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ocfs2: fix incorrect error returns
[linux-2.6-block.git] / fs / ocfs2 / dlm / dlmmaster.c
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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
ad8100e0 712 res = kmalloc(sizeof(struct dlm_lock_resource), GFP_NOFS);
6714d8e8
KH		 713 if (!res)
714 return NULL;
715
ad8100e0 716 res->lockname.name = kmalloc(namelen, GFP_NOFS);
6714d8e8
KH		 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 *)
ad8100e0 780 kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
6714d8e8
KH		 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);
b7084ab5
KH		 902
903 if (wait_on_recovery)
904 dlm_wait_for_node_recovery(dlm, bit, 10000);
c03872f5
KH		 905 }
906
6714d8e8
KH		 907 /* must wait for lock to be mastered elsewhere */
908 if (blocked)
909 goto wait;
910
6714d8e8
KH		 911 ret = -EINVAL;
912 dlm_node_iter_init(mle->vote_map, &iter);
913 while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
914 ret = dlm_do_master_request(mle, nodenum);
915 if (ret < 0)
916 mlog_errno(ret);
917 if (mle->master != O2NM_MAX_NODES) {
918 /* found a master ! */
9c6510a5
KH		 919 if (mle->master <= nodenum)
920 break;
921 /* if our master request has not reached the master
922 * yet, keep going until it does. this is how the
923 * master will know that asserts are needed back to
924 * the lower nodes. */
925 mlog(0, "%s:%.*s: requests only up to %u but master "
926 "is %u, keep going\n", dlm->name, namelen,
927 lockid, nodenum, mle->master);
6714d8e8
KH		 928 }
929 }
930
931wait:
932 /* keep going until the response map includes all nodes */
933 ret = dlm_wait_for_lock_mastery(dlm, res, mle, &blocked);
934 if (ret < 0) {
e7e69eb3 935 wait_on_recovery = 1;
6714d8e8
KH		 936 mlog(0, "%s:%.*s: node map changed, redo the "
937 "master request now, blocked=%d\n",
938 dlm->name, res->lockname.len,
939 res->lockname.name, blocked);
940 if (++tries > 20) {
941 mlog(ML_ERROR, "%s:%.*s: spinning on "
942 "dlm_wait_for_lock_mastery, blocked=%d\n",
943 dlm->name, res->lockname.len,
944 res->lockname.name, blocked);
945 dlm_print_one_lock_resource(res);
946 /* dlm_print_one_mle(mle); */
947 tries = 0;
948 }
949 goto redo_request;
950 }
951
952 mlog(0, "lockres mastered by %u\n", res->owner);
953 /* make sure we never continue without this */
954 BUG_ON(res->owner == O2NM_MAX_NODES);
955
956 /* master is known, detach if not already detached */
957 dlm_mle_detach_hb_events(dlm, mle);
958 dlm_put_mle(mle);
959 /* put the extra ref */
a2bf0477 960 dlm_put_mle_inuse(mle);
6714d8e8
KH		 961
962wake_waiters:
963 spin_lock(&res->spinlock);
964 res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
965 spin_unlock(&res->spinlock);
966 wake_up(&res->wq);
967
968leave:
969 /* need to free the unused mle */
970 if (alloc_mle)
971 kmem_cache_free(dlm_mle_cache, alloc_mle);
972
973 return res;
974}
975
976
977#define DLM_MASTERY_TIMEOUT_MS 5000
978
979static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
980 struct dlm_lock_resource *res,
981 struct dlm_master_list_entry *mle,
982 int *blocked)
983{
984 u8 m;
985 int ret, bit;
986 int map_changed, voting_done;
987 int assert, sleep;
988
989recheck:
990 ret = 0;
991 assert = 0;
992
993 /* check if another node has already become the owner */
994 spin_lock(&res->spinlock);
995 if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
9c6510a5
KH		 996 mlog(0, "%s:%.*s: owner is suddenly %u\n", dlm->name,
997 res->lockname.len, res->lockname.name, res->owner);
6714d8e8 998 spin_unlock(&res->spinlock);
9c6510a5
KH		 999 /* this will cause the master to re-assert across
1000 * the whole cluster, freeing up mles */
588e0090
KH		 1001 if (res->owner != dlm->node_num) {
1002 ret = dlm_do_master_request(mle, res->owner);
1003 if (ret < 0) {
1004 /* give recovery a chance to run */
1005 mlog(ML_ERROR, "link to %u went down?: %d\n", res->owner, ret);
1006 msleep(500);
1007 goto recheck;
1008 }
9c6510a5
KH		 1009 }
1010 ret = 0;
6714d8e8
KH		 1011 goto leave;
1012 }
1013 spin_unlock(&res->spinlock);
1014
1015 spin_lock(&mle->spinlock);
1016 m = mle->master;
1017 map_changed = (memcmp(mle->vote_map, mle->node_map,
1018 sizeof(mle->vote_map)) != 0);
1019 voting_done = (memcmp(mle->vote_map, mle->response_map,
1020 sizeof(mle->vote_map)) == 0);
1021
1022 /* restart if we hit any errors */
1023 if (map_changed) {
1024 int b;
1025 mlog(0, "%s: %.*s: node map changed, restarting\n",
1026 dlm->name, res->lockname.len, res->lockname.name);
1027 ret = dlm_restart_lock_mastery(dlm, res, mle, *blocked);
1028 b = (mle->type == DLM_MLE_BLOCK);
1029 if ((*blocked && !b) || (!*blocked && b)) {
1030 mlog(0, "%s:%.*s: status change: old=%d new=%d\n",
1031 dlm->name, res->lockname.len, res->lockname.name,
1032 *blocked, b);
1033 *blocked = b;
1034 }
1035 spin_unlock(&mle->spinlock);
1036 if (ret < 0) {
1037 mlog_errno(ret);
1038 goto leave;
1039 }
1040 mlog(0, "%s:%.*s: restart lock mastery succeeded, "
1041 "rechecking now\n", dlm->name, res->lockname.len,
1042 res->lockname.name);
1043 goto recheck;
aa852354
KH		 1044 } else {
1045 if (!voting_done) {
1046 mlog(0, "map not changed and voting not done "
1047 "for %s:%.*s\n", dlm->name, res->lockname.len,
1048 res->lockname.name);
1049 }
6714d8e8
KH		 1050 }
1051
1052 if (m != O2NM_MAX_NODES) {
1053 /* another node has done an assert!
1054 * all done! */
1055 sleep = 0;
1056 } else {
1057 sleep = 1;
1058 /* have all nodes responded? */
1059 if (voting_done && !*blocked) {
1060 bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
1061 if (dlm->node_num <= bit) {
1062 /* my node number is lowest.
1063 * now tell other nodes that I am
1064 * mastering this. */
1065 mle->master = dlm->node_num;
1066 assert = 1;
1067 sleep = 0;
1068 }
1069 /* if voting is done, but we have not received
1070 * an assert master yet, we must sleep */
1071 }
1072 }
1073
1074 spin_unlock(&mle->spinlock);
1075
1076 /* sleep if we haven't finished voting yet */
1077 if (sleep) {
1078 unsigned long timeo = msecs_to_jiffies(DLM_MASTERY_TIMEOUT_MS);
1079
1080 /*
1081 if (atomic_read(&mle->mle_refs.refcount) < 2)
1082 mlog(ML_ERROR, "mle (%p) refs=%d, name=%.*s\n", mle,
1083 atomic_read(&mle->mle_refs.refcount),
1084 res->lockname.len, res->lockname.name);
1085 */
1086 atomic_set(&mle->woken, 0);
1087 (void)wait_event_timeout(mle->wq,
1088 (atomic_read(&mle->woken) == 1),
1089 timeo);
1090 if (res->owner == O2NM_MAX_NODES) {
1091 mlog(0, "waiting again\n");
1092 goto recheck;
1093 }
1094 mlog(0, "done waiting, master is %u\n", res->owner);
1095 ret = 0;
1096 goto leave;
1097 }
1098
1099 ret = 0; /* done */
1100 if (assert) {
1101 m = dlm->node_num;
1102 mlog(0, "about to master %.*s here, this=%u\n",
1103 res->lockname.len, res->lockname.name, m);
1104 ret = dlm_do_assert_master(dlm, res->lockname.name,
1105 res->lockname.len, mle->vote_map, 0);
1106 if (ret) {
1107 /* This is a failure in the network path,
1108 * not in the response to the assert_master
1109 * (any nonzero response is a BUG on this node).
1110 * Most likely a socket just got disconnected
1111 * due to node death. */
1112 mlog_errno(ret);
1113 }
1114 /* no longer need to restart lock mastery.
