lustre/osc/osc_cache.c

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see
  18  * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
  19  *
  20  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  21  * CA 95054 USA or visit www.sun.com if you need additional information or
  22  * have any questions.
  23  *
  24  * GPL HEADER END
  25  */
  26 /*
  27  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  28  * Use is subject to license terms.
  29  *
  30  * Copyright (c) 2012, 2013, Intel Corporation.
  31  *
  32  */
  33 /*
  34  * This file is part of Lustre, http://www.lustre.org/
  35  * Lustre is a trademark of Sun Microsystems, Inc.
  36  *
  37  * osc cache management.
  38  *
  39  * Author: Jinshan Xiong <jinshan.xiong@whamcloud.com>
  40  */
  41
  42 #define DEBUG_SUBSYSTEM S_OSC
  43
  44 #include "osc_cl_internal.h"
  45 #include "osc_internal.h"
  46
  47 static int extent_debug; /* set it to be true for more debug */
  48
  49 static void osc_update_pending(struct osc_object *obj, int cmd, int delta);
  50 static int osc_extent_wait(const struct lu_env *env, struct osc_extent *ext,
  51                            int state);
  52 static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
  53                               struct osc_async_page *oap, int sent, int rc);
  54 static int osc_make_ready(const struct lu_env *env, struct osc_async_page *oap,
  55                           int cmd);
  56 static int osc_refresh_count(const struct lu_env *env,
  57                              struct osc_async_page *oap, int cmd);
  58 static int osc_io_unplug_async(const struct lu_env *env,
  59                                struct client_obd *cli, struct osc_object *osc);
  60 static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
  61                            unsigned int lost_grant);
  62
  63 static void osc_extent_tree_dump0(int level, struct osc_object *obj,
  64                                   const char *func, int line);
  65 #define osc_extent_tree_dump(lvl, obj) \
  66         osc_extent_tree_dump0(lvl, obj, __func__, __LINE__)
  67
  68 /** \addtogroup osc
  69  *  @{
  70  */
  71
  72 /* ------------------ osc extent ------------------ */
  73 static inline char *ext_flags(struct osc_extent *ext, char *flags)
  74 {
  75         char *buf = flags;
  76         *buf++ = ext->oe_rw ? 'r' : 'w';
  77         if (ext->oe_intree)
  78                 *buf++ = 'i';
  79         if (ext->oe_srvlock)
  80                 *buf++ = 's';
  81         if (ext->oe_hp)
  82                 *buf++ = 'h';
  83         if (ext->oe_urgent)
  84                 *buf++ = 'u';
  85         if (ext->oe_memalloc)
  86                 *buf++ = 'm';
  87         if (ext->oe_trunc_pending)
  88                 *buf++ = 't';
  89         if (ext->oe_fsync_wait)
  90                 *buf++ = 'Y';
  91         *buf = 0;
  92         return flags;
  93 }
  94
  95 static inline char list_empty_marker(cfs_list_t *list)
  96 {
  97         return cfs_list_empty(list) ? '-' : '+';
  98 }
  99
 100 #define EXTSTR       "[%lu -> %lu/%lu]"
 101 #define EXTPARA(ext) (ext)->oe_start, (ext)->oe_end, (ext)->oe_max_end
 102 static const char *oes_strings[] = {
 103         "inv", "active", "cache", "locking", "lockdone", "rpc", "trunc", NULL };
 104
 105 #define OSC_EXTENT_DUMP(lvl, extent, fmt, ...) do {                           \
 106         struct osc_extent *__ext = (extent);                                  \
 107         char __buf[16];                                                       \
 108                                                                               \
 109         CDEBUG(lvl,                                                           \
 110                 "extent %p@{" EXTSTR ", "                                     \
 111                 "[%d|%d|%c|%s|%s|%p], [%d|%d|%c|%c|%p|%u|%p]} " fmt,          \
 112                 /* ----- extent part 0 ----- */                               \
 113                 __ext, EXTPARA(__ext),                                        \
 114                 /* ----- part 1 ----- */                                      \
 115                 cfs_atomic_read(&__ext->oe_refc),                             \
 116                 cfs_atomic_read(&__ext->oe_users),                            \
 117                 list_empty_marker(&__ext->oe_link),                           \
 118                 oes_strings[__ext->oe_state], ext_flags(__ext, __buf),        \
 119                 __ext->oe_obj,                                                \
 120                 /* ----- part 2 ----- */                                      \
 121                 __ext->oe_grants, __ext->oe_nr_pages,                         \
 122                 list_empty_marker(&__ext->oe_pages),                          \
 123                 cfs_waitq_active(&__ext->oe_waitq) ? '+' : '-',               \
 124                 __ext->oe_osclock, __ext->oe_mppr, __ext->oe_owner,           \
 125                 /* ----- part 4 ----- */                                      \
 126                 ## __VA_ARGS__);                                              \
 127 } while (0)
 128
 129 #undef EASSERTF
 130 #define EASSERTF(expr, ext, fmt, args...) do {                          \
 131         if (!(expr)) {                                                  \
 132                 OSC_EXTENT_DUMP(D_ERROR, (ext), fmt, ##args);           \
 133                 osc_extent_tree_dump(D_ERROR, (ext)->oe_obj);           \
 134                 LASSERT(expr);                                          \
 135         }                                                               \
 136 } while (0)
 137
 138 #undef EASSERT
 139 #define EASSERT(expr, ext) EASSERTF(expr, ext, "\n")
 140
 141 static inline struct osc_extent *rb_extent(struct rb_node *n)
 142 {
 143         if (n == NULL)
 144                 return NULL;
 145
 146         return container_of(n, struct osc_extent, oe_node);
 147 }
 148
 149 static inline struct osc_extent *next_extent(struct osc_extent *ext)
 150 {
 151         if (ext == NULL)
 152                 return NULL;
 153
 154         LASSERT(ext->oe_intree);
 155         return rb_extent(rb_next(&ext->oe_node));
 156 }
 157
 158 static inline struct osc_extent *prev_extent(struct osc_extent *ext)
 159 {
 160         if (ext == NULL)
 161                 return NULL;
 162
 163         LASSERT(ext->oe_intree);
 164         return rb_extent(rb_prev(&ext->oe_node));
 165 }
 166
 167 static inline struct osc_extent *first_extent(struct osc_object *obj)
 168 {
 169         return rb_extent(rb_first(&obj->oo_root));
 170 }
 171
 172 /* object must be locked by caller. */
 173 static int osc_extent_sanity_check0(struct osc_extent *ext,
 174                                     const char *func, const int line)
 175 {
 176         struct osc_object *obj = ext->oe_obj;
 177         struct osc_async_page *oap;
 178         int page_count;
 179         int rc = 0;
 180
 181         if (!osc_object_is_locked(obj))
 182                 GOTO(out, rc = 9);
 183
 184         if (ext->oe_state >= OES_STATE_MAX)
 185                 GOTO(out, rc = 10);
 186
 187         if (cfs_atomic_read(&ext->oe_refc) <= 0)
 188                 GOTO(out, rc = 20);
 189
 190         if (cfs_atomic_read(&ext->oe_refc) < cfs_atomic_read(&ext->oe_users))
 191                 GOTO(out, rc = 30);
 192
 193         switch (ext->oe_state) {
 194         case OES_INV:
 195                 if (ext->oe_nr_pages > 0 || !cfs_list_empty(&ext->oe_pages))
 196                         GOTO(out, rc = 35);
 197                 GOTO(out, rc = 0);
 198                 break;
 199         case OES_ACTIVE:
 200                 if (cfs_atomic_read(&ext->oe_users) == 0)
 201                         GOTO(out, rc = 40);
 202                 if (ext->oe_hp)
 203                         GOTO(out, rc = 50);
 204                 if (ext->oe_fsync_wait && !ext->oe_urgent)
 205                         GOTO(out, rc = 55);
 206                 break;
 207         case OES_CACHE:
 208                 if (ext->oe_grants == 0)
 209                         GOTO(out, rc = 60);
 210                 if (ext->oe_fsync_wait && !ext->oe_urgent && !ext->oe_hp)
 211                         GOTO(out, rc = 65);
 212         default:
 213                 if (cfs_atomic_read(&ext->oe_users) > 0)
 214                         GOTO(out, rc = 70);
 215         }
 216
 217         if (ext->oe_max_end < ext->oe_end || ext->oe_end < ext->oe_start)
 218                 GOTO(out, rc = 80);
 219
 220         if (ext->oe_osclock == NULL && ext->oe_grants > 0)
 221                 GOTO(out, rc = 90);
 222
 223         if (ext->oe_osclock) {
 224                 struct cl_lock_descr *descr;
 225                 descr = &ext->oe_osclock->cll_descr;
 226                 if (!(descr->cld_start <= ext->oe_start &&
 227                       descr->cld_end >= ext->oe_max_end))
 228                         GOTO(out, rc = 100);
 229         }
 230
 231         if (ext->oe_nr_pages > ext->oe_mppr)
 232                 GOTO(out, rc = 105);
 233
 234         /* Do not verify page list if extent is in RPC. This is because an
 235          * in-RPC extent is supposed to be exclusively accessible w/o lock. */
 236         if (ext->oe_state > OES_CACHE)
 237                 GOTO(out, rc = 0);
 238
 239         if (!extent_debug)
 240                 GOTO(out, rc = 0);
 241
 242         page_count = 0;
 243         cfs_list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
 244                 pgoff_t index = oap2cl_page(oap)->cp_index;
 245                 ++page_count;
 246                 if (index > ext->oe_end || index < ext->oe_start)
 247                         GOTO(out, rc = 110);
 248         }
 249         if (page_count != ext->oe_nr_pages)
 250                 GOTO(out, rc = 120);
 251
 252 out:
 253         if (rc != 0)
 254                 OSC_EXTENT_DUMP(D_ERROR, ext,
 255                                 "%s:%d sanity check %p failed with rc = %d\n",
 256                                 func, line, ext, rc);
 257         return rc;
 258 }
 259
 260 #define sanity_check_nolock(ext) \
 261         osc_extent_sanity_check0(ext, __func__, __LINE__)
 262
 263 #define sanity_check(ext) ({                                                   \
 264         int __res;                                                             \
 265         osc_object_lock((ext)->oe_obj);                                        \
 266         __res = sanity_check_nolock(ext);                                      \
 267         osc_object_unlock((ext)->oe_obj);                                      \
 268         __res;                                                                 \
 269 })
 270
 271
 272 /**
 273  * sanity check - to make sure there is no overlapped extent in the tree.
 274  */
 275 static int osc_extent_is_overlapped(struct osc_object *obj,
 276                                     struct osc_extent *ext)
 277 {
 278         struct osc_extent *tmp;
 279
 280         LASSERT(osc_object_is_locked(obj));
 281
 282         if (!extent_debug)
 283                 return 0;
 284
 285         for (tmp = first_extent(obj); tmp != NULL; tmp = next_extent(tmp)) {
 286                 if (tmp == ext)
 287                         continue;
 288                 if (tmp->oe_end >= ext->oe_start &&
 289                     tmp->oe_start <= ext->oe_end)
 290                         return 1;
 291         }
 292         return 0;
 293 }
 294
 295 static void osc_extent_state_set(struct osc_extent *ext, int state)
 296 {
 297         LASSERT(osc_object_is_locked(ext->oe_obj));
 298         LASSERT(state >= OES_INV && state < OES_STATE_MAX);
 299
 300         /* Never try to sanity check a state changing extent :-) */
 301         /* LASSERT(sanity_check_nolock(ext) == 0); */
 302
 303         /* TODO: validate the state machine */
 304         ext->oe_state = state;
 305         cfs_waitq_broadcast(&ext->oe_waitq);
 306 }
 307
 308 static struct osc_extent *osc_extent_alloc(struct osc_object *obj)
 309 {
 310         struct osc_extent *ext;
 311
 312         OBD_SLAB_ALLOC_PTR_GFP(ext, osc_extent_kmem, GFP_IOFS);
 313         if (ext == NULL)
 314                 return NULL;
 315
 316         RB_CLEAR_NODE(&ext->oe_node);
 317         ext->oe_obj = obj;
 318         cfs_atomic_set(&ext->oe_refc, 1);
 319         cfs_atomic_set(&ext->oe_users, 0);
 320         CFS_INIT_LIST_HEAD(&ext->oe_link);
 321         ext->oe_state = OES_INV;
 322         CFS_INIT_LIST_HEAD(&ext->oe_pages);
 323         cfs_waitq_init(&ext->oe_waitq);
 324         ext->oe_osclock = NULL;
 325
 326         return ext;
 327 }
 328
 329 static void osc_extent_free(struct osc_extent *ext)
 330 {
 331         OBD_SLAB_FREE_PTR(ext, osc_extent_kmem);
 332 }
 333
 334 static struct osc_extent *osc_extent_get(struct osc_extent *ext)
 335 {
 336         LASSERT(cfs_atomic_read(&ext->oe_refc) >= 0);
 337         cfs_atomic_inc(&ext->oe_refc);
 338         return ext;
 339 }
 340
 341 static void osc_extent_put(const struct lu_env *env, struct osc_extent *ext)
 342 {
 343         LASSERT(cfs_atomic_read(&ext->oe_refc) > 0);
 344         if (cfs_atomic_dec_and_test(&ext->oe_refc)) {
 345                 LASSERT(cfs_list_empty(&ext->oe_link));
 346                 LASSERT(cfs_atomic_read(&ext->oe_users) == 0);
 347                 LASSERT(ext->oe_state == OES_INV);
 348                 LASSERT(!ext->oe_intree);
 349
 350                 if (ext->oe_osclock) {
 351                         cl_lock_put(env, ext->oe_osclock);
 352                         ext->oe_osclock = NULL;
 353                 }
 354                 osc_extent_free(ext);
 355         }
 356 }
 357
 358 /**
 359  * osc_extent_put_trust() is a special version of osc_extent_put() when
 360  * it's known that the caller is not the last user. This is to address the
 361  * problem of lacking of lu_env ;-).
 362  */
 363 static void osc_extent_put_trust(struct osc_extent *ext)
 364 {
 365         LASSERT(cfs_atomic_read(&ext->oe_refc) > 1);
 366         LASSERT(osc_object_is_locked(ext->oe_obj));
 367         cfs_atomic_dec(&ext->oe_refc);
 368 }
 369
 370 /**
 371  * Return the extent which includes pgoff @index, or return the greatest
 372  * previous extent in the tree.
 373  */
 374 static struct osc_extent *osc_extent_search(struct osc_object *obj,
 375                                             pgoff_t index)
 376 {
 377         struct rb_node    *n = obj->oo_root.rb_node;
 378         struct osc_extent *tmp, *p = NULL;
 379
 380         LASSERT(osc_object_is_locked(obj));
 381         while (n != NULL) {
 382                 tmp = rb_extent(n);
 383                 if (index < tmp->oe_start) {
 384                         n = n->rb_left;
 385                 } else if (index > tmp->oe_end) {
 386                         p = rb_extent(n);
 387                         n = n->rb_right;
 388                 } else {
 389                         return tmp;
 390                 }
 391         }
 392         return p;
 393 }
 394
 395 /*
 396  * Return the extent covering @index, otherwise return NULL.
 397  * caller must have held object lock.
