git.oblomov.eu Git - linux-2.6/blob - fs/ocfs2/dlm/dlmunlock.c

   1 /* -*- mode: c; c-basic-offset: 8; -*-
   2  * vim: noexpandtab sw=8 ts=8 sts=0:
   3  *
   4  * dlmunlock.c
   5  *
   6  * underlying calls for unlocking locks
   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 #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 #define MLOG_MASK_PREFIX ML_DLM
  51 #include "cluster/masklog.h"
  52
  53 #define DLM_UNLOCK_FREE_LOCK           0x00000001
  54 #define DLM_UNLOCK_CALL_AST            0x00000002
  55 #define DLM_UNLOCK_REMOVE_LOCK         0x00000004
  56 #define DLM_UNLOCK_REGRANT_LOCK        0x00000008
  57 #define DLM_UNLOCK_CLEAR_CONVERT_TYPE  0x00000010
  58
  59
  60 static enum dlm_status dlm_get_cancel_actions(struct dlm_ctxt *dlm,
  61                                               struct dlm_lock_resource *res,
  62                                               struct dlm_lock *lock,
  63                                               struct dlm_lockstatus *lksb,
  64                                               int *actions);
  65 static enum dlm_status dlm_get_unlock_actions(struct dlm_ctxt *dlm,
  66                                               struct dlm_lock_resource *res,
  67                                               struct dlm_lock *lock,
  68                                               struct dlm_lockstatus *lksb,
  69                                               int *actions);
  70
  71 static enum dlm_status dlm_send_remote_unlock_request(struct dlm_ctxt *dlm,
  72                                                  struct dlm_lock_resource *res,
  73                                                  struct dlm_lock *lock,
  74                                                  struct dlm_lockstatus *lksb,
  75                                                  int flags,
  76                                                  u8 owner);
  77
  78
  79 /*
  80  * according to the spec:
  81  * http://opendlm.sourceforge.net/cvsmirror/opendlm/docs/dlmbook_final.pdf
  82  *
  83  *  flags & LKM_CANCEL != 0: must be converting or blocked
  84  *  flags & LKM_CANCEL == 0: must be granted
  85  *
  86  * So to unlock a converting lock, you must first cancel the
  87  * convert (passing LKM_CANCEL in flags), then call the unlock
  88  * again (with no LKM_CANCEL in flags).
  89  */
  90
  91
  92 /*
  93  * locking:
  94  *   caller needs:  none
  95  *   taken:         res->spinlock and lock->spinlock taken and dropped
  96  *   held on exit:  none
  97  * returns: DLM_NORMAL, DLM_NOLOCKMGR, status from network
  98  * all callers should have taken an extra ref on lock coming in
  99  */
 100 static enum dlm_status dlmunlock_common(struct dlm_ctxt *dlm,
 101                                         struct dlm_lock_resource *res,
 102                                         struct dlm_lock *lock,
 103                                         struct dlm_lockstatus *lksb,
 104                                         int flags, int *call_ast,
 105                                         int master_node)
 106 {
 107         enum dlm_status status;
 108         int actions = 0;
 109         int in_use;
 110         u8 owner;
 111
 112         mlog(0, "master_node = %d, valblk = %d\n", master_node,
 113              flags & LKM_VALBLK);
 114
 115         if (master_node)
 116                 BUG_ON(res->owner != dlm->node_num);
 117         else
 118                 BUG_ON(res->owner == dlm->node_num);
 119
 120         spin_lock(&dlm->spinlock);
 121         /* We want to be sure that we're not freeing a lock
 122          * that still has AST's pending... */
 123         in_use = !list_empty(&lock->ast_list);
 124         spin_unlock(&dlm->spinlock);
 125         if (in_use) {
 126                mlog(ML_ERROR, "lockres %.*s: Someone is calling dlmunlock "
 127                     "while waiting for an ast!", res->lockname.len,
 128                     res->lockname.name);
 129                 return DLM_BADPARAM;