1115 * all living nodes have been contacted. */
1116 ret = 0;
1117 }
1118
1119 /* set the lockres owner */
1120 spin_lock(&res->spinlock);
1121 dlm_change_lockres_owner(dlm, res, m);
1122 spin_unlock(&res->spinlock);
1123
1124leave:
1125 return ret;
1126}
1127
1128struct dlm_bitmap_diff_iter
1129{
1130 int curnode;
1131 unsigned long *orig_bm;
1132 unsigned long *cur_bm;
1133 unsigned long diff_bm[BITS_TO_LONGS(O2NM_MAX_NODES)];
1134};
1135
1136enum dlm_node_state_change
1137{
1138 NODE_DOWN = -1,
1139 NODE_NO_CHANGE = 0,
1140 NODE_UP
1141};
1142
1143static void dlm_bitmap_diff_iter_init(struct dlm_bitmap_diff_iter *iter,
1144 unsigned long *orig_bm,
1145 unsigned long *cur_bm)
1146{
1147 unsigned long p1, p2;
1148 int i;
1149
1150 iter->curnode = -1;
1151 iter->orig_bm = orig_bm;
1152 iter->cur_bm = cur_bm;
1153
1154 for (i = 0; i < BITS_TO_LONGS(O2NM_MAX_NODES); i++) {
1155 p1 = *(iter->orig_bm + i);
1156 p2 = *(iter->cur_bm + i);
1157 iter->diff_bm[i] = (p1 & ~p2) | (p2 & ~p1);
1158 }
1159}
1160
1161static int dlm_bitmap_diff_iter_next(struct dlm_bitmap_diff_iter *iter,
1162 enum dlm_node_state_change *state)
1163{
1164 int bit;
1165
1166 if (iter->curnode >= O2NM_MAX_NODES)
1167 return -ENOENT;
1168
1169 bit = find_next_bit(iter->diff_bm, O2NM_MAX_NODES,
1170 iter->curnode+1);
1171 if (bit >= O2NM_MAX_NODES) {
1172 iter->curnode = O2NM_MAX_NODES;
1173 return -ENOENT;
1174 }
1175
1176 /* if it was there in the original then this node died */
1177 if (test_bit(bit, iter->orig_bm))
1178 *state = NODE_DOWN;
1179 else
1180 *state = NODE_UP;
1181
1182 iter->curnode = bit;
1183 return bit;
1184}
1185
1186
1187static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
1188 struct dlm_lock_resource *res,
1189 struct dlm_master_list_entry *mle,
1190 int blocked)
1191{
1192 struct dlm_bitmap_diff_iter bdi;
1193 enum dlm_node_state_change sc;
1194 int node;
1195 int ret = 0;
1196
1197 mlog(0, "something happened such that the "
1198 "master process may need to be restarted!\n");
1199
1200 assert_spin_locked(&mle->spinlock);
1201
1202 dlm_bitmap_diff_iter_init(&bdi, mle->vote_map, mle->node_map);
1203 node = dlm_bitmap_diff_iter_next(&bdi, &sc);
1204 while (node >= 0) {
1205 if (sc == NODE_UP) {
e2faea4c
KH		 1206 /* a node came up. clear any old vote from
1207 * the response map and set it in the vote map
1208 * then restart the mastery. */
1209 mlog(ML_NOTICE, "node %d up while restarting\n", node);
6714d8e8
KH		 1210
1211 /* redo the master request, but only for the new node */
1212 mlog(0, "sending request to new node\n");
1213 clear_bit(node, mle->response_map);
1214 set_bit(node, mle->vote_map);
1215 } else {
1216 mlog(ML_ERROR, "node down! %d\n", node);
6714d8e8
KH		 1217 if (blocked) {
1218 int lowest = find_next_bit(mle->maybe_map,
1219 O2NM_MAX_NODES, 0);
1220
1221 /* act like it was never there */
1222 clear_bit(node, mle->maybe_map);
1223
e7e69eb3
KH		 1224 if (node == lowest) {
1225 mlog(0, "expected master %u died"
1226 " while this node was blocked "
1227 "waiting on it!\n", node);
1228 lowest = find_next_bit(mle->maybe_map,
1229 O2NM_MAX_NODES,
1230 lowest+1);
1231 if (lowest < O2NM_MAX_NODES) {
1232 mlog(0, "%s:%.*s:still "
1233 "blocked. waiting on %u "
1234 "now\n", dlm->name,
1235 res->lockname.len,
1236 res->lockname.name,
1237 lowest);
1238 } else {
1239 /* mle is an MLE_BLOCK, but
1240 * there is now nothing left to
1241 * block on. we need to return
1242 * all the way back out and try
1243 * again with an MLE_MASTER.
1244 * dlm_do_local_recovery_cleanup
1245 * has already run, so the mle
1246 * refcount is ok */
1247 mlog(0, "%s:%.*s: no "
1248 "longer blocking. try to "
1249 "master this here\n",
1250 dlm->name,
1251 res->lockname.len,
1252 res->lockname.name);
1253 mle->type = DLM_MLE_MASTER;
1254 mle->u.res = res;
1255 }
6714d8e8 1256 }
6714d8e8
KH		 1257 }
1258
e7e69eb3
KH		 1259 /* now blank out everything, as if we had never
1260 * contacted anyone */
1261 memset(mle->maybe_map, 0, sizeof(mle->maybe_map));
1262 memset(mle->response_map, 0, sizeof(mle->response_map));
1263 /* reset the vote_map to the current node_map */
1264 memcpy(mle->vote_map, mle->node_map,
1265 sizeof(mle->node_map));
1266 /* put myself into the maybe map */
1267 if (mle->type != DLM_MLE_BLOCK)
1268 set_bit(dlm->node_num, mle->maybe_map);
6714d8e8
KH		 1269 }
1270 ret = -EAGAIN;
6714d8e8
KH		 1271 node = dlm_bitmap_diff_iter_next(&bdi, &sc);
1272 }
1273 return ret;
1274}
1275
1276
1277/*
1278 * DLM_MASTER_REQUEST_MSG
1279 *
1280 * returns: 0 on success,
1281 * -errno on a network error
1282 *
1283 * on error, the caller should assume the target node is "dead"
1284 *
1285 */
1286
1287static int dlm_do_master_request(struct dlm_master_list_entry *mle, int to)
1288{
1289 struct dlm_ctxt *dlm = mle->dlm;
1290 struct dlm_master_request request;
1291 int ret, response=0, resend;
1292
1293 memset(&request, 0, sizeof(request));
1294 request.node_idx = dlm->node_num;
1295
1296 BUG_ON(mle->type == DLM_MLE_MIGRATION);
1297
1298 if (mle->type != DLM_MLE_MASTER) {
1299 request.namelen = mle->u.name.len;
1300 memcpy(request.name, mle->u.name.name, request.namelen);
1301 } else {
1302 request.namelen = mle->u.res->lockname.len;
1303 memcpy(request.name, mle->u.res->lockname.name,
1304 request.namelen);
1305 }
1306
1307again:
1308 ret = o2net_send_message(DLM_MASTER_REQUEST_MSG, dlm->key, &request,
1309 sizeof(request), to, &response);
1310 if (ret < 0) {
1311 if (ret == -ESRCH) {
1312 /* should never happen */
1313 mlog(ML_ERROR, "TCP stack not ready!\n");
1314 BUG();
1315 } else if (ret == -EINVAL) {
1316 mlog(ML_ERROR, "bad args passed to o2net!\n");
1317 BUG();
1318 } else if (ret == -ENOMEM) {
1319 mlog(ML_ERROR, "out of memory while trying to send "
1320 "network message! retrying\n");
1321 /* this is totally crude */
1322 msleep(50);
1323 goto again;
1324 } else if (!dlm_is_host_down(ret)) {
1325 /* not a network error. bad. */
1326 mlog_errno(ret);
1327 mlog(ML_ERROR, "unhandled error!");
1328 BUG();
1329 }
1330 /* all other errors should be network errors,
1331 * and likely indicate node death */
1332 mlog(ML_ERROR, "link to %d went down!\n", to);
1333 goto out;
1334 }
1335
1336 ret = 0;
1337 resend = 0;
1338 spin_lock(&mle->spinlock);
1339 switch (response) {
1340 case DLM_MASTER_RESP_YES:
1341 set_bit(to, mle->response_map);
1342 mlog(0, "node %u is the master, response=YES\n", to);
1343 mle->master = to;
1344 break;
1345 case DLM_MASTER_RESP_NO:
1346 mlog(0, "node %u not master, response=NO\n", to);
1347 set_bit(to, mle->response_map);
1348 break;
1349 case DLM_MASTER_RESP_MAYBE:
1350 mlog(0, "node %u not master, response=MAYBE\n", to);
1351 set_bit(to, mle->response_map);
1352 set_bit(to, mle->maybe_map);
1353 break;
1354 case DLM_MASTER_RESP_ERROR:
1355 mlog(0, "node %u hit an error, resending\n", to);
1356 resend = 1;
1357 response = 0;
1358 break;
1359 default:
1360 mlog(ML_ERROR, "bad response! %u\n", response);
1361 BUG();
1362 }
1363 spin_unlock(&mle->spinlock);
1364 if (resend) {
1365 /* this is also totally crude */
1366 msleep(50);
1367 goto again;
1368 }
1369
1370out:
1371 return ret;
1372}
1373
1374/*
1375 * locks that can be taken here:
1376 * dlm->spinlock
1377 * res->spinlock
1378 * mle->spinlock
1379 * dlm->master_list
1380 *
1381 * if possible, TRIM THIS DOWN!!!
1382 */
1383int dlm_master_request_handler(struct o2net_msg *msg, u32 len, void *data)
1384{
1385 u8 response = DLM_MASTER_RESP_MAYBE;
1386 struct dlm_ctxt *dlm = data;
9c6510a5 1387 struct dlm_lock_resource *res = NULL;
6714d8e8
KH		 1388 struct dlm_master_request *request = (struct dlm_master_request *) msg->buf;
1389 struct dlm_master_list_entry *mle = NULL, *tmpmle = NULL;
1390 char *name;
a3d33291 1391 unsigned int namelen, hash;
6714d8e8
KH		 1392 int found, ret;
1393 int set_maybe;
9c6510a5 1394 int dispatch_assert = 0;
6714d8e8
KH		 1395
1396 if (!dlm_grab(dlm))
1397 return DLM_MASTER_RESP_NO;
1398
1399 if (!dlm_domain_fully_joined(dlm)) {
1400 response = DLM_MASTER_RESP_NO;
1401 goto send_response;
1402 }
1403
1404 name = request->name;
1405 namelen = request->namelen;
a3d33291 1406 hash = dlm_lockid_hash(name, namelen);
6714d8e8
KH		 1407
1408 if (namelen > DLM_LOCKID_NAME_MAX) {
1409 response = DLM_IVBUFLEN;
1410 goto send_response;
1411 }
1412
1413way_up_top:
1414 spin_lock(&dlm->spinlock);
a3d33291 1415 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
6714d8e8
KH		 1416 if (res) {
1417 spin_unlock(&dlm->spinlock);
1418
1419 /* take care of the easy cases up front */
1420 spin_lock(&res->spinlock);
1421 if (res->state & DLM_LOCK_RES_RECOVERING) {
1422 spin_unlock(&res->spinlock);
1423 mlog(0, "returning DLM_MASTER_RESP_ERROR since res is "
1424 "being recovered\n");
1425 response = DLM_MASTER_RESP_ERROR;
1426 if (mle)
1427 kmem_cache_free(dlm_mle_cache, mle);
1428 goto send_response;
1429 }
1430
1431 if (res->owner == dlm->node_num) {
6714d8e8
KH		 1432 spin_unlock(&res->spinlock);
1433 // mlog(0, "this node is the master\n");
1434 response = DLM_MASTER_RESP_YES;
1435 if (mle)
1436 kmem_cache_free(dlm_mle_cache, mle);
1437
1438 /* this node is the owner.
