lustre/lov/lov_lock.c

   1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
   2  * vim:expandtab:shiftwidth=8:tabstop=8:
   3  *
   4  * GPL HEADER START
   5  *
   6  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 only,
  10  * as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License version 2 for more details (a copy is included
  16  * in the LICENSE file that accompanied this code).
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * version 2 along with this program; If not, see
  20  * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
  21  *
  22  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  23  * CA 95054 USA or visit www.sun.com if you need additional information or
  24  * have any questions.
  25  *
  26  * GPL HEADER END
  27  */
  28 /*
  29  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
  30  * Use is subject to license terms.
  31  */
  32 /*
  33  * This file is part of Lustre, http://www.lustre.org/
  34  * Lustre is a trademark of Sun Microsystems, Inc.
  35  *
  36  * Implementation of cl_lock for LOV layer.
  37  *
  38  *   Author: Nikita Danilov <nikita.danilov@sun.com>
  39  */
  40
  41 #define DEBUG_SUBSYSTEM S_LOV
  42
  43 #include "lov_cl_internal.h"
  44
  45 /** \addtogroup lov
  46  *  @{
  47  */
  48
  49 static struct cl_lock_closure *lov_closure_get(const struct lu_env *env,
  50                                                struct cl_lock *parent);
  51
  52 static int lov_lock_unuse(const struct lu_env *env,
  53                           const struct cl_lock_slice *slice);
  54 /*****************************************************************************
  55  *
  56  * Lov lock operations.
  57  *
  58  */
  59
  60 static struct lov_sublock_env *lov_sublock_env_get(const struct lu_env *env,
  61                                                    struct cl_lock *parent,
  62                                                    struct lov_lock_sub *lls)
  63 {
  64         struct lov_sublock_env *subenv;
  65         struct lov_io          *lio    = lov_env_io(env);
  66         struct cl_io           *io     = lio->lis_cl.cis_io;
  67         struct lov_io_sub      *sub;
  68
  69         subenv = &lov_env_session(env)->ls_subenv;
  70
  71         /*
  72          * FIXME: We tend to use the subio's env & io to call the sublock
  73          * lock operations because osc lock sometimes stores some control
  74          * variables in thread's IO infomation(Now only lockless information).
  75          * However, if the lock's host(object) is different from the object
  76          * for current IO, we have no way to get the subenv and subio because
  77          * they are not initialized at all. As a temp fix, in this case,
  78          * we still borrow the parent's env to call sublock operations.
  79          */
  80         if (!io || !cl_object_same(io->ci_obj, parent->cll_descr.cld_obj)) {
  81                 subenv->lse_env = env;
  82                 subenv->lse_io  = io;
  83                 subenv->lse_sub = NULL;
  84         } else {
  85                 sub = lov_sub_get(env, lio, lls->sub_stripe);
  86                 if (!IS_ERR(sub)) {
  87                         subenv->lse_env = sub->sub_env;
  88                         subenv->lse_io  = sub->sub_io;
  89                         subenv->lse_sub = sub;
  90                 } else {
  91                         subenv = (void*)sub;
  92                 }
  93         }
  94         return subenv;
  95 }
  96
  97 static void lov_sublock_env_put(struct lov_sublock_env *subenv)
  98 {
  99         if (subenv && subenv->lse_sub)
 100                 lov_sub_put(subenv->lse_sub);
 101 }
 102
 103 static void lov_sublock_adopt(const struct lu_env *env, struct lov_lock *lck,
 104                               struct cl_lock *sublock, int idx,
 105                               struct lov_lock_link *link)
 106 {
 107         struct lovsub_lock *lsl;
 108         struct cl_lock     *parent = lck->lls_cl.cls_lock;
 109         int                 rc;
 110
 111         LASSERT(cl_lock_is_mutexed(parent));
 112         LASSERT(cl_lock_is_mutexed(sublock));
 113         ENTRY;
 114
 115         lsl = cl2sub_lock(sublock);
 116         /*
 117          * check that sub-lock doesn't have lock link to this top-lock.
 118          */
 119         LASSERT(lov_lock_link_find(env, lck, lsl) == NULL);
 120         LASSERT(idx < lck->lls_nr);
 121
 122         lck->lls_sub[idx].sub_lock = lsl;
 123         lck->lls_nr_filled++;
 124         LASSERT(lck->lls_nr_filled <= lck->lls_nr);
 125         list_add_tail(&link->lll_list, &lsl->lss_parents);
 126         link->lll_idx = idx;
 127         link->lll_super = lck;
 128         cl_lock_get(parent);
 129         lu_ref_add(&parent->cll_reference, "lov-child", sublock);
 130         lck->lls_sub[idx].sub_flags |= LSF_HELD;
 131         cl_lock_user_add(env, sublock);
 132
 133         rc = lov_sublock_modify(env, lck, lsl, &sublock->cll_descr, idx);
 134         LASSERT(rc == 0); /* there is no way this can fail, currently */
 135         EXIT;
 136 }
 137
 138 static struct cl_lock *lov_sublock_alloc(const struct lu_env *env,
 139                                          const struct cl_io *io,
 140                                          struct lov_lock *lck,
 141                                          int idx, struct lov_lock_link **out)
 142 {
 143         struct cl_lock       *sublock;
 144         struct cl_lock       *parent;
 145         struct lov_lock_link *link;
 146
 147         LASSERT(idx < lck->lls_nr);
 148         ENTRY;
 149
 150         OBD_SLAB_ALLOC_PTR_GFP(link, lov_lock_link_kmem, CFS_ALLOC_IO);
 151         if (link != NULL) {
 152                 struct lov_sublock_env *subenv;
 153                 struct lov_lock_sub  *lls;
 154                 struct cl_lock_descr *descr;
 155
 156                 parent = lck->lls_cl.cls_lock;
 157                 lls    = &lck->lls_sub[idx];
 158                 descr  = &lls->sub_descr;
 159
 160                 subenv = lov_sublock_env_get(env, parent, lls);
 161                 if (!IS_ERR(subenv)) {
 162                         /* CAVEAT: Don't try to add a field in lov_lock_sub
 163                          * to remember the subio. This is because lock is able
 164                          * to be cached, but this is not true for IO. This
 165                          * further means a sublock might be referenced in
