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
2699 struct dlm_lock_resource *res,
2700 struct dlm_master_list_entry *mle,
2701 struct dlm_master_list_entry **oldmle,
2702 const char *name, unsigned int namelen,
2703 u8 new_master, u8 master)
2704{
2705 int found;
2706 int ret = 0;
2707
2708 *oldmle = NULL;
2709
2710 mlog_entry_void();
2711
2712 assert_spin_locked(&dlm->spinlock);
2713 assert_spin_locked(&dlm->master_lock);
2714
2715 /* caller is responsible for any ref taken here on oldmle */
2716 found = dlm_find_mle(dlm, oldmle, (char *)name, namelen);
2717 if (found) {
2718 struct dlm_master_list_entry *tmp = *oldmle;
2719 spin_lock(&tmp->spinlock);
2720 if (tmp->type == DLM_MLE_MIGRATION) {
2721 if (master == dlm->node_num) {
2722 /* ah another process raced me to it */
2723 mlog(0, "tried to migrate %.*s, but some "
2724 "process beat me to it\n",
2725 namelen, name);
2726 ret = -EEXIST;
2727 } else {
2728 /* bad. 2 NODES are trying to migrate! */
2729 mlog(ML_ERROR, "migration error mle: "
2730 "master=%u new_master=%u // request: "
2731 "master=%u new_master=%u // "
2732 "lockres=%.*s\n",
2733 tmp->master, tmp->new_master,
2734 master, new_master,
2735 namelen, name);
2736 BUG();
2737 }
2738 } else {
2739 /* this is essentially what assert_master does */
2740 tmp->master = master;
2741 atomic_set(&tmp->woken, 1);
2742 wake_up(&tmp->wq);
2743 /* remove it from the list so that only one
2744 * mle will be found */
2745 list_del_init(&tmp->list);
da01ad05 2746 __dlm_mle_detach_hb_events(dlm, mle);
6714d8e8
KH		 2747 }
2748 spin_unlock(&tmp->spinlock);
2749 }
2750
2751 /* now add a migration mle to the tail of the list */
2752 dlm_init_mle(mle, DLM_MLE_MIGRATION, dlm, res, name, namelen);
2753 mle->new_master = new_master;
2754 mle->master = master;
2755 /* do this for consistency with other mle types */
2756 set_bit(new_master, mle->maybe_map);
2757 list_add(&mle->list, &dlm->master_list);
2758
2759 return ret;
2760}
2761
2762
2763void dlm_clean_master_list(struct dlm_ctxt *dlm, u8 dead_node)
2764{
2765 struct list_head *iter, *iter2;
2766 struct dlm_master_list_entry *mle;
2767 struct dlm_lock_resource *res;
a3d33291 2768 unsigned int hash;
6714d8e8
KH		 2769
2770 mlog_entry("dlm=%s, dead node=%u\n", dlm->name, dead_node);
2771top:
2772 assert_spin_locked(&dlm->spinlock);
2773
2774 /* clean the master list */
2775 spin_lock(&dlm->master_lock);
2776 list_for_each_safe(iter, iter2, &dlm->master_list) {
2777 mle = list_entry(iter, struct dlm_master_list_entry, list);
2778
2779 BUG_ON(mle->type != DLM_MLE_BLOCK &&
2780 mle->type != DLM_MLE_MASTER &&
2781 mle->type != DLM_MLE_MIGRATION);
2782
2783 /* MASTER mles are initiated locally. the waiting
2784 * process will notice the node map change
2785 * shortly. let that happen as normal. */
2786 if (mle->type == DLM_MLE_MASTER)
2787 continue;
2788
2789
2790 /* BLOCK mles are initiated by other nodes.
