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.gnu.org/licenses/gpl-2.0.html
  19  *
  20  * GPL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  24  * Use is subject to license terms.
  25  *
  26  * Copyright (c) 2012, 2016, Intel Corporation.
  27  *
  28  */
  29 /*
  30  * This file is part of Lustre, http://www.lustre.org/
  31  * Lustre is a trademark of Sun Microsystems, Inc.
  32  *
  33  * osc cache management.
  34  *
  35  * Author: Jinshan Xiong <jinshan.xiong@whamcloud.com>
  36  */
  37
  38 #define DEBUG_SUBSYSTEM S_OSC
  39
  40 #include <lustre_osc.h>
  41
  42 #include "osc_internal.h"
  43
  44 static int extent_debug; /* set it to be true for more debug */
  45
  46 static void osc_update_pending(struct osc_object *obj, int cmd, int delta);
  47 static int osc_extent_wait(const struct lu_env *env, struct osc_extent *ext,
  48                            enum osc_extent_state state);
  49 static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
  50                               struct osc_async_page *oap, int sent, int rc);
  51 static int osc_make_ready(const struct lu_env *env, struct osc_async_page *oap,
  52                           int cmd);
  53 static int osc_refresh_count(const struct lu_env *env,
  54                              struct osc_async_page *oap, int cmd);
  55 static int osc_io_unplug_async(const struct lu_env *env,
  56                                struct client_obd *cli, struct osc_object *osc);
  57 static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
  58                            unsigned int lost_grant, unsigned int dirty_grant);
  59
  60 static void osc_extent_tree_dump0(int level, struct osc_object *obj,
  61                                   const char *func, int line);
  62 #define osc_extent_tree_dump(lvl, obj) \
  63         osc_extent_tree_dump0(lvl, obj, __func__, __LINE__)
  64
  65 static void osc_unreserve_grant(struct client_obd *cli, unsigned int reserved,
  66                                 unsigned int unused);
  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_sync)
  80                 *buf++ = 'S';
  81         if (ext->oe_srvlock)
  82                 *buf++ = 's';
  83         if (ext->oe_hp)
  84                 *buf++ = 'h';
  85         if (ext->oe_urgent)
  86                 *buf++ = 'u';
  87         if (ext->oe_memalloc)
  88                 *buf++ = 'm';
  89         if (ext->oe_trunc_pending)
  90                 *buf++ = 't';
  91         if (ext->oe_fsync_wait)
  92                 *buf++ = 'Y';
  93         *buf = 0;
  94         return flags;
  95 }
  96
  97 static inline char list_empty_marker(struct list_head *list)
  98 {
  99         return list_empty(list) ? '-' : '+';
 100 }
 101
 102 #define EXTSTR       "[%lu -> %lu/%lu]"
 103 #define EXTPARA(ext) (ext)->oe_start, (ext)->oe_end, (ext)->oe_max_end
 104 static const char *oes_strings[] = {
 105         "inv", "active", "cache", "locking", "lockdone", "rpc", "trunc", NULL };
 106
 107 #define OSC_EXTENT_DUMP(lvl, extent, fmt, ...) do {                           \
 108         struct osc_extent *__ext = (extent);                                  \
 109         char __buf[16];                                                       \
 110                                                                               \
 111         CDEBUG(lvl,                                                           \
 112                 "extent %p@{" EXTSTR ", "                                     \
 113                 "[%d|%d|%c|%s|%s|%p], [%d|%d|%c|%c|%p|%u|%p]} " fmt,          \
 114                 /* ----- extent part 0 ----- */                               \
 115                 __ext, EXTPARA(__ext),                                        \
 116                 /* ----- part 1 ----- */                                      \
 117                 atomic_read(&__ext->oe_refc),                         \
 118                 atomic_read(&__ext->oe_users),                        \
 119                 list_empty_marker(&__ext->oe_link),                           \
 120                 oes_strings[__ext->oe_state], ext_flags(__ext, __buf),        \
 121                 __ext->oe_obj,                                                \
 122                 /* ----- part 2 ----- */                                      \
 123                 __ext->oe_grants, __ext->oe_nr_pages,                         \
 124                 list_empty_marker(&__ext->oe_pages),                          \
 125                 waitqueue_active(&__ext->oe_waitq) ? '+' : '-',               \
 126                 __ext->oe_dlmlock, __ext->oe_mppr, __ext->oe_owner,           \
 127                 /* ----- part 4 ----- */                                      \
 128                 ## __VA_ARGS__);                                              \
 129         if (lvl == D_ERROR && __ext->oe_dlmlock != NULL)                      \
 130                 LDLM_ERROR(__ext->oe_dlmlock, "extent: %p", __ext);           \
 131         else                                                                  \
 132                 LDLM_DEBUG(__ext->oe_dlmlock, "extent: %p", __ext);           \
 133 } while (0)
 134
 135 #undef EASSERTF
 136 #define EASSERTF(expr, ext, fmt, args...) do {                          \
 137         if (!(expr)) {                                                  \
 138                 OSC_EXTENT_DUMP(D_ERROR, (ext), fmt, ##args);           \
 139                 osc_extent_tree_dump(D_ERROR, (ext)->oe_obj);           \
 140                 LASSERT(expr);                                          \
 141         }                                                               \
 142 } while (0)
 143
 144 #undef EASSERT
 145 #define EASSERT(expr, ext) EASSERTF(expr, ext, "\n")
 146
 147 static inline struct osc_extent *rb_extent(struct rb_node *n)
 148 {
 149         if (n == NULL)
 150                 return NULL;
 151
 152         return container_of(n, struct osc_extent, oe_node);
 153 }
 154
 155 static inline struct osc_extent *next_extent(struct osc_extent *ext)
 156 {
 157         if (ext == NULL)
 158                 return NULL;
 159
 160         LASSERT(ext->oe_intree);
 161         return rb_extent(rb_next(&ext->oe_node));
 162 }
 163
 164 static inline struct osc_extent *prev_extent(struct osc_extent *ext)
 165 {
 166         if (ext == NULL)
 167                 return NULL;
 168
 169         LASSERT(ext->oe_intree);
 170         return rb_extent(rb_prev(&ext->oe_node));
 171 }
 172
 173 static inline struct osc_extent *first_extent(struct osc_object *obj)
 174 {
 175         return rb_extent(rb_first(&obj->oo_root));
 176 }
 177
 178 /* object must be locked by caller. */
 179 static int osc_extent_sanity_check0(struct osc_extent *ext,
 180                                     const char *func, const int line)
 181 {
 182         struct osc_object *obj = ext->oe_obj;
 183         struct osc_async_page *oap;
 184         size_t page_count;
 185         int rc = 0;
 186
 187         if (!osc_object_is_locked(obj))
 188                 GOTO(out, rc = 9);
 189
 190         if (ext->oe_state >= OES_STATE_MAX)
 191                 GOTO(out, rc = 10);
 192
 193         if (atomic_read(&ext->oe_refc) <= 0)
 194                 GOTO(out, rc = 20);
 195
 196         if (atomic_read(&ext->oe_refc) < atomic_read(&ext->oe_users))
 197                 GOTO(out, rc = 30);
 198
 199         switch (ext->oe_state) {
 200         case OES_INV:
 201                 if (ext->oe_nr_pages > 0 || !list_empty(&ext->oe_pages))
 202                         GOTO(out, rc = 35);
 203                 GOTO(out, rc = 0);
 204                 break;
 205         case OES_ACTIVE:
 206                 if (atomic_read(&ext->oe_users) == 0)
 207                         GOTO(out, rc = 40);
 208                 if (ext->oe_hp)
 209                         GOTO(out, rc = 50);
 210                 if (ext->oe_fsync_wait && !ext->oe_urgent)
 211                         GOTO(out, rc = 55);
 212                 break;
 213         case OES_CACHE:
 214                 if (ext->oe_grants == 0)
 215                         GOTO(out, rc = 60);
 216                 if (ext->oe_fsync_wait && !ext->oe_urgent && !ext->oe_hp)
 217                         GOTO(out, rc = 65);
 218         default:
 219                 if (atomic_read(&ext->oe_users) > 0)
 220                         GOTO(out, rc = 70);
 221         }
 222
 223         if (ext->oe_max_end < ext->oe_end || ext->oe_end < ext->oe_start)
 224                 GOTO(out, rc = 80);
 225
 226         if (ext->oe_sync && ext->oe_grants > 0)
 227                 GOTO(out, rc = 90);
 228
 229         if (ext->oe_dlmlock != NULL &&
 230             ext->oe_dlmlock->l_resource->lr_type == LDLM_EXTENT &&
 231             !ldlm_is_failed(ext->oe_dlmlock)) {
 232                 struct ldlm_extent *extent;
 233
 234                 extent = &ext->oe_dlmlock->l_policy_data.l_extent;
 235                 if (!(extent->start <= cl_offset(osc2cl(obj), ext->oe_start) &&
 236                       extent->end   >= cl_offset(osc2cl(obj), ext->oe_max_end)))
 237                         GOTO(out, rc = 100);
 238
 239                 if (!(ext->oe_dlmlock->l_granted_mode & (LCK_PW | LCK_GROUP)))
 240                         GOTO(out, rc = 102);
 241         }
 242
 243         if (ext->oe_nr_pages > ext->oe_mppr)
 244                 GOTO(out, rc = 105);
 245
 246         /* Do not verify page list if extent is in RPC. This is because an
 247          * in-RPC extent is supposed to be exclusively accessible w/o lock. */
 248         if (ext->oe_state > OES_CACHE)
 249                 GOTO(out, rc = 0);
 250
 251         if (!extent_debug)
 252                 GOTO(out, rc = 0);
 253
 254         page_count = 0;
 255         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
 256                 pgoff_t index = osc_index(oap2osc(oap));
 257                 ++page_count;
 258                 if (index > ext->oe_end || index < ext->oe_start)
 259                         GOTO(out, rc = 110);
 260         }
 261         if (page_count != ext->oe_nr_pages)
 262                 GOTO(out, rc = 120);
 263
 264 out:
 265         if (rc != 0)
 266                 OSC_EXTENT_DUMP(D_ERROR, ext,
 267                                 "%s:%d sanity check %p failed with rc = %d\n",
 268                                 func, line, ext, rc);
 269         return rc;
 270 }
 271
 272 #define sanity_check_nolock(ext) \
 273         osc_extent_sanity_check0(ext, __func__, __LINE__)
 274
 275 #define sanity_check(ext) ({                                                   \
 276         int __res;                                                             \
 277         osc_object_lock((ext)->oe_obj);                                        \
 278         __res = sanity_check_nolock(ext);                                      \
 279         osc_object_unlock((ext)->oe_obj);                                      \
 280         __res;                                                                 \
 281 })
 282
 283
 284 /**
 285  * sanity check - to make sure there is no overlapped extent in the tree.
 286  */
 287 static int osc_extent_is_overlapped(struct osc_object *obj,
 288                                     struct osc_extent *ext)
 289 {
 290         struct osc_extent *tmp;
 291
 292         LASSERT(osc_object_is_locked(obj));
 293
 294         if (!extent_debug)
 295                 return 0;
 296
 297         for (tmp = first_extent(obj); tmp != NULL; tmp = next_extent(tmp)) {
 298                 if (tmp == ext)
 299                         continue;
 300                 if (tmp->oe_end >= ext->oe_start &&
 301                     tmp->oe_start <= ext->oe_end)
 302                         return 1;
 303         }
 304         return 0;
 305 }
 306
 307 static void osc_extent_state_set(struct osc_extent *ext, int state)
 308 {
 309         LASSERT(osc_object_is_locked(ext->oe_obj));
 310         LASSERT(state >= OES_INV && state < OES_STATE_MAX);
 311
 312         /* Never try to sanity check a state changing extent :-) */
 313         /* LASSERT(sanity_check_nolock(ext) == 0); */
 314
 315         /* TODO: validate the state machine */
 316         ext->oe_state = state;
 317         wake_up_all(&ext->oe_waitq);
 318 }
 319
 320 static struct osc_extent *osc_extent_alloc(struct osc_object *obj)
 321 {
 322         struct osc_extent *ext;
 323
 324         OBD_SLAB_ALLOC_PTR_GFP(ext, osc_extent_kmem, GFP_NOFS);
 325         if (ext == NULL)
 326                 return NULL;
 327
 328         RB_CLEAR_NODE(&ext->oe_node);
 329         ext->oe_obj = obj;
 330         cl_object_get(osc2cl(obj));
 331         atomic_set(&ext->oe_refc, 1);
 332         atomic_set(&ext->oe_users, 0);
 333         INIT_LIST_HEAD(&ext->oe_link);
 334         ext->oe_state = OES_INV;
 335         INIT_LIST_HEAD(&ext->oe_pages);
 336         init_waitqueue_head(&ext->oe_waitq);
 337         ext->oe_dlmlock = NULL;
 338
 339         return ext;
 340 }
 341
 342 static void osc_extent_free(struct osc_extent *ext)
 343 {
 344         OBD_SLAB_FREE_PTR(ext, osc_extent_kmem);
 345 }
 346
 347 static struct osc_extent *osc_extent_get(struct osc_extent *ext)
 348 {
 349         LASSERT(atomic_read(&ext->oe_refc) >= 0);
 350         atomic_inc(&ext->oe_refc);
 351         return ext;
 352 }
 353
 354 static void osc_extent_put(const struct lu_env *env, struct osc_extent *ext)
 355 {
 356         LASSERT(atomic_read(&ext->oe_refc) > 0);
 357         if (atomic_dec_and_test(&ext->oe_refc)) {
 358                 LASSERT(list_empty(&ext->oe_link));
 359                 LASSERT(atomic_read(&ext->oe_users) == 0);
 360                 LASSERT(ext->oe_state == OES_INV);
 361                 LASSERT(!ext->oe_intree);
 362
 363                 if (ext->oe_dlmlock != NULL) {
 364                         lu_ref_add(&ext->oe_dlmlock->l_reference,
 365                                    "osc_extent", ext);
 366                         LDLM_LOCK_PUT(ext->oe_dlmlock);
 367                         ext->oe_dlmlock = NULL;
 368                 }
 369                 cl_object_put(env, osc2cl(ext->oe_obj));
 370                 osc_extent_free(ext);
 371         }
 372 }
 373
 374 /**
 375  * osc_extent_put_trust() is a special version of osc_extent_put() when
 376  * it's known that the caller is not the last user. This is to address the
 377  * problem of lacking of lu_env ;-).
 378  */
 379 static void osc_extent_put_trust(struct osc_extent *ext)
 380 {
 381         LASSERT(atomic_read(&ext->oe_refc) > 1);
 382         LASSERT(osc_object_is_locked(ext->oe_obj));
 383         atomic_dec(&ext->oe_refc);
 384 }
 385
 386 /**
 387  * Return the extent which includes pgoff @index, or return the greatest
 388  * previous extent in the tree.
 389  */
 390 static struct osc_extent *osc_extent_search(struct osc_object *obj,
 391                                             pgoff_t index)
 392 {
 393         struct rb_node    *n = obj->oo_root.rb_node;
 394         struct osc_extent *tmp, *p = NULL;
 395
 396         LASSERT(osc_object_is_locked(obj));
 397         while (n != NULL) {
 398                 tmp = rb_extent(n);
 399                 if (index < tmp->oe_start) {
 400                         n = n->rb_left;
 401                 } else if (index > tmp->oe_end) {
 402                         p = rb_extent(n);
 403                         n = n->rb_right;
 404                 } else {
 405                         return tmp;
 406                 }
 407         }
 408         return p;
 409 }
 410
 411 /*
 412  * Return the extent covering @index, otherwise return NULL.
 413  * caller must have held object lock.
 414  */
 415 static struct osc_extent *osc_extent_lookup(struct osc_object *obj,
 416                                             pgoff_t index)
 417 {
 418         struct osc_extent *ext;
 419
 420         ext = osc_extent_search(obj, index);
 421         if (ext != NULL && ext->oe_start <= index && index <= ext->oe_end)
 422                 return osc_extent_get(ext);
 423         return NULL;
 424 }
 425
 426 /* caller must have held object lock. */
 427 static void osc_extent_insert(struct osc_object *obj, struct osc_extent *ext)
 428 {
 429         struct rb_node   **n      = &obj->oo_root.rb_node;
 430         struct rb_node    *parent = NULL;
 431         struct osc_extent *tmp;
 432
 433         LASSERT(ext->oe_intree == 0);
 434         LASSERT(ext->oe_obj == obj);
 435         LASSERT(osc_object_is_locked(obj));
 436         while (*n != NULL) {
 437                 tmp = rb_extent(*n);
 438                 parent = *n;
 439
 440                 if (ext->oe_end < tmp->oe_start)
 441                         n = &(*n)->rb_left;
 442                 else if (ext->oe_start > tmp->oe_end)
 443                         n = &(*n)->rb_right;
 444                 else
 445                         EASSERTF(0, tmp, EXTSTR"\n", EXTPARA(ext));
 446         }
 447         rb_link_node(&ext->oe_node, parent, n);
 448         rb_insert_color(&ext->oe_node, &obj->oo_root);
 449         osc_extent_get(ext);
 450         ext->oe_intree = 1;
 451 }
 452
 453 /* caller must have held object lock. */
 454 static void osc_extent_erase(struct osc_extent *ext)
 455 {
 456         struct osc_object *obj = ext->oe_obj;
 457         LASSERT(osc_object_is_locked(obj));
 458         if (ext->oe_intree) {
 459                 rb_erase(&ext->oe_node, &obj->oo_root);
 460                 ext->oe_intree = 0;
 461                 /* rbtree held a refcount */
 462                 osc_extent_put_trust(ext);
 463         }
 464 }
 465
 466 static struct osc_extent *osc_extent_hold(struct osc_extent *ext)
 467 {
 468         struct osc_object *obj = ext->oe_obj;
 469
 470         LASSERT(osc_object_is_locked(obj));
 471         LASSERT(ext->oe_state == OES_ACTIVE || ext->oe_state == OES_CACHE);
 472         if (ext->oe_state == OES_CACHE) {
 473                 osc_extent_state_set(ext, OES_ACTIVE);
 474                 osc_update_pending(obj, OBD_BRW_WRITE, -ext->oe_nr_pages);
 475         }
 476         atomic_inc(&ext->oe_users);
 477         list_del_init(&ext->oe_link);
 478         return osc_extent_get(ext);
 479 }
 480
 481 static void __osc_extent_remove(struct osc_extent *ext)
 482 {
 483         LASSERT(osc_object_is_locked(ext->oe_obj));
 484         LASSERT(list_empty(&ext->oe_pages));
 485         osc_extent_erase(ext);
 486         list_del_init(&ext->oe_link);
 487         osc_extent_state_set(ext, OES_INV);
 488         OSC_EXTENT_DUMP(D_CACHE, ext, "destroyed.\n");
 489 }
 490
 491 static void osc_extent_remove(struct osc_extent *ext)
 492 {
 493         struct osc_object *obj = ext->oe_obj;
 494
 495         osc_object_lock(obj);
 496         __osc_extent_remove(ext);
 497         osc_object_unlock(obj);
 498 }
 499
 500 /**
 501  * This function is used to merge extents to get better performance. It checks
 502  * if @cur and @victim are contiguous at block level.
