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

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  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/init.h>
 34 #include <linux/sysctl.h>
 35 #include <linux/random.h>
 36 #include <linux/blkdev.h>
 37 #include <linux/socket.h>
 38 #include <linux/inet.h>
 39 #include <linux/spinlock.h>
 40 #include <linux/delay.h>
 41 
 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 #include "dlmconvert.h"
 51 
 52 #define MLOG_MASK_PREFIX ML_DLM
 53 #include "cluster/masklog.h"
 54 
 55 static struct kmem_cache *dlm_lock_cache;
 56 
 57 static DEFINE_SPINLOCK(dlm_cookie_lock);
 58 static u64 dlm_next_cookie = 1;
 59 
 60 static enum dlm_status dlm_send_remote_lock_request(struct dlm_ctxt *dlm,
 61                                                struct dlm_lock_resource *res,
 62                                                struct dlm_lock *lock, int flags);
 63 static void dlm_init_lock(struct dlm_lock *newlock, int type,
 64                           u8 node, u64 cookie);
 65 static void dlm_lock_release(struct kref *kref);
 66 static void dlm_lock_detach_lockres(struct dlm_lock *lock);
 67 
 68 int dlm_init_lock_cache(void)
 69 {
 70         dlm_lock_cache = kmem_cache_create("o2dlm_lock",
 71                                            sizeof(struct dlm_lock),
 72                                            0, SLAB_HWCACHE_ALIGN, NULL);
 73         if (dlm_lock_cache == NULL)
 74                 return -ENOMEM;
 75         return 0;
 76 }
 77 
 78 void dlm_destroy_lock_cache(void)
 79 {
 80         kmem_cache_destroy(dlm_lock_cache);
 81 }
 82 
 83 /* Tell us whether we can grant a new lock request.
 84  * locking:
 85  *   caller needs:  res->spinlock
 86  *   taken:         none
 87  *   held on exit:  none
 88  * returns: 1 if the lock can be granted, 0 otherwise.
 89  */
 90 static int dlm_can_grant_new_lock(struct dlm_lock_resource *res,
 91                                   struct dlm_lock *lock)
 92 {
 93         struct dlm_lock *tmplock;
 94 
 95         list_for_each_entry(tmplock, &res->granted, list) {
 96                 if (!dlm_lock_compatible(tmplock->ml.type, lock->ml.type))
 97                         return 0;
 98         }
 99 
100         list_for_each_entry(tmplock, &res->converting, list) {
101                 if (!dlm_lock_compatible(tmplock->ml.type, lock->ml.type))
102                         return 0;
103                 if (!dlm_lock_compatible(tmplock->ml.convert_type,
104                                          lock->ml.type))
105                         return 0;
106         }
107 
108         return 1;
109 }
110 
111 /* performs lock creation at the lockres master site
112  * locking:
113  *   caller needs:  none
114  *   taken:         takes and drops res->spinlock
115  *   held on exit:  none
116  * returns: DLM_NORMAL, DLM_NOTQUEUED
117  */
118 static enum dlm_status dlmlock_master(struct dlm_ctxt *dlm,
119                                       struct dlm_lock_resource *res,
120                                       struct dlm_lock *lock, int flags)
121 {
122         int call_ast = 0, kick_thread = 0;
123         enum dlm_status status = DLM_NORMAL;
124 
125         mlog(0, "type=%d\n", lock->ml.type);
126 
127         spin_lock(&res->spinlock);
128         /* if called from dlm_create_lock_handler, need to
129          * ensure it will not sleep in dlm_wait_on_lockres */
130         status = __dlm_lockres_state_to_status(res);
131         if (status != DLM_NORMAL &&
132             lock->ml.node != dlm->node_num) {
133                 /* erf.  state changed after lock was dropped. */
134                 spin_unlock(&res->spinlock);
135                 dlm_error(status);
136                 return status;