 166                          * different io context. -jay */
 167
 168                         sublock = cl_lock_hold(subenv->lse_env, subenv->lse_io,
 169                                                descr, "lov-parent", parent);
 170                         lov_sublock_env_put(subenv);
 171                 } else {
 172                         /* error occurs. */
 173                         sublock = (void*)subenv;
 174                 }
 175
 176                 if (!IS_ERR(sublock))
 177                         *out = link;
 178                 else
 179                         OBD_SLAB_FREE_PTR(link, lov_lock_link_kmem);
 180         } else
 181                 sublock = ERR_PTR(-ENOMEM);
 182         RETURN(sublock);
 183 }
 184
 185 static void lov_sublock_unlock(const struct lu_env *env,
 186                                struct lovsub_lock *lsl,
 187                                struct cl_lock_closure *closure,
 188                                struct lov_sublock_env *subenv)
 189 {
 190         ENTRY;
 191         lov_sublock_env_put(subenv);
 192         lsl->lss_active = NULL;
 193         cl_lock_disclosure(env, closure);
 194         EXIT;
 195 }
 196
 197 static int lov_sublock_lock(const struct lu_env *env,
 198                             struct lov_lock *lck,
 199                             struct lov_lock_sub *lls,
 200                             struct cl_lock_closure *closure,
 201                             struct lov_sublock_env **lsep)
 202 {
 203         struct lovsub_lock *sublock;
 204         struct cl_lock     *child;
 205         int                 result = 0;
 206         ENTRY;
 207
 208         LASSERT(list_empty(&closure->clc_list));
 209
 210         sublock = lls->sub_lock;
 211         child = sublock->lss_cl.cls_lock;
 212         result = cl_lock_closure_build(env, child, closure);
 213         if (result == 0) {
 214                 struct cl_lock *parent = closure->clc_origin;
 215
 216                 LASSERT(cl_lock_is_mutexed(child));
 217                 sublock->lss_active = parent;
 218
 219                 if (unlikely((child->cll_state == CLS_FREEING) ||
 220                              (child->cll_flags & CLF_CANCELLED))) {
 221                         struct lov_lock_link *link;
 222                         /*
 223                          * we could race with lock deletion which temporarily
 224                          * put the lock in freeing state, bug 19080.
 225                          */
 226                         LASSERT(!(lls->sub_flags & LSF_HELD));
 227
 228                         link = lov_lock_link_find(env, lck, sublock);
 229                         LASSERT(link != NULL);
 230                         lov_lock_unlink(env, link, sublock);
 231                         lov_sublock_unlock(env, sublock, closure, NULL);
 232                         lck->lls_cancel_race = 1;
 233                         result = CLO_REPEAT;
 234                 } else if (lsep) {
 235                         struct lov_sublock_env *subenv;
 236                         subenv = lov_sublock_env_get(env, parent, lls);
 237                         if (IS_ERR(subenv)) {
 238                                 lov_sublock_unlock(env, sublock,
 239                                                    closure, NULL);
 240                                 result = PTR_ERR(subenv);
 241                         } else {
 242                                 *lsep = subenv;
 243                         }
 244                 }
 245         }
 246         RETURN(result);
 247 }
 248
 249 /**
 250  * Updates the result of a top-lock operation from a result of sub-lock
 251  * sub-operations. Top-operations like lov_lock_{enqueue,use,unuse}() iterate
 252  * over sub-locks and lov_subresult() is used to calculate return value of a
 253  * top-operation. To this end, possible return values of sub-operations are
 254  * ordered as
 255  *
 256  *     - 0                  success
 257  *     - CLO_WAIT           wait for event
 258  *     - CLO_REPEAT         repeat top-operation
 259  *     - -ne                fundamental error
 260  *
 261  * Top-level return code can only go down through this list. CLO_REPEAT
 262  * overwrites CLO_WAIT, because lock mutex was released and sleeping condition
 263  * has to be rechecked by the upper layer.
 264  */
 265 static int lov_subresult(int result, int rc)
 266 {
 267         int result_rank;
 268         int rc_rank;
 269
 270         LASSERT(result <= 0 || result == CLO_REPEAT || result == CLO_WAIT);
 271         LASSERT(rc <= 0 || rc == CLO_REPEAT || rc == CLO_WAIT);
 272         CLASSERT(CLO_WAIT < CLO_REPEAT);
 273
 274         ENTRY;
 275
 276         /* calculate ranks in the ordering above */
 277         result_rank = result < 0 ? 1 + CLO_REPEAT : result;
 278         rc_rank = rc < 0 ? 1 + CLO_REPEAT : rc;
 279
 280         if (result_rank < rc_rank)
 281                 result = rc;
 282         RETURN(result);
 283 }
 284
 285 /**
 286  * Creates sub-locks for a given lov_lock for the first time.
 287  *
 288  * Goes through all sub-objects of top-object, and creates sub-locks on every
 289  * sub-object intersecting with top-lock extent. This is complicated by the
 290  * fact that top-lock (that is being created) can be accessed concurrently
 291  * through already created sub-locks (possibly shared with other top-locks).
 292  */
 293 static int lov_lock_sub_init(const struct lu_env *env,
 294                              struct lov_lock *lck, const struct cl_io *io)
 295 {
 296         int result = 0;
 297         int i;
 298         int nr;
 299         obd_off start;
 300         obd_off end;
 301         obd_off file_start;
 302         obd_off file_end;
 303
 304         struct lov_object       *loo    = cl2lov(lck->lls_cl.cls_obj);
 305         struct lov_layout_raid0 *r0     = lov_r0(loo);
 306         struct cl_lock          *parent = lck->lls_cl.cls_lock;
 307
 308         ENTRY;
 309
 310         lck->lls_orig = parent->cll_descr;
 311         file_start = cl_offset(lov2cl(loo), parent->cll_descr.cld_start);
 312         file_end   = cl_offset(lov2cl(loo), parent->cll_descr.cld_end + 1) - 1;
 313
 314         for (i = 0, nr = 0; i < r0->lo_nr; i++) {
 315                 /*
 316                  * XXX for wide striping smarter algorithm is desirable,
 317                  * breaking out of the loop, early.
