xref: /openbmc/linux/fs/ocfs2/dlm/dlmlock.c (revision 643d1f7f)
1 /* -*- mode: c; c-basic-offset: 8; -*-
2  * vim: noexpandtab sw=8 ts=8 sts=0:
3  *
4  * dlmlock.c
5  *
6  * underlying calls for lock creation
7  *
8  * Copyright (C) 2004 Oracle.  All rights reserved.
9  *
10  * This program is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU General Public
12  * License as published by the Free Software Foundation; either
13  * version 2 of the License, or (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18  * General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public
21  * License along with this program; if not, write to the
22  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
23  * Boston, MA 021110-1307, USA.
24  *
25  */
26 
27 
28 #include <linux/module.h>
29 #include <linux/fs.h>
30 #include <linux/types.h>
31 #include <linux/slab.h>
32 #include <linux/highmem.h>
33 #include <linux/utsname.h>
34 #include <linux/init.h>
35 #include <linux/sysctl.h>
36 #include <linux/random.h>
37 #include <linux/blkdev.h>
38 #include <linux/socket.h>
39 #include <linux/inet.h>
40 #include <linux/spinlock.h>
41 #include <linux/delay.h>
42 
43 
44 #include "cluster/heartbeat.h"
45 #include "cluster/nodemanager.h"
46 #include "cluster/tcp.h"
47 
48 #include "dlmapi.h"
49 #include "dlmcommon.h"
50 
51 #include "dlmconvert.h"
52 
53 #define MLOG_MASK_PREFIX ML_DLM
54 #include "cluster/masklog.h"
55 
56 static DEFINE_SPINLOCK(dlm_cookie_lock);
57 static u64 dlm_next_cookie = 1;
58 
59 static enum dlm_status dlm_send_remote_lock_request(struct dlm_ctxt *dlm,
60 					       struct dlm_lock_resource *res,
61 					       struct dlm_lock *lock, int flags);
62 static void dlm_init_lock(struct dlm_lock *newlock, int type,
63 			  u8 node, u64 cookie);
64 static void dlm_lock_release(struct kref *kref);
65 static void dlm_lock_detach_lockres(struct dlm_lock *lock);
66 
67 /* Tell us whether we can grant a new lock request.
68  * locking:
69  *   caller needs:  res->spinlock
70  *   taken:         none
71  *   held on exit:  none
72  * returns: 1 if the lock can be granted, 0 otherwise.
73  */
74 static int dlm_can_grant_new_lock(struct dlm_lock_resource *res,
75 				  struct dlm_lock *lock)
76 {
77 	struct list_head *iter;
78 	struct dlm_lock *tmplock;
79 
80 	list_for_each(iter, &res->granted) {
81 		tmplock = list_entry(iter, struct dlm_lock, list);
82 
83 		if (!dlm_lock_compatible(tmplock->ml.type, lock->ml.type))
84 			return 0;
85 	}
86 
87 	list_for_each(iter, &res->converting) {
88 		tmplock = list_entry(iter, struct dlm_lock, list);
89 
90 		if (!dlm_lock_compatible(tmplock->ml.type, lock->ml.type))
91 			return 0;
92 	}
93 
94 	return 1;
95 }
96 
97 /* performs lock creation at the lockres master site
98  * locking:
99  *   caller needs:  none
100  *   taken:         takes and drops res->spinlock
101  *   held on exit:  none
102  * returns: DLM_NORMAL, DLM_NOTQUEUED
103  */
104 static enum dlm_status dlmlock_master(struct dlm_ctxt *dlm,
105 				      struct dlm_lock_resource *res,
106 				      struct dlm_lock *lock, int flags)
107 {
108 	int call_ast = 0, kick_thread = 0;
109 	enum dlm_status status = DLM_NORMAL;
110 
111 	mlog_entry("type=%d\n", lock->ml.type);
112 
113 	spin_lock(&res->spinlock);
114 	/* if called from dlm_create_lock_handler, need to
115 	 * ensure it will not sleep in dlm_wait_on_lockres */
116 	status = __dlm_lockres_state_to_status(res);
117 	if (status != DLM_NORMAL &&
118 	    lock->ml.node != dlm->node_num) {
119 		/* erf.  state changed after lock was dropped. */
120 		spin_unlock(&res->spinlock);
121 		dlm_error(status);
122 		return status;
123 	}
124 	__dlm_wait_on_lockres(res);
