fs/ocfs2/dlm/dlmunlock.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * dlmunlock.c
   4  *
   5  * underlying calls for unlocking locks
   6  *
   7  * Copyright (C) 2004 Oracle.  All rights reserved.
   8  */
   9
  10
  11 #include <linux/module.h>
  12 #include <linux/fs.h>
  13 #include <linux/types.h>
  14 #include <linux/highmem.h>
  15 #include <linux/init.h>
  16 #include <linux/sysctl.h>
  17 #include <linux/random.h>
  18 #include <linux/blkdev.h>
  19 #include <linux/socket.h>
  20 #include <linux/inet.h>
  21 #include <linux/spinlock.h>
  22 #include <linux/delay.h>
  23
  24 #include "../cluster/heartbeat.h"
  25 #include "../cluster/nodemanager.h"
  26 #include "../cluster/tcp.h"
  27
  28 #include "dlmapi.h"
  29 #include "dlmcommon.h"
  30
  31 #define MLOG_MASK_PREFIX ML_DLM
  32 #include "../cluster/masklog.h"
  33
  34 #define DLM_UNLOCK_FREE_LOCK           0x00000001
  35 #define DLM_UNLOCK_CALL_AST            0x00000002
  36 #define DLM_UNLOCK_REMOVE_LOCK         0x00000004
  37 #define DLM_UNLOCK_REGRANT_LOCK        0x00000008
  38 #define DLM_UNLOCK_CLEAR_CONVERT_TYPE  0x00000010
  39
  40
  41 static enum dlm_status dlm_get_cancel_actions(struct dlm_ctxt *dlm,
  42                                               struct dlm_lock_resource *res,
  43                                               struct dlm_lock *lock,
  44                                               struct dlm_lockstatus *lksb,
  45                                               int *actions);
  46 static enum dlm_status dlm_get_unlock_actions(struct dlm_ctxt *dlm,
  47                                               struct dlm_lock_resource *res,
  48                                               struct dlm_lock *lock,
  49                                               struct dlm_lockstatus *lksb,
  50                                               int *actions);
  51
  52 static enum dlm_status dlm_send_remote_unlock_request(struct dlm_ctxt *dlm,
  53                                                  struct dlm_lock_resource *res,
  54                                                  struct dlm_lock *lock,
  55                                                  struct dlm_lockstatus *lksb,
  56                                                  int flags,
  57                                                  u8 owner);
  58
  59
  60 /*
  61  * according to the spec:
  62  * http://opendlm.sourceforge.net/cvsmirror/opendlm/docs/dlmbook_final.pdf
  63  *
  64  *  flags & LKM_CANCEL != 0: must be converting or blocked
  65  *  flags & LKM_CANCEL == 0: must be granted
  66  *
  67  * So to unlock a converting lock, you must first cancel the
  68  * convert (passing LKM_CANCEL in flags), then call the unlock
  69  * again (with no LKM_CANCEL in flags).
  70  */
  71
  72
  73 /*
  74  * locking:
  75  *   caller needs:  none
  76  *   taken:         res->spinlock and lock->spinlock taken and dropped
  77  *   held on exit:  none
  78  * returns: DLM_NORMAL, DLM_NOLOCKMGR, status from network
  79  * all callers should have taken an extra ref on lock coming in
  80  */
  81 static enum dlm_status dlmunlock_common(struct dlm_ctxt *dlm,
  82                                         struct dlm_lock_resource *res,
  83                                         struct dlm_lock *lock,
  84                                         struct dlm_lockstatus *lksb,
  85                                         int flags, int *call_ast,
  86                                         int master_node)
  87 {
  88         enum dlm_status status;
  89         int actions = 0;
  90         int in_use;
  91         u8 owner;
  92         int recovery_wait = 0;
  93
  94         mlog(0, "master_node = %d, valblk = %d\n", master_node,
  95              flags & LKM_VALBLK);
  96
  97         if (master_node)
  98                 BUG_ON(res->owner != dlm->node_num);
  99         else
 100                 BUG_ON(res->owner == dlm->node_num);
 101
 102         spin_lock(&dlm->ast_lock);
 103         /* We want to be sure that we're not freeing a lock
 104          * that still has AST's pending... */
 105         in_use = !list_empty(&lock->ast_list);
 106         spin_unlock(&dlm->ast_lock);
 107         if (in_use && !(flags & LKM_CANCEL)) {
 108                mlog(ML_ERROR, "lockres %.*s: Someone is calling dlmunlock "
 109                     "while waiting for an ast!", res->lockname.len,
 110                     res->lockname.name);
 111                 return DLM_BADPARAM;
 112         }
 113
 114         spin_lock(&res->spinlock);
 115         if (res->state & DLM_LOCK_RES_IN_PROGRESS) {
 116                 if (master_node && !(flags & LKM_CANCEL)) {
 117                         mlog(ML_ERROR, "lockres in progress!\n");
 118                         spin_unlock(&res->spinlock);
 119                         return DLM_FORWARD;
 120                 }
 121                 /* ok for this to sleep if not in a network handler */
 122                 __dlm_wait_on_lockres(res);
 123                 res->state |= DLM_LOCK_RES_IN_PROGRESS;
 124         }
 125         spin_lock(&lock->spinlock);
 126
 127         if (res->state & DLM_LOCK_RES_RECOVERING) {
 128                 status = DLM_RECOVERING;
 129                 goto leave;