 130         }
 131
 132         spin_lock(&res->spinlock);
 133         if (res->state & DLM_LOCK_RES_IN_PROGRESS) {
 134                 if (master_node) {
 135                         mlog(ML_ERROR, "lockres in progress!\n");
 136                         spin_unlock(&res->spinlock);
 137                         return DLM_FORWARD;
 138                 }
 139                 /* ok for this to sleep if not in a network handler */
 140                 __dlm_wait_on_lockres(res);
 141                 res->state |= DLM_LOCK_RES_IN_PROGRESS;
 142         }
 143         spin_lock(&lock->spinlock);
 144
 145         if (res->state & DLM_LOCK_RES_RECOVERING) {
 146                 status = DLM_RECOVERING;
 147                 goto leave;
 148         }
 149
 150         if (res->state & DLM_LOCK_RES_MIGRATING) {
 151                 status = DLM_MIGRATING;
 152                 goto leave;
 153         }
 154
 155         /* see above for what the spec says about
 156          * LKM_CANCEL and the lock queue state */
 157         if (flags & LKM_CANCEL)
 158                 status = dlm_get_cancel_actions(dlm, res, lock, lksb, &actions);
 159         else
 160                 status = dlm_get_unlock_actions(dlm, res, lock, lksb, &actions);
 161
 162         if (status != DLM_NORMAL && (status != DLM_CANCELGRANT || !master_node))
 163                 goto leave;
 164
 165         /* By now this has been masked out of cancel requests. */
 166         if (flags & LKM_VALBLK) {
 167                 /* make the final update to the lvb */
 168                 if (master_node)
 169                         memcpy(res->lvb, lksb->lvb, DLM_LVB_LEN);
 170                 else
 171                         flags |= LKM_PUT_LVB; /* let the send function
 172                                                * handle it. */
 173         }
 174
 175         if (!master_node) {
 176                 owner = res->owner;
 177                 /* drop locks and send message */
 178                 if (flags & LKM_CANCEL)
 179                         lock->cancel_pending = 1;
 180                 else
 181                         lock->unlock_pending = 1;
 182                 spin_unlock(&lock->spinlock);
 183                 spin_unlock(&res->spinlock);
 184                 status = dlm_send_remote_unlock_request(dlm, res, lock, lksb,
 185                                                         flags, owner);
 186                 spin_lock(&res->spinlock);
 187                 spin_lock(&lock->spinlock);
 188                 /* if the master told us the lock was already granted,
 189                  * let the ast handle all of these actions */
 190                 if (status == DLM_CANCELGRANT) {
 191                         actions &= ~(DLM_UNLOCK_REMOVE_LOCK|
 192                                      DLM_UNLOCK_REGRANT_LOCK|
 193                                      DLM_UNLOCK_CLEAR_CONVERT_TYPE);
 194                 } else if (status == DLM_RECOVERING ||
 195                            status == DLM_MIGRATING ||
 196                            status == DLM_FORWARD) {
 197                         /* must clear the actions because this unlock
 198                          * is about to be retried.  cannot free or do
 199                          * any list manipulation. */
 200                         mlog(0, "%s:%.*s: clearing actions, %s\n",
 201                              dlm->name, res->lockname.len,
 202                              res->lockname.name,
 203                              status==DLM_RECOVERING?"recovering":
 204                              (status==DLM_MIGRATING?"migrating":
 205                               "forward"));
 206                         actions = 0;
 207                 }
 208                 if (flags & LKM_CANCEL)
 209                         lock->cancel_pending = 0;
 210                 else
 211                         lock->unlock_pending = 0;
 212
 213         }
 214
 215         /* get an extra ref on lock.  if we are just switching
