1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * dlmlock.c
4 *
5 * underlying calls for lock creation
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/slab.h>
15#include <linux/highmem.h>
16#include <linux/init.h>
17#include <linux/sysctl.h>
18#include <linux/random.h>
19#include <linux/blkdev.h>
20#include <linux/socket.h>
21#include <linux/inet.h>
22#include <linux/spinlock.h>
23#include <linux/delay.h>
24
25
26#include "../cluster/heartbeat.h"
27#include "../cluster/nodemanager.h"
28#include "../cluster/tcp.h"
29
30#include "dlmapi.h"
31#include "dlmcommon.h"
32
33#include "dlmconvert.h"
34
35#define MLOG_MASK_PREFIX ML_DLM
36#include "../cluster/masklog.h"
37
38static struct kmem_cache *dlm_lock_cache;
39
40static DEFINE_SPINLOCK(dlm_cookie_lock);
41static u64 dlm_next_cookie = 1;
42
43static enum dlm_status dlm_send_remote_lock_request(struct dlm_ctxt *dlm,
44 struct dlm_lock_resource *res,
45 struct dlm_lock *lock, int flags);
46static void dlm_init_lock(struct dlm_lock *newlock, int type,
47 u8 node, u64 cookie);
48static void dlm_lock_release(struct kref *kref);
49static void dlm_lock_detach_lockres(struct dlm_lock *lock);
50
51int dlm_init_lock_cache(void)
52{
53 dlm_lock_cache = kmem_cache_create(name: "o2dlm_lock",
54 size: sizeof(struct dlm_lock),
55 align: 0, SLAB_HWCACHE_ALIGN, NULL);
56 if (dlm_lock_cache == NULL)
57 return -ENOMEM;
58 return 0;
59}
60
61void dlm_destroy_lock_cache(void)
62{
63 kmem_cache_destroy(s: dlm_lock_cache);
64}
65
66/* Tell us whether we can grant a new lock request.
67 * locking:
68 * caller needs: res->spinlock
69 * taken: none
70 * held on exit: none
71 * returns: 1 if the lock can be granted, 0 otherwise.
72 */
73static int dlm_can_grant_new_lock(struct dlm_lock_resource *res,
74 struct dlm_lock *lock)
75{
76 struct dlm_lock *tmplock;
77
78 list_for_each_entry(tmplock, &res->granted, list) {
79 if (!dlm_lock_compatible(existing: tmplock->ml.type, request: lock->ml.type))
80 return 0;
81 }
82
83 list_for_each_entry(tmplock, &res->converting, list) {
84 if (!dlm_lock_compatible(existing: tmplock->ml.type, request: lock->ml.type))
85 return 0;
86 if (!dlm_lock_compatible(existing: tmplock->ml.convert_type,
87 request: lock->ml.type))
88 return 0;
89 }
90
91 return 1;
92}
93
94/* performs lock creation at the lockres master site
95 * locking:
96 * caller needs: none
97 * taken: takes and drops res->spinlock
98 * held on exit: none
99 * returns: DLM_NORMAL, DLM_NOTQUEUED
100 */
101static enum dlm_status dlmlock_master(struct dlm_ctxt *dlm,
102 struct dlm_lock_resource *res,
103 struct dlm_lock *lock, int flags)
104{
105 int call_ast = 0, kick_thread = 0;
106 enum dlm_status status = DLM_NORMAL;
107
108 mlog(0, "type=%d\n", lock->ml.type);
109
110 spin_lock(lock: &res->spinlock);
111 /* if called from dlm_create_lock_handler, need to
112 * ensure it will not sleep in dlm_wait_on_lockres */
113 status = __dlm_lockres_state_to_status(res);
114 if (status != DLM_NORMAL &&
115 lock->ml.node != dlm->node_num) {
116 /* erf. state changed after lock was dropped. */
117 spin_unlock(lock: &res->spinlock);
118 dlm_error(status);
119 return status;
120 }
121 __dlm_wait_on_lockres(res);
122 __dlm_lockres_reserve_ast(res);
123
124 if (dlm_can_grant_new_lock(res, lock)) {
125 mlog(0, "I can grant this lock right away\n");
126 /* got it right away */
127 lock->lksb->status = DLM_NORMAL;
128 status = DLM_NORMAL;
129 dlm_lock_get(lock);
130 list_add_tail(new: &lock->list, head: &res->granted);
131
132 /* for the recovery lock, we can't allow the ast
133 * to be queued since the dlmthread is already
