1	// SPDX-License-Identifier: GPL-2.0-or-later
2	/*
3	* dlmmod.c
4	*
5	* standalone DLM module
6	*
7	* Copyright (C) 2004 Oracle. All rights reserved.
8	*/
9
10
11	#include <linux/module.h>
12	#include <linux/fs.h>
13	#include <linux/types.h>
14	#include <linux/slab.h>
15	#include <linux/highmem.h>
16	#include <linux/init.h>
17	#include <linux/sysctl.h>
18	#include <linux/random.h>
19	#include <linux/blkdev.h>
20	#include <linux/socket.h>
21	#include <linux/inet.h>
22	#include <linux/spinlock.h>
23	#include <linux/delay.h>
24
25
26	#include "../cluster/heartbeat.h"
27	#include "../cluster/nodemanager.h"
28	#include "../cluster/tcp.h"
29
30	#include "dlmapi.h"
31	#include "dlmcommon.h"
32	#include "dlmdomain.h"
33	#include "dlmdebug.h"
34
35	#define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_MASTER)
36	#include "../cluster/masklog.h"
37
38	static void dlm_mle_node_down(struct dlm_ctxt *dlm,
39	struct dlm_master_list_entry *mle,
40	struct o2nm_node *node,
41	int idx);
42	static void dlm_mle_node_up(struct dlm_ctxt *dlm,
43	struct dlm_master_list_entry *mle,
44	struct o2nm_node *node,
45	int idx);
46
47	static void dlm_assert_master_worker(struct dlm_work_item *item, void *data);
48	static int dlm_do_assert_master(struct dlm_ctxt *dlm,
49	struct dlm_lock_resource *res,
50	void *nodemap, u32 flags);
51	static void dlm_deref_lockres_worker(struct dlm_work_item *item, void *data);
52
53	static inline int dlm_mle_equal(struct dlm_ctxt *dlm,
54	struct dlm_master_list_entry *mle,
55	const char *name,
56	unsigned int namelen)
57	{
58	if (dlm != mle->dlm)
59	return 0;
60
61	if (namelen != mle->mnamelen ||
62	memcmp(p: name, q: mle->mname, size: namelen) != 0)
63	return 0;
64
65	return 1;
66	}
67
68	static struct kmem_cache *dlm_lockres_cache;
69	static struct kmem_cache *dlm_lockname_cache;
70	static struct kmem_cache *dlm_mle_cache;
71
72	static void dlm_mle_release(struct kref *kref);
73	static void dlm_init_mle(struct dlm_master_list_entry *mle,
74	enum dlm_mle_type type,
75	struct dlm_ctxt *dlm,
76	struct dlm_lock_resource *res,
77	const char *name,
78	unsigned int namelen);
79	static void dlm_put_mle(struct dlm_master_list_entry *mle);
80	static void __dlm_put_mle(struct dlm_master_list_entry *mle);
81	static int dlm_find_mle(struct dlm_ctxt *dlm,
82	struct dlm_master_list_entry **mle,
83	char *name, unsigned int namelen);
84
85	static int dlm_do_master_request(struct dlm_lock_resource *res,
86	struct dlm_master_list_entry *mle, int to);
87
88
89	static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
90	struct dlm_lock_resource *res,
91	struct dlm_master_list_entry *mle,
92	int *blocked);
93	static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
94	struct dlm_lock_resource *res,
95	struct dlm_master_list_entry *mle,
96	int blocked);
97	static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
98	struct dlm_lock_resource *res,
99	struct dlm_master_list_entry *mle,
100	struct dlm_master_list_entry **oldmle,
101	const char *name, unsigned int namelen,
102	u8 new_master, u8 master);
103
104	static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
105	struct dlm_lock_resource *res);
106	static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
107	struct dlm_lock_resource *res);
108	static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
109	struct dlm_lock_resource *res,
110	u8 target);
111	static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
112	struct dlm_lock_resource *res);
113
114
115	int dlm_is_host_down(int errno)
116	{
117	switch (errno) {
118	case -EBADF:
119	case -ECONNREFUSED:
120	case -ENOTCONN:
121	case -ECONNRESET:
122	case -EPIPE:
123	case -EHOSTDOWN:
124	case -EHOSTUNREACH:
125	case -ETIMEDOUT:
126	case -ECONNABORTED:
127	case -ENETDOWN:
128	case -ENETUNREACH:
129	case -ENETRESET:
130	case -ESHUTDOWN:
131	case -ENOPROTOOPT:
132	case -EINVAL: /* if returned from our tcp code,
133	this means there is no socket */
134	return 1;
135	}
136	return 0;
137	}
138
139
140	/*
141	* MASTER LIST FUNCTIONS
142	*/
143
144
145	/*
146	* regarding master list entries and heartbeat callbacks:
147	*
148	* in order to avoid sleeping and allocation that occurs in
149	* heartbeat, master list entries are simply attached to the
150	* dlm's established heartbeat callbacks. the mle is attached
151	* when it is created, and since the dlm->spinlock is held at
152	* that time, any heartbeat event will be properly discovered
153	* by the mle. the mle needs to be detached from the
154	* dlm->mle_hb_events list as soon as heartbeat events are no
155	* longer useful to the mle, and before the mle is freed.
156	*
157	* as a general rule, heartbeat events are no longer needed by
158	* the mle once an "answer" regarding the lock master has been
159	* received.
160	*/
161	static inline void __dlm_mle_attach_hb_events(struct dlm_ctxt *dlm,
162	struct dlm_master_list_entry *mle)
163	{
164	assert_spin_locked(&dlm->spinlock);
165
166	list_add_tail(new: &mle->hb_events, head: &dlm->mle_hb_events);
167	}
168
169
170	static inline void __dlm_mle_detach_hb_events(struct dlm_ctxt *dlm,
171	struct dlm_master_list_entry *mle)
172	{
173	if (!list_empty(head: &mle->hb_events))
174	list_del_init(entry: &mle->hb_events);
175	}
176
177
178	static inline void dlm_mle_detach_hb_events(struct dlm_ctxt *dlm,
179	struct dlm_master_list_entry *mle)
180	{
181	spin_lock(lock: &dlm->spinlock);
182	__dlm_mle_detach_hb_events(dlm, mle);
183	spin_unlock(lock: &dlm->spinlock);
184	}
185
186	static void dlm_get_mle_inuse(struct dlm_master_list_entry *mle)
187	{
188	struct dlm_ctxt *dlm;
189	dlm = mle->dlm;
190
191	assert_spin_locked(&dlm->spinlock);
192	assert_spin_locked(&dlm->master_lock);
193	mle->inuse++;
194	kref_get(kref: &mle->mle_refs);
195	}
196
197	static void dlm_put_mle_inuse(struct dlm_master_list_entry *mle)
198	{
199	struct dlm_ctxt *dlm;
200	dlm = mle->dlm;
201
202	spin_lock(lock: &dlm->spinlock);
203	spin_lock(lock: &dlm->master_lock);
204	mle->inuse--;
205	__dlm_put_mle(mle);
206	spin_unlock(lock: &dlm->master_lock);
207	spin_unlock(lock: &dlm->spinlock);
208
209	}
210
211	/* remove from list and free */
212	static void __dlm_put_mle(struct dlm_master_list_entry *mle)
213	{
214	struct dlm_ctxt *dlm;
215	dlm = mle->dlm;
216
217	assert_spin_locked(&dlm->spinlock);
218	assert_spin_locked(&dlm->master_lock);
219	if (!kref_read(kref: &mle->mle_refs)) {
220	/* this may or may not crash, but who cares.
221	* it's a BUG. */
222	mlog(ML_ERROR, "bad mle: %p\n", mle);
223	dlm_print_one_mle(mle);
224	BUG();
225	} else
226	kref_put(kref: &mle->mle_refs, release: dlm_mle_release);
227	}
228
229
230	/* must not have any spinlocks coming in */
231	static void dlm_put_mle(struct dlm_master_list_entry *mle)
232	{
233	struct dlm_ctxt *dlm;
234	dlm = mle->dlm;
235
236	spin_lock(lock: &dlm->spinlock);
237	spin_lock(lock: &dlm->master_lock);
238	__dlm_put_mle(mle);
239	spin_unlock(lock: &dlm->master_lock);
240	spin_unlock(lock: &dlm->spinlock);
241	}
242
243	static inline void dlm_get_mle(struct dlm_master_list_entry *mle)
244	{
245	kref_get(kref: &mle->mle_refs);
246	}
247
248	static void dlm_init_mle(struct dlm_master_list_entry *mle,
249	enum dlm_mle_type type,
250	struct dlm_ctxt *dlm,
251	struct dlm_lock_resource *res,
252	const char *name,
253	unsigned int namelen)
254	{
255	assert_spin_locked(&dlm->spinlock);
256
257	mle->dlm = dlm;
258	mle->type = type;
259	INIT_HLIST_NODE(h: &mle->master_hash_node);
260	INIT_LIST_HEAD(list: &mle->hb_events);
261	bitmap_zero(dst: mle->maybe_map, O2NM_MAX_NODES);
262	spin_lock_init(&mle->spinlock);
263	init_waitqueue_head(&mle->wq);
264	atomic_set(v: &mle->woken, i: 0);
265	kref_init(kref: &mle->mle_refs);
266	bitmap_zero(dst: mle->response_map, O2NM_MAX_NODES);
267	mle->master = O2NM_MAX_NODES;
268	mle->new_master = O2NM_MAX_NODES;
269	mle->inuse = 0;
270
271	BUG_ON(mle->type != DLM_MLE_BLOCK &&
272	mle->type != DLM_MLE_MASTER &&
273	mle->type != DLM_MLE_MIGRATION);
274
275	if (mle->type == DLM_MLE_MASTER) {
276	BUG_ON(!res);
277	mle->mleres = res;
278	memcpy(mle->mname, res->lockname.name, res->lockname.len);
279	mle->mnamelen = res->lockname.len;
280	mle->mnamehash = res->lockname.hash;
281	} else {
282	BUG_ON(!name);
283	mle->mleres = NULL;
284	memcpy(mle->mname, name, namelen);
285	mle->mnamelen = namelen;
286	mle->mnamehash = dlm_lockid_hash(name, namelen);
287	}
288
289	atomic_inc(v: &dlm->mle_tot_count[mle->type]);
290	atomic_inc(v: &dlm->mle_cur_count[mle->type]);
291
292	/* copy off the node_map and register hb callbacks on our copy */
293	bitmap_copy(dst: mle->node_map, src: dlm->domain_map, O2NM_MAX_NODES);
294	bitmap_copy(dst: mle->vote_map, src: dlm->domain_map, O2NM_MAX_NODES);
295	clear_bit(nr: dlm->node_num, addr: mle->vote_map);
296	clear_bit(nr: dlm->node_num, addr: mle->node_map);
297
298	/* attach the mle to the domain node up/down events */
299	__dlm_mle_attach_hb_events(dlm, mle);
300	}
301
302	void __dlm_unlink_mle(struct dlm_ctxt *dlm, struct dlm_master_list_entry *mle)
303	{
304	assert_spin_locked(&dlm->spinlock);
305	assert_spin_locked(&dlm->master_lock);
306
307	if (!hlist_unhashed(h: &mle->master_hash_node))
308	hlist_del_init(n: &mle->master_hash_node);
309	}
310
311	void __dlm_insert_mle(struct dlm_ctxt *dlm, struct dlm_master_list_entry *mle)
312	{
313	struct hlist_head *bucket;
314
315	assert_spin_locked(&dlm->master_lock);
316
317	bucket = dlm_master_hash(dlm, i: mle->mnamehash);
318	hlist_add_head(n: &mle->master_hash_node, h: bucket);
319	}
320
321	/* returns 1 if found, 0 if not */
322	static int dlm_find_mle(struct dlm_ctxt *dlm,
323	struct dlm_master_list_entry **mle,
324	char *name, unsigned int namelen)
325	{
326	struct dlm_master_list_entry *tmpmle;
327	struct hlist_head *bucket;
328	unsigned int hash;
329
330	assert_spin_locked(&dlm->master_lock);
331
332	hash = dlm_lockid_hash(name, namelen);
333	bucket = dlm_master_hash(dlm, i: hash);
334	hlist_for_each_entry(tmpmle, bucket, master_hash_node) {
335	if (!dlm_mle_equal(dlm, mle: tmpmle, name, namelen))
336	continue;
337	dlm_get_mle(mle: tmpmle);
338	*mle = tmpmle;
339	return 1;
340	}
341	return 0;
342	}
343
344	void dlm_hb_event_notify_attached(struct dlm_ctxt *dlm, int idx, int node_up)
345	{
346	struct dlm_master_list_entry *mle;
347
348	assert_spin_locked(&dlm->spinlock);
349
350	list_for_each_entry(mle, &dlm->mle_hb_events, hb_events) {
351	if (node_up)
352	dlm_mle_node_up(dlm, mle, NULL, idx);
353	else
354	dlm_mle_node_down(dlm, mle, NULL, idx);
355	}
356	}
357
358	static void dlm_mle_node_down(struct dlm_ctxt *dlm,
359	struct dlm_master_list_entry *mle,
360	struct o2nm_node *node, int idx)
361	{
362	spin_lock(lock: &mle->spinlock);
363
364	if (!test_bit(idx, mle->node_map))
365	mlog(0, "node %u already removed from nodemap!\n", idx);
366	else
367	clear_bit(nr: idx, addr: mle->node_map);
368
369	spin_unlock(lock: &mle->spinlock);
370	}
371
372	static void dlm_mle_node_up(struct dlm_ctxt *dlm,
373	struct dlm_master_list_entry *mle,
374	struct o2nm_node *node, int idx)
375	{
376	spin_lock(lock: &mle->spinlock);
377
378	if (test_bit(idx, mle->node_map))
379	mlog(0, "node %u already in node map!\n", idx);
380	else
381	set_bit(nr: idx, addr: mle->node_map);
382
383	spin_unlock(lock: &mle->spinlock);
384	}
385
386
387	int dlm_init_mle_cache(void)
388	{
389	dlm_mle_cache = kmem_cache_create(name: "o2dlm_mle",
390	size: sizeof(struct dlm_master_list_entry),
391	align: 0, SLAB_HWCACHE_ALIGN,
392	NULL);
393	if (dlm_mle_cache == NULL)
394	return -ENOMEM;
395	return 0;
396	}
397
398	void dlm_destroy_mle_cache(void)
399	{
400	kmem_cache_destroy(s: dlm_mle_cache);
401	}
402
403	static void dlm_mle_release(struct kref *kref)
404	{
405	struct dlm_master_list_entry *mle;
406	struct dlm_ctxt *dlm;
407
408	mle = container_of(kref, struct dlm_master_list_entry, mle_refs);
409	dlm = mle->dlm;
410
411	assert_spin_locked(&dlm->spinlock);
412	assert_spin_locked(&dlm->master_lock);
413
414	mlog(0, "Releasing mle for %.*s, type %d\n", mle->mnamelen, mle->mname,
415	mle->type);
416
417	/* remove from list if not already */
418	__dlm_unlink_mle(dlm, mle);
419
420	/* detach the mle from the domain node up/down events */
421	__dlm_mle_detach_hb_events(dlm, mle);
422
423	atomic_dec(v: &dlm->mle_cur_count[mle->type]);
424
425	/* NOTE: kfree under spinlock here.
426	* if this is bad, we can move this to a freelist. */
427	kmem_cache_free(s: dlm_mle_cache, objp: mle);
428	}
429
430
431	/*
432	* LOCK RESOURCE FUNCTIONS
433	*/
434
435	int dlm_init_master_caches(void)
436	{
437	dlm_lockres_cache = kmem_cache_create(name: "o2dlm_lockres",
438	size: sizeof(struct dlm_lock_resource),
439	align: 0, SLAB_HWCACHE_ALIGN, NULL);
440	if (!dlm_lockres_cache)
441	goto bail;
442
443	dlm_lockname_cache = kmem_cache_create(name: "o2dlm_lockname",
444	DLM_LOCKID_NAME_MAX, align: 0,
445	SLAB_HWCACHE_ALIGN, NULL);
446	if (!dlm_lockname_cache)
447	goto bail;
448
449	return 0;
450	bail:
451	dlm_destroy_master_caches();
452	return -ENOMEM;
453	}
454
455	void dlm_destroy_master_caches(void)
456	{
457	kmem_cache_destroy(s: dlm_lockname_cache);
458	dlm_lockname_cache = NULL;
459
460	kmem_cache_destroy(s: dlm_lockres_cache);
461	dlm_lockres_cache = NULL;
462	}
463
464	static void dlm_lockres_release(struct kref *kref)
465	{
466	struct dlm_lock_resource *res;
467	struct dlm_ctxt *dlm;
468
469	res = container_of(kref, struct dlm_lock_resource, refs);
470	dlm = res->dlm;
471
472	/* This should not happen -- all lockres' have a name
473	* associated with them at init time. */
474	BUG_ON(!res->lockname.name);
475
476	mlog(0, "destroying lockres %.*s\n", res->lockname.len,
477	res->lockname.name);
478
479	atomic_dec(v: &dlm->res_cur_count);
480
481	if (!hlist_unhashed(h: &res->hash_node) ||
482	!list_empty(head: &res->granted) ||
483	!list_empty(head: &res->converting) ||
484	!list_empty(head: &res->blocked) ||
485	!list_empty(head: &res->dirty) ||
486	!list_empty(head: &res->recovering) ||
487	!list_empty(head: &res->purge)) {
488	mlog(ML_ERROR,
489	"Going to BUG for resource %.*s."
