Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
[cris-mirror.git] / fs / ocfs2 / dlm / dlmmaster.c
bloba7df226f944946be1f70fa24fc2de76cb573a5f2
1 /* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
4 * dlmmod.c
6 * standalone DLM module
8 * Copyright (C) 2004 Oracle. All rights reserved.
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.
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.
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.
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/init.h>
34 #include <linux/sysctl.h>
35 #include <linux/random.h>
36 #include <linux/blkdev.h>
37 #include <linux/socket.h>
38 #include <linux/inet.h>
39 #include <linux/spinlock.h>
40 #include <linux/delay.h>
43 #include "cluster/heartbeat.h"
44 #include "cluster/nodemanager.h"
45 #include "cluster/tcp.h"
47 #include "dlmapi.h"
48 #include "dlmcommon.h"
49 #include "dlmdomain.h"
50 #include "dlmdebug.h"
52 #define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_MASTER)
53 #include "cluster/masklog.h"
55 static void dlm_mle_node_down(struct dlm_ctxt *dlm,
56 struct dlm_master_list_entry *mle,
57 struct o2nm_node *node,
58 int idx);
59 static void dlm_mle_node_up(struct dlm_ctxt *dlm,
60 struct dlm_master_list_entry *mle,
61 struct o2nm_node *node,
62 int idx);
64 static void dlm_assert_master_worker(struct dlm_work_item *item, void *data);
65 static int dlm_do_assert_master(struct dlm_ctxt *dlm,
66 struct dlm_lock_resource *res,
67 void *nodemap, u32 flags);
68 static void dlm_deref_lockres_worker(struct dlm_work_item *item, void *data);
70 static inline int dlm_mle_equal(struct dlm_ctxt *dlm,
71 struct dlm_master_list_entry *mle,
72 const char *name,
73 unsigned int namelen)
75 if (dlm != mle->dlm)
76 return 0;
78 if (namelen != mle->mnamelen ||
79 memcmp(name, mle->mname, namelen) != 0)
80 return 0;
82 return 1;
85 static struct kmem_cache *dlm_lockres_cache;
86 static struct kmem_cache *dlm_lockname_cache;
87 static struct kmem_cache *dlm_mle_cache;
89 static void dlm_mle_release(struct kref *kref);
90 static void dlm_init_mle(struct dlm_master_list_entry *mle,
91 enum dlm_mle_type type,
92 struct dlm_ctxt *dlm,
93 struct dlm_lock_resource *res,
94 const char *name,
95 unsigned int namelen);
96 static void dlm_put_mle(struct dlm_master_list_entry *mle);
97 static void __dlm_put_mle(struct dlm_master_list_entry *mle);
98 static int dlm_find_mle(struct dlm_ctxt *dlm,
99 struct dlm_master_list_entry **mle,
100 char *name, unsigned int namelen);
102 static int dlm_do_master_request(struct dlm_lock_resource *res,
103 struct dlm_master_list_entry *mle, int to);
106 static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
107 struct dlm_lock_resource *res,
108 struct dlm_master_list_entry *mle,
109 int *blocked);
110 static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
111 struct dlm_lock_resource *res,
112 struct dlm_master_list_entry *mle,
113 int blocked);
114 static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
115 struct dlm_lock_resource *res,
116 struct dlm_master_list_entry *mle,
117 struct dlm_master_list_entry **oldmle,
118 const char *name, unsigned int namelen,
119 u8 new_master, u8 master);
121 static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
122 struct dlm_lock_resource *res);
123 static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
124 struct dlm_lock_resource *res);
125 static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
126 struct dlm_lock_resource *res,
127 u8 target);
128 static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
129 struct dlm_lock_resource *res);
132 int dlm_is_host_down(int errno)
134 switch (errno) {
135 case -EBADF:
136 case -ECONNREFUSED:
137 case -ENOTCONN:
138 case -ECONNRESET:
139 case -EPIPE:
140 case -EHOSTDOWN:
141 case -EHOSTUNREACH:
142 case -ETIMEDOUT:
143 case -ECONNABORTED:
144 case -ENETDOWN:
145 case -ENETUNREACH:
146 case -ENETRESET:
147 case -ESHUTDOWN:
148 case -ENOPROTOOPT:
149 case -EINVAL: /* if returned from our tcp code,
150 this means there is no socket */
151 return 1;
153 return 0;
158 * MASTER LIST FUNCTIONS
163 * regarding master list entries and heartbeat callbacks:
165 * in order to avoid sleeping and allocation that occurs in
166 * heartbeat, master list entries are simply attached to the
167 * dlm's established heartbeat callbacks. the mle is attached
168 * when it is created, and since the dlm->spinlock is held at
169 * that time, any heartbeat event will be properly discovered
170 * by the mle. the mle needs to be detached from the
171 * dlm->mle_hb_events list as soon as heartbeat events are no
172 * longer useful to the mle, and before the mle is freed.
174 * as a general rule, heartbeat events are no longer needed by
175 * the mle once an "answer" regarding the lock master has been
176 * received.
178 static inline void __dlm_mle_attach_hb_events(struct dlm_ctxt *dlm,
179 struct dlm_master_list_entry *mle)
181 assert_spin_locked(&dlm->spinlock);
183 list_add_tail(&mle->hb_events, &dlm->mle_hb_events);
187 static inline void __dlm_mle_detach_hb_events(struct dlm_ctxt *dlm,
188 struct dlm_master_list_entry *mle)
190 if (!list_empty(&mle->hb_events))
191 list_del_init(&mle->hb_events);
195 static inline void dlm_mle_detach_hb_events(struct dlm_ctxt *dlm,
196 struct dlm_master_list_entry *mle)
198 spin_lock(&dlm->spinlock);
199 __dlm_mle_detach_hb_events(dlm, mle);
200 spin_unlock(&dlm->spinlock);
203 static void dlm_get_mle_inuse(struct dlm_master_list_entry *mle)
205 struct dlm_ctxt *dlm;
206 dlm = mle->dlm;
208 assert_spin_locked(&dlm->spinlock);
209 assert_spin_locked(&dlm->master_lock);
210 mle->inuse++;
211 kref_get(&mle->mle_refs);
214 static void dlm_put_mle_inuse(struct dlm_master_list_entry *mle)
216 struct dlm_ctxt *dlm;
217 dlm = mle->dlm;
219 spin_lock(&dlm->spinlock);
220 spin_lock(&dlm->master_lock);
221 mle->inuse--;
222 __dlm_put_mle(mle);
223 spin_unlock(&dlm->master_lock);
224 spin_unlock(&dlm->spinlock);
228 /* remove from list and free */
229 static void __dlm_put_mle(struct dlm_master_list_entry *mle)
231 struct dlm_ctxt *dlm;
232 dlm = mle->dlm;
234 assert_spin_locked(&dlm->spinlock);
235 assert_spin_locked(&dlm->master_lock);
236 if (!kref_read(&mle->mle_refs)) {
237 /* this may or may not crash, but who cares.
238 * it's a BUG. */
239 mlog(ML_ERROR, "bad mle: %p\n", mle);
240 dlm_print_one_mle(mle);
241 BUG();
242 } else
243 kref_put(&mle->mle_refs, dlm_mle_release);
247 /* must not have any spinlocks coming in */
248 static void dlm_put_mle(struct dlm_master_list_entry *mle)
250 struct dlm_ctxt *dlm;
251 dlm = mle->dlm;
253 spin_lock(&dlm->spinlock);
254 spin_lock(&dlm->master_lock);
255 __dlm_put_mle(mle);
256 spin_unlock(&dlm->master_lock);
257 spin_unlock(&dlm->spinlock);
260 static inline void dlm_get_mle(struct dlm_master_list_entry *mle)
262 kref_get(&mle->mle_refs);
265 static void dlm_init_mle(struct dlm_master_list_entry *mle,
266 enum dlm_mle_type type,
267 struct dlm_ctxt *dlm,
268 struct dlm_lock_resource *res,
269 const char *name,
270 unsigned int namelen)
272 assert_spin_locked(&dlm->spinlock);
274 mle->dlm = dlm;
275 mle->type = type;
276 INIT_HLIST_NODE(&mle->master_hash_node);
277 INIT_LIST_HEAD(&mle->hb_events);
278 memset(mle->maybe_map, 0, sizeof(mle->maybe_map));
279 spin_lock_init(&mle->spinlock);
280 init_waitqueue_head(&mle->wq);
281 atomic_set(&mle->woken, 0);
282 kref_init(&mle->mle_refs);
283 memset(mle->response_map, 0, sizeof(mle->response_map));
284 mle->master = O2NM_MAX_NODES;
285 mle->new_master = O2NM_MAX_NODES;
286 mle->inuse = 0;
288 BUG_ON(mle->type != DLM_MLE_BLOCK &&
289 mle->type != DLM_MLE_MASTER &&
290 mle->type != DLM_MLE_MIGRATION);
292 if (mle->type == DLM_MLE_MASTER) {
293 BUG_ON(!res);
294 mle->mleres = res;
295 memcpy(mle->mname, res->lockname.name, res->lockname.len);
296 mle->mnamelen = res->lockname.len;
297 mle->mnamehash = res->lockname.hash;
298 } else {
299 BUG_ON(!name);
300 mle->mleres = NULL;
301 memcpy(mle->mname, name, namelen);
302 mle->mnamelen = namelen;
303 mle->mnamehash = dlm_lockid_hash(name, namelen);
306 atomic_inc(&dlm->mle_tot_count[mle->type]);
307 atomic_inc(&dlm->mle_cur_count[mle->type]);
309 /* copy off the node_map and register hb callbacks on our copy */
310 memcpy(mle->node_map, dlm->domain_map, sizeof(mle->node_map));
311 memcpy(mle->vote_map, dlm->domain_map, sizeof(mle->vote_map));
312 clear_bit(dlm->node_num, mle->vote_map);
313 clear_bit(dlm->node_num, mle->node_map);
315 /* attach the mle to the domain node up/down events */
316 __dlm_mle_attach_hb_events(dlm, mle);
319 void __dlm_unlink_mle(struct dlm_ctxt *dlm, struct dlm_master_list_entry *mle)
321 assert_spin_locked(&dlm->spinlock);
322 assert_spin_locked(&dlm->master_lock);
324 if (!hlist_unhashed(&mle->master_hash_node))
325 hlist_del_init(&mle->master_hash_node);
328 void __dlm_insert_mle(struct dlm_ctxt *dlm, struct dlm_master_list_entry *mle)
330 struct hlist_head *bucket;
332 assert_spin_locked(&dlm->master_lock);
334 bucket = dlm_master_hash(dlm, mle->mnamehash);
335 hlist_add_head(&mle->master_hash_node, bucket);
338 /* returns 1 if found, 0 if not */
339 static int dlm_find_mle(struct dlm_ctxt *dlm,
340 struct dlm_master_list_entry **mle,
341 char *name, unsigned int namelen)
343 struct dlm_master_list_entry *tmpmle;
344 struct hlist_head *bucket;
345 unsigned int hash;
347 assert_spin_locked(&dlm->master_lock);
349 hash = dlm_lockid_hash(name, namelen);
350 bucket = dlm_master_hash(dlm, hash);
351 hlist_for_each_entry(tmpmle, bucket, master_hash_node) {
352 if (!dlm_mle_equal(dlm, tmpmle, name, namelen))
353 continue;
354 dlm_get_mle(tmpmle);
355 *mle = tmpmle;
356 return 1;
358 return 0;
361 void dlm_hb_event_notify_attached(struct dlm_ctxt *dlm, int idx, int node_up)
363 struct dlm_master_list_entry *mle;
365 assert_spin_locked(&dlm->spinlock);
367 list_for_each_entry(mle, &dlm->mle_hb_events, hb_events) {
368 if (node_up)
369 dlm_mle_node_up(dlm, mle, NULL, idx);
370 else
371 dlm_mle_node_down(dlm, mle, NULL, idx);
375 static void dlm_mle_node_down(struct dlm_ctxt *dlm,
376 struct dlm_master_list_entry *mle,
377 struct o2nm_node *node, int idx)
379 spin_lock(&mle->spinlock);
381 if (!test_bit(idx, mle->node_map))
382 mlog(0, "node %u already removed from nodemap!\n", idx);
383 else
384 clear_bit(idx, mle->node_map);
386 spin_unlock(&mle->spinlock);
389 static void dlm_mle_node_up(struct dlm_ctxt *dlm,
390 struct dlm_master_list_entry *mle,
391 struct o2nm_node *node, int idx)
393 spin_lock(&mle->spinlock);
395 if (test_bit(idx, mle->node_map))
396 mlog(0, "node %u already in node map!\n", idx);
397 else
398 set_bit(idx, mle->node_map);
400 spin_unlock(&mle->spinlock);
404 int dlm_init_mle_cache(void)
406 dlm_mle_cache = kmem_cache_create("o2dlm_mle",
407 sizeof(struct dlm_master_list_entry),
408 0, SLAB_HWCACHE_ALIGN,
409 NULL);
410 if (dlm_mle_cache == NULL)
411 return -ENOMEM;
412 return 0;
415 void dlm_destroy_mle_cache(void)
417 if (dlm_mle_cache)
418 kmem_cache_destroy(dlm_mle_cache);
421 static void dlm_mle_release(struct kref *kref)
423 struct dlm_master_list_entry *mle;
424 struct dlm_ctxt *dlm;
426 mle = container_of(kref, struct dlm_master_list_entry, mle_refs);
427 dlm = mle->dlm;
429 assert_spin_locked(&dlm->spinlock);
430 assert_spin_locked(&dlm->master_lock);
432 mlog(0, "Releasing mle for %.*s, type %d\n", mle->mnamelen, mle->mname,
433 mle->type);
435 /* remove from list if not already */
436 __dlm_unlink_mle(dlm, mle);
438 /* detach the mle from the domain node up/down events */
439 __dlm_mle_detach_hb_events(dlm, mle);
441 atomic_dec(&dlm->mle_cur_count[mle->type]);
443 /* NOTE: kfree under spinlock here.
444 * if this is bad, we can move this to a freelist. */
445 kmem_cache_free(dlm_mle_cache, mle);
450 * LOCK RESOURCE FUNCTIONS
453 int dlm_init_master_caches(void)
455 dlm_lockres_cache = kmem_cache_create("o2dlm_lockres",
456 sizeof(struct dlm_lock_resource),
457 0, SLAB_HWCACHE_ALIGN, NULL);
458 if (!dlm_lockres_cache)
459 goto bail;
461 dlm_lockname_cache = kmem_cache_create("o2dlm_lockname",
462 DLM_LOCKID_NAME_MAX, 0,
463 SLAB_HWCACHE_ALIGN, NULL);
464 if (!dlm_lockname_cache)
465 goto bail;
467 return 0;
468 bail:
469 dlm_destroy_master_caches();
470 return -ENOMEM;
473 void dlm_destroy_master_caches(void)
475 if (dlm_lockname_cache) {
476 kmem_cache_destroy(dlm_lockname_cache);
477 dlm_lockname_cache = NULL;
480 if (dlm_lockres_cache) {
481 kmem_cache_destroy(dlm_lockres_cache);
482 dlm_lockres_cache = NULL;
486 static void dlm_lockres_release(struct kref *kref)
488 struct dlm_lock_resource *res;
489 struct dlm_ctxt *dlm;
491 res = container_of(kref, struct dlm_lock_resource, refs);
492 dlm = res->dlm;
494 /* This should not happen -- all lockres' have a name
495 * associated with them at init time. */
496 BUG_ON(!res->lockname.name);
498 mlog(0, "destroying lockres %.*s\n", res->lockname.len,
499 res->lockname.name);
501 atomic_dec(&dlm->res_cur_count);
503 if (!hlist_unhashed(&res->hash_node) ||
504 !list_empty(&res->granted) ||
505 !list_empty(&res->converting) ||
506 !list_empty(&res->blocked) ||
507 !list_empty(&res->dirty) ||
508 !list_empty(&res->recovering) ||
509 !list_empty(&res->purge)) {
510 mlog(ML_ERROR,
511 "Going to BUG for resource %.*s."
