1 /* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
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>
30 #include <linux/types.h>
31 #include <linux/slab.h>
32 #include <linux/highmem.h>
33 #include <linux/utsname.h>
34 #include <linux/init.h>
35 #include <linux/sysctl.h>
36 #include <linux/random.h>
37 #include <linux/blkdev.h>
38 #include <linux/socket.h>
39 #include <linux/inet.h>
40 #include <linux/spinlock.h>
41 #include <linux/delay.h>
44 #include "cluster/heartbeat.h"
45 #include "cluster/nodemanager.h"
46 #include "cluster/tcp.h"
49 #include "dlmcommon.h"
51 #include "dlmdomain.h"
53 #define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_MASTER)
54 #include "cluster/masklog.h"
65 u8 name[DLM_LOCKID_NAME_MAX];
68 struct dlm_master_list_entry
70 struct list_head list;
71 struct list_head hb_events;
78 unsigned long maybe_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
79 unsigned long vote_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
80 unsigned long response_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
81 unsigned long node_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
84 enum dlm_mle_type type;
85 struct o2hb_callback_func mle_hb_up;
86 struct o2hb_callback_func mle_hb_down;
88 struct dlm_lock_resource *res;
89 struct dlm_lock_name name;
93 static void dlm_mle_node_down(struct dlm_ctxt *dlm,
94 struct dlm_master_list_entry *mle,
95 struct o2nm_node *node,
97 static void dlm_mle_node_up(struct dlm_ctxt *dlm,
98 struct dlm_master_list_entry *mle,
99 struct o2nm_node *node,
102 static void dlm_assert_master_worker(struct dlm_work_item *item, void *data);
103 static int dlm_do_assert_master(struct dlm_ctxt *dlm, const char *lockname,
104 unsigned int namelen, void *nodemap,
107 static inline int dlm_mle_equal(struct dlm_ctxt *dlm,
108 struct dlm_master_list_entry *mle,
110 unsigned int namelen)
112 struct dlm_lock_resource *res;
117 if (mle->type == DLM_MLE_BLOCK ||
118 mle->type == DLM_MLE_MIGRATION) {
119 if (namelen != mle->u.name.len ||
120 memcmp(name, mle->u.name.name, namelen)!=0)
124 if (namelen != res->lockname.len ||
125 memcmp(res->lockname.name, name, namelen) != 0)
132 /* Code here is included but defined out as it aids debugging */
134 #define dlm_print_nodemap(m) _dlm_print_nodemap(m,#m)
135 void _dlm_print_nodemap(unsigned long *map, const char *mapname)
138 printk("%s=[ ", mapname);
139 for (i=0; i<O2NM_MAX_NODES; i++)
140 if (test_bit(i, map))
145 void dlm_print_one_mle(struct dlm_master_list_entry *mle)
151 unsigned int namelen;
154 unsigned long *maybe = mle->maybe_map,
155 *vote = mle->vote_map,
156 *resp = mle->response_map,
157 *node = mle->node_map;
160 if (mle->type == DLM_MLE_BLOCK)
162 else if (mle->type == DLM_MLE_MASTER)
166 refs = atomic_read(&k->refcount);
167 master = mle->master;
168 attached = (list_empty(&mle->hb_events) ? 'N' : 'Y');
170 if (mle->type != DLM_MLE_MASTER) {
171 namelen = mle->u.name.len;
172 name = mle->u.name.name;
174 namelen = mle->u.res->lockname.len;
175 name = mle->u.res->lockname.name;
178 mlog(ML_NOTICE, "%.*s: %3s refs=%3d mas=%3u new=%3u evt=%c inuse=%d ",
179 namelen, name, type, refs, master, mle->new_master, attached,
181 dlm_print_nodemap(maybe);
183 dlm_print_nodemap(vote);
185 dlm_print_nodemap(resp);
187 dlm_print_nodemap(node);
192 static void dlm_dump_mles(struct dlm_ctxt *dlm)
194 struct dlm_master_list_entry *mle;
195 struct list_head *iter;
197 mlog(ML_NOTICE, "dumping all mles for domain %s:\n", dlm->name);
198 spin_lock(&dlm->master_lock);
199 list_for_each(iter, &dlm->master_list) {
200 mle = list_entry(iter, struct dlm_master_list_entry, list);
201 dlm_print_one_mle(mle);
203 spin_unlock(&dlm->master_lock);
206 int dlm_dump_all_mles(const char __user *data, unsigned int len)
208 struct list_head *iter;
209 struct dlm_ctxt *dlm;
211 spin_lock(&dlm_domain_lock);
212 list_for_each(iter, &dlm_domains) {
213 dlm = list_entry (iter, struct dlm_ctxt, list);
214 mlog(ML_NOTICE, "found dlm: %p, name=%s\n", dlm, dlm->name);
217 spin_unlock(&dlm_domain_lock);
220 EXPORT_SYMBOL_GPL(dlm_dump_all_mles);
225 static kmem_cache_t *dlm_mle_cache = NULL;
228 static void dlm_mle_release(struct kref *kref);
229 static void dlm_init_mle(struct dlm_master_list_entry *mle,
230 enum dlm_mle_type type,
231 struct dlm_ctxt *dlm,
232 struct dlm_lock_resource *res,
234 unsigned int namelen);
235 static void dlm_put_mle(struct dlm_master_list_entry *mle);
236 static void __dlm_put_mle(struct dlm_master_list_entry *mle);
237 static int dlm_find_mle(struct dlm_ctxt *dlm,
238 struct dlm_master_list_entry **mle,
239 char *name, unsigned int namelen);
241 static int dlm_do_master_request(struct dlm_master_list_entry *mle, int to);
244 static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
245 struct dlm_lock_resource *res,
246 struct dlm_master_list_entry *mle,
248 static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
249 struct dlm_lock_resource *res,
250 struct dlm_master_list_entry *mle,
252 static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
253 struct dlm_lock_resource *res,
254 struct dlm_master_list_entry *mle,
255 struct dlm_master_list_entry **oldmle,
256 const char *name, unsigned int namelen,
257 u8 new_master, u8 master);
259 static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
260 struct dlm_lock_resource *res);
261 static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
262 struct dlm_lock_resource *res);
263 static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
264 struct dlm_lock_resource *res,
266 static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
267 struct dlm_lock_resource *res);
270 int dlm_is_host_down(int errno)
287 case -EINVAL: /* if returned from our tcp code,
288 this means there is no socket */
296 * MASTER LIST FUNCTIONS
301 * regarding master list entries and heartbeat callbacks:
303 * in order to avoid sleeping and allocation that occurs in
304 * heartbeat, master list entries are simply attached to the
305 * dlm's established heartbeat callbacks. the mle is attached
306 * when it is created, and since the dlm->spinlock is held at
307 * that time, any heartbeat event will be properly discovered
308 * by the mle. the mle needs to be detached from the
309 * dlm->mle_hb_events list as soon as heartbeat events are no
310 * longer useful to the mle, and before the mle is freed.
312 * as a general rule, heartbeat events are no longer needed by
313 * the mle once an "answer" regarding the lock master has been
316 static inline void __dlm_mle_attach_hb_events(struct dlm_ctxt *dlm,
317 struct dlm_master_list_entry *mle)
319 assert_spin_locked(&dlm->spinlock);
321 list_add_tail(&mle->hb_events, &dlm->mle_hb_events);
325 static inline void __dlm_mle_detach_hb_events(struct dlm_ctxt *dlm,
326 struct dlm_master_list_entry *mle)
328 if (!list_empty(&mle->hb_events))
329 list_del_init(&mle->hb_events);
333 static inline void dlm_mle_detach_hb_events(struct dlm_ctxt *dlm,
334 struct dlm_master_list_entry *mle)
336 spin_lock(&dlm->spinlock);
337 __dlm_mle_detach_hb_events(dlm, mle);
338 spin_unlock(&dlm->spinlock);
341 static void dlm_get_mle_inuse(struct dlm_master_list_entry *mle)
343 struct dlm_ctxt *dlm;
346 assert_spin_locked(&dlm->spinlock);
347 assert_spin_locked(&dlm->master_lock);
349 kref_get(&mle->mle_refs);
352 static void dlm_put_mle_inuse(struct dlm_master_list_entry *mle)
354 struct dlm_ctxt *dlm;
357 spin_lock(&dlm->spinlock);
358 spin_lock(&dlm->master_lock);
361 spin_unlock(&dlm->master_lock);
362 spin_unlock(&dlm->spinlock);
366 /* remove from list and free */
367 static void __dlm_put_mle(struct dlm_master_list_entry *mle)
369 struct dlm_ctxt *dlm;
372 assert_spin_locked(&dlm->spinlock);
373 assert_spin_locked(&dlm->master_lock);
374 BUG_ON(!atomic_read(&mle->mle_refs.refcount));
376 kref_put(&mle->mle_refs, dlm_mle_release);
380 /* must not have any spinlocks coming in */