 318                  */
 319                 if (lov_stripe_intersects(r0->lo_lsm, i,
 320                                           file_start, file_end, &start, &end))
 321                         nr++;
 322         }
 323         LASSERT(nr > 0);
 324         OBD_ALLOC(lck->lls_sub, nr * sizeof lck->lls_sub[0]);
 325         if (lck->lls_sub == NULL)
 326                 RETURN(-ENOMEM);
 327
 328         lck->lls_nr = nr;
 329         /*
 330          * First, fill in sub-lock descriptions in
 331          * lck->lls_sub[].sub_descr. They are used by lov_sublock_alloc()
 332          * (called below in this function, and by lov_lock_enqueue()) to
 333          * create sub-locks. At this moment, no other thread can access
 334          * top-lock.
 335          */
 336         for (i = 0, nr = 0; i < r0->lo_nr; ++i) {
 337                 if (lov_stripe_intersects(r0->lo_lsm, i,
 338                                           file_start, file_end, &start, &end)) {
 339                         struct cl_lock_descr *descr;
 340
 341                         descr = &lck->lls_sub[nr].sub_descr;
 342
 343                         LASSERT(descr->cld_obj == NULL);
 344                         descr->cld_obj   = lovsub2cl(r0->lo_sub[i]);
 345                         descr->cld_start = cl_index(descr->cld_obj, start);
 346                         descr->cld_end   = cl_index(descr->cld_obj, end);
 347                         descr->cld_mode  = parent->cll_descr.cld_mode;
 348                         descr->cld_gid   = parent->cll_descr.cld_gid;
 349                         descr->cld_enq_flags   = parent->cll_descr.cld_enq_flags;
 350                         /* XXX has no effect */
 351                         lck->lls_sub[nr].sub_got = *descr;
 352                         lck->lls_sub[nr].sub_stripe = i;
 353                         nr++;
 354                 }
 355         }
 356         LASSERT(nr == lck->lls_nr);
 357         /*
 358          * Then, create sub-locks. Once at least one sub-lock was created,
 359          * top-lock can be reached by other threads.
 360          */
 361         for (i = 0; i < lck->lls_nr; ++i) {
 362                 struct cl_lock       *sublock;
 363                 struct lov_lock_link *link;
 364
 365                 if (lck->lls_sub[i].sub_lock == NULL) {
 366                         sublock = lov_sublock_alloc(env, io, lck, i, &link);
 367                         if (IS_ERR(sublock)) {
 368                                 result = PTR_ERR(sublock);
 369                                 break;
 370                         }
 371                         cl_lock_get_trust(sublock);
 372                         cl_lock_mutex_get(env, sublock);
 373                         cl_lock_mutex_get(env, parent);
 374                         /*
 375                          * recheck under mutex that sub-lock wasn't created
 376                          * concurrently, and that top-lock is still alive.
 377                          */
 378                         if (lck->lls_sub[i].sub_lock == NULL &&
 379                             parent->cll_state < CLS_FREEING) {
 380                                 lov_sublock_adopt(env, lck, sublock, i, link);
 381                                 cl_lock_mutex_put(env, parent);
 382                         } else {
 383                                 OBD_SLAB_FREE_PTR(link, lov_lock_link_kmem);
 384                                 cl_lock_mutex_put(env, parent);
 385                                 cl_lock_unhold(env, sublock,
 386                                                "lov-parent", parent);
 387                         }
 388                         cl_lock_mutex_put(env, sublock);
 389                         cl_lock_put(env, sublock);
 390                 }
 391         }
 392         /*
 393          * Some sub-locks can be missing at this point. This is not a problem,
 394          * because enqueue will create them anyway. Main duty of this function
 395          * is to fill in sub-lock descriptions in a race free manner.
 396          */
 397         RETURN(result);
 398 }
 399
 400 static int lov_sublock_release(const struct lu_env *env, struct lov_lock *lck,
 401                                int i, int deluser, int rc)
 402 {
 403         struct cl_lock *parent = lck->lls_cl.cls_lock;
 404
 405         LASSERT(cl_lock_is_mutexed(parent));
 406         ENTRY;
 407
 408         if (lck->lls_sub[i].sub_flags & LSF_HELD) {
 409                 struct cl_lock    *sublock;
 410                 int dying;
 411
 412                 LASSERT(lck->lls_sub[i].sub_lock != NULL);
 413                 sublock = lck->lls_sub[i].sub_lock->lss_cl.cls_lock;
 414                 LASSERT(cl_lock_is_mutexed(sublock));
 415
 416                 lck->lls_sub[i].sub_flags &= ~LSF_HELD;
 417                 if (deluser)
 418                         cl_lock_user_del(env, sublock);
 419                 /*
 420                  * If the last hold is released, and cancellation is pending
 421                  * for a sub-lock, release parent mutex, to avoid keeping it
 422                  * while sub-lock is being paged out.
 423                  */
 424                 dying = (sublock->cll_descr.cld_mode == CLM_PHANTOM ||
 425                          sublock->cll_descr.cld_mode == CLM_GROUP ||
 426                          (sublock->cll_flags & (CLF_CANCELPEND|CLF_DOOMED))) &&
 427                         sublock->cll_holds == 1;
 428                 if (dying)
 429                         cl_lock_mutex_put(env, parent);
 430                 cl_lock_unhold(env, sublock, "lov-parent", parent);
 431                 if (dying) {
 432                         cl_lock_mutex_get(env, parent);
 433                         rc = lov_subresult(rc, CLO_REPEAT);
 434                 }
 435                 /*
 436                  * From now on lck->lls_sub[i].sub_lock is a "weak" pointer,
 437                  * not backed by a reference on a
 438                  * sub-lock. lovsub_lock_delete() will clear
 439                  * lck->lls_sub[i].sub_lock under semaphores, just before
 440                  * sub-lock is destroyed.
 441                  */
 442         }
 443         RETURN(rc);
 444 }
 445
 446 static void lov_sublock_hold(const struct lu_env *env, struct lov_lock *lck,
 447                              int i)
 448 {
 449         struct cl_lock *parent = lck->lls_cl.cls_lock;
 450
 451         LASSERT(cl_lock_is_mutexed(parent));
 452         ENTRY;
 453
 454         if (!(lck->lls_sub[i].sub_flags & LSF_HELD)) {
 455                 struct cl_lock *sublock;
 456
 457                 LASSERT(lck->lls_sub[i].sub_lock != NULL);
 458                 sublock = lck->lls_sub[i].sub_lock->lss_cl.cls_lock;
 459                 LASSERT(cl_lock_is_mutexed(sublock));
 460                 LASSERT(sublock->cll_state != CLS_FREEING);
 461
 462                 lck->lls_sub[i].sub_flags |= LSF_HELD;
 463
 464                 cl_lock_get_trust(sublock);
 465                 cl_lock_hold_add(env, sublock, "lov-parent", parent);
 466                 cl_lock_user_add(env, sublock);
 467                 cl_lock_put(env, sublock);
 468         }
 469         EXIT;
 470 }
 471
 472 static void lov_lock_fini(const struct lu_env *env,
 473                           struct cl_lock_slice *slice)
 474 {
 475         struct lov_lock *lck;
 476         int i;
 477
 478         ENTRY;
 479         lck = cl2lov_lock(slice);
 480         LASSERT(lck->lls_nr_filled == 0);
 481         if (lck->lls_sub != NULL) {
 482                 for (i = 0; i < lck->lls_nr; ++i)
 483                         /*
 484                          * No sub-locks exists at this point, as sub-lock has
 485                          * a reference on its parent.
