projects / linux-2.6-block.git / blame
? search:
summary | shortlog | log | commit | commitdiff | tree
blob | blame (incremental) | history | HEAD
ocfs2: One more hamming code optimization.
[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"
e5a0334c 51#include "dlmdebug.h"
6714d8e8
KH		 52
53#define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_MASTER)
54#include "cluster/masklog.h"
55
6714d8e8
KH		 56static void dlm_mle_node_down(struct dlm_ctxt *dlm,
57 struct dlm_master_list_entry *mle,
58 struct o2nm_node *node,
59 int idx);
60static void dlm_mle_node_up(struct dlm_ctxt *dlm,
61 struct dlm_master_list_entry *mle,
62 struct o2nm_node *node,
63 int idx);
64
65static void dlm_assert_master_worker(struct dlm_work_item *item, void *data);
ba2bf218
KH		 66static int dlm_do_assert_master(struct dlm_ctxt *dlm,
67 struct dlm_lock_resource *res,
68 void *nodemap, u32 flags);
f3f85464 69static void dlm_deref_lockres_worker(struct dlm_work_item *item, void *data);
6714d8e8
KH		 70
71static inline int dlm_mle_equal(struct dlm_ctxt *dlm,
72 struct dlm_master_list_entry *mle,
73 const char *name,
74 unsigned int namelen)
75{
76 struct dlm_lock_resource *res;
77
78 if (dlm != mle->dlm)
79 return 0;
80
81 if (mle->type == DLM_MLE_BLOCK ||
82 mle->type == DLM_MLE_MIGRATION) {
83 if (namelen != mle->u.name.len ||
84 memcmp(name, mle->u.name.name, namelen)!=0)
85 return 0;
86 } else {
87 res = mle->u.res;
88 if (namelen != res->lockname.len ||
89 memcmp(res->lockname.name, name, namelen) != 0)
90 return 0;
91 }
92 return 1;
93}
94
724bdca9
SM		 95static struct kmem_cache *dlm_lockres_cache = NULL;
96static struct kmem_cache *dlm_lockname_cache = NULL;
e18b890b 97static struct kmem_cache *dlm_mle_cache = NULL;
6714d8e8 98
6714d8e8
KH		 99static void dlm_mle_release(struct kref *kref);
100static void dlm_init_mle(struct dlm_master_list_entry *mle,
101 enum dlm_mle_type type,
102 struct dlm_ctxt *dlm,
103 struct dlm_lock_resource *res,
104 const char *name,
105 unsigned int namelen);
106static void dlm_put_mle(struct dlm_master_list_entry *mle);
107static void __dlm_put_mle(struct dlm_master_list_entry *mle);
108static int dlm_find_mle(struct dlm_ctxt *dlm,
109 struct dlm_master_list_entry **mle,
110 char *name, unsigned int namelen);
111
ba2bf218
KH		 112static int dlm_do_master_request(struct dlm_lock_resource *res,
113 struct dlm_master_list_entry *mle, int to);
6714d8e8
KH		 114
115
116static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
117 struct dlm_lock_resource *res,
118 struct dlm_master_list_entry *mle,
119 int *blocked);
120static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
121 struct dlm_lock_resource *res,
122 struct dlm_master_list_entry *mle,
123 int blocked);
124static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
125 struct dlm_lock_resource *res,
126 struct dlm_master_list_entry *mle,
127 struct dlm_master_list_entry **oldmle,
128 const char *name, unsigned int namelen,
129 u8 new_master, u8 master);
130
131static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
132 struct dlm_lock_resource *res);
133static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
134 struct dlm_lock_resource *res);
135static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
136 struct dlm_lock_resource *res,
137 u8 target);
c03872f5
KH		 138static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
139 struct dlm_lock_resource *res);
6714d8e8
KH		 140
141
142int dlm_is_host_down(int errno)
143{
144 switch (errno) {
145 case -EBADF:
146 case -ECONNREFUSED:
147 case -ENOTCONN:
148 case -ECONNRESET:
149 case -EPIPE:
150 case -EHOSTDOWN:
151 case -EHOSTUNREACH:
152 case -ETIMEDOUT:
153 case -ECONNABORTED:
154 case -ENETDOWN:
155 case -ENETUNREACH:
156 case -ENETRESET:
157 case -ESHUTDOWN:
158 case -ENOPROTOOPT:
159 case -EINVAL: /* if returned from our tcp code,
160 this means there is no socket */
161 return 1;
162 }
163 return 0;
164}
165
166
167/*
168 * MASTER LIST FUNCTIONS
169 */
170
171
172/*
173 * regarding master list entries and heartbeat callbacks:
174 *
175 * in order to avoid sleeping and allocation that occurs in
176 * heartbeat, master list entries are simply attached to the
177 * dlm's established heartbeat callbacks. the mle is attached
178 * when it is created, and since the dlm->spinlock is held at
179 * that time, any heartbeat event will be properly discovered
180 * by the mle. the mle needs to be detached from the
181 * dlm->mle_hb_events list as soon as heartbeat events are no
182 * longer useful to the mle, and before the mle is freed.
183 *
184 * as a general rule, heartbeat events are no longer needed by
185 * the mle once an "answer" regarding the lock master has been
186 * received.
187 */
188static inline void __dlm_mle_attach_hb_events(struct dlm_ctxt *dlm,
189 struct dlm_master_list_entry *mle)
190{
191 assert_spin_locked(&dlm->spinlock);
192
193 list_add_tail(&mle->hb_events, &dlm->mle_hb_events);
194}
195
196
197static inline void __dlm_mle_detach_hb_events(struct dlm_ctxt *dlm,
198 struct dlm_master_list_entry *mle)
199{
200 if (!list_empty(&mle->hb_events))
201 list_del_init(&mle->hb_events);
202}
203
204
205static inline void dlm_mle_detach_hb_events(struct dlm_ctxt *dlm,
206 struct dlm_master_list_entry *mle)
207{
208 spin_lock(&dlm->spinlock);
209 __dlm_mle_detach_hb_events(dlm, mle);
210 spin_unlock(&dlm->spinlock);
211}
212
a2bf0477
KH		 213static void dlm_get_mle_inuse(struct dlm_master_list_entry *mle)
214{
215 struct dlm_ctxt *dlm;
216 dlm = mle->dlm;
217
218 assert_spin_locked(&dlm->spinlock);
219 assert_spin_locked(&dlm->master_lock);
220 mle->inuse++;
221 kref_get(&mle->mle_refs);
222}
223
224static void dlm_put_mle_inuse(struct dlm_master_list_entry *mle)
225{
226 struct dlm_ctxt *dlm;
227 dlm = mle->dlm;
228
229 spin_lock(&dlm->spinlock);
230 spin_lock(&dlm->master_lock);
231 mle->inuse--;
232 __dlm_put_mle(mle);
233 spin_unlock(&dlm->master_lock);
234 spin_unlock(&dlm->spinlock);
235
236}
237
6714d8e8
KH		 238/* remove from list and free */
239static void __dlm_put_mle(struct dlm_master_list_entry *mle)
240{
241 struct dlm_ctxt *dlm;
242 dlm = mle->dlm;
243
244 assert_spin_locked(&dlm->spinlock);
245 assert_spin_locked(&dlm->master_lock);
aa852354
KH		 246 if (!atomic_read(&mle->mle_refs.refcount)) {
247 /* this may or may not crash, but who cares.
248 * it's a BUG. */
249 mlog(ML_ERROR, "bad mle: %p\n", mle);
250 dlm_print_one_mle(mle);
251 BUG();
252 } else
253 kref_put(&mle->mle_refs, dlm_mle_release);
6714d8e8
KH		 254}
255
256
257/* must not have any spinlocks coming in */
258static void dlm_put_mle(struct dlm_master_list_entry *mle)
259{
260 struct dlm_ctxt *dlm;
261 dlm = mle->dlm;
262
263 spin_lock(&dlm->spinlock);
264 spin_lock(&dlm->master_lock);
265 __dlm_put_mle(mle);
266 spin_unlock(&dlm->master_lock);
267 spin_unlock(&dlm->spinlock);
268}
269
270static inline void dlm_get_mle(struct dlm_master_list_entry *mle)
271{
272 kref_get(&mle->mle_refs);
273}
274
275static void dlm_init_mle(struct dlm_master_list_entry *mle,
276 enum dlm_mle_type type,
277 struct dlm_ctxt *dlm,
278 struct dlm_lock_resource *res,
279 const char *name,
280 unsigned int namelen)
281{
282 assert_spin_locked(&dlm->spinlock);
283
284 mle->dlm = dlm;
285 mle->type = type;
286 INIT_LIST_HEAD(&mle->list);
287 INIT_LIST_HEAD(&mle->hb_events);
288 memset(mle->maybe_map, 0, sizeof(mle->maybe_map));
289 spin_lock_init(&mle->spinlock);
290 init_waitqueue_head(&mle->wq);
291 atomic_set(&mle->woken, 0);
292 kref_init(&mle->mle_refs);
293 memset(mle->response_map, 0, sizeof(mle->response_map));
294 mle->master = O2NM_MAX_NODES;
295 mle->new_master = O2NM_MAX_NODES;
a2bf0477 296 mle->inuse = 0;
6714d8e8
KH		 297
298 if (mle->type == DLM_MLE_MASTER) {
299 BUG_ON(!res);
300 mle->u.res = res;
301 } else if (mle->type == DLM_MLE_BLOCK) {
302 BUG_ON(!name);
303 memcpy(mle->u.name.name, name, namelen);
304 mle->u.name.len = namelen;
305 } else /* DLM_MLE_MIGRATION */ {
306 BUG_ON(!name);
307 memcpy(mle->u.name.name, name, namelen);
308 mle->u.name.len = namelen;
309 }
310
311 /* copy off the node_map and register hb callbacks on our copy */
312 memcpy(mle->node_map, dlm->domain_map, sizeof(mle->node_map));
313 memcpy(mle->vote_map, dlm->domain_map, sizeof(mle->vote_map));
314 clear_bit(dlm->node_num, mle->vote_map);
315 clear_bit(dlm->node_num, mle->node_map);
316
317 /* attach the mle to the domain node up/down events */
318 __dlm_mle_attach_hb_events(dlm, mle);
319}
320
321
322/* returns 1 if found, 0 if not */
323static int dlm_find_mle(struct dlm_ctxt *dlm,
324 struct dlm_master_list_entry **mle,
325 char *name, unsigned int namelen)
326{
327 struct dlm_master_list_entry *tmpmle;
6714d8e8
KH		 328
329 assert_spin_locked(&dlm->master_lock);
330
800deef3 331 list_for_each_entry(tmpmle, &dlm->master_list, list) {
6714d8e8
KH		 332 if (!dlm_mle_equal(dlm, tmpmle, name, namelen))
333 continue;
334 dlm_get_mle(tmpmle);
335 *mle = tmpmle;
336 return 1;
337 }
338 return 0;
339}
340
341void dlm_hb_event_notify_attached(struct dlm_ctxt *dlm, int idx, int node_up)
342{
343 struct dlm_master_list_entry *mle;
6714d8e8
KH		 344
345 assert_spin_locked(&dlm->spinlock);
346
800deef3 347 list_for_each_entry(mle, &dlm->mle_hb_events, hb_events) {
6714d8e8
KH		 348 if (node_up)
349 dlm_mle_node_up(dlm, mle, NULL, idx);
350 else
351 dlm_mle_node_down(dlm, mle, NULL, idx);
352 }
353}
354
355static void dlm_mle_node_down(struct dlm_ctxt *dlm,
356 struct dlm_master_list_entry *mle,
357 struct o2nm_node *node, int idx)
358{
359 spin_lock(&mle->spinlock);
360
361 if (!test_bit(idx, mle->node_map))
362 mlog(0, "node %u already removed from nodemap!\n", idx);
363 else
364 clear_bit(idx, mle->node_map);
365
366 spin_unlock(&mle->spinlock);
367}
368
369static void dlm_mle_node_up(struct dlm_ctxt *dlm,
370 struct dlm_master_list_entry *mle,
371 struct o2nm_node *node, int idx)
372{
373 spin_lock(&mle->spinlock);
374
375 if (test_bit(idx, mle->node_map))
376 mlog(0, "node %u already in node map!\n", idx);
377 else
378 set_bit(idx, mle->node_map);
379
380 spin_unlock(&mle->spinlock);
381}
382
383
384int dlm_init_mle_cache(void)
385{
12eb0035 386 dlm_mle_cache = kmem_cache_create("o2dlm_mle",
6714d8e8
KH		 387 sizeof(struct dlm_master_list_entry),
388 0, SLAB_HWCACHE_ALIGN,
20c2df83 389 NULL);
6714d8e8
KH		 390 if (dlm_mle_cache == NULL)
391 return -ENOMEM;
392 return 0;
393}
394
395void dlm_destroy_mle_cache(void)
396{
397 if (dlm_mle_cache)
398 kmem_cache_destroy(dlm_mle_cache);
399}
400
401static void dlm_mle_release(struct kref *kref)
402{
403 struct dlm_master_list_entry *mle;
404 struct dlm_ctxt *dlm;
405
406 mlog_entry_void();
407
408 mle = container_of(kref, struct dlm_master_list_entry, mle_refs);
409 dlm = mle->dlm;
410
411 if (mle->type != DLM_MLE_MASTER) {
412 mlog(0, "calling mle_release for %.*s, type %d\n",
413 mle->u.name.len, mle->u.name.name, mle->type);
414 } else {
415 mlog(0, "calling mle_release for %.*s, type %d\n",
416 mle->u.res->lockname.len,
417 mle->u.res->lockname.name, mle->type);
418 }
419 assert_spin_locked(&dlm->spinlock);
420 assert_spin_locked(&dlm->master_lock);
421
422 /* remove from list if not already */
423 if (!list_empty(&mle->list))
424 list_del_init(&mle->list);
425
426 /* detach the mle from the domain node up/down events */
427 __dlm_mle_detach_hb_events(dlm, mle);
428
429 /* NOTE: kfree under spinlock here.
430 * if this is bad, we can move this to a freelist. */
431 kmem_cache_free(dlm_mle_cache, mle);
432}
433
434
435/*
436 * LOCK RESOURCE FUNCTIONS
437 */
438
724bdca9
SM		 439int dlm_init_master_caches(void)
440{
441 dlm_lockres_cache = kmem_cache_create("o2dlm_lockres",
442 sizeof(struct dlm_lock_resource),
443 0, SLAB_HWCACHE_ALIGN, NULL);
444 if (!dlm_lockres_cache)
445 goto bail;
446
447 dlm_lockname_cache = kmem_cache_create("o2dlm_lockname",
448 DLM_LOCKID_NAME_MAX, 0,
449 SLAB_HWCACHE_ALIGN, NULL);
450 if (!dlm_lockname_cache)
451 goto bail;
452
453 return 0;
454bail:
455 dlm_destroy_master_caches();
456 return -ENOMEM;
457}
458
459void dlm_destroy_master_caches(void)
460{
461 if (dlm_lockname_cache)
462 kmem_cache_destroy(dlm_lockname_cache);
463
464 if (dlm_lockres_cache)
465 kmem_cache_destroy(dlm_lockres_cache);
466}
467
6714d8e8
KH		 468static void dlm_set_lockres_owner(struct dlm_ctxt *dlm,
469 struct dlm_lock_resource *res,
470 u8 owner)
471{
472 assert_spin_locked(&res->spinlock);
473
474 mlog_entry("%.*s, %u\n", res->lockname.len, res->lockname.name, owner);
475
476 if (owner == dlm->node_num)
477 atomic_inc(&dlm->local_resources);
478 else if (owner == DLM_LOCK_RES_OWNER_UNKNOWN)
479 atomic_inc(&dlm->unknown_resources);
480 else
481 atomic_inc(&dlm->remote_resources);
482
483 res->owner = owner;
484}
485
486void dlm_change_lockres_owner(struct dlm_ctxt *dlm,
487 struct dlm_lock_resource *res, u8 owner)
488{
489 assert_spin_locked(&res->spinlock);
490
491 if (owner == res->owner)
492 return;
493
494 if (res->owner == dlm->node_num)
495 atomic_dec(&dlm->local_resources);
496 else if (res->owner == DLM_LOCK_RES_OWNER_UNKNOWN)
497 atomic_dec(&dlm->unknown_resources);
498 else
499 atomic_dec(&dlm->remote_resources);
500
501 dlm_set_lockres_owner(dlm, res, owner);
502}
503
504
505static void dlm_lockres_release(struct kref *kref)
506{
507 struct dlm_lock_resource *res;
508
509 res = container_of(kref, struct dlm_lock_resource, refs);
510
511 /* This should not happen -- all lockres' have a name
512 * associated with them at init time. */
513 BUG_ON(!res->lockname.name);
514
515 mlog(0, "destroying lockres %.*s\n", res->lockname.len,
516 res->lockname.name);
517
29576f8b
SM		 518 if (!list_empty(&res->tracking))
519 list_del_init(&res->tracking);
520 else {
521 mlog(ML_ERROR, "Resource %.*s not on the Tracking list\n",
522 res->lockname.len, res->lockname.name);
523 dlm_print_one_lock_resource(res);
524 }
525
a7f90d83
KH		 526 if (!hlist_unhashed(&res->hash_node) ||
527 !list_empty(&res->granted) ||
528 !list_empty(&res->converting) ||
529 !list_empty(&res->blocked) ||
530 !list_empty(&res->dirty) ||
531 !list_empty(&res->recovering) ||
532 !list_empty(&res->purge)) {
533 mlog(ML_ERROR,
534 "Going to BUG for resource %.*s."