512 " We're on a list! [%c%c%c%c%c%c%c]\n",
513 res->lockname.len, res->lockname.name,
514 !hlist_unhashed(&res->hash_node) ? 'H' : ' ',
515 !list_empty(&res->granted) ? 'G' : ' ',
516 !list_empty(&res->converting) ? 'C' : ' ',
517 !list_empty(&res->blocked) ? 'B' : ' ',
518 !list_empty(&res->dirty) ? 'D' : ' ',
519 !list_empty(&res->recovering) ? 'R' : ' ',
520 !list_empty(&res->purge) ? 'P' : ' ');
522 dlm_print_one_lock_resource(res);
525 /* By the time we're ready to blow this guy away, we shouldn't
526 * be on any lists. */
527 BUG_ON(!hlist_unhashed(&res->hash_node));
528 BUG_ON(!list_empty(&res->granted));
529 BUG_ON(!list_empty(&res->converting));
530 BUG_ON(!list_empty(&res->blocked));
531 BUG_ON(!list_empty(&res->dirty));
532 BUG_ON(!list_empty(&res->recovering));
533 BUG_ON(!list_empty(&res->purge));
535 kmem_cache_free(dlm_lockname_cache, (void *)res->lockname.name);
537 kmem_cache_free(dlm_lockres_cache, res);
540 void dlm_lockres_put(struct dlm_lock_resource *res)
542 kref_put(&res->refs, dlm_lockres_release);
545 static void dlm_init_lockres(struct dlm_ctxt *dlm,
546 struct dlm_lock_resource *res,
547 const char *name, unsigned int namelen)
549 char *qname;
551 /* If we memset here, we lose our reference to the kmalloc'd
552 * res->lockname.name, so be sure to init every field
553 * correctly! */
555 qname = (char *) res->lockname.name;
556 memcpy(qname, name, namelen);
558 res->lockname.len = namelen;
559 res->lockname.hash = dlm_lockid_hash(name, namelen);
561 init_waitqueue_head(&res->wq);
562 spin_lock_init(&res->spinlock);
563 INIT_HLIST_NODE(&res->hash_node);
564 INIT_LIST_HEAD(&res->granted);
565 INIT_LIST_HEAD(&res->converting);
566 INIT_LIST_HEAD(&res->blocked);
567 INIT_LIST_HEAD(&res->dirty);
568 INIT_LIST_HEAD(&res->recovering);
569 INIT_LIST_HEAD(&res->purge);
570 INIT_LIST_HEAD(&res->tracking);
571 atomic_set(&res->asts_reserved, 0);
572 res->migration_pending = 0;
573 res->inflight_locks = 0;
574 res->inflight_assert_workers = 0;
576 res->dlm = dlm;
578 kref_init(&res->refs);
580 atomic_inc(&dlm->res_tot_count);
581 atomic_inc(&dlm->res_cur_count);
583 /* just for consistency */
584 spin_lock(&res->spinlock);
585 dlm_set_lockres_owner(dlm, res, DLM_LOCK_RES_OWNER_UNKNOWN);
586 spin_unlock(&res->spinlock);
588 res->state = DLM_LOCK_RES_IN_PROGRESS;
590 res->last_used = 0;
592 spin_lock(&dlm->spinlock);
593 list_add_tail(&res->tracking, &dlm->tracking_list);
594 spin_unlock(&dlm->spinlock);
596 memset(res->lvb, 0, DLM_LVB_LEN);
597 memset(res->refmap, 0, sizeof(res->refmap));
600 struct dlm_lock_resource *dlm_new_lockres(struct dlm_ctxt *dlm,
601 const char *name,
602 unsigned int namelen)
604 struct dlm_lock_resource *res = NULL;
606 res = kmem_cache_zalloc(dlm_lockres_cache, GFP_NOFS);
607 if (!res)
608 goto error;
610 res->lockname.name = kmem_cache_zalloc(dlm_lockname_cache, GFP_NOFS);
611 if (!res->lockname.name)
612 goto error;
614 dlm_init_lockres(dlm, res, name, namelen);
615 return res;
617 error:
618 if (res)
619 kmem_cache_free(dlm_lockres_cache, res);
620 return NULL;
623 void dlm_lockres_set_refmap_bit(struct dlm_ctxt *dlm,
624 struct dlm_lock_resource *res, int bit)
626 assert_spin_locked(&res->spinlock);
628 mlog(0, "res %.*s, set node %u, %ps()\n", res->lockname.len,
629 res->lockname.name, bit, __builtin_return_address(0));
631 set_bit(bit, res->refmap);
634 void dlm_lockres_clear_refmap_bit(struct dlm_ctxt *dlm,
635 struct dlm_lock_resource *res, int bit)
637 assert_spin_locked(&res->spinlock);
639 mlog(0, "res %.*s, clr node %u, %ps()\n", res->lockname.len,
640 res->lockname.name, bit, __builtin_return_address(0));
642 clear_bit(bit, res->refmap);
645 static void __dlm_lockres_grab_inflight_ref(struct dlm_ctxt *dlm,
646 struct dlm_lock_resource *res)
648 res->inflight_locks++;
650 mlog(0, "%s: res %.*s, inflight++: now %u, %ps()\n", dlm->name,
651 res->lockname.len, res->lockname.name, res->inflight_locks,
652 __builtin_return_address(0));
655 void dlm_lockres_grab_inflight_ref(struct dlm_ctxt *dlm,
656 struct dlm_lock_resource *res)
658 assert_spin_locked(&res->spinlock);
659 __dlm_lockres_grab_inflight_ref(dlm, res);
662 void dlm_lockres_drop_inflight_ref(struct dlm_ctxt *dlm,
663 struct dlm_lock_resource *res)
665 assert_spin_locked(&res->spinlock);
667 BUG_ON(res->inflight_locks == 0);
669 res->inflight_locks--;
671 mlog(0, "%s: res %.*s, inflight--: now %u, %ps()\n", dlm->name,
672 res->lockname.len, res->lockname.name, res->inflight_locks,
673 __builtin_return_address(0));
675 wake_up(&res->wq);
678 void __dlm_lockres_grab_inflight_worker(struct dlm_ctxt *dlm,
679 struct dlm_lock_resource *res)
681 assert_spin_locked(&res->spinlock);
682 res->inflight_assert_workers++;
683 mlog(0, "%s:%.*s: inflight assert worker++: now %u\n",
684 dlm->name, res->lockname.len, res->lockname.name,
685 res->inflight_assert_workers);
688 static void __dlm_lockres_drop_inflight_worker(struct dlm_ctxt *dlm,
689 struct dlm_lock_resource *res)
691 assert_spin_locked(&res->spinlock);
692 BUG_ON(res->inflight_assert_workers == 0);
693 res->inflight_assert_workers--;
694 mlog(0, "%s:%.*s: inflight assert worker--: now %u\n",
695 dlm->name, res->lockname.len, res->lockname.name,
696 res->inflight_assert_workers);
699 static void dlm_lockres_drop_inflight_worker(struct dlm_ctxt *dlm,
700 struct dlm_lock_resource *res)
702 spin_lock(&res->spinlock);
703 __dlm_lockres_drop_inflight_worker(dlm, res);
704 spin_unlock(&res->spinlock);
708 * lookup a lock resource by name.
709 * may already exist in the hashtable.
710 * lockid is null terminated
712 * if not, allocate enough for the lockres and for
713 * the temporary structure used in doing the mastering.
715 * also, do a lookup in the dlm->master_list to see
716 * if another node has begun mastering the same lock.
717 * if so, there should be a block entry in there
718 * for this name, and we should *not* attempt to master
719 * the lock here. need to wait around for that node
720 * to assert_master (or die).
723 struct dlm_lock_resource * dlm_get_lock_resource(struct dlm_ctxt *dlm,
724 const char *lockid,
725 int namelen,
726 int flags)
728 struct dlm_lock_resource *tmpres=NULL, *res=NULL;
729 struct dlm_master_list_entry *mle = NULL;
730 struct dlm_master_list_entry *alloc_mle = NULL;
731 int blocked = 0;
732 int ret, nodenum;
733 struct dlm_node_iter iter;
734 unsigned int hash;
735 int tries = 0;
736 int bit, wait_on_recovery = 0;
738 BUG_ON(!lockid);
740 hash = dlm_lockid_hash(lockid, namelen);
742 mlog(0, "get lockres %s (len %d)\n", lockid, namelen);
744 lookup:
745 spin_lock(&dlm->spinlock);
746 tmpres = __dlm_lookup_lockres_full(dlm, lockid, namelen, hash);
747 if (tmpres) {
748 spin_unlock(&dlm->spinlock);
749 spin_lock(&tmpres->spinlock);
752 * Right after dlm spinlock was released, dlm_thread could have
753 * purged the lockres. Check if lockres got unhashed. If so
754 * start over.
756 if (hlist_unhashed(&tmpres->hash_node)) {
757 spin_unlock(&tmpres->spinlock);
758 dlm_lockres_put(tmpres);
759 tmpres = NULL;
760 goto lookup;
763 /* Wait on the thread that is mastering the resource */
764 if (tmpres->owner == DLM_LOCK_RES_OWNER_UNKNOWN) {
765 __dlm_wait_on_lockres(tmpres);
766 BUG_ON(tmpres->owner == DLM_LOCK_RES_OWNER_UNKNOWN);
767 spin_unlock(&tmpres->spinlock);
768 dlm_lockres_put(tmpres);
769 tmpres = NULL;
770 goto lookup;
773 /* Wait on the resource purge to complete before continuing */
774 if (tmpres->state & DLM_LOCK_RES_DROPPING_REF) {
775 BUG_ON(tmpres->owner == dlm->node_num);
776 __dlm_wait_on_lockres_flags(tmpres,
777 DLM_LOCK_RES_DROPPING_REF);
778 spin_unlock(&tmpres->spinlock);
779 dlm_lockres_put(tmpres);
780 tmpres = NULL;
781 goto lookup;
784 /* Grab inflight ref to pin the resource */
785 dlm_lockres_grab_inflight_ref(dlm, tmpres);
787 spin_unlock(&tmpres->spinlock);
788 if (res) {
789 spin_lock(&dlm->track_lock);
790 if (!list_empty(&res->tracking))
791 list_del_init(&res->tracking);
792 else
793 mlog(ML_ERROR, "Resource %.*s not "
794 "on the Tracking list\n",
795 res->lockname.len,
796 res->lockname.name);
797 spin_unlock(&dlm->track_lock);
798 dlm_lockres_put(res);
800 res = tmpres;
801 goto leave;
804 if (!res) {
805 spin_unlock(&dlm->spinlock);
806 mlog(0, "allocating a new resource\n");
807 /* nothing found and we need to allocate one. */
808 alloc_mle = kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
809 if (!alloc_mle)
810 goto leave;
811 res = dlm_new_lockres(dlm, lockid, namelen);
812 if (!res)
813 goto leave;
814 goto lookup;
817 mlog(0, "no lockres found, allocated our own: %p\n", res);
819 if (flags & LKM_LOCAL) {
820 /* caller knows it's safe to assume it's not mastered elsewhere
821 * DONE! return right away */
822 spin_lock(&res->spinlock);
823 dlm_change_lockres_owner(dlm, res, dlm->node_num);
824 __dlm_insert_lockres(dlm, res);
825 dlm_lockres_grab_inflight_ref(dlm, res);
826 spin_unlock(&res->spinlock);
827 spin_unlock(&dlm->spinlock);
828 /* lockres still marked IN_PROGRESS */
829 goto wake_waiters;
832 /* check master list to see if another node has started mastering it */
833 spin_lock(&dlm->master_lock);
835 /* if we found a block, wait for lock to be mastered by another node */
836 blocked = dlm_find_mle(dlm, &mle, (char *)lockid, namelen);
837 if (blocked) {
838 int mig;
839 if (mle->type == DLM_MLE_MASTER) {
840 mlog(ML_ERROR, "master entry for nonexistent lock!\n");
841 BUG();
843 mig = (mle->type == DLM_MLE_MIGRATION);
844 /* if there is a migration in progress, let the migration
845 * finish before continuing. we can wait for the absence
846 * of the MIGRATION mle: either the migrate finished or
847 * one of the nodes died and the mle was cleaned up.
848 * if there is a BLOCK here, but it already has a master
849 * set, we are too late. the master does not have a ref
850 * for us in the refmap. detach the mle and drop it.
