[PATCH] fs: use list_move()
[linux-2.6.git] / fs / ocfs2 / dlm / dlmunlock.c
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_move_tail(&lock->list, &res->granted);
275         lock->ml.convert_type = LKM_IVMODE;
276 }
277
278
279 static inline enum dlm_status dlmunlock_master(struct dlm_ctxt *dlm,
280                                           struct dlm_lock_resource *res,
281                                           struct dlm_lock *lock,
282                                           struct dlm_lockstatus *lksb,
283                                           int flags,
284                                           int *call_ast)
285 {
286         return dlmunlock_common(dlm, res, lock, lksb, flags, call_ast, 1);
287 }
288
289 static inline enum dlm_status dlmunlock_remote(struct dlm_ctxt *dlm,
290                                           struct dlm_lock_resource *res,
291                                           struct dlm_lock *lock,
292                                           struct dlm_lockstatus *lksb,
293                                           int flags, int *call_ast)
294 {
295         return dlmunlock_common(dlm, res, lock, lksb, flags, call_ast, 0);
296 }
297
298 /*
299  * locking:
300  *   caller needs:  none
301  *   taken:         none
302  *   held on exit:  none
303  * returns: DLM_NORMAL, DLM_NOLOCKMGR, status from network
304  */
305 static enum dlm_status dlm_send_remote_unlock_request(struct dlm_ctxt *dlm,
306                                                  struct dlm_lock_resource *res,
307                                                  struct dlm_lock *lock,
308                                                  struct dlm_lockstatus *lksb,
309                                                  int flags,
310                                                  u8 owner)
311 {
312         struct dlm_unlock_lock unlock;
313         int tmpret;
314         enum dlm_status ret;
315         int status = 0;
316         struct kvec vec[2];
317         size_t veclen = 1;
318
319         mlog_entry("%.*s\n", res->lockname.len, res->lockname.name);
320
321         memset(&unlock, 0, sizeof(unlock));
322         unlock.node_idx = dlm->node_num;
323         unlock.flags = cpu_to_be32(flags);
324         unlock.cookie = lock->ml.cookie;
325         unlock.namelen = res->lockname.len;
326         memcpy(unlock.name, res->lockname.name, unlock.namelen);
327
328         vec[0].iov_len = sizeof(struct dlm_unlock_lock);
329         vec[0].iov_base = &unlock;
330
331         if (flags & LKM_PUT_LVB) {
332                 /* extra data to send if we are updating lvb */
333                 vec[1].iov_len = DLM_LVB_LEN;
334                 vec[1].iov_base = lock->lksb->lvb;
335                 veclen++;
336         }
337
338         tmpret = o2net_send_message_vec(DLM_UNLOCK_LOCK_MSG, dlm->key,
339                                         vec, veclen, owner, &status);
340         if (tmpret >= 0) {
341                 // successfully sent and received
342                 if (status == DLM_CANCELGRANT)
343                         ret = DLM_NORMAL;
344                 else if (status == DLM_FORWARD) {
345                         mlog(0, "master was in-progress.  retry\n");
346                         ret = DLM_FORWARD;
347                 } else
348                         ret = status;
349                 lksb->status = status;
350         } else {
351                 mlog_errno(tmpret);
352                 if (dlm_is_host_down(tmpret)) {
353                         /* NOTE: this seems strange, but it is what we want.