490	" We're on a list! [%c%c%c%c%c%c%c]\n",
491	res->lockname.len, res->lockname.name,
492	!hlist_unhashed(&res->hash_node) ? 'H' : ' ',
493	!list_empty(&res->granted) ? 'G' : ' ',
494	!list_empty(&res->converting) ? 'C' : ' ',
495	!list_empty(&res->blocked) ? 'B' : ' ',
496	!list_empty(&res->dirty) ? 'D' : ' ',
497	!list_empty(&res->recovering) ? 'R' : ' ',
498	!list_empty(&res->purge) ? 'P' : ' ');
499
500	dlm_print_one_lock_resource(res);
501	}
502
503	/* By the time we're ready to blow this guy away, we shouldn't
504	* be on any lists. */
505	BUG_ON(!hlist_unhashed(&res->hash_node));
506	BUG_ON(!list_empty(&res->granted));
507	BUG_ON(!list_empty(&res->converting));
508	BUG_ON(!list_empty(&res->blocked));
509	BUG_ON(!list_empty(&res->dirty));
510	BUG_ON(!list_empty(&res->recovering));
511	BUG_ON(!list_empty(&res->purge));
512
513	kmem_cache_free(s: dlm_lockname_cache, objp: (void *)res->lockname.name);
514
515	kmem_cache_free(s: dlm_lockres_cache, objp: res);
516	}
517
518	void dlm_lockres_put(struct dlm_lock_resource *res)
519	{
520	kref_put(kref: &res->refs, release: dlm_lockres_release);
521	}
522
523	static void dlm_init_lockres(struct dlm_ctxt *dlm,
524	struct dlm_lock_resource *res,
525	const char *name, unsigned int namelen)
526	{
527	char *qname;
528
529	/* If we memset here, we lose our reference to the kmalloc'd
530	* res->lockname.name, so be sure to init every field
531	* correctly! */
532
533	qname = (char *) res->lockname.name;
534	memcpy(qname, name, namelen);
535
536	res->lockname.len = namelen;
537	res->lockname.hash = dlm_lockid_hash(name, namelen);
538
539	init_waitqueue_head(&res->wq);
540	spin_lock_init(&res->spinlock);
541	INIT_HLIST_NODE(h: &res->hash_node);
542	INIT_LIST_HEAD(list: &res->granted);
543	INIT_LIST_HEAD(list: &res->converting);
544	INIT_LIST_HEAD(list: &res->blocked);
545	INIT_LIST_HEAD(list: &res->dirty);
546	INIT_LIST_HEAD(list: &res->recovering);
547	INIT_LIST_HEAD(list: &res->purge);
548	INIT_LIST_HEAD(list: &res->tracking);
549	atomic_set(v: &res->asts_reserved, i: 0);
550	res->migration_pending = 0;
551	res->inflight_locks = 0;
552	res->inflight_assert_workers = 0;
553
554	res->dlm = dlm;
555
556	kref_init(kref: &res->refs);
557
558	atomic_inc(v: &dlm->res_tot_count);
559	atomic_inc(v: &dlm->res_cur_count);
560
561	/* just for consistency */
562	spin_lock(lock: &res->spinlock);
563	dlm_set_lockres_owner(dlm, res, DLM_LOCK_RES_OWNER_UNKNOWN);
564	spin_unlock(lock: &res->spinlock);
565
566	res->state = DLM_LOCK_RES_IN_PROGRESS;
567
568	res->last_used = 0;
569
570	spin_lock(lock: &dlm->track_lock);
571	list_add_tail(new: &res->tracking, head: &dlm->tracking_list);
572	spin_unlock(lock: &dlm->track_lock);
573
574	memset(res->lvb, 0, DLM_LVB_LEN);
575	bitmap_zero(dst: res->refmap, O2NM_MAX_NODES);
576	}
577
578	struct dlm_lock_resource *dlm_new_lockres(struct dlm_ctxt *dlm,
579	const char *name,
580	unsigned int namelen)
581	{
582	struct dlm_lock_resource *res = NULL;
583
584	res = kmem_cache_zalloc(k: dlm_lockres_cache, GFP_NOFS);
585	if (!res)
586	goto error;
587
588	res->lockname.name = kmem_cache_zalloc(k: dlm_lockname_cache, GFP_NOFS);
589	if (!res->lockname.name)
590	goto error;
591
592	dlm_init_lockres(dlm, res, name, namelen);
593	return res;
594
595	error:
596	if (res)
597	kmem_cache_free(s: dlm_lockres_cache, objp: res);
598	return NULL;
599	}
600
601	void dlm_lockres_set_refmap_bit(struct dlm_ctxt *dlm,
602	struct dlm_lock_resource *res, int bit)
603	{
604	assert_spin_locked(&res->spinlock);
605
606	mlog(0, "res %.*s, set node %u, %ps()\n", res->lockname.len,
607	res->lockname.name, bit, __builtin_return_address(0));
608
609	set_bit(nr: bit, addr: res->refmap);
610	}
611
612	void dlm_lockres_clear_refmap_bit(struct dlm_ctxt *dlm,
613	struct dlm_lock_resource *res, int bit)
614	{
615	assert_spin_locked(&res->spinlock);
616
617	mlog(0, "res %.*s, clr node %u, %ps()\n", res->lockname.len,
618	res->lockname.name, bit, __builtin_return_address(0));
619
620	clear_bit(nr: bit, addr: res->refmap);
621	}
622
623	static void __dlm_lockres_grab_inflight_ref(struct dlm_ctxt *dlm,
624	struct dlm_lock_resource *res)
625	{
626	res->inflight_locks++;
627
628	mlog(0, "%s: res %.*s, inflight++: now %u, %ps()\n", dlm->name,
629	res->lockname.len, res->lockname.name, res->inflight_locks,
630	__builtin_return_address(0));
631	}
632
633	void dlm_lockres_grab_inflight_ref(struct dlm_ctxt *dlm,
634	struct dlm_lock_resource *res)
635	{
636	assert_spin_locked(&res->spinlock);
637	__dlm_lockres_grab_inflight_ref(dlm, res);
638	}
639
640	void dlm_lockres_drop_inflight_ref(struct dlm_ctxt *dlm,
641	struct dlm_lock_resource *res)
642	{
643	assert_spin_locked(&res->spinlock);
644
645	BUG_ON(res->inflight_locks == 0);
646
647	res->inflight_locks--;
648
649	mlog(0, "%s: res %.*s, inflight--: now %u, %ps()\n", dlm->name,
650	res->lockname.len, res->lockname.name, res->inflight_locks,
651	__builtin_return_address(0));
652
653	wake_up(&res->wq);
654	}
655
656	void __dlm_lockres_grab_inflight_worker(struct dlm_ctxt *dlm,
657	struct dlm_lock_resource *res)
658	{
659	assert_spin_locked(&res->spinlock);
660	res->inflight_assert_workers++;
661	mlog(0, "%s:%.*s: inflight assert worker++: now %u\n",
662	dlm->name, res->lockname.len, res->lockname.name,
663	res->inflight_assert_workers);
664	}
665
666	static void __dlm_lockres_drop_inflight_worker(struct dlm_ctxt *dlm,
667	struct dlm_lock_resource *res)
668	{
669	assert_spin_locked(&res->spinlock);
670	BUG_ON(res->inflight_assert_workers == 0);
671	res->inflight_assert_workers--;
672	mlog(0, "%s:%.*s: inflight assert worker--: now %u\n",
673	dlm->name, res->lockname.len, res->lockname.name,
674	res->inflight_assert_workers);
675	}
676
677	static void dlm_lockres_drop_inflight_worker(struct dlm_ctxt *dlm,
678	struct dlm_lock_resource *res)
679	{
680	spin_lock(lock: &res->spinlock);
681	__dlm_lockres_drop_inflight_worker(dlm, res);
682	spin_unlock(lock: &res->spinlock);
683	}
684
685	/*
686	* lookup a lock resource by name.
687	* may already exist in the hashtable.
688	* lockid is null terminated
689	*
690	* if not, allocate enough for the lockres and for
691	* the temporary structure used in doing the mastering.
692	*
693	* also, do a lookup in the dlm->master_list to see
694	* if another node has begun mastering the same lock.
695	* if so, there should be a block entry in there
696	* for this name, and we should *not* attempt to master
697	* the lock here. need to wait around for that node
698	* to assert_master (or die).
699	*
700	*/
701	struct dlm_lock_resource * dlm_get_lock_resource(struct dlm_ctxt *dlm,
702	const char *lockid,
703	int namelen,
704	int flags)
705	{
706	struct dlm_lock_resource *tmpres=NULL, *res=NULL;
707	struct dlm_master_list_entry *mle = NULL;
708	struct dlm_master_list_entry *alloc_mle = NULL;
709	int blocked = 0;
710	int ret, nodenum;
711	struct dlm_node_iter iter;
712	unsigned int hash;
713	int tries = 0;
714	int bit, wait_on_recovery = 0;
715
716	BUG_ON(!lockid);
717
718	hash = dlm_lockid_hash(lockid, namelen);
719
720	mlog(0, "get lockres %s (len %d)\n", lockid, namelen);
721
722	lookup:
723	spin_lock(lock: &dlm->spinlock);
724	tmpres = __dlm_lookup_lockres_full(dlm, name: lockid, len: namelen, hash);
725	if (tmpres) {
726	spin_unlock(lock: &dlm->spinlock);
727	spin_lock(lock: &tmpres->spinlock);
728
729	/*
730	* Right after dlm spinlock was released, dlm_thread could have
731	* purged the lockres. Check if lockres got unhashed. If so
732	* start over.
733	*/
734	if (hlist_unhashed(h: &tmpres->hash_node)) {
735	spin_unlock(lock: &tmpres->spinlock);
736	dlm_lockres_put(res: tmpres);
737	tmpres = NULL;
738	goto lookup;
739	}
740
741	/* Wait on the thread that is mastering the resource */
742	if (tmpres->owner == DLM_LOCK_RES_OWNER_UNKNOWN) {
743	__dlm_wait_on_lockres(res: tmpres);
744	BUG_ON(tmpres->owner == DLM_LOCK_RES_OWNER_UNKNOWN);
745	spin_unlock(lock: &tmpres->spinlock);
746	dlm_lockres_put(res: tmpres);
747	tmpres = NULL;
748	goto lookup;
749	}
750
751	/* Wait on the resource purge to complete before continuing */
752	if (tmpres->state & DLM_LOCK_RES_DROPPING_REF) {
753	BUG_ON(tmpres->owner == dlm->node_num);
754	__dlm_wait_on_lockres_flags(res: tmpres,
755	DLM_LOCK_RES_DROPPING_REF);
756	spin_unlock(lock: &tmpres->spinlock);
757	dlm_lockres_put(res: tmpres);
758	tmpres = NULL;
759	goto lookup;
760	}
761
762	/* Grab inflight ref to pin the resource */
763	dlm_lockres_grab_inflight_ref(dlm, res: tmpres);
764
765	spin_unlock(lock: &tmpres->spinlock);
766	if (res) {
767	spin_lock(lock: &dlm->track_lock);
768	if (!list_empty(head: &res->tracking))
769	list_del_init(entry: &res->tracking);
770	else
771	mlog(ML_ERROR, "Resource %.*s not "
772	"on the Tracking list\n",
773	res->lockname.len,
774	res->lockname.name);
775	spin_unlock(lock: &dlm->track_lock);
776	dlm_lockres_put(res);
777	}
778	res = tmpres;
779	goto leave;
780	}
781
782	if (!res) {
783	spin_unlock(lock: &dlm->spinlock);
784	mlog(0, "allocating a new resource\n");
785	/* nothing found and we need to allocate one. */
786	alloc_mle = kmem_cache_alloc(cachep: dlm_mle_cache, GFP_NOFS);
787	if (!alloc_mle)
788	goto leave;
789	res = dlm_new_lockres(dlm, name: lockid, namelen);
790	if (!res)
791	goto leave;
792	goto lookup;
793	}
794
795	mlog(0, "no lockres found, allocated our own: %p\n", res);
796
797	if (flags & LKM_LOCAL) {
798	/* caller knows it's safe to assume it's not mastered elsewhere
799	* DONE! return right away */
800	spin_lock(lock: &res->spinlock);
801	dlm_change_lockres_owner(dlm, res, owner: dlm->node_num);
802	__dlm_insert_lockres(dlm, res);
803	dlm_lockres_grab_inflight_ref(dlm, res);
804	spin_unlock(lock: &res->spinlock);
805	spin_unlock(lock: &dlm->spinlock);
806	/* lockres still marked IN_PROGRESS */
807	goto wake_waiters;
808	}
809
810	/* check master list to see if another node has started mastering it */
811	spin_lock(lock: &dlm->master_lock);
812
813	/* if we found a block, wait for lock to be mastered by another node */
814	blocked = dlm_find_mle(dlm, mle: &mle, name: (char *)lockid, namelen);
815	if (blocked) {
816	int mig;
817	if (mle->type == DLM_MLE_MASTER) {
818	mlog(ML_ERROR, "master entry for nonexistent lock!\n");
819	BUG();
820	}
821	mig = (mle->type == DLM_MLE_MIGRATION);
822	/* if there is a migration in progress, let the migration
823	* finish before continuing. we can wait for the absence
824	* of the MIGRATION mle: either the migrate finished or
825	* one of the nodes died and the mle was cleaned up.
826	* if there is a BLOCK here, but it already has a master
827	* set, we are too late. the master does not have a ref
828	* for us in the refmap. detach the mle and drop it.