851 * either way, go back to the top and start over. */
852 if (mig || mle->master != O2NM_MAX_NODES) {
853 BUG_ON(mig && mle->master == dlm->node_num);
854 /* we arrived too late. the master does not
855 * have a ref for us. retry. */
856 mlog(0, "%s:%.*s: late on %s\n",
857 dlm->name, namelen, lockid,
858 mig ? "MIGRATION" : "BLOCK");
859 spin_unlock(&dlm->master_lock);
860 spin_unlock(&dlm->spinlock);
862 /* master is known, detach */
863 if (!mig)
864 dlm_mle_detach_hb_events(dlm, mle);
865 dlm_put_mle(mle);
866 mle = NULL;
867 /* this is lame, but we can't wait on either
868 * the mle or lockres waitqueue here */
869 if (mig)
870 msleep(100);
871 goto lookup;
873 } else {
874 /* go ahead and try to master lock on this node */
875 mle = alloc_mle;
876 /* make sure this does not get freed below */
877 alloc_mle = NULL;
878 dlm_init_mle(mle, DLM_MLE_MASTER, dlm, res, NULL, 0);
879 set_bit(dlm->node_num, mle->maybe_map);
880 __dlm_insert_mle(dlm, mle);
882 /* still holding the dlm spinlock, check the recovery map
883 * to see if there are any nodes that still need to be
884 * considered. these will not appear in the mle nodemap
885 * but they might own this lockres. wait on them. */
886 bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
887 if (bit < O2NM_MAX_NODES) {
888 mlog(0, "%s: res %.*s, At least one node (%d) "
889 "to recover before lock mastery can begin\n",
890 dlm->name, namelen, (char *)lockid, bit);
891 wait_on_recovery = 1;
895 /* at this point there is either a DLM_MLE_BLOCK or a
896 * DLM_MLE_MASTER on the master list, so it's safe to add the
897 * lockres to the hashtable. anyone who finds the lock will
898 * still have to wait on the IN_PROGRESS. */
900 /* finally add the lockres to its hash bucket */
901 __dlm_insert_lockres(dlm, res);
903 /* since this lockres is new it doesn't not require the spinlock */
904 __dlm_lockres_grab_inflight_ref(dlm, res);
906 /* get an extra ref on the mle in case this is a BLOCK
907 * if so, the creator of the BLOCK may try to put the last
908 * ref at this time in the assert master handler, so we
909 * need an extra one to keep from a bad ptr deref. */
910 dlm_get_mle_inuse(mle);
911 spin_unlock(&dlm->master_lock);
912 spin_unlock(&dlm->spinlock);
914 redo_request:
915 while (wait_on_recovery) {
916 /* any cluster changes that occurred after dropping the
917 * dlm spinlock would be detectable be a change on the mle,
918 * so we only need to clear out the recovery map once. */
919 if (dlm_is_recovery_lock(lockid, namelen)) {
920 mlog(0, "%s: Recovery map is not empty, but must "
921 "master $RECOVERY lock now\n", dlm->name);
922 if (!dlm_pre_master_reco_lockres(dlm, res))
923 wait_on_recovery = 0;
924 else {
925 mlog(0, "%s: waiting 500ms for heartbeat state "
926 "change\n", dlm->name);
927 msleep(500);
929 continue;
932 dlm_kick_recovery_thread(dlm);
933 msleep(1000);
934 dlm_wait_for_recovery(dlm);
936 spin_lock(&dlm->spinlock);
937 bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
938 if (bit < O2NM_MAX_NODES) {
939 mlog(0, "%s: res %.*s, At least one node (%d) "
940 "to recover before lock mastery can begin\n",
941 dlm->name, namelen, (char *)lockid, bit);
942 wait_on_recovery = 1;
943 } else
944 wait_on_recovery = 0;
945 spin_unlock(&dlm->spinlock);
947 if (wait_on_recovery)
948 dlm_wait_for_node_recovery(dlm, bit, 10000);
951 /* must wait for lock to be mastered elsewhere */
952 if (blocked)
953 goto wait;
955 ret = -EINVAL;
956 dlm_node_iter_init(mle->vote_map, &iter);
957 while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
958 ret = dlm_do_master_request(res, mle, nodenum);
959 if (ret < 0)
960 mlog_errno(ret);
961 if (mle->master != O2NM_MAX_NODES) {
962 /* found a master ! */
963 if (mle->master <= nodenum)
964 break;
965 /* if our master request has not reached the master
966 * yet, keep going until it does. this is how the
967 * master will know that asserts are needed back to
968 * the lower nodes. */
969 mlog(0, "%s: res %.*s, Requests only up to %u but "
970 "master is %u, keep going\n", dlm->name, namelen,
971 lockid, nodenum, mle->master);
975 wait:
976 /* keep going until the response map includes all nodes */
977 ret = dlm_wait_for_lock_mastery(dlm, res, mle, &blocked);
978 if (ret < 0) {
979 wait_on_recovery = 1;
980 mlog(0, "%s: res %.*s, Node map changed, redo the master "
981 "request now, blocked=%d\n", dlm->name, res->lockname.len,
982 res->lockname.name, blocked);
983 if (++tries > 20) {
984 mlog(ML_ERROR, "%s: res %.*s, Spinning on "
985 "dlm_wait_for_lock_mastery, blocked = %d\n",
986 dlm->name, res->lockname.len,
987 res->lockname.name, blocked);
988 dlm_print_one_lock_resource(res);
989 dlm_print_one_mle(mle);
990 tries = 0;
992 goto redo_request;
995 mlog(0, "%s: res %.*s, Mastered by %u\n", dlm->name, res->lockname.len,
996 res->lockname.name, res->owner);
997 /* make sure we never continue without this */
998 BUG_ON(res->owner == O2NM_MAX_NODES);
1000 /* master is known, detach if not already detached */
1001 dlm_mle_detach_hb_events(dlm, mle);
1002 dlm_put_mle(mle);
1003 /* put the extra ref */
1004 dlm_put_mle_inuse(mle);
1006 wake_waiters:
1007 spin_lock(&res->spinlock);
1008 res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
1009 spin_unlock(&res->spinlock);
1010 wake_up(&res->wq);
1012 leave:
1013 /* need to free the unused mle */
1014 if (alloc_mle)
1015 kmem_cache_free(dlm_mle_cache, alloc_mle);
1017 return res;
1021 #define DLM_MASTERY_TIMEOUT_MS 5000
1023 static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
1024 struct dlm_lock_resource *res,
1025 struct dlm_master_list_entry *mle,
1026 int *blocked)
1028 u8 m;
1029 int ret, bit;
1030 int map_changed, voting_done;
1031 int assert, sleep;
1033 recheck:
1034 ret = 0;
1035 assert = 0;
1037 /* check if another node has already become the owner */
1038 spin_lock(&res->spinlock);
1039 if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1040 mlog(0, "%s:%.*s: owner is suddenly %u\n", dlm->name,
1041 res->lockname.len, res->lockname.name, res->owner);
1042 spin_unlock(&res->spinlock);
1043 /* this will cause the master to re-assert across
1044 * the whole cluster, freeing up mles */
1045 if (res->owner != dlm->node_num) {
1046 ret = dlm_do_master_request(res, mle, res->owner);
1047 if (ret < 0) {
1048 /* give recovery a chance to run */
1049 mlog(ML_ERROR, "link to %u went down?: %d\n", res->owner, ret);
1050 msleep(500);
1051 goto recheck;
1054 ret = 0;
1055 goto leave;
1057 spin_unlock(&res->spinlock);
1059 spin_lock(&mle->spinlock);
1060 m = mle->master;
1061 map_changed = (memcmp(mle->vote_map, mle->node_map,
1062 sizeof(mle->vote_map)) != 0);
1063 voting_done = (memcmp(mle->vote_map, mle->response_map,
1064 sizeof(mle->vote_map)) == 0);
1066 /* restart if we hit any errors */
1067 if (map_changed) {
1068 int b;
1069 mlog(0, "%s: %.*s: node map changed, restarting\n",
1070 dlm->name, res->lockname.len, res->lockname.name);
1071 ret = dlm_restart_lock_mastery(dlm, res, mle, *blocked);
1072 b = (mle->type == DLM_MLE_BLOCK);
1073 if ((*blocked && !b) || (!*blocked && b)) {
1074 mlog(0, "%s:%.*s: status change: old=%d new=%d\n",
1075 dlm->name, res->lockname.len, res->lockname.name,
1076 *blocked, b);
1077 *blocked = b;
1079 spin_unlock(&mle->spinlock);
1080 if (ret < 0) {
1081 mlog_errno(ret);
1082 goto leave;
1084 mlog(0, "%s:%.*s: restart lock mastery succeeded, "
1085 "rechecking now\n", dlm->name, res->lockname.len,
1086 res->lockname.name);
1087 goto recheck;
1088 } else {
1089 if (!voting_done) {
1090 mlog(0, "map not changed and voting not done "
1091 "for %s:%.*s\n", dlm->name, res->lockname.len,
1092 res->lockname.name);
1096 if (m != O2NM_MAX_NODES) {
1097 /* another node has done an assert!
1098 * all done! */
1099 sleep = 0;
1100 } else {
1101 sleep = 1;
1102 /* have all nodes responded? */
1103 if (voting_done && !*blocked) {
1104 bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
1105 if (dlm->node_num <= bit) {
1106 /* my node number is lowest.
1107 * now tell other nodes that I am
1108 * mastering this. */
1109 mle->master = dlm->node_num;
1110 /* ref was grabbed in get_lock_resource
1111 * will be dropped in dlmlock_master */
1112 assert = 1;
1113 sleep = 0;
1115 /* if voting is done, but we have not received
1116 * an assert master yet, we must sleep */
1120 spin_unlock(&mle->spinlock);
1122 /* sleep if we haven't finished voting yet */
1123 if (sleep) {
1124 unsigned long timeo = msecs_to_jiffies(DLM_MASTERY_TIMEOUT_MS);
1125 atomic_set(&mle->woken, 0);
1126 (void)wait_event_timeout(mle->wq,
1127 (atomic_read(&mle->woken) == 1),
1128 timeo);
1129 if (res->owner == O2NM_MAX_NODES) {
1130 mlog(0, "%s:%.*s: waiting again\n", dlm->name,
1131 res->lockname.len, res->lockname.name);
1132 goto recheck;
1134 mlog(0, "done waiting, master is %u\n", res->owner);
1135 ret = 0;
1136 goto leave;
1139 ret = 0; /* done */
1140 if (assert) {
1141 m = dlm->node_num;
1142 mlog(0, "about to master %.*s here, this=%u\n",
1143 res->lockname.len, res->lockname.name, m);
1144 ret = dlm_do_assert_master(dlm, res, mle->vote_map, 0);
1145 if (ret) {
1146 /* This is a failure in the network path,
1147 * not in the response to the assert_master
1148 * (any nonzero response is a BUG on this node).
1149 * Most likely a socket just got disconnected
1150 * due to node death. */
1151 mlog_errno(ret);
1153 /* no longer need to restart lock mastery.
1154 * all living nodes have been contacted. */
1155 ret = 0;
1158 /* set the lockres owner */
1159 spin_lock(&res->spinlock);
1160 /* mastery reference obtained either during
1161 * assert_master_handler or in get_lock_resource */
1162 dlm_change_lockres_owner(dlm, res, m);
1163 spin_unlock(&res->spinlock);
1165 leave:
1166 return ret;
1169 struct dlm_bitmap_diff_iter
1171 int curnode;
1172 unsigned long *orig_bm;
1173 unsigned long *cur_bm;
1174 unsigned long diff_bm[BITS_TO_LONGS(O2NM_MAX_NODES)];
1177 enum dlm_node_state_change
1179 NODE_DOWN = -1,
1180 NODE_NO_CHANGE = 0,
1181 NODE_UP
1184 static void dlm_bitmap_diff_iter_init(struct dlm_bitmap_diff_iter *iter,
1185 unsigned long *orig_bm,
1186 unsigned long *cur_bm)
1188 unsigned long p1, p2;
1189 int i;
1191 iter->curnode = -1;
1192 iter->orig_bm = orig_bm;
1193 iter->cur_bm = cur_bm;
1195 for (i = 0; i < BITS_TO_LONGS(O2NM_MAX_NODES); i++) {
1196 p1 = *(iter->orig_bm + i);
1197 p2 = *(iter->cur_bm + i);
1198 iter->diff_bm[i] = (p1 & ~p2) | (p2 & ~p1);
1202 static int dlm_bitmap_diff_iter_next(struct dlm_bitmap_diff_iter *iter,
1203 enum dlm_node_state_change *state)
1205 int bit;
1207 if (iter->curnode >= O2NM_MAX_NODES)
1208 return -ENOENT;
1210 bit = find_next_bit(iter->diff_bm, O2NM_MAX_NODES,
1211 iter->curnode+1);
1212 if (bit >= O2NM_MAX_NODES) {
1213 iter->curnode = O2NM_MAX_NODES;
1214 return -ENOENT;
1217 /* if it was there in the original then this node died */
1218 if (test_bit(bit, iter->orig_bm))
1219 *state = NODE_DOWN;
1220 else
1221 *state = NODE_UP;
1223 iter->curnode = bit;
1224 return bit;
1228 static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
1229 struct dlm_lock_resource *res,
1230 struct dlm_master_list_entry *mle,
1231 int blocked)
1233 struct dlm_bitmap_diff_iter bdi;
1234 enum dlm_node_state_change sc;
1235 int node;
1236 int ret = 0;
1238 mlog(0, "something happened such that the "
1239 "master process may need to be restarted!\n");
1241 assert_spin_locked(&mle->spinlock);
1243 dlm_bitmap_diff_iter_init(&bdi, mle->vote_map, mle->node_map);
1244 node = dlm_bitmap_diff_iter_next(&bdi, &sc);
1245 while (node >= 0) {
1246 if (sc == NODE_UP) {
1247 /* a node came up. clear any old vote from
1248 * the response map and set it in the vote map
1249 * then restart the mastery. */
1250 mlog(ML_NOTICE, "node %d up while restarting\n", node);
1252 /* redo the master request, but only for the new node */
1253 mlog(0, "sending request to new node\n");
1254 clear_bit(node, mle->response_map);
1255 set_bit(node, mle->vote_map);
1256 } else {
1257 mlog(ML_ERROR, "node down! %d\n", node);
1258 if (blocked) {
1259 int lowest = find_next_bit(mle->maybe_map,
1260 O2NM_MAX_NODES, 0);
1262 /* act like it was never there */
1263 clear_bit(node, mle->maybe_map);
1265 if (node == lowest) {
1266 mlog(0, "expected master %u died"
1267 " while this node was blocked "
1268 "waiting on it!\n", node);
1269 lowest = find_next_bit(mle->maybe_map,
1270 O2NM_MAX_NODES,
1271 lowest+1);
1272 if (lowest < O2NM_MAX_NODES) {
1273 mlog(0, "%s:%.*s:still "
1274 "blocked. waiting on %u "
1275 "now\n", dlm->name,
1276 res->lockname.len,
1277 res->lockname.name,
1278 lowest);
1279 } else {
1280 /* mle is an MLE_BLOCK, but
1281 * there is now nothing left to
1282 * block on. we need to return
1283 * all the way back out and try
1284 * again with an MLE_MASTER.
1285 * dlm_do_local_recovery_cleanup
1286 * has already run, so the mle
1287 * refcount is ok */
1288 mlog(0, "%s:%.*s: no "
1289 "longer blocking. try to "
1290 "master this here\n",
1291 dlm->name,
1292 res->lockname.len,
1293 res->lockname.name);
1294 mle->type = DLM_MLE_MASTER;
1295 mle->mleres = res;
1300 /* now blank out everything, as if we had never
1301 * contacted anyone */
1302 memset(mle->maybe_map, 0, sizeof(mle->maybe_map));
1303 memset(mle->response_map, 0, sizeof(mle->response_map));
1304 /* reset the vote_map to the current node_map */
1305 memcpy(mle->vote_map, mle->node_map,
1306 sizeof(mle->node_map));
1307 /* put myself into the maybe map */
1308 if (mle->type != DLM_MLE_BLOCK)
1309 set_bit(dlm->node_num, mle->maybe_map);
1311 ret = -EAGAIN;
1312 node = dlm_bitmap_diff_iter_next(&bdi, &sc);
1314 return ret;
1319 * DLM_MASTER_REQUEST_MSG
1321 * returns: 0 on success,
1322 * -errno on a network error
1324 * on error, the caller should assume the target node is "dead"
1328 static int dlm_do_master_request(struct dlm_lock_resource *res,
1329 struct dlm_master_list_entry *mle, int to)
1331 struct dlm_ctxt *dlm = mle->dlm;
1332 struct dlm_master_request request;
1333 int ret, response=0, resend;
1335 memset(&request, 0, sizeof(request));
1336 request.node_idx = dlm->node_num;
1338 BUG_ON(mle->type == DLM_MLE_MIGRATION);
1340 request.namelen = (u8)mle->mnamelen;
1341 memcpy(request.name, mle->mname, request.namelen);
1343 again:
1344 ret = o2net_send_message(DLM_MASTER_REQUEST_MSG, dlm->key, &request,
1345 sizeof(request), to, &response);
1346 if (ret < 0) {
1347 if (ret == -ESRCH) {
1348 /* should never happen */
1349 mlog(ML_ERROR, "TCP stack not ready!\n");
1350 BUG();
1351 } else if (ret == -EINVAL) {
1352 mlog(ML_ERROR, "bad args passed to o2net!\n");
1353 BUG();
1354 } else if (ret == -ENOMEM) {
1355 mlog(ML_ERROR, "out of memory while trying to send "
1356 "network message! retrying\n");
1357 /* this is totally crude */
1358 msleep(50);
1359 goto again;
1360 } else if (!dlm_is_host_down(ret)) {
1361 /* not a network error. bad. */
1362 mlog_errno(ret);
1363 mlog(ML_ERROR, "unhandled error!");
1364 BUG();
1366 /* all other errors should be network errors,
1367 * and likely indicate node death */
1368 mlog(ML_ERROR, "link to %d went down!\n", to);
1369 goto out;
1372 ret = 0;
1373 resend = 0;
1374 spin_lock(&mle->spinlock);
1375 switch (response) {
1376 case DLM_MASTER_RESP_YES:
1377 set_bit(to, mle->response_map);
1378 mlog(0, "node %u is the master, response=YES\n", to);
1379 mlog(0, "%s:%.*s: master node %u now knows I have a "
1380 "reference\n", dlm->name, res->lockname.len,
1381 res->lockname.name, to);
1382 mle->master = to;
1383 break;
1384 case DLM_MASTER_RESP_NO:
1385 mlog(0, "node %u not master, response=NO\n", to);
1386 set_bit(to, mle->response_map);
1387 break;
1388 case DLM_MASTER_RESP_MAYBE:
1389 mlog(0, "node %u not master, response=MAYBE\n", to);
1390 set_bit(to, mle->response_map);
1391 set_bit(to, mle->maybe_map);
1392 break;
1393 case DLM_MASTER_RESP_ERROR:
1394 mlog(0, "node %u hit an error, resending\n", to);
1395 resend = 1;
1396 response = 0;
1397 break;
1398 default:
1399 mlog(ML_ERROR, "bad response! %u\n", response);
1400 BUG();
1402 spin_unlock(&mle->spinlock);
1403 if (resend) {
1404 /* this is also totally crude */
1405 msleep(50);
1406 goto again;
1409 out:
1410 return ret;
1414 * locks that can be taken here:
1415 * dlm->spinlock
1416 * res->spinlock
1417 * mle->spinlock
1418 * dlm->master_list
1420 * if possible, TRIM THIS DOWN!!!