137         }
138         __dlm_wait_on_lockres(res);
139         __dlm_lockres_reserve_ast(res);
140 
141         if (dlm_can_grant_new_lock(res, lock)) {
142                 mlog(0, "I can grant this lock right away\n");
143                 /* got it right away */
144                 lock->lksb->status = DLM_NORMAL;
145                 status = DLM_NORMAL;
146                 dlm_lock_get(lock);
147                 list_add_tail(&lock->list, &res->granted);
148 
149                 /* for the recovery lock, we can't allow the ast
150                  * to be queued since the dlmthread is already
151                  * frozen.  but the recovery lock is always locked
152                  * with LKM_NOQUEUE so we do not need the ast in
153                  * this special case */
154                 if (!dlm_is_recovery_lock(res->lockname.name,
155                                           res->lockname.len)) {
156                         kick_thread = 1;
157                         call_ast = 1;
158                 } else {
159                         mlog(0, "%s: returning DLM_NORMAL to "
160                              "node %u for reco lock\n", dlm->name,
161                              lock->ml.node);
162                 }
163         } else {
164                 /* for NOQUEUE request, unless we get the
165                  * lock right away, return DLM_NOTQUEUED */
166                 if (flags & LKM_NOQUEUE) {
167                         status = DLM_NOTQUEUED;
168                         if (dlm_is_recovery_lock(res->lockname.name,
169                                                  res->lockname.len)) {
170                                 mlog(0, "%s: returning NOTQUEUED to "
171                                      "node %u for reco lock\n", dlm->name,
172                                      lock->ml.node);
173                         }
174                 } else {
175                         status = DLM_NORMAL;
176                         dlm_lock_get(lock);
177                         list_add_tail(&lock->list, &res->blocked);
178                         kick_thread = 1;
179                 }
180         }
181 
182         spin_unlock(&res->spinlock);
183         wake_up(&res->wq);
184 
185         /* either queue the ast or release it */
186         if (call_ast)
187                 dlm_queue_ast(dlm, lock);
188         else
189                 dlm_lockres_release_ast(dlm, res);
190 
191         dlm_lockres_calc_usage(dlm, res);
192         if (kick_thread)
193                 dlm_kick_thread(dlm, res);
194 
195         return status;
196 }
197 
198 void dlm_revert_pending_lock(struct dlm_lock_resource *res,
199                              struct dlm_lock *lock)
200 {
201         /* remove from local queue if it failed */
202         list_del_init(&lock->list);
203         lock->lksb->flags &= ~DLM_LKSB_GET_LVB;
204 }
205 
206 
207 /*
208  * locking:
209  *   caller needs:  none
210  *   taken:         takes and drops res->spinlock
211  *   held on exit:  none
212  * returns: DLM_DENIED, DLM_RECOVERING, or net status
213  */
214 static enum dlm_status dlmlock_remote(struct dlm_ctxt *dlm,
215                                       struct dlm_lock_resource *res,
216                                       struct dlm_lock *lock, int flags)
217 {
218         enum dlm_status status = DLM_DENIED;
219         int lockres_changed = 1;
220 
221         mlog(0, "type=%d, lockres %.*s, flags = 0x%x\n",
222              lock->ml.type, res->lockname.len,
223              res->lockname.name, flags);
224 
225         /*
226          * Wait if resource is getting recovered, remastered, etc.
227          * If the resource was remastered and new owner is self, then exit.