 503  */
 504 static int osc_extent_merge(const struct lu_env *env, struct osc_extent *cur,
 505                             struct osc_extent *victim)
 506 {
 507         struct osc_object       *obj = cur->oe_obj;
 508         struct client_obd       *cli = osc_cli(obj);
 509         pgoff_t                  chunk_start;
 510         pgoff_t                  chunk_end;
 511         int                      ppc_bits;
 512
 513         LASSERT(cur->oe_state == OES_CACHE);
 514         LASSERT(osc_object_is_locked(obj));
 515         if (victim == NULL)
 516                 return -EINVAL;
 517
 518         if (victim->oe_state != OES_CACHE || victim->oe_fsync_wait)
 519                 return -EBUSY;
 520
 521         if (cur->oe_max_end != victim->oe_max_end)
 522                 return -ERANGE;
 523
 524         LASSERT(cur->oe_dlmlock == victim->oe_dlmlock);
 525         ppc_bits = osc_cli(obj)->cl_chunkbits - PAGE_SHIFT;
 526         chunk_start = cur->oe_start >> ppc_bits;
 527         chunk_end   = cur->oe_end   >> ppc_bits;
 528         if (chunk_start   != (victim->oe_end >> ppc_bits) + 1 &&
 529             chunk_end + 1 != victim->oe_start >> ppc_bits)
 530                 return -ERANGE;
 531
 532         /* overall extent size should not exceed the max supported limit
 533          * reported by the server */
 534         if (cur->oe_end - cur->oe_start + 1 +
 535             victim->oe_end - victim->oe_start + 1 > cli->cl_max_extent_pages)
 536                 return -ERANGE;
 537
 538         OSC_EXTENT_DUMP(D_CACHE, victim, "will be merged by %p.\n", cur);
 539
 540         cur->oe_start     = min(cur->oe_start, victim->oe_start);
 541         cur->oe_end       = max(cur->oe_end,   victim->oe_end);
 542         /* per-extent tax should be accounted only once for the whole extent */
 543         cur->oe_grants   += victim->oe_grants - cli->cl_grant_extent_tax;
 544         cur->oe_nr_pages += victim->oe_nr_pages;
 545         /* only the following bits are needed to merge */
 546         cur->oe_urgent   |= victim->oe_urgent;
 547         cur->oe_memalloc |= victim->oe_memalloc;
 548         list_splice_init(&victim->oe_pages, &cur->oe_pages);
 549         list_del_init(&victim->oe_link);
 550         victim->oe_nr_pages = 0;
 551
 552         osc_extent_get(victim);
 553         __osc_extent_remove(victim);
 554         osc_extent_put(env, victim);
 555
 556         OSC_EXTENT_DUMP(D_CACHE, cur, "after merging %p.\n", victim);
 557         return 0;
 558 }
 559
 560 /**
 561  * Drop user count of osc_extent, and unplug IO asynchronously.
 562  */
 563 int osc_extent_release(const struct lu_env *env, struct osc_extent *ext)
 564 {
 565         struct osc_object *obj = ext->oe_obj;
 566         struct client_obd *cli = osc_cli(obj);
 567         int rc = 0;
 568         ENTRY;
 569
 570         LASSERT(atomic_read(&ext->oe_users) > 0);
 571         LASSERT(sanity_check(ext) == 0);
 572         LASSERT(ext->oe_grants > 0);
 573
 574         if (atomic_dec_and_lock(&ext->oe_users, &obj->oo_lock)) {
 575                 LASSERT(ext->oe_state == OES_ACTIVE);
 576                 if (ext->oe_trunc_pending) {
 577                         /* a truncate process is waiting for this extent.
 578                          * This may happen due to a race, check
 579                          * osc_cache_truncate_start(). */
 580                         osc_extent_state_set(ext, OES_TRUNC);
 581                         ext->oe_trunc_pending = 0;
 582                 } else {
 583                         int grant = 0;
 584
 585                         osc_extent_state_set(ext, OES_CACHE);
 586                         osc_update_pending(obj, OBD_BRW_WRITE,
 587                                            ext->oe_nr_pages);
 588
 589                         /* try to merge the previous and next extent. */
 590                         if (osc_extent_merge(env, ext, prev_extent(ext)) == 0)
 591                                 grant += cli->cl_grant_extent_tax;
 592                         if (osc_extent_merge(env, ext, next_extent(ext)) == 0)
 593                                 grant += cli->cl_grant_extent_tax;
 594                         if (grant > 0)
 595                                 osc_unreserve_grant(cli, 0, grant);
 596
 597                         if (ext->oe_urgent)
 598                                 list_move_tail(&ext->oe_link,
 599                                                &obj->oo_urgent_exts);
 600                         else if (ext->oe_nr_pages == ext->oe_mppr) {
 601                                 list_move_tail(&ext->oe_link,
 602                                                &obj->oo_full_exts);
 603                         }
 604                 }
 605                 osc_object_unlock(obj);
 606
 607                 osc_io_unplug_async(env, cli, obj);
 608         }
 609         osc_extent_put(env, ext);
 610         RETURN(rc);
 611 }
 612
 613 static inline int overlapped(struct osc_extent *ex1, struct osc_extent *ex2)
 614 {
 615         return !(ex1->oe_end < ex2->oe_start || ex2->oe_end < ex1->oe_start);
 616 }
 617
 618 /**
 619  * Find or create an extent which includes @index, core function to manage
 620  * extent tree.
 621  */
 622 static struct osc_extent *osc_extent_find(const struct lu_env *env,
 623                                           struct osc_object *obj, pgoff_t index,
 624                                           unsigned int *grants)
 625 {
 626         struct client_obd *cli = osc_cli(obj);
 627         struct osc_lock   *olck;
 628         struct cl_lock_descr *descr;
 629         struct osc_extent *cur;
 630         struct osc_extent *ext;
 631         struct osc_extent *conflict = NULL;
 632         struct osc_extent *found = NULL;
 633         pgoff_t    chunk;
 634         pgoff_t    max_end;
 635         unsigned int max_pages; /* max_pages_per_rpc */
 636         unsigned int chunksize;
 637         int        ppc_bits; /* pages per chunk bits */
 638         pgoff_t    chunk_mask;
 639         int        rc;
 640         ENTRY;
 641
 642         cur = osc_extent_alloc(obj);
 643         if (cur == NULL)
 644                 RETURN(ERR_PTR(-ENOMEM));
 645
 646         olck = osc_env_io(env)->oi_write_osclock;
 647         LASSERTF(olck != NULL, "page %lu is not covered by lock\n", index);
 648         LASSERT(olck->ols_state == OLS_GRANTED);
 649
 650         descr = &olck->ols_cl.cls_lock->cll_descr;
 651         LASSERT(descr->cld_mode >= CLM_WRITE);
 652
 653         LASSERTF(cli->cl_chunkbits >= PAGE_SHIFT,
 654                  "chunkbits: %u\n", cli->cl_chunkbits);
 655         ppc_bits   = cli->cl_chunkbits - PAGE_SHIFT;
 656         chunk_mask = ~((1 << ppc_bits) - 1);
 657         chunksize  = 1 << cli->cl_chunkbits;
 658         chunk      = index >> ppc_bits;
 659
 660         /* align end to RPC edge. */
 661         max_pages = cli->cl_max_pages_per_rpc;
 662         if ((max_pages & ~chunk_mask) != 0) {
 663                 CERROR("max_pages: %#x chunkbits: %u chunk_mask: %#lx\n",
 664                        max_pages, cli->cl_chunkbits, chunk_mask);
 665                 RETURN(ERR_PTR(-EINVAL));
 666         }
 667         max_end = index - (index % max_pages) + max_pages - 1;
 668         max_end = min_t(pgoff_t, max_end, descr->cld_end);
 669
 670         /* initialize new extent by parameters so far */
 671         cur->oe_max_end = max_end;
 672         cur->oe_start   = index & chunk_mask;
 673         cur->oe_end     = ((index + ~chunk_mask + 1) & chunk_mask) - 1;
 674         if (cur->oe_start < descr->cld_start)
 675                 cur->oe_start = descr->cld_start;
 676         if (cur->oe_end > max_end)
 677                 cur->oe_end = max_end;
 678         cur->oe_grants  = 0;
 679         cur->oe_mppr    = max_pages;
 680         if (olck->ols_dlmlock != NULL) {
 681                 LASSERT(olck->ols_hold);
 682                 cur->oe_dlmlock = LDLM_LOCK_GET(olck->ols_dlmlock);
 683                 lu_ref_add(&olck->ols_dlmlock->l_reference, "osc_extent", cur);
 684         }
 685
 686         /* grants has been allocated by caller */
 687         LASSERTF(*grants >= chunksize + cli->cl_grant_extent_tax,
 688                  "%u/%u/%u.\n", *grants, chunksize, cli->cl_grant_extent_tax);
 689         LASSERTF((max_end - cur->oe_start) < max_pages, EXTSTR"\n",
 690                  EXTPARA(cur));
 691
 692 restart:
 693         osc_object_lock(obj);
 694         ext = osc_extent_search(obj, cur->oe_start);
 695         if (ext == NULL)
 696                 ext = first_extent(obj);
 697         while (ext != NULL) {
 698                 pgoff_t ext_chk_start = ext->oe_start >> ppc_bits;
 699                 pgoff_t ext_chk_end   = ext->oe_end   >> ppc_bits;
 700
 701                 LASSERT(sanity_check_nolock(ext) == 0);
 702                 if (chunk > ext_chk_end + 1)
 703                         break;
 704
 705                 /* if covering by different locks, no chance to match */
 706                 if (olck->ols_dlmlock != ext->oe_dlmlock) {
 707                         EASSERTF(!overlapped(ext, cur), ext,
 708                                  EXTSTR"\n", EXTPARA(cur));
 709
 710                         ext = next_extent(ext);
 711                         continue;
 712                 }
 713
 714                 /* discontiguous chunks? */
 715                 if (chunk + 1 < ext_chk_start) {
 716                         ext = next_extent(ext);
 717                         continue;
 718                 }
 719
 720                 /* ok, from now on, ext and cur have these attrs:
 721                  * 1. covered by the same lock
 722                  * 2. contiguous at chunk level or overlapping. */
 723
 724                 if (overlapped(ext, cur)) {
 725                         /* cur is the minimum unit, so overlapping means
 726                          * full contain. */
 727                         EASSERTF((ext->oe_start <= cur->oe_start &&
 728                                   ext->oe_end >= cur->oe_end),
 729                                  ext, EXTSTR"\n", EXTPARA(cur));
 730
 731                         if (ext->oe_state > OES_CACHE || ext->oe_fsync_wait) {
 732                                 /* for simplicity, we wait for this extent to
 733                                  * finish before going forward. */
 734                                 conflict = osc_extent_get(ext);
 735                                 break;
 736                         }
 737
 738                         found = osc_extent_hold(ext);
 739                         break;
 740                 }
 741
 742                 /* non-overlapped extent */
 743                 if (ext->oe_state != OES_CACHE || ext->oe_fsync_wait) {
 744                         /* we can't do anything for a non OES_CACHE extent, or
 745                          * if there is someone waiting for this extent to be
 746                          * flushed, try next one. */
 747                         ext = next_extent(ext);
 748                         continue;
 749                 }
 750
 751                 /* check if they belong to the same rpc slot before trying to
 752                  * merge. the extents are not overlapped and contiguous at
 753                  * chunk level to get here. */
 754                 if (ext->oe_max_end != max_end) {
 755                         /* if they don't belong to the same RPC slot or
 756                          * max_pages_per_rpc has ever changed, do not merge. */
 757                         ext = next_extent(ext);
 758                         continue;
 759                 }
 760
 761                 /* check whether maximum extent size will be hit */
 762                 if ((ext_chk_end - ext_chk_start + 1 + 1) << ppc_bits >
 763                     cli->cl_max_extent_pages) {
 764                         ext = next_extent(ext);
 765                         continue;
 766                 }
 767
 768                 /* it's required that an extent must be contiguous at chunk
 769                  * level so that we know the whole extent is covered by grant
 770                  * (the pages in the extent are NOT required to be contiguous).
 771                  * Otherwise, it will be too much difficult to know which
 772                  * chunks have grants allocated. */
 773
 774                 /* try to do front merge - extend ext's start */
 775                 if (chunk + 1 == ext_chk_start) {
 776                         /* ext must be chunk size aligned */
 777                         EASSERT((ext->oe_start & ~chunk_mask) == 0, ext);
 778
 779                         /* pull ext's start back to cover cur */
 780                         ext->oe_start   = cur->oe_start;
 781                         ext->oe_grants += chunksize;
 782                         LASSERT(*grants >= chunksize);
 783                         *grants -= chunksize;
 784
 785                         found = osc_extent_hold(ext);
 786                 } else if (chunk == ext_chk_end + 1) {
 787                         /* rear merge */
 788                         ext->oe_end     = cur->oe_end;
 789                         ext->oe_grants += chunksize;
 790                         LASSERT(*grants >= chunksize);
 791                         *grants -= chunksize;
 792
 793                         /* try to merge with the next one because we just fill
 794                          * in a gap */
 795                         if (osc_extent_merge(env, ext, next_extent(ext)) == 0)
 796                                 /* we can save extent tax from next extent */
 797                                 *grants += cli->cl_grant_extent_tax;
 798
 799                         found = osc_extent_hold(ext);
 800                 }
 801                 if (found != NULL)
 802                         break;
 803
 804                 ext = next_extent(ext);
 805         }
 806
 807         osc_extent_tree_dump(D_CACHE, obj);
 808         if (found != NULL) {
 809                 LASSERT(conflict == NULL);
 810                 if (!IS_ERR(found)) {
 811                         LASSERT(found->oe_dlmlock == cur->oe_dlmlock);
 812                         OSC_EXTENT_DUMP(D_CACHE, found,
 813                                         "found caching ext for %lu.\n", index);
 814                 }
 815         } else if (conflict == NULL) {
 816                 /* create a new extent */
 817                 EASSERT(osc_extent_is_overlapped(obj, cur) == 0, cur);
 818                 cur->oe_grants = chunksize + cli->cl_grant_extent_tax;
 819                 LASSERT(*grants >= cur->oe_grants);
 820                 *grants -= cur->oe_grants;
 821
 822                 cur->oe_state = OES_CACHE;
 823                 found = osc_extent_hold(cur);
 824                 osc_extent_insert(obj, cur);
 825                 OSC_EXTENT_DUMP(D_CACHE, cur, "add into tree %lu/%lu.\n",
 826                                 index, descr->cld_end);
 827         }
 828         osc_object_unlock(obj);
 829
 830         if (conflict != NULL) {
 831                 LASSERT(found == NULL);
 832
 833                 /* waiting for IO to finish. Please notice that it's impossible
 834                  * to be an OES_TRUNC extent. */
 835                 rc = osc_extent_wait(env, conflict, OES_INV);
 836                 osc_extent_put(env, conflict);
 837                 conflict = NULL;
 838                 if (rc < 0)
 839                         GOTO(out, found = ERR_PTR(rc));
 840
 841                 goto restart;
 842         }
 843         EXIT;
 844
 845 out:
 846         osc_extent_put(env, cur);
 847         return found;
 848 }
 849
 850 /**
 851  * Called when IO is finished to an extent.
