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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/highmem.h>
32#include <linux/init.h>
33#include <linux/sysctl.h>
34#include <linux/random.h>
35#include <linux/blkdev.h>
36#include <linux/socket.h>
37#include <linux/inet.h>
38#include <linux/spinlock.h>
39#include <linux/delay.h>
40
41#include "cluster/heartbeat.h"
42#include "cluster/nodemanager.h"
43#include "cluster/tcp.h"
44
45#include "dlmapi.h"
46#include "dlmcommon.h"
47
48#define MLOG_MASK_PREFIX ML_DLM
49#include "cluster/masklog.h"
50
51#define DLM_UNLOCK_FREE_LOCK           0x00000001
52#define DLM_UNLOCK_CALL_AST            0x00000002
53#define DLM_UNLOCK_REMOVE_LOCK         0x00000004
54#define DLM_UNLOCK_REGRANT_LOCK        0x00000008
55#define DLM_UNLOCK_CLEAR_CONVERT_TYPE  0x00000010
56
57
58static enum dlm_status dlm_get_cancel_actions(struct dlm_ctxt *dlm,
59					      struct dlm_lock_resource *res,
60					      struct dlm_lock *lock,
61					      struct dlm_lockstatus *lksb,
62					      int *actions);
63static enum dlm_status dlm_get_unlock_actions(struct dlm_ctxt *dlm,
64					      struct dlm_lock_resource *res,
65					      struct dlm_lock *lock,
66					      struct dlm_lockstatus *lksb,
67					      int *actions);
68
69static enum dlm_status dlm_send_remote_unlock_request(struct dlm_ctxt *dlm,
70						 struct dlm_lock_resource *res,
71						 struct dlm_lock *lock,
72						 struct dlm_lockstatus *lksb,
73						 int flags,
74						 u8 owner);
75
76
77/*
78 * according to the spec:
79 * http://opendlm.sourceforge.net/cvsmirror/opendlm/docs/dlmbook_final.pdf
80 *
81 *  flags & LKM_CANCEL != 0: must be converting or blocked
82 *  flags & LKM_CANCEL == 0: must be granted
83 *
84 * So to unlock a converting lock, you must first cancel the
85 * convert (passing LKM_CANCEL in flags), then call the unlock
86 * again (with no LKM_CANCEL in flags).
87 */
88
89
90/*
91 * locking:
92 *   caller needs:  none
93 *   taken:         res->spinlock and lock->spinlock taken and dropped
94 *   held on exit:  none
95 * returns: DLM_NORMAL, DLM_NOLOCKMGR, status from network
96 * all callers should have taken an extra ref on lock coming in
97 */
98static enum dlm_status dlmunlock_common(struct dlm_ctxt *dlm,
99					struct dlm_lock_resource *res,
100					struct dlm_lock *lock,
101					struct dlm_lockstatus *lksb,
102					int flags, int *call_ast,
103					int master_node)
104{
105	enum dlm_status status;
106	int actions = 0;
107	int in_use;
108        u8 owner;
109
110	mlog(0, "master_node = %d, valblk = %d\n", master_node,
111	     flags & LKM_VALBLK);
112
113	if (master_node)
114		BUG_ON(res->owner != dlm->node_num);
115	else
116		BUG_ON(res->owner == dlm->node_num);
117
118	spin_lock(&dlm->ast_lock);
119	/* We want to be sure that we're not freeing a lock
120	 * that still has AST's pending... */
121	in_use = !list_empty(&lock->ast_list);
122	spin_unlock(&dlm->ast_lock);
123	if (in_use && !(flags & LKM_CANCEL)) {
124	       mlog(ML_ERROR, "lockres %.*s: Someone is calling dlmunlock "
125		    "while waiting for an ast!", res->lockname.len,
126		    res->lockname.name);
127		return DLM_BADPARAM;
128	}
129
130	spin_lock(&res->spinlock);
