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/highmem.h>
  32 #include <linux/init.h>
  33 #include <linux/sysctl.h>
  34 #include <linux/random.h>
  35 #include <linux/blkdev.h>
  36 #include <linux/socket.h>
  37 #include <linux/inet.h>
  38 #include <linux/spinlock.h>
  39 #include <linux/delay.h>
  40
  41 #include "cluster/heartbeat.h"
  42 #include "cluster/nodemanager.h"
  43 #include "cluster/tcp.h"
  44
  45 #include "dlmapi.h"
  46 #include "dlmcommon.h"
  47
  48 #define MLOG_MASK_PREFIX ML_DLM
  49 #include "cluster/masklog.h"
  50
  51 #define DLM_UNLOCK_FREE_LOCK           0x00000001
  52 #define DLM_UNLOCK_CALL_AST            0x00000002
  53 #define DLM_UNLOCK_REMOVE_LOCK         0x00000004
  54 #define DLM_UNLOCK_REGRANT_LOCK        0x00000008
  55 #define DLM_UNLOCK_CLEAR_CONVERT_TYPE  0x00000010
  56
  57
  58 static enum dlm_status dlm_get_cancel_actions(struct dlm_ctxt *dlm,
  59                                               struct dlm_lock_resource *res,
  60                                               struct dlm_lock *lock,
  61                                               struct dlm_lockstatus *lksb,
  62                                               int *actions);
  63 static enum dlm_status dlm_get_unlock_actions(struct dlm_ctxt *dlm,
  64                                               struct dlm_lock_resource *res,
  65                                               struct dlm_lock *lock,
  66                                               struct dlm_lockstatus *lksb,
  67                                               int *actions);
  68
  69 static enum dlm_status dlm_send_remote_unlock_request(struct dlm_ctxt *dlm,
  70                                                  struct dlm_lock_resource *res,
  71                                                  struct dlm_lock *lock,
  72                                                  struct dlm_lockstatus *lksb,
  73                                                  int flags,
  74                                                  u8 owner);
  75
  76
  77 /*
  78  * according to the spec:
  79  * http://opendlm.sourceforge.net/cvsmirror/opendlm/docs/dlmbook_final.pdf
  80  *
  81  *  flags & LKM_CANCEL != 0: must be converting or blocked
  82  *  flags & LKM_CANCEL == 0: must be granted
  83  *
  84  * So to unlock a converting lock, you must first cancel the
  85  * convert (passing LKM_CANCEL in flags), then call the unlock
  86  * again (with no LKM_CANCEL in flags).
  87  */
  88
  89
  90 /*
  91  * locking:
  92  *   caller needs:  none
  93  *   taken:         res->spinlock and lock->spinlock taken and dropped
  94  *   held on exit:  none
  95  * returns: DLM_NORMAL, DLM_NOLOCKMGR, status from network
  96  * all callers should have taken an extra ref on lock coming in
  97  */
  98 static enum dlm_status dlmunlock_common(struct dlm_ctxt *dlm,
  99                                         struct dlm_lock_resource *res,
 100                                         struct dlm_lock *lock,
 101                                         struct dlm_lockstatus *lksb,
 102                                         int flags, int *call_ast,
 103                                         int master_node)
 104 {
 105         enum dlm_status status;
 106         int actions = 0;
 107         int in_use;
 108         u8 owner;
 109
 110         mlog(0, "master_node = %d, valblk = %d\n", master_node,
 111              flags & LKM_VALBLK);
 112
 113         if (master_node)
 114                 BUG_ON(res->owner != dlm->node_num);
 115         else
 116                 BUG_ON(res->owner == dlm->node_num);
 117
 118         spin_lock(&dlm->ast_lock);
 119         /* We want to be sure that we're not freeing a lock
 120          * that still has AST's pending... */
 121         in_use = !list_empty(&lock->ast_list);
 122         spin_unlock(&dlm->ast_lock);
 123         if (in_use && !(flags & LKM_CANCEL)) {
 124                mlog(ML_ERROR, "lockres %.*s: Someone is calling dlmunlock "
