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 (!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                         struct lov_lock_link *link;
 221                         /*
 222                          * we could race with lock deletion which temporarily
 223                          * put the lock in freeing state, bug 19080.
 224                          */
 225                         LASSERT(!(lls->sub_flags & LSF_HELD));
 226
 227                         link = lov_lock_link_find(env, lck, sublock);
 228                         LASSERT(link != NULL);
 229                         lov_lock_unlink(env, link, sublock);
 230                         lov_sublock_unlock(env, sublock, closure, NULL);
 231                         lck->lls_cancel_race = 1;
 232                         result = CLO_REPEAT;
 233                 } else if (lsep) {
 234                         struct lov_sublock_env *subenv;
 235                         subenv = lov_sublock_env_get(env, parent, lls);
 236                         if (IS_ERR(subenv)) {
 237                                 lov_sublock_unlock(env, sublock,
 238                                                    closure, NULL);
 239                                 result = PTR_ERR(subenv);
 240                         } else {
 241                                 *lsep = subenv;
 242                         }
 243                 }
 244         }
 245         RETURN(result);
 246 }
 247
 248 /**
 249  * Updates the result of a top-lock operation from a result of sub-lock
 250  * sub-operations. Top-operations like lov_lock_{enqueue,use,unuse}() iterate
 251  * over sub-locks and lov_subresult() is used to calculate return value of a
 252  * top-operation. To this end, possible return values of sub-operations are
 253  * ordered as
 254  *
 255  *     - 0                  success
 256  *     - CLO_WAIT           wait for event
 257  *     - CLO_REPEAT         repeat top-operation
 258  *     - -ne                fundamental error
 259  *
 260  * Top-level return code can only go down through this list. CLO_REPEAT
 261  * overwrites CLO_WAIT, because lock mutex was released and sleeping condition
 262  * has to be rechecked by the upper layer.
 263  */
 264 static int lov_subresult(int result, int rc)
 265 {
 266         int result_rank;
 267         int rc_rank;
 268
 269         LASSERT(result <= 0 || result == CLO_REPEAT || result == CLO_WAIT);
 270         LASSERT(rc <= 0 || rc == CLO_REPEAT || rc == CLO_WAIT);
 271         CLASSERT(CLO_WAIT < CLO_REPEAT);
 272
 273         ENTRY;
 274
 275         /* calculate ranks in the ordering above */
 276         result_rank = result < 0 ? 1 + CLO_REPEAT : result;
 277         rc_rank = rc < 0 ? 1 + CLO_REPEAT : rc;
 278
 279         if (result_rank < rc_rank)
 280                 result = rc;
 281         RETURN(result);
 282 }
 283
 284 /**
 285  * Creates sub-locks for a given lov_lock for the first time.
 286  *
 287  * Goes through all sub-objects of top-object, and creates sub-locks on every
 288  * sub-object intersecting with top-lock extent. This is complicated by the
 289  * fact that top-lock (that is being created) can be accessed concurrently
 290  * through already created sub-locks (possibly shared with other top-locks).
 291  */
 292 static int lov_lock_sub_init(const struct lu_env *env,
 293                              struct lov_lock *lck, const struct cl_io *io)
 294 {
 295         int result = 0;
 296         int i;
 297         int nr;
 298         obd_off start;
 299         obd_off end;
 300         obd_off file_start;
 301         obd_off file_end;
 302
 303         struct lov_object       *loo    = cl2lov(lck->lls_cl.cls_obj);
 304         struct lov_layout_raid0 *r0     = lov_r0(loo);
 305         struct cl_lock          *parent = lck->lls_cl.cls_lock;
 306
 307         ENTRY;
 308
 309         lck->lls_orig = parent->cll_descr;
 310         file_start = cl_offset(lov2cl(loo), parent->cll_descr.cld_start);
 311         file_end   = cl_offset(lov2cl(loo), parent->cll_descr.cld_end + 1) - 1;
 312
 313         for (i = 0, nr = 0; i < r0->lo_nr; i++) {
 314                 /*
 315                  * XXX for wide striping smarter algorithm is desirable,
 316                  * breaking out of the loop, early.
 317                  */
 318                 if (lov_stripe_intersects(r0->lo_lsm, i,
 319                                           file_start, file_end, &start, &end))
 320                         nr++;
 321         }
 322         LASSERT(nr > 0);
 323         OBD_ALLOC(lck->lls_sub, nr * sizeof lck->lls_sub[0]);
 324         if (lck->lls_sub == NULL)
 325                 RETURN(-ENOMEM);
 326
 327         lck->lls_nr = nr;
 328         /*
 329          * First, fill in sub-lock descriptions in
 330          * lck->lls_sub[].sub_descr. They are used by lov_sublock_alloc()
 331          * (called below in this function, and by lov_lock_enqueue()) to
 332          * create sub-locks. At this moment, no other thread can access
 333          * top-lock.