 398  */
 399 static struct osc_extent *osc_extent_lookup(struct osc_object *obj,
 400                                             pgoff_t index)
 401 {
 402         struct osc_extent *ext;
 403
 404         ext = osc_extent_search(obj, index);
 405         if (ext != NULL && ext->oe_start <= index && index <= ext->oe_end)
 406                 return osc_extent_get(ext);
 407         return NULL;
 408 }
 409
 410 /* caller must have held object lock. */
 411 static void osc_extent_insert(struct osc_object *obj, struct osc_extent *ext)
 412 {
 413         struct rb_node   **n      = &obj->oo_root.rb_node;
 414         struct rb_node    *parent = NULL;
 415         struct osc_extent *tmp;
 416
 417         LASSERT(ext->oe_intree == 0);
 418         LASSERT(ext->oe_obj == obj);
 419         LASSERT(osc_object_is_locked(obj));
 420         while (*n != NULL) {
 421                 tmp = rb_extent(*n);
 422                 parent = *n;
 423
 424                 if (ext->oe_end < tmp->oe_start)
 425                         n = &(*n)->rb_left;
 426                 else if (ext->oe_start > tmp->oe_end)
 427                         n = &(*n)->rb_right;
 428                 else
 429                         EASSERTF(0, tmp, EXTSTR, EXTPARA(ext));
 430         }
 431         rb_link_node(&ext->oe_node, parent, n);
 432         rb_insert_color(&ext->oe_node, &obj->oo_root);
 433         osc_extent_get(ext);
 434         ext->oe_intree = 1;
 435 }
 436
 437 /* caller must have held object lock. */
 438 static void osc_extent_erase(struct osc_extent *ext)
 439 {
 440         struct osc_object *obj = ext->oe_obj;
 441         LASSERT(osc_object_is_locked(obj));
 442         if (ext->oe_intree) {
 443                 rb_erase(&ext->oe_node, &obj->oo_root);
 444                 ext->oe_intree = 0;
 445                 /* rbtree held a refcount */
 446                 osc_extent_put_trust(ext);
 447         }
 448 }
 449
 450 static struct osc_extent *osc_extent_hold(struct osc_extent *ext)
 451 {
 452         struct osc_object *obj = ext->oe_obj;
 453
 454         LASSERT(osc_object_is_locked(obj));
 455         LASSERT(ext->oe_state == OES_ACTIVE || ext->oe_state == OES_CACHE);
 456         if (ext->oe_state == OES_CACHE) {
 457                 osc_extent_state_set(ext, OES_ACTIVE);
 458                 osc_update_pending(obj, OBD_BRW_WRITE, -ext->oe_nr_pages);
 459         }
 460         cfs_atomic_inc(&ext->oe_users);
 461         cfs_list_del_init(&ext->oe_link);
 462         return osc_extent_get(ext);
 463 }
 464
 465 static void __osc_extent_remove(struct osc_extent *ext)
 466 {
 467         LASSERT(osc_object_is_locked(ext->oe_obj));
 468         LASSERT(cfs_list_empty(&ext->oe_pages));
 469         osc_extent_erase(ext);
 470         cfs_list_del_init(&ext->oe_link);
 471         osc_extent_state_set(ext, OES_INV);
 472         OSC_EXTENT_DUMP(D_CACHE, ext, "destroyed.\n");
 473 }
 474
 475 static void osc_extent_remove(struct osc_extent *ext)
 476 {
 477         struct osc_object *obj = ext->oe_obj;
 478
 479         osc_object_lock(obj);
 480         __osc_extent_remove(ext);
 481         osc_object_unlock(obj);
 482 }
 483
 484 /**
 485  * This function is used to merge extents to get better performance. It checks
 486  * if @cur and @victim are contiguous at chunk level.
 487  */
 488 static int osc_extent_merge(const struct lu_env *env, struct osc_extent *cur,
 489                             struct osc_extent *victim)
 490 {
 491         struct osc_object *obj = cur->oe_obj;
 492         pgoff_t chunk_start;
 493         pgoff_t chunk_end;
 494         int ppc_bits;
 495
 496         LASSERT(cur->oe_state == OES_CACHE);
 497         LASSERT(osc_object_is_locked(obj));
 498         if (victim == NULL)
 499                 return -EINVAL;
 500
 501         if (victim->oe_state != OES_CACHE || victim->oe_fsync_wait)
 502                 return -EBUSY;
 503
 504         if (cur->oe_max_end != victim->oe_max_end)
 505                 return -ERANGE;
 506
 507         LASSERT(cur->oe_osclock == victim->oe_osclock);
 508         ppc_bits = osc_cli(obj)->cl_chunkbits - PAGE_CACHE_SHIFT;
 509         chunk_start = cur->oe_start >> ppc_bits;
 510         chunk_end   = cur->oe_end   >> ppc_bits;
 511         if (chunk_start   != (victim->oe_end >> ppc_bits) + 1 &&
 512             chunk_end + 1 != victim->oe_start >> ppc_bits)
 513                 return -ERANGE;
 514
 515         OSC_EXTENT_DUMP(D_CACHE, victim, "will be merged by %p.\n", cur);
 516
 517         cur->oe_start     = min(cur->oe_start, victim->oe_start);
 518         cur->oe_end       = max(cur->oe_end,   victim->oe_end);
 519         cur->oe_grants   += victim->oe_grants;
 520         cur->oe_nr_pages += victim->oe_nr_pages;
 521         /* only the following bits are needed to merge */
 522         cur->oe_urgent   |= victim->oe_urgent;
 523         cur->oe_memalloc |= victim->oe_memalloc;
 524         cfs_list_splice_init(&victim->oe_pages, &cur->oe_pages);
 525         cfs_list_del_init(&victim->oe_link);
 526         victim->oe_nr_pages = 0;
 527
 528         osc_extent_get(victim);
 529         __osc_extent_remove(victim);
 530         osc_extent_put(env, victim);
 531
 532         OSC_EXTENT_DUMP(D_CACHE, cur, "after merging %p.\n", victim);
 533         return 0;
 534 }
 535
 536 /**
 537  * Drop user count of osc_extent, and unplug IO asynchronously.
 538  */
 539 int osc_extent_release(const struct lu_env *env, struct osc_extent *ext)
 540 {
 541         struct osc_object *obj = ext->oe_obj;
 542         int rc = 0;
 543         ENTRY;
 544
 545         LASSERT(cfs_atomic_read(&ext->oe_users) > 0);
 546         LASSERT(sanity_check(ext) == 0);
 547         LASSERT(ext->oe_grants > 0);
 548
 549         if (cfs_atomic_dec_and_lock(&ext->oe_users, &obj->oo_lock)) {
 550                 LASSERT(ext->oe_state == OES_ACTIVE);
 551                 if (ext->oe_trunc_pending) {
 552                         /* a truncate process is waiting for this extent.
 553                          * This may happen due to a race, check
 554                          * osc_cache_truncate_start(). */
 555                         osc_extent_state_set(ext, OES_TRUNC);
 556                         ext->oe_trunc_pending = 0;
 557                 } else {
 558                         osc_extent_state_set(ext, OES_CACHE);
 559                         osc_update_pending(obj, OBD_BRW_WRITE,
 560                                            ext->oe_nr_pages);
 561
 562                         /* try to merge the previous and next extent. */
 563                         osc_extent_merge(env, ext, prev_extent(ext));
 564                         osc_extent_merge(env, ext, next_extent(ext));
 565
 566                         if (ext->oe_urgent)
 567                                 cfs_list_move_tail(&ext->oe_link,
 568                                                    &obj->oo_urgent_exts);
 569                 }
 570                 osc_object_unlock(obj);
 571
 572                 osc_io_unplug_async(env, osc_cli(obj), obj);
 573         }
 574         osc_extent_put(env, ext);
 575         RETURN(rc);
 576 }
 577
 578 static inline int overlapped(struct osc_extent *ex1, struct osc_extent *ex2)
 579 {
 580         return !(ex1->oe_end < ex2->oe_start || ex2->oe_end < ex1->oe_start);
 581 }
 582
 583 /**
 584  * Find or create an extent which includes @index, core function to manage
 585  * extent tree.
 586  */
 587 struct osc_extent *osc_extent_find(const struct lu_env *env,
 588                                    struct osc_object *obj, pgoff_t index,
 589                                    int *grants)
 590
 591 {
 592         struct client_obd *cli = osc_cli(obj);
 593         struct cl_lock    *lock;
 594         struct osc_extent *cur;
 595         struct osc_extent *ext;
 596         struct osc_extent *conflict = NULL;
 597         struct osc_extent *found = NULL;
 598         pgoff_t    chunk;
 599         pgoff_t    max_end;
 600         int        max_pages; /* max_pages_per_rpc */
 601         int        chunksize;
 602         int        ppc_bits; /* pages per chunk bits */
 603         int        chunk_mask;
 604         int        rc;
 605         ENTRY;
 606
 607         cur = osc_extent_alloc(obj);
 608         if (cur == NULL)
 609                 RETURN(ERR_PTR(-ENOMEM));
 610
 611         lock = cl_lock_at_pgoff(env, osc2cl(obj), index, NULL, 1, 0);
 612         LASSERT(lock != NULL);
 613         LASSERT(lock->cll_descr.cld_mode >= CLM_WRITE);
 614
 615         LASSERT(cli->cl_chunkbits >= PAGE_CACHE_SHIFT);
 616         ppc_bits   = cli->cl_chunkbits - PAGE_CACHE_SHIFT;
 617         chunk_mask = ~((1 << ppc_bits) - 1);
 618         chunksize  = 1 << cli->cl_chunkbits;
 619         chunk      = index >> ppc_bits;
 620
 621         /* align end to rpc edge, rpc size may not be a power 2 integer. */
 622         max_pages = cli->cl_max_pages_per_rpc;
 623         LASSERT((max_pages & ~chunk_mask) == 0);
 624         max_end = index - (index % max_pages) + max_pages - 1;
 625         max_end = min_t(pgoff_t, max_end, lock->cll_descr.cld_end);
 626
 627         /* initialize new extent by parameters so far */
 628         cur->oe_max_end = max_end;
 629         cur->oe_start   = index & chunk_mask;
 630         cur->oe_end     = ((index + ~chunk_mask + 1) & chunk_mask) - 1;
 631         if (cur->oe_start < lock->cll_descr.cld_start)
 632                 cur->oe_start = lock->cll_descr.cld_start;
 633         if (cur->oe_end > max_end)
 634                 cur->oe_end = max_end;
 635         cur->oe_osclock = lock;
 636         cur->oe_grants  = 0;
 637         cur->oe_mppr    = max_pages;
 638
 639         /* grants has been allocated by caller */
 640         LASSERTF(*grants >= chunksize + cli->cl_extent_tax,
 641                  "%u/%u/%u.\n", *grants, chunksize, cli->cl_extent_tax);
 642         LASSERTF((max_end - cur->oe_start) < max_pages, EXTSTR, EXTPARA(cur));
 643
 644 restart:
 645         osc_object_lock(obj);
 646         ext = osc_extent_search(obj, cur->oe_start);
 647         if (ext == NULL)
 648                 ext = first_extent(obj);
 649         while (ext != NULL) {
 650                 loff_t ext_chk_start = ext->oe_start >> ppc_bits;
 651                 loff_t ext_chk_end   = ext->oe_end   >> ppc_bits;
 652
 653                 LASSERT(sanity_check_nolock(ext) == 0);
 654                 if (chunk > ext_chk_end + 1)
 655                         break;
 656
 657                 /* if covering by different locks, no chance to match */
 658                 if (lock != ext->oe_osclock) {
 659                         EASSERTF(!overlapped(ext, cur), ext,
 660                                  EXTSTR, EXTPARA(cur));
 661
 662                         ext = next_extent(ext);
 663                         continue;
 664                 }
 665
 666                 /* discontiguous chunks? */
 667                 if (chunk + 1 < ext_chk_start) {
 668                         ext = next_extent(ext);
 669                         continue;
 670                 }
 671
 672                 /* ok, from now on, ext and cur have these attrs:
 673                  * 1. covered by the same lock
 674                  * 2. contiguous at chunk level or overlapping. */
 675
 676                 if (overlapped(ext, cur)) {
 677                         /* cur is the minimum unit, so overlapping means
 678                          * full contain. */
 679                         EASSERTF((ext->oe_start <= cur->oe_start &&
 680                                   ext->oe_end >= cur->oe_end),
 681                                  ext, EXTSTR, EXTPARA(cur));
 682
 683                         if (ext->oe_state > OES_CACHE || ext->oe_fsync_wait) {
 684                                 /* for simplicity, we wait for this extent to
 685                                  * finish before going forward. */
 686                                 conflict = osc_extent_get(ext);
 687                                 break;
 688                         }
 689
 690                         found = osc_extent_hold(ext);
 691                         break;
 692                 }
 693
 694                 /* non-overlapped extent */
 695                 if (ext->oe_state != OES_CACHE || ext->oe_fsync_wait) {
 696                         /* we can't do anything for a non OES_CACHE extent, or
 697                          * if there is someone waiting for this extent to be
 698                          * flushed, try next one. */
 699                         ext = next_extent(ext);
 700                         continue;
 701                 }
 702
 703                 /* check if they belong to the same rpc slot before trying to
 704                  * merge. the extents are not overlapped and contiguous at
 705                  * chunk level to get here. */
 706                 if (ext->oe_max_end != max_end) {
 707                         /* if they don't belong to the same RPC slot or
 708                          * max_pages_per_rpc has ever changed, do not merge. */
 709                         ext = next_extent(ext);
 710                         continue;
 711                 }
 712
 713                 /* it's required that an extent must be contiguous at chunk
 714                  * level so that we know the whole extent is covered by grant
 715                  * (the pages in the extent are NOT required to be contiguous).
 716                  * Otherwise, it will be too much difficult to know which
 717                  * chunks have grants allocated. */
 718
 719                 /* try to do front merge - extend ext's start */
 720                 if (chunk + 1 == ext_chk_start) {
 721                         /* ext must be chunk size aligned */
 722                         EASSERT((ext->oe_start & ~chunk_mask) == 0, ext);
 723
 724                         /* pull ext's start back to cover cur */
 725                         ext->oe_start   = cur->oe_start;
 726                         ext->oe_grants += chunksize;
 727                         *grants -= chunksize;
 728
 729                         found = osc_extent_hold(ext);
 730                 } else if (chunk == ext_chk_end + 1) {
 731                         /* rear merge */
 732                         ext->oe_end     = cur->oe_end;
 733                         ext->oe_grants += chunksize;
 734                         *grants -= chunksize;
 735
 736                         /* try to merge with the next one because we just fill
 737                          * in a gap */
 738                         if (osc_extent_merge(env, ext, next_extent(ext)) == 0)
 739                                 /* we can save extent tax from next extent */
 740                                 *grants += cli->cl_extent_tax;
 741
 742                         found = osc_extent_hold(ext);
 743                 }
 744                 if (found != NULL)
 745                         break;
 746
 747                 ext = next_extent(ext);
 748         }
 749
 750         osc_extent_tree_dump(D_CACHE, obj);
 751         if (found != NULL) {
 752                 LASSERT(conflict == NULL);
 753                 if (!IS_ERR(found)) {
 754                         LASSERT(found->oe_osclock == cur->oe_osclock);
 755                         OSC_EXTENT_DUMP(D_CACHE, found,
 756                                         "found caching ext for %lu.\n", index);
 757                 }
 758         } else if (conflict == NULL) {
 759                 /* create a new extent */
 760                 EASSERT(osc_extent_is_overlapped(obj, cur) == 0, cur);
 761                 cur->oe_grants = chunksize + cli->cl_extent_tax;
 762                 *grants -= cur->oe_grants;
 763                 LASSERT(*grants >= 0);
 764
 765                 cur->oe_state = OES_CACHE;
 766                 found = osc_extent_hold(cur);
 767                 osc_extent_insert(obj, cur);
 768                 OSC_EXTENT_DUMP(D_CACHE, cur, "add into tree %lu/%lu.\n",
 769                                 index, lock->cll_descr.cld_end);
 770         }
 771         osc_object_unlock(obj);
 772
 773         if (conflict != NULL) {
 774                 LASSERT(found == NULL);
 775
 776                 /* waiting for IO to finish. Please notice that it's impossible
 777                  * to be an OES_TRUNC extent. */
 778                 rc = osc_extent_wait(env, conflict, OES_INV);
 779                 osc_extent_put(env, conflict);
 780                 conflict = NULL;
 781                 if (rc < 0)
 782                         GOTO(out, found = ERR_PTR(rc));
 783
 784                 goto restart;
 785         }
 786         EXIT;
 787
 788 out:
 789         osc_extent_put(env, cur);
 790         LASSERT(*grants >= 0);
 791         return found;
 792 }
 793
 794 /**
 795  * Called when IO is finished to an extent.
