fs/ocfs2/dlm/dlmunlock.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* -*- mode: c; c-basic-offset: 8; -*-
   3  * vim: noexpandtab sw=8 ts=8 sts=0:
   4  *
   5  * dlmunlock.c
   6  *
   7  * underlying calls for unlocking locks
   8  *
   9  * Copyright (C) 2004 Oracle.  All rights reserved.
  10  */
  11
  12
  13 #include <linux/module.h>
  14 #include <linux/fs.h>
  15 #include <linux/types.h>
  16 #include <linux/highmem.h>
  17 #include <linux/init.h>
  18 #include <linux/sysctl.h>
  19 #include <linux/random.h>
  20 #include <linux/blkdev.h>
  21 #include <linux/socket.h>
  22 #include <linux/inet.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/delay.h>
  25
  26 #include "cluster/heartbeat.h"
  27 #include "cluster/nodemanager.h"
  28 #include "cluster/tcp.h"
  29
  30 #include "dlmapi.h"
  31 #include "dlmcommon.h"
  32
  33 #define MLOG_MASK_PREFIX ML_DLM
  34 #include "cluster/masklog.h"
  35
  36 #define DLM_UNLOCK_FREE_LOCK           0x00000001
  37 #define DLM_UNLOCK_CALL_AST            0x00000002
  38 #define DLM_UNLOCK_REMOVE_LOCK         0x00000004
  39 #define DLM_UNLOCK_REGRANT_LOCK        0x00000008
  40 #define DLM_UNLOCK_CLEAR_CONVERT_TYPE  0x00000010
  41
  42
  43 static enum dlm_status dlm_get_cancel_actions(struct dlm_ctxt *dlm,
  44                                               struct dlm_lock_resource *res,
  45                                               struct dlm_lock *lock,
  46                                               struct dlm_lockstatus *lksb,
  47                                               int *actions);
  48 static enum dlm_status dlm_get_unlock_actions(struct dlm_ctxt *dlm,
  49                                               struct dlm_lock_resource *res,
  50                                               struct dlm_lock *lock,
  51                                               struct dlm_lockstatus *lksb,
  52                                               int *actions);
  53
  54 static enum dlm_status dlm_send_remote_unlock_request(struct dlm_ctxt *dlm,
  55                                                  struct dlm_lock_resource *res,
  56                                                  struct dlm_lock *lock,
  57                                                  struct dlm_lockstatus *lksb,
  58                                                  int flags,
  59                                                  u8 owner);
  60
  61
  62 /*
  63  * according to the spec:
  64  * http://opendlm.sourceforge.net/cvsmirror/opendlm/docs/dlmbook_final.pdf
  65  *
  66  *  flags & LKM_CANCEL != 0: must be converting or blocked
  67  *  flags & LKM_CANCEL == 0: must be granted
  68  *
  69  * So to unlock a converting lock, you must first cancel the
  70  * convert (passing LKM_CANCEL in flags), then call the unlock
  71  * again (with no LKM_CANCEL in flags).