 852  */
 853 int osc_extent_finish(const struct lu_env *env, struct osc_extent *ext,
 854                       int sent, int rc)
 855 {
 856         struct client_obd *cli = osc_cli(ext->oe_obj);
 857         struct osc_async_page *oap;
 858         struct osc_async_page *tmp;
 859         int nr_pages = ext->oe_nr_pages;
 860         int lost_grant = 0;
 861         int blocksize = cli->cl_import->imp_obd->obd_osfs.os_bsize ? : 4096;
 862         loff_t last_off = 0;
 863         int last_count = -1;
 864         ENTRY;
 865
 866         OSC_EXTENT_DUMP(D_CACHE, ext, "extent finished.\n");
 867
 868         ext->oe_rc = rc ?: ext->oe_nr_pages;
 869         EASSERT(ergo(rc == 0, ext->oe_state == OES_RPC), ext);
 870
 871         osc_lru_add_batch(cli, &ext->oe_pages);
 872         list_for_each_entry_safe(oap, tmp, &ext->oe_pages,
 873                                      oap_pending_item) {
 874                 list_del_init(&oap->oap_rpc_item);
 875                 list_del_init(&oap->oap_pending_item);
 876                 if (last_off <= oap->oap_obj_off) {
 877                         last_off = oap->oap_obj_off;
 878                         last_count = oap->oap_count;
 879                 }
 880
 881                 --ext->oe_nr_pages;
 882                 osc_ap_completion(env, cli, oap, sent, rc);
 883         }
 884         EASSERT(ext->oe_nr_pages == 0, ext);
 885
 886         if (!sent) {
 887                 lost_grant = ext->oe_grants;
 888         } else if (blocksize < PAGE_SIZE &&
 889                    last_count != PAGE_SIZE) {
 890                 /* For short writes we shouldn't count parts of pages that
 891                  * span a whole chunk on the OST side, or our accounting goes
 892                  * wrong.  Should match the code in filter_grant_check. */
 893                 int offset = last_off & ~PAGE_MASK;
 894                 int count = last_count + (offset & (blocksize - 1));
 895                 int end = (offset + last_count) & (blocksize - 1);
 896                 if (end)
 897                         count += blocksize - end;
 898
 899                 lost_grant = PAGE_SIZE - count;
 900         }
 901         if (ext->oe_grants > 0)
 902                 osc_free_grant(cli, nr_pages, lost_grant, ext->oe_grants);
 903
 904         osc_extent_remove(ext);
 905         /* put the refcount for RPC */
 906         osc_extent_put(env, ext);
 907         RETURN(0);
 908 }
 909
 910 static int extent_wait_cb(struct osc_extent *ext, enum osc_extent_state state)
 911 {
 912         int ret;
 913
 914         osc_object_lock(ext->oe_obj);
 915         ret = ext->oe_state == state;
 916         osc_object_unlock(ext->oe_obj);
 917
 918         return ret;
 919 }
 920
 921 /**
 922  * Wait for the extent's state to become @state.
 923  */
 924 static int osc_extent_wait(const struct lu_env *env, struct osc_extent *ext,
 925                            enum osc_extent_state state)
 926 {
 927         struct osc_object *obj = ext->oe_obj;
 928         struct l_wait_info lwi = LWI_TIMEOUT_INTR(cfs_time_seconds(600), NULL,
 929                                                   LWI_ON_SIGNAL_NOOP, NULL);
 930         int rc = 0;
 931         ENTRY;
 932
 933         osc_object_lock(obj);
 934         LASSERT(sanity_check_nolock(ext) == 0);
 935         /* `Kick' this extent only if the caller is waiting for it to be
 936          * written out. */
 937         if (state == OES_INV && !ext->oe_urgent && !ext->oe_hp) {
 938                 if (ext->oe_state == OES_ACTIVE) {
 939                         ext->oe_urgent = 1;
 940                 } else if (ext->oe_state == OES_CACHE) {
 941                         ext->oe_urgent = 1;
 942                         osc_extent_hold(ext);
 943                         rc = 1;
 944                 }
 945         }
 946         osc_object_unlock(obj);
 947         if (rc == 1)
 948                 osc_extent_release(env, ext);
 949
 950         /* wait for the extent until its state becomes @state */
 951         rc = l_wait_event(ext->oe_waitq, extent_wait_cb(ext, state), &lwi);
 952         if (rc == -ETIMEDOUT) {
 953                 OSC_EXTENT_DUMP(D_ERROR, ext,
 954                         "%s: wait ext to %u timedout, recovery in progress?\n",
 955                         cli_name(osc_cli(obj)), state);
 956
 957                 lwi = LWI_INTR(NULL, NULL);
 958                 rc = l_wait_event(ext->oe_waitq, extent_wait_cb(ext, state),
 959                                   &lwi);
 960         }
 961         if (rc == 0 && ext->oe_rc < 0)
 962                 rc = ext->oe_rc;
 963         RETURN(rc);
 964 }
 965
 966 /**
 967  * Discard pages with index greater than @size. If @ext is overlapped with
 968  * @size, then partial truncate happens.
 969  */
 970 static int osc_extent_truncate(struct osc_extent *ext, pgoff_t trunc_index,
 971                                 bool partial)
 972 {
 973         struct lu_env         *env;
 974         struct cl_io          *io;
 975         struct osc_object     *obj = ext->oe_obj;
 976         struct client_obd     *cli = osc_cli(obj);
 977         struct osc_async_page *oap;
 978         struct osc_async_page *tmp;
 979         int                    pages_in_chunk = 0;
 980         int                    ppc_bits    = cli->cl_chunkbits -
 981                                              PAGE_SHIFT;
 982         __u64                  trunc_chunk = trunc_index >> ppc_bits;
 983         int                    grants   = 0;
 984         int                    nr_pages = 0;
 985         int                    rc       = 0;
 986         __u16                  refcheck;
 987         ENTRY;
 988
 989         LASSERT(sanity_check(ext) == 0);
 990         LASSERT(ext->oe_state == OES_TRUNC);
 991         LASSERT(!ext->oe_urgent);
 992
 993         /* Request new lu_env.
 994          * We can't use that env from osc_cache_truncate_start() because
 995          * it's from lov_io_sub and not fully initialized. */
 996         env = cl_env_get(&refcheck);
 997         if (IS_ERR(env))
 998                 RETURN(PTR_ERR(env));
 999
1000         io  = osc_env_thread_io(env);
1001         io->ci_obj = cl_object_top(osc2cl(obj));
1002         io->ci_ignore_layout = 1;
1003         rc = cl_io_init(env, io, CIT_MISC, io->ci_obj);
1004         if (rc < 0)
1005                 GOTO(out, rc);
1006
1007         /* discard all pages with index greater than trunc_index */
1008         list_for_each_entry_safe(oap, tmp, &ext->oe_pages,
1009                                      oap_pending_item) {
1010                 pgoff_t index = osc_index(oap2osc(oap));
1011                 struct cl_page  *page = oap2cl_page(oap);
1012
1013                 LASSERT(list_empty(&oap->oap_rpc_item));
1014
1015                 /* only discard the pages with their index greater than
1016                  * trunc_index, and ... */
1017                 if (index < trunc_index ||
1018                     (index == trunc_index && partial)) {
1019                         /* accounting how many pages remaining in the chunk
1020                          * so that we can calculate grants correctly. */
1021                         if (index >> ppc_bits == trunc_chunk)
1022                                 ++pages_in_chunk;
1023                         continue;
1024                 }
1025
1026                 list_del_init(&oap->oap_pending_item);
1027
1028                 cl_page_get(page);
1029                 lu_ref_add(&page->cp_reference, "truncate", current);
1030
1031                 if (cl_page_own(env, io, page) == 0) {
1032                         cl_page_discard(env, io, page);
1033                         cl_page_disown(env, io, page);
1034                 } else {
1035                         LASSERT(page->cp_state == CPS_FREEING);
1036                         LASSERT(0);
1037                 }
1038
1039                 lu_ref_del(&page->cp_reference, "truncate", current);
1040                 cl_page_put(env, page);
1041
1042                 --ext->oe_nr_pages;
1043                 ++nr_pages;
1044         }
1045         EASSERTF(ergo(ext->oe_start >= trunc_index + !!partial,
1046                       ext->oe_nr_pages == 0),
1047                 ext, "trunc_index %lu, partial %d\n", trunc_index, partial);
1048
1049         osc_object_lock(obj);
1050         if (ext->oe_nr_pages == 0) {
1051                 LASSERT(pages_in_chunk == 0);
1052                 grants = ext->oe_grants;
1053                 ext->oe_grants = 0;
1054         } else { /* calculate how many grants we can free */
1055                 int     chunks = (ext->oe_end >> ppc_bits) - trunc_chunk;
1056                 pgoff_t last_index;
1057
1058
1059                 /* if there is no pages in this chunk, we can also free grants
1060                  * for the last chunk */
1061                 if (pages_in_chunk == 0) {
1062                         /* if this is the 1st chunk and no pages in this chunk,
1063                          * ext->oe_nr_pages must be zero, so we should be in
1064                          * the other if-clause. */
1065                         LASSERT(trunc_chunk > 0);
1066                         --trunc_chunk;
1067                         ++chunks;
1068                 }
1069
1070                 /* this is what we can free from this extent */
1071                 grants          = chunks << cli->cl_chunkbits;
1072                 ext->oe_grants -= grants;
1073                 last_index      = ((trunc_chunk + 1) << ppc_bits) - 1;
1074                 ext->oe_end     = min(last_index, ext->oe_max_end);
1075                 LASSERT(ext->oe_end >= ext->oe_start);
1076                 LASSERT(ext->oe_grants > 0);
1077         }
1078         osc_object_unlock(obj);
1079
1080         if (grants > 0 || nr_pages > 0)
1081                 osc_free_grant(cli, nr_pages, grants, grants);
1082
1083 out:
1084         cl_io_fini(env, io);
1085         cl_env_put(env, &refcheck);
1086         RETURN(rc);
1087 }
1088
1089 /**
1090  * This function is used to make the extent prepared for transfer.
1091  * A race with flusing page - ll_writepage() has to be handled cautiously.
1092  */
1093 static int osc_extent_make_ready(const struct lu_env *env,
1094                                  struct osc_extent *ext)
1095 {
1096         struct osc_async_page *oap;
1097         struct osc_async_page *last = NULL;
1098         struct osc_object *obj = ext->oe_obj;
1099         unsigned int page_count = 0;
1100         int rc;
1101         ENTRY;
1102
1103         /* we're going to grab page lock, so object lock must not be taken. */
1104         LASSERT(sanity_check(ext) == 0);
1105         /* in locking state, any process should not touch this extent. */
1106         EASSERT(ext->oe_state == OES_LOCKING, ext);
1107         EASSERT(ext->oe_owner != NULL, ext);
1108
1109         OSC_EXTENT_DUMP(D_CACHE, ext, "make ready\n");
1110
1111         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
1112                 ++page_count;
1113                 if (last == NULL || last->oap_obj_off < oap->oap_obj_off)
1114                         last = oap;
1115
1116                 /* checking ASYNC_READY is race safe */
1117                 if ((oap->oap_async_flags & ASYNC_READY) != 0)
1118                         continue;
1119
1120                 rc = osc_make_ready(env, oap, OBD_BRW_WRITE);
1121                 switch (rc) {
1122                 case 0:
1123                         spin_lock(&oap->oap_lock);
1124                         oap->oap_async_flags |= ASYNC_READY;
1125                         spin_unlock(&oap->oap_lock);
1126                         break;
1127                 case -EALREADY:
1128                         LASSERT((oap->oap_async_flags & ASYNC_READY) != 0);
1129                         break;
1130                 default:
1131                         LASSERTF(0, "unknown return code: %d\n", rc);
1132                 }
1133         }
1134
1135         LASSERT(page_count == ext->oe_nr_pages);
1136         LASSERT(last != NULL);
1137         /* the last page is the only one we need to refresh its count by
1138          * the size of file. */
1139         if (!(last->oap_async_flags & ASYNC_COUNT_STABLE)) {
1140                 int last_oap_count = osc_refresh_count(env, last, OBD_BRW_WRITE);
1141                 LASSERT(last_oap_count > 0);
1142                 LASSERT(last->oap_page_off + last_oap_count <= PAGE_SIZE);
1143                 last->oap_count = last_oap_count;
1144                 spin_lock(&last->oap_lock);
1145                 last->oap_async_flags |= ASYNC_COUNT_STABLE;
1146                 spin_unlock(&last->oap_lock);
1147         }
1148
1149         /* for the rest of pages, we don't need to call osf_refresh_count()
1150          * because it's known they are not the last page */
1151         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
1152                 if (!(oap->oap_async_flags & ASYNC_COUNT_STABLE)) {
1153                         oap->oap_count = PAGE_SIZE - oap->oap_page_off;
1154                         spin_lock(&oap->oap_lock);
1155                         oap->oap_async_flags |= ASYNC_COUNT_STABLE;
1156                         spin_unlock(&oap->oap_lock);
1157                 }
1158         }
1159
1160         osc_object_lock(obj);
1161         osc_extent_state_set(ext, OES_RPC);
1162         osc_object_unlock(obj);
1163         /* get a refcount for RPC. */
1164         osc_extent_get(ext);
1165
1166         RETURN(0);
1167 }
1168
1169 /**
1170  * Quick and simple version of osc_extent_find(). This function is frequently
1171  * called to expand the extent for the same IO. To expand the extent, the
1172  * page index must be in the same or next chunk of ext->oe_end.
1173  */
1174 static int osc_extent_expand(struct osc_extent *ext, pgoff_t index,
1175                              unsigned int *grants)
1176 {
1177         struct osc_object *obj = ext->oe_obj;
1178         struct client_obd *cli = osc_cli(obj);
1179         struct osc_extent *next;
1180         int ppc_bits = cli->cl_chunkbits - PAGE_SHIFT;
1181         pgoff_t chunk = index >> ppc_bits;
1182         pgoff_t end_chunk;
1183         pgoff_t end_index;
1184         unsigned int chunksize = 1 << cli->cl_chunkbits;
1185         int rc = 0;
1186         ENTRY;
1187
1188         LASSERT(ext->oe_max_end >= index && ext->oe_start <= index);
1189         osc_object_lock(obj);
1190         LASSERT(sanity_check_nolock(ext) == 0);
1191         end_chunk = ext->oe_end >> ppc_bits;
1192         if (chunk > end_chunk + 1)
1193                 GOTO(out, rc = -ERANGE);
1194
1195         if (end_chunk >= chunk)
1196                 GOTO(out, rc = 0);
1197
1198         LASSERT(end_chunk + 1 == chunk);
1199
1200         /* try to expand this extent to cover @index */
1201         end_index = min(ext->oe_max_end, ((chunk + 1) << ppc_bits) - 1);
1202
1203         /* don't go over the maximum extent size reported by server */
1204         if (end_index - ext->oe_start + 1 > cli->cl_max_extent_pages)
1205                 GOTO(out, rc = -ERANGE);
1206
1207         next = next_extent(ext);
1208         if (next != NULL && next->oe_start <= end_index)
1209                 /* complex mode - overlapped with the next extent,
1210                  * this case will be handled by osc_extent_find() */
1211                 GOTO(out, rc = -EAGAIN);
1212
1213         ext->oe_end = end_index;
1214         ext->oe_grants += chunksize;
1215         LASSERT(*grants >= chunksize);
1216         *grants -= chunksize;
1217         EASSERTF(osc_extent_is_overlapped(obj, ext) == 0, ext,
1218                  "overlapped after expanding for %lu.\n", index);
1219         EXIT;
1220
1221 out:
1222         osc_object_unlock(obj);
1223         RETURN(rc);
1224 }
1225
1226 static void osc_extent_tree_dump0(int level, struct osc_object *obj,
1227                                   const char *func, int line)
1228 {
1229         struct osc_extent *ext;
1230         int cnt;
1231
1232         if (!cfs_cdebug_show(level, DEBUG_SUBSYSTEM))
1233                 return;
1234
1235         CDEBUG(level, "Dump object %p extents at %s:%d, mppr: %u.\n",
1236                obj, func, line, osc_cli(obj)->cl_max_pages_per_rpc);
1237
1238         /* osc_object_lock(obj); */
1239         cnt = 1;
1240         for (ext = first_extent(obj); ext != NULL; ext = next_extent(ext))
1241                 OSC_EXTENT_DUMP(level, ext, "in tree %d.\n", cnt++);
1242
1243         cnt = 1;
1244         list_for_each_entry(ext, &obj->oo_hp_exts, oe_link)
1245                 OSC_EXTENT_DUMP(level, ext, "hp %d.\n", cnt++);
1246
1247         cnt = 1;
1248         list_for_each_entry(ext, &obj->oo_urgent_exts, oe_link)
1249                 OSC_EXTENT_DUMP(level, ext, "urgent %d.\n", cnt++);
1250
1251         cnt = 1;
1252         list_for_each_entry(ext, &obj->oo_reading_exts, oe_link)
1253                 OSC_EXTENT_DUMP(level, ext, "reading %d.\n", cnt++);
1254         /* osc_object_unlock(obj); */
1255 }
1256
1257 /* ------------------ osc extent end ------------------ */
1258
1259 static inline int osc_is_ready(struct osc_object *osc)
1260 {
1261         return !list_empty(&osc->oo_ready_item) ||
1262                !list_empty(&osc->oo_hp_ready_item);
1263 }
1264
1265 #define OSC_IO_DEBUG(OSC, STR, args...)                                        \
1266         CDEBUG(D_CACHE, "obj %p ready %d|%c|%c wr %d|%c|%c rd %d|%c " STR,     \
1267                (OSC), osc_is_ready(OSC),                                       \
1268                list_empty_marker(&(OSC)->oo_hp_ready_item),                    \
1269                list_empty_marker(&(OSC)->oo_ready_item),                       \
1270                atomic_read(&(OSC)->oo_nr_writes),                              \
1271                list_empty_marker(&(OSC)->oo_hp_exts),                          \
1272                list_empty_marker(&(OSC)->oo_urgent_exts),                      \
1273                atomic_read(&(OSC)->oo_nr_reads),                               \
1274                list_empty_marker(&(OSC)->oo_reading_exts),                     \
1275                ##args)
1276
1277 static int osc_make_ready(const struct lu_env *env, struct osc_async_page *oap,
1278                           int cmd)
1279 {
1280         struct osc_page *opg  = oap2osc_page(oap);
1281         struct cl_page  *page = oap2cl_page(oap);
1282         int result;
1283
1284         LASSERT(cmd == OBD_BRW_WRITE); /* no cached reads */
1285
1286         ENTRY;
1287         result = cl_page_make_ready(env, page, CRT_WRITE);
1288         if (result == 0)
1289                 opg->ops_submit_time = cfs_time_current();
1290         RETURN(result);
1291 }
1292
1293 static int osc_refresh_count(const struct lu_env *env,
1294                              struct osc_async_page *oap, int cmd)
1295 {
1296         struct osc_page  *opg = oap2osc_page(oap);
1297         pgoff_t index = osc_index(oap2osc(oap));
1298         struct cl_object *obj;
1299         struct cl_attr   *attr = &osc_env_info(env)->oti_attr;
1300         int result;
1301         loff_t kms;
1302
1303         /* readpage queues with _COUNT_STABLE, shouldn't get here. */
1304         LASSERT(!(cmd & OBD_BRW_READ));
1305         LASSERT(opg != NULL);
1306         obj = opg->ops_cl.cpl_obj;
1307
1308         cl_object_attr_lock(obj);
1309         result = cl_object_attr_get(env, obj, attr);
1310         cl_object_attr_unlock(obj);
1311         if (result < 0)
1312                 return result;
1313         kms = attr->cat_kms;
1314         if (cl_offset(obj, index) >= kms)
1315                 /* catch race with truncate */
1316                 return 0;
1317         else if (cl_offset(obj, index + 1) > kms)
1318                 /* catch sub-page write at end of file */
1319                 return kms % PAGE_SIZE;
1320         else
1321                 return PAGE_SIZE;
1322 }
1323
1324 static int osc_completion(const struct lu_env *env, struct osc_async_page *oap,
1325                           int cmd, int rc)
1326 {
1327         struct osc_page   *opg  = oap2osc_page(oap);
1328         struct cl_page    *page = oap2cl_page(oap);
1329         enum cl_req_type   crt;
1330         int srvlock;
1331
1332         ENTRY;
1333
1334         cmd &= ~OBD_BRW_NOQUOTA;
1335         LASSERTF(equi(page->cp_state == CPS_PAGEIN,  cmd == OBD_BRW_READ),
1336                  "cp_state:%u, cmd:%d\n", page->cp_state, cmd);
1337         LASSERTF(equi(page->cp_state == CPS_PAGEOUT, cmd == OBD_BRW_WRITE),
1338                 "cp_state:%u, cmd:%d\n", page->cp_state, cmd);
1339         LASSERT(opg->ops_transfer_pinned);
1340
1341         crt = cmd == OBD_BRW_READ ? CRT_READ : CRT_WRITE;
1342         /* Clear opg->ops_transfer_pinned before VM lock is released. */
1343         opg->ops_transfer_pinned = 0;
1344
1345         opg->ops_submit_time = 0;
1346         srvlock = oap->oap_brw_flags & OBD_BRW_SRVLOCK;
1347
1348         /* statistic */
1349         if (rc == 0 && srvlock) {
1350                 struct lu_device *ld    = opg->ops_cl.cpl_obj->co_lu.lo_dev;
1351                 struct osc_stats *stats = &lu2osc_dev(ld)->od_stats;
1352                 size_t bytes = oap->oap_count;
1353
1354                 if (crt == CRT_READ)
1355                         stats->os_lockless_reads += bytes;
1356                 else
1357                         stats->os_lockless_writes += bytes;
1358         }
1359
1360         /*
1361          * This has to be the last operation with the page, as locks are
1362          * released in cl_page_completion() and nothing except for the
1363          * reference counter protects page from concurrent reclaim.
