kernel/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                            status == DLM_NOLOCKMGR
 196                            ) {
 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                                 (status == DLM_FORWARD ? "forward" :
 206                                                 "nolockmanager")));
 207                         actions = 0;
 208                 }
 209                 if (flags & LKM_CANCEL)
 210                         lock->cancel_pending = 0;
 211                 else
 212                         lock->unlock_pending = 0;
 213
 214         }
 215
 216         /* get an extra ref on lock.  if we are just switching
 217          * lists here, we dont want the lock to go away. */
 218         dlm_lock_get(lock);
 219
 220         if (actions & DLM_UNLOCK_REMOVE_LOCK) {
 221                 list_del_init(&lock->list);
 222                 dlm_lock_put(lock);
 223         }
 224         if (actions & DLM_UNLOCK_REGRANT_LOCK) {
 225                 dlm_lock_get(lock);
 226                 list_add_tail(&lock->list, &res->granted);
 227         }
 228         if (actions & DLM_UNLOCK_CLEAR_CONVERT_TYPE) {
 229                 mlog(0, "clearing convert_type at %smaster node\n",
 230                      master_node ? "" : "non-");
 231                 lock->ml.convert_type = LKM_IVMODE;
 232         }
 233
 234         /* remove the extra ref on lock */
 235         dlm_lock_put(lock);
 236
 237 leave:
 238         res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
 239         if (!dlm_lock_on_list(&res->converting, lock))
 240                 BUG_ON(lock->ml.convert_type != LKM_IVMODE);
 241         else
 242                 BUG_ON(lock->ml.convert_type == LKM_IVMODE);
 243         spin_unlock(&lock->spinlock);
 244         spin_unlock(&res->spinlock);
 245         wake_up(&res->wq);
 246
 247         /* let the caller's final dlm_lock_put handle the actual kfree */
 248         if (actions & DLM_UNLOCK_FREE_LOCK) {
 249                 /* this should always be coupled with list removal */
 250                 BUG_ON(!(actions & DLM_UNLOCK_REMOVE_LOCK));
 251                 mlog(0, "lock %u:%llu should be gone now! refs=%d\n",
 252                      dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
 253                      dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
 254                      atomic_read(&lock->lock_refs.refcount)-1);
 255                 dlm_lock_put(lock);
 256         }
 257         if (actions & DLM_UNLOCK_CALL_AST)
 258                 *call_ast = 1;
 259
 260         /* if cancel or unlock succeeded, lvb work is done */
 261         if (status == DLM_NORMAL)
 262                 lksb->flags &= ~(DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB);
 263
 264         return status;
 265 }
 266
 267 void dlm_commit_pending_unlock(struct dlm_lock_resource *res,
 268                                struct dlm_lock *lock)
 269 {
 270         /* leave DLM_LKSB_PUT_LVB on the lksb so any final
 271          * update of the lvb will be sent to the new master */
 272         list_del_init(&lock->list);
 273 }
 274
 275 void dlm_commit_pending_cancel(struct dlm_lock_resource *res,
 276                                struct dlm_lock *lock)
 277 {
 278         list_move_tail(&lock->list, &res->granted);
 279         lock->ml.convert_type = LKM_IVMODE;
 280 }
 281
 282
 283 static inline enum dlm_status dlmunlock_master(struct dlm_ctxt *dlm,
 284                                           struct dlm_lock_resource *res,
 285                                           struct dlm_lock *lock,
 286                                           struct dlm_lockstatus *lksb,
 287                                           int flags,
 288                                           int *call_ast)
 289 {
 290         return dlmunlock_common(dlm, res, lock, lksb, flags, call_ast, 1);
 291 }
 292
 293 static inline enum dlm_status dlmunlock_remote(struct dlm_ctxt *dlm,
 294                                           struct dlm_lock_resource *res,
 295                                           struct dlm_lock *lock,
