Merge branch 'for-linus' of ssh://master.kernel.org/pub/scm/linux/kernel/git/ieee1394...
[linux-2.6] / 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         if (res->state & DLM_LOCK_RES_MIGRATING) {
151                 status = DLM_MIGRATING;
152                 goto leave;
153         }
154
155         /* see above for what the spec says about
156          * LKM_CANCEL and the lock queue state */
157         if (flags & LKM_CANCEL)
158                 status = dlm_get_cancel_actions(dlm, res, lock, lksb, &actions);
159         else
160                 status = dlm_get_unlock_actions(dlm, res, lock, lksb, &actions);
161
162         if (status != DLM_NORMAL && (status != DLM_CANCELGRANT || !master_node))
163                 goto leave;
164
165         /* By now this has been masked out of cancel requests. */
166         if (flags & LKM_VALBLK) {
167                 /* make the final update to the lvb */
168                 if (master_node)
169                         memcpy(res->lvb, lksb->lvb, DLM_LVB_LEN);
170                 else
171                         flags |= LKM_PUT_LVB; /* let the send function
172                                                * handle it. */
173         }
174
175         if (!master_node) {
176                 owner = res->owner;
177                 /* drop locks and send message */
178                 if (flags & LKM_CANCEL)
179                         lock->cancel_pending = 1;
180                 else
181                         lock->unlock_pending = 1;
182                 spin_unlock(&lock->spinlock);
183                 spin_unlock(&res->spinlock);
184                 status = dlm_send_remote_unlock_request(dlm, res, lock, lksb,
185                                                         flags, owner);
186                 spin_lock(&res->spinlock);
187                 spin_lock(&lock->spinlock);
188                 /* if the master told us the lock was already granted,
189                  * let the ast handle all of these actions */
190                 if (status == DLM_CANCELGRANT) {
191                         actions &= ~(DLM_UNLOCK_REMOVE_LOCK|
192                                      DLM_UNLOCK_REGRANT_LOCK|
193                                      DLM_UNLOCK_CLEAR_CONVERT_TYPE);
194                 } else if (status == DLM_RECOVERING || 
195                            status == DLM_MIGRATING || 
196                            status == DLM_FORWARD) {
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                               "forward"));
206                         actions = 0;
207                 }
208                 if (flags & LKM_CANCEL)
209                         lock->cancel_pending = 0;
210                 else
211                         lock->unlock_pending = 0;
212
213         }
214
215         /* get an extra ref on lock.  if we are just switching
216          * lists here, we dont want the lock to go away. */
217         dlm_lock_get(lock);
218
219         if (actions & DLM_UNLOCK_REMOVE_LOCK) {
220                 list_del_init(&lock->list);
221                 dlm_lock_put(lock);
222         }
223         if (actions & DLM_UNLOCK_REGRANT_LOCK) {
224                 dlm_lock_get(lock);
225                 list_add_tail(&lock->list, &res->granted);
226         }
227         if (actions & DLM_UNLOCK_CLEAR_CONVERT_TYPE) {
228                 mlog(0, "clearing convert_type at %smaster node\n",
229                      master_node ? "" : "non-");
230                 lock->ml.convert_type = LKM_IVMODE;
231         }
232
233         /* remove the extra ref on lock */
234         dlm_lock_put(lock);
235
236 leave:
237         res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
238         if (!dlm_lock_on_list(&res->converting, lock))
239                 BUG_ON(lock->ml.convert_type != LKM_IVMODE);
240         else
241                 BUG_ON(lock->ml.convert_type == LKM_IVMODE);
242         spin_unlock(&lock->spinlock);
243         spin_unlock(&res->spinlock);
244         wake_up(&res->wq);
245
246         /* let the caller's final dlm_lock_put handle the actual kfree */
247         if (actions & DLM_UNLOCK_FREE_LOCK) {
248                 /* this should always be coupled with list removal */
249                 BUG_ON(!(actions & DLM_UNLOCK_REMOVE_LOCK));
250                 mlog(0, "lock %u:%llu should be gone now! refs=%d\n",
251                      dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
252                      dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
253                      atomic_read(&lock->lock_refs.refcount)-1);