829	* either way, go back to the top and start over. */
830	if (mig || mle->master != O2NM_MAX_NODES) {
831	BUG_ON(mig && mle->master == dlm->node_num);
832	/* we arrived too late. the master does not
833	* have a ref for us. retry. */
834	mlog(0, "%s:%.*s: late on %s\n",
835	dlm->name, namelen, lockid,
836	mig ? "MIGRATION" : "BLOCK");
837	spin_unlock(lock: &dlm->master_lock);
838	spin_unlock(lock: &dlm->spinlock);
839
840	/* master is known, detach */
841	if (!mig)
842	dlm_mle_detach_hb_events(dlm, mle);
843	dlm_put_mle(mle);
844	mle = NULL;
845	/* this is lame, but we can't wait on either
846	* the mle or lockres waitqueue here */
847	if (mig)
848	msleep(msecs: 100);
849	goto lookup;
850	}
851	} else {
852	/* go ahead and try to master lock on this node */
853	mle = alloc_mle;
854	/* make sure this does not get freed below */
855	alloc_mle = NULL;
856	dlm_init_mle(mle, type: DLM_MLE_MASTER, dlm, res, NULL, namelen: 0);
857	set_bit(nr: dlm->node_num, addr: mle->maybe_map);
858	__dlm_insert_mle(dlm, mle);
859
860	/* still holding the dlm spinlock, check the recovery map
861	* to see if there are any nodes that still need to be
862	* considered. these will not appear in the mle nodemap
863	* but they might own this lockres. wait on them. */
864	bit = find_first_bit(addr: dlm->recovery_map, O2NM_MAX_NODES);
865	if (bit < O2NM_MAX_NODES) {
866	mlog(0, "%s: res %.*s, At least one node (%d) "
867	"to recover before lock mastery can begin\n",
868	dlm->name, namelen, (char *)lockid, bit);
869	wait_on_recovery = 1;
870	}
871	}
872
873	/* at this point there is either a DLM_MLE_BLOCK or a
874	* DLM_MLE_MASTER on the master list, so it's safe to add the
875	* lockres to the hashtable. anyone who finds the lock will
876	* still have to wait on the IN_PROGRESS. */
877
878	/* finally add the lockres to its hash bucket */
879	__dlm_insert_lockres(dlm, res);
880
881	/* since this lockres is new it doesn't not require the spinlock */
882	__dlm_lockres_grab_inflight_ref(dlm, res);
883
884	/* get an extra ref on the mle in case this is a BLOCK
885	* if so, the creator of the BLOCK may try to put the last
886	* ref at this time in the assert master handler, so we
887	* need an extra one to keep from a bad ptr deref. */
888	dlm_get_mle_inuse(mle);
889	spin_unlock(lock: &dlm->master_lock);
890	spin_unlock(lock: &dlm->spinlock);
891
892	redo_request:
893	while (wait_on_recovery) {
894	/* any cluster changes that occurred after dropping the
895	* dlm spinlock would be detectable be a change on the mle,
896	* so we only need to clear out the recovery map once. */
897	if (dlm_is_recovery_lock(lock_name: lockid, name_len: namelen)) {
898	mlog(0, "%s: Recovery map is not empty, but must "
899	"master $RECOVERY lock now\n", dlm->name);
900	if (!dlm_pre_master_reco_lockres(dlm, res))
901	wait_on_recovery = 0;
902	else {
903	mlog(0, "%s: waiting 500ms for heartbeat state "
904	"change\n", dlm->name);
905	msleep(msecs: 500);
906	}
907	continue;
908	}
909
910	dlm_kick_recovery_thread(dlm);
911	msleep(msecs: 1000);
912	dlm_wait_for_recovery(dlm);
913
914	spin_lock(lock: &dlm->spinlock);
915	bit = find_first_bit(addr: dlm->recovery_map, O2NM_MAX_NODES);
916	if (bit < O2NM_MAX_NODES) {
917	mlog(0, "%s: res %.*s, At least one node (%d) "
918	"to recover before lock mastery can begin\n",
919	dlm->name, namelen, (char *)lockid, bit);
920	wait_on_recovery = 1;
921	} else
922	wait_on_recovery = 0;
923	spin_unlock(lock: &dlm->spinlock);
924
925	if (wait_on_recovery)
926	dlm_wait_for_node_recovery(dlm, node: bit, timeout: 10000);
927	}
928
929	/* must wait for lock to be mastered elsewhere */
930	if (blocked)
931	goto wait;
932
933	ret = -EINVAL;
934	dlm_node_iter_init(map: mle->vote_map, iter: &iter);
935	while ((nodenum = dlm_node_iter_next(iter: &iter)) >= 0) {
936	ret = dlm_do_master_request(res, mle, to: nodenum);
937	if (ret < 0)
938	mlog_errno(ret);
939	if (mle->master != O2NM_MAX_NODES) {
940	/* found a master ! */
941	if (mle->master <= nodenum)
942	break;
943	/* if our master request has not reached the master
944	* yet, keep going until it does. this is how the
945	* master will know that asserts are needed back to
946	* the lower nodes. */
947	mlog(0, "%s: res %.*s, Requests only up to %u but "
948	"master is %u, keep going\n", dlm->name, namelen,
949	lockid, nodenum, mle->master);
950	}
951	}
952
953	wait:
954	/* keep going until the response map includes all nodes */
955	ret = dlm_wait_for_lock_mastery(dlm, res, mle, blocked: &blocked);
956	if (ret < 0) {
957	wait_on_recovery = 1;
958	mlog(0, "%s: res %.*s, Node map changed, redo the master "
959	"request now, blocked=%d\n", dlm->name, res->lockname.len,
960	res->lockname.name, blocked);
961	if (++tries > 20) {
962	mlog(ML_ERROR, "%s: res %.*s, Spinning on "
963	"dlm_wait_for_lock_mastery, blocked = %d\n",
964	dlm->name, res->lockname.len,
965	res->lockname.name, blocked);
966	dlm_print_one_lock_resource(res);
967	dlm_print_one_mle(mle);
968	tries = 0;
969	}
970	goto redo_request;
971	}
972
973	mlog(0, "%s: res %.*s, Mastered by %u\n", dlm->name, res->lockname.len,
974	res->lockname.name, res->owner);
975	/* make sure we never continue without this */
976	BUG_ON(res->owner == O2NM_MAX_NODES);
977
978	/* master is known, detach if not already detached */
979	dlm_mle_detach_hb_events(dlm, mle);
980	dlm_put_mle(mle);
981	/* put the extra ref */
982	dlm_put_mle_inuse(mle);
983
984	wake_waiters:
985	spin_lock(lock: &res->spinlock);
986	res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
987	spin_unlock(lock: &res->spinlock);
988	wake_up(&res->wq);
989
990	leave:
991	/* need to free the unused mle */
992	if (alloc_mle)
993	kmem_cache_free(s: dlm_mle_cache, objp: alloc_mle);
994
995	return res;
996	}
997
998
999	#define DLM_MASTERY_TIMEOUT_MS 5000
1000
1001	static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
1002	struct dlm_lock_resource *res,
1003	struct dlm_master_list_entry *mle,
1004	int *blocked)
1005	{
1006	u8 m;
1007	int ret, bit;
1008	int map_changed, voting_done;
1009	int assert, sleep;
1010
1011	recheck:
1012	ret = 0;
1013	assert = 0;
1014
1015	/* check if another node has already become the owner */
1016	spin_lock(lock: &res->spinlock);
1017	if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1018	mlog(0, "%s:%.*s: owner is suddenly %u\n", dlm->name,
1019	res->lockname.len, res->lockname.name, res->owner);
1020	spin_unlock(lock: &res->spinlock);
1021	/* this will cause the master to re-assert across
1022	* the whole cluster, freeing up mles */
1023	if (res->owner != dlm->node_num) {
1024	ret = dlm_do_master_request(res, mle, to: res->owner);
1025	if (ret < 0) {
1026	/* give recovery a chance to run */
1027	mlog(ML_ERROR, "link to %u went down?: %d\n", res->owner, ret);
1028	msleep(msecs: 500);
1029	goto recheck;
1030	}
1031	}
1032	ret = 0;
1033	goto leave;
1034	}
1035	spin_unlock(lock: &res->spinlock);
1036
1037	spin_lock(lock: &mle->spinlock);
1038	m = mle->master;
1039	map_changed = !bitmap_equal(src1: mle->vote_map, src2: mle->node_map,
1040	O2NM_MAX_NODES);
1041	voting_done = bitmap_equal(src1: mle->vote_map, src2: mle->response_map,
1042	O2NM_MAX_NODES);
1043
1044	/* restart if we hit any errors */
1045	if (map_changed) {
1046	int b;
1047	mlog(0, "%s: %.*s: node map changed, restarting\n",
1048	dlm->name, res->lockname.len, res->lockname.name);
1049	ret = dlm_restart_lock_mastery(dlm, res, mle, blocked: *blocked);
1050	b = (mle->type == DLM_MLE_BLOCK);
1051	if ((*blocked && !b) || (!*blocked && b)) {
1052	mlog(0, "%s:%.*s: status change: old=%d new=%d\n",
1053	dlm->name, res->lockname.len, res->lockname.name,
1054	*blocked, b);
1055	*blocked = b;
1056	}
1057	spin_unlock(lock: &mle->spinlock);
1058	if (ret < 0) {
1059	mlog_errno(ret);
1060	goto leave;
1061	}
1062	mlog(0, "%s:%.*s: restart lock mastery succeeded, "
1063	"rechecking now\n", dlm->name, res->lockname.len,
1064	res->lockname.name);
1065	goto recheck;
1066	} else {
1067	if (!voting_done) {
1068	mlog(0, "map not changed and voting not done "
1069	"for %s:%.*s\n", dlm->name, res->lockname.len,
1070	res->lockname.name);
1071	}
1072	}
1073
1074	if (m != O2NM_MAX_NODES) {
1075	/* another node has done an assert!
1076	* all done! */
1077	sleep = 0;
1078	} else {
1079	sleep = 1;
1080	/* have all nodes responded? */
1081	if (voting_done && !*blocked) {
1082	bit = find_first_bit(addr: mle->maybe_map, O2NM_MAX_NODES);
1083	if (dlm->node_num <= bit) {
1084	/* my node number is lowest.
1085	* now tell other nodes that I am
1086	* mastering this. */
1087	mle->master = dlm->node_num;
1088	/* ref was grabbed in get_lock_resource
1089	* will be dropped in dlmlock_master */
1090	assert = 1;
1091	sleep = 0;
1092	}
1093	/* if voting is done, but we have not received
1094	* an assert master yet, we must sleep */
1095	}
1096	}
1097
1098	spin_unlock(lock: &mle->spinlock);
1099
1100	/* sleep if we haven't finished voting yet */
1101	if (sleep) {
1102	unsigned long timeo = msecs_to_jiffies(DLM_MASTERY_TIMEOUT_MS);
1103	atomic_set(v: &mle->woken, i: 0);
1104	(void)wait_event_timeout(mle->wq,
1105	(atomic_read(&mle->woken) == 1),
1106	timeo);
1107	if (res->owner == O2NM_MAX_NODES) {
1108	mlog(0, "%s:%.*s: waiting again\n", dlm->name,
1109	res->lockname.len, res->lockname.name);
1110	goto recheck;
1111	}
1112	mlog(0, "done waiting, master is %u\n", res->owner);
1113	ret = 0;
1114	goto leave;
1115	}
1116
1117	ret = 0; /* done */
1118	if (assert) {
1119	m = dlm->node_num;
1120	mlog(0, "about to master %.*s here, this=%u\n",
1121	res->lockname.len, res->lockname.name, m);
1122	ret = dlm_do_assert_master(dlm, res, nodemap: mle->vote_map, flags: 0);
1123	if (ret) {
1124	/* This is a failure in the network path,
1125	* not in the response to the assert_master
1126	* (any nonzero response is a BUG on this node).
1127	* Most likely a socket just got disconnected
1128	* due to node death. */
1129	mlog_errno(ret);
1130	}
1131	/* no longer need to restart lock mastery.
1132	* all living nodes have been contacted. */
1133	ret = 0;
1134	}
1135
1136	/* set the lockres owner */
1137	spin_lock(lock: &res->spinlock);
1138	/* mastery reference obtained either during
1139	* assert_master_handler or in get_lock_resource */
1140	dlm_change_lockres_owner(dlm, res, owner: m);
1141	spin_unlock(lock: &res->spinlock);
1142
1143	leave:
1144	return ret;
1145	}
1146
1147	struct dlm_bitmap_diff_iter
1148	{
1149	int curnode;
1150	unsigned long *orig_bm;
1151	unsigned long *cur_bm;
1152	unsigned long diff_bm[BITS_TO_LONGS(O2NM_MAX_NODES)];
1153	};
1154
1155	enum dlm_node_state_change
1156	{
1157	NODE_DOWN = -1,
1158	NODE_NO_CHANGE = 0,
1159	NODE_UP
1160	};
1161
1162	static void dlm_bitmap_diff_iter_init(struct dlm_bitmap_diff_iter *iter,
1163	unsigned long *orig_bm,
1164	unsigned long *cur_bm)
1165	{
1166	unsigned long p1, p2;
1167	int i;
1168
1169	iter->curnode = -1;
1170	iter->orig_bm = orig_bm;
1171	iter->cur_bm = cur_bm;
1172
1173	for (i = 0; i < BITS_TO_LONGS(O2NM_MAX_NODES); i++) {
1174	p1 = *(iter->orig_bm + i);
1175	p2 = *(iter->cur_bm + i);
1176	iter->diff_bm[i] = (p1 & ~p2) | (p2 & ~p1);
1177	}
1178	}
1179
1180	static int dlm_bitmap_diff_iter_next(struct dlm_bitmap_diff_iter *iter,
1181	enum dlm_node_state_change *state)
1182	{
1183	int bit;
1184
1185	if (iter->curnode >= O2NM_MAX_NODES)
1186	return -ENOENT;
1187
1188	bit = find_next_bit(addr: iter->diff_bm, O2NM_MAX_NODES,
1189	offset: iter->curnode+1);
1190	if (bit >= O2NM_MAX_NODES) {
1191	iter->curnode = O2NM_MAX_NODES;
1192	return -ENOENT;
1193	}
1194
1195	/* if it was there in the original then this node died */
1196	if (test_bit(bit, iter->orig_bm))
1197	*state = NODE_DOWN;
1198	else
1199	*state = NODE_UP;
1200
1201	iter->curnode = bit;
1202	return bit;
1203	}
1204
1205
1206	static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
1207	struct dlm_lock_resource *res,
1208	struct dlm_master_list_entry *mle,
1209	int blocked)
1210	{
1211	struct dlm_bitmap_diff_iter bdi;
1212	enum dlm_node_state_change sc;
1213	int node;
1214	int ret = 0;
1215
1216	mlog(0, "something happened such that the "
1217	"master process may need to be restarted!\n");
1218
1219	assert_spin_locked(&mle->spinlock);
1220
1221	dlm_bitmap_diff_iter_init(iter: &bdi, orig_bm: mle->vote_map, cur_bm: mle->node_map);
1222	node = dlm_bitmap_diff_iter_next(iter: &bdi, state: &sc);
1223	while (node >= 0) {
1224	if (sc == NODE_UP) {
1225	/* a node came up. clear any old vote from
1226	* the response map and set it in the vote map
1227	* then restart the mastery. */
1228	mlog(ML_NOTICE, "node %d up while restarting\n", node);
1229
1230	/* redo the master request, but only for the new node */
1231	mlog(0, "sending request to new node\n");
1232	clear_bit(nr: node, addr: mle->response_map);
1233	set_bit(nr: node, addr: mle->vote_map);
1234	} else {
1235	mlog(ML_ERROR, "node down! %d\n", node);
1236	if (blocked) {
1237	int lowest = find_first_bit(addr: mle->maybe_map,
1238	O2NM_MAX_NODES);
1239
1240	/* act like it was never there */
1241	clear_bit(nr: node, addr: mle->maybe_map);
1242
1243	if (node == lowest) {
1244	mlog(0, "expected master %u died"
1245	" while this node was blocked "
1246	"waiting on it!\n", node);
1247	lowest = find_next_bit(addr: mle->maybe_map,
1248	O2NM_MAX_NODES,
1249	offset: lowest+1);
1250	if (lowest < O2NM_MAX_NODES) {
1251	mlog(0, "%s:%.*s:still "
1252	"blocked. waiting on %u "
1253	"now\n", dlm->name,
1254	res->lockname.len,
1255	res->lockname.name,
1256	lowest);
1257	} else {
1258	/* mle is an MLE_BLOCK, but
1259	* there is now nothing left to
1260	* block on. we need to return
1261	* all the way back out and try
1262	* again with an MLE_MASTER.
1263	* dlm_do_local_recovery_cleanup
1264	* has already run, so the mle
1265	* refcount is ok */
1266	mlog(0, "%s:%.*s: no "
1267	"longer blocking. try to "
1268	"master this here\n",
1269	dlm->name,
1270	res->lockname.len,
1271	res->lockname.name);
1272	mle->type = DLM_MLE_MASTER;
1273	mle->mleres = res;
1274	}
1275	}
1276	}
1277
1278	/* now blank out everything, as if we had never
1279	* contacted anyone */
1280	bitmap_zero(dst: mle->maybe_map, O2NM_MAX_NODES);
1281	bitmap_zero(dst: mle->response_map, O2NM_MAX_NODES);
1282	/* reset the vote_map to the current node_map */
1283	bitmap_copy(dst: mle->vote_map, src: mle->node_map,
1284	O2NM_MAX_NODES);
1285	/* put myself into the maybe map */
1286	if (mle->type != DLM_MLE_BLOCK)
1287	set_bit(nr: dlm->node_num, addr: mle->maybe_map);
1288	}
1289	ret = -EAGAIN;
1290	node = dlm_bitmap_diff_iter_next(iter: &bdi, state: &sc);
1291	}
1292	return ret;
1293	}
1294
1295
1296	/*
1297	* DLM_MASTER_REQUEST_MSG
1298	*
1299	* returns: 0 on success,
1300	* -errno on a network error
1301	*
1302	* on error, the caller should assume the target node is "dead"
1303	*
1304	*/
1305
1306	static int dlm_do_master_request(struct dlm_lock_resource *res,
1307	struct dlm_master_list_entry *mle, int to)
1308	{
1309	struct dlm_ctxt *dlm = mle->dlm;
1310	struct dlm_master_request request;
1311	int ret, response=0, resend;
1312
1313	memset(&request, 0, sizeof(request));
1314	request.node_idx = dlm->node_num;
1315
1316	BUG_ON(mle->type == DLM_MLE_MIGRATION);
1317
1318	request.namelen = (u8)mle->mnamelen;
1319	memcpy(request.name, mle->mname, request.namelen);
1320
1321	again:
1322	ret = o2net_send_message(msg_type: DLM_MASTER_REQUEST_MSG, key: dlm->key, data: &request,
1323	len: sizeof(request), target_node: to, status: &response);
1324	if (ret < 0) {
1325	if (ret == -ESRCH) {
1326	/* should never happen */
1327	mlog(ML_ERROR, "TCP stack not ready!\n");
1328	BUG();
1329	} else if (ret == -EINVAL) {
1330	mlog(ML_ERROR, "bad args passed to o2net!\n");
1331	BUG();
1332	} else if (ret == -ENOMEM) {
1333	mlog(ML_ERROR, "out of memory while trying to send "
1334	"network message! retrying\n");
1335	/* this is totally crude */
1336	msleep(msecs: 50);
1337	goto again;
1338	} else if (!dlm_is_host_down(errno: ret)) {
1339	/* not a network error. bad. */
1340	mlog_errno(ret);
1341	mlog(ML_ERROR, "unhandled error!");
1342	BUG();
1343	}
1344	/* all other errors should be network errors,
1345	* and likely indicate node death */
1346	mlog(ML_ERROR, "link to %d went down!\n", to);
1347	goto out;
1348	}
1349
1350	ret = 0;
1351	resend = 0;
1352	spin_lock(lock: &mle->spinlock);
1353	switch (response) {
1354	case DLM_MASTER_RESP_YES:
1355	set_bit(nr: to, addr: mle->response_map);
1356	mlog(0, "node %u is the master, response=YES\n", to);
1357	mlog(0, "%s:%.*s: master node %u now knows I have a "
1358	"reference\n", dlm->name, res->lockname.len,
1359	res->lockname.name, to);
1360	mle->master = to;
1361	break;
1362	case DLM_MASTER_RESP_NO:
1363	mlog(0, "node %u not master, response=NO\n", to);
1364	set_bit(nr: to, addr: mle->response_map);
1365	break;
1366	case DLM_MASTER_RESP_MAYBE:
1367	mlog(0, "node %u not master, response=MAYBE\n", to);
1368	set_bit(nr: to, addr: mle->response_map);
1369	set_bit(nr: to, addr: mle->maybe_map);
1370	break;
1371	case DLM_MASTER_RESP_ERROR:
1372	mlog(0, "node %u hit an error, resending\n", to);
1373	resend = 1;
1374	response = 0;
1375	break;
1376	default:
1377	mlog(ML_ERROR, "bad response! %u\n", response);
1378	BUG();
1379	}
1380	spin_unlock(lock: &mle->spinlock);
1381	if (resend) {
1382	/* this is also totally crude */
1383	msleep(msecs: 50);
1384	goto again;
1385	}
1386
1387	out:
1388	return ret;
1389	}
1390
1391	/*
1392	* locks that can be taken here:
1393	* dlm->spinlock
1394	* res->spinlock
1395	* mle->spinlock
1396	* dlm->master_list
1397	*
1398	* if possible, TRIM THIS DOWN!!!