 296                                           struct dlm_lockstatus *lksb,
 297                                           int flags, int *call_ast)
 298 {
 299         return dlmunlock_common(dlm, res, lock, lksb, flags, call_ast, 0);
 300 }
 301
 302 /*
 303  * locking:
 304  *   caller needs:  none
 305  *   taken:         none
 306  *   held on exit:  none
 307  * returns: DLM_NORMAL, DLM_NOLOCKMGR, status from network
 308  */
 309 static enum dlm_status dlm_send_remote_unlock_request(struct dlm_ctxt *dlm,
 310                                                  struct dlm_lock_resource *res,
 311                                                  struct dlm_lock *lock,
 312                                                  struct dlm_lockstatus *lksb,
 313                                                  int flags,
 314                                                  u8 owner)
 315 {
 316         struct dlm_unlock_lock unlock;
 317         int tmpret;
 318         enum dlm_status ret;
 319         int status = 0;
 320         struct kvec vec[2];
 321         size_t veclen = 1;
 322
 323         mlog(0, "%.*s\n", res->lockname.len, res->lockname.name);
 324
 325         if (owner == dlm->node_num) {
 326                 /* ended up trying to contact ourself.  this means
 327                  * that the lockres had been remote but became local
 328                  * via a migration.  just retry it, now as local */
 329                 mlog(0, "%s:%.*s: this node became the master due to a "
 330                      "migration, re-evaluate now\n", dlm->name,
 331                      res->lockname.len, res->lockname.name);
 332                 return DLM_FORWARD;
 333         }
 334
 335         memset(&unlock, 0, sizeof(unlock));
 336         unlock.node_idx = dlm->node_num;
 337         unlock.flags = cpu_to_be32(flags);
 338         unlock.cookie = lock->ml.cookie;
 339         unlock.namelen = res->lockname.len;
 340         memcpy(unlock.name, res->lockname.name, unlock.namelen);
 341
 342         vec[0].iov_len = sizeof(struct dlm_unlock_lock);
 343         vec[0].iov_base = &unlock;
 344
 345         if (flags & LKM_PUT_LVB) {
 346                 /* extra data to send if we are updating lvb */
 347                 vec[1].iov_len = DLM_LVB_LEN;
 348                 vec[1].iov_base = lock->lksb->lvb;
 349                 veclen++;
 350         }
 351
 352         tmpret = o2net_send_message_vec(DLM_UNLOCK_LOCK_MSG, dlm->key,
 353                                         vec, veclen, owner, &status);
 354         if (tmpret >= 0) {
 355                 // successfully sent and received
 356                 if (status == DLM_FORWARD)
 357                         mlog(0, "master was in-progress.  retry\n");
 358                 ret = status;
 359         } else {
 360                 mlog(ML_ERROR, "Error %d when sending message %u (key 0x%x) to "
 361                      "node %u\n", tmpret, DLM_UNLOCK_LOCK_MSG, dlm->key, owner);
 362                 if (dlm_is_host_down(tmpret)) {
 363                         /* NOTE: this seems strange, but it is what we want.
 364                          * when the master goes down during a cancel or
 365                          * unlock, the recovery code completes the operation
 366                          * as if the master had not died, then passes the
 367                          * updated state to the recovery master.  this thread
 368                          * just needs to finish out the operation and call
 369                          * the unlockast. */
 370                         if (dlm_is_node_dead(dlm, owner))
 371                                 ret = DLM_NORMAL;
 372                         else
 373                                 ret = DLM_NOLOCKMGR;
 374                 } else {
 375                         /* something bad.  this will BUG in ocfs2 */
 376                         ret = dlm_err_to_dlm_status(tmpret);
 377                 }
 378         }
 379
 380         return ret;
 381 }
 382
 383 /*
 384  * locking:
 385  *   caller needs:  none
 386  *   taken:         takes and drops res->spinlock
 387  *   held on exit:  none
 388  * returns: DLM_NORMAL, DLM_BADARGS, DLM_IVLOCKID,