254                 dlm_lock_put(lock);
255         }
256         if (actions & DLM_UNLOCK_CALL_AST)
257                 *call_ast = 1;
258
259         /* if cancel or unlock succeeded, lvb work is done */
260         if (status == DLM_NORMAL)
261                 lksb->flags &= ~(DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB);
262
263         return status;
264 }
265
266 void dlm_commit_pending_unlock(struct dlm_lock_resource *res,
267                                struct dlm_lock *lock)
268 {
269         /* leave DLM_LKSB_PUT_LVB on the lksb so any final
270          * update of the lvb will be sent to the new master */
271         list_del_init(&lock->list);
272 }
273
274 void dlm_commit_pending_cancel(struct dlm_lock_resource *res,
275                                struct dlm_lock *lock)
276 {
277         list_move_tail(&lock->list, &res->granted);
278         lock->ml.convert_type = LKM_IVMODE;
279 }
280
281
282 static inline enum dlm_status dlmunlock_master(struct dlm_ctxt *dlm,
283                                           struct dlm_lock_resource *res,
284                                           struct dlm_lock *lock,
285                                           struct dlm_lockstatus *lksb,
286                                           int flags,
287                                           int *call_ast)
288 {
289         return dlmunlock_common(dlm, res, lock, lksb, flags, call_ast, 1);
290 }
291
292 static inline enum dlm_status dlmunlock_remote(struct dlm_ctxt *dlm,
293                                           struct dlm_lock_resource *res,
294                                           struct dlm_lock *lock,
295                                           struct dlm_lockstatus *lksb,
296                                           int flags, int *call_ast)
297 {
298         return dlmunlock_common(dlm, res, lock, lksb, flags, call_ast, 0);
299 }
300
301 /*
302  * locking:
303  *   caller needs:  none
304  *   taken:         none
305  *   held on exit:  none
306  * returns: DLM_NORMAL, DLM_NOLOCKMGR, status from network
307  */
308 static enum dlm_status dlm_send_remote_unlock_request(struct dlm_ctxt *dlm,
309                                                  struct dlm_lock_resource *res,
310                                                  struct dlm_lock *lock,
311                                                  struct dlm_lockstatus *lksb,
312                                                  int flags,
313                                                  u8 owner)
314 {
315         struct dlm_unlock_lock unlock;
316         int tmpret;
317         enum dlm_status ret;
318         int status = 0;
319         struct kvec vec[2];
320         size_t veclen = 1;
321
322         mlog_entry("%.*s\n", res->lockname.len, res->lockname.name);
323
324         if (owner == dlm->node_num) {
325                 /* ended up trying to contact ourself.  this means
326                  * that the lockres had been remote but became local
327                  * via a migration.  just retry it, now as local */
328                 mlog(0, "%s:%.*s: this node became the master due to a "
329                      "migration, re-evaluate now\n", dlm->name,
330                      res->lockname.len, res->lockname.name);
331                 return DLM_FORWARD;
332         }
333
334         memset(&unlock, 0, sizeof(unlock));
335         unlock.node_idx = dlm->node_num;
336         unlock.flags = cpu_to_be32(flags);
337         unlock.cookie = lock->ml.cookie;
338         unlock.namelen = res->lockname.len;
339         memcpy(unlock.name, res->lockname.name, unlock.namelen);
340
341         vec[0].iov_len = sizeof(struct dlm_unlock_lock);
342         vec[0].iov_base = &unlock;
343
344         if (flags & LKM_PUT_LVB) {
345                 /* extra data to send if we are updating lvb */
346                 vec[1].iov_len = DLM_LVB_LEN;
347                 vec[1].iov_base = lock->lksb->lvb;
348                 veclen++;
349         }
350
351         tmpret = o2net_send_message_vec(DLM_UNLOCK_LOCK_MSG, dlm->key,
352                                         vec, veclen, owner, &status);
353         if (tmpret >= 0) {
354                 // successfully sent and received
355                 if (status == DLM_FORWARD)
356                         mlog(0, "master was in-progress.  retry\n");
357                 ret = status;
358         } else {
359                 mlog_errno(tmpret);
360                 if (dlm_is_host_down(tmpret)) {
361                         /* NOTE: this seems strange, but it is what we want.