 796  */
 797 int osc_extent_finish(const struct lu_env *env, struct osc_extent *ext,
 798                       int sent, int rc)
 799 {
 800         struct client_obd *cli = osc_cli(ext->oe_obj);
 801         struct osc_async_page *oap;
 802         struct osc_async_page *tmp;
 803         int nr_pages = ext->oe_nr_pages;
 804         int lost_grant = 0;
 805         int blocksize = cli->cl_import->imp_obd->obd_osfs.os_bsize ? : 4096;
 806         __u64 last_off = 0;
 807         int last_count = -1;
 808         ENTRY;
 809
 810         OSC_EXTENT_DUMP(D_CACHE, ext, "extent finished.\n");
 811
 812         ext->oe_rc = rc ?: ext->oe_nr_pages;
 813         EASSERT(ergo(rc == 0, ext->oe_state == OES_RPC), ext);
 814         cfs_list_for_each_entry_safe(oap, tmp, &ext->oe_pages,
 815                                      oap_pending_item) {
 816                 cfs_list_del_init(&oap->oap_rpc_item);
 817                 cfs_list_del_init(&oap->oap_pending_item);
 818                 if (last_off <= oap->oap_obj_off) {
 819                         last_off = oap->oap_obj_off;
 820                         last_count = oap->oap_count;
 821                 }
 822
 823                 --ext->oe_nr_pages;
 824                 osc_ap_completion(env, cli, oap, sent, rc);
 825         }
 826         EASSERT(ext->oe_nr_pages == 0, ext);
 827
 828         if (!sent) {
 829                 lost_grant = ext->oe_grants;
 830         } else if (blocksize < PAGE_CACHE_SIZE &&
 831                    last_count != PAGE_CACHE_SIZE) {
 832                 /* For short writes we shouldn't count parts of pages that
 833                  * span a whole chunk on the OST side, or our accounting goes
 834                  * wrong.  Should match the code in filter_grant_check. */
 835                 int offset = oap->oap_page_off & ~CFS_PAGE_MASK;
 836                 int count = oap->oap_count + (offset & (blocksize - 1));
 837                 int end = (offset + oap->oap_count) & (blocksize - 1);
 838                 if (end)
 839                         count += blocksize - end;
 840
 841                 lost_grant = PAGE_CACHE_SIZE - count;
 842         }
 843         if (ext->oe_grants > 0)
 844                 osc_free_grant(cli, nr_pages, lost_grant);
 845
 846         osc_extent_remove(ext);
 847         /* put the refcount for RPC */
 848         osc_extent_put(env, ext);
 849         RETURN(0);
 850 }
 851
 852 static int extent_wait_cb(struct osc_extent *ext, int state)
 853 {
 854         int ret;
 855
 856         osc_object_lock(ext->oe_obj);
 857         ret = ext->oe_state == state;
 858         osc_object_unlock(ext->oe_obj);
 859
 860         return ret;
 861 }
 862
 863 /**
 864  * Wait for the extent's state to become @state.
 865  */
 866 static int osc_extent_wait(const struct lu_env *env, struct osc_extent *ext,
 867                            int state)
 868 {
 869         struct osc_object *obj = ext->oe_obj;
 870         struct l_wait_info lwi = LWI_TIMEOUT_INTR(cfs_time_seconds(600), NULL,
 871                                                   LWI_ON_SIGNAL_NOOP, NULL);
 872         int rc = 0;
 873         ENTRY;
 874
 875         osc_object_lock(obj);
 876         LASSERT(sanity_check_nolock(ext) == 0);
 877         /* `Kick' this extent only if the caller is waiting for it to be
 878          * written out. */
 879         if (state == OES_INV && !ext->oe_urgent && !ext->oe_hp) {
 880                 if (ext->oe_state == OES_ACTIVE) {
 881                         ext->oe_urgent = 1;
 882                 } else if (ext->oe_state == OES_CACHE) {
 883                         ext->oe_urgent = 1;
 884                         osc_extent_hold(ext);
 885                         rc = 1;
 886                 }
 887         }
 888         osc_object_unlock(obj);
 889         if (rc == 1)
 890                 osc_extent_release(env, ext);
 891
 892         /* wait for the extent until its state becomes @state */
 893         rc = l_wait_event(ext->oe_waitq, extent_wait_cb(ext, state), &lwi);
 894         if (rc == -ETIMEDOUT) {
 895                 OSC_EXTENT_DUMP(D_ERROR, ext,
 896                         "%s: wait ext to %d timedout, recovery in progress?\n",
 897                         osc_export(obj)->exp_obd->obd_name, state);
 898
 899                 lwi = LWI_INTR(LWI_ON_SIGNAL_NOOP, NULL);
 900                 rc = l_wait_event(ext->oe_waitq, extent_wait_cb(ext, state),
 901                                   &lwi);
 902         }
 903         if (rc == 0 && ext->oe_rc < 0)
 904                 rc = ext->oe_rc;
 905         RETURN(rc);
 906 }
 907
 908 /**
 909  * Discard pages with index greater than @size. If @ext is overlapped with
 910  * @size, then partial truncate happens.
 911  */
 912 static int osc_extent_truncate(struct osc_extent *ext, pgoff_t trunc_index,
 913                                 bool partial)
 914 {
 915         struct cl_env_nest     nest;
 916         struct lu_env         *env;
 917         struct cl_io          *io;
 918         struct osc_object     *obj = ext->oe_obj;
 919         struct client_obd     *cli = osc_cli(obj);
 920         struct osc_async_page *oap;
 921         struct osc_async_page *tmp;
 922         int                    pages_in_chunk = 0;
 923         int                    ppc_bits    = cli->cl_chunkbits -
 924                                              PAGE_CACHE_SHIFT;
 925         __u64                  trunc_chunk = trunc_index >> ppc_bits;
 926         int                    grants   = 0;
 927         int                    nr_pages = 0;
 928         int                    rc       = 0;
 929         ENTRY;
 930
 931         LASSERT(sanity_check(ext) == 0);
 932         LASSERT(ext->oe_state == OES_TRUNC);
 933         LASSERT(!ext->oe_urgent);
 934
 935         /* Request new lu_env.
 936          * We can't use that env from osc_cache_truncate_start() because
 937          * it's from lov_io_sub and not fully initialized. */
 938         env = cl_env_nested_get(&nest);
 939         io  = &osc_env_info(env)->oti_io;
 940         io->ci_obj = cl_object_top(osc2cl(obj));
 941         rc = cl_io_init(env, io, CIT_MISC, io->ci_obj);
 942         if (rc < 0)
 943                 GOTO(out, rc);
 944
 945         /* discard all pages with index greater then trunc_index */
 946         cfs_list_for_each_entry_safe(oap, tmp, &ext->oe_pages,
 947                                      oap_pending_item) {
 948                 struct cl_page  *sub  = oap2cl_page(oap);
 949                 struct cl_page  *page = cl_page_top(sub);
 950
 951                 LASSERT(cfs_list_empty(&oap->oap_rpc_item));
 952
 953                 /* only discard the pages with their index greater than
 954                  * trunc_index, and ... */
 955                 if (sub->cp_index < trunc_index ||
 956                     (sub->cp_index == trunc_index && partial)) {
 957                         /* accounting how many pages remaining in the chunk
 958                          * so that we can calculate grants correctly. */
 959                         if (sub->cp_index >> ppc_bits == trunc_chunk)
 960                                 ++pages_in_chunk;
 961                         continue;
 962                 }
 963
 964                 cfs_list_del_init(&oap->oap_pending_item);
 965
 966                 cl_page_get(page);
 967                 lu_ref_add(&page->cp_reference, "truncate", cfs_current());
 968
 969                 if (cl_page_own(env, io, page) == 0) {
 970                         cl_page_unmap(env, io, page);
 971                         cl_page_discard(env, io, page);
 972                         cl_page_disown(env, io, page);
 973                 } else {
 974                         LASSERT(page->cp_state == CPS_FREEING);
 975                         LASSERT(0);
 976                 }
 977
 978                 lu_ref_del(&page->cp_reference, "truncate", cfs_current());
 979                 cl_page_put(env, page);
 980
 981                 --ext->oe_nr_pages;
 982                 ++nr_pages;
 983         }
 984         EASSERTF(ergo(ext->oe_start >= trunc_index + !!partial,
 985                       ext->oe_nr_pages == 0),
 986                 ext, "trunc_index %lu, partial %d\n", trunc_index, partial);
 987
 988         osc_object_lock(obj);
 989         if (ext->oe_nr_pages == 0) {
 990                 LASSERT(pages_in_chunk == 0);
 991                 grants = ext->oe_grants;
 992                 ext->oe_grants = 0;
 993         } else { /* calculate how many grants we can free */
 994                 int     chunks = (ext->oe_end >> ppc_bits) - trunc_chunk;
 995                 pgoff_t last_index;
 996
 997
 998                 /* if there is no pages in this chunk, we can also free grants
 999                  * for the last chunk */
1000                 if (pages_in_chunk == 0) {
1001                         /* if this is the 1st chunk and no pages in this chunk,
1002                          * ext->oe_nr_pages must be zero, so we should be in
1003                          * the other if-clause. */
1004                         LASSERT(trunc_chunk > 0);
1005                         --trunc_chunk;
1006                         ++chunks;
1007                 }
1008
1009                 /* this is what we can free from this extent */
1010                 grants          = chunks << cli->cl_chunkbits;
1011                 ext->oe_grants -= grants;
1012                 last_index      = ((trunc_chunk + 1) << ppc_bits) - 1;
1013                 ext->oe_end     = min(last_index, ext->oe_max_end);
1014                 LASSERT(ext->oe_end >= ext->oe_start);
1015                 LASSERT(ext->oe_grants > 0);
1016         }
1017         osc_object_unlock(obj);
1018
1019         if (grants > 0 || nr_pages > 0)
1020                 osc_free_grant(cli, nr_pages, grants);
1021
1022 out:
1023         cl_io_fini(env, io);
1024         cl_env_nested_put(&nest, env);
1025         RETURN(rc);
1026 }
1027
1028 /**
1029  * This function is used to make the extent prepared for transfer.
1030  * A race with flusing page - ll_writepage() has to be handled cautiously.
1031  */
1032 static int osc_extent_make_ready(const struct lu_env *env,
1033                                  struct osc_extent *ext)
1034 {
1035         struct osc_async_page *oap;
1036         struct osc_async_page *last = NULL;
1037         struct osc_object *obj = ext->oe_obj;
1038         int page_count = 0;
1039         int rc;
1040         ENTRY;
1041
1042         /* we're going to grab page lock, so object lock must not be taken. */
1043         LASSERT(sanity_check(ext) == 0);
1044         /* in locking state, any process should not touch this extent. */
1045         EASSERT(ext->oe_state == OES_LOCKING, ext);
1046         EASSERT(ext->oe_owner != NULL, ext);
1047
1048         OSC_EXTENT_DUMP(D_CACHE, ext, "make ready\n");
1049
1050         cfs_list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
1051                 ++page_count;
1052                 if (last == NULL || last->oap_obj_off < oap->oap_obj_off)
1053                         last = oap;
1054
1055                 /* checking ASYNC_READY is race safe */
1056                 if ((oap->oap_async_flags & ASYNC_READY) != 0)
1057                         continue;
1058
1059                 rc = osc_make_ready(env, oap, OBD_BRW_WRITE);
1060                 switch (rc) {
1061                 case 0:
1062                         spin_lock(&oap->oap_lock);
1063                         oap->oap_async_flags |= ASYNC_READY;
1064                         spin_unlock(&oap->oap_lock);
1065                         break;
1066                 case -EALREADY:
1067                         LASSERT((oap->oap_async_flags & ASYNC_READY) != 0);
1068                         break;
1069                 default:
1070                         LASSERTF(0, "unknown return code: %d\n", rc);
1071                 }
1072         }
1073
1074         LASSERT(page_count == ext->oe_nr_pages);
1075         LASSERT(last != NULL);
1076         /* the last page is the only one we need to refresh its count by
1077          * the size of file. */
1078         if (!(last->oap_async_flags & ASYNC_COUNT_STABLE)) {
1079                 last->oap_count = osc_refresh_count(env, last, OBD_BRW_WRITE);
1080                 LASSERT(last->oap_count > 0);
1081                 LASSERT(last->oap_page_off + last->oap_count <= PAGE_CACHE_SIZE);
1082                 last->oap_async_flags |= ASYNC_COUNT_STABLE;
1083         }
1084
1085         /* for the rest of pages, we don't need to call osf_refresh_count()
1086          * because it's known they are not the last page */
1087         cfs_list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
1088                 if (!(oap->oap_async_flags & ASYNC_COUNT_STABLE)) {
1089                         oap->oap_count = PAGE_CACHE_SIZE - oap->oap_page_off;
1090                         oap->oap_async_flags |= ASYNC_COUNT_STABLE;
1091                 }
1092         }
1093
1094         osc_object_lock(obj);
1095         osc_extent_state_set(ext, OES_RPC);
1096         osc_object_unlock(obj);
1097         /* get a refcount for RPC. */
1098         osc_extent_get(ext);
1099
1100         RETURN(0);
1101 }
1102
1103 /**
1104  * Quick and simple version of osc_extent_find(). This function is frequently
1105  * called to expand the extent for the same IO. To expand the extent, the
1106  * page index must be in the same or next chunk of ext->oe_end.