 334          */
 335         for (i = 0, nr = 0; i < r0->lo_nr; ++i) {
 336                 if (lov_stripe_intersects(r0->lo_lsm, i,
 337                                           file_start, file_end, &start, &end)) {
 338                         struct cl_lock_descr *descr;
 339
 340                         descr = &lck->lls_sub[nr].sub_descr;
 341
 342                         LASSERT(descr->cld_obj == NULL);
 343                         descr->cld_obj   = lovsub2cl(r0->lo_sub[i]);
 344                         descr->cld_start = cl_index(descr->cld_obj, start);
 345                         descr->cld_end   = cl_index(descr->cld_obj, end);
 346                         descr->cld_mode  = parent->cll_descr.cld_mode;
 347                         descr->cld_gid   = parent->cll_descr.cld_gid;
 348                         /* XXX has no effect */
 349                         lck->lls_sub[nr].sub_got = *descr;
 350                         lck->lls_sub[nr].sub_stripe = i;
 351                         nr++;
 352                 }
 353         }
 354         LASSERT(nr == lck->lls_nr);
 355         /*
 356          * Then, create sub-locks. Once at least one sub-lock was created,
 357          * top-lock can be reached by other threads.
 358          */
 359         for (i = 0; i < lck->lls_nr; ++i) {
 360                 struct cl_lock       *sublock;
 361                 struct lov_lock_link *link;
 362
 363                 if (lck->lls_sub[i].sub_lock == NULL) {
 364                         sublock = lov_sublock_alloc(env, io, lck, i, &link);
 365                         if (IS_ERR(sublock)) {
 366                                 result = PTR_ERR(sublock);
 367                                 break;
 368                         }
 369                         cl_lock_mutex_get(env, sublock);
 370                         cl_lock_mutex_get(env, parent);
 371                         /*
 372                          * recheck under mutex that sub-lock wasn't created
 373                          * concurrently, and that top-lock is still alive.
 374                          */
 375                         if (lck->lls_sub[i].sub_lock == NULL &&
 376                             parent->cll_state < CLS_FREEING) {
 377                                 lov_sublock_adopt(env, lck, sublock, i, link);
 378                                 cl_lock_mutex_put(env, parent);
 379                         } else {
 380                                 OBD_SLAB_FREE_PTR(link, lov_lock_link_kmem);
 381                                 cl_lock_mutex_put(env, parent);
 382                                 cl_lock_unhold(env, sublock,
 383                                                "lov-parent", parent);
 384                         }
 385                         cl_lock_mutex_put(env, sublock);
 386                 }
 387         }
 388         /*
 389          * Some sub-locks can be missing at this point. This is not a problem,
 390          * because enqueue will create them anyway. Main duty of this function
 391          * is to fill in sub-lock descriptions in a race free manner.
 392          */
 393         RETURN(result);
 394 }
 395
 396 static int lov_sublock_release(const struct lu_env *env, struct lov_lock *lck,
 397                                int i, int deluser, int rc)
 398 {
 399         struct cl_lock *parent = lck->lls_cl.cls_lock;
 400
 401         LASSERT(cl_lock_is_mutexed(parent));
 402         ENTRY;
 403
 404         if (lck->lls_sub[i].sub_flags & LSF_HELD) {
 405                 struct cl_lock    *sublock;
 406                 int dying;
 407
 408                 LASSERT(lck->lls_sub[i].sub_lock != NULL);
 409                 sublock = lck->lls_sub[i].sub_lock->lss_cl.cls_lock;
 410                 LASSERT(cl_lock_is_mutexed(sublock));
 411
 412                 lck->lls_sub[i].sub_flags &= ~LSF_HELD;
 413                 if (deluser)
 414                         cl_lock_user_del(env, sublock);
 415                 /*
 416                  * If the last hold is released, and cancellation is pending
 417                  * for a sub-lock, release parent mutex, to avoid keeping it
 418                  * while sub-lock is being paged out.
 419                  */
 420                 dying = (sublock->cll_descr.cld_mode == CLM_PHANTOM ||
 421                          sublock->cll_descr.cld_mode == CLM_GROUP ||
 422                          (sublock->cll_flags & (CLF_CANCELPEND|CLF_DOOMED))) &&
 423                         sublock->cll_holds == 1;
 424                 if (dying)
 425                         cl_lock_mutex_put(env, parent);
 426                 cl_lock_unhold(env, sublock, "lov-parent", parent);
 427                 if (dying) {
 428                         cl_lock_mutex_get(env, parent);
 429                         rc = lov_subresult(rc, CLO_REPEAT);
 430                 }
 431                 /*
 432                  * From now on lck->lls_sub[i].sub_lock is a "weak" pointer,
 433                  * not backed by a reference on a
 434                  * sub-lock. lovsub_lock_delete() will clear
 435                  * lck->lls_sub[i].sub_lock under semaphores, just before
 436                  * sub-lock is destroyed.