125 	__dlm_lockres_reserve_ast(res);
126 
127 	if (dlm_can_grant_new_lock(res, lock)) {
128 		mlog(0, "I can grant this lock right away\n");
129 		/* got it right away */
130 		lock->lksb->status = DLM_NORMAL;
131 		status = DLM_NORMAL;
132 		dlm_lock_get(lock);
133 		list_add_tail(&lock->list, &res->granted);
134 
135 		/* for the recovery lock, we can't allow the ast
136 		 * to be queued since the dlmthread is already
137 		 * frozen.  but the recovery lock is always locked
138 		 * with LKM_NOQUEUE so we do not need the ast in
139 		 * this special case */
140 		if (!dlm_is_recovery_lock(res->lockname.name,
141 					  res->lockname.len)) {
142 			kick_thread = 1;
143 			call_ast = 1;
144 		} else {
145 			mlog(0, "%s: returning DLM_NORMAL to "
146 			     "node %u for reco lock\n", dlm->name,
147 			     lock->ml.node);
148 		}
149 	} else {
150 		/* for NOQUEUE request, unless we get the
151 		 * lock right away, return DLM_NOTQUEUED */
152 		if (flags & LKM_NOQUEUE) {
153 			status = DLM_NOTQUEUED;
154 			if (dlm_is_recovery_lock(res->lockname.name,
155 						 res->lockname.len)) {
156 				mlog(0, "%s: returning NOTQUEUED to "
157 				     "node %u for reco lock\n", dlm->name,
158 				     lock->ml.node);
159 			}
160 		} else {
161 			dlm_lock_get(lock);
162 			list_add_tail(&lock->list, &res->blocked);
163 			kick_thread = 1;
164 		}
165 	}
166 	/* reduce the inflight count, this may result in the lockres
167 	 * being purged below during calc_usage */
168 	if (lock->ml.node == dlm->node_num)
169 		dlm_lockres_drop_inflight_ref(dlm, res);
170 
171 	spin_unlock(&res->spinlock);
172 	wake_up(&res->wq);
173 
174 	/* either queue the ast or release it */
175 	if (call_ast)
176 		dlm_queue_ast(dlm, lock);
177 	else
178 		dlm_lockres_release_ast(dlm, res);
179 
180 	dlm_lockres_calc_usage(dlm, res);
181 	if (kick_thread)
182 		dlm_kick_thread(dlm, res);
183 
184 	return status;
185 }
186 
187 void dlm_revert_pending_lock(struct dlm_lock_resource *res,
188 			     struct dlm_lock *lock)
189 {
190 	/* remove from local queue if it failed */
191 	list_del_init(&lock->list);
192 	lock->lksb->flags &= ~DLM_LKSB_GET_LVB;
193 }
194 
195 
196 /*
197  * locking:
198  *   caller needs:  none
199  *   taken:         takes and drops res->spinlock
200  *   held on exit:  none
201  * returns: DLM_DENIED, DLM_RECOVERING, or net status
202  */
203 static enum dlm_status dlmlock_remote(struct dlm_ctxt *dlm,
204 				      struct dlm_lock_resource *res,
205 				      struct dlm_lock *lock, int flags)
206 {
207 	enum dlm_status status = DLM_DENIED;
208 	int lockres_changed = 1;
209 
210 	mlog_entry("type=%d\n", lock->ml.type);
211 	mlog(0, "lockres %.*s, flags = 0x%x\n", res->lockname.len,
212 	     res->lockname.name, flags);
213 
214 	spin_lock(&res->spinlock);
215 
216 	/* will exit this call with spinlock held */
217 	__dlm_wait_on_lockres(res);
218 	res->state |= DLM_LOCK_RES_IN_PROGRESS;
219 
220 	/* add lock to local (secondary) queue */
221 	dlm_lock_get(lock);
222 	list_add_tail(&lock->list, &res->blocked);
223 	lock->lock_pending = 1;
224 	spin_unlock(&res->spinlock);
225 
226 	/* spec seems to say that you will get DLM_NORMAL when the lock
227 	 * has been queued, meaning we need to wait for a reply here. */
228 	status = dlm_send_remote_lock_request(dlm, res, lock, flags);
229 
230 	spin_lock(&res->spinlock);
231 	res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
232 	lock->lock_pending = 0;
233 	if (status != DLM_NORMAL) {
234 		if (status == DLM_RECOVERING &&
235 		    dlm_is_recovery_lock(res->lockname.name,
236 					 res->lockname.len)) {
237 			/* recovery lock was mastered by dead node.