1364          */
1365         lu_ref_del(&page->cp_reference, "transfer", page);
1366
1367         cl_page_completion(env, page, crt, rc);
1368         cl_page_put(env, page);
1369
1370         RETURN(0);
1371 }
1372
1373 #define OSC_DUMP_GRANT(lvl, cli, fmt, args...) do {                     \
1374         struct client_obd *__tmp = (cli);                               \
1375         CDEBUG(lvl, "%s: grant { dirty: %ld/%ld dirty_pages: %ld/%lu "  \
1376                "dropped: %ld avail: %ld, dirty_grant: %ld, "            \
1377                "reserved: %ld, flight: %d } lru {in list: %ld, "        \
1378                "left: %ld, waiters: %d }" fmt "\n",                     \
1379                cli_name(__tmp),                                         \
1380                __tmp->cl_dirty_pages, __tmp->cl_dirty_max_pages,        \
1381                atomic_long_read(&obd_dirty_pages), obd_max_dirty_pages, \
1382                __tmp->cl_lost_grant, __tmp->cl_avail_grant,             \
1383                __tmp->cl_dirty_grant,                                   \
1384                __tmp->cl_reserved_grant, __tmp->cl_w_in_flight,         \
1385                atomic_long_read(&__tmp->cl_lru_in_list),                \
1386                atomic_long_read(&__tmp->cl_lru_busy),                   \
1387                atomic_read(&__tmp->cl_lru_shrinkers), ##args);          \
1388 } while (0)
1389
1390 /* caller must hold loi_list_lock */
1391 static void osc_consume_write_grant(struct client_obd *cli,
1392                                     struct brw_page *pga)
1393 {
1394         assert_spin_locked(&cli->cl_loi_list_lock);
1395         LASSERT(!(pga->flag & OBD_BRW_FROM_GRANT));
1396         atomic_long_inc(&obd_dirty_pages);
1397         cli->cl_dirty_pages++;
1398         pga->flag |= OBD_BRW_FROM_GRANT;
1399         CDEBUG(D_CACHE, "using %lu grant credits for brw %p page %p\n",
1400                PAGE_SIZE, pga, pga->pg);
1401         osc_update_next_shrink(cli);
1402 }
1403
1404 /* the companion to osc_consume_write_grant, called when a brw has completed.
1405  * must be called with the loi lock held. */
1406 static void osc_release_write_grant(struct client_obd *cli,
1407                                     struct brw_page *pga)
1408 {
1409         ENTRY;
1410
1411         assert_spin_locked(&cli->cl_loi_list_lock);
1412         if (!(pga->flag & OBD_BRW_FROM_GRANT)) {
1413                 EXIT;
1414                 return;
1415         }
1416
1417         pga->flag &= ~OBD_BRW_FROM_GRANT;
1418         atomic_long_dec(&obd_dirty_pages);
1419         cli->cl_dirty_pages--;
1420         if (pga->flag & OBD_BRW_NOCACHE) {
1421                 pga->flag &= ~OBD_BRW_NOCACHE;
1422                 atomic_long_dec(&obd_dirty_transit_pages);
1423                 cli->cl_dirty_transit--;
1424         }
1425         EXIT;
1426 }
1427
1428 /**
1429  * To avoid sleeping with object lock held, it's good for us allocate enough
1430  * grants before entering into critical section.
1431  *
1432  * client_obd_list_lock held by caller
1433  */
1434 static int osc_reserve_grant(struct client_obd *cli, unsigned int bytes)
1435 {
1436         int rc = -EDQUOT;
1437
1438         if (cli->cl_avail_grant >= bytes) {
1439                 cli->cl_avail_grant    -= bytes;
1440                 cli->cl_reserved_grant += bytes;
1441                 rc = 0;
1442         }
1443         return rc;
1444 }
1445
1446 static void __osc_unreserve_grant(struct client_obd *cli,
1447                                   unsigned int reserved, unsigned int unused)
1448 {
1449         /* it's quite normal for us to get more grant than reserved.
1450          * Thinking about a case that two extents merged by adding a new
1451          * chunk, we can save one extent tax. If extent tax is greater than
1452          * one chunk, we can save more grant by adding a new chunk */
1453         cli->cl_reserved_grant -= reserved;
1454         if (unused > reserved) {
1455                 cli->cl_avail_grant += reserved;
1456                 cli->cl_lost_grant  += unused - reserved;
1457                 cli->cl_dirty_grant -= unused - reserved;
1458         } else {
1459                 cli->cl_avail_grant += unused;
1460                 cli->cl_dirty_grant += reserved - unused;
1461         }
1462 }
1463
1464 static void osc_unreserve_grant(struct client_obd *cli,
1465                                 unsigned int reserved, unsigned int unused)
1466 {
1467         spin_lock(&cli->cl_loi_list_lock);
1468         __osc_unreserve_grant(cli, reserved, unused);
1469         if (unused > 0)
1470                 osc_wake_cache_waiters(cli);
1471         spin_unlock(&cli->cl_loi_list_lock);
1472 }
1473
1474 /**
1475  * Free grant after IO is finished or canceled.
1476  *
1477  * @lost_grant is used to remember how many grants we have allocated but not
1478  * used, we should return these grants to OST. There're two cases where grants
1479  * can be lost:
1480  * 1. truncate;
1481  * 2. blocksize at OST is less than PAGE_SIZE and a partial page was
1482  *    written. In this case OST may use less chunks to serve this partial
1483  *    write. OSTs don't actually know the page size on the client side. so
1484  *    clients have to calculate lost grant by the blocksize on the OST.
1485  *    See filter_grant_check() for details.
1486  */
1487 static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
1488                            unsigned int lost_grant, unsigned int dirty_grant)
1489 {
1490         unsigned long grant;
1491
1492         grant = (1 << cli->cl_chunkbits) + cli->cl_grant_extent_tax;
1493
1494         spin_lock(&cli->cl_loi_list_lock);
1495         atomic_long_sub(nr_pages, &obd_dirty_pages);
1496         cli->cl_dirty_pages -= nr_pages;
1497         cli->cl_lost_grant += lost_grant;
1498         cli->cl_dirty_grant -= dirty_grant;
1499         if (cli->cl_avail_grant < grant && cli->cl_lost_grant >= grant) {
1500                 /* borrow some grant from truncate to avoid the case that
1501                  * truncate uses up all avail grant */
1502                 cli->cl_lost_grant -= grant;
1503                 cli->cl_avail_grant += grant;
1504         }
1505         osc_wake_cache_waiters(cli);
1506         spin_unlock(&cli->cl_loi_list_lock);
1507         CDEBUG(D_CACHE, "lost %u grant: %lu avail: %lu dirty: %lu/%lu\n",
1508                lost_grant, cli->cl_lost_grant,
1509                cli->cl_avail_grant, cli->cl_dirty_pages << PAGE_SHIFT,
1510                cli->cl_dirty_grant);
1511 }
1512
1513 /**
1514  * The companion to osc_enter_cache(), called when @oap is no longer part of
1515  * the dirty accounting due to error.
1516  */
1517 static void osc_exit_cache(struct client_obd *cli, struct osc_async_page *oap)
1518 {
1519         spin_lock(&cli->cl_loi_list_lock);
1520         osc_release_write_grant(cli, &oap->oap_brw_page);
1521         spin_unlock(&cli->cl_loi_list_lock);
1522 }
1523
1524 /**
1525  * Non-blocking version of osc_enter_cache() that consumes grant only when it
1526  * is available.
1527  */
1528 static int osc_enter_cache_try(struct client_obd *cli,
1529                                struct osc_async_page *oap,
1530                                int bytes, int transient)
1531 {
1532         int rc;
1533
1534         OSC_DUMP_GRANT(D_CACHE, cli, "need:%d\n", bytes);
1535
1536         rc = osc_reserve_grant(cli, bytes);
1537         if (rc < 0)
1538                 return 0;
1539
1540         if (cli->cl_dirty_pages < cli->cl_dirty_max_pages &&
1541             1 + atomic_long_read(&obd_dirty_pages) <= obd_max_dirty_pages) {
1542                 osc_consume_write_grant(cli, &oap->oap_brw_page);
1543                 if (transient) {
1544                         cli->cl_dirty_transit++;
1545                         atomic_long_inc(&obd_dirty_transit_pages);
1546                         oap->oap_brw_flags |= OBD_BRW_NOCACHE;
1547                 }
1548                 rc = 1;
1549         } else {
1550                 __osc_unreserve_grant(cli, bytes, bytes);
1551                 rc = 0;
1552         }
1553         return rc;
1554 }
1555
1556 static int ocw_granted(struct client_obd *cli, struct osc_cache_waiter *ocw)
1557 {
1558         int rc;
1559         spin_lock(&cli->cl_loi_list_lock);
1560         rc = list_empty(&ocw->ocw_entry);
1561         spin_unlock(&cli->cl_loi_list_lock);
1562         return rc;
1563 }
1564
1565 /**
1566  * The main entry to reserve dirty page accounting. Usually the grant reserved
1567  * in this function will be freed in bulk in osc_free_grant() unless it fails
1568  * to add osc cache, in that case, it will be freed in osc_exit_cache().
1569  *
1570  * The process will be put into sleep if it's already run out of grant.
1571  */
1572 static int osc_enter_cache(const struct lu_env *env, struct client_obd *cli,
1573                            struct osc_async_page *oap, int bytes)
1574 {
1575         struct osc_object       *osc = oap->oap_obj;
1576         struct lov_oinfo        *loi = osc->oo_oinfo;
1577         struct osc_cache_waiter  ocw;
1578         struct l_wait_info       lwi;
1579         int                      rc = -EDQUOT;
1580         ENTRY;
1581
1582         lwi = LWI_TIMEOUT_INTR(cfs_time_seconds(AT_OFF ? obd_timeout : at_max),
1583                                NULL, LWI_ON_SIGNAL_NOOP, NULL);
1584
1585         OSC_DUMP_GRANT(D_CACHE, cli, "need:%d\n", bytes);
1586
1587         spin_lock(&cli->cl_loi_list_lock);
1588
1589         /* force the caller to try sync io.  this can jump the list
1590          * of queued writes and create a discontiguous rpc stream */
1591         if (OBD_FAIL_CHECK(OBD_FAIL_OSC_NO_GRANT) ||
1592             cli->cl_dirty_max_pages == 0 ||
1593             cli->cl_ar.ar_force_sync || loi->loi_ar.ar_force_sync) {
1594                 OSC_DUMP_GRANT(D_CACHE, cli, "forced sync i/o\n");
1595                 GOTO(out, rc = -EDQUOT);
1596         }
1597
1598         /* Hopefully normal case - cache space and write credits available */
1599         if (osc_enter_cache_try(cli, oap, bytes, 0)) {
1600                 OSC_DUMP_GRANT(D_CACHE, cli, "granted from cache\n");
1601                 GOTO(out, rc = 0);
1602         }
1603
1604         /* We can get here for two reasons: too many dirty pages in cache, or
1605          * run out of grants. In both cases we should write dirty pages out.
1606          * Adding a cache waiter will trigger urgent write-out no matter what
1607          * RPC size will be.