228          */
229         spin_lock(&res->spinlock);
230         __dlm_wait_on_lockres(res);
231         if (res->owner == dlm->node_num) {
232                 spin_unlock(&res->spinlock);
233                 return DLM_RECOVERING;
234         }
235         res->state |= DLM_LOCK_RES_IN_PROGRESS;
236 
237         /* add lock to local (secondary) queue */
238         dlm_lock_get(lock);
239         list_add_tail(&lock->list, &res->blocked);
240         lock->lock_pending = 1;
241         spin_unlock(&res->spinlock);
242 
243         /* spec seems to say that you will get DLM_NORMAL when the lock
244          * has been queued, meaning we need to wait for a reply here. */
245         status = dlm_send_remote_lock_request(dlm, res, lock, flags);
246 
247         spin_lock(&res->spinlock);
248         res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
249         lock->lock_pending = 0;
250         if (status != DLM_NORMAL) {
251                 if (status == DLM_RECOVERING &&
252                     dlm_is_recovery_lock(res->lockname.name,
253                                          res->lockname.len)) {
254                         /* recovery lock was mastered by dead node.
255                          * we need to have calc_usage shoot down this
256                          * lockres and completely remaster it. */
257                         mlog(0, "%s: recovery lock was owned by "
258                              "dead node %u, remaster it now.\n",
259                              dlm->name, res->owner);
260                 } else if (status != DLM_NOTQUEUED) {
261                         /*
262                          * DO NOT call calc_usage, as this would unhash
263                          * the remote lockres before we ever get to use
264                          * it.  treat as if we never made any change to
265                          * the lockres.
266                          */
267                         lockres_changed = 0;
268                         dlm_error(status);
269                 }
270                 dlm_revert_pending_lock(res, lock);
271                 dlm_lock_put(lock);
272         } else if (dlm_is_recovery_lock(res->lockname.name,
273                                         res->lockname.len)) {
274                 /* special case for the $RECOVERY lock.
275                  * there will never be an AST delivered to put
276                  * this lock on the proper secondary queue
277                  * (granted), so do it manually. */
278                 mlog(0, "%s: $RECOVERY lock for this node (%u) is "
279                      "mastered by %u; got lock, manually granting (no ast)\n",
280                      dlm->name, dlm->node_num, res->owner);
281                 list_move_tail(&lock->list, &res->granted);
282         }
283         spin_unlock(&res->spinlock);
284 
285         if (lockres_changed)
286                 dlm_lockres_calc_usage(dlm, res);
287 
288         wake_up(&res->wq);
289         return status;
290 }
291 
292 
293 /* for remote lock creation.
294  * locking:
295  *   caller needs:  none, but need res->state & DLM_LOCK_RES_IN_PROGRESS
296  *   taken:         none
297  *   held on exit:  none
298  * returns: DLM_NOLOCKMGR, or net status
299  */
300 static enum dlm_status dlm_send_remote_lock_request(struct dlm_ctxt *dlm,
301                                                struct dlm_lock_resource *res,
302                                                struct dlm_lock *lock, int flags)
303 {
304         struct dlm_create_lock create;
305         int tmpret, status = 0;
306         enum dlm_status ret;
307 
308         memset(&create, 0, sizeof(create));
309         create.node_idx = dlm->node_num;
310         create.requested_type = lock->ml.type;
311         create.cookie = lock->ml.cookie;
312         create.namelen = res->lockname.len;
313         create.flags = cpu_to_be32(flags);
314         memcpy(create.name, res->lockname.name, create.namelen);
315 
316         tmpret = o2net_send_message(DLM_CREATE_LOCK_MSG, dlm->key, &create,
317                                     sizeof(create), res->owner, &status);
318         if (tmpret >= 0) {
319                 ret = status;
320                 if (ret == DLM_REJECTED) {
321                         mlog(ML_ERROR, "%s: res %.*s, Stale lockres no longer "