238 			 * we need to have calc_usage shoot down this
239 			 * lockres and completely remaster it. */
240 			mlog(0, "%s: recovery lock was owned by "
241 			     "dead node %u, remaster it now.\n",
242 			     dlm->name, res->owner);
243 		} else if (status != DLM_NOTQUEUED) {
244 			/*
245 			 * DO NOT call calc_usage, as this would unhash
246 			 * the remote lockres before we ever get to use
247 			 * it.  treat as if we never made any change to
248 			 * the lockres.
249 			 */
250 			lockres_changed = 0;
251 			dlm_error(status);
252 		}
253 		dlm_revert_pending_lock(res, lock);
254 		dlm_lock_put(lock);
255 	} else if (dlm_is_recovery_lock(res->lockname.name,
256 					res->lockname.len)) {
257 		/* special case for the $RECOVERY lock.
258 		 * there will never be an AST delivered to put
259 		 * this lock on the proper secondary queue
260 		 * (granted), so do it manually. */
261 		mlog(0, "%s: $RECOVERY lock for this node (%u) is "
262 		     "mastered by %u; got lock, manually granting (no ast)\n",
263 		     dlm->name, dlm->node_num, res->owner);
264 		list_move_tail(&lock->list, &res->granted);
265 	}
266 	spin_unlock(&res->spinlock);
267 
268 	if (lockres_changed)
269 		dlm_lockres_calc_usage(dlm, res);
270 
271 	wake_up(&res->wq);
272 	return status;
273 }
274 
275 
276 /* for remote lock creation.
277  * locking:
278  *   caller needs:  none, but need res->state & DLM_LOCK_RES_IN_PROGRESS
279  *   taken:         none
280  *   held on exit:  none
281  * returns: DLM_NOLOCKMGR, or net status
282  */
283 static enum dlm_status dlm_send_remote_lock_request(struct dlm_ctxt *dlm,
284 					       struct dlm_lock_resource *res,
285 					       struct dlm_lock *lock, int flags)
286 {
287 	struct dlm_create_lock create;
288 	int tmpret, status = 0;
289 	enum dlm_status ret;
290 
291 	mlog_entry_void();
292 
293 	memset(&create, 0, sizeof(create));
294 	create.node_idx = dlm->node_num;
295 	create.requested_type = lock->ml.type;
296 	create.cookie = lock->ml.cookie;
297 	create.namelen = res->lockname.len;
298 	create.flags = cpu_to_be32(flags);
299 	memcpy(create.name, res->lockname.name, create.namelen);
300 
301 	tmpret = o2net_send_message(DLM_CREATE_LOCK_MSG, dlm->key, &create,
302 				    sizeof(create), res->owner, &status);
303 	if (tmpret >= 0) {
304 		// successfully sent and received
305 		ret = status;  // this is already a dlm_status
306 		if (ret == DLM_REJECTED) {
307 			mlog(ML_ERROR, "%s:%.*s: BUG.  this is a stale lockres "
308 			     "no longer owned by %u.  that node is coming back "
309 			     "up currently.\n", dlm->name, create.namelen,
310 			     create.name, res->owner);
311 			dlm_print_one_lock_resource(res);
312 			BUG();
313 		}
314 	} else {
315 		mlog_errno(tmpret);
316 		if (dlm_is_host_down(tmpret)) {
317 			ret = DLM_RECOVERING;
318 			mlog(0, "node %u died so returning DLM_RECOVERING "
319 			     "from lock message!\n", res->owner);
320 		} else {
321 			ret = dlm_err_to_dlm_status(tmpret);
322 		}
323 	}
324 
325 	return ret;
326 }
327 
328 void dlm_lock_get(struct dlm_lock *lock)
329 {
330 	kref_get(&lock->lock_refs);