 437                  */
 438         }
 439         RETURN(rc);
 440 }
 441
 442 static void lov_sublock_hold(const struct lu_env *env, struct lov_lock *lck,
 443                              int i)
 444 {
 445         struct cl_lock *parent = lck->lls_cl.cls_lock;
 446
 447         LASSERT(cl_lock_is_mutexed(parent));
 448         ENTRY;
 449
 450         if (!(lck->lls_sub[i].sub_flags & LSF_HELD)) {
 451                 struct cl_lock *sublock;
 452
 453                 LASSERT(lck->lls_sub[i].sub_lock != NULL);
 454                 sublock = lck->lls_sub[i].sub_lock->lss_cl.cls_lock;
 455                 LASSERT(cl_lock_is_mutexed(sublock));
 456                 LASSERT(sublock->cll_state != CLS_FREEING);
 457
 458                 lck->lls_sub[i].sub_flags |= LSF_HELD;
 459
 460                 cl_lock_get_trust(sublock);
 461                 cl_lock_hold_add(env, sublock, "lov-parent", parent);
 462                 cl_lock_user_add(env, sublock);
 463                 cl_lock_put(env, sublock);
 464         }
 465         EXIT;
 466 }
 467
 468 static void lov_lock_fini(const struct lu_env *env,
 469                           struct cl_lock_slice *slice)
 470 {
 471         struct lov_lock *lck;
 472         int i;
 473
 474         ENTRY;
 475         lck = cl2lov_lock(slice);
 476         LASSERT(lck->lls_nr_filled == 0);
 477         if (lck->lls_sub != NULL) {
 478                 for (i = 0; i < lck->lls_nr; ++i)
 479                         /*
 480                          * No sub-locks exists at this point, as sub-lock has
 481                          * a reference on its parent.
 482                          */
 483                         LASSERT(lck->lls_sub[i].sub_lock == NULL);
 484                 OBD_FREE(lck->lls_sub, lck->lls_nr * sizeof lck->lls_sub[0]);
 485         }
 486         OBD_SLAB_FREE_PTR(lck, lov_lock_kmem);
 487         EXIT;
 488 }
 489
 490 /**
 491  * Tries to advance a state machine of a given sub-lock toward enqueuing of
 492  * the top-lock.
 493  *
 494  * \retval 0 if state-transition can proceed
 495  * \retval -ve otherwise.
 496  */
 497 static int lov_lock_enqueue_one(const struct lu_env *env, struct lov_lock *lck,
 498                                 struct cl_lock *sublock,
 499                                 struct cl_io *io, __u32 enqflags, int last)
 500 {
 501         int result;
 502         ENTRY;
 503
 504         /* first, try to enqueue a sub-lock ... */
 505         result = cl_enqueue_try(env, sublock, io, enqflags);
 506         if (sublock->cll_state == CLS_ENQUEUED)
 507                 /* if it is enqueued, try to `wait' on it---maybe it's already
 508                  * granted */
 509                 result = cl_wait_try(env, sublock);
 510         /*
 511          * If CEF_ASYNC flag is set, then all sub-locks can be enqueued in
 512          * parallel, otherwise---enqueue has to wait until sub-lock is granted
 513          * before proceeding to the next one.
 514          */
 515         if (result == CLO_WAIT && sublock->cll_state <= CLS_HELD &&
 516             enqflags & CEF_ASYNC && !last)
 517                 result = 0;
 518         RETURN(result);
 519 }
 520
 521 /**
 522  * Helper function for lov_lock_enqueue() that creates missing sub-lock.