1107  */
1108 static int osc_extent_expand(struct osc_extent *ext, pgoff_t index, int *grants)
1109 {
1110         struct osc_object *obj = ext->oe_obj;
1111         struct client_obd *cli = osc_cli(obj);
1112         struct osc_extent *next;
1113         int ppc_bits = cli->cl_chunkbits - PAGE_CACHE_SHIFT;
1114         pgoff_t chunk = index >> ppc_bits;
1115         pgoff_t end_chunk;
1116         pgoff_t end_index;
1117         int chunksize = 1 << cli->cl_chunkbits;
1118         int rc = 0;
1119         ENTRY;
1120
1121         LASSERT(ext->oe_max_end >= index && ext->oe_start <= index);
1122         osc_object_lock(obj);
1123         LASSERT(sanity_check_nolock(ext) == 0);
1124         end_chunk = ext->oe_end >> ppc_bits;
1125         if (chunk > end_chunk + 1)
1126                 GOTO(out, rc = -ERANGE);
1127
1128         if (end_chunk >= chunk)
1129                 GOTO(out, rc = 0);
1130
1131         LASSERT(end_chunk + 1 == chunk);
1132         /* try to expand this extent to cover @index */
1133         end_index = min(ext->oe_max_end, ((chunk + 1) << ppc_bits) - 1);
1134
1135         next = next_extent(ext);
1136         if (next != NULL && next->oe_start <= end_index)
1137                 /* complex mode - overlapped with the next extent,
1138                  * this case will be handled by osc_extent_find() */
1139                 GOTO(out, rc = -EAGAIN);
1140
1141         ext->oe_end = end_index;
1142         ext->oe_grants += chunksize;
1143         *grants -= chunksize;
1144         LASSERT(*grants >= 0);
1145         EASSERTF(osc_extent_is_overlapped(obj, ext) == 0, ext,
1146                  "overlapped after expanding for %lu.\n", index);
1147         EXIT;
1148
1149 out:
1150         osc_object_unlock(obj);
1151         RETURN(rc);
1152 }
1153
1154 static void osc_extent_tree_dump0(int level, struct osc_object *obj,
1155                                   const char *func, int line)
1156 {
1157         struct osc_extent *ext;
1158         int cnt;
1159
1160         CDEBUG(level, "Dump object %p extents at %s:%d, mppr: %u.\n",
1161                obj, func, line, osc_cli(obj)->cl_max_pages_per_rpc);
1162
1163         /* osc_object_lock(obj); */
1164         cnt = 1;
1165         for (ext = first_extent(obj); ext != NULL; ext = next_extent(ext))
1166                 OSC_EXTENT_DUMP(level, ext, "in tree %d.\n", cnt++);
1167
1168         cnt = 1;
1169         cfs_list_for_each_entry(ext, &obj->oo_hp_exts, oe_link)
1170                 OSC_EXTENT_DUMP(level, ext, "hp %d.\n", cnt++);
1171
1172         cnt = 1;
1173         cfs_list_for_each_entry(ext, &obj->oo_urgent_exts, oe_link)
1174                 OSC_EXTENT_DUMP(level, ext, "urgent %d.\n", cnt++);
1175
1176         cnt = 1;
1177         cfs_list_for_each_entry(ext, &obj->oo_reading_exts, oe_link)
1178                 OSC_EXTENT_DUMP(level, ext, "reading %d.\n", cnt++);
1179         /* osc_object_unlock(obj); */
1180 }
1181
1182 /* ------------------ osc extent end ------------------ */
1183
1184 static inline int osc_is_ready(struct osc_object *osc)
1185 {
1186         return !cfs_list_empty(&osc->oo_ready_item) ||
1187                !cfs_list_empty(&osc->oo_hp_ready_item);
1188 }
1189
1190 #define OSC_IO_DEBUG(OSC, STR, args...)                                        \
1191         CDEBUG(D_CACHE, "obj %p ready %d|%c|%c wr %d|%c|%c rd %d|%c " STR,     \
1192                (OSC), osc_is_ready(OSC),                                       \
1193                list_empty_marker(&(OSC)->oo_hp_ready_item),                    \
1194                list_empty_marker(&(OSC)->oo_ready_item),                       \
1195                cfs_atomic_read(&(OSC)->oo_nr_writes),                          \
1196                list_empty_marker(&(OSC)->oo_hp_exts),                          \
1197                list_empty_marker(&(OSC)->oo_urgent_exts),                      \
1198                cfs_atomic_read(&(OSC)->oo_nr_reads),                           \
1199                list_empty_marker(&(OSC)->oo_reading_exts),                     \
1200                ##args)
1201
1202 static int osc_make_ready(const struct lu_env *env, struct osc_async_page *oap,
1203                           int cmd)
1204 {
1205         struct osc_page *opg  = oap2osc_page(oap);
1206         struct cl_page  *page = cl_page_top(oap2cl_page(oap));
1207         int result;
1208
1209         LASSERT(cmd == OBD_BRW_WRITE); /* no cached reads */
1210
1211         ENTRY;
1212         result = cl_page_make_ready(env, page, CRT_WRITE);
1213         if (result == 0)
1214                 opg->ops_submit_time = cfs_time_current();
1215         RETURN(result);
1216 }
1217
1218 static int osc_refresh_count(const struct lu_env *env,
1219                              struct osc_async_page *oap, int cmd)
1220 {
1221         struct osc_page  *opg = oap2osc_page(oap);
1222         struct cl_page   *page = oap2cl_page(oap);
1223         struct cl_object *obj;
1224         struct cl_attr   *attr = &osc_env_info(env)->oti_attr;
1225
1226         int result;
1227         loff_t kms;
1228
1229         /* readpage queues with _COUNT_STABLE, shouldn't get here. */
1230         LASSERT(!(cmd & OBD_BRW_READ));
1231         LASSERT(opg != NULL);
1232         obj = opg->ops_cl.cpl_obj;
1233
1234         cl_object_attr_lock(obj);
1235         result = cl_object_attr_get(env, obj, attr);
1236         cl_object_attr_unlock(obj);
1237         if (result < 0)
1238                 return result;
1239         kms = attr->cat_kms;
1240         if (cl_offset(obj, page->cp_index) >= kms)
1241                 /* catch race with truncate */
1242                 return 0;
1243         else if (cl_offset(obj, page->cp_index + 1) > kms)
1244                 /* catch sub-page write at end of file */
1245                 return kms % PAGE_CACHE_SIZE;
1246         else
1247                 return PAGE_CACHE_SIZE;
1248 }
1249
1250 static int osc_completion(const struct lu_env *env, struct osc_async_page *oap,
1251                           int cmd, int rc)
1252 {
1253         struct osc_page   *opg  = oap2osc_page(oap);
1254         struct cl_page    *page = cl_page_top(oap2cl_page(oap));
1255         struct osc_object *obj  = cl2osc(opg->ops_cl.cpl_obj);
1256         enum cl_req_type   crt;
1257         int srvlock;
1258
1259         ENTRY;
1260
1261         cmd &= ~OBD_BRW_NOQUOTA;
1262         LASSERT(equi(page->cp_state == CPS_PAGEIN,  cmd == OBD_BRW_READ));
1263         LASSERT(equi(page->cp_state == CPS_PAGEOUT, cmd == OBD_BRW_WRITE));
1264         LASSERT(opg->ops_transfer_pinned);
1265
1266         /*
1267          * page->cp_req can be NULL if io submission failed before
1268          * cl_req was allocated.
1269          */
1270         if (page->cp_req != NULL)
1271                 cl_req_page_done(env, page);
1272         LASSERT(page->cp_req == NULL);
1273
1274         crt = cmd == OBD_BRW_READ ? CRT_READ : CRT_WRITE;
1275         /* Clear opg->ops_transfer_pinned before VM lock is released. */
1276         opg->ops_transfer_pinned = 0;
1277
1278         spin_lock(&obj->oo_seatbelt);
1279         LASSERT(opg->ops_submitter != NULL);
1280         LASSERT(!cfs_list_empty(&opg->ops_inflight));
1281         cfs_list_del_init(&opg->ops_inflight);
1282         opg->ops_submitter = NULL;
1283         spin_unlock(&obj->oo_seatbelt);
1284
1285         opg->ops_submit_time = 0;
1286         srvlock = oap->oap_brw_flags & OBD_BRW_SRVLOCK;
1287
1288         /* statistic */
1289         if (rc == 0 && srvlock) {
1290                 struct lu_device *ld    = opg->ops_cl.cpl_obj->co_lu.lo_dev;
1291                 struct osc_stats *stats = &lu2osc_dev(ld)->od_stats;
1292                 int bytes = oap->oap_count;
1293
1294                 if (crt == CRT_READ)
1295                         stats->os_lockless_reads += bytes;
1296                 else
1297                         stats->os_lockless_writes += bytes;
1298         }
1299
1300         /*
1301          * This has to be the last operation with the page, as locks are
1302          * released in cl_page_completion() and nothing except for the
1303          * reference counter protects page from concurrent reclaim.
1304          */
1305         lu_ref_del(&page->cp_reference, "transfer", page);
1306
1307         cl_page_completion(env, page, crt, rc);
1308
1309         RETURN(0);
1310 }
1311
1312 #define OSC_DUMP_GRANT(cli, fmt, args...) do {                                \
1313         struct client_obd *__tmp = (cli);                                     \
1314         CDEBUG(D_CACHE, "%s: { dirty: %ld/%ld dirty_pages: %d/%d "            \
1315                "dropped: %ld avail: %ld, reserved: %ld, flight: %d } " fmt,   \
1316                __tmp->cl_import->imp_obd->obd_name,                           \
1317                __tmp->cl_dirty, __tmp->cl_dirty_max,                          \
1318                cfs_atomic_read(&obd_dirty_pages), obd_max_dirty_pages,        \
1319                __tmp->cl_lost_grant, __tmp->cl_avail_grant,                   \
1320                __tmp->cl_reserved_grant, __tmp->cl_w_in_flight, ##args);      \
1321 } while (0)
1322
1323 /* caller must hold loi_list_lock */
1324 static void osc_consume_write_grant(struct client_obd *cli,
1325                                     struct brw_page *pga)
1326 {
1327         LASSERT(spin_is_locked(&cli->cl_loi_list_lock.lock));
1328         LASSERT(!(pga->flag & OBD_BRW_FROM_GRANT));
1329         cfs_atomic_inc(&obd_dirty_pages);
1330         cli->cl_dirty += PAGE_CACHE_SIZE;
1331         pga->flag |= OBD_BRW_FROM_GRANT;
1332         CDEBUG(D_CACHE, "using %lu grant credits for brw %p page %p\n",
1333                PAGE_CACHE_SIZE, pga, pga->pg);
1334         osc_update_next_shrink(cli);
1335 }
1336
1337 /* the companion to osc_consume_write_grant, called when a brw has completed.
1338  * must be called with the loi lock held. */
1339 static void osc_release_write_grant(struct client_obd *cli,
1340                                     struct brw_page *pga)
1341 {
1342         ENTRY;
1343
1344         LASSERT(spin_is_locked(&cli->cl_loi_list_lock.lock));
1345         if (!(pga->flag & OBD_BRW_FROM_GRANT)) {
1346                 EXIT;
1347                 return;
1348         }
1349
1350         pga->flag &= ~OBD_BRW_FROM_GRANT;
1351         cfs_atomic_dec(&obd_dirty_pages);
1352         cli->cl_dirty -= PAGE_CACHE_SIZE;
1353         if (pga->flag & OBD_BRW_NOCACHE) {
1354                 pga->flag &= ~OBD_BRW_NOCACHE;
1355                 cfs_atomic_dec(&obd_dirty_transit_pages);
1356                 cli->cl_dirty_transit -= PAGE_CACHE_SIZE;
1357         }
1358         EXIT;
1359 }
1360
1361 /**
1362  * To avoid sleeping with object lock held, it's good for us allocate enough
1363  * grants before entering into critical section.
1364  *
1365  * client_obd_list_lock held by caller
1366  */
1367 static int osc_reserve_grant(struct client_obd *cli, unsigned int bytes)
1368 {
1369         int rc = -EDQUOT;
1370
1371         if (cli->cl_avail_grant >= bytes) {
1372                 cli->cl_avail_grant    -= bytes;
1373                 cli->cl_reserved_grant += bytes;
1374                 rc = 0;
1375         }
1376         return rc;
1377 }
1378
1379 static void __osc_unreserve_grant(struct client_obd *cli,
1380                                   unsigned int reserved, unsigned int unused)
1381 {
1382         /* it's quite normal for us to get more grant than reserved.
1383          * Thinking about a case that two extents merged by adding a new
1384          * chunk, we can save one extent tax. If extent tax is greater than
1385          * one chunk, we can save more grant by adding a new chunk */
1386         cli->cl_reserved_grant -= reserved;
1387         if (unused > reserved) {
1388                 cli->cl_avail_grant += reserved;
1389                 cli->cl_lost_grant  += unused - reserved;
1390         } else {
1391                 cli->cl_avail_grant += unused;
1392         }
1393 }
1394
1395 void osc_unreserve_grant(struct client_obd *cli,
1396                          unsigned int reserved, unsigned int unused)
1397 {
1398         client_obd_list_lock(&cli->cl_loi_list_lock);
1399         __osc_unreserve_grant(cli, reserved, unused);
1400         if (unused > 0)
1401                 osc_wake_cache_waiters(cli);
1402         client_obd_list_unlock(&cli->cl_loi_list_lock);
1403 }
1404
1405 /**
1406  * Free grant after IO is finished or canceled.
1407  *
1408  * @lost_grant is used to remember how many grants we have allocated but not
1409  * used, we should return these grants to OST. There're two cases where grants
1410  * can be lost:
1411  * 1. truncate;
1412  * 2. blocksize at OST is less than PAGE_CACHE_SIZE and a partial page was
1413  *    written. In this case OST may use less chunks to serve this partial
1414  *    write. OSTs don't actually know the page size on the client side. so
1415  *    clients have to calculate lost grant by the blocksize on the OST.
1416  *    See filter_grant_check() for details.
1417  */
1418 static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
1419                            unsigned int lost_grant)
1420 {
1421         int grant = (1 << cli->cl_chunkbits) + cli->cl_extent_tax;
1422
1423         client_obd_list_lock(&cli->cl_loi_list_lock);
1424         cfs_atomic_sub(nr_pages, &obd_dirty_pages);
1425         cli->cl_dirty -= nr_pages << PAGE_CACHE_SHIFT;
1426         cli->cl_lost_grant += lost_grant;
1427         if (cli->cl_avail_grant < grant && cli->cl_lost_grant >= grant) {
1428                 /* borrow some grant from truncate to avoid the case that
1429                  * truncate uses up all avail grant */
1430                 cli->cl_lost_grant -= grant;
1431                 cli->cl_avail_grant += grant;
1432         }
1433         osc_wake_cache_waiters(cli);
1434         client_obd_list_unlock(&cli->cl_loi_list_lock);
1435         CDEBUG(D_CACHE, "lost %u grant: %lu avail: %lu dirty: %lu\n",
1436                lost_grant, cli->cl_lost_grant,
1437                cli->cl_avail_grant, cli->cl_dirty);
1438 }
1439
1440 /**
1441  * The companion to osc_enter_cache(), called when @oap is no longer part of
1442  * the dirty accounting due to error.
1443  */
1444 static void osc_exit_cache(struct client_obd *cli, struct osc_async_page *oap)
1445 {
1446         client_obd_list_lock(&cli->cl_loi_list_lock);
1447         osc_release_write_grant(cli, &oap->oap_brw_page);
1448         client_obd_list_unlock(&cli->cl_loi_list_lock);
1449 }
1450
1451 /**
1452  * Non-blocking version of osc_enter_cache() that consumes grant only when it
1453  * is available.