  72  */
  73
  74
  75 /*
  76  * locking:
  77  *   caller needs:  none
  78  *   taken:         res->spinlock and lock->spinlock taken and dropped
  79  *   held on exit:  none
  80  * returns: DLM_NORMAL, DLM_NOLOCKMGR, status from network
  81  * all callers should have taken an extra ref on lock coming in
  82  */
  83 static enum dlm_status dlmunlock_common(struct dlm_ctxt *dlm,
  84                                         struct dlm_lock_resource *res,
  85                                         struct dlm_lock *lock,
  86                                         struct dlm_lockstatus *lksb,
  87                                         int flags, int *call_ast,
  88                                         int master_node)
  89 {
  90         enum dlm_status status;
  91         int actions = 0;
  92         int in_use;
  93         u8 owner;
  94
  95         mlog(0, "master_node = %d, valblk = %d\n", master_node,
  96              flags & LKM_VALBLK);
  97
  98         if (master_node)
  99                 BUG_ON(res->owner != dlm->node_num);
 100         else
 101                 BUG_ON(res->owner == dlm->node_num);
 102
 103         spin_lock(&dlm->ast_lock);
 104         /* We want to be sure that we're not freeing a lock
 105          * that still has AST's pending... */
 106         in_use = !list_empty(&lock->ast_list);
 107         spin_unlock(&dlm->ast_lock);
 108         if (in_use && !(flags & LKM_CANCEL)) {
 109                mlog(ML_ERROR, "lockres %.*s: Someone is calling dlmunlock "
 110                     "while waiting for an ast!", res->lockname.len,
 111                     res->lockname.name);
 112                 return DLM_BADPARAM;
 113         }
 114
 115         spin_lock(&res->spinlock);
 116         if (res->state & DLM_LOCK_RES_IN_PROGRESS) {
 117                 if (master_node && !(flags & LKM_CANCEL)) {
 118                         mlog(ML_ERROR, "lockres in progress!\n");
 119                         spin_unlock(&res->spinlock);
 120                         return DLM_FORWARD;
 121                 }
 122                 /* ok for this to sleep if not in a network handler */
 123                 __dlm_wait_on_lockres(res);
 124                 res->state |= DLM_LOCK_RES_IN_PROGRESS;
 125         }
 126         spin_lock(&lock->spinlock);
 127
 128         if (res->state & DLM_LOCK_RES_RECOVERING) {
 129                 status = DLM_RECOVERING;
 130                 goto leave;
 131         }
 132
 133         if (res->state & DLM_LOCK_RES_MIGRATING) {
 134                 status = DLM_MIGRATING;
 135                 goto leave;
 136         }
 137
 138         /* see above for what the spec says about
 139          * LKM_CANCEL and the lock queue state */
 140         if (flags & LKM_CANCEL)
 141                 status = dlm_get_cancel_actions(dlm, res, lock, lksb, &actions);
 142         else
 143                 status = dlm_get_unlock_actions(dlm, res, lock, lksb, &actions);
 144
 145         if (status != DLM_NORMAL && (status != DLM_CANCELGRANT || !master_node))
 146                 goto leave;
 147
 148         /* By now this has been masked out of cancel requests. */
 149         if (flags & LKM_VALBLK) {
 150                 /* make the final update to the lvb */
 151                 if (master_node)
 152                         memcpy(res->lvb, lksb->lvb, DLM_LVB_LEN);
 153                 else
 154                         flags |= LKM_PUT_LVB; /* let the send function
 155                                                * handle it. */
 156         }
 157
 158         if (!master_node) {
 159                 owner = res->owner;
 160                 /* drop locks and send message */
 161                 if (flags & LKM_CANCEL)
 162                         lock->cancel_pending = 1;
 163                 else
 164                         lock->unlock_pending = 1;
 165                 spin_unlock(&lock->spinlock);
 166                 spin_unlock(&res->spinlock);
 167                 status = dlm_send_remote_unlock_request(dlm, res, lock, lksb,
 168                                                         flags, owner);
 169                 spin_lock(&res->spinlock);
