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         int recovery_wait = 0;
 110
 111         mlog(0, "master_node = %d, valblk = %d\n", master_node,
 112              flags & LKM_VALBLK);
 113
 114         if (master_node)
 115                 BUG_ON(res->owner != dlm->node_num);
 116         else
 117                 BUG_ON(res->owner == dlm->node_num);
 118
 119         spin_lock(&dlm->ast_lock);
 120         /* We want to be sure that we're not freeing a lock
 121          * that still has AST's pending... */
 122         in_use = !list_empty(&lock->ast_list);
 123         spin_unlock(&dlm->ast_lock);
 124         if (in_use && !(flags & LKM_CANCEL)) {
 125                mlog(ML_ERROR, "lockres %.*s: Someone is calling dlmunlock "
 126                     "while waiting for an ast!", res->lockname.len,
 127                     res->lockname.name);
 128                 return DLM_BADPARAM;
 129         }
 130
 131         spin_lock(&res->spinlock);
 132         if (res->state & DLM_LOCK_RES_IN_PROGRESS) {
 133                 if (master_node && !(flags & LKM_CANCEL)) {
 134                         mlog(ML_ERROR, "lockres in progress!\n");
 135                         spin_unlock(&res->spinlock);
 136                         return DLM_FORWARD;
 137                 }
 138                 /* ok for this to sleep if not in a network handler */
 139                 __dlm_wait_on_lockres(res);
 140                 res->state |= DLM_LOCK_RES_IN_PROGRESS;
 141         }
 142         spin_lock(&lock->spinlock);
 143
 144         if (res->state & DLM_LOCK_RES_RECOVERING) {
 145                 status = DLM_RECOVERING;
 146                 goto leave;
 147         }
 148
 149         if (res->state & DLM_LOCK_RES_MIGRATING) {
 150                 status = DLM_MIGRATING;
 151                 goto leave;
 152         }
 153
 154         /* see above for what the spec says about
 155          * LKM_CANCEL and the lock queue state */
 156         if (flags & LKM_CANCEL)
 157                 status = dlm_get_cancel_actions(dlm, res, lock, lksb, &actions);
 158         else
 159                 status = dlm_get_unlock_actions(dlm, res, lock, lksb, &actions);
 160
 161         if (status != DLM_NORMAL && (status != DLM_CANCELGRANT || !master_node))
 162                 goto leave;
 163
 164         /* By now this has been masked out of cancel requests. */
 165         if (flags & LKM_VALBLK) {
 166                 /* make the final update to the lvb */
 167                 if (master_node)
 168                         memcpy(res->lvb, lksb->lvb, DLM_LVB_LEN);
 169                 else
 170                         flags |= LKM_PUT_LVB; /* let the send function
 171                                                * handle it. */
 172         }
 173
 174         if (!master_node) {
 175                 owner = res->owner;
 176                 /* drop locks and send message */
 177                 if (flags & LKM_CANCEL)
 178                         lock->cancel_pending = 1;
 179                 else
 180                         lock->unlock_pending = 1;
 181                 spin_unlock(&lock->spinlock);
 182                 spin_unlock(&res->spinlock);
 183                 status = dlm_send_remote_unlock_request(dlm, res, lock, lksb,
 184                                                         flags, owner);
 185                 spin_lock(&res->spinlock);
 186                 spin_lock(&lock->spinlock);
 187                 /* if the master told us the lock was already granted,
 188                  * let the ast handle all of these actions */
 189                 if (status == DLM_CANCELGRANT) {
 190                         actions &= ~(DLM_UNLOCK_REMOVE_LOCK|
 191                                      DLM_UNLOCK_REGRANT_LOCK|
 192                                      DLM_UNLOCK_CLEAR_CONVERT_TYPE);
 193                 } else if (status == DLM_RECOVERING ||
 194                            status == DLM_MIGRATING ||
 195                            status == DLM_FORWARD ||
 196                            status == DLM_NOLOCKMGR
 197                            ) {
 198                         /* must clear the actions because this unlock
