xref: /linux/fs/ocfs2/dlm/dlmunlock.c (revision f3d9478b2ce468c3115b02ecae7e975990697f15)
1 /* -*- mode: c; c-basic-offset: 8; -*-
2  * vim: noexpandtab sw=8 ts=8 sts=0:
3  *
4  * dlmunlock.c
5  *
6  * underlying calls for unlocking locks
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 #include "cluster/heartbeat.h"
44 #include "cluster/nodemanager.h"
45 #include "cluster/tcp.h"
46 
47 #include "dlmapi.h"
48 #include "dlmcommon.h"
49 
50 #define MLOG_MASK_PREFIX ML_DLM
51 #include "cluster/masklog.h"
52 
53 #define DLM_UNLOCK_FREE_LOCK           0x00000001
54 #define DLM_UNLOCK_CALL_AST            0x00000002
55 #define DLM_UNLOCK_REMOVE_LOCK         0x00000004
56 #define DLM_UNLOCK_REGRANT_LOCK        0x00000008
57 #define DLM_UNLOCK_CLEAR_CONVERT_TYPE  0x00000010
58 
59 
60 static enum dlm_status dlm_get_cancel_actions(struct dlm_ctxt *dlm,
61 					      struct dlm_lock_resource *res,
62 					      struct dlm_lock *lock,
63 					      struct dlm_lockstatus *lksb,
64 					      int *actions);
65 static enum dlm_status dlm_get_unlock_actions(struct dlm_ctxt *dlm,
66 					      struct dlm_lock_resource *res,
67 					      struct dlm_lock *lock,
68 					      struct dlm_lockstatus *lksb,
69 					      int *actions);
70 
71 static enum dlm_status dlm_send_remote_unlock_request(struct dlm_ctxt *dlm,
72 						 struct dlm_lock_resource *res,
73 						 struct dlm_lock *lock,
74 						 struct dlm_lockstatus *lksb,
75 						 int flags,
76 						 u8 owner);
77 
78 
79 /*
80  * according to the spec:
81  * http://opendlm.sourceforge.net/cvsmirror/opendlm/docs/dlmbook_final.pdf
82  *
83  *  flags & LKM_CANCEL != 0: must be converting or blocked
84  *  flags & LKM_CANCEL == 0: must be granted
85  *
86  * So to unlock a converting lock, you must first cancel the
87  * convert (passing LKM_CANCEL in flags), then call the unlock
88  * again (with no LKM_CANCEL in flags).
89  */
90 
91 
92 /*
93  * locking:
94  *   caller needs:  none
95  *   taken:         res->spinlock and lock->spinlock taken and dropped
96  *   held on exit:  none
97  * returns: DLM_NORMAL, DLM_NOLOCKMGR, status from network
98  * all callers should have taken an extra ref on lock coming in
99  */
100 static enum dlm_status dlmunlock_common(struct dlm_ctxt *dlm,
101 					struct dlm_lock_resource *res,
102 					struct dlm_lock *lock,
103 					struct dlm_lockstatus *lksb,
104 					int flags, int *call_ast,
105 					int master_node)
106 {
107 	enum dlm_status status;
108 	int actions = 0;
109 	int in_use;
110         u8 owner;
111 
112 	mlog(0, "master_node = %d, valblk = %d\n", master_node,
113 	     flags & LKM_VALBLK);
114 
115 	if (master_node)
116 		BUG_ON(res->owner != dlm->node_num);
117 	else
118 		BUG_ON(res->owner == dlm->node_num);
119 
120 	spin_lock(&dlm->spinlock);
121 	/* We want to be sure that we're not freeing a lock
122 	 * that still has AST's pending... */
123 	in_use = !list_empty(&lock->ast_list);
124 	spin_unlock(&dlm->spinlock);
125 	if (in_use) {
126 	       mlog(ML_ERROR, "lockres %.*s: Someone is calling dlmunlock "
127 		    "while waiting for an ast!", res->lockname.len,
128 		    res->lockname.name);
129 		return DLM_BADPARAM;
130 	}
131 
132 	spin_lock(&res->spinlock);
133 	if (res->state & DLM_LOCK_RES_IN_PROGRESS) {
134 		if (master_node) {
135 			mlog(ML_ERROR, "lockres in progress!\n");
136 			spin_unlock(&res->spinlock);
137 			return DLM_FORWARD;
138 		}
139 		/* ok for this to sleep if not in a network handler */