331 }
332 
333 void dlm_lock_put(struct dlm_lock *lock)
334 {
335 	kref_put(&lock->lock_refs, dlm_lock_release);
336 }
337 
338 static void dlm_lock_release(struct kref *kref)
339 {
340 	struct dlm_lock *lock;
341 
342 	lock = container_of(kref, struct dlm_lock, lock_refs);
343 
344 	BUG_ON(!list_empty(&lock->list));
345 	BUG_ON(!list_empty(&lock->ast_list));
346 	BUG_ON(!list_empty(&lock->bast_list));
347 	BUG_ON(lock->ast_pending);
348 	BUG_ON(lock->bast_pending);
349 
350 	dlm_lock_detach_lockres(lock);
351 
352 	if (lock->lksb_kernel_allocated) {
353 		mlog(0, "freeing kernel-allocated lksb\n");
354 		kfree(lock->lksb);
355 	}
356 	kfree(lock);
357 }
358 
359 /* associate a lock with it's lockres, getting a ref on the lockres */
360 void dlm_lock_attach_lockres(struct dlm_lock *lock,
361 			     struct dlm_lock_resource *res)
362 {
363 	dlm_lockres_get(res);
364 	lock->lockres = res;
365 }
366 
367 /* drop ref on lockres, if there is still one associated with lock */
368 static void dlm_lock_detach_lockres(struct dlm_lock *lock)
369 {
370 	struct dlm_lock_resource *res;
371 
372 	res = lock->lockres;
373 	if (res) {
374 		lock->lockres = NULL;
375 		mlog(0, "removing lock's lockres reference\n");
376 		dlm_lockres_put(res);
377 	}
378 }
379 
380 static void dlm_init_lock(struct dlm_lock *newlock, int type,
381 			  u8 node, u64 cookie)
382 {
383 	INIT_LIST_HEAD(&newlock->list);
384 	INIT_LIST_HEAD(&newlock->ast_list);
385 	INIT_LIST_HEAD(&newlock->bast_list);
386 	spin_lock_init(&newlock->spinlock);
387 	newlock->ml.type = type;
388 	newlock->ml.convert_type = LKM_IVMODE;
389 	newlock->ml.highest_blocked = LKM_IVMODE;
390 	newlock->ml.node = node;
391 	newlock->ml.pad1 = 0;
392 	newlock->ml.list = 0;
393 	newlock->ml.flags = 0;
394 	newlock->ast = NULL;
395 	newlock->bast = NULL;
396 	newlock->astdata = NULL;
397 	newlock->ml.cookie = cpu_to_be64(cookie);
398 	newlock->ast_pending = 0;
399 	newlock->bast_pending = 0;
400 	newlock->convert_pending = 0;
401 	newlock->lock_pending = 0;
402 	newlock->unlock_pending = 0;
403 	newlock->cancel_pending = 0;
404 	newlock->lksb_kernel_allocated = 0;
405 
406 	kref_init(&newlock->lock_refs);
407 }
408 
409 struct dlm_lock * dlm_new_lock(int type, u8 node, u64 cookie,
410 			       struct dlm_lockstatus *lksb)
411 {
412 	struct dlm_lock *lock;
413 	int kernel_allocated = 0;
414 
415 	lock = kzalloc(sizeof(*lock), GFP_NOFS);
416 	if (!lock)
417 		return NULL;
418 
419 	if (!lksb) {
420 		/* zero memory only if kernel-allocated */
421 		lksb = kzalloc(sizeof(*lksb), GFP_NOFS);
422 		if (!lksb) {
423 			kfree(lock);
424 			return NULL;
425 		}
426 		kernel_allocated = 1;
427 	}
428 
429 	dlm_init_lock(lock, type, node, cookie);
430 	if (kernel_allocated)
431 		lock->lksb_kernel_allocated = 1;
432 	lock->lksb = lksb;
433 	lksb->lockid = lock;
434 	return lock;
435 }
436 
437 /* handler for lock creation net message
438  * locking:
439  *   caller needs:  none
440  *   taken:         takes and drops res->spinlock
441  *   held on exit:  none
442  * returns: DLM_NORMAL, DLM_SYSERR, DLM_IVLOCKID, DLM_NOTQUEUED