354                          * when the master goes down during a cancel or
355                          * unlock, the recovery code completes the operation
356                          * as if the master had not died, then passes the
357                          * updated state to the recovery master.  this thread
358                          * just needs to finish out the operation and call
359                          * the unlockast. */
360                         ret = DLM_NORMAL;
361                 } else {
362                         /* something bad.  this will BUG in ocfs2 */
363                         ret = dlm_err_to_dlm_status(tmpret);
364                 }
365                 lksb->status = ret;
366         }
367
368         return ret;
369 }
370
371 /*
372  * locking:
373  *   caller needs:  none
374  *   taken:         takes and drops res->spinlock
375  *   held on exit:  none
376  * returns: DLM_NORMAL, DLM_BADARGS, DLM_IVLOCKID,
377  *          return value from dlmunlock_master
378  */
379 int dlm_unlock_lock_handler(struct o2net_msg *msg, u32 len, void *data)
380 {
381         struct dlm_ctxt *dlm = data;
382         struct dlm_unlock_lock *unlock = (struct dlm_unlock_lock *)msg->buf;
383         struct dlm_lock_resource *res = NULL;
384         struct list_head *iter;
385         struct dlm_lock *lock = NULL;
386         enum dlm_status status = DLM_NORMAL;
387         int found = 0, i;
388         struct dlm_lockstatus *lksb = NULL;
389         int ignore;
390         u32 flags;
391         struct list_head *queue;
392
393         flags = be32_to_cpu(unlock->flags);
394
395         if (flags & LKM_GET_LVB) {
396                 mlog(ML_ERROR, "bad args!  GET_LVB specified on unlock!\n");
397                 return DLM_BADARGS;
398         }
399
400         if ((flags & (LKM_PUT_LVB|LKM_CANCEL)) == (LKM_PUT_LVB|LKM_CANCEL)) {
401                 mlog(ML_ERROR, "bad args!  cannot modify lvb on a CANCEL "
402                      "request!\n");
403                 return DLM_BADARGS;
404         }
405
406         if (unlock->namelen > DLM_LOCKID_NAME_MAX) {
407                 mlog(ML_ERROR, "Invalid name length in unlock handler!\n");
408                 return DLM_IVBUFLEN;
409         }
410
411         if (!dlm_grab(dlm))
412                 return DLM_REJECTED;
413
414         mlog_bug_on_msg(!dlm_domain_fully_joined(dlm),
415                         "Domain %s not fully joined!\n", dlm->name);
416
417         mlog(0, "lvb: %s\n", flags & LKM_PUT_LVB ? "put lvb" : "none");
418
419         res = dlm_lookup_lockres(dlm, unlock->name, unlock->namelen);
420         if (!res) {
421                 /* We assume here that a no lock resource simply means
422                  * it was migrated away and destroyed before the other
423                  * node could detect it. */
424                 mlog(0, "returning DLM_FORWARD -- res no longer exists\n");
425                 status = DLM_FORWARD;
426                 goto not_found;
427         }
428
429         queue=&res->granted;
430         found = 0;
431         spin_lock(&res->spinlock);
432         if (res->state & DLM_LOCK_RES_RECOVERING) {
433                 spin_unlock(&res->spinlock);
434                 mlog(0, "returning DLM_RECOVERING\n");
435                 status = DLM_RECOVERING;
436                 goto leave;
437         }
438
439         if (res->state & DLM_LOCK_RES_MIGRATING) {
440                 spin_unlock(&res->spinlock);
441                 mlog(0, "returning DLM_MIGRATING\n");
442                 status = DLM_MIGRATING;
443                 goto leave;
444         }
445
446         if (res->owner != dlm->node_num) {
447                 spin_unlock(&res->spinlock);
448                 mlog(0, "returning DLM_FORWARD -- not master\n");
449                 status = DLM_FORWARD;
450                 goto leave;
451         }
452
453         for (i=0; i<3; i++) {
454                 list_for_each(iter, queue) {
455                         lock = list_entry(iter, struct dlm_lock, list);
456                         if (lock->ml.cookie == unlock->cookie &&
457                             lock->ml.node == unlock->node_idx) {
458                                 dlm_lock_get(lock);
459                                 found = 1;
460                                 break;
461                         }
462                 }
463                 if (found)
464                         break;