 523  */
 524 static int lov_sublock_fill(const struct lu_env *env, struct cl_lock *parent,
 525                             struct cl_io *io, struct lov_lock *lck, int idx)
 526 {
 527         struct lov_lock_link *link;
 528         struct cl_lock       *sublock;
 529         int                   result;
 530
 531         LASSERT(parent->cll_depth == 1);
 532         cl_lock_mutex_put(env, parent);
 533         sublock = lov_sublock_alloc(env, io, lck, idx, &link);
 534         if (!IS_ERR(sublock))
 535                 cl_lock_mutex_get(env, sublock);
 536         cl_lock_mutex_get(env, parent);
 537
 538         if (!IS_ERR(sublock)) {
 539                 if (parent->cll_state == CLS_QUEUING &&
 540                     lck->lls_sub[idx].sub_lock == NULL)
 541                         lov_sublock_adopt(env, lck, sublock, idx, link);
 542                 else {
 543                         OBD_SLAB_FREE_PTR(link, lov_lock_link_kmem);
 544                         /* other thread allocated sub-lock, or enqueue is no
 545                          * longer going on */
 546                         cl_lock_mutex_put(env, parent);
 547                         cl_lock_unhold(env, sublock, "lov-parent", parent);
 548                         cl_lock_mutex_get(env, parent);
 549                 }
 550                 cl_lock_mutex_put(env, sublock);
 551                 result = CLO_REPEAT;
 552         } else
 553                 result = PTR_ERR(sublock);
 554         return result;
 555 }
 556
 557 /**
 558  * Implementation of cl_lock_operations::clo_enqueue() for lov layer. This
 559  * function is rather subtle, as it enqueues top-lock (i.e., advances top-lock
 560  * state machine from CLS_QUEUING to CLS_ENQUEUED states) by juggling sub-lock
 561  * state machines in the face of sub-locks sharing (by multiple top-locks),
 562  * and concurrent sub-lock cancellations.
 563  */
 564 static int lov_lock_enqueue(const struct lu_env *env,
 565                             const struct cl_lock_slice *slice,
 566                             struct cl_io *io, __u32 enqflags)
 567 {
 568         struct cl_lock         *lock    = slice->cls_lock;
 569         struct lov_lock        *lck     = cl2lov_lock(slice);
 570         struct cl_lock_closure *closure = lov_closure_get(env, lock);
 571         int i;
 572         int result;
 573         enum cl_lock_state minstate;
 574
 575         ENTRY;
 576
 577         for (result = 0, minstate = CLS_FREEING, i = 0; i < lck->lls_nr; ++i) {
 578                 int rc;
 579                 struct lovsub_lock     *sub;
 580                 struct lov_lock_sub    *lls;
 581                 struct cl_lock         *sublock;
 582                 struct lov_sublock_env *subenv;
 583
 584                 if (lock->cll_state != CLS_QUEUING) {
 585                         /*
 586                          * Lock might have left QUEUING state if previous
 587                          * iteration released its mutex. Stop enqueing in this
 588                          * case and let the upper layer to decide what to do.
 589                          */
 590                         LASSERT(i > 0 && result != 0);
 591                         break;
 592                 }
 593
 594                 lls = &lck->lls_sub[i];
 595                 sub = lls->sub_lock;
 596                 /*
 597                  * Sub-lock might have been canceled, while top-lock was
 598                  * cached.
 599                  */
 600                 if (sub == NULL) {
 601                         result = lov_sublock_fill(env, lock, io, lck, i);
 602                         /* lov_sublock_fill() released @lock mutex,
 603                          * restart. */
 604                         break;
 605                 }
 606                 sublock = sub->lss_cl.cls_lock;
 607                 rc = lov_sublock_lock(env, lck, lls, closure, &subenv);
 608                 if (rc == 0) {
 609                         lov_sublock_hold(env, lck, i);
 610                         rc = lov_lock_enqueue_one(subenv->lse_env, lck, sublock,
 611                                                   subenv->lse_io, enqflags,
 612                                                   i == lck->lls_nr - 1);
 613                         minstate = min(minstate, sublock->cll_state);
 614                         /*
 615                          * Don't hold a sub-lock in CLS_CACHED state, see
 616                          * description for lov_lock::lls_sub.