443  */
444 int dlm_create_lock_handler(struct o2net_msg *msg, u32 len, void *data,
445 			    void **ret_data)
446 {
447 	struct dlm_ctxt *dlm = data;
448 	struct dlm_create_lock *create = (struct dlm_create_lock *)msg->buf;
449 	struct dlm_lock_resource *res = NULL;
450 	struct dlm_lock *newlock = NULL;
451 	struct dlm_lockstatus *lksb = NULL;
452 	enum dlm_status status = DLM_NORMAL;
453 	char *name;
454 	unsigned int namelen;
455 
456 	BUG_ON(!dlm);
457 
458 	mlog_entry_void();
459 
460 	if (!dlm_grab(dlm))
461 		return DLM_REJECTED;
462 
463 	name = create->name;
464 	namelen = create->namelen;
465 	status = DLM_REJECTED;
466 	if (!dlm_domain_fully_joined(dlm)) {
467 		mlog(ML_ERROR, "Domain %s not fully joined, but node %u is "
468 		     "sending a create_lock message for lock %.*s!\n",
469 		     dlm->name, create->node_idx, namelen, name);
470 		dlm_error(status);
471 		goto leave;
472 	}
473 
474 	status = DLM_IVBUFLEN;
475 	if (namelen > DLM_LOCKID_NAME_MAX) {
476 		dlm_error(status);
477 		goto leave;
478 	}
479 
480 	status = DLM_SYSERR;
481 	newlock = dlm_new_lock(create->requested_type,
482 			       create->node_idx,
483 			       be64_to_cpu(create->cookie), NULL);
484 	if (!newlock) {
485 		dlm_error(status);
486 		goto leave;
487 	}
488 
489 	lksb = newlock->lksb;
490 
491 	if (be32_to_cpu(create->flags) & LKM_GET_LVB) {
492 		lksb->flags |= DLM_LKSB_GET_LVB;
493 		mlog(0, "set DLM_LKSB_GET_LVB flag\n");
494 	}
495 
496 	status = DLM_IVLOCKID;
497 	res = dlm_lookup_lockres(dlm, name, namelen);
498 	if (!res) {
499 		dlm_error(status);
500 		goto leave;
501 	}
502 
503 	spin_lock(&res->spinlock);
504 	status = __dlm_lockres_state_to_status(res);
505 	spin_unlock(&res->spinlock);
506 
507 	if (status != DLM_NORMAL) {
508 		mlog(0, "lockres recovering/migrating/in-progress\n");
509 		goto leave;
510 	}
511 
512 	dlm_lock_attach_lockres(newlock, res);
513 
514 	status = dlmlock_master(dlm, res, newlock, be32_to_cpu(create->flags));
515 leave:
516 	if (status != DLM_NORMAL)
517 		if (newlock)
518 			dlm_lock_put(newlock);
519 
520 	if (res)
521 		dlm_lockres_put(res);
522 
523 	dlm_put(dlm);
524 
525 	return status;
526 }
527 
528 
529 /* fetch next node-local (u8 nodenum + u56 cookie) into u64 */
530 static inline void dlm_get_next_cookie(u8 node_num, u64 *cookie)
531 {
532 	u64 tmpnode = node_num;
533 
534 	/* shift single byte of node num into top 8 bits */
535 	tmpnode <<= 56;
536 
537 	spin_lock(&dlm_cookie_lock);
538 	*cookie = (dlm_next_cookie | tmpnode);
539 	if (++dlm_next_cookie & 0xff00000000000000ull) {
540 		mlog(0, "This node's cookie will now wrap!\n");
541 		dlm_next_cookie = 1;
542 	}
543 	spin_unlock(&dlm_cookie_lock);
544 }
545 
546 enum dlm_status dlmlock(struct dlm_ctxt *dlm, int mode,
547 			struct dlm_lockstatus *lksb, int flags,
548 			const char *name, int namelen, dlm_astlockfunc_t *ast,
549 			void *data, dlm_bastlockfunc_t *bast)
550 {
551 	enum dlm_status status;
552 	struct dlm_lock_resource *res = NULL;
553 	struct dlm_lock *lock = NULL;
554 	int convert = 0, recovery = 0;
555 
556 	/* yes this function is a mess.