 170                 spin_lock(&lock->spinlock);
 171                 /* if the master told us the lock was already granted,
 172                  * let the ast handle all of these actions */
 173                 if (status == DLM_CANCELGRANT) {
 174                         actions &= ~(DLM_UNLOCK_REMOVE_LOCK|
 175                                      DLM_UNLOCK_REGRANT_LOCK|
 176                                      DLM_UNLOCK_CLEAR_CONVERT_TYPE);
 177                 } else if (status == DLM_RECOVERING ||
 178                            status == DLM_MIGRATING ||
 179                            status == DLM_FORWARD ||
 180                            status == DLM_NOLOCKMGR
 181                            ) {
 182                         /* must clear the actions because this unlock
 183                          * is about to be retried.  cannot free or do
 184                          * any list manipulation. */
 185                         mlog(0, "%s:%.*s: clearing actions, %s\n",
 186                              dlm->name, res->lockname.len,
 187                              res->lockname.name,
 188                              status==DLM_RECOVERING?"recovering":
 189                              (status==DLM_MIGRATING?"migrating":
 190                                 (status == DLM_FORWARD ? "forward" :
 191                                                 "nolockmanager")));
 192                         actions = 0;
 193                 }
 194                 if (flags & LKM_CANCEL)
 195                         lock->cancel_pending = 0;
 196                 else
 197                         lock->unlock_pending = 0;
 198
 199         }
 200
 201         /* get an extra ref on lock.  if we are just switching
 202          * lists here, we dont want the lock to go away. */
 203         dlm_lock_get(lock);
 204
 205         if (actions & DLM_UNLOCK_REMOVE_LOCK) {
 206                 list_del_init(&lock->list);
 207                 dlm_lock_put(lock);
 208         }
 209         if (actions & DLM_UNLOCK_REGRANT_LOCK) {
 210                 dlm_lock_get(lock);
 211                 list_add_tail(&lock->list, &res->granted);
 212         }
 213         if (actions & DLM_UNLOCK_CLEAR_CONVERT_TYPE) {
 214                 mlog(0, "clearing convert_type at %smaster node\n",
 215                      master_node ? "" : "non-");
 216                 lock->ml.convert_type = LKM_IVMODE;
 217         }
 218
 219         /* remove the extra ref on lock */
 220         dlm_lock_put(lock);
 221
 222 leave:
 223         res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
 224         if (!dlm_lock_on_list(&res->converting, lock))
 225                 BUG_ON(lock->ml.convert_type != LKM_IVMODE);
 226         else
 227                 BUG_ON(lock->ml.convert_type == LKM_IVMODE);
 228         spin_unlock(&lock->spinlock);
 229         spin_unlock(&res->spinlock);
 230         wake_up(&res->wq);
 231
 232         /* let the caller's final dlm_lock_put handle the actual kfree */
 233         if (actions & DLM_UNLOCK_FREE_LOCK) {
 234                 /* this should always be coupled with list removal */
 235                 BUG_ON(!(actions & DLM_UNLOCK_REMOVE_LOCK));
 236                 mlog(0, "lock %u:%llu should be gone now! refs=%d\n",
 237                      dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
 238                      dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
 239                      kref_read(&lock->lock_refs)-1);
 240                 dlm_lock_put(lock);
 241         }
 242         if (actions & DLM_UNLOCK_CALL_AST)
 243                 *call_ast = 1;
 244
 245         /* if cancel or unlock succeeded, lvb work is done */
 246         if (status == DLM_NORMAL)
 247                 lksb->flags &= ~(DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB);
 248
 249         return status;
 250 }
 251
 252 void dlm_commit_pending_unlock(struct dlm_lock_resource *res,
 253                                struct dlm_lock *lock)
 254 {
 255         /* leave DLM_LKSB_PUT_LVB on the lksb so any final
 256          * update of the lvb will be sent to the new master */