134 * frozen. but the recovery lock is always locked
135 * with LKM_NOQUEUE so we do not need the ast in
136 * this special case */
137 if (!dlm_is_recovery_lock(lock_name: res->lockname.name,
138 name_len: res->lockname.len)) {
139 kick_thread = 1;
140 call_ast = 1;
141 } else {
142 mlog(0, "%s: returning DLM_NORMAL to "
143 "node %u for reco lock\n", dlm->name,
144 lock->ml.node);
145 }
146 } else {
147 /* for NOQUEUE request, unless we get the
148 * lock right away, return DLM_NOTQUEUED */
149 if (flags & LKM_NOQUEUE) {
150 status = DLM_NOTQUEUED;
151 if (dlm_is_recovery_lock(lock_name: res->lockname.name,
152 name_len: res->lockname.len)) {
153 mlog(0, "%s: returning NOTQUEUED to "
154 "node %u for reco lock\n", dlm->name,
155 lock->ml.node);
156 }
157 } else {
158 status = DLM_NORMAL;
159 dlm_lock_get(lock);
160 list_add_tail(new: &lock->list, head: &res->blocked);
161 kick_thread = 1;
162 }
163 }
164
165 spin_unlock(lock: &res->spinlock);
166 wake_up(&res->wq);
167
168 /* either queue the ast or release it */
169 if (call_ast)
170 dlm_queue_ast(dlm, lock);
171 else
172 dlm_lockres_release_ast(dlm, res);
173
174 dlm_lockres_calc_usage(dlm, res);
175 if (kick_thread)
176 dlm_kick_thread(dlm, res);
177
178 return status;
179}
180
181void dlm_revert_pending_lock(struct dlm_lock_resource *res,
182 struct dlm_lock *lock)
183{
184 /* remove from local queue if it failed */
185 list_del_init(entry: &lock->list);
186 lock->lksb->flags &= ~DLM_LKSB_GET_LVB;
187}
188
189
190/*
191 * locking:
192 * caller needs: none
193 * taken: takes and drops res->spinlock
194 * held on exit: none
195 * returns: DLM_DENIED, DLM_RECOVERING, or net status
196 */
197static enum dlm_status dlmlock_remote(struct dlm_ctxt *dlm,
198 struct dlm_lock_resource *res,
199 struct dlm_lock *lock, int flags)
200{
201 enum dlm_status status = DLM_DENIED;
202 int lockres_changed = 1;
203
204 mlog(0, "type=%d, lockres %.*s, flags = 0x%x\n",
205 lock->ml.type, res->lockname.len,
206 res->lockname.name, flags);
207
208 /*
209 * Wait if resource is getting recovered, remastered, etc.
210 * If the resource was remastered and new owner is self, then exit.
211 */
212 spin_lock(lock: &res->spinlock);
213 __dlm_wait_on_lockres(res);
214 if (res->owner == dlm->node_num) {
215 spin_unlock(lock: &res->spinlock);
216 return DLM_RECOVERING;
217 }
218 res->state |= DLM_LOCK_RES_IN_PROGRESS;
219
220 /* add lock to local (secondary) queue */
221 dlm_lock_get(lock);
222 list_add_tail(new: &lock->list, head: &res->blocked);
223 lock->lock_pending = 1;
224 spin_unlock(lock: &res->spinlock);
225
226 /* spec seems to say that you will get DLM_NORMAL when the lock
227 * has been queued, meaning we need to wait for a reply here. */
228 status = dlm_send_remote_lock_request(dlm, res, lock, flags);
229
230 spin_lock(lock: &res->spinlock);
231 res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
232 lock->lock_pending = 0;
233 if (status != DLM_NORMAL) {
234 if (status == DLM_RECOVERING &&
235 dlm_is_recovery_lock(lock_name: res->lockname.name,
236 name_len: res->lockname.len)) {
237 /* recovery lock was mastered by dead node.
238 * we need to have calc_usage shoot down this
239 * lockres and completely remaster it. */
240 mlog(0, "%s: recovery lock was owned by "
241 "dead node %u, remaster it now.\n",
242 dlm->name, res->owner);
243 } else if (status != DLM_NOTQUEUED) {
244 /*
245 * DO NOT call calc_usage, as this would unhash
246 * the remote lockres before we ever get to use
247 * it. treat as if we never made any change to
248 * the lockres.
