summaryrefslogtreecommitdiffstats
path: root/fs/ocfs2/dlm/dlmlock.c
blob: 0ff934874942a423e19478331423408017db0dc3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * dlmlock.c
 *
 * underlying calls for lock creation
 *
 * Copyright (C) 2004 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 *
 */


#include <linux/module.h>
#include <linux/fs.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/highmem.h>
#include <linux/utsname.h>
#include <linux/init.h>
#include <linux/sysctl.h>
#include <linux/random.h>
#include <linux/blkdev.h>
#include <linux/socket.h>
#include <linux/inet.h>
#include <linux/spinlock.h>
#include <linux/delay.h>


#include "cluster/heartbeat.h"
#include "cluster/nodemanager.h"
#include "cluster/tcp.h"

#include "dlmapi.h"
#include "dlmcommon.h"

#include "dlmconvert.h"

#define MLOG_MASK_PREFIX ML_DLM
#include "cluster/masklog.h"

static spinlock_t dlm_cookie_lock = SPIN_LOCK_UNLOCKED;
static u64 dlm_next_cookie = 1;

static enum dlm_status dlm_send_remote_lock_request(struct dlm_ctxt *dlm,
					       struct dlm_lock_resource *res,
					       struct dlm_lock *lock, int flags);
static void dlm_init_lock(struct dlm_lock *newlock, int type,
			  u8 node, u64 cookie);
static void dlm_lock_release(struct kref *kref);
static void dlm_lock_detach_lockres(struct dlm_lock *lock);

/* Tell us whether we can grant a new lock request.
 * locking:
 *   caller needs:  res->spinlock
 *   taken:         none
 *   held on exit:  none
 * returns: 1 if the lock can be granted, 0 otherwise.
 */
static int dlm_can_grant_new_lock(struct dlm_lock_resource *res,
				  struct dlm_lock *lock)
{
	struct list_head *iter;
	struct dlm_lock *tmplock;

	list_for_each(iter, &res->granted) {
		tmplock = list_entry(iter, struct dlm_lock, list);

		if (!dlm_lock_compatible(tmplock->ml.type, lock->ml.type))
			return 0;
	}

	list_for_each(iter, &res->converting) {
		tmplock = list_entry(iter, struct dlm_lock, list);

		if (!dlm_lock_compatible(tmplock->ml.type, lock->ml.type))
			return 0;
	}

	return 1;
}

/* performs lock creation at the lockres master site
 * locking:
 *   caller needs:  none
 *   taken:         takes and drops res->spinlock
 *   held on exit:  none
 * returns: DLM_NORMAL, DLM_NOTQUEUED
 */
static enum dlm_status dlmlock_master(struct dlm_ctxt *dlm,
				      struct dlm_lock_resource *res,
				      struct dlm_lock *lock, int flags)
{
	int call_ast = 0, kick_thread = 0;
	enum dlm_status status = DLM_NORMAL;

	mlog_entry("type=%d\n", lock->ml.type);

	spin_lock(&res->spinlock);
	/* if called from dlm_create_lock_handler, need to
	 * ensure it will not sleep in dlm_wait_on_lockres */
	status = __dlm_lockres_state_to_status(res);
	if (status != DLM_NORMAL &&
	    lock->ml.node != dlm->node_num) {
		/* erf.  state changed after lock was dropped. */
		spin_unlock(&res->spinlock);
		dlm_error(status);
		return status;
	}
	__dlm_wait_on_lockres(res);
	__dlm_lockres_reserve_ast(res);

	if (dlm_can_grant_new_lock(res, lock)) {
		mlog(0, "I can grant this lock right away\n");
		/* got it right away */
		lock->lksb->status = DLM_NORMAL;
		status = DLM_NORMAL;
		dlm_lock_get(lock);
		list_add_tail(&lock->list, &res->granted);