465                 /* scan granted -> converting -> blocked queues */
466                 queue++;
467         }
468         spin_unlock(&res->spinlock);
469         if (!found) {
470                 status = DLM_IVLOCKID;
471                 goto not_found;
472         }
473
474         /* lock was found on queue */
475         lksb = lock->lksb;
476         /* unlockast only called on originating node */
477         if (flags & LKM_PUT_LVB) {
478                 lksb->flags |= DLM_LKSB_PUT_LVB;
479                 memcpy(&lksb->lvb[0], &unlock->lvb[0], DLM_LVB_LEN);
480         }
481
482         /* if this is in-progress, propagate the DLM_FORWARD
483          * all the way back out */
484         status = dlmunlock_master(dlm, res, lock, lksb, flags, &ignore);
485         if (status == DLM_FORWARD)
486                 mlog(0, "lockres is in progress\n");
487
488         if (flags & LKM_PUT_LVB)
489                 lksb->flags &= ~DLM_LKSB_PUT_LVB;
490
491         dlm_lockres_calc_usage(dlm, res);
492         dlm_kick_thread(dlm, res);
493
494 not_found:
495         if (!found)
496                 mlog(ML_ERROR, "failed to find lock to unlock! "
497                                "cookie=%u:%llu\n",
498                                dlm_get_lock_cookie_node(unlock->cookie),
499                                dlm_get_lock_cookie_seq(unlock->cookie));
500         else {
501                 /* send the lksb->status back to the other node */
502                 status = lksb->status;
503                 dlm_lock_put(lock);
504         }
505
506 leave:
507         if (res)
508                 dlm_lockres_put(res);
509
510         dlm_put(dlm);
511
512         return status;
513 }
514
515
516 static enum dlm_status dlm_get_cancel_actions(struct dlm_ctxt *dlm,
517                                               struct dlm_lock_resource *res,
518                                               struct dlm_lock *lock,
519                                               struct dlm_lockstatus *lksb,
520                                               int *actions)
521 {
522         enum dlm_status status;
523
524         if (dlm_lock_on_list(&res->blocked, lock)) {
525                 /* cancel this outright */
526                 lksb->status = DLM_NORMAL;
527                 status = DLM_NORMAL;
528                 *actions = (DLM_UNLOCK_CALL_AST |
529                             DLM_UNLOCK_REMOVE_LOCK);
530         } else if (dlm_lock_on_list(&res->converting, lock)) {
531                 /* cancel the request, put back on granted */
532                 lksb->status = DLM_NORMAL;
533                 status = DLM_NORMAL;
534                 *actions = (DLM_UNLOCK_CALL_AST |
535                             DLM_UNLOCK_REMOVE_LOCK |
536                             DLM_UNLOCK_REGRANT_LOCK |
537                             DLM_UNLOCK_CLEAR_CONVERT_TYPE);
538         } else if (dlm_lock_on_list(&res->granted, lock)) {
539                 /* too late, already granted.  DLM_CANCELGRANT */
540                 lksb->status = DLM_CANCELGRANT;
541                 status = DLM_NORMAL;
542                 *actions = DLM_UNLOCK_CALL_AST;
543         } else {
544                 mlog(ML_ERROR, "lock to cancel is not on any list!\n");
545                 lksb->status = DLM_IVLOCKID;
546                 status = DLM_IVLOCKID;
547                 *actions = 0;
548         }
549         return status;
550 }
551
552 static enum dlm_status dlm_get_unlock_actions(struct dlm_ctxt *dlm,
553                                               struct dlm_lock_resource *res,
554                                               struct dlm_lock *lock,
555                                               struct dlm_lockstatus *lksb,
556                                               int *actions)
557 {
558         enum dlm_status status;
559
560         /* unlock request */
561         if (!dlm_lock_on_list(&res->granted, lock)) {
562                 lksb->status = DLM_DENIED;
563                 status = DLM_DENIED;
564                 dlm_error(status);
565                 *actions = 0;
566         } else {
567                 /* unlock granted lock */
568                 lksb->status = DLM_NORMAL;
569                 status = DLM_NORMAL;
570                 *actions = (DLM_UNLOCK_FREE_LOCK |
571                             DLM_UNLOCK_CALL_AST |
572                             DLM_UNLOCK_REMOVE_LOCK);
573         }
574         return status;