 130         }
 131
 132         if (res->state & DLM_LOCK_RES_MIGRATING) {
 133                 status = DLM_MIGRATING;
 134                 goto leave;
 135         }
 136
 137         /* see above for what the spec says about
 138          * LKM_CANCEL and the lock queue state */
 139         if (flags & LKM_CANCEL)
 140                 status = dlm_get_cancel_actions(dlm, res, lock, lksb, &actions);
 141         else
 142                 status = dlm_get_unlock_actions(dlm, res, lock, lksb, &actions);
 143
 144         if (status != DLM_NORMAL && (status != DLM_CANCELGRANT || !master_node))
 145                 goto leave;
 146
 147         /* By now this has been masked out of cancel requests. */
 148         if (flags & LKM_VALBLK) {
 149                 /* make the final update to the lvb */
 150                 if (master_node)
 151                         memcpy(res->lvb, lksb->lvb, DLM_LVB_LEN);
 152                 else
 153                         flags |= LKM_PUT_LVB; /* let the send function
 154                                                * handle it. */
 155         }
 156
 157         if (!master_node) {
 158                 owner = res->owner;
 159                 /* drop locks and send message */
 160                 if (flags & LKM_CANCEL)
 161                         lock->cancel_pending = 1;
 162                 else
 163                         lock->unlock_pending = 1;
 164                 spin_unlock(&lock->spinlock);
 165                 spin_unlock(&res->spinlock);
 166                 status = dlm_send_remote_unlock_request(dlm, res, lock, lksb,
 167                                                         flags, owner);
 168                 spin_lock(&res->spinlock);
 169                 spin_lock(&lock->spinlock);
 170                 /* if the master told us the lock was already granted,
 171                  * let the ast handle all of these actions */
 172                 if (status == DLM_CANCELGRANT) {
 173                         actions &= ~(DLM_UNLOCK_REMOVE_LOCK|
 174                                      DLM_UNLOCK_REGRANT_LOCK|
 175                                      DLM_UNLOCK_CLEAR_CONVERT_TYPE);
 176                 } else if (status == DLM_RECOVERING ||
 177                            status == DLM_MIGRATING ||
 178                            status == DLM_FORWARD ||
 179                            status == DLM_NOLOCKMGR
 180                            ) {
 181                         /* must clear the actions because this unlock
 182                          * is about to be retried.  cannot free or do
 183                          * any list manipulation. */
 184                         mlog(0, "%s:%.*s: clearing actions, %s\n",
 185                              dlm->name, res->lockname.len,
 186                              res->lockname.name,
 187                              status==DLM_RECOVERING?"recovering":
 188                              (status==DLM_MIGRATING?"migrating":
 189                                 (status == DLM_FORWARD ? "forward" :
 190                                                 "nolockmanager")));
 191                         actions = 0;
 192                 }
 193                 if (flags & LKM_CANCEL)
 194                         lock->cancel_pending = 0;
 195                 else {
 196                         if (!lock->unlock_pending)
 197                                 recovery_wait = 1;
 198                         else
 199                                 lock->unlock_pending = 0;
 200                 }
 201         }
 202
 203         /* get an extra ref on lock.  if we are just switching
 204          * lists here, we dont want the lock to go away. */
 205         dlm_lock_get(lock);
 206
 207         if (actions & DLM_UNLOCK_REMOVE_LOCK) {
 208                 list_del_init(&lock->list);
 209                 dlm_lock_put(lock);
 210         }
 211         if (actions & DLM_UNLOCK_REGRANT_LOCK) {
 212                 dlm_lock_get(lock);
 213                 list_add_tail(&lock->list, &res->granted);
 214         }
 215         if (actions & DLM_UNLOCK_CLEAR_CONVERT_TYPE) {
 216                 mlog(0, "clearing convert_type at %smaster node\n",
 217                      master_node ? "" : "non-");
 218                 lock->ml.convert_type = LKM_IVMODE;
 219         }
 220
 221         /* remove the extra ref on lock */
 222         dlm_lock_put(lock);
 223
 224 leave:
 225         res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
 226         if (!dlm_lock_on_list(&res->converting, lock))
 227                 BUG_ON(lock->ml.convert_type != LKM_IVMODE);
 228         else
 229                 BUG_ON(lock->ml.convert_type == LKM_IVMODE);
 230         spin_unlock(&lock->spinlock);
 231         spin_unlock(&res->spinlock);
 232         wake_up(&res->wq);
 233
 234         if (recovery_wait) {
 235                 spin_lock(&res->spinlock);
 236                 /* Unlock request will directly succeed after owner dies,
 237                  * and the lock is already removed from grant list. We have to
 238                  * wait for RECOVERING done or we miss the chance to purge it
 239                  * since the removement is much faster than RECOVERING proc.
