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