362                          * when the master goes down during a cancel or
363                          * unlock, the recovery code completes the operation
364                          * as if the master had not died, then passes the
365                          * updated state to the recovery master.  this thread
366                          * just needs to finish out the operation and call
367                          * the unlockast. */
368                         ret = DLM_NORMAL;
369                 } else {
370                         /* something bad.  this will BUG in ocfs2 */
371                         ret = dlm_err_to_dlm_status(tmpret);
372                 }
373         }
374
375         return ret;
376 }
377
378 /*
379  * locking:
380  *   caller needs:  none
381  *   taken:         takes and drops res->spinlock
382  *   held on exit:  none
383  * returns: DLM_NORMAL, DLM_BADARGS, DLM_IVLOCKID,
384  *          return value from dlmunlock_master
385  */
386 int dlm_unlock_lock_handler(struct o2net_msg *msg, u32 len, void *data,
387                             void **ret_data)
388 {
389         struct dlm_ctxt *dlm = data;
390         struct dlm_unlock_lock *unlock = (struct dlm_unlock_lock *)msg->buf;
391         struct dlm_lock_resource *res = NULL;
392         struct list_head *iter;
393         struct dlm_lock *lock = NULL;
394         enum dlm_status status = DLM_NORMAL;
395         int found = 0, i;
396         struct dlm_lockstatus *lksb = NULL;
397         int ignore;
398         u32 flags;
399         struct list_head *queue;
400
401         flags = be32_to_cpu(unlock->flags);
402
403         if (flags & LKM_GET_LVB) {
404                 mlog(ML_ERROR, "bad args!  GET_LVB specified on unlock!\n");
405                 return DLM_BADARGS;
406         }
407
408         if ((flags & (LKM_PUT_LVB|LKM_CANCEL)) == (LKM_PUT_LVB|LKM_CANCEL)) {
409                 mlog(ML_ERROR, "bad args!  cannot modify lvb on a CANCEL "
410                      "request!\n");
411                 return DLM_BADARGS;
412         }
413
414         if (unlock->namelen > DLM_LOCKID_NAME_MAX) {
415                 mlog(ML_ERROR, "Invalid name length in unlock handler!\n");
416                 return DLM_IVBUFLEN;
417         }
418
419         if (!dlm_grab(dlm))
420                 return DLM_REJECTED;
421
422         mlog_bug_on_msg(!dlm_domain_fully_joined(dlm),
423                         "Domain %s not fully joined!\n", dlm->name);
424
425         mlog(0, "lvb: %s\n", flags & LKM_PUT_LVB ? "put lvb" : "none");
426
427         res = dlm_lookup_lockres(dlm, unlock->name, unlock->namelen);
428         if (!res) {
429                 /* We assume here that a no lock resource simply means
430                  * it was migrated away and destroyed before the other
431                  * node could detect it. */
432                 mlog(0, "returning DLM_FORWARD -- res no longer exists\n");
433                 status = DLM_FORWARD;
434                 goto not_found;
435         }
436
437         queue=&res->granted;
438         found = 0;
439         spin_lock(&res->spinlock);
440         if (res->state & DLM_LOCK_RES_RECOVERING) {
441                 spin_unlock(&res->spinlock);
442                 mlog(0, "returning DLM_RECOVERING\n");
443                 status = DLM_RECOVERING;
444                 goto leave;
445         }
446
447         if (res->state & DLM_LOCK_RES_MIGRATING) {
448                 spin_unlock(&res->spinlock);
449                 mlog(0, "returning DLM_MIGRATING\n");
450                 status = DLM_MIGRATING;
451                 goto leave;
452         }
453
454         if (res->owner != dlm->node_num) {
455                 spin_unlock(&res->spinlock);
456                 mlog(0, "returning DLM_FORWARD -- not master\n");
457                 status = DLM_FORWARD;
458                 goto leave;
459         }
460
461         for (i=0; i<3; i++) {
462                 list_for_each(iter, queue) {
463                         lock = list_entry(iter, struct dlm_lock, list);
464                         if (lock->ml.cookie == unlock->cookie &&
465                             lock->ml.node == unlock->node_idx) {
466                                 dlm_lock_get(lock);
467                                 found = 1;
468                                 break;
469                         }
470                 }
471                 if (found)