535 " We're on a list! [%c%c%c%c%c%c%c]\n",
536 res->lockname.len, res->lockname.name,
537 !hlist_unhashed(&res->hash_node) ? 'H' : ' ',
538 !list_empty(&res->granted) ? 'G' : ' ',
539 !list_empty(&res->converting) ? 'C' : ' ',
540 !list_empty(&res->blocked) ? 'B' : ' ',
541 !list_empty(&res->dirty) ? 'D' : ' ',
542 !list_empty(&res->recovering) ? 'R' : ' ',
543 !list_empty(&res->purge) ? 'P' : ' ');
544
545 dlm_print_one_lock_resource(res);
546 }
547
6714d8e8
KH		 548 /* By the time we're ready to blow this guy away, we shouldn't
549 * be on any lists. */
81f2094a 550 BUG_ON(!hlist_unhashed(&res->hash_node));
6714d8e8
KH		 551 BUG_ON(!list_empty(&res->granted));
552 BUG_ON(!list_empty(&res->converting));
553 BUG_ON(!list_empty(&res->blocked));
554 BUG_ON(!list_empty(&res->dirty));
555 BUG_ON(!list_empty(&res->recovering));
556 BUG_ON(!list_empty(&res->purge));
557
724bdca9 558 kmem_cache_free(dlm_lockname_cache, (void *)res->lockname.name);
6714d8e8 559
724bdca9 560 kmem_cache_free(dlm_lockres_cache, res);
6714d8e8
KH		 561}
562
6714d8e8
KH		 563void dlm_lockres_put(struct dlm_lock_resource *res)
564{
565 kref_put(&res->refs, dlm_lockres_release);
566}
567
568static void dlm_init_lockres(struct dlm_ctxt *dlm,
569 struct dlm_lock_resource *res,
570 const char *name, unsigned int namelen)
571{
572 char *qname;
573
574 /* If we memset here, we lose our reference to the kmalloc'd
575 * res->lockname.name, so be sure to init every field
576 * correctly! */
577
578 qname = (char *) res->lockname.name;
579 memcpy(qname, name, namelen);
580
581 res->lockname.len = namelen;
a3d33291 582 res->lockname.hash = dlm_lockid_hash(name, namelen);
6714d8e8
KH		 583
584 init_waitqueue_head(&res->wq);
585 spin_lock_init(&res->spinlock);
81f2094a 586 INIT_HLIST_NODE(&res->hash_node);
6714d8e8
KH		 587 INIT_LIST_HEAD(&res->granted);
588 INIT_LIST_HEAD(&res->converting);
589 INIT_LIST_HEAD(&res->blocked);
590 INIT_LIST_HEAD(&res->dirty);
591 INIT_LIST_HEAD(&res->recovering);
592 INIT_LIST_HEAD(&res->purge);
29576f8b 593 INIT_LIST_HEAD(&res->tracking);
6714d8e8
KH		 594 atomic_set(&res->asts_reserved, 0);
595 res->migration_pending = 0;
ba2bf218 596 res->inflight_locks = 0;
6714d8e8
KH		 597
598 kref_init(&res->refs);
599
600 /* just for consistency */
601 spin_lock(&res->spinlock);
602 dlm_set_lockres_owner(dlm, res, DLM_LOCK_RES_OWNER_UNKNOWN);
603 spin_unlock(&res->spinlock);
604
605 res->state = DLM_LOCK_RES_IN_PROGRESS;
606
607 res->last_used = 0;
608
18c6ac38 609 spin_lock(&dlm->spinlock);
29576f8b 610 list_add_tail(&res->tracking, &dlm->tracking_list);
18c6ac38 611 spin_unlock(&dlm->spinlock);
29576f8b 612
6714d8e8 613 memset(res->lvb, 0, DLM_LVB_LEN);
ba2bf218 614 memset(res->refmap, 0, sizeof(res->refmap));
6714d8e8
KH		 615}
616
617struct dlm_lock_resource *dlm_new_lockres(struct dlm_ctxt *dlm,
618 const char *name,
619 unsigned int namelen)
620{
724bdca9 621 struct dlm_lock_resource *res = NULL;
6714d8e8 622
724bdca9
SM		 623 res = (struct dlm_lock_resource *)
624 kmem_cache_zalloc(dlm_lockres_cache, GFP_NOFS);
6714d8e8 625 if (!res)
724bdca9 626 goto error;
6714d8e8 627
724bdca9
SM		 628 res->lockname.name = (char *)
629 kmem_cache_zalloc(dlm_lockname_cache, GFP_NOFS);
630 if (!res->lockname.name)
631 goto error;
6714d8e8
KH		 632
633 dlm_init_lockres(dlm, res, name, namelen);
634 return res;
724bdca9
SM		 635
636error:
637 if (res && res->lockname.name)
638 kmem_cache_free(dlm_lockname_cache, (void *)res->lockname.name);
639
640 if (res)
641 kmem_cache_free(dlm_lockres_cache, res);
642 return NULL;
6714d8e8
KH		 643}
644
ba2bf218
KH		 645void __dlm_lockres_grab_inflight_ref(struct dlm_ctxt *dlm,
646 struct dlm_lock_resource *res,
647 int new_lockres,
648 const char *file,
649 int line)
650{
651 if (!new_lockres)
652 assert_spin_locked(&res->spinlock);
653
654 if (!test_bit(dlm->node_num, res->refmap)) {
655 BUG_ON(res->inflight_locks != 0);
656 dlm_lockres_set_refmap_bit(dlm->node_num, res);
657 }
658 res->inflight_locks++;
659 mlog(0, "%s:%.*s: inflight++: now %u\n",
660 dlm->name, res->lockname.len, res->lockname.name,
661 res->inflight_locks);
662}
663
664void __dlm_lockres_drop_inflight_ref(struct dlm_ctxt *dlm,
665 struct dlm_lock_resource *res,
666 const char *file,
667 int line)
668{
669 assert_spin_locked(&res->spinlock);
670
671 BUG_ON(res->inflight_locks == 0);
672 res->inflight_locks--;
673 mlog(0, "%s:%.*s: inflight--: now %u\n",
674 dlm->name, res->lockname.len, res->lockname.name,
675 res->inflight_locks);
676 if (res->inflight_locks == 0)
677 dlm_lockres_clear_refmap_bit(dlm->node_num, res);
678 wake_up(&res->wq);
679}
680
6714d8e8
KH		 681/*
682 * lookup a lock resource by name.
683 * may already exist in the hashtable.
684 * lockid is null terminated
685 *
686 * if not, allocate enough for the lockres and for
687 * the temporary structure used in doing the mastering.
688 *
689 * also, do a lookup in the dlm->master_list to see
690 * if another node has begun mastering the same lock.
691 * if so, there should be a block entry in there
692 * for this name, and we should *not* attempt to master
693 * the lock here. need to wait around for that node
694 * to assert_master (or die).
695 *
696 */
697struct dlm_lock_resource * dlm_get_lock_resource(struct dlm_ctxt *dlm,
698 const char *lockid,
3384f3df 699 int namelen,
6714d8e8
KH		 700 int flags)
701{
702 struct dlm_lock_resource *tmpres=NULL, *res=NULL;
703 struct dlm_master_list_entry *mle = NULL;
704 struct dlm_master_list_entry *alloc_mle = NULL;
705 int blocked = 0;
706 int ret, nodenum;
707 struct dlm_node_iter iter;
3384f3df 708 unsigned int hash;
6714d8e8 709 int tries = 0;
c03872f5 710 int bit, wait_on_recovery = 0;
ba2bf218 711 int drop_inflight_if_nonlocal = 0;
6714d8e8
KH		 712
713 BUG_ON(!lockid);
714
a3d33291 715 hash = dlm_lockid_hash(lockid, namelen);
6714d8e8
KH		 716
717 mlog(0, "get lockres %s (len %d)\n", lockid, namelen);
718
719lookup:
720 spin_lock(&dlm->spinlock);
ba2bf218 721 tmpres = __dlm_lookup_lockres_full(dlm, lockid, namelen, hash);
6714d8e8 722 if (tmpres) {
ba2bf218
KH		 723 int dropping_ref = 0;
724
725 spin_lock(&tmpres->spinlock);
726 if (tmpres->owner == dlm->node_num) {
727 BUG_ON(tmpres->state & DLM_LOCK_RES_DROPPING_REF);
728 dlm_lockres_grab_inflight_ref(dlm, tmpres);
729 } else if (tmpres->state & DLM_LOCK_RES_DROPPING_REF)
730 dropping_ref = 1;
731 spin_unlock(&tmpres->spinlock);
6714d8e8 732 spin_unlock(&dlm->spinlock);
ba2bf218
KH		 733
734 /* wait until done messaging the master, drop our ref to allow
735 * the lockres to be purged, start over. */
736 if (dropping_ref) {
737 spin_lock(&tmpres->spinlock);
738 __dlm_wait_on_lockres_flags(tmpres, DLM_LOCK_RES_DROPPING_REF);
739 spin_unlock(&tmpres->spinlock);
740 dlm_lockres_put(tmpres);
741 tmpres = NULL;
742 goto lookup;
743 }
744
6714d8e8
KH		 745 mlog(0, "found in hash!\n");
746 if (res)
747 dlm_lockres_put(res);
748 res = tmpres;
749 goto leave;
750 }
751
752 if (!res) {
753 spin_unlock(&dlm->spinlock);
754 mlog(0, "allocating a new resource\n");
755 /* nothing found and we need to allocate one. */
756 alloc_mle = (struct dlm_master_list_entry *)
ad8100e0 757 kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
6714d8e8
KH		 758 if (!alloc_mle)
759 goto leave;
760 res = dlm_new_lockres(dlm, lockid, namelen);
761 if (!res)
762 goto leave;
763 goto lookup;
764 }
765
766 mlog(0, "no lockres found, allocated our own: %p\n", res);
767
768 if (flags & LKM_LOCAL) {
769 /* caller knows it's safe to assume it's not mastered elsewhere
770 * DONE! return right away */
771 spin_lock(&res->spinlock);
772 dlm_change_lockres_owner(dlm, res, dlm->node_num);
773 __dlm_insert_lockres(dlm, res);
ba2bf218 774 dlm_lockres_grab_inflight_ref(dlm, res);
6714d8e8
KH		 775 spin_unlock(&res->spinlock);
776 spin_unlock(&dlm->spinlock);
777 /* lockres still marked IN_PROGRESS */
778 goto wake_waiters;
779 }
780
781 /* check master list to see if another node has started mastering it */
782 spin_lock(&dlm->master_lock);
783
784 /* if we found a block, wait for lock to be mastered by another node */
785 blocked = dlm_find_mle(dlm, &mle, (char *)lockid, namelen);
786 if (blocked) {
ba2bf218 787 int mig;
6714d8e8
KH		 788 if (mle->type == DLM_MLE_MASTER) {
789 mlog(ML_ERROR, "master entry for nonexistent lock!\n");
790 BUG();
ba2bf218
KH		 791 }
792 mig = (mle->type == DLM_MLE_MIGRATION);
793 /* if there is a migration in progress, let the migration
794 * finish before continuing. we can wait for the absence
795 * of the MIGRATION mle: either the migrate finished or
796 * one of the nodes died and the mle was cleaned up.
797 * if there is a BLOCK here, but it already has a master
798 * set, we are too late. the master does not have a ref
799 * for us in the refmap. detach the mle and drop it.
800 * either way, go back to the top and start over. */
801 if (mig || mle->master != O2NM_MAX_NODES) {
802 BUG_ON(mig && mle->master == dlm->node_num);
803 /* we arrived too late. the master does not
804 * have a ref for us. retry. */
805 mlog(0, "%s:%.*s: late on %s\n",
806 dlm->name, namelen, lockid,
807 mig ? "MIGRATION" : "BLOCK");
6714d8e8 808 spin_unlock(&dlm->master_lock);
6714d8e8
KH		 809 spin_unlock(&dlm->spinlock);
810
811 /* master is known, detach */
ba2bf218
KH		 812 if (!mig)
813 dlm_mle_detach_hb_events(dlm, mle);
6714d8e8
KH		 814 dlm_put_mle(mle);
815 mle = NULL;
ba2bf218
KH		 816 /* this is lame, but we cant wait on either
817 * the mle or lockres waitqueue here */
818 if (mig)
819 msleep(100);
820 goto lookup;
6714d8e8
KH		 821 }
822 } else {
823 /* go ahead and try to master lock on this node */
824 mle = alloc_mle;
825 /* make sure this does not get freed below */
826 alloc_mle = NULL;
827 dlm_init_mle(mle, DLM_MLE_MASTER, dlm, res, NULL, 0);
828 set_bit(dlm->node_num, mle->maybe_map);
829 list_add(&mle->list, &dlm->master_list);
c03872f5
KH		 830
831 /* still holding the dlm spinlock, check the recovery map
832 * to see if there are any nodes that still need to be
833 * considered. these will not appear in the mle nodemap
834 * but they might own this lockres. wait on them. */
835 bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
836 if (bit < O2NM_MAX_NODES) {
2759236f 837 mlog(ML_NOTICE, "%s:%.*s: at least one node (%d) to "
c03872f5
KH		 838 "recover before lock mastery can begin\n",
839 dlm->name, namelen, (char *)lockid, bit);
840 wait_on_recovery = 1;
841 }
6714d8e8
KH		 842 }
843
844 /* at this point there is either a DLM_MLE_BLOCK or a
845 * DLM_MLE_MASTER on the master list, so it's safe to add the
846 * lockres to the hashtable. anyone who finds the lock will
847 * still have to wait on the IN_PROGRESS. */
848
849 /* finally add the lockres to its hash bucket */
850 __dlm_insert_lockres(dlm, res);
ba2bf218
KH		 851 /* since this lockres is new it doesnt not require the spinlock */
852 dlm_lockres_grab_inflight_ref_new(dlm, res);
853
854 /* if this node does not become the master make sure to drop
855 * this inflight reference below */
856 drop_inflight_if_nonlocal = 1;
857
6714d8e8
KH		 858 /* get an extra ref on the mle in case this is a BLOCK
859 * if so, the creator of the BLOCK may try to put the last
860 * ref at this time in the assert master handler, so we
861 * need an extra one to keep from a bad ptr deref. */
a2bf0477 862 dlm_get_mle_inuse(mle);
6714d8e8
KH		 863 spin_unlock(&dlm->master_lock);
864 spin_unlock(&dlm->spinlock);
865
e7e69eb3 866redo_request:
c03872f5
KH		 867 while (wait_on_recovery) {
868 /* any cluster changes that occurred after dropping the
869 * dlm spinlock would be detectable be a change on the mle,
870 * so we only need to clear out the recovery map once. */
871 if (dlm_is_recovery_lock(lockid, namelen)) {
872 mlog(ML_NOTICE, "%s: recovery map is not empty, but "
873 "must master $RECOVERY lock now\n", dlm->name);
874 if (!dlm_pre_master_reco_lockres(dlm, res))
875 wait_on_recovery = 0;
876 else {
877 mlog(0, "%s: waiting 500ms for heartbeat state "
878 "change\n", dlm->name);
879 msleep(500);
880 }
881 continue;
882 }
883
884 dlm_kick_recovery_thread(dlm);
aa087b84 885 msleep(1000);
c03872f5
KH		 886 dlm_wait_for_recovery(dlm);
887
888 spin_lock(&dlm->spinlock);
889 bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
890 if (bit < O2NM_MAX_NODES) {
2759236f 891 mlog(ML_NOTICE, "%s:%.*s: at least one node (%d) to "
c03872f5
KH		 892 "recover before lock mastery can begin\n",
893 dlm->name, namelen, (char *)lockid, bit);
894 wait_on_recovery = 1;
895 } else
896 wait_on_recovery = 0;
897 spin_unlock(&dlm->spinlock);
b7084ab5
KH		 898
899 if (wait_on_recovery)
900 dlm_wait_for_node_recovery(dlm, bit, 10000);
c03872f5
KH		 901 }
902
6714d8e8
KH		 903 /* must wait for lock to be mastered elsewhere */
904 if (blocked)
905 goto wait;
906
6714d8e8
KH		 907 ret = -EINVAL;
908 dlm_node_iter_init(mle->vote_map, &iter);
909 while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
ba2bf218 910 ret = dlm_do_master_request(res, mle, nodenum);
6714d8e8
KH		 911 if (ret < 0)
912 mlog_errno(ret);
913 if (mle->master != O2NM_MAX_NODES) {
914 /* found a master ! */
9c6510a5
KH		 915 if (mle->master <= nodenum)
916 break;
917 /* if our master request has not reached the master
918 * yet, keep going until it does. this is how the
919 * master will know that asserts are needed back to
920 * the lower nodes. */
921 mlog(0, "%s:%.*s: requests only up to %u but master "
922 "is %u, keep going\n", dlm->name, namelen,
923 lockid, nodenum, mle->master);
6714d8e8
KH		 924 }
925 }
926
927wait:
928 /* keep going until the response map includes all nodes */