1439 * there is some extra work that needs to
1440 * happen now. the requesting node has
1441 * caused all nodes up to this one to
1442 * create mles. this node now needs to
1443 * go back and clean those up. */
9c6510a5 1444 dispatch_assert = 1;
6714d8e8
KH		 1445 goto send_response;
1446 } else if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1447 spin_unlock(&res->spinlock);
1448 // mlog(0, "node %u is the master\n", res->owner);
1449 response = DLM_MASTER_RESP_NO;
1450 if (mle)
1451 kmem_cache_free(dlm_mle_cache, mle);
1452 goto send_response;
1453 }
1454
1455 /* ok, there is no owner. either this node is
1456 * being blocked, or it is actively trying to
1457 * master this lock. */
1458 if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
1459 mlog(ML_ERROR, "lock with no owner should be "
1460 "in-progress!\n");
1461 BUG();
1462 }
1463
1464 // mlog(0, "lockres is in progress...\n");
1465 spin_lock(&dlm->master_lock);
1466 found = dlm_find_mle(dlm, &tmpmle, name, namelen);
1467 if (!found) {
1468 mlog(ML_ERROR, "no mle found for this lock!\n");
1469 BUG();
1470 }
1471 set_maybe = 1;
1472 spin_lock(&tmpmle->spinlock);
1473 if (tmpmle->type == DLM_MLE_BLOCK) {
1474 // mlog(0, "this node is waiting for "
1475 // "lockres to be mastered\n");
1476 response = DLM_MASTER_RESP_NO;
1477 } else if (tmpmle->type == DLM_MLE_MIGRATION) {
1478 mlog(0, "node %u is master, but trying to migrate to "
1479 "node %u.\n", tmpmle->master, tmpmle->new_master);
1480 if (tmpmle->master == dlm->node_num) {
1481 response = DLM_MASTER_RESP_YES;
1482 mlog(ML_ERROR, "no owner on lockres, but this "
1483 "node is trying to migrate it to %u?!\n",
1484 tmpmle->new_master);
1485 BUG();
1486 } else {
1487 /* the real master can respond on its own */
1488 response = DLM_MASTER_RESP_NO;
1489 }
1490 } else if (tmpmle->master != DLM_LOCK_RES_OWNER_UNKNOWN) {
1491 set_maybe = 0;
9c6510a5 1492 if (tmpmle->master == dlm->node_num) {
6714d8e8 1493 response = DLM_MASTER_RESP_YES;
9c6510a5
KH		 1494 /* this node will be the owner.
1495 * go back and clean the mles on any
1496 * other nodes */
1497 dispatch_assert = 1;
1498 } else
6714d8e8
KH		 1499 response = DLM_MASTER_RESP_NO;
1500 } else {
1501 // mlog(0, "this node is attempting to "
1502 // "master lockres\n");
1503 response = DLM_MASTER_RESP_MAYBE;
1504 }
1505 if (set_maybe)
1506 set_bit(request->node_idx, tmpmle->maybe_map);
1507 spin_unlock(&tmpmle->spinlock);
1508
1509 spin_unlock(&dlm->master_lock);
1510 spin_unlock(&res->spinlock);
1511
1512 /* keep the mle attached to heartbeat events */
1513 dlm_put_mle(tmpmle);
1514 if (mle)
1515 kmem_cache_free(dlm_mle_cache, mle);
1516 goto send_response;
1517 }
1518
1519 /*
1520 * lockres doesn't exist on this node
1521 * if there is an MLE_BLOCK, return NO
1522 * if there is an MLE_MASTER, return MAYBE
1523 * otherwise, add an MLE_BLOCK, return NO
1524 */
1525 spin_lock(&dlm->master_lock);
1526 found = dlm_find_mle(dlm, &tmpmle, name, namelen);
1527 if (!found) {
1528 /* this lockid has never been seen on this node yet */
1529 // mlog(0, "no mle found\n");
1530 if (!mle) {
1531 spin_unlock(&dlm->master_lock);
1532 spin_unlock(&dlm->spinlock);
1533
1534 mle = (struct dlm_master_list_entry *)
ad8100e0 1535 kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
6714d8e8 1536 if (!mle) {
6714d8e8 1537 response = DLM_MASTER_RESP_ERROR;
9c6510a5 1538 mlog_errno(-ENOMEM);
6714d8e8
KH		 1539 goto send_response;
1540 }
6714d8e8
KH		 1541 goto way_up_top;
1542 }
1543
1544 // mlog(0, "this is second time thru, already allocated, "
1545 // "add the block.\n");
41b8c8a1 1546 dlm_init_mle(mle, DLM_MLE_BLOCK, dlm, NULL, name, namelen);
6714d8e8
KH		 1547 set_bit(request->node_idx, mle->maybe_map);
1548 list_add(&mle->list, &dlm->master_list);
1549 response = DLM_MASTER_RESP_NO;
1550 } else {
1551 // mlog(0, "mle was found\n");
1552 set_maybe = 1;
1553 spin_lock(&tmpmle->spinlock);
9c6510a5
KH		 1554 if (tmpmle->master == dlm->node_num) {
1555 mlog(ML_ERROR, "no lockres, but an mle with this node as master!\n");
1556 BUG();
1557 }
6714d8e8
KH		 1558 if (tmpmle->type == DLM_MLE_BLOCK)
1559 response = DLM_MASTER_RESP_NO;
1560 else if (tmpmle->type == DLM_MLE_MIGRATION) {
1561 mlog(0, "migration mle was found (%u->%u)\n",
1562 tmpmle->master, tmpmle->new_master);
6714d8e8
KH		 1563 /* real master can respond on its own */
1564 response = DLM_MASTER_RESP_NO;
9c6510a5
KH		 1565 } else
1566 response = DLM_MASTER_RESP_MAYBE;
6714d8e8
KH		 1567 if (set_maybe)
1568 set_bit(request->node_idx, tmpmle->maybe_map);
1569 spin_unlock(&tmpmle->spinlock);
1570 }
1571 spin_unlock(&dlm->master_lock);
1572 spin_unlock(&dlm->spinlock);
1573
1574 if (found) {
1575 /* keep the mle attached to heartbeat events */
1576 dlm_put_mle(tmpmle);
1577 }
1578send_response:
9c6510a5
KH		 1579
1580 if (dispatch_assert) {
1581 if (response != DLM_MASTER_RESP_YES)
1582 mlog(ML_ERROR, "invalid response %d\n", response);
1583 if (!res) {
1584 mlog(ML_ERROR, "bad lockres while trying to assert!\n");
1585 BUG();
1586 }
1587 mlog(0, "%u is the owner of %.*s, cleaning everyone else\n",
1588 dlm->node_num, res->lockname.len, res->lockname.name);
1589 ret = dlm_dispatch_assert_master(dlm, res, 0, request->node_idx,
1590 DLM_ASSERT_MASTER_MLE_CLEANUP);
1591 if (ret < 0) {
1592 mlog(ML_ERROR, "failed to dispatch assert master work\n");
1593 response = DLM_MASTER_RESP_ERROR;
1594 }
1595 }
1596
6714d8e8
KH		 1597 dlm_put(dlm);
1598 return response;
1599}
1600
1601/*
1602 * DLM_ASSERT_MASTER_MSG
1603 */
1604
1605
1606/*
1607 * NOTE: this can be used for debugging
1608 * can periodically run all locks owned by this node
1609 * and re-assert across the cluster...
1610 */
1611static int dlm_do_assert_master(struct dlm_ctxt *dlm, const char *lockname,
1612 unsigned int namelen, void *nodemap,
1613 u32 flags)
1614{
1615 struct dlm_assert_master assert;
1616 int to, tmpret;
1617 struct dlm_node_iter iter;
1618 int ret = 0;
9c6510a5 1619 int reassert;
6714d8e8
KH		 1620
1621 BUG_ON(namelen > O2NM_MAX_NAME_LEN);
9c6510a5
KH		 1622again:
1623 reassert = 0;
6714d8e8
KH		 1624
1625 /* note that if this nodemap is empty, it returns 0 */
1626 dlm_node_iter_init(nodemap, &iter);
1627 while ((to = dlm_node_iter_next(&iter)) >= 0) {
1628 int r = 0;
a9ee4c8a
KH		 1629 struct dlm_master_list_entry *mle = NULL;
1630
6714d8e8
KH		 1631 mlog(0, "sending assert master to %d (%.*s)\n", to,
1632 namelen, lockname);
1633 memset(&assert, 0, sizeof(assert));
1634 assert.node_idx = dlm->node_num;
1635 assert.namelen = namelen;
1636 memcpy(assert.name, lockname, namelen);
1637 assert.flags = cpu_to_be32(flags);
1638
1639 tmpret = o2net_send_message(DLM_ASSERT_MASTER_MSG, dlm->key,
1640 &assert, sizeof(assert), to, &r);
1641 if (tmpret < 0) {
3b3b84a8 1642 mlog(0, "assert_master returned %d!\n", tmpret);
6714d8e8 1643 if (!dlm_is_host_down(tmpret)) {
3b3b84a8 1644 mlog(ML_ERROR, "unhandled error=%d!\n", tmpret);
6714d8e8
KH		 1645 BUG();
1646 }
1647 /* a node died. finish out the rest of the nodes. */
3b3b84a8 1648 mlog(0, "link to %d went down!\n", to);
6714d8e8
KH		 1649 /* any nonzero status return will do */
1650 ret = tmpret;
1651 } else if (r < 0) {
1652 /* ok, something horribly messed. kill thyself. */
1653 mlog(ML_ERROR,"during assert master of %.*s to %u, "
1654 "got %d.\n", namelen, lockname, to, r);
a9ee4c8a
KH		 1655 spin_lock(&dlm->spinlock);
1656 spin_lock(&dlm->master_lock);
1657 if (dlm_find_mle(dlm, &mle, (char *)lockname,
1658 namelen)) {
1659 dlm_print_one_mle(mle);
1660 __dlm_put_mle(mle);
1661 }
1662 spin_unlock(&dlm->master_lock);
1663 spin_unlock(&dlm->spinlock);
6714d8e8 1664 BUG();
9c6510a5
KH		 1665 } else if (r == EAGAIN) {
1666 mlog(0, "%.*s: node %u create mles on other "
1667 "nodes and requests a re-assert\n",
1668 namelen, lockname, to);
1669 reassert = 1;
6714d8e8
KH		 1670 }
1671 }
1672
9c6510a5
KH		 1673 if (reassert)
1674 goto again;
1675
6714d8e8
KH		 1676 return ret;
1677}
1678
1679/*
1680 * locks that can be taken here:
1681 * dlm->spinlock
1682 * res->spinlock
1683 * mle->spinlock
1684 * dlm->master_list
1685 *
1686 * if possible, TRIM THIS DOWN!!!