322                              "owned by node %u. That node is coming back up "
323                              "currently.\n", dlm->name, create.namelen,
324                              create.name, res->owner);
325                         dlm_print_one_lock_resource(res);
326                         BUG();
327                 }
328         } else {
329                 mlog(ML_ERROR, "%s: res %.*s, Error %d send CREATE LOCK to "
330                      "node %u\n", dlm->name, create.namelen, create.name,
331                      tmpret, res->owner);
332                 if (dlm_is_host_down(tmpret))
333                         ret = DLM_RECOVERING;
334                 else
335                         ret = dlm_err_to_dlm_status(tmpret);
336         }
337 
338         return ret;
339 }
340 
341 void dlm_lock_get(struct dlm_lock *lock)
342 {
343         kref_get(&lock->lock_refs);
344 }
345 
346 void dlm_lock_put(struct dlm_lock *lock)
347 {
348         kref_put(&lock->lock_refs, dlm_lock_release);
349 }
350 
351 static void dlm_lock_release(struct kref *kref)
352 {
353         struct dlm_lock *lock;
354 
355         lock = container_of(kref, struct dlm_lock, lock_refs);
356 
357         BUG_ON(!list_empty(&lock->list));
358         BUG_ON(!list_empty(&lock->ast_list));
359         BUG_ON(!list_empty(&lock->bast_list));
360         BUG_ON(lock->ast_pending);
361         BUG_ON(lock->bast_pending);
362 
363         dlm_lock_detach_lockres(lock);
364 
365         if (lock->lksb_kernel_allocated) {
366                 mlog(0, "freeing kernel-allocated lksb\n");
367                 kfree(lock->lksb);
368         }
369         kmem_cache_free(dlm_lock_cache, lock);
370 }
371 
372 /* associate a lock with it's lockres, getting a ref on the lockres */
373 void dlm_lock_attach_lockres(struct dlm_lock *lock,
374                              struct dlm_lock_resource *res)
375 {
376         dlm_lockres_get(res);
377         lock->lockres = res;
378 }
379 
380 /* drop ref on lockres, if there is still one associated with lock */
381 static void dlm_lock_detach_lockres(struct dlm_lock *lock)
382 {
383         struct dlm_lock_resource *res;
384 
385         res = lock->lockres;
386         if (res) {
387                 lock->lockres = NULL;
388                 mlog(0, "removing lock's lockres reference\n");
389                 dlm_lockres_put(res);
390         }
391 }
392 
393 static void dlm_init_lock(struct dlm_lock *newlock, int type,
394                           u8 node, u64 cookie)
395 {
396         INIT_LIST_HEAD(&newlock->list);
397         INIT_LIST_HEAD(&newlock->ast_list);
398         INIT_LIST_HEAD(&newlock->bast_list);
399         spin_lock_init(&newlock->spinlock);
400         newlock->ml.type = type;
401         newlock->ml.convert_type = LKM_IVMODE;
402         newlock->ml.highest_blocked = LKM_IVMODE;
403         newlock->ml.node = node;
404         newlock->ml.pad1 = 0;
405         newlock->ml.list = 0;
406         newlock->ml.flags = 0;
407         newlock->ast = NULL;
408         newlock->bast = NULL;
409         newlock->astdata = NULL;
410         newlock->ml.cookie = cpu_to_be64(cookie);
411         newlock->ast_pending = 0;
412         newlock->bast_pending = 0;
413         newlock->convert_pending = 0;
414         newlock->lock_pending = 0;
415         newlock->unlock_pending = 0;
416         newlock->cancel_pending = 0;
417         newlock->lksb_kernel_allocated = 0;
418 
419         kref_init(&newlock->lock_refs);
420 }
421 
422 struct dlm_lock * dlm_new_lock(int type, u8 node, u64 cookie,
423                                struct dlm_lockstatus *lksb)
424 {
425         struct dlm_lock *lock;
426         int kernel_allocated = 0;
427 
428         lock = kmem_cache_zalloc(dlm_lock_cache, GFP_NOFS);
429         if (!lock)
430                 return NULL;
431 
432         if (!lksb) {
433                 /* zero memory only if kernel-allocated */
434                 lksb = kzalloc(sizeof(*lksb), GFP_NOFS);
435                 if (!lksb) {
436                         kmem_cache_free(dlm_lock_cache, lock);
437                         return NULL;
438                 }
439                 kernel_allocated = 1;
440         }
441 
442         dlm_init_lock(lock, type, node, cookie);