1608          * The exiting condition is no avail grants and no dirty pages caching,
1609          * that really means there is no space on the OST. */
1610         init_waitqueue_head(&ocw.ocw_waitq);
1611         ocw.ocw_oap   = oap;
1612         ocw.ocw_grant = bytes;
1613         while (cli->cl_dirty_pages > 0 || cli->cl_w_in_flight > 0) {
1614                 list_add_tail(&ocw.ocw_entry, &cli->cl_cache_waiters);
1615                 ocw.ocw_rc = 0;
1616                 spin_unlock(&cli->cl_loi_list_lock);
1617
1618                 osc_io_unplug_async(env, cli, NULL);
1619
1620                 CDEBUG(D_CACHE, "%s: sleeping for cache space @ %p for %p\n",
1621                        cli_name(cli), &ocw, oap);
1622
1623                 rc = l_wait_event(ocw.ocw_waitq, ocw_granted(cli, &ocw), &lwi);
1624
1625                 spin_lock(&cli->cl_loi_list_lock);
1626
1627                 if (rc < 0) {
1628                         /* l_wait_event is interrupted by signal or timed out */
1629                         list_del_init(&ocw.ocw_entry);
1630                         break;
1631                 }
1632                 LASSERT(list_empty(&ocw.ocw_entry));
1633                 rc = ocw.ocw_rc;
1634
1635                 if (rc != -EDQUOT)
1636                         break;
1637                 if (osc_enter_cache_try(cli, oap, bytes, 0)) {
1638                         rc = 0;
1639                         break;
1640                 }
1641         }
1642
1643         switch (rc) {
1644         case 0:
1645                 OSC_DUMP_GRANT(D_CACHE, cli, "finally got grant space\n");
1646                 break;
1647         case -ETIMEDOUT:
1648                 OSC_DUMP_GRANT(D_CACHE, cli,
1649                                "timeout, fall back to sync i/o\n");
1650                 osc_extent_tree_dump(D_CACHE, osc);
1651                 /* fall back to synchronous I/O */
1652                 rc = -EDQUOT;
1653                 break;
1654         case -EINTR:
1655                 /* Ensures restartability - LU-3581 */
1656                 OSC_DUMP_GRANT(D_CACHE, cli, "interrupted\n");
1657                 rc = -ERESTARTSYS;
1658                 break;
1659         case -EDQUOT:
1660                 OSC_DUMP_GRANT(D_CACHE, cli,
1661                                "no grant space, fall back to sync i/o\n");
1662                 break;
1663         default:
1664                 CDEBUG(D_CACHE, "%s: event for cache space @ %p never arrived "
1665                        "due to %d, fall back to sync i/o\n",
1666                        cli_name(cli), &ocw, rc);
1667                 break;
1668         }
1669         EXIT;
1670 out:
1671         spin_unlock(&cli->cl_loi_list_lock);
1672         RETURN(rc);
1673 }
1674
1675 /* caller must hold loi_list_lock */
1676 void osc_wake_cache_waiters(struct client_obd *cli)
1677 {
1678         struct list_head *l, *tmp;
1679         struct osc_cache_waiter *ocw;
1680
1681         ENTRY;
1682         list_for_each_safe(l, tmp, &cli->cl_cache_waiters) {
1683                 ocw = list_entry(l, struct osc_cache_waiter, ocw_entry);
1684                 list_del_init(&ocw->ocw_entry);
1685
1686                 ocw->ocw_rc = -EDQUOT;
1687                 /* we can't dirty more */
1688                 if ((cli->cl_dirty_pages  >= cli->cl_dirty_max_pages) ||
1689                     (1 + atomic_long_read(&obd_dirty_pages) >
1690                      obd_max_dirty_pages)) {
1691                         CDEBUG(D_CACHE, "no dirty room: dirty: %ld "
1692                                "osc max %ld, sys max %ld\n",
1693                                cli->cl_dirty_pages, cli->cl_dirty_max_pages,
1694                                obd_max_dirty_pages);
1695                         goto wakeup;
1696                 }
1697
1698                 if (osc_enter_cache_try(cli, ocw->ocw_oap, ocw->ocw_grant, 0))
1699                         ocw->ocw_rc = 0;
1700 wakeup:
1701                 CDEBUG(D_CACHE, "wake up %p for oap %p, avail grant %ld, %d\n",
1702                        ocw, ocw->ocw_oap, cli->cl_avail_grant, ocw->ocw_rc);
1703
1704                 wake_up(&ocw->ocw_waitq);
1705         }
1706
1707         EXIT;
1708 }
1709 EXPORT_SYMBOL(osc_wake_cache_waiters);
1710
1711 static int osc_max_rpc_in_flight(struct client_obd *cli, struct osc_object *osc)
1712 {
1713         int hprpc = !!list_empty(&osc->oo_hp_exts);
1714         return rpcs_in_flight(cli) >= cli->cl_max_rpcs_in_flight + hprpc;
1715 }
1716
1717 /* This maintains the lists of pending pages to read/write for a given object
1718  * (lop).  This is used by osc_check_rpcs->osc_next_obj() and osc_list_maint()
1719  * to quickly find objects that are ready to send an RPC. */
1720 static int osc_makes_rpc(struct client_obd *cli, struct osc_object *osc,
1721                          int cmd)
1722 {
1723         int invalid_import = 0;
1724         ENTRY;
1725
1726         /* if we have an invalid import we want to drain the queued pages
1727          * by forcing them through rpcs that immediately fail and complete
1728          * the pages.  recovery relies on this to empty the queued pages
1729          * before canceling the locks and evicting down the llite pages */
1730         if ((cli->cl_import == NULL || cli->cl_import->imp_invalid))
1731                 invalid_import = 1;
1732
1733         if (cmd & OBD_BRW_WRITE) {
1734                 if (atomic_read(&osc->oo_nr_writes) == 0)
1735                         RETURN(0);
1736                 if (invalid_import) {
1737                         CDEBUG(D_CACHE, "invalid import forcing RPC\n");
1738                         RETURN(1);
1739                 }
1740                 if (!list_empty(&osc->oo_hp_exts)) {
1741                         CDEBUG(D_CACHE, "high prio request forcing RPC\n");
1742                         RETURN(1);
1743                 }
1744                 if (!list_empty(&osc->oo_urgent_exts)) {
1745                         CDEBUG(D_CACHE, "urgent request forcing RPC\n");
1746                         RETURN(1);
1747                 }
1748                 /* trigger a write rpc stream as long as there are dirtiers
1749                  * waiting for space.  as they're waiting, they're not going to
1750                  * create more pages to coalesce with what's waiting.. */
1751                 if (!list_empty(&cli->cl_cache_waiters)) {
1752                         CDEBUG(D_CACHE, "cache waiters forcing RPC\n");
1753                         RETURN(1);
1754                 }
1755                 if (!list_empty(&osc->oo_full_exts)) {
1756                         CDEBUG(D_CACHE, "full extent ready, make an RPC\n");
1757                         RETURN(1);
1758                 }
1759         } else {
1760                 if (atomic_read(&osc->oo_nr_reads) == 0)
1761                         RETURN(0);
1762                 if (invalid_import) {
1763                         CDEBUG(D_CACHE, "invalid import forcing RPC\n");
1764                         RETURN(1);
1765                 }
1766                 /* all read are urgent. */
1767                 if (!list_empty(&osc->oo_reading_exts))
1768                         RETURN(1);
1769         }
1770
1771         RETURN(0);
1772 }
1773
1774 static void osc_update_pending(struct osc_object *obj, int cmd, int delta)
1775 {
1776         struct client_obd *cli = osc_cli(obj);
1777         if (cmd & OBD_BRW_WRITE) {
1778                 atomic_add(delta, &obj->oo_nr_writes);
1779                 atomic_add(delta, &cli->cl_pending_w_pages);
1780                 LASSERT(atomic_read(&obj->oo_nr_writes) >= 0);
1781         } else {
1782                 atomic_add(delta, &obj->oo_nr_reads);
1783                 atomic_add(delta, &cli->cl_pending_r_pages);
1784                 LASSERT(atomic_read(&obj->oo_nr_reads) >= 0);
1785         }
1786         OSC_IO_DEBUG(obj, "update pending cmd %d delta %d.\n", cmd, delta);
1787 }
1788
1789 static int osc_makes_hprpc(struct osc_object *obj)
1790 {
1791         return !list_empty(&obj->oo_hp_exts);
1792 }
1793
1794 static void on_list(struct list_head *item, struct list_head *list,
1795                     int should_be_on)
1796 {
1797         if (list_empty(item) && should_be_on)
1798                 list_add_tail(item, list);
1799         else if (!list_empty(item) && !should_be_on)
1800                 list_del_init(item);
1801 }
1802
1803 /* maintain the osc's cli list membership invariants so that osc_send_oap_rpc
1804  * can find pages to build into rpcs quickly */
1805 static int __osc_list_maint(struct client_obd *cli, struct osc_object *osc)
1806 {
1807         if (osc_makes_hprpc(osc)) {
1808                 /* HP rpc */
1809                 on_list(&osc->oo_ready_item, &cli->cl_loi_ready_list, 0);
1810                 on_list(&osc->oo_hp_ready_item, &cli->cl_loi_hp_ready_list, 1);
1811         } else {
1812                 on_list(&osc->oo_hp_ready_item, &cli->cl_loi_hp_ready_list, 0);
1813                 on_list(&osc->oo_ready_item, &cli->cl_loi_ready_list,
1814                         osc_makes_rpc(cli, osc, OBD_BRW_WRITE) ||
1815                         osc_makes_rpc(cli, osc, OBD_BRW_READ));
1816         }
1817
1818         on_list(&osc->oo_write_item, &cli->cl_loi_write_list,
1819                 atomic_read(&osc->oo_nr_writes) > 0);
1820
1821         on_list(&osc->oo_read_item, &cli->cl_loi_read_list,
1822                 atomic_read(&osc->oo_nr_reads) > 0);
1823
1824         return osc_is_ready(osc);
1825 }
1826
1827 static int osc_list_maint(struct client_obd *cli, struct osc_object *osc)
1828 {
1829         int is_ready;
1830
1831         spin_lock(&cli->cl_loi_list_lock);
1832         is_ready = __osc_list_maint(cli, osc);
1833         spin_unlock(&cli->cl_loi_list_lock);
1834
1835         return is_ready;
1836 }
1837
1838 /* this is trying to propogate async writeback errors back up to the
1839  * application.  As an async write fails we record the error code for later if
1840  * the app does an fsync.  As long as errors persist we force future rpcs to be
1841  * sync so that the app can get a sync error and break the cycle of queueing
1842  * pages for which writeback will fail. */
1843 static void osc_process_ar(struct osc_async_rc *ar, __u64 xid,
1844                            int rc)
1845 {
1846         if (rc) {
1847                 if (!ar->ar_rc)
1848                         ar->ar_rc = rc;
1849
1850                 ar->ar_force_sync = 1;
1851                 ar->ar_min_xid = ptlrpc_sample_next_xid();
1852                 return;
1853
1854         }
1855
1856         if (ar->ar_force_sync && (xid >= ar->ar_min_xid))
1857                 ar->ar_force_sync = 0;
1858 }
1859
1860 /* this must be called holding the loi list lock to give coverage to exit_cache,
1861  * async_flag maintenance, and oap_request */
1862 static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
1863                               struct osc_async_page *oap, int sent, int rc)
1864 {
1865         struct osc_object *osc = oap->oap_obj;
1866         struct lov_oinfo  *loi = osc->oo_oinfo;
1867         __u64 xid = 0;
1868
1869         ENTRY;
1870         if (oap->oap_request != NULL) {
1871                 xid = ptlrpc_req_xid(oap->oap_request);
1872                 ptlrpc_req_finished(oap->oap_request);
1873                 oap->oap_request = NULL;
1874         }
1875
1876         /* As the transfer for this page is being done, clear the flags */
1877         spin_lock(&oap->oap_lock);
1878         oap->oap_async_flags = 0;
1879         spin_unlock(&oap->oap_lock);
1880         oap->oap_interrupted = 0;
1881
1882         if (oap->oap_cmd & OBD_BRW_WRITE && xid > 0) {
1883                 spin_lock(&cli->cl_loi_list_lock);
1884                 osc_process_ar(&cli->cl_ar, xid, rc);
1885                 osc_process_ar(&loi->loi_ar, xid, rc);
1886                 spin_unlock(&cli->cl_loi_list_lock);
1887         }
1888
1889         rc = osc_completion(env, oap, oap->oap_cmd, rc);
1890         if (rc)
1891                 CERROR("completion on oap %p obj %p returns %d.\n",
1892                        oap, osc, rc);
1893
1894         EXIT;
1895 }
1896
1897 struct extent_rpc_data {
1898         struct list_head        *erd_rpc_list;
1899         unsigned int            erd_page_count;
1900         unsigned int            erd_max_pages;
1901         unsigned int            erd_max_chunks;
1902         unsigned int            erd_max_extents;
1903 };
1904
1905 static inline unsigned osc_extent_chunks(const struct osc_extent *ext)
1906 {
1907         struct client_obd *cli = osc_cli(ext->oe_obj);
1908         unsigned ppc_bits = cli->cl_chunkbits - PAGE_SHIFT;
1909
1910         return (ext->oe_end >> ppc_bits) - (ext->oe_start >> ppc_bits) + 1;
1911 }
1912
1913 /**
1914  * Try to add extent to one RPC. We need to think about the following things:
1915  * - # of pages must not be over max_pages_per_rpc
1916  * - extent must be compatible with previous ones
1917  */
1918 static int try_to_add_extent_for_io(struct client_obd *cli,
1919                                     struct osc_extent *ext,
1920                                     struct extent_rpc_data *data)
1921 {
1922         struct osc_extent *tmp;
1923         unsigned int chunk_count;
1924         struct osc_async_page *oap = list_first_entry(&ext->oe_pages,
1925                                                       struct osc_async_page,
1926                                                       oap_pending_item);
1927         ENTRY;
1928
1929         EASSERT((ext->oe_state == OES_CACHE || ext->oe_state == OES_LOCK_DONE),
1930                 ext);
1931         OSC_EXTENT_DUMP(D_CACHE, ext, "trying to add this extent\n");
1932
1933         if (data->erd_max_extents == 0)
1934                 RETURN(0);
1935
1936         chunk_count = osc_extent_chunks(ext);
1937         EASSERTF(data->erd_page_count != 0 ||
1938                  chunk_count <= data->erd_max_chunks, ext,
1939                  "The first extent to be fit in a RPC contains %u chunks, "
1940                  "which is over the limit %u.\n", chunk_count,
1941                  data->erd_max_chunks);
1942         if (chunk_count > data->erd_max_chunks)
1943                 RETURN(0);
1944
1945         data->erd_max_pages = max(ext->oe_mppr, data->erd_max_pages);
1946         EASSERTF(data->erd_page_count != 0 ||
1947                 ext->oe_nr_pages <= data->erd_max_pages, ext,
1948                 "The first extent to be fit in a RPC contains %u pages, "
1949                 "which is over the limit %u.\n", ext->oe_nr_pages,
1950                 data->erd_max_pages);
1951         if (data->erd_page_count + ext->oe_nr_pages > data->erd_max_pages)
1952                 RETURN(0);
1953
1954         list_for_each_entry(tmp, data->erd_rpc_list, oe_link) {
1955                 struct osc_async_page *oap2;
1956                 oap2 = list_first_entry(&tmp->oe_pages, struct osc_async_page,
1957                                         oap_pending_item);
1958                 EASSERT(tmp->oe_owner == current, tmp);
1959 #if 0
1960                 if (overlapped(tmp, ext)) {
1961                         OSC_EXTENT_DUMP(D_ERROR, tmp, "overlapped %p.\n", ext);
1962                         EASSERT(0, ext);
1963                 }
1964 #endif
1965                 if (oap2cl_page(oap)->cp_type != oap2cl_page(oap2)->cp_type) {
1966                         CDEBUG(D_CACHE, "Do not permit different types of IO "
1967                                "in one RPC\n");
1968                         RETURN(0);
1969                 }
1970
1971                 if (tmp->oe_srvlock != ext->oe_srvlock ||
1972                     !tmp->oe_grants != !ext->oe_grants ||
1973                     tmp->oe_no_merge || ext->oe_no_merge)
1974                         RETURN(0);
1975
1976                 /* remove break for strict check */
1977                 break;
1978         }
1979
1980         data->erd_max_extents--;
1981         data->erd_max_chunks -= chunk_count;
1982         data->erd_page_count += ext->oe_nr_pages;
1983         list_move_tail(&ext->oe_link, data->erd_rpc_list);
1984         ext->oe_owner = current;
1985         RETURN(1);
1986 }
1987
1988 static inline unsigned osc_max_write_chunks(const struct client_obd *cli)
1989 {
1990         /*
1991          * LU-8135:
1992          *
1993          * The maximum size of a single transaction is about 64MB in ZFS.
1994          * #define DMU_MAX_ACCESS (64 * 1024 * 1024)
1995          *
1996          * Since ZFS is a copy-on-write file system, a single dirty page in
1997          * a chunk will result in the rewrite of the whole chunk, therefore
1998          * an RPC shouldn't be allowed to contain too many chunks otherwise
1999          * it will make transaction size much bigger than 64MB, especially
2000          * with big block size for ZFS.
2001          *
2002          * This piece of code is to make sure that OSC won't send write RPCs
2003          * with too many chunks. The maximum chunk size that an RPC can cover
2004          * is set to PTLRPC_MAX_BRW_SIZE, which is defined to 16MB. Ideally
2005          * OST should tell the client what the biggest transaction size is,
2006          * but it's good enough for now.
2007          *
2008          * This limitation doesn't apply to ldiskfs, which allows as many
2009          * chunks in one RPC as we want. However, it won't have any benefits
2010          * to have too many discontiguous pages in one RPC.
2011          *
2012          * An osc_extent won't cover over a RPC size, so the chunks in an
2013          * osc_extent won't bigger than PTLRPC_MAX_BRW_SIZE >> chunkbits.
2014          */
2015         return PTLRPC_MAX_BRW_SIZE >> cli->cl_chunkbits;
2016 }
2017
2018 /**
2019  * In order to prevent multiple ptlrpcd from breaking contiguous extents,
2020  * get_write_extent() takes all appropriate extents in atomic.
2021  *
2022  * The following policy is used to collect extents for IO:
2023  * 1. Add as many HP extents as possible;
2024  * 2. Add the first urgent extent in urgent extent list and take it out of
2025  *    urgent list;
2026  * 3. Add subsequent extents of this urgent extent;
2027  * 4. If urgent list is not empty, goto 2;
2028  * 5. Traverse the extent tree from the 1st extent;
2029  * 6. Above steps exit if there is no space in this RPC.