929 ret = dlm_wait_for_lock_mastery(dlm, res, mle, &blocked);
930 if (ret < 0) {
e7e69eb3 931 wait_on_recovery = 1;
6714d8e8
KH		 932 mlog(0, "%s:%.*s: node map changed, redo the "
933 "master request now, blocked=%d\n",
934 dlm->name, res->lockname.len,
935 res->lockname.name, blocked);
936 if (++tries > 20) {
937 mlog(ML_ERROR, "%s:%.*s: spinning on "
938 "dlm_wait_for_lock_mastery, blocked=%d\n",
939 dlm->name, res->lockname.len,
940 res->lockname.name, blocked);
941 dlm_print_one_lock_resource(res);
8a9343fa 942 dlm_print_one_mle(mle);
6714d8e8
KH		 943 tries = 0;
944 }
945 goto redo_request;
946 }
947
948 mlog(0, "lockres mastered by %u\n", res->owner);
949 /* make sure we never continue without this */
950 BUG_ON(res->owner == O2NM_MAX_NODES);
951
952 /* master is known, detach if not already detached */
953 dlm_mle_detach_hb_events(dlm, mle);
954 dlm_put_mle(mle);
955 /* put the extra ref */
a2bf0477 956 dlm_put_mle_inuse(mle);
6714d8e8
KH		 957
958wake_waiters:
959 spin_lock(&res->spinlock);
ba2bf218
KH		 960 if (res->owner != dlm->node_num && drop_inflight_if_nonlocal)
961 dlm_lockres_drop_inflight_ref(dlm, res);
6714d8e8
KH		 962 res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
963 spin_unlock(&res->spinlock);
964 wake_up(&res->wq);
965
966leave:
967 /* need to free the unused mle */
968 if (alloc_mle)
969 kmem_cache_free(dlm_mle_cache, alloc_mle);
970
971 return res;
972}
973
974
975#define DLM_MASTERY_TIMEOUT_MS 5000
976
977static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
978 struct dlm_lock_resource *res,
979 struct dlm_master_list_entry *mle,
980 int *blocked)
981{
982 u8 m;
983 int ret, bit;
984 int map_changed, voting_done;
985 int assert, sleep;
986
987recheck:
988 ret = 0;
989 assert = 0;
990
991 /* check if another node has already become the owner */
992 spin_lock(&res->spinlock);
993 if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
9c6510a5
KH		 994 mlog(0, "%s:%.*s: owner is suddenly %u\n", dlm->name,
995 res->lockname.len, res->lockname.name, res->owner);
6714d8e8 996 spin_unlock(&res->spinlock);
9c6510a5
KH		 997 /* this will cause the master to re-assert across
998 * the whole cluster, freeing up mles */
588e0090 999 if (res->owner != dlm->node_num) {
ba2bf218 1000 ret = dlm_do_master_request(res, mle, res->owner);
588e0090
KH		 1001 if (ret < 0) {
1002 /* give recovery a chance to run */
1003 mlog(ML_ERROR, "link to %u went down?: %d\n", res->owner, ret);
1004 msleep(500);
1005 goto recheck;
1006 }
9c6510a5
KH		 1007 }
1008 ret = 0;
6714d8e8
KH		 1009 goto leave;
1010 }
1011 spin_unlock(&res->spinlock);
1012
1013 spin_lock(&mle->spinlock);
1014 m = mle->master;
1015 map_changed = (memcmp(mle->vote_map, mle->node_map,
1016 sizeof(mle->vote_map)) != 0);
1017 voting_done = (memcmp(mle->vote_map, mle->response_map,
1018 sizeof(mle->vote_map)) == 0);
1019
1020 /* restart if we hit any errors */
1021 if (map_changed) {
1022 int b;
1023 mlog(0, "%s: %.*s: node map changed, restarting\n",
1024 dlm->name, res->lockname.len, res->lockname.name);
1025 ret = dlm_restart_lock_mastery(dlm, res, mle, *blocked);
1026 b = (mle->type == DLM_MLE_BLOCK);
1027 if ((*blocked && !b) || (!*blocked && b)) {
1028 mlog(0, "%s:%.*s: status change: old=%d new=%d\n",
1029 dlm->name, res->lockname.len, res->lockname.name,
1030 *blocked, b);
1031 *blocked = b;
1032 }
1033 spin_unlock(&mle->spinlock);
1034 if (ret < 0) {
1035 mlog_errno(ret);
1036 goto leave;
1037 }
1038 mlog(0, "%s:%.*s: restart lock mastery succeeded, "
1039 "rechecking now\n", dlm->name, res->lockname.len,
1040 res->lockname.name);
1041 goto recheck;
aa852354
KH		 1042 } else {
1043 if (!voting_done) {
1044 mlog(0, "map not changed and voting not done "
1045 "for %s:%.*s\n", dlm->name, res->lockname.len,
1046 res->lockname.name);
1047 }
6714d8e8
KH		 1048 }
1049
1050 if (m != O2NM_MAX_NODES) {
1051 /* another node has done an assert!
1052 * all done! */
1053 sleep = 0;
1054 } else {
1055 sleep = 1;
1056 /* have all nodes responded? */
1057 if (voting_done && !*blocked) {
1058 bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
1059 if (dlm->node_num <= bit) {
1060 /* my node number is lowest.
1061 * now tell other nodes that I am
1062 * mastering this. */
1063 mle->master = dlm->node_num;
ba2bf218
KH		 1064 /* ref was grabbed in get_lock_resource
1065 * will be dropped in dlmlock_master */
6714d8e8
KH		 1066 assert = 1;
1067 sleep = 0;
1068 }
1069 /* if voting is done, but we have not received
1070 * an assert master yet, we must sleep */
1071 }
1072 }
1073
1074 spin_unlock(&mle->spinlock);
1075
1076 /* sleep if we haven't finished voting yet */
1077 if (sleep) {
1078 unsigned long timeo = msecs_to_jiffies(DLM_MASTERY_TIMEOUT_MS);
1079
1080 /*
1081 if (atomic_read(&mle->mle_refs.refcount) < 2)
1082 mlog(ML_ERROR, "mle (%p) refs=%d, name=%.*s\n", mle,
1083 atomic_read(&mle->mle_refs.refcount),
1084 res->lockname.len, res->lockname.name);
1085 */
1086 atomic_set(&mle->woken, 0);
1087 (void)wait_event_timeout(mle->wq,
1088 (atomic_read(&mle->woken) == 1),
1089 timeo);
1090 if (res->owner == O2NM_MAX_NODES) {
ba2bf218
KH		 1091 mlog(0, "%s:%.*s: waiting again\n", dlm->name,
1092 res->lockname.len, res->lockname.name);
6714d8e8
KH		 1093 goto recheck;
1094 }
1095 mlog(0, "done waiting, master is %u\n", res->owner);
1096 ret = 0;
1097 goto leave;
1098 }
1099
1100 ret = 0; /* done */
1101 if (assert) {
1102 m = dlm->node_num;
1103 mlog(0, "about to master %.*s here, this=%u\n",
1104 res->lockname.len, res->lockname.name, m);
ba2bf218 1105 ret = dlm_do_assert_master(dlm, res, mle->vote_map, 0);
6714d8e8
KH		 1106 if (ret) {
1107 /* This is a failure in the network path,
1108 * not in the response to the assert_master
1109 * (any nonzero response is a BUG on this node).
1110 * Most likely a socket just got disconnected
1111 * due to node death. */
1112 mlog_errno(ret);
1113 }
1114 /* no longer need to restart lock mastery.
1115 * all living nodes have been contacted. */
1116 ret = 0;
1117 }
1118
1119 /* set the lockres owner */
1120 spin_lock(&res->spinlock);
ba2bf218
KH		 1121 /* mastery reference obtained either during
1122 * assert_master_handler or in get_lock_resource */
6714d8e8
KH		 1123 dlm_change_lockres_owner(dlm, res, m);
1124 spin_unlock(&res->spinlock);
1125
1126leave:
1127 return ret;
1128}
1129
1130struct dlm_bitmap_diff_iter
1131{
1132 int curnode;
1133 unsigned long *orig_bm;
1134 unsigned long *cur_bm;
1135 unsigned long diff_bm[BITS_TO_LONGS(O2NM_MAX_NODES)];
1136};
1137
1138enum dlm_node_state_change
1139{
1140 NODE_DOWN = -1,
1141 NODE_NO_CHANGE = 0,
1142 NODE_UP
1143};
1144
1145static void dlm_bitmap_diff_iter_init(struct dlm_bitmap_diff_iter *iter,
1146 unsigned long *orig_bm,
1147 unsigned long *cur_bm)
1148{
1149 unsigned long p1, p2;
1150 int i;
1151
1152 iter->curnode = -1;
1153 iter->orig_bm = orig_bm;
1154 iter->cur_bm = cur_bm;
1155
1156 for (i = 0; i < BITS_TO_LONGS(O2NM_MAX_NODES); i++) {
1157 p1 = *(iter->orig_bm + i);
1158 p2 = *(iter->cur_bm + i);
1159 iter->diff_bm[i] = (p1 & ~p2) | (p2 & ~p1);
1160 }
1161}
1162
1163static int dlm_bitmap_diff_iter_next(struct dlm_bitmap_diff_iter *iter,
1164 enum dlm_node_state_change *state)
1165{
1166 int bit;
1167
1168 if (iter->curnode >= O2NM_MAX_NODES)
1169 return -ENOENT;
1170
1171 bit = find_next_bit(iter->diff_bm, O2NM_MAX_NODES,
1172 iter->curnode+1);
1173 if (bit >= O2NM_MAX_NODES) {
1174 iter->curnode = O2NM_MAX_NODES;
1175 return -ENOENT;
1176 }
1177
1178 /* if it was there in the original then this node died */
1179 if (test_bit(bit, iter->orig_bm))
1180 *state = NODE_DOWN;
1181 else
1182 *state = NODE_UP;
1183
1184 iter->curnode = bit;
1185 return bit;
1186}
1187
1188
1189static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
1190 struct dlm_lock_resource *res,
1191 struct dlm_master_list_entry *mle,
1192 int blocked)
1193{
1194 struct dlm_bitmap_diff_iter bdi;
1195 enum dlm_node_state_change sc;
1196 int node;
1197 int ret = 0;
1198
1199 mlog(0, "something happened such that the "
1200 "master process may need to be restarted!\n");
1201
1202 assert_spin_locked(&mle->spinlock);
1203
1204 dlm_bitmap_diff_iter_init(&bdi, mle->vote_map, mle->node_map);
1205 node = dlm_bitmap_diff_iter_next(&bdi, &sc);
1206 while (node >= 0) {
1207 if (sc == NODE_UP) {
e2faea4c
KH		 1208 /* a node came up. clear any old vote from
1209 * the response map and set it in the vote map
1210 * then restart the mastery. */
1211 mlog(ML_NOTICE, "node %d up while restarting\n", node);
6714d8e8
KH		 1212
1213 /* redo the master request, but only for the new node */
1214 mlog(0, "sending request to new node\n");
1215 clear_bit(node, mle->response_map);
1216 set_bit(node, mle->vote_map);
1217 } else {
1218 mlog(ML_ERROR, "node down! %d\n", node);
6714d8e8
KH		 1219 if (blocked) {
1220 int lowest = find_next_bit(mle->maybe_map,
1221 O2NM_MAX_NODES, 0);
1222
1223 /* act like it was never there */
1224 clear_bit(node, mle->maybe_map);
1225
e7e69eb3
KH		 1226 if (node == lowest) {
1227 mlog(0, "expected master %u died"
1228 " while this node was blocked "
1229 "waiting on it!\n", node);
1230 lowest = find_next_bit(mle->maybe_map,
1231 O2NM_MAX_NODES,
1232 lowest+1);
1233 if (lowest < O2NM_MAX_NODES) {
1234 mlog(0, "%s:%.*s:still "
1235 "blocked. waiting on %u "
1236 "now\n", dlm->name,
1237 res->lockname.len,
1238 res->lockname.name,
1239 lowest);
1240 } else {
1241 /* mle is an MLE_BLOCK, but
1242 * there is now nothing left to
1243 * block on. we need to return
1244 * all the way back out and try
1245 * again with an MLE_MASTER.
1246 * dlm_do_local_recovery_cleanup
1247 * has already run, so the mle
1248 * refcount is ok */
1249 mlog(0, "%s:%.*s: no "
1250 "longer blocking. try to "
1251 "master this here\n",
1252 dlm->name,
1253 res->lockname.len,
1254 res->lockname.name);
1255 mle->type = DLM_MLE_MASTER;
1256 mle->u.res = res;
1257 }
6714d8e8 1258 }
6714d8e8
KH		 1259 }
1260
e7e69eb3
KH		 1261 /* now blank out everything, as if we had never
1262 * contacted anyone */
1263 memset(mle->maybe_map, 0, sizeof(mle->maybe_map));
1264 memset(mle->response_map, 0, sizeof(mle->response_map));
1265 /* reset the vote_map to the current node_map */
1266 memcpy(mle->vote_map, mle->node_map,
1267 sizeof(mle->node_map));
1268 /* put myself into the maybe map */
1269 if (mle->type != DLM_MLE_BLOCK)
1270 set_bit(dlm->node_num, mle->maybe_map);
6714d8e8
KH		 1271 }
1272 ret = -EAGAIN;
6714d8e8
KH		 1273 node = dlm_bitmap_diff_iter_next(&bdi, &sc);
1274 }
1275 return ret;
1276}
1277
1278
1279/*
1280 * DLM_MASTER_REQUEST_MSG
1281 *
1282 * returns: 0 on success,
1283 * -errno on a network error
1284 *
1285 * on error, the caller should assume the target node is "dead"
1286 *
1287 */
1288
ba2bf218
KH		 1289static int dlm_do_master_request(struct dlm_lock_resource *res,
1290 struct dlm_master_list_entry *mle, int to)
6714d8e8
KH		 1291{
1292 struct dlm_ctxt *dlm = mle->dlm;
1293 struct dlm_master_request request;
1294 int ret, response=0, resend;
1295
1296 memset(&request, 0, sizeof(request));
1297 request.node_idx = dlm->node_num;
1298
1299 BUG_ON(mle->type == DLM_MLE_MIGRATION);
1300
1301 if (mle->type != DLM_MLE_MASTER) {
1302 request.namelen = mle->u.name.len;
1303 memcpy(request.name, mle->u.name.name, request.namelen);
1304 } else {
1305 request.namelen = mle->u.res->lockname.len;
1306 memcpy(request.name, mle->u.res->lockname.name,
1307 request.namelen);
1308 }
1309
1310again:
1311 ret = o2net_send_message(DLM_MASTER_REQUEST_MSG, dlm->key, &request,
1312 sizeof(request), to, &response);
1313 if (ret < 0) {
1314 if (ret == -ESRCH) {
1315 /* should never happen */
1316 mlog(ML_ERROR, "TCP stack not ready!\n");
1317 BUG();
1318 } else if (ret == -EINVAL) {
1319 mlog(ML_ERROR, "bad args passed to o2net!\n");
1320 BUG();
1321 } else if (ret == -ENOMEM) {
1322 mlog(ML_ERROR, "out of memory while trying to send "
1323 "network message! retrying\n");
1324 /* this is totally crude */
1325 msleep(50);
1326 goto again;
1327 } else if (!dlm_is_host_down(ret)) {
1328 /* not a network error. bad. */
1329 mlog_errno(ret);
1330 mlog(ML_ERROR, "unhandled error!");
1331 BUG();
1332 }
1333 /* all other errors should be network errors,
1334 * and likely indicate node death */
1335 mlog(ML_ERROR, "link to %d went down!\n", to);
1336 goto out;
1337 }
1338
1339 ret = 0;
1340 resend = 0;
1341 spin_lock(&mle->spinlock);
1342 switch (response) {
1343 case DLM_MASTER_RESP_YES:
1344 set_bit(to, mle->response_map);
1345 mlog(0, "node %u is the master, response=YES\n", to);
ba2bf218
KH		 1346 mlog(0, "%s:%.*s: master node %u now knows I have a "
1347 "reference\n", dlm->name, res->lockname.len,
1348 res->lockname.name, to);
6714d8e8
KH		 1349 mle->master = to;
1350 break;
1351 case DLM_MASTER_RESP_NO:
1352 mlog(0, "node %u not master, response=NO\n", to);
1353 set_bit(to, mle->response_map);
1354 break;
1355 case DLM_MASTER_RESP_MAYBE:
1356 mlog(0, "node %u not master, response=MAYBE\n", to);
1357 set_bit(to, mle->response_map);
1358 set_bit(to, mle->maybe_map);
1359 break;
1360 case DLM_MASTER_RESP_ERROR:
1361 mlog(0, "node %u hit an error, resending\n", to);
1362 resend = 1;
1363 response = 0;
1364 break;
1365 default:
1366 mlog(ML_ERROR, "bad response! %u\n", response);
1367 BUG();
1368 }
1369 spin_unlock(&mle->spinlock);
1370 if (resend) {
1371 /* this is also totally crude */
1372 msleep(50);
1373 goto again;
1374 }
1375
1376out:
1377 return ret;
1378}
1379
1380/*
1381 * locks that can be taken here:
1382 * dlm->spinlock
1383 * res->spinlock
1384 * mle->spinlock
1385 * dlm->master_list
1386 *
1387 * if possible, TRIM THIS DOWN!!!