 199                          * is about to be retried.  cannot free or do
 200                          * any list manipulation. */
 201                         mlog(0, "%s:%.*s: clearing actions, %s\n",
 202                              dlm->name, res->lockname.len,
 203                              res->lockname.name,
 204                              status==DLM_RECOVERING?"recovering":
 205                              (status==DLM_MIGRATING?"migrating":
 206                                 (status == DLM_FORWARD ? "forward" :
 207                                                 "nolockmanager")));
 208                         actions = 0;
 209                 }
 210                 if (flags & LKM_CANCEL)
 211                         lock->cancel_pending = 0;
 212                 else {
 213                         if (!lock->unlock_pending)
 214                                 recovery_wait = 1;
 215                         else
 216                                 lock->unlock_pending = 0;
 217                 }
 218         }
 219
 220         /* get an extra ref on lock.  if we are just switching
 221          * lists here, we dont want the lock to go away. */
 222         dlm_lock_get(lock);
 223
 224         if (actions & DLM_UNLOCK_REMOVE_LOCK) {
 225                 list_del_init(&lock->list);
 226                 dlm_lock_put(lock);
 227         }
 228         if (actions & DLM_UNLOCK_REGRANT_LOCK) {
 229                 dlm_lock_get(lock);
 230                 list_add_tail(&lock->list, &res->granted);
 231         }
 232         if (actions & DLM_UNLOCK_CLEAR_CONVERT_TYPE) {
 233                 mlog(0, "clearing convert_type at %smaster node\n",
 234                      master_node ? "" : "non-");
 235                 lock->ml.convert_type = LKM_IVMODE;
 236         }
 237
 238         /* remove the extra ref on lock */
 239         dlm_lock_put(lock);
 240
 241 leave:
 242         res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
 243         if (!dlm_lock_on_list(&res->converting, lock))
 244                 BUG_ON(lock->ml.convert_type != LKM_IVMODE);
 245         else
 246                 BUG_ON(lock->ml.convert_type == LKM_IVMODE);
 247         spin_unlock(&lock->spinlock);
 248         spin_unlock(&res->spinlock);
 249         wake_up(&res->wq);
 250
 251         if (recovery_wait) {
 252                 spin_lock(&res->spinlock);
 253                 /* Unlock request will directly succeed after owner dies,
 254                  * and the lock is already removed from grant list. We have to
 255                  * wait for RECOVERING done or we miss the chance to purge it
 256                  * since the removement is much faster than RECOVERING proc.
 257                  */
 258                 __dlm_wait_on_lockres_flags(res, DLM_LOCK_RES_RECOVERING);
 259                 spin_unlock(&res->spinlock);
 260         }
 261
 262         /* let the caller's final dlm_lock_put handle the actual kfree */
 263         if (actions & DLM_UNLOCK_FREE_LOCK) {
 264                 /* this should always be coupled with list removal */
 265                 BUG_ON(!(actions & DLM_UNLOCK_REMOVE_LOCK));
 266                 mlog(0, "lock %u:%llu should be gone now! refs=%d\n",
 267                      dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
 268                      dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
 269                      atomic_read(&lock->lock_refs.refcount)-1);
 270                 dlm_lock_put(lock);
 271         }
 272         if (actions & DLM_UNLOCK_CALL_AST)
 273                 *call_ast = 1;
 274
 275         /* if cancel or unlock succeeded, lvb work is done */
 276         if (status == DLM_NORMAL)
 277                 lksb->flags &= ~(DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB);
 278
 279         return status;
 280 }
 281
 282 void dlm_commit_pending_unlock(struct dlm_lock_resource *res,
 283                                struct dlm_lock *lock)
 284 {
 285         /* leave DLM_LKSB_PUT_LVB on the lksb so any final
 286          * update of the lvb will be sent to the new master */