2030  */
2031 static unsigned int get_write_extents(struct osc_object *obj,
2032                                       struct list_head *rpclist)
2033 {
2034         struct client_obd *cli = osc_cli(obj);
2035         struct osc_extent *ext;
2036         struct extent_rpc_data data = {
2037                 .erd_rpc_list   = rpclist,
2038                 .erd_page_count = 0,
2039                 .erd_max_pages  = cli->cl_max_pages_per_rpc,
2040                 .erd_max_chunks = osc_max_write_chunks(cli),
2041                 .erd_max_extents = 256,
2042         };
2043
2044         LASSERT(osc_object_is_locked(obj));
2045         while (!list_empty(&obj->oo_hp_exts)) {
2046                 ext = list_entry(obj->oo_hp_exts.next, struct osc_extent,
2047                                  oe_link);
2048                 LASSERT(ext->oe_state == OES_CACHE);
2049                 if (!try_to_add_extent_for_io(cli, ext, &data))
2050                         return data.erd_page_count;
2051                 EASSERT(ext->oe_nr_pages <= data.erd_max_pages, ext);
2052         }
2053         if (data.erd_page_count == data.erd_max_pages)
2054                 return data.erd_page_count;
2055
2056         while (!list_empty(&obj->oo_urgent_exts)) {
2057                 ext = list_entry(obj->oo_urgent_exts.next,
2058                                  struct osc_extent, oe_link);
2059                 if (!try_to_add_extent_for_io(cli, ext, &data))
2060                         return data.erd_page_count;
2061         }
2062         if (data.erd_page_count == data.erd_max_pages)
2063                 return data.erd_page_count;
2064
2065         /* One key difference between full extents and other extents: full
2066          * extents can usually only be added if the rpclist was empty, so if we
2067          * can't add one, we continue on to trying to add normal extents.  This
2068          * is so we don't miss adding extra extents to an RPC containing high
2069          * priority or urgent extents. */
2070         while (!list_empty(&obj->oo_full_exts)) {
2071                 ext = list_entry(obj->oo_full_exts.next,
2072                                  struct osc_extent, oe_link);
2073                 if (!try_to_add_extent_for_io(cli, ext, &data))
2074                         break;
2075         }
2076         if (data.erd_page_count == data.erd_max_pages)
2077                 return data.erd_page_count;
2078
2079         ext = first_extent(obj);
2080         while (ext != NULL) {
2081                 if ((ext->oe_state != OES_CACHE) ||
2082                     /* this extent may be already in current rpclist */
2083                     (!list_empty(&ext->oe_link) && ext->oe_owner != NULL)) {
2084                         ext = next_extent(ext);
2085                         continue;
2086                 }
2087
2088                 if (!try_to_add_extent_for_io(cli, ext, &data))
2089                         return data.erd_page_count;
2090
2091                 ext = next_extent(ext);
2092         }
2093         return data.erd_page_count;
2094 }
2095
2096 static int
2097 osc_send_write_rpc(const struct lu_env *env, struct client_obd *cli,
2098                    struct osc_object *osc)
2099 __must_hold(osc)
2100 {
2101         struct list_head   rpclist = LIST_HEAD_INIT(rpclist);
2102         struct osc_extent *ext;
2103         struct osc_extent *tmp;
2104         struct osc_extent *first = NULL;
2105         unsigned int page_count = 0;
2106         int srvlock = 0;
2107         int rc = 0;
2108         ENTRY;
2109
2110         LASSERT(osc_object_is_locked(osc));
2111
2112         page_count = get_write_extents(osc, &rpclist);
2113         LASSERT(equi(page_count == 0, list_empty(&rpclist)));
2114
2115         if (list_empty(&rpclist))
2116                 RETURN(0);
2117
2118         osc_update_pending(osc, OBD_BRW_WRITE, -page_count);
2119
2120         list_for_each_entry(ext, &rpclist, oe_link) {
2121                 LASSERT(ext->oe_state == OES_CACHE ||
2122                         ext->oe_state == OES_LOCK_DONE);
2123                 if (ext->oe_state == OES_CACHE)
2124                         osc_extent_state_set(ext, OES_LOCKING);
2125                 else
2126                         osc_extent_state_set(ext, OES_RPC);
2127         }
2128
2129         /* we're going to grab page lock, so release object lock because
2130          * lock order is page lock -> object lock. */
2131         osc_object_unlock(osc);
2132
2133         list_for_each_entry_safe(ext, tmp, &rpclist, oe_link) {
2134                 if (ext->oe_state == OES_LOCKING) {
2135                         rc = osc_extent_make_ready(env, ext);
2136                         if (unlikely(rc < 0)) {
2137                                 list_del_init(&ext->oe_link);
2138                                 osc_extent_finish(env, ext, 0, rc);
2139                                 continue;
2140                         }
2141                 }
2142                 if (first == NULL) {
2143                         first = ext;
2144                         srvlock = ext->oe_srvlock;
2145                 } else {
2146                         LASSERT(srvlock == ext->oe_srvlock);
2147                 }
2148         }
2149
2150         if (!list_empty(&rpclist)) {
2151                 LASSERT(page_count > 0);
2152                 rc = osc_build_rpc(env, cli, &rpclist, OBD_BRW_WRITE);
2153                 LASSERT(list_empty(&rpclist));
2154         }
2155
2156         osc_object_lock(osc);
2157         RETURN(rc);
2158 }
2159
2160 /**
2161  * prepare pages for ASYNC io and put pages in send queue.
2162  *
2163  * \param cmd OBD_BRW_* macroses
2164  * \param lop pending pages
2165  *
2166  * \return zero if no page added to send queue.
2167  * \return 1 if pages successfully added to send queue.
2168  * \return negative on errors.
2169  */
2170 static int
2171 osc_send_read_rpc(const struct lu_env *env, struct client_obd *cli,
2172                   struct osc_object *osc)
2173 __must_hold(osc)
2174 {
2175         struct osc_extent *ext;
2176         struct osc_extent *next;
2177         struct list_head rpclist = LIST_HEAD_INIT(rpclist);
2178         struct extent_rpc_data data = {
2179                 .erd_rpc_list   = &rpclist,
2180                 .erd_page_count = 0,
2181                 .erd_max_pages  = cli->cl_max_pages_per_rpc,
2182                 .erd_max_chunks = UINT_MAX,
2183                 .erd_max_extents = UINT_MAX,
2184         };
2185         int rc = 0;
2186         ENTRY;
2187
2188         LASSERT(osc_object_is_locked(osc));
2189         list_for_each_entry_safe(ext, next, &osc->oo_reading_exts, oe_link) {
2190                 EASSERT(ext->oe_state == OES_LOCK_DONE, ext);
2191                 if (!try_to_add_extent_for_io(cli, ext, &data))
2192                         break;
2193                 osc_extent_state_set(ext, OES_RPC);
2194                 EASSERT(ext->oe_nr_pages <= data.erd_max_pages, ext);
2195         }
2196         LASSERT(data.erd_page_count <= data.erd_max_pages);
2197
2198         osc_update_pending(osc, OBD_BRW_READ, -data.erd_page_count);
2199
2200         if (!list_empty(&rpclist)) {
2201                 osc_object_unlock(osc);
2202
2203                 rc = osc_build_rpc(env, cli, &rpclist, OBD_BRW_READ);
2204                 LASSERT(list_empty(&rpclist));
2205
2206                 osc_object_lock(osc);
2207         }
2208         RETURN(rc);
2209 }
2210
2211 #define list_to_obj(list, item) ({                                            \
2212         struct list_head *__tmp = (list)->next;                               \
2213         list_del_init(__tmp);                                         \
2214         list_entry(__tmp, struct osc_object, oo_##item);                      \
2215 })
2216
2217 /* This is called by osc_check_rpcs() to find which objects have pages that
2218  * we could be sending.  These lists are maintained by osc_makes_rpc(). */
2219 static struct osc_object *osc_next_obj(struct client_obd *cli)
2220 {
2221         ENTRY;
2222
2223         /* First return objects that have blocked locks so that they
2224          * will be flushed quickly and other clients can get the lock,
2225          * then objects which have pages ready to be stuffed into RPCs */
2226         if (!list_empty(&cli->cl_loi_hp_ready_list))
2227                 RETURN(list_to_obj(&cli->cl_loi_hp_ready_list, hp_ready_item));
2228         if (!list_empty(&cli->cl_loi_ready_list))
2229                 RETURN(list_to_obj(&cli->cl_loi_ready_list, ready_item));
2230
2231         /* then if we have cache waiters, return all objects with queued
2232          * writes.  This is especially important when many small files
2233          * have filled up the cache and not been fired into rpcs because
2234          * they don't pass the nr_pending/object threshhold */
2235         if (!list_empty(&cli->cl_cache_waiters) &&
2236             !list_empty(&cli->cl_loi_write_list))
2237                 RETURN(list_to_obj(&cli->cl_loi_write_list, write_item));
2238
2239         /* then return all queued objects when we have an invalid import
2240          * so that they get flushed */
2241         if (cli->cl_import == NULL || cli->cl_import->imp_invalid) {
2242                 if (!list_empty(&cli->cl_loi_write_list))
2243                         RETURN(list_to_obj(&cli->cl_loi_write_list,
2244                                            write_item));
2245                 if (!list_empty(&cli->cl_loi_read_list))
2246                         RETURN(list_to_obj(&cli->cl_loi_read_list,
2247                                            read_item));
2248         }
2249         RETURN(NULL);
2250 }
2251
2252 /* called with the loi list lock held */
2253 static void osc_check_rpcs(const struct lu_env *env, struct client_obd *cli)
2254 __must_hold(&cli->cl_loi_list_lock)
2255 {
2256         struct osc_object *osc;
2257         int rc = 0;
2258         ENTRY;
2259
2260         while ((osc = osc_next_obj(cli)) != NULL) {
2261                 struct cl_object *obj = osc2cl(osc);
2262                 struct lu_ref_link link;
2263
2264                 OSC_IO_DEBUG(osc, "%lu in flight\n", rpcs_in_flight(cli));
2265
2266                 if (osc_max_rpc_in_flight(cli, osc)) {
2267                         __osc_list_maint(cli, osc);
2268                         break;
2269                 }
2270
2271                 cl_object_get(obj);
2272                 spin_unlock(&cli->cl_loi_list_lock);
2273                 lu_object_ref_add_at(&obj->co_lu, &link, "check", current);
2274
2275                 /* attempt some read/write balancing by alternating between
2276                  * reads and writes in an object.  The makes_rpc checks here
2277                  * would be redundant if we were getting read/write work items
2278                  * instead of objects.  we don't want send_oap_rpc to drain a
2279                  * partial read pending queue when we're given this object to
2280                  * do io on writes while there are cache waiters */
2281                 osc_object_lock(osc);
2282                 if (osc_makes_rpc(cli, osc, OBD_BRW_WRITE)) {
2283                         rc = osc_send_write_rpc(env, cli, osc);
2284                         if (rc < 0) {
2285                                 CERROR("Write request failed with %d\n", rc);
2286
2287                                 /* osc_send_write_rpc failed, mostly because of
2288                                  * memory pressure.
2289                                  *
2290                                  * It can't break here, because if:
2291                                  *  - a page was submitted by osc_io_submit, so
2292                                  *    page locked;
2293                                  *  - no request in flight
2294                                  *  - no subsequent request
2295                                  * The system will be in live-lock state,
2296                                  * because there is no chance to call
2297                                  * osc_io_unplug() and osc_check_rpcs() any
2298                                  * more. pdflush can't help in this case,
2299                                  * because it might be blocked at grabbing
2300                                  * the page lock as we mentioned.
2301                                  *
2302                                  * Anyway, continue to drain pages. */
2303                                 /* break; */
2304                         }
2305                 }
2306                 if (osc_makes_rpc(cli, osc, OBD_BRW_READ)) {
2307                         rc = osc_send_read_rpc(env, cli, osc);
2308                         if (rc < 0)
2309                                 CERROR("Read request failed with %d\n", rc);
2310                 }
2311                 osc_object_unlock(osc);
2312
2313                 osc_list_maint(cli, osc);
2314                 lu_object_ref_del_at(&obj->co_lu, &link, "check", current);
2315                 cl_object_put(env, obj);
2316
2317                 spin_lock(&cli->cl_loi_list_lock);
2318         }
2319 }
2320
2321 int osc_io_unplug0(const struct lu_env *env, struct client_obd *cli,
2322                    struct osc_object *osc, int async)
2323 {
2324         int rc = 0;
2325
2326         if (osc != NULL && osc_list_maint(cli, osc) == 0)
2327                 return 0;
2328
2329         if (!async) {
2330                 spin_lock(&cli->cl_loi_list_lock);
2331                 osc_check_rpcs(env, cli);
2332                 spin_unlock(&cli->cl_loi_list_lock);
2333         } else {
2334                 CDEBUG(D_CACHE, "Queue writeback work for client %p.\n", cli);
2335                 LASSERT(cli->cl_writeback_work != NULL);
2336                 rc = ptlrpcd_queue_work(cli->cl_writeback_work);
2337         }
2338         return rc;
2339 }
2340 EXPORT_SYMBOL(osc_io_unplug0);
2341
2342 int osc_prep_async_page(struct osc_object *osc, struct osc_page *ops,
2343                         struct page *page, loff_t offset)
2344 {
2345         struct obd_export     *exp = osc_export(osc);
2346         struct osc_async_page *oap = &ops->ops_oap;
2347         ENTRY;
2348
2349         if (!page)
2350                 return cfs_size_round(sizeof(*oap));
2351
2352         oap->oap_magic = OAP_MAGIC;
2353         oap->oap_cli = &exp->exp_obd->u.cli;
2354         oap->oap_obj = osc;
2355
2356         oap->oap_page = page;
2357         oap->oap_obj_off = offset;
2358         LASSERT(!(offset & ~PAGE_MASK));
2359
2360         if (cfs_capable(CFS_CAP_SYS_RESOURCE))
2361                 oap->oap_brw_flags = OBD_BRW_NOQUOTA;
2362
2363         INIT_LIST_HEAD(&oap->oap_pending_item);
2364         INIT_LIST_HEAD(&oap->oap_rpc_item);
2365
2366         spin_lock_init(&oap->oap_lock);
2367         CDEBUG(D_INFO, "oap %p page %p obj off %llu\n",
2368                oap, page, oap->oap_obj_off);
2369         RETURN(0);
2370 }
2371 EXPORT_SYMBOL(osc_prep_async_page);
2372
2373 int osc_queue_async_io(const struct lu_env *env, struct cl_io *io,
2374                        struct osc_page *ops)
2375 {
2376         struct osc_io *oio = osc_env_io(env);
2377         struct osc_extent     *ext = NULL;
2378         struct osc_async_page *oap = &ops->ops_oap;
2379         struct client_obd     *cli = oap->oap_cli;
2380         struct osc_object     *osc = oap->oap_obj;
2381         pgoff_t index;
2382         unsigned int tmp;
2383         unsigned int grants = 0;
2384         u32    brw_flags = OBD_BRW_ASYNC;
2385         int    cmd = OBD_BRW_WRITE;
2386         int    need_release = 0;
2387         int    rc = 0;
2388         ENTRY;
2389
2390         if (oap->oap_magic != OAP_MAGIC)
2391                 RETURN(-EINVAL);
2392
2393         if (cli->cl_import == NULL || cli->cl_import->imp_invalid)
2394                 RETURN(-EIO);
2395
2396         if (!list_empty(&oap->oap_pending_item) ||
2397             !list_empty(&oap->oap_rpc_item))
2398                 RETURN(-EBUSY);
2399
2400         /* Set the OBD_BRW_SRVLOCK before the page is queued. */
2401         brw_flags |= ops->ops_srvlock ? OBD_BRW_SRVLOCK : 0;
2402         if (cfs_capable(CFS_CAP_SYS_RESOURCE)) {
2403                 brw_flags |= OBD_BRW_NOQUOTA;
2404                 cmd |= OBD_BRW_NOQUOTA;
2405         }
2406
2407         /* check if the file's owner/group is over quota */
2408         if (!(cmd & OBD_BRW_NOQUOTA)) {
2409                 struct cl_object *obj;
2410                 struct cl_attr   *attr;
2411                 unsigned int qid[LL_MAXQUOTAS];
2412
2413                 obj = cl_object_top(&osc->oo_cl);
2414                 attr = &osc_env_info(env)->oti_attr;
2415
2416                 cl_object_attr_lock(obj);
2417                 rc = cl_object_attr_get(env, obj, attr);
2418                 cl_object_attr_unlock(obj);
2419
2420                 qid[USRQUOTA] = attr->cat_uid;
2421                 qid[GRPQUOTA] = attr->cat_gid;
2422                 qid[PRJQUOTA] = attr->cat_projid;
2423                 if (rc == 0 && osc_quota_chkdq(cli, qid) == NO_QUOTA)
2424                         rc = -EDQUOT;
2425                 if (rc)
2426                         RETURN(rc);
2427         }
2428
2429         oap->oap_cmd = cmd;
2430         oap->oap_page_off = ops->ops_from;
2431         oap->oap_count = ops->ops_to - ops->ops_from;
2432         /* No need to hold a lock here,
2433          * since this page is not in any list yet. */
2434         oap->oap_async_flags = 0;
2435         oap->oap_brw_flags = brw_flags;
2436
2437         OSC_IO_DEBUG(osc, "oap %p page %p added for cmd %d\n",
2438                      oap, oap->oap_page, oap->oap_cmd & OBD_BRW_RWMASK);
2439
2440         index = osc_index(oap2osc(oap));
2441
2442         /* Add this page into extent by the following steps:
2443          * 1. if there exists an active extent for this IO, mostly this page
2444          *    can be added to the active extent and sometimes we need to
2445          *    expand extent to accomodate this page;
2446          * 2. otherwise, a new extent will be allocated. */
2447
2448         ext = oio->oi_active;
2449         if (ext != NULL && ext->oe_start <= index && ext->oe_max_end >= index) {
2450                 /* one chunk plus extent overhead must be enough to write this
2451                  * page */
2452                 grants = (1 << cli->cl_chunkbits) + cli->cl_grant_extent_tax;
2453                 if (ext->oe_end >= index)
2454                         grants = 0;
2455
2456                 /* it doesn't need any grant to dirty this page */
2457                 spin_lock(&cli->cl_loi_list_lock);
2458                 rc = osc_enter_cache_try(cli, oap, grants, 0);
2459                 spin_unlock(&cli->cl_loi_list_lock);
2460                 if (rc == 0) { /* try failed */
2461                         grants = 0;
2462                         need_release = 1;
2463                 } else if (ext->oe_end < index) {
2464                         tmp = grants;
2465                         /* try to expand this extent */
2466                         rc = osc_extent_expand(ext, index, &tmp);
2467                         if (rc < 0) {
2468                                 need_release = 1;
2469                                 /* don't free reserved grant */
2470                         } else {
2471                                 OSC_EXTENT_DUMP(D_CACHE, ext,
2472                                                 "expanded for %lu.\n", index);
2473                                 osc_unreserve_grant(cli, grants, tmp);
2474                                 grants = 0;
2475                         }
2476                 }
2477                 rc = 0;
2478         } else if (ext != NULL) {
2479                 /* index is located outside of active extent */
2480                 need_release = 1;
2481         }
2482         if (need_release) {
2483                 osc_extent_release(env, ext);
2484                 oio->oi_active = NULL;
2485                 ext = NULL;
2486         }
2487
2488         if (ext == NULL) {
2489                 tmp = (1 << cli->cl_chunkbits) + cli->cl_grant_extent_tax;
2490
2491                 /* try to find new extent to cover this page */
2492                 LASSERT(oio->oi_active == NULL);
2493                 /* we may have allocated grant for this page if we failed
2494                  * to expand the previous active extent. */
2495                 LASSERT(ergo(grants > 0, grants >= tmp));
2496
2497                 rc = 0;
2498                 if (grants == 0) {
2499                         /* we haven't allocated grant for this page. */
2500                         rc = osc_enter_cache(env, cli, oap, tmp);
2501                         if (rc == 0)
2502                                 grants = tmp;
2503                 }
2504
2505                 tmp = grants;
2506                 if (rc == 0) {
2507                         ext = osc_extent_find(env, osc, index, &tmp);
2508                         if (IS_ERR(ext)) {
2509                                 LASSERT(tmp == grants);
2510                                 osc_exit_cache(cli, oap);
2511                                 rc = PTR_ERR(ext);
2512                                 ext = NULL;
2513                         } else {
2514                                 oio->oi_active = ext;
2515                         }
2516                 }
2517                 if (grants > 0)
2518                         osc_unreserve_grant(cli, grants, tmp);
2519         }
2520
2521         LASSERT(ergo(rc == 0, ext != NULL));
2522         if (ext != NULL) {
2523                 EASSERTF(ext->oe_end >= index && ext->oe_start <= index,
2524                          ext, "index = %lu.\n", index);
2525                 LASSERT((oap->oap_brw_flags & OBD_BRW_FROM_GRANT) != 0);
2526
2527                 osc_object_lock(osc);
2528                 if (ext->oe_nr_pages == 0)
2529                         ext->oe_srvlock = ops->ops_srvlock;
2530                 else
2531                         LASSERT(ext->oe_srvlock == ops->ops_srvlock);
2532                 ++ext->oe_nr_pages;
2533                 list_add_tail(&oap->oap_pending_item, &ext->oe_pages);
2534                 osc_object_unlock(osc);
2535         }
2536
2537         RETURN(rc);
2538 }
2539
2540 int osc_teardown_async_page(const struct lu_env *env,
2541                             struct osc_object *obj, struct osc_page *ops)
2542 {
2543         struct osc_async_page *oap = &ops->ops_oap;
2544         int rc = 0;
2545         ENTRY;
2546
2547         LASSERT(oap->oap_magic == OAP_MAGIC);
2548
2549         CDEBUG(D_INFO, "teardown oap %p page %p at index %lu.\n",
2550                oap, ops, osc_index(oap2osc(oap)));
2551
2552         if (!list_empty(&oap->oap_rpc_item)) {
2553                 CDEBUG(D_CACHE, "oap %p is not in cache.\n", oap);
2554                 rc = -EBUSY;
2555         } else if (!list_empty(&oap->oap_pending_item)) {
2556                 struct osc_extent *ext = NULL;
2557
2558                 osc_object_lock(obj);
2559                 ext = osc_extent_lookup(obj, osc_index(oap2osc(oap)));
2560                 osc_object_unlock(obj);
2561                 /* only truncated pages are allowed to be taken out.