 125                     "while waiting for an ast!", res->lockname.len,
 126                     res->lockname.name);
 127                 return DLM_BADPARAM;
 128         }
 129
 130         spin_lock(&res->spinlock);
 131         if (res->state & DLM_LOCK_RES_IN_PROGRESS) {
 132                 if (master_node && !(flags & LKM_CANCEL)) {
 133                         mlog(ML_ERROR, "lockres in progress!\n");
 134                         spin_unlock(&res->spinlock);
 135                         return DLM_FORWARD;
 136                 }
 137                 /* ok for this to sleep if not in a network handler */
 138                 __dlm_wait_on_lockres(res);
 139                 res->state |= DLM_LOCK_RES_IN_PROGRESS;
 140         }
 141         spin_lock(&lock->spinlock);
 142
 143         if (res->state & DLM_LOCK_RES_RECOVERING) {
 144                 status = DLM_RECOVERING;
 145                 goto leave;
 146         }
 147
 148         if (res->state & DLM_LOCK_RES_MIGRATING) {
 149                 status = DLM_MIGRATING;
 150                 goto leave;
 151         }
 152
 153         /* see above for what the spec says about
 154          * LKM_CANCEL and the lock queue state */
 155         if (flags & LKM_CANCEL)
 156                 status = dlm_get_cancel_actions(dlm, res, lock, lksb, &actions);
 157         else
 158                 status = dlm_get_unlock_actions(dlm, res, lock, lksb, &actions);
 159
 160         if (status != DLM_NORMAL && (status != DLM_CANCELGRANT || !master_node))
 161                 goto leave;
 162
 163         /* By now this has been masked out of cancel requests. */
 164         if (flags & LKM_VALBLK) {
 165                 /* make the final update to the lvb */
 166                 if (master_node)
 167                         memcpy(res->lvb, lksb->lvb, DLM_LVB_LEN);
 168                 else
 169                         flags |= LKM_PUT_LVB; /* let the send function
 170                                                * handle it. */
 171         }
 172
 173         if (!master_node) {
 174                 owner = res->owner;
 175                 /* drop locks and send message */
 176                 if (flags & LKM_CANCEL)
 177                         lock->cancel_pending = 1;
 178                 else
 179                         lock->unlock_pending = 1;
 180                 spin_unlock(&lock->spinlock);
 181                 spin_unlock(&res->spinlock);
 182                 status = dlm_send_remote_unlock_request(dlm, res, lock, lksb,
 183                                                         flags, owner);
 184                 spin_lock(&res->spinlock);
 185                 spin_lock(&lock->spinlock);
 186                 /* if the master told us the lock was already granted,
 187                  * let the ast handle all of these actions */
 188                 if (status == DLM_CANCELGRANT) {
 189                         actions &= ~(DLM_UNLOCK_REMOVE_LOCK|
 190                                      DLM_UNLOCK_REGRANT_LOCK|
 191                                      DLM_UNLOCK_CLEAR_CONVERT_TYPE);
 192                 } else if (status == DLM_RECOVERING ||
 193                            status == DLM_MIGRATING ||
 194                            status == DLM_FORWARD) {
 195                         /* must clear the actions because this unlock
 196                          * is about to be retried.  cannot free or do
 197                          * any list manipulation. */
 198                         mlog(0, "%s:%.*s: clearing actions, %s\n",
 199                              dlm->name, res->lockname.len,
 200                              res->lockname.name,
 201                              status==DLM_RECOVERING?"recovering":
 202                              (status==DLM_MIGRATING?"migrating":
 203                               "forward"));
 204                         actions = 0;
 205                 }
 206                 if (flags & LKM_CANCEL)
 207                         lock->cancel_pending = 0;
 208                 else