1399	*/
1400	int dlm_master_request_handler(struct o2net_msg *msg, u32 len, void *data,
1401	void **ret_data)
1402	{
1403	u8 response = DLM_MASTER_RESP_MAYBE;
1404	struct dlm_ctxt *dlm = data;
1405	struct dlm_lock_resource *res = NULL;
1406	struct dlm_master_request *request = (struct dlm_master_request *) msg->buf;
1407	struct dlm_master_list_entry *mle = NULL, *tmpmle = NULL;
1408	char *name;
1409	unsigned int namelen, hash;
1410	int found, ret;
1411	int set_maybe;
1412	int dispatch_assert = 0;
1413	int dispatched = 0;
1414
1415	if (!dlm_grab(dlm))
1416	return DLM_MASTER_RESP_NO;
1417
1418	if (!dlm_domain_fully_joined(dlm)) {
1419	response = DLM_MASTER_RESP_NO;
1420	goto send_response;
1421	}
1422
1423	name = request->name;
1424	namelen = request->namelen;
1425	hash = dlm_lockid_hash(name, namelen);
1426
1427	if (namelen > DLM_LOCKID_NAME_MAX) {
1428	response = DLM_IVBUFLEN;
1429	goto send_response;
1430	}
1431
1432	way_up_top:
1433	spin_lock(lock: &dlm->spinlock);
1434	res = __dlm_lookup_lockres(dlm, name, len: namelen, hash);
1435	if (res) {
1436	spin_unlock(lock: &dlm->spinlock);
1437
1438	/* take care of the easy cases up front */
1439	spin_lock(lock: &res->spinlock);
1440
1441	/*
1442	* Right after dlm spinlock was released, dlm_thread could have
1443	* purged the lockres. Check if lockres got unhashed. If so
1444	* start over.
1445	*/
1446	if (hlist_unhashed(h: &res->hash_node)) {
1447	spin_unlock(lock: &res->spinlock);
1448	dlm_lockres_put(res);
1449	goto way_up_top;
1450	}
1451
1452	if (res->state & (DLM_LOCK_RES_RECOVERING|
1453	DLM_LOCK_RES_MIGRATING)) {
1454	spin_unlock(lock: &res->spinlock);
1455	mlog(0, "returning DLM_MASTER_RESP_ERROR since res is "
1456	"being recovered/migrated\n");
1457	response = DLM_MASTER_RESP_ERROR;
1458	if (mle)
1459	kmem_cache_free(s: dlm_mle_cache, objp: mle);
1460	goto send_response;
1461	}
1462
1463	if (res->owner == dlm->node_num) {
1464	dlm_lockres_set_refmap_bit(dlm, res, bit: request->node_idx);
1465	spin_unlock(lock: &res->spinlock);
1466	response = DLM_MASTER_RESP_YES;
1467	if (mle)
1468	kmem_cache_free(s: dlm_mle_cache, objp: mle);
1469
1470	/* this node is the owner.
1471	* there is some extra work that needs to
1472	* happen now. the requesting node has
1473	* caused all nodes up to this one to
1474	* create mles. this node now needs to
1475	* go back and clean those up. */
1476	dispatch_assert = 1;
1477	goto send_response;
1478	} else if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1479	spin_unlock(lock: &res->spinlock);
1480	// mlog(0, "node %u is the master\n", res->owner);
1481	response = DLM_MASTER_RESP_NO;
1482	if (mle)
1483	kmem_cache_free(s: dlm_mle_cache, objp: mle);
1484	goto send_response;
1485	}
1486
1487	/* ok, there is no owner. either this node is
1488	* being blocked, or it is actively trying to
1489	* master this lock. */
1490	if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
1491	mlog(ML_ERROR, "lock with no owner should be "
1492	"in-progress!\n");
1493	BUG();
1494	}
1495
1496	// mlog(0, "lockres is in progress...\n");
1497	spin_lock(lock: &dlm->master_lock);
1498	found = dlm_find_mle(dlm, mle: &tmpmle, name, namelen);
1499	if (!found) {
1500	mlog(ML_ERROR, "no mle found for this lock!\n");
1501	BUG();
1502	}
1503	set_maybe = 1;
1504	spin_lock(lock: &tmpmle->spinlock);
1505	if (tmpmle->type == DLM_MLE_BLOCK) {
1506	// mlog(0, "this node is waiting for "
1507	// "lockres to be mastered\n");
1508	response = DLM_MASTER_RESP_NO;
1509	} else if (tmpmle->type == DLM_MLE_MIGRATION) {
1510	mlog(0, "node %u is master, but trying to migrate to "
1511	"node %u.\n", tmpmle->master, tmpmle->new_master);
1512	if (tmpmle->master == dlm->node_num) {
1513	mlog(ML_ERROR, "no owner on lockres, but this "
1514	"node is trying to migrate it to %u?!\n",
1515	tmpmle->new_master);
1516	BUG();
1517	} else {
1518	/* the real master can respond on its own */
1519	response = DLM_MASTER_RESP_NO;
1520	}
1521	} else if (tmpmle->master != DLM_LOCK_RES_OWNER_UNKNOWN) {
1522	set_maybe = 0;
1523	if (tmpmle->master == dlm->node_num) {
1524	response = DLM_MASTER_RESP_YES;
1525	/* this node will be the owner.
1526	* go back and clean the mles on any
1527	* other nodes */
1528	dispatch_assert = 1;
1529	dlm_lockres_set_refmap_bit(dlm, res,
1530	bit: request->node_idx);
1531	} else
1532	response = DLM_MASTER_RESP_NO;
1533	} else {
1534	// mlog(0, "this node is attempting to "
1535	// "master lockres\n");
1536	response = DLM_MASTER_RESP_MAYBE;
1537	}
1538	if (set_maybe)
1539	set_bit(nr: request->node_idx, addr: tmpmle->maybe_map);
1540	spin_unlock(lock: &tmpmle->spinlock);
1541
1542	spin_unlock(lock: &dlm->master_lock);
1543	spin_unlock(lock: &res->spinlock);
1544
1545	/* keep the mle attached to heartbeat events */
1546	dlm_put_mle(mle: tmpmle);
1547	if (mle)
1548	kmem_cache_free(s: dlm_mle_cache, objp: mle);
1549	goto send_response;
1550	}
1551
1552	/*
1553	* lockres doesn't exist on this node
1554	* if there is an MLE_BLOCK, return NO
1555	* if there is an MLE_MASTER, return MAYBE
1556	* otherwise, add an MLE_BLOCK, return NO
1557	*/
1558	spin_lock(lock: &dlm->master_lock);
1559	found = dlm_find_mle(dlm, mle: &tmpmle, name, namelen);
1560	if (!found) {
1561	/* this lockid has never been seen on this node yet */
1562	// mlog(0, "no mle found\n");
1563	if (!mle) {
1564	spin_unlock(lock: &dlm->master_lock);
1565	spin_unlock(lock: &dlm->spinlock);
1566
1567	mle = kmem_cache_alloc(cachep: dlm_mle_cache, GFP_NOFS);
1568	if (!mle) {
1569	response = DLM_MASTER_RESP_ERROR;
1570	mlog_errno(-ENOMEM);
1571	goto send_response;
1572	}
1573	goto way_up_top;
1574	}
1575
1576	// mlog(0, "this is second time thru, already allocated, "
1577	// "add the block.\n");
1578	dlm_init_mle(mle, type: DLM_MLE_BLOCK, dlm, NULL, name, namelen);
1579	set_bit(nr: request->node_idx, addr: mle->maybe_map);
1580	__dlm_insert_mle(dlm, mle);
1581	response = DLM_MASTER_RESP_NO;
1582	} else {
1583	spin_lock(lock: &tmpmle->spinlock);
1584	if (tmpmle->master == dlm->node_num) {
1585	mlog(ML_ERROR, "no lockres, but an mle with this node as master!\n");
1586	BUG();
1587	}
1588	if (tmpmle->type == DLM_MLE_BLOCK)
1589	response = DLM_MASTER_RESP_NO;
1590	else if (tmpmle->type == DLM_MLE_MIGRATION) {
1591	mlog(0, "migration mle was found (%u->%u)\n",
1592	tmpmle->master, tmpmle->new_master);
1593	/* real master can respond on its own */
1594	response = DLM_MASTER_RESP_NO;
1595	} else
1596	response = DLM_MASTER_RESP_MAYBE;
1597	set_bit(nr: request->node_idx, addr: tmpmle->maybe_map);
1598	spin_unlock(lock: &tmpmle->spinlock);
1599	}
1600	spin_unlock(lock: &dlm->master_lock);
1601	spin_unlock(lock: &dlm->spinlock);
1602
1603	if (found) {
1604	/* keep the mle attached to heartbeat events */
1605	dlm_put_mle(mle: tmpmle);
1606	}
1607	send_response:
1608	/*
1609	* __dlm_lookup_lockres() grabbed a reference to this lockres.
1610	* The reference is released by dlm_assert_master_worker() under
1611	* the call to dlm_dispatch_assert_master(). If
1612	* dlm_assert_master_worker() isn't called, we drop it here.
1613	*/
1614	if (dispatch_assert) {
1615	mlog(0, "%u is the owner of %.*s, cleaning everyone else\n",
1616	dlm->node_num, res->lockname.len, res->lockname.name);
1617	spin_lock(lock: &res->spinlock);
1618	ret = dlm_dispatch_assert_master(dlm, res, ignore_higher: 0, request_from: request->node_idx,
1619	DLM_ASSERT_MASTER_MLE_CLEANUP);
1620	if (ret < 0) {
1621	mlog(ML_ERROR, "failed to dispatch assert master work\n");
1622	response = DLM_MASTER_RESP_ERROR;
1623	spin_unlock(lock: &res->spinlock);
1624	dlm_lockres_put(res);
1625	} else {
1626	dispatched = 1;
1627	__dlm_lockres_grab_inflight_worker(dlm, res);
1628	spin_unlock(lock: &res->spinlock);
1629	}
1630	} else {
1631	if (res)
1632	dlm_lockres_put(res);
1633	}
1634
1635	if (!dispatched)
1636	dlm_put(dlm);
1637	return response;
1638	}
1639
1640	/*
1641	* DLM_ASSERT_MASTER_MSG
1642	*/
1643
1644
1645	/*
1646	* NOTE: this can be used for debugging
1647	* can periodically run all locks owned by this node
1648	* and re-assert across the cluster...
1649	*/
1650	static int dlm_do_assert_master(struct dlm_ctxt *dlm,
1651	struct dlm_lock_resource *res,
1652	void *nodemap, u32 flags)
1653	{
1654	struct dlm_assert_master assert;
1655	int to, tmpret;
1656	struct dlm_node_iter iter;
1657	int ret = 0;
1658	int reassert;
1659	const char *lockname = res->lockname.name;
1660	unsigned int namelen = res->lockname.len;
1661
1662	BUG_ON(namelen > O2NM_MAX_NAME_LEN);
1663
1664	spin_lock(lock: &res->spinlock);
1665	res->state |= DLM_LOCK_RES_SETREF_INPROG;
1666	spin_unlock(lock: &res->spinlock);
1667
1668	again:
1669	reassert = 0;
1670
1671	/* note that if this nodemap is empty, it returns 0 */
1672	dlm_node_iter_init(map: nodemap, iter: &iter);
1673	while ((to = dlm_node_iter_next(iter: &iter)) >= 0) {
1674	int r = 0;
1675	struct dlm_master_list_entry *mle = NULL;
1676
1677	mlog(0, "sending assert master to %d (%.*s)\n", to,
1678	namelen, lockname);
1679	memset(&assert, 0, sizeof(assert));
1680	assert.node_idx = dlm->node_num;
1681	assert.namelen = namelen;
1682	memcpy(assert.name, lockname, namelen);
1683	assert.flags = cpu_to_be32(flags);
1684
1685	tmpret = o2net_send_message(msg_type: DLM_ASSERT_MASTER_MSG, key: dlm->key,
1686	data: &assert, len: sizeof(assert), target_node: to, status: &r);
1687	if (tmpret < 0) {
1688	mlog(ML_ERROR, "Error %d when sending message %u (key "
1689	"0x%x) to node %u\n", tmpret,
1690	DLM_ASSERT_MASTER_MSG, dlm->key, to);
1691	if (!dlm_is_host_down(errno: tmpret)) {
1692	mlog(ML_ERROR, "unhandled error=%d!\n", tmpret);
1693	BUG();
1694	}
1695	/* a node died. finish out the rest of the nodes. */
1696	mlog(0, "link to %d went down!\n", to);
1697	/* any nonzero status return will do */
1698	ret = tmpret;
1699	r = 0;
1700	} else if (r < 0) {
1701	/* ok, something horribly messed. kill thyself. */
1702	mlog(ML_ERROR,"during assert master of %.*s to %u, "
1703	"got %d.\n", namelen, lockname, to, r);
1704	spin_lock(lock: &dlm->spinlock);
1705	spin_lock(lock: &dlm->master_lock);
1706	if (dlm_find_mle(dlm, mle: &mle, name: (char *)lockname,
1707	namelen)) {
1708	dlm_print_one_mle(mle);
1709	__dlm_put_mle(mle);
1710	}
1711	spin_unlock(lock: &dlm->master_lock);
1712	spin_unlock(lock: &dlm->spinlock);
1713	BUG();
1714	}
1715
1716	if (r & DLM_ASSERT_RESPONSE_REASSERT &&
1717	!(r & DLM_ASSERT_RESPONSE_MASTERY_REF)) {
1718	mlog(ML_ERROR, "%.*s: very strange, "
1719	"master MLE but no lockres on %u\n",
1720	namelen, lockname, to);
1721	}
1722
1723	if (r & DLM_ASSERT_RESPONSE_REASSERT) {
1724	mlog(0, "%.*s: node %u create mles on other "
1725	"nodes and requests a re-assert\n",
1726	namelen, lockname, to);
1727	reassert = 1;
1728	}
1729	if (r & DLM_ASSERT_RESPONSE_MASTERY_REF) {
1730	mlog(0, "%.*s: node %u has a reference to this "
1731	"lockres, set the bit in the refmap\n",
1732	namelen, lockname, to);
1733	spin_lock(lock: &res->spinlock);
1734	dlm_lockres_set_refmap_bit(dlm, res, bit: to);
1735	spin_unlock(lock: &res->spinlock);
1736	}
1737	}
1738
1739	if (reassert)
1740	goto again;
1741
1742	spin_lock(lock: &res->spinlock);
1743	res->state &= ~DLM_LOCK_RES_SETREF_INPROG;
1744	spin_unlock(lock: &res->spinlock);
1745	wake_up(&res->wq);
1746
1747	return ret;
1748	}
1749
1750	/*
1751	* locks that can be taken here:
1752	* dlm->spinlock
1753	* res->spinlock
1754	* mle->spinlock
1755	* dlm->master_list
1756	*
1757	* if possible, TRIM THIS DOWN!!!
1758	*/
1759	int dlm_assert_master_handler(struct o2net_msg *msg, u32 len, void *data,
1760	void **ret_data)
1761	{
1762	struct dlm_ctxt *dlm = data;
1763	struct dlm_master_list_entry *mle = NULL;
1764	struct dlm_assert_master *assert = (struct dlm_assert_master *)msg->buf;
1765	struct dlm_lock_resource *res = NULL;
1766	char *name;
1767	unsigned int namelen, hash;
1768	u32 flags;
1769	int master_request = 0, have_lockres_ref = 0;
1770	int ret = 0;
1771
1772	if (!dlm_grab(dlm))
1773	return 0;
1774
1775	name = assert->name;
1776	namelen = assert->namelen;
1777	hash = dlm_lockid_hash(name, namelen);
1778	flags = be32_to_cpu(assert->flags);
1779
1780	if (namelen > DLM_LOCKID_NAME_MAX) {
1781	mlog(ML_ERROR, "Invalid name length!");
1782	goto done;
1783	}
1784
1785	spin_lock(lock: &dlm->spinlock);
1786
1787	if (flags)
1788	mlog(0, "assert_master with flags: %u\n", flags);
1789
1790	/* find the MLE */
1791	spin_lock(lock: &dlm->master_lock);
1792	if (!dlm_find_mle(dlm, mle: &mle, name, namelen)) {
1793	/* not an error, could be master just re-asserting */
1794	mlog(0, "just got an assert_master from %u, but no "
1795	"MLE for it! (%.*s)\n", assert->node_idx,
1796	namelen, name);
1797	} else {
1798	int bit = find_first_bit(addr: mle->maybe_map, O2NM_MAX_NODES);
1799	if (bit >= O2NM_MAX_NODES) {
1800	/* not necessarily an error, though less likely.