 257         list_del_init(&lock->list);
 258 }
 259
 260 void dlm_commit_pending_cancel(struct dlm_lock_resource *res,
 261                                struct dlm_lock *lock)
 262 {
 263         list_move_tail(&lock->list, &res->granted);
 264         lock->ml.convert_type = LKM_IVMODE;
 265 }
 266
 267
 268 static inline enum dlm_status dlmunlock_master(struct dlm_ctxt *dlm,
 269                                           struct dlm_lock_resource *res,
 270                                           struct dlm_lock *lock,
 271                                           struct dlm_lockstatus *lksb,
 272                                           int flags,
 273                                           int *call_ast)
 274 {
 275         return dlmunlock_common(dlm, res, lock, lksb, flags, call_ast, 1);
 276 }
 277
 278 static inline enum dlm_status dlmunlock_remote(struct dlm_ctxt *dlm,
 279                                           struct dlm_lock_resource *res,
 280                                           struct dlm_lock *lock,
 281                                           struct dlm_lockstatus *lksb,
 282                                           int flags, int *call_ast)
 283 {
 284         return dlmunlock_common(dlm, res, lock, lksb, flags, call_ast, 0);
 285 }
 286
 287 /*
 288  * locking:
 289  *   caller needs:  none
 290  *   taken:         none
 291  *   held on exit:  none
 292  * returns: DLM_NORMAL, DLM_NOLOCKMGR, status from network
 293  */
 294 static enum dlm_status dlm_send_remote_unlock_request(struct dlm_ctxt *dlm,
 295                                                  struct dlm_lock_resource *res,
 296                                                  struct dlm_lock *lock,
 297                                                  struct dlm_lockstatus *lksb,
 298                                                  int flags,
 299                                                  u8 owner)
 300 {
 301         struct dlm_unlock_lock unlock;
 302         int tmpret;
 303         enum dlm_status ret;
 304         int status = 0;
 305         struct kvec vec[2];
 306         size_t veclen = 1;
 307
 308         mlog(0, "%.*s\n", res->lockname.len, res->lockname.name);
 309
 310         if (owner == dlm->node_num) {
 311                 /* ended up trying to contact ourself.  this means
 312                  * that the lockres had been remote but became local
 313                  * via a migration.  just retry it, now as local */
 314                 mlog(0, "%s:%.*s: this node became the master due to a "
 315                      "migration, re-evaluate now\n", dlm->name,
 316                      res->lockname.len, res->lockname.name);
 317                 return DLM_FORWARD;
 318         }
 319
 320         memset(&unlock, 0, sizeof(unlock));
 321         unlock.node_idx = dlm->node_num;
 322         unlock.flags = cpu_to_be32(flags);
 323         unlock.cookie = lock->ml.cookie;
 324         unlock.namelen = res->lockname.len;
 325         memcpy(unlock.name, res->lockname.name, unlock.namelen);
 326
 327         vec[0].iov_len = sizeof(struct dlm_unlock_lock);
 328         vec[0].iov_base = &unlock;
 329
 330         if (flags & LKM_PUT_LVB) {
 331                 /* extra data to send if we are updating lvb */
 332                 vec[1].iov_len = DLM_LVB_LEN;
 333                 vec[1].iov_base = lock->lksb->lvb;
 334                 veclen++;
 335         }
 336
 337         tmpret = o2net_send_message_vec(DLM_UNLOCK_LOCK_MSG, dlm->key,
 338                                         vec, veclen, owner, &status);
 339         if (tmpret >= 0) {
 340                 // successfully sent and received
 341                 if (status == DLM_FORWARD)
 342                         mlog(0, "master was in-progress.  retry\n");
 343                 ret = status;
 344         } else {
 345                 mlog(ML_ERROR, "Error %d when sending message %u (key 0x%x) to "
 346                      "node %u\n", tmpret, DLM_UNLOCK_LOCK_MSG, dlm->key, owner);
 347                 if (dlm_is_host_down(tmpret)) {
 348                         /* NOTE: this seems strange, but it is what we want.