 209                         lock->unlock_pending = 0;
 210
 211         }
 212
 213         /* get an extra ref on lock.  if we are just switching
 214          * lists here, we dont want the lock to go away. */
 215         dlm_lock_get(lock);
 216
 217         if (actions & DLM_UNLOCK_REMOVE_LOCK) {
 218                 list_del_init(&lock->list);
 219                 dlm_lock_put(lock);
 220         }
 221         if (actions & DLM_UNLOCK_REGRANT_LOCK) {
 222                 dlm_lock_get(lock);
 223                 list_add_tail(&lock->list, &res->granted);
 224         }
 225         if (actions & DLM_UNLOCK_CLEAR_CONVERT_TYPE) {
 226                 mlog(0, "clearing convert_type at %smaster node\n",
 227                      master_node ? "" : "non-");
 228                 lock->ml.convert_type = LKM_IVMODE;
 229         }
 230
 231         /* remove the extra ref on lock */
 232         dlm_lock_put(lock);
 233
 234 leave:
 235         res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
 236         if (!dlm_lock_on_list(&res->converting, lock))
 237                 BUG_ON(lock->ml.convert_type != LKM_IVMODE);
 238         else
 239                 BUG_ON(lock->ml.convert_type == LKM_IVMODE);
 240         spin_unlock(&lock->spinlock);
 241         spin_unlock(&res->spinlock);
 242         wake_up(&res->wq);
 243
 244         /* let the caller's final dlm_lock_put handle the actual kfree */
 245         if (actions & DLM_UNLOCK_FREE_LOCK) {
 246                 /* this should always be coupled with list removal */
 247                 BUG_ON(!(actions & DLM_UNLOCK_REMOVE_LOCK));
 248                 mlog(0, "lock %u:%llu should be gone now! refs=%d\n",
 249                      dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
 250                      dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
 251                      atomic_read(&lock->lock_refs.refcount)-1);
 252                 dlm_lock_put(lock);
 253         }
 254         if (actions & DLM_UNLOCK_CALL_AST)
 255                 *call_ast = 1;
 256
 257         /* if cancel or unlock succeeded, lvb work is done */
 258         if (status == DLM_NORMAL)
 259                 lksb->flags &= ~(DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB);
 260
 261         return status;
 262 }
 263
 264 void dlm_commit_pending_unlock(struct dlm_lock_resource *res,
 265                                struct dlm_lock *lock)
 266 {
 267         /* leave DLM_LKSB_PUT_LVB on the lksb so any final
 268          * update of the lvb will be sent to the new master */
 269         list_del_init(&lock->list);
 270 }
 271
 272 void dlm_commit_pending_cancel(struct dlm_lock_resource *res,
 273                                struct dlm_lock *lock)
 274 {
 275         list_move_tail(&lock->list, &res->granted);
 276         lock->ml.convert_type = LKM_IVMODE;
 277 }
 278
 279
 280 static inline enum dlm_status dlmunlock_master(struct dlm_ctxt *dlm,
 281                                           struct dlm_lock_resource *res,
 282                                           struct dlm_lock *lock,
 283                                           struct dlm_lockstatus *lksb,
 284                                           int flags,
 285                                           int *call_ast)
 286 {
 287         return dlmunlock_common(dlm, res, lock, lksb, flags, call_ast, 1);
 288 }
 289
 290 static inline enum dlm_status dlmunlock_remote(struct dlm_ctxt *dlm,
 291                                           struct dlm_lock_resource *res,
 292                                           struct dlm_lock *lock,
 293                                           struct dlm_lockstatus *lksb,
 294                                           int flags, int *call_ast)
 295 {
 296         return dlmunlock_common(dlm, res, lock, lksb, flags, call_ast, 0);
 297 }
 298
 299 /*
 300  * locking:
 301  *   caller needs:  none
 302  *   taken:         none
 303  *   held on exit:  none
 304  * returns: DLM_NORMAL, DLM_NOLOCKMGR, status from network