 216          * lists here, we dont want the lock to go away. */
 217         dlm_lock_get(lock);
 218
 219         if (actions & DLM_UNLOCK_REMOVE_LOCK) {
 220                 list_del_init(&lock->list);
 221                 dlm_lock_put(lock);
 222         }
 223         if (actions & DLM_UNLOCK_REGRANT_LOCK) {
 224                 dlm_lock_get(lock);
 225                 list_add_tail(&lock->list, &res->granted);
 226         }
 227         if (actions & DLM_UNLOCK_CLEAR_CONVERT_TYPE) {
 228                 mlog(0, "clearing convert_type at %smaster node\n",
 229                      master_node ? "" : "non-");
 230                 lock->ml.convert_type = LKM_IVMODE;
 231         }
 232
 233         /* remove the extra ref on lock */
 234         dlm_lock_put(lock);
 235
 236 leave:
 237         res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
 238         if (!dlm_lock_on_list(&res->converting, lock))
 239                 BUG_ON(lock->ml.convert_type != LKM_IVMODE);
 240         else
 241                 BUG_ON(lock->ml.convert_type == LKM_IVMODE);
 242         spin_unlock(&lock->spinlock);
 243         spin_unlock(&res->spinlock);
 244         wake_up(&res->wq);
 245
 246         /* let the caller's final dlm_lock_put handle the actual kfree */
 247         if (actions & DLM_UNLOCK_FREE_LOCK) {
 248                 /* this should always be coupled with list removal */
 249                 BUG_ON(!(actions & DLM_UNLOCK_REMOVE_LOCK));
 250                 mlog(0, "lock %u:%llu should be gone now! refs=%d\n",
 251                      dlm_get_lock_cookie_node(lock->ml.cookie),
 252                      dlm_get_lock_cookie_seq(lock->ml.cookie),
 253                      atomic_read(&lock->lock_refs.refcount)-1);
 254                 dlm_lock_put(lock);
 255         }
 256         if (actions & DLM_UNLOCK_CALL_AST)
 257                 *call_ast = 1;
 258
 259         /* if cancel or unlock succeeded, lvb work is done */
 260         if (status == DLM_NORMAL)
 261                 lksb->flags &= ~(DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB);
 262
 263         return status;
 264 }
 265
 266 void dlm_commit_pending_unlock(struct dlm_lock_resource *res,
 267                                struct dlm_lock *lock)
 268 {
 269         /* leave DLM_LKSB_PUT_LVB on the lksb so any final
 270          * update of the lvb will be sent to the new master */
 271         list_del_init(&lock->list);
 272 }
 273
 274 void dlm_commit_pending_cancel(struct dlm_lock_resource *res,
 275                                struct dlm_lock *lock)
 276 {
 277         list_move_tail(&lock->list, &res->granted);
 278         lock->ml.convert_type = LKM_IVMODE;
 279 }
 280
 281
 282 static inline enum dlm_status dlmunlock_master(struct dlm_ctxt *dlm,
 283                                           struct dlm_lock_resource *res,
 284                                           struct dlm_lock *lock,
 285                                           struct dlm_lockstatus *lksb,
 286                                           int flags,
 287                                           int *call_ast)
 288 {
 289         return dlmunlock_common(dlm, res, lock, lksb, flags, call_ast, 1);
 290 }
 291
 292 static inline enum dlm_status dlmunlock_remote(struct dlm_ctxt *dlm,
 293                                           struct dlm_lock_resource *res,
 294                                           struct dlm_lock *lock,
 295                                           struct dlm_lockstatus *lksb,
 296                                           int flags, int *call_ast)
 297 {
 298         return dlmunlock_common(dlm, res, lock, lksb, flags, call_ast, 0);
 299 }
 300
 301 /*
 302  * locking:
 303  *   caller needs:  none
 304  *   taken:         none
 305  *   held on exit:  none
 306  * returns: DLM_NORMAL, DLM_NOLOCKMGR, status from network
 307  */
 308 static enum dlm_status dlm_send_remote_unlock_request(struct dlm_ctxt *dlm,
