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ocfs2_dlm: fix cluster-wide refcounting of lock resources
[linux-2.6-block.git] / fs / ocfs2 / dlm / dlmmaster.c
CommitLineData
6714d8e8
KH		 1/* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
3 *
4 * dlmmod.c
5 *
6 * standalone DLM module
7 *
8 * Copyright (C) 2004 Oracle. All rights reserved.
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public
12 * License as published by the Free Software Foundation; either
13 * version 2 of the License, or (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public
21 * License along with this program; if not, write to the
22 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
23 * Boston, MA 021110-1307, USA.
24 *
25 */
26
27
28#include <linux/module.h>
29#include <linux/fs.h>
30#include <linux/types.h>
31#include <linux/slab.h>
32#include <linux/highmem.h>
33#include <linux/utsname.h>
34#include <linux/init.h>
35#include <linux/sysctl.h>
36#include <linux/random.h>
37#include <linux/blkdev.h>
38#include <linux/socket.h>
39#include <linux/inet.h>
40#include <linux/spinlock.h>
41#include <linux/delay.h>
42
43
44#include "cluster/heartbeat.h"
45#include "cluster/nodemanager.h"
46#include "cluster/tcp.h"
47
48#include "dlmapi.h"
49#include "dlmcommon.h"
82353b59 50#include "dlmdomain.h"
6714d8e8
KH		 51
52#define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_MASTER)
53#include "cluster/masklog.h"
54
55enum dlm_mle_type {
56 DLM_MLE_BLOCK,
57 DLM_MLE_MASTER,
58 DLM_MLE_MIGRATION
59};
60
61struct dlm_lock_name
62{
63 u8 len;
64 u8 name[DLM_LOCKID_NAME_MAX];
65};
66
67struct dlm_master_list_entry
68{
69 struct list_head list;
70 struct list_head hb_events;
71 struct dlm_ctxt *dlm;
72 spinlock_t spinlock;
73 wait_queue_head_t wq;
74 atomic_t woken;
75 struct kref mle_refs;
a2bf0477 76 int inuse;
6714d8e8
KH		 77 unsigned long maybe_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
78 unsigned long vote_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
79 unsigned long response_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
80 unsigned long node_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
81 u8 master;
82 u8 new_master;
83 enum dlm_mle_type type;
84 struct o2hb_callback_func mle_hb_up;
85 struct o2hb_callback_func mle_hb_down;
86 union {
87 struct dlm_lock_resource *res;
88 struct dlm_lock_name name;
89 } u;
90};
91
92static void dlm_mle_node_down(struct dlm_ctxt *dlm,
93 struct dlm_master_list_entry *mle,
94 struct o2nm_node *node,
95 int idx);
96static void dlm_mle_node_up(struct dlm_ctxt *dlm,
97 struct dlm_master_list_entry *mle,
98 struct o2nm_node *node,
99 int idx);
100
101static void dlm_assert_master_worker(struct dlm_work_item *item, void *data);
ba2bf218
KH		 102static int dlm_do_assert_master(struct dlm_ctxt *dlm,
103 struct dlm_lock_resource *res,
104 void *nodemap, u32 flags);
6714d8e8
KH		 105
106static inline int dlm_mle_equal(struct dlm_ctxt *dlm,
107 struct dlm_master_list_entry *mle,
108 const char *name,
109 unsigned int namelen)
110{
111 struct dlm_lock_resource *res;
112
113 if (dlm != mle->dlm)
114 return 0;
115
116 if (mle->type == DLM_MLE_BLOCK ||
117 mle->type == DLM_MLE_MIGRATION) {
118 if (namelen != mle->u.name.len ||
119 memcmp(name, mle->u.name.name, namelen)!=0)
120 return 0;
121 } else {
122 res = mle->u.res;
123 if (namelen != res->lockname.len ||
124 memcmp(res->lockname.name, name, namelen) != 0)
125 return 0;
126 }
127 return 1;
128}
129
95883719 130#define dlm_print_nodemap(m) _dlm_print_nodemap(m,#m)
8a9343fa 131static void _dlm_print_nodemap(unsigned long *map, const char *mapname)
95883719
KH		 132{
133 int i;
134 printk("%s=[ ", mapname);
135 for (i=0; i<O2NM_MAX_NODES; i++)
136 if (test_bit(i, map))
137 printk("%d ", i);
138 printk("]");
139}
140
8a9343fa 141static void dlm_print_one_mle(struct dlm_master_list_entry *mle)
6714d8e8 142{
95883719 143 int refs;
6714d8e8
KH		 144 char *type;
145 char attached;
146 u8 master;
147 unsigned int namelen;
148 const char *name;
149 struct kref *k;
95883719
KH		 150 unsigned long *maybe = mle->maybe_map,
151 *vote = mle->vote_map,
152 *resp = mle->response_map,
153 *node = mle->node_map;
6714d8e8
KH		 154
155 k = &mle->mle_refs;
156 if (mle->type == DLM_MLE_BLOCK)
157 type = "BLK";
158 else if (mle->type == DLM_MLE_MASTER)
159 type = "MAS";
160 else
161 type = "MIG";
162 refs = atomic_read(&k->refcount);
163 master = mle->master;
164 attached = (list_empty(&mle->hb_events) ? 'N' : 'Y');
165
166 if (mle->type != DLM_MLE_MASTER) {
167 namelen = mle->u.name.len;
168 name = mle->u.name.name;
169 } else {
170 namelen = mle->u.res->lockname.len;
171 name = mle->u.res->lockname.name;
172 }
173
95883719
KH		 174 mlog(ML_NOTICE, "%.*s: %3s refs=%3d mas=%3u new=%3u evt=%c inuse=%d ",
175 namelen, name, type, refs, master, mle->new_master, attached,
176 mle->inuse);
177 dlm_print_nodemap(maybe);
178 printk(", ");
179 dlm_print_nodemap(vote);
180 printk(", ");
181 dlm_print_nodemap(resp);
182 printk(", ");
183 dlm_print_nodemap(node);
184 printk(", ");
185 printk("\n");
6714d8e8
KH		 186}
187
8a9343fa
MF		 188#if 0
189/* Code here is included but defined out as it aids debugging */
190
6714d8e8
KH		 191static void dlm_dump_mles(struct dlm_ctxt *dlm)
192{
193 struct dlm_master_list_entry *mle;
194 struct list_head *iter;
195
196 mlog(ML_NOTICE, "dumping all mles for domain %s:\n", dlm->name);
6714d8e8
KH		 197 spin_lock(&dlm->master_lock);
198 list_for_each(iter, &dlm->master_list) {
199 mle = list_entry(iter, struct dlm_master_list_entry, list);
200 dlm_print_one_mle(mle);
201 }
202 spin_unlock(&dlm->master_lock);
203}
204
6714d8e8
KH		 205int dlm_dump_all_mles(const char __user *data, unsigned int len)
206{
207 struct list_head *iter;
208 struct dlm_ctxt *dlm;
209
210 spin_lock(&dlm_domain_lock);
211 list_for_each(iter, &dlm_domains) {
212 dlm = list_entry (iter, struct dlm_ctxt, list);
213 mlog(ML_NOTICE, "found dlm: %p, name=%s\n", dlm, dlm->name);
214 dlm_dump_mles(dlm);
215 }
216 spin_unlock(&dlm_domain_lock);
217 return len;
218}
219EXPORT_SYMBOL_GPL(dlm_dump_all_mles);
220
221#endif /* 0 */
222
223
e18b890b 224static struct kmem_cache *dlm_mle_cache = NULL;
6714d8e8
KH		 225
226
227static void dlm_mle_release(struct kref *kref);
228static void dlm_init_mle(struct dlm_master_list_entry *mle,
229 enum dlm_mle_type type,
230 struct dlm_ctxt *dlm,
231 struct dlm_lock_resource *res,
232 const char *name,
233 unsigned int namelen);
234static void dlm_put_mle(struct dlm_master_list_entry *mle);
235static void __dlm_put_mle(struct dlm_master_list_entry *mle);
236static int dlm_find_mle(struct dlm_ctxt *dlm,
237 struct dlm_master_list_entry **mle,
238 char *name, unsigned int namelen);
239
ba2bf218
KH		 240static int dlm_do_master_request(struct dlm_lock_resource *res,
241 struct dlm_master_list_entry *mle, int to);
6714d8e8
KH		 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;
ba2bf218 691 res->inflight_locks = 0;
6714d8e8
KH		 692
693 kref_init(&res->refs);
694
695 /* just for consistency */
696 spin_lock(&res->spinlock);
697 dlm_set_lockres_owner(dlm, res, DLM_LOCK_RES_OWNER_UNKNOWN);
698 spin_unlock(&res->spinlock);
699
700 res->state = DLM_LOCK_RES_IN_PROGRESS;
701
702 res->last_used = 0;
703
704 memset(res->lvb, 0, DLM_LVB_LEN);
ba2bf218 705 memset(res->refmap, 0, sizeof(res->refmap));
6714d8e8
KH		 706}
707
708struct dlm_lock_resource *dlm_new_lockres(struct dlm_ctxt *dlm,
709 const char *name,
710 unsigned int namelen)
711{
712 struct dlm_lock_resource *res;
713
ad8100e0 714 res = kmalloc(sizeof(struct dlm_lock_resource), GFP_NOFS);
6714d8e8
KH		 715 if (!res)
716 return NULL;
717
ad8100e0 718 res->lockname.name = kmalloc(namelen, GFP_NOFS);
6714d8e8
KH		 719 if (!res->lockname.name) {
720 kfree(res);
721 return NULL;
722 }
723
724 dlm_init_lockres(dlm, res, name, namelen);
725 return res;
726}
727
ba2bf218
KH		 728void __dlm_lockres_grab_inflight_ref(struct dlm_ctxt *dlm,
729 struct dlm_lock_resource *res,
730 int new_lockres,
731 const char *file,
732 int line)
733{
734 if (!new_lockres)
735 assert_spin_locked(&res->spinlock);
736
737 if (!test_bit(dlm->node_num, res->refmap)) {
738 BUG_ON(res->inflight_locks != 0);
739 dlm_lockres_set_refmap_bit(dlm->node_num, res);
740 }
741 res->inflight_locks++;
742 mlog(0, "%s:%.*s: inflight++: now %u\n",
743 dlm->name, res->lockname.len, res->lockname.name,
744 res->inflight_locks);
745}
746
747void __dlm_lockres_drop_inflight_ref(struct dlm_ctxt *dlm,
748 struct dlm_lock_resource *res,
749 const char *file,
750 int line)
751{
752 assert_spin_locked(&res->spinlock);
753
754 BUG_ON(res->inflight_locks == 0);
755 res->inflight_locks--;
756 mlog(0, "%s:%.*s: inflight--: now %u\n",
757 dlm->name, res->lockname.len, res->lockname.name,
758 res->inflight_locks);
759 if (res->inflight_locks == 0)
760 dlm_lockres_clear_refmap_bit(dlm->node_num, res);
761 wake_up(&res->wq);
762}
763
6714d8e8
KH		 764/*
765 * lookup a lock resource by name.
766 * may already exist in the hashtable.
767 * lockid is null terminated
768 *
769 * if not, allocate enough for the lockres and for
770 * the temporary structure used in doing the mastering.
771 *
772 * also, do a lookup in the dlm->master_list to see
773 * if another node has begun mastering the same lock.
774 * if so, there should be a block entry in there
775 * for this name, and we should *not* attempt to master
776 * the lock here. need to wait around for that node
777 * to assert_master (or die).
778 *
779 */
780struct dlm_lock_resource * dlm_get_lock_resource(struct dlm_ctxt *dlm,
781 const char *lockid,
3384f3df 782 int namelen,
6714d8e8
KH		 783 int flags)
784{
785 struct dlm_lock_resource *tmpres=NULL, *res=NULL;
786 struct dlm_master_list_entry *mle = NULL;
787 struct dlm_master_list_entry *alloc_mle = NULL;
788 int blocked = 0;
789 int ret, nodenum;
790 struct dlm_node_iter iter;
3384f3df 791 unsigned int hash;
6714d8e8 792 int tries = 0;
c03872f5 793 int bit, wait_on_recovery = 0;
ba2bf218 794 int drop_inflight_if_nonlocal = 0;
6714d8e8
KH		 795
796 BUG_ON(!lockid);
797
a3d33291 798 hash = dlm_lockid_hash(lockid, namelen);
6714d8e8
KH		 799
800 mlog(0, "get lockres %s (len %d)\n", lockid, namelen);
801
802lookup:
803 spin_lock(&dlm->spinlock);
ba2bf218 804 tmpres = __dlm_lookup_lockres_full(dlm, lockid, namelen, hash);
6714d8e8 805 if (tmpres) {
ba2bf218
KH		 806 int dropping_ref = 0;
807
808 spin_lock(&tmpres->spinlock);
809 if (tmpres->owner == dlm->node_num) {
810 BUG_ON(tmpres->state & DLM_LOCK_RES_DROPPING_REF);
811 dlm_lockres_grab_inflight_ref(dlm, tmpres);
812 } else if (tmpres->state & DLM_LOCK_RES_DROPPING_REF)
813 dropping_ref = 1;
814 spin_unlock(&tmpres->spinlock);
6714d8e8 815 spin_unlock(&dlm->spinlock);
ba2bf218
KH		 816
817 /* wait until done messaging the master, drop our ref to allow
818 * the lockres to be purged, start over. */
819 if (dropping_ref) {
820 spin_lock(&tmpres->spinlock);
821 __dlm_wait_on_lockres_flags(tmpres, DLM_LOCK_RES_DROPPING_REF);
822 spin_unlock(&tmpres->spinlock);
823 dlm_lockres_put(tmpres);
824 tmpres = NULL;
825 goto lookup;
826 }
827
6714d8e8
KH		 828 mlog(0, "found in hash!\n");
829 if (res)
830 dlm_lockres_put(res);
831 res = tmpres;
832 goto leave;
833 }
834
835 if (!res) {
836 spin_unlock(&dlm->spinlock);
837 mlog(0, "allocating a new resource\n");
838 /* nothing found and we need to allocate one. */
839 alloc_mle = (struct dlm_master_list_entry *)
ad8100e0 840 kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
6714d8e8
KH		 841 if (!alloc_mle)
842 goto leave;
843 res = dlm_new_lockres(dlm, lockid, namelen);
844 if (!res)
845 goto leave;
846 goto lookup;
847 }
848
849 mlog(0, "no lockres found, allocated our own: %p\n", res);
850
851 if (flags & LKM_LOCAL) {
852 /* caller knows it's safe to assume it's not mastered elsewhere
853 * DONE! return right away */
854 spin_lock(&res->spinlock);
855 dlm_change_lockres_owner(dlm, res, dlm->node_num);
856 __dlm_insert_lockres(dlm, res);
ba2bf218 857 dlm_lockres_grab_inflight_ref(dlm, res);
6714d8e8
KH		 858 spin_unlock(&res->spinlock);
859 spin_unlock(&dlm->spinlock);
860 /* lockres still marked IN_PROGRESS */
861 goto wake_waiters;
862 }
863
864 /* check master list to see if another node has started mastering it */
865 spin_lock(&dlm->master_lock);
866
867 /* if we found a block, wait for lock to be mastered by another node */
868 blocked = dlm_find_mle(dlm, &mle, (char *)lockid, namelen);
869 if (blocked) {
ba2bf218 870 int mig;
6714d8e8
KH		 871 if (mle->type == DLM_MLE_MASTER) {
872 mlog(ML_ERROR, "master entry for nonexistent lock!\n");
873 BUG();
ba2bf218
KH		 874 }
875 mig = (mle->type == DLM_MLE_MIGRATION);
876 /* if there is a migration in progress, let the migration
877 * finish before continuing. we can wait for the absence
878 * of the MIGRATION mle: either the migrate finished or
879 * one of the nodes died and the mle was cleaned up.