 305  */
 306 static enum dlm_status dlm_send_remote_unlock_request(struct dlm_ctxt *dlm,
 307                                                  struct dlm_lock_resource *res,
 308                                                  struct dlm_lock *lock,
 309                                                  struct dlm_lockstatus *lksb,
 310                                                  int flags,
 311                                                  u8 owner)
 312 {
 313         struct dlm_unlock_lock unlock;
 314         int tmpret;
 315         enum dlm_status ret;
 316         int status = 0;
 317         struct kvec vec[2];
 318         size_t veclen = 1;
 319
 320         mlog_entry("%.*s\n", res->lockname.len, res->lockname.name);
 321
 322         if (owner == dlm->node_num) {
 323                 /* ended up trying to contact ourself.  this means
 324                  * that the lockres had been remote but became local
 325                  * via a migration.  just retry it, now as local */
 326                 mlog(0, "%s:%.*s: this node became the master due to a "
 327                      "migration, re-evaluate now\n", dlm->name,
 328                      res->lockname.len, res->lockname.name);
 329                 return DLM_FORWARD;
 330         }
 331
 332         memset(&unlock, 0, sizeof(unlock));
 333         unlock.node_idx = dlm->node_num;
 334         unlock.flags = cpu_to_be32(flags);
 335         unlock.cookie = lock->ml.cookie;
 336         unlock.namelen = res->lockname.len;
 337         memcpy(unlock.name, res->lockname.name, unlock.namelen);
 338
 339         vec[0].iov_len = sizeof(struct dlm_unlock_lock);
 340         vec[0].iov_base = &unlock;
 341
 342         if (flags & LKM_PUT_LVB) {
 343                 /* extra data to send if we are updating lvb */
 344                 vec[1].iov_len = DLM_LVB_LEN;
 345                 vec[1].iov_base = lock->lksb->lvb;
 346                 veclen++;
 347         }
 348
 349         tmpret = o2net_send_message_vec(DLM_UNLOCK_LOCK_MSG, dlm->key,
 350                                         vec, veclen, owner, &status);
 351         if (tmpret >= 0) {
 352                 // successfully sent and received
 353                 if (status == DLM_FORWARD)
 354                         mlog(0, "master was in-progress.  retry\n");
 355                 ret = status;
 356         } else {
 357                 mlog_errno(tmpret);
 358                 if (dlm_is_host_down(tmpret)) {
 359                         /* NOTE: this seems strange, but it is what we want.
 360                          * when the master goes down during a cancel or
 361                          * unlock, the recovery code completes the operation
 362                          * as if the master had not died, then passes the
 363                          * updated state to the recovery master.  this thread
 364                          * just needs to finish out the operation and call
 365                          * the unlockast. */
 366                         ret = DLM_NORMAL;
 367                 } else {
 368                         /* something bad.  this will BUG in ocfs2 */
 369                         ret = dlm_err_to_dlm_status(tmpret);
 370                 }
 371         }
 372
 373         return ret;
 374 }
 375
 376 /*
 377  * locking:
 378  *   caller needs:  none
 379  *   taken:         takes and drops res->spinlock
 380  *   held on exit:  none
 381  * returns: DLM_NORMAL, DLM_BADARGS, DLM_IVLOCKID,
 382  *          return value from dlmunlock_master
 383  */
 384 int dlm_unlock_lock_handler(struct o2net_msg *msg, u32 len, void *data,
 385                             void **ret_data)
 386 {
 387         struct dlm_ctxt *dlm = data;
 388         struct dlm_unlock_lock *unlock = (struct dlm_unlock_lock *)msg->buf;
 389         struct dlm_lock_resource *res = NULL;
 390         struct list_head *iter;
 391         struct dlm_lock *lock = NULL;
 392         enum dlm_status status = DLM_NORMAL;
 393         int found = 0, i;