472                         break;
473                 /* scan granted -> converting -> blocked queues */
474                 queue++;
475         }
476         spin_unlock(&res->spinlock);
477         if (!found) {
478                 status = DLM_IVLOCKID;
479                 goto not_found;
480         }
481
482         /* lock was found on queue */
483         lksb = lock->lksb;
484         if (flags & (LKM_VALBLK|LKM_PUT_LVB) &&
485             lock->ml.type != LKM_EXMODE)
486                 flags &= ~(LKM_VALBLK|LKM_PUT_LVB);
487
488         /* unlockast only called on originating node */
489         if (flags & LKM_PUT_LVB) {
490                 lksb->flags |= DLM_LKSB_PUT_LVB;
491                 memcpy(&lksb->lvb[0], &unlock->lvb[0], DLM_LVB_LEN);
492         }
493
494         /* if this is in-progress, propagate the DLM_FORWARD
495          * all the way back out */
496         status = dlmunlock_master(dlm, res, lock, lksb, flags, &ignore);
497         if (status == DLM_FORWARD)
498                 mlog(0, "lockres is in progress\n");
499
500         if (flags & LKM_PUT_LVB)
501                 lksb->flags &= ~DLM_LKSB_PUT_LVB;
502
503         dlm_lockres_calc_usage(dlm, res);
504         dlm_kick_thread(dlm, res);
505
506 not_found:
507         if (!found)
508                 mlog(ML_ERROR, "failed to find lock to unlock! "
509                                "cookie=%u:%llu\n",
510                      dlm_get_lock_cookie_node(be64_to_cpu(unlock->cookie)),
511                      dlm_get_lock_cookie_seq(be64_to_cpu(unlock->cookie)));
512         else
513                 dlm_lock_put(lock);
514
515 leave:
516         if (res)
517                 dlm_lockres_put(res);
518
519         dlm_put(dlm);
520
521         return status;
522 }
523
524
525 static enum dlm_status dlm_get_cancel_actions(struct dlm_ctxt *dlm,
526                                               struct dlm_lock_resource *res,
527                                               struct dlm_lock *lock,
528                                               struct dlm_lockstatus *lksb,
529                                               int *actions)
530 {
531         enum dlm_status status;
532
533         if (dlm_lock_on_list(&res->blocked, lock)) {
534                 /* cancel this outright */
535                 status = DLM_NORMAL;
536                 *actions = (DLM_UNLOCK_CALL_AST |
537                             DLM_UNLOCK_REMOVE_LOCK);
538         } else if (dlm_lock_on_list(&res->converting, lock)) {
539                 /* cancel the request, put back on granted */
540                 status = DLM_NORMAL;
541                 *actions = (DLM_UNLOCK_CALL_AST |
542                             DLM_UNLOCK_REMOVE_LOCK |
543                             DLM_UNLOCK_REGRANT_LOCK |
544                             DLM_UNLOCK_CLEAR_CONVERT_TYPE);
545         } else if (dlm_lock_on_list(&res->granted, lock)) {
546                 /* too late, already granted. */
547                 status = DLM_CANCELGRANT;
548                 *actions = DLM_UNLOCK_CALL_AST;
549         } else {
550                 mlog(ML_ERROR, "lock to cancel is not on any list!\n");
551                 status = DLM_IVLOCKID;
552                 *actions = 0;
553         }
554         return status;
555 }
556
557 static enum dlm_status dlm_get_unlock_actions(struct dlm_ctxt *dlm,
558                                               struct dlm_lock_resource *res,
559                                               struct dlm_lock *lock,
560                                               struct dlm_lockstatus *lksb,
561                                               int *actions)
562 {
563         enum dlm_status status;
564
565         /* unlock request */
566         if (!dlm_lock_on_list(&res->granted, lock)) {
567                 status = DLM_DENIED;
568                 dlm_error(status);
569                 *actions = 0;
570         } else {
571                 /* unlock granted lock */
572                 status = DLM_NORMAL;
573                 *actions = (DLM_UNLOCK_FREE_LOCK |
574                             DLM_UNLOCK_CALL_AST |
575                             DLM_UNLOCK_REMOVE_LOCK);
576         }
577         return status;
578 }
579
580 /* there seems to be no point in doing this async
581  * since (even for the remote case) there is really
582  * no work to queue up... so just do it and fire the
583  * unlockast by hand when done... */