 486                          */
 487                         LASSERT(lck->lls_sub[i].sub_lock == NULL);
 488                 OBD_FREE(lck->lls_sub, lck->lls_nr * sizeof lck->lls_sub[0]);
 489         }
 490         OBD_SLAB_FREE_PTR(lck, lov_lock_kmem);
 491         EXIT;
 492 }
 493
 494 /**
 495  *
 496  * \retval 0 if state-transition can proceed
 497  * \retval -ve otherwise.
 498  */
 499 static int lov_lock_enqueue_wait(const struct lu_env *env,
 500                                  struct lov_lock *lck,
 501                                  struct cl_lock *sublock)
 502 {
 503         struct cl_lock *lock     = lck->lls_cl.cls_lock;
 504         struct cl_lock *conflict = sublock->cll_conflict;
 505         int result = CLO_REPEAT;
 506         ENTRY;
 507
 508         LASSERT(cl_lock_is_mutexed(lock));
 509         LASSERT(cl_lock_is_mutexed(sublock));
 510         LASSERT(sublock->cll_state == CLS_QUEUING);
 511         LASSERT(conflict != NULL);
 512
 513         sublock->cll_conflict = NULL;
 514         cl_lock_mutex_put(env, lock);
 515         cl_lock_mutex_put(env, sublock);
 516
 517         LASSERT(cl_lock_nr_mutexed(env) == 0);
 518
 519         cl_lock_mutex_get(env, conflict);
 520         cl_lock_cancel(env, conflict);
 521         cl_lock_delete(env, conflict);
 522         while (conflict->cll_state != CLS_FREEING) {
 523                 int rc = 0;
 524
 525                 rc = cl_lock_state_wait(env, conflict);
 526                 if (rc == 0)
 527                         continue;
 528
 529                 result = lov_subresult(result, rc);
 530                 break;
 531         }
 532         cl_lock_mutex_put(env, conflict);
 533         lu_ref_del(&conflict->cll_reference, "cancel-wait", sublock);
 534         cl_lock_put(env, conflict);
 535
 536         cl_lock_mutex_get(env, lock);
 537         RETURN(result);
 538 }
 539
 540 /**
 541  * Tries to advance a state machine of a given sub-lock toward enqueuing of
 542  * the top-lock.
 543  *
 544  * \retval 0 if state-transition can proceed
 545  * \retval -ve otherwise.
 546  */
 547 static int lov_lock_enqueue_one(const struct lu_env *env, struct lov_lock *lck,
 548                                 struct cl_lock *sublock,
 549                                 struct cl_io *io, __u32 enqflags, int last)
 550 {
 551         int result;
 552         ENTRY;
 553
 554         /* first, try to enqueue a sub-lock ... */
 555         result = cl_enqueue_try(env, sublock, io, enqflags);
 556         if (sublock->cll_state == CLS_ENQUEUED)
 557                 /* if it is enqueued, try to `wait' on it---maybe it's already
 558                  * granted */
 559                 result = cl_wait_try(env, sublock);
 560         /*
 561          * If CEF_ASYNC flag is set, then all sub-locks can be enqueued in
 562          * parallel, otherwise---enqueue has to wait until sub-lock is granted
 563          * before proceeding to the next one.
 564          */
 565         if (result == CLO_WAIT && sublock->cll_state <= CLS_HELD &&
 566             enqflags & CEF_ASYNC && !last)
 567                 result = 0;
 568         RETURN(result);
 569 }
 570
 571 /**
 572  * Helper function for lov_lock_enqueue() that creates missing sub-lock.
 573  */
 574 static int lov_sublock_fill(const struct lu_env *env, struct cl_lock *parent,
 575                             struct cl_io *io, struct lov_lock *lck, int idx)
 576 {
 577         struct lov_lock_link *link;
 578         struct cl_lock       *sublock;
 579         int                   result;
 580
 581         LASSERT(parent->cll_depth == 1);
 582         cl_lock_mutex_put(env, parent);
 583         sublock = lov_sublock_alloc(env, io, lck, idx, &link);
 584         if (!IS_ERR(sublock))
 585                 cl_lock_mutex_get(env, sublock);
 586         cl_lock_mutex_get(env, parent);
 587
 588         if (!IS_ERR(sublock)) {
 589                 cl_lock_get_trust(sublock);
 590                 if (parent->cll_state == CLS_QUEUING &&
 591                     lck->lls_sub[idx].sub_lock == NULL) {
 592                         lov_sublock_adopt(env, lck, sublock, idx, link);
 593                 } else {
 594                         OBD_SLAB_FREE_PTR(link, lov_lock_link_kmem);
 595                         /* other thread allocated sub-lock, or enqueue is no
 596                          * longer going on */
 597                         cl_lock_mutex_put(env, parent);
 598                         cl_lock_unhold(env, sublock, "lov-parent", parent);
 599                         cl_lock_mutex_get(env, parent);
 600                 }
 601                 cl_lock_mutex_put(env, sublock);
 602                 cl_lock_put(env, sublock);
 603                 result = CLO_REPEAT;
 604         } else
 605                 result = PTR_ERR(sublock);
 606         return result;
 607 }
 608
 609 /**
 610  * Implementation of cl_lock_operations::clo_enqueue() for lov layer. This
 611  * function is rather subtle, as it enqueues top-lock (i.e., advances top-lock
 612  * state machine from CLS_QUEUING to CLS_ENQUEUED states) by juggling sub-lock
 613  * state machines in the face of sub-locks sharing (by multiple top-locks),
 614  * and concurrent sub-lock cancellations.