 617                          */
 618                         if (sublock->cll_state > CLS_HELD)
 619                                 rc = lov_sublock_release(env, lck, i, 1, rc);
 620                         lov_sublock_unlock(env, sub, closure, subenv);
 621                 }
 622                 result = lov_subresult(result, rc);
 623                 if (result != 0)
 624                         break;
 625         }
 626         cl_lock_closure_fini(closure);
 627         RETURN(result ?: minstate >= CLS_ENQUEUED ? 0 : CLO_WAIT);
 628 }
 629
 630 static int lov_lock_unuse(const struct lu_env *env,
 631                           const struct cl_lock_slice *slice)
 632 {
 633         struct lov_lock        *lck     = cl2lov_lock(slice);
 634         struct cl_lock_closure *closure = lov_closure_get(env, slice->cls_lock);
 635         int i;
 636         int result;
 637
 638         ENTRY;
 639
 640         for (result = 0, i = 0; i < lck->lls_nr; ++i) {
 641                 int rc;
 642                 struct lovsub_lock     *sub;
 643                 struct cl_lock         *sublock;
 644                 struct lov_lock_sub    *lls;
 645                 struct lov_sublock_env *subenv;
 646
 647                 /* top-lock state cannot change concurrently, because single
 648                  * thread (one that released the last hold) carries unlocking
 649                  * to the completion. */
 650                 LASSERT(slice->cls_lock->cll_state == CLS_INTRANSIT);
 651                 lls = &lck->lls_sub[i];
 652                 sub = lls->sub_lock;
 653                 if (sub == NULL)
 654                         continue;
 655
 656                 sublock = sub->lss_cl.cls_lock;
 657                 rc = lov_sublock_lock(env, lck, lls, closure, &subenv);
 658                 if (rc == 0) {
 659                         if (lls->sub_flags & LSF_HELD) {
 660                                 LASSERT(sublock->cll_state == CLS_HELD);
 661                                 rc = cl_unuse_try(subenv->lse_env, sublock);
 662                                 if (rc != CLO_WAIT)
 663                                         rc = lov_sublock_release(env, lck,
 664                                                                  i, 0, rc);
 665                         }
 666                         lov_sublock_unlock(env, sub, closure, subenv);
 667                 }
 668                 result = lov_subresult(result, rc);
 669                 if (result < 0)
 670                         break;
 671         }
 672
 673         if (result == 0 && lck->lls_cancel_race) {
 674                 lck->lls_cancel_race = 0;
 675                 result = -ESTALE;
 676         }
 677         cl_lock_closure_fini(closure);
 678         RETURN(result);
 679 }
 680
 681 static int lov_lock_wait(const struct lu_env *env,
 682                          const struct cl_lock_slice *slice)
 683 {
 684         struct lov_lock        *lck     = cl2lov_lock(slice);
 685         struct cl_lock_closure *closure = lov_closure_get(env, slice->cls_lock);
 686         enum cl_lock_state      minstate;
 687         int                     result;
 688         int                     i;
 689
 690         ENTRY;
 691
 692         for (result = 0, minstate = CLS_FREEING, i = 0; i < lck->lls_nr; ++i) {
 693                 int rc;
 694                 struct lovsub_lock     *sub;
 695                 struct cl_lock         *sublock;
 696                 struct lov_lock_sub    *lls;
 697                 struct lov_sublock_env *subenv;
 698
 699                 lls = &lck->lls_sub[i];
 700                 sub = lls->sub_lock;
 701                 LASSERT(sub != NULL);
 702                 sublock = sub->lss_cl.cls_lock;
 703                 rc = lov_sublock_lock(env, lck, lls, closure, &subenv);
 704                 if (rc == 0) {
 705                         LASSERT(sublock->cll_state >= CLS_ENQUEUED);
 706                         if (sublock->cll_state < CLS_HELD)
 707                                 rc = cl_wait_try(env, sublock);
 708
 709                         minstate = min(minstate, sublock->cll_state);
 710                         lov_sublock_unlock(env, sub, closure, subenv);
 711                 }
 712                 result = lov_subresult(result, rc);
 713                 if (result != 0)
 714                         break;
 715         }
 716         cl_lock_closure_fini(closure);
 717         RETURN(result ?: minstate >= CLS_HELD ? 0 : CLO_WAIT);
 718 }
 719
 720 static int lov_lock_use(const struct lu_env *env,
 721                         const struct cl_lock_slice *slice)
 722 {
 723         struct lov_lock        *lck     = cl2lov_lock(slice);
 724         struct cl_lock_closure *closure = lov_closure_get(env, slice->cls_lock);
 725         int                     result;
 726         int                     i;
 727
 728         LASSERT(slice->cls_lock->cll_state == CLS_INTRANSIT);
 729         ENTRY;
 730
 731         for (result = 0, i = 0; i < lck->lls_nr; ++i) {
 732                 int rc;
 733                 struct lovsub_lock     *sub;
 734                 struct cl_lock         *sublock;
 735                 struct lov_lock_sub    *lls;
 736                 struct lov_sublock_env *subenv;
 737
 738                 LASSERT(slice->cls_lock->cll_state == CLS_INTRANSIT);
 739
 740                 lls = &lck->lls_sub[i];
 741                 sub = lls->sub_lock;
 742                 if (sub == NULL) {
 743                         /*
 744                          * Sub-lock might have been canceled, while top-lock was
 745                          * cached.
 746                          */
 747                         result = -ESTALE;
 748                         break;
 749                 }
 750
 751                 sublock = sub->lss_cl.cls_lock;
 752                 rc = lov_sublock_lock(env, lck, lls, closure, &subenv);
 753                 if (rc == 0) {
 754                         LASSERT(sublock->cll_state != CLS_FREEING);
 755                         lov_sublock_hold(env, lck, i);
 756                         if (sublock->cll_state == CLS_CACHED) {
 757                                 rc = cl_use_try(subenv->lse_env, sublock, 0);
 758                                 if (rc != 0)
 759                                         rc = lov_sublock_release(env, lck,
 760                                                                  i, 1, rc);
 761                         }
 762                         lov_sublock_unlock(env, sub, closure, subenv);
 763                 }
 764                 result = lov_subresult(result, rc);
 765                 if (result != 0)
 766                         break;
 767         }
 768
 769         if (lck->lls_cancel_race) {
 770                 /*
 771                  * If there is unlocking happened at the same time, then
 772                  * sublock_lock state should be FREEING, and lov_sublock_lock
 773                  * should return CLO_REPEAT. In this case, it should return
 774                  * ESTALE, and up layer should reset the lock state to be NEW.