 240                  */
 241                 __dlm_wait_on_lockres_flags(res, DLM_LOCK_RES_RECOVERING);
 242                 spin_unlock(&res->spinlock);
 243         }
 244
 245         /* let the caller's final dlm_lock_put handle the actual kfree */
 246         if (actions & DLM_UNLOCK_FREE_LOCK) {
 247                 /* this should always be coupled with list removal */
 248                 BUG_ON(!(actions & DLM_UNLOCK_REMOVE_LOCK));
 249                 mlog(0, "lock %u:%llu should be gone now! refs=%d\n",
 250                      dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
 251                      dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
 252                      kref_read(&lock->lock_refs)-1);
 253                 dlm_lock_put(lock);
 254         }
 255         if (actions & DLM_UNLOCK_CALL_AST)
 256                 *call_ast = 1;
 257
 258         /* if cancel or unlock succeeded, lvb work is done */
 259         if (status == DLM_NORMAL)
 260                 lksb->flags &= ~(DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB);
 261
 262         return status;
 263 }
 264
 265 void dlm_commit_pending_unlock(struct dlm_lock_resource *res,
 266                                struct dlm_lock *lock)
 267 {
 268         /* leave DLM_LKSB_PUT_LVB on the lksb so any final
 269          * update of the lvb will be sent to the new master */
 270         list_del_init(&lock->list);
 271 }
 272
 273 void dlm_commit_pending_cancel(struct dlm_lock_resource *res,
 274                                struct dlm_lock *lock)
 275 {
 276         list_move_tail(&lock->list, &res->granted);
 277         lock->ml.convert_type = LKM_IVMODE;
 278 }
 279
 280
 281 static inline enum dlm_status dlmunlock_master(struct dlm_ctxt *dlm,
 282                                           struct dlm_lock_resource *res,
 283                                           struct dlm_lock *lock,
 284                                           struct dlm_lockstatus *lksb,
 285                                           int flags,
 286                                           int *call_ast)
 287 {
 288         return dlmunlock_common(dlm, res, lock, lksb, flags, call_ast, 1);
 289 }
 290
 291 static inline enum dlm_status dlmunlock_remote(struct dlm_ctxt *dlm,
 292                                           struct dlm_lock_resource *res,
 293                                           struct dlm_lock *lock,
 294                                           struct dlm_lockstatus *lksb,
 295                                           int flags, int *call_ast)
 296 {
 297         return dlmunlock_common(dlm, res, lock, lksb, flags, call_ast, 0);
 298 }
 299
 300 /*
 301  * locking:
 302  *   caller needs:  none
 303  *   taken:         none
 304  *   held on exit:  none
 305  * returns: DLM_NORMAL, DLM_NOLOCKMGR, status from network
 306  */
 307 static enum dlm_status dlm_send_remote_unlock_request(struct dlm_ctxt *dlm,
 308                                                  struct dlm_lock_resource *res,
 309                                                  struct dlm_lock *lock,
 310                                                  struct dlm_lockstatus *lksb,
 311                                                  int flags,
 312                                                  u8 owner)
 313 {
 314         struct dlm_unlock_lock unlock;
 315         int tmpret;
 316         enum dlm_status ret;
 317         int status = 0;
 318         struct kvec vec[2];
 319         size_t veclen = 1;
 320
 321         mlog(0, "%.*s\n", res->lockname.len, res->lockname.name);
 322
 323         if (owner == dlm->node_num) {
 324                 /* ended up trying to contact ourself.  this means
 325                  * that the lockres had been remote but became local
 326                  * via a migration.  just retry it, now as local */
 327                 mlog(0, "%s:%.*s: this node became the master due to a "
 328                      "migration, re-evaluate now\n", dlm->name,
 329                      res->lockname.len, res->lockname.name);
 330                 return DLM_FORWARD;
 331         }
 332