249 */
250 lockres_changed = 0;
251 dlm_error(status);
252 }
253 dlm_revert_pending_lock(res, lock);
254 dlm_lock_put(lock);
255 } else if (dlm_is_recovery_lock(lock_name: res->lockname.name,
256 name_len: res->lockname.len)) {
257 /* special case for the $RECOVERY lock.
258 * there will never be an AST delivered to put
259 * this lock on the proper secondary queue
260 * (granted), so do it manually. */
261 mlog(0, "%s: $RECOVERY lock for this node (%u) is "
262 "mastered by %u; got lock, manually granting (no ast)\n",
263 dlm->name, dlm->node_num, res->owner);
264 list_move_tail(list: &lock->list, head: &res->granted);
265 }
266 spin_unlock(lock: &res->spinlock);
267
268 if (lockres_changed)
269 dlm_lockres_calc_usage(dlm, res);
270
271 wake_up(&res->wq);
272 return status;
273}
274
275
276/* for remote lock creation.
277 * locking:
278 * caller needs: none, but need res->state & DLM_LOCK_RES_IN_PROGRESS
279 * taken: none
280 * held on exit: none
281 * returns: DLM_NOLOCKMGR, or net status
282 */
283static enum dlm_status dlm_send_remote_lock_request(struct dlm_ctxt *dlm,
284 struct dlm_lock_resource *res,
285 struct dlm_lock *lock, int flags)
286{
287 struct dlm_create_lock create;
288 int tmpret, status = 0;
289 enum dlm_status ret;
290
291 memset(&create, 0, sizeof(create));
292 create.node_idx = dlm->node_num;
293 create.requested_type = lock->ml.type;
294 create.cookie = lock->ml.cookie;
295 create.namelen = res->lockname.len;
296 create.flags = cpu_to_be32(flags);
297 memcpy(create.name, res->lockname.name, create.namelen);
298
299 tmpret = o2net_send_message(msg_type: DLM_CREATE_LOCK_MSG, key: dlm->key, data: &create,
300 len: sizeof(create), target_node: res->owner, status: &status);
301 if (tmpret >= 0) {
302 ret = status;
303 if (ret == DLM_REJECTED) {
304 mlog(ML_ERROR, "%s: res %.*s, Stale lockres no longer "
305 "owned by node %u. That node is coming back up "
306 "currently.\n", dlm->name, create.namelen,
307 create.name, res->owner);
308 dlm_print_one_lock_resource(res);
309 BUG();
310 }
311 } else {
312 mlog(ML_ERROR, "%s: res %.*s, Error %d send CREATE LOCK to "
313 "node %u\n", dlm->name, create.namelen, create.name,
314 tmpret, res->owner);
315 if (dlm_is_host_down(errno: tmpret))
316 ret = DLM_RECOVERING;
317 else
318 ret = dlm_err_to_dlm_status(err: tmpret);
319 }
320
321 return ret;
322}
323
324void dlm_lock_get(struct dlm_lock *lock)
325{
326 kref_get(kref: &lock->lock_refs);
327}
328
329void dlm_lock_put(struct dlm_lock *lock)
330{
331 kref_put(kref: &lock->lock_refs, release: dlm_lock_release);
332}
333
334static void dlm_lock_release(struct kref *kref)
335{
336 struct dlm_lock *lock;
337
338 lock = container_of(kref, struct dlm_lock, lock_refs);
339
340 BUG_ON(!list_empty(&lock->list));
341 BUG_ON(!list_empty(&lock->ast_list));
342 BUG_ON(!list_empty(&lock->bast_list));
343 BUG_ON(lock->ast_pending);
344 BUG_ON(lock->bast_pending);
345
346 dlm_lock_detach_lockres(lock);
347
348 if (lock->lksb_kernel_allocated) {
349 mlog(0, "freeing kernel-allocated lksb\n");
350 kfree(objp: lock->lksb);
351 }
352 kmem_cache_free(s: dlm_lock_cache, objp: lock);
353}
354
355/* associate a lock with it's lockres, getting a ref on the lockres */
356void dlm_lock_attach_lockres(struct dlm_lock *lock,
357 struct dlm_lock_resource *res)
358{