 287         list_del_init(&lock->list);
 288 }
 289
 290 void dlm_commit_pending_cancel(struct dlm_lock_resource *res,
 291                                struct dlm_lock *lock)
 292 {
 293         list_move_tail(&lock->list, &res->granted);
 294         lock->ml.convert_type = LKM_IVMODE;
 295 }
 296
 297
 298 static inline enum dlm_status dlmunlock_master(struct dlm_ctxt *dlm,
 299                                           struct dlm_lock_resource *res,
 300                                           struct dlm_lock *lock,
 301                                           struct dlm_lockstatus *lksb,
 302                                           int flags,
 303                                           int *call_ast)
 304 {
 305         return dlmunlock_common(dlm, res, lock, lksb, flags, call_ast, 1);
 306 }
 307
 308 static inline enum dlm_status dlmunlock_remote(struct dlm_ctxt *dlm,
 309                                           struct dlm_lock_resource *res,
 310                                           struct dlm_lock *lock,
 311                                           struct dlm_lockstatus *lksb,
 312                                           int flags, int *call_ast)
 313 {
 314         return dlmunlock_common(dlm, res, lock, lksb, flags, call_ast, 0);
 315 }
 316
 317 /*
 318  * locking:
 319  *   caller needs:  none
 320  *   taken:         none
 321  *   held on exit:  none
 322  * returns: DLM_NORMAL, DLM_NOLOCKMGR, status from network
 323  */
 324 static enum dlm_status dlm_send_remote_unlock_request(struct dlm_ctxt *dlm,
 325                                                  struct dlm_lock_resource *res,
 326                                                  struct dlm_lock *lock,
 327                                                  struct dlm_lockstatus *lksb,
 328                                                  int flags,
 329                                                  u8 owner)
 330 {
 331         struct dlm_unlock_lock unlock;
 332         int tmpret;
 333         enum dlm_status ret;
 334         int status = 0;
 335         struct kvec vec[2];
 336         size_t veclen = 1;
 337
 338         mlog(0, "%.*s\n", res->lockname.len, res->lockname.name);
 339
 340         if (owner == dlm->node_num) {
 341                 /* ended up trying to contact ourself.  this means
 342                  * that the lockres had been remote but became local
 343                  * via a migration.  just retry it, now as local */
 344                 mlog(0, "%s:%.*s: this node became the master due to a "
 345                      "migration, re-evaluate now\n", dlm->name,
 346                      res->lockname.len, res->lockname.name);
 347                 return DLM_FORWARD;
 348         }
 349
 350         memset(&unlock, 0, sizeof(unlock));
 351         unlock.node_idx = dlm->node_num;
 352         unlock.flags = cpu_to_be32(flags);
 353         unlock.cookie = lock->ml.cookie;
 354         unlock.namelen = res->lockname.len;
 355         memcpy(unlock.name, res->lockname.name, unlock.namelen);
 356
 357         vec[0].iov_len = sizeof(struct dlm_unlock_lock);
 358         vec[0].iov_base = &unlock;
 359
 360         if (flags & LKM_PUT_LVB) {
 361                 /* extra data to send if we are updating lvb */
 362                 vec[1].iov_len = DLM_LVB_LEN;
 363                 vec[1].iov_base = lock->lksb->lvb;
 364                 veclen++;
 365         }
 366
 367         tmpret = o2net_send_message_vec(DLM_UNLOCK_LOCK_MSG, dlm->key,
 368                                         vec, veclen, owner, &status);
 369         if (tmpret >= 0) {
 370                 // successfully sent and received
 371                 if (status == DLM_FORWARD)
 372                         mlog(0, "master was in-progress.  retry\n");
 373                 ret = status;
 374         } else {
 375                 mlog(ML_ERROR, "Error %d when sending message %u (key 0x%x) to "
 376                      "node %u\n", tmpret, DLM_UNLOCK_LOCK_MSG, dlm->key, owner);
 377                 if (dlm_is_host_down(tmpret)) {
 378                         /* NOTE: this seems strange, but it is what we want.