584 enum dlm_status dlmunlock(struct dlm_ctxt *dlm, struct dlm_lockstatus *lksb,
585                           int flags, dlm_astunlockfunc_t *unlockast, void *data)
586 {
587         enum dlm_status status;
588         struct dlm_lock_resource *res;
589         struct dlm_lock *lock = NULL;
590         int call_ast, is_master;
591
592         mlog_entry_void();
593
594         if (!lksb) {
595                 dlm_error(DLM_BADARGS);
596                 return DLM_BADARGS;
597         }
598
599         if (flags & ~(LKM_CANCEL | LKM_VALBLK | LKM_INVVALBLK)) {
600                 dlm_error(DLM_BADPARAM);
601                 return DLM_BADPARAM;
602         }
603
604         if ((flags & (LKM_VALBLK | LKM_CANCEL)) == (LKM_VALBLK | LKM_CANCEL)) {
605                 mlog(0, "VALBLK given with CANCEL: ignoring VALBLK\n");
606                 flags &= ~LKM_VALBLK;
607         }
608
609         if (!lksb->lockid || !lksb->lockid->lockres) {
610                 dlm_error(DLM_BADPARAM);
611                 return DLM_BADPARAM;
612         }
613
614         lock = lksb->lockid;
615         BUG_ON(!lock);
616         dlm_lock_get(lock);
617
618         res = lock->lockres;
619         BUG_ON(!res);
620         dlm_lockres_get(res);
621 retry:
622         call_ast = 0;
623         /* need to retry up here because owner may have changed */
624         mlog(0, "lock=%p res=%p\n", lock, res);
625
626         spin_lock(&res->spinlock);
627         is_master = (res->owner == dlm->node_num);
628         if (flags & LKM_VALBLK && lock->ml.type != LKM_EXMODE)
629                 flags &= ~LKM_VALBLK;
630         spin_unlock(&res->spinlock);
631
632         if (is_master) {
633                 status = dlmunlock_master(dlm, res, lock, lksb, flags,
634                                           &call_ast);
635                 mlog(0, "done calling dlmunlock_master: returned %d, "
636                      "call_ast is %d\n", status, call_ast);
637         } else {
638                 status = dlmunlock_remote(dlm, res, lock, lksb, flags,
639                                           &call_ast);
640                 mlog(0, "done calling dlmunlock_remote: returned %d, "
641                      "call_ast is %d\n", status, call_ast);
642         }
643
644         if (status == DLM_RECOVERING ||
645             status == DLM_MIGRATING ||
646             status == DLM_FORWARD) {
647                 /* We want to go away for a tiny bit to allow recovery
648                  * / migration to complete on this resource. I don't
649                  * know of any wait queue we could sleep on as this
650                  * may be happening on another node. Perhaps the
651                  * proper solution is to queue up requests on the
652                  * other end? */
653
654                 /* do we want to yield(); ?? */
655                 msleep(50);
656
657                 mlog(0, "retrying unlock due to pending recovery/"
658                      "migration/in-progress\n");
659                 goto retry;
660         }
661
662         if (call_ast) {
663                 mlog(0, "calling unlockast(%p, %d)\n", data, status);
664                 if (is_master) {
665                         /* it is possible that there is one last bast 
666                          * pending.  make sure it is flushed, then
667                          * call the unlockast.
668                          * not an issue if this is a mastered remotely,
669                          * since this lock has been removed from the
670                          * lockres queues and cannot be found. */
671                         dlm_kick_thread(dlm, NULL);
672                         wait_event(dlm->ast_wq, 
673                                    dlm_lock_basts_flushed(dlm, lock));
674                 }
675                 (*unlockast)(data, status);
676         }
677
678         if (status == DLM_CANCELGRANT)
679                 status = DLM_NORMAL;
680
681         if (status == DLM_NORMAL) {
682                 mlog(0, "kicking the thread\n");
683                 dlm_kick_thread(dlm, res);
684         } else
685                 dlm_error(status);
686
687         dlm_lockres_calc_usage(dlm, res);
688         dlm_lockres_put(res);
689         dlm_lock_put(lock);
690
691         mlog(0, "returning status=%d!\n", status);
692         return status;
693 }
694 EXPORT_SYMBOL_GPL(dlmunlock);
695