381 static void dlm_put_mle(struct dlm_master_list_entry *mle)
383 struct dlm_ctxt *dlm;
386 spin_lock(&dlm->spinlock);
387 spin_lock(&dlm->master_lock);
389 spin_unlock(&dlm->master_lock);
390 spin_unlock(&dlm->spinlock);
393 static inline void dlm_get_mle(struct dlm_master_list_entry *mle)
395 kref_get(&mle->mle_refs);
398 static void dlm_init_mle(struct dlm_master_list_entry *mle,
399 enum dlm_mle_type type,
400 struct dlm_ctxt *dlm,
401 struct dlm_lock_resource *res,
403 unsigned int namelen)
405 assert_spin_locked(&dlm->spinlock);
409 INIT_LIST_HEAD(&mle->list);
410 INIT_LIST_HEAD(&mle->hb_events);
411 memset(mle->maybe_map, 0, sizeof(mle->maybe_map));
412 spin_lock_init(&mle->spinlock);
413 init_waitqueue_head(&mle->wq);
414 atomic_set(&mle->woken, 0);
415 kref_init(&mle->mle_refs);
416 memset(mle->response_map, 0, sizeof(mle->response_map));
417 mle->master = O2NM_MAX_NODES;
418 mle->new_master = O2NM_MAX_NODES;
421 if (mle->type == DLM_MLE_MASTER) {
424 } else if (mle->type == DLM_MLE_BLOCK) {
426 memcpy(mle->u.name.name, name, namelen);
427 mle->u.name.len = namelen;
428 } else /* DLM_MLE_MIGRATION */ {
430 memcpy(mle->u.name.name, name, namelen);
431 mle->u.name.len = namelen;
434 /* copy off the node_map and register hb callbacks on our copy */
435 memcpy(mle->node_map, dlm->domain_map, sizeof(mle->node_map));
436 memcpy(mle->vote_map, dlm->domain_map, sizeof(mle->vote_map));
437 clear_bit(dlm->node_num, mle->vote_map);
438 clear_bit(dlm->node_num, mle->node_map);
440 /* attach the mle to the domain node up/down events */
441 __dlm_mle_attach_hb_events(dlm, mle);
445 /* returns 1 if found, 0 if not */
446 static int dlm_find_mle(struct dlm_ctxt *dlm,
447 struct dlm_master_list_entry **mle,
448 char *name, unsigned int namelen)
450 struct dlm_master_list_entry *tmpmle;
451 struct list_head *iter;
453 assert_spin_locked(&dlm->master_lock);
455 list_for_each(iter, &dlm->master_list) {
456 tmpmle = list_entry(iter, struct dlm_master_list_entry, list);
457 if (!dlm_mle_equal(dlm, tmpmle, name, namelen))
466 void dlm_hb_event_notify_attached(struct dlm_ctxt *dlm, int idx, int node_up)
468 struct dlm_master_list_entry *mle;
469 struct list_head *iter;
471 assert_spin_locked(&dlm->spinlock);
473 list_for_each(iter, &dlm->mle_hb_events) {
474 mle = list_entry(iter, struct dlm_master_list_entry,
477 dlm_mle_node_up(dlm, mle, NULL, idx);
479 dlm_mle_node_down(dlm, mle, NULL, idx);
483 static void dlm_mle_node_down(struct dlm_ctxt *dlm,
484 struct dlm_master_list_entry *mle,
485 struct o2nm_node *node, int idx)
487 spin_lock(&mle->spinlock);
489 if (!test_bit(idx, mle->node_map))
490 mlog(0, "node %u already removed from nodemap!\n", idx);
492 clear_bit(idx, mle->node_map);
494 spin_unlock(&mle->spinlock);
497 static void dlm_mle_node_up(struct dlm_ctxt *dlm,
498 struct dlm_master_list_entry *mle,
499 struct o2nm_node *node, int idx)
501 spin_lock(&mle->spinlock);
503 if (test_bit(idx, mle->node_map))
504 mlog(0, "node %u already in node map!\n", idx);
506 set_bit(idx, mle->node_map);
508 spin_unlock(&mle->spinlock);
512 int dlm_init_mle_cache(void)
514 dlm_mle_cache = kmem_cache_create("dlm_mle_cache",
515 sizeof(struct dlm_master_list_entry),
516 0, SLAB_HWCACHE_ALIGN,
518 if (dlm_mle_cache == NULL)
523 void dlm_destroy_mle_cache(void)
526 kmem_cache_destroy(dlm_mle_cache);
529 static void dlm_mle_release(struct kref *kref)
531 struct dlm_master_list_entry *mle;
532 struct dlm_ctxt *dlm;
536 mle = container_of(kref, struct dlm_master_list_entry, mle_refs);
539 if (mle->type != DLM_MLE_MASTER) {
540 mlog(0, "calling mle_release for %.*s, type %d\n",
541 mle->u.name.len, mle->u.name.name, mle->type);
543 mlog(0, "calling mle_release for %.*s, type %d\n",
544 mle->u.res->lockname.len,
545 mle->u.res->lockname.name, mle->type);
547 assert_spin_locked(&dlm->spinlock);
548 assert_spin_locked(&dlm->master_lock);
550 /* remove from list if not already */
551 if (!list_empty(&mle->list))
552 list_del_init(&mle->list);
554 /* detach the mle from the domain node up/down events */
555 __dlm_mle_detach_hb_events(dlm, mle);
557 /* NOTE: kfree under spinlock here.
558 * if this is bad, we can move this to a freelist. */
559 kmem_cache_free(dlm_mle_cache, mle);
564 * LOCK RESOURCE FUNCTIONS
567 static void dlm_set_lockres_owner(struct dlm_ctxt *dlm,
568 struct dlm_lock_resource *res,
571 assert_spin_locked(&res->spinlock);
573 mlog_entry("%.*s, %u\n", res->lockname.len, res->lockname.name, owner);
575 if (owner == dlm->node_num)
576 atomic_inc(&dlm->local_resources);
577 else if (owner == DLM_LOCK_RES_OWNER_UNKNOWN)
578 atomic_inc(&dlm->unknown_resources);
580 atomic_inc(&dlm->remote_resources);
585 void dlm_change_lockres_owner(struct dlm_ctxt *dlm,
586 struct dlm_lock_resource *res, u8 owner)
588 assert_spin_locked(&res->spinlock);
590 if (owner == res->owner)
593 if (res->owner == dlm->node_num)
594 atomic_dec(&dlm->local_resources);
595 else if (res->owner == DLM_LOCK_RES_OWNER_UNKNOWN)
596 atomic_dec(&dlm->unknown_resources);
598 atomic_dec(&dlm->remote_resources);
600 dlm_set_lockres_owner(dlm, res, owner);
604 static void dlm_lockres_release(struct kref *kref)
606 struct dlm_lock_resource *res;
608 res = container_of(kref, struct dlm_lock_resource, refs);
610 /* This should not happen -- all lockres' have a name
611 * associated with them at init time. */
612 BUG_ON(!res->lockname.name);
614 mlog(0, "destroying lockres %.*s\n", res->lockname.len,
617 /* By the time we're ready to blow this guy away, we shouldn't
618 * be on any lists. */
619 BUG_ON(!hlist_unhashed(&res->hash_node));
620 BUG_ON(!list_empty(&res->granted));
621 BUG_ON(!list_empty(&res->converting));
622 BUG_ON(!list_empty(&res->blocked));
623 BUG_ON(!list_empty(&res->dirty));
624 BUG_ON(!list_empty(&res->recovering));
625 BUG_ON(!list_empty(&res->purge));
627 kfree(res->lockname.name);
632 void dlm_lockres_put(struct dlm_lock_resource *res)
634 kref_put(&res->refs, dlm_lockres_release);
637 static void dlm_init_lockres(struct dlm_ctxt *dlm,
638 struct dlm_lock_resource *res,
639 const char *name, unsigned int namelen)
643 /* If we memset here, we lose our reference to the kmalloc'd
644 * res->lockname.name, so be sure to init every field
647 qname = (char *) res->lockname.name;
648 memcpy(qname, name, namelen);
650 res->lockname.len = namelen;
651 res->lockname.hash = dlm_lockid_hash(name, namelen);
653 init_waitqueue_head(&res->wq);
654 spin_lock_init(&res->spinlock);
655 INIT_HLIST_NODE(&res->hash_node);
656 INIT_LIST_HEAD(&res->granted);
657 INIT_LIST_HEAD(&res->converting);
658 INIT_LIST_HEAD(&res->blocked);
659 INIT_LIST_HEAD(&res->dirty);
660 INIT_LIST_HEAD(&res->recovering);
661 INIT_LIST_HEAD(&res->purge);
662 atomic_set(&res->asts_reserved, 0);
663 res->migration_pending = 0;
665 kref_init(&res->refs);
667 /* just for consistency */
668 spin_lock(&res->spinlock);
669 dlm_set_lockres_owner(dlm, res, DLM_LOCK_RES_OWNER_UNKNOWN);
670 spin_unlock(&res->spinlock);
672 res->state = DLM_LOCK_RES_IN_PROGRESS;
676 memset(res->lvb, 0, DLM_LVB_LEN);
679 struct dlm_lock_resource *dlm_new_lockres(struct dlm_ctxt *dlm,
681 unsigned int namelen)
683 struct dlm_lock_resource *res;
685 res = kmalloc(sizeof(struct dlm_lock_resource), GFP_KERNEL);
689 res->lockname.name = kmalloc(namelen, GFP_KERNEL);
690 if (!res->lockname.name) {
695 dlm_init_lockres(dlm, res, name, namelen);
700 * lookup a lock resource by name.
701 * may already exist in the hashtable.
702 * lockid is null terminated
704 * if not, allocate enough for the lockres and for
705 * the temporary structure used in doing the mastering.
707 * also, do a lookup in the dlm->master_list to see
708 * if another node has begun mastering the same lock.
709 * if so, there should be a block entry in there
710 * for this name, and we should *not* attempt to master
711 * the lock here. need to wait around for that node
712 * to assert_master (or die).