 309                                                  struct dlm_lock_resource *res,
 310                                                  struct dlm_lock *lock,
 311                                                  struct dlm_lockstatus *lksb,
 312                                                  int flags,
 313                                                  u8 owner)
 314 {
 315         struct dlm_unlock_lock unlock;
 316         int tmpret;
 317         enum dlm_status ret;
 318         int status = 0;
 319         struct kvec vec[2];
 320         size_t veclen = 1;
 321
 322         mlog_entry("%.*s\n", res->lockname.len, res->lockname.name);
 323
 324         if (owner == dlm->node_num) {
 325                 /* ended up trying to contact ourself.  this means
 326                  * that the lockres had been remote but became local
 327                  * via a migration.  just retry it, now as local */
 328                 mlog(0, "%s:%.*s: this node became the master due to a "
 329                      "migration, re-evaluate now\n", dlm->name,
 330                      res->lockname.len, res->lockname.name);
 331                 return DLM_FORWARD;
 332         }
 333
 334         memset(&unlock, 0, sizeof(unlock));
 335         unlock.node_idx = dlm->node_num;
 336         unlock.flags = cpu_to_be32(flags);
 337         unlock.cookie = lock->ml.cookie;
 338         unlock.namelen = res->lockname.len;
 339         memcpy(unlock.name, res->lockname.name, unlock.namelen);
 340
 341         vec[0].iov_len = sizeof(struct dlm_unlock_lock);
 342         vec[0].iov_base = &unlock;
 343
 344         if (flags & LKM_PUT_LVB) {
 345                 /* extra data to send if we are updating lvb */
 346                 vec[1].iov_len = DLM_LVB_LEN;
 347                 vec[1].iov_base = lock->lksb->lvb;
 348                 veclen++;
 349         }
 350
 351         tmpret = o2net_send_message_vec(DLM_UNLOCK_LOCK_MSG, dlm->key,
 352                                         vec, veclen, owner, &status);
 353         if (tmpret >= 0) {
 354                 // successfully sent and received
 355                 if (status == DLM_FORWARD)
 356                         mlog(0, "master was in-progress.  retry\n");
 357                 ret = status;
 358         } else {
 359                 mlog_errno(tmpret);
 360                 if (dlm_is_host_down(tmpret)) {
 361                         /* NOTE: this seems strange, but it is what we want.
 362                          * when the master goes down during a cancel or
 363                          * unlock, the recovery code completes the operation
 364                          * as if the master had not died, then passes the
 365                          * updated state to the recovery master.  this thread
 366                          * just needs to finish out the operation and call
 367                          * the unlockast. */
 368                         ret = DLM_NORMAL;
 369                 } else {
 370                         /* something bad.  this will BUG in ocfs2 */
 371                         ret = dlm_err_to_dlm_status(tmpret);
 372                 }
 373         }
 374
 375         return ret;
 376 }
 377
 378 /*
 379  * locking:
 380  *   caller needs:  none
 381  *   taken:         takes and drops res->spinlock
 382  *   held on exit:  none
 383  * returns: DLM_NORMAL, DLM_BADARGS, DLM_IVLOCKID,
 384  *          return value from dlmunlock_master
 385  */
 386 int dlm_unlock_lock_handler(struct o2net_msg *msg, u32 len, void *data)
 387 {
 388         struct dlm_ctxt *dlm = data;
 389         struct dlm_unlock_lock *unlock = (struct dlm_unlock_lock *)msg->buf;
 390         struct dlm_lock_resource *res = NULL;
 391         struct list_head *iter;
 392         struct dlm_lock *lock = NULL;
 393         enum dlm_status status = DLM_NORMAL;
 394         int found = 0, i;
 395         struct dlm_lockstatus *lksb = NULL;
 396         int ignore;
 397         u32 flags;