1454  */
1455 static int osc_enter_cache_try(struct client_obd *cli,
1456                                struct osc_async_page *oap,
1457                                int bytes, int transient)
1458 {
1459         int rc;
1460
1461         OSC_DUMP_GRANT(cli, "need:%d.\n", bytes);
1462
1463         rc = osc_reserve_grant(cli, bytes);
1464         if (rc < 0)
1465                 return 0;
1466
1467         if (cli->cl_dirty + PAGE_CACHE_SIZE <= cli->cl_dirty_max &&
1468             cfs_atomic_read(&obd_dirty_pages) + 1 <= obd_max_dirty_pages) {
1469                 osc_consume_write_grant(cli, &oap->oap_brw_page);
1470                 if (transient) {
1471                         cli->cl_dirty_transit += PAGE_CACHE_SIZE;
1472                         cfs_atomic_inc(&obd_dirty_transit_pages);
1473                         oap->oap_brw_flags |= OBD_BRW_NOCACHE;
1474                 }
1475                 rc = 1;
1476         } else {
1477                 __osc_unreserve_grant(cli, bytes, bytes);
1478                 rc = 0;
1479         }
1480         return rc;
1481 }
1482
1483 static int ocw_granted(struct client_obd *cli, struct osc_cache_waiter *ocw)
1484 {
1485         int rc;
1486         client_obd_list_lock(&cli->cl_loi_list_lock);
1487         rc = cfs_list_empty(&ocw->ocw_entry);
1488         client_obd_list_unlock(&cli->cl_loi_list_lock);
1489         return rc;
1490 }
1491
1492 /**
1493  * The main entry to reserve dirty page accounting. Usually the grant reserved
1494  * in this function will be freed in bulk in osc_free_grant() unless it fails
1495  * to add osc cache, in that case, it will be freed in osc_exit_cache().
1496  *
1497  * The process will be put into sleep if it's already run out of grant.
1498  */
1499 static int osc_enter_cache(const struct lu_env *env, struct client_obd *cli,
1500                            struct osc_async_page *oap, int bytes)
1501 {
1502         struct osc_object *osc = oap->oap_obj;
1503         struct lov_oinfo  *loi = osc->oo_oinfo;
1504         struct osc_cache_waiter ocw;
1505         struct l_wait_info lwi = LWI_INTR(LWI_ON_SIGNAL_NOOP, NULL);
1506         int rc = -EDQUOT;
1507         ENTRY;
1508
1509         OSC_DUMP_GRANT(cli, "need:%d.\n", bytes);
1510
1511         client_obd_list_lock(&cli->cl_loi_list_lock);
1512
1513         /* force the caller to try sync io.  this can jump the list
1514          * of queued writes and create a discontiguous rpc stream */
1515         if (OBD_FAIL_CHECK(OBD_FAIL_OSC_NO_GRANT) ||
1516             cli->cl_dirty_max < PAGE_CACHE_SIZE     ||
1517             cli->cl_ar.ar_force_sync || loi->loi_ar.ar_force_sync)
1518                 GOTO(out, rc = -EDQUOT);
1519
1520         /* Hopefully normal case - cache space and write credits available */
1521         if (osc_enter_cache_try(cli, oap, bytes, 0))
1522                 GOTO(out, rc = 0);
1523
1524         /* We can get here for two reasons: too many dirty pages in cache, or
1525          * run out of grants. In both cases we should write dirty pages out.
1526          * Adding a cache waiter will trigger urgent write-out no matter what
1527          * RPC size will be.
1528          * The exiting condition is no avail grants and no dirty pages caching,
1529          * that really means there is no space on the OST. */
1530         cfs_waitq_init(&ocw.ocw_waitq);
1531         ocw.ocw_oap   = oap;
1532         ocw.ocw_grant = bytes;
1533         while (cli->cl_dirty > 0 || cli->cl_w_in_flight > 0) {
1534                 cfs_list_add_tail(&ocw.ocw_entry, &cli->cl_cache_waiters);
1535                 ocw.ocw_rc = 0;
1536                 client_obd_list_unlock(&cli->cl_loi_list_lock);
1537
1538                 osc_io_unplug_async(env, cli, NULL);
1539
1540                 CDEBUG(D_CACHE, "%s: sleeping for cache space @ %p for %p\n",
1541                        cli->cl_import->imp_obd->obd_name, &ocw, oap);
1542
1543                 rc = l_wait_event(ocw.ocw_waitq, ocw_granted(cli, &ocw), &lwi);
1544
1545                 client_obd_list_lock(&cli->cl_loi_list_lock);
1546
1547                 /* l_wait_event is interrupted by signal */
1548                 if (rc < 0) {
1549                         cfs_list_del_init(&ocw.ocw_entry);
1550                         GOTO(out, rc);
1551                 }
1552
1553                 LASSERT(cfs_list_empty(&ocw.ocw_entry));
1554                 rc = ocw.ocw_rc;
1555
1556                 if (rc != -EDQUOT)
1557                         GOTO(out, rc);
1558                 if (osc_enter_cache_try(cli, oap, bytes, 0))
1559                         GOTO(out, rc = 0);
1560         }
1561         EXIT;
1562 out:
1563         client_obd_list_unlock(&cli->cl_loi_list_lock);
1564         OSC_DUMP_GRANT(cli, "returned %d.\n", rc);
1565         RETURN(rc);
1566 }
1567
1568 /* caller must hold loi_list_lock */
1569 void osc_wake_cache_waiters(struct client_obd *cli)
1570 {
1571         cfs_list_t *l, *tmp;
1572         struct osc_cache_waiter *ocw;
1573
1574         ENTRY;
1575         cfs_list_for_each_safe(l, tmp, &cli->cl_cache_waiters) {
1576                 ocw = cfs_list_entry(l, struct osc_cache_waiter, ocw_entry);
1577                 cfs_list_del_init(&ocw->ocw_entry);
1578
1579                 ocw->ocw_rc = -EDQUOT;
1580                 /* we can't dirty more */
1581                 if ((cli->cl_dirty + PAGE_CACHE_SIZE > cli->cl_dirty_max) ||
1582                     (cfs_atomic_read(&obd_dirty_pages) + 1 >
1583                      obd_max_dirty_pages)) {
1584                         CDEBUG(D_CACHE, "no dirty room: dirty: %ld "
1585                                "osc max %ld, sys max %d\n", cli->cl_dirty,
1586                                cli->cl_dirty_max, obd_max_dirty_pages);
1587                         goto wakeup;
1588                 }
1589
1590                 ocw->ocw_rc = 0;
1591                 if (!osc_enter_cache_try(cli, ocw->ocw_oap, ocw->ocw_grant, 0))
1592                         ocw->ocw_rc = -EDQUOT;
1593
1594 wakeup:
1595                 CDEBUG(D_CACHE, "wake up %p for oap %p, avail grant %ld, %d\n",
1596                        ocw, ocw->ocw_oap, cli->cl_avail_grant, ocw->ocw_rc);
1597
1598                 cfs_waitq_signal(&ocw->ocw_waitq);
1599         }
1600
1601         EXIT;
1602 }
1603
1604 static int osc_max_rpc_in_flight(struct client_obd *cli, struct osc_object *osc)
1605 {
1606         int hprpc = !!cfs_list_empty(&osc->oo_hp_exts);
1607         return rpcs_in_flight(cli) >= cli->cl_max_rpcs_in_flight + hprpc;
1608 }
1609
1610 /* This maintains the lists of pending pages to read/write for a given object
1611  * (lop).  This is used by osc_check_rpcs->osc_next_obj() and osc_list_maint()
1612  * to quickly find objects that are ready to send an RPC. */
1613 static int osc_makes_rpc(struct client_obd *cli, struct osc_object *osc,
1614                          int cmd)
1615 {
1616         int invalid_import = 0;
1617         ENTRY;
1618
1619         /* if we have an invalid import we want to drain the queued pages
1620          * by forcing them through rpcs that immediately fail and complete
1621          * the pages.  recovery relies on this to empty the queued pages
1622          * before canceling the locks and evicting down the llite pages */
1623         if ((cli->cl_import == NULL || cli->cl_import->imp_invalid))
1624                 invalid_import = 1;
1625
1626         if (cmd & OBD_BRW_WRITE) {
1627                 if (cfs_atomic_read(&osc->oo_nr_writes) == 0)
1628                         RETURN(0);
1629                 if (invalid_import) {
1630                         CDEBUG(D_CACHE, "invalid import forcing RPC\n");
1631                         RETURN(1);
1632                 }
1633                 if (!cfs_list_empty(&osc->oo_hp_exts)) {
1634                         CDEBUG(D_CACHE, "high prio request forcing RPC\n");
1635                         RETURN(1);
1636                 }
1637                 if (!cfs_list_empty(&osc->oo_urgent_exts)) {
1638                         CDEBUG(D_CACHE, "urgent request forcing RPC\n");
1639                         RETURN(1);
1640                 }
1641                 /* trigger a write rpc stream as long as there are dirtiers
1642                  * waiting for space.  as they're waiting, they're not going to
1643                  * create more pages to coalesce with what's waiting.. */
1644                 if (!cfs_list_empty(&cli->cl_cache_waiters)) {
1645                         CDEBUG(D_CACHE, "cache waiters forcing RPC\n");
1646                         RETURN(1);
1647                 }
1648                 if (cfs_atomic_read(&osc->oo_nr_writes) >=
1649                     cli->cl_max_pages_per_rpc)
1650                         RETURN(1);
1651         } else {
1652                 if (cfs_atomic_read(&osc->oo_nr_reads) == 0)
1653                         RETURN(0);
1654                 if (invalid_import) {
1655                         CDEBUG(D_CACHE, "invalid import forcing RPC\n");
1656                         RETURN(1);
1657                 }
1658                 /* all read are urgent. */
1659                 if (!cfs_list_empty(&osc->oo_reading_exts))
1660                         RETURN(1);
1661         }
1662
1663         RETURN(0);
1664 }
1665
1666 static void osc_update_pending(struct osc_object *obj, int cmd, int delta)
1667 {
1668         struct client_obd *cli = osc_cli(obj);
1669         if (cmd & OBD_BRW_WRITE) {
1670                 cfs_atomic_add(delta, &obj->oo_nr_writes);
1671                 cfs_atomic_add(delta, &cli->cl_pending_w_pages);
1672                 LASSERT(cfs_atomic_read(&obj->oo_nr_writes) >= 0);
1673         } else {
1674                 cfs_atomic_add(delta, &obj->oo_nr_reads);
1675                 cfs_atomic_add(delta, &cli->cl_pending_r_pages);
1676                 LASSERT(cfs_atomic_read(&obj->oo_nr_reads) >= 0);
1677         }
1678         OSC_IO_DEBUG(obj, "update pending cmd %d delta %d.\n", cmd, delta);
1679 }
1680
1681 static int osc_makes_hprpc(struct osc_object *obj)
1682 {
1683         return !cfs_list_empty(&obj->oo_hp_exts);
1684 }
1685
1686 static void on_list(cfs_list_t *item, cfs_list_t *list, int should_be_on)
1687 {
1688         if (cfs_list_empty(item) && should_be_on)
1689                 cfs_list_add_tail(item, list);
1690         else if (!cfs_list_empty(item) && !should_be_on)
1691                 cfs_list_del_init(item);
1692 }
1693
1694 /* maintain the osc's cli list membership invariants so that osc_send_oap_rpc
1695  * can find pages to build into rpcs quickly */
1696 static int __osc_list_maint(struct client_obd *cli, struct osc_object *osc)
1697 {
1698         if (osc_makes_hprpc(osc)) {
1699                 /* HP rpc */
1700                 on_list(&osc->oo_ready_item, &cli->cl_loi_ready_list, 0);
1701                 on_list(&osc->oo_hp_ready_item, &cli->cl_loi_hp_ready_list, 1);
1702         } else {
1703                 on_list(&osc->oo_hp_ready_item, &cli->cl_loi_hp_ready_list, 0);
1704                 on_list(&osc->oo_ready_item, &cli->cl_loi_ready_list,
1705                         osc_makes_rpc(cli, osc, OBD_BRW_WRITE) ||
1706                         osc_makes_rpc(cli, osc, OBD_BRW_READ));
1707         }
1708
1709         on_list(&osc->oo_write_item, &cli->cl_loi_write_list,
1710                 cfs_atomic_read(&osc->oo_nr_writes) > 0);
1711
1712         on_list(&osc->oo_read_item, &cli->cl_loi_read_list,
1713                 cfs_atomic_read(&osc->oo_nr_reads) > 0);
1714
1715         return osc_is_ready(osc);
1716 }
1717
1718 static int osc_list_maint(struct client_obd *cli, struct osc_object *osc)
1719 {
1720         int is_ready;
1721
1722         client_obd_list_lock(&cli->cl_loi_list_lock);
1723         is_ready = __osc_list_maint(cli, osc);
1724         client_obd_list_unlock(&cli->cl_loi_list_lock);
1725
1726         return is_ready;
1727 }
1728
1729 /* this is trying to propogate async writeback errors back up to the
1730  * application.  As an async write fails we record the error code for later if
1731  * the app does an fsync.  As long as errors persist we force future rpcs to be
1732  * sync so that the app can get a sync error and break the cycle of queueing
1733  * pages for which writeback will fail. */
1734 static void osc_process_ar(struct osc_async_rc *ar, __u64 xid,
1735                            int rc)
1736 {
1737         if (rc) {
1738                 if (!ar->ar_rc)
1739                         ar->ar_rc = rc;
1740
1741                 ar->ar_force_sync = 1;
1742                 ar->ar_min_xid = ptlrpc_sample_next_xid();
1743                 return;
1744
1745         }
1746
1747         if (ar->ar_force_sync && (xid >= ar->ar_min_xid))
1748                 ar->ar_force_sync = 0;
1749 }
1750
1751 /* this must be called holding the loi list lock to give coverage to exit_cache,
1752  * async_flag maintenance, and oap_request */
1753 static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
1754                               struct osc_async_page *oap, int sent, int rc)
1755 {
1756         struct osc_object *osc = oap->oap_obj;
1757         struct lov_oinfo  *loi = osc->oo_oinfo;
1758         __u64 xid = 0;
1759
1760         ENTRY;
1761         if (oap->oap_request != NULL) {
1762                 xid = ptlrpc_req_xid(oap->oap_request);
1763                 ptlrpc_req_finished(oap->oap_request);
1764                 oap->oap_request = NULL;
1765         }
1766
1767         /* As the transfer for this page is being done, clear the flags */
1768         spin_lock(&oap->oap_lock);
1769         oap->oap_async_flags = 0;
1770         spin_unlock(&oap->oap_lock);
1771         oap->oap_interrupted = 0;
1772
1773         if (oap->oap_cmd & OBD_BRW_WRITE && xid > 0) {
1774                 client_obd_list_lock(&cli->cl_loi_list_lock);
1775                 osc_process_ar(&cli->cl_ar, xid, rc);
1776                 osc_process_ar(&loi->loi_ar, xid, rc);
1777                 client_obd_list_unlock(&cli->cl_loi_list_lock);
1778         }
1779
1780         rc = osc_completion(env, oap, oap->oap_cmd, rc);
1781         if (rc)
1782                 CERROR("completion on oap %p obj %p returns %d.\n",
1783                        oap, osc, rc);
1784
1785         EXIT;
1786 }
1787
1788 /**
1789  * Try to add extent to one RPC. We need to think about the following things:
1790  * - # of pages must not be over max_pages_per_rpc
1791  * - extent must be compatible with previous ones
1792  */
1793 static int try_to_add_extent_for_io(struct client_obd *cli,
1794                                     struct osc_extent *ext, cfs_list_t *rpclist,
1795                                     int *pc, unsigned int *max_pages)
1796 {
1797         struct osc_extent *tmp;
1798         ENTRY;
1799
1800         EASSERT((ext->oe_state == OES_CACHE || ext->oe_state == OES_LOCK_DONE),
1801                 ext);
1802
1803         *max_pages = max(ext->oe_mppr, *max_pages);
1804         if (*pc + ext->oe_nr_pages > *max_pages)
1805                 RETURN(0);
1806
1807         cfs_list_for_each_entry(tmp, rpclist, oe_link) {
1808                 EASSERT(tmp->oe_owner == cfs_current(), tmp);
1809 #if 0
1810                 if (overlapped(tmp, ext)) {
1811                         OSC_EXTENT_DUMP(D_ERROR, tmp, "overlapped %p.\n", ext);
1812                         EASSERT(0, ext);
1813                 }
1814 #endif
1815
1816                 if (tmp->oe_srvlock != ext->oe_srvlock ||
1817                     !tmp->oe_grants != !ext->oe_grants)
1818                         RETURN(0);
1819
1820                 /* remove break for strict check */
1821                 break;
1822         }
1823
1824         *pc += ext->oe_nr_pages;
1825         cfs_list_move_tail(&ext->oe_link, rpclist);
1826         ext->oe_owner = cfs_current();
1827         RETURN(1);
1828 }
1829
1830 /**
1831  * In order to prevent multiple ptlrpcd from breaking contiguous extents,
1832  * get_write_extent() takes all appropriate extents in atomic.