1422 int dlm_master_request_handler(struct o2net_msg *msg, u32 len, void *data,
1423 void **ret_data)
1425 u8 response = DLM_MASTER_RESP_MAYBE;
1426 struct dlm_ctxt *dlm = data;
1427 struct dlm_lock_resource *res = NULL;
1428 struct dlm_master_request *request = (struct dlm_master_request *) msg->buf;
1429 struct dlm_master_list_entry *mle = NULL, *tmpmle = NULL;
1430 char *name;
1431 unsigned int namelen, hash;
1432 int found, ret;
1433 int set_maybe;
1434 int dispatch_assert = 0;
1435 int dispatched = 0;
1437 if (!dlm_grab(dlm))
1438 return DLM_MASTER_RESP_NO;
1440 if (!dlm_domain_fully_joined(dlm)) {
1441 response = DLM_MASTER_RESP_NO;
1442 goto send_response;
1445 name = request->name;
1446 namelen = request->namelen;
1447 hash = dlm_lockid_hash(name, namelen);
1449 if (namelen > DLM_LOCKID_NAME_MAX) {
1450 response = DLM_IVBUFLEN;
1451 goto send_response;
1454 way_up_top:
1455 spin_lock(&dlm->spinlock);
1456 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
1457 if (res) {
1458 spin_unlock(&dlm->spinlock);
1460 /* take care of the easy cases up front */
1461 spin_lock(&res->spinlock);
1464 * Right after dlm spinlock was released, dlm_thread could have
1465 * purged the lockres. Check if lockres got unhashed. If so
1466 * start over.
1468 if (hlist_unhashed(&res->hash_node)) {
1469 spin_unlock(&res->spinlock);
1470 dlm_lockres_put(res);
1471 goto way_up_top;
1474 if (res->state & (DLM_LOCK_RES_RECOVERING|
1475 DLM_LOCK_RES_MIGRATING)) {
1476 spin_unlock(&res->spinlock);
1477 mlog(0, "returning DLM_MASTER_RESP_ERROR since res is "
1478 "being recovered/migrated\n");
1479 response = DLM_MASTER_RESP_ERROR;
1480 if (mle)
1481 kmem_cache_free(dlm_mle_cache, mle);
1482 goto send_response;
1485 if (res->owner == dlm->node_num) {
1486 dlm_lockres_set_refmap_bit(dlm, res, request->node_idx);
1487 spin_unlock(&res->spinlock);
1488 response = DLM_MASTER_RESP_YES;
1489 if (mle)
1490 kmem_cache_free(dlm_mle_cache, mle);
1492 /* this node is the owner.
1493 * there is some extra work that needs to
1494 * happen now. the requesting node has
1495 * caused all nodes up to this one to
1496 * create mles. this node now needs to
1497 * go back and clean those up. */
1498 dispatch_assert = 1;
1499 goto send_response;
1500 } else if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1501 spin_unlock(&res->spinlock);
1502 // mlog(0, "node %u is the master\n", res->owner);
1503 response = DLM_MASTER_RESP_NO;
1504 if (mle)
1505 kmem_cache_free(dlm_mle_cache, mle);
1506 goto send_response;
1509 /* ok, there is no owner. either this node is
1510 * being blocked, or it is actively trying to
1511 * master this lock. */
1512 if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
1513 mlog(ML_ERROR, "lock with no owner should be "
1514 "in-progress!\n");
1515 BUG();
1518 // mlog(0, "lockres is in progress...\n");
1519 spin_lock(&dlm->master_lock);
1520 found = dlm_find_mle(dlm, &tmpmle, name, namelen);
1521 if (!found) {
1522 mlog(ML_ERROR, "no mle found for this lock!\n");
1523 BUG();
1525 set_maybe = 1;
1526 spin_lock(&tmpmle->spinlock);
1527 if (tmpmle->type == DLM_MLE_BLOCK) {
1528 // mlog(0, "this node is waiting for "
1529 // "lockres to be mastered\n");
1530 response = DLM_MASTER_RESP_NO;
1531 } else if (tmpmle->type == DLM_MLE_MIGRATION) {
1532 mlog(0, "node %u is master, but trying to migrate to "
1533 "node %u.\n", tmpmle->master, tmpmle->new_master);
1534 if (tmpmle->master == dlm->node_num) {
1535 mlog(ML_ERROR, "no owner on lockres, but this "
1536 "node is trying to migrate it to %u?!\n",
1537 tmpmle->new_master);
1538 BUG();
1539 } else {
1540 /* the real master can respond on its own */
1541 response = DLM_MASTER_RESP_NO;
1543 } else if (tmpmle->master != DLM_LOCK_RES_OWNER_UNKNOWN) {
1544 set_maybe = 0;
1545 if (tmpmle->master == dlm->node_num) {
1546 response = DLM_MASTER_RESP_YES;
1547 /* this node will be the owner.
1548 * go back and clean the mles on any
1549 * other nodes */
1550 dispatch_assert = 1;
1551 dlm_lockres_set_refmap_bit(dlm, res,
1552 request->node_idx);
1553 } else
1554 response = DLM_MASTER_RESP_NO;
1555 } else {
1556 // mlog(0, "this node is attempting to "
1557 // "master lockres\n");
1558 response = DLM_MASTER_RESP_MAYBE;
1560 if (set_maybe)
1561 set_bit(request->node_idx, tmpmle->maybe_map);
1562 spin_unlock(&tmpmle->spinlock);
1564 spin_unlock(&dlm->master_lock);
1565 spin_unlock(&res->spinlock);
1567 /* keep the mle attached to heartbeat events */
1568 dlm_put_mle(tmpmle);
1569 if (mle)
1570 kmem_cache_free(dlm_mle_cache, mle);
1571 goto send_response;
1575 * lockres doesn't exist on this node
1576 * if there is an MLE_BLOCK, return NO
1577 * if there is an MLE_MASTER, return MAYBE
1578 * otherwise, add an MLE_BLOCK, return NO
1580 spin_lock(&dlm->master_lock);
1581 found = dlm_find_mle(dlm, &tmpmle, name, namelen);
1582 if (!found) {
1583 /* this lockid has never been seen on this node yet */
1584 // mlog(0, "no mle found\n");
1585 if (!mle) {
1586 spin_unlock(&dlm->master_lock);
1587 spin_unlock(&dlm->spinlock);
1589 mle = kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
1590 if (!mle) {
1591 response = DLM_MASTER_RESP_ERROR;
1592 mlog_errno(-ENOMEM);
1593 goto send_response;
1595 goto way_up_top;
1598 // mlog(0, "this is second time thru, already allocated, "
1599 // "add the block.\n");
1600 dlm_init_mle(mle, DLM_MLE_BLOCK, dlm, NULL, name, namelen);
1601 set_bit(request->node_idx, mle->maybe_map);
1602 __dlm_insert_mle(dlm, mle);
1603 response = DLM_MASTER_RESP_NO;
1604 } else {
1605 spin_lock(&tmpmle->spinlock);
1606 if (tmpmle->master == dlm->node_num) {
1607 mlog(ML_ERROR, "no lockres, but an mle with this node as master!\n");
1608 BUG();
1610 if (tmpmle->type == DLM_MLE_BLOCK)
1611 response = DLM_MASTER_RESP_NO;
1612 else if (tmpmle->type == DLM_MLE_MIGRATION) {
1613 mlog(0, "migration mle was found (%u->%u)\n",
1614 tmpmle->master, tmpmle->new_master);
1615 /* real master can respond on its own */
1616 response = DLM_MASTER_RESP_NO;
1617 } else
1618 response = DLM_MASTER_RESP_MAYBE;
1619 set_bit(request->node_idx, tmpmle->maybe_map);
1620 spin_unlock(&tmpmle->spinlock);
1622 spin_unlock(&dlm->master_lock);
1623 spin_unlock(&dlm->spinlock);
1625 if (found) {
1626 /* keep the mle attached to heartbeat events */
1627 dlm_put_mle(tmpmle);
1629 send_response:
1631 * __dlm_lookup_lockres() grabbed a reference to this lockres.
1632 * The reference is released by dlm_assert_master_worker() under
1633 * the call to dlm_dispatch_assert_master(). If
1634 * dlm_assert_master_worker() isn't called, we drop it here.
1636 if (dispatch_assert) {
1637 mlog(0, "%u is the owner of %.*s, cleaning everyone else\n",
1638 dlm->node_num, res->lockname.len, res->lockname.name);
1639 spin_lock(&res->spinlock);
1640 ret = dlm_dispatch_assert_master(dlm, res, 0, request->node_idx,
1641 DLM_ASSERT_MASTER_MLE_CLEANUP);
1642 if (ret < 0) {
1643 mlog(ML_ERROR, "failed to dispatch assert master work\n");
1644 response = DLM_MASTER_RESP_ERROR;
1645 spin_unlock(&res->spinlock);
1646 dlm_lockres_put(res);
1647 } else {
1648 dispatched = 1;
1649 __dlm_lockres_grab_inflight_worker(dlm, res);
1650 spin_unlock(&res->spinlock);
1652 } else {
1653 if (res)
1654 dlm_lockres_put(res);
1657 if (!dispatched)
1658 dlm_put(dlm);
1659 return response;
1663 * DLM_ASSERT_MASTER_MSG
1668 * NOTE: this can be used for debugging
1669 * can periodically run all locks owned by this node
1670 * and re-assert across the cluster...
1672 static int dlm_do_assert_master(struct dlm_ctxt *dlm,
1673 struct dlm_lock_resource *res,
1674 void *nodemap, u32 flags)
1676 struct dlm_assert_master assert;
1677 int to, tmpret;
1678 struct dlm_node_iter iter;
1679 int ret = 0;
1680 int reassert;
1681 const char *lockname = res->lockname.name;
1682 unsigned int namelen = res->lockname.len;
1684 BUG_ON(namelen > O2NM_MAX_NAME_LEN);
1686 spin_lock(&res->spinlock);
1687 res->state |= DLM_LOCK_RES_SETREF_INPROG;
1688 spin_unlock(&res->spinlock);
1690 again:
1691 reassert = 0;
1693 /* note that if this nodemap is empty, it returns 0 */
1694 dlm_node_iter_init(nodemap, &iter);
1695 while ((to = dlm_node_iter_next(&iter)) >= 0) {
1696 int r = 0;
1697 struct dlm_master_list_entry *mle = NULL;
1699 mlog(0, "sending assert master to %d (%.*s)\n", to,
1700 namelen, lockname);
1701 memset(&assert, 0, sizeof(assert));
1702 assert.node_idx = dlm->node_num;
1703 assert.namelen = namelen;
1704 memcpy(assert.name, lockname, namelen);
1705 assert.flags = cpu_to_be32(flags);
1707 tmpret = o2net_send_message(DLM_ASSERT_MASTER_MSG, dlm->key,
1708 &assert, sizeof(assert), to, &r);
1709 if (tmpret < 0) {
1710 mlog(ML_ERROR, "Error %d when sending message %u (key "
1711 "0x%x) to node %u\n", tmpret,
1712 DLM_ASSERT_MASTER_MSG, dlm->key, to);
1713 if (!dlm_is_host_down(tmpret)) {
1714 mlog(ML_ERROR, "unhandled error=%d!\n", tmpret);
1715 BUG();
1717 /* a node died. finish out the rest of the nodes. */
1718 mlog(0, "link to %d went down!\n", to);
1719 /* any nonzero status return will do */
1720 ret = tmpret;
1721 r = 0;
1722 } else if (r < 0) {
1723 /* ok, something horribly messed. kill thyself. */
1724 mlog(ML_ERROR,"during assert master of %.*s to %u, "
1725 "got %d.\n", namelen, lockname, to, r);
1726 spin_lock(&dlm->spinlock);
1727 spin_lock(&dlm->master_lock);
1728 if (dlm_find_mle(dlm, &mle, (char *)lockname,
1729 namelen)) {
1730 dlm_print_one_mle(mle);
1731 __dlm_put_mle(mle);
1733 spin_unlock(&dlm->master_lock);
1734 spin_unlock(&dlm->spinlock);
1735 BUG();
1738 if (r & DLM_ASSERT_RESPONSE_REASSERT &&
1739 !(r & DLM_ASSERT_RESPONSE_MASTERY_REF)) {
1740 mlog(ML_ERROR, "%.*s: very strange, "
1741 "master MLE but no lockres on %u\n",
1742 namelen, lockname, to);
1745 if (r & DLM_ASSERT_RESPONSE_REASSERT) {
1746 mlog(0, "%.*s: node %u create mles on other "
1747 "nodes and requests a re-assert\n",
1748 namelen, lockname, to);
1749 reassert = 1;
1751 if (r & DLM_ASSERT_RESPONSE_MASTERY_REF) {
1752 mlog(0, "%.*s: node %u has a reference to this "
1753 "lockres, set the bit in the refmap\n",
1754 namelen, lockname, to);
1755 spin_lock(&res->spinlock);
1756 dlm_lockres_set_refmap_bit(dlm, res, to);
1757 spin_unlock(&res->spinlock);
1761 if (reassert)
1762 goto again;
1764 spin_lock(&res->spinlock);
1765 res->state &= ~DLM_LOCK_RES_SETREF_INPROG;
1766 spin_unlock(&res->spinlock);
1767 wake_up(&res->wq);
1769 return ret;
1773 * locks that can be taken here:
1774 * dlm->spinlock
1775 * res->spinlock
1776 * mle->spinlock
1777 * dlm->master_list
1779 * if possible, TRIM THIS DOWN!!!
1781 int dlm_assert_master_handler(struct o2net_msg *msg, u32 len, void *data,
1782 void **ret_data)
1784 struct dlm_ctxt *dlm = data;
1785 struct dlm_master_list_entry *mle = NULL;
1786 struct dlm_assert_master *assert = (struct dlm_assert_master *)msg->buf;
1787 struct dlm_lock_resource *res = NULL;
1788 char *name;
1789 unsigned int namelen, hash;
1790 u32 flags;
1791 int master_request = 0, have_lockres_ref = 0;
1792 int ret = 0;
1794 if (!dlm_grab(dlm))
1795 return 0;
1797 name = assert->name;
1798 namelen = assert->namelen;
1799 hash = dlm_lockid_hash(name, namelen);
1800 flags = be32_to_cpu(assert->flags);
1802 if (namelen > DLM_LOCKID_NAME_MAX) {
1803 mlog(ML_ERROR, "Invalid name length!");
1804 goto done;
1807 spin_lock(&dlm->spinlock);
1809 if (flags)
1810 mlog(0, "assert_master with flags: %u\n", flags);
1812 /* find the MLE */
1813 spin_lock(&dlm->master_lock);
1814 if (!dlm_find_mle(dlm, &mle, name, namelen)) {
1815 /* not an error, could be master just re-asserting */
1816 mlog(0, "just got an assert_master from %u, but no "
1817 "MLE for it! (%.*s)\n", assert->node_idx,
1818 namelen, name);
1819 } else {
1820 int bit = find_next_bit (mle->maybe_map, O2NM_MAX_NODES, 0);
1821 if (bit >= O2NM_MAX_NODES) {
1822 /* not necessarily an error, though less likely.
