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