2562                  * See osc_extent_truncate() and osc_cache_truncate_start()
2563                  * for details. */
2564                 if (ext != NULL && ext->oe_state != OES_TRUNC) {
2565                         OSC_EXTENT_DUMP(D_ERROR, ext, "trunc at %lu.\n",
2566                                         osc_index(oap2osc(oap)));
2567                         rc = -EBUSY;
2568                 }
2569                 if (ext != NULL)
2570                         osc_extent_put(env, ext);
2571         }
2572         RETURN(rc);
2573 }
2574
2575 /**
2576  * This is called when a page is picked up by kernel to write out.
2577  *
2578  * We should find out the corresponding extent and add the whole extent
2579  * into urgent list. The extent may be being truncated or used, handle it
2580  * carefully.
2581  */
2582 int osc_flush_async_page(const struct lu_env *env, struct cl_io *io,
2583                          struct osc_page *ops)
2584 {
2585         struct osc_extent *ext   = NULL;
2586         struct osc_object *obj   = cl2osc(ops->ops_cl.cpl_obj);
2587         struct cl_page    *cp    = ops->ops_cl.cpl_page;
2588         pgoff_t            index = osc_index(ops);
2589         struct osc_async_page *oap = &ops->ops_oap;
2590         bool unplug = false;
2591         int rc = 0;
2592         ENTRY;
2593
2594         osc_object_lock(obj);
2595         ext = osc_extent_lookup(obj, index);
2596         if (ext == NULL) {
2597                 osc_extent_tree_dump(D_ERROR, obj);
2598                 LASSERTF(0, "page index %lu is NOT covered.\n", index);
2599         }
2600
2601         switch (ext->oe_state) {
2602         case OES_RPC:
2603         case OES_LOCK_DONE:
2604                 CL_PAGE_DEBUG(D_ERROR, env, cp, "flush an in-rpc page?\n");
2605                 LASSERT(0);
2606                 break;
2607         case OES_LOCKING:
2608                 /* If we know this extent is being written out, we should abort
2609                  * so that the writer can make this page ready. Otherwise, there
2610                  * exists a deadlock problem because other process can wait for
2611                  * page writeback bit holding page lock; and meanwhile in
2612                  * vvp_page_make_ready(), we need to grab page lock before
2613                  * really sending the RPC. */
2614         case OES_TRUNC:
2615                 /* race with truncate, page will be redirtied */
2616         case OES_ACTIVE:
2617                 /* The extent is active so we need to abort and let the caller
2618                  * re-dirty the page. If we continued on here, and we were the
2619                  * one making the extent active, we could deadlock waiting for
2620                  * the page writeback to clear but it won't because the extent
2621                  * is active and won't be written out. */
2622                 GOTO(out, rc = -EAGAIN);
2623         default:
2624                 break;
2625         }
2626
2627         rc = cl_page_prep(env, io, cp, CRT_WRITE);
2628         if (rc)
2629                 GOTO(out, rc);
2630
2631         spin_lock(&oap->oap_lock);
2632         oap->oap_async_flags |= ASYNC_READY|ASYNC_URGENT;
2633         spin_unlock(&oap->oap_lock);
2634
2635         if (memory_pressure_get())
2636                 ext->oe_memalloc = 1;
2637
2638         ext->oe_urgent = 1;
2639         if (ext->oe_state == OES_CACHE) {
2640                 OSC_EXTENT_DUMP(D_CACHE, ext,
2641                                 "flush page %p make it urgent.\n", oap);
2642                 if (list_empty(&ext->oe_link))
2643                         list_add_tail(&ext->oe_link, &obj->oo_urgent_exts);
2644                 unplug = true;
2645         }
2646         rc = 0;
2647         EXIT;
2648
2649 out:
2650         osc_object_unlock(obj);
2651         osc_extent_put(env, ext);
2652         if (unplug)
2653                 osc_io_unplug_async(env, osc_cli(obj), obj);
2654         return rc;
2655 }
2656
2657 /**
2658  * this is called when a sync waiter receives an interruption.  Its job is to
2659  * get the caller woken as soon as possible.  If its page hasn't been put in an
2660  * rpc yet it can dequeue immediately.  Otherwise it has to mark the rpc as
2661  * desiring interruption which will forcefully complete the rpc once the rpc
2662  * has timed out.
2663  */
2664 int osc_cancel_async_page(const struct lu_env *env, struct osc_page *ops)
2665 {
2666         struct osc_async_page *oap = &ops->ops_oap;
2667         struct osc_object     *obj = oap->oap_obj;
2668         struct client_obd     *cli = osc_cli(obj);
2669         struct osc_extent     *ext;
2670         struct osc_extent     *found = NULL;
2671         struct list_head            *plist;
2672         pgoff_t index = osc_index(ops);
2673         int     rc = -EBUSY;
2674         int     cmd;
2675         ENTRY;
2676
2677         LASSERT(!oap->oap_interrupted);
2678         oap->oap_interrupted = 1;
2679
2680         /* Find out the caching extent */
2681         osc_object_lock(obj);
2682         if (oap->oap_cmd & OBD_BRW_WRITE) {
2683                 plist = &obj->oo_urgent_exts;
2684                 cmd   = OBD_BRW_WRITE;
2685         } else {
2686                 plist = &obj->oo_reading_exts;
2687                 cmd   = OBD_BRW_READ;
2688         }
2689         list_for_each_entry(ext, plist, oe_link) {
2690                 if (ext->oe_start <= index && ext->oe_end >= index) {
2691                         LASSERT(ext->oe_state == OES_LOCK_DONE);
2692                         /* For OES_LOCK_DONE state extent, it has already held
2693                          * a refcount for RPC. */
2694                         found = osc_extent_get(ext);
2695                         break;
2696                 }
2697         }
2698         if (found != NULL) {
2699                 list_del_init(&found->oe_link);
2700                 osc_update_pending(obj, cmd, -found->oe_nr_pages);
2701                 osc_object_unlock(obj);
2702
2703                 osc_extent_finish(env, found, 0, -EINTR);
2704                 osc_extent_put(env, found);
2705                 rc = 0;
2706         } else {
2707                 osc_object_unlock(obj);
2708                 /* ok, it's been put in an rpc. only one oap gets a request
2709                  * reference */
2710                 if (oap->oap_request != NULL) {
2711                         ptlrpc_mark_interrupted(oap->oap_request);
2712                         ptlrpcd_wake(oap->oap_request);
2713                         ptlrpc_req_finished(oap->oap_request);
2714                         oap->oap_request = NULL;
2715                 }
2716         }
2717
2718         osc_list_maint(cli, obj);
2719         RETURN(rc);
2720 }
2721
2722 int osc_queue_sync_pages(const struct lu_env *env, struct osc_object *obj,
2723                          struct list_head *list, int cmd, int brw_flags)
2724 {
2725         struct client_obd     *cli = osc_cli(obj);
2726         struct osc_extent     *ext;
2727         struct osc_async_page *oap;
2728         int     page_count = 0;
2729         int     mppr       = cli->cl_max_pages_per_rpc;
2730         bool    can_merge   = true;
2731         pgoff_t start      = CL_PAGE_EOF;
2732         pgoff_t end        = 0;
2733         ENTRY;
2734
2735         list_for_each_entry(oap, list, oap_pending_item) {
2736                 struct osc_page *opg = oap2osc_page(oap);
2737                 pgoff_t index = osc_index(opg);
2738
2739                 if (index > end)
2740                         end = index;
2741                 if (index < start)
2742                         start = index;
2743                 ++page_count;
2744                 mppr <<= (page_count > mppr);
2745
2746                 if (unlikely(opg->ops_from > 0 || opg->ops_to < PAGE_SIZE))
2747                         can_merge = false;
2748         }
2749
2750         ext = osc_extent_alloc(obj);
2751         if (ext == NULL) {
2752                 struct osc_async_page *tmp;
2753
2754                 list_for_each_entry_safe(oap, tmp, list, oap_pending_item) {
2755                         list_del_init(&oap->oap_pending_item);
2756                         osc_ap_completion(env, cli, oap, 0, -ENOMEM);
2757                 }
2758                 RETURN(-ENOMEM);
2759         }
2760
2761         ext->oe_rw = !!(cmd & OBD_BRW_READ);
2762         ext->oe_sync = 1;
2763         ext->oe_no_merge = !can_merge;
2764         ext->oe_urgent = 1;
2765         ext->oe_start = start;
2766         ext->oe_end = ext->oe_max_end = end;
2767         ext->oe_obj = obj;
2768         ext->oe_srvlock = !!(brw_flags & OBD_BRW_SRVLOCK);
2769         ext->oe_nr_pages = page_count;
2770         ext->oe_mppr = mppr;
2771         list_splice_init(list, &ext->oe_pages);
2772
2773         osc_object_lock(obj);
2774         /* Reuse the initial refcount for RPC, don't drop it */
2775         osc_extent_state_set(ext, OES_LOCK_DONE);
2776         if (cmd & OBD_BRW_WRITE) {
2777                 list_add_tail(&ext->oe_link, &obj->oo_urgent_exts);
2778                 osc_update_pending(obj, OBD_BRW_WRITE, page_count);
2779         } else {
2780                 list_add_tail(&ext->oe_link, &obj->oo_reading_exts);
2781                 osc_update_pending(obj, OBD_BRW_READ, page_count);
2782         }
2783         osc_object_unlock(obj);
2784
2785         osc_io_unplug_async(env, cli, obj);
2786         RETURN(0);
2787 }
2788
2789 /**
2790  * Called by osc_io_setattr_start() to freeze and destroy covering extents.
2791  */
2792 int osc_cache_truncate_start(const struct lu_env *env, struct osc_object *obj,
2793                              __u64 size, struct osc_extent **extp)
2794 {
2795         struct client_obd *cli = osc_cli(obj);
2796         struct osc_extent *ext;
2797         struct osc_extent *waiting = NULL;
2798         pgoff_t index;
2799         struct list_head list = LIST_HEAD_INIT(list);
2800         int result = 0;
2801         bool partial;
2802         ENTRY;
2803
2804         /* pages with index greater or equal to index will be truncated. */
2805         index = cl_index(osc2cl(obj), size);
2806         partial = size > cl_offset(osc2cl(obj), index);
2807
2808 again:
2809         osc_object_lock(obj);
2810         ext = osc_extent_search(obj, index);
2811         if (ext == NULL)
2812                 ext = first_extent(obj);
2813         else if (ext->oe_end < index)
2814                 ext = next_extent(ext);
2815         while (ext != NULL) {
2816                 EASSERT(ext->oe_state != OES_TRUNC, ext);
2817
2818                 if (ext->oe_state > OES_CACHE || ext->oe_urgent) {
2819                         /* if ext is in urgent state, it means there must exist
2820                          * a page already having been flushed by write_page().
2821                          * We have to wait for this extent because we can't
2822                          * truncate that page. */
2823                         OSC_EXTENT_DUMP(D_CACHE, ext,
2824                                         "waiting for busy extent\n");
2825                         waiting = osc_extent_get(ext);
2826                         break;
2827                 }
2828
2829                 OSC_EXTENT_DUMP(D_CACHE, ext, "try to trunc:%llu.\n", size);
2830
2831                 osc_extent_get(ext);
2832                 if (ext->oe_state == OES_ACTIVE) {
2833                         /* though we grab inode mutex for write path, but we
2834                          * release it before releasing extent(in osc_io_end()),
2835                          * so there is a race window that an extent is still
2836                          * in OES_ACTIVE when truncate starts. */
2837                         LASSERT(!ext->oe_trunc_pending);
2838                         ext->oe_trunc_pending = 1;
2839                 } else {
2840                         EASSERT(ext->oe_state == OES_CACHE, ext);
2841                         osc_extent_state_set(ext, OES_TRUNC);
2842                         osc_update_pending(obj, OBD_BRW_WRITE,
2843                                            -ext->oe_nr_pages);
2844                 }
2845                 /* This extent could be on the full extents list, that's OK */
2846                 EASSERT(!ext->oe_hp && !ext->oe_urgent, ext);
2847                 if (!list_empty(&ext->oe_link))
2848                         list_move_tail(&ext->oe_link, &list);
2849                 else
2850                         list_add_tail(&ext->oe_link, &list);
2851
2852                 ext = next_extent(ext);
2853         }
2854         osc_object_unlock(obj);
2855
2856         osc_list_maint(cli, obj);
2857
2858         while (!list_empty(&list)) {
2859                 int rc;
2860
2861                 ext = list_entry(list.next, struct osc_extent, oe_link);
2862                 list_del_init(&ext->oe_link);
2863
2864                 /* extent may be in OES_ACTIVE state because inode mutex
2865                  * is released before osc_io_end() in file write case */
2866                 if (ext->oe_state != OES_TRUNC)
2867                         osc_extent_wait(env, ext, OES_TRUNC);
2868
2869                 rc = osc_extent_truncate(ext, index, partial);
2870                 if (rc < 0) {
2871                         if (result == 0)
2872                                 result = rc;
2873
2874                         OSC_EXTENT_DUMP(D_ERROR, ext,
2875                                         "truncate error %d\n", rc);
2876                 } else if (ext->oe_nr_pages == 0) {
2877                         osc_extent_remove(ext);
2878                 } else {
2879                         /* this must be an overlapped extent which means only
2880                          * part of pages in this extent have been truncated.