 349                          * when the master goes down during a cancel or
 350                          * unlock, the recovery code completes the operation
 351                          * as if the master had not died, then passes the
 352                          * updated state to the recovery master.  this thread
 353                          * just needs to finish out the operation and call
 354                          * the unlockast. */
 355                         if (dlm_is_node_dead(dlm, owner))
 356                                 ret = DLM_NORMAL;
 357                         else
 358                                 ret = DLM_NOLOCKMGR;
 359                 } else {
 360                         /* something bad.  this will BUG in ocfs2 */
 361                         ret = dlm_err_to_dlm_status(tmpret);
 362                 }
 363         }
 364
 365         return ret;
 366 }
 367
 368 /*
 369  * locking:
 370  *   caller needs:  none
 371  *   taken:         takes and drops res->spinlock
 372  *   held on exit:  none
 373  * returns: DLM_NORMAL, DLM_BADARGS, DLM_IVLOCKID,
 374  *          return value from dlmunlock_master
 375  */
 376 int dlm_unlock_lock_handler(struct o2net_msg *msg, u32 len, void *data,
 377                             void **ret_data)
 378 {
 379         struct dlm_ctxt *dlm = data;
 380         struct dlm_unlock_lock *unlock = (struct dlm_unlock_lock *)msg->buf;
 381         struct dlm_lock_resource *res = NULL;
 382         struct dlm_lock *lock = NULL;
 383         enum dlm_status status = DLM_NORMAL;
 384         int found = 0, i;
 385         struct dlm_lockstatus *lksb = NULL;
 386         int ignore;
 387         u32 flags;
 388         struct list_head *queue;
 389
 390         flags = be32_to_cpu(unlock->flags);
 391
 392         if (flags & LKM_GET_LVB) {
 393                 mlog(ML_ERROR, "bad args!  GET_LVB specified on unlock!\n");
 394                 return DLM_BADARGS;
 395         }
 396
 397         if ((flags & (LKM_PUT_LVB|LKM_CANCEL)) == (LKM_PUT_LVB|LKM_CANCEL)) {
 398                 mlog(ML_ERROR, "bad args!  cannot modify lvb on a CANCEL "
 399                      "request!\n");
 400                 return DLM_BADARGS;
 401         }
 402
 403         if (unlock->namelen > DLM_LOCKID_NAME_MAX) {
 404                 mlog(ML_ERROR, "Invalid name length in unlock handler!\n");
 405                 return DLM_IVBUFLEN;
 406         }
 407
 408         if (!dlm_grab(dlm))
 409                 return DLM_FORWARD;
 410
 411         mlog_bug_on_msg(!dlm_domain_fully_joined(dlm),
 412                         "Domain %s not fully joined!\n", dlm->name);
 413
 414         mlog(0, "lvb: %s\n", flags & LKM_PUT_LVB ? "put lvb" : "none");
 415
 416         res = dlm_lookup_lockres(dlm, unlock->name, unlock->namelen);
 417         if (!res) {
 418                 /* We assume here that a no lock resource simply means
 419                  * it was migrated away and destroyed before the other
 420                  * node could detect it. */
 421                 mlog(0, "returning DLM_FORWARD -- res no longer exists\n");
 422                 status = DLM_FORWARD;
 423                 goto not_found;
 424         }
 425
 426         queue=&res->granted;
 427         found = 0;
 428         spin_lock(&res->spinlock);
 429         if (res->state & DLM_LOCK_RES_RECOVERING) {
 430                 spin_unlock(&res->spinlock);
 431                 mlog(0, "returning DLM_RECOVERING\n");
 432                 status = DLM_RECOVERING;
 433                 goto leave;
 434         }
 435
 436         if (res->state & DLM_LOCK_RES_MIGRATING) {
 437                 spin_unlock(&res->spinlock);
 438                 mlog(0, "returning DLM_MIGRATING\n");
 439                 status = DLM_MIGRATING;
 440                 goto leave;
 441         }
 442
 443         if (res->owner != dlm->node_num) {
 444                 spin_unlock(&res->spinlock);
 445                 mlog(0, "returning DLM_FORWARD -- not master\n");
 446                 status = DLM_FORWARD;
 447                 goto leave;
 448         }
 449
 450         for (i=0; i<3; i++) {
 451                 list_for_each_entry(lock, queue, list) {
 452                         if (lock->ml.cookie == unlock->cookie &&
