Merge master.kernel.org:/home/rmk/linux-2.6-arm
[linux-2.6] / fs / ocfs2 / dlm / dlmlock.c
1 /* -*- mode: c; c-basic-offset: 8; -*-
2  * vim: noexpandtab sw=8 ts=8 sts=0:
3  *
4  * dlmlock.c
5  *
6  * underlying calls for lock creation
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
44 #include "cluster/heartbeat.h"
45 #include "cluster/nodemanager.h"
46 #include "cluster/tcp.h"
47
48 #include "dlmapi.h"
49 #include "dlmcommon.h"
50
51 #include "dlmconvert.h"
52
53 #define MLOG_MASK_PREFIX ML_DLM
54 #include "cluster/masklog.h"
55
56 static spinlock_t dlm_cookie_lock = SPIN_LOCK_UNLOCKED;
57 static u64 dlm_next_cookie = 1;
58
59 static enum dlm_status dlm_send_remote_lock_request(struct dlm_ctxt *dlm,
60                                                struct dlm_lock_resource *res,
61                                                struct dlm_lock *lock, int flags);
62 static void dlm_init_lock(struct dlm_lock *newlock, int type,
63                           u8 node, u64 cookie);
64 static void dlm_lock_release(struct kref *kref);
65 static void dlm_lock_detach_lockres(struct dlm_lock *lock);
66
67 /* Tell us whether we can grant a new lock request.
68  * locking:
69  *   caller needs:  res->spinlock
70  *   taken:         none
71  *   held on exit:  none
72  * returns: 1 if the lock can be granted, 0 otherwise.
73  */
74 static int dlm_can_grant_new_lock(struct dlm_lock_resource *res,
75                                   struct dlm_lock *lock)
76 {
77         struct list_head *iter;
78         struct dlm_lock *tmplock;
79
80         list_for_each(iter, &res->granted) {
81                 tmplock = list_entry(iter, struct dlm_lock, list);
82
83                 if (!dlm_lock_compatible(tmplock->ml.type, lock->ml.type))
84                         return 0;
85         }
86
87         list_for_each(iter, &res->converting) {
88                 tmplock = list_entry(iter, struct dlm_lock, list);
89
90                 if (!dlm_lock_compatible(tmplock->ml.type, lock->ml.type))
91                         return 0;
92         }
93
94         return 1;
95 }
96
97 /* performs lock creation at the lockres master site
98  * locking:
99  *   caller needs:  none
100  *   taken:         takes and drops res->spinlock
101  *   held on exit:  none
102  * returns: DLM_NORMAL, DLM_NOTQUEUED
103  */
104 static enum dlm_status dlmlock_master(struct dlm_ctxt *dlm,
105                                       struct dlm_lock_resource *res,
106                                       struct dlm_lock *lock, int flags)
107 {
108         int call_ast = 0, kick_thread = 0;
109         enum dlm_status status = DLM_NORMAL;
110
111         mlog_entry("type=%d\n", lock->ml.type);
112
113         spin_lock(&res->spinlock);
114         /* if called from dlm_create_lock_handler, need to
115          * ensure it will not sleep in dlm_wait_on_lockres */
116         status = __dlm_lockres_state_to_status(res);
117         if (status != DLM_NORMAL &&
118             lock->ml.node != dlm->node_num) {
119                 /* erf.  state changed after lock was dropped. */
120                 spin_unlock(&res->spinlock);
121                 dlm_error(status);
122                 return status;
123         }
124         __dlm_wait_on_lockres(res);
125         __dlm_lockres_reserve_ast(res);
126
127         if (dlm_can_grant_new_lock(res, lock)) {
128                 mlog(0, "I can grant this lock right away\n");
129                 /* got it right away */
130                 lock->lksb->status = DLM_NORMAL;
131                 status = DLM_NORMAL;
132                 dlm_lock_get(lock);
133                 list_add_tail(&lock->list, &res->granted);
134
135                 /* for the recovery lock, we can't allow the ast
136                  * to be queued since the dlmthread is already
137                  * frozen.  but the recovery lock is always locked
138                  * with LKM_NOQUEUE so we do not need the ast in
139                  * this special case */
140                 if (!dlm_is_recovery_lock(res->lockname.name,
141                                           res->lockname.len)) {
142                         kick_thread = 1;
143                         call_ast = 1;
144                 } else {
145                         mlog(0, "%s: returning DLM_NORMAL to "
