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