359 dlm_lockres_get(res);
360 lock->lockres = res;
361}
362
363/* drop ref on lockres, if there is still one associated with lock */
364static void dlm_lock_detach_lockres(struct dlm_lock *lock)
365{
366 struct dlm_lock_resource *res;
367
368 res = lock->lockres;
369 if (res) {
370 lock->lockres = NULL;
371 mlog(0, "removing lock's lockres reference\n");
372 dlm_lockres_put(res);
373 }
374}
375
376static void dlm_init_lock(struct dlm_lock *newlock, int type,
377 u8 node, u64 cookie)
378{
379 INIT_LIST_HEAD(list: &newlock->list);
380 INIT_LIST_HEAD(list: &newlock->ast_list);
381 INIT_LIST_HEAD(list: &newlock->bast_list);
382 spin_lock_init(&newlock->spinlock);
383 newlock->ml.type = type;
384 newlock->ml.convert_type = LKM_IVMODE;
385 newlock->ml.highest_blocked = LKM_IVMODE;
386 newlock->ml.node = node;
387 newlock->ml.pad1 = 0;
388 newlock->ml.list = 0;
389 newlock->ml.flags = 0;
390 newlock->ast = NULL;
391 newlock->bast = NULL;
392 newlock->astdata = NULL;
393 newlock->ml.cookie = cpu_to_be64(cookie);
394 newlock->ast_pending = 0;
395 newlock->bast_pending = 0;
396 newlock->convert_pending = 0;
397 newlock->lock_pending = 0;
398 newlock->unlock_pending = 0;
399 newlock->cancel_pending = 0;
400 newlock->lksb_kernel_allocated = 0;
401
402 kref_init(kref: &newlock->lock_refs);
403}
404
405struct dlm_lock * dlm_new_lock(int type, u8 node, u64 cookie,
406 struct dlm_lockstatus *lksb)
407{
408 struct dlm_lock *lock;
409 int kernel_allocated = 0;
410
411 lock = kmem_cache_zalloc(k: dlm_lock_cache, GFP_NOFS);
412 if (!lock)
413 return NULL;
414
415 if (!lksb) {
416 /* zero memory only if kernel-allocated */
417 lksb = kzalloc(size: sizeof(*lksb), GFP_NOFS);
418 if (!lksb) {
419 kmem_cache_free(s: dlm_lock_cache, objp: lock);
420 return NULL;
421 }
422 kernel_allocated = 1;
423 }
424
425 dlm_init_lock(newlock: lock, type, node, cookie);
426 if (kernel_allocated)
427 lock->lksb_kernel_allocated = 1;
428 lock->lksb = lksb;
429 lksb->lockid = lock;
430 return lock;
431}
432
433/* handler for lock creation net message
434 * locking:
435 * caller needs: none
436 * taken: takes and drops res->spinlock
437 * held on exit: none
438 * returns: DLM_NORMAL, DLM_SYSERR, DLM_IVLOCKID, DLM_NOTQUEUED
439 */
440int dlm_create_lock_handler(struct o2net_msg *msg, u32 len, void *data,
441 void **ret_data)
442{
443 struct dlm_ctxt *dlm = data;
444 struct dlm_create_lock *create = (struct dlm_create_lock *)msg->buf;
445 struct dlm_lock_resource *res = NULL;
446 struct dlm_lock *newlock = NULL;
447 struct dlm_lockstatus *lksb = NULL;
448 enum dlm_status status = DLM_NORMAL;
449 char *name;
450 unsigned int namelen;
451
452 BUG_ON(!dlm);
453
454 if (!dlm_grab(dlm))
455 return DLM_REJECTED;
456
457 name = create->name;
458 namelen = create->namelen;
459 status = DLM_REJECTED;
460 if (!dlm_domain_fully_joined(dlm)) {
461 mlog(ML_ERROR, "Domain %s not fully joined, but node %u is "
462 "sending a create_lock message for lock %.*s!\n",
463 dlm->name, create->node_idx, namelen, name);
464 dlm_error(status);
465 goto leave;
466 }
467
468 status = DLM_IVBUFLEN;
469 if (namelen > DLM_LOCKID_NAME_MAX) {
470 dlm_error(status);
471 goto leave;
472 }
473
474 status = DLM_SYSERR;
475 newlock = dlm_new_lock(type: create->requested_type,
476 node: create->node_idx,
477 be64_to_cpu(create->cookie), NULL);