2791 * need to clean up if the dead node would have
2792 * been the master. */
2793 if (mle->type == DLM_MLE_BLOCK) {
2794 int bit;
2795
2796 spin_lock(&mle->spinlock);
2797 bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
2798 if (bit != dead_node) {
2799 mlog(0, "mle found, but dead node %u would "
2800 "not have been master\n", dead_node);
2801 spin_unlock(&mle->spinlock);
2802 } else {
2803 /* must drop the refcount by one since the
2804 * assert_master will never arrive. this
2805 * may result in the mle being unlinked and
2806 * freed, but there may still be a process
2807 * waiting in the dlmlock path which is fine. */
2808 mlog(ML_ERROR, "node %u was expected master\n",
2809 dead_node);
2810 atomic_set(&mle->woken, 1);
2811 spin_unlock(&mle->spinlock);
2812 wake_up(&mle->wq);
f671c09b
KH		 2813 /* do not need events any longer, so detach
2814 * from heartbeat */
2815 __dlm_mle_detach_hb_events(dlm, mle);
6714d8e8
KH		 2816 __dlm_put_mle(mle);
2817 }
2818 continue;
2819 }
2820
2821 /* everything else is a MIGRATION mle */
2822
2823 /* the rule for MIGRATION mles is that the master
2824 * becomes UNKNOWN if *either* the original or
2825 * the new master dies. all UNKNOWN lockreses
2826 * are sent to whichever node becomes the recovery
2827 * master. the new master is responsible for
2828 * determining if there is still a master for
2829 * this lockres, or if he needs to take over
2830 * mastery. either way, this node should expect
2831 * another message to resolve this. */
2832 if (mle->master != dead_node &&
2833 mle->new_master != dead_node)
2834 continue;
2835
2836 /* if we have reached this point, this mle needs to
2837 * be removed from the list and freed. */
2838
2839 /* remove from the list early. NOTE: unlinking
2840 * list_head while in list_for_each_safe */
da01ad05 2841 __dlm_mle_detach_hb_events(dlm, mle);
6714d8e8
KH		 2842 spin_lock(&mle->spinlock);
2843 list_del_init(&mle->list);
2844 atomic_set(&mle->woken, 1);
2845 spin_unlock(&mle->spinlock);
2846 wake_up(&mle->wq);
2847
aa852354
KH		 2848 mlog(0, "%s: node %u died during migration from "
2849 "%u to %u!\n", dlm->name, dead_node,
6714d8e8
KH		 2850 mle->master, mle->new_master);
2851 /* if there is a lockres associated with this
2852 * mle, find it and set its owner to UNKNOWN */
a3d33291 2853 hash = dlm_lockid_hash(mle->u.name.name, mle->u.name.len);
6714d8e8 2854 res = __dlm_lookup_lockres(dlm, mle->u.name.name,
a3d33291 2855 mle->u.name.len, hash);
6714d8e8
KH		 2856 if (res) {
2857 /* unfortunately if we hit this rare case, our
2858 * lock ordering is messed. we need to drop
2859 * the master lock so that we can take the
2860 * lockres lock, meaning that we will have to
2861 * restart from the head of list. */
2862 spin_unlock(&dlm->master_lock);
2863
2864 /* move lockres onto recovery list */
2865 spin_lock(&res->spinlock);
2866 dlm_set_lockres_owner(dlm, res,
2867 DLM_LOCK_RES_OWNER_UNKNOWN);
2868 dlm_move_lockres_to_recovery_list(dlm, res);
2869 spin_unlock(&res->spinlock);
2870 dlm_lockres_put(res);
2871
f671c09b
KH		 2872 /* about to get rid of mle, detach from heartbeat */
2873 __dlm_mle_detach_hb_events(dlm, mle);
2874
6714d8e8
KH		 2875 /* dump the mle */
2876 spin_lock(&dlm->master_lock);
2877 __dlm_put_mle(mle);
2878 spin_unlock(&dlm->master_lock);
2879
2880 /* restart */
2881 goto top;
2882 }
2883
2884 /* this may be the last reference */
2885 __dlm_put_mle(mle);
2886 }
2887 spin_unlock(&dlm->master_lock);
2888}
2889
2890
2891int dlm_finish_migration(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
2892 u8 old_master)
2893{
2894 struct dlm_node_iter iter;
2895 int ret = 0;
2896
2897 spin_lock(&dlm->spinlock);