140 		__dlm_wait_on_lockres(res);
141 		res->state |= DLM_LOCK_RES_IN_PROGRESS;
142 	}
143 	spin_lock(&lock->spinlock);
144 
145 	if (res->state & DLM_LOCK_RES_RECOVERING) {
146 		status = DLM_RECOVERING;
147 		goto leave;
148 	}
149 
150 
151 	/* see above for what the spec says about
152 	 * LKM_CANCEL and the lock queue state */
153 	if (flags & LKM_CANCEL)
154 		status = dlm_get_cancel_actions(dlm, res, lock, lksb, &actions);
155 	else
156 		status = dlm_get_unlock_actions(dlm, res, lock, lksb, &actions);
157 
158 	if (status != DLM_NORMAL)
159 		goto leave;
160 
161 	/* By now this has been masked out of cancel requests. */
162 	if (flags & LKM_VALBLK) {
163 		/* make the final update to the lvb */
164 		if (master_node)
165 			memcpy(res->lvb, lksb->lvb, DLM_LVB_LEN);
166 		else
167 			flags |= LKM_PUT_LVB; /* let the send function
168 					       * handle it. */
169 	}
170 
171 	if (!master_node) {
172 		owner = res->owner;
173 		/* drop locks and send message */
174 		if (flags & LKM_CANCEL)
175 			lock->cancel_pending = 1;
176 		else
177 			lock->unlock_pending = 1;
178 		spin_unlock(&lock->spinlock);
179 		spin_unlock(&res->spinlock);
180 		status = dlm_send_remote_unlock_request(dlm, res, lock, lksb,
181 							flags, owner);
182 		spin_lock(&res->spinlock);
183 		spin_lock(&lock->spinlock);
184 		/* if the master told us the lock was already granted,
185 		 * let the ast handle all of these actions */
186 		if (status == DLM_NORMAL &&
187 		    lksb->status == DLM_CANCELGRANT) {
188 			actions &= ~(DLM_UNLOCK_REMOVE_LOCK|
189 				     DLM_UNLOCK_REGRANT_LOCK|
190 				     DLM_UNLOCK_CLEAR_CONVERT_TYPE);
191 		} else if (status == DLM_RECOVERING ||
192 			   status == DLM_MIGRATING ||
193 			   status == DLM_FORWARD) {
194 			/* must clear the actions because this unlock
195 			 * is about to be retried.  cannot free or do
196 			 * any list manipulation. */
197 			mlog(0, "%s:%.*s: clearing actions, %s\n",
198 			     dlm->name, res->lockname.len,
199 			     res->lockname.name,
200 			     status==DLM_RECOVERING?"recovering":
201 			     (status==DLM_MIGRATING?"migrating":
202 			      "forward"));
203 			actions = 0;
204 		}
205 		if (flags & LKM_CANCEL)
206 			lock->cancel_pending = 0;
207 		else
208 			lock->unlock_pending = 0;
209 
210 	}
211 
212 	/* get an extra ref on lock.  if we are just switching
213 	 * lists here, we dont want the lock to go away. */
214 	dlm_lock_get(lock);
215 
216 	if (actions & DLM_UNLOCK_REMOVE_LOCK) {
217 		list_del_init(&lock->list);
218 		dlm_lock_put(lock);
219 	}
220 	if (actions & DLM_UNLOCK_REGRANT_LOCK) {
221 		dlm_lock_get(lock);
222 		list_add_tail(&lock->list, &res->granted);
223 	}
224 	if (actions & DLM_UNLOCK_CLEAR_CONVERT_TYPE) {
225 		mlog(0, "clearing convert_type at %smaster node\n",
226 		     master_node ? "" : "non-");
227 		lock->ml.convert_type = LKM_IVMODE;
228 	}
229 
230 	/* remove the extra ref on lock */
231 	dlm_lock_put(lock);
232 
233 leave:
234 	res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
235 	if (!dlm_lock_on_list(&res->converting, lock))
236 		BUG_ON(lock->ml.convert_type != LKM_IVMODE);
237 	else
238 		BUG_ON(lock->ml.convert_type == LKM_IVMODE);
239 	spin_unlock(&lock->spinlock);
240 	spin_unlock(&res->spinlock);
241 	wake_up(&res->wq);
242 
243 	/* let the caller's final dlm_lock_put handle the actual kfree */
244 	if (actions & DLM_UNLOCK_FREE_LOCK) {
245 		/* this should always be coupled with list removal */