131	if (res->state & DLM_LOCK_RES_IN_PROGRESS) {
132		if (master_node && !(flags & LKM_CANCEL)) {
133			mlog(ML_ERROR, "lockres in progress!\n");
134			spin_unlock(&res->spinlock);
135			return DLM_FORWARD;
136		}
137		/* ok for this to sleep if not in a network handler */
138		__dlm_wait_on_lockres(res);
139		res->state |= DLM_LOCK_RES_IN_PROGRESS;
140	}
141	spin_lock(&lock->spinlock);
142
143	if (res->state & DLM_LOCK_RES_RECOVERING) {
144		status = DLM_RECOVERING;
145		goto leave;
146	}
147
148	if (res->state & DLM_LOCK_RES_MIGRATING) {
149		status = DLM_MIGRATING;
150		goto leave;
151	}
152
153	/* see above for what the spec says about
154	 * LKM_CANCEL and the lock queue state */
155	if (flags & LKM_CANCEL)
156		status = dlm_get_cancel_actions(dlm, res, lock, lksb, &actions);
157	else
158		status = dlm_get_unlock_actions(dlm, res, lock, lksb, &actions);
159
160	if (status != DLM_NORMAL && (status != DLM_CANCELGRANT || !master_node))
161		goto leave;
162
163	/* By now this has been masked out of cancel requests. */
164	if (flags & LKM_VALBLK) {
165		/* make the final update to the lvb */
166		if (master_node)
167			memcpy(res->lvb, lksb->lvb, DLM_LVB_LEN);
168		else
169			flags |= LKM_PUT_LVB; /* let the send function
170					       * handle it. */
171	}
172
173	if (!master_node) {
174		owner = res->owner;
175		/* drop locks and send message */
176		if (flags & LKM_CANCEL)
177			lock->cancel_pending = 1;
178		else
179			lock->unlock_pending = 1;
180		spin_unlock(&lock->spinlock);
181		spin_unlock(&res->spinlock);
182		status = dlm_send_remote_unlock_request(dlm, res, lock, lksb,
183							flags, owner);
184		spin_lock(&res->spinlock);
185		spin_lock(&lock->spinlock);
186		/* if the master told us the lock was already granted,
187		 * let the ast handle all of these actions */
188		if (status == DLM_CANCELGRANT) {
189			actions &= ~(DLM_UNLOCK_REMOVE_LOCK|
190				     DLM_UNLOCK_REGRANT_LOCK|
191				     DLM_UNLOCK_CLEAR_CONVERT_TYPE);
192		} else if (status == DLM_RECOVERING ||
193			   status == DLM_MIGRATING ||
194			   status == DLM_FORWARD) {
195			/* must clear the actions because this unlock
196			 * is about to be retried.  cannot free or do
197			 * any list manipulation. */
198			mlog(0, "%s:%.*s: clearing actions, %s\n",
199			     dlm->name, res->lockname.len,
200			     res->lockname.name,
201			     status==DLM_RECOVERING?"recovering":
202			     (status==DLM_MIGRATING?"migrating":
203			      "forward"));
204			actions = 0;
205		}
206		if (flags & LKM_CANCEL)
207			lock->cancel_pending = 0;
208		else
209			lock->unlock_pending = 0;
210
211	}
212
213	/* get an extra ref on lock.  if we are just switching
214	 * lists here, we dont want the lock to go away. */
215	dlm_lock_get(lock);
216
217	if (actions & DLM_UNLOCK_REMOVE_LOCK) {
218		list_del_init(&lock->list);
219		dlm_lock_put(lock);
220	}
221	if (actions & DLM_UNLOCK_REGRANT_LOCK) {
222		dlm_lock_get(lock);
223		list_add_tail(&lock->list, &res->granted);
224	}
225	if (actions & DLM_UNLOCK_CLEAR_CONVERT_TYPE) {
226		mlog(0, "clearing convert_type at %smaster node\n",
227		     master_node ? "" : "non-");
228		lock->ml.convert_type = LKM_IVMODE;
229	}
230
231	/* remove the extra ref on lock */