1687 */
1688int dlm_assert_master_handler(struct o2net_msg *msg, u32 len, void *data)
1689{
1690 struct dlm_ctxt *dlm = data;
1691 struct dlm_master_list_entry *mle = NULL;
1692 struct dlm_assert_master *assert = (struct dlm_assert_master *)msg->buf;
1693 struct dlm_lock_resource *res = NULL;
1694 char *name;
a3d33291 1695 unsigned int namelen, hash;
6714d8e8 1696 u32 flags;
9c6510a5
KH		 1697 int master_request = 0;
1698 int ret = 0;
6714d8e8
KH		 1699
1700 if (!dlm_grab(dlm))
1701 return 0;
1702
1703 name = assert->name;
1704 namelen = assert->namelen;
a3d33291 1705 hash = dlm_lockid_hash(name, namelen);
6714d8e8
KH		 1706 flags = be32_to_cpu(assert->flags);
1707
1708 if (namelen > DLM_LOCKID_NAME_MAX) {
1709 mlog(ML_ERROR, "Invalid name length!");
1710 goto done;
1711 }
1712
1713 spin_lock(&dlm->spinlock);
1714
1715 if (flags)
1716 mlog(0, "assert_master with flags: %u\n", flags);
1717
1718 /* find the MLE */
1719 spin_lock(&dlm->master_lock);
1720 if (!dlm_find_mle(dlm, &mle, name, namelen)) {
1721 /* not an error, could be master just re-asserting */
1722 mlog(0, "just got an assert_master from %u, but no "
1723 "MLE for it! (%.*s)\n", assert->node_idx,
1724 namelen, name);
1725 } else {
1726 int bit = find_next_bit (mle->maybe_map, O2NM_MAX_NODES, 0);
1727 if (bit >= O2NM_MAX_NODES) {
1728 /* not necessarily an error, though less likely.
1729 * could be master just re-asserting. */
aa852354 1730 mlog(0, "no bits set in the maybe_map, but %u "
6714d8e8
KH		 1731 "is asserting! (%.*s)\n", assert->node_idx,
1732 namelen, name);
1733 } else if (bit != assert->node_idx) {
1734 if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
1735 mlog(0, "master %u was found, %u should "
1736 "back off\n", assert->node_idx, bit);
1737 } else {
1738 /* with the fix for bug 569, a higher node
1739 * number winning the mastery will respond
1740 * YES to mastery requests, but this node
1741 * had no way of knowing. let it pass. */
aa852354 1742 mlog(0, "%u is the lowest node, "
6714d8e8
KH		 1743 "%u is asserting. (%.*s) %u must "
1744 "have begun after %u won.\n", bit,
1745 assert->node_idx, namelen, name, bit,
1746 assert->node_idx);
1747 }
1748 }
2d1a868c
KH		 1749 if (mle->type == DLM_MLE_MIGRATION) {
1750 if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
1751 mlog(0, "%s:%.*s: got cleanup assert"
1752 " from %u for migration\n",
1753 dlm->name, namelen, name,
1754 assert->node_idx);
1755 } else if (!(flags & DLM_ASSERT_MASTER_FINISH_MIGRATION)) {
1756 mlog(0, "%s:%.*s: got unrelated assert"
1757 " from %u for migration, ignoring\n",
1758 dlm->name, namelen, name,
1759 assert->node_idx);
1760 __dlm_put_mle(mle);
1761 spin_unlock(&dlm->master_lock);
1762 spin_unlock(&dlm->spinlock);
1763 goto done;
1764 }
1765 }
6714d8e8
KH		 1766 }
1767 spin_unlock(&dlm->master_lock);
1768
1769 /* ok everything checks out with the MLE
1770 * now check to see if there is a lockres */
a3d33291 1771 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
6714d8e8
KH		 1772 if (res) {
1773 spin_lock(&res->spinlock);
1774 if (res->state & DLM_LOCK_RES_RECOVERING) {
1775 mlog(ML_ERROR, "%u asserting but %.*s is "
1776 "RECOVERING!\n", assert->node_idx, namelen, name);
1777 goto kill;
1778 }
1779 if (!mle) {
dc2ed195
KH		 1780 if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN &&
1781 res->owner != assert->node_idx) {
6714d8e8
KH		 1782 mlog(ML_ERROR, "assert_master from "
1783 "%u, but current owner is "
1784 "%u! (%.*s)\n",
1785 assert->node_idx, res->owner,
1786 namelen, name);
1787 goto kill;
1788 }
1789 } else if (mle->type != DLM_MLE_MIGRATION) {
1790 if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1791 /* owner is just re-asserting */
1792 if (res->owner == assert->node_idx) {
1793 mlog(0, "owner %u re-asserting on "
1794 "lock %.*s\n", assert->node_idx,
1795 namelen, name);
1796 goto ok;
1797 }
1798 mlog(ML_ERROR, "got assert_master from "
1799 "node %u, but %u is the owner! "
1800 "(%.*s)\n", assert->node_idx,
1801 res->owner, namelen, name);
1802 goto kill;
1803 }
1804 if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
1805 mlog(ML_ERROR, "got assert from %u, but lock "
1806 "with no owner should be "
1807 "in-progress! (%.*s)\n",
1808 assert->node_idx,
1809 namelen, name);
1810 goto kill;
1811 }
1812 } else /* mle->type == DLM_MLE_MIGRATION */ {
1813 /* should only be getting an assert from new master */
1814 if (assert->node_idx != mle->new_master) {
1815 mlog(ML_ERROR, "got assert from %u, but "
1816 "new master is %u, and old master "
1817 "was %u (%.*s)\n",
1818 assert->node_idx, mle->new_master,
1819 mle->master, namelen, name);
1820 goto kill;
1821 }
1822
1823 }
1824ok:
1825 spin_unlock(&res->spinlock);
1826 }
1827 spin_unlock(&dlm->spinlock);
1828
1829 // mlog(0, "woo! got an assert_master from node %u!\n",
1830 // assert->node_idx);
1831 if (mle) {
9c6510a5
KH		 1832 int extra_ref = 0;
1833 int nn = -1;
a2bf0477 1834 int rr, err = 0;
6714d8e8
KH		 1835
1836 spin_lock(&mle->spinlock);
9c6510a5
KH		 1837 if (mle->type == DLM_MLE_BLOCK || mle->type == DLM_MLE_MIGRATION)
1838 extra_ref = 1;
1839 else {
1840 /* MASTER mle: if any bits set in the response map
1841 * then the calling node needs to re-assert to clear
1842 * up nodes that this node contacted */
1843 while ((nn = find_next_bit (mle->response_map, O2NM_MAX_NODES,
1844 nn+1)) < O2NM_MAX_NODES) {
1845 if (nn != dlm->node_num && nn != assert->node_idx)
1846 master_request = 1;
1847 }
1848 }
6714d8e8
KH		 1849 mle->master = assert->node_idx;
1850 atomic_set(&mle->woken, 1);
1851 wake_up(&mle->wq);
1852 spin_unlock(&mle->spinlock);
1853
a2bf0477 1854 if (res) {
6714d8e8 1855 spin_lock(&res->spinlock);
a2bf0477
KH		 1856 if (mle->type == DLM_MLE_MIGRATION) {
1857 mlog(0, "finishing off migration of lockres %.*s, "
1858 "from %u to %u\n",
1859 res->lockname.len, res->lockname.name,
1860 dlm->node_num, mle->new_master);
1861 res->state &= ~DLM_LOCK_RES_MIGRATING;
1862 dlm_change_lockres_owner(dlm, res, mle->new_master);
1863 BUG_ON(res->state & DLM_LOCK_RES_DIRTY);
1864 } else {
1865 dlm_change_lockres_owner(dlm, res, mle->master);
1866 }
6714d8e8
KH		 1867 spin_unlock(&res->spinlock);
1868 }
a2bf0477
KH		 1869
1870 /* master is known, detach if not already detached.
1871 * ensures that only one assert_master call will happen
1872 * on this mle. */
1873 spin_lock(&dlm->spinlock);
1874 spin_lock(&dlm->master_lock);
1875
1876 rr = atomic_read(&mle->mle_refs.refcount);
1877 if (mle->inuse > 0) {
1878 if (extra_ref && rr < 3)
1879 err = 1;
1880 else if (!extra_ref && rr < 2)
1881 err = 1;
1882 } else {
1883 if (extra_ref && rr < 2)
1884 err = 1;
1885 else if (!extra_ref && rr < 1)
1886 err = 1;
1887 }
1888 if (err) {
1889 mlog(ML_ERROR, "%s:%.*s: got assert master from %u "
1890 "that will mess up this node, refs=%d, extra=%d, "
1891 "inuse=%d\n", dlm->name, namelen, name,
1892 assert->node_idx, rr, extra_ref, mle->inuse);
1893 dlm_print_one_mle(mle);
1894 }
1895 list_del_init(&mle->list);
1896 __dlm_mle_detach_hb_events(dlm, mle);
1897 __dlm_put_mle(mle);
6714d8e8
KH		 1898 if (extra_ref) {
1899 /* the assert master message now balances the extra
1900 * ref given by the master / migration request message.
1901 * if this is the last put, it will be removed
1902 * from the list. */
a2bf0477
KH		 1903 __dlm_put_mle(mle);
1904 }
1905 spin_unlock(&dlm->master_lock);
1906 spin_unlock(&dlm->spinlock);
1907 } else if (res) {
1908 if (res->owner != assert->node_idx) {
1909 mlog(0, "assert_master from %u, but current "
1910 "owner is %u (%.*s), no mle\n", assert->node_idx,
1911 res->owner, namelen, name);
6714d8e8
KH		 1912 }
1913 }
1914
1915done:
9c6510a5 1916 ret = 0;
6714d8e8
KH		 1917 if (res)
1918 dlm_lockres_put(res);
1919 dlm_put(dlm);
9c6510a5
KH		 1920 if (master_request) {
1921 mlog(0, "need to tell master to reassert\n");
1922 ret = EAGAIN; // positive. negative would shoot down the node.