 398         struct list_head *queue;
 399
 400         flags = be32_to_cpu(unlock->flags);
 401
 402         if (flags & LKM_GET_LVB) {
 403                 mlog(ML_ERROR, "bad args!  GET_LVB specified on unlock!\n");
 404                 return DLM_BADARGS;
 405         }
 406
 407         if ((flags & (LKM_PUT_LVB|LKM_CANCEL)) == (LKM_PUT_LVB|LKM_CANCEL)) {
 408                 mlog(ML_ERROR, "bad args!  cannot modify lvb on a CANCEL "
 409                      "request!\n");
 410                 return DLM_BADARGS;
 411         }
 412
 413         if (unlock->namelen > DLM_LOCKID_NAME_MAX) {
 414                 mlog(ML_ERROR, "Invalid name length in unlock handler!\n");
 415                 return DLM_IVBUFLEN;
 416         }
 417
 418         if (!dlm_grab(dlm))
 419                 return DLM_REJECTED;
 420
 421         mlog_bug_on_msg(!dlm_domain_fully_joined(dlm),
 422                         "Domain %s not fully joined!\n", dlm->name);
 423
 424         mlog(0, "lvb: %s\n", flags & LKM_PUT_LVB ? "put lvb" : "none");
 425
 426         res = dlm_lookup_lockres(dlm, unlock->name, unlock->namelen);
 427         if (!res) {
 428                 /* We assume here that a no lock resource simply means
 429                  * it was migrated away and destroyed before the other
 430                  * node could detect it. */
 431                 mlog(0, "returning DLM_FORWARD -- res no longer exists\n");
 432                 status = DLM_FORWARD;
 433                 goto not_found;
 434         }
 435
 436         queue=&res->granted;
 437         found = 0;
 438         spin_lock(&res->spinlock);
 439         if (res->state & DLM_LOCK_RES_RECOVERING) {
 440                 spin_unlock(&res->spinlock);
 441                 mlog(0, "returning DLM_RECOVERING\n");
 442                 status = DLM_RECOVERING;
 443                 goto leave;
 444         }
 445
 446         if (res->state & DLM_LOCK_RES_MIGRATING) {
 447                 spin_unlock(&res->spinlock);
 448                 mlog(0, "returning DLM_MIGRATING\n");
 449                 status = DLM_MIGRATING;
 450                 goto leave;
 451         }
 452
 453         if (res->owner != dlm->node_num) {
 454                 spin_unlock(&res->spinlock);
 455                 mlog(0, "returning DLM_FORWARD -- not master\n");
 456                 status = DLM_FORWARD;
 457                 goto leave;
 458         }
 459
 460         for (i=0; i<3; i++) {
 461                 list_for_each(iter, queue) {
 462                         lock = list_entry(iter, struct dlm_lock, list);
 463                         if (lock->ml.cookie == unlock->cookie &&
 464                             lock->ml.node == unlock->node_idx) {
 465                                 dlm_lock_get(lock);
 466                                 found = 1;
 467                                 break;
 468                         }
 469                 }
 470                 if (found)
 471                         break;
 472                 /* scan granted -> converting -> blocked queues */
 473                 queue++;
 474         }
 475         spin_unlock(&res->spinlock);
 476         if (!found) {
 477                 status = DLM_IVLOCKID;
 478                 goto not_found;
 479         }
 480
 481         /* lock was found on queue */
 482         lksb = lock->lksb;
 483         if (flags & (LKM_VALBLK|LKM_PUT_LVB) &&
 484             lock->ml.type != LKM_EXMODE)
 485                 flags &= ~(LKM_VALBLK|LKM_PUT_LVB);
 486
 487         /* unlockast only called on originating node */
 488         if (flags & LKM_PUT_LVB) {
 489                 lksb->flags |= DLM_LKSB_PUT_LVB;
 490                 memcpy(&lksb->lvb[0], &unlock->lvb[0], DLM_LVB_LEN);
 491         }
 492
 493         /* if this is in-progress, propagate the DLM_FORWARD
 494          * all the way back out */
 495         status = dlmunlock_master(dlm, res, lock, lksb, flags, &ignore);
 496         if (status == DLM_FORWARD)
 497                 mlog(0, "lockres is in progress\n");