 333         memset(&unlock, 0, sizeof(unlock));
 334         unlock.node_idx = dlm->node_num;
 335         unlock.flags = cpu_to_be32(flags);
 336         unlock.cookie = lock->ml.cookie;
 337         unlock.namelen = res->lockname.len;
 338         memcpy(unlock.name, res->lockname.name, unlock.namelen);
 339
 340         vec[0].iov_len = sizeof(struct dlm_unlock_lock);
 341         vec[0].iov_base = &unlock;
 342
 343         if (flags & LKM_PUT_LVB) {
 344                 /* extra data to send if we are updating lvb */
 345                 vec[1].iov_len = DLM_LVB_LEN;
 346                 vec[1].iov_base = lock->lksb->lvb;
 347                 veclen++;
 348         }
 349
 350         tmpret = o2net_send_message_vec(DLM_UNLOCK_LOCK_MSG, dlm->key,
 351                                         vec, veclen, owner, &status);
 352         if (tmpret >= 0) {
 353                 // successfully sent and received
 354                 if (status == DLM_FORWARD)
 355                         mlog(0, "master was in-progress.  retry\n");
 356                 ret = status;
 357         } else {
 358                 mlog(ML_ERROR, "Error %d when sending message %u (key 0x%x) to "
 359                      "node %u\n", tmpret, DLM_UNLOCK_LOCK_MSG, dlm->key, owner);
 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                         if (dlm_is_node_dead(dlm, owner))
 369                                 ret = DLM_NORMAL;
 370                         else
 371                                 ret = DLM_NOLOCKMGR;
 372                 } else {
 373                         /* something bad.  this will BUG in ocfs2 */
 374                         ret = dlm_err_to_dlm_status(tmpret);
 375                 }
 376         }
 377
 378         return ret;
 379 }
 380
 381 /*
 382  * locking:
 383  *   caller needs:  none
 384  *   taken:         takes and drops res->spinlock
 385  *   held on exit:  none
 386  * returns: DLM_NORMAL, DLM_BADARGS, DLM_IVLOCKID,
 387  *          return value from dlmunlock_master
 388  */
 389 int dlm_unlock_lock_handler(struct o2net_msg *msg, u32 len, void *data,
 390                             void **ret_data)
 391 {
 392         struct dlm_ctxt *dlm = data;
 393         struct dlm_unlock_lock *unlock = (struct dlm_unlock_lock *)msg->buf;
 394         struct dlm_lock_resource *res = NULL;
 395         struct dlm_lock *lock = NULL;
 396         enum dlm_status status = DLM_NORMAL;
 397         int found = 0, i;
 398         struct dlm_lockstatus *lksb = NULL;
 399         int ignore;
 400         u32 flags;
 401         struct list_head *queue;
 402
 403         flags = be32_to_cpu(unlock->flags);
 404
 405         if (flags & LKM_GET_LVB) {
 406                 mlog(ML_ERROR, "bad args!  GET_LVB specified on unlock!\n");
 407                 return DLM_BADARGS;
 408         }
 409
 410         if ((flags & (LKM_PUT_LVB|LKM_CANCEL)) == (LKM_PUT_LVB|LKM_CANCEL)) {
 411                 mlog(ML_ERROR, "bad args!  cannot modify lvb on a CANCEL "
 412                      "request!\n");
 413                 return DLM_BADARGS;
 414         }
 415
 416         if (unlock->namelen > DLM_LOCKID_NAME_MAX) {
 417                 mlog(ML_ERROR, "Invalid name length in unlock handler!\n");
 418                 return DLM_IVBUFLEN;
 419         }
 420
 421         if (!dlm_grab(dlm))
 422                 return DLM_FORWARD;
 423
 424         mlog_bug_on_msg(!dlm_domain_fully_joined(dlm),
 425                         "Domain %s not fully joined!\n", dlm->name);
 426
 427         mlog(0, "lvb: %s\n", flags & LKM_PUT_LVB ? "put lvb" : "none");
 428
 429         res = dlm_lookup_lockres(dlm, unlock->name, unlock->namelen);
 430         if (!res) {
 431                 /* We assume here that a no lock resource simply means
 432                  * it was migrated away and destroyed before the other
 433                  * node could detect it. */
 434                 mlog(0, "returning DLM_FORWARD -- res no longer exists\n");
 435                 status = DLM_FORWARD;
 436                 goto not_found;
 437         }
 438
 439         queue=&res->granted;
 440         found = 0;
 441         spin_lock(&res->spinlock);
