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			   status == DLM_NOLOCKMGR
196			   ) {
197			/* must clear the actions because this unlock
198			 * is about to be retried.  cannot free or do
199			 * any list manipulation. */
200			mlog(0, "%s:%.*s: clearing actions, %s\n",
201			     dlm->name, res->lockname.len,
202			     res->lockname.name,
203			     status==DLM_RECOVERING?"recovering":
204			     (status==DLM_MIGRATING?"migrating":
205				(status == DLM_FORWARD ? "forward" :
206						"nolockmanager")));
207			actions = 0;
208		}
209		if (flags & LKM_CANCEL)
210			lock->cancel_pending = 0;
211		else
212			lock->unlock_pending = 0;
213
214	}
215
216	/* get an extra ref on lock.  if we are just switching
217	 * lists here, we dont want the lock to go away. */
218	dlm_lock_get(lock);
219
220	if (actions & DLM_UNLOCK_REMOVE_LOCK) {
221		list_del_init(&lock->list);
222		dlm_lock_put(lock);
223	}
224	if (actions & DLM_UNLOCK_REGRANT_LOCK) {
225		dlm_lock_get(lock);
226		list_add_tail(&lock->list, &res->granted);
227	}
228	if (actions & DLM_UNLOCK_CLEAR_CONVERT_TYPE) {
229		mlog(0, "clearing convert_type at %smaster node\n",
230		     master_node ? "" : "non-");
231		lock->ml.convert_type = LKM_IVMODE;
232	}
233
234	/* remove the extra ref on lock */
235	dlm_lock_put(lock);
236
237leave:
238	res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
239	if (!dlm_lock_on_list(&res->converting, lock))
240		BUG_ON(lock->ml.convert_type != LKM_IVMODE);
241	else
242		BUG_ON(lock->ml.convert_type == LKM_IVMODE);
243	spin_unlock(&lock->spinlock);
244	spin_unlock(&res->spinlock);
245	wake_up(&res->wq);
246
247	/* let the caller's final dlm_lock_put handle the actual kfree */
248	if (actions & DLM_UNLOCK_FREE_LOCK) {
249		/* this should always be coupled with list removal */
250		BUG_ON(!(actions & DLM_UNLOCK_REMOVE_LOCK));
251		mlog(0, "lock %u:%llu should be gone now! refs=%d\n",
252		     dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
253		     dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
254		     atomic_read(&lock->lock_refs.refcount)-1);
255		dlm_lock_put(lock);
256	}
257	if (actions & DLM_UNLOCK_CALL_AST)
258		*call_ast = 1;
259
260	/* if cancel or unlock succeeded, lvb work is done */
261	if (status == DLM_NORMAL)
262		lksb->flags &= ~(DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB);
263
264	return status;
265}
266
267void dlm_commit_pending_unlock(struct dlm_lock_resource *res,
268			       struct dlm_lock *lock)
269{
270	/* leave DLM_LKSB_PUT_LVB on the lksb so any final
271	 * update of the lvb will be sent to the new master */
272	list_del_init(&lock->list);
273}
274
275void dlm_commit_pending_cancel(struct dlm_lock_resource *res,
276			       struct dlm_lock *lock)
277{