 389  *          return value from dlmunlock_master
 390  */
 391 int dlm_unlock_lock_handler(struct o2net_msg *msg, u32 len, void *data,
 392                             void **ret_data)
 393 {
 394         struct dlm_ctxt *dlm = data;
 395         struct dlm_unlock_lock *unlock = (struct dlm_unlock_lock *)msg->buf;
 396         struct dlm_lock_resource *res = NULL;
 397         struct dlm_lock *lock = NULL;
 398         enum dlm_status status = DLM_NORMAL;
 399         int found = 0, i;
 400         struct dlm_lockstatus *lksb = NULL;
 401         int ignore;
 402         u32 flags;
 403         struct list_head *queue;
 404
 405         flags = be32_to_cpu(unlock->flags);
 406
 407         if (flags & LKM_GET_LVB) {
 408                 mlog(ML_ERROR, "bad args!  GET_LVB specified on unlock!\n");
 409                 return DLM_BADARGS;
 410         }
 411
 412         if ((flags & (LKM_PUT_LVB|LKM_CANCEL)) == (LKM_PUT_LVB|LKM_CANCEL)) {
 413                 mlog(ML_ERROR, "bad args!  cannot modify lvb on a CANCEL "
 414                      "request!\n");
 415                 return DLM_BADARGS;
 416         }
 417
 418         if (unlock->namelen > DLM_LOCKID_NAME_MAX) {
 419                 mlog(ML_ERROR, "Invalid name length in unlock handler!\n");
 420                 return DLM_IVBUFLEN;
 421         }
 422
 423         if (!dlm_grab(dlm))
 424                 return DLM_REJECTED;
 425
 426         mlog_bug_on_msg(!dlm_domain_fully_joined(dlm),
 427                         "Domain %s not fully joined!\n", dlm->name);
 428
 429         mlog(0, "lvb: %s\n", flags & LKM_PUT_LVB ? "put lvb" : "none");
 430
 431         res = dlm_lookup_lockres(dlm, unlock->name, unlock->namelen);
 432         if (!res) {
 433                 /* We assume here that a no lock resource simply means
 434                  * it was migrated away and destroyed before the other
 435                  * node could detect it. */
 436                 mlog(0, "returning DLM_FORWARD -- res no longer exists\n");
 437                 status = DLM_FORWARD;
 438                 goto not_found;
 439         }
 440
 441         queue=&res->granted;
 442         found = 0;
 443         spin_lock(&res->spinlock);
 444         if (res->state & DLM_LOCK_RES_RECOVERING) {
 445                 spin_unlock(&res->spinlock);
 446                 mlog(0, "returning DLM_RECOVERING\n");
 447                 status = DLM_RECOVERING;
 448                 goto leave;
 449         }
 450
 451         if (res->state & DLM_LOCK_RES_MIGRATING) {
 452                 spin_unlock(&res->spinlock);
 453                 mlog(0, "returning DLM_MIGRATING\n");
 454                 status = DLM_MIGRATING;
 455                 goto leave;
 456         }
 457
 458         if (res->owner != dlm->node_num) {
 459                 spin_unlock(&res->spinlock);
 460                 mlog(0, "returning DLM_FORWARD -- not master\n");
 461                 status = DLM_FORWARD;
 462                 goto leave;
 463         }
 464
 465         for (i=0; i<3; i++) {
 466                 list_for_each_entry(lock, queue, list) {
 467                         if (lock->ml.cookie == unlock->cookie &&
 468                             lock->ml.node == unlock->node_idx) {
 469                                 dlm_lock_get(lock);
 470                                 found = 1;
 471                                 break;
 472                         }
 473                 }
 474                 if (found)
 475                         break;
 476                 /* scan granted -> converting -> blocked queues */
 477                 queue++;
 478         }
 479         spin_unlock(&res->spinlock);
 480         if (!found) {
 481                 status = DLM_IVLOCKID;
 482                 goto not_found;
 483         }
 484
 485         /* lock was found on queue */
 486         lksb = lock->lksb;
 487         if (flags & (LKM_VALBLK|LKM_PUT_LVB) &&
 488             lock->ml.type != LKM_EXMODE)
 489                 flags &= ~(LKM_VALBLK|LKM_PUT_LVB);
 490
 491         /* unlockast only called on originating node */
 492         if (flags & LKM_PUT_LVB) {
 493                 lksb->flags |= DLM_LKSB_PUT_LVB;