 394         struct dlm_lockstatus *lksb = NULL;
 395         int ignore;
 396         u32 flags;
 397         struct list_head *queue;
 398
 399         flags = be32_to_cpu(unlock->flags);
 400
 401         if (flags & LKM_GET_LVB) {
 402                 mlog(ML_ERROR, "bad args!  GET_LVB specified on unlock!\n");
 403                 return DLM_BADARGS;
 404         }
 405
 406         if ((flags & (LKM_PUT_LVB|LKM_CANCEL)) == (LKM_PUT_LVB|LKM_CANCEL)) {
 407                 mlog(ML_ERROR, "bad args!  cannot modify lvb on a CANCEL "
 408                      "request!\n");
 409                 return DLM_BADARGS;
 410         }
 411
 412         if (unlock->namelen > DLM_LOCKID_NAME_MAX) {
 413                 mlog(ML_ERROR, "Invalid name length in unlock handler!\n");
 414                 return DLM_IVBUFLEN;
 415         }
 416
 417         if (!dlm_grab(dlm))
 418                 return DLM_REJECTED;
 419
 420         mlog_bug_on_msg(!dlm_domain_fully_joined(dlm),
 421                         "Domain %s not fully joined!\n", dlm->name);
 422
 423         mlog(0, "lvb: %s\n", flags & LKM_PUT_LVB ? "put lvb" : "none");
 424
 425         res = dlm_lookup_lockres(dlm, unlock->name, unlock->namelen);
 426         if (!res) {
 427                 /* We assume here that a no lock resource simply means
 428                  * it was migrated away and destroyed before the other
 429                  * node could detect it. */
 430                 mlog(0, "returning DLM_FORWARD -- res no longer exists\n");
 431                 status = DLM_FORWARD;
 432                 goto not_found;
 433         }
 434
 435         queue=&res->granted;
 436         found = 0;
 437         spin_lock(&res->spinlock);
 438         if (res->state & DLM_LOCK_RES_RECOVERING) {
 439                 spin_unlock(&res->spinlock);
 440                 mlog(0, "returning DLM_RECOVERING\n");
 441                 status = DLM_RECOVERING;
 442                 goto leave;
 443         }
 444
 445         if (res->state & DLM_LOCK_RES_MIGRATING) {
 446                 spin_unlock(&res->spinlock);
 447                 mlog(0, "returning DLM_MIGRATING\n");
 448                 status = DLM_MIGRATING;
 449                 goto leave;
 450         }
 451
 452         if (res->owner != dlm->node_num) {
 453                 spin_unlock(&res->spinlock);
 454                 mlog(0, "returning DLM_FORWARD -- not master\n");
 455                 status = DLM_FORWARD;
 456                 goto leave;
 457         }
 458
 459         for (i=0; i<3; i++) {
 460                 list_for_each(iter, queue) {
 461                         lock = list_entry(iter, struct dlm_lock, list);
 462                         if (lock->ml.cookie == unlock->cookie &&
 463                             lock->ml.node == unlock->node_idx) {
 464                                 dlm_lock_get(lock);
 465                                 found = 1;
 466                                 break;
 467                         }
 468                 }
 469                 if (found)
 470                         break;
 471                 /* scan granted -> converting -> blocked queues */
 472                 queue++;
 473         }
 474         spin_unlock(&res->spinlock);
 475         if (!found) {
 476                 status = DLM_IVLOCKID;
 477                 goto not_found;
 478         }
 479
 480         /* lock was found on queue */
 481         lksb = lock->lksb;
 482         if (flags & (LKM_VALBLK|LKM_PUT_LVB) &&
 483             lock->ml.type != LKM_EXMODE)
 484                 flags &= ~(LKM_VALBLK|LKM_PUT_LVB);
 485
 486         /* unlockast only called on originating node */
 487         if (flags & LKM_PUT_LVB) {
 488                 lksb->flags |= DLM_LKSB_PUT_LVB;
 489                 memcpy(&lksb->lvb[0], &unlock->lvb[0], DLM_LVB_LEN);
 490         }
 491
 492         /* if this is in-progress, propagate the DLM_FORWARD
 493          * all the way back out */
 494         status = dlmunlock_master(dlm, res, lock, lksb, flags, &ignore);
