xref: /linux/fs/ocfs2/dlm/dlmlock.c (revision 14b42963f64b98ab61fa9723c03d71aa5ef4f862)
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 
167 	spin_unlock(&res->spinlock);
168 	wake_up(&res->wq);
169 
170 	/* either queue the ast or release it */
171 	if (call_ast)
172 		dlm_queue_ast(dlm, lock);
173 	else
174 		dlm_lockres_release_ast(dlm, res);
175 
176 	dlm_lockres_calc_usage(dlm, res);
177 	if (kick_thread)
178 		dlm_kick_thread(dlm, res);
179 
180 	return status;
181 }
182 
183 void dlm_revert_pending_lock(struct dlm_lock_resource *res,
184 			     struct dlm_lock *lock)
185 {
186 	/* remove from local queue if it failed */
187 	list_del_init(&lock->list);
188 	lock->lksb->flags &= ~DLM_LKSB_GET_LVB;
189 }
190 
191 
192 /*
193  * locking:
194  *   caller needs:  none
195  *   taken:         takes and drops res->spinlock
196  *   held on exit:  none
197  * returns: DLM_DENIED, DLM_RECOVERING, or net status
198  */
199 static enum dlm_status dlmlock_remote(struct dlm_ctxt *dlm,
200 				      struct dlm_lock_resource *res,
201 				      struct dlm_lock *lock, int flags)
202 {
203 	enum dlm_status status = DLM_DENIED;
204 	int lockres_changed = 1;
205 
206 	mlog_entry("type=%d\n", lock->ml.type);
207 	mlog(0, "lockres %.*s, flags = 0x%x\n", res->lockname.len,
208 	     res->lockname.name, flags);
209 
210 	spin_lock(&res->spinlock);
211 
212 	/* will exit this call with spinlock held */
213 	__dlm_wait_on_lockres(res);
214 	res->state |= DLM_LOCK_RES_IN_PROGRESS;
215 
216 	/* add lock to local (secondary) queue */
217 	dlm_lock_get(lock);
218 	list_add_tail(&lock->list, &res->blocked);
219 	lock->lock_pending = 1;
220 	spin_unlock(&res->spinlock);
221 
222 	/* spec seems to say that you will get DLM_NORMAL when the lock
223 	 * has been queued, meaning we need to wait for a reply here. */
224 	status = dlm_send_remote_lock_request(dlm, res, lock, flags);
225 
226 	spin_lock(&res->spinlock);
227 	res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
228 	lock->lock_pending = 0;
229 	if (status != DLM_NORMAL) {
230 		if (status == DLM_RECOVERING &&
231 		    dlm_is_recovery_lock(res->lockname.name,
232 					 res->lockname.len)) {
233 			/* recovery lock was mastered by dead node.
234 			 * we need to have calc_usage shoot down this
235 			 * lockres and completely remaster it. */
236 			mlog(0, "%s: recovery lock was owned by "
237 			     "dead node %u, remaster it now.\n",
238 			     dlm->name, res->owner);
239 		} else if (status != DLM_NOTQUEUED) {
240 			/*
241 			 * DO NOT call calc_usage, as this would unhash
242 			 * the remote lockres before we ever get to use
243 			 * it.  treat as if we never made any change to
244 			 * the lockres.
245 			 */
246 			lockres_changed = 0;
247 			dlm_error(status);
248 		}
249 		dlm_revert_pending_lock(res, lock);
250 		dlm_lock_put(lock);
251 	} else if (dlm_is_recovery_lock(res->lockname.name,
252 					res->lockname.len)) {
253 		/* special case for the $RECOVERY lock.
254 		 * there will never be an AST delivered to put
255 		 * this lock on the proper secondary queue
256 		 * (granted), so do it manually. */
257 		mlog(0, "%s: $RECOVERY lock for this node (%u) is "
258 		     "mastered by %u; got lock, manually granting (no ast)\n",
259 		     dlm->name, dlm->node_num, res->owner);
260 		list_move_tail(&lock->list, &res->granted);
261 	}
262 	spin_unlock(&res->spinlock);
263 
264 	if (lockres_changed)
265 		dlm_lockres_calc_usage(dlm, res);
266 
267 	wake_up(&res->wq);
268 	return status;
269 }
270 
271 
272 /* for remote lock creation.