1823 * could be master just re-asserting. */
1824 mlog(0, "no bits set in the maybe_map, but %u "
1825 "is asserting! (%.*s)\n", assert->node_idx,
1826 namelen, name);
1827 } else if (bit != assert->node_idx) {
1828 if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
1829 mlog(0, "master %u was found, %u should "
1830 "back off\n", assert->node_idx, bit);
1831 } else {
1832 /* with the fix for bug 569, a higher node
1833 * number winning the mastery will respond
1834 * YES to mastery requests, but this node
1835 * had no way of knowing. let it pass. */
1836 mlog(0, "%u is the lowest node, "
1837 "%u is asserting. (%.*s) %u must "
1838 "have begun after %u won.\n", bit,
1839 assert->node_idx, namelen, name, bit,
1840 assert->node_idx);
1843 if (mle->type == DLM_MLE_MIGRATION) {
1844 if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
1845 mlog(0, "%s:%.*s: got cleanup assert"
1846 " from %u for migration\n",
1847 dlm->name, namelen, name,
1848 assert->node_idx);
1849 } else if (!(flags & DLM_ASSERT_MASTER_FINISH_MIGRATION)) {
1850 mlog(0, "%s:%.*s: got unrelated assert"
1851 " from %u for migration, ignoring\n",
1852 dlm->name, namelen, name,
1853 assert->node_idx);
1854 __dlm_put_mle(mle);
1855 spin_unlock(&dlm->master_lock);
1856 spin_unlock(&dlm->spinlock);
1857 goto done;
1861 spin_unlock(&dlm->master_lock);
1863 /* ok everything checks out with the MLE
1864 * now check to see if there is a lockres */
1865 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
1866 if (res) {
1867 spin_lock(&res->spinlock);
1868 if (res->state & DLM_LOCK_RES_RECOVERING) {
1869 mlog(ML_ERROR, "%u asserting but %.*s is "
1870 "RECOVERING!\n", assert->node_idx, namelen, name);
1871 goto kill;
1873 if (!mle) {
1874 if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN &&
1875 res->owner != assert->node_idx) {
1876 mlog(ML_ERROR, "DIE! Mastery assert from %u, "
1877 "but current owner is %u! (%.*s)\n",
1878 assert->node_idx, res->owner, namelen,
1879 name);
1880 __dlm_print_one_lock_resource(res);
1881 BUG();
1883 } else if (mle->type != DLM_MLE_MIGRATION) {
1884 if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1885 /* owner is just re-asserting */
1886 if (res->owner == assert->node_idx) {
1887 mlog(0, "owner %u re-asserting on "
1888 "lock %.*s\n", assert->node_idx,
1889 namelen, name);
1890 goto ok;
1892 mlog(ML_ERROR, "got assert_master from "
1893 "node %u, but %u is the owner! "
1894 "(%.*s)\n", assert->node_idx,
1895 res->owner, namelen, name);
1896 goto kill;
1898 if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
1899 mlog(ML_ERROR, "got assert from %u, but lock "
1900 "with no owner should be "
1901 "in-progress! (%.*s)\n",
1902 assert->node_idx,
1903 namelen, name);
1904 goto kill;
1906 } else /* mle->type == DLM_MLE_MIGRATION */ {
1907 /* should only be getting an assert from new master */
1908 if (assert->node_idx != mle->new_master) {
1909 mlog(ML_ERROR, "got assert from %u, but "
1910 "new master is %u, and old master "
1911 "was %u (%.*s)\n",
1912 assert->node_idx, mle->new_master,
1913 mle->master, namelen, name);
1914 goto kill;
1919 spin_unlock(&res->spinlock);
1922 // mlog(0, "woo! got an assert_master from node %u!\n",
1923 // assert->node_idx);
1924 if (mle) {
1925 int extra_ref = 0;
1926 int nn = -1;
1927 int rr, err = 0;
1929 spin_lock(&mle->spinlock);
1930 if (mle->type == DLM_MLE_BLOCK || mle->type == DLM_MLE_MIGRATION)
1931 extra_ref = 1;
1932 else {
1933 /* MASTER mle: if any bits set in the response map
1934 * then the calling node needs to re-assert to clear
1935 * up nodes that this node contacted */
1936 while ((nn = find_next_bit (mle->response_map, O2NM_MAX_NODES,
1937 nn+1)) < O2NM_MAX_NODES) {
1938 if (nn != dlm->node_num && nn != assert->node_idx) {
1939 master_request = 1;
1940 break;
1944 mle->master = assert->node_idx;
1945 atomic_set(&mle->woken, 1);
1946 wake_up(&mle->wq);
1947 spin_unlock(&mle->spinlock);
1949 if (res) {
1950 int wake = 0;
1951 spin_lock(&res->spinlock);
1952 if (mle->type == DLM_MLE_MIGRATION) {
1953 mlog(0, "finishing off migration of lockres %.*s, "
1954 "from %u to %u\n",
1955 res->lockname.len, res->lockname.name,
1956 dlm->node_num, mle->new_master);
1957 res->state &= ~DLM_LOCK_RES_MIGRATING;
1958 wake = 1;
1959 dlm_change_lockres_owner(dlm, res, mle->new_master);
1960 BUG_ON(res->state & DLM_LOCK_RES_DIRTY);
1961 } else {
1962 dlm_change_lockres_owner(dlm, res, mle->master);
1964 spin_unlock(&res->spinlock);
1965 have_lockres_ref = 1;
1966 if (wake)
1967 wake_up(&res->wq);
1970 /* master is known, detach if not already detached.
1971 * ensures that only one assert_master call will happen
1972 * on this mle. */
1973 spin_lock(&dlm->master_lock);
1975 rr = kref_read(&mle->mle_refs);
1976 if (mle->inuse > 0) {
1977 if (extra_ref && rr < 3)
1978 err = 1;
1979 else if (!extra_ref && rr < 2)
1980 err = 1;
1981 } else {
1982 if (extra_ref && rr < 2)
1983 err = 1;
1984 else if (!extra_ref && rr < 1)
1985 err = 1;
1987 if (err) {
1988 mlog(ML_ERROR, "%s:%.*s: got assert master from %u "
1989 "that will mess up this node, refs=%d, extra=%d, "
1990 "inuse=%d\n", dlm->name, namelen, name,
1991 assert->node_idx, rr, extra_ref, mle->inuse);
1992 dlm_print_one_mle(mle);
1994 __dlm_unlink_mle(dlm, mle);
1995 __dlm_mle_detach_hb_events(dlm, mle);
1996 __dlm_put_mle(mle);
1997 if (extra_ref) {
1998 /* the assert master message now balances the extra
1999 * ref given by the master / migration request message.
2000 * if this is the last put, it will be removed
2001 * from the list. */
2002 __dlm_put_mle(mle);
2004 spin_unlock(&dlm->master_lock);
2005 } else if (res) {
2006 if (res->owner != assert->node_idx) {
2007 mlog(0, "assert_master from %u, but current "
2008 "owner is %u (%.*s), no mle\n", assert->node_idx,
2009 res->owner, namelen, name);
2012 spin_unlock(&dlm->spinlock);
2014 done:
2015 ret = 0;
2016 if (res) {
2017 spin_lock(&res->spinlock);
2018 res->state |= DLM_LOCK_RES_SETREF_INPROG;
2019 spin_unlock(&res->spinlock);
2020 *ret_data = (void *)res;
2022 dlm_put(dlm);
2023 if (master_request) {
2024 mlog(0, "need to tell master to reassert\n");
2025 /* positive. negative would shoot down the node. */
2026 ret |= DLM_ASSERT_RESPONSE_REASSERT;
2027 if (!have_lockres_ref) {
2028 mlog(ML_ERROR, "strange, got assert from %u, MASTER "
2029 "mle present here for %s:%.*s, but no lockres!\n",
2030 assert->node_idx, dlm->name, namelen, name);
2033 if (have_lockres_ref) {
2034 /* let the master know we have a reference to the lockres */
2035 ret |= DLM_ASSERT_RESPONSE_MASTERY_REF;
2036 mlog(0, "%s:%.*s: got assert from %u, need a ref\n",
2037 dlm->name, namelen, name, assert->node_idx);
2039 return ret;
2041 kill:
2042 /* kill the caller! */
2043 mlog(ML_ERROR, "Bad message received from another node. Dumping state "
2044 "and killing the other node now! This node is OK and can continue.\n");
2045 __dlm_print_one_lock_resource(res);
2046 spin_unlock(&res->spinlock);
2047 spin_lock(&dlm->master_lock);
2048 if (mle)
2049 __dlm_put_mle(mle);
2050 spin_unlock(&dlm->master_lock);
2051 spin_unlock(&dlm->spinlock);
2052 *ret_data = (void *)res;
2053 dlm_put(dlm);
2054 return -EINVAL;
2057 void dlm_assert_master_post_handler(int status, void *data, void *ret_data)
2059 struct dlm_lock_resource *res = (struct dlm_lock_resource *)ret_data;
2061 if (ret_data) {
2062 spin_lock(&res->spinlock);
2063 res->state &= ~DLM_LOCK_RES_SETREF_INPROG;
2064 spin_unlock(&res->spinlock);
2065 wake_up(&res->wq);
2066 dlm_lockres_put(res);
2068 return;
2071 int dlm_dispatch_assert_master(struct dlm_ctxt *dlm,
2072 struct dlm_lock_resource *res,
2073 int ignore_higher, u8 request_from, u32 flags)
2075 struct dlm_work_item *item;
2076 item = kzalloc(sizeof(*item), GFP_ATOMIC);
2077 if (!item)
2078 return -ENOMEM;
2081 /* queue up work for dlm_assert_master_worker */
2082 dlm_init_work_item(dlm, item, dlm_assert_master_worker, NULL);
2083 item->u.am.lockres = res; /* already have a ref */
2084 /* can optionally ignore node numbers higher than this node */
2085 item->u.am.ignore_higher = ignore_higher;
2086 item->u.am.request_from = request_from;
2087 item->u.am.flags = flags;
2089 if (ignore_higher)
2090 mlog(0, "IGNORE HIGHER: %.*s\n", res->lockname.len,
2091 res->lockname.name);
2093 spin_lock(&dlm->work_lock);
2094 list_add_tail(&item->list, &dlm->work_list);
2095 spin_unlock(&dlm->work_lock);
2097 queue_work(dlm->dlm_worker, &dlm->dispatched_work);
2098 return 0;
2101 static void dlm_assert_master_worker(struct dlm_work_item *item, void *data)
2103 struct dlm_ctxt *dlm = data;
2104 int ret = 0;
2105 struct dlm_lock_resource *res;
2106 unsigned long nodemap[BITS_TO_LONGS(O2NM_MAX_NODES)];
2107 int ignore_higher;
2108 int bit;
2109 u8 request_from;
2110 u32 flags;
2112 dlm = item->dlm;
2113 res = item->u.am.lockres;
2114 ignore_higher = item->u.am.ignore_higher;
2115 request_from = item->u.am.request_from;
2116 flags = item->u.am.flags;
2118 spin_lock(&dlm->spinlock);
2119 memcpy(nodemap, dlm->domain_map, sizeof(nodemap));
2120 spin_unlock(&dlm->spinlock);
2122 clear_bit(dlm->node_num, nodemap);
2123 if (ignore_higher) {
2124 /* if is this just to clear up mles for nodes below
2125 * this node, do not send the message to the original
2126 * caller or any node number higher than this */
2127 clear_bit(request_from, nodemap);
2128 bit = dlm->node_num;
2129 while (1) {
2130 bit = find_next_bit(nodemap, O2NM_MAX_NODES,
2131 bit+1);
2132 if (bit >= O2NM_MAX_NODES)
2133 break;
2134 clear_bit(bit, nodemap);
2139 * If we're migrating this lock to someone else, we are no
2140 * longer allowed to assert out own mastery. OTOH, we need to
2141 * prevent migration from starting while we're still asserting
2142 * our dominance. The reserved ast delays migration.
2144 spin_lock(&res->spinlock);
2145 if (res->state & DLM_LOCK_RES_MIGRATING) {
2146 mlog(0, "Someone asked us to assert mastery, but we're "
2147 "in the middle of migration. Skipping assert, "
2148 "the new master will handle that.\n");
2149 spin_unlock(&res->spinlock);
2150 goto put;
2151 } else
2152 __dlm_lockres_reserve_ast(res);
2153 spin_unlock(&res->spinlock);
2155 /* this call now finishes out the nodemap
2156 * even if one or more nodes die */
2157 mlog(0, "worker about to master %.*s here, this=%u\n",
2158 res->lockname.len, res->lockname.name, dlm->node_num);
2159 ret = dlm_do_assert_master(dlm, res, nodemap, flags);
2160 if (ret < 0) {
2161 /* no need to restart, we are done */
2162 if (!dlm_is_host_down(ret))
2163 mlog_errno(ret);
2166 /* Ok, we've asserted ourselves. Let's let migration start. */
2167 dlm_lockres_release_ast(dlm, res);
2169 put:
2170 dlm_lockres_drop_inflight_worker(dlm, res);
2172 dlm_lockres_put(res);
2174 mlog(0, "finished with dlm_assert_master_worker\n");
2177 /* SPECIAL CASE for the $RECOVERY lock used by the recovery thread.