 442         if (res->state & DLM_LOCK_RES_RECOVERING) {
 443                 spin_unlock(&res->spinlock);
 444                 mlog(0, "returning DLM_RECOVERING\n");
 445                 status = DLM_RECOVERING;
 446                 goto leave;
 447         }
 448
 449         if (res->state & DLM_LOCK_RES_MIGRATING) {
 450                 spin_unlock(&res->spinlock);
 451                 mlog(0, "returning DLM_MIGRATING\n");
 452                 status = DLM_MIGRATING;
 453                 goto leave;
 454         }
 455
 456         if (res->owner != dlm->node_num) {
 457                 spin_unlock(&res->spinlock);
 458                 mlog(0, "returning DLM_FORWARD -- not master\n");
 459                 status = DLM_FORWARD;
 460                 goto leave;
 461         }
 462
 463         for (i=0; i<3; i++) {
 464                 list_for_each_entry(lock, queue, list) {
 465                         if (lock->ml.cookie == unlock->cookie &&
 466                             lock->ml.node == unlock->node_idx) {
 467                                 dlm_lock_get(lock);
 468                                 found = 1;
 469                                 break;
 470                         }
 471                 }
 472                 if (found)
 473                         break;
 474                 /* scan granted -> converting -> blocked queues */
 475                 queue++;
 476         }
 477         spin_unlock(&res->spinlock);
 478         if (!found) {
 479                 status = DLM_IVLOCKID;
 480                 goto not_found;
 481         }
 482
 483         /* lock was found on queue */
 484         lksb = lock->lksb;
 485         if (flags & (LKM_VALBLK|LKM_PUT_LVB) &&
 486             lock->ml.type != LKM_EXMODE)
 487                 flags &= ~(LKM_VALBLK|LKM_PUT_LVB);
 488
 489         /* unlockast only called on originating node */
 490         if (flags & LKM_PUT_LVB) {
 491                 lksb->flags |= DLM_LKSB_PUT_LVB;
 492                 memcpy(&lksb->lvb[0], &unlock->lvb[0], DLM_LVB_LEN);
 493         }
 494
 495         /* if this is in-progress, propagate the DLM_FORWARD
 496          * all the way back out */
 497         status = dlmunlock_master(dlm, res, lock, lksb, flags, &ignore);
 498         if (status == DLM_FORWARD)
 499                 mlog(0, "lockres is in progress\n");
 500
 501         if (flags & LKM_PUT_LVB)
 502                 lksb->flags &= ~DLM_LKSB_PUT_LVB;
 503
 504         dlm_lockres_calc_usage(dlm, res);
 505         dlm_kick_thread(dlm, res);
 506
 507 not_found:
 508         if (!found)
 509                 mlog(ML_ERROR, "failed to find lock to unlock! "
 510                                "cookie=%u:%llu\n",
 511                      dlm_get_lock_cookie_node(be64_to_cpu(unlock->cookie)),
 512                      dlm_get_lock_cookie_seq(be64_to_cpu(unlock->cookie)));
 513         else
 514                 dlm_lock_put(lock);
 515
 516 leave:
 517         if (res)
 518                 dlm_lockres_put(res);
 519
 520         dlm_put(dlm);
 521
 522         return status;
 523 }
 524
 525
 526 static enum dlm_status dlm_get_cancel_actions(struct dlm_ctxt *dlm,
 527                                               struct dlm_lock_resource *res,
 528                                               struct dlm_lock *lock,
 529                                               struct dlm_lockstatus *lksb,
 530                                               int *actions)
 531 {
 532         enum dlm_status status;
 533
 534         if (dlm_lock_on_list(&res->blocked, lock)) {
 535                 /* cancel this outright */
 536                 status = DLM_NORMAL;
 537                 *actions = (DLM_UNLOCK_CALL_AST |
 538                             DLM_UNLOCK_REMOVE_LOCK);
 539         } else if (dlm_lock_on_list(&res->converting, lock)) {
 540                 /* cancel the request, put back on granted */
 541                 status = DLM_NORMAL;
 542                 *actions = (DLM_UNLOCK_CALL_AST |
 543                             DLM_UNLOCK_REMOVE_LOCK |
 544                             DLM_UNLOCK_REGRANT_LOCK |
 545                             DLM_UNLOCK_CLEAR_CONVERT_TYPE);