273  * locking:
274  *   caller needs:  none, but need res->state & DLM_LOCK_RES_IN_PROGRESS
275  *   taken:         none
276  *   held on exit:  none
277  * returns: DLM_NOLOCKMGR, or net status
278  */
279 static enum dlm_status dlm_send_remote_lock_request(struct dlm_ctxt *dlm,
280 					       struct dlm_lock_resource *res,
281 					       struct dlm_lock *lock, int flags)
282 {
283 	struct dlm_create_lock create;
284 	int tmpret, status = 0;
285 	enum dlm_status ret;
286 
287 	mlog_entry_void();
288 
289 	memset(&create, 0, sizeof(create));
290 	create.node_idx = dlm->node_num;
291 	create.requested_type = lock->ml.type;
292 	create.cookie = lock->ml.cookie;
293 	create.namelen = res->lockname.len;
294 	create.flags = cpu_to_be32(flags);
295 	memcpy(create.name, res->lockname.name, create.namelen);
296 
297 	tmpret = o2net_send_message(DLM_CREATE_LOCK_MSG, dlm->key, &create,
298 				    sizeof(create), res->owner, &status);
299 	if (tmpret >= 0) {
300 		// successfully sent and received
301 		ret = status;  // this is already a dlm_status
302 		if (ret == DLM_REJECTED) {
303 			mlog(ML_ERROR, "%s:%.*s: BUG.  this is a stale lockres "
304 			     "no longer owned by %u.  that node is coming back "
305 			     "up currently.\n", dlm->name, create.namelen,
306 			     create.name, res->owner);
307 			dlm_print_one_lock_resource(res);
308 			BUG();
309 		}
310 	} else {
311 		mlog_errno(tmpret);
312 		if (dlm_is_host_down(tmpret)) {
313 			ret = DLM_RECOVERING;
314 			mlog(0, "node %u died so returning DLM_RECOVERING "
315 			     "from lock message!\n", res->owner);
316 		} else {
317 			ret = dlm_err_to_dlm_status(tmpret);
318 		}
319 	}
320 
321 	return ret;
322 }
323 
324 void dlm_lock_get(struct dlm_lock *lock)
325 {
326 	kref_get(&lock->lock_refs);
327 }
328 
329 void dlm_lock_put(struct dlm_lock *lock)
330 {
331 	kref_put(&lock->lock_refs, dlm_lock_release);
332 }
333 
334 static void dlm_lock_release(struct kref *kref)
335 {
336 	struct dlm_lock *lock;
337 
338 	lock = container_of(kref, struct dlm_lock, lock_refs);
339 
340 	BUG_ON(!list_empty(&lock->list));
341 	BUG_ON(!list_empty(&lock->ast_list));
342 	BUG_ON(!list_empty(&lock->bast_list));
343 	BUG_ON(lock->ast_pending);
344 	BUG_ON(lock->bast_pending);
345 
346 	dlm_lock_detach_lockres(lock);
347 
348 	if (lock->lksb_kernel_allocated) {
349 		mlog(0, "freeing kernel-allocated lksb\n");
350 		kfree(lock->lksb);
351 	}
352 	kfree(lock);
353 }
354 
355 /* associate a lock with it's lockres, getting a ref on the lockres */
356 void dlm_lock_attach_lockres(struct dlm_lock *lock,
357 			     struct dlm_lock_resource *res)
358 {
359 	dlm_lockres_get(res);
360 	lock->lockres = res;
361 }
362 
363 /* drop ref on lockres, if there is still one associated with lock */
364 static void dlm_lock_detach_lockres(struct dlm_lock *lock)
365 {
366 	struct dlm_lock_resource *res;
367 
368 	res = lock->lockres;
369 	if (res) {
370 		lock->lockres = NULL;
371 		mlog(0, "removing lock's lockres reference\n");
372 		dlm_lockres_put(res);
373 	}
374 }
375 
376 static void dlm_init_lock(struct dlm_lock *newlock, int type,
377 			  u8 node, u64 cookie)
378 {