 379                          * when the master goes down during a cancel or
 380                          * unlock, the recovery code completes the operation
 381                          * as if the master had not died, then passes the
 382                          * updated state to the recovery master.  this thread
 383                          * just needs to finish out the operation and call
 384                          * the unlockast. */
 385                         if (dlm_is_node_dead(dlm, owner))
 386                                 ret = DLM_NORMAL;
 387                         else
 388                                 ret = DLM_NOLOCKMGR;
 389                 } else {
 390                         /* something bad.  this will BUG in ocfs2 */
 391                         ret = dlm_err_to_dlm_status(tmpret);
 392                 }
 393         }
 394
 395         return ret;
 396 }
 397
 398 /*
 399  * locking:
 400  *   caller needs:  none
 401  *   taken:         takes and drops res->spinlock
 402  *   held on exit:  none
 403  * returns: DLM_NORMAL, DLM_BADARGS, DLM_IVLOCKID,
 404  *          return value from dlmunlock_master
 405  */
 406 int dlm_unlock_lock_handler(struct o2net_msg *msg, u32 len, void *data,
 407                             void **ret_data)
 408 {
 409         struct dlm_ctxt *dlm = data;
 410         struct dlm_unlock_lock *unlock = (struct dlm_unlock_lock *)msg->buf;
 411         struct dlm_lock_resource *res = NULL;
 412         struct dlm_lock *lock = NULL;
 413         enum dlm_status status = DLM_NORMAL;
 414         int found = 0, i;
 415         struct dlm_lockstatus *lksb = NULL;
 416         int ignore;
 417         u32 flags;
 418         struct list_head *queue;
 419
 420         flags = be32_to_cpu(unlock->flags);
 421
 422         if (flags & LKM_GET_LVB) {
 423                 mlog(ML_ERROR, "bad args!  GET_LVB specified on unlock!\n");
 424                 return DLM_BADARGS;
 425         }
 426
 427         if ((flags & (LKM_PUT_LVB|LKM_CANCEL)) == (LKM_PUT_LVB|LKM_CANCEL)) {
 428                 mlog(ML_ERROR, "bad args!  cannot modify lvb on a CANCEL "
 429                      "request!\n");
 430                 return DLM_BADARGS;
 431         }
 432
 433         if (unlock->namelen > DLM_LOCKID_NAME_MAX) {
 434                 mlog(ML_ERROR, "Invalid name length in unlock handler!\n");
 435                 return DLM_IVBUFLEN;
 436         }
 437
 438         if (!dlm_grab(dlm))
 439                 return DLM_FORWARD;
 440
 441         mlog_bug_on_msg(!dlm_domain_fully_joined(dlm),
 442                         "Domain %s not fully joined!\n", dlm->name);
 443
 444         mlog(0, "lvb: %s\n", flags & LKM_PUT_LVB ? "put lvb" : "none");
 445
 446         res = dlm_lookup_lockres(dlm, unlock->name, unlock->namelen);
 447         if (!res) {
 448                 /* We assume here that a no lock resource simply means
 449                  * it was migrated away and destroyed before the other
 450                  * node could detect it. */
 451                 mlog(0, "returning DLM_FORWARD -- res no longer exists\n");
 452                 status = DLM_FORWARD;
 453                 goto not_found;
 454         }
 455
 456         queue=&res->granted;
 457         found = 0;
 458         spin_lock(&res->spinlock);
 459         if (res->state & DLM_LOCK_RES_RECOVERING) {
 460                 spin_unlock(&res->spinlock);
 461                 mlog(0, "returning DLM_RECOVERING\n");
 462                 status = DLM_RECOVERING;
 463                 goto leave;
 464         }
 465
 466         if (res->state & DLM_LOCK_RES_MIGRATING) {
 467                 spin_unlock(&res->spinlock);
 468                 mlog(0, "returning DLM_MIGRATING\n");
 469                 status = DLM_MIGRATING;
 470                 goto leave;
 471         }
 472
 473         if (res->owner != dlm->node_num) {
 474                 spin_unlock(&res->spinlock);
 475                 mlog(0, "returning DLM_FORWARD -- not master\n");
 476                 status = DLM_FORWARD;
 477                 goto leave;
 478         }
 479
 480         for (i=0; i<3; i++) {
 481                 list_for_each_entry(lock, queue, list) {
 482                         if (lock->ml.cookie == unlock->cookie &&
 483                             lock->ml.node == unlock->node_idx) {
 484                                 dlm_lock_get(lock);
 485                                 found = 1;
 486                                 break;
 487                         }
 488                 }