1923 }
1924 return ret;
6714d8e8
KH		 1925
1926kill:
1927 /* kill the caller! */
a9ee4c8a
KH		 1928 mlog(ML_ERROR, "Bad message received from another node. Dumping state "
1929 "and killing the other node now! This node is OK and can continue.\n");
1930 __dlm_print_one_lock_resource(res);
6714d8e8
KH		 1931 spin_unlock(&res->spinlock);
1932 spin_unlock(&dlm->spinlock);
1933 dlm_lockres_put(res);
6714d8e8
KH		 1934 dlm_put(dlm);
1935 return -EINVAL;
1936}
1937
1938int dlm_dispatch_assert_master(struct dlm_ctxt *dlm,
1939 struct dlm_lock_resource *res,
1940 int ignore_higher, u8 request_from, u32 flags)
1941{
1942 struct dlm_work_item *item;
ad8100e0 1943 item = kcalloc(1, sizeof(*item), GFP_NOFS);
6714d8e8
KH		 1944 if (!item)
1945 return -ENOMEM;
1946
1947
1948 /* queue up work for dlm_assert_master_worker */
1949 dlm_grab(dlm); /* get an extra ref for the work item */
1950 dlm_init_work_item(dlm, item, dlm_assert_master_worker, NULL);
1951 item->u.am.lockres = res; /* already have a ref */
1952 /* can optionally ignore node numbers higher than this node */
1953 item->u.am.ignore_higher = ignore_higher;
1954 item->u.am.request_from = request_from;
1955 item->u.am.flags = flags;
1956
9c6510a5
KH		 1957 if (ignore_higher)
1958 mlog(0, "IGNORE HIGHER: %.*s\n", res->lockname.len,
1959 res->lockname.name);
1960
6714d8e8
KH		 1961 spin_lock(&dlm->work_lock);
1962 list_add_tail(&item->list, &dlm->work_list);
1963 spin_unlock(&dlm->work_lock);
1964
1965 schedule_work(&dlm->dispatched_work);
1966 return 0;
1967}
1968
1969static void dlm_assert_master_worker(struct dlm_work_item *item, void *data)
1970{
1971 struct dlm_ctxt *dlm = data;
1972 int ret = 0;
1973 struct dlm_lock_resource *res;
1974 unsigned long nodemap[BITS_TO_LONGS(O2NM_MAX_NODES)];
1975 int ignore_higher;
1976 int bit;
1977 u8 request_from;
1978 u32 flags;
1979
1980 dlm = item->dlm;
1981 res = item->u.am.lockres;
1982 ignore_higher = item->u.am.ignore_higher;
1983 request_from = item->u.am.request_from;
1984 flags = item->u.am.flags;
1985
1986 spin_lock(&dlm->spinlock);
1987 memcpy(nodemap, dlm->domain_map, sizeof(nodemap));
1988 spin_unlock(&dlm->spinlock);
1989
1990 clear_bit(dlm->node_num, nodemap);
1991 if (ignore_higher) {
1992 /* if is this just to clear up mles for nodes below
1993 * this node, do not send the message to the original
1994 * caller or any node number higher than this */
1995 clear_bit(request_from, nodemap);
1996 bit = dlm->node_num;
1997 while (1) {
1998 bit = find_next_bit(nodemap, O2NM_MAX_NODES,
1999 bit+1);
2000 if (bit >= O2NM_MAX_NODES)
2001 break;
2002 clear_bit(bit, nodemap);
2003 }
2004 }
2005
36407488
KH		 2006 /*
2007 * If we're migrating this lock to someone else, we are no
2008 * longer allowed to assert out own mastery. OTOH, we need to
2009 * prevent migration from starting while we're still asserting
2010 * our dominance. The reserved ast delays migration.
2011 */
2012 spin_lock(&res->spinlock);
2013 if (res->state & DLM_LOCK_RES_MIGRATING) {
2014 mlog(0, "Someone asked us to assert mastery, but we're "
2015 "in the middle of migration. Skipping assert, "
2016 "the new master will handle that.\n");
2017 spin_unlock(&res->spinlock);
2018 goto put;
2019 } else
2020 __dlm_lockres_reserve_ast(res);
2021 spin_unlock(&res->spinlock);
2022
6714d8e8
KH		 2023 /* this call now finishes out the nodemap
2024 * even if one or more nodes die */
2025 mlog(0, "worker about to master %.*s here, this=%u\n",
2026 res->lockname.len, res->lockname.name, dlm->node_num);
2027 ret = dlm_do_assert_master(dlm, res->lockname.name,
2028 res->lockname.len,
2029 nodemap, flags);
2030 if (ret < 0) {
2031 /* no need to restart, we are done */
3b3b84a8
KH		 2032 if (!dlm_is_host_down(ret))
2033 mlog_errno(ret);
6714d8e8
KH		 2034 }
2035
36407488
KH		 2036 /* Ok, we've asserted ourselves. Let's let migration start. */
2037 dlm_lockres_release_ast(dlm, res);
2038
2039put:
6714d8e8
KH		 2040 dlm_lockres_put(res);
2041
2042 mlog(0, "finished with dlm_assert_master_worker\n");
2043}
2044
c03872f5
KH		 2045/* SPECIAL CASE for the $RECOVERY lock used by the recovery thread.
2046 * We cannot wait for node recovery to complete to begin mastering this
2047 * lockres because this lockres is used to kick off recovery! ;-)
2048 * So, do a pre-check on all living nodes to see if any of those nodes
2049 * think that $RECOVERY is currently mastered by a dead node. If so,
2050 * we wait a short time to allow that node to get notified by its own
2051 * heartbeat stack, then check again. All $RECOVERY lock resources
2052 * mastered by dead nodes are purged when the hearbeat callback is
2053 * fired, so we can know for sure that it is safe to continue once
2054 * the node returns a live node or no node. */
2055static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
2056 struct dlm_lock_resource *res)
2057{
2058 struct dlm_node_iter iter;
2059 int nodenum;
2060 int ret = 0;
2061 u8 master = DLM_LOCK_RES_OWNER_UNKNOWN;
2062
2063 spin_lock(&dlm->spinlock);
2064 dlm_node_iter_init(dlm->domain_map, &iter);
2065 spin_unlock(&dlm->spinlock);
2066
2067 while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
2068 /* do not send to self */
2069 if (nodenum == dlm->node_num)
2070 continue;
2071 ret = dlm_do_master_requery(dlm, res, nodenum, &master);
2072 if (ret < 0) {
2073 mlog_errno(ret);
2074 if (!dlm_is_host_down(ret))
2075 BUG();
2076 /* host is down, so answer for that node would be
2077 * DLM_LOCK_RES_OWNER_UNKNOWN. continue. */
f42a100b 2078 ret = 0;
c03872f5
KH		 2079 }
2080
2081 if (master != DLM_LOCK_RES_OWNER_UNKNOWN) {
2082 /* check to see if this master is in the recovery map */
2083 spin_lock(&dlm->spinlock);
2084 if (test_bit(master, dlm->recovery_map)) {
2085 mlog(ML_NOTICE, "%s: node %u has not seen "
2086 "node %u go down yet, and thinks the "
2087 "dead node is mastering the recovery "
2088 "lock. must wait.\n", dlm->name,
2089 nodenum, master);
2090 ret = -EAGAIN;
2091 }
2092 spin_unlock(&dlm->spinlock);
2093 mlog(0, "%s: reco lock master is %u\n", dlm->name,
2094 master);
2095 break;
2096 }
2097 }
2098 return ret;
2099}
2100
6714d8e8
KH		 2101
2102/*
2103 * DLM_MIGRATE_LOCKRES
2104 */
2105
2106
2107int dlm_migrate_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
2108 u8 target)
2109{
2110 struct dlm_master_list_entry *mle = NULL;
2111 struct dlm_master_list_entry *oldmle = NULL;
2112 struct dlm_migratable_lockres *mres = NULL;
2113 int ret = -EINVAL;
2114 const char *name;
2115 unsigned int namelen;
2116 int mle_added = 0;
2117 struct list_head *queue, *iter;
2118 int i;
2119 struct dlm_lock *lock;
2120 int empty = 1;
2121
2122 if (!dlm_grab(dlm))
2123 return -EINVAL;
2124
2125 name = res->lockname.name;
2126 namelen = res->lockname.len;
2127
2128 mlog(0, "migrating %.*s to %u\n", namelen, name, target);
2129
2130 /*
2131 * ensure this lockres is a proper candidate for migration
2132 */
2133 spin_lock(&res->spinlock);
2134 if (res->owner == DLM_LOCK_RES_OWNER_UNKNOWN) {
2135 mlog(0, "cannot migrate lockres with unknown owner!\n");
2136 spin_unlock(&res->spinlock);
2137 goto leave;
2138 }
2139 if (res->owner != dlm->node_num) {
2140 mlog(0, "cannot migrate lockres this node doesn't own!\n");
2141 spin_unlock(&res->spinlock);
2142 goto leave;
2143 }
2144 mlog(0, "checking queues...\n");
2145 queue = &res->granted;
2146 for (i=0; i<3; i++) {
2147 list_for_each(iter, queue) {
2148 lock = list_entry (iter, struct dlm_lock, list);
2149 empty = 0;
2150 if (lock->ml.node == dlm->node_num) {
2151 mlog(0, "found a lock owned by this node "
2152 "still on the %s queue! will not "
2153 "migrate this lockres\n",
2154 i==0 ? "granted" :
2155 (i==1 ? "converting" : "blocked"));
2156 spin_unlock(&res->spinlock);
2157 ret = -ENOTEMPTY;
2158 goto leave;
2159 }
2160 }
2161 queue++;
2162 }
2163 mlog(0, "all locks on this lockres are nonlocal. continuing\n");
2164 spin_unlock(&res->spinlock);
2165
2166 /* no work to do */
2167 if (empty) {
2168 mlog(0, "no locks were found on this lockres! done!\n");
2169 ret = 0;
2170 goto leave;
2171 }
2172
2173 /*
2174 * preallocate up front
2175 * if this fails, abort
2176 */
2177
2178 ret = -ENOMEM;
ad8100e0 2179 mres = (struct dlm_migratable_lockres *) __get_free_page(GFP_NOFS);
6714d8e8
KH		 2180 if (!mres) {
2181 mlog_errno(ret);
2182 goto leave;
2183 }
2184
2185 mle = (struct dlm_master_list_entry *) kmem_cache_alloc(dlm_mle_cache,
ad8100e0 2186 GFP_NOFS);
6714d8e8
KH		 2187 if (!mle) {
2188 mlog_errno(ret);
2189 goto leave;
2190 }
2191 ret = 0;
2192
2193 /*
2194 * find a node to migrate the lockres to
2195 */
2196
2197 mlog(0, "picking a migration node\n");
2198 spin_lock(&dlm->spinlock);
2199 /* pick a new node */
2200 if (!test_bit(target, dlm->domain_map) ||
2201 target >= O2NM_MAX_NODES) {
2202 target = dlm_pick_migration_target(dlm, res);
2203 }
2204 mlog(0, "node %u chosen for migration\n", target);
2205
2206 if (target >= O2NM_MAX_NODES ||
2207 !test_bit(target, dlm->domain_map)) {
2208 /* target chosen is not alive */
2209 ret = -EINVAL;
2210 }
2211
2212 if (ret) {
2213 spin_unlock(&dlm->spinlock);
2214 goto fail;
2215 }
2216
2217 mlog(0, "continuing with target = %u\n", target);
2218
2219 /*
2220 * clear any existing master requests and
2221 * add the migration mle to the list
2222 */
2223 spin_lock(&dlm->master_lock);
2224 ret = dlm_add_migration_mle(dlm, res, mle, &oldmle, name,
2225 namelen, target, dlm->node_num);
2226 spin_unlock(&dlm->master_lock);
2227 spin_unlock(&dlm->spinlock);
2228
2229 if (ret == -EEXIST) {
2230 mlog(0, "another process is already migrating it\n");
2231 goto fail;
2232 }
2233 mle_added = 1;
2234
2235 /*
2236 * set the MIGRATING flag and flush asts
2237 * if we fail after this we need to re-dirty the lockres
2238 */
2239 if (dlm_mark_lockres_migrating(dlm, res, target) < 0) {
2240 mlog(ML_ERROR, "tried to migrate %.*s to %u, but "
2241 "the target went down.\n", res->lockname.len,
2242 res->lockname.name, target);
2243 spin_lock(&res->spinlock);
2244 res->state &= ~DLM_LOCK_RES_MIGRATING;
2245 spin_unlock(&res->spinlock);
2246 ret = -EINVAL;
2247 }
2248
2249fail:
2250 if (oldmle) {
2251 /* master is known, detach if not already detached */
2252 dlm_mle_detach_hb_events(dlm, oldmle);
2253 dlm_put_mle(oldmle);
2254 }
2255
2256 if (ret < 0) {
2257 if (mle_added) {
2258 dlm_mle_detach_hb_events(dlm, mle);
2259 dlm_put_mle(mle);
2260 } else if (mle) {
2261 kmem_cache_free(dlm_mle_cache, mle);
2262 }
2263 goto leave;
2264 }
2265
2266 /*
2267 * at this point, we have a migration target, an mle
2268 * in the master list, and the MIGRATING flag set on
2269 * the lockres
2270 */
2271
2272
2273 /* get an extra reference on the mle.