		/* for the recovery lock, we can't allow the ast
		 * to be queued since the dlmthread is already
		 * frozen.  but the recovery lock is always locked
		 * with LKM_NOQUEUE so we do not need the ast in
		 * this special case */
		if (!dlm_is_recovery_lock(res->lockname.name,
					  res->lockname.len)) {
			kick_thread = 1;
			call_ast = 1;
		} else {
			mlog(0, "%s: returning DLM_NORMAL to "
			     "node %u for reco lock\n", dlm->name,
			     lock->ml.node);
		}
	} else {
		/* for NOQUEUE request, unless we get the
		 * lock right away, return DLM_NOTQUEUED */
		if (flags & LKM_NOQUEUE) {
			status = DLM_NOTQUEUED;
			if (dlm_is_recovery_lock(res->lockname.name,
						 res->lockname.len)) {
				mlog(0, "%s: returning NOTQUEUED to "
				     "node %u for reco lock\n", dlm->name,
				     lock->ml.node);
			}
		} else {
			dlm_lock_get(lock);
			list_add_tail(&lock->list, &res->blocked);
			kick_thread = 1;
		}
	}

	spin_unlock(&res->spinlock);
	wake_up(&res->wq);

	/* either queue the ast or release it */
	if (call_ast)
		dlm_queue_ast(dlm, lock);
	else
		dlm_lockres_release_ast(dlm, res);

	dlm_lockres_calc_usage(dlm, res);
	if (kick_thread)
		dlm_kick_thread(dlm, res);

	return status;
}

void dlm_revert_pending_lock(struct dlm_lock_resource *res,
			     struct dlm_lock *lock)
{
	/* remove from local queue if it failed */
	list_del_init(&lock->list);
	lock->lksb->flags &= ~DLM_LKSB_GET_LVB;
}


/*
 * locking:
 *   caller needs:  none
 *   taken:         takes and drops res->spinlock
 *   held on exit:  none
 * returns: DLM_DENIED, DLM_RECOVERING, or net status
 */
static enum dlm_status dlmlock_remote(struct dlm_ctxt *dlm,
				      struct dlm_lock_resource *res,
				      struct dlm_lock *lock, int flags)
{
	enum dlm_status status = DLM_DENIED;
	int lockres_changed = 1;

	mlog_entry("type=%d\n", lock->ml.type);
	mlog(0, "lockres %.*s, flags = 0x%x\n", res->lockname.len,
	     res->lockname.name, flags);

	spin_lock(&res->spinlock);

	/* will exit this call with spinlock held */
	__dlm_wait_on_lockres(res);
	res->state |= DLM_LOCK_RES_IN_PROGRESS;

	/* add lock to local (secondary) queue */
	dlm_lock_get(lock);
	list_add_tail(&lock->list, &res->blocked);
	lock->lock_pending = 1;
	spin_unlock(&res->spinlock);

	/* spec seems to say that you will get DLM_NORMAL when the lock
	 * has been queued, meaning we need to wait for a reply here. */
	status = dlm_send_remote_lock_request(dlm, res, lock, flags);

	spin_lock(&res->spinlock);
	res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
	lock->lock_pending = 0;
	if (status != DLM_NORMAL) {
		if (status != DLM_NOTQUEUED) {
			/*
			 * DO NOT call calc_usage, as this would unhash
			 * the remote lockres before we ever get to use
			 * it.  treat as if we never made any change to
			 * the lockres.
			 */
			lockres_changed = 0;
			dlm_error(status);
		}
		dlm_revert_pending_lock(res, lock);
		dlm_lock_put(lock);
	} else if (dlm_is_recovery_lock(res->lockname.name, 
					res->lockname.len)) {
		/* special case for the $RECOVERY lock.
		 * there will never be an AST delivered to put
		 * this lock on the proper secondary queue
		 * (granted), so do it manually. */
		mlog(0, "%s: $RECOVERY lock for this node (%u) is "
		     "mastered by %u; got lock, manually granting (no ast)\n",
		     dlm->name, dlm->node_num, res->owner);
		list_move_tail(&lock->list, &res->granted);
	}
	spin_unlock(&res->spinlock);

