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TOMOYO Linux Cross Reference
Linux/fs/ocfs2/dlm/dlmunlock.c

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  1 // SPDX-License-Identifier: GPL-2.0-or-later
  2 /*
  3  * dlmunlock.c
  4  *
  5  * underlying calls for unlocking locks
  6  *
  7  * Copyright (C) 2004 Oracle.  All rights reserved.
  8  */
  9 
 10 
 11 #include <linux/module.h>
 12 #include <linux/fs.h>
 13 #include <linux/types.h>
 14 #include <linux/highmem.h>
 15 #include <linux/init.h>
 16 #include <linux/sysctl.h>
 17 #include <linux/random.h>
 18 #include <linux/blkdev.h>
 19 #include <linux/socket.h>
 20 #include <linux/inet.h>
 21 #include <linux/spinlock.h>
 22 #include <linux/delay.h>
 23 
 24 #include "../cluster/heartbeat.h"
 25 #include "../cluster/nodemanager.h"
 26 #include "../cluster/tcp.h"
 27 
 28 #include "dlmapi.h"
 29 #include "dlmcommon.h"
 30 
 31 #define MLOG_MASK_PREFIX ML_DLM
 32 #include "../cluster/masklog.h"
 33 
 34 #define DLM_UNLOCK_FREE_LOCK           0x00000001
 35 #define DLM_UNLOCK_CALL_AST            0x00000002
 36 #define DLM_UNLOCK_REMOVE_LOCK         0x00000004
 37 #define DLM_UNLOCK_REGRANT_LOCK        0x00000008
 38 #define DLM_UNLOCK_CLEAR_CONVERT_TYPE  0x00000010
 39 
 40 
 41 static enum dlm_status dlm_get_cancel_actions(struct dlm_ctxt *dlm,
 42                                               struct dlm_lock_resource *res,
 43                                               struct dlm_lock *lock,
 44                                               struct dlm_lockstatus *lksb,
 45                                               int *actions);
 46 static enum dlm_status dlm_get_unlock_actions(struct dlm_ctxt *dlm,
 47                                               struct dlm_lock_resource *res,
 48                                               struct dlm_lock *lock,
 49                                               struct dlm_lockstatus *lksb,
 50                                               int *actions);
 51 
 52 static enum dlm_status dlm_send_remote_unlock_request(struct dlm_ctxt *dlm,
 53                                                  struct dlm_lock_resource *res,
 54                                                  struct dlm_lock *lock,
 55                                                  struct dlm_lockstatus *lksb,
 56                                                  int flags,
 57                                                  u8 owner);
 58 
 59 
 60 /*
 61  * according to the spec:
 62  * http://opendlm.sourceforge.net/cvsmirror/opendlm/docs/dlmbook_final.pdf
 63  *
 64  *  flags & LKM_CANCEL != 0: must be converting or blocked
 65  *  flags & LKM_CANCEL == 0: must be granted
 66  *
 67  * So to unlock a converting lock, you must first cancel the
 68  * convert (passing LKM_CANCEL in flags), then call the unlock
 69  * again (with no LKM_CANCEL in flags).