 775                  */
 776                 lck->lls_cancel_race = 0;
 777                 LASSERT(result != 0);
 778                 result = -ESTALE;
 779         }
 780         cl_lock_closure_fini(closure);
 781         RETURN(result);
 782 }
 783
 784 #if 0
 785 static int lock_lock_multi_match()
 786 {
 787         struct cl_lock          *lock    = slice->cls_lock;
 788         struct cl_lock_descr    *subneed = &lov_env_info(env)->lti_ldescr;
 789         struct lov_object       *loo     = cl2lov(lov->lls_cl.cls_obj);
 790         struct lov_layout_raid0 *r0      = lov_r0(loo);
 791         struct lov_lock_sub     *sub;
 792         struct cl_object        *subobj;
 793         obd_off  fstart;
 794         obd_off  fend;
 795         obd_off  start;
 796         obd_off  end;
 797         int i;
 798
 799         fstart = cl_offset(need->cld_obj, need->cld_start);
 800         fend   = cl_offset(need->cld_obj, need->cld_end + 1) - 1;
 801         subneed->cld_mode = need->cld_mode;
 802         cl_lock_mutex_get(env, lock);
 803         for (i = 0; i < lov->lls_nr; ++i) {
 804                 sub = &lov->lls_sub[i];
 805                 if (sub->sub_lock == NULL)
 806                         continue;
 807                 subobj = sub->sub_descr.cld_obj;
 808                 if (!lov_stripe_intersects(r0->lo_lsm, sub->sub_stripe,
 809                                            fstart, fend, &start, &end))
 810                         continue;
 811                 subneed->cld_start = cl_index(subobj, start);
 812                 subneed->cld_end   = cl_index(subobj, end);
 813                 subneed->cld_obj   = subobj;
 814                 if (!cl_lock_ext_match(&sub->sub_got, subneed)) {
 815                         result = 0;
 816                         break;
 817                 }
 818         }
 819         cl_lock_mutex_put(env, lock);
 820 }
 821 #endif
 822
 823 /**
 824  * Check if the extent region \a descr is covered by \a child against the
 825  * specific \a stripe.
 826  */
 827 static int lov_lock_stripe_is_matching(const struct lu_env *env,
 828                                        struct lov_object *lov, int stripe,
 829                                        const struct cl_lock_descr *child,
 830                                        const struct cl_lock_descr *descr)
 831 {
 832         struct lov_stripe_md *lsm = lov_r0(lov)->lo_lsm;
 833         obd_off start;
 834         obd_off end;
 835         int result;
 836
 837         if (lov_r0(lov)->lo_nr == 1)
 838                 return cl_lock_ext_match(child, descr);
 839
 840         /*
 841          * For a multi-stripes object:
 842          * - make sure the descr only covers child's stripe, and
 843          * - check if extent is matching.
 844          */
 845         start = cl_offset(&lov->lo_cl, descr->cld_start);
 846         end   = cl_offset(&lov->lo_cl, descr->cld_end + 1) - 1;
 847         result = end - start <= lsm->lsm_stripe_size &&
 848                  stripe == lov_stripe_number(lsm, start) &&
 849                  stripe == lov_stripe_number(lsm, end);
 850         if (result) {
 851                 struct cl_lock_descr *subd = &lov_env_info(env)->lti_ldescr;
 852                 obd_off sub_start;
 853                 obd_off sub_end;
 854
 855                 subd->cld_obj  = NULL;   /* don't need sub object at all */
 856                 subd->cld_mode = descr->cld_mode;
 857                 subd->cld_gid  = descr->cld_gid;
 858                 result = lov_stripe_intersects(lsm, stripe, start, end,
 859                                                &sub_start, &sub_end);
 860                 LASSERT(result);
 861                 subd->cld_start = cl_index(child->cld_obj, sub_start);
 862                 subd->cld_end   = cl_index(child->cld_obj, sub_end);
 863                 result = cl_lock_ext_match(child, subd);
 864         }
 865         return result;
 866 }
 867
 868 /**
 869  * An implementation of cl_lock_operations::clo_fits_into() method.