 546         } else if (dlm_lock_on_list(&res->granted, lock)) {
 547                 /* too late, already granted. */
 548                 status = DLM_CANCELGRANT;
 549                 *actions = DLM_UNLOCK_CALL_AST;
 550         } else {
 551                 mlog(ML_ERROR, "lock to cancel is not on any list!\n");
 552                 status = DLM_IVLOCKID;
 553                 *actions = 0;
 554         }
 555         return status;
 556 }
 557
 558 static enum dlm_status dlm_get_unlock_actions(struct dlm_ctxt *dlm,
 559                                               struct dlm_lock_resource *res,
 560                                               struct dlm_lock *lock,
 561                                               struct dlm_lockstatus *lksb,
 562                                               int *actions)
 563 {
 564         enum dlm_status status;
 565
 566         /* unlock request */
 567         if (!dlm_lock_on_list(&res->granted, lock)) {
 568                 status = DLM_DENIED;
 569                 dlm_error(status);
 570                 *actions = 0;
 571         } else {
 572                 /* unlock granted lock */
 573                 status = DLM_NORMAL;
 574                 *actions = (DLM_UNLOCK_FREE_LOCK |
 575                             DLM_UNLOCK_CALL_AST |
 576                             DLM_UNLOCK_REMOVE_LOCK);
 577         }
 578         return status;
 579 }
 580
 581 /* there seems to be no point in doing this async
 582  * since (even for the remote case) there is really
 583  * no work to queue up... so just do it and fire the
 584  * unlockast by hand when done... */
 585 enum dlm_status dlmunlock(struct dlm_ctxt *dlm, struct dlm_lockstatus *lksb,
 586                           int flags, dlm_astunlockfunc_t *unlockast, void *data)
 587 {
 588         enum dlm_status status;
 589         struct dlm_lock_resource *res;
 590         struct dlm_lock *lock = NULL;
 591         int call_ast, is_master;
 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             status == DLM_NOLOCKMGR) {
 647
 648                 /* We want to go away for a tiny bit to allow recovery
 649                  * / migration to complete on this resource. I don't
 650                  * know of any wait queue we could sleep on as this
 651                  * may be happening on another node. Perhaps the
 652                  * proper solution is to queue up requests on the
 653                  * other end? */
 654
 655                 /* do we want to yield(); ?? */
 656                 msleep(50);
 657
 658                 mlog(0, "retrying unlock due to pending recovery/"
 659                      "migration/in-progress/reconnect\n");
 660                 goto retry;
 661         }
 662
 663         if (call_ast) {
 664                 mlog(0, "calling unlockast(%p, %d)\n", data, status);
 665                 if (is_master) {
 666                         /* it is possible that there is one last bast
 667                          * pending.  make sure it is flushed, then
 668                          * call the unlockast.
 669                          * not an issue if this is a mastered remotely,
 670                          * since this lock has been removed from the
 671                          * lockres queues and cannot be found. */
 672                         dlm_kick_thread(dlm, NULL);
 673                         wait_event(dlm->ast_wq,
 674                                    dlm_lock_basts_flushed(dlm, lock));
 675                 }
 676                 (*unlockast)(data, status);
 677         }
 678
 679         if (status == DLM_CANCELGRANT)
 680                 status = DLM_NORMAL;
 681
 682         if (status == DLM_NORMAL) {
 683                 mlog(0, "kicking the thread\n");
 684                 dlm_kick_thread(dlm, res);
 685         } else
 686                 dlm_error(status);
 687
 688         dlm_lockres_calc_usage(dlm, res);
 689         dlm_lockres_put(res);
 690         dlm_lock_put(lock);
 691
 692         mlog(0, "returning status=%d!\n", status);
 693         return status;
 694 }
 695 EXPORT_SYMBOL_GPL(dlmunlock);
 696