880 * if there is a BLOCK here, but it already has a master
881 * set, we are too late. the master does not have a ref
882 * for us in the refmap. detach the mle and drop it.
883 * either way, go back to the top and start over. */
884 if (mig || mle->master != O2NM_MAX_NODES) {
885 BUG_ON(mig && mle->master == dlm->node_num);
886 /* we arrived too late. the master does not
887 * have a ref for us. retry. */
888 mlog(0, "%s:%.*s: late on %s\n",
889 dlm->name, namelen, lockid,
890 mig ? "MIGRATION" : "BLOCK");
6714d8e8 891 spin_unlock(&dlm->master_lock);
6714d8e8
KH		 892 spin_unlock(&dlm->spinlock);
893
894 /* master is known, detach */
ba2bf218
KH		 895 if (!mig)
896 dlm_mle_detach_hb_events(dlm, mle);
6714d8e8
KH		 897 dlm_put_mle(mle);
898 mle = NULL;
ba2bf218
KH		 899 /* this is lame, but we cant wait on either
900 * the mle or lockres waitqueue here */
901 if (mig)
902 msleep(100);
903 goto lookup;
6714d8e8
KH		 904 }
905 } else {
906 /* go ahead and try to master lock on this node */
907 mle = alloc_mle;
908 /* make sure this does not get freed below */
909 alloc_mle = NULL;
910 dlm_init_mle(mle, DLM_MLE_MASTER, dlm, res, NULL, 0);
911 set_bit(dlm->node_num, mle->maybe_map);
912 list_add(&mle->list, &dlm->master_list);
c03872f5
KH		 913
914 /* still holding the dlm spinlock, check the recovery map
915 * to see if there are any nodes that still need to be
916 * considered. these will not appear in the mle nodemap
917 * but they might own this lockres. wait on them. */
918 bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
919 if (bit < O2NM_MAX_NODES) {
920 mlog(ML_NOTICE, "%s:%.*s: at least one node (%d) to"
921 "recover before lock mastery can begin\n",
922 dlm->name, namelen, (char *)lockid, bit);
923 wait_on_recovery = 1;
924 }
6714d8e8
KH		 925 }
926
927 /* at this point there is either a DLM_MLE_BLOCK or a
928 * DLM_MLE_MASTER on the master list, so it's safe to add the
929 * lockres to the hashtable. anyone who finds the lock will
930 * still have to wait on the IN_PROGRESS. */
931
932 /* finally add the lockres to its hash bucket */
933 __dlm_insert_lockres(dlm, res);
ba2bf218
KH		 934 /* since this lockres is new it doesnt not require the spinlock */
935 dlm_lockres_grab_inflight_ref_new(dlm, res);
936
937 /* if this node does not become the master make sure to drop
938 * this inflight reference below */
939 drop_inflight_if_nonlocal = 1;
940
6714d8e8
KH		 941 /* get an extra ref on the mle in case this is a BLOCK
942 * if so, the creator of the BLOCK may try to put the last
943 * ref at this time in the assert master handler, so we
944 * need an extra one to keep from a bad ptr deref. */
a2bf0477 945 dlm_get_mle_inuse(mle);
6714d8e8
KH		 946 spin_unlock(&dlm->master_lock);
947 spin_unlock(&dlm->spinlock);
948
e7e69eb3 949redo_request:
c03872f5
KH		 950 while (wait_on_recovery) {
951 /* any cluster changes that occurred after dropping the
952 * dlm spinlock would be detectable be a change on the mle,
953 * so we only need to clear out the recovery map once. */
954 if (dlm_is_recovery_lock(lockid, namelen)) {
955 mlog(ML_NOTICE, "%s: recovery map is not empty, but "
956 "must master $RECOVERY lock now\n", dlm->name);
957 if (!dlm_pre_master_reco_lockres(dlm, res))
958 wait_on_recovery = 0;
959 else {
960 mlog(0, "%s: waiting 500ms for heartbeat state "
961 "change\n", dlm->name);
962 msleep(500);
963 }
964 continue;
965 }
966
967 dlm_kick_recovery_thread(dlm);
aa087b84 968 msleep(1000);
c03872f5
KH		 969 dlm_wait_for_recovery(dlm);
970
971 spin_lock(&dlm->spinlock);
972 bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
973 if (bit < O2NM_MAX_NODES) {
974 mlog(ML_NOTICE, "%s:%.*s: at least one node (%d) to"
975 "recover before lock mastery can begin\n",
976 dlm->name, namelen, (char *)lockid, bit);
977 wait_on_recovery = 1;
978 } else
979 wait_on_recovery = 0;
980 spin_unlock(&dlm->spinlock);
b7084ab5
KH		 981
982 if (wait_on_recovery)
983 dlm_wait_for_node_recovery(dlm, bit, 10000);
c03872f5
KH		 984 }
985
6714d8e8
KH		 986 /* must wait for lock to be mastered elsewhere */
987 if (blocked)
988 goto wait;
989
6714d8e8
KH		 990 ret = -EINVAL;
991 dlm_node_iter_init(mle->vote_map, &iter);
992 while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
ba2bf218 993 ret = dlm_do_master_request(res, mle, nodenum);
6714d8e8
KH		 994 if (ret < 0)
995 mlog_errno(ret);
996 if (mle->master != O2NM_MAX_NODES) {
997 /* found a master ! */
9c6510a5
KH		 998 if (mle->master <= nodenum)
999 break;
1000 /* if our master request has not reached the master
1001 * yet, keep going until it does. this is how the
1002 * master will know that asserts are needed back to
1003 * the lower nodes. */
1004 mlog(0, "%s:%.*s: requests only up to %u but master "
1005 "is %u, keep going\n", dlm->name, namelen,
1006 lockid, nodenum, mle->master);
6714d8e8
KH		 1007 }
1008 }
1009
1010wait:
1011 /* keep going until the response map includes all nodes */
1012 ret = dlm_wait_for_lock_mastery(dlm, res, mle, &blocked);
1013 if (ret < 0) {
e7e69eb3 1014 wait_on_recovery = 1;
6714d8e8
KH		 1015 mlog(0, "%s:%.*s: node map changed, redo the "
1016 "master request now, blocked=%d\n",
1017 dlm->name, res->lockname.len,
1018 res->lockname.name, blocked);
1019 if (++tries > 20) {
1020 mlog(ML_ERROR, "%s:%.*s: spinning on "
1021 "dlm_wait_for_lock_mastery, blocked=%d\n",
1022 dlm->name, res->lockname.len,
1023 res->lockname.name, blocked);
1024 dlm_print_one_lock_resource(res);
8a9343fa 1025 dlm_print_one_mle(mle);
6714d8e8
KH		 1026 tries = 0;
1027 }
1028 goto redo_request;
1029 }
1030
1031 mlog(0, "lockres mastered by %u\n", res->owner);
1032 /* make sure we never continue without this */
1033 BUG_ON(res->owner == O2NM_MAX_NODES);
1034
1035 /* master is known, detach if not already detached */
1036 dlm_mle_detach_hb_events(dlm, mle);
1037 dlm_put_mle(mle);
1038 /* put the extra ref */
a2bf0477 1039 dlm_put_mle_inuse(mle);
6714d8e8
KH		 1040
1041wake_waiters:
1042 spin_lock(&res->spinlock);
ba2bf218
KH		 1043 if (res->owner != dlm->node_num && drop_inflight_if_nonlocal)
1044 dlm_lockres_drop_inflight_ref(dlm, res);
6714d8e8
KH		 1045 res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
1046 spin_unlock(&res->spinlock);
1047 wake_up(&res->wq);
1048
1049leave:
1050 /* need to free the unused mle */
1051 if (alloc_mle)
1052 kmem_cache_free(dlm_mle_cache, alloc_mle);
1053
1054 return res;
1055}
1056
1057
1058#define DLM_MASTERY_TIMEOUT_MS 5000
1059
1060static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
1061 struct dlm_lock_resource *res,
1062 struct dlm_master_list_entry *mle,
1063 int *blocked)
1064{
1065 u8 m;
1066 int ret, bit;
1067 int map_changed, voting_done;
1068 int assert, sleep;
1069
1070recheck:
1071 ret = 0;
1072 assert = 0;
1073
1074 /* check if another node has already become the owner */
1075 spin_lock(&res->spinlock);
1076 if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
9c6510a5
KH		 1077 mlog(0, "%s:%.*s: owner is suddenly %u\n", dlm->name,
1078 res->lockname.len, res->lockname.name, res->owner);
6714d8e8 1079 spin_unlock(&res->spinlock);
9c6510a5
KH		 1080 /* this will cause the master to re-assert across
1081 * the whole cluster, freeing up mles */
588e0090 1082 if (res->owner != dlm->node_num) {
ba2bf218 1083 ret = dlm_do_master_request(res, mle, res->owner);
588e0090
KH		 1084 if (ret < 0) {
1085 /* give recovery a chance to run */
1086 mlog(ML_ERROR, "link to %u went down?: %d\n", res->owner, ret);
1087 msleep(500);
1088 goto recheck;
1089 }
9c6510a5
KH		 1090 }
1091 ret = 0;
6714d8e8
KH		 1092 goto leave;
1093 }
1094 spin_unlock(&res->spinlock);
1095
1096 spin_lock(&mle->spinlock);
1097 m = mle->master;
1098 map_changed = (memcmp(mle->vote_map, mle->node_map,
1099 sizeof(mle->vote_map)) != 0);
1100 voting_done = (memcmp(mle->vote_map, mle->response_map,
1101 sizeof(mle->vote_map)) == 0);
1102
1103 /* restart if we hit any errors */
1104 if (map_changed) {
1105 int b;
1106 mlog(0, "%s: %.*s: node map changed, restarting\n",
1107 dlm->name, res->lockname.len, res->lockname.name);
1108 ret = dlm_restart_lock_mastery(dlm, res, mle, *blocked);
1109 b = (mle->type == DLM_MLE_BLOCK);
1110 if ((*blocked && !b) || (!*blocked && b)) {
1111 mlog(0, "%s:%.*s: status change: old=%d new=%d\n",
1112 dlm->name, res->lockname.len, res->lockname.name,
1113 *blocked, b);
1114 *blocked = b;
1115 }
1116 spin_unlock(&mle->spinlock);
1117 if (ret < 0) {
1118 mlog_errno(ret);
1119 goto leave;
1120 }
1121 mlog(0, "%s:%.*s: restart lock mastery succeeded, "
1122 "rechecking now\n", dlm->name, res->lockname.len,
1123 res->lockname.name);
1124 goto recheck;
aa852354
KH		 1125 } else {
1126 if (!voting_done) {
1127 mlog(0, "map not changed and voting not done "
1128 "for %s:%.*s\n", dlm->name, res->lockname.len,
1129 res->lockname.name);
1130 }
6714d8e8
KH		 1131 }
1132
1133 if (m != O2NM_MAX_NODES) {
1134 /* another node has done an assert!
1135 * all done! */
1136 sleep = 0;
1137 } else {
1138 sleep = 1;
1139 /* have all nodes responded? */
1140 if (voting_done && !*blocked) {
1141 bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
1142 if (dlm->node_num <= bit) {
1143 /* my node number is lowest.
1144 * now tell other nodes that I am
1145 * mastering this. */
1146 mle->master = dlm->node_num;
ba2bf218
KH		 1147 /* ref was grabbed in get_lock_resource
1148 * will be dropped in dlmlock_master */
6714d8e8
KH		 1149 assert = 1;
1150 sleep = 0;
1151 }
1152 /* if voting is done, but we have not received
1153 * an assert master yet, we must sleep */
1154 }
1155 }
1156
1157 spin_unlock(&mle->spinlock);
1158
1159 /* sleep if we haven't finished voting yet */
1160 if (sleep) {
1161 unsigned long timeo = msecs_to_jiffies(DLM_MASTERY_TIMEOUT_MS);
1162
1163 /*
1164 if (atomic_read(&mle->mle_refs.refcount) < 2)
1165 mlog(ML_ERROR, "mle (%p) refs=%d, name=%.*s\n", mle,
1166 atomic_read(&mle->mle_refs.refcount),
1167 res->lockname.len, res->lockname.name);
1168 */
1169 atomic_set(&mle->woken, 0);
1170 (void)wait_event_timeout(mle->wq,
1171 (atomic_read(&mle->woken) == 1),
1172 timeo);
1173 if (res->owner == O2NM_MAX_NODES) {
ba2bf218
KH		 1174 mlog(0, "%s:%.*s: waiting again\n", dlm->name,
1175 res->lockname.len, res->lockname.name);
6714d8e8
KH		 1176 goto recheck;
1177 }
1178 mlog(0, "done waiting, master is %u\n", res->owner);
1179 ret = 0;
1180 goto leave;
1181 }
1182
1183 ret = 0; /* done */
1184 if (assert) {
1185 m = dlm->node_num;
1186 mlog(0, "about to master %.*s here, this=%u\n",
1187 res->lockname.len, res->lockname.name, m);
ba2bf218 1188 ret = dlm_do_assert_master(dlm, res, mle->vote_map, 0);
6714d8e8
KH		 1189 if (ret) {
1190 /* This is a failure in the network path,
1191 * not in the response to the assert_master
1192 * (any nonzero response is a BUG on this node).