379 	INIT_LIST_HEAD(&newlock->list);
380 	INIT_LIST_HEAD(&newlock->ast_list);
381 	INIT_LIST_HEAD(&newlock->bast_list);
382 	spin_lock_init(&newlock->spinlock);
383 	newlock->ml.type = type;
384 	newlock->ml.convert_type = LKM_IVMODE;
385 	newlock->ml.highest_blocked = LKM_IVMODE;
386 	newlock->ml.node = node;
387 	newlock->ml.pad1 = 0;
388 	newlock->ml.list = 0;
389 	newlock->ml.flags = 0;
390 	newlock->ast = NULL;
391 	newlock->bast = NULL;
392 	newlock->astdata = NULL;
393 	newlock->ml.cookie = cpu_to_be64(cookie);
394 	newlock->ast_pending = 0;
395 	newlock->bast_pending = 0;
396 	newlock->convert_pending = 0;
397 	newlock->lock_pending = 0;
398 	newlock->unlock_pending = 0;
399 	newlock->cancel_pending = 0;
400 	newlock->lksb_kernel_allocated = 0;
401 
402 	kref_init(&newlock->lock_refs);
403 }
404 
405 struct dlm_lock * dlm_new_lock(int type, u8 node, u64 cookie,
406 			       struct dlm_lockstatus *lksb)
407 {
408 	struct dlm_lock *lock;
409 	int kernel_allocated = 0;
410 
411 	lock = kcalloc(1, sizeof(*lock), GFP_NOFS);
412 	if (!lock)
413 		return NULL;
414 
415 	if (!lksb) {
416 		/* zero memory only if kernel-allocated */
417 		lksb = kcalloc(1, sizeof(*lksb), GFP_NOFS);
418 		if (!lksb) {
419 			kfree(lock);
420 			return NULL;
421 		}
422 		kernel_allocated = 1;
423 	}
424 
425 	dlm_init_lock(lock, type, node, cookie);
426 	if (kernel_allocated)
427 		lock->lksb_kernel_allocated = 1;
428 	lock->lksb = lksb;
429 	lksb->lockid = lock;
430 	return lock;
431 }
432 
433 /* handler for lock creation net message
434  * locking:
435  *   caller needs:  none
436  *   taken:         takes and drops res->spinlock
437  *   held on exit:  none
438  * returns: DLM_NORMAL, DLM_SYSERR, DLM_IVLOCKID, DLM_NOTQUEUED
439  */
440 int dlm_create_lock_handler(struct o2net_msg *msg, u32 len, void *data)
441 {
442 	struct dlm_ctxt *dlm = data;
443 	struct dlm_create_lock *create = (struct dlm_create_lock *)msg->buf;
444 	struct dlm_lock_resource *res = NULL;
445 	struct dlm_lock *newlock = NULL;
446 	struct dlm_lockstatus *lksb = NULL;
447 	enum dlm_status status = DLM_NORMAL;
448 	char *name;
449 	unsigned int namelen;
450 
451 	BUG_ON(!dlm);
452 
453 	mlog_entry_void();
454 
455 	if (!dlm_grab(dlm))
456 		return DLM_REJECTED;
457 
458 	name = create->name;
459 	namelen = create->namelen;
460 	status = DLM_REJECTED;
461 	if (!dlm_domain_fully_joined(dlm)) {
462 		mlog(ML_ERROR, "Domain %s not fully joined, but node %u is "
463 		     "sending a create_lock message for lock %.*s!\n",
464 		     dlm->name, create->node_idx, namelen, name);
465 		dlm_error(status);
466 		goto leave;
467 	}
468 
469 	status = DLM_IVBUFLEN;
470 	if (namelen > DLM_LOCKID_NAME_MAX) {
471 		dlm_error(status);
472 		goto leave;
473 	}
474 
475 	status = DLM_SYSERR;
476 	newlock = dlm_new_lock(create->requested_type,
477 			       create->node_idx,
478 			       be64_to_cpu(create->cookie), NULL);
479 	if (!newlock) {
480 		dlm_error(status);
481 		goto leave;
482 	}
483 
484 	lksb = newlock->lksb;
485 
486 	if (be32_to_cpu(create->flags) & LKM_GET_LVB) {
487 		lksb->flags |= DLM_LKSB_GET_LVB;
488 		mlog(0, "set DLM_LKSB_GET_LVB flag\n");
489 	}
490 
491 	status = DLM_IVLOCKID;