1833  *
1834  * The following policy is used to collect extents for IO:
1835  * 1. Add as many HP extents as possible;
1836  * 2. Add the first urgent extent in urgent extent list and take it out of
1837  *    urgent list;
1838  * 3. Add subsequent extents of this urgent extent;
1839  * 4. If urgent list is not empty, goto 2;
1840  * 5. Traverse the extent tree from the 1st extent;
1841  * 6. Above steps exit if there is no space in this RPC.
1842  */
1843 static int get_write_extents(struct osc_object *obj, cfs_list_t *rpclist)
1844 {
1845         struct client_obd *cli = osc_cli(obj);
1846         struct osc_extent *ext;
1847         int page_count = 0;
1848         unsigned int max_pages = cli->cl_max_pages_per_rpc;
1849
1850         LASSERT(osc_object_is_locked(obj));
1851         while (!cfs_list_empty(&obj->oo_hp_exts)) {
1852                 ext = cfs_list_entry(obj->oo_hp_exts.next, struct osc_extent,
1853                                      oe_link);
1854                 LASSERT(ext->oe_state == OES_CACHE);
1855                 if (!try_to_add_extent_for_io(cli, ext, rpclist, &page_count,
1856                                               &max_pages))
1857                         return page_count;
1858                 EASSERT(ext->oe_nr_pages <= max_pages, ext);
1859         }
1860         if (page_count == max_pages)
1861                 return page_count;
1862
1863         while (!cfs_list_empty(&obj->oo_urgent_exts)) {
1864                 ext = cfs_list_entry(obj->oo_urgent_exts.next,
1865                                      struct osc_extent, oe_link);
1866                 if (!try_to_add_extent_for_io(cli, ext, rpclist, &page_count,
1867                                               &max_pages))
1868                         return page_count;
1869
1870                 if (!ext->oe_intree)
1871                         continue;
1872
1873                 while ((ext = next_extent(ext)) != NULL) {
1874                         if ((ext->oe_state != OES_CACHE) ||
1875                             (!cfs_list_empty(&ext->oe_link) &&
1876                              ext->oe_owner != NULL))
1877                                 continue;
1878
1879                         if (!try_to_add_extent_for_io(cli, ext, rpclist,
1880                                                       &page_count, &max_pages))
1881                                 return page_count;
1882                 }
1883         }
1884         if (page_count == max_pages)
1885                 return page_count;
1886
1887         ext = first_extent(obj);
1888         while (ext != NULL) {
1889                 if ((ext->oe_state != OES_CACHE) ||
1890                     /* this extent may be already in current rpclist */
1891                     (!cfs_list_empty(&ext->oe_link) && ext->oe_owner != NULL)) {
1892                         ext = next_extent(ext);
1893                         continue;
1894                 }
1895
1896                 if (!try_to_add_extent_for_io(cli, ext, rpclist, &page_count,
1897                                               &max_pages))
1898                         return page_count;
1899
1900                 ext = next_extent(ext);
1901         }
1902         return page_count;
1903 }
1904
1905 static int
1906 osc_send_write_rpc(const struct lu_env *env, struct client_obd *cli,
1907                    struct osc_object *osc, pdl_policy_t pol)
1908 {
1909         CFS_LIST_HEAD(rpclist);
1910         struct osc_extent *ext;
1911         struct osc_extent *tmp;
1912         struct osc_extent *first = NULL;
1913         obd_count page_count = 0;
1914         int srvlock = 0;
1915         int rc = 0;
1916         ENTRY;
1917
1918         LASSERT(osc_object_is_locked(osc));
1919
1920         page_count = get_write_extents(osc, &rpclist);
1921         LASSERT(equi(page_count == 0, cfs_list_empty(&rpclist)));
1922
1923         if (cfs_list_empty(&rpclist))
1924                 RETURN(0);
1925
1926         osc_update_pending(osc, OBD_BRW_WRITE, -page_count);
1927
1928         cfs_list_for_each_entry(ext, &rpclist, oe_link) {
1929                 LASSERT(ext->oe_state == OES_CACHE ||
1930                         ext->oe_state == OES_LOCK_DONE);
1931                 if (ext->oe_state == OES_CACHE)
1932                         osc_extent_state_set(ext, OES_LOCKING);
1933                 else
1934                         osc_extent_state_set(ext, OES_RPC);
1935         }
1936
1937         /* we're going to grab page lock, so release object lock because
1938          * lock order is page lock -> object lock. */
1939         osc_object_unlock(osc);
1940
1941         cfs_list_for_each_entry_safe(ext, tmp, &rpclist, oe_link) {
1942                 if (ext->oe_state == OES_LOCKING) {
1943                         rc = osc_extent_make_ready(env, ext);
1944                         if (unlikely(rc < 0)) {
1945                                 cfs_list_del_init(&ext->oe_link);
1946                                 osc_extent_finish(env, ext, 0, rc);
1947                                 continue;
1948                         }
1949                 }
1950                 if (first == NULL) {
1951                         first = ext;
1952                         srvlock = ext->oe_srvlock;
1953                 } else {
1954                         LASSERT(srvlock == ext->oe_srvlock);
1955                 }
1956         }
1957
1958         if (!cfs_list_empty(&rpclist)) {
1959                 LASSERT(page_count > 0);
1960                 rc = osc_build_rpc(env, cli, &rpclist, OBD_BRW_WRITE, pol);
1961                 LASSERT(cfs_list_empty(&rpclist));
1962         }
1963
1964         osc_object_lock(osc);
1965         RETURN(rc);
1966 }
1967
1968 /**
1969  * prepare pages for ASYNC io and put pages in send queue.
1970  *
1971  * \param cmd OBD_BRW_* macroses
1972  * \param lop pending pages
1973  *
1974  * \return zero if no page added to send queue.
1975  * \return 1 if pages successfully added to send queue.
1976  * \return negative on errors.
1977  */
1978 static int
1979 osc_send_read_rpc(const struct lu_env *env, struct client_obd *cli,
1980                   struct osc_object *osc, pdl_policy_t pol)
1981 {
1982         struct osc_extent *ext;
1983         struct osc_extent *next;
1984         CFS_LIST_HEAD(rpclist);
1985         int page_count = 0;
1986         unsigned int max_pages = cli->cl_max_pages_per_rpc;
1987         int rc = 0;
1988         ENTRY;
1989
1990         LASSERT(osc_object_is_locked(osc));
1991         cfs_list_for_each_entry_safe(ext, next,
1992                                      &osc->oo_reading_exts, oe_link) {
1993                 EASSERT(ext->oe_state == OES_LOCK_DONE, ext);
1994                 if (!try_to_add_extent_for_io(cli, ext, &rpclist, &page_count,
1995                                               &max_pages))
1996                         break;
1997                 osc_extent_state_set(ext, OES_RPC);
1998                 EASSERT(ext->oe_nr_pages <= max_pages, ext);
1999         }
2000         LASSERT(page_count <= max_pages);
2001
2002         osc_update_pending(osc, OBD_BRW_READ, -page_count);
2003
2004         if (!cfs_list_empty(&rpclist)) {
2005                 osc_object_unlock(osc);
2006
2007                 LASSERT(page_count > 0);
2008                 rc = osc_build_rpc(env, cli, &rpclist, OBD_BRW_READ, pol);
2009                 LASSERT(cfs_list_empty(&rpclist));
2010
2011                 osc_object_lock(osc);
2012         }
2013         RETURN(rc);
2014 }
2015
2016 #define list_to_obj(list, item) ({                                            \
2017         cfs_list_t *__tmp = (list)->next;                                     \
2018         cfs_list_del_init(__tmp);                                             \
2019         cfs_list_entry(__tmp, struct osc_object, oo_##item);                  \
2020 })
2021
2022 /* This is called by osc_check_rpcs() to find which objects have pages that
2023  * we could be sending.  These lists are maintained by osc_makes_rpc(). */
2024 static struct osc_object *osc_next_obj(struct client_obd *cli)
2025 {
2026         ENTRY;
2027
2028         /* First return objects that have blocked locks so that they
2029          * will be flushed quickly and other clients can get the lock,
2030          * then objects which have pages ready to be stuffed into RPCs */
2031         if (!cfs_list_empty(&cli->cl_loi_hp_ready_list))
2032                 RETURN(list_to_obj(&cli->cl_loi_hp_ready_list, hp_ready_item));
2033         if (!cfs_list_empty(&cli->cl_loi_ready_list))
2034                 RETURN(list_to_obj(&cli->cl_loi_ready_list, ready_item));
2035
2036         /* then if we have cache waiters, return all objects with queued
2037          * writes.  This is especially important when many small files
2038          * have filled up the cache and not been fired into rpcs because
2039          * they don't pass the nr_pending/object threshhold */
2040         if (!cfs_list_empty(&cli->cl_cache_waiters) &&
2041             !cfs_list_empty(&cli->cl_loi_write_list))
2042                 RETURN(list_to_obj(&cli->cl_loi_write_list, write_item));
2043
2044         /* then return all queued objects when we have an invalid import
2045          * so that they get flushed */
2046         if (cli->cl_import == NULL || cli->cl_import->imp_invalid) {
2047                 if (!cfs_list_empty(&cli->cl_loi_write_list))
2048                         RETURN(list_to_obj(&cli->cl_loi_write_list,
2049                                            write_item));
2050                 if (!cfs_list_empty(&cli->cl_loi_read_list))
2051                         RETURN(list_to_obj(&cli->cl_loi_read_list,
2052                                            read_item));
2053         }
2054         RETURN(NULL);
2055 }
2056
2057 /* called with the loi list lock held */
2058 static void osc_check_rpcs(const struct lu_env *env, struct client_obd *cli,
2059                            pdl_policy_t pol)
2060 {
2061         struct osc_object *osc;
2062         int rc = 0;
2063         ENTRY;
2064
2065         while ((osc = osc_next_obj(cli)) != NULL) {
2066                 struct cl_object *obj = osc2cl(osc);
2067                 struct lu_ref_link link;
2068
2069                 OSC_IO_DEBUG(osc, "%lu in flight\n", rpcs_in_flight(cli));
2070
2071                 if (osc_max_rpc_in_flight(cli, osc)) {
2072                         __osc_list_maint(cli, osc);
2073                         break;
2074                 }
2075
2076                 cl_object_get(obj);
2077                 client_obd_list_unlock(&cli->cl_loi_list_lock);
2078                 lu_object_ref_add_at(&obj->co_lu, &link, "check",
2079                                      cfs_current());
2080
2081                 /* attempt some read/write balancing by alternating between
2082                  * reads and writes in an object.  The makes_rpc checks here
2083                  * would be redundant if we were getting read/write work items
2084                  * instead of objects.  we don't want send_oap_rpc to drain a
2085                  * partial read pending queue when we're given this object to
2086                  * do io on writes while there are cache waiters */
2087                 osc_object_lock(osc);
2088                 if (osc_makes_rpc(cli, osc, OBD_BRW_WRITE)) {
2089                         rc = osc_send_write_rpc(env, cli, osc, pol);
2090                         if (rc < 0) {
2091                                 CERROR("Write request failed with %d\n", rc);
2092
2093                                 /* osc_send_write_rpc failed, mostly because of
2094                                  * memory pressure.
2095                                  *
2096                                  * It can't break here, because if:
2097                                  *  - a page was submitted by osc_io_submit, so
2098                                  *    page locked;
2099                                  *  - no request in flight
2100                                  *  - no subsequent request
2101                                  * The system will be in live-lock state,
2102                                  * because there is no chance to call
2103                                  * osc_io_unplug() and osc_check_rpcs() any
2104                                  * more. pdflush can't help in this case,
2105                                  * because it might be blocked at grabbing
2106                                  * the page lock as we mentioned.