278	list_move_tail(&lock->list, &res->granted);
279	lock->ml.convert_type = LKM_IVMODE;
280}
281
282
283static inline enum dlm_status dlmunlock_master(struct dlm_ctxt *dlm,
284					  struct dlm_lock_resource *res,
285					  struct dlm_lock *lock,
286					  struct dlm_lockstatus *lksb,
287					  int flags,
288					  int *call_ast)
289{
290	return dlmunlock_common(dlm, res, lock, lksb, flags, call_ast, 1);
291}
292
293static inline enum dlm_status dlmunlock_remote(struct dlm_ctxt *dlm,
294					  struct dlm_lock_resource *res,
295					  struct dlm_lock *lock,
296					  struct dlm_lockstatus *lksb,
297					  int flags, int *call_ast)
298{
299	return dlmunlock_common(dlm, res, lock, lksb, flags, call_ast, 0);
300}
301
302/*
303 * locking:
304 *   caller needs:  none
305 *   taken:         none
306 *   held on exit:  none
307 * returns: DLM_NORMAL, DLM_NOLOCKMGR, status from network
308 */
309static enum dlm_status dlm_send_remote_unlock_request(struct dlm_ctxt *dlm,
310						 struct dlm_lock_resource *res,
311						 struct dlm_lock *lock,
312						 struct dlm_lockstatus *lksb,
313						 int flags,
314						 u8 owner)
315{
316	struct dlm_unlock_lock unlock;
317	int tmpret;
318	enum dlm_status ret;
319	int status = 0;
320	struct kvec vec[2];
321	size_t veclen = 1;
322
323	mlog(0, "%.*s\n", res->lockname.len, res->lockname.name);
324
325	if (owner == dlm->node_num) {
326		/* ended up trying to contact ourself.  this means
327		 * that the lockres had been remote but became local
328		 * via a migration.  just retry it, now as local */
329		mlog(0, "%s:%.*s: this node became the master due to a "
330		     "migration, re-evaluate now\n", dlm->name,
331		     res->lockname.len, res->lockname.name);
332		return DLM_FORWARD;
333	}
334
335	memset(&unlock, 0, sizeof(unlock));
336	unlock.node_idx = dlm->node_num;
337	unlock.flags = cpu_to_be32(flags);
338	unlock.cookie = lock->ml.cookie;
339	unlock.namelen = res->lockname.len;
340	memcpy(unlock.name, res->lockname.name, unlock.namelen);
341
342	vec[0].iov_len = sizeof(struct dlm_unlock_lock);
343	vec[0].iov_base = &unlock;
344
345	if (flags & LKM_PUT_LVB) {
346		/* extra data to send if we are updating lvb */
347		vec[1].iov_len = DLM_LVB_LEN;
348		vec[1].iov_base = lock->lksb->lvb;
349		veclen++;
350	}
351
352	tmpret = o2net_send_message_vec(DLM_UNLOCK_LOCK_MSG, dlm->key,
353					vec, veclen, owner, &status);
354	if (tmpret >= 0) {
355		// successfully sent and received
356		if (status == DLM_FORWARD)
357			mlog(0, "master was in-progress.  retry\n");
358		ret = status;
359	} else {
360		mlog(ML_ERROR, "Error %d when sending message %u (key 0x%x) to "
361		     "node %u\n", tmpret, DLM_UNLOCK_LOCK_MSG, dlm->key, owner);
362		if (dlm_is_host_down(tmpret)) {
363			/* NOTE: this seems strange, but it is what we want.