 453                             lock->ml.node == unlock->node_idx) {
 454                                 dlm_lock_get(lock);
 455                                 found = 1;
 456                                 break;
 457                         }
 458                 }
 459                 if (found)
 460                         break;
 461                 /* scan granted -> converting -> blocked queues */
 462                 queue++;
 463         }
 464         spin_unlock(&res->spinlock);
 465         if (!found) {
 466                 status = DLM_IVLOCKID;
 467                 goto not_found;
 468         }
 469
 470         /* lock was found on queue */
 471         lksb = lock->lksb;
 472         if (flags & (LKM_VALBLK|LKM_PUT_LVB) &&
 473             lock->ml.type != LKM_EXMODE)
 474                 flags &= ~(LKM_VALBLK|LKM_PUT_LVB);
 475
 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(be64_to_cpu(unlock->cookie)),
 499                      dlm_get_lock_cookie_seq(be64_to_cpu(unlock->cookie)));
 500         else
 501                 dlm_lock_put(lock);
 502
 503 leave:
 504         if (res)
 505                 dlm_lockres_put(res);
 506
 507         dlm_put(dlm);
 508
 509         return status;
 510 }
 511
 512
 513 static enum dlm_status dlm_get_cancel_actions(struct dlm_ctxt *dlm,
 514                                               struct dlm_lock_resource *res,
 515                                               struct dlm_lock *lock,
 516                                               struct dlm_lockstatus *lksb,
 517                                               int *actions)
 518 {
 519         enum dlm_status status;
 520
 521         if (dlm_lock_on_list(&res->blocked, lock)) {
 522                 /* cancel this outright */
 523                 status = DLM_NORMAL;
 524                 *actions = (DLM_UNLOCK_CALL_AST |
 525                             DLM_UNLOCK_REMOVE_LOCK);
 526         } else if (dlm_lock_on_list(&res->converting, lock)) {
 527                 /* cancel the request, put back on granted */
 528                 status = DLM_NORMAL;
 529                 *actions = (DLM_UNLOCK_CALL_AST |
 530                             DLM_UNLOCK_REMOVE_LOCK |
 531                             DLM_UNLOCK_REGRANT_LOCK |
 532                             DLM_UNLOCK_CLEAR_CONVERT_TYPE);
 533         } else if (dlm_lock_on_list(&res->granted, lock)) {
 534                 /* too late, already granted. */
 535                 status = DLM_CANCELGRANT;
 536                 *actions = DLM_UNLOCK_CALL_AST;
 537         } else {
 538                 mlog(ML_ERROR, "lock to cancel is not on any list!\n");
 539                 status = DLM_IVLOCKID;
 540                 *actions = 0;
 541         }
 542         return status;
 543 }
 544
 545 static enum dlm_status dlm_get_unlock_actions(struct dlm_ctxt *dlm,
 546                                               struct dlm_lock_resource *res,
 547                                               struct dlm_lock *lock,
 548                                               struct dlm_lockstatus *lksb,
 549                                               int *actions)
 550 {
 551         enum dlm_status status;
 552
 553         /* unlock request */
 554         if (!dlm_lock_on_list(&res->granted, lock)) {
 555                 status = DLM_DENIED;
 556                 dlm_error(status);
 557                 *actions = 0;
 558         } else {
 559                 /* unlock granted lock */
 560                 status = DLM_NORMAL;
 561                 *actions = (DLM_UNLOCK_FREE_LOCK |
 562                             DLM_UNLOCK_CALL_AST |
 563                             DLM_UNLOCK_REMOVE_LOCK);
 564         }
 565         return status;
 566 }
 567
 568 /* there seems to be no point in doing this async
 569  * since (even for the remote case) there is really
 570  * no work to queue up... so just do it and fire the
 571  * unlockast by hand when done... */
 572 enum dlm_status dlmunlock(struct dlm_ctxt *dlm, struct dlm_lockstatus *lksb,
 573                           int flags, dlm_astunlockfunc_t *unlockast, void *data)
 574 {
 575         enum dlm_status status;
 576         struct dlm_lock_resource *res;