2178 * We cannot wait for node recovery to complete to begin mastering this
2179 * lockres because this lockres is used to kick off recovery! ;-)
2180 * So, do a pre-check on all living nodes to see if any of those nodes
2181 * think that $RECOVERY is currently mastered by a dead node. If so,
2182 * we wait a short time to allow that node to get notified by its own
2183 * heartbeat stack, then check again. All $RECOVERY lock resources
2184 * mastered by dead nodes are purged when the hearbeat callback is
2185 * fired, so we can know for sure that it is safe to continue once
2186 * the node returns a live node or no node. */
2187 static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
2188 struct dlm_lock_resource *res)
2190 struct dlm_node_iter iter;
2191 int nodenum;
2192 int ret = 0;
2193 u8 master = DLM_LOCK_RES_OWNER_UNKNOWN;
2195 spin_lock(&dlm->spinlock);
2196 dlm_node_iter_init(dlm->domain_map, &iter);
2197 spin_unlock(&dlm->spinlock);
2199 while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
2200 /* do not send to self */
2201 if (nodenum == dlm->node_num)
2202 continue;
2203 ret = dlm_do_master_requery(dlm, res, nodenum, &master);
2204 if (ret < 0) {
2205 mlog_errno(ret);
2206 if (!dlm_is_host_down(ret))
2207 BUG();
2208 /* host is down, so answer for that node would be
2209 * DLM_LOCK_RES_OWNER_UNKNOWN. continue. */
2210 ret = 0;
2213 if (master != DLM_LOCK_RES_OWNER_UNKNOWN) {
2214 /* check to see if this master is in the recovery map */
2215 spin_lock(&dlm->spinlock);
2216 if (test_bit(master, dlm->recovery_map)) {
2217 mlog(ML_NOTICE, "%s: node %u has not seen "
2218 "node %u go down yet, and thinks the "
2219 "dead node is mastering the recovery "
2220 "lock. must wait.\n", dlm->name,
2221 nodenum, master);
2222 ret = -EAGAIN;
2224 spin_unlock(&dlm->spinlock);
2225 mlog(0, "%s: reco lock master is %u\n", dlm->name,
2226 master);
2227 break;
2230 return ret;
2234 * DLM_DEREF_LOCKRES_MSG
2237 int dlm_drop_lockres_ref(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
2239 struct dlm_deref_lockres deref;
2240 int ret = 0, r;
2241 const char *lockname;
2242 unsigned int namelen;
2244 lockname = res->lockname.name;
2245 namelen = res->lockname.len;
2246 BUG_ON(namelen > O2NM_MAX_NAME_LEN);
2248 memset(&deref, 0, sizeof(deref));
2249 deref.node_idx = dlm->node_num;
2250 deref.namelen = namelen;
2251 memcpy(deref.name, lockname, namelen);
2253 ret = o2net_send_message(DLM_DEREF_LOCKRES_MSG, dlm->key,
2254 &deref, sizeof(deref), res->owner, &r);
2255 if (ret < 0)
2256 mlog(ML_ERROR, "%s: res %.*s, error %d send DEREF to node %u\n",
2257 dlm->name, namelen, lockname, ret, res->owner);
2258 else if (r < 0) {
2259 /* BAD. other node says I did not have a ref. */
2260 mlog(ML_ERROR, "%s: res %.*s, DEREF to node %u got %d\n",
2261 dlm->name, namelen, lockname, res->owner, r);
2262 dlm_print_one_lock_resource(res);
2263 if (r == -ENOMEM)
2264 BUG();
2265 } else
2266 ret = r;
2268 return ret;
2271 int dlm_deref_lockres_handler(struct o2net_msg *msg, u32 len, void *data,
2272 void **ret_data)
2274 struct dlm_ctxt *dlm = data;
2275 struct dlm_deref_lockres *deref = (struct dlm_deref_lockres *)msg->buf;
2276 struct dlm_lock_resource *res = NULL;
2277 char *name;
2278 unsigned int namelen;
2279 int ret = -EINVAL;
2280 u8 node;
2281 unsigned int hash;
2282 struct dlm_work_item *item;
2283 int cleared = 0;
2284 int dispatch = 0;
2286 if (!dlm_grab(dlm))
2287 return 0;
2289 name = deref->name;
2290 namelen = deref->namelen;
2291 node = deref->node_idx;
2293 if (namelen > DLM_LOCKID_NAME_MAX) {
2294 mlog(ML_ERROR, "Invalid name length!");
2295 goto done;
2297 if (deref->node_idx >= O2NM_MAX_NODES) {
2298 mlog(ML_ERROR, "Invalid node number: %u\n", node);
2299 goto done;
2302 hash = dlm_lockid_hash(name, namelen);
2304 spin_lock(&dlm->spinlock);
2305 res = __dlm_lookup_lockres_full(dlm, name, namelen, hash);
2306 if (!res) {
2307 spin_unlock(&dlm->spinlock);
2308 mlog(ML_ERROR, "%s:%.*s: bad lockres name\n",
2309 dlm->name, namelen, name);
2310 goto done;
2312 spin_unlock(&dlm->spinlock);
2314 spin_lock(&res->spinlock);
2315 if (res->state & DLM_LOCK_RES_SETREF_INPROG)
2316 dispatch = 1;
2317 else {
2318 BUG_ON(res->state & DLM_LOCK_RES_DROPPING_REF);
2319 if (test_bit(node, res->refmap)) {
2320 dlm_lockres_clear_refmap_bit(dlm, res, node);
2321 cleared = 1;
2324 spin_unlock(&res->spinlock);
2326 if (!dispatch) {
2327 if (cleared)
2328 dlm_lockres_calc_usage(dlm, res);
2329 else {
2330 mlog(ML_ERROR, "%s:%.*s: node %u trying to drop ref "
2331 "but it is already dropped!\n", dlm->name,
2332 res->lockname.len, res->lockname.name, node);
2333 dlm_print_one_lock_resource(res);
2335 ret = DLM_DEREF_RESPONSE_DONE;
2336 goto done;
2339 item = kzalloc(sizeof(*item), GFP_NOFS);
2340 if (!item) {
2341 ret = -ENOMEM;
2342 mlog_errno(ret);
2343 goto done;
2346 dlm_init_work_item(dlm, item, dlm_deref_lockres_worker, NULL);
2347 item->u.dl.deref_res = res;
2348 item->u.dl.deref_node = node;
2350 spin_lock(&dlm->work_lock);
2351 list_add_tail(&item->list, &dlm->work_list);
2352 spin_unlock(&dlm->work_lock);
2354 queue_work(dlm->dlm_worker, &dlm->dispatched_work);
2355 return DLM_DEREF_RESPONSE_INPROG;
2357 done:
2358 if (res)
2359 dlm_lockres_put(res);
2360 dlm_put(dlm);
2362 return ret;
2365 int dlm_deref_lockres_done_handler(struct o2net_msg *msg, u32 len, void *data,
2366 void **ret_data)
2368 struct dlm_ctxt *dlm = data;
2369 struct dlm_deref_lockres_done *deref
2370 = (struct dlm_deref_lockres_done *)msg->buf;
2371 struct dlm_lock_resource *res = NULL;
2372 char *name;
2373 unsigned int namelen;
2374 int ret = -EINVAL;
2375 u8 node;
2376 unsigned int hash;
2378 if (!dlm_grab(dlm))
2379 return 0;
2381 name = deref->name;
2382 namelen = deref->namelen;
2383 node = deref->node_idx;
2385 if (namelen > DLM_LOCKID_NAME_MAX) {
2386 mlog(ML_ERROR, "Invalid name length!");
2387 goto done;
2389 if (deref->node_idx >= O2NM_MAX_NODES) {
2390 mlog(ML_ERROR, "Invalid node number: %u\n", node);
2391 goto done;
2394 hash = dlm_lockid_hash(name, namelen);
2396 spin_lock(&dlm->spinlock);
2397 res = __dlm_lookup_lockres_full(dlm, name, namelen, hash);
2398 if (!res) {
2399 spin_unlock(&dlm->spinlock);
2400 mlog(ML_ERROR, "%s:%.*s: bad lockres name\n",
2401 dlm->name, namelen, name);
2402 goto done;
2405 spin_lock(&res->spinlock);
2406 if (!(res->state & DLM_LOCK_RES_DROPPING_REF)) {
2407 spin_unlock(&res->spinlock);
2408 spin_unlock(&dlm->spinlock);
2409 mlog(ML_NOTICE, "%s:%.*s: node %u sends deref done "
2410 "but it is already derefed!\n", dlm->name,
2411 res->lockname.len, res->lockname.name, node);
2412 ret = 0;
2413 goto done;
2416 __dlm_do_purge_lockres(dlm, res);
2417 spin_unlock(&res->spinlock);
2418 wake_up(&res->wq);
2420 spin_unlock(&dlm->spinlock);
2422 ret = 0;
2423 done:
2424 if (res)
2425 dlm_lockres_put(res);
2426 dlm_put(dlm);
2427 return ret;
2430 static void dlm_drop_lockres_ref_done(struct dlm_ctxt *dlm,
2431 struct dlm_lock_resource *res, u8 node)
2433 struct dlm_deref_lockres_done deref;
2434 int ret = 0, r;
2435 const char *lockname;
2436 unsigned int namelen;
2438 lockname = res->lockname.name;
2439 namelen = res->lockname.len;
2440 BUG_ON(namelen > O2NM_MAX_NAME_LEN);
2442 memset(&deref, 0, sizeof(deref));
2443 deref.node_idx = dlm->node_num;
2444 deref.namelen = namelen;
2445 memcpy(deref.name, lockname, namelen);
2447 ret = o2net_send_message(DLM_DEREF_LOCKRES_DONE, dlm->key,
2448 &deref, sizeof(deref), node, &r);
2449 if (ret < 0) {
2450 mlog(ML_ERROR, "%s: res %.*s, error %d send DEREF DONE "
2451 " to node %u\n", dlm->name, namelen,
2452 lockname, ret, node);
2453 } else if (r < 0) {
2454 /* ignore the error */
2455 mlog(ML_ERROR, "%s: res %.*s, DEREF to node %u got %d\n",
2456 dlm->name, namelen, lockname, node, r);
2457 dlm_print_one_lock_resource(res);
2461 static void dlm_deref_lockres_worker(struct dlm_work_item *item, void *data)
2463 struct dlm_ctxt *dlm;
2464 struct dlm_lock_resource *res;
2465 u8 node;
2466 u8 cleared = 0;
2468 dlm = item->dlm;
2469 res = item->u.dl.deref_res;
2470 node = item->u.dl.deref_node;
2472 spin_lock(&res->spinlock);
2473 BUG_ON(res->state & DLM_LOCK_RES_DROPPING_REF);
2474 __dlm_wait_on_lockres_flags(res, DLM_LOCK_RES_SETREF_INPROG);
2475 if (test_bit(node, res->refmap)) {
2476 dlm_lockres_clear_refmap_bit(dlm, res, node);
2477 cleared = 1;
2479 spin_unlock(&res->spinlock);
2481 dlm_drop_lockres_ref_done(dlm, res, node);
2483 if (cleared) {
2484 mlog(0, "%s:%.*s node %u ref dropped in dispatch\n",
2485 dlm->name, res->lockname.len, res->lockname.name, node);
2486 dlm_lockres_calc_usage(dlm, res);
2487 } else {
2488 mlog(ML_ERROR, "%s:%.*s: node %u trying to drop ref "
2489 "but it is already dropped!\n", dlm->name,
2490 res->lockname.len, res->lockname.name, node);
2491 dlm_print_one_lock_resource(res);
2494 dlm_lockres_put(res);
2498 * A migrateable resource is one that is :
2499 * 1. locally mastered, and,
2500 * 2. zero local locks, and,
2501 * 3. one or more non-local locks, or, one or more references
2502 * Returns 1 if yes, 0 if not.
2504 static int dlm_is_lockres_migrateable(struct dlm_ctxt *dlm,
2505 struct dlm_lock_resource *res)
2507 enum dlm_lockres_list idx;
2508 int nonlocal = 0, node_ref;
2509 struct list_head *queue;
2510 struct dlm_lock *lock;
2511 u64 cookie;
2513 assert_spin_locked(&res->spinlock);
2515 /* delay migration when the lockres is in MIGRATING state */
2516 if (res->state & DLM_LOCK_RES_MIGRATING)
2517 return 0;
2519 /* delay migration when the lockres is in RECOCERING state */
2520 if (res->state & (DLM_LOCK_RES_RECOVERING|
2521 DLM_LOCK_RES_RECOVERY_WAITING))
2522 return 0;
2524 if (res->owner != dlm->node_num)
2525 return 0;
2527 for (idx = DLM_GRANTED_LIST; idx <= DLM_BLOCKED_LIST; idx++) {
2528 queue = dlm_list_idx_to_ptr(res, idx);
2529 list_for_each_entry(lock, queue, list) {
2530 if (lock->ml.node != dlm->node_num) {
2531 nonlocal++;
2532 continue;
2534 cookie = be64_to_cpu(lock->ml.cookie);
2535 mlog(0, "%s: Not migrateable res %.*s, lock %u:%llu on "
2536 "%s list\n", dlm->name, res->lockname.len,
2537 res->lockname.name,
2538 dlm_get_lock_cookie_node(cookie),
2539 dlm_get_lock_cookie_seq(cookie),
2540 dlm_list_in_text(idx));
2541 return 0;
2545 if (!nonlocal) {
2546 node_ref = find_next_bit(res->refmap, O2NM_MAX_NODES, 0);
2547 if (node_ref >= O2NM_MAX_NODES)
2548 return 0;
2551 mlog(0, "%s: res %.*s, Migrateable\n", dlm->name, res->lockname.len,
2552 res->lockname.name);
2554 return 1;
2558 * DLM_MIGRATE_LOCKRES
2562 static int dlm_migrate_lockres(struct dlm_ctxt *dlm,
2563 struct dlm_lock_resource *res, u8 target)
2565 struct dlm_master_list_entry *mle = NULL;
2566 struct dlm_master_list_entry *oldmle = NULL;
2567 struct dlm_migratable_lockres *mres = NULL;
2568 int ret = 0;
2569 const char *name;
2570 unsigned int namelen;
2571 int mle_added = 0;
2572 int wake = 0;
2574 if (!dlm_grab(dlm))
2575 return -EINVAL;
2577 BUG_ON(target == O2NM_MAX_NODES);
2579 name = res->lockname.name;
2580 namelen = res->lockname.len;
2582 mlog(0, "%s: Migrating %.*s to node %u\n", dlm->name, namelen, name,
2583 target);
2585 /* preallocate up front. if this fails, abort */
2586 ret = -ENOMEM;
2587 mres = (struct dlm_migratable_lockres *) __get_free_page(GFP_NOFS);
2588 if (!mres) {
2589 mlog_errno(ret);
2590 goto leave;
2593 mle = kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
2594 if (!mle) {
2595 mlog_errno(ret);
2596 goto leave;
2598 ret = 0;
2601 * clear any existing master requests and
2602 * add the migration mle to the list
2604 spin_lock(&dlm->spinlock);
2605 spin_lock(&dlm->master_lock);
2606 ret = dlm_add_migration_mle(dlm, res, mle, &oldmle, name,
2607 namelen, target, dlm->node_num);
2608 /* get an extra reference on the mle.
2609 * otherwise the assert_master from the new
2610 * master will destroy this.
2612 if (ret != -EEXIST)
2613 dlm_get_mle_inuse(mle);
2615 spin_unlock(&dlm->master_lock);
2616 spin_unlock(&dlm->spinlock);
2618 if (ret == -EEXIST) {
2619 mlog(0, "another process is already migrating it\n");
2620 goto fail;
2622 mle_added = 1;
2625 * set the MIGRATING flag and flush asts
2626 * if we fail after this we need to re-dirty the lockres
2628 if (dlm_mark_lockres_migrating(dlm, res, target) < 0) {
2629 mlog(ML_ERROR, "tried to migrate %.*s to %u, but "
2630 "the target went down.\n", res->lockname.len,
2631 res->lockname.name, target);
2632 spin_lock(&res->spinlock);
2633 res->state &= ~DLM_LOCK_RES_MIGRATING;
2634 wake = 1;
2635 spin_unlock(&res->spinlock);
2636 ret = -EINVAL;
2639 fail:
2640 if (ret != -EEXIST && oldmle) {
2641 /* master is known, detach if not already detached */
2642 dlm_mle_detach_hb_events(dlm, oldmle);
2643 dlm_put_mle(oldmle);
2646 if (ret < 0) {
2647 if (mle_added) {
2648 dlm_mle_detach_hb_events(dlm, mle);
2649 dlm_put_mle(mle);
2650 dlm_put_mle_inuse(mle);
2651 } else if (mle) {
2652 kmem_cache_free(dlm_mle_cache, mle);
2653 mle = NULL;
2655 goto leave;
2659 * at this point, we have a migration target, an mle
2660 * in the master list, and the MIGRATING flag set on
2661 * the lockres
2664 /* now that remote nodes are spinning on the MIGRATING flag,
2665 * ensure that all assert_master work is flushed. */
2666 flush_workqueue(dlm->dlm_worker);
2668 /* notify new node and send all lock state */
2669 /* call send_one_lockres with migration flag.
2670 * this serves as notice to the target node that a
2671 * migration is starting. */
2672 ret = dlm_send_one_lockres(dlm, res, mres, target,
2673 DLM_MRES_MIGRATION);
2675 if (ret < 0) {
2676 mlog(0, "migration to node %u failed with %d\n",
2677 target, ret);
2678 /* migration failed, detach and clean up mle */
2679 dlm_mle_detach_hb_events(dlm, mle);
2680 dlm_put_mle(mle);
2681 dlm_put_mle_inuse(mle);
2682 spin_lock(&res->spinlock);
2683 res->state &= ~DLM_LOCK_RES_MIGRATING;
2684 wake = 1;
2685 spin_unlock(&res->spinlock);
2686 if (dlm_is_host_down(ret))
2687 dlm_wait_for_node_death(dlm, target,
2688 DLM_NODE_DEATH_WAIT_MAX);
2689 goto leave;
2692 /* at this point, the target sends a message to all nodes,
2693 * (using dlm_do_migrate_request). this node is skipped since
2694 * we had to put an mle in the list to begin the process. this
2695 * node now waits for target to do an assert master. this node
2696 * will be the last one notified, ensuring that the migration
2697 * is complete everywhere. if the target dies while this is
2698 * going on, some nodes could potentially see the target as the
2699 * master, so it is important that my recovery finds the migration
2700 * mle and sets the master to UNKNOWN. */
2703 /* wait for new node to assert master */
2704 while (1) {
2705 ret = wait_event_interruptible_timeout(mle->wq,
2706 (atomic_read(&mle->woken) == 1),
2707 msecs_to_jiffies(5000));
2709 if (ret >= 0) {
2710 if (atomic_read(&mle->woken) == 1 ||
2711 res->owner == target)
2712 break;
2714 mlog(0, "%s:%.*s: timed out during migration\n",
2715 dlm->name, res->lockname.len, res->lockname.name);
2716 /* avoid hang during shutdown when migrating lockres
2717 * to a node which also goes down */
2718 if (dlm_is_node_dead(dlm, target)) {
2719 mlog(0, "%s:%.*s: expected migration "
2720 "target %u is no longer up, restarting\n",
2721 dlm->name, res->lockname.len,
2722 res->lockname.name, target);
2723 ret = -EINVAL;
2724 /* migration failed, detach and clean up mle */
2725 dlm_mle_detach_hb_events(dlm, mle);
2726 dlm_put_mle(mle);
2727 dlm_put_mle_inuse(mle);
2728 spin_lock(&res->spinlock);
2729 res->state &= ~DLM_LOCK_RES_MIGRATING;
2730 wake = 1;
2731 spin_unlock(&res->spinlock);
2732 goto leave;
2734 } else
2735 mlog(0, "%s:%.*s: caught signal during migration\n",
2736 dlm->name, res->lockname.len, res->lockname.name);
2739 /* all done, set the owner, clear the flag */
2740 spin_lock(&res->spinlock);
2741 dlm_set_lockres_owner(dlm, res, target);
2742 res->state &= ~DLM_LOCK_RES_MIGRATING;
2743 dlm_remove_nonlocal_locks(dlm, res);
2744 spin_unlock(&res->spinlock);
2745 wake_up(&res->wq);
2747 /* master is known, detach if not already detached */
2748 dlm_mle_detach_hb_events(dlm, mle);
2749 dlm_put_mle_inuse(mle);
2750 ret = 0;
2752 dlm_lockres_calc_usage(dlm, res);
2754 leave:
2755 /* re-dirty the lockres if we failed */
2756 if (ret < 0)
2757 dlm_kick_thread(dlm, res);
2759 /* wake up waiters if the MIGRATING flag got set
2760 * but migration failed */
2761 if (wake)
2762 wake_up(&res->wq);
2764 if (mres)
2765 free_page((unsigned long)mres);
2767 dlm_put(dlm);
2769 mlog(0, "%s: Migrating %.*s to %u, returns %d\n", dlm->name, namelen,
2770 name, target, ret);
2771 return ret;
2774 #define DLM_MIGRATION_RETRY_MS 100
2777 * Should be called only after beginning the domain leave process.