 70  */
 71 
 72 
 73 /*
 74  * locking:
 75  *   caller needs:  none
 76  *   taken:         res->spinlock and lock->spinlock taken and dropped
 77  *   held on exit:  none
 78  * returns: DLM_NORMAL, DLM_NOLOCKMGR, status from network
 79  * all callers should have taken an extra ref on lock coming in
 80  */
 81 static enum dlm_status dlmunlock_common(struct dlm_ctxt *dlm,
 82                                         struct dlm_lock_resource *res,
 83                                         struct dlm_lock *lock,
 84                                         struct dlm_lockstatus *lksb,
 85                                         int flags, int *call_ast,
 86                                         int master_node)
 87 {
 88         enum dlm_status status;
 89         int actions = 0;
 90         int in_use;
 91         u8 owner;
 92         int recovery_wait = 0;
 93 
 94         mlog(0, "master_node = %d, valblk = %d\n", master_node,
 95              flags & LKM_VALBLK);
 96 
 97         if (master_node)
 98                 BUG_ON(res->owner != dlm->node_num);
 99         else
100                 BUG_ON(res->owner == dlm->node_num);
101 
102         spin_lock(&dlm->ast_lock);
103         /* We want to be sure that we're not freeing a lock
104          * that still has AST's pending... */
105         in_use = !list_empty(&lock->ast_list);
106         spin_unlock(&dlm->ast_lock);
107         if (in_use && !(flags & LKM_CANCEL)) {
108                mlog(ML_ERROR, "lockres %.*s: Someone is calling dlmunlock "
109                     "while waiting for an ast!", res->lockname.len,
110                     res->lockname.name);
111                 return DLM_BADPARAM;
112         }
113 
114         spin_lock(&res->spinlock);
115         if (res->state & DLM_LOCK_RES_IN_PROGRESS) {
116                 if (master_node && !(flags & LKM_CANCEL)) {
117                         mlog(ML_ERROR, "lockres in progress!\n");
118                         spin_unlock(&res->spinlock);
119                         return DLM_FORWARD;
120                 }
121                 /* ok for this to sleep if not in a network handler */
122                 __dlm_wait_on_lockres(res);
123                 res->state |= DLM_LOCK_RES_IN_PROGRESS;
124         }
125         spin_lock(&lock->spinlock);
126 
127         if (res->state & DLM_LOCK_RES_RECOVERING) {
128                 status = DLM_RECOVERING;
129                 goto leave;
130         }
131 
132         if (res->state & DLM_LOCK_RES_MIGRATING) {
133                 status = DLM_MIGRATING;
134                 goto leave;
135         }
136 
137         /* see above for what the spec says about
138          * LKM_CANCEL and the lock queue state */
139         if (flags & LKM_CANCEL)
140                 status = dlm_get_cancel_actions(dlm, res, lock, lksb, &actions);
141         else
142                 status = dlm_get_unlock_actions(dlm, res, lock, lksb, &actions);
143 
144         if (status != DLM_NORMAL && (status != DLM_CANCELGRANT || !master_node))
145                 goto leave;
146 
147         /* By now this has been masked out of cancel requests. */
148         if (flags & LKM_VALBLK) {
149                 /* make the final update to the lvb */
150                 if (master_node)
151                         memcpy(res->lvb, lksb->lvb, DLM_LVB_LEN);
152                 else
153                         flags |= LKM_PUT_LVB; /* let the send function
154                                                * handle it. */
155         }
156 
157         if (!master_node) {
158                 owner = res->owner;
159                 /* drop locks and send message */
160                 if (flags & LKM_CANCEL)
161                         lock->cancel_pending = 1;
162                 else
163                         lock->unlock_pending = 1;
164                 spin_unlock(&lock->spinlock);
165                 spin_unlock(&res->spinlock);
166                 status = dlm_send_remote_unlock_request(dlm, res, lock, lksb,
167                                                         flags, owner);
168                 spin_lock(&res->spinlock);
169                 spin_lock(&lock->spinlock);
170                 /* if the master told us the lock was already granted,
171                  * let the ast handle all of these actions */
172                 if (status == DLM_CANCELGRANT) {
173                         actions &= ~(DLM_UNLOCK_REMOVE_LOCK|
174                                      DLM_UNLOCK_REGRANT_LOCK|
175                                      DLM_UNLOCK_CLEAR_CONVERT_TYPE);
176                 } else if (status == DLM_RECOVERING ||
177                            status == DLM_MIGRATING ||
178                            status == DLM_FORWARD ||
179                            status == DLM_NOLOCKMGR
180                            ) {
181                         /* must clear the actions because this unlock