232	dlm_lock_put(lock);
233
234leave:
235	res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
236	if (!dlm_lock_on_list(&res->converting, lock))
237		BUG_ON(lock->ml.convert_type != LKM_IVMODE);
238	else
239		BUG_ON(lock->ml.convert_type == LKM_IVMODE);
240	spin_unlock(&lock->spinlock);
241	spin_unlock(&res->spinlock);
242	wake_up(&res->wq);
243
244	/* let the caller's final dlm_lock_put handle the actual kfree */
245	if (actions & DLM_UNLOCK_FREE_LOCK) {
246		/* this should always be coupled with list removal */
247		BUG_ON(!(actions & DLM_UNLOCK_REMOVE_LOCK));
248		mlog(0, "lock %u:%llu should be gone now! refs=%d\n",
249		     dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
250		     dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
251		     atomic_read(&lock->lock_refs.refcount)-1);
252		dlm_lock_put(lock);
253	}
254	if (actions & DLM_UNLOCK_CALL_AST)
255		*call_ast = 1;
256
257	/* if cancel or unlock succeeded, lvb work is done */
258	if (status == DLM_NORMAL)
259		lksb->flags &= ~(DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB);
260
261	return status;
262}
263
264void dlm_commit_pending_unlock(struct dlm_lock_resource *res,
265			       struct dlm_lock *lock)
266{
267	/* leave DLM_LKSB_PUT_LVB on the lksb so any final
268	 * update of the lvb will be sent to the new master */
269	list_del_init(&lock->list);
270}
271
272void dlm_commit_pending_cancel(struct dlm_lock_resource *res,
273			       struct dlm_lock *lock)
274{
275	list_move_tail(&lock->list, &res->granted);
276	lock->ml.convert_type = LKM_IVMODE;
277}
278
279
280static 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
290static 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 */
306static 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	if (owner == dlm->node_num) {
323		/* ended up trying to contact ourself.  this means
324		 * that the lockres had been remote but became local
325		 * via a migration.  just retry it, now as local */
326		mlog(0, "%s:%.*s: this node became the master due to a "
327		     "migration, re-evaluate now\n", dlm->name,
328		     res->lockname.len, res->lockname.name);
329		return DLM_FORWARD;
330	}
331
332	memset(&unlock, 0, sizeof(unlock));
333	unlock.node_idx = dlm->node_num;
334	unlock.flags = cpu_to_be32(flags);
335	unlock.cookie = lock->ml.cookie;
336	unlock.namelen = res->lockname.len;
337	memcpy(unlock.name, res->lockname.name, unlock.namelen);
338
339	vec[0].iov_len = sizeof(struct dlm_unlock_lock);
340	vec[0].iov_base = &unlock;
341
342	if (flags & LKM_PUT_LVB) {
343		/* extra data to send if we are updating lvb */
344		vec[1].iov_len = DLM_LVB_LEN;
345		vec[1].iov_base = lock->lksb->lvb;
346		veclen++;
347	}
348
349	tmpret = o2net_send_message_vec(DLM_UNLOCK_LOCK_MSG, dlm->key,
350					vec, veclen, owner, &status);
351	if (tmpret >= 0) {
352		// successfully sent and received
353		if (status == DLM_FORWARD)
354			mlog(0, "master was in-progress.  retry\n");
355		ret = status;
356	} else {
357		mlog(ML_ERROR, "Error %d when sending message %u (key 0x%x) to "
358		     "node %u\n", tmpret, DLM_UNLOCK_LOCK_MSG, dlm->key, owner);
359		if (dlm_is_host_down(tmpret)) {
360			/* NOTE: this seems strange, but it is what we want.