 615  */
 616 static int lov_lock_enqueue(const struct lu_env *env,
 617                             const struct cl_lock_slice *slice,
 618                             struct cl_io *io, __u32 enqflags)
 619 {
 620         struct cl_lock         *lock    = slice->cls_lock;
 621         struct lov_lock        *lck     = cl2lov_lock(slice);
 622         struct cl_lock_closure *closure = lov_closure_get(env, lock);
 623         int i;
 624         int result;
 625         enum cl_lock_state minstate;
 626
 627         ENTRY;
 628
 629         for (result = 0, minstate = CLS_FREEING, i = 0; i < lck->lls_nr; ++i) {
 630                 int rc;
 631                 struct lovsub_lock     *sub;
 632                 struct lov_lock_sub    *lls;
 633                 struct cl_lock         *sublock;
 634                 struct lov_sublock_env *subenv;
 635
 636                 if (lock->cll_state != CLS_QUEUING) {
 637                         /*
 638                          * Lock might have left QUEUING state if previous
 639                          * iteration released its mutex. Stop enqueing in this
 640                          * case and let the upper layer to decide what to do.
 641                          */
 642                         LASSERT(i > 0 && result != 0);
 643                         break;
 644                 }
 645
 646                 lls = &lck->lls_sub[i];
 647                 sub = lls->sub_lock;
 648                 /*
 649                  * Sub-lock might have been canceled, while top-lock was
 650                  * cached.
 651                  */
 652                 if (sub == NULL) {
 653                         result = lov_sublock_fill(env, lock, io, lck, i);
 654                         /* lov_sublock_fill() released @lock mutex,
 655                          * restart. */
 656                         break;
 657                 }
 658                 sublock = sub->lss_cl.cls_lock;
 659                 rc = lov_sublock_lock(env, lck, lls, closure, &subenv);
 660                 if (rc == 0) {
 661                         lov_sublock_hold(env, lck, i);
 662                         rc = lov_lock_enqueue_one(subenv->lse_env, lck, sublock,
 663                                                   subenv->lse_io, enqflags,
 664                                                   i == lck->lls_nr - 1);
 665                         minstate = min(minstate, sublock->cll_state);
 666                         if (rc == CLO_WAIT) {
 667                                 switch (sublock->cll_state) {
 668                                 case CLS_QUEUING:
 669                                         /* take recursive mutex, the lock is
 670                                          * released in lov_lock_enqueue_wait.
 671                                          */
 672                                         cl_lock_mutex_get(env, sublock);
 673                                         lov_sublock_unlock(env, sub, closure,
 674                                                            subenv);
 675                                         rc = lov_lock_enqueue_wait(env, lck,
 676                                                                    sublock);
 677                                         break;
 678                                 case CLS_CACHED:
 679                                         rc = lov_sublock_release(env, lck, i,
 680                                                                  1, rc);
 681                                 default:
 682                                         lov_sublock_unlock(env, sub, closure,
 683                                                            subenv);
 684                                         break;
 685                                 }
 686                         } else {
 687                                 LASSERT(sublock->cll_conflict == NULL);
 688                                 lov_sublock_unlock(env, sub, closure, subenv);
 689                         }
 690                 }
 691                 result = lov_subresult(result, rc);
 692                 if (result != 0)
 693                         break;
 694         }
 695         cl_lock_closure_fini(closure);
 696         RETURN(result ?: minstate >= CLS_ENQUEUED ? 0 : CLO_WAIT);
 697 }
 698
 699 static int lov_lock_unuse(const struct lu_env *env,
 700                           const struct cl_lock_slice *slice)
 701 {
 702         struct lov_lock        *lck     = cl2lov_lock(slice);
 703         struct cl_lock_closure *closure = lov_closure_get(env, slice->cls_lock);
 704         int i;
 705         int result;
 706
 707         ENTRY;
 708
 709         for (result = 0, i = 0; i < lck->lls_nr; ++i) {
 710                 int rc;
 711                 struct lovsub_lock     *sub;
 712                 struct cl_lock         *sublock;
 713                 struct lov_lock_sub    *lls;
 714                 struct lov_sublock_env *subenv;
 715
 716                 /* top-lock state cannot change concurrently, because single
 717                  * thread (one that released the last hold) carries unlocking
 718                  * to the completion. */
 719                 LASSERT(slice->cls_lock->cll_state == CLS_INTRANSIT);
 720                 lls = &lck->lls_sub[i];
 721                 sub = lls->sub_lock;
 722                 if (sub == NULL)
 723                         continue;
 724
 725                 sublock = sub->lss_cl.cls_lock;
 726                 rc = lov_sublock_lock(env, lck, lls, closure, &subenv);
 727                 if (rc == 0) {
 728                         if (lls->sub_flags & LSF_HELD) {
 729                                 LASSERT(sublock->cll_state == CLS_HELD);
 730                                 rc = cl_unuse_try(subenv->lse_env, sublock);
 731                                 rc = lov_sublock_release(env, lck, i, 0, rc);
 732                         }
 733                         lov_sublock_unlock(env, sub, closure, subenv);
 734                 }
 735                 result = lov_subresult(result, rc);
 736         }
 737
 738         if (result == 0 && lck->lls_cancel_race) {
 739                 lck->lls_cancel_race = 0;
 740                 result = -ESTALE;
 741         }
 742         cl_lock_closure_fini(closure);
 743         RETURN(result);
 744 }
 745
 746
 747 static void lov_lock_cancel(const struct lu_env *env,
 748                            const struct cl_lock_slice *slice)
 749 {
 750         struct lov_lock        *lck     = cl2lov_lock(slice);
 751         struct cl_lock_closure *closure = lov_closure_get(env, slice->cls_lock);
 752         int i;
 753         int result;
 754
 755         ENTRY;
 756
 757         for (result = 0, i = 0; i < lck->lls_nr; ++i) {
 758                 int rc;
 759                 struct lovsub_lock     *sub;