182                          * is about to be retried.  cannot free or do
183                          * any list manipulation. */
184                         mlog(0, "%s:%.*s: clearing actions, %s\n",
185                              dlm->name, res->lockname.len,
186                              res->lockname.name,
187                              status==DLM_RECOVERING?"recovering":
188                              (status==DLM_MIGRATING?"migrating":
189                                 (status == DLM_FORWARD ? "forward" :
190                                                 "nolockmanager")));
191                         actions = 0;
192                 }
193                 if (flags & LKM_CANCEL)
194                         lock->cancel_pending = 0;
195                 else {
196                         if (!lock->unlock_pending)
197                                 recovery_wait = 1;
198                         else
199                                 lock->unlock_pending = 0;
200                 }
201         }
202 
203         /* get an extra ref on lock.  if we are just switching
204          * lists here, we dont want the lock to go away. */
205         dlm_lock_get(lock);
206 
207         if (actions & DLM_UNLOCK_REMOVE_LOCK) {
208                 list_del_init(&lock->list);
209                 dlm_lock_put(lock);
210         }
211         if (actions & DLM_UNLOCK_REGRANT_LOCK) {
212                 dlm_lock_get(lock);
213                 list_add_tail(&lock->list, &res->granted);
214         }
215         if (actions & DLM_UNLOCK_CLEAR_CONVERT_TYPE) {
216                 mlog(0, "clearing convert_type at %smaster node\n",
217                      master_node ? "" : "non-");
218                 lock->ml.convert_type = LKM_IVMODE;
219         }
220 
221         /* remove the extra ref on lock */
222         dlm_lock_put(lock);
223 
224 leave:
225         res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
226         if (!dlm_lock_on_list(&res->converting, lock))
227                 BUG_ON(lock->ml.convert_type != LKM_IVMODE);
228         else
229                 BUG_ON(lock->ml.convert_type == LKM_IVMODE);
230         spin_unlock(&lock->spinlock);
231         spin_unlock(&res->spinlock);
232         wake_up(&res->wq);
233 
234         if (recovery_wait) {
235                 spin_lock(&res->spinlock);
236                 /* Unlock request will directly succeed after owner dies,
237                  * and the lock is already removed from grant list. We have to
238                  * wait for RECOVERING done or we miss the chance to purge it
239                  * since the removement is much faster than RECOVERING proc.
240                  */
241                 __dlm_wait_on_lockres_flags(res, DLM_LOCK_RES_RECOVERING);
242                 spin_unlock(&res->spinlock);
243         }
244 
245         /* let the caller's final dlm_lock_put handle the actual kfree */
246         if (actions & DLM_UNLOCK_FREE_LOCK) {
247                 /* this should always be coupled with list removal */
248                 BUG_ON(!(actions & DLM_UNLOCK_REMOVE_LOCK));
249                 mlog(0, "lock %u:%llu should be gone now! refs=%d\n",
250                      dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
251                      dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
252                      kref_read(&lock->lock_refs)-1);
253                 dlm_lock_put(lock);
254         }
255         if (actions & DLM_UNLOCK_CALL_AST)
256                 *call_ast = 1;
257 
258         /* if cancel or unlock succeeded, lvb work is done */
259         if (status == DLM_NORMAL)
260                 lksb->flags &= ~(DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB);
261 
262         return status;
263 }
264 
265 void dlm_commit_pending_unlock(struct dlm_lock_resource *res,
266                                struct dlm_lock *lock)
267 {
268         /* leave DLM_LKSB_PUT_LVB on the lksb so any final
269          * update of the lvb will be sent to the new master */
270         list_del_init(&lock->list);
271 }
272 
273 void dlm_commit_pending_cancel(struct dlm_lock_resource *res,
274                                struct dlm_lock *lock)
275 {
276         list_move_tail(&lock->list, &res->granted);
277         lock->ml.convert_type = LKM_IVMODE;
278 }
279 
280 
281 static inline enum dlm_status dlmunlock_master(struct dlm_ctxt *dlm,
282                                           struct dlm_lock_resource *res,
283                                           struct dlm_lock *lock,
284                                           struct dlm_lockstatus *lksb,
285                                           int flags,
286                                           int *call_ast)
287 {
288         return dlmunlock_common(dlm, res, lock, lksb, flags, call_ast, 1);
289 }
290 