	if (lockres_changed)
		dlm_lockres_calc_usage(dlm, res);

	wake_up(&res->wq);
	return status;
}


/* for remote lock creation.
 * locking:
 *   caller needs:  none, but need res->state & DLM_LOCK_RES_IN_PROGRESS
 *   taken:         none
 *   held on exit:  none
 * returns: DLM_NOLOCKMGR, or net status
 */
static enum dlm_status dlm_send_remote_lock_request(struct dlm_ctxt *dlm,
					       struct dlm_lock_resource *res,
					       struct dlm_lock *lock, int flags)
{
	struct dlm_create_lock create;
	int tmpret, status = 0;
	enum dlm_status ret;

	mlog_entry_void();

	memset(&create, 0, sizeof(create));
	create.node_idx = dlm->node_num;
	create.requested_type = lock->ml.type;
	create.cookie = lock->ml.cookie;
	create.namelen = res->lockname.len;
	create.flags = cpu_to_be32(flags);
	memcpy(create.name, res->lockname.name, create.namelen);

	tmpret = o2net_send_message(DLM_CREATE_LOCK_MSG, dlm->key, &create,
				    sizeof(create), res->owner, &status);
	if (tmpret >= 0) {
		// successfully sent and received
		ret = status;  // this is already a dlm_status
		if (ret == DLM_RECOVERING) {
			mlog(ML_ERROR, "%s:%.*s: BUG.  this is a stale lockres "
			     "no longer owned by %u.  that node is coming back "
			     "up currently.\n", dlm->name, create.namelen,
			     create.name, res->owner);
			dlm_print_one_lock_resource(res);
			BUG();
		}
	} else {
		mlog_errno(tmpret);
		if (dlm_is_host_down(tmpret)) {
			ret = DLM_RECOVERING;
			mlog(0, "node %u died so returning DLM_RECOVERING "
			     "from lock message!\n", res->owner);
		} else {
			ret = dlm_err_to_dlm_status(tmpret);
		}
	}

	return ret;
}

void dlm_lock_get(struct dlm_lock *lock)
{
	kref_get(&lock->lock_refs);
}

void dlm_lock_put(struct dlm_lock *lock)
{
	kref_put(&lock->lock_refs, dlm_lock_release);
}

static void dlm_lock_release(struct kref *kref)
{
	struct dlm_lock *lock;

	lock = container_of(kref, struct dlm_lock, lock_refs);

	BUG_ON(!list_empty(&lock->list));
	BUG_ON(!list_empty(&lock->ast_list));
	BUG_ON(!list_empty(&lock->bast_list));
	BUG_ON(lock->ast_pending);
	BUG_ON(lock->bast_pending);

	dlm_lock_detach_lockres(lock);

	if (lock->lksb_kernel_allocated) {
		mlog(0, "freeing kernel-allocated lksb\n");
		kfree(lock->lksb);
	}
	kfree(lock);
}

/* associate a lock with it's lockres, getting a ref on the lockres */
void dlm_lock_attach_lockres(struct dlm_lock *lock,
			     struct dlm_lock_resource *res)
{
	dlm_lockres_get(res);
	lock->lockres = res;
}