 495         if (status == DLM_FORWARD)
 496                 mlog(0, "lockres is in progress\n");
 497
 498         if (flags & LKM_PUT_LVB)
 499                 lksb->flags &= ~DLM_LKSB_PUT_LVB;
 500
 501         dlm_lockres_calc_usage(dlm, res);
 502         dlm_kick_thread(dlm, res);
 503
 504 not_found:
 505         if (!found)
 506                 mlog(ML_ERROR, "failed to find lock to unlock! "
 507                                "cookie=%u:%llu\n",
 508                      dlm_get_lock_cookie_node(be64_to_cpu(unlock->cookie)),
 509                      dlm_get_lock_cookie_seq(be64_to_cpu(unlock->cookie)));
 510         else
 511                 dlm_lock_put(lock);
 512
 513 leave:
 514         if (res)
 515                 dlm_lockres_put(res);
 516
 517         dlm_put(dlm);
 518
 519         return status;
 520 }
 521
 522
 523 static enum dlm_status dlm_get_cancel_actions(struct dlm_ctxt *dlm,
 524                                               struct dlm_lock_resource *res,
 525                                               struct dlm_lock *lock,
 526                                               struct dlm_lockstatus *lksb,
 527                                               int *actions)
 528 {
 529         enum dlm_status status;
 530
 531         if (dlm_lock_on_list(&res->blocked, lock)) {
 532                 /* cancel this outright */
 533                 status = DLM_NORMAL;
 534                 *actions = (DLM_UNLOCK_CALL_AST |
 535                             DLM_UNLOCK_REMOVE_LOCK);
 536         } else if (dlm_lock_on_list(&res->converting, lock)) {
 537                 /* cancel the request, put back on granted */
 538                 status = DLM_NORMAL;
 539                 *actions = (DLM_UNLOCK_CALL_AST |
 540                             DLM_UNLOCK_REMOVE_LOCK |
 541                             DLM_UNLOCK_REGRANT_LOCK |
 542                             DLM_UNLOCK_CLEAR_CONVERT_TYPE);
 543         } else if (dlm_lock_on_list(&res->granted, lock)) {
 544                 /* too late, already granted. */
 545                 status = DLM_CANCELGRANT;
 546                 *actions = DLM_UNLOCK_CALL_AST;
 547         } else {
 548                 mlog(ML_ERROR, "lock to cancel is not on any list!\n");
 549                 status = DLM_IVLOCKID;
 550                 *actions = 0;
 551         }
 552         return status;
 553 }
 554
 555 static enum dlm_status dlm_get_unlock_actions(struct dlm_ctxt *dlm,
 556                                               struct dlm_lock_resource *res,
 557                                               struct dlm_lock *lock,
 558                                               struct dlm_lockstatus *lksb,
 559                                               int *actions)
 560 {
 561         enum dlm_status status;
 562
 563         /* unlock request */
 564         if (!dlm_lock_on_list(&res->granted, lock)) {
 565                 status = DLM_DENIED;
 566                 dlm_error(status);
 567                 *actions = 0;
 568         } else {
 569                 /* unlock granted lock */
 570                 status = DLM_NORMAL;
 571                 *actions = (DLM_UNLOCK_FREE_LOCK |
 572                             DLM_UNLOCK_CALL_AST |
 573                             DLM_UNLOCK_REMOVE_LOCK);
 574         }
 575         return status;
 576 }
 577
 578 /* there seems to be no point in doing this async
 579  * since (even for the remote case) there is really
 580  * no work to queue up... so just do it and fire the
 581  * unlockast by hand when done... */
 582 enum dlm_status dlmunlock(struct dlm_ctxt *dlm, struct dlm_lockstatus *lksb,
 583                           int flags, dlm_astunlockfunc_t *unlockast, void *data)
 584 {
 585         enum dlm_status status;
 586         struct dlm_lock_resource *res;
 587         struct dlm_lock *lock = NULL;
 588         int call_ast, is_master;
 589
 590         mlog_entry_void();
 591
 592         if (!lksb) {
 593                 dlm_error(DLM_BADARGS);
 594                 return DLM_BADARGS;