443         if (kernel_allocated)
444                 lock->lksb_kernel_allocated = 1;
445         lock->lksb = lksb;
446         lksb->lockid = lock;
447         return lock;
448 }
449 
450 /* handler for lock creation net message
451  * locking:
452  *   caller needs:  none
453  *   taken:         takes and drops res->spinlock
454  *   held on exit:  none
455  * returns: DLM_NORMAL, DLM_SYSERR, DLM_IVLOCKID, DLM_NOTQUEUED
456  */
457 int dlm_create_lock_handler(struct o2net_msg *msg, u32 len, void *data,
458                             void **ret_data)
459 {
460         struct dlm_ctxt *dlm = data;
461         struct dlm_create_lock *create = (struct dlm_create_lock *)msg->buf;
462         struct dlm_lock_resource *res = NULL;
463         struct dlm_lock *newlock = NULL;
464         struct dlm_lockstatus *lksb = NULL;
465         enum dlm_status status = DLM_NORMAL;
466         char *name;
467         unsigned int namelen;
468 
469         BUG_ON(!dlm);
470 
471         if (!dlm_grab(dlm))
472                 return DLM_REJECTED;
473 
474         name = create->name;
475         namelen = create->namelen;
476         status = DLM_REJECTED;
477         if (!dlm_domain_fully_joined(dlm)) {
478                 mlog(ML_ERROR, "Domain %s not fully joined, but node %u is "
479                      "sending a create_lock message for lock %.*s!\n",
480                      dlm->name, create->node_idx, namelen, name);
481                 dlm_error(status);
482                 goto leave;
483         }
484 
485         status = DLM_IVBUFLEN;
486         if (namelen > DLM_LOCKID_NAME_MAX) {
487                 dlm_error(status);
488                 goto leave;
489         }
490 
491         status = DLM_SYSERR;
492         newlock = dlm_new_lock(create->requested_type,
493                                create->node_idx,
494                                be64_to_cpu(create->cookie), NULL);
495         if (!newlock) {
496                 dlm_error(status);
497                 goto leave;
498         }
499 
500         lksb = newlock->lksb;
501 
502         if (be32_to_cpu(create->flags) & LKM_GET_LVB) {
503                 lksb->flags |= DLM_LKSB_GET_LVB;
504                 mlog(0, "set DLM_LKSB_GET_LVB flag\n");
505         }
506 
507         status = DLM_IVLOCKID;
508         res = dlm_lookup_lockres(dlm, name, namelen);
509         if (!res) {
510                 dlm_error(status);
511                 goto leave;
512         }
513 
514         spin_lock(&res->spinlock);
515         status = __dlm_lockres_state_to_status(res);
516         spin_unlock(&res->spinlock);
517 
518         if (status != DLM_NORMAL) {
519                 mlog(0, "lockres recovering/migrating/in-progress\n");
520                 goto leave;
521         }
522 
523         dlm_lock_attach_lockres(newlock, res);
524 
525         status = dlmlock_master(dlm, res, newlock, be32_to_cpu(create->flags));
526 leave:
527         if (status != DLM_NORMAL)
528                 if (newlock)
529                         dlm_lock_put(newlock);
530 
531         if (res)
532                 dlm_lockres_put(res);
533 
534         dlm_put(dlm);
535 
536         return status;
537 }
538 
539 
540 /* fetch next node-local (u8 nodenum + u56 cookie) into u64 */
541 static inline void dlm_get_next_cookie(u8 node_num, u64 *cookie)
542 {
543         u64 tmpnode = node_num;
544 
545         /* shift single byte of node num into top 8 bits */
546         tmpnode <<= 56;
547 
548         spin_lock(&dlm_cookie_lock);
549         *cookie = (dlm_next_cookie | tmpnode);
550         if (++dlm_next_cookie & 0xff00000000000000ull) {
551                 mlog(0, "This node's cookie will now wrap!\n");
552                 dlm_next_cookie = 1;
553         }
554         spin_unlock(&dlm_cookie_lock);
555 }
556 
557 enum dlm_status dlmlock(struct dlm_ctxt *dlm, int mode,
558                         struct dlm_lockstatus *lksb, int flags,
559                         const char *name, int namelen, dlm_astlockfunc_t *ast,
560                         void *data, dlm_bastlockfunc_t *bast)
561 {
562         enum dlm_status status;
563         struct dlm_lock_resource *res = NULL;
564         struct dlm_lock *lock = NULL;
565         int convert = 0, recovery = 0;
566 
567         /* yes this function is a mess.