1193 * Most likely a socket just got disconnected
1194 * due to node death. */
1195 mlog_errno(ret);
1196 }
1197 /* no longer need to restart lock mastery.
1198 * all living nodes have been contacted. */
1199 ret = 0;
1200 }
1201
1202 /* set the lockres owner */
1203 spin_lock(&res->spinlock);
ba2bf218
KH		 1204 /* mastery reference obtained either during
1205 * assert_master_handler or in get_lock_resource */
6714d8e8
KH		 1206 dlm_change_lockres_owner(dlm, res, m);
1207 spin_unlock(&res->spinlock);
1208
1209leave:
1210 return ret;
1211}
1212
1213struct dlm_bitmap_diff_iter
1214{
1215 int curnode;
1216 unsigned long *orig_bm;
1217 unsigned long *cur_bm;
1218 unsigned long diff_bm[BITS_TO_LONGS(O2NM_MAX_NODES)];
1219};
1220
1221enum dlm_node_state_change
1222{
1223 NODE_DOWN = -1,
1224 NODE_NO_CHANGE = 0,
1225 NODE_UP
1226};
1227
1228static void dlm_bitmap_diff_iter_init(struct dlm_bitmap_diff_iter *iter,
1229 unsigned long *orig_bm,
1230 unsigned long *cur_bm)
1231{
1232 unsigned long p1, p2;
1233 int i;
1234
1235 iter->curnode = -1;
1236 iter->orig_bm = orig_bm;
1237 iter->cur_bm = cur_bm;
1238
1239 for (i = 0; i < BITS_TO_LONGS(O2NM_MAX_NODES); i++) {
1240 p1 = *(iter->orig_bm + i);
1241 p2 = *(iter->cur_bm + i);
1242 iter->diff_bm[i] = (p1 & ~p2) | (p2 & ~p1);
1243 }
1244}
1245
1246static int dlm_bitmap_diff_iter_next(struct dlm_bitmap_diff_iter *iter,
1247 enum dlm_node_state_change *state)
1248{
1249 int bit;
1250
1251 if (iter->curnode >= O2NM_MAX_NODES)
1252 return -ENOENT;
1253
1254 bit = find_next_bit(iter->diff_bm, O2NM_MAX_NODES,
1255 iter->curnode+1);
1256 if (bit >= O2NM_MAX_NODES) {
1257 iter->curnode = O2NM_MAX_NODES;
1258 return -ENOENT;
1259 }
1260
1261 /* if it was there in the original then this node died */
1262 if (test_bit(bit, iter->orig_bm))
1263 *state = NODE_DOWN;
1264 else
1265 *state = NODE_UP;
1266
1267 iter->curnode = bit;
1268 return bit;
1269}
1270
1271
1272static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
1273 struct dlm_lock_resource *res,
1274 struct dlm_master_list_entry *mle,
1275 int blocked)
1276{
1277 struct dlm_bitmap_diff_iter bdi;
1278 enum dlm_node_state_change sc;
1279 int node;
1280 int ret = 0;
1281
1282 mlog(0, "something happened such that the "
1283 "master process may need to be restarted!\n");
1284
1285 assert_spin_locked(&mle->spinlock);
1286
1287 dlm_bitmap_diff_iter_init(&bdi, mle->vote_map, mle->node_map);
1288 node = dlm_bitmap_diff_iter_next(&bdi, &sc);
1289 while (node >= 0) {
1290 if (sc == NODE_UP) {
e2faea4c
KH		 1291 /* a node came up. clear any old vote from
1292 * the response map and set it in the vote map
1293 * then restart the mastery. */
1294 mlog(ML_NOTICE, "node %d up while restarting\n", node);
6714d8e8
KH		 1295
1296 /* redo the master request, but only for the new node */
1297 mlog(0, "sending request to new node\n");
1298 clear_bit(node, mle->response_map);
1299 set_bit(node, mle->vote_map);
1300 } else {
1301 mlog(ML_ERROR, "node down! %d\n", node);
6714d8e8
KH		 1302 if (blocked) {
1303 int lowest = find_next_bit(mle->maybe_map,
1304 O2NM_MAX_NODES, 0);
1305
1306 /* act like it was never there */
1307 clear_bit(node, mle->maybe_map);
1308
e7e69eb3
KH		 1309 if (node == lowest) {
1310 mlog(0, "expected master %u died"
1311 " while this node was blocked "
1312 "waiting on it!\n", node);
1313 lowest = find_next_bit(mle->maybe_map,
1314 O2NM_MAX_NODES,
1315 lowest+1);
1316 if (lowest < O2NM_MAX_NODES) {
1317 mlog(0, "%s:%.*s:still "
1318 "blocked. waiting on %u "
1319 "now\n", dlm->name,
1320 res->lockname.len,
1321 res->lockname.name,
1322 lowest);
1323 } else {
1324 /* mle is an MLE_BLOCK, but
1325 * there is now nothing left to
1326 * block on. we need to return
1327 * all the way back out and try
1328 * again with an MLE_MASTER.
1329 * dlm_do_local_recovery_cleanup
1330 * has already run, so the mle
1331 * refcount is ok */
1332 mlog(0, "%s:%.*s: no "
1333 "longer blocking. try to "
1334 "master this here\n",
1335 dlm->name,
1336 res->lockname.len,
1337 res->lockname.name);
1338 mle->type = DLM_MLE_MASTER;
1339 mle->u.res = res;
1340 }
6714d8e8 1341 }
6714d8e8
KH		 1342 }
1343
e7e69eb3
KH		 1344 /* now blank out everything, as if we had never
1345 * contacted anyone */
1346 memset(mle->maybe_map, 0, sizeof(mle->maybe_map));
1347 memset(mle->response_map, 0, sizeof(mle->response_map));
1348 /* reset the vote_map to the current node_map */
1349 memcpy(mle->vote_map, mle->node_map,
1350 sizeof(mle->node_map));
1351 /* put myself into the maybe map */
1352 if (mle->type != DLM_MLE_BLOCK)
1353 set_bit(dlm->node_num, mle->maybe_map);
6714d8e8
KH		 1354 }
1355 ret = -EAGAIN;
6714d8e8
KH		 1356 node = dlm_bitmap_diff_iter_next(&bdi, &sc);
1357 }
1358 return ret;
1359}
1360
1361
1362/*
1363 * DLM_MASTER_REQUEST_MSG
1364 *
1365 * returns: 0 on success,
1366 * -errno on a network error
1367 *
1368 * on error, the caller should assume the target node is "dead"
1369 *
1370 */
1371
ba2bf218
KH		 1372static int dlm_do_master_request(struct dlm_lock_resource *res,
1373 struct dlm_master_list_entry *mle, int to)
6714d8e8
KH		 1374{
1375 struct dlm_ctxt *dlm = mle->dlm;
1376 struct dlm_master_request request;
1377 int ret, response=0, resend;
1378
1379 memset(&request, 0, sizeof(request));
1380 request.node_idx = dlm->node_num;
1381
1382 BUG_ON(mle->type == DLM_MLE_MIGRATION);
1383
1384 if (mle->type != DLM_MLE_MASTER) {
1385 request.namelen = mle->u.name.len;
1386 memcpy(request.name, mle->u.name.name, request.namelen);
1387 } else {
1388 request.namelen = mle->u.res->lockname.len;
1389 memcpy(request.name, mle->u.res->lockname.name,
1390 request.namelen);
1391 }
1392
1393again:
1394 ret = o2net_send_message(DLM_MASTER_REQUEST_MSG, dlm->key, &request,
1395 sizeof(request), to, &response);
1396 if (ret < 0) {
1397 if (ret == -ESRCH) {
1398 /* should never happen */
1399 mlog(ML_ERROR, "TCP stack not ready!\n");
1400 BUG();
1401 } else if (ret == -EINVAL) {
1402 mlog(ML_ERROR, "bad args passed to o2net!\n");
1403 BUG();
1404 } else if (ret == -ENOMEM) {
1405 mlog(ML_ERROR, "out of memory while trying to send "
1406 "network message! retrying\n");
1407 /* this is totally crude */
1408 msleep(50);
1409 goto again;
1410 } else if (!dlm_is_host_down(ret)) {
1411 /* not a network error. bad. */
1412 mlog_errno(ret);
1413 mlog(ML_ERROR, "unhandled error!");
1414 BUG();
1415 }
1416 /* all other errors should be network errors,
1417 * and likely indicate node death */
1418 mlog(ML_ERROR, "link to %d went down!\n", to);
1419 goto out;
1420 }
1421
1422 ret = 0;
1423 resend = 0;
1424 spin_lock(&mle->spinlock);
1425 switch (response) {
1426 case DLM_MASTER_RESP_YES:
1427 set_bit(to, mle->response_map);
1428 mlog(0, "node %u is the master, response=YES\n", to);
ba2bf218
KH		 1429 mlog(0, "%s:%.*s: master node %u now knows I have a "
1430 "reference\n", dlm->name, res->lockname.len,
1431 res->lockname.name, to);
6714d8e8
KH		 1432 mle->master = to;
1433 break;
1434 case DLM_MASTER_RESP_NO:
1435 mlog(0, "node %u not master, response=NO\n", to);
1436 set_bit(to, mle->response_map);
1437 break;
1438 case DLM_MASTER_RESP_MAYBE:
1439 mlog(0, "node %u not master, response=MAYBE\n", to);
1440 set_bit(to, mle->response_map);
1441 set_bit(to, mle->maybe_map);
1442 break;
1443 case DLM_MASTER_RESP_ERROR:
1444 mlog(0, "node %u hit an error, resending\n", to);
1445 resend = 1;
1446 response = 0;
1447 break;
1448 default:
1449 mlog(ML_ERROR, "bad response! %u\n", response);
1450 BUG();
1451 }
1452 spin_unlock(&mle->spinlock);
1453 if (resend) {
1454 /* this is also totally crude */
1455 msleep(50);
1456 goto again;
1457 }
1458
1459out:
1460 return ret;
1461}
1462
1463/*
1464 * locks that can be taken here:
1465 * dlm->spinlock
1466 * res->spinlock
1467 * mle->spinlock
1468 * dlm->master_list
1469 *
1470 * if possible, TRIM THIS DOWN!!!
1471 */
1472int dlm_master_request_handler(struct o2net_msg *msg, u32 len, void *data)
1473{
1474 u8 response = DLM_MASTER_RESP_MAYBE;
1475 struct dlm_ctxt *dlm = data;
9c6510a5 1476 struct dlm_lock_resource *res = NULL;
6714d8e8
KH		 1477 struct dlm_master_request *request = (struct dlm_master_request *) msg->buf;
1478 struct dlm_master_list_entry *mle = NULL, *tmpmle = NULL;
1479 char *name;
a3d33291 1480 unsigned int namelen, hash;
6714d8e8
KH		 1481 int found, ret;
1482 int set_maybe;
9c6510a5 1483 int dispatch_assert = 0;
6714d8e8
KH		 1484
1485 if (!dlm_grab(dlm))
1486 return DLM_MASTER_RESP_NO;
1487
1488 if (!dlm_domain_fully_joined(dlm)) {
1489 response = DLM_MASTER_RESP_NO;
1490 goto send_response;
1491 }
1492
1493 name = request->name;
1494 namelen = request->namelen;
a3d33291 1495 hash = dlm_lockid_hash(name, namelen);
6714d8e8
KH		 1496
1497 if (namelen > DLM_LOCKID_NAME_MAX) {
1498 response = DLM_IVBUFLEN;
1499 goto send_response;
1500 }
1501
1502way_up_top:
1503 spin_lock(&dlm->spinlock);
a3d33291 1504 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
6714d8e8
KH		 1505 if (res) {
1506 spin_unlock(&dlm->spinlock);
1507
1508 /* take care of the easy cases up front */
1509 spin_lock(&res->spinlock);
1510 if (res->state & DLM_LOCK_RES_RECOVERING) {
1511 spin_unlock(&res->spinlock);
1512 mlog(0, "returning DLM_MASTER_RESP_ERROR since res is "
1513 "being recovered\n");
1514 response = DLM_MASTER_RESP_ERROR;
1515 if (mle)
1516 kmem_cache_free(dlm_mle_cache, mle);
1517 goto send_response;
1518 }
1519
1520 if (res->owner == dlm->node_num) {
ba2bf218
KH		 1521 mlog(0, "%s:%.*s: setting bit %u in refmap\n",
1522 dlm->name, namelen, name, request->node_idx);
1523 dlm_lockres_set_refmap_bit(request->node_idx, res);
6714d8e8 1524 spin_unlock(&res->spinlock);
6714d8e8
KH		 1525 response = DLM_MASTER_RESP_YES;
1526 if (mle)
1527 kmem_cache_free(dlm_mle_cache, mle);
1528
1529 /* this node is the owner.