 870  *
 871  * Checks whether a lock (given by \a slice) is suitable for \a
 872  * io. Multi-stripe locks can be used only for "quick" io, like truncate, or
 873  * O_APPEND write.
 874  *
 875  * \see ccc_lock_fits_into().
 876  */
 877 static int lov_lock_fits_into(const struct lu_env *env,
 878                               const struct cl_lock_slice *slice,
 879                               const struct cl_lock_descr *need,
 880                               const struct cl_io *io)
 881 {
 882         struct lov_lock   *lov = cl2lov_lock(slice);
 883         struct lov_object *obj = cl2lov(slice->cls_obj);
 884         int result;
 885
 886         LASSERT(cl_object_same(need->cld_obj, slice->cls_obj));
 887         LASSERT(lov->lls_nr > 0);
 888
 889         ENTRY;
 890
 891         if (need->cld_mode == CLM_GROUP)
 892                 /*
 893                  * always allow to match group lock.
 894                  */
 895                 result = cl_lock_ext_match(&lov->lls_orig, need);
 896         else if (lov->lls_nr == 1) {
 897                 struct cl_lock_descr *got = &lov->lls_sub[0].sub_got;
 898                 result = lov_lock_stripe_is_matching(env,
 899                                                      cl2lov(slice->cls_obj),
 900                                                      lov->lls_sub[0].sub_stripe,
 901                                                      got, need);
 902         } else if (io->ci_type != CIT_TRUNC && io->ci_type != CIT_MISC &&
 903                    !cl_io_is_append(io) && need->cld_mode != CLM_PHANTOM)
 904                 /*
 905                  * Multi-stripe locks are only suitable for `quick' IO and for
 906                  * glimpse.
 907                  */
 908                 result = 0;
 909         else
 910                 /*
 911                  * Most general case: multi-stripe existing lock, and
 912                  * (potentially) multi-stripe @need lock. Check that @need is
 913                  * covered by @lov's sub-locks.
 914                  *
 915                  * For now, ignore lock expansions made by the server, and
 916                  * match against original lock extent.
 917                  */
 918                 result = cl_lock_ext_match(&lov->lls_orig, need);
 919         CDEBUG(D_DLMTRACE, DDESCR"/"DDESCR" %i %i/%i: %i\n",
 920                PDESCR(&lov->lls_orig), PDESCR(&lov->lls_sub[0].sub_got),
 921                lov->lls_sub[0].sub_stripe, lov->lls_nr, lov_r0(obj)->lo_nr,
 922                result);
 923         RETURN(result);
 924 }
 925
 926 void lov_lock_unlink(const struct lu_env *env,
 927                      struct lov_lock_link *link, struct lovsub_lock *sub)
 928 {
 929         struct lov_lock *lck    = link->lll_super;
 930         struct cl_lock  *parent = lck->lls_cl.cls_lock;
 931
 932         LASSERT(cl_lock_is_mutexed(parent));
 933         LASSERT(cl_lock_is_mutexed(sub->lss_cl.cls_lock));
 934         ENTRY;
 935
 936         list_del_init(&link->lll_list);
 937         LASSERT(lck->lls_sub[link->lll_idx].sub_lock == sub);
 938         /* yank this sub-lock from parent's array */
 939         lck->lls_sub[link->lll_idx].sub_lock = NULL;
 940         LASSERT(lck->lls_nr_filled > 0);
 941         lck->lls_nr_filled--;
 942         lu_ref_del(&parent->cll_reference, "lov-child", sub->lss_cl.cls_lock);
 943         cl_lock_put(env, parent);
 944         OBD_SLAB_FREE_PTR(link, lov_lock_link_kmem);
 945         EXIT;
 946 }
 947
 948 struct lov_lock_link *lov_lock_link_find(const struct lu_env *env,
 949                                          struct lov_lock *lck,
 950                                          struct lovsub_lock *sub)
 951 {
 952         struct lov_lock_link *scan;
 953
 954         LASSERT(cl_lock_is_mutexed(sub->lss_cl.cls_lock));
 955         ENTRY;
 956
 957         list_for_each_entry(scan, &sub->lss_parents, lll_list) {
 958                 if (scan->lll_super == lck)
 959                         RETURN(scan);
 960         }
 961         RETURN(NULL);
 962 }
 963
 964 /**
 965  * An implementation of cl_lock_operations::clo_delete() method. This is
 966  * invoked for "top-to-bottom" delete, when lock destruction starts from the
 967  * top-lock, e.g., as a result of inode destruction.
 968  *
 969  * Unlinks top-lock from all its sub-locks. Sub-locks are not deleted there:
 970  * this is done separately elsewhere:
 971  *
 972  *     - for inode destruction, lov_object_delete() calls cl_object_kill() for
 973  *       each sub-object, purging its locks;
 974  *
 975  *     - in other cases (e.g., a fatal error with a top-lock) sub-locks are
 976  *       left in the cache.