 760                 struct cl_lock         *sublock;
 761                 struct lov_lock_sub    *lls;
 762                 struct lov_sublock_env *subenv;
 763
 764                 /* top-lock state cannot change concurrently, because single
 765                  * thread (one that released the last hold) carries unlocking
 766                  * to the completion. */
 767                 lls = &lck->lls_sub[i];
 768                 sub = lls->sub_lock;
 769                 if (sub == NULL)
 770                         continue;
 771
 772                 sublock = sub->lss_cl.cls_lock;
 773                 rc = lov_sublock_lock(env, lck, lls, closure, &subenv);
 774                 if (rc == 0) {
 775                         if (!(lls->sub_flags & LSF_HELD)) {
 776                                 lov_sublock_unlock(env, sub, closure, subenv);
 777                                 continue;
 778                         }
 779
 780                         switch(sublock->cll_state) {
 781                         case CLS_HELD:
 782                                 rc = cl_unuse_try(subenv->lse_env,
 783                                                   sublock);
 784                                 lov_sublock_release(env, lck, i, 0, 0);
 785                                 break;
 786                         case CLS_ENQUEUED:
 787                                 /* TODO: it's not a good idea to cancel this
 788                                  * lock because it's innocent. But it's
 789                                  * acceptable. The better way would be to
 790                                  * define a new lock method to unhold the
 791                                  * dlm lock. */
 792                                 cl_lock_cancel(env, sublock);
 793                         default:
 794                                 lov_sublock_release(env, lck, i, 1, 0);
 795                                 break;
 796                         }
 797                         lov_sublock_unlock(env, sub, closure, subenv);
 798                 }
 799
 800                 if (rc == CLO_REPEAT) {
 801                         --i;
 802                         continue;
 803                 }
 804
 805                 result = lov_subresult(result, rc);
 806         }
 807
 808         if (result)
 809                 CL_LOCK_DEBUG(D_ERROR, env, slice->cls_lock,
 810                               "lov_lock_cancel fails with %d.\n", result);
 811
 812         cl_lock_closure_fini(closure);
 813 }
 814
 815 static int lov_lock_wait(const struct lu_env *env,
 816                          const struct cl_lock_slice *slice)
 817 {
 818         struct lov_lock        *lck     = cl2lov_lock(slice);
 819         struct cl_lock_closure *closure = lov_closure_get(env, slice->cls_lock);
 820         enum cl_lock_state      minstate;
 821         int                     result;
 822         int                     i;
 823
 824         ENTRY;
 825
 826         for (result = 0, minstate = CLS_FREEING, i = 0; i < lck->lls_nr; ++i) {
 827                 int rc;
 828                 struct lovsub_lock     *sub;
 829                 struct cl_lock         *sublock;
 830                 struct lov_lock_sub    *lls;
 831                 struct lov_sublock_env *subenv;
 832
 833                 lls = &lck->lls_sub[i];
 834                 sub = lls->sub_lock;
 835                 LASSERT(sub != NULL);
 836                 sublock = sub->lss_cl.cls_lock;
 837                 rc = lov_sublock_lock(env, lck, lls, closure, &subenv);
 838                 if (rc == 0) {
 839                         LASSERT(sublock->cll_state >= CLS_ENQUEUED);
 840                         if (sublock->cll_state < CLS_HELD)
 841                                 rc = cl_wait_try(env, sublock);
 842
 843                         minstate = min(minstate, sublock->cll_state);
 844                         lov_sublock_unlock(env, sub, closure, subenv);
 845                 }
 846                 result = lov_subresult(result, rc);
 847                 if (result != 0)
 848                         break;
 849         }
 850         cl_lock_closure_fini(closure);
 851         RETURN(result ?: minstate >= CLS_HELD ? 0 : CLO_WAIT);
 852 }
 853
 854 static int lov_lock_use(const struct lu_env *env,
 855                         const struct cl_lock_slice *slice)
 856 {
 857         struct lov_lock        *lck     = cl2lov_lock(slice);
 858         struct cl_lock_closure *closure = lov_closure_get(env, slice->cls_lock);
 859         int                     result;
 860         int                     i;
 861
 862         LASSERT(slice->cls_lock->cll_state == CLS_INTRANSIT);
 863         ENTRY;
 864
 865         for (result = 0, i = 0; i < lck->lls_nr; ++i) {
 866                 int rc;
 867                 struct lovsub_lock     *sub;
 868                 struct cl_lock         *sublock;
 869                 struct lov_lock_sub    *lls;
 870                 struct lov_sublock_env *subenv;
 871
 872                 LASSERT(slice->cls_lock->cll_state == CLS_INTRANSIT);
 873
 874                 lls = &lck->lls_sub[i];
 875                 sub = lls->sub_lock;
 876                 if (sub == NULL) {
 877                         /*
 878                          * Sub-lock might have been canceled, while top-lock was
 879                          * cached.
 880                          */
 881                         result = -ESTALE;
 882                         break;
 883                 }
 884
 885                 sublock = sub->lss_cl.cls_lock;
 886                 rc = lov_sublock_lock(env, lck, lls, closure, &subenv);
 887                 if (rc == 0) {
 888                         LASSERT(sublock->cll_state != CLS_FREEING);
 889                         lov_sublock_hold(env, lck, i);
 890                         if (sublock->cll_state == CLS_CACHED) {
 891                                 rc = cl_use_try(subenv->lse_env, sublock, 0);
 892                                 if (rc != 0)
 893                                         rc = lov_sublock_release(env, lck,
 894                                                                  i, 1, rc);
 895                         }
 896                         lov_sublock_unlock(env, sub, closure, subenv);
 897                 }
 898                 result = lov_subresult(result, rc);
 899                 if (result != 0)
 900                         break;
 901         }
 902
 903         if (lck->lls_cancel_race) {
 904                 /*
 905                  * If there is unlocking happened at the same time, then
 906                  * sublock_lock state should be FREEING, and lov_sublock_lock
 907                  * should return CLO_REPEAT. In this case, it should return
 908                  * ESTALE, and up layer should reset the lock state to be NEW.