246 		BUG_ON(!(actions & DLM_UNLOCK_REMOVE_LOCK));
247 		mlog(0, "lock %u:%llu should be gone now! refs=%d\n",
248 		     dlm_get_lock_cookie_node(lock->ml.cookie),
249 		     dlm_get_lock_cookie_seq(lock->ml.cookie),
250 		     atomic_read(&lock->lock_refs.refcount)-1);
251 		dlm_lock_put(lock);
252 	}
253 	if (actions & DLM_UNLOCK_CALL_AST)
254 		*call_ast = 1;
255 
256 	/* if cancel or unlock succeeded, lvb work is done */
257 	if (status == DLM_NORMAL)
258 		lksb->flags &= ~(DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB);
259 
260 	return status;
261 }
262 
263 void dlm_commit_pending_unlock(struct dlm_lock_resource *res,
264 			       struct dlm_lock *lock)
265 {
266 	/* leave DLM_LKSB_PUT_LVB on the lksb so any final
267 	 * update of the lvb will be sent to the new master */
268 	list_del_init(&lock->list);
269 }
270 
271 void dlm_commit_pending_cancel(struct dlm_lock_resource *res,
272 			       struct dlm_lock *lock)
273 {
274 	list_del_init(&lock->list);
275 	list_add_tail(&lock->list, &res->granted);
276 	lock->ml.convert_type = LKM_IVMODE;
277 }
278 
279 
280 static inline enum dlm_status dlmunlock_master(struct dlm_ctxt *dlm,
281 					  struct dlm_lock_resource *res,
282 					  struct dlm_lock *lock,
283 					  struct dlm_lockstatus *lksb,
284 					  int flags,
285 					  int *call_ast)
286 {
287 	return dlmunlock_common(dlm, res, lock, lksb, flags, call_ast, 1);
288 }
289 
290 static inline enum dlm_status dlmunlock_remote(struct dlm_ctxt *dlm,
291 					  struct dlm_lock_resource *res,
292 					  struct dlm_lock *lock,
293 					  struct dlm_lockstatus *lksb,
294 					  int flags, int *call_ast)
295 {
296 	return dlmunlock_common(dlm, res, lock, lksb, flags, call_ast, 0);
297 }
298 
299 /*
300  * locking:
301  *   caller needs:  none
302  *   taken:         none
303  *   held on exit:  none
304  * returns: DLM_NORMAL, DLM_NOLOCKMGR, status from network
305  */
306 static enum dlm_status dlm_send_remote_unlock_request(struct dlm_ctxt *dlm,
307 						 struct dlm_lock_resource *res,
308 						 struct dlm_lock *lock,
309 						 struct dlm_lockstatus *lksb,
310 						 int flags,
311 						 u8 owner)
312 {
313 	struct dlm_unlock_lock unlock;
314 	int tmpret;
315 	enum dlm_status ret;
316 	int status = 0;
317 	struct kvec vec[2];
318 	size_t veclen = 1;
319 
320 	mlog_entry("%.*s\n", res->lockname.len, res->lockname.name);
321 
322 	memset(&unlock, 0, sizeof(unlock));
323 	unlock.node_idx = dlm->node_num;
324 	unlock.flags = cpu_to_be32(flags);
325 	unlock.cookie = lock->ml.cookie;
326 	unlock.namelen = res->lockname.len;
327 	memcpy(unlock.name, res->lockname.name, unlock.namelen);
328 
329 	vec[0].iov_len = sizeof(struct dlm_unlock_lock);
330 	vec[0].iov_base = &unlock;
331 
332 	if (flags & LKM_PUT_LVB) {
333 		/* extra data to send if we are updating lvb */
334 		vec[1].iov_len = DLM_LVB_LEN;
335 		vec[1].iov_base = lock->lksb->lvb;
336 		veclen++;
337 	}
338 
339 	tmpret = o2net_send_message_vec(DLM_UNLOCK_LOCK_MSG, dlm->key,
340 					vec, veclen, owner, &status);
341 	if (tmpret >= 0) {
342 		// successfully sent and received
343 		if (status == DLM_CANCELGRANT)
344 			ret = DLM_NORMAL;
345 		else if (status == DLM_FORWARD) {
346 			mlog(0, "master was in-progress.  retry\n");
347 			ret = DLM_FORWARD;
348 		} else
349 			ret = status;
350 		lksb->status = status;
351 	} else {
352 		mlog_errno(tmpret);
353 		if (dlm_is_host_down(tmpret)) {
354 			/* NOTE: this seems strange, but it is what we want.