 977  */
 978 static void lov_lock_delete(const struct lu_env *env,
 979                             const struct cl_lock_slice *slice)
 980 {
 981         struct lov_lock        *lck     = cl2lov_lock(slice);
 982         struct cl_lock_closure *closure = lov_closure_get(env, slice->cls_lock);
 983         int i;
 984
 985         LASSERT(slice->cls_lock->cll_state == CLS_FREEING);
 986         ENTRY;
 987
 988         for (i = 0; i < lck->lls_nr; ++i) {
 989                 struct lov_lock_sub *lls;
 990                 struct lovsub_lock  *lsl;
 991                 struct cl_lock      *sublock;
 992                 int rc;
 993
 994                 lls = &lck->lls_sub[i];
 995                 lsl = lls->sub_lock;
 996                 if (lsl == NULL)
 997                         continue;
 998
 999                 sublock = lsl->lss_cl.cls_lock;
1000                 rc = lov_sublock_lock(env, lck, lls, closure, NULL);
1001                 if (rc == 0) {
1002                         if (lls->sub_flags & LSF_HELD)
1003                                 lov_sublock_release(env, lck, i, 1, 0);
1004                         if (sublock->cll_state < CLS_FREEING) {
1005                                 struct lov_lock_link *link;
1006
1007                                 link = lov_lock_link_find(env, lck, lsl);
1008                                 LASSERT(link != NULL);
1009                                 lov_lock_unlink(env, link, lsl);
1010                                 LASSERT(lck->lls_sub[i].sub_lock == NULL);
1011                         }
1012                         lov_sublock_unlock(env, lsl, closure, NULL);
1013                 } else if (rc == CLO_REPEAT) {
1014                         --i; /* repeat with this lock */
1015                 } else {
1016                         CL_LOCK_DEBUG(D_ERROR, env, sublock,
1017                                       "Cannot get sub-lock for delete: %i\n",
1018                                       rc);
1019                 }
1020         }
1021         cl_lock_closure_fini(closure);
1022         EXIT;
1023 }
1024
1025 static int lov_lock_print(const struct lu_env *env, void *cookie,
1026                           lu_printer_t p, const struct cl_lock_slice *slice)
1027 {
1028         struct lov_lock *lck = cl2lov_lock(slice);
1029         int              i;
1030
1031         (*p)(env, cookie, "%d\n", lck->lls_nr);
1032         for (i = 0; i < lck->lls_nr; ++i) {
1033                 struct lov_lock_sub *sub;
1034
1035                 sub = &lck->lls_sub[i];
1036                 (*p)(env, cookie, "    %d %x: ", i, sub->sub_flags);
1037                 if (sub->sub_lock != NULL)
1038                         cl_lock_print(env, cookie, p,
1039                                       sub->sub_lock->lss_cl.cls_lock);
1040                 else
1041                         (*p)(env, cookie, "---\n");
1042         }
1043         return 0;
1044 }
1045
1046 static const struct cl_lock_operations lov_lock_ops = {
1047         .clo_fini      = lov_lock_fini,
1048         .clo_enqueue   = lov_lock_enqueue,
1049         .clo_wait      = lov_lock_wait,
1050         .clo_use       = lov_lock_use,
1051         .clo_unuse     = lov_lock_unuse,
1052         .clo_fits_into = lov_lock_fits_into,
1053         .clo_delete    = lov_lock_delete,
1054         .clo_print     = lov_lock_print
1055 };
1056
1057 int lov_lock_init_raid0(const struct lu_env *env, struct cl_object *obj,
1058                         struct cl_lock *lock, const struct cl_io *io)
1059 {
1060         struct lov_lock *lck;
1061         int result;
1062
1063         ENTRY;
1064         OBD_SLAB_ALLOC_PTR_GFP(lck, lov_lock_kmem, CFS_ALLOC_IO);
1065         if (lck != NULL) {
1066                 cl_lock_slice_add(lock, &lck->lls_cl, obj, &lov_lock_ops);
1067                 result = lov_lock_sub_init(env, lck, io);
1068         } else
1069                 result = -ENOMEM;
1070         RETURN(result);
1071 }
1072
1073 static struct cl_lock_closure *lov_closure_get(const struct lu_env *env,
1074                                                struct cl_lock *parent)
1075 {
1076         struct cl_lock_closure *closure;
1077
1078         closure = &lov_env_info(env)->lti_closure;
1079         LASSERT(list_empty(&closure->clc_list));
1080         cl_lock_closure_init(env, closure, parent, 1);
1081         return closure;
1082 }
1083
1084
1085 /** @} lov */