1801	* could be master just re-asserting. */
1802	mlog(0, "no bits set in the maybe_map, but %u "
1803	"is asserting! (%.*s)\n", assert->node_idx,
1804	namelen, name);
1805	} else if (bit != assert->node_idx) {
1806	if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
1807	mlog(0, "master %u was found, %u should "
1808	"back off\n", assert->node_idx, bit);
1809	} else {
1810	/* with the fix for bug 569, a higher node
1811	* number winning the mastery will respond
1812	* YES to mastery requests, but this node
1813	* had no way of knowing. let it pass. */
1814	mlog(0, "%u is the lowest node, "
1815	"%u is asserting. (%.*s) %u must "
1816	"have begun after %u won.\n", bit,
1817	assert->node_idx, namelen, name, bit,
1818	assert->node_idx);
1819	}
1820	}
1821	if (mle->type == DLM_MLE_MIGRATION) {
1822	if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
1823	mlog(0, "%s:%.*s: got cleanup assert"
1824	" from %u for migration\n",
1825	dlm->name, namelen, name,
1826	assert->node_idx);
1827	} else if (!(flags & DLM_ASSERT_MASTER_FINISH_MIGRATION)) {
1828	mlog(0, "%s:%.*s: got unrelated assert"
1829	" from %u for migration, ignoring\n",
1830	dlm->name, namelen, name,
1831	assert->node_idx);
1832	__dlm_put_mle(mle);
1833	spin_unlock(lock: &dlm->master_lock);
1834	spin_unlock(lock: &dlm->spinlock);
1835	goto done;
1836	}
1837	}
1838	}
1839	spin_unlock(lock: &dlm->master_lock);
1840
1841	/* ok everything checks out with the MLE
1842	* now check to see if there is a lockres */
1843	res = __dlm_lookup_lockres(dlm, name, len: namelen, hash);
1844	if (res) {
1845	spin_lock(lock: &res->spinlock);
1846	if (res->state & DLM_LOCK_RES_RECOVERING) {
1847	mlog(ML_ERROR, "%u asserting but %.*s is "
1848	"RECOVERING!\n", assert->node_idx, namelen, name);
1849	goto kill;
1850	}
1851	if (!mle) {
1852	if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN &&
1853	res->owner != assert->node_idx) {
1854	mlog(ML_ERROR, "DIE! Mastery assert from %u, "
1855	"but current owner is %u! (%.*s)\n",
1856	assert->node_idx, res->owner, namelen,
1857	name);
1858	__dlm_print_one_lock_resource(res);
1859	BUG();
1860	}
1861	} else if (mle->type != DLM_MLE_MIGRATION) {
1862	if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1863	/* owner is just re-asserting */
1864	if (res->owner == assert->node_idx) {
1865	mlog(0, "owner %u re-asserting on "
1866	"lock %.*s\n", assert->node_idx,
1867	namelen, name);
1868	goto ok;
1869	}
1870	mlog(ML_ERROR, "got assert_master from "
1871	"node %u, but %u is the owner! "
1872	"(%.*s)\n", assert->node_idx,
1873	res->owner, namelen, name);
1874	goto kill;
1875	}
1876	if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
1877	mlog(ML_ERROR, "got assert from %u, but lock "
1878	"with no owner should be "
1879	"in-progress! (%.*s)\n",
1880	assert->node_idx,
1881	namelen, name);
1882	goto kill;
1883	}
1884	} else /* mle->type == DLM_MLE_MIGRATION */ {
1885	/* should only be getting an assert from new master */
1886	if (assert->node_idx != mle->new_master) {
1887	mlog(ML_ERROR, "got assert from %u, but "
1888	"new master is %u, and old master "
1889	"was %u (%.*s)\n",
1890	assert->node_idx, mle->new_master,
1891	mle->master, namelen, name);
1892	goto kill;
1893	}
1894
1895	}
1896	ok:
1897	spin_unlock(lock: &res->spinlock);
1898	}
1899
1900	// mlog(0, "woo! got an assert_master from node %u!\n",
1901	// assert->node_idx);
1902	if (mle) {
1903	int extra_ref = 0;
1904	int nn = -1;
1905	int rr, err = 0;
1906
1907	spin_lock(lock: &mle->spinlock);
1908	if (mle->type == DLM_MLE_BLOCK || mle->type == DLM_MLE_MIGRATION)
1909	extra_ref = 1;
1910	else {
1911	/* MASTER mle: if any bits set in the response map
1912	* then the calling node needs to re-assert to clear
1913	* up nodes that this node contacted */
1914	while ((nn = find_next_bit (addr: mle->response_map, O2NM_MAX_NODES,
1915	offset: nn+1)) < O2NM_MAX_NODES) {
1916	if (nn != dlm->node_num && nn != assert->node_idx) {
1917	master_request = 1;
1918	break;
1919	}
1920	}
1921	}
1922	mle->master = assert->node_idx;
1923	atomic_set(v: &mle->woken, i: 1);
1924	wake_up(&mle->wq);
1925	spin_unlock(lock: &mle->spinlock);
1926
1927	if (res) {
1928	int wake = 0;
1929	spin_lock(lock: &res->spinlock);
1930	if (mle->type == DLM_MLE_MIGRATION) {
1931	mlog(0, "finishing off migration of lockres %.*s, "
1932	"from %u to %u\n",
1933	res->lockname.len, res->lockname.name,
1934	dlm->node_num, mle->new_master);
1935	res->state &= ~DLM_LOCK_RES_MIGRATING;
1936	wake = 1;
1937	dlm_change_lockres_owner(dlm, res, owner: mle->new_master);
1938	BUG_ON(res->state & DLM_LOCK_RES_DIRTY);
1939	} else {
1940	dlm_change_lockres_owner(dlm, res, owner: mle->master);
1941	}
1942	spin_unlock(lock: &res->spinlock);
1943	have_lockres_ref = 1;
1944	if (wake)
1945	wake_up(&res->wq);
1946	}
1947
1948	/* master is known, detach if not already detached.
1949	* ensures that only one assert_master call will happen
1950	* on this mle. */
1951	spin_lock(lock: &dlm->master_lock);
1952
1953	rr = kref_read(kref: &mle->mle_refs);
1954	if (mle->inuse > 0) {
1955	if (extra_ref && rr < 3)
1956	err = 1;
1957	else if (!extra_ref && rr < 2)
1958	err = 1;
1959	} else {
1960	if (extra_ref && rr < 2)
1961	err = 1;
1962	else if (!extra_ref && rr < 1)
1963	err = 1;
1964	}
1965	if (err) {
1966	mlog(ML_ERROR, "%s:%.*s: got assert master from %u "
1967	"that will mess up this node, refs=%d, extra=%d, "
1968	"inuse=%d\n", dlm->name, namelen, name,
1969	assert->node_idx, rr, extra_ref, mle->inuse);
1970	dlm_print_one_mle(mle);
1971	}
1972	__dlm_unlink_mle(dlm, mle);
1973	__dlm_mle_detach_hb_events(dlm, mle);
1974	__dlm_put_mle(mle);
1975	if (extra_ref) {
1976	/* the assert master message now balances the extra
1977	* ref given by the master / migration request message.
1978	* if this is the last put, it will be removed
1979	* from the list. */
1980	__dlm_put_mle(mle);
1981	}
1982	spin_unlock(lock: &dlm->master_lock);
1983	} else if (res) {
1984	if (res->owner != assert->node_idx) {
1985	mlog(0, "assert_master from %u, but current "
1986	"owner is %u (%.*s), no mle\n", assert->node_idx,
1987	res->owner, namelen, name);
1988	}
1989	}
1990	spin_unlock(lock: &dlm->spinlock);
1991
1992	done:
1993	ret = 0;
1994	if (res) {
1995	spin_lock(lock: &res->spinlock);
1996	res->state |= DLM_LOCK_RES_SETREF_INPROG;
1997	spin_unlock(lock: &res->spinlock);
1998	*ret_data = (void *)res;
1999	}
2000	dlm_put(dlm);
2001	if (master_request) {
2002	mlog(0, "need to tell master to reassert\n");
2003	/* positive. negative would shoot down the node. */
2004	ret |= DLM_ASSERT_RESPONSE_REASSERT;
2005	if (!have_lockres_ref) {
2006	mlog(ML_ERROR, "strange, got assert from %u, MASTER "
2007	"mle present here for %s:%.*s, but no lockres!\n",
2008	assert->node_idx, dlm->name, namelen, name);
2009	}
2010	}
2011	if (have_lockres_ref) {
2012	/* let the master know we have a reference to the lockres */
2013	ret |= DLM_ASSERT_RESPONSE_MASTERY_REF;
2014	mlog(0, "%s:%.*s: got assert from %u, need a ref\n",
2015	dlm->name, namelen, name, assert->node_idx);
2016	}
2017	return ret;
2018
2019	kill:
2020	/* kill the caller! */
2021	mlog(ML_ERROR, "Bad message received from another node. Dumping state "
2022	"and killing the other node now! This node is OK and can continue.\n");
2023	__dlm_print_one_lock_resource(res);
2024	spin_unlock(lock: &res->spinlock);
2025	spin_lock(lock: &dlm->master_lock);
2026	if (mle)
2027	__dlm_put_mle(mle);
2028	spin_unlock(lock: &dlm->master_lock);
2029	spin_unlock(lock: &dlm->spinlock);
2030	*ret_data = (void *)res;
2031	dlm_put(dlm);
2032	return -EINVAL;
2033	}
2034
2035	void dlm_assert_master_post_handler(int status, void *data, void *ret_data)
2036	{
2037	struct dlm_lock_resource *res = (struct dlm_lock_resource *)ret_data;
2038
2039	if (ret_data) {
2040	spin_lock(lock: &res->spinlock);
2041	res->state &= ~DLM_LOCK_RES_SETREF_INPROG;
2042	spin_unlock(lock: &res->spinlock);
2043	wake_up(&res->wq);
2044	dlm_lockres_put(res);
2045	}
2046	return;
2047	}
2048
2049	int dlm_dispatch_assert_master(struct dlm_ctxt *dlm,
2050	struct dlm_lock_resource *res,
2051	int ignore_higher, u8 request_from, u32 flags)
2052	{
2053	struct dlm_work_item *item;
2054	item = kzalloc(size: sizeof(*item), GFP_ATOMIC);
2055	if (!item)
2056	return -ENOMEM;
2057
2058
2059	/* queue up work for dlm_assert_master_worker */
2060	dlm_init_work_item(dlm, i: item, f: dlm_assert_master_worker, NULL);
2061	item->u.am.lockres = res; /* already have a ref */
2062	/* can optionally ignore node numbers higher than this node */
2063	item->u.am.ignore_higher = ignore_higher;
2064	item->u.am.request_from = request_from;
2065	item->u.am.flags = flags;
2066
2067	if (ignore_higher)
2068	mlog(0, "IGNORE HIGHER: %.*s\n", res->lockname.len,
2069	res->lockname.name);
2070
2071	spin_lock(lock: &dlm->work_lock);
2072	list_add_tail(new: &item->list, head: &dlm->work_list);
2073	spin_unlock(lock: &dlm->work_lock);
2074
2075	queue_work(wq: dlm->dlm_worker, work: &dlm->dispatched_work);
2076	return 0;
2077	}
2078
2079	static void dlm_assert_master_worker(struct dlm_work_item *item, void *data)
2080	{
2081	struct dlm_ctxt *dlm = data;
2082	int ret = 0;
2083	struct dlm_lock_resource *res;
2084	unsigned long nodemap[BITS_TO_LONGS(O2NM_MAX_NODES)];
2085	int ignore_higher;
2086	int bit;
2087	u8 request_from;
2088	u32 flags;
2089
2090	dlm = item->dlm;
2091	res = item->u.am.lockres;
2092	ignore_higher = item->u.am.ignore_higher;
2093	request_from = item->u.am.request_from;
2094	flags = item->u.am.flags;
2095
2096	spin_lock(lock: &dlm->spinlock);
2097	bitmap_copy(dst: nodemap, src: dlm->domain_map, O2NM_MAX_NODES);
2098	spin_unlock(lock: &dlm->spinlock);
2099
2100	clear_bit(nr: dlm->node_num, addr: nodemap);
2101	if (ignore_higher) {
2102	/* if is this just to clear up mles for nodes below
2103	* this node, do not send the message to the original
2104	* caller or any node number higher than this */
2105	clear_bit(nr: request_from, addr: nodemap);
2106	bit = dlm->node_num;
2107	while (1) {
2108	bit = find_next_bit(addr: nodemap, O2NM_MAX_NODES,
2109	offset: bit+1);
2110	if (bit >= O2NM_MAX_NODES)
2111	break;
2112	clear_bit(nr: bit, addr: nodemap);
2113	}
2114	}
2115
2116	/*
2117	* If we're migrating this lock to someone else, we are no
2118	* longer allowed to assert out own mastery. OTOH, we need to
2119	* prevent migration from starting while we're still asserting
2120	* our dominance. The reserved ast delays migration.
2121	*/
2122	spin_lock(lock: &res->spinlock);
2123	if (res->state & DLM_LOCK_RES_MIGRATING) {
2124	mlog(0, "Someone asked us to assert mastery, but we're "
2125	"in the middle of migration. Skipping assert, "
2126	"the new master will handle that.\n");
2127	spin_unlock(lock: &res->spinlock);
2128	goto put;
2129	} else
2130	__dlm_lockres_reserve_ast(res);
2131	spin_unlock(lock: &res->spinlock);
2132
2133	/* this call now finishes out the nodemap
2134	* even if one or more nodes die */
2135	mlog(0, "worker about to master %.*s here, this=%u\n",
2136	res->lockname.len, res->lockname.name, dlm->node_num);
2137	ret = dlm_do_assert_master(dlm, res, nodemap, flags);
2138	if (ret < 0) {
2139	/* no need to restart, we are done */
2140	if (!dlm_is_host_down(errno: ret))
2141	mlog_errno(ret);
2142	}
2143
2144	/* Ok, we've asserted ourselves. Let's let migration start. */
2145	dlm_lockres_release_ast(dlm, res);
2146
2147	put:
2148	dlm_lockres_drop_inflight_worker(dlm, res);
2149
2150	dlm_lockres_put(res);
2151
2152	mlog(0, "finished with dlm_assert_master_worker\n");
2153	}
2154
2155	/* SPECIAL CASE for the $RECOVERY lock used by the recovery thread.