1530 * there is some extra work that needs to
1531 * happen now. the requesting node has
1532 * caused all nodes up to this one to
1533 * create mles. this node now needs to
1534 * go back and clean those up. */
9c6510a5 1535 dispatch_assert = 1;
6714d8e8
KH		 1536 goto send_response;
1537 } else if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1538 spin_unlock(&res->spinlock);
1539 // mlog(0, "node %u is the master\n", res->owner);
1540 response = DLM_MASTER_RESP_NO;
1541 if (mle)
1542 kmem_cache_free(dlm_mle_cache, mle);
1543 goto send_response;
1544 }
1545
1546 /* ok, there is no owner. either this node is
1547 * being blocked, or it is actively trying to
1548 * master this lock. */
1549 if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
1550 mlog(ML_ERROR, "lock with no owner should be "
1551 "in-progress!\n");
1552 BUG();
1553 }
1554
1555 // mlog(0, "lockres is in progress...\n");
1556 spin_lock(&dlm->master_lock);
1557 found = dlm_find_mle(dlm, &tmpmle, name, namelen);
1558 if (!found) {
1559 mlog(ML_ERROR, "no mle found for this lock!\n");
1560 BUG();
1561 }
1562 set_maybe = 1;
1563 spin_lock(&tmpmle->spinlock);
1564 if (tmpmle->type == DLM_MLE_BLOCK) {
1565 // mlog(0, "this node is waiting for "
1566 // "lockres to be mastered\n");
1567 response = DLM_MASTER_RESP_NO;
1568 } else if (tmpmle->type == DLM_MLE_MIGRATION) {
1569 mlog(0, "node %u is master, but trying to migrate to "
1570 "node %u.\n", tmpmle->master, tmpmle->new_master);
1571 if (tmpmle->master == dlm->node_num) {
6714d8e8
KH		 1572 mlog(ML_ERROR, "no owner on lockres, but this "
1573 "node is trying to migrate it to %u?!\n",
1574 tmpmle->new_master);
1575 BUG();
1576 } else {
1577 /* the real master can respond on its own */
1578 response = DLM_MASTER_RESP_NO;
1579 }
1580 } else if (tmpmle->master != DLM_LOCK_RES_OWNER_UNKNOWN) {
1581 set_maybe = 0;
9c6510a5 1582 if (tmpmle->master == dlm->node_num) {
6714d8e8 1583 response = DLM_MASTER_RESP_YES;
9c6510a5
KH		 1584 /* this node will be the owner.
1585 * go back and clean the mles on any
1586 * other nodes */
1587 dispatch_assert = 1;
ba2bf218
KH		 1588 dlm_lockres_set_refmap_bit(request->node_idx, res);
1589 mlog(0, "%s:%.*s: setting bit %u in refmap\n",
1590 dlm->name, namelen, name,
1591 request->node_idx);
9c6510a5 1592 } else
6714d8e8
KH		 1593 response = DLM_MASTER_RESP_NO;
1594 } else {
1595 // mlog(0, "this node is attempting to "
1596 // "master lockres\n");
1597 response = DLM_MASTER_RESP_MAYBE;
1598 }
1599 if (set_maybe)
1600 set_bit(request->node_idx, tmpmle->maybe_map);
1601 spin_unlock(&tmpmle->spinlock);
1602
1603 spin_unlock(&dlm->master_lock);
1604 spin_unlock(&res->spinlock);
1605
1606 /* keep the mle attached to heartbeat events */
1607 dlm_put_mle(tmpmle);
1608 if (mle)
1609 kmem_cache_free(dlm_mle_cache, mle);
1610 goto send_response;
1611 }
1612
1613 /*
1614 * lockres doesn't exist on this node
1615 * if there is an MLE_BLOCK, return NO
1616 * if there is an MLE_MASTER, return MAYBE
1617 * otherwise, add an MLE_BLOCK, return NO
1618 */
1619 spin_lock(&dlm->master_lock);
1620 found = dlm_find_mle(dlm, &tmpmle, name, namelen);
1621 if (!found) {
1622 /* this lockid has never been seen on this node yet */
1623 // mlog(0, "no mle found\n");
1624 if (!mle) {
1625 spin_unlock(&dlm->master_lock);
1626 spin_unlock(&dlm->spinlock);
1627
1628 mle = (struct dlm_master_list_entry *)
ad8100e0 1629 kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
6714d8e8 1630 if (!mle) {
6714d8e8 1631 response = DLM_MASTER_RESP_ERROR;
9c6510a5 1632 mlog_errno(-ENOMEM);
6714d8e8
KH		 1633 goto send_response;
1634 }
6714d8e8
KH		 1635 goto way_up_top;
1636 }
1637
1638 // mlog(0, "this is second time thru, already allocated, "
1639 // "add the block.\n");
41b8c8a1 1640 dlm_init_mle(mle, DLM_MLE_BLOCK, dlm, NULL, name, namelen);
6714d8e8
KH		 1641 set_bit(request->node_idx, mle->maybe_map);
1642 list_add(&mle->list, &dlm->master_list);
1643 response = DLM_MASTER_RESP_NO;
1644 } else {
1645 // mlog(0, "mle was found\n");
1646 set_maybe = 1;
1647 spin_lock(&tmpmle->spinlock);
9c6510a5
KH		 1648 if (tmpmle->master == dlm->node_num) {
1649 mlog(ML_ERROR, "no lockres, but an mle with this node as master!\n");
1650 BUG();
1651 }
6714d8e8
KH		 1652 if (tmpmle->type == DLM_MLE_BLOCK)
1653 response = DLM_MASTER_RESP_NO;
1654 else if (tmpmle->type == DLM_MLE_MIGRATION) {
1655 mlog(0, "migration mle was found (%u->%u)\n",
1656 tmpmle->master, tmpmle->new_master);
6714d8e8
KH		 1657 /* real master can respond on its own */
1658 response = DLM_MASTER_RESP_NO;
9c6510a5
KH		 1659 } else
1660 response = DLM_MASTER_RESP_MAYBE;
6714d8e8
KH		 1661 if (set_maybe)
1662 set_bit(request->node_idx, tmpmle->maybe_map);
1663 spin_unlock(&tmpmle->spinlock);
1664 }
1665 spin_unlock(&dlm->master_lock);
1666 spin_unlock(&dlm->spinlock);
1667
1668 if (found) {
1669 /* keep the mle attached to heartbeat events */
1670 dlm_put_mle(tmpmle);
1671 }
1672send_response:
9c6510a5
KH		 1673
1674 if (dispatch_assert) {
1675 if (response != DLM_MASTER_RESP_YES)
1676 mlog(ML_ERROR, "invalid response %d\n", response);
1677 if (!res) {
1678 mlog(ML_ERROR, "bad lockres while trying to assert!\n");
1679 BUG();
1680 }
1681 mlog(0, "%u is the owner of %.*s, cleaning everyone else\n",
1682 dlm->node_num, res->lockname.len, res->lockname.name);
1683 ret = dlm_dispatch_assert_master(dlm, res, 0, request->node_idx,
1684 DLM_ASSERT_MASTER_MLE_CLEANUP);
1685 if (ret < 0) {
1686 mlog(ML_ERROR, "failed to dispatch assert master work\n");
1687 response = DLM_MASTER_RESP_ERROR;
1688 }
1689 }
1690
6714d8e8
KH		 1691 dlm_put(dlm);
1692 return response;
1693}
1694
1695/*
1696 * DLM_ASSERT_MASTER_MSG
1697 */
1698
1699
1700/*
1701 * NOTE: this can be used for debugging
1702 * can periodically run all locks owned by this node
1703 * and re-assert across the cluster...
1704 */
ba2bf218
KH		 1705int dlm_do_assert_master(struct dlm_ctxt *dlm,
1706 struct dlm_lock_resource *res,
1707 void *nodemap, u32 flags)
6714d8e8
KH		 1708{
1709 struct dlm_assert_master assert;
1710 int to, tmpret;
1711 struct dlm_node_iter iter;
1712 int ret = 0;
9c6510a5 1713 int reassert;
ba2bf218
KH		 1714 const char *lockname = res->lockname.name;
1715 unsigned int namelen = res->lockname.len;
6714d8e8
KH		 1716
1717 BUG_ON(namelen > O2NM_MAX_NAME_LEN);
9c6510a5
KH		 1718again:
1719 reassert = 0;
6714d8e8
KH		 1720
1721 /* note that if this nodemap is empty, it returns 0 */
1722 dlm_node_iter_init(nodemap, &iter);
1723 while ((to = dlm_node_iter_next(&iter)) >= 0) {
1724 int r = 0;
a9ee4c8a
KH		 1725 struct dlm_master_list_entry *mle = NULL;
1726
6714d8e8
KH		 1727 mlog(0, "sending assert master to %d (%.*s)\n", to,
1728 namelen, lockname);
1729 memset(&assert, 0, sizeof(assert));
1730 assert.node_idx = dlm->node_num;
1731 assert.namelen = namelen;
1732 memcpy(assert.name, lockname, namelen);
1733 assert.flags = cpu_to_be32(flags);
1734
1735 tmpret = o2net_send_message(DLM_ASSERT_MASTER_MSG, dlm->key,
1736 &assert, sizeof(assert), to, &r);
1737 if (tmpret < 0) {
3b3b84a8 1738 mlog(0, "assert_master returned %d!\n", tmpret);
6714d8e8 1739 if (!dlm_is_host_down(tmpret)) {
3b3b84a8 1740 mlog(ML_ERROR, "unhandled error=%d!\n", tmpret);
6714d8e8
KH		 1741 BUG();
1742 }
1743 /* a node died. finish out the rest of the nodes. */
3b3b84a8 1744 mlog(0, "link to %d went down!\n", to);
6714d8e8
KH		 1745 /* any nonzero status return will do */
1746 ret = tmpret;
ba2bf218 1747 r = 0;
6714d8e8
KH		 1748 } else if (r < 0) {
1749 /* ok, something horribly messed. kill thyself. */
1750 mlog(ML_ERROR,"during assert master of %.*s to %u, "
1751 "got %d.\n", namelen, lockname, to, r);
a9ee4c8a
KH		 1752 spin_lock(&dlm->spinlock);
1753 spin_lock(&dlm->master_lock);
1754 if (dlm_find_mle(dlm, &mle, (char *)lockname,
1755 namelen)) {
1756 dlm_print_one_mle(mle);
1757 __dlm_put_mle(mle);
1758 }
1759 spin_unlock(&dlm->master_lock);
1760 spin_unlock(&dlm->spinlock);
6714d8e8 1761 BUG();
ba2bf218
KH		 1762 }
1763
1764 if (r & DLM_ASSERT_RESPONSE_REASSERT &&
1765 !(r & DLM_ASSERT_RESPONSE_MASTERY_REF)) {
1766 mlog(ML_ERROR, "%.*s: very strange, "
1767 "master MLE but no lockres on %u\n",
1768 namelen, lockname, to);
1769 }
1770
1771 if (r & DLM_ASSERT_RESPONSE_REASSERT) {
9c6510a5
KH		 1772 mlog(0, "%.*s: node %u create mles on other "
1773 "nodes and requests a re-assert\n",
1774 namelen, lockname, to);
1775 reassert = 1;
6714d8e8 1776 }
ba2bf218
KH		 1777 if (r & DLM_ASSERT_RESPONSE_MASTERY_REF) {
1778 mlog(0, "%.*s: node %u has a reference to this "
1779 "lockres, set the bit in the refmap\n",
1780 namelen, lockname, to);
1781 spin_lock(&res->spinlock);
1782 dlm_lockres_set_refmap_bit(to, res);
1783 spin_unlock(&res->spinlock);
1784 }
6714d8e8
KH		 1785 }
1786
9c6510a5
KH		 1787 if (reassert)
1788 goto again;
1789
6714d8e8
KH		 1790 return ret;
1791}
1792
1793/*
1794 * locks that can be taken here:
1795 * dlm->spinlock
1796 * res->spinlock
1797 * mle->spinlock
1798 * dlm->master_list
1799 *
1800 * if possible, TRIM THIS DOWN!!!
1801 */
1802int dlm_assert_master_handler(struct o2net_msg *msg, u32 len, void *data)
1803{
1804 struct dlm_ctxt *dlm = data;
1805 struct dlm_master_list_entry *mle = NULL;
1806 struct dlm_assert_master *assert = (struct dlm_assert_master *)msg->buf;
1807 struct dlm_lock_resource *res = NULL;
1808 char *name;
a3d33291 1809 unsigned int namelen, hash;
6714d8e8 1810 u32 flags;
ba2bf218 1811 int master_request = 0, have_lockres_ref = 0;
9c6510a5 1812 int ret = 0;
6714d8e8
KH		 1813
1814 if (!dlm_grab(dlm))
1815 return 0;
1816
1817 name = assert->name;
1818 namelen = assert->namelen;
a3d33291 1819 hash = dlm_lockid_hash(name, namelen);
6714d8e8
KH		 1820 flags = be32_to_cpu(assert->flags);
1821
1822 if (namelen > DLM_LOCKID_NAME_MAX) {
1823 mlog(ML_ERROR, "Invalid name length!");
1824 goto done;
1825 }
1826
1827 spin_lock(&dlm->spinlock);
1828
1829 if (flags)
1830 mlog(0, "assert_master with flags: %u\n", flags);
1831
1832 /* find the MLE */
1833 spin_lock(&dlm->master_lock);
1834 if (!dlm_find_mle(dlm, &mle, name, namelen)) {
1835 /* not an error, could be master just re-asserting */
1836 mlog(0, "just got an assert_master from %u, but no "
1837 "MLE for it! (%.*s)\n", assert->node_idx,
1838 namelen, name);
1839 } else {
1840 int bit = find_next_bit (mle->maybe_map, O2NM_MAX_NODES, 0);
1841 if (bit >= O2NM_MAX_NODES) {
1842 /* not necessarily an error, though less likely.