146                              "node %u for reco lock\n", dlm->name,
147                              lock->ml.node);
148                 }
149         } else {
150                 /* for NOQUEUE request, unless we get the
151                  * lock right away, return DLM_NOTQUEUED */
152                 if (flags & LKM_NOQUEUE) {
153                         status = DLM_NOTQUEUED;
154                         if (dlm_is_recovery_lock(res->lockname.name,
155                                                  res->lockname.len)) {
156                                 mlog(0, "%s: returning NOTQUEUED to "
157                                      "node %u for reco lock\n", dlm->name,
158                                      lock->ml.node);
159                         }
160                 } else {
161                         dlm_lock_get(lock);
162                         list_add_tail(&lock->list, &res->blocked);
163                         kick_thread = 1;
164                 }
165         }
166
167         spin_unlock(&res->spinlock);
168         wake_up(&res->wq);
169
170         /* either queue the ast or release it */
171         if (call_ast)
172                 dlm_queue_ast(dlm, lock);
173         else
174                 dlm_lockres_release_ast(dlm, res);
175
176         dlm_lockres_calc_usage(dlm, res);
177         if (kick_thread)
178                 dlm_kick_thread(dlm, res);
179
180         return status;
181 }
182
183 void dlm_revert_pending_lock(struct dlm_lock_resource *res,
184                              struct dlm_lock *lock)
185 {
186         /* remove from local queue if it failed */
187         list_del_init(&lock->list);
188         lock->lksb->flags &= ~DLM_LKSB_GET_LVB;
189 }
190
191
192 /*
193  * locking:
194  *   caller needs:  none
195  *   taken:         takes and drops res->spinlock
196  *   held on exit:  none
197  * returns: DLM_DENIED, DLM_RECOVERING, or net status
198  */
199 static enum dlm_status dlmlock_remote(struct dlm_ctxt *dlm,
200                                       struct dlm_lock_resource *res,
201                                       struct dlm_lock *lock, int flags)
202 {
203         enum dlm_status status = DLM_DENIED;
204
205         mlog_entry("type=%d\n", lock->ml.type);
206         mlog(0, "lockres %.*s, flags = 0x%x\n", res->lockname.len,
207              res->lockname.name, flags);
208
209         spin_lock(&res->spinlock);
210
211         /* will exit this call with spinlock held */
212         __dlm_wait_on_lockres(res);
213         res->state |= DLM_LOCK_RES_IN_PROGRESS;
214
215         /* add lock to local (secondary) queue */
216         dlm_lock_get(lock);
217         list_add_tail(&lock->list, &res->blocked);
218         lock->lock_pending = 1;
219         spin_unlock(&res->spinlock);
220
221         /* spec seems to say that you will get DLM_NORMAL when the lock
222          * has been queued, meaning we need to wait for a reply here. */
223         status = dlm_send_remote_lock_request(dlm, res, lock, flags);
224
225         spin_lock(&res->spinlock);
226         res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
227         lock->lock_pending = 0;
228         if (status != DLM_NORMAL) {
229                 if (status != DLM_NOTQUEUED)
230                         dlm_error(status);
231                 dlm_revert_pending_lock(res, lock);
232                 dlm_lock_put(lock);
233         } else if (dlm_is_recovery_lock(res->lockname.name, 
234                                         res->lockname.len)) {
235                 /* special case for the $RECOVERY lock.
236                  * there will never be an AST delivered to put
237                  * this lock on the proper secondary queue
238                  * (granted), so do it manually. */
239                 mlog(0, "%s: $RECOVERY lock for this node (%u) is "
240                      "mastered by %u; got lock, manually granting (no ast)\n",
241                      dlm->name, dlm->node_num, res->owner);
242                 list_del_init(&lock->list);
243                 list_add_tail(&lock->list, &res->granted);
244         }
245         spin_unlock(&res->spinlock);
246
247         dlm_lockres_calc_usage(dlm, res);
248
249         wake_up(&res->wq);
250         return status;
251 }
252
253
254 /* for remote lock creation.