361			 * when the master goes down during a cancel or
362			 * unlock, the recovery code completes the operation
363			 * as if the master had not died, then passes the
364			 * updated state to the recovery master.  this thread
365			 * just needs to finish out the operation and call
366			 * the unlockast. */
367			ret = DLM_NORMAL;
368		} else {
369			/* something bad.  this will BUG in ocfs2 */
370			ret = dlm_err_to_dlm_status(tmpret);
371		}
372	}
373
374	return ret;
375}
376
377/*
378 * locking:
379 *   caller needs:  none
380 *   taken:         takes and drops res->spinlock
381 *   held on exit:  none
382 * returns: DLM_NORMAL, DLM_BADARGS, DLM_IVLOCKID,
383 *          return value from dlmunlock_master
384 */
385int dlm_unlock_lock_handler(struct o2net_msg *msg, u32 len, void *data,
386			    void **ret_data)
387{
388	struct dlm_ctxt *dlm = data;
389	struct dlm_unlock_lock *unlock = (struct dlm_unlock_lock *)msg->buf;
390	struct dlm_lock_resource *res = NULL;
391	struct list_head *iter;
392	struct dlm_lock *lock = NULL;
393	enum dlm_status status = DLM_NORMAL;
394	int found = 0, i;
395	struct dlm_lockstatus *lksb = NULL;
396	int ignore;
397	u32 flags;
398	struct list_head *queue;
399
400	flags = be32_to_cpu(unlock->flags);
401
402	if (flags & LKM_GET_LVB) {
403		mlog(ML_ERROR, "bad args!  GET_LVB specified on unlock!\n");
404		return DLM_BADARGS;
405	}
406
407	if ((flags & (LKM_PUT_LVB|LKM_CANCEL)) == (LKM_PUT_LVB|LKM_CANCEL)) {
408		mlog(ML_ERROR, "bad args!  cannot modify lvb on a CANCEL "
409		     "request!\n");
410		return DLM_BADARGS;
411	}
412
413	if (unlock->namelen > DLM_LOCKID_NAME_MAX) {
414		mlog(ML_ERROR, "Invalid name length in unlock handler!\n");
415		return DLM_IVBUFLEN;
416	}
417
418	if (!dlm_grab(dlm))
419		return DLM_REJECTED;
420
421	mlog_bug_on_msg(!dlm_domain_fully_joined(dlm),
422			"Domain %s not fully joined!\n", dlm->name);
423
424	mlog(0, "lvb: %s\n", flags & LKM_PUT_LVB ? "put lvb" : "none");
425
426	res = dlm_lookup_lockres(dlm, unlock->name, unlock->namelen);
427	if (!res) {
428		/* We assume here that a no lock resource simply means
429		 * it was migrated away and destroyed before the other
430		 * node could detect it. */
431		mlog(0, "returning DLM_FORWARD -- res no longer exists\n");
432		status = DLM_FORWARD;
433		goto not_found;
434	}
435
436	queue=&res->granted;
437	found = 0;
438	spin_lock(&res->spinlock);
439	if (res->state & DLM_LOCK_RES_RECOVERING) {
440		spin_unlock(&res->spinlock);
441		mlog(0, "returning DLM_RECOVERING\n");
442		status = DLM_RECOVERING;
443		goto leave;
444	}
445
446	if (res->state & DLM_LOCK_RES_MIGRATING) {
447		spin_unlock(&res->spinlock);
448		mlog(0, "returning DLM_MIGRATING\n");
449		status = DLM_MIGRATING;
450		goto leave;
451	}
452
453	if (res->owner != dlm->node_num) {
454		spin_unlock(&res->spinlock);
455		mlog(0, "returning DLM_FORWARD -- not master\n");
456		status = DLM_FORWARD;
457		goto leave;
458	}
459
460	for (i=0; i<3; i++) {
461		list_for_each(iter, queue) {
462			lock = list_entry(iter, struct dlm_lock, list);
463			if (lock->ml.cookie == unlock->cookie &&
464		    	    lock->ml.node == unlock->node_idx) {
465				dlm_lock_get(lock);
466				found = 1;
467				break;
468			}
469		}