 595         }
 596
 597         if (flags & ~(LKM_CANCEL | LKM_VALBLK | LKM_INVVALBLK)) {
 598                 dlm_error(DLM_BADPARAM);
 599                 return DLM_BADPARAM;
 600         }
 601
 602         if ((flags & (LKM_VALBLK | LKM_CANCEL)) == (LKM_VALBLK | LKM_CANCEL)) {
 603                 mlog(0, "VALBLK given with CANCEL: ignoring VALBLK\n");
 604                 flags &= ~LKM_VALBLK;
 605         }
 606
 607         if (!lksb->lockid || !lksb->lockid->lockres) {
 608                 dlm_error(DLM_BADPARAM);
 609                 return DLM_BADPARAM;
 610         }
 611
 612         lock = lksb->lockid;
 613         BUG_ON(!lock);
 614         dlm_lock_get(lock);
 615
 616         res = lock->lockres;
 617         BUG_ON(!res);
 618         dlm_lockres_get(res);
 619 retry:
 620         call_ast = 0;
 621         /* need to retry up here because owner may have changed */
 622         mlog(0, "lock=%p res=%p\n", lock, res);
 623
 624         spin_lock(&res->spinlock);
 625         is_master = (res->owner == dlm->node_num);
 626         if (flags & LKM_VALBLK && lock->ml.type != LKM_EXMODE)
 627                 flags &= ~LKM_VALBLK;
 628         spin_unlock(&res->spinlock);
 629
 630         if (is_master) {
 631                 status = dlmunlock_master(dlm, res, lock, lksb, flags,
 632                                           &call_ast);
 633                 mlog(0, "done calling dlmunlock_master: returned %d, "
 634                      "call_ast is %d\n", status, call_ast);
 635         } else {
 636                 status = dlmunlock_remote(dlm, res, lock, lksb, flags,
 637                                           &call_ast);
 638                 mlog(0, "done calling dlmunlock_remote: returned %d, "
 639                      "call_ast is %d\n", status, call_ast);
 640         }
 641
 642         if (status == DLM_RECOVERING ||
 643             status == DLM_MIGRATING ||
 644             status == DLM_FORWARD) {
 645                 /* We want to go away for a tiny bit to allow recovery
 646                  * / migration to complete on this resource. I don't
 647                  * know of any wait queue we could sleep on as this
 648                  * may be happening on another node. Perhaps the
 649                  * proper solution is to queue up requests on the
 650                  * other end? */
 651
 652                 /* do we want to yield(); ?? */
 653                 msleep(50);
 654
 655                 mlog(0, "retrying unlock due to pending recovery/"
 656                      "migration/in-progress\n");
 657                 goto retry;
 658         }
 659
 660         if (call_ast) {
 661                 mlog(0, "calling unlockast(%p, %d)\n", data, status);
 662                 if (is_master) {
 663                         /* it is possible that there is one last bast
 664                          * pending.  make sure it is flushed, then
 665                          * call the unlockast.
 666                          * not an issue if this is a mastered remotely,
 667                          * since this lock has been removed from the
 668                          * lockres queues and cannot be found. */
 669                         dlm_kick_thread(dlm, NULL);
 670                         wait_event(dlm->ast_wq,
 671                                    dlm_lock_basts_flushed(dlm, lock));
 672                 }
 673                 (*unlockast)(data, status);
 674         }
 675
 676         if (status == DLM_CANCELGRANT)
 677                 status = DLM_NORMAL;
 678
 679         if (status == DLM_NORMAL) {
 680                 mlog(0, "kicking the thread\n");
 681                 dlm_kick_thread(dlm, res);
 682         } else
 683                 dlm_error(status);
 684
 685         dlm_lockres_calc_usage(dlm, res);
 686         dlm_lockres_put(res);
 687         dlm_lock_put(lock);
 688
 689         mlog(0, "returning status=%d!\n", status);
 690         return status;
 691 }
 692 EXPORT_SYMBOL_GPL(dlmunlock);
 693