2274 * otherwise the assert_master from the new
2275 * master will destroy this.
2276 * also, make sure that all callers of dlm_get_mle
2277 * take both dlm->spinlock and dlm->master_lock */
2278 spin_lock(&dlm->spinlock);
2279 spin_lock(&dlm->master_lock);
a2bf0477 2280 dlm_get_mle_inuse(mle);
6714d8e8
KH		 2281 spin_unlock(&dlm->master_lock);
2282 spin_unlock(&dlm->spinlock);
2283
2284 /* notify new node and send all lock state */
2285 /* call send_one_lockres with migration flag.
2286 * this serves as notice to the target node that a
2287 * migration is starting. */
2288 ret = dlm_send_one_lockres(dlm, res, mres, target,
2289 DLM_MRES_MIGRATION);
2290
2291 if (ret < 0) {
2292 mlog(0, "migration to node %u failed with %d\n",
2293 target, ret);
2294 /* migration failed, detach and clean up mle */
2295 dlm_mle_detach_hb_events(dlm, mle);
2296 dlm_put_mle(mle);
a2bf0477
KH		 2297 dlm_put_mle_inuse(mle);
2298 spin_lock(&res->spinlock);
2299 res->state &= ~DLM_LOCK_RES_MIGRATING;
2300 spin_unlock(&res->spinlock);
6714d8e8
KH		 2301 goto leave;
2302 }
2303
2304 /* at this point, the target sends a message to all nodes,
2305 * (using dlm_do_migrate_request). this node is skipped since
2306 * we had to put an mle in the list to begin the process. this
2307 * node now waits for target to do an assert master. this node
2308 * will be the last one notified, ensuring that the migration
2309 * is complete everywhere. if the target dies while this is
2310 * going on, some nodes could potentially see the target as the
2311 * master, so it is important that my recovery finds the migration
2312 * mle and sets the master to UNKNONWN. */
2313
2314
2315 /* wait for new node to assert master */
2316 while (1) {
2317 ret = wait_event_interruptible_timeout(mle->wq,
2318 (atomic_read(&mle->woken) == 1),
2319 msecs_to_jiffies(5000));
2320
2321 if (ret >= 0) {
2322 if (atomic_read(&mle->woken) == 1 ||
2323 res->owner == target)
2324 break;
2325
2326 mlog(0, "timed out during migration\n");
e2faea4c
KH		 2327 /* avoid hang during shutdown when migrating lockres
2328 * to a node which also goes down */
2329 if (dlm_is_node_dead(dlm, target)) {
aa852354
KH		 2330 mlog(0, "%s:%.*s: expected migration "
2331 "target %u is no longer up, restarting\n",
e2faea4c
KH		 2332 dlm->name, res->lockname.len,
2333 res->lockname.name, target);
2334 ret = -ERESTARTSYS;
2335 }
6714d8e8
KH		 2336 }
2337 if (ret == -ERESTARTSYS) {
2338 /* migration failed, detach and clean up mle */
2339 dlm_mle_detach_hb_events(dlm, mle);
2340 dlm_put_mle(mle);
a2bf0477
KH		 2341 dlm_put_mle_inuse(mle);
2342 spin_lock(&res->spinlock);
2343 res->state &= ~DLM_LOCK_RES_MIGRATING;
2344 spin_unlock(&res->spinlock);
6714d8e8
KH		 2345 goto leave;
2346 }
2347 /* TODO: if node died: stop, clean up, return error */
2348 }
2349
2350 /* all done, set the owner, clear the flag */
2351 spin_lock(&res->spinlock);
2352 dlm_set_lockres_owner(dlm, res, target);
2353 res->state &= ~DLM_LOCK_RES_MIGRATING;
2354 dlm_remove_nonlocal_locks(dlm, res);
2355 spin_unlock(&res->spinlock);
2356 wake_up(&res->wq);
2357
2358 /* master is known, detach if not already detached */
2359 dlm_mle_detach_hb_events(dlm, mle);
a2bf0477 2360 dlm_put_mle_inuse(mle);
6714d8e8
KH		 2361 ret = 0;
2362
2363 dlm_lockres_calc_usage(dlm, res);
2364
2365leave:
2366 /* re-dirty the lockres if we failed */
2367 if (ret < 0)
2368 dlm_kick_thread(dlm, res);
2369
2370 /* TODO: cleanup */
2371 if (mres)
2372 free_page((unsigned long)mres);
2373
2374 dlm_put(dlm);
2375
2376 mlog(0, "returning %d\n", ret);
2377 return ret;
2378}
2379EXPORT_SYMBOL_GPL(dlm_migrate_lockres);
2380
2381int dlm_lock_basts_flushed(struct dlm_ctxt *dlm, struct dlm_lock *lock)
2382{
2383 int ret;
2384 spin_lock(&dlm->ast_lock);
2385 spin_lock(&lock->spinlock);
2386 ret = (list_empty(&lock->bast_list) && !lock->bast_pending);
2387 spin_unlock(&lock->spinlock);
2388 spin_unlock(&dlm->ast_lock);
2389 return ret;
2390}
2391
2392static int dlm_migration_can_proceed(struct dlm_ctxt *dlm,
2393 struct dlm_lock_resource *res,
2394 u8 mig_target)
2395{
2396 int can_proceed;
2397 spin_lock(&res->spinlock);
2398 can_proceed = !!(res->state & DLM_LOCK_RES_MIGRATING);
2399 spin_unlock(&res->spinlock);
2400
2401 /* target has died, so make the caller break out of the
2402 * wait_event, but caller must recheck the domain_map */
2403 spin_lock(&dlm->spinlock);
2404 if (!test_bit(mig_target, dlm->domain_map))
2405 can_proceed = 1;
2406 spin_unlock(&dlm->spinlock);
2407 return can_proceed;
2408}
2409
2410int dlm_lockres_is_dirty(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
2411{
2412 int ret;
2413 spin_lock(&res->spinlock);
2414 ret = !!(res->state & DLM_LOCK_RES_DIRTY);
2415 spin_unlock(&res->spinlock);
2416 return ret;
2417}
2418
2419
2420static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
2421 struct dlm_lock_resource *res,
2422 u8 target)
2423{
2424 int ret = 0;
2425
2426 mlog(0, "dlm_mark_lockres_migrating: %.*s, from %u to %u\n",
2427 res->lockname.len, res->lockname.name, dlm->node_num,
2428 target);
2429 /* need to set MIGRATING flag on lockres. this is done by
2430 * ensuring that all asts have been flushed for this lockres. */
2431 spin_lock(&res->spinlock);
2432 BUG_ON(res->migration_pending);
2433 res->migration_pending = 1;
2434 /* strategy is to reserve an extra ast then release
2435 * it below, letting the release do all of the work */
2436 __dlm_lockres_reserve_ast(res);
2437 spin_unlock(&res->spinlock);
2438
2439 /* now flush all the pending asts.. hang out for a bit */
2440 dlm_kick_thread(dlm, res);
2441 wait_event(dlm->ast_wq, !dlm_lockres_is_dirty(dlm, res));
2442 dlm_lockres_release_ast(dlm, res);
2443
2444 mlog(0, "about to wait on migration_wq, dirty=%s\n",
2445 res->state & DLM_LOCK_RES_DIRTY ? "yes" : "no");
2446 /* if the extra ref we just put was the final one, this
2447 * will pass thru immediately. otherwise, we need to wait
2448 * for the last ast to finish. */
2449again:
2450 ret = wait_event_interruptible_timeout(dlm->migration_wq,
2451 dlm_migration_can_proceed(dlm, res, target),
2452 msecs_to_jiffies(1000));
2453 if (ret < 0) {
2454 mlog(0, "woken again: migrating? %s, dead? %s\n",
2455 res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
2456 test_bit(target, dlm->domain_map) ? "no":"yes");
2457 } else {
2458 mlog(0, "all is well: migrating? %s, dead? %s\n",
2459 res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
2460 test_bit(target, dlm->domain_map) ? "no":"yes");
2461 }
2462 if (!dlm_migration_can_proceed(dlm, res, target)) {
2463 mlog(0, "trying again...\n");
2464 goto again;
2465 }
2466
2467 /* did the target go down or die? */
2468 spin_lock(&dlm->spinlock);
2469 if (!test_bit(target, dlm->domain_map)) {
2470 mlog(ML_ERROR, "aha. migration target %u just went down\n",
2471 target);
2472 ret = -EHOSTDOWN;
2473 }
2474 spin_unlock(&dlm->spinlock);
2475
2476 /*
2477 * at this point:
2478 *
2479 * o the DLM_LOCK_RES_MIGRATING flag is set
2480 * o there are no pending asts on this lockres
2481 * o all processes trying to reserve an ast on this
2482 * lockres must wait for the MIGRATING flag to clear
2483 */
2484 return ret;
2485}
2486
2487/* last step in the migration process.