255  * locking:
256  *   caller needs:  none, but need res->state & DLM_LOCK_RES_IN_PROGRESS
257  *   taken:         none
258  *   held on exit:  none
259  * returns: DLM_NOLOCKMGR, or net status
260  */
261 static enum dlm_status dlm_send_remote_lock_request(struct dlm_ctxt *dlm,
262                                                struct dlm_lock_resource *res,
263                                                struct dlm_lock *lock, int flags)
264 {
265         struct dlm_create_lock create;
266         int tmpret, status = 0;
267         enum dlm_status ret;
268
269         mlog_entry_void();
270
271         memset(&create, 0, sizeof(create));
272         create.node_idx = dlm->node_num;
273         create.requested_type = lock->ml.type;
274         create.cookie = lock->ml.cookie;
275         create.namelen = res->lockname.len;
276         create.flags = cpu_to_be32(flags);
277         memcpy(create.name, res->lockname.name, create.namelen);
278
279         tmpret = o2net_send_message(DLM_CREATE_LOCK_MSG, dlm->key, &create,
280                                     sizeof(create), res->owner, &status);
281         if (tmpret >= 0) {
282                 // successfully sent and received
283                 ret = status;  // this is already a dlm_status
284         } else {
285                 mlog_errno(tmpret);
286                 if (dlm_is_host_down(tmpret)) {
287                         ret = DLM_RECOVERING;
288                         mlog(0, "node %u died so returning DLM_RECOVERING "
289                              "from lock message!\n", res->owner);
290                 } else {
291                         ret = dlm_err_to_dlm_status(tmpret);
292                 }
293         }
294
295         return ret;
296 }
297
298 void dlm_lock_get(struct dlm_lock *lock)
299 {
300         kref_get(&lock->lock_refs);
301 }
302
303 void dlm_lock_put(struct dlm_lock *lock)
304 {
305         kref_put(&lock->lock_refs, dlm_lock_release);
306 }
307
308 static void dlm_lock_release(struct kref *kref)
309 {
310         struct dlm_lock *lock;
311
312         lock = container_of(kref, struct dlm_lock, lock_refs);
313
314         BUG_ON(!list_empty(&lock->list));
315         BUG_ON(!list_empty(&lock->ast_list));
316         BUG_ON(!list_empty(&lock->bast_list));
317         BUG_ON(lock->ast_pending);
318         BUG_ON(lock->bast_pending);
319
320         dlm_lock_detach_lockres(lock);
321
322         if (lock->lksb_kernel_allocated) {
323                 mlog(0, "freeing kernel-allocated lksb\n");
324                 kfree(lock->lksb);
325         }
326         kfree(lock);
327 }
328
329 /* associate a lock with it's lockres, getting a ref on the lockres */
330 void dlm_lock_attach_lockres(struct dlm_lock *lock,
331                              struct dlm_lock_resource *res)
332 {
333         dlm_lockres_get(res);
334         lock->lockres = res;
335 }
336
337 /* drop ref on lockres, if there is still one associated with lock */
338 static void dlm_lock_detach_lockres(struct dlm_lock *lock)
339 {
340         struct dlm_lock_resource *res;
341
342         res = lock->lockres;
343         if (res) {
344                 lock->lockres = NULL;
345                 mlog(0, "removing lock's lockres reference\n");
346                 dlm_lockres_put(res);
347         }
348 }
349
350 static void dlm_init_lock(struct dlm_lock *newlock, int type,
351                           u8 node, u64 cookie)
352 {
353         INIT_LIST_HEAD(&newlock->list);
354         INIT_LIST_HEAD(&newlock->ast_list);
355         INIT_LIST_HEAD(&newlock->bast_list);
356         spin_lock_init(&newlock->spinlock);
357         newlock->ml.type = type;
358         newlock->ml.convert_type = LKM_IVMODE;
359         newlock->ml.highest_blocked = LKM_IVMODE;