1843 * could be master just re-asserting. */
aa852354 1844 mlog(0, "no bits set in the maybe_map, but %u "
6714d8e8
KH		 1845 "is asserting! (%.*s)\n", assert->node_idx,
1846 namelen, name);
1847 } else if (bit != assert->node_idx) {
1848 if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
1849 mlog(0, "master %u was found, %u should "
1850 "back off\n", assert->node_idx, bit);
1851 } else {
1852 /* with the fix for bug 569, a higher node
1853 * number winning the mastery will respond
1854 * YES to mastery requests, but this node
1855 * had no way of knowing. let it pass. */
aa852354 1856 mlog(0, "%u is the lowest node, "
6714d8e8
KH		 1857 "%u is asserting. (%.*s) %u must "
1858 "have begun after %u won.\n", bit,
1859 assert->node_idx, namelen, name, bit,
1860 assert->node_idx);
1861 }
1862 }
2d1a868c
KH		 1863 if (mle->type == DLM_MLE_MIGRATION) {
1864 if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
1865 mlog(0, "%s:%.*s: got cleanup assert"
1866 " from %u for migration\n",
1867 dlm->name, namelen, name,
1868 assert->node_idx);
1869 } else if (!(flags & DLM_ASSERT_MASTER_FINISH_MIGRATION)) {
1870 mlog(0, "%s:%.*s: got unrelated assert"
1871 " from %u for migration, ignoring\n",
1872 dlm->name, namelen, name,
1873 assert->node_idx);
1874 __dlm_put_mle(mle);
1875 spin_unlock(&dlm->master_lock);
1876 spin_unlock(&dlm->spinlock);
1877 goto done;
1878 }
1879 }
6714d8e8
KH		 1880 }
1881 spin_unlock(&dlm->master_lock);
1882
1883 /* ok everything checks out with the MLE
1884 * now check to see if there is a lockres */
a3d33291 1885 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
6714d8e8
KH		 1886 if (res) {
1887 spin_lock(&res->spinlock);
1888 if (res->state & DLM_LOCK_RES_RECOVERING) {
1889 mlog(ML_ERROR, "%u asserting but %.*s is "
1890 "RECOVERING!\n", assert->node_idx, namelen, name);
1891 goto kill;
1892 }
1893 if (!mle) {
dc2ed195
KH		 1894 if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN &&
1895 res->owner != assert->node_idx) {
6714d8e8
KH		 1896 mlog(ML_ERROR, "assert_master from "
1897 "%u, but current owner is "
1898 "%u! (%.*s)\n",
1899 assert->node_idx, res->owner,
1900 namelen, name);
1901 goto kill;
1902 }
1903 } else if (mle->type != DLM_MLE_MIGRATION) {
1904 if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1905 /* owner is just re-asserting */
1906 if (res->owner == assert->node_idx) {
1907 mlog(0, "owner %u re-asserting on "
1908 "lock %.*s\n", assert->node_idx,
1909 namelen, name);
1910 goto ok;
1911 }
1912 mlog(ML_ERROR, "got assert_master from "
1913 "node %u, but %u is the owner! "
1914 "(%.*s)\n", assert->node_idx,
1915 res->owner, namelen, name);
1916 goto kill;
1917 }
1918 if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
1919 mlog(ML_ERROR, "got assert from %u, but lock "
1920 "with no owner should be "
1921 "in-progress! (%.*s)\n",
1922 assert->node_idx,
1923 namelen, name);
1924 goto kill;
1925 }
1926 } else /* mle->type == DLM_MLE_MIGRATION */ {
1927 /* should only be getting an assert from new master */
1928 if (assert->node_idx != mle->new_master) {
1929 mlog(ML_ERROR, "got assert from %u, but "
1930 "new master is %u, and old master "
1931 "was %u (%.*s)\n",
1932 assert->node_idx, mle->new_master,
1933 mle->master, namelen, name);
1934 goto kill;
1935 }
1936
1937 }
1938ok:
1939 spin_unlock(&res->spinlock);
1940 }
1941 spin_unlock(&dlm->spinlock);
1942
1943 // mlog(0, "woo! got an assert_master from node %u!\n",
1944 // assert->node_idx);
1945 if (mle) {
9c6510a5
KH		 1946 int extra_ref = 0;
1947 int nn = -1;
a2bf0477 1948 int rr, err = 0;
6714d8e8
KH		 1949
1950 spin_lock(&mle->spinlock);
9c6510a5
KH		 1951 if (mle->type == DLM_MLE_BLOCK || mle->type == DLM_MLE_MIGRATION)
1952 extra_ref = 1;
1953 else {
1954 /* MASTER mle: if any bits set in the response map
1955 * then the calling node needs to re-assert to clear
1956 * up nodes that this node contacted */
1957 while ((nn = find_next_bit (mle->response_map, O2NM_MAX_NODES,
1958 nn+1)) < O2NM_MAX_NODES) {
1959 if (nn != dlm->node_num && nn != assert->node_idx)
1960 master_request = 1;
1961 }
1962 }
6714d8e8
KH		 1963 mle->master = assert->node_idx;
1964 atomic_set(&mle->woken, 1);
1965 wake_up(&mle->wq);
1966 spin_unlock(&mle->spinlock);
1967
a2bf0477 1968 if (res) {
6714d8e8 1969 spin_lock(&res->spinlock);
a2bf0477
KH		 1970 if (mle->type == DLM_MLE_MIGRATION) {
1971 mlog(0, "finishing off migration of lockres %.*s, "
1972 "from %u to %u\n",
1973 res->lockname.len, res->lockname.name,
1974 dlm->node_num, mle->new_master);
1975 res->state &= ~DLM_LOCK_RES_MIGRATING;
1976 dlm_change_lockres_owner(dlm, res, mle->new_master);
1977 BUG_ON(res->state & DLM_LOCK_RES_DIRTY);
1978 } else {
1979 dlm_change_lockres_owner(dlm, res, mle->master);
1980 }
6714d8e8 1981 spin_unlock(&res->spinlock);
ba2bf218 1982 have_lockres_ref = 1;
6714d8e8 1983 }
a2bf0477
KH		 1984
1985 /* master is known, detach if not already detached.
1986 * ensures that only one assert_master call will happen
1987 * on this mle. */
1988 spin_lock(&dlm->spinlock);
1989 spin_lock(&dlm->master_lock);
1990
1991 rr = atomic_read(&mle->mle_refs.refcount);
1992 if (mle->inuse > 0) {
1993 if (extra_ref && rr < 3)
1994 err = 1;
1995 else if (!extra_ref && rr < 2)
1996 err = 1;
1997 } else {
1998 if (extra_ref && rr < 2)
1999 err = 1;
2000 else if (!extra_ref && rr < 1)
2001 err = 1;
2002 }
2003 if (err) {
2004 mlog(ML_ERROR, "%s:%.*s: got assert master from %u "
2005 "that will mess up this node, refs=%d, extra=%d, "
2006 "inuse=%d\n", dlm->name, namelen, name,
2007 assert->node_idx, rr, extra_ref, mle->inuse);
2008 dlm_print_one_mle(mle);
2009 }
2010 list_del_init(&mle->list);
2011 __dlm_mle_detach_hb_events(dlm, mle);
2012 __dlm_put_mle(mle);
6714d8e8
KH		 2013 if (extra_ref) {
2014 /* the assert master message now balances the extra
2015 * ref given by the master / migration request message.
2016 * if this is the last put, it will be removed
2017 * from the list. */
a2bf0477
KH		 2018 __dlm_put_mle(mle);
2019 }
2020 spin_unlock(&dlm->master_lock);
2021 spin_unlock(&dlm->spinlock);
2022 } else if (res) {
2023 if (res->owner != assert->node_idx) {
2024 mlog(0, "assert_master from %u, but current "
2025 "owner is %u (%.*s), no mle\n", assert->node_idx,
2026 res->owner, namelen, name);
6714d8e8
KH		 2027 }
2028 }
2029
2030done:
9c6510a5 2031 ret = 0;
6714d8e8
KH		 2032 if (res)
2033 dlm_lockres_put(res);
2034 dlm_put(dlm);
9c6510a5
KH		 2035 if (master_request) {
2036 mlog(0, "need to tell master to reassert\n");
ba2bf218
KH		 2037 /* positive. negative would shoot down the node. */
2038 ret |= DLM_ASSERT_RESPONSE_REASSERT;
2039 if (!have_lockres_ref) {
2040 mlog(ML_ERROR, "strange, got assert from %u, MASTER "
2041 "mle present here for %s:%.*s, but no lockres!\n",
2042 assert->node_idx, dlm->name, namelen, name);
2043 }
2044 }
2045 if (have_lockres_ref) {
2046 /* let the master know we have a reference to the lockres */
2047 ret |= DLM_ASSERT_RESPONSE_MASTERY_REF;
2048 mlog(0, "%s:%.*s: got assert from %u, need a ref\n",
2049 dlm->name, namelen, name, assert->node_idx);
9c6510a5
KH		 2050 }
2051 return ret;
6714d8e8
KH		 2052
2053kill:
2054 /* kill the caller! */
a9ee4c8a
KH		 2055 mlog(ML_ERROR, "Bad message received from another node. Dumping state "
2056 "and killing the other node now! This node is OK and can continue.\n");
2057 __dlm_print_one_lock_resource(res);
6714d8e8
KH		 2058 spin_unlock(&res->spinlock);
2059 spin_unlock(&dlm->spinlock);
2060 dlm_lockres_put(res);
6714d8e8
KH		 2061 dlm_put(dlm);
2062 return -EINVAL;
2063}
2064
2065int dlm_dispatch_assert_master(struct dlm_ctxt *dlm,
2066 struct dlm_lock_resource *res,
2067 int ignore_higher, u8 request_from, u32 flags)
2068{
2069 struct dlm_work_item *item;
cd861280 2070 item = kzalloc(sizeof(*item), GFP_NOFS);
6714d8e8
KH		 2071 if (!item)
2072 return -ENOMEM;
2073
2074
2075 /* queue up work for dlm_assert_master_worker */
2076 dlm_grab(dlm); /* get an extra ref for the work item */
2077 dlm_init_work_item(dlm, item, dlm_assert_master_worker, NULL);
2078 item->u.am.lockres = res; /* already have a ref */
2079 /* can optionally ignore node numbers higher than this node */
2080 item->u.am.ignore_higher = ignore_higher;
2081 item->u.am.request_from = request_from;
2082 item->u.am.flags = flags;
2083
9c6510a5
KH		 2084 if (ignore_higher)
2085 mlog(0, "IGNORE HIGHER: %.*s\n", res->lockname.len,
2086 res->lockname.name);
2087
6714d8e8
KH		 2088 spin_lock(&dlm->work_lock);
2089 list_add_tail(&item->list, &dlm->work_list);
2090 spin_unlock(&dlm->work_lock);
2091
3156d267 2092 queue_work(dlm->dlm_worker, &dlm->dispatched_work);
6714d8e8
KH		 2093 return 0;
2094}
2095
2096static void dlm_assert_master_worker(struct dlm_work_item *item, void *data)
2097{
2098 struct dlm_ctxt *dlm = data;
2099 int ret = 0;
2100 struct dlm_lock_resource *res;
2101 unsigned long nodemap[BITS_TO_LONGS(O2NM_MAX_NODES)];
2102 int ignore_higher;
2103 int bit;
2104 u8 request_from;
2105 u32 flags;
2106
2107 dlm = item->dlm;
2108 res = item->u.am.lockres;
2109 ignore_higher = item->u.am.ignore_higher;
2110 request_from = item->u.am.request_from;
2111 flags = item->u.am.flags;
2112
2113 spin_lock(&dlm->spinlock);
2114 memcpy(nodemap, dlm->domain_map, sizeof(nodemap));
2115 spin_unlock(&dlm->spinlock);
2116
2117 clear_bit(dlm->node_num, nodemap);
2118 if (ignore_higher) {
2119 /* if is this just to clear up mles for nodes below
2120 * this node, do not send the message to the original
2121 * caller or any node number higher than this */
2122 clear_bit(request_from, nodemap);
2123 bit = dlm->node_num;
2124 while (1) {
2125 bit = find_next_bit(nodemap, O2NM_MAX_NODES,
2126 bit+1);
2127 if (bit >= O2NM_MAX_NODES)
2128 break;
2129 clear_bit(bit, nodemap);
2130 }
2131 }
2132
36407488
KH		 2133 /*
2134 * If we're migrating this lock to someone else, we are no
2135 * longer allowed to assert out own mastery. OTOH, we need to
2136 * prevent migration from starting while we're still asserting
2137 * our dominance. The reserved ast delays migration.
2138 */
2139 spin_lock(&res->spinlock);
2140 if (res->state & DLM_LOCK_RES_MIGRATING) {
2141 mlog(0, "Someone asked us to assert mastery, but we're "
2142 "in the middle of migration. Skipping assert, "
2143 "the new master will handle that.\n");
2144 spin_unlock(&res->spinlock);
2145 goto put;
2146 } else
2147 __dlm_lockres_reserve_ast(res);
2148 spin_unlock(&res->spinlock);
2149
6714d8e8
KH		 2150 /* this call now finishes out the nodemap
2151 * even if one or more nodes die */
2152 mlog(0, "worker about to master %.*s here, this=%u\n",
2153 res->lockname.len, res->lockname.name, dlm->node_num);
ba2bf218 2154 ret = dlm_do_assert_master(dlm, res, nodemap, flags);
6714d8e8
KH		 2155 if (ret < 0) {
2156 /* no need to restart, we are done */
3b3b84a8
KH		 2157 if (!dlm_is_host_down(ret))
2158 mlog_errno(ret);
6714d8e8
KH		 2159 }
2160
36407488
KH		 2161 /* Ok, we've asserted ourselves. Let's let migration start. */
2162 dlm_lockres_release_ast(dlm, res);
2163
2164put:
6714d8e8
KH		 2165 dlm_lockres_put(res);
2166
2167 mlog(0, "finished with dlm_assert_master_worker\n");
2168}
2169
c03872f5
KH		 2170/* SPECIAL CASE for the $RECOVERY lock used by the recovery thread.