2488 * original master calls this to free all of the dlm_lock
2489 * structures that used to be for other nodes. */
2490static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
2491 struct dlm_lock_resource *res)
2492{
2493 struct list_head *iter, *iter2;
2494 struct list_head *queue = &res->granted;
2495 int i;
2496 struct dlm_lock *lock;
2497
2498 assert_spin_locked(&res->spinlock);
2499
2500 BUG_ON(res->owner == dlm->node_num);
2501
2502 for (i=0; i<3; i++) {
2503 list_for_each_safe(iter, iter2, queue) {
2504 lock = list_entry (iter, struct dlm_lock, list);
2505 if (lock->ml.node != dlm->node_num) {
2506 mlog(0, "putting lock for node %u\n",
2507 lock->ml.node);
2508 /* be extra careful */
2509 BUG_ON(!list_empty(&lock->ast_list));
2510 BUG_ON(!list_empty(&lock->bast_list));
2511 BUG_ON(lock->ast_pending);
2512 BUG_ON(lock->bast_pending);
2513 list_del_init(&lock->list);
2514 dlm_lock_put(lock);
2515 }
2516 }
2517 queue++;
2518 }
2519}
2520
2521/* for now this is not too intelligent. we will
2522 * need stats to make this do the right thing.
2523 * this just finds the first lock on one of the
2524 * queues and uses that node as the target. */
2525static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
2526 struct dlm_lock_resource *res)
2527{
2528 int i;
2529 struct list_head *queue = &res->granted;
2530 struct list_head *iter;
2531 struct dlm_lock *lock;
2532 int nodenum;
2533
2534 assert_spin_locked(&dlm->spinlock);
2535
2536 spin_lock(&res->spinlock);
2537 for (i=0; i<3; i++) {
2538 list_for_each(iter, queue) {
2539 /* up to the caller to make sure this node
2540 * is alive */
2541 lock = list_entry (iter, struct dlm_lock, list);
2542 if (lock->ml.node != dlm->node_num) {
2543 spin_unlock(&res->spinlock);
2544 return lock->ml.node;
2545 }
2546 }
2547 queue++;
2548 }
2549 spin_unlock(&res->spinlock);
2550 mlog(0, "have not found a suitable target yet! checking domain map\n");
2551
2552 /* ok now we're getting desperate. pick anyone alive. */
2553 nodenum = -1;
2554 while (1) {
2555 nodenum = find_next_bit(dlm->domain_map,
2556 O2NM_MAX_NODES, nodenum+1);
2557 mlog(0, "found %d in domain map\n", nodenum);
2558 if (nodenum >= O2NM_MAX_NODES)
2559 break;
2560 if (nodenum != dlm->node_num) {
2561 mlog(0, "picking %d\n", nodenum);
2562 return nodenum;
2563 }
2564 }
2565
2566 mlog(0, "giving up. no master to migrate to\n");
2567 return DLM_LOCK_RES_OWNER_UNKNOWN;
2568}
2569
2570
2571
2572/* this is called by the new master once all lockres
2573 * data has been received */
2574static int dlm_do_migrate_request(struct dlm_ctxt *dlm,
2575 struct dlm_lock_resource *res,
2576 u8 master, u8 new_master,
2577 struct dlm_node_iter *iter)
2578{
2579 struct dlm_migrate_request migrate;
2580 int ret, status = 0;
2581 int nodenum;
2582
2583 memset(&migrate, 0, sizeof(migrate));
2584 migrate.namelen = res->lockname.len;
2585 memcpy(migrate.name, res->lockname.name, migrate.namelen);
2586 migrate.new_master = new_master;
2587 migrate.master = master;
2588
2589 ret = 0;
2590
2591 /* send message to all nodes, except the master and myself */
2592 while ((nodenum = dlm_node_iter_next(iter)) >= 0) {
2593 if (nodenum == master ||
2594 nodenum == new_master)
2595 continue;
2596
2597 ret = o2net_send_message(DLM_MIGRATE_REQUEST_MSG, dlm->key,
2598 &migrate, sizeof(migrate), nodenum,
2599 &status);
2600 if (ret < 0)
2601 mlog_errno(ret);
2602 else if (status < 0) {
2603 mlog(0, "migrate request (node %u) returned %d!\n",
2604 nodenum, status);
2605 ret = status;
2606 }
2607 }
2608
2609 if (ret < 0)
2610 mlog_errno(ret);
2611
2612 mlog(0, "returning ret=%d\n", ret);
2613 return ret;
2614}
2615
2616
2617/* if there is an existing mle for this lockres, we now know who the master is.
2618 * (the one who sent us *this* message) we can clear it up right away.
2619 * since the process that put the mle on the list still has a reference to it,
2620 * we can unhash it now, set the master and wake the process. as a result,
2621 * we will have no mle in the list to start with. now we can add an mle for
2622 * the migration and this should be the only one found for those scanning the
2623 * list. */
2624int dlm_migrate_request_handler(struct o2net_msg *msg, u32 len, void *data)
2625{
2626 struct dlm_ctxt *dlm = data;
2627 struct dlm_lock_resource *res = NULL;
2628 struct dlm_migrate_request *migrate = (struct dlm_migrate_request *) msg->buf;
2629 struct dlm_master_list_entry *mle = NULL, *oldmle = NULL;
2630 const char *name;
a3d33291 2631 unsigned int namelen, hash;
6714d8e8
KH		 2632 int ret = 0;
2633
2634 if (!dlm_grab(dlm))
2635 return -EINVAL;
2636
2637 name = migrate->name;
2638 namelen = migrate->namelen;
a3d33291 2639 hash = dlm_lockid_hash(name, namelen);
6714d8e8
KH		 2640
2641 /* preallocate.. if this fails, abort */
2642 mle = (struct dlm_master_list_entry *) kmem_cache_alloc(dlm_mle_cache,
ad8100e0 2643 GFP_NOFS);
6714d8e8
KH		 2644
2645 if (!mle) {
2646 ret = -ENOMEM;
2647 goto leave;
2648 }
2649
2650 /* check for pre-existing lock */
2651 spin_lock(&dlm->spinlock);
a3d33291 2652 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
6714d8e8
KH		 2653 spin_lock(&dlm->master_lock);
2654
2655 if (res) {
2656 spin_lock(&res->spinlock);
2657 if (res->state & DLM_LOCK_RES_RECOVERING) {
2658 /* if all is working ok, this can only mean that we got
2659 * a migrate request from a node that we now see as
2660 * dead. what can we do here? drop it to the floor? */
2661 spin_unlock(&res->spinlock);
2662 mlog(ML_ERROR, "Got a migrate request, but the "
2663 "lockres is marked as recovering!");
2664 kmem_cache_free(dlm_mle_cache, mle);
2665 ret = -EINVAL; /* need a better solution */
2666 goto unlock;
2667 }
2668 res->state |= DLM_LOCK_RES_MIGRATING;
2669 spin_unlock(&res->spinlock);
2670 }
2671
2672 /* ignore status. only nonzero status would BUG. */
2673 ret = dlm_add_migration_mle(dlm, res, mle, &oldmle,
2674 name, namelen,
2675 migrate->new_master,
2676 migrate->master);
2677
2678unlock:
2679 spin_unlock(&dlm->master_lock);
2680 spin_unlock(&dlm->spinlock);
2681
2682 if (oldmle) {
2683 /* master is known, detach if not already detached */
2684 dlm_mle_detach_hb_events(dlm, oldmle);
2685 dlm_put_mle(oldmle);
2686 }
2687
2688 if (res)
2689 dlm_lockres_put(res);
2690leave:
2691 dlm_put(dlm);
2692 return ret;
2693}
2694
2695/* must be holding dlm->spinlock and dlm->master_lock
2696 * when adding a migration mle, we can clear any other mles
2697 * in the master list because we know with certainty that
2698 * the master is "master". so we remove any old mle from
2699 * the list after setting it's master field, and then add
2700 * the new migration mle. this way we can hold with the rule
2701 * of having only one mle for a given lock name at all times. */
2702static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
2703 struct dlm_lock_resource *res,
2704 struct dlm_master_list_entry *mle,
2705 struct dlm_master_list_entry **oldmle,
2706 const char *name, unsigned int namelen,
2707 u8 new_master, u8 master)
2708{
2709 int found;
2710 int ret = 0;
2711
2712 *oldmle = NULL;
2713
2714 mlog_entry_void();
2715
2716 assert_spin_locked(&dlm->spinlock);
2717 assert_spin_locked(&dlm->master_lock);
2718
2719 /* caller is responsible for any ref taken here on oldmle */
2720 found = dlm_find_mle(dlm, oldmle, (char *)name, namelen);
2721 if (found) {
2722 struct dlm_master_list_entry *tmp = *oldmle;
2723 spin_lock(&tmp->spinlock);
2724 if (tmp->type == DLM_MLE_MIGRATION) {
2725 if (master == dlm->node_num) {
2726 /* ah another process raced me to it */
2727 mlog(0, "tried to migrate %.*s, but some "
2728 "process beat me to it\n",
2729 namelen, name);
2730 ret = -EEXIST;
2731 } else {
2732 /* bad. 2 NODES are trying to migrate! */
2733 mlog(ML_ERROR, "migration error mle: "
2734 "master=%u new_master=%u // request: "
2735 "master=%u new_master=%u // "
2736 "lockres=%.*s\n",
2737 tmp->master, tmp->new_master,
2738 master, new_master,
2739 namelen, name);
2740 BUG();
2741 }
2742 } else {
2743 /* this is essentially what assert_master does */
2744 tmp->master = master;
2745 atomic_set(&tmp->woken, 1);
2746 wake_up(&tmp->wq);
2747 /* remove it from the list so that only one
2748 * mle will be found */
2749 list_del_init(&tmp->list);
da01ad05 2750 __dlm_mle_detach_hb_events(dlm, mle);
6714d8e8
KH		 2751 }
2752 spin_unlock(&tmp->spinlock);
2753 }
2754
2755 /* now add a migration mle to the tail of the list */
2756 dlm_init_mle(mle, DLM_MLE_MIGRATION, dlm, res, name, namelen);
2757 mle->new_master = new_master;
2758 mle->master = master;
2759 /* do this for consistency with other mle types */
2760 set_bit(new_master, mle->maybe_map);
2761 list_add(&mle->list, &dlm->master_list);
2762
2763 return ret;
2764}
2765
2766
2767void dlm_clean_master_list(struct dlm_ctxt *dlm, u8 dead_node)
2768{
2769 struct list_head *iter, *iter2;
2770 struct dlm_master_list_entry *mle;
2771 struct dlm_lock_resource *res;
a3d33291 2772 unsigned int hash;
6714d8e8
KH		 2773
2774 mlog_entry("dlm=%s, dead node=%u\n", dlm->name, dead_node);
2775top:
2776 assert_spin_locked(&dlm->spinlock);
2777
2778 /* clean the master list */
2779 spin_lock(&dlm->master_lock);
2780 list_for_each_safe(iter, iter2, &dlm->master_list) {
2781 mle = list_entry(iter, struct dlm_master_list_entry, list);
2782
2783 BUG_ON(mle->type != DLM_MLE_BLOCK &&
2784 mle->type != DLM_MLE_MASTER &&
2785 mle->type != DLM_MLE_MIGRATION);
2786
2787 /* MASTER mles are initiated locally. the waiting
2788 * process will notice the node map change
2789 * shortly. let that happen as normal. */
2790 if (mle->type == DLM_MLE_MASTER)
2791 continue;
2792
2793
2794 /* BLOCK mles are initiated by other nodes.