/* drop ref on lockres, if there is still one associated with lock */
static void dlm_lock_detach_lockres(struct dlm_lock *lock)
{
	struct dlm_lock_resource *res;

	res = lock->lockres;
	if (res) {
		lock->lockres = NULL;
		mlog(0, "removing lock's lockres reference\n");
		dlm_lockres_put(res);
	}
}

static void dlm_init_lock(struct dlm_lock *newlock, int type,
			  u8 node, u64 cookie)
{
	INIT_LIST_HEAD(&newlock->list);
	INIT_LIST_HEAD(&newlock->ast_list);
	INIT_LIST_HEAD(&newlock->bast_list);
	spin_lock_init(&newlock->spinlock);
	newlock->ml.type = type;
	newlock->ml.convert_type = LKM_IVMODE;
	newlock->ml.highest_blocked = LKM_IVMODE;
	newlock->ml.node = node;
	newlock->ml.pad1 = 0;
	newlock->ml.list = 0;
	newlock->ml.flags = 0;
	newlock->ast = NULL;
	newlock->bast = NULL;
	newlock->astdata = NULL;
	newlock->ml.cookie = cpu_to_be64(cookie);
	newlock->ast_pending = 0;
	newlock->bast_pending = 0;
	newlock->convert_pending = 0;
	newlock->lock_pending = 0;
	newlock->unlock_pending = 0;
	newlock->cancel_pending = 0;
	newlock->lksb_kernel_allocated = 0;

	kref_init(&newlock->lock_refs);
}

struct dlm_lock * dlm_new_lock(int type, u8 node, u64 cookie,
			       struct dlm_lockstatus *lksb)
{
	struct dlm_lock *lock;
	int kernel_allocated = 0;

	lock = kcalloc(1, sizeof(*lock), GFP_KERNEL);
	if (!lock)
		return NULL;

	if (!lksb) {
		/* zero memory only if kernel-allocated */
		lksb = kcalloc(1, sizeof(*lksb), GFP_KERNEL);
		if (!lksb) {
			kfree(lock);
			return NULL;
		}
		kernel_allocated = 1;
	}

	dlm_init_lock(lock, type, node, cookie);
	if (kernel_allocated)
		lock->lksb_kernel_allocated = 1;
	lock->lksb = lksb;
	lksb->lockid = lock;
	return lock;
}

/* handler for lock creation net message
 * locking:
 *   caller needs:  none
 *   taken:         takes and drops res->spinlock
 *   held on exit:  none
 * returns: DLM_NORMAL, DLM_SYSERR, DLM_IVLOCKID, DLM_NOTQUEUED
 */
int dlm_create_lock_handler(struct o2net_msg *msg, u32 len, void *data)
{
	struct dlm_ctxt *dlm = data;
	struct dlm_create_lock *create = (struct dlm_create_lock *)msg->buf;
	struct dlm_lock_resource *res = NULL;
	struct dlm_lock *newlock = NULL;
	struct dlm_lockstatus *lksb = NULL;
	enum dlm_status status = DLM_NORMAL;
	char *name;
	unsigned int namelen;

	BUG_ON(!dlm);

	mlog_entry_void();

	if (!dlm_grab(dlm))
		return DLM_REJECTED;

	name = create->name;
	namelen = create->namelen;
	status = DLM_RECOVERING;
	if (!dlm_domain_fully_joined(dlm)) {
		mlog(ML_ERROR, "Domain %s not fully joined, but node %u is "
		     "sending a create_lock message for lock %.*s!\n",
		     dlm->name, create->node_idx, namelen, name);
		dlm_error(status);
		goto leave;
	}

	status = DLM_IVBUFLEN;
	if (namelen > DLM_LOCKID_NAME_MAX) {
		dlm_error(status);
		goto leave;
	}

	status = DLM_SYSERR;
	newlock = dlm_new_lock(create->requested_type,
			       create->node_idx,
			       be64_to_cpu(create->cookie), NULL);
	if (!newlock) {
		dlm_error(status);
		goto leave;
	}

	lksb = newlock->lksb;

	if (be32_to_cpu(create->flags) & LKM_GET_LVB) {
		lksb->flags |= DLM_LKSB_GET_LVB;
		mlog(0, "set DLM_LKSB_GET_LVB flag\n");
	}

	status = DLM_IVLOCKID;
	res = dlm_lookup_lockres(dlm, name, namelen);
	if (!res) {
		dlm_error(status);
		goto leave;
	}