2171 * We cannot wait for node recovery to complete to begin mastering this
2172 * lockres because this lockres is used to kick off recovery! ;-)
2173 * So, do a pre-check on all living nodes to see if any of those nodes
2174 * think that $RECOVERY is currently mastered by a dead node. If so,
2175 * we wait a short time to allow that node to get notified by its own
2176 * heartbeat stack, then check again. All $RECOVERY lock resources
2177 * mastered by dead nodes are purged when the hearbeat callback is
2178 * fired, so we can know for sure that it is safe to continue once
2179 * the node returns a live node or no node. */
2180static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
2181 struct dlm_lock_resource *res)
2182{
2183 struct dlm_node_iter iter;
2184 int nodenum;
2185 int ret = 0;
2186 u8 master = DLM_LOCK_RES_OWNER_UNKNOWN;
2187
2188 spin_lock(&dlm->spinlock);
2189 dlm_node_iter_init(dlm->domain_map, &iter);
2190 spin_unlock(&dlm->spinlock);
2191
2192 while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
2193 /* do not send to self */
2194 if (nodenum == dlm->node_num)
2195 continue;
2196 ret = dlm_do_master_requery(dlm, res, nodenum, &master);
2197 if (ret < 0) {
2198 mlog_errno(ret);
2199 if (!dlm_is_host_down(ret))
2200 BUG();
2201 /* host is down, so answer for that node would be
2202 * DLM_LOCK_RES_OWNER_UNKNOWN. continue. */
f42a100b 2203 ret = 0;
c03872f5
KH		 2204 }
2205
2206 if (master != DLM_LOCK_RES_OWNER_UNKNOWN) {
2207 /* check to see if this master is in the recovery map */
2208 spin_lock(&dlm->spinlock);
2209 if (test_bit(master, dlm->recovery_map)) {
2210 mlog(ML_NOTICE, "%s: node %u has not seen "
2211 "node %u go down yet, and thinks the "
2212 "dead node is mastering the recovery "
2213 "lock. must wait.\n", dlm->name,
2214 nodenum, master);
2215 ret = -EAGAIN;
2216 }
2217 spin_unlock(&dlm->spinlock);
2218 mlog(0, "%s: reco lock master is %u\n", dlm->name,
2219 master);
2220 break;
2221 }
2222 }
2223 return ret;
2224}
2225
ba2bf218
KH		 2226/*
2227 * DLM_DEREF_LOCKRES_MSG
2228 */
2229
2230int dlm_drop_lockres_ref(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
2231{
2232 struct dlm_deref_lockres deref;
2233 int ret = 0, r;
2234 const char *lockname;
2235 unsigned int namelen;
2236
2237 lockname = res->lockname.name;
2238 namelen = res->lockname.len;
2239 BUG_ON(namelen > O2NM_MAX_NAME_LEN);
2240
2241 mlog(0, "%s:%.*s: sending deref to %d\n",
2242 dlm->name, namelen, lockname, res->owner);
2243 memset(&deref, 0, sizeof(deref));
2244 deref.node_idx = dlm->node_num;
2245 deref.namelen = namelen;
2246 memcpy(deref.name, lockname, namelen);
2247
2248 ret = o2net_send_message(DLM_DEREF_LOCKRES_MSG, dlm->key,
2249 &deref, sizeof(deref), res->owner, &r);
2250 if (ret < 0)
2251 mlog_errno(ret);
2252 else if (r < 0) {
2253 /* BAD. other node says I did not have a ref. */
2254 mlog(ML_ERROR,"while dropping ref on %s:%.*s "
2255 "(master=%u) got %d.\n", dlm->name, namelen,
2256 lockname, res->owner, r);
2257 dlm_print_one_lock_resource(res);
2258 BUG();
2259 }
2260 return ret;
2261}
2262
2263int dlm_deref_lockres_handler(struct o2net_msg *msg, u32 len, void *data)
2264{
2265 struct dlm_ctxt *dlm = data;
2266 struct dlm_deref_lockres *deref = (struct dlm_deref_lockres *)msg->buf;
2267 struct dlm_lock_resource *res = NULL;
2268 char *name;
2269 unsigned int namelen;
2270 int ret = -EINVAL;
2271 u8 node;
2272 unsigned int hash;
2273
2274 if (!dlm_grab(dlm))
2275 return 0;
2276
2277 name = deref->name;
2278 namelen = deref->namelen;
2279 node = deref->node_idx;
2280
2281 if (namelen > DLM_LOCKID_NAME_MAX) {
2282 mlog(ML_ERROR, "Invalid name length!");
2283 goto done;
2284 }
2285 if (deref->node_idx >= O2NM_MAX_NODES) {
2286 mlog(ML_ERROR, "Invalid node number: %u\n", node);
2287 goto done;
2288 }
2289
2290 hash = dlm_lockid_hash(name, namelen);
2291
2292 spin_lock(&dlm->spinlock);
2293 res = __dlm_lookup_lockres_full(dlm, name, namelen, hash);
2294 if (!res) {
2295 spin_unlock(&dlm->spinlock);
2296 mlog(ML_ERROR, "%s:%.*s: bad lockres name\n",
2297 dlm->name, namelen, name);
2298 goto done;
2299 }
2300 spin_unlock(&dlm->spinlock);
2301
2302 spin_lock(&res->spinlock);
2303 BUG_ON(res->state & DLM_LOCK_RES_DROPPING_REF);
2304 if (test_bit(node, res->refmap)) {
2305 ret = 0;
2306 dlm_lockres_clear_refmap_bit(node, res);
2307 } else {
2308 mlog(ML_ERROR, "%s:%.*s: node %u trying to drop ref "
2309 "but it is already dropped!\n", dlm->name, namelen,
2310 name, node);
2311 __dlm_print_one_lock_resource(res);
2312 }
2313 spin_unlock(&res->spinlock);
2314
2315 if (!ret)
2316 dlm_lockres_calc_usage(dlm, res);
2317done:
2318 if (res)
2319 dlm_lockres_put(res);
2320 dlm_put(dlm);
2321 return ret;
2322}
2323
6714d8e8
KH		 2324
2325/*
2326 * DLM_MIGRATE_LOCKRES
2327 */
2328
2329
2330int dlm_migrate_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
2331 u8 target)
2332{
2333 struct dlm_master_list_entry *mle = NULL;
2334 struct dlm_master_list_entry *oldmle = NULL;
2335 struct dlm_migratable_lockres *mres = NULL;
2336 int ret = -EINVAL;
2337 const char *name;
2338 unsigned int namelen;
2339 int mle_added = 0;
2340 struct list_head *queue, *iter;
2341 int i;
2342 struct dlm_lock *lock;
2343 int empty = 1;
2344
2345 if (!dlm_grab(dlm))
2346 return -EINVAL;
2347
2348 name = res->lockname.name;
2349 namelen = res->lockname.len;
2350
2351 mlog(0, "migrating %.*s to %u\n", namelen, name, target);
2352
2353 /*
2354 * ensure this lockres is a proper candidate for migration
2355 */
2356 spin_lock(&res->spinlock);
2357 if (res->owner == DLM_LOCK_RES_OWNER_UNKNOWN) {
2358 mlog(0, "cannot migrate lockres with unknown owner!\n");
2359 spin_unlock(&res->spinlock);
2360 goto leave;
2361 }
2362 if (res->owner != dlm->node_num) {
2363 mlog(0, "cannot migrate lockres this node doesn't own!\n");
2364 spin_unlock(&res->spinlock);
2365 goto leave;
2366 }
2367 mlog(0, "checking queues...\n");
2368 queue = &res->granted;
2369 for (i=0; i<3; i++) {
2370 list_for_each(iter, queue) {
2371 lock = list_entry (iter, struct dlm_lock, list);
2372 empty = 0;
2373 if (lock->ml.node == dlm->node_num) {
2374 mlog(0, "found a lock owned by this node "
2375 "still on the %s queue! will not "
2376 "migrate this lockres\n",
2377 i==0 ? "granted" :
2378 (i==1 ? "converting" : "blocked"));
2379 spin_unlock(&res->spinlock);
2380 ret = -ENOTEMPTY;
2381 goto leave;
2382 }
2383 }
2384 queue++;
2385 }
2386 mlog(0, "all locks on this lockres are nonlocal. continuing\n");
2387 spin_unlock(&res->spinlock);
2388
2389 /* no work to do */
2390 if (empty) {
2391 mlog(0, "no locks were found on this lockres! done!\n");
2392 ret = 0;
2393 goto leave;
2394 }
2395
2396 /*
2397 * preallocate up front
2398 * if this fails, abort
2399 */
2400
2401 ret = -ENOMEM;
ad8100e0 2402 mres = (struct dlm_migratable_lockres *) __get_free_page(GFP_NOFS);
6714d8e8
KH		 2403 if (!mres) {
2404 mlog_errno(ret);
2405 goto leave;
2406 }
2407
2408 mle = (struct dlm_master_list_entry *) kmem_cache_alloc(dlm_mle_cache,
ad8100e0 2409 GFP_NOFS);
6714d8e8
KH		 2410 if (!mle) {
2411 mlog_errno(ret);
2412 goto leave;
2413 }
2414 ret = 0;
2415
2416 /*
2417 * find a node to migrate the lockres to
2418 */
2419
2420 mlog(0, "picking a migration node\n");
2421 spin_lock(&dlm->spinlock);
2422 /* pick a new node */
2423 if (!test_bit(target, dlm->domain_map) ||
2424 target >= O2NM_MAX_NODES) {
2425 target = dlm_pick_migration_target(dlm, res);
2426 }
2427 mlog(0, "node %u chosen for migration\n", target);
2428
2429 if (target >= O2NM_MAX_NODES ||
2430 !test_bit(target, dlm->domain_map)) {
2431 /* target chosen is not alive */
2432 ret = -EINVAL;
2433 }
2434
2435 if (ret) {
2436 spin_unlock(&dlm->spinlock);
2437 goto fail;
2438 }
2439
2440 mlog(0, "continuing with target = %u\n", target);
2441
2442 /*
2443 * clear any existing master requests and
2444 * add the migration mle to the list
2445 */
2446 spin_lock(&dlm->master_lock);
2447 ret = dlm_add_migration_mle(dlm, res, mle, &oldmle, name,
2448 namelen, target, dlm->node_num);
2449 spin_unlock(&dlm->master_lock);
2450 spin_unlock(&dlm->spinlock);
2451
2452 if (ret == -EEXIST) {
2453 mlog(0, "another process is already migrating it\n");
2454 goto fail;
2455 }
2456 mle_added = 1;
2457
2458 /*
2459 * set the MIGRATING flag and flush asts
2460 * if we fail after this we need to re-dirty the lockres
2461 */
2462 if (dlm_mark_lockres_migrating(dlm, res, target) < 0) {
2463 mlog(ML_ERROR, "tried to migrate %.*s to %u, but "
2464 "the target went down.\n", res->lockname.len,
2465 res->lockname.name, target);
2466 spin_lock(&res->spinlock);
2467 res->state &= ~DLM_LOCK_RES_MIGRATING;
2468 spin_unlock(&res->spinlock);
2469 ret = -EINVAL;
2470 }
2471
2472fail:
2473 if (oldmle) {
2474 /* master is known, detach if not already detached */
2475 dlm_mle_detach_hb_events(dlm, oldmle);
2476 dlm_put_mle(oldmle);
2477 }
2478
2479 if (ret < 0) {
2480 if (mle_added) {
2481 dlm_mle_detach_hb_events(dlm, mle);
2482 dlm_put_mle(mle);
2483 } else if (mle) {
2484 kmem_cache_free(dlm_mle_cache, mle);
2485 }
2486 goto leave;
2487 }
2488
2489 /*
2490 * at this point, we have a migration target, an mle
2491 * in the master list, and the MIGRATING flag set on
2492 * the lockres
2493 */
2494
2495
2496 /* get an extra reference on the mle.
2497 * otherwise the assert_master from the new
2498 * master will destroy this.
2499 * also, make sure that all callers of dlm_get_mle
2500 * take both dlm->spinlock and dlm->master_lock */
2501 spin_lock(&dlm->spinlock);
2502 spin_lock(&dlm->master_lock);
a2bf0477 2503 dlm_get_mle_inuse(mle);
6714d8e8
KH		 2504 spin_unlock(&dlm->master_lock);
2505 spin_unlock(&dlm->spinlock);
2506
2507 /* notify new node and send all lock state */
2508 /* call send_one_lockres with migration flag.
2509 * this serves as notice to the target node that a
2510 * migration is starting. */
2511 ret = dlm_send_one_lockres(dlm, res, mres, target,
2512 DLM_MRES_MIGRATION);
2513
2514 if (ret < 0) {
2515 mlog(0, "migration to node %u failed with %d\n",
2516 target, ret);
2517 /* migration failed, detach and clean up mle */
2518 dlm_mle_detach_hb_events(dlm, mle);
2519 dlm_put_mle(mle);
a2bf0477
KH		 2520 dlm_put_mle_inuse(mle);
2521 spin_lock(&res->spinlock);
2522 res->state &= ~DLM_LOCK_RES_MIGRATING;
2523 spin_unlock(&res->spinlock);
6714d8e8
KH		 2524 goto leave;
2525 }
2526
2527 /* at this point, the target sends a message to all nodes,
2528 * (using dlm_do_migrate_request). this node is skipped since
2529 * we had to put an mle in the list to begin the process. this
2530 * node now waits for target to do an assert master. this node
2531 * will be the last one notified, ensuring that the migration
2532 * is complete everywhere. if the target dies while this is
2533 * going on, some nodes could potentially see the target as the
2534 * master, so it is important that my recovery finds the migration
2535 * mle and sets the master to UNKNONWN. */
2536
2537
2538 /* wait for new node to assert master */
2539 while (1) {
2540 ret = wait_event_interruptible_timeout(mle->wq,
2541 (atomic_read(&mle->woken) == 1),
2542 msecs_to_jiffies(5000));
2543
2544 if (ret >= 0) {
2545 if (atomic_read(&mle->woken) == 1 ||
2546 res->owner == target)
2547 break;
2548
2549 mlog(0, "timed out during migration\n");
e2faea4c
KH		 2550 /* avoid hang during shutdown when migrating lockres
2551 * to a node which also goes down */
2552 if (dlm_is_node_dead(dlm, target)) {
aa852354
KH		 2553 mlog(0, "%s:%.*s: expected migration "
2554 "target %u is no longer up, restarting\n",
e2faea4c
KH		 2555 dlm->name, res->lockname.len,
2556 res->lockname.name, target);
2557 ret = -ERESTARTSYS;
2558 }
6714d8e8
KH		 2559 }
2560 if (ret == -ERESTARTSYS) {
2561 /* migration failed, detach and clean up mle */
2562 dlm_mle_detach_hb_events(dlm, mle);
2563 dlm_put_mle(mle);
a2bf0477
KH		 2564 dlm_put_mle_inuse(mle);
2565 spin_lock(&res->spinlock);
2566 res->state &= ~DLM_LOCK_RES_MIGRATING;
2567 spin_unlock(&res->spinlock);
6714d8e8
KH		 2568 goto leave;
2569 }
2570 /* TODO: if node died: stop, clean up, return error */
2571 }
2572
2573 /* all done, set the owner, clear the flag */
2574 spin_lock(&res->spinlock);
2575 dlm_set_lockres_owner(dlm, res, target);
2576 res->state &= ~DLM_LOCK_RES_MIGRATING;
2577 dlm_remove_nonlocal_locks(dlm, res);
2578 spin_unlock(&res->spinlock);
2579 wake_up(&res->wq);
2580
2581 /* master is known, detach if not already detached */
2582 dlm_mle_detach_hb_events(dlm, mle);
a2bf0477 2583 dlm_put_mle_inuse(mle);
6714d8e8
KH		 2584 ret = 0;
2585
2586 dlm_lockres_calc_usage(dlm, res);
2587
2588leave:
2589 /* re-dirty the lockres if we failed */
2590 if (ret < 0)
2591 dlm_kick_thread(dlm, res);
2592
2593 /* TODO: cleanup */
2594 if (mres)
2595 free_page((unsigned long)mres);
2596
2597 dlm_put(dlm);
2598
2599 mlog(0, "returning %d\n", ret);
2600 return ret;
2601}
6714d8e8 2602
ba2bf218
KH		 2603#define DLM_MIGRATION_RETRY_MS 100
2604
2605/* Should be called only after beginning the domain leave process.