470		if (found)
471			break;
472		/* scan granted -> converting -> blocked queues */
473		queue++;
474	}
475	spin_unlock(&res->spinlock);
476	if (!found) {
477		status = DLM_IVLOCKID;
478		goto not_found;
479	}
480
481	/* lock was found on queue */
482	lksb = lock->lksb;
483	if (flags & (LKM_VALBLK|LKM_PUT_LVB) &&
484	    lock->ml.type != LKM_EXMODE)
485		flags &= ~(LKM_VALBLK|LKM_PUT_LVB);
486
487	/* unlockast only called on originating node */
488	if (flags & LKM_PUT_LVB) {
489		lksb->flags |= DLM_LKSB_PUT_LVB;
490		memcpy(&lksb->lvb[0], &unlock->lvb[0], DLM_LVB_LEN);
491	}
492
493	/* if this is in-progress, propagate the DLM_FORWARD
494	 * all the way back out */
495	status = dlmunlock_master(dlm, res, lock, lksb, flags, &ignore);
496	if (status == DLM_FORWARD)
497		mlog(0, "lockres is in progress\n");
498
499	if (flags & LKM_PUT_LVB)
500		lksb->flags &= ~DLM_LKSB_PUT_LVB;
501
502	dlm_lockres_calc_usage(dlm, res);
503	dlm_kick_thread(dlm, res);
504
505not_found:
506	if (!found)
507		mlog(ML_ERROR, "failed to find lock to unlock! "
508			       "cookie=%u:%llu\n",
509		     dlm_get_lock_cookie_node(be64_to_cpu(unlock->cookie)),
510		     dlm_get_lock_cookie_seq(be64_to_cpu(unlock->cookie)));
511	else
512		dlm_lock_put(lock);
513
514leave:
515	if (res)
516		dlm_lockres_put(res);
517
518	dlm_put(dlm);
519
520	return status;
521}
522
523
524static enum dlm_status dlm_get_cancel_actions(struct dlm_ctxt *dlm,
525					      struct dlm_lock_resource *res,
526					      struct dlm_lock *lock,
527					      struct dlm_lockstatus *lksb,
528					      int *actions)
529{
530	enum dlm_status status;
531
532	if (dlm_lock_on_list(&res->blocked, lock)) {
533		/* cancel this outright */
534		status = DLM_NORMAL;
535		*actions = (DLM_UNLOCK_CALL_AST |
536			    DLM_UNLOCK_REMOVE_LOCK);
537	} else if (dlm_lock_on_list(&res->converting, lock)) {
538		/* cancel the request, put back on granted */
539		status = DLM_NORMAL;
540		*actions = (DLM_UNLOCK_CALL_AST |
541			    DLM_UNLOCK_REMOVE_LOCK |
542			    DLM_UNLOCK_REGRANT_LOCK |
543			    DLM_UNLOCK_CLEAR_CONVERT_TYPE);
544	} else if (dlm_lock_on_list(&res->granted, lock)) {
545		/* too late, already granted. */
546		status = DLM_CANCELGRANT;
547		*actions = DLM_UNLOCK_CALL_AST;
548	} else {
549		mlog(ML_ERROR, "lock to cancel is not on any list!\n");
550		status = DLM_IVLOCKID;
551		*actions = 0;
552	}
553	return status;
554}
555
556static enum dlm_status dlm_get_unlock_actions(struct dlm_ctxt *dlm,
557					      struct dlm_lock_resource *res,
558					      struct dlm_lock *lock,
559					      struct dlm_lockstatus *lksb,
560					      int *actions)
561{
562	enum dlm_status status;
563
564	/* unlock request */
565	if (!dlm_lock_on_list(&res->granted, lock)) {
566		status = DLM_DENIED;
567		dlm_error(status);
568		*actions = 0;
569	} else {
570		/* unlock granted lock */
571		status = DLM_NORMAL;
572		*actions = (DLM_UNLOCK_FREE_LOCK |
573			    DLM_UNLOCK_CALL_AST |
574			    DLM_UNLOCK_REMOVE_LOCK);
575	}
576	return status;
577}
578
579/* there seems to be no point in doing this async
580 * since (even for the remote case) there is really
581 * no work to queue up... so just do it and fire the
582 * unlockast by hand when done... */