2156	* We cannot wait for node recovery to complete to begin mastering this
2157	* lockres because this lockres is used to kick off recovery! ;-)
2158	* So, do a pre-check on all living nodes to see if any of those nodes
2159	* think that $RECOVERY is currently mastered by a dead node. If so,
2160	* we wait a short time to allow that node to get notified by its own
2161	* heartbeat stack, then check again. All $RECOVERY lock resources
2162	* mastered by dead nodes are purged when the heartbeat callback is
2163	* fired, so we can know for sure that it is safe to continue once
2164	* the node returns a live node or no node. */
2165	static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
2166	struct dlm_lock_resource *res)
2167	{
2168	struct dlm_node_iter iter;
2169	int nodenum;
2170	int ret = 0;
2171	u8 master = DLM_LOCK_RES_OWNER_UNKNOWN;
2172
2173	spin_lock(lock: &dlm->spinlock);
2174	dlm_node_iter_init(map: dlm->domain_map, iter: &iter);
2175	spin_unlock(lock: &dlm->spinlock);
2176
2177	while ((nodenum = dlm_node_iter_next(iter: &iter)) >= 0) {
2178	/* do not send to self */
2179	if (nodenum == dlm->node_num)
2180	continue;
2181	ret = dlm_do_master_requery(dlm, res, nodenum, real_master: &master);
2182	if (ret < 0) {
2183	mlog_errno(ret);
2184	if (!dlm_is_host_down(errno: ret))
2185	BUG();
2186	/* host is down, so answer for that node would be
2187	* DLM_LOCK_RES_OWNER_UNKNOWN. continue. */
2188	ret = 0;
2189	}
2190
2191	if (master != DLM_LOCK_RES_OWNER_UNKNOWN) {
2192	/* check to see if this master is in the recovery map */
2193	spin_lock(lock: &dlm->spinlock);
2194	if (test_bit(master, dlm->recovery_map)) {
2195	mlog(ML_NOTICE, "%s: node %u has not seen "
2196	"node %u go down yet, and thinks the "
2197	"dead node is mastering the recovery "
2198	"lock. must wait.\n", dlm->name,
2199	nodenum, master);
2200	ret = -EAGAIN;
2201	}
2202	spin_unlock(lock: &dlm->spinlock);
2203	mlog(0, "%s: reco lock master is %u\n", dlm->name,
2204	master);
2205	break;
2206	}
2207	}
2208	return ret;
2209	}
2210
2211	/*
2212	* DLM_DEREF_LOCKRES_MSG
2213	*/
2214
2215	int dlm_drop_lockres_ref(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
2216	{
2217	struct dlm_deref_lockres deref;
2218	int ret = 0, r;
2219	const char *lockname;
2220	unsigned int namelen;
2221
2222	lockname = res->lockname.name;
2223	namelen = res->lockname.len;
2224	BUG_ON(namelen > O2NM_MAX_NAME_LEN);
2225
2226	memset(&deref, 0, sizeof(deref));
2227	deref.node_idx = dlm->node_num;
2228	deref.namelen = namelen;
2229	memcpy(deref.name, lockname, namelen);
2230
2231	ret = o2net_send_message(msg_type: DLM_DEREF_LOCKRES_MSG, key: dlm->key,
2232	data: &deref, len: sizeof(deref), target_node: res->owner, status: &r);
2233	if (ret < 0)
2234	mlog(ML_ERROR, "%s: res %.*s, error %d send DEREF to node %u\n",
2235	dlm->name, namelen, lockname, ret, res->owner);
2236	else if (r < 0) {
2237	/* BAD. other node says I did not have a ref. */
2238	mlog(ML_ERROR, "%s: res %.*s, DEREF to node %u got %d\n",
2239	dlm->name, namelen, lockname, res->owner, r);
2240	dlm_print_one_lock_resource(res);
2241	if (r == -ENOMEM)
2242	BUG();
2243	} else
2244	ret = r;
2245
2246	return ret;
2247	}
2248
2249	int dlm_deref_lockres_handler(struct o2net_msg *msg, u32 len, void *data,
2250	void **ret_data)
2251	{
2252	struct dlm_ctxt *dlm = data;
2253	struct dlm_deref_lockres *deref = (struct dlm_deref_lockres *)msg->buf;
2254	struct dlm_lock_resource *res = NULL;
2255	char *name;
2256	unsigned int namelen;
2257	int ret = -EINVAL;
2258	u8 node;
2259	unsigned int hash;
2260	struct dlm_work_item *item;
2261	int cleared = 0;
2262	int dispatch = 0;
2263
2264	if (!dlm_grab(dlm))
2265	return 0;
2266
2267	name = deref->name;
2268	namelen = deref->namelen;
2269	node = deref->node_idx;
2270
2271	if (namelen > DLM_LOCKID_NAME_MAX) {
2272	mlog(ML_ERROR, "Invalid name length!");
2273	goto done;
2274	}
2275	if (deref->node_idx >= O2NM_MAX_NODES) {
2276	mlog(ML_ERROR, "Invalid node number: %u\n", node);
2277	goto done;
2278	}
2279
2280	hash = dlm_lockid_hash(name, namelen);
2281
2282	spin_lock(lock: &dlm->spinlock);
2283	res = __dlm_lookup_lockres_full(dlm, name, len: namelen, hash);
2284	if (!res) {
2285	spin_unlock(lock: &dlm->spinlock);
2286	mlog(ML_ERROR, "%s:%.*s: bad lockres name\n",
2287	dlm->name, namelen, name);
2288	goto done;
2289	}
2290	spin_unlock(lock: &dlm->spinlock);
2291
2292	spin_lock(lock: &res->spinlock);
2293	if (res->state & DLM_LOCK_RES_SETREF_INPROG)
2294	dispatch = 1;
2295	else {
2296	BUG_ON(res->state & DLM_LOCK_RES_DROPPING_REF);
2297	if (test_bit(node, res->refmap)) {
2298	dlm_lockres_clear_refmap_bit(dlm, res, bit: node);
2299	cleared = 1;
2300	}
2301	}
2302	spin_unlock(lock: &res->spinlock);
2303
2304	if (!dispatch) {
2305	if (cleared)
2306	dlm_lockres_calc_usage(dlm, res);
2307	else {
2308	mlog(ML_ERROR, "%s:%.*s: node %u trying to drop ref "
2309	"but it is already dropped!\n", dlm->name,
2310	res->lockname.len, res->lockname.name, node);
2311	dlm_print_one_lock_resource(res);
2312	}
2313	ret = DLM_DEREF_RESPONSE_DONE;
2314	goto done;
2315	}
2316
2317	item = kzalloc(size: sizeof(*item), GFP_NOFS);
2318	if (!item) {
2319	ret = -ENOMEM;
2320	mlog_errno(ret);
2321	goto done;
2322	}
2323
2324	dlm_init_work_item(dlm, i: item, f: dlm_deref_lockres_worker, NULL);
2325	item->u.dl.deref_res = res;
2326	item->u.dl.deref_node = node;
2327
2328	spin_lock(lock: &dlm->work_lock);
2329	list_add_tail(new: &item->list, head: &dlm->work_list);
2330	spin_unlock(lock: &dlm->work_lock);
2331
2332	queue_work(wq: dlm->dlm_worker, work: &dlm->dispatched_work);
2333	return DLM_DEREF_RESPONSE_INPROG;
2334
2335	done:
2336	if (res)
2337	dlm_lockres_put(res);
2338	dlm_put(dlm);
2339
2340	return ret;
2341	}
2342
2343	int dlm_deref_lockres_done_handler(struct o2net_msg *msg, u32 len, void *data,
2344	void **ret_data)
2345	{
2346	struct dlm_ctxt *dlm = data;
2347	struct dlm_deref_lockres_done *deref
2348	= (struct dlm_deref_lockres_done *)msg->buf;
2349	struct dlm_lock_resource *res = NULL;
2350	char *name;
2351	unsigned int namelen;
2352	int ret = -EINVAL;
2353	u8 node;
2354	unsigned int hash;
2355
2356	if (!dlm_grab(dlm))
2357	return 0;
2358
2359	name = deref->name;
2360	namelen = deref->namelen;
2361	node = deref->node_idx;
2362
2363	if (namelen > DLM_LOCKID_NAME_MAX) {
2364	mlog(ML_ERROR, "Invalid name length!");
2365	goto done;
2366	}
2367	if (deref->node_idx >= O2NM_MAX_NODES) {
2368	mlog(ML_ERROR, "Invalid node number: %u\n", node);
2369	goto done;
2370	}
2371
2372	hash = dlm_lockid_hash(name, namelen);
2373
2374	spin_lock(lock: &dlm->spinlock);
2375	res = __dlm_lookup_lockres_full(dlm, name, len: namelen, hash);
2376	if (!res) {
2377	spin_unlock(lock: &dlm->spinlock);
2378	mlog(ML_ERROR, "%s:%.*s: bad lockres name\n",
2379	dlm->name, namelen, name);
2380	goto done;
2381	}
2382
2383	spin_lock(lock: &res->spinlock);
2384	if (!(res->state & DLM_LOCK_RES_DROPPING_REF)) {
2385	spin_unlock(lock: &res->spinlock);
2386	spin_unlock(lock: &dlm->spinlock);
2387	mlog(ML_NOTICE, "%s:%.*s: node %u sends deref done "
2388	"but it is already derefed!\n", dlm->name,
2389	res->lockname.len, res->lockname.name, node);
2390	ret = 0;
2391	goto done;
2392	}
2393
2394	__dlm_do_purge_lockres(dlm, res);
2395	spin_unlock(lock: &res->spinlock);
2396	wake_up(&res->wq);
2397
2398	spin_unlock(lock: &dlm->spinlock);
2399
2400	ret = 0;
2401	done:
2402	if (res)
2403	dlm_lockres_put(res);
2404	dlm_put(dlm);
2405	return ret;
2406	}
2407
2408	static void dlm_drop_lockres_ref_done(struct dlm_ctxt *dlm,
2409	struct dlm_lock_resource *res, u8 node)
2410	{
2411	struct dlm_deref_lockres_done deref;
2412	int ret = 0, r;
2413	const char *lockname;
2414	unsigned int namelen;
2415
2416	lockname = res->lockname.name;
2417	namelen = res->lockname.len;
2418	BUG_ON(namelen > O2NM_MAX_NAME_LEN);
2419
2420	memset(&deref, 0, sizeof(deref));
2421	deref.node_idx = dlm->node_num;
2422	deref.namelen = namelen;
2423	memcpy(deref.name, lockname, namelen);
2424
2425	ret = o2net_send_message(msg_type: DLM_DEREF_LOCKRES_DONE, key: dlm->key,
2426	data: &deref, len: sizeof(deref), target_node: node, status: &r);
2427	if (ret < 0) {
2428	mlog(ML_ERROR, "%s: res %.*s, error %d send DEREF DONE "
2429	" to node %u\n", dlm->name, namelen,
2430	lockname, ret, node);
2431	} else if (r < 0) {
2432	/* ignore the error */
2433	mlog(ML_ERROR, "%s: res %.*s, DEREF to node %u got %d\n",
2434	dlm->name, namelen, lockname, node, r);
2435	dlm_print_one_lock_resource(res);
2436	}
2437	}
2438
2439	static void dlm_deref_lockres_worker(struct dlm_work_item *item, void *data)
2440	{
2441	struct dlm_ctxt *dlm;
2442	struct dlm_lock_resource *res;
2443	u8 node;
2444	u8 cleared = 0;
2445
2446	dlm = item->dlm;
2447	res = item->u.dl.deref_res;
2448	node = item->u.dl.deref_node;
2449
2450	spin_lock(lock: &res->spinlock);
2451	BUG_ON(res->state & DLM_LOCK_RES_DROPPING_REF);
2452	__dlm_wait_on_lockres_flags(res, DLM_LOCK_RES_SETREF_INPROG);
2453	if (test_bit(node, res->refmap)) {
2454	dlm_lockres_clear_refmap_bit(dlm, res, bit: node);
2455	cleared = 1;
2456	}
2457	spin_unlock(lock: &res->spinlock);
2458
2459	dlm_drop_lockres_ref_done(dlm, res, node);
2460
2461	if (cleared) {
2462	mlog(0, "%s:%.*s node %u ref dropped in dispatch\n",
2463	dlm->name, res->lockname.len, res->lockname.name, node);
2464	dlm_lockres_calc_usage(dlm, res);
2465	} else {
2466	mlog(ML_ERROR, "%s:%.*s: node %u trying to drop ref "
2467	"but it is already dropped!\n", dlm->name,
2468	res->lockname.len, res->lockname.name, node);
2469	dlm_print_one_lock_resource(res);
2470	}
2471
2472	dlm_lockres_put(res);
2473	}
2474
2475	/*
2476	* A migratable resource is one that is :
2477	* 1. locally mastered, and,
2478	* 2. zero local locks, and,
2479	* 3. one or more non-local locks, or, one or more references
2480	* Returns 1 if yes, 0 if not.
2481	*/
2482	static int dlm_is_lockres_migratable(struct dlm_ctxt *dlm,
2483	struct dlm_lock_resource *res)
2484	{
2485	enum dlm_lockres_list idx;
2486	int nonlocal = 0, node_ref;
2487	struct list_head *queue;
2488	struct dlm_lock *lock;
2489	u64 cookie;
2490
2491	assert_spin_locked(&res->spinlock);
2492
2493	/* delay migration when the lockres is in MIGRATING state */
2494	if (res->state & DLM_LOCK_RES_MIGRATING)
2495	return 0;
2496
2497	/* delay migration when the lockres is in RECOCERING state */
2498	if (res->state & (DLM_LOCK_RES_RECOVERING|
2499	DLM_LOCK_RES_RECOVERY_WAITING))
2500	return 0;
2501
2502	if (res->owner != dlm->node_num)
2503	return 0;
2504
2505	for (idx = DLM_GRANTED_LIST; idx <= DLM_BLOCKED_LIST; idx++) {
2506	queue = dlm_list_idx_to_ptr(res, idx);
2507	list_for_each_entry(lock, queue, list) {
2508	if (lock->ml.node != dlm->node_num) {
2509	nonlocal++;
2510	continue;
2511	}
2512	cookie = be64_to_cpu(lock->ml.cookie);
2513	mlog(0, "%s: Not migratable res %.*s, lock %u:%llu on "
2514	"%s list\n", dlm->name, res->lockname.len,
2515	res->lockname.name,
2516	dlm_get_lock_cookie_node(cookie),
2517	dlm_get_lock_cookie_seq(cookie),
2518	dlm_list_in_text(idx));
2519	return 0;
2520	}
2521	}
2522
2523	if (!nonlocal) {
2524	node_ref = find_first_bit(addr: res->refmap, O2NM_MAX_NODES);
2525	if (node_ref >= O2NM_MAX_NODES)
2526	return 0;
2527	}
2528
2529	mlog(0, "%s: res %.*s, Migratable\n", dlm->name, res->lockname.len,
2530	res->lockname.name);
2531
2532	return 1;
2533	}
2534
2535	/*
2536	* DLM_MIGRATE_LOCKRES
2537	*/
2538
2539
2540	static int dlm_migrate_lockres(struct dlm_ctxt *dlm,
2541	struct dlm_lock_resource *res, u8 target)
2542	{
2543	struct dlm_master_list_entry *mle = NULL;
2544	struct dlm_master_list_entry *oldmle = NULL;
2545	struct dlm_migratable_lockres *mres = NULL;
2546	int ret = 0;
2547	const char *name;
2548	unsigned int namelen;
2549	int mle_added = 0;
2550	int wake = 0;
2551
2552	if (!dlm_grab(dlm))
2553	return -EINVAL;
2554
2555	name = res->lockname.name;
2556	namelen = res->lockname.len;
2557
2558	mlog(0, "%s: Migrating %.*s to node %u\n", dlm->name, namelen, name,
2559	target);
2560
2561	/* preallocate up front. if this fails, abort */
2562	ret = -ENOMEM;
2563	mres = (struct dlm_migratable_lockres *) __get_free_page(GFP_NOFS);
2564	if (!mres) {
2565	mlog_errno(ret);
2566	goto leave;
2567	}
2568
2569	mle = kmem_cache_alloc(cachep: dlm_mle_cache, GFP_NOFS);
2570	if (!mle) {
2571	mlog_errno(ret);
2572	goto leave;
2573	}
2574	ret = 0;
2575
2576	/*
2577	* clear any existing master requests and
2578	* add the migration mle to the list
2579	*/
2580	spin_lock(lock: &dlm->spinlock);
2581	spin_lock(lock: &dlm->master_lock);
2582	ret = dlm_add_migration_mle(dlm, res, mle, oldmle: &oldmle, name,
2583	namelen, new_master: target, master: dlm->node_num);
2584	/* get an extra reference on the mle.
2585	* otherwise the assert_master from the new
2586	* master will destroy this.
2587	*/
2588	if (ret != -EEXIST)
2589	dlm_get_mle_inuse(mle);
2590
2591	spin_unlock(lock: &dlm->master_lock);
2592	spin_unlock(lock: &dlm->spinlock);
2593
2594	if (ret == -EEXIST) {
2595	mlog(0, "another process is already migrating it\n");
2596	goto fail;
2597	}
2598	mle_added = 1;
2599
2600	/*
2601	* set the MIGRATING flag and flush asts
2602	* if we fail after this we need to re-dirty the lockres
2603	*/
2604	if (dlm_mark_lockres_migrating(dlm, res, target) < 0) {
2605	mlog(ML_ERROR, "tried to migrate %.*s to %u, but "
2606	"the target went down.\n", res->lockname.len,
2607	res->lockname.name, target);
2608	spin_lock(lock: &res->spinlock);
2609	res->state &= ~DLM_LOCK_RES_MIGRATING;
2610	wake = 1;
2611	spin_unlock(lock: &res->spinlock);
2612	ret = -EINVAL;
2613	}
2614
2615	fail:
2616	if (ret != -EEXIST && oldmle) {
2617	/* master is known, detach if not already detached */
2618	dlm_mle_detach_hb_events(dlm, mle: oldmle);
2619	dlm_put_mle(mle: oldmle);
2620	}
2621
2622	if (ret < 0) {
2623	if (mle_added) {
2624	dlm_mle_detach_hb_events(dlm, mle);
2625	dlm_put_mle(mle);
2626	dlm_put_mle_inuse(mle);
2627	} else if (mle) {
2628	kmem_cache_free(s: dlm_mle_cache, objp: mle);
2629	mle = NULL;
2630	}
2631	goto leave;
2632	}
2633
2634	/*
2635	* at this point, we have a migration target, an mle
2636	* in the master list, and the MIGRATING flag set on
2637	* the lockres
2638	*/
2639
2640	/* now that remote nodes are spinning on the MIGRATING flag,
2641	* ensure that all assert_master work is flushed. */
2642	flush_workqueue(dlm->dlm_worker);
2643
2644	/* notify new node and send all lock state */
2645	/* call send_one_lockres with migration flag.
2646	* this serves as notice to the target node that a
2647	* migration is starting. */
2648	ret = dlm_send_one_lockres(dlm, res, mres, send_to: target,
2649	DLM_MRES_MIGRATION);
2650
2651	if (ret < 0) {
2652	mlog(0, "migration to node %u failed with %d\n",
2653	target, ret);
2654	/* migration failed, detach and clean up mle */
2655	dlm_mle_detach_hb_events(dlm, mle);
2656	dlm_put_mle(mle);
2657	dlm_put_mle_inuse(mle);
2658	spin_lock(lock: &res->spinlock);
2659	res->state &= ~DLM_LOCK_RES_MIGRATING;
2660	wake = 1;
2661	spin_unlock(lock: &res->spinlock);
2662	if (dlm_is_host_down(errno: ret))
2663	dlm_wait_for_node_death(dlm, node: target,
2664	DLM_NODE_DEATH_WAIT_MAX);
2665	goto leave;
2666	}
2667
2668	/* at this point, the target sends a message to all nodes,
2669	* (using dlm_do_migrate_request). this node is skipped since
2670	* we had to put an mle in the list to begin the process. this
2671	* node now waits for target to do an assert master. this node
2672	* will be the last one notified, ensuring that the migration
2673	* is complete everywhere. if the target dies while this is
2674	* going on, some nodes could potentially see the target as the
2675	* master, so it is important that my recovery finds the migration
2676	* mle and sets the master to UNKNOWN. */
2677
2678
2679	/* wait for new node to assert master */
2680	while (1) {
2681	ret = wait_event_interruptible_timeout(mle->wq,
2682	(atomic_read(&mle->woken) == 1),
2683	msecs_to_jiffies(5000));
2684
2685	if (ret >= 0) {
2686	if (atomic_read(v: &mle->woken) == 1 ||
2687	res->owner == target)
2688	break;
2689
2690	mlog(0, "%s:%.*s: timed out during migration\n",
2691	dlm->name, res->lockname.len, res->lockname.name);
2692	/* avoid hang during shutdown when migrating lockres
2693	* to a node which also goes down */
2694	if (dlm_is_node_dead(dlm, node: target)) {
2695	mlog(0, "%s:%.*s: expected migration "
2696	"target %u is no longer up, restarting\n",
2697	dlm->name, res->lockname.len,
2698	res->lockname.name, target);
2699	ret = -EINVAL;
2700	/* migration failed, detach and clean up mle */
2701	dlm_mle_detach_hb_events(dlm, mle);
2702	dlm_put_mle(mle);
2703	dlm_put_mle_inuse(mle);
2704	spin_lock(lock: &res->spinlock);
2705	res->state &= ~DLM_LOCK_RES_MIGRATING;
2706	wake = 1;
2707	spin_unlock(lock: &res->spinlock);
2708	goto leave;
2709	}
2710	} else
2711	mlog(0, "%s:%.*s: caught signal during migration\n",
2712	dlm->name, res->lockname.len, res->lockname.name);
2713	}
2714
2715	/* all done, set the owner, clear the flag */
2716	spin_lock(lock: &res->spinlock);
2717	dlm_set_lockres_owner(dlm, res, owner: target);
2718	res->state &= ~DLM_LOCK_RES_MIGRATING;
2719	dlm_remove_nonlocal_locks(dlm, res);
2720	spin_unlock(lock: &res->spinlock);
2721	wake_up(&res->wq);
2722
2723	/* master is known, detach if not already detached */
2724	dlm_mle_detach_hb_events(dlm, mle);
2725	dlm_put_mle_inuse(mle);
2726	ret = 0;
2727
2728	dlm_lockres_calc_usage(dlm, res);
2729
2730	leave:
2731	/* re-dirty the lockres if we failed */
2732	if (ret < 0)
2733	dlm_kick_thread(dlm, res);
2734
2735	/* wake up waiters if the MIGRATING flag got set
2736	* but migration failed */
2737	if (wake)
2738	wake_up(&res->wq);
2739
2740	if (mres)
2741	free_page((unsigned long)mres);
2742
2743	dlm_put(dlm);
2744
2745	mlog(0, "%s: Migrating %.*s to %u, returns %d\n", dlm->name, namelen,
2746	name, target, ret);
2747	return ret;
2748	}
2749
2750	/*
2751	* Should be called only after beginning the domain leave process.