492 	res = dlm_lookup_lockres(dlm, name, namelen);
493 	if (!res) {
494 		dlm_error(status);
495 		goto leave;
496 	}
497 
498 	spin_lock(&res->spinlock);
499 	status = __dlm_lockres_state_to_status(res);
500 	spin_unlock(&res->spinlock);
501 
502 	if (status != DLM_NORMAL) {
503 		mlog(0, "lockres recovering/migrating/in-progress\n");
504 		goto leave;
505 	}
506 
507 	dlm_lock_attach_lockres(newlock, res);
508 
509 	status = dlmlock_master(dlm, res, newlock, be32_to_cpu(create->flags));
510 leave:
511 	if (status != DLM_NORMAL)
512 		if (newlock)
513 			dlm_lock_put(newlock);
514 
515 	if (res)
516 		dlm_lockres_put(res);
517 
518 	dlm_put(dlm);
519 
520 	return status;
521 }
522 
523 
524 /* fetch next node-local (u8 nodenum + u56 cookie) into u64 */
525 static inline void dlm_get_next_cookie(u8 node_num, u64 *cookie)
526 {
527 	u64 tmpnode = node_num;
528 
529 	/* shift single byte of node num into top 8 bits */
530 	tmpnode <<= 56;
531 
532 	spin_lock(&dlm_cookie_lock);
533 	*cookie = (dlm_next_cookie | tmpnode);
534 	if (++dlm_next_cookie & 0xff00000000000000ull) {
535 		mlog(0, "This node's cookie will now wrap!\n");
536 		dlm_next_cookie = 1;
537 	}
538 	spin_unlock(&dlm_cookie_lock);
539 }
540 
541 enum dlm_status dlmlock(struct dlm_ctxt *dlm, int mode,
542 			struct dlm_lockstatus *lksb, int flags,
543 			const char *name, dlm_astlockfunc_t *ast, void *data,
544 			dlm_bastlockfunc_t *bast)
545 {
546 	enum dlm_status status;
547 	struct dlm_lock_resource *res = NULL;
548 	struct dlm_lock *lock = NULL;
549 	int convert = 0, recovery = 0;
550 
551 	/* yes this function is a mess.
552 	 * TODO: clean this up.  lots of common code in the
553 	 *       lock and convert paths, especially in the retry blocks */
554 	if (!lksb) {
555 		dlm_error(DLM_BADARGS);
556 		return DLM_BADARGS;
557 	}
558 
559 	status = DLM_BADPARAM;
560 	if (mode != LKM_EXMODE && mode != LKM_PRMODE && mode != LKM_NLMODE) {
561 		dlm_error(status);
562 		goto error;
563 	}
564 
565 	if (flags & ~LKM_VALID_FLAGS) {
566 		dlm_error(status);
567 		goto error;
568 	}
569 
570 	convert = (flags & LKM_CONVERT);
571 	recovery = (flags & LKM_RECOVERY);
572 
573 	if (recovery &&
574 	    (!dlm_is_recovery_lock(name, strlen(name)) || convert) ) {
575 		dlm_error(status);
576 		goto error;
577 	}
578 	if (convert && (flags & LKM_LOCAL)) {
579 		mlog(ML_ERROR, "strange LOCAL convert request!\n");
580 		goto error;
581 	}
582 
583 	if (convert) {
584 		/* CONVERT request */
585 
586 		/* if converting, must pass in a valid dlm_lock */
587 		lock = lksb->lockid;
588 		if (!lock) {
589 			mlog(ML_ERROR, "NULL lock pointer in convert "
590 			     "request\n");
591 			goto error;
592 		}
593 
594 		res = lock->lockres;
595 		if (!res) {
596 			mlog(ML_ERROR, "NULL lockres pointer in convert "
597 			     "request\n");
598 			goto error;
599 		}
600 		dlm_lockres_get(res);
601 
602 		/* XXX: for ocfs2 purposes, the ast/bast/astdata/lksb are
603 	 	 * static after the original lock call.  convert requests will
604 		 * ensure that everything is the same, or return DLM_BADARGS.
605 	 	 * this means that DLM_DENIED_NOASTS will never be returned.