 494                 memcpy(&lksb->lvb[0], &unlock->lvb[0], DLM_LVB_LEN);
 495         }
 496
 497         /* if this is in-progress, propagate the DLM_FORWARD
 498          * all the way back out */
 499         status = dlmunlock_master(dlm, res, lock, lksb, flags, &ignore);
 500         if (status == DLM_FORWARD)
 501                 mlog(0, "lockres is in progress\n");
 502
 503         if (flags & LKM_PUT_LVB)
 504                 lksb->flags &= ~DLM_LKSB_PUT_LVB;
 505
 506         dlm_lockres_calc_usage(dlm, res);
 507         dlm_kick_thread(dlm, res);
 508
 509 not_found:
 510         if (!found)
 511                 mlog(ML_ERROR, "failed to find lock to unlock! "
 512                                "cookie=%u:%llu\n",
 513                      dlm_get_lock_cookie_node(be64_to_cpu(unlock->cookie)),
 514                      dlm_get_lock_cookie_seq(be64_to_cpu(unlock->cookie)));
 515         else
 516                 dlm_lock_put(lock);
 517
 518 leave:
 519         if (res)
 520                 dlm_lockres_put(res);
 521
 522         dlm_put(dlm);
 523
 524         return status;
 525 }
 526
 527
 528 static enum dlm_status dlm_get_cancel_actions(struct dlm_ctxt *dlm,
 529                                               struct dlm_lock_resource *res,
 530                                               struct dlm_lock *lock,
 531                                               struct dlm_lockstatus *lksb,
 532                                               int *actions)
 533 {
 534         enum dlm_status status;
 535
 536         if (dlm_lock_on_list(&res->blocked, lock)) {
 537                 /* cancel this outright */
 538                 status = DLM_NORMAL;
 539                 *actions = (DLM_UNLOCK_CALL_AST |
 540                             DLM_UNLOCK_REMOVE_LOCK);
 541         } else if (dlm_lock_on_list(&res->converting, lock)) {
 542                 /* cancel the request, put back on granted */
 543                 status = DLM_NORMAL;
 544                 *actions = (DLM_UNLOCK_CALL_AST |
 545                             DLM_UNLOCK_REMOVE_LOCK |
 546                             DLM_UNLOCK_REGRANT_LOCK |
 547                             DLM_UNLOCK_CLEAR_CONVERT_TYPE);
 548         } else if (dlm_lock_on_list(&res->granted, lock)) {
 549                 /* too late, already granted. */
 550                 status = DLM_CANCELGRANT;
 551                 *actions = DLM_UNLOCK_CALL_AST;
 552         } else {
 553                 mlog(ML_ERROR, "lock to cancel is not on any list!\n");
 554                 status = DLM_IVLOCKID;
 555                 *actions = 0;
 556         }
 557         return status;
 558 }
 559
 560 static enum dlm_status dlm_get_unlock_actions(struct dlm_ctxt *dlm,
 561                                               struct dlm_lock_resource *res,
 562                                               struct dlm_lock *lock,
 563                                               struct dlm_lockstatus *lksb,
 564                                               int *actions)
 565 {
 566         enum dlm_status status;
 567
 568         /* unlock request */
 569         if (!dlm_lock_on_list(&res->granted, lock)) {
 570                 status = DLM_DENIED;
 571                 dlm_error(status);
 572                 *actions = 0;
 573         } else {
 574                 /* unlock granted lock */
 575                 status = DLM_NORMAL;
 576                 *actions = (DLM_UNLOCK_FREE_LOCK |
 577                             DLM_UNLOCK_CALL_AST |
 578                             DLM_UNLOCK_REMOVE_LOCK);
 579         }
 580         return status;
 581 }
 582
 583 /* there seems to be no point in doing this async
 584  * since (even for the remote case) there is really
 585  * no work to queue up... so just do it and fire the
 586  * unlockast by hand when done... */
 587 enum dlm_status dlmunlock(struct dlm_ctxt *dlm, struct dlm_lockstatus *lksb,
 588                           int flags, dlm_astunlockfunc_t *unlockast, void *data)
 589 {
 590         enum dlm_status status;
 591         struct dlm_lock_resource *res;
 592         struct dlm_lock *lock = NULL;
 593         int call_ast, is_master;
 594