2107                                  *
2108                                  * Anyway, continue to drain pages. */
2109                                 /* break; */
2110                         }
2111                 }
2112                 if (osc_makes_rpc(cli, osc, OBD_BRW_READ)) {
2113                         rc = osc_send_read_rpc(env, cli, osc, pol);
2114                         if (rc < 0)
2115                                 CERROR("Read request failed with %d\n", rc);
2116                 }
2117                 osc_object_unlock(osc);
2118
2119                 osc_list_maint(cli, osc);
2120                 lu_object_ref_del_at(&obj->co_lu, &link, "check",
2121                                      cfs_current());
2122                 cl_object_put(env, obj);
2123
2124                 client_obd_list_lock(&cli->cl_loi_list_lock);
2125         }
2126 }
2127
2128 static int osc_io_unplug0(const struct lu_env *env, struct client_obd *cli,
2129                           struct osc_object *osc, pdl_policy_t pol, int async)
2130 {
2131         int rc = 0;
2132
2133         if (osc != NULL && osc_list_maint(cli, osc) == 0)
2134                 return 0;
2135
2136         if (!async) {
2137                 /* disable osc_lru_shrink() temporarily to avoid
2138                  * potential stack overrun problem. LU-2859 */
2139                 cfs_atomic_inc(&cli->cl_lru_shrinkers);
2140                 client_obd_list_lock(&cli->cl_loi_list_lock);
2141                 osc_check_rpcs(env, cli, pol);
2142                 client_obd_list_unlock(&cli->cl_loi_list_lock);
2143                 cfs_atomic_dec(&cli->cl_lru_shrinkers);
2144         } else {
2145                 CDEBUG(D_CACHE, "Queue writeback work for client %p.\n", cli);
2146                 LASSERT(cli->cl_writeback_work != NULL);
2147                 rc = ptlrpcd_queue_work(cli->cl_writeback_work);
2148         }
2149         return rc;
2150 }
2151
2152 static int osc_io_unplug_async(const struct lu_env *env,
2153                                 struct client_obd *cli, struct osc_object *osc)
2154 {
2155         /* XXX: policy is no use actually. */
2156         return osc_io_unplug0(env, cli, osc, PDL_POLICY_ROUND, 1);
2157 }
2158
2159 void osc_io_unplug(const struct lu_env *env, struct client_obd *cli,
2160                    struct osc_object *osc, pdl_policy_t pol)
2161 {
2162         (void)osc_io_unplug0(env, cli, osc, pol, 0);
2163 }
2164
2165 int osc_prep_async_page(struct osc_object *osc, struct osc_page *ops,
2166                         struct page *page, loff_t offset)
2167 {
2168         struct obd_export     *exp = osc_export(osc);
2169         struct osc_async_page *oap = &ops->ops_oap;
2170         ENTRY;
2171
2172         if (!page)
2173                 return cfs_size_round(sizeof(*oap));
2174
2175         oap->oap_magic = OAP_MAGIC;
2176         oap->oap_cli = &exp->exp_obd->u.cli;
2177         oap->oap_obj = osc;
2178
2179         oap->oap_page = page;
2180         oap->oap_obj_off = offset;
2181         LASSERT(!(offset & ~CFS_PAGE_MASK));
2182
2183         if (!client_is_remote(exp) && cfs_capable(CFS_CAP_SYS_RESOURCE))
2184                 oap->oap_brw_flags = OBD_BRW_NOQUOTA;
2185
2186         CFS_INIT_LIST_HEAD(&oap->oap_pending_item);
2187         CFS_INIT_LIST_HEAD(&oap->oap_rpc_item);
2188
2189         spin_lock_init(&oap->oap_lock);
2190         CDEBUG(D_INFO, "oap %p page %p obj off "LPU64"\n",
2191                oap, page, oap->oap_obj_off);
2192         RETURN(0);
2193 }
2194
2195 int osc_queue_async_io(const struct lu_env *env, struct cl_io *io,
2196                        struct osc_page *ops)
2197 {
2198         struct osc_io *oio = osc_env_io(env);
2199         struct osc_extent     *ext = NULL;
2200         struct osc_async_page *oap = &ops->ops_oap;
2201         struct client_obd     *cli = oap->oap_cli;
2202         struct osc_object     *osc = oap->oap_obj;
2203         pgoff_t index;
2204         int    grants = 0;
2205         int    brw_flags = OBD_BRW_ASYNC;
2206         int    cmd = OBD_BRW_WRITE;
2207         int    need_release = 0;
2208         int    rc = 0;
2209         ENTRY;
2210
2211         if (oap->oap_magic != OAP_MAGIC)
2212                 RETURN(-EINVAL);
2213
2214         if (cli->cl_import == NULL || cli->cl_import->imp_invalid)
2215                 RETURN(-EIO);
2216
2217         if (!cfs_list_empty(&oap->oap_pending_item) ||
2218             !cfs_list_empty(&oap->oap_rpc_item))
2219                 RETURN(-EBUSY);
2220
2221         /* Set the OBD_BRW_SRVLOCK before the page is queued. */
2222         brw_flags |= ops->ops_srvlock ? OBD_BRW_SRVLOCK : 0;
2223         if (!client_is_remote(osc_export(osc)) &&
2224             cfs_capable(CFS_CAP_SYS_RESOURCE)) {
2225                 brw_flags |= OBD_BRW_NOQUOTA;
2226                 cmd |= OBD_BRW_NOQUOTA;
2227         }
2228
2229         /* check if the file's owner/group is over quota */
2230         if (!(cmd & OBD_BRW_NOQUOTA)) {
2231                 struct cl_object *obj;
2232                 struct cl_attr   *attr;
2233                 unsigned int qid[MAXQUOTAS];
2234
2235                 obj = cl_object_top(&osc->oo_cl);
2236                 attr = &osc_env_info(env)->oti_attr;
2237
2238                 cl_object_attr_lock(obj);
2239                 rc = cl_object_attr_get(env, obj, attr);
2240                 cl_object_attr_unlock(obj);
2241
2242                 qid[USRQUOTA] = attr->cat_uid;
2243                 qid[GRPQUOTA] = attr->cat_gid;
2244                 if (rc == 0 && osc_quota_chkdq(cli, qid) == NO_QUOTA)
2245                         rc = -EDQUOT;
2246                 if (rc)
2247                         RETURN(rc);
2248         }
2249
2250         oap->oap_cmd = cmd;
2251         oap->oap_page_off = ops->ops_from;
2252         oap->oap_count = ops->ops_to - ops->ops_from;
2253         oap->oap_async_flags = 0;
2254         oap->oap_brw_flags = brw_flags;
2255
2256         OSC_IO_DEBUG(osc, "oap %p page %p added for cmd %d\n",
2257                      oap, oap->oap_page, oap->oap_cmd & OBD_BRW_RWMASK);
2258
2259         index = oap2cl_page(oap)->cp_index;
2260
2261         /* Add this page into extent by the following steps:
2262          * 1. if there exists an active extent for this IO, mostly this page
2263          *    can be added to the active extent and sometimes we need to
2264          *    expand extent to accomodate this page;
2265          * 2. otherwise, a new extent will be allocated. */
2266
2267         ext = oio->oi_active;
2268         if (ext != NULL && ext->oe_start <= index && ext->oe_max_end >= index) {
2269                 /* one chunk plus extent overhead must be enough to write this
2270                  * page */
2271                 grants = (1 << cli->cl_chunkbits) + cli->cl_extent_tax;
2272                 if (ext->oe_end >= index)
2273                         grants = 0;
2274
2275                 /* it doesn't need any grant to dirty this page */
2276                 client_obd_list_lock(&cli->cl_loi_list_lock);
2277                 rc = osc_enter_cache_try(cli, oap, grants, 0);
2278                 client_obd_list_unlock(&cli->cl_loi_list_lock);
2279                 if (rc == 0) { /* try failed */
2280                         grants = 0;
2281                         need_release = 1;
2282                 } else if (ext->oe_end < index) {
2283                         int tmp = grants;
2284                         /* try to expand this extent */
2285                         rc = osc_extent_expand(ext, index, &tmp);
2286                         if (rc < 0) {
2287                                 need_release = 1;
2288                                 /* don't free reserved grant */
2289                         } else {
2290                                 OSC_EXTENT_DUMP(D_CACHE, ext,
2291                                                 "expanded for %lu.\n", index);
2292                                 osc_unreserve_grant(cli, grants, tmp);
2293                                 grants = 0;
2294                         }
2295                 }
2296                 rc = 0;
2297         } else if (ext != NULL) {
2298                 /* index is located outside of active extent */
2299                 need_release = 1;
2300         }
2301         if (need_release) {
2302                 osc_extent_release(env, ext);
2303                 oio->oi_active = NULL;
2304                 ext = NULL;
2305         }
2306
2307         if (ext == NULL) {
2308                 int tmp = (1 << cli->cl_chunkbits) + cli->cl_extent_tax;
2309
2310                 /* try to find new extent to cover this page */
2311                 LASSERT(oio->oi_active == NULL);
2312                 /* we may have allocated grant for this page if we failed
2313                  * to expand the previous active extent. */
2314                 LASSERT(ergo(grants > 0, grants >= tmp));
2315
2316                 rc = 0;
2317                 if (grants == 0) {
2318                         /* we haven't allocated grant for this page. */
2319                         rc = osc_enter_cache(env, cli, oap, tmp);
2320                         if (rc == 0)
2321                                 grants = tmp;
2322                 }
2323
2324                 tmp = grants;
2325                 if (rc == 0) {
2326                         ext = osc_extent_find(env, osc, index, &tmp);
2327                         if (IS_ERR(ext)) {
2328                                 LASSERT(tmp == grants);
2329                                 osc_exit_cache(cli, oap);
2330                                 rc = PTR_ERR(ext);
2331                                 ext = NULL;
2332                         } else {
2333                                 oio->oi_active = ext;
2334                         }
2335                 }
2336                 if (grants > 0)
2337                         osc_unreserve_grant(cli, grants, tmp);
2338         }
2339
2340         LASSERT(ergo(rc == 0, ext != NULL));
2341         if (ext != NULL) {
2342                 EASSERTF(ext->oe_end >= index && ext->oe_start <= index,
2343                          ext, "index = %lu.\n", index);
2344                 LASSERT((oap->oap_brw_flags & OBD_BRW_FROM_GRANT) != 0);
2345
2346                 osc_object_lock(osc);
2347                 if (ext->oe_nr_pages == 0)
2348                         ext->oe_srvlock = ops->ops_srvlock;
2349                 else
2350                         LASSERT(ext->oe_srvlock == ops->ops_srvlock);
2351                 ++ext->oe_nr_pages;
2352                 cfs_list_add_tail(&oap->oap_pending_item, &ext->oe_pages);
2353                 osc_object_unlock(osc);
2354         }
2355         RETURN(rc);
2356 }
2357
2358 int osc_teardown_async_page(const struct lu_env *env,
2359                             struct osc_object *obj, struct osc_page *ops)
2360 {
2361         struct osc_async_page *oap = &ops->ops_oap;
2362         struct osc_extent     *ext = NULL;
2363         int rc = 0;
2364         ENTRY;
2365
2366         LASSERT(oap->oap_magic == OAP_MAGIC);
2367
2368         CDEBUG(D_INFO, "teardown oap %p page %p at index %lu.\n",
2369                oap, ops, oap2cl_page(oap)->cp_index);
2370
2371         osc_object_lock(obj);
2372         if (!cfs_list_empty(&oap->oap_rpc_item)) {
2373                 CDEBUG(D_CACHE, "oap %p is not in cache.\n", oap);
2374                 rc = -EBUSY;
2375         } else if (!cfs_list_empty(&oap->oap_pending_item)) {
2376                 ext = osc_extent_lookup(obj, oap2cl_page(oap)->cp_index);
2377                 /* only truncated pages are allowed to be taken out.
2378                  * See osc_extent_truncate() and osc_cache_truncate_start()
2379                  * for details. */
2380                 if (ext != NULL && ext->oe_state != OES_TRUNC) {
2381                         OSC_EXTENT_DUMP(D_ERROR, ext, "trunc at %lu.\n",
2382                                         oap2cl_page(oap)->cp_index);
2383                         rc = -EBUSY;
2384                 }
2385         }
2386         osc_object_unlock(obj);
2387         if (ext != NULL)
2388                 osc_extent_put(env, ext);
2389         RETURN(rc);
2390 }
2391
2392 /**
2393  * This is called when a page is picked up by kernel to write out.
2394  *
2395  * We should find out the corresponding extent and add the whole extent
2396  * into urgent list. The extent may be being truncated or used, handle it
2397  * carefully.
2398  */
2399 int osc_flush_async_page(const struct lu_env *env, struct cl_io *io,
2400                          struct osc_page *ops)
2401 {
2402         struct osc_extent *ext   = NULL;
2403         struct osc_object *obj   = cl2osc(ops->ops_cl.cpl_obj);
2404         struct cl_page    *cp    = ops->ops_cl.cpl_page;
2405         pgoff_t            index = cp->cp_index;
2406         struct osc_async_page *oap = &ops->ops_oap;
2407         bool unplug = false;
2408         int rc = 0;
2409         ENTRY;
2410
2411         osc_object_lock(obj);
2412         ext = osc_extent_lookup(obj, index);
2413         if (ext == NULL) {
2414                 osc_extent_tree_dump(D_ERROR, obj);
2415                 LASSERTF(0, "page index %lu is NOT covered.\n", index);
2416         }
2417
2418         switch (ext->oe_state) {
2419         case OES_RPC:
2420         case OES_LOCK_DONE:
2421                 CL_PAGE_DEBUG(D_ERROR, env, cl_page_top(cp),
2422                               "flush an in-rpc page?\n");
2423                 LASSERT(0);
2424                 break;
2425         case OES_LOCKING:
2426                 /* If we know this extent is being written out, we should abort
2427                  * so that the writer can make this page ready. Otherwise, there
2428                  * exists a deadlock problem because other process can wait for
2429                  * page writeback bit holding page lock; and meanwhile in
2430                  * vvp_page_make_ready(), we need to grab page lock before
2431                  * really sending the RPC. */
2432         case OES_TRUNC:
2433                 /* race with truncate, page will be redirtied */
2434                 GOTO(out, rc = -EAGAIN);
2435         default:
2436                 break;
2437         }
2438
2439         rc = cl_page_prep(env, io, cl_page_top(cp), CRT_WRITE);
2440         if (rc)
2441                 GOTO(out, rc);
2442
2443         spin_lock(&oap->oap_lock);
2444         oap->oap_async_flags |= ASYNC_READY|ASYNC_URGENT;
2445         spin_unlock(&oap->oap_lock);
2446
2447         if (memory_pressure_get())
2448                 ext->oe_memalloc = 1;
2449
2450         ext->oe_urgent = 1;
2451         if (ext->oe_state == OES_CACHE) {
2452                 OSC_EXTENT_DUMP(D_CACHE, ext,
2453                                 "flush page %p make it urgent.\n", oap);
2454                 if (cfs_list_empty(&ext->oe_link))
2455                         cfs_list_add_tail(&ext->oe_link, &obj->oo_urgent_exts);
2456                 unplug = true;
2457         }
2458         rc = 0;
2459         EXIT;
2460
2461 out:
2462         osc_object_unlock(obj);
2463         osc_extent_put(env, ext);
2464         if (unplug)
2465                 osc_io_unplug_async(env, osc_cli(obj), obj);
2466         return rc;
2467 }
2468
2469 /**
2470  * this is called when a sync waiter receives an interruption.  Its job is to
2471  * get the caller woken as soon as possible.  If its page hasn't been put in an
2472  * rpc yet it can dequeue immediately.  Otherwise it has to mark the rpc as
2473  * desiring interruption which will forcefully complete the rpc once the rpc
2474  * has timed out.
2475  */
2476 int osc_cancel_async_page(const struct lu_env *env, struct osc_page *ops)
2477 {
2478         struct osc_async_page *oap = &ops->ops_oap;
2479         struct osc_object     *obj = oap->oap_obj;
2480         struct client_obd     *cli = osc_cli(obj);
2481         struct osc_extent     *ext;
2482         struct osc_extent     *found = NULL;
2483         cfs_list_t            *plist;
2484         pgoff_t index = oap2cl_page(oap)->cp_index;
2485         int     rc = -EBUSY;
2486         int     cmd;
2487         ENTRY;
2488
2489         LASSERT(!oap->oap_interrupted);
2490         oap->oap_interrupted = 1;
2491
2492         /* Find out the caching extent */
2493         osc_object_lock(obj);
2494         if (oap->oap_cmd & OBD_BRW_WRITE) {
2495                 plist = &obj->oo_urgent_exts;
2496                 cmd   = OBD_BRW_WRITE;
2497         } else {
2498                 plist = &obj->oo_reading_exts;
2499                 cmd   = OBD_BRW_READ;
2500         }
2501         cfs_list_for_each_entry(ext, plist, oe_link) {
2502                 if (ext->oe_start <= index && ext->oe_end >= index) {
2503                         LASSERT(ext->oe_state == OES_LOCK_DONE);
2504                         /* For OES_LOCK_DONE state extent, it has already held
2505                          * a refcount for RPC. */
2506                         found = osc_extent_get(ext);
2507                         break;
2508                 }
2509         }
2510         if (found != NULL) {
2511                 cfs_list_del_init(&found->oe_link);
2512                 osc_update_pending(obj, cmd, -found->oe_nr_pages);
2513                 osc_object_unlock(obj);
2514
2515                 osc_extent_finish(env, found, 0, -EINTR);
2516                 osc_extent_put(env, found);
2517                 rc = 0;
2518         } else {
2519                 osc_object_unlock(obj);
2520                 /* ok, it's been put in an rpc. only one oap gets a request
2521                  * reference */
2522                 if (oap->oap_request != NULL) {
2523                         ptlrpc_mark_interrupted(oap->oap_request);
2524                         ptlrpcd_wake(oap->oap_request);
2525                         ptlrpc_req_finished(oap->oap_request);
2526                         oap->oap_request = NULL;
2527                 }
2528         }
2529
2530         osc_list_maint(cli, obj);
2531         RETURN(rc);
2532 }
2533
2534 int osc_queue_sync_pages(const struct lu_env *env, struct osc_object *obj,
2535                          cfs_list_t *list, int cmd, int brw_flags)
2536 {
2537         struct client_obd     *cli = osc_cli(obj);
2538         struct osc_extent     *ext;
2539         struct osc_async_page *oap;
2540         int     page_count = 0;
2541         int     mppr       = cli->cl_max_pages_per_rpc;
2542         pgoff_t start      = CL_PAGE_EOF;
2543         pgoff_t end        = 0;
2544         ENTRY;
2545
2546         cfs_list_for_each_entry(oap, list, oap_pending_item) {
2547                 struct cl_page *cp = oap2cl_page(oap);
2548                 if (cp->cp_index > end)
2549                         end = cp->cp_index;
2550                 if (cp->cp_index < start)
2551                         start = cp->cp_index;
2552                 ++page_count;
2553                 mppr <<= (page_count > mppr);
2554         }
2555
2556         ext = osc_extent_alloc(obj);
2557         if (ext == NULL) {
2558                 cfs_list_for_each_entry(oap, list, oap_pending_item) {
2559                         cfs_list_del_init(&oap->oap_pending_item);
2560                         osc_ap_completion(env, cli, oap, 0, -ENOMEM);
2561                 }
2562                 RETURN(-ENOMEM);
2563         }
2564
2565         ext->oe_rw = !!(cmd & OBD_BRW_READ);
2566         ext->oe_urgent = 1;
2567         ext->oe_start = start;
2568         ext->oe_end = ext->oe_max_end = end;
2569         ext->oe_obj = obj;
2570         ext->oe_srvlock = !!(brw_flags & OBD_BRW_SRVLOCK);
2571         ext->oe_nr_pages = page_count;
2572         ext->oe_mppr = mppr;
2573         cfs_list_splice_init(list, &ext->oe_pages);
2574
2575         osc_object_lock(obj);
2576         /* Reuse the initial refcount for RPC, don't drop it */
2577         osc_extent_state_set(ext, OES_LOCK_DONE);
2578         if (cmd & OBD_BRW_WRITE) {
2579                 cfs_list_add_tail(&ext->oe_link, &obj->oo_urgent_exts);
2580                 osc_update_pending(obj, OBD_BRW_WRITE, page_count);
2581         } else {
2582                 cfs_list_add_tail(&ext->oe_link, &obj->oo_reading_exts);
2583                 osc_update_pending(obj, OBD_BRW_READ, page_count);
2584         }
2585         osc_object_unlock(obj);
2586
2587         osc_io_unplug(env, cli, obj, PDL_POLICY_ROUND);
2588         RETURN(0);
2589 }
2590
2591 /**
2592  * Called by osc_io_setattr_start() to freeze and destroy covering extents.