 498
 499         if (flags & LKM_PUT_LVB)
 500                 lksb->flags &= ~DLM_LKSB_PUT_LVB;
 501
 502         dlm_lockres_calc_usage(dlm, res);
 503         dlm_kick_thread(dlm, res);
 504
 505 not_found:
 506         if (!found)
 507                 mlog(ML_ERROR, "failed to find lock to unlock! "
 508                                "cookie=%u:%llu\n",
 509                                dlm_get_lock_cookie_node(unlock->cookie),
 510                                dlm_get_lock_cookie_seq(unlock->cookie));
 511         else
 512                 dlm_lock_put(lock);
 513
 514 leave:
 515         if (res)
 516                 dlm_lockres_put(res);
 517
 518         dlm_put(dlm);
 519
 520         return status;
 521 }
 522
 523
 524 static enum dlm_status dlm_get_cancel_actions(struct dlm_ctxt *dlm,
 525                                               struct dlm_lock_resource *res,
 526                                               struct dlm_lock *lock,
 527                                               struct dlm_lockstatus *lksb,
 528                                               int *actions)
 529 {
 530         enum dlm_status status;
 531
 532         if (dlm_lock_on_list(&res->blocked, lock)) {
 533                 /* cancel this outright */
 534                 status = DLM_NORMAL;
 535                 *actions = (DLM_UNLOCK_CALL_AST |
 536                             DLM_UNLOCK_REMOVE_LOCK);
 537         } else if (dlm_lock_on_list(&res->converting, lock)) {
 538                 /* cancel the request, put back on granted */
 539                 status = DLM_NORMAL;
 540                 *actions = (DLM_UNLOCK_CALL_AST |
 541                             DLM_UNLOCK_REMOVE_LOCK |
 542                             DLM_UNLOCK_REGRANT_LOCK |
 543                             DLM_UNLOCK_CLEAR_CONVERT_TYPE);
 544         } else if (dlm_lock_on_list(&res->granted, lock)) {
 545                 /* too late, already granted. */
 546                 status = DLM_CANCELGRANT;
 547                 *actions = DLM_UNLOCK_CALL_AST;
 548         } else {
 549                 mlog(ML_ERROR, "lock to cancel is not on any list!\n");
 550                 status = DLM_IVLOCKID;
 551                 *actions = 0;
 552         }
 553         return status;
 554 }
 555
 556 static enum dlm_status dlm_get_unlock_actions(struct dlm_ctxt *dlm,
 557                                               struct dlm_lock_resource *res,
 558                                               struct dlm_lock *lock,
 559                                               struct dlm_lockstatus *lksb,
 560                                               int *actions)
 561 {
 562         enum dlm_status status;
 563
 564         /* unlock request */
 565         if (!dlm_lock_on_list(&res->granted, lock)) {
 566                 status = DLM_DENIED;
 567                 dlm_error(status);
 568                 *actions = 0;
 569         } else {
 570                 /* unlock granted lock */
 571                 status = DLM_NORMAL;
 572                 *actions = (DLM_UNLOCK_FREE_LOCK |
 573                             DLM_UNLOCK_CALL_AST |
 574                             DLM_UNLOCK_REMOVE_LOCK);
 575         }
 576         return status;
 577 }
 578
 579 /* there seems to be no point in doing this async
 580  * since (even for the remote case) there is really
 581  * no work to queue up... so just do it and fire the
 582  * unlockast by hand when done... */
 583 enum dlm_status dlmunlock(struct dlm_ctxt *dlm, struct dlm_lockstatus *lksb,
 584                           int flags, dlm_astunlockfunc_t *unlockast, void *data)
 585 {
 586         enum dlm_status status;
 587         struct dlm_lock_resource *res;
 588         struct dlm_lock *lock = NULL;
 589         int call_ast, is_master;
 590
 591         mlog_entry_void();
 592
 593         if (!lksb) {
 594                 dlm_error(DLM_BADARGS);
 595                 return DLM_BADARGS;
 596         }
 597