715 struct dlm_lock_resource * dlm_get_lock_resource(struct dlm_ctxt *dlm,
719 struct dlm_lock_resource *tmpres=NULL, *res=NULL;
720 struct dlm_master_list_entry *mle = NULL;
721 struct dlm_master_list_entry *alloc_mle = NULL;
724 struct dlm_node_iter iter;
725 unsigned int namelen, hash;
727 int bit, wait_on_recovery = 0;
731 namelen = strlen(lockid);
732 hash = dlm_lockid_hash(lockid, namelen);
734 mlog(0, "get lockres %s (len %d)\n", lockid, namelen);
737 spin_lock(&dlm->spinlock);
738 tmpres = __dlm_lookup_lockres(dlm, lockid, namelen, hash);
740 spin_unlock(&dlm->spinlock);
741 mlog(0, "found in hash!\n");
743 dlm_lockres_put(res);
749 spin_unlock(&dlm->spinlock);
750 mlog(0, "allocating a new resource\n");
751 /* nothing found and we need to allocate one. */
752 alloc_mle = (struct dlm_master_list_entry *)
753 kmem_cache_alloc(dlm_mle_cache, GFP_KERNEL);
756 res = dlm_new_lockres(dlm, lockid, namelen);
762 mlog(0, "no lockres found, allocated our own: %p\n", res);
764 if (flags & LKM_LOCAL) {
765 /* caller knows it's safe to assume it's not mastered elsewhere
766 * DONE! return right away */
767 spin_lock(&res->spinlock);
768 dlm_change_lockres_owner(dlm, res, dlm->node_num);
769 __dlm_insert_lockres(dlm, res);
770 spin_unlock(&res->spinlock);
771 spin_unlock(&dlm->spinlock);
772 /* lockres still marked IN_PROGRESS */
776 /* check master list to see if another node has started mastering it */
777 spin_lock(&dlm->master_lock);
779 /* if we found a block, wait for lock to be mastered by another node */
780 blocked = dlm_find_mle(dlm, &mle, (char *)lockid, namelen);
782 if (mle->type == DLM_MLE_MASTER) {
783 mlog(ML_ERROR, "master entry for nonexistent lock!\n");
785 } else if (mle->type == DLM_MLE_MIGRATION) {
786 /* migration is in progress! */
787 /* the good news is that we now know the
788 * "current" master (mle->master). */
790 spin_unlock(&dlm->master_lock);
791 assert_spin_locked(&dlm->spinlock);
793 /* set the lockres owner and hash it */
794 spin_lock(&res->spinlock);
795 dlm_set_lockres_owner(dlm, res, mle->master);
796 __dlm_insert_lockres(dlm, res);
797 spin_unlock(&res->spinlock);
798 spin_unlock(&dlm->spinlock);
800 /* master is known, detach */
801 dlm_mle_detach_hb_events(dlm, mle);
807 /* go ahead and try to master lock on this node */
809 /* make sure this does not get freed below */
811 dlm_init_mle(mle, DLM_MLE_MASTER, dlm, res, NULL, 0);
812 set_bit(dlm->node_num, mle->maybe_map);
813 list_add(&mle->list, &dlm->master_list);
815 /* still holding the dlm spinlock, check the recovery map
816 * to see if there are any nodes that still need to be
817 * considered. these will not appear in the mle nodemap
818 * but they might own this lockres. wait on them. */
819 bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
820 if (bit < O2NM_MAX_NODES) {
821 mlog(ML_NOTICE, "%s:%.*s: at least one node (%d) to"
822 "recover before lock mastery can begin\n",
823 dlm->name, namelen, (char *)lockid, bit);
824 wait_on_recovery = 1;
828 /* at this point there is either a DLM_MLE_BLOCK or a
829 * DLM_MLE_MASTER on the master list, so it's safe to add the
830 * lockres to the hashtable. anyone who finds the lock will
831 * still have to wait on the IN_PROGRESS. */
833 /* finally add the lockres to its hash bucket */
834 __dlm_insert_lockres(dlm, res);
835 /* get an extra ref on the mle in case this is a BLOCK
836 * if so, the creator of the BLOCK may try to put the last
837 * ref at this time in the assert master handler, so we
838 * need an extra one to keep from a bad ptr deref. */
839 dlm_get_mle_inuse(mle);
840 spin_unlock(&dlm->master_lock);
841 spin_unlock(&dlm->spinlock);
843 while (wait_on_recovery) {
844 /* any cluster changes that occurred after dropping the
845 * dlm spinlock would be detectable be a change on the mle,
846 * so we only need to clear out the recovery map once. */
847 if (dlm_is_recovery_lock(lockid, namelen)) {
848 mlog(ML_NOTICE, "%s: recovery map is not empty, but "
849 "must master $RECOVERY lock now\n", dlm->name);
850 if (!dlm_pre_master_reco_lockres(dlm, res))
851 wait_on_recovery = 0;
853 mlog(0, "%s: waiting 500ms for heartbeat state "
854 "change\n", dlm->name);
860 dlm_kick_recovery_thread(dlm);
862 dlm_wait_for_recovery(dlm);
864 spin_lock(&dlm->spinlock);
865 bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
866 if (bit < O2NM_MAX_NODES) {
867 mlog(ML_NOTICE, "%s:%.*s: at least one node (%d) to"
868 "recover before lock mastery can begin\n",
869 dlm->name, namelen, (char *)lockid, bit);
870 wait_on_recovery = 1;
872 wait_on_recovery = 0;
873 spin_unlock(&dlm->spinlock);
876 /* must wait for lock to be mastered elsewhere */
882 dlm_node_iter_init(mle->vote_map, &iter);
883 while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
884 ret = dlm_do_master_request(mle, nodenum);
887 if (mle->master != O2NM_MAX_NODES) {
888 /* found a master ! */
889 if (mle->master <= nodenum)
891 /* if our master request has not reached the master
892 * yet, keep going until it does. this is how the
893 * master will know that asserts are needed back to
894 * the lower nodes. */
895 mlog(0, "%s:%.*s: requests only up to %u but master "
896 "is %u, keep going\n", dlm->name, namelen,
897 lockid, nodenum, mle->master);
902 /* keep going until the response map includes all nodes */
903 ret = dlm_wait_for_lock_mastery(dlm, res, mle, &blocked);
905 mlog(0, "%s:%.*s: node map changed, redo the "
906 "master request now, blocked=%d\n",
907 dlm->name, res->lockname.len,
908 res->lockname.name, blocked);
910 mlog(ML_ERROR, "%s:%.*s: spinning on "
911 "dlm_wait_for_lock_mastery, blocked=%d\n",
912 dlm->name, res->lockname.len,
913 res->lockname.name, blocked);
914 dlm_print_one_lock_resource(res);
915 /* dlm_print_one_mle(mle); */
921 mlog(0, "lockres mastered by %u\n", res->owner);
922 /* make sure we never continue without this */
923 BUG_ON(res->owner == O2NM_MAX_NODES);
925 /* master is known, detach if not already detached */
926 dlm_mle_detach_hb_events(dlm, mle);
928 /* put the extra ref */
929 dlm_put_mle_inuse(mle);
932 spin_lock(&res->spinlock);
933 res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
934 spin_unlock(&res->spinlock);
938 /* need to free the unused mle */
940 kmem_cache_free(dlm_mle_cache, alloc_mle);
946 #define DLM_MASTERY_TIMEOUT_MS 5000
948 static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
949 struct dlm_lock_resource *res,
950 struct dlm_master_list_entry *mle,
955 int map_changed, voting_done;
962 /* check if another node has already become the owner */
963 spin_lock(&res->spinlock);
964 if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
965 mlog(0, "%s:%.*s: owner is suddenly %u\n", dlm->name,
966 res->lockname.len, res->lockname.name, res->owner);
967 spin_unlock(&res->spinlock);
968 /* this will cause the master to re-assert across
969 * the whole cluster, freeing up mles */
970 ret = dlm_do_master_request(mle, res->owner);
972 /* give recovery a chance to run */
973 mlog(ML_ERROR, "link to %u went down?: %d\n", res->owner, ret);
980 spin_unlock(&res->spinlock);
982 spin_lock(&mle->spinlock);
984 map_changed = (memcmp(mle->vote_map, mle->node_map,
985 sizeof(mle->vote_map)) != 0);
986 voting_done = (memcmp(mle->vote_map, mle->response_map,
987 sizeof(mle->vote_map)) == 0);
989 /* restart if we hit any errors */
992 mlog(0, "%s: %.*s: node map changed, restarting\n",
993 dlm->name, res->lockname.len, res->lockname.name);
994 ret = dlm_restart_lock_mastery(dlm, res, mle, *blocked);
995 b = (mle->type == DLM_MLE_BLOCK);
996 if ((*blocked && !b) || (!*blocked && b)) {
997 mlog(0, "%s:%.*s: status change: old=%d new=%d\n",
998 dlm->name, res->lockname.len, res->lockname.name,
1002 spin_unlock(&mle->spinlock);
1007 mlog(0, "%s:%.*s: restart lock mastery succeeded, "
1008 "rechecking now\n", dlm->name, res->lockname.len,
1009 res->lockname.name);
1013 if (m != O2NM_MAX_NODES) {
1014 /* another node has done an assert!
1019 /* have all nodes responded? */
1020 if (voting_done && !*blocked) {
1021 bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
1022 if (dlm->node_num <= bit) {
1023 /* my node number is lowest.
1024 * now tell other nodes that I am
1025 * mastering this. */
1026 mle->master = dlm->node_num;
1030 /* if voting is done, but we have not received
1031 * an assert master yet, we must sleep */
1035 spin_unlock(&mle->spinlock);
1037 /* sleep if we haven't finished voting yet */
1039 unsigned long timeo = msecs_to_jiffies(DLM_MASTERY_TIMEOUT_MS);
1042 if (atomic_read(&mle->mle_refs.refcount) < 2)
1043 mlog(ML_ERROR, "mle (%p) refs=%d, name=%.*s\n", mle,
1044 atomic_read(&mle->mle_refs.refcount),
1045 res->lockname.len, res->lockname.name);
1047 atomic_set(&mle->woken, 0);
1048 (void)wait_event_timeout(mle->wq,
1049 (atomic_read(&mle->woken) == 1),
1051 if (res->owner == O2NM_MAX_NODES) {
1052 mlog(0, "waiting again\n");
1055 mlog(0, "done waiting, master is %u\n", res->owner);
1063 mlog(0, "about to master %.*s here, this=%u\n",
1064 res->lockname.len, res->lockname.name, m);
1065 ret = dlm_do_assert_master(dlm, res->lockname.name,
1066 res->lockname.len, mle->vote_map, 0);
1068 /* This is a failure in the network path,
1069 * not in the response to the assert_master
1070 * (any nonzero response is a BUG on this node).
1071 * Most likely a socket just got disconnected
1072 * due to node death. */
1075 /* no longer need to restart lock mastery.