355 			 * when the master goes down during a cancel or
356 			 * unlock, the recovery code completes the operation
357 			 * as if the master had not died, then passes the
358 			 * updated state to the recovery master.  this thread
359 			 * just needs to finish out the operation and call
360 			 * the unlockast. */
361 			ret = DLM_NORMAL;
362 		} else {
363 			/* something bad.  this will BUG in ocfs2 */
364 			ret = dlm_err_to_dlm_status(tmpret);
365 		}
366 		lksb->status = ret;
367 	}
368 
369 	return ret;
370 }
371 
372 /*
373  * locking:
374  *   caller needs:  none
375  *   taken:         takes and drops res->spinlock
376  *   held on exit:  none
377  * returns: DLM_NORMAL, DLM_BADARGS, DLM_IVLOCKID,
378  *          return value from dlmunlock_master
379  */
380 int dlm_unlock_lock_handler(struct o2net_msg *msg, u32 len, void *data)
381 {
382 	struct dlm_ctxt *dlm = data;
383 	struct dlm_unlock_lock *unlock = (struct dlm_unlock_lock *)msg->buf;
384 	struct dlm_lock_resource *res = NULL;
385 	struct list_head *iter;
386 	struct dlm_lock *lock = NULL;
387 	enum dlm_status status = DLM_NORMAL;
388 	int found = 0, i;
389 	struct dlm_lockstatus *lksb = NULL;
390 	int ignore;
391 	u32 flags;
392 	struct list_head *queue;
393 
394 	flags = be32_to_cpu(unlock->flags);
395 
396 	if (flags & LKM_GET_LVB) {
397 		mlog(ML_ERROR, "bad args!  GET_LVB specified on unlock!\n");
398 		return DLM_BADARGS;
399 	}
400 
401 	if ((flags & (LKM_PUT_LVB|LKM_CANCEL)) == (LKM_PUT_LVB|LKM_CANCEL)) {
402 		mlog(ML_ERROR, "bad args!  cannot modify lvb on a CANCEL "
403 		     "request!\n");
404 		return DLM_BADARGS;
405 	}
406 
407 	if (unlock->namelen > DLM_LOCKID_NAME_MAX) {
408 		mlog(ML_ERROR, "Invalid name length in unlock handler!\n");
409 		return DLM_IVBUFLEN;
410 	}
411 
412 	if (!dlm_grab(dlm))
413 		return DLM_REJECTED;
414 
415 	mlog_bug_on_msg(!dlm_domain_fully_joined(dlm),
416 			"Domain %s not fully joined!\n", dlm->name);
417 
418 	mlog(0, "lvb: %s\n", flags & LKM_PUT_LVB ? "put lvb" : "none");
419 
420 	res = dlm_lookup_lockres(dlm, unlock->name, unlock->namelen);
421 	if (!res) {
422 		/* We assume here that a no lock resource simply means
423 		 * it was migrated away and destroyed before the other
424 		 * node could detect it. */
425 		mlog(0, "returning DLM_FORWARD -- res no longer exists\n");
426 		status = DLM_FORWARD;
427 		goto not_found;
428 	}
429 
430 	queue=&res->granted;
431 	found = 0;
432 	spin_lock(&res->spinlock);
433 	if (res->state & DLM_LOCK_RES_RECOVERING) {
434 		spin_unlock(&res->spinlock);
435 		mlog(0, "returning DLM_RECOVERING\n");
436 		status = DLM_RECOVERING;
437 		goto leave;
438 	}
439 
440 	if (res->state & DLM_LOCK_RES_MIGRATING) {
441 		spin_unlock(&res->spinlock);
442 		mlog(0, "returning DLM_MIGRATING\n");
443 		status = DLM_MIGRATING;
444 		goto leave;
445 	}
446 
447 	if (res->owner != dlm->node_num) {
448 		spin_unlock(&res->spinlock);
449 		mlog(0, "returning DLM_FORWARD -- not master\n");
450 		status = DLM_FORWARD;
451 		goto leave;
452 	}
453 
454 	for (i=0; i<3; i++) {
455 		list_for_each(iter, queue) {
456 			lock = list_entry(iter, struct dlm_lock, list);
457 			if (lock->ml.cookie == unlock->cookie &&
458 		    	    lock->ml.node == unlock->node_idx) {
459 				dlm_lock_get(lock);
460 				found = 1;
461 				break;
462 			}
463 		}
464 		if (found)