 595         if (!lksb) {
 596                 dlm_error(DLM_BADARGS);
 597                 return DLM_BADARGS;
 598         }
 599
 600         if (flags & ~(LKM_CANCEL | LKM_VALBLK | LKM_INVVALBLK)) {
 601                 dlm_error(DLM_BADPARAM);
 602                 return DLM_BADPARAM;
 603         }
 604
 605         if ((flags & (LKM_VALBLK | LKM_CANCEL)) == (LKM_VALBLK | LKM_CANCEL)) {
 606                 mlog(0, "VALBLK given with CANCEL: ignoring VALBLK\n");
 607                 flags &= ~LKM_VALBLK;
 608         }
 609
 610         if (!lksb->lockid || !lksb->lockid->lockres) {
 611                 dlm_error(DLM_BADPARAM);
 612                 return DLM_BADPARAM;
 613         }
 614
 615         lock = lksb->lockid;
 616         BUG_ON(!lock);
 617         dlm_lock_get(lock);
 618
 619         res = lock->lockres;
 620         BUG_ON(!res);
 621         dlm_lockres_get(res);
 622 retry:
 623         call_ast = 0;
 624         /* need to retry up here because owner may have changed */
 625         mlog(0, "lock=%p res=%p\n", lock, res);
 626
 627         spin_lock(&res->spinlock);
 628         is_master = (res->owner == dlm->node_num);
 629         if (flags & LKM_VALBLK && lock->ml.type != LKM_EXMODE)
 630                 flags &= ~LKM_VALBLK;
 631         spin_unlock(&res->spinlock);
 632
 633         if (is_master) {
 634                 status = dlmunlock_master(dlm, res, lock, lksb, flags,
 635                                           &call_ast);
 636                 mlog(0, "done calling dlmunlock_master: returned %d, "
 637                      "call_ast is %d\n", status, call_ast);
 638         } else {
 639                 status = dlmunlock_remote(dlm, res, lock, lksb, flags,
 640                                           &call_ast);
 641                 mlog(0, "done calling dlmunlock_remote: returned %d, "
 642                      "call_ast is %d\n", status, call_ast);
 643         }
 644
 645         if (status == DLM_RECOVERING ||
 646             status == DLM_MIGRATING ||
 647             status == DLM_FORWARD ||
 648             status == DLM_NOLOCKMGR) {
 649
 650                 /* We want to go away for a tiny bit to allow recovery
 651                  * / migration to complete on this resource. I don't
 652                  * know of any wait queue we could sleep on as this
 653                  * may be happening on another node. Perhaps the
 654                  * proper solution is to queue up requests on the
 655                  * other end? */
 656
 657                 /* do we want to yield(); ?? */
 658                 msleep(50);
 659
 660                 mlog(0, "retrying unlock due to pending recovery/"
 661                      "migration/in-progress/reconnect\n");
 662                 goto retry;
 663         }
 664
 665         if (call_ast) {
 666                 mlog(0, "calling unlockast(%p, %d)\n", data, status);
 667                 if (is_master) {
 668                         /* it is possible that there is one last bast
 669                          * pending.  make sure it is flushed, then
 670                          * call the unlockast.
 671                          * not an issue if this is a mastered remotely,
 672                          * since this lock has been removed from the
 673                          * lockres queues and cannot be found. */
 674                         dlm_kick_thread(dlm, NULL);
 675                         wait_event(dlm->ast_wq,
 676                                    dlm_lock_basts_flushed(dlm, lock));
 677                 }
 678                 (*unlockast)(data, status);
 679         }
 680
 681         if (status == DLM_CANCELGRANT)
 682                 status = DLM_NORMAL;
 683
 684         if (status == DLM_NORMAL) {
 685                 mlog(0, "kicking the thread\n");
 686                 dlm_kick_thread(dlm, res);
 687         } else
 688                 dlm_error(status);
 689
 690         dlm_lockres_calc_usage(dlm, res);
 691         dlm_lockres_put(res);
 692         dlm_lock_put(lock);
 693
 694         mlog(0, "returning status=%d!\n", status);
 695         return status;
 696 }
 697 EXPORT_SYMBOL_GPL(dlmunlock);
 698