1388 */
d74c9803
KH		 1389int dlm_master_request_handler(struct o2net_msg *msg, u32 len, void *data,
1390 void **ret_data)
6714d8e8
KH		 1391{
1392 u8 response = DLM_MASTER_RESP_MAYBE;
1393 struct dlm_ctxt *dlm = data;
9c6510a5 1394 struct dlm_lock_resource *res = NULL;
6714d8e8
KH		 1395 struct dlm_master_request *request = (struct dlm_master_request *) msg->buf;
1396 struct dlm_master_list_entry *mle = NULL, *tmpmle = NULL;
1397 char *name;
a3d33291 1398 unsigned int namelen, hash;
6714d8e8
KH		 1399 int found, ret;
1400 int set_maybe;
9c6510a5 1401 int dispatch_assert = 0;
6714d8e8
KH		 1402
1403 if (!dlm_grab(dlm))
1404 return DLM_MASTER_RESP_NO;
1405
1406 if (!dlm_domain_fully_joined(dlm)) {
1407 response = DLM_MASTER_RESP_NO;
1408 goto send_response;
1409 }
1410
1411 name = request->name;
1412 namelen = request->namelen;
a3d33291 1413 hash = dlm_lockid_hash(name, namelen);
6714d8e8
KH		 1414
1415 if (namelen > DLM_LOCKID_NAME_MAX) {
1416 response = DLM_IVBUFLEN;
1417 goto send_response;
1418 }
1419
1420way_up_top:
1421 spin_lock(&dlm->spinlock);
a3d33291 1422 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
6714d8e8
KH		 1423 if (res) {
1424 spin_unlock(&dlm->spinlock);
1425
1426 /* take care of the easy cases up front */
1427 spin_lock(&res->spinlock);
1cd04dbe
KH		 1428 if (res->state & (DLM_LOCK_RES_RECOVERING|
1429 DLM_LOCK_RES_MIGRATING)) {
6714d8e8
KH		 1430 spin_unlock(&res->spinlock);
1431 mlog(0, "returning DLM_MASTER_RESP_ERROR since res is "
1cd04dbe 1432 "being recovered/migrated\n");
6714d8e8
KH		 1433 response = DLM_MASTER_RESP_ERROR;
1434 if (mle)
1435 kmem_cache_free(dlm_mle_cache, mle);
1436 goto send_response;
1437 }
1438
1439 if (res->owner == dlm->node_num) {
ba2bf218
KH		 1440 mlog(0, "%s:%.*s: setting bit %u in refmap\n",
1441 dlm->name, namelen, name, request->node_idx);
1442 dlm_lockres_set_refmap_bit(request->node_idx, res);
6714d8e8 1443 spin_unlock(&res->spinlock);
6714d8e8
KH		 1444 response = DLM_MASTER_RESP_YES;
1445 if (mle)
1446 kmem_cache_free(dlm_mle_cache, mle);
1447
1448 /* this node is the owner.
1449 * there is some extra work that needs to
1450 * happen now. the requesting node has
1451 * caused all nodes up to this one to
1452 * create mles. this node now needs to
1453 * go back and clean those up. */
9c6510a5 1454 dispatch_assert = 1;
6714d8e8
KH		 1455 goto send_response;
1456 } else if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1457 spin_unlock(&res->spinlock);
1458 // mlog(0, "node %u is the master\n", res->owner);
1459 response = DLM_MASTER_RESP_NO;
1460 if (mle)
1461 kmem_cache_free(dlm_mle_cache, mle);
1462 goto send_response;
1463 }
1464
1465 /* ok, there is no owner. either this node is
1466 * being blocked, or it is actively trying to
1467 * master this lock. */
1468 if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
1469 mlog(ML_ERROR, "lock with no owner should be "
1470 "in-progress!\n");
1471 BUG();
1472 }
1473
1474 // mlog(0, "lockres is in progress...\n");
1475 spin_lock(&dlm->master_lock);
1476 found = dlm_find_mle(dlm, &tmpmle, name, namelen);
1477 if (!found) {
1478 mlog(ML_ERROR, "no mle found for this lock!\n");
1479 BUG();
1480 }
1481 set_maybe = 1;
1482 spin_lock(&tmpmle->spinlock);
1483 if (tmpmle->type == DLM_MLE_BLOCK) {
1484 // mlog(0, "this node is waiting for "
1485 // "lockres to be mastered\n");
1486 response = DLM_MASTER_RESP_NO;
1487 } else if (tmpmle->type == DLM_MLE_MIGRATION) {
1488 mlog(0, "node %u is master, but trying to migrate to "
1489 "node %u.\n", tmpmle->master, tmpmle->new_master);
1490 if (tmpmle->master == dlm->node_num) {
6714d8e8
KH		 1491 mlog(ML_ERROR, "no owner on lockres, but this "
1492 "node is trying to migrate it to %u?!\n",
1493 tmpmle->new_master);
1494 BUG();
1495 } else {
1496 /* the real master can respond on its own */
1497 response = DLM_MASTER_RESP_NO;
1498 }
1499 } else if (tmpmle->master != DLM_LOCK_RES_OWNER_UNKNOWN) {
1500 set_maybe = 0;
9c6510a5 1501 if (tmpmle->master == dlm->node_num) {
6714d8e8 1502 response = DLM_MASTER_RESP_YES;
9c6510a5
KH		 1503 /* this node will be the owner.
1504 * go back and clean the mles on any
1505 * other nodes */
1506 dispatch_assert = 1;
ba2bf218
KH		 1507 dlm_lockres_set_refmap_bit(request->node_idx, res);
1508 mlog(0, "%s:%.*s: setting bit %u in refmap\n",
1509 dlm->name, namelen, name,
1510 request->node_idx);
9c6510a5 1511 } else
6714d8e8
KH		 1512 response = DLM_MASTER_RESP_NO;
1513 } else {
1514 // mlog(0, "this node is attempting to "
1515 // "master lockres\n");
1516 response = DLM_MASTER_RESP_MAYBE;
1517 }
1518 if (set_maybe)
1519 set_bit(request->node_idx, tmpmle->maybe_map);
1520 spin_unlock(&tmpmle->spinlock);
1521
1522 spin_unlock(&dlm->master_lock);
1523 spin_unlock(&res->spinlock);
1524
1525 /* keep the mle attached to heartbeat events */
1526 dlm_put_mle(tmpmle);
1527 if (mle)
1528 kmem_cache_free(dlm_mle_cache, mle);
1529 goto send_response;
1530 }
1531
1532 /*
1533 * lockres doesn't exist on this node
1534 * if there is an MLE_BLOCK, return NO
1535 * if there is an MLE_MASTER, return MAYBE
1536 * otherwise, add an MLE_BLOCK, return NO
1537 */
1538 spin_lock(&dlm->master_lock);
1539 found = dlm_find_mle(dlm, &tmpmle, name, namelen);
1540 if (!found) {
1541 /* this lockid has never been seen on this node yet */
1542 // mlog(0, "no mle found\n");
1543 if (!mle) {
1544 spin_unlock(&dlm->master_lock);
1545 spin_unlock(&dlm->spinlock);
1546
1547 mle = (struct dlm_master_list_entry *)
ad8100e0 1548 kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
6714d8e8 1549 if (!mle) {
6714d8e8 1550 response = DLM_MASTER_RESP_ERROR;
9c6510a5 1551 mlog_errno(-ENOMEM);
6714d8e8
KH		 1552 goto send_response;
1553 }
6714d8e8
KH		 1554 goto way_up_top;
1555 }
1556
1557 // mlog(0, "this is second time thru, already allocated, "
1558 // "add the block.\n");
41b8c8a1 1559 dlm_init_mle(mle, DLM_MLE_BLOCK, dlm, NULL, name, namelen);
6714d8e8
KH		 1560 set_bit(request->node_idx, mle->maybe_map);
1561 list_add(&mle->list, &dlm->master_list);
1562 response = DLM_MASTER_RESP_NO;
1563 } else {
1564 // mlog(0, "mle was found\n");
1565 set_maybe = 1;
1566 spin_lock(&tmpmle->spinlock);
9c6510a5
KH		 1567 if (tmpmle->master == dlm->node_num) {
1568 mlog(ML_ERROR, "no lockres, but an mle with this node as master!\n");
1569 BUG();
1570 }
6714d8e8
KH		 1571 if (tmpmle->type == DLM_MLE_BLOCK)
1572 response = DLM_MASTER_RESP_NO;
1573 else if (tmpmle->type == DLM_MLE_MIGRATION) {
1574 mlog(0, "migration mle was found (%u->%u)\n",
1575 tmpmle->master, tmpmle->new_master);
6714d8e8
KH		 1576 /* real master can respond on its own */
1577 response = DLM_MASTER_RESP_NO;
9c6510a5
KH		 1578 } else
1579 response = DLM_MASTER_RESP_MAYBE;
6714d8e8
KH		 1580 if (set_maybe)
1581 set_bit(request->node_idx, tmpmle->maybe_map);
1582 spin_unlock(&tmpmle->spinlock);
1583 }
1584 spin_unlock(&dlm->master_lock);
1585 spin_unlock(&dlm->spinlock);
1586
1587 if (found) {
1588 /* keep the mle attached to heartbeat events */
1589 dlm_put_mle(tmpmle);
1590 }
1591send_response:
b31cfc02
SM		 1592 /*
1593 * __dlm_lookup_lockres() grabbed a reference to this lockres.
1594 * The reference is released by dlm_assert_master_worker() under
1595 * the call to dlm_dispatch_assert_master(). If
1596 * dlm_assert_master_worker() isn't called, we drop it here.
1597 */
9c6510a5
KH		 1598 if (dispatch_assert) {
1599 if (response != DLM_MASTER_RESP_YES)
1600 mlog(ML_ERROR, "invalid response %d\n", response);
1601 if (!res) {
1602 mlog(ML_ERROR, "bad lockres while trying to assert!\n");
1603 BUG();
1604 }
1605 mlog(0, "%u is the owner of %.*s, cleaning everyone else\n",
1606 dlm->node_num, res->lockname.len, res->lockname.name);
1607 ret = dlm_dispatch_assert_master(dlm, res, 0, request->node_idx,
1608 DLM_ASSERT_MASTER_MLE_CLEANUP);
1609 if (ret < 0) {
1610 mlog(ML_ERROR, "failed to dispatch assert master work\n");
1611 response = DLM_MASTER_RESP_ERROR;
b31cfc02 1612 dlm_lockres_put(res);
9c6510a5 1613 }
b31cfc02
SM		 1614 } else {
1615 if (res)
1616 dlm_lockres_put(res);
9c6510a5
KH		 1617 }
1618
6714d8e8
KH		 1619 dlm_put(dlm);
1620 return response;
1621}
1622
1623/*
1624 * DLM_ASSERT_MASTER_MSG
1625 */
1626
1627
1628/*
1629 * NOTE: this can be used for debugging
1630 * can periodically run all locks owned by this node
1631 * and re-assert across the cluster...
1632 */
05488bbe
AB		 1633static int dlm_do_assert_master(struct dlm_ctxt *dlm,
1634 struct dlm_lock_resource *res,
1635 void *nodemap, u32 flags)
6714d8e8
KH		 1636{
1637 struct dlm_assert_master assert;
1638 int to, tmpret;
1639 struct dlm_node_iter iter;
1640 int ret = 0;
9c6510a5 1641 int reassert;
ba2bf218
KH		 1642 const char *lockname = res->lockname.name;
1643 unsigned int namelen = res->lockname.len;
6714d8e8
KH		 1644
1645 BUG_ON(namelen > O2NM_MAX_NAME_LEN);
f3f85464
SM		 1646
1647 spin_lock(&res->spinlock);
1648 res->state |= DLM_LOCK_RES_SETREF_INPROG;
1649 spin_unlock(&res->spinlock);
1650
9c6510a5
KH		 1651again:
1652 reassert = 0;
6714d8e8
KH		 1653
1654 /* note that if this nodemap is empty, it returns 0 */
1655 dlm_node_iter_init(nodemap, &iter);
1656 while ((to = dlm_node_iter_next(&iter)) >= 0) {
1657 int r = 0;
a9ee4c8a
KH		 1658 struct dlm_master_list_entry *mle = NULL;
1659
6714d8e8
KH		 1660 mlog(0, "sending assert master to %d (%.*s)\n", to,
1661 namelen, lockname);
1662 memset(&assert, 0, sizeof(assert));
1663 assert.node_idx = dlm->node_num;
1664 assert.namelen = namelen;
1665 memcpy(assert.name, lockname, namelen);
1666 assert.flags = cpu_to_be32(flags);
1667
1668 tmpret = o2net_send_message(DLM_ASSERT_MASTER_MSG, dlm->key,
1669 &assert, sizeof(assert), to, &r);
1670 if (tmpret < 0) {
3b3b84a8 1671 mlog(0, "assert_master returned %d!\n", tmpret);
6714d8e8 1672 if (!dlm_is_host_down(tmpret)) {
3b3b84a8 1673 mlog(ML_ERROR, "unhandled error=%d!\n", tmpret);
6714d8e8
KH		 1674 BUG();
1675 }
1676 /* a node died. finish out the rest of the nodes. */
3b3b84a8 1677 mlog(0, "link to %d went down!\n", to);
6714d8e8
KH		 1678 /* any nonzero status return will do */
1679 ret = tmpret;
ba2bf218 1680 r = 0;
6714d8e8
KH		 1681 } else if (r < 0) {
1682 /* ok, something horribly messed. kill thyself. */
1683 mlog(ML_ERROR,"during assert master of %.*s to %u, "
1684 "got %d.\n", namelen, lockname, to, r);
a9ee4c8a
KH		 1685 spin_lock(&dlm->spinlock);
1686 spin_lock(&dlm->master_lock);
1687 if (dlm_find_mle(dlm, &mle, (char *)lockname,
1688 namelen)) {
1689 dlm_print_one_mle(mle);
1690 __dlm_put_mle(mle);
1691 }
1692 spin_unlock(&dlm->master_lock);
1693 spin_unlock(&dlm->spinlock);
6714d8e8 1694 BUG();
ba2bf218
KH		 1695 }
1696
1697 if (r & DLM_ASSERT_RESPONSE_REASSERT &&
1698 !(r & DLM_ASSERT_RESPONSE_MASTERY_REF)) {
1699 mlog(ML_ERROR, "%.*s: very strange, "
1700 "master MLE but no lockres on %u\n",
1701 namelen, lockname, to);
1702 }
1703
1704 if (r & DLM_ASSERT_RESPONSE_REASSERT) {
9c6510a5
KH		 1705 mlog(0, "%.*s: node %u create mles on other "
1706 "nodes and requests a re-assert\n",
1707 namelen, lockname, to);
1708 reassert = 1;
6714d8e8 1709 }
ba2bf218
KH		 1710 if (r & DLM_ASSERT_RESPONSE_MASTERY_REF) {
1711 mlog(0, "%.*s: node %u has a reference to this "
1712 "lockres, set the bit in the refmap\n",
1713 namelen, lockname, to);
1714 spin_lock(&res->spinlock);
1715 dlm_lockres_set_refmap_bit(to, res);
1716 spin_unlock(&res->spinlock);
1717 }
6714d8e8
KH		 1718 }
1719
9c6510a5
KH		 1720 if (reassert)
1721 goto again;
1722
f3f85464
SM		 1723 spin_lock(&res->spinlock);
1724 res->state &= ~DLM_LOCK_RES_SETREF_INPROG;
1725 spin_unlock(&res->spinlock);
1726 wake_up(&res->wq);
1727
6714d8e8
KH		 1728 return ret;
1729}
1730
1731/*
1732 * locks that can be taken here:
1733 * dlm->spinlock
1734 * res->spinlock
1735 * mle->spinlock
1736 * dlm->master_list
1737 *
1738 * if possible, TRIM THIS DOWN!!!