2606 * There should not be any remaining locks on nonlocal lock resources,
2607 * and there should be no local locks left on locally mastered resources.
2608 *
2609 * Called with the dlm spinlock held, may drop it to do migration, but
2610 * will re-acquire before exit.
2611 *
2612 * Returns: 1 if dlm->spinlock was dropped/retaken, 0 if never dropped */
2613int dlm_empty_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
2614{
2615 int ret;
2616 int lock_dropped = 0;
2617
2618 if (res->owner != dlm->node_num) {
2619 if (!__dlm_lockres_unused(res)) {
2620 mlog(ML_ERROR, "%s:%.*s: this node is not master, "
2621 "trying to free this but locks remain\n",
2622 dlm->name, res->lockname.len, res->lockname.name);
2623 }
2624 goto leave;
2625 }
2626
2627 /* Wheee! Migrate lockres here! Will sleep so drop spinlock. */
2628 spin_unlock(&dlm->spinlock);
2629 lock_dropped = 1;
2630 while (1) {
2631 ret = dlm_migrate_lockres(dlm, res, O2NM_MAX_NODES);
2632 if (ret >= 0)
2633 break;
2634 if (ret == -ENOTEMPTY) {
2635 mlog(ML_ERROR, "lockres %.*s still has local locks!\n",
2636 res->lockname.len, res->lockname.name);
2637 BUG();
2638 }
2639
2640 mlog(0, "lockres %.*s: migrate failed, "
2641 "retrying\n", res->lockname.len,
2642 res->lockname.name);
2643 msleep(DLM_MIGRATION_RETRY_MS);
2644 }
2645 spin_lock(&dlm->spinlock);
2646leave:
2647 return lock_dropped;
2648}
2649
6714d8e8
KH		 2650int dlm_lock_basts_flushed(struct dlm_ctxt *dlm, struct dlm_lock *lock)
2651{
2652 int ret;
2653 spin_lock(&dlm->ast_lock);
2654 spin_lock(&lock->spinlock);
2655 ret = (list_empty(&lock->bast_list) && !lock->bast_pending);
2656 spin_unlock(&lock->spinlock);
2657 spin_unlock(&dlm->ast_lock);
2658 return ret;
2659}
2660
2661static int dlm_migration_can_proceed(struct dlm_ctxt *dlm,
2662 struct dlm_lock_resource *res,
2663 u8 mig_target)
2664{
2665 int can_proceed;
2666 spin_lock(&res->spinlock);
2667 can_proceed = !!(res->state & DLM_LOCK_RES_MIGRATING);
2668 spin_unlock(&res->spinlock);
2669
2670 /* target has died, so make the caller break out of the
2671 * wait_event, but caller must recheck the domain_map */
2672 spin_lock(&dlm->spinlock);
2673 if (!test_bit(mig_target, dlm->domain_map))
2674 can_proceed = 1;
2675 spin_unlock(&dlm->spinlock);
2676 return can_proceed;
2677}
2678
2679int dlm_lockres_is_dirty(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
2680{
2681 int ret;
2682 spin_lock(&res->spinlock);
2683 ret = !!(res->state & DLM_LOCK_RES_DIRTY);
2684 spin_unlock(&res->spinlock);
2685 return ret;
2686}
2687
2688
2689static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
2690 struct dlm_lock_resource *res,
2691 u8 target)
2692{
2693 int ret = 0;
2694
2695 mlog(0, "dlm_mark_lockres_migrating: %.*s, from %u to %u\n",
2696 res->lockname.len, res->lockname.name, dlm->node_num,
2697 target);
2698 /* need to set MIGRATING flag on lockres. this is done by
2699 * ensuring that all asts have been flushed for this lockres. */
2700 spin_lock(&res->spinlock);
2701 BUG_ON(res->migration_pending);
2702 res->migration_pending = 1;
2703 /* strategy is to reserve an extra ast then release
2704 * it below, letting the release do all of the work */
2705 __dlm_lockres_reserve_ast(res);
2706 spin_unlock(&res->spinlock);
2707
2708 /* now flush all the pending asts.. hang out for a bit */
2709 dlm_kick_thread(dlm, res);
2710 wait_event(dlm->ast_wq, !dlm_lockres_is_dirty(dlm, res));
2711 dlm_lockres_release_ast(dlm, res);
2712
2713 mlog(0, "about to wait on migration_wq, dirty=%s\n",
2714 res->state & DLM_LOCK_RES_DIRTY ? "yes" : "no");
2715 /* if the extra ref we just put was the final one, this
2716 * will pass thru immediately. otherwise, we need to wait
2717 * for the last ast to finish. */
2718again:
2719 ret = wait_event_interruptible_timeout(dlm->migration_wq,
2720 dlm_migration_can_proceed(dlm, res, target),
2721 msecs_to_jiffies(1000));
2722 if (ret < 0) {
2723 mlog(0, "woken again: migrating? %s, dead? %s\n",
2724 res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
2725 test_bit(target, dlm->domain_map) ? "no":"yes");
2726 } else {
2727 mlog(0, "all is well: migrating? %s, dead? %s\n",
2728 res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
2729 test_bit(target, dlm->domain_map) ? "no":"yes");
2730 }
2731 if (!dlm_migration_can_proceed(dlm, res, target)) {
2732 mlog(0, "trying again...\n");
2733 goto again;
2734 }
2735
2736 /* did the target go down or die? */
2737 spin_lock(&dlm->spinlock);
2738 if (!test_bit(target, dlm->domain_map)) {
2739 mlog(ML_ERROR, "aha. migration target %u just went down\n",
2740 target);
2741 ret = -EHOSTDOWN;
2742 }
2743 spin_unlock(&dlm->spinlock);
2744
2745 /*
2746 * at this point:
2747 *
2748 * o the DLM_LOCK_RES_MIGRATING flag is set
2749 * o there are no pending asts on this lockres
2750 * o all processes trying to reserve an ast on this
2751 * lockres must wait for the MIGRATING flag to clear
2752 */
2753 return ret;
2754}
2755
2756/* last step in the migration process.
2757 * original master calls this to free all of the dlm_lock
2758 * structures that used to be for other nodes. */
2759static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
2760 struct dlm_lock_resource *res)
2761{
2762 struct list_head *iter, *iter2;
2763 struct list_head *queue = &res->granted;
ba2bf218 2764 int i, bit;
6714d8e8
KH		 2765 struct dlm_lock *lock;
2766
2767 assert_spin_locked(&res->spinlock);
2768
2769 BUG_ON(res->owner == dlm->node_num);
2770
2771 for (i=0; i<3; i++) {
2772 list_for_each_safe(iter, iter2, queue) {
2773 lock = list_entry (iter, struct dlm_lock, list);
2774 if (lock->ml.node != dlm->node_num) {
2775 mlog(0, "putting lock for node %u\n",
2776 lock->ml.node);
2777 /* be extra careful */
2778 BUG_ON(!list_empty(&lock->ast_list));
2779 BUG_ON(!list_empty(&lock->bast_list));
2780 BUG_ON(lock->ast_pending);
2781 BUG_ON(lock->bast_pending);
ba2bf218 2782 dlm_lockres_clear_refmap_bit(lock->ml.node, res);
6714d8e8
KH		 2783 list_del_init(&lock->list);
2784 dlm_lock_put(lock);
2785 }
2786 }
2787 queue++;
2788 }
ba2bf218
KH		 2789 bit = 0;
2790 while (1) {
2791 bit = find_next_bit(res->refmap, O2NM_MAX_NODES, bit);
2792 if (bit >= O2NM_MAX_NODES)
2793 break;
2794 /* do not clear the local node reference, if there is a
2795 * process holding this, let it drop the ref itself */
2796 if (bit != dlm->node_num) {
2797 mlog(0, "%s:%.*s: node %u had a ref to this "
2798 "migrating lockres, clearing\n", dlm->name,
2799 res->lockname.len, res->lockname.name, bit);
2800 dlm_lockres_clear_refmap_bit(bit, res);
2801 }
2802 bit++;
2803 }
6714d8e8
KH		 2804}
2805
2806/* for now this is not too intelligent. we will
2807 * need stats to make this do the right thing.
2808 * this just finds the first lock on one of the
2809 * queues and uses that node as the target. */
2810static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
2811 struct dlm_lock_resource *res)
2812{
2813 int i;
2814 struct list_head *queue = &res->granted;
2815 struct list_head *iter;
2816 struct dlm_lock *lock;
2817 int nodenum;
2818
2819 assert_spin_locked(&dlm->spinlock);
2820
2821 spin_lock(&res->spinlock);
2822 for (i=0; i<3; i++) {
2823 list_for_each(iter, queue) {
2824 /* up to the caller to make sure this node
2825 * is alive */
2826 lock = list_entry (iter, struct dlm_lock, list);
2827 if (lock->ml.node != dlm->node_num) {
2828 spin_unlock(&res->spinlock);
2829 return lock->ml.node;
2830 }
2831 }
2832 queue++;
2833 }
2834 spin_unlock(&res->spinlock);
2835 mlog(0, "have not found a suitable target yet! checking domain map\n");
2836
2837 /* ok now we're getting desperate. pick anyone alive. */
2838 nodenum = -1;
2839 while (1) {
2840 nodenum = find_next_bit(dlm->domain_map,
2841 O2NM_MAX_NODES, nodenum+1);
2842 mlog(0, "found %d in domain map\n", nodenum);
2843 if (nodenum >= O2NM_MAX_NODES)
2844 break;
2845 if (nodenum != dlm->node_num) {
2846 mlog(0, "picking %d\n", nodenum);
2847 return nodenum;
2848 }
2849 }
2850
2851 mlog(0, "giving up. no master to migrate to\n");
2852 return DLM_LOCK_RES_OWNER_UNKNOWN;
2853}
2854
2855
2856
2857/* this is called by the new master once all lockres
2858 * data has been received */
2859static int dlm_do_migrate_request(struct dlm_ctxt *dlm,
2860 struct dlm_lock_resource *res,
2861 u8 master, u8 new_master,
2862 struct dlm_node_iter *iter)
2863{
2864 struct dlm_migrate_request migrate;
2865 int ret, status = 0;
2866 int nodenum;
2867
2868 memset(&migrate, 0, sizeof(migrate));
2869 migrate.namelen = res->lockname.len;
2870 memcpy(migrate.name, res->lockname.name, migrate.namelen);
2871 migrate.new_master = new_master;
2872 migrate.master = master;
2873
2874 ret = 0;
2875
2876 /* send message to all nodes, except the master and myself */
2877 while ((nodenum = dlm_node_iter_next(iter)) >= 0) {
2878 if (nodenum == master ||
2879 nodenum == new_master)
2880 continue;
2881
2882 ret = o2net_send_message(DLM_MIGRATE_REQUEST_MSG, dlm->key,
2883 &migrate, sizeof(migrate), nodenum,
2884 &status);
2885 if (ret < 0)
2886 mlog_errno(ret);
2887 else if (status < 0) {
2888 mlog(0, "migrate request (node %u) returned %d!\n",
2889 nodenum, status);
2890 ret = status;
ba2bf218
KH		 2891 } else if (status == DLM_MIGRATE_RESPONSE_MASTERY_REF) {
2892 /* during the migration request we short-circuited
2893 * the mastery of the lockres. make sure we have
2894 * a mastery ref for nodenum */
2895 mlog(0, "%s:%.*s: need ref for node %u\n",
2896 dlm->name, res->lockname.len, res->lockname.name,
2897 nodenum);
2898 spin_lock(&res->spinlock);
2899 dlm_lockres_set_refmap_bit(nodenum, res);
2900 spin_unlock(&res->spinlock);
6714d8e8
KH		 2901 }
2902 }
2903
2904 if (ret < 0)
2905 mlog_errno(ret);
2906
2907 mlog(0, "returning ret=%d\n", ret);
2908 return ret;
2909}
2910
2911
2912/* if there is an existing mle for this lockres, we now know who the master is.
2913 * (the one who sent us *this* message) we can clear it up right away.