1076 * all living nodes have been contacted. */
1080 /* set the lockres owner */
1081 spin_lock(&res->spinlock);
1082 dlm_change_lockres_owner(dlm, res, m);
1083 spin_unlock(&res->spinlock);
1089 struct dlm_bitmap_diff_iter
1092 unsigned long *orig_bm;
1093 unsigned long *cur_bm;
1094 unsigned long diff_bm[BITS_TO_LONGS(O2NM_MAX_NODES)];
1097 enum dlm_node_state_change
1104 static void dlm_bitmap_diff_iter_init(struct dlm_bitmap_diff_iter *iter,
1105 unsigned long *orig_bm,
1106 unsigned long *cur_bm)
1108 unsigned long p1, p2;
1112 iter->orig_bm = orig_bm;
1113 iter->cur_bm = cur_bm;
1115 for (i = 0; i < BITS_TO_LONGS(O2NM_MAX_NODES); i++) {
1116 p1 = *(iter->orig_bm + i);
1117 p2 = *(iter->cur_bm + i);
1118 iter->diff_bm[i] = (p1 & ~p2) | (p2 & ~p1);
1122 static int dlm_bitmap_diff_iter_next(struct dlm_bitmap_diff_iter *iter,
1123 enum dlm_node_state_change *state)
1127 if (iter->curnode >= O2NM_MAX_NODES)
1130 bit = find_next_bit(iter->diff_bm, O2NM_MAX_NODES,
1132 if (bit >= O2NM_MAX_NODES) {
1133 iter->curnode = O2NM_MAX_NODES;
1137 /* if it was there in the original then this node died */
1138 if (test_bit(bit, iter->orig_bm))
1143 iter->curnode = bit;
1148 static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
1149 struct dlm_lock_resource *res,
1150 struct dlm_master_list_entry *mle,
1153 struct dlm_bitmap_diff_iter bdi;
1154 enum dlm_node_state_change sc;
1158 mlog(0, "something happened such that the "
1159 "master process may need to be restarted!\n");
1161 assert_spin_locked(&mle->spinlock);
1163 dlm_bitmap_diff_iter_init(&bdi, mle->vote_map, mle->node_map);
1164 node = dlm_bitmap_diff_iter_next(&bdi, &sc);
1166 if (sc == NODE_UP) {
1167 /* a node came up. clear any old vote from
1168 * the response map and set it in the vote map
1169 * then restart the mastery. */
1170 mlog(ML_NOTICE, "node %d up while restarting\n", node);
1172 /* redo the master request, but only for the new node */
1173 mlog(0, "sending request to new node\n");
1174 clear_bit(node, mle->response_map);
1175 set_bit(node, mle->vote_map);
1177 mlog(ML_ERROR, "node down! %d\n", node);
1179 /* if the node wasn't involved in mastery skip it,
1180 * but clear it out from the maps so that it will
1181 * not affect mastery of this lockres */
1182 clear_bit(node, mle->response_map);
1183 clear_bit(node, mle->vote_map);
1184 if (!test_bit(node, mle->maybe_map))
1187 /* if we're already blocked on lock mastery, and the
1188 * dead node wasn't the expected master, or there is
1189 * another node in the maybe_map, keep waiting */
1191 int lowest = find_next_bit(mle->maybe_map,
1194 /* act like it was never there */
1195 clear_bit(node, mle->maybe_map);
1200 mlog(ML_ERROR, "expected master %u died while "
1201 "this node was blocked waiting on it!\n",
1203 lowest = find_next_bit(mle->maybe_map,
1206 if (lowest < O2NM_MAX_NODES) {
1207 mlog(0, "still blocked. waiting "
1208 "on %u now\n", lowest);
1212 /* mle is an MLE_BLOCK, but there is now
1213 * nothing left to block on. we need to return
1214 * all the way back out and try again with
1215 * an MLE_MASTER. dlm_do_local_recovery_cleanup
1216 * has already run, so the mle refcount is ok */
1217 mlog(0, "no longer blocking. we can "
1218 "try to master this here\n");
1219 mle->type = DLM_MLE_MASTER;
1220 memset(mle->maybe_map, 0,
1221 sizeof(mle->maybe_map));
1222 memset(mle->response_map, 0,
1223 sizeof(mle->maybe_map));
1224 memcpy(mle->vote_map, mle->node_map,
1225 sizeof(mle->node_map));
1227 set_bit(dlm->node_num, mle->maybe_map);
1233 clear_bit(node, mle->maybe_map);
1234 if (node > dlm->node_num)
1237 mlog(0, "dead node in map!\n");
1238 /* yuck. go back and re-contact all nodes
1239 * in the vote_map, removing this node. */
1240 memset(mle->response_map, 0,
1241 sizeof(mle->response_map));
1245 node = dlm_bitmap_diff_iter_next(&bdi, &sc);
1252 * DLM_MASTER_REQUEST_MSG
1254 * returns: 0 on success,
1255 * -errno on a network error
1257 * on error, the caller should assume the target node is "dead"
1261 static int dlm_do_master_request(struct dlm_master_list_entry *mle, int to)
1263 struct dlm_ctxt *dlm = mle->dlm;
1264 struct dlm_master_request request;
1265 int ret, response=0, resend;
1267 memset(&request, 0, sizeof(request));
1268 request.node_idx = dlm->node_num;
1270 BUG_ON(mle->type == DLM_MLE_MIGRATION);
1272 if (mle->type != DLM_MLE_MASTER) {
1273 request.namelen = mle->u.name.len;
1274 memcpy(request.name, mle->u.name.name, request.namelen);
1276 request.namelen = mle->u.res->lockname.len;
1277 memcpy(request.name, mle->u.res->lockname.name,
1282 ret = o2net_send_message(DLM_MASTER_REQUEST_MSG, dlm->key, &request,
1283 sizeof(request), to, &response);
1285 if (ret == -ESRCH) {
1286 /* should never happen */
1287 mlog(ML_ERROR, "TCP stack not ready!\n");
1289 } else if (ret == -EINVAL) {
1290 mlog(ML_ERROR, "bad args passed to o2net!\n");
1292 } else if (ret == -ENOMEM) {
1293 mlog(ML_ERROR, "out of memory while trying to send "
1294 "network message! retrying\n");
1295 /* this is totally crude */
1298 } else if (!dlm_is_host_down(ret)) {
1299 /* not a network error. bad. */
1301 mlog(ML_ERROR, "unhandled error!");
1304 /* all other errors should be network errors,
1305 * and likely indicate node death */
1306 mlog(ML_ERROR, "link to %d went down!\n", to);
1312 spin_lock(&mle->spinlock);
1314 case DLM_MASTER_RESP_YES:
1315 set_bit(to, mle->response_map);
1316 mlog(0, "node %u is the master, response=YES\n", to);
1319 case DLM_MASTER_RESP_NO:
1320 mlog(0, "node %u not master, response=NO\n", to);
1321 set_bit(to, mle->response_map);
1323 case DLM_MASTER_RESP_MAYBE:
1324 mlog(0, "node %u not master, response=MAYBE\n", to);
1325 set_bit(to, mle->response_map);
1326 set_bit(to, mle->maybe_map);
1328 case DLM_MASTER_RESP_ERROR:
1329 mlog(0, "node %u hit an error, resending\n", to);
1334 mlog(ML_ERROR, "bad response! %u\n", response);
1337 spin_unlock(&mle->spinlock);
1339 /* this is also totally crude */
1349 * locks that can be taken here:
1355 * if possible, TRIM THIS DOWN!!!
1357 int dlm_master_request_handler(struct o2net_msg *msg, u32 len, void *data)
1359 u8 response = DLM_MASTER_RESP_MAYBE;
1360 struct dlm_ctxt *dlm = data;
1361 struct dlm_lock_resource *res = NULL;
1362 struct dlm_master_request *request = (struct dlm_master_request *) msg->buf;
1363 struct dlm_master_list_entry *mle = NULL, *tmpmle = NULL;
1365 unsigned int namelen, hash;
1368 int dispatch_assert = 0;
1371 return DLM_MASTER_RESP_NO;
1373 if (!dlm_domain_fully_joined(dlm)) {
1374 response = DLM_MASTER_RESP_NO;
1378 name = request->name;
1379 namelen = request->namelen;
1380 hash = dlm_lockid_hash(name, namelen);
1382 if (namelen > DLM_LOCKID_NAME_MAX) {
1383 response = DLM_IVBUFLEN;
1388 spin_lock(&dlm->spinlock);
1389 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
1391 spin_unlock(&dlm->spinlock);
1393 /* take care of the easy cases up front */
1394 spin_lock(&res->spinlock);
1395 if (res->state & DLM_LOCK_RES_RECOVERING) {
1396 spin_unlock(&res->spinlock);
1397 mlog(0, "returning DLM_MASTER_RESP_ERROR since res is "
1398 "being recovered\n");
1399 response = DLM_MASTER_RESP_ERROR;
1401 kmem_cache_free(dlm_mle_cache, mle);
1405 if (res->owner == dlm->node_num) {
1406 spin_unlock(&res->spinlock);
1407 // mlog(0, "this node is the master\n");
1408 response = DLM_MASTER_RESP_YES;
1410 kmem_cache_free(dlm_mle_cache, mle);
1412 /* this node is the owner.
1413 * there is some extra work that needs to
1414 * happen now. the requesting node has
1415 * caused all nodes up to this one to
1416 * create mles. this node now needs to
1417 * go back and clean those up. */
1418 dispatch_assert = 1;
1420 } else if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1421 spin_unlock(&res->spinlock);
1422 // mlog(0, "node %u is the master\n", res->owner);
1423 response = DLM_MASTER_RESP_NO;
1425 kmem_cache_free(dlm_mle_cache, mle);
1429 /* ok, there is no owner. either this node is
1430 * being blocked, or it is actively trying to
1431 * master this lock. */
1432 if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
1433 mlog(ML_ERROR, "lock with no owner should be "
1438 // mlog(0, "lockres is in progress...\n");
1439 spin_lock(&dlm->master_lock);
1440 found = dlm_find_mle(dlm, &tmpmle, name, namelen);
1442 mlog(ML_ERROR, "no mle found for this lock!\n");
1446 spin_lock(&tmpmle->spinlock);
1447 if (tmpmle->type == DLM_MLE_BLOCK) {
1448 // mlog(0, "this node is waiting for "
1449 // "lockres to be mastered\n");
1450 response = DLM_MASTER_RESP_NO;
1451 } else if (tmpmle->type == DLM_MLE_MIGRATION) {
1452 mlog(0, "node %u is master, but trying to migrate to "
1453 "node %u.\n", tmpmle->master, tmpmle->new_master);
1454 if (tmpmle->master == dlm->node_num) {
1455 response = DLM_MASTER_RESP_YES;
1456 mlog(ML_ERROR, "no owner on lockres, but this "
1457 "node is trying to migrate it to %u?!\n",
1458 tmpmle->new_master);
1461 /* the real master can respond on its own */
1462 response = DLM_MASTER_RESP_NO;
1464 } else if (tmpmle->master != DLM_LOCK_RES_OWNER_UNKNOWN) {
1466 if (tmpmle->master == dlm->node_num) {
1467 response = DLM_MASTER_RESP_YES;
1468 /* this node will be the owner.
1469 * go back and clean the mles on any
1471 dispatch_assert = 1;
1473 response = DLM_MASTER_RESP_NO;
1475 // mlog(0, "this node is attempting to "
1476 // "master lockres\n");
1477 response = DLM_MASTER_RESP_MAYBE;
1480 set_bit(request->node_idx, tmpmle->maybe_map);
1481 spin_unlock(&tmpmle->spinlock);
1483 spin_unlock(&dlm->master_lock);
1484 spin_unlock(&res->spinlock);
1486 /* keep the mle attached to heartbeat events */
1487 dlm_put_mle(tmpmle);
1489 kmem_cache_free(dlm_mle_cache, mle);
1494 * lockres doesn't exist on this node
1495 * if there is an MLE_BLOCK, return NO
1496 * if there is an MLE_MASTER, return MAYBE
1497 * otherwise, add an MLE_BLOCK, return NO
1499 spin_lock(&dlm->master_lock);
1500 found = dlm_find_mle(dlm, &tmpmle, name, namelen);
1502 /* this lockid has never been seen on this node yet */
1503 // mlog(0, "no mle found\n");
1505 spin_unlock(&dlm->master_lock);
1506 spin_unlock(&dlm->spinlock);
1508 mle = (struct dlm_master_list_entry *)
1509 kmem_cache_alloc(dlm_mle_cache, GFP_KERNEL);
1511 response = DLM_MASTER_RESP_ERROR;
1512 mlog_errno(-ENOMEM);
1518 // mlog(0, "this is second time thru, already allocated, "
1519 // "add the block.\n");
1520 dlm_init_mle(mle, DLM_MLE_BLOCK, dlm, NULL, name, namelen);
1521 set_bit(request->node_idx, mle->maybe_map);
1522 list_add(&mle->list, &dlm->master_list);
1523 response = DLM_MASTER_RESP_NO;
1525 // mlog(0, "mle was found\n");
1527 spin_lock(&tmpmle->spinlock);
1528 if (tmpmle->master == dlm->node_num) {
1529 mlog(ML_ERROR, "no lockres, but an mle with this node as master!\n");
1532 if (tmpmle->type == DLM_MLE_BLOCK)
1533 response = DLM_MASTER_RESP_NO;
1534 else if (tmpmle->type == DLM_MLE_MIGRATION) {
1535 mlog(0, "migration mle was found (%u->%u)\n",
1536 tmpmle->master, tmpmle->new_master);
1537 /* real master can respond on its own */
1538 response = DLM_MASTER_RESP_NO;
1540 response = DLM_MASTER_RESP_MAYBE;
1542 set_bit(request->node_idx, tmpmle->maybe_map);
1543 spin_unlock(&tmpmle->spinlock);
1545 spin_unlock(&dlm->master_lock);
1546 spin_unlock(&dlm->spinlock);
1549 /* keep the mle attached to heartbeat events */
1550 dlm_put_mle(tmpmle);
1554 if (dispatch_assert) {
1555 if (response != DLM_MASTER_RESP_YES)
1556 mlog(ML_ERROR, "invalid response %d\n", response);
1558 mlog(ML_ERROR, "bad lockres while trying to assert!\n");
1561 mlog(0, "%u is the owner of %.*s, cleaning everyone else\n",
1562 dlm->node_num, res->lockname.len, res->lockname.name);
1563 ret = dlm_dispatch_assert_master(dlm, res, 0, request->node_idx,
1564 DLM_ASSERT_MASTER_MLE_CLEANUP);
1566 mlog(ML_ERROR, "failed to dispatch assert master work\n");
1567 response = DLM_MASTER_RESP_ERROR;
1576 * DLM_ASSERT_MASTER_MSG
1581 * NOTE: this can be used for debugging
1582 * can periodically run all locks owned by this node
1583 * and re-assert across the cluster...