478 if (!newlock) {
479 dlm_error(status);
480 goto leave;
481 }
482
483 lksb = newlock->lksb;
484
485 if (be32_to_cpu(create->flags) & LKM_GET_LVB) {
486 lksb->flags |= DLM_LKSB_GET_LVB;
487 mlog(0, "set DLM_LKSB_GET_LVB flag\n");
488 }
489
490 status = DLM_IVLOCKID;
491 res = dlm_lookup_lockres(dlm, name, len: namelen);
492 if (!res) {
493 dlm_error(status);
494 goto leave;
495 }
496
497 spin_lock(lock: &res->spinlock);
498 status = __dlm_lockres_state_to_status(res);
499 spin_unlock(lock: &res->spinlock);
500
501 if (status != DLM_NORMAL) {
502 mlog(0, "lockres recovering/migrating/in-progress\n");
503 goto leave;
504 }
505
506 dlm_lock_attach_lockres(lock: newlock, res);
507
508 status = dlmlock_master(dlm, res, lock: newlock, be32_to_cpu(create->flags));
509leave:
510 if (status != DLM_NORMAL)
511 if (newlock)
512 dlm_lock_put(lock: newlock);
513
514 if (res)
515 dlm_lockres_put(res);
516
517 dlm_put(dlm);
518
519 return status;
520}
521
522
523/* fetch next node-local (u8 nodenum + u56 cookie) into u64 */
524static inline void dlm_get_next_cookie(u8 node_num, u64 *cookie)
525{
526 u64 tmpnode = node_num;
527
528 /* shift single byte of node num into top 8 bits */
529 tmpnode <<= 56;
530
531 spin_lock(lock: &dlm_cookie_lock);
532 *cookie = (dlm_next_cookie | tmpnode);
533 if (++dlm_next_cookie & 0xff00000000000000ull) {
534 mlog(0, "This node's cookie will now wrap!\n");
535 dlm_next_cookie = 1;
536 }
537 spin_unlock(lock: &dlm_cookie_lock);
538}
539
540enum dlm_status dlmlock(struct dlm_ctxt *dlm, int mode,
541 struct dlm_lockstatus *lksb, int flags,
542 const char *name, int namelen, dlm_astlockfunc_t *ast,
543 void *data, dlm_bastlockfunc_t *bast)
544{
545 enum dlm_status status;
546 struct dlm_lock_resource *res = NULL;
547 struct dlm_lock *lock = NULL;
548 int convert = 0, recovery = 0;
549
550 /* yes this function is a mess.
551 * TODO: clean this up. lots of common code in the
552 * lock and convert paths, especially in the retry blocks */
553 if (!lksb) {
554 dlm_error(DLM_BADARGS);
555 return DLM_BADARGS;
556 }
557
558 status = DLM_BADPARAM;
559 if (mode != LKM_EXMODE && mode != LKM_PRMODE && mode != LKM_NLMODE) {
560 dlm_error(status);
561 goto error;
562 }
563
564 if (flags & ~LKM_VALID_FLAGS) {
565 dlm_error(status);
566 goto error;
567 }
568
569 convert = (flags & LKM_CONVERT);
570 recovery = (flags & LKM_RECOVERY);
571
572 if (recovery &&
573 (!dlm_is_recovery_lock(lock_name: name, name_len: namelen) || convert) ) {
574 dlm_error(status);
575 goto error;
576 }
577 if (convert && (flags & LKM_LOCAL)) {
578 mlog(ML_ERROR, "strange LOCAL convert request!\n");
579 goto error;
580 }
581
582 if (convert) {
583 /* CONVERT request */
584
585 /* if converting, must pass in a valid dlm_lock */
586 lock = lksb->lockid;
587 if (!lock) {
588 mlog(ML_ERROR, "NULL lock pointer in convert "
589 "request\n");
590 goto error;
591 }
592
593 res = lock->lockres;
594 if (!res) {
595 mlog(ML_ERROR, "NULL lockres pointer in convert "
596 "request\n");
597 goto error;
598 }
599 dlm_lockres_get(res);
600
601 /* XXX: for ocfs2 purposes, the ast/bast/astdata/lksb are
602 * static after the original lock call. convert requests will
603 * ensure that everything is the same, or return DLM_BADARGS.
604 * this means that DLM_DENIED_NOASTS will never be returned.