364			 * when the master goes down during a cancel or
365			 * unlock, the recovery code completes the operation
366			 * as if the master had not died, then passes the
367			 * updated state to the recovery master.  this thread
368			 * just needs to finish out the operation and call
369			 * the unlockast. */
370			if (dlm_is_node_dead(dlm, owner))
371				ret = DLM_NORMAL;
372			else
373				ret = DLM_NOLOCKMGR;
374		} else {
375			/* something bad.  this will BUG in ocfs2 */
376			ret = dlm_err_to_dlm_status(tmpret);
377		}
378	}
379
380	return ret;
381}
382
383/*
384 * locking:
385 *   caller needs:  none
386 *   taken:         takes and drops res->spinlock
387 *   held on exit:  none
388 * returns: DLM_NORMAL, DLM_BADARGS, DLM_IVLOCKID,
389 *          return value from dlmunlock_master
390 */
391int dlm_unlock_lock_handler(struct o2net_msg *msg, u32 len, void *data,
392			    void **ret_data)
393{
394	struct dlm_ctxt *dlm = data;
395	struct dlm_unlock_lock *unlock = (struct dlm_unlock_lock *)msg->buf;
396	struct dlm_lock_resource *res = NULL;
397	struct dlm_lock *lock = NULL;
398	enum dlm_status status = DLM_NORMAL;
399	int found = 0, i;
400	struct dlm_lockstatus *lksb = NULL;
401	int ignore;
402	u32 flags;
403	struct list_head *queue;
404
405	flags = be32_to_cpu(unlock->flags);
406
407	if (flags & LKM_GET_LVB) {
408		mlog(ML_ERROR, "bad args!  GET_LVB specified on unlock!\n");
409		return DLM_BADARGS;
410	}
411
412	if ((flags & (LKM_PUT_LVB|LKM_CANCEL)) == (LKM_PUT_LVB|LKM_CANCEL)) {
413		mlog(ML_ERROR, "bad args!  cannot modify lvb on a CANCEL "
414		     "request!\n");
415		return DLM_BADARGS;
416	}
417
418	if (unlock->namelen > DLM_LOCKID_NAME_MAX) {
419		mlog(ML_ERROR, "Invalid name length in unlock handler!\n");
420		return DLM_IVBUFLEN;
421	}
422
423	if (!dlm_grab(dlm))
424		return DLM_REJECTED;
425
426	mlog_bug_on_msg(!dlm_domain_fully_joined(dlm),
427			"Domain %s not fully joined!\n", dlm->name);
428
429	mlog(0, "lvb: %s\n", flags & LKM_PUT_LVB ? "put lvb" : "none");
430
431	res = dlm_lookup_lockres(dlm, unlock->name, unlock->namelen);
432	if (!res) {
433		/* We assume here that a no lock resource simply means
434		 * it was migrated away and destroyed before the other
435		 * node could detect it. */
436		mlog(0, "returning DLM_FORWARD -- res no longer exists\n");
437		status = DLM_FORWARD;
438		goto not_found;
439	}
440
441	queue=&res->granted;
442	found = 0;
443	spin_lock(&res->spinlock);
444	if (res->state & DLM_LOCK_RES_RECOVERING) {
445		spin_unlock(&res->spinlock);
446		mlog(0, "returning DLM_RECOVERING\n");
447		status = DLM_RECOVERING;
448		goto leave;
449	}
450
451	if (res->state & DLM_LOCK_RES_MIGRATING) {
452		spin_unlock(&res->spinlock);
453		mlog(0, "returning DLM_MIGRATING\n");
454		status = DLM_MIGRATING;
455		goto leave;
456	}
457
458	if (res->owner != dlm->node_num) {
459		spin_unlock(&res->spinlock);
460		mlog(0, "returning DLM_FORWARD -- not master\n");
461		status = DLM_FORWARD;
462		goto leave;
463	}
464
465	for (i=0; i<3; i++) {
466		list_for_each_entry(lock, queue, list) {
467			if (lock->ml.cookie == unlock->cookie &&
468		    	    lock->ml.node == unlock->node_idx) {
469				dlm_lock_get(lock);
470				found = 1;
471				break;
472			}
473		}
474		if (found)