 489                 if (found)
 490                         break;
 491                 /* scan granted -> converting -> blocked queues */
 492                 queue++;
 493         }
 494         spin_unlock(&res->spinlock);
 495         if (!found) {
 496                 status = DLM_IVLOCKID;
 497                 goto not_found;
 498         }
 499
 500         /* lock was found on queue */
 501         lksb = lock->lksb;
 502         if (flags & (LKM_VALBLK|LKM_PUT_LVB) &&
 503             lock->ml.type != LKM_EXMODE)
 504                 flags &= ~(LKM_VALBLK|LKM_PUT_LVB);
 505
 506         /* unlockast only called on originating node */
 507         if (flags & LKM_PUT_LVB) {
 508                 lksb->flags |= DLM_LKSB_PUT_LVB;
 509                 memcpy(&lksb->lvb[0], &unlock->lvb[0], DLM_LVB_LEN);
 510         }
 511
 512         /* if this is in-progress, propagate the DLM_FORWARD
 513          * all the way back out */
 514         status = dlmunlock_master(dlm, res, lock, lksb, flags, &ignore);
 515         if (status == DLM_FORWARD)
 516                 mlog(0, "lockres is in progress\n");
 517
 518         if (flags & LKM_PUT_LVB)
 519                 lksb->flags &= ~DLM_LKSB_PUT_LVB;
 520
 521         dlm_lockres_calc_usage(dlm, res);
 522         dlm_kick_thread(dlm, res);
 523
 524 not_found:
 525         if (!found)
 526                 mlog(ML_ERROR, "failed to find lock to unlock! "
 527                                "cookie=%u:%llu\n",
 528                      dlm_get_lock_cookie_node(be64_to_cpu(unlock->cookie)),
 529                      dlm_get_lock_cookie_seq(be64_to_cpu(unlock->cookie)));
 530         else
 531                 dlm_lock_put(lock);
 532
 533 leave:
 534         if (res)
 535                 dlm_lockres_put(res);
 536
 537         dlm_put(dlm);
 538
 539         return status;
 540 }
 541
 542
 543 static enum dlm_status dlm_get_cancel_actions(struct dlm_ctxt *dlm,
 544                                               struct dlm_lock_resource *res,
 545                                               struct dlm_lock *lock,
 546                                               struct dlm_lockstatus *lksb,
 547                                               int *actions)
 548 {
 549         enum dlm_status status;
 550
 551         if (dlm_lock_on_list(&res->blocked, lock)) {
 552                 /* cancel this outright */
 553                 status = DLM_NORMAL;
 554                 *actions = (DLM_UNLOCK_CALL_AST |
 555                             DLM_UNLOCK_REMOVE_LOCK);
 556         } else if (dlm_lock_on_list(&res->converting, lock)) {
 557                 /* cancel the request, put back on granted */
 558                 status = DLM_NORMAL;
 559                 *actions = (DLM_UNLOCK_CALL_AST |
 560                             DLM_UNLOCK_REMOVE_LOCK |
 561                             DLM_UNLOCK_REGRANT_LOCK |
 562                             DLM_UNLOCK_CLEAR_CONVERT_TYPE);
 563         } else if (dlm_lock_on_list(&res->granted, lock)) {
 564                 /* too late, already granted. */
 565                 status = DLM_CANCELGRANT;
 566                 *actions = DLM_UNLOCK_CALL_AST;
 567         } else {
 568                 mlog(ML_ERROR, "lock to cancel is not on any list!\n");
 569                 status = DLM_IVLOCKID;
 570                 *actions = 0;
 571         }
 572         return status;
 573 }
 574
 575 static enum dlm_status dlm_get_unlock_actions(struct dlm_ctxt *dlm,
 576                                               struct dlm_lock_resource *res,
 577                                               struct dlm_lock *lock,
 578                                               struct dlm_lockstatus *lksb,
 579                                               int *actions)
 580 {
 581         enum dlm_status status;
 582
 583         /* unlock request */
 584         if (!dlm_lock_on_list(&res->granted, lock)) {
 585                 status = DLM_DENIED;
 586                 dlm_error(status);
 587                 *actions = 0;
 588         } else {
 589                 /* unlock granted lock */
 590                 status = DLM_NORMAL;
 591                 *actions = (DLM_UNLOCK_FREE_LOCK |
 592                             DLM_UNLOCK_CALL_AST |
 593                             DLM_UNLOCK_REMOVE_LOCK);
 594         }
 595         return status;
 596 }
 597
 598 /* there seems to be no point in doing this async
 599  * since (even for the remote case) there is really
 600  * no work to queue up... so just do it and fire the