465 			break;
466 		/* scan granted -> converting -> blocked queues */
467 		queue++;
468 	}
469 	spin_unlock(&res->spinlock);
470 	if (!found) {
471 		status = DLM_IVLOCKID;
472 		goto not_found;
473 	}
474 
475 	/* lock was found on queue */
476 	lksb = lock->lksb;
477 	/* unlockast only called on originating node */
478 	if (flags & LKM_PUT_LVB) {
479 		lksb->flags |= DLM_LKSB_PUT_LVB;
480 		memcpy(&lksb->lvb[0], &unlock->lvb[0], DLM_LVB_LEN);
481 	}
482 
483 	/* if this is in-progress, propagate the DLM_FORWARD
484 	 * all the way back out */
485 	status = dlmunlock_master(dlm, res, lock, lksb, flags, &ignore);
486 	if (status == DLM_FORWARD)
487 		mlog(0, "lockres is in progress\n");
488 
489 	if (flags & LKM_PUT_LVB)
490 		lksb->flags &= ~DLM_LKSB_PUT_LVB;
491 
492 	dlm_lockres_calc_usage(dlm, res);
493 	dlm_kick_thread(dlm, res);
494 
495 not_found:
496 	if (!found)
497 		mlog(ML_ERROR, "failed to find lock to unlock! "
498 			       "cookie=%u:%llu\n",
499 			       dlm_get_lock_cookie_node(unlock->cookie),
500 			       dlm_get_lock_cookie_seq(unlock->cookie));
501 	else {
502 		/* send the lksb->status back to the other node */
503 		status = lksb->status;
504 		dlm_lock_put(lock);
505 	}
506 
507 leave:
508 	if (res)
509 		dlm_lockres_put(res);
510 
511 	dlm_put(dlm);
512 
513 	return status;
514 }
515 
516 
517 static enum dlm_status dlm_get_cancel_actions(struct dlm_ctxt *dlm,
518 					      struct dlm_lock_resource *res,
519 					      struct dlm_lock *lock,
520 					      struct dlm_lockstatus *lksb,
521 					      int *actions)
522 {
523 	enum dlm_status status;
524 
525 	if (dlm_lock_on_list(&res->blocked, lock)) {
526 		/* cancel this outright */
527 		lksb->status = DLM_NORMAL;
528 		status = DLM_NORMAL;
529 		*actions = (DLM_UNLOCK_CALL_AST |
530 			    DLM_UNLOCK_REMOVE_LOCK);
531 	} else if (dlm_lock_on_list(&res->converting, lock)) {
532 		/* cancel the request, put back on granted */
533 		lksb->status = DLM_NORMAL;
534 		status = DLM_NORMAL;
535 		*actions = (DLM_UNLOCK_CALL_AST |
536 			    DLM_UNLOCK_REMOVE_LOCK |
537 			    DLM_UNLOCK_REGRANT_LOCK |
538 			    DLM_UNLOCK_CLEAR_CONVERT_TYPE);
539 	} else if (dlm_lock_on_list(&res->granted, lock)) {
540 		/* too late, already granted.  DLM_CANCELGRANT */
541 		lksb->status = DLM_CANCELGRANT;
542 		status = DLM_NORMAL;
543 		*actions = DLM_UNLOCK_CALL_AST;
544 	} else {
545 		mlog(ML_ERROR, "lock to cancel is not on any list!\n");
546 		lksb->status = DLM_IVLOCKID;
547 		status = DLM_IVLOCKID;
548 		*actions = 0;
549 	}
550 	return status;
551 }
552 
553 static enum dlm_status dlm_get_unlock_actions(struct dlm_ctxt *dlm,
554 					      struct dlm_lock_resource *res,
555 					      struct dlm_lock *lock,
556 					      struct dlm_lockstatus *lksb,
557 					      int *actions)
558 {
559 	enum dlm_status status;
560 
561 	/* unlock request */
562 	if (!dlm_lock_on_list(&res->granted, lock)) {
563 		lksb->status = DLM_DENIED;
564 		status = DLM_DENIED;
565 		dlm_error(status);
566 		*actions = 0;
567 	} else {
568 		/* unlock granted lock */
569 		lksb->status = DLM_NORMAL;
570 		status = DLM_NORMAL;
571 		*actions = (DLM_UNLOCK_FREE_LOCK |
572 			    DLM_UNLOCK_CALL_AST |
573 			    DLM_UNLOCK_REMOVE_LOCK);
574 	}
575 	return status;
576 }
577 
578 /* there seems to be no point in doing this async