1585 static int dlm_do_assert_master(struct dlm_ctxt *dlm, const char *lockname,
1586 unsigned int namelen, void *nodemap,
1589 struct dlm_assert_master assert;
1591 struct dlm_node_iter iter;
1595 BUG_ON(namelen > O2NM_MAX_NAME_LEN);
1599 /* note that if this nodemap is empty, it returns 0 */
1600 dlm_node_iter_init(nodemap, &iter);
1601 while ((to = dlm_node_iter_next(&iter)) >= 0) {
1603 mlog(0, "sending assert master to %d (%.*s)\n", to,
1605 memset(&assert, 0, sizeof(assert));
1606 assert.node_idx = dlm->node_num;
1607 assert.namelen = namelen;
1608 memcpy(assert.name, lockname, namelen);
1609 assert.flags = cpu_to_be32(flags);
1611 tmpret = o2net_send_message(DLM_ASSERT_MASTER_MSG, dlm->key,
1612 &assert, sizeof(assert), to, &r);
1614 mlog(ML_ERROR, "assert_master returned %d!\n", tmpret);
1615 if (!dlm_is_host_down(tmpret)) {
1616 mlog(ML_ERROR, "unhandled error!\n");
1619 /* a node died. finish out the rest of the nodes. */
1620 mlog(ML_ERROR, "link to %d went down!\n", to);
1621 /* any nonzero status return will do */
1624 /* ok, something horribly messed. kill thyself. */
1625 mlog(ML_ERROR,"during assert master of %.*s to %u, "
1626 "got %d.\n", namelen, lockname, to, r);
1627 dlm_dump_lock_resources(dlm);
1629 } else if (r == EAGAIN) {
1630 mlog(0, "%.*s: node %u create mles on other "
1631 "nodes and requests a re-assert\n",
1632 namelen, lockname, to);
1644 * locks that can be taken here:
1650 * if possible, TRIM THIS DOWN!!!
1652 int dlm_assert_master_handler(struct o2net_msg *msg, u32 len, void *data)
1654 struct dlm_ctxt *dlm = data;
1655 struct dlm_master_list_entry *mle = NULL;
1656 struct dlm_assert_master *assert = (struct dlm_assert_master *)msg->buf;
1657 struct dlm_lock_resource *res = NULL;
1659 unsigned int namelen, hash;
1661 int master_request = 0;
1667 name = assert->name;
1668 namelen = assert->namelen;
1669 hash = dlm_lockid_hash(name, namelen);
1670 flags = be32_to_cpu(assert->flags);
1672 if (namelen > DLM_LOCKID_NAME_MAX) {
1673 mlog(ML_ERROR, "Invalid name length!");
1677 spin_lock(&dlm->spinlock);
1680 mlog(0, "assert_master with flags: %u\n", flags);
1683 spin_lock(&dlm->master_lock);
1684 if (!dlm_find_mle(dlm, &mle, name, namelen)) {
1685 /* not an error, could be master just re-asserting */
1686 mlog(0, "just got an assert_master from %u, but no "
1687 "MLE for it! (%.*s)\n", assert->node_idx,
1690 int bit = find_next_bit (mle->maybe_map, O2NM_MAX_NODES, 0);
1691 if (bit >= O2NM_MAX_NODES) {
1692 /* not necessarily an error, though less likely.
1693 * could be master just re-asserting. */
1694 mlog(ML_ERROR, "no bits set in the maybe_map, but %u "
1695 "is asserting! (%.*s)\n", assert->node_idx,
1697 } else if (bit != assert->node_idx) {
1698 if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
1699 mlog(0, "master %u was found, %u should "
1700 "back off\n", assert->node_idx, bit);
1702 /* with the fix for bug 569, a higher node
1703 * number winning the mastery will respond
1704 * YES to mastery requests, but this node
1705 * had no way of knowing. let it pass. */
1706 mlog(ML_ERROR, "%u is the lowest node, "
1707 "%u is asserting. (%.*s) %u must "
1708 "have begun after %u won.\n", bit,
1709 assert->node_idx, namelen, name, bit,
1713 if (mle->type == DLM_MLE_MIGRATION) {
1714 if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
1715 mlog(0, "%s:%.*s: got cleanup assert"
1716 " from %u for migration\n",
1717 dlm->name, namelen, name,
1719 } else if (!(flags & DLM_ASSERT_MASTER_FINISH_MIGRATION)) {
1720 mlog(0, "%s:%.*s: got unrelated assert"
1721 " from %u for migration, ignoring\n",
1722 dlm->name, namelen, name,
1725 spin_unlock(&dlm->master_lock);
1726 spin_unlock(&dlm->spinlock);
1731 spin_unlock(&dlm->master_lock);
1733 /* ok everything checks out with the MLE
1734 * now check to see if there is a lockres */
1735 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
1737 spin_lock(&res->spinlock);
1738 if (res->state & DLM_LOCK_RES_RECOVERING) {
1739 mlog(ML_ERROR, "%u asserting but %.*s is "
1740 "RECOVERING!\n", assert->node_idx, namelen, name);
1744 if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN &&
1745 res->owner != assert->node_idx) {
1746 mlog(ML_ERROR, "assert_master from "
1747 "%u, but current owner is "
1749 assert->node_idx, res->owner,
1753 } else if (mle->type != DLM_MLE_MIGRATION) {
1754 if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1755 /* owner is just re-asserting */
1756 if (res->owner == assert->node_idx) {
1757 mlog(0, "owner %u re-asserting on "
1758 "lock %.*s\n", assert->node_idx,
1762 mlog(ML_ERROR, "got assert_master from "
1763 "node %u, but %u is the owner! "
1764 "(%.*s)\n", assert->node_idx,
1765 res->owner, namelen, name);
1768 if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
1769 mlog(ML_ERROR, "got assert from %u, but lock "
1770 "with no owner should be "
1771 "in-progress! (%.*s)\n",
1776 } else /* mle->type == DLM_MLE_MIGRATION */ {
1777 /* should only be getting an assert from new master */
1778 if (assert->node_idx != mle->new_master) {
1779 mlog(ML_ERROR, "got assert from %u, but "
1780 "new master is %u, and old master "
1782 assert->node_idx, mle->new_master,
1783 mle->master, namelen, name);
1789 spin_unlock(&res->spinlock);
1791 spin_unlock(&dlm->spinlock);
1793 // mlog(0, "woo! got an assert_master from node %u!\n",
1794 // assert->node_idx);
1800 spin_lock(&mle->spinlock);
1801 if (mle->type == DLM_MLE_BLOCK || mle->type == DLM_MLE_MIGRATION)
1804 /* MASTER mle: if any bits set in the response map
1805 * then the calling node needs to re-assert to clear
1806 * up nodes that this node contacted */
1807 while ((nn = find_next_bit (mle->response_map, O2NM_MAX_NODES,
1808 nn+1)) < O2NM_MAX_NODES) {
1809 if (nn != dlm->node_num && nn != assert->node_idx)
1813 mle->master = assert->node_idx;
1814 atomic_set(&mle->woken, 1);
1816 spin_unlock(&mle->spinlock);
1819 spin_lock(&res->spinlock);
1820 if (mle->type == DLM_MLE_MIGRATION) {
1821 mlog(0, "finishing off migration of lockres %.*s, "
1823 res->lockname.len, res->lockname.name,
1824 dlm->node_num, mle->new_master);
1825 res->state &= ~DLM_LOCK_RES_MIGRATING;
1826 dlm_change_lockres_owner(dlm, res, mle->new_master);
1827 BUG_ON(res->state & DLM_LOCK_RES_DIRTY);
1829 dlm_change_lockres_owner(dlm, res, mle->master);
1831 spin_unlock(&res->spinlock);
1834 /* master is known, detach if not already detached.
1835 * ensures that only one assert_master call will happen
1837 spin_lock(&dlm->spinlock);
1838 spin_lock(&dlm->master_lock);
1840 rr = atomic_read(&mle->mle_refs.refcount);
1841 if (mle->inuse > 0) {
1842 if (extra_ref && rr < 3)
1844 else if (!extra_ref && rr < 2)
1847 if (extra_ref && rr < 2)
1849 else if (!extra_ref && rr < 1)
1853 mlog(ML_ERROR, "%s:%.*s: got assert master from %u "
1854 "that will mess up this node, refs=%d, extra=%d, "
1855 "inuse=%d\n", dlm->name, namelen, name,
1856 assert->node_idx, rr, extra_ref, mle->inuse);
1857 dlm_print_one_mle(mle);
1859 list_del_init(&mle->list);
1860 __dlm_mle_detach_hb_events(dlm, mle);
1863 /* the assert master message now balances the extra
1864 * ref given by the master / migration request message.
1865 * if this is the last put, it will be removed
1869 spin_unlock(&dlm->master_lock);
1870 spin_unlock(&dlm->spinlock);
1872 if (res->owner != assert->node_idx) {
1873 mlog(0, "assert_master from %u, but current "
1874 "owner is %u (%.*s), no mle\n", assert->node_idx,
1875 res->owner, namelen, name);
1882 dlm_lockres_put(res);
1884 if (master_request) {
1885 mlog(0, "need to tell master to reassert\n");
1886 ret = EAGAIN; // positive. negative would shoot down the node.