2778 * There should not be any remaining locks on nonlocal lock resources,
2779 * and there should be no local locks left on locally mastered resources.
2781 * Called with the dlm spinlock held, may drop it to do migration, but
2782 * will re-acquire before exit.
2784 * Returns: 1 if dlm->spinlock was dropped/retaken, 0 if never dropped
2786 int dlm_empty_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
2788 int ret;
2789 int lock_dropped = 0;
2790 u8 target = O2NM_MAX_NODES;
2792 assert_spin_locked(&dlm->spinlock);
2794 spin_lock(&res->spinlock);
2795 if (dlm_is_lockres_migrateable(dlm, res))
2796 target = dlm_pick_migration_target(dlm, res);
2797 spin_unlock(&res->spinlock);
2799 if (target == O2NM_MAX_NODES)
2800 goto leave;
2802 /* Wheee! Migrate lockres here! Will sleep so drop spinlock. */
2803 spin_unlock(&dlm->spinlock);
2804 lock_dropped = 1;
2805 ret = dlm_migrate_lockres(dlm, res, target);
2806 if (ret)
2807 mlog(0, "%s: res %.*s, Migrate to node %u failed with %d\n",
2808 dlm->name, res->lockname.len, res->lockname.name,
2809 target, ret);
2810 spin_lock(&dlm->spinlock);
2811 leave:
2812 return lock_dropped;
2815 int dlm_lock_basts_flushed(struct dlm_ctxt *dlm, struct dlm_lock *lock)
2817 int ret;
2818 spin_lock(&dlm->ast_lock);
2819 spin_lock(&lock->spinlock);
2820 ret = (list_empty(&lock->bast_list) && !lock->bast_pending);
2821 spin_unlock(&lock->spinlock);
2822 spin_unlock(&dlm->ast_lock);
2823 return ret;
2826 static int dlm_migration_can_proceed(struct dlm_ctxt *dlm,
2827 struct dlm_lock_resource *res,
2828 u8 mig_target)
2830 int can_proceed;
2831 spin_lock(&res->spinlock);
2832 can_proceed = !!(res->state & DLM_LOCK_RES_MIGRATING);
2833 spin_unlock(&res->spinlock);
2835 /* target has died, so make the caller break out of the
2836 * wait_event, but caller must recheck the domain_map */
2837 spin_lock(&dlm->spinlock);
2838 if (!test_bit(mig_target, dlm->domain_map))
2839 can_proceed = 1;
2840 spin_unlock(&dlm->spinlock);
2841 return can_proceed;
2844 static int dlm_lockres_is_dirty(struct dlm_ctxt *dlm,
2845 struct dlm_lock_resource *res)
2847 int ret;
2848 spin_lock(&res->spinlock);
2849 ret = !!(res->state & DLM_LOCK_RES_DIRTY);
2850 spin_unlock(&res->spinlock);
2851 return ret;
2855 static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
2856 struct dlm_lock_resource *res,
2857 u8 target)
2859 int ret = 0;
2861 mlog(0, "dlm_mark_lockres_migrating: %.*s, from %u to %u\n",
2862 res->lockname.len, res->lockname.name, dlm->node_num,
2863 target);
2864 /* need to set MIGRATING flag on lockres. this is done by
2865 * ensuring that all asts have been flushed for this lockres. */
2866 spin_lock(&res->spinlock);
2867 BUG_ON(res->migration_pending);
2868 res->migration_pending = 1;
2869 /* strategy is to reserve an extra ast then release
2870 * it below, letting the release do all of the work */
2871 __dlm_lockres_reserve_ast(res);
2872 spin_unlock(&res->spinlock);
2874 /* now flush all the pending asts */
2875 dlm_kick_thread(dlm, res);
2876 /* before waiting on DIRTY, block processes which may
2877 * try to dirty the lockres before MIGRATING is set */
2878 spin_lock(&res->spinlock);
2879 BUG_ON(res->state & DLM_LOCK_RES_BLOCK_DIRTY);
2880 res->state |= DLM_LOCK_RES_BLOCK_DIRTY;
2881 spin_unlock(&res->spinlock);
2882 /* now wait on any pending asts and the DIRTY state */
2883 wait_event(dlm->ast_wq, !dlm_lockres_is_dirty(dlm, res));
2884 dlm_lockres_release_ast(dlm, res);
2886 mlog(0, "about to wait on migration_wq, dirty=%s\n",
2887 res->state & DLM_LOCK_RES_DIRTY ? "yes" : "no");
2888 /* if the extra ref we just put was the final one, this
2889 * will pass thru immediately. otherwise, we need to wait
2890 * for the last ast to finish. */
2891 again:
2892 ret = wait_event_interruptible_timeout(dlm->migration_wq,
2893 dlm_migration_can_proceed(dlm, res, target),
2894 msecs_to_jiffies(1000));
2895 if (ret < 0) {
2896 mlog(0, "woken again: migrating? %s, dead? %s\n",
2897 res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
2898 test_bit(target, dlm->domain_map) ? "no":"yes");
2899 } else {
2900 mlog(0, "all is well: migrating? %s, dead? %s\n",
2901 res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
2902 test_bit(target, dlm->domain_map) ? "no":"yes");
2904 if (!dlm_migration_can_proceed(dlm, res, target)) {
2905 mlog(0, "trying again...\n");
2906 goto again;
2909 ret = 0;
2910 /* did the target go down or die? */
2911 spin_lock(&dlm->spinlock);
2912 if (!test_bit(target, dlm->domain_map)) {
2913 mlog(ML_ERROR, "aha. migration target %u just went down\n",
2914 target);
2915 ret = -EHOSTDOWN;
2917 spin_unlock(&dlm->spinlock);
2920 * if target is down, we need to clear DLM_LOCK_RES_BLOCK_DIRTY for
2921 * another try; otherwise, we are sure the MIGRATING state is there,
2922 * drop the unneeded state which blocked threads trying to DIRTY
2924 spin_lock(&res->spinlock);
2925 BUG_ON(!(res->state & DLM_LOCK_RES_BLOCK_DIRTY));
2926 res->state &= ~DLM_LOCK_RES_BLOCK_DIRTY;
2927 if (!ret)
2928 BUG_ON(!(res->state & DLM_LOCK_RES_MIGRATING));
2929 else
2930 res->migration_pending = 0;
2931 spin_unlock(&res->spinlock);
2934 * at this point:
2936 * o the DLM_LOCK_RES_MIGRATING flag is set if target not down
2937 * o there are no pending asts on this lockres
2938 * o all processes trying to reserve an ast on this
2939 * lockres must wait for the MIGRATING flag to clear
2941 return ret;
2944 /* last step in the migration process.
2945 * original master calls this to free all of the dlm_lock
2946 * structures that used to be for other nodes. */
2947 static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
2948 struct dlm_lock_resource *res)
2950 struct list_head *queue = &res->granted;
2951 int i, bit;
2952 struct dlm_lock *lock, *next;
2954 assert_spin_locked(&res->spinlock);
2956 BUG_ON(res->owner == dlm->node_num);
2958 for (i=0; i<3; i++) {
2959 list_for_each_entry_safe(lock, next, queue, list) {
2960 if (lock->ml.node != dlm->node_num) {
2961 mlog(0, "putting lock for node %u\n",
2962 lock->ml.node);
2963 /* be extra careful */
2964 BUG_ON(!list_empty(&lock->ast_list));
2965 BUG_ON(!list_empty(&lock->bast_list));
2966 BUG_ON(lock->ast_pending);
2967 BUG_ON(lock->bast_pending);
2968 dlm_lockres_clear_refmap_bit(dlm, res,
2969 lock->ml.node);
2970 list_del_init(&lock->list);
2971 dlm_lock_put(lock);
2972 /* In a normal unlock, we would have added a
2973 * DLM_UNLOCK_FREE_LOCK action. Force it. */
2974 dlm_lock_put(lock);
2977 queue++;
2979 bit = 0;
2980 while (1) {
2981 bit = find_next_bit(res->refmap, O2NM_MAX_NODES, bit);
2982 if (bit >= O2NM_MAX_NODES)
2983 break;
2984 /* do not clear the local node reference, if there is a
2985 * process holding this, let it drop the ref itself */
2986 if (bit != dlm->node_num) {
2987 mlog(0, "%s:%.*s: node %u had a ref to this "
2988 "migrating lockres, clearing\n", dlm->name,
2989 res->lockname.len, res->lockname.name, bit);
2990 dlm_lockres_clear_refmap_bit(dlm, res, bit);
2992 bit++;
2997 * Pick a node to migrate the lock resource to. This function selects a
2998 * potential target based first on the locks and then on refmap. It skips
2999 * nodes that are in the process of exiting the domain.
3001 static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
3002 struct dlm_lock_resource *res)
3004 enum dlm_lockres_list idx;
3005 struct list_head *queue = &res->granted;
3006 struct dlm_lock *lock;
3007 int noderef;
3008 u8 nodenum = O2NM_MAX_NODES;
3010 assert_spin_locked(&dlm->spinlock);
3011 assert_spin_locked(&res->spinlock);
3013 /* Go through all the locks */
3014 for (idx = DLM_GRANTED_LIST; idx <= DLM_BLOCKED_LIST; idx++) {
3015 queue = dlm_list_idx_to_ptr(res, idx);
3016 list_for_each_entry(lock, queue, list) {
3017 if (lock->ml.node == dlm->node_num)
3018 continue;
3019 if (test_bit(lock->ml.node, dlm->exit_domain_map))
3020 continue;
3021 nodenum = lock->ml.node;
3022 goto bail;
3026 /* Go thru the refmap */
3027 noderef = -1;
3028 while (1) {
3029 noderef = find_next_bit(res->refmap, O2NM_MAX_NODES,
3030 noderef + 1);
3031 if (noderef >= O2NM_MAX_NODES)
3032 break;
3033 if (noderef == dlm->node_num)
3034 continue;
3035 if (test_bit(noderef, dlm->exit_domain_map))
3036 continue;
3037 nodenum = noderef;
3038 goto bail;
3041 bail:
3042 return nodenum;
3045 /* this is called by the new master once all lockres
3046 * data has been received */
3047 static int dlm_do_migrate_request(struct dlm_ctxt *dlm,
3048 struct dlm_lock_resource *res,
3049 u8 master, u8 new_master,
3050 struct dlm_node_iter *iter)
3052 struct dlm_migrate_request migrate;
3053 int ret, skip, status = 0;
3054 int nodenum;
3056 memset(&migrate, 0, sizeof(migrate));
3057 migrate.namelen = res->lockname.len;
3058 memcpy(migrate.name, res->lockname.name, migrate.namelen);
3059 migrate.new_master = new_master;
3060 migrate.master = master;
3062 ret = 0;
3064 /* send message to all nodes, except the master and myself */
3065 while ((nodenum = dlm_node_iter_next(iter)) >= 0) {
3066 if (nodenum == master ||
3067 nodenum == new_master)
3068 continue;
3070 /* We could race exit domain. If exited, skip. */
3071 spin_lock(&dlm->spinlock);
3072 skip = (!test_bit(nodenum, dlm->domain_map));
3073 spin_unlock(&dlm->spinlock);
3074 if (skip) {
3075 clear_bit(nodenum, iter->node_map);
3076 continue;
3079 ret = o2net_send_message(DLM_MIGRATE_REQUEST_MSG, dlm->key,
3080 &migrate, sizeof(migrate), nodenum,
3081 &status);
3082 if (ret < 0) {
3083 mlog(ML_ERROR, "%s: res %.*s, Error %d send "
3084 "MIGRATE_REQUEST to node %u\n", dlm->name,
3085 migrate.namelen, migrate.name, ret, nodenum);
3086 if (!dlm_is_host_down(ret)) {
3087 mlog(ML_ERROR, "unhandled error=%d!\n", ret);
3088 BUG();
3090 clear_bit(nodenum, iter->node_map);
3091 ret = 0;
3092 } else if (status < 0) {
3093 mlog(0, "migrate request (node %u) returned %d!\n",
3094 nodenum, status);
3095 ret = status;
3096 } else if (status == DLM_MIGRATE_RESPONSE_MASTERY_REF) {
3097 /* during the migration request we short-circuited
3098 * the mastery of the lockres. make sure we have
3099 * a mastery ref for nodenum */
3100 mlog(0, "%s:%.*s: need ref for node %u\n",
3101 dlm->name, res->lockname.len, res->lockname.name,
3102 nodenum);
3103 spin_lock(&res->spinlock);
3104 dlm_lockres_set_refmap_bit(dlm, res, nodenum);
3105 spin_unlock(&res->spinlock);
3109 if (ret < 0)
3110 mlog_errno(ret);
3112 mlog(0, "returning ret=%d\n", ret);
3113 return ret;
3117 /* if there is an existing mle for this lockres, we now know who the master is.
3118 * (the one who sent us *this* message) we can clear it up right away.