2795 * need to clean up if the dead node would have
2796 * been the master. */
2797 if (mle->type == DLM_MLE_BLOCK) {
2798 int bit;
2799
2800 spin_lock(&mle->spinlock);
2801 bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
2802 if (bit != dead_node) {
2803 mlog(0, "mle found, but dead node %u would "
2804 "not have been master\n", dead_node);
2805 spin_unlock(&mle->spinlock);
2806 } else {
2807 /* must drop the refcount by one since the
2808 * assert_master will never arrive. this
2809 * may result in the mle being unlinked and
2810 * freed, but there may still be a process
2811 * waiting in the dlmlock path which is fine. */
3b3b84a8 2812 mlog(0, "node %u was expected master\n",
6714d8e8
KH		 2813 dead_node);
2814 atomic_set(&mle->woken, 1);
2815 spin_unlock(&mle->spinlock);
2816 wake_up(&mle->wq);
f671c09b
KH		 2817 /* do not need events any longer, so detach
2818 * from heartbeat */
2819 __dlm_mle_detach_hb_events(dlm, mle);
6714d8e8
KH		 2820 __dlm_put_mle(mle);
2821 }
2822 continue;
2823 }
2824
2825 /* everything else is a MIGRATION mle */
2826
2827 /* the rule for MIGRATION mles is that the master
2828 * becomes UNKNOWN if *either* the original or
2829 * the new master dies. all UNKNOWN lockreses
2830 * are sent to whichever node becomes the recovery
2831 * master. the new master is responsible for
2832 * determining if there is still a master for
2833 * this lockres, or if he needs to take over
2834 * mastery. either way, this node should expect
2835 * another message to resolve this. */
2836 if (mle->master != dead_node &&
2837 mle->new_master != dead_node)
2838 continue;
2839
2840 /* if we have reached this point, this mle needs to
2841 * be removed from the list and freed. */
2842
2843 /* remove from the list early. NOTE: unlinking
2844 * list_head while in list_for_each_safe */
da01ad05 2845 __dlm_mle_detach_hb_events(dlm, mle);
6714d8e8
KH		 2846 spin_lock(&mle->spinlock);
2847 list_del_init(&mle->list);
2848 atomic_set(&mle->woken, 1);
2849 spin_unlock(&mle->spinlock);
2850 wake_up(&mle->wq);
2851
aa852354
KH		 2852 mlog(0, "%s: node %u died during migration from "
2853 "%u to %u!\n", dlm->name, dead_node,
6714d8e8
KH		 2854 mle->master, mle->new_master);
2855 /* if there is a lockres associated with this
2856 * mle, find it and set its owner to UNKNOWN */
a3d33291 2857 hash = dlm_lockid_hash(mle->u.name.name, mle->u.name.len);
6714d8e8 2858 res = __dlm_lookup_lockres(dlm, mle->u.name.name,
a3d33291 2859 mle->u.name.len, hash);
6714d8e8
KH		 2860 if (res) {
2861 /* unfortunately if we hit this rare case, our
2862 * lock ordering is messed. we need to drop
2863 * the master lock so that we can take the
2864 * lockres lock, meaning that we will have to
2865 * restart from the head of list. */
2866 spin_unlock(&dlm->master_lock);
2867
2868 /* move lockres onto recovery list */
2869 spin_lock(&res->spinlock);
2870 dlm_set_lockres_owner(dlm, res,
2871 DLM_LOCK_RES_OWNER_UNKNOWN);
2872 dlm_move_lockres_to_recovery_list(dlm, res);
2873 spin_unlock(&res->spinlock);
2874 dlm_lockres_put(res);
2875
f671c09b
KH		 2876 /* about to get rid of mle, detach from heartbeat */
2877 __dlm_mle_detach_hb_events(dlm, mle);
2878
6714d8e8
KH		 2879 /* dump the mle */
2880 spin_lock(&dlm->master_lock);
2881 __dlm_put_mle(mle);
2882 spin_unlock(&dlm->master_lock);
2883
2884 /* restart */
2885 goto top;
2886 }
2887
2888 /* this may be the last reference */
2889 __dlm_put_mle(mle);
2890 }
2891 spin_unlock(&dlm->master_lock);
2892}
2893
2894
2895int dlm_finish_migration(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
2896 u8 old_master)
2897{
2898 struct dlm_node_iter iter;
2899 int ret = 0;
2900
2901 spin_lock(&dlm->spinlock);
2902 dlm_node_iter_init(dlm->domain_map, &iter);
2903 clear_bit(old_master, iter.node_map);
2904 clear_bit(dlm->node_num, iter.node_map);
2905 spin_unlock(&dlm->spinlock);
2906
2907 mlog(0, "now time to do a migrate request to other nodes\n");
2908 ret = dlm_do_migrate_request(dlm, res, old_master,
2909 dlm->node_num, &iter);
2910 if (ret < 0) {
2911 mlog_errno(ret);
2912 goto leave;
2913 }
2914
2915 mlog(0, "doing assert master of %.*s to all except the original node\n",
2916 res->lockname.len, res->lockname.name);
2917 /* this call now finishes out the nodemap
2918 * even if one or more nodes die */
2919 ret = dlm_do_assert_master(dlm, res->lockname.name,
2920 res->lockname.len, iter.node_map,
2921 DLM_ASSERT_MASTER_FINISH_MIGRATION);
2922 if (ret < 0) {
2923 /* no longer need to retry. all living nodes contacted. */
2924 mlog_errno(ret);
2925 ret = 0;
2926 }
2927
2928 memset(iter.node_map, 0, sizeof(iter.node_map));
2929 set_bit(old_master, iter.node_map);
2930 mlog(0, "doing assert master of %.*s back to %u\n",
2931 res->lockname.len, res->lockname.name, old_master);
2932 ret = dlm_do_assert_master(dlm, res->lockname.name,
2933 res->lockname.len, iter.node_map,
2934 DLM_ASSERT_MASTER_FINISH_MIGRATION);
2935 if (ret < 0) {
2936 mlog(0, "assert master to original master failed "
2937 "with %d.\n", ret);
2938 /* the only nonzero status here would be because of
2939 * a dead original node. we're done. */
2940 ret = 0;
2941 }
2942
2943 /* all done, set the owner, clear the flag */
2944 spin_lock(&res->spinlock);
2945 dlm_set_lockres_owner(dlm, res, dlm->node_num);
2946 res->state &= ~DLM_LOCK_RES_MIGRATING;
2947 spin_unlock(&res->spinlock);
2948 /* re-dirty it on the new master */
2949 dlm_kick_thread(dlm, res);
2950 wake_up(&res->wq);
2951leave:
2952 return ret;
2953}
2954
2955/*
2956 * LOCKRES AST REFCOUNT
2957 * this is integral to migration
2958 */
2959
2960/* for future intent to call an ast, reserve one ahead of time.
2961 * this should be called only after waiting on the lockres
2962 * with dlm_wait_on_lockres, and while still holding the
2963 * spinlock after the call. */
2964void __dlm_lockres_reserve_ast(struct dlm_lock_resource *res)
2965{
2966 assert_spin_locked(&res->spinlock);
2967 if (res->state & DLM_LOCK_RES_MIGRATING) {
2968 __dlm_print_one_lock_resource(res);
2969 }
2970 BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
2971
2972 atomic_inc(&res->asts_reserved);
2973}
2974
2975/*
2976 * used to drop the reserved ast, either because it went unused,
2977 * or because the ast/bast was actually called.
2978 *
2979 * also, if there is a pending migration on this lockres,
2980 * and this was the last pending ast on the lockres,
2981 * atomically set the MIGRATING flag before we drop the lock.
2982 * this is how we ensure that migration can proceed with no
2983 * asts in progress. note that it is ok if the state of the
2984 * queues is such that a lock should be granted in the future
2985 * or that a bast should be fired, because the new master will
2986 * shuffle the lists on this lockres as soon as it is migrated.
2987 */
2988void dlm_lockres_release_ast(struct dlm_ctxt *dlm,
2989 struct dlm_lock_resource *res)
2990{
2991 if (!atomic_dec_and_lock(&res->asts_reserved, &res->spinlock))
2992 return;
2993
2994 if (!res->migration_pending) {
2995 spin_unlock(&res->spinlock);
2996 return;
2997 }
2998
2999 BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
3000 res->migration_pending = 0;
3001 res->state |= DLM_LOCK_RES_MIGRATING;
3002 spin_unlock(&res->spinlock);
3003 wake_up(&res->wq);
3004 wake_up(&dlm->migration_wq);
3005}
Linux 6.x block layer and io_uring tree(s)