1891 /* kill the caller! */
1892 spin_unlock(&res->spinlock);
1893 spin_unlock(&dlm->spinlock);
1894 dlm_lockres_put(res);
1895 mlog(ML_ERROR, "Bad message received from another node. Dumping state "
1896 "and killing the other node now! This node is OK and can continue.\n");
1897 dlm_dump_lock_resources(dlm);
1902 int dlm_dispatch_assert_master(struct dlm_ctxt *dlm,
1903 struct dlm_lock_resource *res,
1904 int ignore_higher, u8 request_from, u32 flags)
1906 struct dlm_work_item *item;
1907 item = kcalloc(1, sizeof(*item), GFP_KERNEL);
1912 /* queue up work for dlm_assert_master_worker */
1913 dlm_grab(dlm); /* get an extra ref for the work item */
1914 dlm_init_work_item(dlm, item, dlm_assert_master_worker, NULL);
1915 item->u.am.lockres = res; /* already have a ref */
1916 /* can optionally ignore node numbers higher than this node */
1917 item->u.am.ignore_higher = ignore_higher;
1918 item->u.am.request_from = request_from;
1919 item->u.am.flags = flags;
1922 mlog(0, "IGNORE HIGHER: %.*s\n", res->lockname.len,
1923 res->lockname.name);
1925 spin_lock(&dlm->work_lock);
1926 list_add_tail(&item->list, &dlm->work_list);
1927 spin_unlock(&dlm->work_lock);
1929 schedule_work(&dlm->dispatched_work);
1933 static void dlm_assert_master_worker(struct dlm_work_item *item, void *data)
1935 struct dlm_ctxt *dlm = data;
1937 struct dlm_lock_resource *res;
1938 unsigned long nodemap[BITS_TO_LONGS(O2NM_MAX_NODES)];
1945 res = item->u.am.lockres;
1946 ignore_higher = item->u.am.ignore_higher;
1947 request_from = item->u.am.request_from;
1948 flags = item->u.am.flags;
1950 spin_lock(&dlm->spinlock);
1951 memcpy(nodemap, dlm->domain_map, sizeof(nodemap));
1952 spin_unlock(&dlm->spinlock);
1954 clear_bit(dlm->node_num, nodemap);
1955 if (ignore_higher) {
1956 /* if is this just to clear up mles for nodes below
1957 * this node, do not send the message to the original
1958 * caller or any node number higher than this */
1959 clear_bit(request_from, nodemap);
1960 bit = dlm->node_num;
1962 bit = find_next_bit(nodemap, O2NM_MAX_NODES,
1964 if (bit >= O2NM_MAX_NODES)
1966 clear_bit(bit, nodemap);
1970 /* this call now finishes out the nodemap
1971 * even if one or more nodes die */
1972 mlog(0, "worker about to master %.*s here, this=%u\n",
1973 res->lockname.len, res->lockname.name, dlm->node_num);
1974 ret = dlm_do_assert_master(dlm, res->lockname.name,
1978 /* no need to restart, we are done */
1982 dlm_lockres_put(res);
1984 mlog(0, "finished with dlm_assert_master_worker\n");
1987 /* SPECIAL CASE for the $RECOVERY lock used by the recovery thread.
1988 * We cannot wait for node recovery to complete to begin mastering this
1989 * lockres because this lockres is used to kick off recovery! ;-)
1990 * So, do a pre-check on all living nodes to see if any of those nodes
1991 * think that $RECOVERY is currently mastered by a dead node. If so,
1992 * we wait a short time to allow that node to get notified by its own
1993 * heartbeat stack, then check again. All $RECOVERY lock resources
1994 * mastered by dead nodes are purged when the hearbeat callback is
1995 * fired, so we can know for sure that it is safe to continue once
1996 * the node returns a live node or no node. */
1997 static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
1998 struct dlm_lock_resource *res)
2000 struct dlm_node_iter iter;
2003 u8 master = DLM_LOCK_RES_OWNER_UNKNOWN;
2005 spin_lock(&dlm->spinlock);
2006 dlm_node_iter_init(dlm->domain_map, &iter);
2007 spin_unlock(&dlm->spinlock);
2009 while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
2010 /* do not send to self */
2011 if (nodenum == dlm->node_num)
2013 ret = dlm_do_master_requery(dlm, res, nodenum, &master);
2016 if (!dlm_is_host_down(ret))
2018 /* host is down, so answer for that node would be
2019 * DLM_LOCK_RES_OWNER_UNKNOWN. continue. */
2022 if (master != DLM_LOCK_RES_OWNER_UNKNOWN) {
2023 /* check to see if this master is in the recovery map */
2024 spin_lock(&dlm->spinlock);
2025 if (test_bit(master, dlm->recovery_map)) {
2026 mlog(ML_NOTICE, "%s: node %u has not seen "
2027 "node %u go down yet, and thinks the "
2028 "dead node is mastering the recovery "
2029 "lock. must wait.\n", dlm->name,
2033 spin_unlock(&dlm->spinlock);
2034 mlog(0, "%s: reco lock master is %u\n", dlm->name,
2044 * DLM_MIGRATE_LOCKRES
2048 int dlm_migrate_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
2051 struct dlm_master_list_entry *mle = NULL;
2052 struct dlm_master_list_entry *oldmle = NULL;
2053 struct dlm_migratable_lockres *mres = NULL;
2056 unsigned int namelen;
2058 struct list_head *queue, *iter;
2060 struct dlm_lock *lock;
2066 name = res->lockname.name;
2067 namelen = res->lockname.len;
2069 mlog(0, "migrating %.*s to %u\n", namelen, name, target);
2072 * ensure this lockres is a proper candidate for migration
2074 spin_lock(&res->spinlock);
2075 if (res->owner == DLM_LOCK_RES_OWNER_UNKNOWN) {
2076 mlog(0, "cannot migrate lockres with unknown owner!\n");
2077 spin_unlock(&res->spinlock);
2080 if (res->owner != dlm->node_num) {
2081 mlog(0, "cannot migrate lockres this node doesn't own!\n");
2082 spin_unlock(&res->spinlock);
2085 mlog(0, "checking queues...\n");
2086 queue = &res->granted;
2087 for (i=0; i<3; i++) {
2088 list_for_each(iter, queue) {
2089 lock = list_entry (iter, struct dlm_lock, list);
2091 if (lock->ml.node == dlm->node_num) {
2092 mlog(0, "found a lock owned by this node "
2093 "still on the %s queue! will not "
2094 "migrate this lockres\n",
2096 (i==1 ? "converting" : "blocked"));
2097 spin_unlock(&res->spinlock);
2104 mlog(0, "all locks on this lockres are nonlocal. continuing\n");
2105 spin_unlock(&res->spinlock);
2109 mlog(0, "no locks were found on this lockres! done!\n");
2115 * preallocate up front
2116 * if this fails, abort
2120 mres = (struct dlm_migratable_lockres *) __get_free_page(GFP_KERNEL);
2126 mle = (struct dlm_master_list_entry *) kmem_cache_alloc(dlm_mle_cache,
2135 * find a node to migrate the lockres to
2138 mlog(0, "picking a migration node\n");
2139 spin_lock(&dlm->spinlock);
2140 /* pick a new node */
2141 if (!test_bit(target, dlm->domain_map) ||
2142 target >= O2NM_MAX_NODES) {
2143 target = dlm_pick_migration_target(dlm, res);
2145 mlog(0, "node %u chosen for migration\n", target);
2147 if (target >= O2NM_MAX_NODES ||
2148 !test_bit(target, dlm->domain_map)) {
2149 /* target chosen is not alive */
2154 spin_unlock(&dlm->spinlock);
2158 mlog(0, "continuing with target = %u\n", target);
2161 * clear any existing master requests and
2162 * add the migration mle to the list
2164 spin_lock(&dlm->master_lock);
2165 ret = dlm_add_migration_mle(dlm, res, mle, &oldmle, name,
2166 namelen, target, dlm->node_num);
2167 spin_unlock(&dlm->master_lock);
2168 spin_unlock(&dlm->spinlock);
2170 if (ret == -EEXIST) {
2171 mlog(0, "another process is already migrating it\n");
2177 * set the MIGRATING flag and flush asts
2178 * if we fail after this we need to re-dirty the lockres
2180 if (dlm_mark_lockres_migrating(dlm, res, target) < 0) {
2181 mlog(ML_ERROR, "tried to migrate %.*s to %u, but "
2182 "the target went down.\n", res->lockname.len,
2183 res->lockname.name, target);
2184 spin_lock(&res->spinlock);
2185 res->state &= ~DLM_LOCK_RES_MIGRATING;
2186 spin_unlock(&res->spinlock);
2192 /* master is known, detach if not already detached */
2193 dlm_mle_detach_hb_events(dlm, oldmle);
2194 dlm_put_mle(oldmle);
2199 dlm_mle_detach_hb_events(dlm, mle);
2202 kmem_cache_free(dlm_mle_cache, mle);
2208 * at this point, we have a migration target, an mle
2209 * in the master list, and the MIGRATING flag set on
2214 /* get an extra reference on the mle.
2215 * otherwise the assert_master from the new
2216 * master will destroy this.
2217 * also, make sure that all callers of dlm_get_mle
2218 * take both dlm->spinlock and dlm->master_lock */
2219 spin_lock(&dlm->spinlock);
2220 spin_lock(&dlm->master_lock);
2221 dlm_get_mle_inuse(mle);
2222 spin_unlock(&dlm->master_lock);
2223 spin_unlock(&dlm->spinlock);
2225 /* notify new node and send all lock state */
2226 /* call send_one_lockres with migration flag.