1739 */
d74c9803
KH		 1740int dlm_assert_master_handler(struct o2net_msg *msg, u32 len, void *data,
1741 void **ret_data)
6714d8e8
KH		 1742{
1743 struct dlm_ctxt *dlm = data;
1744 struct dlm_master_list_entry *mle = NULL;
1745 struct dlm_assert_master *assert = (struct dlm_assert_master *)msg->buf;
1746 struct dlm_lock_resource *res = NULL;
1747 char *name;
a3d33291 1748 unsigned int namelen, hash;
6714d8e8 1749 u32 flags;
ba2bf218 1750 int master_request = 0, have_lockres_ref = 0;
9c6510a5 1751 int ret = 0;
6714d8e8
KH		 1752
1753 if (!dlm_grab(dlm))
1754 return 0;
1755
1756 name = assert->name;
1757 namelen = assert->namelen;
a3d33291 1758 hash = dlm_lockid_hash(name, namelen);
6714d8e8
KH		 1759 flags = be32_to_cpu(assert->flags);
1760
1761 if (namelen > DLM_LOCKID_NAME_MAX) {
1762 mlog(ML_ERROR, "Invalid name length!");
1763 goto done;
1764 }
1765
1766 spin_lock(&dlm->spinlock);
1767
1768 if (flags)
1769 mlog(0, "assert_master with flags: %u\n", flags);
1770
1771 /* find the MLE */
1772 spin_lock(&dlm->master_lock);
1773 if (!dlm_find_mle(dlm, &mle, name, namelen)) {
1774 /* not an error, could be master just re-asserting */
1775 mlog(0, "just got an assert_master from %u, but no "
1776 "MLE for it! (%.*s)\n", assert->node_idx,
1777 namelen, name);
1778 } else {
1779 int bit = find_next_bit (mle->maybe_map, O2NM_MAX_NODES, 0);
1780 if (bit >= O2NM_MAX_NODES) {
1781 /* not necessarily an error, though less likely.
1782 * could be master just re-asserting. */
aa852354 1783 mlog(0, "no bits set in the maybe_map, but %u "
6714d8e8
KH		 1784 "is asserting! (%.*s)\n", assert->node_idx,
1785 namelen, name);
1786 } else if (bit != assert->node_idx) {
1787 if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
1788 mlog(0, "master %u was found, %u should "
1789 "back off\n", assert->node_idx, bit);
1790 } else {
1791 /* with the fix for bug 569, a higher node
1792 * number winning the mastery will respond
1793 * YES to mastery requests, but this node
1794 * had no way of knowing. let it pass. */
aa852354 1795 mlog(0, "%u is the lowest node, "
6714d8e8
KH		 1796 "%u is asserting. (%.*s) %u must "
1797 "have begun after %u won.\n", bit,
1798 assert->node_idx, namelen, name, bit,
1799 assert->node_idx);
1800 }
1801 }
2d1a868c
KH		 1802 if (mle->type == DLM_MLE_MIGRATION) {
1803 if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
1804 mlog(0, "%s:%.*s: got cleanup assert"
1805 " from %u for migration\n",
1806 dlm->name, namelen, name,
1807 assert->node_idx);
1808 } else if (!(flags & DLM_ASSERT_MASTER_FINISH_MIGRATION)) {
1809 mlog(0, "%s:%.*s: got unrelated assert"
1810 " from %u for migration, ignoring\n",
1811 dlm->name, namelen, name,
1812 assert->node_idx);
1813 __dlm_put_mle(mle);
1814 spin_unlock(&dlm->master_lock);
1815 spin_unlock(&dlm->spinlock);
1816 goto done;
1817 }
1818 }
6714d8e8
KH		 1819 }
1820 spin_unlock(&dlm->master_lock);
1821
1822 /* ok everything checks out with the MLE
1823 * now check to see if there is a lockres */
a3d33291 1824 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
6714d8e8
KH		 1825 if (res) {
1826 spin_lock(&res->spinlock);
1827 if (res->state & DLM_LOCK_RES_RECOVERING) {
1828 mlog(ML_ERROR, "%u asserting but %.*s is "
1829 "RECOVERING!\n", assert->node_idx, namelen, name);
1830 goto kill;
1831 }
1832 if (!mle) {
dc2ed195
KH		 1833 if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN &&
1834 res->owner != assert->node_idx) {
6714d8e8
KH		 1835 mlog(ML_ERROR, "assert_master from "
1836 "%u, but current owner is "
1837 "%u! (%.*s)\n",
1838 assert->node_idx, res->owner,
1839 namelen, name);
1840 goto kill;
1841 }
1842 } else if (mle->type != DLM_MLE_MIGRATION) {
1843 if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1844 /* owner is just re-asserting */
1845 if (res->owner == assert->node_idx) {
1846 mlog(0, "owner %u re-asserting on "
1847 "lock %.*s\n", assert->node_idx,
1848 namelen, name);
1849 goto ok;
1850 }
1851 mlog(ML_ERROR, "got assert_master from "
1852 "node %u, but %u is the owner! "
1853 "(%.*s)\n", assert->node_idx,
1854 res->owner, namelen, name);
1855 goto kill;
1856 }
1857 if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
1858 mlog(ML_ERROR, "got assert from %u, but lock "
1859 "with no owner should be "
1860 "in-progress! (%.*s)\n",
1861 assert->node_idx,
1862 namelen, name);
1863 goto kill;
1864 }
1865 } else /* mle->type == DLM_MLE_MIGRATION */ {
1866 /* should only be getting an assert from new master */
1867 if (assert->node_idx != mle->new_master) {
1868 mlog(ML_ERROR, "got assert from %u, but "
1869 "new master is %u, and old master "
1870 "was %u (%.*s)\n",
1871 assert->node_idx, mle->new_master,
1872 mle->master, namelen, name);
1873 goto kill;
1874 }
1875
1876 }
1877ok:
1878 spin_unlock(&res->spinlock);
1879 }
1880 spin_unlock(&dlm->spinlock);
1881
1882 // mlog(0, "woo! got an assert_master from node %u!\n",
1883 // assert->node_idx);
1884 if (mle) {
9c6510a5
KH		 1885 int extra_ref = 0;
1886 int nn = -1;
a2bf0477 1887 int rr, err = 0;
6714d8e8
KH		 1888
1889 spin_lock(&mle->spinlock);
9c6510a5
KH		 1890 if (mle->type == DLM_MLE_BLOCK || mle->type == DLM_MLE_MIGRATION)
1891 extra_ref = 1;
1892 else {
1893 /* MASTER mle: if any bits set in the response map
1894 * then the calling node needs to re-assert to clear
1895 * up nodes that this node contacted */
1896 while ((nn = find_next_bit (mle->response_map, O2NM_MAX_NODES,
1897 nn+1)) < O2NM_MAX_NODES) {
1898 if (nn != dlm->node_num && nn != assert->node_idx)
1899 master_request = 1;
1900 }
1901 }
6714d8e8
KH		 1902 mle->master = assert->node_idx;
1903 atomic_set(&mle->woken, 1);
1904 wake_up(&mle->wq);
1905 spin_unlock(&mle->spinlock);
1906
a2bf0477 1907 if (res) {
a6fa3640 1908 int wake = 0;
6714d8e8 1909 spin_lock(&res->spinlock);
a2bf0477
KH		 1910 if (mle->type == DLM_MLE_MIGRATION) {
1911 mlog(0, "finishing off migration of lockres %.*s, "
1912 "from %u to %u\n",
1913 res->lockname.len, res->lockname.name,
1914 dlm->node_num, mle->new_master);
1915 res->state &= ~DLM_LOCK_RES_MIGRATING;
a6fa3640 1916 wake = 1;
a2bf0477
KH		 1917 dlm_change_lockres_owner(dlm, res, mle->new_master);
1918 BUG_ON(res->state & DLM_LOCK_RES_DIRTY);
1919 } else {
1920 dlm_change_lockres_owner(dlm, res, mle->master);
1921 }
6714d8e8 1922 spin_unlock(&res->spinlock);
ba2bf218 1923 have_lockres_ref = 1;
a6fa3640
KH		 1924 if (wake)
1925 wake_up(&res->wq);
6714d8e8 1926 }
a2bf0477
KH		 1927
1928 /* master is known, detach if not already detached.
1929 * ensures that only one assert_master call will happen
1930 * on this mle. */
1931 spin_lock(&dlm->spinlock);
1932 spin_lock(&dlm->master_lock);
1933
1934 rr = atomic_read(&mle->mle_refs.refcount);
1935 if (mle->inuse > 0) {
1936 if (extra_ref && rr < 3)
1937 err = 1;
1938 else if (!extra_ref && rr < 2)
1939 err = 1;
1940 } else {
1941 if (extra_ref && rr < 2)
1942 err = 1;
1943 else if (!extra_ref && rr < 1)
1944 err = 1;
1945 }
1946 if (err) {
1947 mlog(ML_ERROR, "%s:%.*s: got assert master from %u "
1948 "that will mess up this node, refs=%d, extra=%d, "
1949 "inuse=%d\n", dlm->name, namelen, name,
1950 assert->node_idx, rr, extra_ref, mle->inuse);
1951 dlm_print_one_mle(mle);
1952 }
1953 list_del_init(&mle->list);
1954 __dlm_mle_detach_hb_events(dlm, mle);
1955 __dlm_put_mle(mle);
6714d8e8
KH		 1956 if (extra_ref) {
1957 /* the assert master message now balances the extra
1958 * ref given by the master / migration request message.
1959 * if this is the last put, it will be removed
1960 * from the list. */
a2bf0477
KH		 1961 __dlm_put_mle(mle);
1962 }
1963 spin_unlock(&dlm->master_lock);
1964 spin_unlock(&dlm->spinlock);
1965 } else if (res) {
1966 if (res->owner != assert->node_idx) {
1967 mlog(0, "assert_master from %u, but current "
1968 "owner is %u (%.*s), no mle\n", assert->node_idx,
1969 res->owner, namelen, name);
6714d8e8
KH		 1970 }
1971 }
1972
1973done:
9c6510a5 1974 ret = 0;
3b8118cf
KH		 1975 if (res) {
1976 spin_lock(&res->spinlock);
1977 res->state |= DLM_LOCK_RES_SETREF_INPROG;
1978 spin_unlock(&res->spinlock);
1979 *ret_data = (void *)res;
1980 }
6714d8e8 1981 dlm_put(dlm);
9c6510a5
KH		 1982 if (master_request) {
1983 mlog(0, "need to tell master to reassert\n");
ba2bf218
KH		 1984 /* positive. negative would shoot down the node. */
1985 ret |= DLM_ASSERT_RESPONSE_REASSERT;
1986 if (!have_lockres_ref) {
1987 mlog(ML_ERROR, "strange, got assert from %u, MASTER "
1988 "mle present here for %s:%.*s, but no lockres!\n",
1989 assert->node_idx, dlm->name, namelen, name);
1990 }
1991 }
1992 if (have_lockres_ref) {
1993 /* let the master know we have a reference to the lockres */
1994 ret |= DLM_ASSERT_RESPONSE_MASTERY_REF;
1995 mlog(0, "%s:%.*s: got assert from %u, need a ref\n",
1996 dlm->name, namelen, name, assert->node_idx);
9c6510a5
KH		 1997 }
1998 return ret;
6714d8e8
KH		 1999
2000kill:
2001 /* kill the caller! */
a9ee4c8a
KH		 2002 mlog(ML_ERROR, "Bad message received from another node. Dumping state "
2003 "and killing the other node now! This node is OK and can continue.\n");
2004 __dlm_print_one_lock_resource(res);
6714d8e8
KH		 2005 spin_unlock(&res->spinlock);
2006 spin_unlock(&dlm->spinlock);
3b8118cf 2007 *ret_data = (void *)res;
6714d8e8
KH		 2008 dlm_put(dlm);
2009 return -EINVAL;
2010}
2011
3b8118cf
KH		 2012void dlm_assert_master_post_handler(int status, void *data, void *ret_data)
2013{
2014 struct dlm_lock_resource *res = (struct dlm_lock_resource *)ret_data;
2015
2016 if (ret_data) {
2017 spin_lock(&res->spinlock);
2018 res->state &= ~DLM_LOCK_RES_SETREF_INPROG;
2019 spin_unlock(&res->spinlock);
2020 wake_up(&res->wq);
2021 dlm_lockres_put(res);
2022 }
2023 return;
2024}
2025
6714d8e8
KH		 2026int dlm_dispatch_assert_master(struct dlm_ctxt *dlm,
2027 struct dlm_lock_resource *res,
2028 int ignore_higher, u8 request_from, u32 flags)
2029{
2030 struct dlm_work_item *item;
cd861280 2031 item = kzalloc(sizeof(*item), GFP_NOFS);
6714d8e8
KH		 2032 if (!item)
2033 return -ENOMEM;
2034
2035
2036 /* queue up work for dlm_assert_master_worker */
2037 dlm_grab(dlm); /* get an extra ref for the work item */
2038 dlm_init_work_item(dlm, item, dlm_assert_master_worker, NULL);
2039 item->u.am.lockres = res; /* already have a ref */
2040 /* can optionally ignore node numbers higher than this node */
2041 item->u.am.ignore_higher = ignore_higher;
2042 item->u.am.request_from = request_from;
2043 item->u.am.flags = flags;
2044
9c6510a5
KH		 2045 if (ignore_higher)
2046 mlog(0, "IGNORE HIGHER: %.*s\n", res->lockname.len,
2047 res->lockname.name);
2048
6714d8e8
KH		 2049 spin_lock(&dlm->work_lock);
2050 list_add_tail(&item->list, &dlm->work_list);
2051 spin_unlock(&dlm->work_lock);
2052
3156d267 2053 queue_work(dlm->dlm_worker, &dlm->dispatched_work);
6714d8e8
KH		 2054 return 0;
2055}
2056
2057static void dlm_assert_master_worker(struct dlm_work_item *item, void *data)
2058{
2059 struct dlm_ctxt *dlm = data;
2060 int ret = 0;
2061 struct dlm_lock_resource *res;
2062 unsigned long nodemap[BITS_TO_LONGS(O2NM_MAX_NODES)];
2063 int ignore_higher;
2064 int bit;
2065 u8 request_from;
2066 u32 flags;
2067
2068 dlm = item->dlm;
2069 res = item->u.am.lockres;
2070 ignore_higher = item->u.am.ignore_higher;
2071 request_from = item->u.am.request_from;
2072 flags = item->u.am.flags;
2073
2074 spin_lock(&dlm->spinlock);
2075 memcpy(nodemap, dlm->domain_map, sizeof(nodemap));
2076 spin_unlock(&dlm->spinlock);
2077
2078 clear_bit(dlm->node_num, nodemap);
2079 if (ignore_higher) {
2080 /* if is this just to clear up mles for nodes below
2081 * this node, do not send the message to the original
2082 * caller or any node number higher than this */
2083 clear_bit(request_from, nodemap);
2084 bit = dlm->node_num;
2085 while (1) {
2086 bit = find_next_bit(nodemap, O2NM_MAX_NODES,
2087 bit+1);
2088 if (bit >= O2NM_MAX_NODES)
2089 break;
2090 clear_bit(bit, nodemap);
2091 }
2092 }
2093
36407488
KH		 2094 /*
2095 * If we're migrating this lock to someone else, we are no
2096 * longer allowed to assert out own mastery. OTOH, we need to
2097 * prevent migration from starting while we're still asserting
2098 * our dominance. The reserved ast delays migration.
2099 */
2100 spin_lock(&res->spinlock);
2101 if (res->state & DLM_LOCK_RES_MIGRATING) {
2102 mlog(0, "Someone asked us to assert mastery, but we're "
2103 "in the middle of migration. Skipping assert, "
2104 "the new master will handle that.\n");
2105 spin_unlock(&res->spinlock);
2106 goto put;
2107 } else
2108 __dlm_lockres_reserve_ast(res);
2109 spin_unlock(&res->spinlock);
2110
6714d8e8
KH		 2111 /* this call now finishes out the nodemap
2112 * even if one or more nodes die */
2113 mlog(0, "worker about to master %.*s here, this=%u\n",
2114 res->lockname.len, res->lockname.name, dlm->node_num);
ba2bf218 2115 ret = dlm_do_assert_master(dlm, res, nodemap, flags);
6714d8e8
KH		 2116 if (ret < 0) {
2117 /* no need to restart, we are done */
3b3b84a8
KH		 2118 if (!dlm_is_host_down(ret))
2119 mlog_errno(ret);
6714d8e8
KH		 2120 }
2121
36407488
KH		 2122 /* Ok, we've asserted ourselves. Let's let migration start. */
2123 dlm_lockres_release_ast(dlm, res);
2124
2125put:
6714d8e8
KH		 2126 dlm_lockres_put(res);
2127
2128 mlog(0, "finished with dlm_assert_master_worker\n");
2129}
2130
c03872f5
KH		 2131/* SPECIAL CASE for the $RECOVERY lock used by the recovery thread.