2881                          */
2882                         EASSERTF(ext->oe_start <= index, ext,
2883                                  "trunc index = %lu/%d.\n", index, partial);
2884                         /* fix index to skip this partially truncated extent */
2885                         index = ext->oe_end + 1;
2886                         partial = false;
2887
2888                         /* we need to hold this extent in OES_TRUNC state so
2889                          * that no writeback will happen. This is to avoid
2890                          * BUG 17397.
2891                          * Only partial truncate can reach here, if @size is
2892                          * not zero, the caller should provide a valid @extp. */
2893                         LASSERT(*extp == NULL);
2894                         *extp = osc_extent_get(ext);
2895                         OSC_EXTENT_DUMP(D_CACHE, ext,
2896                                         "trunc at %llu\n", size);
2897                 }
2898                 osc_extent_put(env, ext);
2899         }
2900         if (waiting != NULL) {
2901                 int rc;
2902
2903                 /* ignore the result of osc_extent_wait the write initiator
2904                  * should take care of it. */
2905                 rc = osc_extent_wait(env, waiting, OES_INV);
2906                 if (rc < 0)
2907                         OSC_EXTENT_DUMP(D_CACHE, waiting, "error: %d.\n", rc);
2908
2909                 osc_extent_put(env, waiting);
2910                 waiting = NULL;
2911                 goto again;
2912         }
2913         RETURN(result);
2914 }
2915 EXPORT_SYMBOL(osc_cache_truncate_start);
2916
2917 /**
2918  * Called after osc_io_setattr_end to add oio->oi_trunc back to cache.
2919  */
2920 void osc_cache_truncate_end(const struct lu_env *env, struct osc_extent *ext)
2921 {
2922         if (ext != NULL) {
2923                 struct osc_object *obj = ext->oe_obj;
2924                 bool unplug = false;
2925
2926                 EASSERT(ext->oe_nr_pages > 0, ext);
2927                 EASSERT(ext->oe_state == OES_TRUNC, ext);
2928                 EASSERT(!ext->oe_urgent, ext);
2929
2930                 OSC_EXTENT_DUMP(D_CACHE, ext, "trunc -> cache.\n");
2931                 osc_object_lock(obj);
2932                 osc_extent_state_set(ext, OES_CACHE);
2933                 if (ext->oe_fsync_wait && !ext->oe_urgent) {
2934                         ext->oe_urgent = 1;
2935                         list_move_tail(&ext->oe_link, &obj->oo_urgent_exts);
2936                         unplug = true;
2937                 }
2938                 osc_update_pending(obj, OBD_BRW_WRITE, ext->oe_nr_pages);
2939                 osc_object_unlock(obj);
2940                 osc_extent_put(env, ext);
2941
2942                 if (unplug)
2943                         osc_io_unplug_async(env, osc_cli(obj), obj);
2944         }
2945 }
2946
2947 /**
2948  * Wait for extents in a specific range to be written out.
2949  * The caller must have called osc_cache_writeback_range() to issue IO
2950  * otherwise it will take a long time for this function to finish.
2951  *
2952  * Caller must hold inode_mutex , or cancel exclusive dlm lock so that
2953  * nobody else can dirty this range of file while we're waiting for
2954  * extents to be written.
2955  */
2956 int osc_cache_wait_range(const struct lu_env *env, struct osc_object *obj,
2957                          pgoff_t start, pgoff_t end)
2958 {
2959         struct osc_extent *ext;
2960         pgoff_t index = start;
2961         int     result = 0;
2962         ENTRY;
2963
2964 again:
2965         osc_object_lock(obj);
2966         ext = osc_extent_search(obj, index);
2967         if (ext == NULL)
2968                 ext = first_extent(obj);
2969         else if (ext->oe_end < index)
2970                 ext = next_extent(ext);
2971         while (ext != NULL) {
2972                 int rc;
2973
2974                 if (ext->oe_start > end)
2975                         break;
2976
2977                 if (!ext->oe_fsync_wait) {
2978                         ext = next_extent(ext);
2979                         continue;
2980                 }
2981
2982                 EASSERT(ergo(ext->oe_state == OES_CACHE,
2983                              ext->oe_hp || ext->oe_urgent), ext);
2984                 EASSERT(ergo(ext->oe_state == OES_ACTIVE,
2985                              !ext->oe_hp && ext->oe_urgent), ext);
2986
2987                 index = ext->oe_end + 1;
2988                 osc_extent_get(ext);
2989                 osc_object_unlock(obj);
2990
2991                 rc = osc_extent_wait(env, ext, OES_INV);
2992                 if (result == 0)
2993                         result = rc;
2994                 osc_extent_put(env, ext);
2995                 goto again;
2996         }
2997         osc_object_unlock(obj);
2998
2999         OSC_IO_DEBUG(obj, "sync file range.\n");
3000         RETURN(result);
3001 }
3002 EXPORT_SYMBOL(osc_cache_wait_range);
3003
3004 /**
3005  * Called to write out a range of osc object.
3006  *
3007  * @hp     : should be set this is caused by lock cancel;
3008  * @discard: is set if dirty pages should be dropped - file will be deleted or
3009  *         truncated, this implies there is no partially discarding extents.
3010  *
3011  * Return how many pages will be issued, or error code if error occurred.
3012  */
3013 int osc_cache_writeback_range(const struct lu_env *env, struct osc_object *obj,
3014                               pgoff_t start, pgoff_t end, int hp, int discard)
3015 {
3016         struct osc_extent *ext;
3017         struct list_head discard_list = LIST_HEAD_INIT(discard_list);
3018         bool unplug = false;
3019         int result = 0;
3020         ENTRY;
3021
3022         osc_object_lock(obj);
3023         ext = osc_extent_search(obj, start);
3024         if (ext == NULL)
3025                 ext = first_extent(obj);
3026         else if (ext->oe_end < start)
3027                 ext = next_extent(ext);
3028         while (ext != NULL) {
3029                 if (ext->oe_start > end)
3030                         break;
3031
3032                 ext->oe_fsync_wait = 1;
3033                 switch (ext->oe_state) {
3034                 case OES_CACHE:
3035                         result += ext->oe_nr_pages;
3036                         if (!discard) {
3037                                 struct list_head *list = NULL;
3038                                 if (hp) {
3039                                         EASSERT(!ext->oe_hp, ext);
3040                                         ext->oe_hp = 1;
3041                                         list = &obj->oo_hp_exts;
3042                                 } else if (!ext->oe_urgent) {
3043                                         ext->oe_urgent = 1;
3044                                         list = &obj->oo_urgent_exts;
3045                                 }
3046                                 if (list != NULL)
3047                                         list_move_tail(&ext->oe_link, list);
3048                                 unplug = true;
3049                         } else {
3050                                 /* the only discarder is lock cancelling, so
3051                                  * [start, end] must contain this extent */
3052                                 EASSERT(ext->oe_start >= start &&
3053                                         ext->oe_max_end <= end, ext);
3054                                 osc_extent_state_set(ext, OES_LOCKING);
3055                                 ext->oe_owner = current;
3056                                 list_move_tail(&ext->oe_link,
3057                                                    &discard_list);
3058                                 osc_update_pending(obj, OBD_BRW_WRITE,
3059                                                    -ext->oe_nr_pages);
3060                         }
3061                         break;
3062                 case OES_ACTIVE:
3063                         /* It's pretty bad to wait for ACTIVE extents, because
3064                          * we don't know how long we will wait for it to be
3065                          * flushed since it may be blocked at awaiting more
3066                          * grants. We do this for the correctness of fsync. */
3067                         LASSERT(hp == 0 && discard == 0);
3068                         ext->oe_urgent = 1;
3069                         break;
3070                 case OES_TRUNC:
3071                         /* this extent is being truncated, can't do anything
3072                          * for it now. it will be set to urgent after truncate
3073                          * is finished in osc_cache_truncate_end(). */
3074                 default:
3075                         break;
3076                 }
3077                 ext = next_extent(ext);
3078         }
3079         osc_object_unlock(obj);
3080
3081         LASSERT(ergo(!discard, list_empty(&discard_list)));
3082         if (!list_empty(&discard_list)) {
3083                 struct osc_extent *tmp;
3084                 int rc;
3085
3086                 osc_list_maint(osc_cli(obj), obj);
3087                 list_for_each_entry_safe(ext, tmp, &discard_list, oe_link) {
3088                         list_del_init(&ext->oe_link);
3089                         EASSERT(ext->oe_state == OES_LOCKING, ext);
3090
3091                         /* Discard caching pages. We don't actually write this
3092                          * extent out but we complete it as if we did. */
3093                         rc = osc_extent_make_ready(env, ext);
3094                         if (unlikely(rc < 0)) {
3095                                 OSC_EXTENT_DUMP(D_ERROR, ext,
3096                                                 "make_ready returned %d\n", rc);
3097                                 if (result >= 0)
3098                                         result = rc;
3099                         }
3100
3101                         /* finish the extent as if the pages were sent */
3102                         osc_extent_finish(env, ext, 0, 0);
3103                 }
3104         }
3105
3106         if (unplug)
3107                 osc_io_unplug(env, osc_cli(obj), obj);
3108
3109         if (hp || discard) {
3110                 int rc;
3111                 rc = osc_cache_wait_range(env, obj, start, end);
3112                 if (result >= 0 && rc < 0)
3113                         result = rc;
3114         }
3115
3116         OSC_IO_DEBUG(obj, "pageout [%lu, %lu], %d.\n", start, end, result);
3117         RETURN(result);
3118 }
3119 EXPORT_SYMBOL(osc_cache_writeback_range);
3120
3121 /**
3122  * Returns a list of pages by a given [start, end] of \a obj.
3123  *
3124  * \param resched If not NULL, then we give up before hogging CPU for too
3125  * long and set *resched = 1, in that case caller should implement a retry
3126  * logic.
3127  *
3128  * Gang tree lookup (radix_tree_gang_lookup()) optimization is absolutely
3129  * crucial in the face of [offset, EOF] locks.
3130  *
3131  * Return at least one page in @queue unless there is no covered page.
3132  */
3133 int osc_page_gang_lookup(const struct lu_env *env, struct cl_io *io,
3134                         struct osc_object *osc, pgoff_t start, pgoff_t end,
3135                         osc_page_gang_cbt cb, void *cbdata)
3136 {
3137         struct osc_page *ops;
3138         void            **pvec;
3139         pgoff_t         idx;
3140         unsigned int    nr;
3141         unsigned int    i;
3142         unsigned int    j;
3143         int             res = CLP_GANG_OKAY;
3144         bool            tree_lock = true;
3145         ENTRY;
3146
3147         idx = start;
3148         pvec = osc_env_info(env)->oti_pvec;
3149         spin_lock(&osc->oo_tree_lock);
3150         while ((nr = radix_tree_gang_lookup(&osc->oo_tree, pvec,
3151                                             idx, OTI_PVEC_SIZE)) > 0) {
3152                 struct cl_page *page;
3153                 bool end_of_region = false;
3154
3155                 for (i = 0, j = 0; i < nr; ++i) {
3156                         ops = pvec[i];
3157                         pvec[i] = NULL;
3158
3159                         idx = osc_index(ops);
3160                         if (idx > end) {
3161                                 end_of_region = true;
3162                                 break;
3163                         }
3164
3165                         page = ops->ops_cl.cpl_page;
3166                         LASSERT(page->cp_type == CPT_CACHEABLE);
3167                         if (page->cp_state == CPS_FREEING)
3168                                 continue;
3169
3170                         cl_page_get(page);
3171                         lu_ref_add_atomic(&page->cp_reference,
3172                                           "gang_lookup", current);
3173                         pvec[j++] = ops;
3174                 }
3175                 ++idx;
3176
3177                 /*
3178                  * Here a delicate locking dance is performed. Current thread
3179                  * holds a reference to a page, but has to own it before it
3180                  * can be placed into queue. Owning implies waiting, so
3181                  * radix-tree lock is to be released. After a wait one has to
3182                  * check that pages weren't truncated (cl_page_own() returns
3183                  * error in the latter case).
3184                  */
3185                 spin_unlock(&osc->oo_tree_lock);
3186                 tree_lock = false;
3187
3188                 for (i = 0; i < j; ++i) {
3189                         ops = pvec[i];
3190                         if (res == CLP_GANG_OKAY)
3191                                 res = (*cb)(env, io, ops, cbdata);
3192
3193                         page = ops->ops_cl.cpl_page;
3194                         lu_ref_del(&page->cp_reference, "gang_lookup", current);
3195                         cl_page_put(env, page);
3196                 }
3197                 if (nr < OTI_PVEC_SIZE || end_of_region)
3198                         break;
3199
3200                 if (res == CLP_GANG_OKAY && need_resched())
3201                         res = CLP_GANG_RESCHED;
3202                 if (res != CLP_GANG_OKAY)
3203                         break;
3204
3205                 spin_lock(&osc->oo_tree_lock);
3206                 tree_lock = true;
3207         }
3208         if (tree_lock)
3209                 spin_unlock(&osc->oo_tree_lock);
3210         RETURN(res);
3211 }
3212 EXPORT_SYMBOL(osc_page_gang_lookup);
3213
3214 /**
3215  * Check if page @page is covered by an extra lock or discard it.
3216  */
3217 static int check_and_discard_cb(const struct lu_env *env, struct cl_io *io,
3218                                 struct osc_page *ops, void *cbdata)
3219 {
3220         struct osc_thread_info *info = osc_env_info(env);
3221         struct osc_object *osc = cbdata;
3222         pgoff_t index;
3223
3224         index = osc_index(ops);
3225         if (index >= info->oti_fn_index) {
3226                 struct ldlm_lock *tmp;
3227                 struct cl_page *page = ops->ops_cl.cpl_page;
3228
3229                 /* refresh non-overlapped index */
3230                 tmp = osc_dlmlock_at_pgoff(env, osc, index,
3231                                            OSC_DAP_FL_TEST_LOCK);
3232                 if (tmp != NULL) {
3233                         __u64 end = tmp->l_policy_data.l_extent.end;
3234                         /* Cache the first-non-overlapped index so as to skip
3235                          * all pages within [index, oti_fn_index). This is safe
3236                          * because if tmp lock is canceled, it will discard
3237                          * these pages. */
3238                         info->oti_fn_index = cl_index(osc2cl(osc), end + 1);
3239                         if (end == OBD_OBJECT_EOF)
3240                                 info->oti_fn_index = CL_PAGE_EOF;
3241                         LDLM_LOCK_PUT(tmp);
3242                 } else if (cl_page_own(env, io, page) == 0) {
3243                         /* discard the page */
3244                         cl_page_discard(env, io, page);
3245                         cl_page_disown(env, io, page);
3246                 } else {
3247                         LASSERT(page->cp_state == CPS_FREEING);
3248                 }
3249         }
3250
3251         info->oti_next_index = index + 1;
3252         return CLP_GANG_OKAY;
3253 }
3254
3255 int osc_discard_cb(const struct lu_env *env, struct cl_io *io,
3256                    struct osc_page *ops, void *cbdata)
3257 {
3258         struct osc_thread_info *info = osc_env_info(env);
3259         struct cl_page *page = ops->ops_cl.cpl_page;
3260
3261         /* page is top page. */
3262         info->oti_next_index = osc_index(ops) + 1;
3263         if (cl_page_own(env, io, page) == 0) {
3264                 if (!ergo(page->cp_type == CPT_CACHEABLE,
3265                           !PageDirty(cl_page_vmpage(page))))
3266                         CL_PAGE_DEBUG(D_ERROR, env, page,
3267                                         "discard dirty page?\n");
3268
3269                 /* discard the page */
3270                 cl_page_discard(env, io, page);
3271                 cl_page_disown(env, io, page);
3272         } else {
3273                 LASSERT(page->cp_state == CPS_FREEING);
3274         }
3275
3276         return CLP_GANG_OKAY;
3277 }
3278 EXPORT_SYMBOL(osc_discard_cb);
3279
3280 /**
3281  * Discard pages protected by the given lock. This function traverses radix
3282  * tree to find all covering pages and discard them. If a page is being covered
3283  * by other locks, it should remain in cache.
3284  *
3285  * If error happens on any step, the process continues anyway (the reasoning
3286  * behind this being that lock cancellation cannot be delayed indefinitely).
3287  */
3288 int osc_lock_discard_pages(const struct lu_env *env, struct osc_object *osc,
3289                            pgoff_t start, pgoff_t end, bool discard)
3290 {
3291         struct osc_thread_info *info = osc_env_info(env);
3292         struct cl_io *io = osc_env_thread_io(env);
3293         osc_page_gang_cbt cb;
3294         int res;
3295         int result;
3296
3297         ENTRY;
3298
3299         io->ci_obj = cl_object_top(osc2cl(osc));
3300         io->ci_ignore_layout = 1;
3301         result = cl_io_init(env, io, CIT_MISC, io->ci_obj);
3302         if (result != 0)
3303                 GOTO(out, result);
3304
3305         cb = discard ? osc_discard_cb : check_and_discard_cb;
3306         info->oti_fn_index = info->oti_next_index = start;
3307         do {
3308                 res = osc_page_gang_lookup(env, io, osc,
3309                                            info->oti_next_index, end, cb, osc);
3310                 if (info->oti_next_index > end)
3311                         break;
3312
3313                 if (res == CLP_GANG_RESCHED)
3314                         cond_resched();
3315         } while (res != CLP_GANG_OKAY);
3316 out:
3317         cl_io_fini(env, io);
3318         RETURN(result);
3319 }
3320
3321
3322 /** @} osc */