606 	 	 */
607 		if (lock->lksb != lksb || lock->ast != ast ||
608 		    lock->bast != bast || lock->astdata != data) {
609 			status = DLM_BADARGS;
610 			mlog(ML_ERROR, "new args:  lksb=%p, ast=%p, bast=%p, "
611 			     "astdata=%p\n", lksb, ast, bast, data);
612 			mlog(ML_ERROR, "orig args: lksb=%p, ast=%p, bast=%p, "
613 			     "astdata=%p\n", lock->lksb, lock->ast,
614 			     lock->bast, lock->astdata);
615 			goto error;
616 		}
617 retry_convert:
618 		dlm_wait_for_recovery(dlm);
619 
620 		if (res->owner == dlm->node_num)
621 			status = dlmconvert_master(dlm, res, lock, flags, mode);
622 		else
623 			status = dlmconvert_remote(dlm, res, lock, flags, mode);
624 		if (status == DLM_RECOVERING || status == DLM_MIGRATING ||
625 		    status == DLM_FORWARD) {
626 			/* for now, see how this works without sleeping
627 			 * and just retry right away.  I suspect the reco
628 			 * or migration will complete fast enough that
629 			 * no waiting will be necessary */
630 			mlog(0, "retrying convert with migration/recovery/"
631 			     "in-progress\n");
632 			msleep(100);
633 			goto retry_convert;
634 		}
635 	} else {
636 		u64 tmpcookie;
637 
638 		/* LOCK request */
639 		status = DLM_BADARGS;
640 		if (!name) {
641 			dlm_error(status);
642 			goto error;
643 		}
644 
645 		status = DLM_IVBUFLEN;
646 		if (strlen(name) > DLM_LOCKID_NAME_MAX || strlen(name) < 1) {
647 			dlm_error(status);
648 			goto error;
649 		}
650 
651 		dlm_get_next_cookie(dlm->node_num, &tmpcookie);
652 		lock = dlm_new_lock(mode, dlm->node_num, tmpcookie, lksb);
653 		if (!lock) {
654 			dlm_error(status);
655 			goto error;
656 		}
657 
658 		if (!recovery)
659 			dlm_wait_for_recovery(dlm);
660 
661 		/* find or create the lock resource */
662 		res = dlm_get_lock_resource(dlm, name, flags);
663 		if (!res) {
664 			status = DLM_IVLOCKID;
665 			dlm_error(status);
666 			goto error;
667 		}
668 
669 		mlog(0, "type=%d, flags = 0x%x\n", mode, flags);
670 		mlog(0, "creating lock: lock=%p res=%p\n", lock, res);
671 
672 		dlm_lock_attach_lockres(lock, res);
673 		lock->ast = ast;
674 		lock->bast = bast;
675 		lock->astdata = data;
676 
677 retry_lock:
678 		if (flags & LKM_VALBLK) {
679 			mlog(0, "LKM_VALBLK passed by caller\n");
680 
681 			/* LVB requests for non PR, PW or EX locks are
682 			 * ignored. */
683 			if (mode < LKM_PRMODE)
684 				flags &= ~LKM_VALBLK;
685 			else {
686 				flags |= LKM_GET_LVB;
687 				lock->lksb->flags |= DLM_LKSB_GET_LVB;
688 			}
689 		}
690 
691 		if (res->owner == dlm->node_num)
692 			status = dlmlock_master(dlm, res, lock, flags);
693 		else
694 			status = dlmlock_remote(dlm, res, lock, flags);
695 
696 		if (status == DLM_RECOVERING || status == DLM_MIGRATING ||
697 		    status == DLM_FORWARD) {
698 			mlog(0, "retrying lock with migration/"
699 			     "recovery/in progress\n");
700 			msleep(100);
701 			/* no waiting for dlm_reco_thread */
702 			if (recovery) {
703 				if (status != DLM_RECOVERING)
704 					goto retry_lock;
705 
706 				mlog(0, "%s: got RECOVERING "
707 				     "for $RECOVERY lock, master "
708 				     "was %u\n", dlm->name,
709 				     res->owner);
710 				/* wait to see the node go down, then
711 				 * drop down and allow the lockres to
712 				 * get cleaned up.  need to remaster. */
713 				dlm_wait_for_node_death(dlm, res->owner,
714 						DLM_NODE_DEATH_WAIT_MAX);
715 			} else {
716 				dlm_wait_for_recovery(dlm);
717 				goto retry_lock;
718 			}
719 		}
720 
721 		if (status != DLM_NORMAL) {
722 			lock->lksb->flags &= ~DLM_LKSB_GET_LVB;
723 			if (status != DLM_NOTQUEUED)
724 				dlm_error(status);
725 			goto error;
726 		}
727 	}
728 
729 error:
730 	if (status != DLM_NORMAL) {
731 		if (lock && !convert)
732 			dlm_lock_put(lock);
733 		// this is kind of unnecessary
734 		lksb->status = status;
735 	}
736 
737 	/* put lockres ref from the convert path
738 	 * or from dlm_get_lock_resource */
739 	if (res)
740 		dlm_lockres_put(res);
741 
742 	return status;
743 }
744 EXPORT_SYMBOL_GPL(dlmlock);
745