 909                  */
 910                 lck->lls_cancel_race = 0;
 911                 LASSERT(result != 0);
 912                 result = -ESTALE;
 913         }
 914         cl_lock_closure_fini(closure);
 915         RETURN(result);
 916 }
 917
 918 #if 0
 919 static int lock_lock_multi_match()
 920 {
 921         struct cl_lock          *lock    = slice->cls_lock;
 922         struct cl_lock_descr    *subneed = &lov_env_info(env)->lti_ldescr;
 923         struct lov_object       *loo     = cl2lov(lov->lls_cl.cls_obj);
 924         struct lov_layout_raid0 *r0      = lov_r0(loo);
 925         struct lov_lock_sub     *sub;
 926         struct cl_object        *subobj;
 927         obd_off  fstart;
 928         obd_off  fend;
 929         obd_off  start;
 930         obd_off  end;
 931         int i;
 932
 933         fstart = cl_offset(need->cld_obj, need->cld_start);
 934         fend   = cl_offset(need->cld_obj, need->cld_end + 1) - 1;
 935         subneed->cld_mode = need->cld_mode;
 936         cl_lock_mutex_get(env, lock);
 937         for (i = 0; i < lov->lls_nr; ++i) {
 938                 sub = &lov->lls_sub[i];
 939                 if (sub->sub_lock == NULL)
 940                         continue;
 941                 subobj = sub->sub_descr.cld_obj;
 942                 if (!lov_stripe_intersects(r0->lo_lsm, sub->sub_stripe,
 943                                            fstart, fend, &start, &end))
 944                         continue;
 945                 subneed->cld_start = cl_index(subobj, start);
 946                 subneed->cld_end   = cl_index(subobj, end);
 947                 subneed->cld_obj   = subobj;
 948                 if (!cl_lock_ext_match(&sub->sub_got, subneed)) {
 949                         result = 0;
 950                         break;
 951                 }
 952         }
 953         cl_lock_mutex_put(env, lock);
 954 }
 955 #endif
 956
 957 /**
 958  * Check if the extent region \a descr is covered by \a child against the
 959  * specific \a stripe.
 960  */
 961 static int lov_lock_stripe_is_matching(const struct lu_env *env,
 962                                        struct lov_object *lov, int stripe,
 963                                        const struct cl_lock_descr *child,
 964                                        const struct cl_lock_descr *descr)
 965 {
 966         struct lov_stripe_md *lsm = lov_r0(lov)->lo_lsm;
 967         obd_off start;
 968         obd_off end;
 969         int result;
 970
 971         if (lov_r0(lov)->lo_nr == 1)
 972                 return cl_lock_ext_match(child, descr);
 973
 974         /*
 975          * For a multi-stripes object:
 976          * - make sure the descr only covers child's stripe, and
 977          * - check if extent is matching.
 978          */
 979         start = cl_offset(&lov->lo_cl, descr->cld_start);
 980         end   = cl_offset(&lov->lo_cl, descr->cld_end + 1) - 1;
 981         result = end - start <= lsm->lsm_stripe_size &&
 982                  stripe == lov_stripe_number(lsm, start) &&
 983                  stripe == lov_stripe_number(lsm, end);
 984         if (result) {
 985                 struct cl_lock_descr *subd = &lov_env_info(env)->lti_ldescr;
 986                 obd_off sub_start;
 987                 obd_off sub_end;
 988
 989                 subd->cld_obj  = NULL;   /* don't need sub object at all */
 990                 subd->cld_mode = descr->cld_mode;
 991                 subd->cld_gid  = descr->cld_gid;
 992                 result = lov_stripe_intersects(lsm, stripe, start, end,
 993                                                &sub_start, &sub_end);
 994                 LASSERT(result);
 995                 subd->cld_start = cl_index(child->cld_obj, sub_start);
 996                 subd->cld_end   = cl_index(child->cld_obj, sub_end);
 997                 result = cl_lock_ext_match(child, subd);
 998         }
 999         return result;
1000 }
1001
1002 /**
1003  * An implementation of cl_lock_operations::clo_fits_into() method.
1004  *
1005  * Checks whether a lock (given by \a slice) is suitable for \a
1006  * io. Multi-stripe locks can be used only for "quick" io, like truncate, or
1007  * O_APPEND write.
1008  *
1009  * \see ccc_lock_fits_into().
1010  */
1011 static int lov_lock_fits_into(const struct lu_env *env,
1012                               const struct cl_lock_slice *slice,
1013                               const struct cl_lock_descr *need,
1014                               const struct cl_io *io)
1015 {
1016         struct lov_lock   *lov = cl2lov_lock(slice);
1017         struct lov_object *obj = cl2lov(slice->cls_obj);
1018         int result;
1019
1020         LASSERT(cl_object_same(need->cld_obj, slice->cls_obj));
1021         LASSERT(lov->lls_nr > 0);
1022
1023         ENTRY;
1024
1025         if (need->cld_mode == CLM_GROUP)
1026                 /*
1027                  * always allow to match group lock.
1028                  */
1029                 result = cl_lock_ext_match(&lov->lls_orig, need);
1030         else if (lov->lls_nr == 1) {
1031                 struct cl_lock_descr *got = &lov->lls_sub[0].sub_got;
1032                 result = lov_lock_stripe_is_matching(env,
1033                                                      cl2lov(slice->cls_obj),
1034                                                      lov->lls_sub[0].sub_stripe,
1035                                                      got, need);
1036         } else if (io->ci_type != CIT_TRUNC && io->ci_type != CIT_MISC &&
1037                    !cl_io_is_append(io) && need->cld_mode != CLM_PHANTOM)
1038                 /*
1039                  * Multi-stripe locks are only suitable for `quick' IO and for
1040                  * glimpse.
1041                  */
1042                 result = 0;
1043         else
1044                 /*
1045                  * Most general case: multi-stripe existing lock, and
1046                  * (potentially) multi-stripe @need lock. Check that @need is
1047                  * covered by @lov's sub-locks.
1048                  *
1049                  * For now, ignore lock expansions made by the server, and
1050                  * match against original lock extent.