 577         struct dlm_lock *lock = NULL;
 578         int call_ast, is_master;
 579
 580         if (!lksb) {
 581                 dlm_error(DLM_BADARGS);
 582                 return DLM_BADARGS;
 583         }
 584
 585         if (flags & ~(LKM_CANCEL | LKM_VALBLK | LKM_INVVALBLK)) {
 586                 dlm_error(DLM_BADPARAM);
 587                 return DLM_BADPARAM;
 588         }
 589
 590         if ((flags & (LKM_VALBLK | LKM_CANCEL)) == (LKM_VALBLK | LKM_CANCEL)) {
 591                 mlog(0, "VALBLK given with CANCEL: ignoring VALBLK\n");
 592                 flags &= ~LKM_VALBLK;
 593         }
 594
 595         if (!lksb->lockid || !lksb->lockid->lockres) {
 596                 dlm_error(DLM_BADPARAM);
 597                 return DLM_BADPARAM;
 598         }
 599
 600         lock = lksb->lockid;
 601         BUG_ON(!lock);
 602         dlm_lock_get(lock);
 603
 604         res = lock->lockres;
 605         BUG_ON(!res);
 606         dlm_lockres_get(res);
 607 retry:
 608         call_ast = 0;
 609         /* need to retry up here because owner may have changed */
 610         mlog(0, "lock=%p res=%p\n", lock, res);
 611
 612         spin_lock(&res->spinlock);
 613         is_master = (res->owner == dlm->node_num);
 614         if (flags & LKM_VALBLK && lock->ml.type != LKM_EXMODE)
 615                 flags &= ~LKM_VALBLK;
 616         spin_unlock(&res->spinlock);
 617
 618         if (is_master) {
 619                 status = dlmunlock_master(dlm, res, lock, lksb, flags,
 620                                           &call_ast);
 621                 mlog(0, "done calling dlmunlock_master: returned %d, "
 622                      "call_ast is %d\n", status, call_ast);
 623         } else {
 624                 status = dlmunlock_remote(dlm, res, lock, lksb, flags,
 625                                           &call_ast);
 626                 mlog(0, "done calling dlmunlock_remote: returned %d, "
 627                      "call_ast is %d\n", status, call_ast);
 628         }
 629
 630         if (status == DLM_RECOVERING ||
 631             status == DLM_MIGRATING ||
 632             status == DLM_FORWARD ||
 633             status == DLM_NOLOCKMGR) {
 634
 635                 /* We want to go away for a tiny bit to allow recovery
 636                  * / migration to complete on this resource. I don't
 637                  * know of any wait queue we could sleep on as this
 638                  * may be happening on another node. Perhaps the
 639                  * proper solution is to queue up requests on the
 640                  * other end? */
 641
 642                 /* do we want to yield(); ?? */
 643                 msleep(50);
 644
 645                 mlog(0, "retrying unlock due to pending recovery/"
 646                      "migration/in-progress/reconnect\n");
 647                 goto retry;
 648         }
 649
 650         if (call_ast) {
 651                 mlog(0, "calling unlockast(%p, %d)\n", data, status);
 652                 if (is_master) {
 653                         /* it is possible that there is one last bast
 654                          * pending.  make sure it is flushed, then
 655                          * call the unlockast.
 656                          * not an issue if this is a mastered remotely,
 657                          * since this lock has been removed from the
 658                          * lockres queues and cannot be found. */
 659                         dlm_kick_thread(dlm, NULL);
 660                         wait_event(dlm->ast_wq,
 661                                    dlm_lock_basts_flushed(dlm, lock));
 662                 }
 663                 (*unlockast)(data, status);
 664         }
 665
 666         if (status == DLM_CANCELGRANT)
 667                 status = DLM_NORMAL;
 668
 669         if (status == DLM_NORMAL) {
 670                 mlog(0, "kicking the thread\n");
 671                 dlm_kick_thread(dlm, res);
 672         } else
 673                 dlm_error(status);
 674
 675         dlm_lockres_calc_usage(dlm, res);
 676         dlm_lockres_put(res);
 677         dlm_lock_put(lock);
 678
 679         mlog(0, "returning status=%d!\n", status);
 680         return status;
 681 }
 682 EXPORT_SYMBOL_GPL(dlmunlock);
 683