291 static inline enum dlm_status dlmunlock_remote(struct dlm_ctxt *dlm,
292                                           struct dlm_lock_resource *res,
293                                           struct dlm_lock *lock,
294                                           struct dlm_lockstatus *lksb,
295                                           int flags, int *call_ast)
296 {
297         return dlmunlock_common(dlm, res, lock, lksb, flags, call_ast, 0);
298 }
299 
300 /*
301  * locking:
302  *   caller needs:  none
303  *   taken:         none
304  *   held on exit:  none
305  * returns: DLM_NORMAL, DLM_NOLOCKMGR, status from network
306  */
307 static enum dlm_status dlm_send_remote_unlock_request(struct dlm_ctxt *dlm,
308                                                  struct dlm_lock_resource *res,
309                                                  struct dlm_lock *lock,
310                                                  struct dlm_lockstatus *lksb,
311                                                  int flags,
312                                                  u8 owner)
313 {
314         struct dlm_unlock_lock unlock;
315         int tmpret;
316         enum dlm_status ret;
317         int status = 0;
318         struct kvec vec[2];
319         size_t veclen = 1;
320 
321         mlog(0, "%.*s\n", res->lockname.len, res->lockname.name);
322 
323         if (owner == dlm->node_num) {
324                 /* ended up trying to contact ourself.  this means
325                  * that the lockres had been remote but became local
326                  * via a migration.  just retry it, now as local */
327                 mlog(0, "%s:%.*s: this node became the master due to a "
328                      "migration, re-evaluate now\n", dlm->name,
329                      res->lockname.len, res->lockname.name);
330                 return DLM_FORWARD;
331         }
332 
333         memset(&unlock, 0, sizeof(unlock));
334         unlock.node_idx = dlm->node_num;
335         unlock.flags = cpu_to_be32(flags);
336         unlock.cookie = lock->ml.cookie;
337         unlock.namelen = res->lockname.len;
338         memcpy(unlock.name, res->lockname.name, unlock.namelen);
339 
340         vec[0].iov_len = sizeof(struct dlm_unlock_lock);
341         vec[0].iov_base = &unlock;
342 
343         if (flags & LKM_PUT_LVB) {
344                 /* extra data to send if we are updating lvb */
345                 vec[1].iov_len = DLM_LVB_LEN;
346                 vec[1].iov_base = lock->lksb->lvb;
347                 veclen++;
348         }
349 
350         tmpret = o2net_send_message_vec(DLM_UNLOCK_LOCK_MSG, dlm->key,
351                                         vec, veclen, owner, &status);
352         if (tmpret >= 0) {
353                 // successfully sent and received
354                 if (status == DLM_FORWARD)
355                         mlog(0, "master was in-progress.  retry\n");
356                 ret = status;
357         } else {
358                 mlog(ML_ERROR, "Error %d when sending message %u (key 0x%x) to "
359                      "node %u\n", tmpret, DLM_UNLOCK_LOCK_MSG, dlm->key, owner);
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                         if (dlm_is_node_dead(dlm, owner))
369                                 ret = DLM_NORMAL;
370                         else
371                                 ret = DLM_NOLOCKMGR;
372                 } else {
373                         /* something bad.  this will BUG in ocfs2 */
374                         ret = dlm_err_to_dlm_status(tmpret);
375                 }
376         }
377 
378         return ret;
379 }
380 
381 /*
382  * locking:
383  *   caller needs:  none
384  *   taken:         takes and drops res->spinlock
385  *   held on exit:  none
386  * returns: DLM_NORMAL, DLM_BADARGS, DLM_IVLOCKID,
387  *          return value from dlmunlock_master
388  */
389 int dlm_unlock_lock_handler(struct o2net_msg *msg, u32 len, void *data,
390                             void **ret_data)
391 {
392         struct dlm_ctxt *dlm = data;
393         struct dlm_unlock_lock *unlock = (struct dlm_unlock_lock *)msg->buf;
394         struct dlm_lock_resource *res = NULL;
395         struct dlm_lock *lock = NULL, *iter;
396         enum dlm_status status = DLM_NORMAL;
397         int i;
398         struct dlm_lockstatus *lksb = NULL;
399         int ignore;
400         u32 flags;
401         struct list_head *queue;
402 
403         flags = be32_to_cpu(unlock->flags);
404 
405         if (flags & LKM_GET_LVB) {
406                 mlog(ML_ERROR, "bad args!  GET_LVB specified on unlock!\n");
407                 return DLM_BADARGS;
408         }
409 
410         if ((flags & (LKM_PUT_LVB|LKM_CANCEL)) == (LKM_PUT_LVB|LKM_CANCEL)) {
411                 mlog(ML_ERROR, "bad args!  cannot modify lvb on a CANCEL "
412                      "request!\n");
413                 return DLM_BADARGS;