360         newlock->ml.node = node;
361         newlock->ml.pad1 = 0;
362         newlock->ml.list = 0;
363         newlock->ml.flags = 0;
364         newlock->ast = NULL;
365         newlock->bast = NULL;
366         newlock->astdata = NULL;
367         newlock->ml.cookie = cpu_to_be64(cookie);
368         newlock->ast_pending = 0;
369         newlock->bast_pending = 0;
370         newlock->convert_pending = 0;
371         newlock->lock_pending = 0;
372         newlock->unlock_pending = 0;
373         newlock->cancel_pending = 0;
374         newlock->lksb_kernel_allocated = 0;
375
376         kref_init(&newlock->lock_refs);
377 }
378
379 struct dlm_lock * dlm_new_lock(int type, u8 node, u64 cookie,
380                                struct dlm_lockstatus *lksb)
381 {
382         struct dlm_lock *lock;
383         int kernel_allocated = 0;
384
385         lock = kcalloc(1, sizeof(*lock), GFP_KERNEL);
386         if (!lock)
387                 return NULL;
388
389         if (!lksb) {
390                 /* zero memory only if kernel-allocated */
391                 lksb = kcalloc(1, sizeof(*lksb), GFP_KERNEL);
392                 if (!lksb) {
393                         kfree(lock);
394                         return NULL;
395                 }
396                 kernel_allocated = 1;
397         }
398
399         dlm_init_lock(lock, type, node, cookie);
400         if (kernel_allocated)
401                 lock->lksb_kernel_allocated = 1;
402         lock->lksb = lksb;
403         lksb->lockid = lock;
404         return lock;
405 }
406
407 /* handler for lock creation net message
408  * locking:
409  *   caller needs:  none
410  *   taken:         takes and drops res->spinlock
411  *   held on exit:  none
412  * returns: DLM_NORMAL, DLM_SYSERR, DLM_IVLOCKID, DLM_NOTQUEUED
413  */
414 int dlm_create_lock_handler(struct o2net_msg *msg, u32 len, void *data)
415 {
416         struct dlm_ctxt *dlm = data;
417         struct dlm_create_lock *create = (struct dlm_create_lock *)msg->buf;
418         struct dlm_lock_resource *res = NULL;
419         struct dlm_lock *newlock = NULL;
420         struct dlm_lockstatus *lksb = NULL;
421         enum dlm_status status = DLM_NORMAL;
422         char *name;
423         unsigned int namelen;
424
425         BUG_ON(!dlm);
426
427         mlog_entry_void();
428
429         if (!dlm_grab(dlm))
430                 return DLM_REJECTED;
431
432         mlog_bug_on_msg(!dlm_domain_fully_joined(dlm),
433                         "Domain %s not fully joined!\n", dlm->name);
434
435         name = create->name;
436         namelen = create->namelen;
437
438         status = DLM_IVBUFLEN;
439         if (namelen > DLM_LOCKID_NAME_MAX) {
440                 dlm_error(status);
441                 goto leave;
442         }
443
444         status = DLM_SYSERR;
445         newlock = dlm_new_lock(create->requested_type,
446                                create->node_idx,
447                                be64_to_cpu(create->cookie), NULL);
448         if (!newlock) {
449                 dlm_error(status);
450                 goto leave;
451         }
452
453         lksb = newlock->lksb;
454
455         if (be32_to_cpu(create->flags) & LKM_GET_LVB) {
456                 lksb->flags |= DLM_LKSB_GET_LVB;
457                 mlog(0, "set DLM_LKSB_GET_LVB flag\n");
458         }
459
460         status = DLM_IVLOCKID;
461         res = dlm_lookup_lockres(dlm, name, namelen);
462         if (!res) {
463                 dlm_error(status);
464                 goto leave;
465         }
466
467         spin_lock(&res->spinlock);
468         status = __dlm_lockres_state_to_status(res);
469         spin_unlock(&res->spinlock);
470
471         if (status != DLM_NORMAL) {