557 	 * TODO: clean this up.  lots of common code in the
558 	 *       lock and convert paths, especially in the retry blocks */
559 	if (!lksb) {
560 		dlm_error(DLM_BADARGS);
561 		return DLM_BADARGS;
562 	}
563 
564 	status = DLM_BADPARAM;
565 	if (mode != LKM_EXMODE && mode != LKM_PRMODE && mode != LKM_NLMODE) {
566 		dlm_error(status);
567 		goto error;
568 	}
569 
570 	if (flags & ~LKM_VALID_FLAGS) {
571 		dlm_error(status);
572 		goto error;
573 	}
574 
575 	convert = (flags & LKM_CONVERT);
576 	recovery = (flags & LKM_RECOVERY);
577 
578 	if (recovery &&
579 	    (!dlm_is_recovery_lock(name, namelen) || convert) ) {
580 		dlm_error(status);
581 		goto error;
582 	}
583 	if (convert && (flags & LKM_LOCAL)) {
584 		mlog(ML_ERROR, "strange LOCAL convert request!\n");
585 		goto error;
586 	}
587 
588 	if (convert) {
589 		/* CONVERT request */
590 
591 		/* if converting, must pass in a valid dlm_lock */
592 		lock = lksb->lockid;
593 		if (!lock) {
594 			mlog(ML_ERROR, "NULL lock pointer in convert "
595 			     "request\n");
596 			goto error;
597 		}
598 
599 		res = lock->lockres;
600 		if (!res) {
601 			mlog(ML_ERROR, "NULL lockres pointer in convert "
602 			     "request\n");
603 			goto error;
604 		}
605 		dlm_lockres_get(res);
606 
607 		/* XXX: for ocfs2 purposes, the ast/bast/astdata/lksb are
608 	 	 * static after the original lock call.  convert requests will
609 		 * ensure that everything is the same, or return DLM_BADARGS.
610 	 	 * this means that DLM_DENIED_NOASTS will never be returned.