 601  * unlockast by hand when done... */
 602 enum dlm_status dlmunlock(struct dlm_ctxt *dlm, struct dlm_lockstatus *lksb,
 603                           int flags, dlm_astunlockfunc_t *unlockast, void *data)
 604 {
 605         enum dlm_status status;
 606         struct dlm_lock_resource *res;
 607         struct dlm_lock *lock = NULL;
 608         int call_ast, is_master;
 609
 610         if (!lksb) {
 611                 dlm_error(DLM_BADARGS);
 612                 return DLM_BADARGS;
 613         }
 614
 615         if (flags & ~(LKM_CANCEL | LKM_VALBLK | LKM_INVVALBLK)) {
 616                 dlm_error(DLM_BADPARAM);
 617                 return DLM_BADPARAM;
 618         }
 619
 620         if ((flags & (LKM_VALBLK | LKM_CANCEL)) == (LKM_VALBLK | LKM_CANCEL)) {
 621                 mlog(0, "VALBLK given with CANCEL: ignoring VALBLK\n");
 622                 flags &= ~LKM_VALBLK;
 623         }
 624
 625         if (!lksb->lockid || !lksb->lockid->lockres) {
 626                 dlm_error(DLM_BADPARAM);
 627                 return DLM_BADPARAM;
 628         }
 629
 630         lock = lksb->lockid;
 631         BUG_ON(!lock);
 632         dlm_lock_get(lock);
 633
 634         res = lock->lockres;
 635         BUG_ON(!res);
 636         dlm_lockres_get(res);
 637 retry:
 638         call_ast = 0;
 639         /* need to retry up here because owner may have changed */
 640         mlog(0, "lock=%p res=%p\n", lock, res);
 641
 642         spin_lock(&res->spinlock);
 643         is_master = (res->owner == dlm->node_num);
 644         if (flags & LKM_VALBLK && lock->ml.type != LKM_EXMODE)
 645                 flags &= ~LKM_VALBLK;
 646         spin_unlock(&res->spinlock);
 647
 648         if (is_master) {
 649                 status = dlmunlock_master(dlm, res, lock, lksb, flags,
 650                                           &call_ast);
 651                 mlog(0, "done calling dlmunlock_master: returned %d, "
 652                      "call_ast is %d\n", status, call_ast);
 653         } else {
 654                 status = dlmunlock_remote(dlm, res, lock, lksb, flags,
 655                                           &call_ast);
 656                 mlog(0, "done calling dlmunlock_remote: returned %d, "
 657                      "call_ast is %d\n", status, call_ast);
 658         }
 659
 660         if (status == DLM_RECOVERING ||
 661             status == DLM_MIGRATING ||
 662             status == DLM_FORWARD ||
 663             status == DLM_NOLOCKMGR) {
 664
 665                 /* We want to go away for a tiny bit to allow recovery
 666                  * / migration to complete on this resource. I don't
 667                  * know of any wait queue we could sleep on as this
 668                  * may be happening on another node. Perhaps the
 669                  * proper solution is to queue up requests on the
 670                  * other end? */
 671
 672                 /* do we want to yield(); ?? */
 673                 msleep(50);
 674
 675                 mlog(0, "retrying unlock due to pending recovery/"
 676                      "migration/in-progress/reconnect\n");
 677                 goto retry;
 678         }
 679
 680         if (call_ast) {
 681                 mlog(0, "calling unlockast(%p, %d)\n", data, status);
 682                 if (is_master) {
 683                         /* it is possible that there is one last bast
 684                          * pending.  make sure it is flushed, then
 685                          * call the unlockast.
 686                          * not an issue if this is a mastered remotely,
 687                          * since this lock has been removed from the
 688                          * lockres queues and cannot be found. */
 689                         dlm_kick_thread(dlm, NULL);
 690                         wait_event(dlm->ast_wq,
 691                                    dlm_lock_basts_flushed(dlm, lock));
 692                 }
 693                 (*unlockast)(data, status);
 694         }
 695
 696         if (status == DLM_CANCELGRANT)
 697                 status = DLM_NORMAL;
 698
 699         if (status == DLM_NORMAL) {
 700                 mlog(0, "kicking the thread\n");
 701                 dlm_kick_thread(dlm, res);
 702         } else
 703                 dlm_error(status);
 704
 705         dlm_lockres_calc_usage(dlm, res);
 706         dlm_lockres_put(res);
 707         dlm_lock_put(lock);
 708
 709         mlog(0, "returning status=%d!\n", status);
 710         return status;
 711 }
 712 EXPORT_SYMBOL_GPL(dlmunlock);
 713