linux/fs/ocfs2/dlm/dlmunlock.c
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   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
  58static 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);
  63static 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
  69static 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 */
  98static 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
 237leave:
 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
 267void 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
 275void 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
 283static 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
 293static 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 */
 309static 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 */
 391int 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
 509not_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
 518leave:
 519        if (res)
 520                dlm_lockres_put(res);
 521
 522        dlm_put(dlm);
 523
 524        return status;
 525}
 526
 527
 528static 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
 560static 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... */
 587enum 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);
 622retry:
 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}
 697EXPORT_SYMBOL_GPL(dlmunlock);
 698
 699