2132 * We cannot wait for node recovery to complete to begin mastering this
2133 * lockres because this lockres is used to kick off recovery! ;-)
2134 * So, do a pre-check on all living nodes to see if any of those nodes
2135 * think that $RECOVERY is currently mastered by a dead node. If so,
2136 * we wait a short time to allow that node to get notified by its own
2137 * heartbeat stack, then check again. All $RECOVERY lock resources
2138 * mastered by dead nodes are purged when the hearbeat callback is
2139 * fired, so we can know for sure that it is safe to continue once
2140 * the node returns a live node or no node. */
2141static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
2142 struct dlm_lock_resource *res)
2143{
2144 struct dlm_node_iter iter;
2145 int nodenum;
2146 int ret = 0;
2147 u8 master = DLM_LOCK_RES_OWNER_UNKNOWN;
2148
2149 spin_lock(&dlm->spinlock);
2150 dlm_node_iter_init(dlm->domain_map, &iter);
2151 spin_unlock(&dlm->spinlock);
2152
2153 while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
2154 /* do not send to self */
2155 if (nodenum == dlm->node_num)
2156 continue;
2157 ret = dlm_do_master_requery(dlm, res, nodenum, &master);
2158 if (ret < 0) {
2159 mlog_errno(ret);
2160 if (!dlm_is_host_down(ret))
2161 BUG();
2162 /* host is down, so answer for that node would be
2163 * DLM_LOCK_RES_OWNER_UNKNOWN. continue. */
f42a100b 2164 ret = 0;
c03872f5
KH		 2165 }
2166
2167 if (master != DLM_LOCK_RES_OWNER_UNKNOWN) {
2168 /* check to see if this master is in the recovery map */
2169 spin_lock(&dlm->spinlock);
2170 if (test_bit(master, dlm->recovery_map)) {
2171 mlog(ML_NOTICE, "%s: node %u has not seen "
2172 "node %u go down yet, and thinks the "
2173 "dead node is mastering the recovery "
2174 "lock. must wait.\n", dlm->name,
2175 nodenum, master);
2176 ret = -EAGAIN;
2177 }
2178 spin_unlock(&dlm->spinlock);
2179 mlog(0, "%s: reco lock master is %u\n", dlm->name,
2180 master);
2181 break;
2182 }
2183 }
2184 return ret;
2185}
2186
ba2bf218
KH		 2187/*
2188 * DLM_DEREF_LOCKRES_MSG
2189 */
2190
2191int dlm_drop_lockres_ref(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
2192{
2193 struct dlm_deref_lockres deref;
2194 int ret = 0, r;
2195 const char *lockname;
2196 unsigned int namelen;
2197
2198 lockname = res->lockname.name;
2199 namelen = res->lockname.len;
2200 BUG_ON(namelen > O2NM_MAX_NAME_LEN);
2201
2202 mlog(0, "%s:%.*s: sending deref to %d\n",
2203 dlm->name, namelen, lockname, res->owner);
2204 memset(&deref, 0, sizeof(deref));
2205 deref.node_idx = dlm->node_num;
2206 deref.namelen = namelen;
2207 memcpy(deref.name, lockname, namelen);
2208
2209 ret = o2net_send_message(DLM_DEREF_LOCKRES_MSG, dlm->key,
2210 &deref, sizeof(deref), res->owner, &r);
2211 if (ret < 0)
2212 mlog_errno(ret);
2213 else if (r < 0) {
2214 /* BAD. other node says I did not have a ref. */
2215 mlog(ML_ERROR,"while dropping ref on %s:%.*s "
2216 "(master=%u) got %d.\n", dlm->name, namelen,
2217 lockname, res->owner, r);
2218 dlm_print_one_lock_resource(res);
2219 BUG();
2220 }
2221 return ret;
2222}
2223
d74c9803
KH		 2224int dlm_deref_lockres_handler(struct o2net_msg *msg, u32 len, void *data,
2225 void **ret_data)
ba2bf218
KH		 2226{
2227 struct dlm_ctxt *dlm = data;
2228 struct dlm_deref_lockres *deref = (struct dlm_deref_lockres *)msg->buf;
2229 struct dlm_lock_resource *res = NULL;
2230 char *name;
2231 unsigned int namelen;
2232 int ret = -EINVAL;
2233 u8 node;
2234 unsigned int hash;
f3f85464
SM		 2235 struct dlm_work_item *item;
2236 int cleared = 0;
2237 int dispatch = 0;
ba2bf218
KH		 2238
2239 if (!dlm_grab(dlm))
2240 return 0;
2241
2242 name = deref->name;
2243 namelen = deref->namelen;
2244 node = deref->node_idx;
2245
2246 if (namelen > DLM_LOCKID_NAME_MAX) {
2247 mlog(ML_ERROR, "Invalid name length!");
2248 goto done;
2249 }
2250 if (deref->node_idx >= O2NM_MAX_NODES) {
2251 mlog(ML_ERROR, "Invalid node number: %u\n", node);
2252 goto done;
2253 }
2254
2255 hash = dlm_lockid_hash(name, namelen);
2256
2257 spin_lock(&dlm->spinlock);
2258 res = __dlm_lookup_lockres_full(dlm, name, namelen, hash);
2259 if (!res) {
2260 spin_unlock(&dlm->spinlock);
2261 mlog(ML_ERROR, "%s:%.*s: bad lockres name\n",
2262 dlm->name, namelen, name);
2263 goto done;
2264 }
2265 spin_unlock(&dlm->spinlock);
2266
2267 spin_lock(&res->spinlock);
f3f85464
SM		 2268 if (res->state & DLM_LOCK_RES_SETREF_INPROG)
2269 dispatch = 1;
2270 else {
2271 BUG_ON(res->state & DLM_LOCK_RES_DROPPING_REF);
2272 if (test_bit(node, res->refmap)) {
2273 dlm_lockres_clear_refmap_bit(node, res);
2274 cleared = 1;
2275 }
ba2bf218
KH		 2276 }
2277 spin_unlock(&res->spinlock);
2278
f3f85464
SM		 2279 if (!dispatch) {
2280 if (cleared)
2281 dlm_lockres_calc_usage(dlm, res);
2282 else {
2283 mlog(ML_ERROR, "%s:%.*s: node %u trying to drop ref "
2284 "but it is already dropped!\n", dlm->name,
2285 res->lockname.len, res->lockname.name, node);
2af37ce8 2286 dlm_print_one_lock_resource(res);
f3f85464
SM		 2287 }
2288 ret = 0;
2289 goto done;
2290 }
2291
2292 item = kzalloc(sizeof(*item), GFP_NOFS);
2293 if (!item) {
2294 ret = -ENOMEM;
2295 mlog_errno(ret);
2296 goto done;
2297 }
2298
2299 dlm_init_work_item(dlm, item, dlm_deref_lockres_worker, NULL);
2300 item->u.dl.deref_res = res;
2301 item->u.dl.deref_node = node;
2302
2303 spin_lock(&dlm->work_lock);
2304 list_add_tail(&item->list, &dlm->work_list);
2305 spin_unlock(&dlm->work_lock);
2306
2307 queue_work(dlm->dlm_worker, &dlm->dispatched_work);
2308 return 0;
2309
ba2bf218
KH		 2310done:
2311 if (res)
2312 dlm_lockres_put(res);
2313 dlm_put(dlm);
f3f85464 2314
ba2bf218
KH		 2315 return ret;
2316}
2317
f3f85464
SM		 2318static void dlm_deref_lockres_worker(struct dlm_work_item *item, void *data)
2319{
2320 struct dlm_ctxt *dlm;
2321 struct dlm_lock_resource *res;
2322 u8 node;
2323 u8 cleared = 0;
2324
2325 dlm = item->dlm;
2326 res = item->u.dl.deref_res;
2327 node = item->u.dl.deref_node;
2328
2329 spin_lock(&res->spinlock);
2330 BUG_ON(res->state & DLM_LOCK_RES_DROPPING_REF);
2331 if (test_bit(node, res->refmap)) {
2332 __dlm_wait_on_lockres_flags(res, DLM_LOCK_RES_SETREF_INPROG);
2333 dlm_lockres_clear_refmap_bit(node, res);
2334 cleared = 1;
2335 }
2336 spin_unlock(&res->spinlock);
2337
2338 if (cleared) {
2339 mlog(0, "%s:%.*s node %u ref dropped in dispatch\n",
2340 dlm->name, res->lockname.len, res->lockname.name, node);
2341 dlm_lockres_calc_usage(dlm, res);
2342 } else {
2343 mlog(ML_ERROR, "%s:%.*s: node %u trying to drop ref "
2344 "but it is already dropped!\n", dlm->name,
2345 res->lockname.len, res->lockname.name, node);
2af37ce8 2346 dlm_print_one_lock_resource(res);
f3f85464
SM		 2347 }
2348
2349 dlm_lockres_put(res);
2350}
2351
2f5bf1f2
SM		 2352/* Checks whether the lockres can be migrated. Returns 0 if yes, < 0
2353 * if not. If 0, numlocks is set to the number of locks in the lockres.
2354 */
2355static int dlm_is_lockres_migrateable(struct dlm_ctxt *dlm,
2356 struct dlm_lock_resource *res,
2357 int *numlocks)
2358{
2359 int ret;
2360 int i;
2361 int count = 0;
800deef3 2362 struct list_head *queue;
2f5bf1f2
SM		 2363 struct dlm_lock *lock;
2364
2365 assert_spin_locked(&res->spinlock);
2366
2367 ret = -EINVAL;
2368 if (res->owner == DLM_LOCK_RES_OWNER_UNKNOWN) {
2369 mlog(0, "cannot migrate lockres with unknown owner!\n");
2370 goto leave;
2371 }
2372
2373 if (res->owner != dlm->node_num) {
2374 mlog(0, "cannot migrate lockres this node doesn't own!\n");
2375 goto leave;
2376 }
2377
2378 ret = 0;
2379 queue = &res->granted;
2380 for (i = 0; i < 3; i++) {
800deef3 2381 list_for_each_entry(lock, queue, list) {
2f5bf1f2
SM		 2382 ++count;
2383 if (lock->ml.node == dlm->node_num) {
2384 mlog(0, "found a lock owned by this node still "
2385 "on the %s queue! will not migrate this "
2386 "lockres\n", (i == 0 ? "granted" :
2387 (i == 1 ? "converting" :
2388 "blocked")));
2389 ret = -ENOTEMPTY;
2390 goto leave;
2391 }
2392 }
2393 queue++;
2394 }
2395
2396 *numlocks = count;
2397 mlog(0, "migrateable lockres having %d locks\n", *numlocks);
2398
2399leave:
2400 return ret;
2401}
6714d8e8
KH		 2402
2403/*
2404 * DLM_MIGRATE_LOCKRES
2405 */
2406
2407
faf0ec9f
AB		 2408static int dlm_migrate_lockres(struct dlm_ctxt *dlm,
2409 struct dlm_lock_resource *res,
2410 u8 target)
6714d8e8
KH		 2411{
2412 struct dlm_master_list_entry *mle = NULL;
2413 struct dlm_master_list_entry *oldmle = NULL;
2414 struct dlm_migratable_lockres *mres = NULL;
2f5bf1f2 2415 int ret = 0;
6714d8e8
KH		 2416 const char *name;
2417 unsigned int namelen;
2418 int mle_added = 0;
2f5bf1f2
SM		 2419 int numlocks;
2420 int wake = 0;
6714d8e8
KH		 2421
2422 if (!dlm_grab(dlm))
2423 return -EINVAL;
2424
2425 name = res->lockname.name;
2426 namelen = res->lockname.len;
2427
2428 mlog(0, "migrating %.*s to %u\n", namelen, name, target);
2429
2430 /*
2431 * ensure this lockres is a proper candidate for migration
2432 */
2433 spin_lock(&res->spinlock);
2f5bf1f2
SM		 2434 ret = dlm_is_lockres_migrateable(dlm, res, &numlocks);
2435 if (ret < 0) {
6714d8e8
KH		 2436 spin_unlock(&res->spinlock);
2437 goto leave;
2438 }
6714d8e8
KH		 2439 spin_unlock(&res->spinlock);
2440
2441 /* no work to do */
2f5bf1f2 2442 if (numlocks == 0) {
6714d8e8 2443 mlog(0, "no locks were found on this lockres! done!\n");
6714d8e8
KH		 2444 goto leave;
2445 }
2446
2447 /*
2448 * preallocate up front
2449 * if this fails, abort
2450 */
2451
2452 ret = -ENOMEM;
ad8100e0 2453 mres = (struct dlm_migratable_lockres *) __get_free_page(GFP_NOFS);
6714d8e8
KH		 2454 if (!mres) {
2455 mlog_errno(ret);
2456 goto leave;
2457 }
2458
2459 mle = (struct dlm_master_list_entry *) kmem_cache_alloc(dlm_mle_cache,
ad8100e0 2460 GFP_NOFS);
6714d8e8
KH		 2461 if (!mle) {
2462 mlog_errno(ret);
2463 goto leave;
2464 }
2465 ret = 0;
2466
2467 /*
2468 * find a node to migrate the lockres to
2469 */
2470
2471 mlog(0, "picking a migration node\n");
2472 spin_lock(&dlm->spinlock);
2473 /* pick a new node */
2474 if (!test_bit(target, dlm->domain_map) ||
2475 target >= O2NM_MAX_NODES) {
2476 target = dlm_pick_migration_target(dlm, res);
2477 }
2478 mlog(0, "node %u chosen for migration\n", target);
2479
2480 if (target >= O2NM_MAX_NODES ||
2481 !test_bit(target, dlm->domain_map)) {
2482 /* target chosen is not alive */
2483 ret = -EINVAL;
2484 }
2485
2486 if (ret) {
2487 spin_unlock(&dlm->spinlock);
2488 goto fail;
2489 }
2490
2491 mlog(0, "continuing with target = %u\n", target);
2492
2493 /*
2494 * clear any existing master requests and
2495 * add the migration mle to the list
2496 */
2497 spin_lock(&dlm->master_lock);
2498 ret = dlm_add_migration_mle(dlm, res, mle, &oldmle, name,
2499 namelen, target, dlm->node_num);
2500 spin_unlock(&dlm->master_lock);
2501 spin_unlock(&dlm->spinlock);
2502
2503 if (ret == -EEXIST) {
2504 mlog(0, "another process is already migrating it\n");
2505 goto fail;
2506 }
2507 mle_added = 1;
2508
2509 /*
2510 * set the MIGRATING flag and flush asts
2511 * if we fail after this we need to re-dirty the lockres
2512 */
2513 if (dlm_mark_lockres_migrating(dlm, res, target) < 0) {
2514 mlog(ML_ERROR, "tried to migrate %.*s to %u, but "
2515 "the target went down.\n", res->lockname.len,
2516 res->lockname.name, target);
2517 spin_lock(&res->spinlock);
2518 res->state &= ~DLM_LOCK_RES_MIGRATING;
a6fa3640 2519 wake = 1;
6714d8e8
KH		 2520 spin_unlock(&res->spinlock);
2521 ret = -EINVAL;
2522 }
2523
2524fail:
2525 if (oldmle) {
2526 /* master is known, detach if not already detached */
2527 dlm_mle_detach_hb_events(dlm, oldmle);
2528 dlm_put_mle(oldmle);
2529 }
2530
2531 if (ret < 0) {
2532 if (mle_added) {
2533 dlm_mle_detach_hb_events(dlm, mle);
2534 dlm_put_mle(mle);
2535 } else if (mle) {
2536 kmem_cache_free(dlm_mle_cache, mle);
2537 }
2538 goto leave;
2539 }
2540
2541 /*
2542 * at this point, we have a migration target, an mle
2543 * in the master list, and the MIGRATING flag set on
2544 * the lockres
2545 */
2546
1cd04dbe
KH		 2547 /* now that remote nodes are spinning on the MIGRATING flag,
2548 * ensure that all assert_master work is flushed. */
2549 flush_workqueue(dlm->dlm_worker);
6714d8e8
KH		 2550
2551 /* get an extra reference on the mle.
2552 * otherwise the assert_master from the new
2553 * master will destroy this.
2554 * also, make sure that all callers of dlm_get_mle
2555 * take both dlm->spinlock and dlm->master_lock */
2556 spin_lock(&dlm->spinlock);
2557 spin_lock(&dlm->master_lock);
a2bf0477 2558 dlm_get_mle_inuse(mle);
6714d8e8
KH		 2559 spin_unlock(&dlm->master_lock);
2560 spin_unlock(&dlm->spinlock);
2561
2562 /* notify new node and send all lock state */
2563 /* call send_one_lockres with migration flag.