472                 mlog(0, "lockres recovering/migrating/in-progress\n");
473                 goto leave;
474         }
475
476         dlm_lock_attach_lockres(newlock, res);
477
478         status = dlmlock_master(dlm, res, newlock, be32_to_cpu(create->flags));
479 leave:
480         if (status != DLM_NORMAL)
481                 if (newlock)
482                         dlm_lock_put(newlock);
483
484         if (res)
485                 dlm_lockres_put(res);
486
487         dlm_put(dlm);
488
489         return status;
490 }
491
492
493 /* fetch next node-local (u8 nodenum + u56 cookie) into u64 */
494 static inline void dlm_get_next_cookie(u8 node_num, u64 *cookie)
495 {
496         u64 tmpnode = node_num;
497
498         /* shift single byte of node num into top 8 bits */
499         tmpnode <<= 56;
500
501         spin_lock(&dlm_cookie_lock);
502         *cookie = (dlm_next_cookie | tmpnode);
503         if (++dlm_next_cookie & 0xff00000000000000ull) {
504                 mlog(0, "This node's cookie will now wrap!\n");
505                 dlm_next_cookie = 1;
506         }
507         spin_unlock(&dlm_cookie_lock);
508 }
509
510 enum dlm_status dlmlock(struct dlm_ctxt *dlm, int mode,
511                         struct dlm_lockstatus *lksb, int flags,
512                         const char *name, dlm_astlockfunc_t *ast, void *data,
513                         dlm_bastlockfunc_t *bast)
514 {
515         enum dlm_status status;
516         struct dlm_lock_resource *res = NULL;
517         struct dlm_lock *lock = NULL;
518         int convert = 0, recovery = 0;
519
520         /* yes this function is a mess.
521          * TODO: clean this up.  lots of common code in the
522          *       lock and convert paths, especially in the retry blocks */
523         if (!lksb) {
524                 dlm_error(DLM_BADARGS);
525                 return DLM_BADARGS;
526         }
527
528         status = DLM_BADPARAM;
529         if (mode != LKM_EXMODE && mode != LKM_PRMODE && mode != LKM_NLMODE) {
530                 dlm_error(status);
531                 goto error;
532         }
533
534         if (flags & ~LKM_VALID_FLAGS) {
535                 dlm_error(status);
536                 goto error;
537         }
538
539         convert = (flags & LKM_CONVERT);
540         recovery = (flags & LKM_RECOVERY);
541
542         if (recovery &&
543             (!dlm_is_recovery_lock(name, strlen(name)) || convert) ) {
544                 dlm_error(status);
545                 goto error;
546         }
547         if (convert && (flags & LKM_LOCAL)) {
548                 mlog(ML_ERROR, "strange LOCAL convert request!\n");
549                 goto error;
550         }
551
552         if (convert) {
553                 /* CONVERT request */
554
555                 /* if converting, must pass in a valid dlm_lock */
556                 lock = lksb->lockid;
557                 if (!lock) {
558                         mlog(ML_ERROR, "NULL lock pointer in convert "
559                              "request\n");
560                         goto error;
561                 }
562
563                 res = lock->lockres;
564                 if (!res) {
565                         mlog(ML_ERROR, "NULL lockres pointer in convert "
566                              "request\n");
567                         goto error;
568                 }
569                 dlm_lockres_get(res);
570
571                 /* XXX: for ocfs2 purposes, the ast/bast/astdata/lksb are
572                  * static after the original lock call.  convert requests will
573                  * ensure that everything is the same, or return DLM_BADARGS.
574                  * this means that DLM_DENIED_NOASTS will never be returned.