568          * TODO: clean this up.  lots of common code in the
569          *       lock and convert paths, especially in the retry blocks */
570         if (!lksb) {
571                 dlm_error(DLM_BADARGS);
572                 return DLM_BADARGS;
573         }
574 
575         status = DLM_BADPARAM;
576         if (mode != LKM_EXMODE && mode != LKM_PRMODE && mode != LKM_NLMODE) {
577                 dlm_error(status);
578                 goto error;
579         }
580 
581         if (flags & ~LKM_VALID_FLAGS) {
582                 dlm_error(status);
583                 goto error;
584         }
585 
586         convert = (flags & LKM_CONVERT);
587         recovery = (flags & LKM_RECOVERY);
588 
589         if (recovery &&
590             (!dlm_is_recovery_lock(name, namelen) || convert) ) {
591                 dlm_error(status);
592                 goto error;
593         }
594         if (convert && (flags & LKM_LOCAL)) {
595                 mlog(ML_ERROR, "strange LOCAL convert request!\n");
596                 goto error;
597         }
598 
599         if (convert) {
600                 /* CONVERT request */
601 
602                 /* if converting, must pass in a valid dlm_lock */
603                 lock = lksb->lockid;
604                 if (!lock) {
605                         mlog(ML_ERROR, "NULL lock pointer in convert "
606                              "request\n");
607                         goto error;
608                 }
609 
610                 res = lock->lockres;
611                 if (!res) {
612                         mlog(ML_ERROR, "NULL lockres pointer in convert "
613                              "request\n");
614                         goto error;
615                 }
616                 dlm_lockres_get(res);
617 
618                 /* XXX: for ocfs2 purposes, the ast/bast/astdata/lksb are
619                  * static after the original lock call.  convert requests will
620                  * ensure that everything is the same, or return DLM_BADARGS.
621                  * this means that DLM_DENIED_NOASTS will never be returned.
622                  */
623                 if (lock->lksb != lksb || lock->ast != ast ||
624                     lock->bast != bast || lock->astdata != data) {
625                         status = DLM_BADARGS;
626                         mlog(ML_ERROR, "new args:  lksb=%p, ast=%p, bast=%p, "
627                              "astdata=%p\n", lksb, ast, bast, data);
628                         mlog(ML_ERROR, "orig args: lksb=%p, ast=%p, bast=%p, "
629                              "astdata=%p\n", lock->lksb, lock->ast,
630                              lock->bast, lock->astdata);
631                         goto error;
632                 }
633 retry_convert:
634                 dlm_wait_for_recovery(dlm);
635 
636                 if (res->owner == dlm->node_num)
637                         status = dlmconvert_master(dlm, res, lock, flags, mode);
638                 else
639                         status = dlmconvert_remote(dlm, res, lock, flags, mode);
640                 if (status == DLM_RECOVERING || status == DLM_MIGRATING ||
641                     status == DLM_FORWARD) {
642                         /* for now, see how this works without sleeping
643                          * and just retry right away.  I suspect the reco
644                          * or migration will complete fast enough that
645                          * no waiting will be necessary */
646                         mlog(0, "retrying convert with migration/recovery/"
647                              "in-progress\n");
648                         msleep(100);
649                         goto retry_convert;
650                 }
651         } else {
652                 u64 tmpcookie;
653 
654                 /* LOCK request */
655                 status = DLM_BADARGS;
656                 if (!name) {
657                         dlm_error(status);
658                         goto error;
659                 }
660 
661                 status = DLM_IVBUFLEN;
662                 if (namelen > DLM_LOCKID_NAME_MAX || namelen < 1) {