3119 * since the process that put the mle on the list still has a reference to it,
3120 * we can unhash it now, set the master and wake the process. as a result,
3121 * we will have no mle in the list to start with. now we can add an mle for
3122 * the migration and this should be the only one found for those scanning the
3123 * list. */
3124 int dlm_migrate_request_handler(struct o2net_msg *msg, u32 len, void *data,
3125 void **ret_data)
3127 struct dlm_ctxt *dlm = data;
3128 struct dlm_lock_resource *res = NULL;
3129 struct dlm_migrate_request *migrate = (struct dlm_migrate_request *) msg->buf;
3130 struct dlm_master_list_entry *mle = NULL, *oldmle = NULL;
3131 const char *name;
3132 unsigned int namelen, hash;
3133 int ret = 0;
3135 if (!dlm_grab(dlm))
3136 return 0;
3138 name = migrate->name;
3139 namelen = migrate->namelen;
3140 hash = dlm_lockid_hash(name, namelen);
3142 /* preallocate.. if this fails, abort */
3143 mle = kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
3145 if (!mle) {
3146 ret = -ENOMEM;
3147 goto leave;
3150 /* check for pre-existing lock */
3151 spin_lock(&dlm->spinlock);
3152 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
3153 if (res) {
3154 spin_lock(&res->spinlock);
3155 if (res->state & DLM_LOCK_RES_RECOVERING) {
3156 /* if all is working ok, this can only mean that we got
3157 * a migrate request from a node that we now see as
3158 * dead. what can we do here? drop it to the floor? */
3159 spin_unlock(&res->spinlock);
3160 mlog(ML_ERROR, "Got a migrate request, but the "
3161 "lockres is marked as recovering!");
3162 kmem_cache_free(dlm_mle_cache, mle);
3163 ret = -EINVAL; /* need a better solution */
3164 goto unlock;
3166 res->state |= DLM_LOCK_RES_MIGRATING;
3167 spin_unlock(&res->spinlock);
3170 spin_lock(&dlm->master_lock);
3171 /* ignore status. only nonzero status would BUG. */
3172 ret = dlm_add_migration_mle(dlm, res, mle, &oldmle,
3173 name, namelen,
3174 migrate->new_master,
3175 migrate->master);
3177 if (ret < 0)
3178 kmem_cache_free(dlm_mle_cache, mle);
3180 spin_unlock(&dlm->master_lock);
3181 unlock:
3182 spin_unlock(&dlm->spinlock);
3184 if (oldmle) {
3185 /* master is known, detach if not already detached */
3186 dlm_mle_detach_hb_events(dlm, oldmle);
3187 dlm_put_mle(oldmle);
3190 if (res)
3191 dlm_lockres_put(res);
3192 leave:
3193 dlm_put(dlm);
3194 return ret;
3197 /* must be holding dlm->spinlock and dlm->master_lock
3198 * when adding a migration mle, we can clear any other mles
3199 * in the master list because we know with certainty that
3200 * the master is "master". so we remove any old mle from
3201 * the list after setting it's master field, and then add
3202 * the new migration mle. this way we can hold with the rule
3203 * of having only one mle for a given lock name at all times. */
3204 static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
3205 struct dlm_lock_resource *res,
3206 struct dlm_master_list_entry *mle,
3207 struct dlm_master_list_entry **oldmle,
3208 const char *name, unsigned int namelen,
3209 u8 new_master, u8 master)
3211 int found;
3212 int ret = 0;
3214 *oldmle = NULL;
3216 assert_spin_locked(&dlm->spinlock);
3217 assert_spin_locked(&dlm->master_lock);
3219 /* caller is responsible for any ref taken here on oldmle */
3220 found = dlm_find_mle(dlm, oldmle, (char *)name, namelen);
3221 if (found) {
3222 struct dlm_master_list_entry *tmp = *oldmle;
3223 spin_lock(&tmp->spinlock);
3224 if (tmp->type == DLM_MLE_MIGRATION) {
3225 if (master == dlm->node_num) {
3226 /* ah another process raced me to it */
3227 mlog(0, "tried to migrate %.*s, but some "
3228 "process beat me to it\n",
3229 namelen, name);
3230 spin_unlock(&tmp->spinlock);
3231 return -EEXIST;
3232 } else {
3233 /* bad. 2 NODES are trying to migrate! */
3234 mlog(ML_ERROR, "migration error mle: "
3235 "master=%u new_master=%u // request: "
3236 "master=%u new_master=%u // "
3237 "lockres=%.*s\n",
3238 tmp->master, tmp->new_master,
3239 master, new_master,
3240 namelen, name);
3241 BUG();
3243 } else {
3244 /* this is essentially what assert_master does */
3245 tmp->master = master;
3246 atomic_set(&tmp->woken, 1);
3247 wake_up(&tmp->wq);
3248 /* remove it so that only one mle will be found */
3249 __dlm_unlink_mle(dlm, tmp);
3250 __dlm_mle_detach_hb_events(dlm, tmp);
3251 if (tmp->type == DLM_MLE_MASTER) {
3252 ret = DLM_MIGRATE_RESPONSE_MASTERY_REF;
3253 mlog(0, "%s:%.*s: master=%u, newmaster=%u, "
3254 "telling master to get ref "
3255 "for cleared out mle during "
3256 "migration\n", dlm->name,
3257 namelen, name, master,
3258 new_master);
3261 spin_unlock(&tmp->spinlock);
3264 /* now add a migration mle to the tail of the list */
3265 dlm_init_mle(mle, DLM_MLE_MIGRATION, dlm, res, name, namelen);
3266 mle->new_master = new_master;
3267 /* the new master will be sending an assert master for this.
3268 * at that point we will get the refmap reference */
3269 mle->master = master;
3270 /* do this for consistency with other mle types */
3271 set_bit(new_master, mle->maybe_map);
3272 __dlm_insert_mle(dlm, mle);
3274 return ret;
3278 * Sets the owner of the lockres, associated to the mle, to UNKNOWN
3280 static struct dlm_lock_resource *dlm_reset_mleres_owner(struct dlm_ctxt *dlm,
3281 struct dlm_master_list_entry *mle)
3283 struct dlm_lock_resource *res;
3285 /* Find the lockres associated to the mle and set its owner to UNK */
3286 res = __dlm_lookup_lockres(dlm, mle->mname, mle->mnamelen,
3287 mle->mnamehash);
3288 if (res) {
3289 spin_unlock(&dlm->master_lock);
3291 /* move lockres onto recovery list */
3292 spin_lock(&res->spinlock);
3293 dlm_set_lockres_owner(dlm, res, DLM_LOCK_RES_OWNER_UNKNOWN);
3294 dlm_move_lockres_to_recovery_list(dlm, res);
3295 spin_unlock(&res->spinlock);
3296 dlm_lockres_put(res);
3298 /* about to get rid of mle, detach from heartbeat */
3299 __dlm_mle_detach_hb_events(dlm, mle);
3301 /* dump the mle */
3302 spin_lock(&dlm->master_lock);
3303 __dlm_put_mle(mle);
3304 spin_unlock(&dlm->master_lock);
3307 return res;
3310 static void dlm_clean_migration_mle(struct dlm_ctxt *dlm,
3311 struct dlm_master_list_entry *mle)
3313 __dlm_mle_detach_hb_events(dlm, mle);
3315 spin_lock(&mle->spinlock);
3316 __dlm_unlink_mle(dlm, mle);
3317 atomic_set(&mle->woken, 1);
3318 spin_unlock(&mle->spinlock);
3320 wake_up(&mle->wq);
3323 static void dlm_clean_block_mle(struct dlm_ctxt *dlm,
3324 struct dlm_master_list_entry *mle, u8 dead_node)
3326 int bit;
3328 BUG_ON(mle->type != DLM_MLE_BLOCK);
3330 spin_lock(&mle->spinlock);
3331 bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
3332 if (bit != dead_node) {
3333 mlog(0, "mle found, but dead node %u would not have been "
3334 "master\n", dead_node);
3335 spin_unlock(&mle->spinlock);
3336 } else {
3337 /* Must drop the refcount by one since the assert_master will
3338 * never arrive. This may result in the mle being unlinked and
3339 * freed, but there may still be a process waiting in the
3340 * dlmlock path which is fine. */
3341 mlog(0, "node %u was expected master\n", dead_node);
3342 atomic_set(&mle->woken, 1);
3343 spin_unlock(&mle->spinlock);
3344 wake_up(&mle->wq);
3346 /* Do not need events any longer, so detach from heartbeat */
3347 __dlm_mle_detach_hb_events(dlm, mle);
3348 __dlm_put_mle(mle);
3352 void dlm_clean_master_list(struct dlm_ctxt *dlm, u8 dead_node)
3354 struct dlm_master_list_entry *mle;
3355 struct dlm_lock_resource *res;
3356 struct hlist_head *bucket;
3357 struct hlist_node *tmp;
3358 unsigned int i;
3360 mlog(0, "dlm=%s, dead node=%u\n", dlm->name, dead_node);
3361 top:
3362 assert_spin_locked(&dlm->spinlock);
3364 /* clean the master list */
3365 spin_lock(&dlm->master_lock);
3366 for (i = 0; i < DLM_HASH_BUCKETS; i++) {
3367 bucket = dlm_master_hash(dlm, i);
3368 hlist_for_each_entry_safe(mle, tmp, bucket, master_hash_node) {
3369 BUG_ON(mle->type != DLM_MLE_BLOCK &&
3370 mle->type != DLM_MLE_MASTER &&
3371 mle->type != DLM_MLE_MIGRATION);
3373 /* MASTER mles are initiated locally. The waiting
3374 * process will notice the node map change shortly.
3375 * Let that happen as normal. */
3376 if (mle->type == DLM_MLE_MASTER)
3377 continue;
3379 /* BLOCK mles are initiated by other nodes. Need to
3380 * clean up if the dead node would have been the
3381 * master. */
3382 if (mle->type == DLM_MLE_BLOCK) {
3383 dlm_clean_block_mle(dlm, mle, dead_node);
3384 continue;
3387 /* Everything else is a MIGRATION mle */
3389 /* The rule for MIGRATION mles is that the master
3390 * becomes UNKNOWN if *either* the original or the new
3391 * master dies. All UNKNOWN lockres' are sent to
3392 * whichever node becomes the recovery master. The new
3393 * master is responsible for determining if there is
3394 * still a master for this lockres, or if he needs to
3395 * take over mastery. Either way, this node should
3396 * expect another message to resolve this. */
3398 if (mle->master != dead_node &&
3399 mle->new_master != dead_node)
3400 continue;
3402 if (mle->new_master == dead_node && mle->inuse) {
3403 mlog(ML_NOTICE, "%s: target %u died during "
3404 "migration from %u, the MLE is "
3405 "still keep used, ignore it!\n",
3406 dlm->name, dead_node,
3407 mle->master);
3408 continue;
3411 /* If we have reached this point, this mle needs to be
3412 * removed from the list and freed. */
3413 dlm_clean_migration_mle(dlm, mle);
3415 mlog(0, "%s: node %u died during migration from "
3416 "%u to %u!\n", dlm->name, dead_node, mle->master,
3417 mle->new_master);
3419 /* If we find a lockres associated with the mle, we've
3420 * hit this rare case that messes up our lock ordering.
3421 * If so, we need to drop the master lock so that we can
3422 * take the lockres lock, meaning that we will have to
3423 * restart from the head of list. */
3424 res = dlm_reset_mleres_owner(dlm, mle);
3425 if (res)
3426 /* restart */
3427 goto top;
3429 /* This may be the last reference */
3430 __dlm_put_mle(mle);
3433 spin_unlock(&dlm->master_lock);
3436 int dlm_finish_migration(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
3437 u8 old_master)
3439 struct dlm_node_iter iter;
3440 int ret = 0;
3442 spin_lock(&dlm->spinlock);
3443 dlm_node_iter_init(dlm->domain_map, &iter);
3444 clear_bit(old_master, iter.node_map);
3445 clear_bit(dlm->node_num, iter.node_map);
3446 spin_unlock(&dlm->spinlock);
3448 /* ownership of the lockres is changing. account for the
3449 * mastery reference here since old_master will briefly have
3450 * a reference after the migration completes */
3451 spin_lock(&res->spinlock);
3452 dlm_lockres_set_refmap_bit(dlm, res, old_master);
3453 spin_unlock(&res->spinlock);
3455 mlog(0, "now time to do a migrate request to other nodes\n");
3456 ret = dlm_do_migrate_request(dlm, res, old_master,
3457 dlm->node_num, &iter);
3458 if (ret < 0) {
3459 mlog_errno(ret);
3460 goto leave;
3463 mlog(0, "doing assert master of %.*s to all except the original node\n",
3464 res->lockname.len, res->lockname.name);
3465 /* this call now finishes out the nodemap
3466 * even if one or more nodes die */
3467 ret = dlm_do_assert_master(dlm, res, iter.node_map,
3468 DLM_ASSERT_MASTER_FINISH_MIGRATION);
3469 if (ret < 0) {
3470 /* no longer need to retry. all living nodes contacted. */
3471 mlog_errno(ret);
3472 ret = 0;
3475 memset(iter.node_map, 0, sizeof(iter.node_map));
3476 set_bit(old_master, iter.node_map);
3477 mlog(0, "doing assert master of %.*s back to %u\n",
3478 res->lockname.len, res->lockname.name, old_master);
3479 ret = dlm_do_assert_master(dlm, res, iter.node_map,
3480 DLM_ASSERT_MASTER_FINISH_MIGRATION);
3481 if (ret < 0) {
3482 mlog(0, "assert master to original master failed "
3483 "with %d.\n", ret);
3484 /* the only nonzero status here would be because of
3485 * a dead original node. we're done. */
3486 ret = 0;
3489 /* all done, set the owner, clear the flag */
3490 spin_lock(&res->spinlock);
3491 dlm_set_lockres_owner(dlm, res, dlm->node_num);
3492 res->state &= ~DLM_LOCK_RES_MIGRATING;
3493 spin_unlock(&res->spinlock);
3494 /* re-dirty it on the new master */
3495 dlm_kick_thread(dlm, res);
3496 wake_up(&res->wq);
3497 leave:
3498 return ret;
3502 * LOCKRES AST REFCOUNT
3503 * this is integral to migration
3506 /* for future intent to call an ast, reserve one ahead of time.
3507 * this should be called only after waiting on the lockres
3508 * with dlm_wait_on_lockres, and while still holding the
3509 * spinlock after the call. */
3510 void __dlm_lockres_reserve_ast(struct dlm_lock_resource *res)
3512 assert_spin_locked(&res->spinlock);
3513 if (res->state & DLM_LOCK_RES_MIGRATING) {
3514 __dlm_print_one_lock_resource(res);
3516 BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
3518 atomic_inc(&res->asts_reserved);
3522 * used to drop the reserved ast, either because it went unused,
3523 * or because the ast/bast was actually called.
3525 * also, if there is a pending migration on this lockres,
3526 * and this was the last pending ast on the lockres,
3527 * atomically set the MIGRATING flag before we drop the lock.
3528 * this is how we ensure that migration can proceed with no
3529 * asts in progress. note that it is ok if the state of the
3530 * queues is such that a lock should be granted in the future
3531 * or that a bast should be fired, because the new master will
3532 * shuffle the lists on this lockres as soon as it is migrated.
3534 void dlm_lockres_release_ast(struct dlm_ctxt *dlm,
3535 struct dlm_lock_resource *res)
3537 if (!atomic_dec_and_lock(&res->asts_reserved, &res->spinlock))
3538 return;
3540 if (!res->migration_pending) {
3541 spin_unlock(&res->spinlock);
3542 return;
3545 BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
3546 res->migration_pending = 0;
3547 res->state |= DLM_LOCK_RES_MIGRATING;
3548 spin_unlock(&res->spinlock);
3549 wake_up(&res->wq);
3550 wake_up(&dlm->migration_wq);
3553 void dlm_force_free_mles(struct dlm_ctxt *dlm)
3555 int i;
3556 struct hlist_head *bucket;
3557 struct dlm_master_list_entry *mle;
3558 struct hlist_node *tmp;
3561 * We notified all other nodes that we are exiting the domain and
3562 * marked the dlm state to DLM_CTXT_LEAVING. If any mles are still
3563 * around we force free them and wake any processes that are waiting
3564 * on the mles
3566 spin_lock(&dlm->spinlock);
3567 spin_lock(&dlm->master_lock);
3569 BUG_ON(dlm->dlm_state != DLM_CTXT_LEAVING);
3570 BUG_ON((find_next_bit(dlm->domain_map, O2NM_MAX_NODES, 0) < O2NM_MAX_NODES));
3572 for (i = 0; i < DLM_HASH_BUCKETS; i++) {
3573 bucket = dlm_master_hash(dlm, i);
3574 hlist_for_each_entry_safe(mle, tmp, bucket, master_hash_node) {
3575 if (mle->type != DLM_MLE_BLOCK) {
3576 mlog(ML_ERROR, "bad mle: %p\n", mle);
3577 dlm_print_one_mle(mle);
3579 atomic_set(&mle->woken, 1);
3580 wake_up(&mle->wq);
3582 __dlm_unlink_mle(dlm, mle);
3583 __dlm_mle_detach_hb_events(dlm, mle);
3584 __dlm_put_mle(mle);
3587 spin_unlock(&dlm->master_lock);
3588 spin_unlock(&dlm->spinlock);