2914 * since the process that put the mle on the list still has a reference to it,
2915 * we can unhash it now, set the master and wake the process. as a result,
2916 * we will have no mle in the list to start with. now we can add an mle for
2917 * the migration and this should be the only one found for those scanning the
2918 * list. */
2919int dlm_migrate_request_handler(struct o2net_msg *msg, u32 len, void *data)
2920{
2921 struct dlm_ctxt *dlm = data;
2922 struct dlm_lock_resource *res = NULL;
2923 struct dlm_migrate_request *migrate = (struct dlm_migrate_request *) msg->buf;
2924 struct dlm_master_list_entry *mle = NULL, *oldmle = NULL;
2925 const char *name;
a3d33291 2926 unsigned int namelen, hash;
6714d8e8
KH		 2927 int ret = 0;
2928
2929 if (!dlm_grab(dlm))
2930 return -EINVAL;
2931
2932 name = migrate->name;
2933 namelen = migrate->namelen;
a3d33291 2934 hash = dlm_lockid_hash(name, namelen);
6714d8e8
KH		 2935
2936 /* preallocate.. if this fails, abort */
2937 mle = (struct dlm_master_list_entry *) kmem_cache_alloc(dlm_mle_cache,
ad8100e0 2938 GFP_NOFS);
6714d8e8
KH		 2939
2940 if (!mle) {
2941 ret = -ENOMEM;
2942 goto leave;
2943 }
2944
2945 /* check for pre-existing lock */
2946 spin_lock(&dlm->spinlock);
a3d33291 2947 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
6714d8e8
KH		 2948 spin_lock(&dlm->master_lock);
2949
2950 if (res) {
2951 spin_lock(&res->spinlock);
2952 if (res->state & DLM_LOCK_RES_RECOVERING) {
2953 /* if all is working ok, this can only mean that we got
2954 * a migrate request from a node that we now see as
2955 * dead. what can we do here? drop it to the floor? */
2956 spin_unlock(&res->spinlock);
2957 mlog(ML_ERROR, "Got a migrate request, but the "
2958 "lockres is marked as recovering!");
2959 kmem_cache_free(dlm_mle_cache, mle);
2960 ret = -EINVAL; /* need a better solution */
2961 goto unlock;
2962 }
2963 res->state |= DLM_LOCK_RES_MIGRATING;
2964 spin_unlock(&res->spinlock);
2965 }
2966
2967 /* ignore status. only nonzero status would BUG. */
2968 ret = dlm_add_migration_mle(dlm, res, mle, &oldmle,
2969 name, namelen,
2970 migrate->new_master,
2971 migrate->master);
2972
2973unlock:
2974 spin_unlock(&dlm->master_lock);
2975 spin_unlock(&dlm->spinlock);
2976
2977 if (oldmle) {
2978 /* master is known, detach if not already detached */
2979 dlm_mle_detach_hb_events(dlm, oldmle);
2980 dlm_put_mle(oldmle);
2981 }
2982
2983 if (res)
2984 dlm_lockres_put(res);
2985leave:
2986 dlm_put(dlm);
2987 return ret;
2988}
2989
2990/* must be holding dlm->spinlock and dlm->master_lock
2991 * when adding a migration mle, we can clear any other mles
2992 * in the master list because we know with certainty that
2993 * the master is "master". so we remove any old mle from
2994 * the list after setting it's master field, and then add
2995 * the new migration mle. this way we can hold with the rule
2996 * of having only one mle for a given lock name at all times. */
2997static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
2998 struct dlm_lock_resource *res,
2999 struct dlm_master_list_entry *mle,
3000 struct dlm_master_list_entry **oldmle,
3001 const char *name, unsigned int namelen,
3002 u8 new_master, u8 master)
3003{
3004 int found;
3005 int ret = 0;
3006
3007 *oldmle = NULL;
3008
3009 mlog_entry_void();
3010
3011 assert_spin_locked(&dlm->spinlock);
3012 assert_spin_locked(&dlm->master_lock);
3013
3014 /* caller is responsible for any ref taken here on oldmle */
3015 found = dlm_find_mle(dlm, oldmle, (char *)name, namelen);
3016 if (found) {
3017 struct dlm_master_list_entry *tmp = *oldmle;
3018 spin_lock(&tmp->spinlock);
3019 if (tmp->type == DLM_MLE_MIGRATION) {
3020 if (master == dlm->node_num) {
3021 /* ah another process raced me to it */
3022 mlog(0, "tried to migrate %.*s, but some "
3023 "process beat me to it\n",
3024 namelen, name);
3025 ret = -EEXIST;
3026 } else {
3027 /* bad. 2 NODES are trying to migrate! */
3028 mlog(ML_ERROR, "migration error mle: "
3029 "master=%u new_master=%u // request: "
3030 "master=%u new_master=%u // "
3031 "lockres=%.*s\n",
3032 tmp->master, tmp->new_master,
3033 master, new_master,
3034 namelen, name);
3035 BUG();
3036 }
3037 } else {
3038 /* this is essentially what assert_master does */
3039 tmp->master = master;
3040 atomic_set(&tmp->woken, 1);
3041 wake_up(&tmp->wq);
3042 /* remove it from the list so that only one
3043 * mle will be found */
3044 list_del_init(&tmp->list);
ba2bf218
KH		 3045 /* this was obviously WRONG. mle is uninited here. should be tmp. */
3046 __dlm_mle_detach_hb_events(dlm, tmp);
3047 ret = DLM_MIGRATE_RESPONSE_MASTERY_REF;
3048 mlog(0, "%s:%.*s: master=%u, newmaster=%u, "
3049 "telling master to get ref for cleared out mle "
3050 "during migration\n", dlm->name, namelen, name,
3051 master, new_master);
6714d8e8
KH		 3052 }
3053 spin_unlock(&tmp->spinlock);
3054 }
3055
3056 /* now add a migration mle to the tail of the list */
3057 dlm_init_mle(mle, DLM_MLE_MIGRATION, dlm, res, name, namelen);
3058 mle->new_master = new_master;
ba2bf218
KH		 3059 /* the new master will be sending an assert master for this.
3060 * at that point we will get the refmap reference */
6714d8e8
KH		 3061 mle->master = master;
3062 /* do this for consistency with other mle types */
3063 set_bit(new_master, mle->maybe_map);
3064 list_add(&mle->list, &dlm->master_list);
3065
3066 return ret;
3067}
3068
3069
3070void dlm_clean_master_list(struct dlm_ctxt *dlm, u8 dead_node)
3071{
3072 struct list_head *iter, *iter2;
3073 struct dlm_master_list_entry *mle;
3074 struct dlm_lock_resource *res;
a3d33291 3075 unsigned int hash;
6714d8e8
KH		 3076
3077 mlog_entry("dlm=%s, dead node=%u\n", dlm->name, dead_node);
3078top:
3079 assert_spin_locked(&dlm->spinlock);
3080
3081 /* clean the master list */
3082 spin_lock(&dlm->master_lock);
3083 list_for_each_safe(iter, iter2, &dlm->master_list) {
3084 mle = list_entry(iter, struct dlm_master_list_entry, list);
3085
3086 BUG_ON(mle->type != DLM_MLE_BLOCK &&
3087 mle->type != DLM_MLE_MASTER &&
3088 mle->type != DLM_MLE_MIGRATION);
3089
3090 /* MASTER mles are initiated locally. the waiting
3091 * process will notice the node map change
3092 * shortly. let that happen as normal. */
3093 if (mle->type == DLM_MLE_MASTER)
3094 continue;
3095
3096
3097 /* BLOCK mles are initiated by other nodes.
3098 * need to clean up if the dead node would have
3099 * been the master. */
3100 if (mle->type == DLM_MLE_BLOCK) {
3101 int bit;
3102
3103 spin_lock(&mle->spinlock);
3104 bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
3105 if (bit != dead_node) {
3106 mlog(0, "mle found, but dead node %u would "
3107 "not have been master\n", dead_node);
3108 spin_unlock(&mle->spinlock);
3109 } else {
3110 /* must drop the refcount by one since the
3111 * assert_master will never arrive. this
3112 * may result in the mle being unlinked and
3113 * freed, but there may still be a process
3114 * waiting in the dlmlock path which is fine. */
3b3b84a8 3115 mlog(0, "node %u was expected master\n",
6714d8e8
KH		 3116 dead_node);
3117 atomic_set(&mle->woken, 1);
3118 spin_unlock(&mle->spinlock);
3119 wake_up(&mle->wq);
f671c09b
KH		 3120 /* do not need events any longer, so detach
3121 * from heartbeat */
3122 __dlm_mle_detach_hb_events(dlm, mle);
6714d8e8
KH		 3123 __dlm_put_mle(mle);
3124 }
3125 continue;
3126 }
3127
3128 /* everything else is a MIGRATION mle */
3129
3130 /* the rule for MIGRATION mles is that the master
3131 * becomes UNKNOWN if *either* the original or
3132 * the new master dies. all UNKNOWN lockreses
3133 * are sent to whichever node becomes the recovery
3134 * master. the new master is responsible for
3135 * determining if there is still a master for
3136 * this lockres, or if he needs to take over
3137 * mastery. either way, this node should expect
3138 * another message to resolve this. */
3139 if (mle->master != dead_node &&
3140 mle->new_master != dead_node)
3141 continue;
3142
3143 /* if we have reached this point, this mle needs to
3144 * be removed from the list and freed. */
3145
3146 /* remove from the list early. NOTE: unlinking
3147 * list_head while in list_for_each_safe */
da01ad05 3148 __dlm_mle_detach_hb_events(dlm, mle);
6714d8e8
KH		 3149 spin_lock(&mle->spinlock);
3150 list_del_init(&mle->list);
3151 atomic_set(&mle->woken, 1);
3152 spin_unlock(&mle->spinlock);
3153 wake_up(&mle->wq);
3154
aa852354
KH		 3155 mlog(0, "%s: node %u died during migration from "
3156 "%u to %u!\n", dlm->name, dead_node,
6714d8e8
KH		 3157 mle->master, mle->new_master);
3158 /* if there is a lockres associated with this
3159 * mle, find it and set its owner to UNKNOWN */
a3d33291 3160 hash = dlm_lockid_hash(mle->u.name.name, mle->u.name.len);
6714d8e8 3161 res = __dlm_lookup_lockres(dlm, mle->u.name.name,
a3d33291 3162 mle->u.name.len, hash);
6714d8e8
KH		 3163 if (res) {
3164 /* unfortunately if we hit this rare case, our
3165 * lock ordering is messed. we need to drop
3166 * the master lock so that we can take the
3167 * lockres lock, meaning that we will have to
3168 * restart from the head of list. */
3169 spin_unlock(&dlm->master_lock);
3170
3171 /* move lockres onto recovery list */
3172 spin_lock(&res->spinlock);
3173 dlm_set_lockres_owner(dlm, res,
3174 DLM_LOCK_RES_OWNER_UNKNOWN);
3175 dlm_move_lockres_to_recovery_list(dlm, res);
3176 spin_unlock(&res->spinlock);
3177 dlm_lockres_put(res);
3178
f671c09b
KH		 3179 /* about to get rid of mle, detach from heartbeat */
3180 __dlm_mle_detach_hb_events(dlm, mle);
3181
6714d8e8
KH		 3182 /* dump the mle */
3183 spin_lock(&dlm->master_lock);
3184 __dlm_put_mle(mle);
3185 spin_unlock(&dlm->master_lock);
3186
3187 /* restart */
3188 goto top;
3189 }
3190
3191 /* this may be the last reference */
3192 __dlm_put_mle(mle);
3193 }
3194 spin_unlock(&dlm->master_lock);
3195}
3196
3197
3198int dlm_finish_migration(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
3199 u8 old_master)
3200{
3201 struct dlm_node_iter iter;
3202 int ret = 0;
3203
3204 spin_lock(&dlm->spinlock);
3205 dlm_node_iter_init(dlm->domain_map, &iter);
3206 clear_bit(old_master, iter.node_map);
3207 clear_bit(dlm->node_num, iter.node_map);
3208 spin_unlock(&dlm->spinlock);
3209
ba2bf218
KH		 3210 /* ownership of the lockres is changing. account for the
3211 * mastery reference here since old_master will briefly have
3212 * a reference after the migration completes */
3213 spin_lock(&res->spinlock);
3214 dlm_lockres_set_refmap_bit(old_master, res);
3215 spin_unlock(&res->spinlock);
3216
6714d8e8
KH		 3217 mlog(0, "now time to do a migrate request to other nodes\n");
3218 ret = dlm_do_migrate_request(dlm, res, old_master,
3219 dlm->node_num, &iter);
3220 if (ret < 0) {
3221 mlog_errno(ret);
3222 goto leave;
3223 }
3224
3225 mlog(0, "doing assert master of %.*s to all except the original node\n",
3226 res->lockname.len, res->lockname.name);
3227 /* this call now finishes out the nodemap
3228 * even if one or more nodes die */
ba2bf218 3229 ret = dlm_do_assert_master(dlm, res, iter.node_map,
6714d8e8
KH		 3230 DLM_ASSERT_MASTER_FINISH_MIGRATION);
3231 if (ret < 0) {
3232 /* no longer need to retry. all living nodes contacted. */
3233 mlog_errno(ret);
3234 ret = 0;
3235 }
3236
3237 memset(iter.node_map, 0, sizeof(iter.node_map));
3238 set_bit(old_master, iter.node_map);
3239 mlog(0, "doing assert master of %.*s back to %u\n",
3240 res->lockname.len, res->lockname.name, old_master);
ba2bf218 3241 ret = dlm_do_assert_master(dlm, res, iter.node_map,
6714d8e8
KH		 3242 DLM_ASSERT_MASTER_FINISH_MIGRATION);
3243 if (ret < 0) {
3244 mlog(0, "assert master to original master failed "
3245 "with %d.\n", ret);
3246 /* the only nonzero status here would be because of
3247 * a dead original node. we're done. */
3248 ret = 0;
3249 }
3250
3251 /* all done, set the owner, clear the flag */
3252 spin_lock(&res->spinlock);
3253 dlm_set_lockres_owner(dlm, res, dlm->node_num);
3254 res->state &= ~DLM_LOCK_RES_MIGRATING;
3255 spin_unlock(&res->spinlock);
3256 /* re-dirty it on the new master */
3257 dlm_kick_thread(dlm, res);
3258 wake_up(&res->wq);
3259leave:
3260 return ret;
3261}
3262
3263/*
3264 * LOCKRES AST REFCOUNT
3265 * this is integral to migration
3266 */
3267
3268/* for future intent to call an ast, reserve one ahead of time.
3269 * this should be called only after waiting on the lockres
3270 * with dlm_wait_on_lockres, and while still holding the
3271 * spinlock after the call. */
3272void __dlm_lockres_reserve_ast(struct dlm_lock_resource *res)
3273{
3274 assert_spin_locked(&res->spinlock);
3275 if (res->state & DLM_LOCK_RES_MIGRATING) {
3276 __dlm_print_one_lock_resource(res);
3277 }
3278 BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
3279
3280 atomic_inc(&res->asts_reserved);
3281}
3282
3283/*
3284 * used to drop the reserved ast, either because it went unused,
3285 * or because the ast/bast was actually called.
3286 *
3287 * also, if there is a pending migration on this lockres,
3288 * and this was the last pending ast on the lockres,
3289 * atomically set the MIGRATING flag before we drop the lock.
3290 * this is how we ensure that migration can proceed with no
3291 * asts in progress. note that it is ok if the state of the
3292 * queues is such that a lock should be granted in the future
3293 * or that a bast should be fired, because the new master will
3294 * shuffle the lists on this lockres as soon as it is migrated.
3295 */
3296void dlm_lockres_release_ast(struct dlm_ctxt *dlm,
3297 struct dlm_lock_resource *res)
3298{
3299 if (!atomic_dec_and_lock(&res->asts_reserved, &res->spinlock))
3300 return;
3301
3302 if (!res->migration_pending) {
3303 spin_unlock(&res->spinlock);
3304 return;
3305 }
3306
3307 BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
3308 res->migration_pending = 0;
3309 res->state |= DLM_LOCK_RES_MIGRATING;
3310 spin_unlock(&res->spinlock);
3311 wake_up(&res->wq);
3312 wake_up(&dlm->migration_wq);
3313}
Linux 6.x block layer and io_uring tree(s)