475			break;
476		/* scan granted -> converting -> blocked queues */
477		queue++;
478	}
479	spin_unlock(&res->spinlock);
480	if (!found) {
481		status = DLM_IVLOCKID;
482		goto not_found;
483	}
484
485	/* lock was found on queue */
486	lksb = lock->lksb;
487	if (flags & (LKM_VALBLK|LKM_PUT_LVB) &&
488	    lock->ml.type != LKM_EXMODE)
489		flags &= ~(LKM_VALBLK|LKM_PUT_LVB);
490
491	/* unlockast only called on originating node */
492	if (flags & LKM_PUT_LVB) {
493		lksb->flags |= DLM_LKSB_PUT_LVB;
494		memcpy(&lksb->lvb[0], &unlock->lvb[0], DLM_LVB_LEN);
495	}
496
497	/* if this is in-progress, propagate the DLM_FORWARD
498	 * all the way back out */
499	status = dlmunlock_master(dlm, res, lock, lksb, flags, &ignore);
500	if (status == DLM_FORWARD)
501		mlog(0, "lockres is in progress\n");
502
503	if (flags & LKM_PUT_LVB)
504		lksb->flags &= ~DLM_LKSB_PUT_LVB;
505
506	dlm_lockres_calc_usage(dlm, res);
507	dlm_kick_thread(dlm, res);
508
509not_found:
510	if (!found)
511		mlog(ML_ERROR, "failed to find lock to unlock! "
512			       "cookie=%u:%llu\n",
513		     dlm_get_lock_cookie_node(be64_to_cpu(unlock->cookie)),
514		     dlm_get_lock_cookie_seq(be64_to_cpu(unlock->cookie)));
515	else
516		dlm_lock_put(lock);
517
518leave:
519	if (res)
520		dlm_lockres_put(res);
521
522	dlm_put(dlm);
523
524	return status;
525}
526
527
528static enum dlm_status dlm_get_cancel_actions(struct dlm_ctxt *dlm,
529					      struct dlm_lock_resource *res,
530					      struct dlm_lock *lock,
531					      struct dlm_lockstatus *lksb,
532					      int *actions)
533{
534	enum dlm_status status;
535
536	if (dlm_lock_on_list(&res->blocked, lock)) {
537		/* cancel this outright */
538		status = DLM_NORMAL;
539		*actions = (DLM_UNLOCK_CALL_AST |
540			    DLM_UNLOCK_REMOVE_LOCK);
541	} else if (dlm_lock_on_list(&res->converting, lock)) {
542		/* cancel the request, put back on granted */
543		status = DLM_NORMAL;
544		*actions = (DLM_UNLOCK_CALL_AST |
545			    DLM_UNLOCK_REMOVE_LOCK |
546			    DLM_UNLOCK_REGRANT_LOCK |
547			    DLM_UNLOCK_CLEAR_CONVERT_TYPE);
548	} else if (dlm_lock_on_list(&res->granted, lock)) {
549		/* too late, already granted. */
550		status = DLM_CANCELGRANT;
551		*actions = DLM_UNLOCK_CALL_AST;
552	} else {
553		mlog(ML_ERROR, "lock to cancel is not on any list!\n");
554		status = DLM_IVLOCKID;
555		*actions = 0;
556	}
557	return status;
558}
559
560static enum dlm_status dlm_get_unlock_actions(struct dlm_ctxt *dlm,
561					      struct dlm_lock_resource *res,
562					      struct dlm_lock *lock,
563					      struct dlm_lockstatus *lksb,
564					      int *actions)
565{
566	enum dlm_status status;
567
568	/* unlock request */
569	if (!dlm_lock_on_list(&res->granted, lock)) {
570		status = DLM_DENIED;
571		dlm_error(status);
572		*actions = 0;
573	} else {
574		/* unlock granted lock */
575		status = DLM_NORMAL;
576		*actions = (DLM_UNLOCK_FREE_LOCK |
577			    DLM_UNLOCK_CALL_AST |
578			    DLM_UNLOCK_REMOVE_LOCK);
579	}
580	return status;
581}
582
583/* there seems to be no point in doing this async
584 * since (even for the remote case) there is really
585 * no work to queue up... so just do it and fire the
586 * unlockast by hand when done... */