2752	* There should not be any remaining locks on nonlocal lock resources,
2753	* and there should be no local locks left on locally mastered resources.
2754	*
2755	* Called with the dlm spinlock held, may drop it to do migration, but
2756	* will re-acquire before exit.
2757	*
2758	* Returns: 1 if dlm->spinlock was dropped/retaken, 0 if never dropped
2759	*/
2760	int dlm_empty_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
2761	__must_hold(&dlm->spinlock)
2762	{
2763	int ret;
2764	int lock_dropped = 0;
2765	u8 target = O2NM_MAX_NODES;
2766
2767	assert_spin_locked(&dlm->spinlock);
2768
2769	spin_lock(lock: &res->spinlock);
2770	if (dlm_is_lockres_migratable(dlm, res))
2771	target = dlm_pick_migration_target(dlm, res);
2772	spin_unlock(lock: &res->spinlock);
2773
2774	if (target == O2NM_MAX_NODES)
2775	goto leave;
2776
2777	/* Wheee! Migrate lockres here! Will sleep so drop spinlock. */
2778	spin_unlock(lock: &dlm->spinlock);
2779	lock_dropped = 1;
2780	ret = dlm_migrate_lockres(dlm, res, target);
2781	if (ret)
2782	mlog(0, "%s: res %.*s, Migrate to node %u failed with %d\n",
2783	dlm->name, res->lockname.len, res->lockname.name,
2784	target, ret);
2785	spin_lock(lock: &dlm->spinlock);
2786	leave:
2787	return lock_dropped;
2788	}
2789
2790	int dlm_lock_basts_flushed(struct dlm_ctxt *dlm, struct dlm_lock *lock)
2791	{
2792	int ret;
2793	spin_lock(lock: &dlm->ast_lock);
2794	spin_lock(lock: &lock->spinlock);
2795	ret = (list_empty(head: &lock->bast_list) && !lock->bast_pending);
2796	spin_unlock(lock: &lock->spinlock);
2797	spin_unlock(lock: &dlm->ast_lock);
2798	return ret;
2799	}
2800
2801	static int dlm_migration_can_proceed(struct dlm_ctxt *dlm,
2802	struct dlm_lock_resource *res,
2803	u8 mig_target)
2804	{
2805	int can_proceed;
2806	spin_lock(lock: &res->spinlock);
2807	can_proceed = !!(res->state & DLM_LOCK_RES_MIGRATING);
2808	spin_unlock(lock: &res->spinlock);
2809
2810	/* target has died, so make the caller break out of the
2811	* wait_event, but caller must recheck the domain_map */
2812	spin_lock(lock: &dlm->spinlock);
2813	if (!test_bit(mig_target, dlm->domain_map))
2814	can_proceed = 1;
2815	spin_unlock(lock: &dlm->spinlock);
2816	return can_proceed;
2817	}
2818
2819	static int dlm_lockres_is_dirty(struct dlm_ctxt *dlm,
2820	struct dlm_lock_resource *res)
2821	{
2822	int ret;
2823	spin_lock(lock: &res->spinlock);
2824	ret = !!(res->state & DLM_LOCK_RES_DIRTY);
2825	spin_unlock(lock: &res->spinlock);
2826	return ret;
2827	}
2828
2829
2830	static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
2831	struct dlm_lock_resource *res,
2832	u8 target)
2833	{
2834	int ret = 0;
2835
2836	mlog(0, "dlm_mark_lockres_migrating: %.*s, from %u to %u\n",
2837	res->lockname.len, res->lockname.name, dlm->node_num,
2838	target);
2839	/* need to set MIGRATING flag on lockres. this is done by
2840	* ensuring that all asts have been flushed for this lockres. */
2841	spin_lock(lock: &res->spinlock);
2842	BUG_ON(res->migration_pending);
2843	res->migration_pending = 1;
2844	/* strategy is to reserve an extra ast then release
2845	* it below, letting the release do all of the work */
2846	__dlm_lockres_reserve_ast(res);
2847	spin_unlock(lock: &res->spinlock);
2848
2849	/* now flush all the pending asts */
2850	dlm_kick_thread(dlm, res);
2851	/* before waiting on DIRTY, block processes which may
2852	* try to dirty the lockres before MIGRATING is set */
2853	spin_lock(lock: &res->spinlock);
2854	BUG_ON(res->state & DLM_LOCK_RES_BLOCK_DIRTY);
2855	res->state |= DLM_LOCK_RES_BLOCK_DIRTY;
2856	spin_unlock(lock: &res->spinlock);
2857	/* now wait on any pending asts and the DIRTY state */
2858	wait_event(dlm->ast_wq, !dlm_lockres_is_dirty(dlm, res));
2859	dlm_lockres_release_ast(dlm, res);
2860
2861	mlog(0, "about to wait on migration_wq, dirty=%s\n",
2862	res->state & DLM_LOCK_RES_DIRTY ? "yes" : "no");
2863	/* if the extra ref we just put was the final one, this
2864	* will pass thru immediately. otherwise, we need to wait
2865	* for the last ast to finish. */
2866	again:
2867	ret = wait_event_interruptible_timeout(dlm->migration_wq,
2868	dlm_migration_can_proceed(dlm, res, target),
2869	msecs_to_jiffies(1000));
2870	if (ret < 0) {
2871	mlog(0, "woken again: migrating? %s, dead? %s\n",
2872	res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
2873	test_bit(target, dlm->domain_map) ? "no":"yes");
2874	} else {
2875	mlog(0, "all is well: migrating? %s, dead? %s\n",
2876	res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
2877	test_bit(target, dlm->domain_map) ? "no":"yes");
2878	}
2879	if (!dlm_migration_can_proceed(dlm, res, mig_target: target)) {
2880	mlog(0, "trying again...\n");
2881	goto again;
2882	}
2883
2884	ret = 0;
2885	/* did the target go down or die? */
2886	spin_lock(lock: &dlm->spinlock);
2887	if (!test_bit(target, dlm->domain_map)) {
2888	mlog(ML_ERROR, "aha. migration target %u just went down\n",
2889	target);
2890	ret = -EHOSTDOWN;
2891	}
2892	spin_unlock(lock: &dlm->spinlock);
2893
2894	/*
2895	* if target is down, we need to clear DLM_LOCK_RES_BLOCK_DIRTY for
2896	* another try; otherwise, we are sure the MIGRATING state is there,
2897	* drop the unneeded state which blocked threads trying to DIRTY
2898	*/
2899	spin_lock(lock: &res->spinlock);
2900	BUG_ON(!(res->state & DLM_LOCK_RES_BLOCK_DIRTY));
2901	res->state &= ~DLM_LOCK_RES_BLOCK_DIRTY;
2902	if (!ret)
2903	BUG_ON(!(res->state & DLM_LOCK_RES_MIGRATING));
2904	else
2905	res->migration_pending = 0;
2906	spin_unlock(lock: &res->spinlock);
2907
2908	/*
2909	* at this point:
2910	*
2911	* o the DLM_LOCK_RES_MIGRATING flag is set if target not down
2912	* o there are no pending asts on this lockres
2913	* o all processes trying to reserve an ast on this
2914	* lockres must wait for the MIGRATING flag to clear
2915	*/
2916	return ret;
2917	}
2918
2919	/* last step in the migration process.
2920	* original master calls this to free all of the dlm_lock
2921	* structures that used to be for other nodes. */
2922	static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
2923	struct dlm_lock_resource *res)
2924	{
2925	struct list_head *queue = &res->granted;
2926	int i, bit;
2927	struct dlm_lock *lock, *next;
2928
2929	assert_spin_locked(&res->spinlock);
2930
2931	BUG_ON(res->owner == dlm->node_num);
2932
2933	for (i=0; i<3; i++) {
2934	list_for_each_entry_safe(lock, next, queue, list) {
2935	if (lock->ml.node != dlm->node_num) {
2936	mlog(0, "putting lock for node %u\n",
2937	lock->ml.node);
2938	/* be extra careful */
2939	BUG_ON(!list_empty(&lock->ast_list));
2940	BUG_ON(!list_empty(&lock->bast_list));
2941	BUG_ON(lock->ast_pending);
2942	BUG_ON(lock->bast_pending);
2943	dlm_lockres_clear_refmap_bit(dlm, res,
2944	bit: lock->ml.node);
2945	list_del_init(entry: &lock->list);
2946	dlm_lock_put(lock);
2947	/* In a normal unlock, we would have added a
2948	* DLM_UNLOCK_FREE_LOCK action. Force it. */
2949	dlm_lock_put(lock);
2950	}
2951	}
2952	queue++;
2953	}
2954	bit = 0;
2955	while (1) {
2956	bit = find_next_bit(addr: res->refmap, O2NM_MAX_NODES, offset: bit);
2957	if (bit >= O2NM_MAX_NODES)
2958	break;
2959	/* do not clear the local node reference, if there is a
2960	* process holding this, let it drop the ref itself */
2961	if (bit != dlm->node_num) {
2962	mlog(0, "%s:%.*s: node %u had a ref to this "
2963	"migrating lockres, clearing\n", dlm->name,
2964	res->lockname.len, res->lockname.name, bit);
2965	dlm_lockres_clear_refmap_bit(dlm, res, bit);
2966	}
2967	bit++;
2968	}
2969	}
2970
2971	/*
2972	* Pick a node to migrate the lock resource to. This function selects a
2973	* potential target based first on the locks and then on refmap. It skips
2974	* nodes that are in the process of exiting the domain.
2975	*/
2976	static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
2977	struct dlm_lock_resource *res)
2978	{
2979	enum dlm_lockres_list idx;
2980	struct list_head *queue;
2981	struct dlm_lock *lock;
2982	int noderef;
2983	u8 nodenum = O2NM_MAX_NODES;
2984
2985	assert_spin_locked(&dlm->spinlock);
2986	assert_spin_locked(&res->spinlock);
2987
2988	/* Go through all the locks */
2989	for (idx = DLM_GRANTED_LIST; idx <= DLM_BLOCKED_LIST; idx++) {
2990	queue = dlm_list_idx_to_ptr(res, idx);
2991	list_for_each_entry(lock, queue, list) {
2992	if (lock->ml.node == dlm->node_num)
2993	continue;
2994	if (test_bit(lock->ml.node, dlm->exit_domain_map))
2995	continue;
2996	nodenum = lock->ml.node;
2997	goto bail;
2998	}
2999	}
3000
3001	/* Go thru the refmap */
3002	noderef = -1;
3003	while (1) {
3004	noderef = find_next_bit(addr: res->refmap, O2NM_MAX_NODES,
3005	offset: noderef + 1);
3006	if (noderef >= O2NM_MAX_NODES)
3007	break;
3008	if (noderef == dlm->node_num)
3009	continue;
3010	if (test_bit(noderef, dlm->exit_domain_map))
3011	continue;
3012	nodenum = noderef;
3013	goto bail;
3014	}
3015
3016	bail:
3017	return nodenum;
3018	}
3019
3020	/* this is called by the new master once all lockres
3021	* data has been received */
3022	static int dlm_do_migrate_request(struct dlm_ctxt *dlm,
3023	struct dlm_lock_resource *res,
3024	u8 master, u8 new_master,
3025	struct dlm_node_iter *iter)
3026	{
3027	struct dlm_migrate_request migrate;
3028	int ret, skip, status = 0;
3029	int nodenum;
3030
3031	memset(&migrate, 0, sizeof(migrate));
3032	migrate.namelen = res->lockname.len;
3033	memcpy(migrate.name, res->lockname.name, migrate.namelen);
3034	migrate.new_master = new_master;
3035	migrate.master = master;
3036
3037	ret = 0;
3038
3039	/* send message to all nodes, except the master and myself */
3040	while ((nodenum = dlm_node_iter_next(iter)) >= 0) {
3041	if (nodenum == master ||
3042	nodenum == new_master)
3043	continue;
3044
3045	/* We could race exit domain. If exited, skip. */
3046	spin_lock(lock: &dlm->spinlock);
3047	skip = (!test_bit(nodenum, dlm->domain_map));
3048	spin_unlock(lock: &dlm->spinlock);
3049	if (skip) {
3050	clear_bit(nr: nodenum, addr: iter->node_map);
3051	continue;
3052	}
3053
3054	ret = o2net_send_message(msg_type: DLM_MIGRATE_REQUEST_MSG, key: dlm->key,
3055	data: &migrate, len: sizeof(migrate), target_node: nodenum,
3056	status: &status);
3057	if (ret < 0) {
3058	mlog(ML_ERROR, "%s: res %.*s, Error %d send "
3059	"MIGRATE_REQUEST to node %u\n", dlm->name,
3060	migrate.namelen, migrate.name, ret, nodenum);
3061	if (!dlm_is_host_down(errno: ret)) {
3062	mlog(ML_ERROR, "unhandled error=%d!\n", ret);
3063	BUG();
3064	}
3065	clear_bit(nr: nodenum, addr: iter->node_map);
3066	ret = 0;
3067	} else if (status < 0) {
3068	mlog(0, "migrate request (node %u) returned %d!\n",
3069	nodenum, status);
3070	ret = status;
3071	} else if (status == DLM_MIGRATE_RESPONSE_MASTERY_REF) {
3072	/* during the migration request we short-circuited
3073	* the mastery of the lockres. make sure we have
3074	* a mastery ref for nodenum */
3075	mlog(0, "%s:%.*s: need ref for node %u\n",
3076	dlm->name, res->lockname.len, res->lockname.name,
3077	nodenum);
3078	spin_lock(lock: &res->spinlock);
3079	dlm_lockres_set_refmap_bit(dlm, res, bit: nodenum);
3080	spin_unlock(lock: &res->spinlock);
3081	}
3082	}
3083
3084	if (ret < 0)
3085	mlog_errno(ret);
3086
3087	mlog(0, "returning ret=%d\n", ret);
3088	return ret;
3089	}
3090
3091
3092	/* if there is an existing mle for this lockres, we now know who the master is.
3093	* (the one who sent us *this* message) we can clear it up right away.