1051                  */
1052                 result = cl_lock_ext_match(&lov->lls_orig, need);
1053         CDEBUG(D_DLMTRACE, DDESCR"/"DDESCR" %i %i/%i: %i\n",
1054                PDESCR(&lov->lls_orig), PDESCR(&lov->lls_sub[0].sub_got),
1055                lov->lls_sub[0].sub_stripe, lov->lls_nr, lov_r0(obj)->lo_nr,
1056                result);
1057         RETURN(result);
1058 }
1059
1060 void lov_lock_unlink(const struct lu_env *env,
1061                      struct lov_lock_link *link, struct lovsub_lock *sub)
1062 {
1063         struct lov_lock *lck    = link->lll_super;
1064         struct cl_lock  *parent = lck->lls_cl.cls_lock;
1065
1066         LASSERT(cl_lock_is_mutexed(parent));
1067         LASSERT(cl_lock_is_mutexed(sub->lss_cl.cls_lock));
1068         ENTRY;
1069
1070         list_del_init(&link->lll_list);
1071         LASSERT(lck->lls_sub[link->lll_idx].sub_lock == sub);
1072         /* yank this sub-lock from parent's array */
1073         lck->lls_sub[link->lll_idx].sub_lock = NULL;
1074         LASSERT(lck->lls_nr_filled > 0);
1075         lck->lls_nr_filled--;
1076         lu_ref_del(&parent->cll_reference, "lov-child", sub->lss_cl.cls_lock);
1077         cl_lock_put(env, parent);
1078         OBD_SLAB_FREE_PTR(link, lov_lock_link_kmem);
1079         EXIT;
1080 }
1081
1082 struct lov_lock_link *lov_lock_link_find(const struct lu_env *env,
1083                                          struct lov_lock *lck,
1084                                          struct lovsub_lock *sub)
1085 {
1086         struct lov_lock_link *scan;
1087
1088         LASSERT(cl_lock_is_mutexed(sub->lss_cl.cls_lock));
1089         ENTRY;
1090
1091         list_for_each_entry(scan, &sub->lss_parents, lll_list) {
1092                 if (scan->lll_super == lck)
1093                         RETURN(scan);
1094         }
1095         RETURN(NULL);
1096 }
1097
1098 /**
1099  * An implementation of cl_lock_operations::clo_delete() method. This is
1100  * invoked for "top-to-bottom" delete, when lock destruction starts from the
1101  * top-lock, e.g., as a result of inode destruction.
1102  *
1103  * Unlinks top-lock from all its sub-locks. Sub-locks are not deleted there:
1104  * this is done separately elsewhere:
1105  *
1106  *     - for inode destruction, lov_object_delete() calls cl_object_kill() for
1107  *       each sub-object, purging its locks;
1108  *
1109  *     - in other cases (e.g., a fatal error with a top-lock) sub-locks are
1110  *       left in the cache.
1111  */
1112 static void lov_lock_delete(const struct lu_env *env,
1113                             const struct cl_lock_slice *slice)
1114 {
1115         struct lov_lock        *lck     = cl2lov_lock(slice);
1116         struct cl_lock_closure *closure = lov_closure_get(env, slice->cls_lock);
1117         int i;
1118
1119         LASSERT(slice->cls_lock->cll_state == CLS_FREEING);
1120         ENTRY;
1121
1122         for (i = 0; i < lck->lls_nr; ++i) {
1123                 struct lov_lock_sub *lls;
1124                 struct lovsub_lock  *lsl;
1125                 struct cl_lock      *sublock;
1126                 int rc;
1127
1128                 lls = &lck->lls_sub[i];
1129                 lsl = lls->sub_lock;
1130                 if (lsl == NULL)
1131                         continue;
1132
1133                 sublock = lsl->lss_cl.cls_lock;
1134                 rc = lov_sublock_lock(env, lck, lls, closure, NULL);
1135                 if (rc == 0) {
1136                         if (lls->sub_flags & LSF_HELD)
1137                                 lov_sublock_release(env, lck, i, 1, 0);
1138                         if (sublock->cll_state < CLS_FREEING) {
1139                                 struct lov_lock_link *link;
1140
1141                                 link = lov_lock_link_find(env, lck, lsl);
1142                                 LASSERT(link != NULL);
1143                                 lov_lock_unlink(env, link, lsl);
1144                                 LASSERT(lck->lls_sub[i].sub_lock == NULL);
1145                         }
1146                         lov_sublock_unlock(env, lsl, closure, NULL);
1147                 } else if (rc == CLO_REPEAT) {
1148                         --i; /* repeat with this lock */
1149                 } else {
1150                         CL_LOCK_DEBUG(D_ERROR, env, sublock,
1151                                       "Cannot get sub-lock for delete: %i\n",
1152                                       rc);
1153                 }
1154         }
1155         cl_lock_closure_fini(closure);
1156         EXIT;
1157 }
1158
1159 static int lov_lock_print(const struct lu_env *env, void *cookie,
1160                           lu_printer_t p, const struct cl_lock_slice *slice)
1161 {
1162         struct lov_lock *lck = cl2lov_lock(slice);
1163         int              i;
1164
1165         (*p)(env, cookie, "%d\n", lck->lls_nr);
1166         for (i = 0; i < lck->lls_nr; ++i) {
1167                 struct lov_lock_sub *sub;
1168
1169                 sub = &lck->lls_sub[i];
1170                 (*p)(env, cookie, "    %d %x: ", i, sub->sub_flags);
1171                 if (sub->sub_lock != NULL)
1172                         cl_lock_print(env, cookie, p,
1173                                       sub->sub_lock->lss_cl.cls_lock);
1174                 else
1175                         (*p)(env, cookie, "---\n");
1176         }
1177         return 0;
1178 }
1179
1180 static const struct cl_lock_operations lov_lock_ops = {
1181         .clo_fini      = lov_lock_fini,
1182         .clo_enqueue   = lov_lock_enqueue,
1183         .clo_wait      = lov_lock_wait,
1184         .clo_use       = lov_lock_use,
1185         .clo_unuse     = lov_lock_unuse,
1186         .clo_cancel    = lov_lock_cancel,
1187         .clo_fits_into = lov_lock_fits_into,
1188         .clo_delete    = lov_lock_delete,
1189         .clo_print     = lov_lock_print
1190 };
1191
1192 int lov_lock_init_raid0(const struct lu_env *env, struct cl_object *obj,
1193                         struct cl_lock *lock, const struct cl_io *io)
1194 {
1195         struct lov_lock *lck;
1196         int result;
1197
1198         ENTRY;
1199         OBD_SLAB_ALLOC_PTR_GFP(lck, lov_lock_kmem, CFS_ALLOC_IO);
1200         if (lck != NULL) {
1201                 cl_lock_slice_add(lock, &lck->lls_cl, obj, &lov_lock_ops);
1202                 result = lov_lock_sub_init(env, lck, io);
1203         } else
1204                 result = -ENOMEM;
1205         RETURN(result);
1206 }
1207
1208 static struct cl_lock_closure *lov_closure_get(const struct lu_env *env,
1209                                                struct cl_lock *parent)
1210 {
1211         struct cl_lock_closure *closure;
1212
1213         closure = &lov_env_info(env)->lti_closure;
1214         LASSERT(list_empty(&closure->clc_list));
1215         cl_lock_closure_init(env, closure, parent, 1);
1216         return closure;
1217 }
1218
1219
1220 /** @} lov */