575                  */
576                 if (lock->lksb != lksb || lock->ast != ast ||
577                     lock->bast != bast || lock->astdata != data) {
578                         status = DLM_BADARGS;
579                         mlog(ML_ERROR, "new args:  lksb=%p, ast=%p, bast=%p, "
580                              "astdata=%p\n", lksb, ast, bast, data);
581                         mlog(ML_ERROR, "orig args: lksb=%p, ast=%p, bast=%p, "
582                              "astdata=%p\n", lock->lksb, lock->ast,
583                              lock->bast, lock->astdata);
584                         goto error;
585                 }
586 retry_convert:
587                 dlm_wait_for_recovery(dlm);
588
589                 if (res->owner == dlm->node_num)
590                         status = dlmconvert_master(dlm, res, lock, flags, mode);
591                 else
592                         status = dlmconvert_remote(dlm, res, lock, flags, mode);
593                 if (status == DLM_RECOVERING || status == DLM_MIGRATING ||
594                     status == DLM_FORWARD) {
595                         /* for now, see how this works without sleeping
596                          * and just retry right away.  I suspect the reco
597                          * or migration will complete fast enough that
598                          * no waiting will be necessary */
599                         mlog(0, "retrying convert with migration/recovery/"
600                              "in-progress\n");
601                         msleep(100);
602                         goto retry_convert;
603                 }
604         } else {
605                 u64 tmpcookie;
606
607                 /* LOCK request */
608                 status = DLM_BADARGS;
609                 if (!name) {
610                         dlm_error(status);
611                         goto error;
612                 }
613
614                 status = DLM_IVBUFLEN;
615                 if (strlen(name) > DLM_LOCKID_NAME_MAX || strlen(name) < 1) {
616                         dlm_error(status);
617                         goto error;
618                 }
619
620                 dlm_get_next_cookie(dlm->node_num, &tmpcookie);
621                 lock = dlm_new_lock(mode, dlm->node_num, tmpcookie, lksb);
622                 if (!lock) {
623                         dlm_error(status);
624                         goto error;
625                 }
626
627                 if (!recovery)
628                         dlm_wait_for_recovery(dlm);
629
630                 /* find or create the lock resource */
631                 res = dlm_get_lock_resource(dlm, name, flags);
632                 if (!res) {
633                         status = DLM_IVLOCKID;
634                         dlm_error(status);
635                         goto error;
636                 }
637
638                 mlog(0, "type=%d, flags = 0x%x\n", mode, flags);
639                 mlog(0, "creating lock: lock=%p res=%p\n", lock, res);
640
641                 dlm_lock_attach_lockres(lock, res);
642                 lock->ast = ast;
643                 lock->bast = bast;
644                 lock->astdata = data;
645
646 retry_lock:
647                 if (flags & LKM_VALBLK) {
648                         mlog(0, "LKM_VALBLK passed by caller\n");
649
650                         /* LVB requests for non PR, PW or EX locks are
651                          * ignored. */
652                         if (mode < LKM_PRMODE)
653                                 flags &= ~LKM_VALBLK;
654                         else {
655                                 flags |= LKM_GET_LVB;
656                                 lock->lksb->flags |= DLM_LKSB_GET_LVB;
657                         }
658                 }
659
660                 if (res->owner == dlm->node_num)
661                         status = dlmlock_master(dlm, res, lock, flags);
662                 else
663                         status = dlmlock_remote(dlm, res, lock, flags);
664
665                 if (status == DLM_RECOVERING || status == DLM_MIGRATING ||
666                     status == DLM_FORWARD) {
667                         mlog(0, "retrying lock with migration/"
668                              "recovery/in progress\n");
669                         msleep(100);
670                         /* no waiting for dlm_reco_thread */
671                         if (recovery) {
672                                 if (status == DLM_RECOVERING) {
673                                         mlog(0, "%s: got RECOVERING "
674                                              "for $REOCVERY lock, master "
675                                              "was %u\n", dlm->name, 
676                                              res->owner);
677                                         dlm_wait_for_node_death(dlm, res->owner, 
678                                                         DLM_NODE_DEATH_WAIT_MAX);
679                                 }
680                         } else {
681                                 dlm_wait_for_recovery(dlm);
682                         }
683                         goto retry_lock;
684                 }
685
686                 if (status != DLM_NORMAL) {
687                         lock->lksb->flags &= ~DLM_LKSB_GET_LVB;
688                         if (status != DLM_NOTQUEUED)
689                                 dlm_error(status);
690                         goto error;
691                 }
692         }
693
694 error:
695         if (status != DLM_NORMAL) {
696                 if (lock && !convert)
697                         dlm_lock_put(lock);
698                 // this is kind of unnecessary
699                 lksb->status = status;
700         }
701
702         /* put lockres ref from the convert path
703          * or from dlm_get_lock_resource */
704         if (res)
705                 dlm_lockres_put(res);
706
707         return status;
708 }
709 EXPORT_SYMBOL_GPL(dlmlock);