3094	* since the process that put the mle on the list still has a reference to it,
3095	* we can unhash it now, set the master and wake the process. as a result,
3096	* we will have no mle in the list to start with. now we can add an mle for
3097	* the migration and this should be the only one found for those scanning the
3098	* list. */
3099	int dlm_migrate_request_handler(struct o2net_msg *msg, u32 len, void *data,
3100	void **ret_data)
3101	{
3102	struct dlm_ctxt *dlm = data;
3103	struct dlm_lock_resource *res = NULL;
3104	struct dlm_migrate_request *migrate = (struct dlm_migrate_request *) msg->buf;
3105	struct dlm_master_list_entry *mle = NULL, *oldmle = NULL;
3106	const char *name;
3107	unsigned int namelen, hash;
3108	int ret = 0;
3109
3110	if (!dlm_grab(dlm))
3111	return 0;
3112
3113	name = migrate->name;
3114	namelen = migrate->namelen;
3115	hash = dlm_lockid_hash(name, namelen);
3116
3117	/* preallocate.. if this fails, abort */
3118	mle = kmem_cache_alloc(cachep: dlm_mle_cache, GFP_NOFS);
3119
3120	if (!mle) {
3121	ret = -ENOMEM;
3122	goto leave;
3123	}
3124
3125	/* check for pre-existing lock */
3126	spin_lock(lock: &dlm->spinlock);
3127	res = __dlm_lookup_lockres(dlm, name, len: namelen, hash);
3128	if (res) {
3129	spin_lock(lock: &res->spinlock);
3130	if (res->state & DLM_LOCK_RES_RECOVERING) {
3131	/* if all is working ok, this can only mean that we got
3132	* a migrate request from a node that we now see as
3133	* dead. what can we do here? drop it to the floor? */
3134	spin_unlock(lock: &res->spinlock);
3135	mlog(ML_ERROR, "Got a migrate request, but the "
3136	"lockres is marked as recovering!");
3137	kmem_cache_free(s: dlm_mle_cache, objp: mle);
3138	ret = -EINVAL; /* need a better solution */
3139	goto unlock;
3140	}
3141	res->state |= DLM_LOCK_RES_MIGRATING;
3142	spin_unlock(lock: &res->spinlock);
3143	}
3144
3145	spin_lock(lock: &dlm->master_lock);
3146	/* ignore status. only nonzero status would BUG. */
3147	ret = dlm_add_migration_mle(dlm, res, mle, oldmle: &oldmle,
3148	name, namelen,
3149	new_master: migrate->new_master,
3150	master: migrate->master);
3151
3152	if (ret < 0)
3153	kmem_cache_free(s: dlm_mle_cache, objp: mle);
3154
3155	spin_unlock(lock: &dlm->master_lock);
3156	unlock:
3157	spin_unlock(lock: &dlm->spinlock);
3158
3159	if (oldmle) {
3160	/* master is known, detach if not already detached */
3161	dlm_mle_detach_hb_events(dlm, mle: oldmle);
3162	dlm_put_mle(mle: oldmle);
3163	}
3164
3165	if (res)
3166	dlm_lockres_put(res);
3167	leave:
3168	dlm_put(dlm);
3169	return ret;
3170	}
3171
3172	/* must be holding dlm->spinlock and dlm->master_lock
3173	* when adding a migration mle, we can clear any other mles
3174	* in the master list because we know with certainty that
3175	* the master is "master". so we remove any old mle from
3176	* the list after setting it's master field, and then add
3177	* the new migration mle. this way we can hold with the rule
3178	* of having only one mle for a given lock name at all times. */
3179	static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
3180	struct dlm_lock_resource *res,
3181	struct dlm_master_list_entry *mle,
3182	struct dlm_master_list_entry **oldmle,
3183	const char *name, unsigned int namelen,
3184	u8 new_master, u8 master)
3185	{
3186	int found;
3187	int ret = 0;
3188
3189	*oldmle = NULL;
3190
3191	assert_spin_locked(&dlm->spinlock);
3192	assert_spin_locked(&dlm->master_lock);
3193
3194	/* caller is responsible for any ref taken here on oldmle */
3195	found = dlm_find_mle(dlm, mle: oldmle, name: (char *)name, namelen);
3196	if (found) {
3197	struct dlm_master_list_entry *tmp = *oldmle;
3198	spin_lock(lock: &tmp->spinlock);
3199	if (tmp->type == DLM_MLE_MIGRATION) {
3200	if (master == dlm->node_num) {
3201	/* ah another process raced me to it */
3202	mlog(0, "tried to migrate %.*s, but some "
3203	"process beat me to it\n",
3204	namelen, name);
3205	spin_unlock(lock: &tmp->spinlock);
3206	return -EEXIST;
3207	} else {
3208	/* bad. 2 NODES are trying to migrate! */
3209	mlog(ML_ERROR, "migration error mle: "
3210	"master=%u new_master=%u // request: "
3211	"master=%u new_master=%u // "
3212	"lockres=%.*s\n",
3213	tmp->master, tmp->new_master,
3214	master, new_master,
3215	namelen, name);
3216	BUG();
3217	}
3218	} else {
3219	/* this is essentially what assert_master does */
3220	tmp->master = master;
3221	atomic_set(v: &tmp->woken, i: 1);
3222	wake_up(&tmp->wq);
3223	/* remove it so that only one mle will be found */
3224	__dlm_unlink_mle(dlm, mle: tmp);
3225	__dlm_mle_detach_hb_events(dlm, mle: tmp);
3226	if (tmp->type == DLM_MLE_MASTER) {
3227	ret = DLM_MIGRATE_RESPONSE_MASTERY_REF;
3228	mlog(0, "%s:%.*s: master=%u, newmaster=%u, "
3229	"telling master to get ref "
3230	"for cleared out mle during "
3231	"migration\n", dlm->name,
3232	namelen, name, master,
3233	new_master);
3234	}
3235	}
3236	spin_unlock(lock: &tmp->spinlock);
3237	}
3238
3239	/* now add a migration mle to the tail of the list */
3240	dlm_init_mle(mle, type: DLM_MLE_MIGRATION, dlm, res, name, namelen);
3241	mle->new_master = new_master;
3242	/* the new master will be sending an assert master for this.
3243	* at that point we will get the refmap reference */
3244	mle->master = master;
3245	/* do this for consistency with other mle types */
3246	set_bit(nr: new_master, addr: mle->maybe_map);
3247	__dlm_insert_mle(dlm, mle);
3248
3249	return ret;
3250	}
3251
3252	/*
3253	* Sets the owner of the lockres, associated to the mle, to UNKNOWN
3254	*/
3255	static struct dlm_lock_resource *dlm_reset_mleres_owner(struct dlm_ctxt *dlm,
3256	struct dlm_master_list_entry *mle)
3257	{
3258	struct dlm_lock_resource *res;
3259
3260	/* Find the lockres associated to the mle and set its owner to UNK */
3261	res = __dlm_lookup_lockres(dlm, name: mle->mname, len: mle->mnamelen,
3262	hash: mle->mnamehash);
3263	if (res) {
3264	spin_unlock(lock: &dlm->master_lock);
3265
3266	/* move lockres onto recovery list */
3267	spin_lock(lock: &res->spinlock);
3268	dlm_set_lockres_owner(dlm, res, DLM_LOCK_RES_OWNER_UNKNOWN);
3269	dlm_move_lockres_to_recovery_list(dlm, res);
3270	spin_unlock(lock: &res->spinlock);
3271	dlm_lockres_put(res);
3272
3273	/* about to get rid of mle, detach from heartbeat */
3274	__dlm_mle_detach_hb_events(dlm, mle);
3275
3276	/* dump the mle */
3277	spin_lock(lock: &dlm->master_lock);
3278	__dlm_put_mle(mle);
3279	spin_unlock(lock: &dlm->master_lock);
3280	}
3281
3282	return res;
3283	}
3284
3285	static void dlm_clean_migration_mle(struct dlm_ctxt *dlm,
3286	struct dlm_master_list_entry *mle)
3287	{
3288	__dlm_mle_detach_hb_events(dlm, mle);
3289
3290	spin_lock(lock: &mle->spinlock);
3291	__dlm_unlink_mle(dlm, mle);
3292	atomic_set(v: &mle->woken, i: 1);
3293	spin_unlock(lock: &mle->spinlock);
3294
3295	wake_up(&mle->wq);
3296	}
3297
3298	static void dlm_clean_block_mle(struct dlm_ctxt *dlm,
3299	struct dlm_master_list_entry *mle, u8 dead_node)
3300	{
3301	int bit;
3302
3303	BUG_ON(mle->type != DLM_MLE_BLOCK);
3304
3305	spin_lock(lock: &mle->spinlock);
3306	bit = find_first_bit(addr: mle->maybe_map, O2NM_MAX_NODES);
3307	if (bit != dead_node) {
3308	mlog(0, "mle found, but dead node %u would not have been "
3309	"master\n", dead_node);
3310	spin_unlock(lock: &mle->spinlock);
3311	} else {
3312	/* Must drop the refcount by one since the assert_master will
3313	* never arrive. This may result in the mle being unlinked and
3314	* freed, but there may still be a process waiting in the
3315	* dlmlock path which is fine. */
3316	mlog(0, "node %u was expected master\n", dead_node);
3317	atomic_set(v: &mle->woken, i: 1);
3318	spin_unlock(lock: &mle->spinlock);
3319	wake_up(&mle->wq);
3320
3321	/* Do not need events any longer, so detach from heartbeat */
3322	__dlm_mle_detach_hb_events(dlm, mle);
3323	__dlm_put_mle(mle);
3324	}
3325	}
3326
3327	void dlm_clean_master_list(struct dlm_ctxt *dlm, u8 dead_node)
3328	{
3329	struct dlm_master_list_entry *mle;
3330	struct dlm_lock_resource *res;
3331	struct hlist_head *bucket;
3332	struct hlist_node *tmp;
3333	unsigned int i;
3334
3335	mlog(0, "dlm=%s, dead node=%u\n", dlm->name, dead_node);
3336	top:
3337	assert_spin_locked(&dlm->spinlock);
3338
3339	/* clean the master list */
3340	spin_lock(lock: &dlm->master_lock);
3341	for (i = 0; i < DLM_HASH_BUCKETS; i++) {
3342	bucket = dlm_master_hash(dlm, i);
3343	hlist_for_each_entry_safe(mle, tmp, bucket, master_hash_node) {
3344	BUG_ON(mle->type != DLM_MLE_BLOCK &&
3345	mle->type != DLM_MLE_MASTER &&
3346	mle->type != DLM_MLE_MIGRATION);
3347
3348	/* MASTER mles are initiated locally. The waiting
3349	* process will notice the node map change shortly.
3350	* Let that happen as normal. */
3351	if (mle->type == DLM_MLE_MASTER)
3352	continue;
3353
3354	/* BLOCK mles are initiated by other nodes. Need to
3355	* clean up if the dead node would have been the
3356	* master. */
3357	if (mle->type == DLM_MLE_BLOCK) {
3358	dlm_clean_block_mle(dlm, mle, dead_node);
3359	continue;
3360	}
3361
3362	/* Everything else is a MIGRATION mle */
3363
3364	/* The rule for MIGRATION mles is that the master
3365	* becomes UNKNOWN if *either* the original or the new
3366	* master dies. All UNKNOWN lockres' are sent to
3367	* whichever node becomes the recovery master. The new
3368	* master is responsible for determining if there is
3369	* still a master for this lockres, or if he needs to
3370	* take over mastery. Either way, this node should
3371	* expect another message to resolve this. */
3372
3373	if (mle->master != dead_node &&
3374	mle->new_master != dead_node)
3375	continue;
3376
3377	if (mle->new_master == dead_node && mle->inuse) {
3378	mlog(ML_NOTICE, "%s: target %u died during "
3379	"migration from %u, the MLE is "
3380	"still keep used, ignore it!\n",
3381	dlm->name, dead_node,
3382	mle->master);
3383	continue;
3384	}
3385
3386	/* If we have reached this point, this mle needs to be
3387	* removed from the list and freed. */
3388	dlm_clean_migration_mle(dlm, mle);
3389
3390	mlog(0, "%s: node %u died during migration from "
3391	"%u to %u!\n", dlm->name, dead_node, mle->master,
3392	mle->new_master);
3393
3394	/* If we find a lockres associated with the mle, we've
3395	* hit this rare case that messes up our lock ordering.
3396	* If so, we need to drop the master lock so that we can
3397	* take the lockres lock, meaning that we will have to
3398	* restart from the head of list. */
3399	res = dlm_reset_mleres_owner(dlm, mle);
3400	if (res)
3401	/* restart */
3402	goto top;
3403
3404	/* This may be the last reference */
3405	__dlm_put_mle(mle);
3406	}
3407	}
3408	spin_unlock(lock: &dlm->master_lock);
3409	}
3410
3411	int dlm_finish_migration(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
3412	u8 old_master)
3413	{
3414	struct dlm_node_iter iter;
3415	int ret = 0;
3416
3417	spin_lock(lock: &dlm->spinlock);
3418	dlm_node_iter_init(map: dlm->domain_map, iter: &iter);
3419	clear_bit(nr: old_master, addr: iter.node_map);
3420	clear_bit(nr: dlm->node_num, addr: iter.node_map);
3421	spin_unlock(lock: &dlm->spinlock);
3422
3423	/* ownership of the lockres is changing. account for the
3424	* mastery reference here since old_master will briefly have
3425	* a reference after the migration completes */
3426	spin_lock(lock: &res->spinlock);
3427	dlm_lockres_set_refmap_bit(dlm, res, bit: old_master);
3428	spin_unlock(lock: &res->spinlock);
3429
3430	mlog(0, "now time to do a migrate request to other nodes\n");
3431	ret = dlm_do_migrate_request(dlm, res, master: old_master,
3432	new_master: dlm->node_num, iter: &iter);
3433	if (ret < 0) {
3434	mlog_errno(ret);
3435	goto leave;
3436	}
3437
3438	mlog(0, "doing assert master of %.*s to all except the original node\n",
3439	res->lockname.len, res->lockname.name);
3440	/* this call now finishes out the nodemap
3441	* even if one or more nodes die */
3442	ret = dlm_do_assert_master(dlm, res, nodemap: iter.node_map,
3443	DLM_ASSERT_MASTER_FINISH_MIGRATION);
3444	if (ret < 0) {
3445	/* no longer need to retry. all living nodes contacted. */
3446	mlog_errno(ret);
3447	ret = 0;
3448	}
3449
3450	bitmap_zero(dst: iter.node_map, O2NM_MAX_NODES);
3451	set_bit(nr: old_master, addr: iter.node_map);
3452	mlog(0, "doing assert master of %.*s back to %u\n",
3453	res->lockname.len, res->lockname.name, old_master);
3454	ret = dlm_do_assert_master(dlm, res, nodemap: iter.node_map,
3455	DLM_ASSERT_MASTER_FINISH_MIGRATION);
3456	if (ret < 0) {
3457	mlog(0, "assert master to original master failed "
3458	"with %d.\n", ret);
3459	/* the only nonzero status here would be because of
3460	* a dead original node. we're done. */
3461	ret = 0;
3462	}
3463
3464	/* all done, set the owner, clear the flag */
3465	spin_lock(lock: &res->spinlock);
3466	dlm_set_lockres_owner(dlm, res, owner: dlm->node_num);
3467	res->state &= ~DLM_LOCK_RES_MIGRATING;
3468	spin_unlock(lock: &res->spinlock);
3469	/* re-dirty it on the new master */
3470	dlm_kick_thread(dlm, res);
3471	wake_up(&res->wq);
3472	leave:
3473	return ret;
3474	}
3475
3476	/*
3477	* LOCKRES AST REFCOUNT
3478	* this is integral to migration
3479	*/
3480
3481	/* for future intent to call an ast, reserve one ahead of time.
3482	* this should be called only after waiting on the lockres
3483	* with dlm_wait_on_lockres, and while still holding the
3484	* spinlock after the call. */
3485	void __dlm_lockres_reserve_ast(struct dlm_lock_resource *res)
3486	{
3487	assert_spin_locked(&res->spinlock);
3488	if (res->state & DLM_LOCK_RES_MIGRATING) {
3489	__dlm_print_one_lock_resource(res);
3490	}
3491	BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
3492
3493	atomic_inc(v: &res->asts_reserved);
3494	}
3495
3496	/*
3497	* used to drop the reserved ast, either because it went unused,
3498	* or because the ast/bast was actually called.
3499	*
3500	* also, if there is a pending migration on this lockres,
3501	* and this was the last pending ast on the lockres,
3502	* atomically set the MIGRATING flag before we drop the lock.
3503	* this is how we ensure that migration can proceed with no
3504	* asts in progress. note that it is ok if the state of the
3505	* queues is such that a lock should be granted in the future
3506	* or that a bast should be fired, because the new master will
3507	* shuffle the lists on this lockres as soon as it is migrated.
3508	*/
3509	void dlm_lockres_release_ast(struct dlm_ctxt *dlm,
3510	struct dlm_lock_resource *res)
3511	{
3512	if (!atomic_dec_and_lock(&res->asts_reserved, &res->spinlock))
3513	return;
3514
3515	if (!res->migration_pending) {
3516	spin_unlock(lock: &res->spinlock);
3517	return;
3518	}
3519
3520	BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
3521	res->migration_pending = 0;
3522	res->state |= DLM_LOCK_RES_MIGRATING;
3523	spin_unlock(lock: &res->spinlock);
3524	wake_up(&res->wq);
3525	wake_up(&dlm->migration_wq);
3526	}
3527
3528	void dlm_force_free_mles(struct dlm_ctxt *dlm)
3529	{
3530	int i;
3531	struct hlist_head *bucket;
3532	struct dlm_master_list_entry *mle;
3533	struct hlist_node *tmp;
3534
3535	/*
3536	* We notified all other nodes that we are exiting the domain and
3537	* marked the dlm state to DLM_CTXT_LEAVING. If any mles are still
3538	* around we force free them and wake any processes that are waiting
3539	* on the mles
3540	*/
3541	spin_lock(lock: &dlm->spinlock);
3542	spin_lock(lock: &dlm->master_lock);
3543
3544	BUG_ON(dlm->dlm_state != DLM_CTXT_LEAVING);
3545	BUG_ON((find_first_bit(dlm->domain_map, O2NM_MAX_NODES) < O2NM_MAX_NODES));
3546
3547	for (i = 0; i < DLM_HASH_BUCKETS; i++) {
3548	bucket = dlm_master_hash(dlm, i);
3549	hlist_for_each_entry_safe(mle, tmp, bucket, master_hash_node) {
3550	if (mle->type != DLM_MLE_BLOCK) {
3551	mlog(ML_ERROR, "bad mle: %p\n", mle);
3552	dlm_print_one_mle(mle);
3553	}
3554	atomic_set(v: &mle->woken, i: 1);
3555	wake_up(&mle->wq);
3556
3557	__dlm_unlink_mle(dlm, mle);
3558	__dlm_mle_detach_hb_events(dlm, mle);
3559	__dlm_put_mle(mle);
3560	}
3561	}
3562	spin_unlock(lock: &dlm->master_lock);
3563	spin_unlock(lock: &dlm->spinlock);
3564	}
3565