2564 * this serves as notice to the target node that a
2565 * migration is starting. */
2566 ret = dlm_send_one_lockres(dlm, res, mres, target,
2567 DLM_MRES_MIGRATION);
2568
2569 if (ret < 0) {
2570 mlog(0, "migration to node %u failed with %d\n",
2571 target, ret);
2572 /* migration failed, detach and clean up mle */
2573 dlm_mle_detach_hb_events(dlm, mle);
2574 dlm_put_mle(mle);
a2bf0477
KH		 2575 dlm_put_mle_inuse(mle);
2576 spin_lock(&res->spinlock);
2577 res->state &= ~DLM_LOCK_RES_MIGRATING;
a6fa3640 2578 wake = 1;
a2bf0477 2579 spin_unlock(&res->spinlock);
6714d8e8
KH		 2580 goto leave;
2581 }
2582
2583 /* at this point, the target sends a message to all nodes,
2584 * (using dlm_do_migrate_request). this node is skipped since
2585 * we had to put an mle in the list to begin the process. this
2586 * node now waits for target to do an assert master. this node
2587 * will be the last one notified, ensuring that the migration
2588 * is complete everywhere. if the target dies while this is
2589 * going on, some nodes could potentially see the target as the
2590 * master, so it is important that my recovery finds the migration
2591 * mle and sets the master to UNKNONWN. */
2592
2593
2594 /* wait for new node to assert master */
2595 while (1) {
2596 ret = wait_event_interruptible_timeout(mle->wq,
2597 (atomic_read(&mle->woken) == 1),
2598 msecs_to_jiffies(5000));
2599
2600 if (ret >= 0) {
2601 if (atomic_read(&mle->woken) == 1 ||
2602 res->owner == target)
2603 break;
2604
1cd04dbe
KH		 2605 mlog(0, "%s:%.*s: timed out during migration\n",
2606 dlm->name, res->lockname.len, res->lockname.name);
e2faea4c
KH		 2607 /* avoid hang during shutdown when migrating lockres
2608 * to a node which also goes down */
2609 if (dlm_is_node_dead(dlm, target)) {
aa852354
KH		 2610 mlog(0, "%s:%.*s: expected migration "
2611 "target %u is no longer up, restarting\n",
e2faea4c
KH		 2612 dlm->name, res->lockname.len,
2613 res->lockname.name, target);
1cd04dbe
KH		 2614 ret = -EINVAL;
2615 /* migration failed, detach and clean up mle */
2616 dlm_mle_detach_hb_events(dlm, mle);
2617 dlm_put_mle(mle);
2618 dlm_put_mle_inuse(mle);
2619 spin_lock(&res->spinlock);
2620 res->state &= ~DLM_LOCK_RES_MIGRATING;
a6fa3640 2621 wake = 1;
1cd04dbe
KH		 2622 spin_unlock(&res->spinlock);
2623 goto leave;
e2faea4c 2624 }
1cd04dbe
KH		 2625 } else
2626 mlog(0, "%s:%.*s: caught signal during migration\n",
2627 dlm->name, res->lockname.len, res->lockname.name);
6714d8e8
KH		 2628 }
2629
2630 /* all done, set the owner, clear the flag */
2631 spin_lock(&res->spinlock);
2632 dlm_set_lockres_owner(dlm, res, target);
2633 res->state &= ~DLM_LOCK_RES_MIGRATING;
2634 dlm_remove_nonlocal_locks(dlm, res);
2635 spin_unlock(&res->spinlock);
2636 wake_up(&res->wq);
2637
2638 /* master is known, detach if not already detached */
2639 dlm_mle_detach_hb_events(dlm, mle);
a2bf0477 2640 dlm_put_mle_inuse(mle);
6714d8e8
KH		 2641 ret = 0;
2642
2643 dlm_lockres_calc_usage(dlm, res);
2644
2645leave:
2646 /* re-dirty the lockres if we failed */
2647 if (ret < 0)
2648 dlm_kick_thread(dlm, res);
2649
a6fa3640
KH		 2650 /* wake up waiters if the MIGRATING flag got set
2651 * but migration failed */
2652 if (wake)
2653 wake_up(&res->wq);
2654
6714d8e8
KH		 2655 /* TODO: cleanup */
2656 if (mres)
2657 free_page((unsigned long)mres);
2658
2659 dlm_put(dlm);
2660
2661 mlog(0, "returning %d\n", ret);
2662 return ret;
2663}
6714d8e8 2664
ba2bf218
KH		 2665#define DLM_MIGRATION_RETRY_MS 100
2666
2667/* Should be called only after beginning the domain leave process.
2668 * There should not be any remaining locks on nonlocal lock resources,
2669 * and there should be no local locks left on locally mastered resources.
2670 *
2671 * Called with the dlm spinlock held, may drop it to do migration, but
2672 * will re-acquire before exit.
2673 *
2674 * Returns: 1 if dlm->spinlock was dropped/retaken, 0 if never dropped */
2675int dlm_empty_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
2676{
2677 int ret;
2678 int lock_dropped = 0;
2f5bf1f2 2679 int numlocks;
ba2bf218 2680
b36c3f84 2681 spin_lock(&res->spinlock);
ba2bf218
KH		 2682 if (res->owner != dlm->node_num) {
2683 if (!__dlm_lockres_unused(res)) {
2684 mlog(ML_ERROR, "%s:%.*s: this node is not master, "
2685 "trying to free this but locks remain\n",
2686 dlm->name, res->lockname.len, res->lockname.name);
2687 }
b36c3f84 2688 spin_unlock(&res->spinlock);
ba2bf218
KH		 2689 goto leave;
2690 }
2f5bf1f2
SM		 2691
2692 /* No need to migrate a lockres having no locks */
2693 ret = dlm_is_lockres_migrateable(dlm, res, &numlocks);
2694 if (ret >= 0 && numlocks == 0) {
2695 spin_unlock(&res->spinlock);
2696 goto leave;
2697 }
b36c3f84 2698 spin_unlock(&res->spinlock);
ba2bf218
KH		 2699
2700 /* Wheee! Migrate lockres here! Will sleep so drop spinlock. */
2701 spin_unlock(&dlm->spinlock);
2702 lock_dropped = 1;
2703 while (1) {
2704 ret = dlm_migrate_lockres(dlm, res, O2NM_MAX_NODES);
2705 if (ret >= 0)
2706 break;
2707 if (ret == -ENOTEMPTY) {
2708 mlog(ML_ERROR, "lockres %.*s still has local locks!\n",
2709 res->lockname.len, res->lockname.name);
2710 BUG();
2711 }
2712
2713 mlog(0, "lockres %.*s: migrate failed, "
2714 "retrying\n", res->lockname.len,
2715 res->lockname.name);
2716 msleep(DLM_MIGRATION_RETRY_MS);
2717 }
2718 spin_lock(&dlm->spinlock);
2719leave:
2720 return lock_dropped;
2721}
2722
6714d8e8
KH		 2723int dlm_lock_basts_flushed(struct dlm_ctxt *dlm, struct dlm_lock *lock)
2724{
2725 int ret;
2726 spin_lock(&dlm->ast_lock);
2727 spin_lock(&lock->spinlock);
2728 ret = (list_empty(&lock->bast_list) && !lock->bast_pending);
2729 spin_unlock(&lock->spinlock);
2730 spin_unlock(&dlm->ast_lock);
2731 return ret;
2732}
2733
2734static int dlm_migration_can_proceed(struct dlm_ctxt *dlm,
2735 struct dlm_lock_resource *res,
2736 u8 mig_target)
2737{
2738 int can_proceed;
2739 spin_lock(&res->spinlock);
2740 can_proceed = !!(res->state & DLM_LOCK_RES_MIGRATING);
2741 spin_unlock(&res->spinlock);
2742
2743 /* target has died, so make the caller break out of the
2744 * wait_event, but caller must recheck the domain_map */
2745 spin_lock(&dlm->spinlock);
2746 if (!test_bit(mig_target, dlm->domain_map))
2747 can_proceed = 1;
2748 spin_unlock(&dlm->spinlock);
2749 return can_proceed;
2750}
2751
faf0ec9f
AB		 2752static int dlm_lockres_is_dirty(struct dlm_ctxt *dlm,
2753 struct dlm_lock_resource *res)
6714d8e8
KH		 2754{
2755 int ret;
2756 spin_lock(&res->spinlock);
2757 ret = !!(res->state & DLM_LOCK_RES_DIRTY);
2758 spin_unlock(&res->spinlock);
2759 return ret;
2760}
2761
2762
2763static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
2764 struct dlm_lock_resource *res,
2765 u8 target)
2766{
2767 int ret = 0;
2768
2769 mlog(0, "dlm_mark_lockres_migrating: %.*s, from %u to %u\n",
2770 res->lockname.len, res->lockname.name, dlm->node_num,
2771 target);
2772 /* need to set MIGRATING flag on lockres. this is done by
2773 * ensuring that all asts have been flushed for this lockres. */
2774 spin_lock(&res->spinlock);
2775 BUG_ON(res->migration_pending);
2776 res->migration_pending = 1;
2777 /* strategy is to reserve an extra ast then release
2778 * it below, letting the release do all of the work */
2779 __dlm_lockres_reserve_ast(res);
2780 spin_unlock(&res->spinlock);
2781
ddc09c8d 2782 /* now flush all the pending asts */
6714d8e8 2783 dlm_kick_thread(dlm, res);
ddc09c8d
KH		 2784 /* before waiting on DIRTY, block processes which may
2785 * try to dirty the lockres before MIGRATING is set */
2786 spin_lock(&res->spinlock);
2787 BUG_ON(res->state & DLM_LOCK_RES_BLOCK_DIRTY);
2788 res->state |= DLM_LOCK_RES_BLOCK_DIRTY;
2789 spin_unlock(&res->spinlock);
2790 /* now wait on any pending asts and the DIRTY state */
6714d8e8
KH		 2791 wait_event(dlm->ast_wq, !dlm_lockres_is_dirty(dlm, res));
2792 dlm_lockres_release_ast(dlm, res);
2793
2794 mlog(0, "about to wait on migration_wq, dirty=%s\n",
2795 res->state & DLM_LOCK_RES_DIRTY ? "yes" : "no");
2796 /* if the extra ref we just put was the final one, this
2797 * will pass thru immediately. otherwise, we need to wait
2798 * for the last ast to finish. */
2799again:
2800 ret = wait_event_interruptible_timeout(dlm->migration_wq,
2801 dlm_migration_can_proceed(dlm, res, target),
2802 msecs_to_jiffies(1000));
2803 if (ret < 0) {
2804 mlog(0, "woken again: migrating? %s, dead? %s\n",
2805 res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
2806 test_bit(target, dlm->domain_map) ? "no":"yes");
2807 } else {
2808 mlog(0, "all is well: migrating? %s, dead? %s\n",
2809 res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
2810 test_bit(target, dlm->domain_map) ? "no":"yes");
2811 }
2812 if (!dlm_migration_can_proceed(dlm, res, target)) {
2813 mlog(0, "trying again...\n");
2814 goto again;
2815 }
ddc09c8d
KH		 2816 /* now that we are sure the MIGRATING state is there, drop
2817 * the unneded state which blocked threads trying to DIRTY */
2818 spin_lock(&res->spinlock);
2819 BUG_ON(!(res->state & DLM_LOCK_RES_BLOCK_DIRTY));
2820 BUG_ON(!(res->state & DLM_LOCK_RES_MIGRATING));
2821 res->state &= ~DLM_LOCK_RES_BLOCK_DIRTY;
2822 spin_unlock(&res->spinlock);
6714d8e8
KH		 2823
2824 /* did the target go down or die? */
2825 spin_lock(&dlm->spinlock);
2826 if (!test_bit(target, dlm->domain_map)) {
2827 mlog(ML_ERROR, "aha. migration target %u just went down\n",
2828 target);
2829 ret = -EHOSTDOWN;
2830 }
2831 spin_unlock(&dlm->spinlock);
2832
2833 /*
2834 * at this point:
2835 *
2836 * o the DLM_LOCK_RES_MIGRATING flag is set
2837 * o there are no pending asts on this lockres
2838 * o all processes trying to reserve an ast on this
2839 * lockres must wait for the MIGRATING flag to clear
2840 */
2841 return ret;
2842}
2843
2844/* last step in the migration process.
2845 * original master calls this to free all of the dlm_lock
2846 * structures that used to be for other nodes. */
2847static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
2848 struct dlm_lock_resource *res)
2849{
6714d8e8 2850 struct list_head *queue = &res->granted;
ba2bf218 2851 int i, bit;
800deef3 2852 struct dlm_lock *lock, *next;
6714d8e8
KH		 2853
2854 assert_spin_locked(&res->spinlock);
2855
2856 BUG_ON(res->owner == dlm->node_num);
2857
2858 for (i=0; i<3; i++) {
800deef3 2859 list_for_each_entry_safe(lock, next, queue, list) {
6714d8e8
KH		 2860 if (lock->ml.node != dlm->node_num) {
2861 mlog(0, "putting lock for node %u\n",
2862 lock->ml.node);
2863 /* be extra careful */
2864 BUG_ON(!list_empty(&lock->ast_list));
2865 BUG_ON(!list_empty(&lock->bast_list));
2866 BUG_ON(lock->ast_pending);
2867 BUG_ON(lock->bast_pending);
ba2bf218 2868 dlm_lockres_clear_refmap_bit(lock->ml.node, res);
6714d8e8
KH		 2869 list_del_init(&lock->list);
2870 dlm_lock_put(lock);
2c5c54ac
SM		 2871 /* In a normal unlock, we would have added a
2872 * DLM_UNLOCK_FREE_LOCK action. Force it. */
2873 dlm_lock_put(lock);
6714d8e8
KH		 2874 }
2875 }
2876 queue++;
2877 }
ba2bf218
KH		 2878 bit = 0;
2879 while (1) {
2880 bit = find_next_bit(res->refmap, O2NM_MAX_NODES, bit);
2881 if (bit >= O2NM_MAX_NODES)
2882 break;
2883 /* do not clear the local node reference, if there is a
2884 * process holding this, let it drop the ref itself */
2885 if (bit != dlm->node_num) {
2886 mlog(0, "%s:%.*s: node %u had a ref to this "
2887 "migrating lockres, clearing\n", dlm->name,
2888 res->lockname.len, res->lockname.name, bit);
2889 dlm_lockres_clear_refmap_bit(bit, res);
2890 }
2891 bit++;
2892 }
6714d8e8
KH		 2893}
2894
2895/* for now this is not too intelligent. we will
2896 * need stats to make this do the right thing.
2897 * this just finds the first lock on one of the
2898 * queues and uses that node as the target. */
2899static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
2900 struct dlm_lock_resource *res)
2901{
2902 int i;
2903 struct list_head *queue = &res->granted;
6714d8e8
KH		 2904 struct dlm_lock *lock;
2905 int nodenum;
2906
2907 assert_spin_locked(&dlm->spinlock);
2908
2909 spin_lock(&res->spinlock);
2910 for (i=0; i<3; i++) {
800deef3 2911 list_for_each_entry(lock, queue, list) {
6714d8e8
KH		 2912 /* up to the caller to make sure this node
2913 * is alive */
6714d8e8
KH		 2914 if (lock->ml.node != dlm->node_num) {
2915 spin_unlock(&res->spinlock);
2916 return lock->ml.node;
2917 }
2918 }
2919 queue++;
2920 }
2921 spin_unlock(&res->spinlock);
2922 mlog(0, "have not found a suitable target yet! checking domain map\n");
2923
2924 /* ok now we're getting desperate. pick anyone alive. */
2925 nodenum = -1;
2926 while (1) {
2927 nodenum = find_next_bit(dlm->domain_map,
2928 O2NM_MAX_NODES, nodenum+1);
2929 mlog(0, "found %d in domain map\n", nodenum);
2930 if (nodenum >= O2NM_MAX_NODES)
2931 break;
2932 if (nodenum != dlm->node_num) {
2933 mlog(0, "picking %d\n", nodenum);
2934 return nodenum;
2935 }
2936 }
2937
2938 mlog(0, "giving up. no master to migrate to\n");
2939 return DLM_LOCK_RES_OWNER_UNKNOWN;
2940}
2941
2942
2943
2944/* this is called by the new master once all lockres
2945 * data has been received */
2946static int dlm_do_migrate_request(struct dlm_ctxt *dlm,
2947 struct dlm_lock_resource *res,
2948 u8 master, u8 new_master,
2949 struct dlm_node_iter *iter)
2950{
2951 struct dlm_migrate_request migrate;
2952 int ret, status = 0;
2953 int nodenum;
2954
2955 memset(&migrate, 0, sizeof(migrate));
2956 migrate.namelen = res->lockname.len;
2957 memcpy(migrate.name, res->lockname.name, migrate.namelen);
2958 migrate.new_master = new_master;
2959 migrate.master = master;
2960
2961 ret = 0;
2962
2963 /* send message to all nodes, except the master and myself */
2964 while ((nodenum = dlm_node_iter_next(iter)) >= 0) {
2965 if (nodenum == master ||
2966 nodenum == new_master)
2967 continue;
2968
2969 ret = o2net_send_message(DLM_MIGRATE_REQUEST_MSG, dlm->key,
2970 &migrate, sizeof(migrate), nodenum,
2971 &status);
2972 if (ret < 0)
2973 mlog_errno(ret);
2974 else if (status < 0) {
2975 mlog(0, "migrate request (node %u) returned %d!\n",
2976 nodenum, status);
2977 ret = status;
ba2bf218
KH		 2978 } else if (status == DLM_MIGRATE_RESPONSE_MASTERY_REF) {
2979 /* during the migration request we short-circuited
2980 * the mastery of the lockres. make sure we have
2981 * a mastery ref for nodenum */
2982 mlog(0, "%s:%.*s: need ref for node %u\n",
2983 dlm->name, res->lockname.len, res->lockname.name,
2984 nodenum);
2985 spin_lock(&res->spinlock);
2986 dlm_lockres_set_refmap_bit(nodenum, res);
2987 spin_unlock(&res->spinlock);
6714d8e8
KH		 2988 }
2989 }
2990
2991 if (ret < 0)
2992 mlog_errno(ret);
2993
2994 mlog(0, "returning ret=%d\n", ret);
2995 return ret;
2996}
2997
2998
2999/* if there is an existing mle for this lockres, we now know who the master is.