414         }
415 
416         if (unlock->namelen > DLM_LOCKID_NAME_MAX) {
417                 mlog(ML_ERROR, "Invalid name length in unlock handler!\n");
418                 return DLM_IVBUFLEN;
419         }
420 
421         if (!dlm_grab(dlm))
422                 return DLM_FORWARD;
423 
424         mlog_bug_on_msg(!dlm_domain_fully_joined(dlm),
425                         "Domain %s not fully joined!\n", dlm->name);
426 
427         mlog(0, "lvb: %s\n", flags & LKM_PUT_LVB ? "put lvb" : "none");
428 
429         res = dlm_lookup_lockres(dlm, unlock->name, unlock->namelen);
430         if (!res) {
431                 /* We assume here that a no lock resource simply means
432                  * it was migrated away and destroyed before the other
433                  * node could detect it. */
434                 mlog(0, "returning DLM_FORWARD -- res no longer exists\n");
435                 status = DLM_FORWARD;
436                 goto not_found;
437         }
438 
439         queue=&res->granted;
440         spin_lock(&res->spinlock);
441         if (res->state & DLM_LOCK_RES_RECOVERING) {
442                 spin_unlock(&res->spinlock);
443                 mlog(0, "returning DLM_RECOVERING\n");
444                 status = DLM_RECOVERING;
445                 goto leave;
446         }
447 
448         if (res->state & DLM_LOCK_RES_MIGRATING) {
449                 spin_unlock(&res->spinlock);
450                 mlog(0, "returning DLM_MIGRATING\n");
451                 status = DLM_MIGRATING;
452                 goto leave;
453         }
454 
455         if (res->owner != dlm->node_num) {
456                 spin_unlock(&res->spinlock);
457                 mlog(0, "returning DLM_FORWARD -- not master\n");
458                 status = DLM_FORWARD;
459                 goto leave;
460         }
461 
462         for (i=0; i<3; i++) {
463                 list_for_each_entry(iter, queue, list) {
464                         if (iter->ml.cookie == unlock->cookie &&
465                             iter->ml.node == unlock->node_idx) {
466                                 dlm_lock_get(iter);
467                                 lock = iter;
468                                 break;
469                         }
470                 }
471                 if (lock)
472                         break;
473                 /* scan granted -> converting -> blocked queues */
474                 queue++;
475         }
476         spin_unlock(&res->spinlock);
477         if (!lock) {
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 (!lock)
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         if (!lksb) {
593                 dlm_error(DLM_BADARGS);
594                 return DLM_BADARGS;
595         }
596 
597         if (flags & ~(LKM_CANCEL | LKM_VALBLK | LKM_INVVALBLK)) {
598                 dlm_error(DLM_BADPARAM);
599                 return DLM_BADPARAM;
600         }
601 
602         if ((flags & (LKM_VALBLK | LKM_CANCEL)) == (LKM_VALBLK | LKM_CANCEL)) {
603                 mlog(0, "VALBLK given with CANCEL: ignoring VALBLK\n");
604                 flags &= ~LKM_VALBLK;
605         }
606 
607         if (!lksb->lockid || !lksb->lockid->lockres) {
608                 dlm_error(DLM_BADPARAM);
609                 return DLM_BADPARAM;
610         }
611 
612         lock = lksb->lockid;
613         BUG_ON(!lock);
614         dlm_lock_get(lock);
615 
616         res = lock->lockres;
617         BUG_ON(!res);
618         dlm_lockres_get(res);
619 retry:
620         call_ast = 0;
621         /* need to retry up here because owner may have changed */
622         mlog(0, "lock=%p res=%p\n", lock, res);
623 
624         spin_lock(&res->spinlock);
625         is_master = (res->owner == dlm->node_num);
626         if (flags & LKM_VALBLK && lock->ml.type != LKM_EXMODE)
627                 flags &= ~LKM_VALBLK;
628         spin_unlock(&res->spinlock);
629 
630         if (is_master) {
631                 status = dlmunlock_master(dlm, res, lock, lksb, flags,
632                                           &call_ast);
633                 mlog(0, "done calling dlmunlock_master: returned %d, "
634                      "call_ast is %d\n", status, call_ast);
635         } else {
636                 status = dlmunlock_remote(dlm, res, lock, lksb, flags,
637                                           &call_ast);
638                 mlog(0, "done calling dlmunlock_remote: returned %d, "
639                      "call_ast is %d\n", status, call_ast);
640         }
641 
642         if (status == DLM_RECOVERING ||
643             status == DLM_MIGRATING ||
644             status == DLM_FORWARD ||
645             status == DLM_NOLOCKMGR) {
646 
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/reconnect\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 
696 

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