2593  */
2594 int osc_cache_truncate_start(const struct lu_env *env, struct osc_io *oio,
2595                              struct osc_object *obj, __u64 size)
2596 {
2597         struct client_obd *cli = osc_cli(obj);
2598         struct osc_extent *ext;
2599         struct osc_extent *waiting = NULL;
2600         pgoff_t index;
2601         CFS_LIST_HEAD(list);
2602         int result = 0;
2603         bool partial;
2604         ENTRY;
2605
2606         /* pages with index greater or equal to index will be truncated. */
2607         index = cl_index(osc2cl(obj), size);
2608         partial = size > cl_offset(osc2cl(obj), index);
2609
2610 again:
2611         osc_object_lock(obj);
2612         ext = osc_extent_search(obj, index);
2613         if (ext == NULL)
2614                 ext = first_extent(obj);
2615         else if (ext->oe_end < index)
2616                 ext = next_extent(ext);
2617         while (ext != NULL) {
2618                 EASSERT(ext->oe_state != OES_TRUNC, ext);
2619
2620                 if (ext->oe_state > OES_CACHE || ext->oe_urgent) {
2621                         /* if ext is in urgent state, it means there must exist
2622                          * a page already having been flushed by write_page().
2623                          * We have to wait for this extent because we can't
2624                          * truncate that page. */
2625                         LASSERT(!ext->oe_hp);
2626                         OSC_EXTENT_DUMP(D_CACHE, ext,
2627                                         "waiting for busy extent\n");
2628                         waiting = osc_extent_get(ext);
2629                         break;
2630                 }
2631
2632                 OSC_EXTENT_DUMP(D_CACHE, ext, "try to trunc:"LPU64".\n", size);
2633
2634                 osc_extent_get(ext);
2635                 if (ext->oe_state == OES_ACTIVE) {
2636                         /* though we grab inode mutex for write path, but we
2637                          * release it before releasing extent(in osc_io_end()),
2638                          * so there is a race window that an extent is still
2639                          * in OES_ACTIVE when truncate starts. */
2640                         LASSERT(!ext->oe_trunc_pending);
2641                         ext->oe_trunc_pending = 1;
2642                 } else {
2643                         EASSERT(ext->oe_state == OES_CACHE, ext);
2644                         osc_extent_state_set(ext, OES_TRUNC);
2645                         osc_update_pending(obj, OBD_BRW_WRITE,
2646                                            -ext->oe_nr_pages);
2647                 }
2648                 EASSERT(cfs_list_empty(&ext->oe_link), ext);
2649                 cfs_list_add_tail(&ext->oe_link, &list);
2650
2651                 ext = next_extent(ext);
2652         }
2653         osc_object_unlock(obj);
2654
2655         osc_list_maint(cli, obj);
2656
2657         while (!cfs_list_empty(&list)) {
2658                 int rc;
2659
2660                 ext = cfs_list_entry(list.next, struct osc_extent, oe_link);
2661                 cfs_list_del_init(&ext->oe_link);
2662
2663                 /* extent may be in OES_ACTIVE state because inode mutex
2664                  * is released before osc_io_end() in file write case */
2665                 if (ext->oe_state != OES_TRUNC)
2666                         osc_extent_wait(env, ext, OES_TRUNC);
2667
2668                 rc = osc_extent_truncate(ext, index, partial);
2669                 if (rc < 0) {
2670                         if (result == 0)
2671                                 result = rc;
2672
2673                         OSC_EXTENT_DUMP(D_ERROR, ext,
2674                                         "truncate error %d\n", rc);
2675                 } else if (ext->oe_nr_pages == 0) {
2676                         osc_extent_remove(ext);
2677                 } else {
2678                         /* this must be an overlapped extent which means only
2679                          * part of pages in this extent have been truncated.
2680                          */
2681                         EASSERTF(ext->oe_start <= index, ext,
2682                                  "trunc index = %lu/%d.\n", index, partial);
2683                         /* fix index to skip this partially truncated extent */
2684                         index = ext->oe_end + 1;
2685                         partial = false;
2686
2687                         /* we need to hold this extent in OES_TRUNC state so
2688                          * that no writeback will happen. This is to avoid
2689                          * BUG 17397. */
2690                         LASSERT(oio->oi_trunc == NULL);
2691                         oio->oi_trunc = osc_extent_get(ext);
2692                         OSC_EXTENT_DUMP(D_CACHE, ext,
2693                                         "trunc at "LPU64"\n", size);
2694                 }
2695                 osc_extent_put(env, ext);
2696         }
2697         if (waiting != NULL) {
2698                 int rc;
2699
2700                 /* ignore the result of osc_extent_wait the write initiator
2701                  * should take care of it. */
2702                 rc = osc_extent_wait(env, waiting, OES_INV);
2703                 if (rc < 0)
2704                         OSC_EXTENT_DUMP(D_CACHE, waiting, "error: %d.\n", rc);
2705
2706                 osc_extent_put(env, waiting);
2707                 waiting = NULL;
2708                 goto again;
2709         }
2710         RETURN(result);
2711 }
2712
2713 /**
2714  * Called after osc_io_setattr_end to add oio->oi_trunc back to cache.
2715  */
2716 void osc_cache_truncate_end(const struct lu_env *env, struct osc_io *oio,
2717                             struct osc_object *obj)
2718 {
2719         struct osc_extent *ext = oio->oi_trunc;
2720
2721         oio->oi_trunc = NULL;
2722         if (ext != NULL) {
2723                 bool unplug = false;
2724
2725                 EASSERT(ext->oe_nr_pages > 0, ext);
2726                 EASSERT(ext->oe_state == OES_TRUNC, ext);
2727                 EASSERT(!ext->oe_urgent, ext);
2728
2729                 OSC_EXTENT_DUMP(D_CACHE, ext, "trunc -> cache.\n");
2730                 osc_object_lock(obj);
2731                 osc_extent_state_set(ext, OES_CACHE);
2732                 if (ext->oe_fsync_wait && !ext->oe_urgent) {
2733                         ext->oe_urgent = 1;
2734                         cfs_list_move_tail(&ext->oe_link, &obj->oo_urgent_exts);
2735                         unplug = true;
2736                 }
2737                 osc_update_pending(obj, OBD_BRW_WRITE, ext->oe_nr_pages);
2738                 osc_object_unlock(obj);
2739                 osc_extent_put(env, ext);
2740
2741                 if (unplug)
2742                         osc_io_unplug_async(env, osc_cli(obj), obj);
2743         }
2744 }
2745
2746 /**
2747  * Wait for extents in a specific range to be written out.
2748  * The caller must have called osc_cache_writeback_range() to issue IO
2749  * otherwise it will take a long time for this function to finish.
2750  *
2751  * Caller must hold inode_mutex , or cancel exclusive dlm lock so that
2752  * nobody else can dirty this range of file while we're waiting for
2753  * extents to be written.
2754  */
2755 int osc_cache_wait_range(const struct lu_env *env, struct osc_object *obj,
2756                          pgoff_t start, pgoff_t end)
2757 {
2758         struct osc_extent *ext;
2759         pgoff_t index = start;
2760         int     result = 0;
2761         ENTRY;
2762
2763 again:
2764         osc_object_lock(obj);
2765         ext = osc_extent_search(obj, index);
2766         if (ext == NULL)
2767                 ext = first_extent(obj);
2768         else if (ext->oe_end < index)
2769                 ext = next_extent(ext);
2770         while (ext != NULL) {
2771                 int rc;
2772
2773                 if (ext->oe_start > end)
2774                         break;
2775
2776                 if (!ext->oe_fsync_wait) {
2777                         ext = next_extent(ext);
2778                         continue;
2779                 }
2780
2781                 EASSERT(ergo(ext->oe_state == OES_CACHE,
2782                              ext->oe_hp || ext->oe_urgent), ext);
2783                 EASSERT(ergo(ext->oe_state == OES_ACTIVE,
2784                              !ext->oe_hp && ext->oe_urgent), ext);
2785
2786                 index = ext->oe_end + 1;
2787                 osc_extent_get(ext);
2788                 osc_object_unlock(obj);
2789
2790                 rc = osc_extent_wait(env, ext, OES_INV);
2791                 if (result == 0)
2792                         result = rc;
2793                 osc_extent_put(env, ext);
2794                 goto again;
2795         }
2796         osc_object_unlock(obj);
2797
2798         OSC_IO_DEBUG(obj, "sync file range.\n");
2799         RETURN(result);
2800 }
2801
2802 /**
2803  * Called to write out a range of osc object.
2804  *
2805  * @hp     : should be set this is caused by lock cancel;
2806  * @discard: is set if dirty pages should be dropped - file will be deleted or
2807  *         truncated, this implies there is no partially discarding extents.
2808  *
2809  * Return how many pages will be issued, or error code if error occurred.
2810  */
2811 int osc_cache_writeback_range(const struct lu_env *env, struct osc_object *obj,
2812                               pgoff_t start, pgoff_t end, int hp, int discard)
2813 {
2814         struct osc_extent *ext;
2815         CFS_LIST_HEAD(discard_list);
2816         bool unplug = false;
2817         int result = 0;
2818         ENTRY;
2819
2820         osc_object_lock(obj);
2821         ext = osc_extent_search(obj, start);
2822         if (ext == NULL)
2823                 ext = first_extent(obj);
2824         else if (ext->oe_end < start)
2825                 ext = next_extent(ext);
2826         while (ext != NULL) {
2827                 if (ext->oe_start > end)
2828                         break;
2829
2830                 ext->oe_fsync_wait = 1;
2831                 switch (ext->oe_state) {
2832                 case OES_CACHE:
2833                         result += ext->oe_nr_pages;
2834                         if (!discard) {
2835                                 cfs_list_t *list = NULL;
2836                                 if (hp) {
2837                                         EASSERT(!ext->oe_hp, ext);
2838                                         ext->oe_hp = 1;
2839                                         list = &obj->oo_hp_exts;
2840                                 } else if (!ext->oe_urgent) {
2841                                         ext->oe_urgent = 1;
2842                                         list = &obj->oo_urgent_exts;
2843                                 }
2844                                 if (list != NULL)
2845                                         cfs_list_move_tail(&ext->oe_link, list);
2846                                 unplug = true;
2847                         } else {
2848                                 /* the only discarder is lock cancelling, so
2849                                  * [start, end] must contain this extent */
2850                                 EASSERT(ext->oe_start >= start &&
2851                                         ext->oe_max_end <= end, ext);
2852                                 osc_extent_state_set(ext, OES_LOCKING);
2853                                 ext->oe_owner = cfs_current();
2854                                 cfs_list_move_tail(&ext->oe_link,
2855                                                    &discard_list);
2856                                 osc_update_pending(obj, OBD_BRW_WRITE,
2857                                                    -ext->oe_nr_pages);
2858                         }
2859                         break;
2860                 case OES_ACTIVE:
2861                         /* It's pretty bad to wait for ACTIVE extents, because
2862                          * we don't know how long we will wait for it to be
2863                          * flushed since it may be blocked at awaiting more
2864                          * grants. We do this for the correctness of fsync. */
2865                         LASSERT(hp == 0 && discard == 0);
2866                         ext->oe_urgent = 1;
2867                         break;
2868                 case OES_TRUNC:
2869                         /* this extent is being truncated, can't do anything
2870                          * for it now. it will be set to urgent after truncate
2871                          * is finished in osc_cache_truncate_end(). */
2872                 default:
2873                         break;
2874                 }
2875                 ext = next_extent(ext);
2876         }
2877         osc_object_unlock(obj);
2878
2879         LASSERT(ergo(!discard, cfs_list_empty(&discard_list)));
2880         if (!cfs_list_empty(&discard_list)) {
2881                 struct osc_extent *tmp;
2882                 int rc;
2883
2884                 osc_list_maint(osc_cli(obj), obj);
2885                 cfs_list_for_each_entry_safe(ext, tmp, &discard_list, oe_link) {
2886                         cfs_list_del_init(&ext->oe_link);
2887                         EASSERT(ext->oe_state == OES_LOCKING, ext);
2888
2889                         /* Discard caching pages. We don't actually write this
2890                          * extent out but we complete it as if we did. */
2891                         rc = osc_extent_make_ready(env, ext);
2892                         if (unlikely(rc < 0)) {
2893                                 OSC_EXTENT_DUMP(D_ERROR, ext,
2894                                                 "make_ready returned %d\n", rc);
2895                                 if (result >= 0)
2896                                         result = rc;
2897                         }
2898
2899                         /* finish the extent as if the pages were sent */
2900                         osc_extent_finish(env, ext, 0, 0);
2901                 }
2902         }
2903
2904         if (unplug)
2905                 osc_io_unplug(env, osc_cli(obj), obj, PDL_POLICY_ROUND);
2906
2907         if (hp || discard) {
2908                 int rc;
2909                 rc = osc_cache_wait_range(env, obj, start, end);
2910                 if (result >= 0 && rc < 0)
2911                         result = rc;
2912         }
2913
2914         OSC_IO_DEBUG(obj, "cache page out.\n");
2915         RETURN(result);
2916 }
2917
2918 /** @} osc */