2227 * this serves as notice to the target node that a
2228 * migration is starting. */
2229 ret = dlm_send_one_lockres(dlm, res, mres, target,
2230 DLM_MRES_MIGRATION);
2233 mlog(0, "migration to node %u failed with %d\n",
2235 /* migration failed, detach and clean up mle */
2236 dlm_mle_detach_hb_events(dlm, mle);
2238 dlm_put_mle_inuse(mle);
2239 spin_lock(&res->spinlock);
2240 res->state &= ~DLM_LOCK_RES_MIGRATING;
2241 spin_unlock(&res->spinlock);
2245 /* at this point, the target sends a message to all nodes,
2246 * (using dlm_do_migrate_request). this node is skipped since
2247 * we had to put an mle in the list to begin the process. this
2248 * node now waits for target to do an assert master. this node
2249 * will be the last one notified, ensuring that the migration
2250 * is complete everywhere. if the target dies while this is
2251 * going on, some nodes could potentially see the target as the
2252 * master, so it is important that my recovery finds the migration
2253 * mle and sets the master to UNKNONWN. */
2256 /* wait for new node to assert master */
2258 ret = wait_event_interruptible_timeout(mle->wq,
2259 (atomic_read(&mle->woken) == 1),
2260 msecs_to_jiffies(5000));
2263 if (atomic_read(&mle->woken) == 1 ||
2264 res->owner == target)
2267 mlog(0, "timed out during migration\n");
2268 /* avoid hang during shutdown when migrating lockres
2269 * to a node which also goes down */
2270 if (dlm_is_node_dead(dlm, target)) {
2271 mlog(0, "%s:%.*s: expected migration target %u "
2272 "is no longer up. restarting.\n",
2273 dlm->name, res->lockname.len,
2274 res->lockname.name, target);
2278 if (ret == -ERESTARTSYS) {
2279 /* migration failed, detach and clean up mle */
2280 dlm_mle_detach_hb_events(dlm, mle);
2282 dlm_put_mle_inuse(mle);
2283 spin_lock(&res->spinlock);
2284 res->state &= ~DLM_LOCK_RES_MIGRATING;
2285 spin_unlock(&res->spinlock);
2288 /* TODO: if node died: stop, clean up, return error */
2291 /* all done, set the owner, clear the flag */
2292 spin_lock(&res->spinlock);
2293 dlm_set_lockres_owner(dlm, res, target);
2294 res->state &= ~DLM_LOCK_RES_MIGRATING;
2295 dlm_remove_nonlocal_locks(dlm, res);
2296 spin_unlock(&res->spinlock);
2299 /* master is known, detach if not already detached */
2300 dlm_mle_detach_hb_events(dlm, mle);
2301 dlm_put_mle_inuse(mle);
2304 dlm_lockres_calc_usage(dlm, res);
2307 /* re-dirty the lockres if we failed */
2309 dlm_kick_thread(dlm, res);
2313 free_page((unsigned long)mres);
2317 mlog(0, "returning %d\n", ret);
2320 EXPORT_SYMBOL_GPL(dlm_migrate_lockres);
2322 int dlm_lock_basts_flushed(struct dlm_ctxt *dlm, struct dlm_lock *lock)
2325 spin_lock(&dlm->ast_lock);
2326 spin_lock(&lock->spinlock);
2327 ret = (list_empty(&lock->bast_list) && !lock->bast_pending);
2328 spin_unlock(&lock->spinlock);
2329 spin_unlock(&dlm->ast_lock);
2333 static int dlm_migration_can_proceed(struct dlm_ctxt *dlm,
2334 struct dlm_lock_resource *res,
2338 spin_lock(&res->spinlock);
2339 can_proceed = !!(res->state & DLM_LOCK_RES_MIGRATING);
2340 spin_unlock(&res->spinlock);
2342 /* target has died, so make the caller break out of the
2343 * wait_event, but caller must recheck the domain_map */
2344 spin_lock(&dlm->spinlock);
2345 if (!test_bit(mig_target, dlm->domain_map))
2347 spin_unlock(&dlm->spinlock);
2351 int dlm_lockres_is_dirty(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
2354 spin_lock(&res->spinlock);
2355 ret = !!(res->state & DLM_LOCK_RES_DIRTY);
2356 spin_unlock(&res->spinlock);
2361 static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
2362 struct dlm_lock_resource *res,
2367 mlog(0, "dlm_mark_lockres_migrating: %.*s, from %u to %u\n",
2368 res->lockname.len, res->lockname.name, dlm->node_num,
2370 /* need to set MIGRATING flag on lockres. this is done by
2371 * ensuring that all asts have been flushed for this lockres. */
2372 spin_lock(&res->spinlock);
2373 BUG_ON(res->migration_pending);
2374 res->migration_pending = 1;
2375 /* strategy is to reserve an extra ast then release
2376 * it below, letting the release do all of the work */
2377 __dlm_lockres_reserve_ast(res);
2378 spin_unlock(&res->spinlock);
2380 /* now flush all the pending asts.. hang out for a bit */
2381 dlm_kick_thread(dlm, res);
2382 wait_event(dlm->ast_wq, !dlm_lockres_is_dirty(dlm, res));
2383 dlm_lockres_release_ast(dlm, res);
2385 mlog(0, "about to wait on migration_wq, dirty=%s\n",
2386 res->state & DLM_LOCK_RES_DIRTY ? "yes" : "no");
2387 /* if the extra ref we just put was the final one, this
2388 * will pass thru immediately. otherwise, we need to wait
2389 * for the last ast to finish. */
2391 ret = wait_event_interruptible_timeout(dlm->migration_wq,
2392 dlm_migration_can_proceed(dlm, res, target),
2393 msecs_to_jiffies(1000));
2395 mlog(0, "woken again: migrating? %s, dead? %s\n",
2396 res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
2397 test_bit(target, dlm->domain_map) ? "no":"yes");
2399 mlog(0, "all is well: migrating? %s, dead? %s\n",
2400 res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
2401 test_bit(target, dlm->domain_map) ? "no":"yes");
2403 if (!dlm_migration_can_proceed(dlm, res, target)) {
2404 mlog(0, "trying again...\n");
2408 /* did the target go down or die? */
2409 spin_lock(&dlm->spinlock);
2410 if (!test_bit(target, dlm->domain_map)) {
2411 mlog(ML_ERROR, "aha. migration target %u just went down\n",
2415 spin_unlock(&dlm->spinlock);
2420 * o the DLM_LOCK_RES_MIGRATING flag is set
2421 * o there are no pending asts on this lockres
2422 * o all processes trying to reserve an ast on this
2423 * lockres must wait for the MIGRATING flag to clear
2428 /* last step in the migration process.
2429 * original master calls this to free all of the dlm_lock
2430 * structures that used to be for other nodes. */
2431 static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
2432 struct dlm_lock_resource *res)
2434 struct list_head *iter, *iter2;
2435 struct list_head *queue = &res->granted;
2437 struct dlm_lock *lock;
2439 assert_spin_locked(&res->spinlock);
2441 BUG_ON(res->owner == dlm->node_num);
2443 for (i=0; i<3; i++) {
2444 list_for_each_safe(iter, iter2, queue) {
2445 lock = list_entry (iter, struct dlm_lock, list);
2446 if (lock->ml.node != dlm->node_num) {
2447 mlog(0, "putting lock for node %u\n",
2449 /* be extra careful */
2450 BUG_ON(!list_empty(&lock->ast_list));
2451 BUG_ON(!list_empty(&lock->bast_list));
2452 BUG_ON(lock->ast_pending);
2453 BUG_ON(lock->bast_pending);
2454 list_del_init(&lock->list);
2462 /* for now this is not too intelligent. we will
2463 * need stats to make this do the right thing.
2464 * this just finds the first lock on one of the
2465 * queues and uses that node as the target. */
2466 static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
2467 struct dlm_lock_resource *res)
2470 struct list_head *queue = &res->granted;
2471 struct list_head *iter;
2472 struct dlm_lock *lock;
2475 assert_spin_locked(&dlm->spinlock);
2477 spin_lock(&res->spinlock);
2478 for (i=0; i<3; i++) {
2479 list_for_each(iter, queue) {
2480 /* up to the caller to make sure this node
2482 lock = list_entry (iter, struct dlm_lock, list);
2483 if (lock->ml.node != dlm->node_num) {
2484 spin_unlock(&res->spinlock);
2485 return lock->ml.node;
2490 spin_unlock(&res->spinlock);
2491 mlog(0, "have not found a suitable target yet! checking domain map\n");
2493 /* ok now we're getting desperate. pick anyone alive. */
2496 nodenum = find_next_bit(dlm->domain_map,
2497 O2NM_MAX_NODES, nodenum+1);
2498 mlog(0, "found %d in domain map\n", nodenum);
2499 if (nodenum >= O2NM_MAX_NODES)
2501 if (nodenum != dlm->node_num) {
2502 mlog(0, "picking %d\n", nodenum);
2507 mlog(0, "giving up. no master to migrate to\n");
2508 return DLM_LOCK_RES_OWNER_UNKNOWN;
2513 /* this is called by the new master once all lockres
2514 * data has been received */
2515 static int dlm_do_migrate_request(struct dlm_ctxt *dlm,
2516 struct dlm_lock_resource *res,
2517 u8 master, u8 new_master,
2518 struct dlm_node_iter *iter)
2520 struct dlm_migrate_request migrate;
2521 int ret, status = 0;
2524 memset(&migrate, 0, sizeof(migrate));
2525 migrate.namelen = res->lockname.len;
2526 memcpy(migrate.name, res->lockname.name, migrate.namelen);
2527 migrate.new_master = new_master;
2528 migrate.master = master;
2532 /* send message to all nodes, except the master and myself */
2533 while ((nodenum = dlm_node_iter_next(iter)) >= 0) {
2534 if (nodenum == master ||
2535 nodenum == new_master)
2538 ret = o2net_send_message(DLM_MIGRATE_REQUEST_MSG, dlm->key,
2539 &migrate, sizeof(migrate), nodenum,
2543 else if (status < 0) {
2544 mlog(0, "migrate request (node %u) returned %d!\n",
2553 mlog(0, "returning ret=%d\n", ret);
2558 /* if there is an existing mle for this lockres, we now know who the master is.
2559 * (the one who sent us *this* message) we can clear it up right away.