611 	 	 */
612 		if (lock->lksb != lksb || lock->ast != ast ||
613 		    lock->bast != bast || lock->astdata != data) {
614 			status = DLM_BADARGS;
615 			mlog(ML_ERROR, "new args:  lksb=%p, ast=%p, bast=%p, "
616 			     "astdata=%p\n", lksb, ast, bast, data);
617 			mlog(ML_ERROR, "orig args: lksb=%p, ast=%p, bast=%p, "
618 			     "astdata=%p\n", lock->lksb, lock->ast,
619 			     lock->bast, lock->astdata);
620 			goto error;
621 		}
622 retry_convert:
623 		dlm_wait_for_recovery(dlm);
624 
625 		if (res->owner == dlm->node_num)
626 			status = dlmconvert_master(dlm, res, lock, flags, mode);
627 		else
628 			status = dlmconvert_remote(dlm, res, lock, flags, mode);
629 		if (status == DLM_RECOVERING || status == DLM_MIGRATING ||
630 		    status == DLM_FORWARD) {
631 			/* for now, see how this works without sleeping
632 			 * and just retry right away.  I suspect the reco
633 			 * or migration will complete fast enough that
634 			 * no waiting will be necessary */
635 			mlog(0, "retrying convert with migration/recovery/"
636 			     "in-progress\n");
637 			msleep(100);
638 			goto retry_convert;
639 		}
640 	} else {
641 		u64 tmpcookie;
642 
643 		/* LOCK request */
644 		status = DLM_BADARGS;
645 		if (!name) {
646 			dlm_error(status);
647 			goto error;
648 		}
649 
650 		status = DLM_IVBUFLEN;
651 		if (namelen > DLM_LOCKID_NAME_MAX || namelen < 1) {
652 			dlm_error(status);
653 			goto error;
654 		}
655 
656 		dlm_get_next_cookie(dlm->node_num, &tmpcookie);
657 		lock = dlm_new_lock(mode, dlm->node_num, tmpcookie, lksb);
658 		if (!lock) {
659 			dlm_error(status);
660 			goto error;
661 		}
662 
663 		if (!recovery)
664 			dlm_wait_for_recovery(dlm);
665 
666 		/* find or create the lock resource */
667 		res = dlm_get_lock_resource(dlm, name, namelen, flags);
668 		if (!res) {
669 			status = DLM_IVLOCKID;
670 			dlm_error(status);
671 			goto error;
672 		}
673 
674 		mlog(0, "type=%d, flags = 0x%x\n", mode, flags);
675 		mlog(0, "creating lock: lock=%p res=%p\n", lock, res);
676 
677 		dlm_lock_attach_lockres(lock, res);
678 		lock->ast = ast;
679 		lock->bast = bast;
680 		lock->astdata = data;
681 
682 retry_lock:
683 		if (flags & LKM_VALBLK) {
684 			mlog(0, "LKM_VALBLK passed by caller\n");
685 
686 			/* LVB requests for non PR, PW or EX locks are
687 			 * ignored. */
688 			if (mode < LKM_PRMODE)
689 				flags &= ~LKM_VALBLK;
690 			else {
691 				flags |= LKM_GET_LVB;
692 				lock->lksb->flags |= DLM_LKSB_GET_LVB;
693 			}
694 		}
695 
696 		if (res->owner == dlm->node_num)
697 			status = dlmlock_master(dlm, res, lock, flags);
698 		else
699 			status = dlmlock_remote(dlm, res, lock, flags);
700 
701 		if (status == DLM_RECOVERING || status == DLM_MIGRATING ||
702 		    status == DLM_FORWARD) {
703 			mlog(0, "retrying lock with migration/"
704 			     "recovery/in progress\n");
705 			msleep(100);
706 			/* no waiting for dlm_reco_thread */
707 			if (recovery) {
708 				if (status != DLM_RECOVERING)
709 					goto retry_lock;
710 
711 				mlog(0, "%s: got RECOVERING "
712 				     "for $RECOVERY lock, master "
713 				     "was %u\n", dlm->name,
714 				     res->owner);
715 				/* wait to see the node go down, then
716 				 * drop down and allow the lockres to
717 				 * get cleaned up.  need to remaster. */
718 				dlm_wait_for_node_death(dlm, res->owner,
719 						DLM_NODE_DEATH_WAIT_MAX);
720 			} else {
721 				dlm_wait_for_recovery(dlm);
722 				goto retry_lock;
723 			}
724 		}
725 
726 		if (status != DLM_NORMAL) {
727 			lock->lksb->flags &= ~DLM_LKSB_GET_LVB;
728 			if (status != DLM_NOTQUEUED)
729 				dlm_error(status);
730 			goto error;
731 		}
732 	}
733 
734 error:
735 	if (status != DLM_NORMAL) {
736 		if (lock && !convert)
737 			dlm_lock_put(lock);
738 		// this is kind of unnecessary
739 		lksb->status = status;
740 	}
741 
742 	/* put lockres ref from the convert path
743 	 * or from dlm_get_lock_resource */
744 	if (res)
745 		dlm_lockres_put(res);
746 
747 	return status;
748 }
749 EXPORT_SYMBOL_GPL(dlmlock);
750