579  * since (even for the remote case) there is really
580  * no work to queue up... so just do it and fire the
581  * unlockast by hand when done... */
582 enum dlm_status dlmunlock(struct dlm_ctxt *dlm, struct dlm_lockstatus *lksb,
583 			  int flags, dlm_astunlockfunc_t *unlockast, void *data)
584 {
585 	enum dlm_status status;
586 	struct dlm_lock_resource *res;
587 	struct dlm_lock *lock = NULL;
588 	int call_ast, is_master;
589 
590 	mlog_entry_void();
591 
592 	if (!lksb) {
593 		dlm_error(DLM_BADARGS);
594 		return DLM_BADARGS;
595 	}
596 
597 	if (flags & ~(LKM_CANCEL | LKM_VALBLK | LKM_INVVALBLK)) {
598 		dlm_error(DLM_BADPARAM);
599 		return DLM_BADPARAM;
600 	}
601 
602 	if ((flags & (LKM_VALBLK | LKM_CANCEL)) == (LKM_VALBLK | LKM_CANCEL)) {
603 		mlog(0, "VALBLK given with CANCEL: ignoring VALBLK\n");
604 		flags &= ~LKM_VALBLK;
605 	}
606 
607 	if (!lksb->lockid || !lksb->lockid->lockres) {
608 		dlm_error(DLM_BADPARAM);
609 		return DLM_BADPARAM;
610 	}
611 
612 	lock = lksb->lockid;
613 	BUG_ON(!lock);
614 	dlm_lock_get(lock);
615 
616 	res = lock->lockres;
617 	BUG_ON(!res);
618 	dlm_lockres_get(res);
619 retry:
620 	call_ast = 0;
621 	/* need to retry up here because owner may have changed */
622 	mlog(0, "lock=%p res=%p\n", lock, res);
623 
624 	spin_lock(&res->spinlock);
625 	is_master = (res->owner == dlm->node_num);
626 	spin_unlock(&res->spinlock);
627 
628 	if (is_master) {
629 		status = dlmunlock_master(dlm, res, lock, lksb, flags,
630 					  &call_ast);
631 		mlog(0, "done calling dlmunlock_master: returned %d, "
632 		     "call_ast is %d\n", status, call_ast);
633 	} else {
634 		status = dlmunlock_remote(dlm, res, lock, lksb, flags,
635 					  &call_ast);
636 		mlog(0, "done calling dlmunlock_remote: returned %d, "
637 		     "call_ast is %d\n", status, call_ast);
638 	}
639 
640 	if (status == DLM_RECOVERING ||
641 	    status == DLM_MIGRATING ||
642 	    status == DLM_FORWARD) {
643 		/* We want to go away for a tiny bit to allow recovery
644 		 * / migration to complete on this resource. I don't
645 		 * know of any wait queue we could sleep on as this
646 		 * may be happening on another node. Perhaps the
647 		 * proper solution is to queue up requests on the
648 		 * other end? */
649 
650 		/* do we want to yield(); ?? */
651 		msleep(50);
652 
653 		mlog(0, "retrying unlock due to pending recovery/"
654 		     "migration/in-progress\n");
655 		goto retry;
656 	}
657 
658 	if (call_ast) {
659 		mlog(0, "calling unlockast(%p, %d)\n", data, lksb->status);
660 		if (is_master) {
661 			/* it is possible that there is one last bast
662 			 * pending.  make sure it is flushed, then
663 			 * call the unlockast.
664 			 * not an issue if this is a mastered remotely,
665 			 * since this lock has been removed from the
666 			 * lockres queues and cannot be found. */
667 			dlm_kick_thread(dlm, NULL);
668 			wait_event(dlm->ast_wq,
669 				   dlm_lock_basts_flushed(dlm, lock));
670 		}
671 		(*unlockast)(data, lksb->status);
672 	}
673 
674 	if (status == DLM_NORMAL) {
675 		mlog(0, "kicking the thread\n");
676 		dlm_kick_thread(dlm, res);
677 	} else
678 		dlm_error(status);
679 
680 	dlm_lockres_calc_usage(dlm, res);
681 	dlm_lockres_put(res);
682 	dlm_lock_put(lock);
683 
684 	mlog(0, "returning status=%d!\n", status);
685 	return status;
686 }
687 EXPORT_SYMBOL_GPL(dlmunlock);
688 
689