583enum dlm_status dlmunlock(struct dlm_ctxt *dlm, struct dlm_lockstatus *lksb,
584			  int flags, dlm_astunlockfunc_t *unlockast, void *data)
585{
586	enum dlm_status status;
587	struct dlm_lock_resource *res;
588	struct dlm_lock *lock = NULL;
589	int call_ast, is_master;
590
591	mlog_entry_void();
592
593	if (!lksb) {
594		dlm_error(DLM_BADARGS);
595		return DLM_BADARGS;
596	}
597
598	if (flags & ~(LKM_CANCEL | LKM_VALBLK | LKM_INVVALBLK)) {
599		dlm_error(DLM_BADPARAM);
600		return DLM_BADPARAM;
601	}
602
603	if ((flags & (LKM_VALBLK | LKM_CANCEL)) == (LKM_VALBLK | LKM_CANCEL)) {
604		mlog(0, "VALBLK given with CANCEL: ignoring VALBLK\n");
605		flags &= ~LKM_VALBLK;
606	}
607
608	if (!lksb->lockid || !lksb->lockid->lockres) {
609		dlm_error(DLM_BADPARAM);
610		return DLM_BADPARAM;
611	}
612
613	lock = lksb->lockid;
614	BUG_ON(!lock);
615	dlm_lock_get(lock);
616
617	res = lock->lockres;
618	BUG_ON(!res);
619	dlm_lockres_get(res);
620retry:
621	call_ast = 0;
622	/* need to retry up here because owner may have changed */
623	mlog(0, "lock=%p res=%p\n", lock, res);
624
625	spin_lock(&res->spinlock);
626	is_master = (res->owner == dlm->node_num);
627	if (flags & LKM_VALBLK && lock->ml.type != LKM_EXMODE)
628		flags &= ~LKM_VALBLK;
629	spin_unlock(&res->spinlock);
630
631	if (is_master) {
632		status = dlmunlock_master(dlm, res, lock, lksb, flags,
633					  &call_ast);
634		mlog(0, "done calling dlmunlock_master: returned %d, "
635		     "call_ast is %d\n", status, call_ast);
636	} else {
637		status = dlmunlock_remote(dlm, res, lock, lksb, flags,
638					  &call_ast);
639		mlog(0, "done calling dlmunlock_remote: returned %d, "
640		     "call_ast is %d\n", status, call_ast);
641	}
642
643	if (status == DLM_RECOVERING ||
644	    status == DLM_MIGRATING ||
645	    status == DLM_FORWARD) {
646		/* We want to go away for a tiny bit to allow recovery
647		 * / migration to complete on this resource. I don't
648		 * know of any wait queue we could sleep on as this
649		 * may be happening on another node. Perhaps the
650		 * proper solution is to queue up requests on the
651		 * other end? */
652
653		/* do we want to yield(); ?? */
654		msleep(50);
655
656		mlog(0, "retrying unlock due to pending recovery/"
657		     "migration/in-progress\n");
658		goto retry;
659	}
660
661	if (call_ast) {
662		mlog(0, "calling unlockast(%p, %d)\n", data, status);
663		if (is_master) {
664			/* it is possible that there is one last bast
665			 * pending.  make sure it is flushed, then
666			 * call the unlockast.
667			 * not an issue if this is a mastered remotely,
668			 * since this lock has been removed from the
669			 * lockres queues and cannot be found. */
670			dlm_kick_thread(dlm, NULL);
671			wait_event(dlm->ast_wq,
672				   dlm_lock_basts_flushed(dlm, lock));
673		}
674		(*unlockast)(data, status);
675	}
676
677	if (status == DLM_CANCELGRANT)
678		status = DLM_NORMAL;
679
680	if (status == DLM_NORMAL) {
681		mlog(0, "kicking the thread\n");
682		dlm_kick_thread(dlm, res);
683	} else
684		dlm_error(status);
685
686	dlm_lockres_calc_usage(dlm, res);
687	dlm_lockres_put(res);
688	dlm_lock_put(lock);
689
690	mlog(0, "returning status=%d!\n", status);
691	return status;
692}
693EXPORT_SYMBOL_GPL(dlmunlock);
694