2560 * since the process that put the mle on the list still has a reference to it,
2561 * we can unhash it now, set the master and wake the process. as a result,
2562 * we will have no mle in the list to start with. now we can add an mle for
2563 * the migration and this should be the only one found for those scanning the
2565 int dlm_migrate_request_handler(struct o2net_msg *msg, u32 len, void *data)
2567 struct dlm_ctxt *dlm = data;
2568 struct dlm_lock_resource *res = NULL;
2569 struct dlm_migrate_request *migrate = (struct dlm_migrate_request *) msg->buf;
2570 struct dlm_master_list_entry *mle = NULL, *oldmle = NULL;
2572 unsigned int namelen, hash;
2578 name = migrate->name;
2579 namelen = migrate->namelen;
2580 hash = dlm_lockid_hash(name, namelen);
2582 /* preallocate.. if this fails, abort */
2583 mle = (struct dlm_master_list_entry *) kmem_cache_alloc(dlm_mle_cache,
2591 /* check for pre-existing lock */
2592 spin_lock(&dlm->spinlock);
2593 res = __dlm_lookup_lockres(dlm, name, namelen, hash);
2594 spin_lock(&dlm->master_lock);
2597 spin_lock(&res->spinlock);
2598 if (res->state & DLM_LOCK_RES_RECOVERING) {
2599 /* if all is working ok, this can only mean that we got
2600 * a migrate request from a node that we now see as
2601 * dead. what can we do here? drop it to the floor? */
2602 spin_unlock(&res->spinlock);
2603 mlog(ML_ERROR, "Got a migrate request, but the "
2604 "lockres is marked as recovering!");
2605 kmem_cache_free(dlm_mle_cache, mle);
2606 ret = -EINVAL; /* need a better solution */
2609 res->state |= DLM_LOCK_RES_MIGRATING;
2610 spin_unlock(&res->spinlock);
2613 /* ignore status. only nonzero status would BUG. */
2614 ret = dlm_add_migration_mle(dlm, res, mle, &oldmle,
2616 migrate->new_master,
2620 spin_unlock(&dlm->master_lock);
2621 spin_unlock(&dlm->spinlock);
2624 /* master is known, detach if not already detached */
2625 dlm_mle_detach_hb_events(dlm, oldmle);
2626 dlm_put_mle(oldmle);
2630 dlm_lockres_put(res);
2636 /* must be holding dlm->spinlock and dlm->master_lock
2637 * when adding a migration mle, we can clear any other mles
2638 * in the master list because we know with certainty that
2639 * the master is "master". so we remove any old mle from
2640 * the list after setting it's master field, and then add
2641 * the new migration mle. this way we can hold with the rule
2642 * of having only one mle for a given lock name at all times. */
2643 static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
2644 struct dlm_lock_resource *res,
2645 struct dlm_master_list_entry *mle,
2646 struct dlm_master_list_entry **oldmle,
2647 const char *name, unsigned int namelen,
2648 u8 new_master, u8 master)
2657 assert_spin_locked(&dlm->spinlock);
2658 assert_spin_locked(&dlm->master_lock);
2660 /* caller is responsible for any ref taken here on oldmle */
2661 found = dlm_find_mle(dlm, oldmle, (char *)name, namelen);
2663 struct dlm_master_list_entry *tmp = *oldmle;
2664 spin_lock(&tmp->spinlock);
2665 if (tmp->type == DLM_MLE_MIGRATION) {
2666 if (master == dlm->node_num) {
2667 /* ah another process raced me to it */
2668 mlog(0, "tried to migrate %.*s, but some "
2669 "process beat me to it\n",
2673 /* bad. 2 NODES are trying to migrate! */
2674 mlog(ML_ERROR, "migration error mle: "
2675 "master=%u new_master=%u // request: "
2676 "master=%u new_master=%u // "
2678 tmp->master, tmp->new_master,
2684 /* this is essentially what assert_master does */
2685 tmp->master = master;
2686 atomic_set(&tmp->woken, 1);
2688 /* remove it from the list so that only one
2689 * mle will be found */
2690 list_del_init(&tmp->list);
2691 __dlm_mle_detach_hb_events(dlm, mle);
2693 spin_unlock(&tmp->spinlock);
2696 /* now add a migration mle to the tail of the list */
2697 dlm_init_mle(mle, DLM_MLE_MIGRATION, dlm, res, name, namelen);
2698 mle->new_master = new_master;
2699 mle->master = master;
2700 /* do this for consistency with other mle types */
2701 set_bit(new_master, mle->maybe_map);
2702 list_add(&mle->list, &dlm->master_list);
2708 void dlm_clean_master_list(struct dlm_ctxt *dlm, u8 dead_node)
2710 struct list_head *iter, *iter2;
2711 struct dlm_master_list_entry *mle;
2712 struct dlm_lock_resource *res;
2715 mlog_entry("dlm=%s, dead node=%u\n", dlm->name, dead_node);
2717 assert_spin_locked(&dlm->spinlock);
2719 /* clean the master list */
2720 spin_lock(&dlm->master_lock);
2721 list_for_each_safe(iter, iter2, &dlm->master_list) {
2722 mle = list_entry(iter, struct dlm_master_list_entry, list);
2724 BUG_ON(mle->type != DLM_MLE_BLOCK &&
2725 mle->type != DLM_MLE_MASTER &&
2726 mle->type != DLM_MLE_MIGRATION);
2728 /* MASTER mles are initiated locally. the waiting
2729 * process will notice the node map change
2730 * shortly. let that happen as normal. */
2731 if (mle->type == DLM_MLE_MASTER)
2735 /* BLOCK mles are initiated by other nodes.
2736 * need to clean up if the dead node would have
2737 * been the master. */
2738 if (mle->type == DLM_MLE_BLOCK) {
2741 spin_lock(&mle->spinlock);
2742 bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
2743 if (bit != dead_node) {
2744 mlog(0, "mle found, but dead node %u would "
2745 "not have been master\n", dead_node);
2746 spin_unlock(&mle->spinlock);
2748 /* must drop the refcount by one since the
2749 * assert_master will never arrive. this
2750 * may result in the mle being unlinked and
2751 * freed, but there may still be a process
2752 * waiting in the dlmlock path which is fine. */
2753 mlog(ML_ERROR, "node %u was expected master\n",
2755 atomic_set(&mle->woken, 1);
2756 spin_unlock(&mle->spinlock);
2758 /* do not need events any longer, so detach
2760 __dlm_mle_detach_hb_events(dlm, mle);
2766 /* everything else is a MIGRATION mle */
2768 /* the rule for MIGRATION mles is that the master
2769 * becomes UNKNOWN if *either* the original or
2770 * the new master dies. all UNKNOWN lockreses
2771 * are sent to whichever node becomes the recovery
2772 * master. the new master is responsible for
2773 * determining if there is still a master for
2774 * this lockres, or if he needs to take over
2775 * mastery. either way, this node should expect
2776 * another message to resolve this. */
2777 if (mle->master != dead_node &&
2778 mle->new_master != dead_node)
2781 /* if we have reached this point, this mle needs to
2782 * be removed from the list and freed. */
2784 /* remove from the list early. NOTE: unlinking
2785 * list_head while in list_for_each_safe */
2786 __dlm_mle_detach_hb_events(dlm, mle);
2787 spin_lock(&mle->spinlock);
2788 list_del_init(&mle->list);
2789 atomic_set(&mle->woken, 1);
2790 spin_unlock(&mle->spinlock);
2793 mlog(0, "node %u died during migration from "
2794 "%u to %u!\n", dead_node,
2795 mle->master, mle->new_master);
2796 /* if there is a lockres associated with this
2797 * mle, find it and set its owner to UNKNOWN */
2798 hash = dlm_lockid_hash(mle->u.name.name, mle->u.name.len);
2799 res = __dlm_lookup_lockres(dlm, mle->u.name.name,
2800 mle->u.name.len, hash);
2802 /* unfortunately if we hit this rare case, our
2803 * lock ordering is messed. we need to drop
2804 * the master lock so that we can take the
2805 * lockres lock, meaning that we will have to
2806 * restart from the head of list. */
2807 spin_unlock(&dlm->master_lock);
2809 /* move lockres onto recovery list */
2810 spin_lock(&res->spinlock);
2811 dlm_set_lockres_owner(dlm, res,
2812 DLM_LOCK_RES_OWNER_UNKNOWN);
2813 dlm_move_lockres_to_recovery_list(dlm, res);
2814 spin_unlock(&res->spinlock);
2815 dlm_lockres_put(res);
2817 /* about to get rid of mle, detach from heartbeat */
2818 __dlm_mle_detach_hb_events(dlm, mle);
2821 spin_lock(&dlm->master_lock);
2823 spin_unlock(&dlm->master_lock);
2829 /* this may be the last reference */
2832 spin_unlock(&dlm->master_lock);
2836 int dlm_finish_migration(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
2839 struct dlm_node_iter iter;
2842 spin_lock(&dlm->spinlock);
2843 dlm_node_iter_init(dlm->domain_map, &iter);
2844 clear_bit(old_master, iter.node_map);
2845 clear_bit(dlm->node_num, iter.node_map);
2846 spin_unlock(&dlm->spinlock);
2848 mlog(0, "now time to do a migrate request to other nodes\n");
2849 ret = dlm_do_migrate_request(dlm, res, old_master,
2850 dlm->node_num, &iter);
2856 mlog(0, "doing assert master of %.*s to all except the original node\n",
2857 res->lockname.len, res->lockname.name);
2858 /* this call now finishes out the nodemap
2859 * even if one or more nodes die */
2860 ret = dlm_do_assert_master(dlm, res->lockname.name,
2861 res->lockname.len, iter.node_map,
2862 DLM_ASSERT_MASTER_FINISH_MIGRATION);
2864 /* no longer need to retry. all living nodes contacted. */
2869 memset(iter.node_map, 0, sizeof(iter.node_map));
2870 set_bit(old_master, iter.node_map);
2871 mlog(0, "doing assert master of %.*s back to %u\n",
2872 res->lockname.len, res->lockname.name, old_master);
2873 ret = dlm_do_assert_master(dlm, res->lockname.name,
2874 res->lockname.len, iter.node_map,
2875 DLM_ASSERT_MASTER_FINISH_MIGRATION);
2877 mlog(0, "assert master to original master failed "
2879 /* the only nonzero status here would be because of
2880 * a dead original node. we're done. */
2884 /* all done, set the owner, clear the flag */
2885 spin_lock(&res->spinlock);
2886 dlm_set_lockres_owner(dlm, res, dlm->node_num);
2887 res->state &= ~DLM_LOCK_RES_MIGRATING;
2888 spin_unlock(&res->spinlock);
2889 /* re-dirty it on the new master */
2890 dlm_kick_thread(dlm, res);
2897 * LOCKRES AST REFCOUNT
2898 * this is integral to migration
2901 /* for future intent to call an ast, reserve one ahead of time.
2902 * this should be called only after waiting on the lockres
2903 * with dlm_wait_on_lockres, and while still holding the
2904 * spinlock after the call. */
2905 void __dlm_lockres_reserve_ast(struct dlm_lock_resource *res)
2907 assert_spin_locked(&res->spinlock);
2908 if (res->state & DLM_LOCK_RES_MIGRATING) {
2909 __dlm_print_one_lock_resource(res);
2911 BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
2913 atomic_inc(&res->asts_reserved);
2917 * used to drop the reserved ast, either because it went unused,
2918 * or because the ast/bast was actually called.
2920 * also, if there is a pending migration on this lockres,
2921 * and this was the last pending ast on the lockres,
2922 * atomically set the MIGRATING flag before we drop the lock.
2923 * this is how we ensure that migration can proceed with no
2924 * asts in progress. note that it is ok if the state of the
2925 * queues is such that a lock should be granted in the future
2926 * or that a bast should be fired, because the new master will
2927 * shuffle the lists on this lockres as soon as it is migrated.
2929 void dlm_lockres_release_ast(struct dlm_ctxt *dlm,
2930 struct dlm_lock_resource *res)
2932 if (!atomic_dec_and_lock(&res->asts_reserved, &res->spinlock))
2935 if (!res->migration_pending) {
2936 spin_unlock(&res->spinlock);
2940 BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
2941 res->migration_pending = 0;
2942 res->state |= DLM_LOCK_RES_MIGRATING;
2943 spin_unlock(&res->spinlock);
2945 wake_up(&dlm->migration_wq);