605 */
606 if (lock->lksb != lksb || lock->ast != ast ||
607 lock->bast != bast || lock->astdata != data) {
608 status = DLM_BADARGS;
609 mlog(ML_ERROR, "new args: lksb=%p, ast=%p, bast=%p, "
610 "astdata=%p\n", lksb, ast, bast, data);
611 mlog(ML_ERROR, "orig args: lksb=%p, ast=%p, bast=%p, "
612 "astdata=%p\n", lock->lksb, lock->ast,
613 lock->bast, lock->astdata);
614 goto error;
615 }
616retry_convert:
617 dlm_wait_for_recovery(dlm);
618
619 if (res->owner == dlm->node_num)
620 status = dlmconvert_master(dlm, res, lock, flags, type: mode);
621 else
622 status = dlmconvert_remote(dlm, res, lock, flags, type: mode);
623 if (status == DLM_RECOVERING || status == DLM_MIGRATING ||
624 status == DLM_FORWARD) {
625 /* for now, see how this works without sleeping
626 * and just retry right away. I suspect the reco
627 * or migration will complete fast enough that
628 * no waiting will be necessary */
629 mlog(0, "retrying convert with migration/recovery/"
630 "in-progress\n");
631 msleep(msecs: 100);
632 goto retry_convert;
633 }
634 } else {
635 u64 tmpcookie;
636
637 /* LOCK request */
638 status = DLM_BADARGS;
639 if (!name) {
640 dlm_error(status);
641 goto error;
642 }
643
644 status = DLM_IVBUFLEN;
645 if (namelen > DLM_LOCKID_NAME_MAX || namelen < 1) {
646 dlm_error(status);
647 goto error;
648 }
649
650 dlm_get_next_cookie(node_num: dlm->node_num, cookie: &tmpcookie);
651 lock = dlm_new_lock(type: mode, node: dlm->node_num, cookie: tmpcookie, lksb);
652 if (!lock) {
653 dlm_error(status);
654 goto error;
655 }
656
657 if (!recovery)
658 dlm_wait_for_recovery(dlm);
659
660 /* find or create the lock resource */
661 res = dlm_get_lock_resource(dlm, lockid: name, namelen, flags);
662 if (!res) {
663 status = DLM_IVLOCKID;
664 dlm_error(status);
665 goto error;
666 }
667
668 mlog(0, "type=%d, flags = 0x%x\n", mode, flags);
669 mlog(0, "creating lock: lock=%p res=%p\n", lock, res);
670
671 dlm_lock_attach_lockres(lock, res);
672 lock->ast = ast;
673 lock->bast = bast;
674 lock->astdata = data;
675
676retry_lock:
677 if (flags & LKM_VALBLK) {
678 mlog(0, "LKM_VALBLK passed by caller\n");
679
680 /* LVB requests for non PR, PW or EX locks are
681 * ignored. */
682 if (mode < LKM_PRMODE)
683 flags &= ~LKM_VALBLK;
684 else {
685 flags |= LKM_GET_LVB;
686 lock->lksb->flags |= DLM_LKSB_GET_LVB;
687 }
688 }
689
690 if (res->owner == dlm->node_num)
691 status = dlmlock_master(dlm, res, lock, flags);
692 else
693 status = dlmlock_remote(dlm, res, lock, flags);
694
695 if (status == DLM_RECOVERING || status == DLM_MIGRATING ||
696 status == DLM_FORWARD) {
697 msleep(msecs: 100);
698 if (recovery) {
699 if (status != DLM_RECOVERING)
700 goto retry_lock;
701 /* wait to see the node go down, then
702 * drop down and allow the lockres to
703 * get cleaned up. need to remaster. */
704 dlm_wait_for_node_death(dlm, node: res->owner,
705 DLM_NODE_DEATH_WAIT_MAX);
706 } else {
707 dlm_wait_for_recovery(dlm);
708 goto retry_lock;
709 }
710 }
711
712 /* Inflight taken in dlm_get_lock_resource() is dropped here */
713 spin_lock(lock: &res->spinlock);
714 dlm_lockres_drop_inflight_ref(dlm, res);
715 spin_unlock(lock: &res->spinlock);
716
717 dlm_lockres_calc_usage(dlm, res);
718 dlm_kick_thread(dlm, res);
719
720 if (status != DLM_NORMAL) {
721 lock->lksb->flags &= ~DLM_LKSB_GET_LVB;
722 if (status != DLM_NOTQUEUED)
723 dlm_error(status);
724 goto error;
725 }
726 }
727
728error:
729 if (status != DLM_NORMAL) {
730 if (lock && !convert)
731 dlm_lock_put(lock);
732 // this is kind of unnecessary
733 lksb->status = status;
734 }
735
736 /* put lockres ref from the convert path
737 * or from dlm_get_lock_resource */
738 if (res)
739 dlm_lockres_put(res);
740
741 return status;
742}
743EXPORT_SYMBOL_GPL(dlmlock);
744

source code of linux/fs/ocfs2/dlm/dlmlock.c