3000 * (the one who sent us *this* message) we can clear it up right away.
3001 * since the process that put the mle on the list still has a reference to it,
3002 * we can unhash it now, set the master and wake the process. as a result,
3003 * we will have no mle in the list to start with. now we can add an mle for
3004 * the migration and this should be the only one found for those scanning the
3005 * list. */
d74c9803
KH		 3006int dlm_migrate_request_handler(struct o2net_msg *msg, u32 len, void *data,
3007 void **ret_data)
6714d8e8
KH		 3008{
3009 struct dlm_ctxt *dlm = data;
3010 struct dlm_lock_resource *res = NULL;
3011 struct dlm_migrate_request *migrate = (struct dlm_migrate_request *) msg->buf;
3012 struct dlm_master_list_entry *mle = NULL, *oldmle = NULL;
3013 const char *name;
a3d33291 3014 unsigned int namelen, hash;
6714d8e8
KH		 3015 int ret = 0;
3016
3017 if (!dlm_grab(dlm))
3018 return -EINVAL;
3019
3020 name = migrate->name;
3021 namelen = migrate->namelen;
a3d33291 3022 hash = dlm_lockid_hash(name, namelen);
6714d8e8
KH		 3023
3024 /* preallocate.. if this fails, abort */
3025 mle = (struct dlm_master_list_entry *) kmem_cache_alloc(dlm_mle_cache,
ad8100e0 3026 GFP_NOFS);
6714d8e8
KH		 3027
3028 if (!mle) {
3029 ret = -ENOMEM;
3030 goto leave;
3031 }
3032
3033 /* check for pre-existing lock */
3034 spin_lock(&dlm->spinlock);
a3d33291 3035 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
6714d8e8
KH		 3036 spin_lock(&dlm->master_lock);
3037
3038 if (res) {
3039 spin_lock(&res->spinlock);
3040 if (res->state & DLM_LOCK_RES_RECOVERING) {
3041 /* if all is working ok, this can only mean that we got
3042 * a migrate request from a node that we now see as
3043 * dead. what can we do here? drop it to the floor? */
3044 spin_unlock(&res->spinlock);
3045 mlog(ML_ERROR, "Got a migrate request, but the "
3046 "lockres is marked as recovering!");
3047 kmem_cache_free(dlm_mle_cache, mle);
3048 ret = -EINVAL; /* need a better solution */
3049 goto unlock;
3050 }
3051 res->state |= DLM_LOCK_RES_MIGRATING;
3052 spin_unlock(&res->spinlock);
3053 }
3054
3055 /* ignore status. only nonzero status would BUG. */
3056 ret = dlm_add_migration_mle(dlm, res, mle, &oldmle,
3057 name, namelen,
3058 migrate->new_master,
3059 migrate->master);
3060
3061unlock:
3062 spin_unlock(&dlm->master_lock);
3063 spin_unlock(&dlm->spinlock);
3064
3065 if (oldmle) {
3066 /* master is known, detach if not already detached */
3067 dlm_mle_detach_hb_events(dlm, oldmle);
3068 dlm_put_mle(oldmle);
3069 }
3070
3071 if (res)
3072 dlm_lockres_put(res);
3073leave:
3074 dlm_put(dlm);
3075 return ret;
3076}
3077
3078/* must be holding dlm->spinlock and dlm->master_lock
3079 * when adding a migration mle, we can clear any other mles
3080 * in the master list because we know with certainty that
3081 * the master is "master". so we remove any old mle from
3082 * the list after setting it's master field, and then add
3083 * the new migration mle. this way we can hold with the rule
3084 * of having only one mle for a given lock name at all times. */
3085static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
3086 struct dlm_lock_resource *res,
3087 struct dlm_master_list_entry *mle,
3088 struct dlm_master_list_entry **oldmle,
3089 const char *name, unsigned int namelen,
3090 u8 new_master, u8 master)
3091{
3092 int found;
3093 int ret = 0;
3094
3095 *oldmle = NULL;
3096
3097 mlog_entry_void();
3098
3099 assert_spin_locked(&dlm->spinlock);
3100 assert_spin_locked(&dlm->master_lock);
3101
3102 /* caller is responsible for any ref taken here on oldmle */
3103 found = dlm_find_mle(dlm, oldmle, (char *)name, namelen);
3104 if (found) {
3105 struct dlm_master_list_entry *tmp = *oldmle;
3106 spin_lock(&tmp->spinlock);
3107 if (tmp->type == DLM_MLE_MIGRATION) {
3108 if (master == dlm->node_num) {
3109 /* ah another process raced me to it */
3110 mlog(0, "tried to migrate %.*s, but some "
3111 "process beat me to it\n",
3112 namelen, name);
3113 ret = -EEXIST;
3114 } else {
3115 /* bad. 2 NODES are trying to migrate! */
3116 mlog(ML_ERROR, "migration error mle: "
3117 "master=%u new_master=%u // request: "
3118 "master=%u new_master=%u // "
3119 "lockres=%.*s\n",
3120 tmp->master, tmp->new_master,
3121 master, new_master,
3122 namelen, name);
3123 BUG();
3124 }
3125 } else {
3126 /* this is essentially what assert_master does */
3127 tmp->master = master;
3128 atomic_set(&tmp->woken, 1);
3129 wake_up(&tmp->wq);
3130 /* remove it from the list so that only one
3131 * mle will be found */
3132 list_del_init(&tmp->list);
ba2bf218
KH		 3133 /* this was obviously WRONG. mle is uninited here. should be tmp. */
3134 __dlm_mle_detach_hb_events(dlm, tmp);
3135 ret = DLM_MIGRATE_RESPONSE_MASTERY_REF;
3136 mlog(0, "%s:%.*s: master=%u, newmaster=%u, "
3137 "telling master to get ref for cleared out mle "
3138 "during migration\n", dlm->name, namelen, name,
3139 master, new_master);
6714d8e8
KH		 3140 }
3141 spin_unlock(&tmp->spinlock);
3142 }
3143
3144 /* now add a migration mle to the tail of the list */
3145 dlm_init_mle(mle, DLM_MLE_MIGRATION, dlm, res, name, namelen);
3146 mle->new_master = new_master;
ba2bf218
KH		 3147 /* the new master will be sending an assert master for this.
3148 * at that point we will get the refmap reference */
6714d8e8
KH		 3149 mle->master = master;
3150 /* do this for consistency with other mle types */
3151 set_bit(new_master, mle->maybe_map);
3152 list_add(&mle->list, &dlm->master_list);
3153
3154 return ret;
3155}
3156
3157
3158void dlm_clean_master_list(struct dlm_ctxt *dlm, u8 dead_node)
3159{
800deef3 3160 struct dlm_master_list_entry *mle, *next;
6714d8e8 3161 struct dlm_lock_resource *res;
a3d33291 3162 unsigned int hash;
6714d8e8
KH		 3163
3164 mlog_entry("dlm=%s, dead node=%u\n", dlm->name, dead_node);
3165top:
3166 assert_spin_locked(&dlm->spinlock);
3167
3168 /* clean the master list */
3169 spin_lock(&dlm->master_lock);
800deef3 3170 list_for_each_entry_safe(mle, next, &dlm->master_list, list) {
6714d8e8
KH		 3171 BUG_ON(mle->type != DLM_MLE_BLOCK &&
3172 mle->type != DLM_MLE_MASTER &&
3173 mle->type != DLM_MLE_MIGRATION);
3174
3175 /* MASTER mles are initiated locally. the waiting
3176 * process will notice the node map change
3177 * shortly. let that happen as normal. */
3178 if (mle->type == DLM_MLE_MASTER)
3179 continue;
3180
3181
3182 /* BLOCK mles are initiated by other nodes.
3183 * need to clean up if the dead node would have
3184 * been the master. */
3185 if (mle->type == DLM_MLE_BLOCK) {
3186 int bit;
3187
3188 spin_lock(&mle->spinlock);
3189 bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
3190 if (bit != dead_node) {
3191 mlog(0, "mle found, but dead node %u would "
3192 "not have been master\n", dead_node);
3193 spin_unlock(&mle->spinlock);
3194 } else {
3195 /* must drop the refcount by one since the
3196 * assert_master will never arrive. this
3197 * may result in the mle being unlinked and
3198 * freed, but there may still be a process
3199 * waiting in the dlmlock path which is fine. */
3b3b84a8 3200 mlog(0, "node %u was expected master\n",
6714d8e8
KH		 3201 dead_node);
3202 atomic_set(&mle->woken, 1);
3203 spin_unlock(&mle->spinlock);
3204 wake_up(&mle->wq);
f671c09b
KH		 3205 /* do not need events any longer, so detach
3206 * from heartbeat */
3207 __dlm_mle_detach_hb_events(dlm, mle);
6714d8e8
KH		 3208 __dlm_put_mle(mle);
3209 }
3210 continue;
3211 }
3212
3213 /* everything else is a MIGRATION mle */
3214
3215 /* the rule for MIGRATION mles is that the master
3216 * becomes UNKNOWN if *either* the original or
3217 * the new master dies. all UNKNOWN lockreses
3218 * are sent to whichever node becomes the recovery
3219 * master. the new master is responsible for
3220 * determining if there is still a master for
3221 * this lockres, or if he needs to take over
3222 * mastery. either way, this node should expect
3223 * another message to resolve this. */
3224 if (mle->master != dead_node &&
3225 mle->new_master != dead_node)
3226 continue;
3227
3228 /* if we have reached this point, this mle needs to
3229 * be removed from the list and freed. */
3230
3231 /* remove from the list early. NOTE: unlinking
3232 * list_head while in list_for_each_safe */
da01ad05 3233 __dlm_mle_detach_hb_events(dlm, mle);
6714d8e8
KH		 3234 spin_lock(&mle->spinlock);
3235 list_del_init(&mle->list);
3236 atomic_set(&mle->woken, 1);
3237 spin_unlock(&mle->spinlock);
3238 wake_up(&mle->wq);
3239
aa852354
KH		 3240 mlog(0, "%s: node %u died during migration from "
3241 "%u to %u!\n", dlm->name, dead_node,
6714d8e8
KH		 3242 mle->master, mle->new_master);
3243 /* if there is a lockres associated with this
3244 * mle, find it and set its owner to UNKNOWN */
a3d33291 3245 hash = dlm_lockid_hash(mle->u.name.name, mle->u.name.len);
6714d8e8 3246 res = __dlm_lookup_lockres(dlm, mle->u.name.name,
a3d33291 3247 mle->u.name.len, hash);
6714d8e8
KH		 3248 if (res) {
3249 /* unfortunately if we hit this rare case, our
3250 * lock ordering is messed. we need to drop
3251 * the master lock so that we can take the
3252 * lockres lock, meaning that we will have to
3253 * restart from the head of list. */
3254 spin_unlock(&dlm->master_lock);
3255
3256 /* move lockres onto recovery list */
3257 spin_lock(&res->spinlock);
3258 dlm_set_lockres_owner(dlm, res,
3259 DLM_LOCK_RES_OWNER_UNKNOWN);
3260 dlm_move_lockres_to_recovery_list(dlm, res);
3261 spin_unlock(&res->spinlock);
3262 dlm_lockres_put(res);
3263
f671c09b
KH		 3264 /* about to get rid of mle, detach from heartbeat */
3265 __dlm_mle_detach_hb_events(dlm, mle);
3266
6714d8e8
KH		 3267 /* dump the mle */
3268 spin_lock(&dlm->master_lock);
3269 __dlm_put_mle(mle);
3270 spin_unlock(&dlm->master_lock);
3271
3272 /* restart */
3273 goto top;
3274 }
3275
3276 /* this may be the last reference */
3277 __dlm_put_mle(mle);
3278 }
3279 spin_unlock(&dlm->master_lock);
3280}
3281
3282
3283int dlm_finish_migration(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
3284 u8 old_master)
3285{
3286 struct dlm_node_iter iter;
3287 int ret = 0;
3288
3289 spin_lock(&dlm->spinlock);
3290 dlm_node_iter_init(dlm->domain_map, &iter);
3291 clear_bit(old_master, iter.node_map);
3292 clear_bit(dlm->node_num, iter.node_map);
3293 spin_unlock(&dlm->spinlock);
3294
ba2bf218
KH		 3295 /* ownership of the lockres is changing. account for the
3296 * mastery reference here since old_master will briefly have
3297 * a reference after the migration completes */
3298 spin_lock(&res->spinlock);
3299 dlm_lockres_set_refmap_bit(old_master, res);
3300 spin_unlock(&res->spinlock);
3301
6714d8e8
KH		 3302 mlog(0, "now time to do a migrate request to other nodes\n");
3303 ret = dlm_do_migrate_request(dlm, res, old_master,
3304 dlm->node_num, &iter);
3305 if (ret < 0) {
3306 mlog_errno(ret);
3307 goto leave;
3308 }
3309
3310 mlog(0, "doing assert master of %.*s to all except the original node\n",
3311 res->lockname.len, res->lockname.name);
3312 /* this call now finishes out the nodemap
3313 * even if one or more nodes die */
ba2bf218 3314 ret = dlm_do_assert_master(dlm, res, iter.node_map,
6714d8e8
KH		 3315 DLM_ASSERT_MASTER_FINISH_MIGRATION);
3316 if (ret < 0) {
3317 /* no longer need to retry. all living nodes contacted. */
3318 mlog_errno(ret);
3319 ret = 0;
3320 }
3321
3322 memset(iter.node_map, 0, sizeof(iter.node_map));
3323 set_bit(old_master, iter.node_map);
3324 mlog(0, "doing assert master of %.*s back to %u\n",
3325 res->lockname.len, res->lockname.name, old_master);
ba2bf218 3326 ret = dlm_do_assert_master(dlm, res, iter.node_map,
6714d8e8
KH		 3327 DLM_ASSERT_MASTER_FINISH_MIGRATION);
3328 if (ret < 0) {
3329 mlog(0, "assert master to original master failed "
3330 "with %d.\n", ret);
3331 /* the only nonzero status here would be because of
3332 * a dead original node. we're done. */
3333 ret = 0;
3334 }
3335
3336 /* all done, set the owner, clear the flag */
3337 spin_lock(&res->spinlock);
3338 dlm_set_lockres_owner(dlm, res, dlm->node_num);
3339 res->state &= ~DLM_LOCK_RES_MIGRATING;
3340 spin_unlock(&res->spinlock);
3341 /* re-dirty it on the new master */
3342 dlm_kick_thread(dlm, res);
3343 wake_up(&res->wq);
3344leave:
3345 return ret;
3346}
3347
3348/*
3349 * LOCKRES AST REFCOUNT
3350 * this is integral to migration
3351 */
3352
3353/* for future intent to call an ast, reserve one ahead of time.
3354 * this should be called only after waiting on the lockres
3355 * with dlm_wait_on_lockres, and while still holding the
3356 * spinlock after the call. */
3357void __dlm_lockres_reserve_ast(struct dlm_lock_resource *res)
3358{
3359 assert_spin_locked(&res->spinlock);
3360 if (res->state & DLM_LOCK_RES_MIGRATING) {
3361 __dlm_print_one_lock_resource(res);
3362 }
3363 BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
3364
3365 atomic_inc(&res->asts_reserved);
3366}
3367
3368/*
3369 * used to drop the reserved ast, either because it went unused,
3370 * or because the ast/bast was actually called.
3371 *
3372 * also, if there is a pending migration on this lockres,
3373 * and this was the last pending ast on the lockres,
3374 * atomically set the MIGRATING flag before we drop the lock.
3375 * this is how we ensure that migration can proceed with no
3376 * asts in progress. note that it is ok if the state of the
3377 * queues is such that a lock should be granted in the future
3378 * or that a bast should be fired, because the new master will
3379 * shuffle the lists on this lockres as soon as it is migrated.
3380 */
3381void dlm_lockres_release_ast(struct dlm_ctxt *dlm,
3382 struct dlm_lock_resource *res)
3383{
3384 if (!atomic_dec_and_lock(&res->asts_reserved, &res->spinlock))
3385 return;
3386
3387 if (!res->migration_pending) {
3388 spin_unlock(&res->spinlock);
3389 return;
3390 }
3391
3392 BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
3393 res->migration_pending = 0;
3394 res->state |= DLM_LOCK_RES_MIGRATING;
3395 spin_unlock(&res->spinlock);
3396 wake_up(&res->wq);
3397 wake_up(&dlm->migration_wq);
3398}
Linux 6.x block layer and io_uring tree(s)