575 }
576
577 /* there seems to be no point in doing this async
578  * since (even for the remote case) there is really
579  * no work to queue up... so just do it and fire the
580  * unlockast by hand when done... */
581 enum dlm_status dlmunlock(struct dlm_ctxt *dlm, struct dlm_lockstatus *lksb,
582                           int flags, dlm_astunlockfunc_t *unlockast, void *data)
583 {
584         enum dlm_status status;
585         struct dlm_lock_resource *res;
586         struct dlm_lock *lock = NULL;
587         int call_ast, is_master;
588
589         mlog_entry_void();
590
591         if (!lksb) {
592                 dlm_error(DLM_BADARGS);
593                 return DLM_BADARGS;
594         }
595
596         if (flags & ~(LKM_CANCEL | LKM_VALBLK | LKM_INVVALBLK)) {
597                 dlm_error(DLM_BADPARAM);
598                 return DLM_BADPARAM;
599         }
600
601         if ((flags & (LKM_VALBLK | LKM_CANCEL)) == (LKM_VALBLK | LKM_CANCEL)) {
602                 mlog(0, "VALBLK given with CANCEL: ignoring VALBLK\n");
603                 flags &= ~LKM_VALBLK;
604         }
605
606         if (!lksb->lockid || !lksb->lockid->lockres) {
607                 dlm_error(DLM_BADPARAM);
608                 return DLM_BADPARAM;
609         }
610
611         lock = lksb->lockid;
612         BUG_ON(!lock);
613         dlm_lock_get(lock);
614
615         res = lock->lockres;
616         BUG_ON(!res);
617         dlm_lockres_get(res);
618 retry:
619         call_ast = 0;
620         /* need to retry up here because owner may have changed */
621         mlog(0, "lock=%p res=%p\n", lock, res);
622
623         spin_lock(&res->spinlock);
624         is_master = (res->owner == dlm->node_num);
625         spin_unlock(&res->spinlock);
626
627         if (is_master) {
628                 status = dlmunlock_master(dlm, res, lock, lksb, flags,
629                                           &call_ast);
630                 mlog(0, "done calling dlmunlock_master: returned %d, "
631                      "call_ast is %d\n", status, call_ast);
632         } else {
633                 status = dlmunlock_remote(dlm, res, lock, lksb, flags,
634                                           &call_ast);
635                 mlog(0, "done calling dlmunlock_remote: returned %d, "
636                      "call_ast is %d\n", status, call_ast);
637         }
638
639         if (status == DLM_RECOVERING ||
640             status == DLM_MIGRATING ||
641             status == DLM_FORWARD) {
642                 /* We want to go away for a tiny bit to allow recovery
643                  * / migration to complete on this resource. I don't
644                  * know of any wait queue we could sleep on as this
645                  * may be happening on another node. Perhaps the
646                  * proper solution is to queue up requests on the
647                  * other end? */
648
649                 /* do we want to yield(); ?? */
650                 msleep(50);
651
652                 mlog(0, "retrying unlock due to pending recovery/"
653                      "migration/in-progress\n");
654                 goto retry;
655         }
656
657         if (call_ast) {
658                 mlog(0, "calling unlockast(%p, %d)\n", data, lksb->status);
659                 if (is_master) {
660                         /* it is possible that there is one last bast 
661                          * pending.  make sure it is flushed, then
662                          * call the unlockast.
663                          * not an issue if this is a mastered remotely,
664                          * since this lock has been removed from the
665                          * lockres queues and cannot be found. */
666                         dlm_kick_thread(dlm, NULL);
667                         wait_event(dlm->ast_wq, 
668                                    dlm_lock_basts_flushed(dlm, lock));
669                 }
670                 (*unlockast)(data, lksb->status);
671         }
672
673         if (status == DLM_NORMAL) {
674                 mlog(0, "kicking the thread\n");
675                 dlm_kick_thread(dlm, res);
676         } else
677                 dlm_error(status);
678
679         dlm_lockres_calc_usage(dlm, res);
680         dlm_lockres_put(res);
681         dlm_lock_put(lock);
682
683         mlog(0, "returning status=%d!\n", status);
684         return status;
685 }
686 EXPORT_SYMBOL_GPL(dlmunlock);
687