663                         dlm_error(status);
664                         goto error;
665                 }
666 
667                 dlm_get_next_cookie(dlm->node_num, &tmpcookie);
668                 lock = dlm_new_lock(mode, dlm->node_num, tmpcookie, lksb);
669                 if (!lock) {
670                         dlm_error(status);
671                         goto error;
672                 }
673 
674                 if (!recovery)
675                         dlm_wait_for_recovery(dlm);
676 
677                 /* find or create the lock resource */
678                 res = dlm_get_lock_resource(dlm, name, namelen, flags);
679                 if (!res) {
680                         status = DLM_IVLOCKID;
681                         dlm_error(status);
682                         goto error;
683                 }
684 
685                 mlog(0, "type=%d, flags = 0x%x\n", mode, flags);
686                 mlog(0, "creating lock: lock=%p res=%p\n", lock, res);
687 
688                 dlm_lock_attach_lockres(lock, res);
689                 lock->ast = ast;
690                 lock->bast = bast;
691                 lock->astdata = data;
692 
693 retry_lock:
694                 if (flags & LKM_VALBLK) {
695                         mlog(0, "LKM_VALBLK passed by caller\n");
696 
697                         /* LVB requests for non PR, PW or EX locks are
698                          * ignored. */
699                         if (mode < LKM_PRMODE)
700                                 flags &= ~LKM_VALBLK;
701                         else {
702                                 flags |= LKM_GET_LVB;
703                                 lock->lksb->flags |= DLM_LKSB_GET_LVB;
704                         }
705                 }
706 
707                 if (res->owner == dlm->node_num)
708                         status = dlmlock_master(dlm, res, lock, flags);
709                 else
710                         status = dlmlock_remote(dlm, res, lock, flags);
711 
712                 if (status == DLM_RECOVERING || status == DLM_MIGRATING ||
713                     status == DLM_FORWARD) {
714                         msleep(100);
715                         if (recovery) {
716                                 if (status != DLM_RECOVERING)
717                                         goto retry_lock;
718                                 /* wait to see the node go down, then
719                                  * drop down and allow the lockres to
720                                  * get cleaned up.  need to remaster. */
721                                 dlm_wait_for_node_death(dlm, res->owner,
722                                                 DLM_NODE_DEATH_WAIT_MAX);
723                         } else {
724                                 dlm_wait_for_recovery(dlm);
725                                 goto retry_lock;
726                         }
727                 }
728 
729                 /* Inflight taken in dlm_get_lock_resource() is dropped here */
730                 spin_lock(&res->spinlock);
731                 dlm_lockres_drop_inflight_ref(dlm, res);
732                 spin_unlock(&res->spinlock);
733 
734                 dlm_lockres_calc_usage(dlm, res);
735                 dlm_kick_thread(dlm, res);
736 
737                 if (status != DLM_NORMAL) {
738                         lock->lksb->flags &= ~DLM_LKSB_GET_LVB;
739                         if (status != DLM_NOTQUEUED)
740                                 dlm_error(status);
741                         goto error;
742                 }
743         }
744 
745 error:
746         if (status != DLM_NORMAL) {
747                 if (lock && !convert)
748                         dlm_lock_put(lock);
749                 // this is kind of unnecessary
750                 lksb->status = status;
751         }
752 
753         /* put lockres ref from the convert path
754          * or from dlm_get_lock_resource */
755         if (res)
756                 dlm_lockres_put(res);
757 
758         return status;
759 }
760 EXPORT_SYMBOL_GPL(dlmlock);
761 

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