	spin_lock(&res->spinlock);
	status = __dlm_lockres_state_to_status(res);
	spin_unlock(&res->spinlock);

	if (status != DLM_NORMAL) {
		mlog(0, "lockres recovering/migrating/in-progress\n");
		goto leave;
	}

	dlm_lock_attach_lockres(newlock, res);

	status = dlmlock_master(dlm, res, newlock, be32_to_cpu(create->flags));
leave:
	if (status != DLM_NORMAL)
		if (newlock)
			dlm_lock_put(newlock);

	if (res)
		dlm_lockres_put(res);

	dlm_put(dlm);

	return status;
}


/* fetch next node-local (u8 nodenum + u56 cookie) into u64 */
static inline void dlm_get_next_cookie(u8 node_num, u64 *cookie)
{
	u64 tmpnode = node_num;

	/* shift single byte of node num into top 8 bits */
	tmpnode <<= 56;

	spin_lock(&dlm_cookie_lock);
	*cookie = (dlm_next_cookie | tmpnode);
	if (++dlm_next_cookie & 0xff00000000000000ull) {
		mlog(0, "This node's cookie will now wrap!\n");
		dlm_next_cookie = 1;
	}
	spin_unlock(&dlm_cookie_lock);
}

enum dlm_status dlmlock(struct dlm_ctxt *dlm, int mode,
			struct dlm_lockstatus *lksb, int flags,
			const char *name, dlm_astlockfunc_t *ast, void *data,
			dlm_bastlockfunc_t *bast)
{
	enum dlm_status status;
	struct dlm_lock_resource *res = NULL;
	struct dlm_lock *lock = NULL;
	int convert = 0, recovery = 0;

	/* yes this function is a mess.
	 * TODO: clean this up.  lots of common code in the
	 *       lock and convert paths, especially in the retry blocks */
	if (!lksb) {
		dlm_error(DLM_BADARGS);
		return DLM_BADARGS;
	}

	status = DLM_BADPARAM;
	if (mode != LKM_EXMODE && mode != LKM_PRMODE && mode != LKM_NLMODE) {
		dlm_error(status);
		goto error;
	}

	if (flags & ~LKM_VALID_FLAGS) {
		dlm_error(status);
		goto error;
	}

	convert = (flags & LKM_CONVERT);
	recovery = (flags & LKM_RECOVERY);

	if (recovery &&
	    (!dlm_is_recovery_lock(name, strlen(name)) || convert) ) {
		dlm_error(status);
		goto error;
	}
	if (convert && (flags & LKM_LOCAL)) {
		mlog(ML_ERROR, "strange LOCAL convert request!\n");
		goto error;
	}

	if (convert) {
		/* CONVERT request */

		/* if converting, must pass in a valid dlm_lock */
		lock = lksb->lockid;
		if (!lock) {
			mlog(ML_ERROR, "NULL lock pointer in convert "
			     "request\n");
			goto error;
		}

		res = lock->lockres;
		if (!res) {
			mlog(ML_ERROR, "NULL lockres pointer in convert "
			     "request\n");
			goto error;
		}
		dlm_lockres_get(res);

		/* XXX: for ocfs2 purposes, the ast/bast/astdata/lksb are
	 	 * static after the original lock call.  convert requests will
		 * ensure that everything is the same, or return DLM_BADARGS.
	 	 * this means that DLM_DENIED_NOASTS will never be returned.
	 	 */
		if (lock->lksb != lksb || lock->ast != ast ||
		    lock->bast != bast || lock->astdata != data) {
			status = DLM_BADARGS;
			mlog(ML_ERROR, "new args:  lksb=%p, ast=%p, bast=%p, "
			     "astdata=%p\n", lksb, ast, bast, data);
			mlog(ML_ERROR, "orig args: lksb=%p, ast=%p, bast=%p, "
			     "astdata=%p\n", lock->lksb, lock->ast,
			     lock->bast, lock->astdata);
			goto error;
		}
retry_convert:
		dlm_wait_for_recovery(dlm);