587enum dlm_status dlmunlock(struct dlm_ctxt *dlm, struct dlm_lockstatus *lksb,
588			  int flags, dlm_astunlockfunc_t *unlockast, void *data)
589{
590	enum dlm_status status;
591	struct dlm_lock_resource *res;
592	struct dlm_lock *lock = NULL;
593	int call_ast, is_master;
594
595	if (!lksb) {
596		dlm_error(DLM_BADARGS);
597		return DLM_BADARGS;
598	}
599
600	if (flags & ~(LKM_CANCEL | LKM_VALBLK | LKM_INVVALBLK)) {
601		dlm_error(DLM_BADPARAM);
602		return DLM_BADPARAM;
603	}
604
605	if ((flags & (LKM_VALBLK | LKM_CANCEL)) == (LKM_VALBLK | LKM_CANCEL)) {
606		mlog(0, "VALBLK given with CANCEL: ignoring VALBLK\n");
607		flags &= ~LKM_VALBLK;
608	}
609
610	if (!lksb->lockid || !lksb->lockid->lockres) {
611		dlm_error(DLM_BADPARAM);
612		return DLM_BADPARAM;
613	}
614
615	lock = lksb->lockid;
616	BUG_ON(!lock);
617	dlm_lock_get(lock);
618
619	res = lock->lockres;
620	BUG_ON(!res);
621	dlm_lockres_get(res);
622retry:
623	call_ast = 0;
624	/* need to retry up here because owner may have changed */
625	mlog(0, "lock=%p res=%p\n", lock, res);
626
627	spin_lock(&res->spinlock);
628	is_master = (res->owner == dlm->node_num);
629	if (flags & LKM_VALBLK && lock->ml.type != LKM_EXMODE)
630		flags &= ~LKM_VALBLK;
631	spin_unlock(&res->spinlock);
632
633	if (is_master) {
634		status = dlmunlock_master(dlm, res, lock, lksb, flags,
635					  &call_ast);
636		mlog(0, "done calling dlmunlock_master: returned %d, "
637		     "call_ast is %d\n", status, call_ast);
638	} else {
639		status = dlmunlock_remote(dlm, res, lock, lksb, flags,
640					  &call_ast);
641		mlog(0, "done calling dlmunlock_remote: returned %d, "
642		     "call_ast is %d\n", status, call_ast);
643	}
644
645	if (status == DLM_RECOVERING ||
646	    status == DLM_MIGRATING ||
647	    status == DLM_FORWARD ||
648	    status == DLM_NOLOCKMGR) {
649
650		/* We want to go away for a tiny bit to allow recovery
651		 * / migration to complete on this resource. I don't
652		 * know of any wait queue we could sleep on as this
653		 * may be happening on another node. Perhaps the
654		 * proper solution is to queue up requests on the
655		 * other end? */
656
657		/* do we want to yield(); ?? */
658		msleep(50);
659
660		mlog(0, "retrying unlock due to pending recovery/"
661		     "migration/in-progress/reconnect\n");
662		goto retry;
663	}
664
665	if (call_ast) {
666		mlog(0, "calling unlockast(%p, %d)\n", data, status);
667		if (is_master) {
668			/* it is possible that there is one last bast
669			 * pending.  make sure it is flushed, then
670			 * call the unlockast.
671			 * not an issue if this is a mastered remotely,
672			 * since this lock has been removed from the
673			 * lockres queues and cannot be found. */
674			dlm_kick_thread(dlm, NULL);
675			wait_event(dlm->ast_wq,
676				   dlm_lock_basts_flushed(dlm, lock));
677		}
678		(*unlockast)(data, status);
679	}
680
681	if (status == DLM_CANCELGRANT)
682		status = DLM_NORMAL;
683
684	if (status == DLM_NORMAL) {
685		mlog(0, "kicking the thread\n");
686		dlm_kick_thread(dlm, res);
687	} else
688		dlm_error(status);
689
690	dlm_lockres_calc_usage(dlm, res);
691	dlm_lockres_put(res);
692	dlm_lock_put(lock);
693
694	mlog(0, "returning status=%d!\n", status);
695	return status;
696}
697EXPORT_SYMBOL_GPL(dlmunlock);
698
699