2898 dlm_node_iter_init(dlm->domain_map, &iter);
2899 clear_bit(old_master, iter.node_map);
2900 clear_bit(dlm->node_num, iter.node_map);
2901 spin_unlock(&dlm->spinlock);
2902
2903 mlog(0, "now time to do a migrate request to other nodes\n");
2904 ret = dlm_do_migrate_request(dlm, res, old_master,
2905 dlm->node_num, &iter);
2906 if (ret < 0) {
2907 mlog_errno(ret);
2908 goto leave;
2909 }
2910
2911 mlog(0, "doing assert master of %.*s to all except the original node\n",
2912 res->lockname.len, res->lockname.name);
2913 /* this call now finishes out the nodemap
2914 * even if one or more nodes die */
2915 ret = dlm_do_assert_master(dlm, res->lockname.name,
2916 res->lockname.len, iter.node_map,
2917 DLM_ASSERT_MASTER_FINISH_MIGRATION);
2918 if (ret < 0) {
2919 /* no longer need to retry. all living nodes contacted. */
2920 mlog_errno(ret);
2921 ret = 0;
2922 }
2923
2924 memset(iter.node_map, 0, sizeof(iter.node_map));
2925 set_bit(old_master, iter.node_map);
2926 mlog(0, "doing assert master of %.*s back to %u\n",
2927 res->lockname.len, res->lockname.name, old_master);
2928 ret = dlm_do_assert_master(dlm, res->lockname.name,
2929 res->lockname.len, iter.node_map,
2930 DLM_ASSERT_MASTER_FINISH_MIGRATION);
2931 if (ret < 0) {
2932 mlog(0, "assert master to original master failed "
2933 "with %d.\n", ret);
2934 /* the only nonzero status here would be because of
2935 * a dead original node. we're done. */
2936 ret = 0;
2937 }
2938
2939 /* all done, set the owner, clear the flag */
2940 spin_lock(&res->spinlock);
2941 dlm_set_lockres_owner(dlm, res, dlm->node_num);
2942 res->state &= ~DLM_LOCK_RES_MIGRATING;
2943 spin_unlock(&res->spinlock);
2944 /* re-dirty it on the new master */
2945 dlm_kick_thread(dlm, res);
2946 wake_up(&res->wq);
2947leave:
2948 return ret;
2949}
2950
2951/*
2952 * LOCKRES AST REFCOUNT
2953 * this is integral to migration
2954 */
2955
2956/* for future intent to call an ast, reserve one ahead of time.
2957 * this should be called only after waiting on the lockres
2958 * with dlm_wait_on_lockres, and while still holding the
2959 * spinlock after the call. */
2960void __dlm_lockres_reserve_ast(struct dlm_lock_resource *res)
2961{
2962 assert_spin_locked(&res->spinlock);
2963 if (res->state & DLM_LOCK_RES_MIGRATING) {
2964 __dlm_print_one_lock_resource(res);
2965 }
2966 BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
2967
2968 atomic_inc(&res->asts_reserved);
2969}
2970
2971/*
2972 * used to drop the reserved ast, either because it went unused,
2973 * or because the ast/bast was actually called.
2974 *
2975 * also, if there is a pending migration on this lockres,
2976 * and this was the last pending ast on the lockres,
2977 * atomically set the MIGRATING flag before we drop the lock.
2978 * this is how we ensure that migration can proceed with no
2979 * asts in progress. note that it is ok if the state of the
2980 * queues is such that a lock should be granted in the future
2981 * or that a bast should be fired, because the new master will
2982 * shuffle the lists on this lockres as soon as it is migrated.
2983 */
2984void dlm_lockres_release_ast(struct dlm_ctxt *dlm,
2985 struct dlm_lock_resource *res)
2986{
2987 if (!atomic_dec_and_lock(&res->asts_reserved, &res->spinlock))
2988 return;
2989
2990 if (!res->migration_pending) {
2991 spin_unlock(&res->spinlock);
2992 return;
2993 }
2994
2995 BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
2996 res->migration_pending = 0;
2997 res->state |= DLM_LOCK_RES_MIGRATING;
2998 spin_unlock(&res->spinlock);
2999 wake_up(&res->wq);
3000 wake_up(&dlm->migration_wq);
3001}
Linux 6.x block layer and io_uring tree(s)