 598         if (flags & ~(LKM_CANCEL | LKM_VALBLK | LKM_INVVALBLK)) {
 599                 dlm_error(DLM_BADPARAM);
 600                 return DLM_BADPARAM;
 601         }
 602
 603         if ((flags & (LKM_VALBLK | LKM_CANCEL)) == (LKM_VALBLK | LKM_CANCEL)) {
 604                 mlog(0, "VALBLK given with CANCEL: ignoring VALBLK\n");
 605                 flags &= ~LKM_VALBLK;
 606         }
 607
 608         if (!lksb->lockid || !lksb->lockid->lockres) {
 609                 dlm_error(DLM_BADPARAM);
 610                 return DLM_BADPARAM;
 611         }
 612
 613         lock = lksb->lockid;
 614         BUG_ON(!lock);
 615         dlm_lock_get(lock);
 616
 617         res = lock->lockres;
 618         BUG_ON(!res);
 619         dlm_lockres_get(res);
 620 retry:
 621         call_ast = 0;
 622         /* need to retry up here because owner may have changed */
 623         mlog(0, "lock=%p res=%p\n", lock, res);
 624
 625         spin_lock(&res->spinlock);
 626         is_master = (res->owner == dlm->node_num);
 627         if (flags & LKM_VALBLK && lock->ml.type != LKM_EXMODE)
 628                 flags &= ~LKM_VALBLK;
 629         spin_unlock(&res->spinlock);
 630
 631         if (is_master) {
 632                 status = dlmunlock_master(dlm, res, lock, lksb, flags,
 633                                           &call_ast);
 634                 mlog(0, "done calling dlmunlock_master: returned %d, "
 635                      "call_ast is %d\n", status, call_ast);
 636         } else {
 637                 status = dlmunlock_remote(dlm, res, lock, lksb, flags,
 638                                           &call_ast);
 639                 mlog(0, "done calling dlmunlock_remote: returned %d, "
 640                      "call_ast is %d\n", status, call_ast);
 641         }
 642
 643         if (status == DLM_RECOVERING ||
 644             status == DLM_MIGRATING ||
 645             status == DLM_FORWARD) {
 646                 /* We want to go away for a tiny bit to allow recovery
 647                  * / migration to complete on this resource. I don't
 648                  * know of any wait queue we could sleep on as this
 649                  * may be happening on another node. Perhaps the
 650                  * proper solution is to queue up requests on the
 651                  * other end? */
 652
 653                 /* do we want to yield(); ?? */
 654                 msleep(50);
 655
 656                 mlog(0, "retrying unlock due to pending recovery/"
 657                      "migration/in-progress\n");
 658                 goto retry;
 659         }
 660
 661         if (call_ast) {
 662                 mlog(0, "calling unlockast(%p, %d)\n", data, status);
 663                 if (is_master) {
 664                         /* it is possible that there is one last bast
 665                          * pending.  make sure it is flushed, then
 666                          * call the unlockast.
 667                          * not an issue if this is a mastered remotely,
 668                          * since this lock has been removed from the
 669                          * lockres queues and cannot be found. */
 670                         dlm_kick_thread(dlm, NULL);
 671                         wait_event(dlm->ast_wq,
 672                                    dlm_lock_basts_flushed(dlm, lock));
 673                 }
 674                 (*unlockast)(data, status);
 675         }
 676
 677         if (status == DLM_CANCELGRANT)
 678                 status = DLM_NORMAL;
 679
 680         if (status == DLM_NORMAL) {
 681                 mlog(0, "kicking the thread\n");
 682                 dlm_kick_thread(dlm, res);
 683         } else
 684                 dlm_error(status);
 685
 686         dlm_lockres_calc_usage(dlm, res);
 687         dlm_lockres_put(res);
 688         dlm_lock_put(lock);
 689
 690         mlog(0, "returning status=%d!\n", status);
 691         return status;
 692 }
 693 EXPORT_SYMBOL_GPL(dlmunlock);
 694