		if (res->owner == dlm->node_num)
			status = dlmconvert_master(dlm, res, lock, flags, mode);
		else
			status = dlmconvert_remote(dlm, res, lock, flags, mode);
		if (status == DLM_RECOVERING || status == DLM_MIGRATING ||
		    status == DLM_FORWARD) {
			/* for now, see how this works without sleeping
			 * and just retry right away.  I suspect the reco
			 * or migration will complete fast enough that
			 * no waiting will be necessary */
			mlog(0, "retrying convert with migration/recovery/"
			     "in-progress\n");
			msleep(100);
			goto retry_convert;
		}
	} else {
		u64 tmpcookie;

		/* LOCK request */
		status = DLM_BADARGS;
		if (!name) {
			dlm_error(status);
			goto error;
		}

		status = DLM_IVBUFLEN;
		if (strlen(name) > DLM_LOCKID_NAME_MAX || strlen(name) < 1) {
			dlm_error(status);
			goto error;
		}

		dlm_get_next_cookie(dlm->node_num, &tmpcookie);
		lock = dlm_new_lock(mode, dlm->node_num, tmpcookie, lksb);
		if (!lock) {
			dlm_error(status);
			goto error;
		}

		if (!recovery)
			dlm_wait_for_recovery(dlm);

		/* find or create the lock resource */
		res = dlm_get_lock_resource(dlm, name, flags);
		if (!res) {
			status = DLM_IVLOCKID;
			dlm_error(status);
			goto error;
		}

		mlog(0, "type=%d, flags = 0x%x\n", mode, flags);
		mlog(0, "creating lock: lock=%p res=%p\n", lock, res);

		dlm_lock_attach_lockres(lock, res);
		lock->ast = ast;
		lock->bast = bast;
		lock->astdata = data;

retry_lock:
		if (flags & LKM_VALBLK) {
			mlog(0, "LKM_VALBLK passed by caller\n");

			/* LVB requests for non PR, PW or EX locks are
			 * ignored. */
			if (mode < LKM_PRMODE)
				flags &= ~LKM_VALBLK;
			else {
				flags |= LKM_GET_LVB;
				lock->lksb->flags |= DLM_LKSB_GET_LVB;
			}
		}

		if (res->owner == dlm->node_num)
			status = dlmlock_master(dlm, res, lock, flags);
		else
			status = dlmlock_remote(dlm, res, lock, flags);

		if (status == DLM_RECOVERING || status == DLM_MIGRATING ||
		    status == DLM_FORWARD) {
			mlog(0, "retrying lock with migration/"
			     "recovery/in progress\n");
			msleep(100);
			/* no waiting for dlm_reco_thread */
			if (recovery) {
				if (status == DLM_RECOVERING) {
					mlog(0, "%s: got RECOVERING "
					     "for $REOCVERY lock, master "
					     "was %u\n", dlm->name, 
					     res->owner);
					dlm_wait_for_node_death(dlm, res->owner, 
							DLM_NODE_DEATH_WAIT_MAX);
				}
			} else {
				dlm_wait_for_recovery(dlm);
			}
			goto retry_lock;
		}

		if (status != DLM_NORMAL) {
			lock->lksb->flags &= ~DLM_LKSB_GET_LVB;
			if (status != DLM_NOTQUEUED)
				dlm_error(status);
			goto error;
		}
	}

error:
	if (status != DLM_NORMAL) {
		if (lock && !convert)
			dlm_lock_put(lock);
		// this is kind of unnecessary
		lksb->status = status;
	}

	/* put lockres ref from the convert path
	 * or from dlm_get_lock_resource */
	if (res)
		dlm_lockres_put(res);

	return status;
}
EXPORT_SYMBOL_GPL(dlmlock);
OpenPOWER on IntegriCloud