lustre/osc/osc_cache.c

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see
  18  * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
  19  *
  20  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  21  * CA 95054 USA or visit www.sun.com if you need additional information or
  22  * have any questions.
  23  *
  24  * GPL HEADER END
  25  */
  26 /*
  27  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  28  * Use is subject to license terms.
  29  *
  30  * Copyright (c) 2012, 2013, Intel Corporation.
  31  *
  32  */
  33 /*
  34  * This file is part of Lustre, http://www.lustre.org/
  35  * Lustre is a trademark of Sun Microsystems, Inc.
  36  *
  37  * osc cache management.
  38  *
  39  * Author: Jinshan Xiong <jinshan.xiong@whamcloud.com>
  40  */
  41
  42 #define DEBUG_SUBSYSTEM S_OSC
  43
  44 #include "osc_cl_internal.h"
  45 #include "osc_internal.h"
  46
  47 static int extent_debug; /* set it to be true for more debug */
  48
  49 static void osc_update_pending(struct osc_object *obj, int cmd, int delta);
  50 static int osc_extent_wait(const struct lu_env *env, struct osc_extent *ext,
  51                            int state);
  52 static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
  53                               struct osc_async_page *oap, int sent, int rc);
  54 static int osc_make_ready(const struct lu_env *env, struct osc_async_page *oap,
  55                           int cmd);
  56 static int osc_refresh_count(const struct lu_env *env,
  57                              struct osc_async_page *oap, int cmd);
  58 static int osc_io_unplug_async(const struct lu_env *env,
  59                                struct client_obd *cli, struct osc_object *osc);
  60 static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
  61                            unsigned int lost_grant);
  62
  63 static void osc_extent_tree_dump0(int level, struct osc_object *obj,
  64                                   const char *func, int line);
  65 #define osc_extent_tree_dump(lvl, obj) \
  66         osc_extent_tree_dump0(lvl, obj, __func__, __LINE__)
  67
  68 /** \addtogroup osc
  69  *  @{
  70  */
  71
  72 /* ------------------ osc extent ------------------ */
  73 static inline char *ext_flags(struct osc_extent *ext, char *flags)
  74 {
  75         char *buf = flags;
  76         *buf++ = ext->oe_rw ? 'r' : 'w';
  77         if (ext->oe_intree)
  78                 *buf++ = 'i';
  79         if (ext->oe_srvlock)
  80                 *buf++ = 's';
  81         if (ext->oe_hp)
  82                 *buf++ = 'h';
  83         if (ext->oe_urgent)
  84                 *buf++ = 'u';
  85         if (ext->oe_memalloc)
  86                 *buf++ = 'm';
  87         if (ext->oe_trunc_pending)
  88                 *buf++ = 't';
  89         if (ext->oe_fsync_wait)
  90                 *buf++ = 'Y';
  91         *buf = 0;
  92         return flags;
  93 }
  94
  95 static inline char list_empty_marker(struct list_head *list)
  96 {
  97         return list_empty(list) ? '-' : '+';
  98 }
  99
 100 #define EXTSTR       "[%lu -> %lu/%lu]"
 101 #define EXTPARA(ext) (ext)->oe_start, (ext)->oe_end, (ext)->oe_max_end
 102 static const char *oes_strings[] = {
 103         "inv", "active", "cache", "locking", "lockdone", "rpc", "trunc", NULL };
 104
 105 #define OSC_EXTENT_DUMP(lvl, extent, fmt, ...) do {                     \
 106         struct osc_extent *__ext = (extent);                            \
 107         char __buf[16];                                                 \
 108                                                                         \
 109         CDEBUG(lvl,                                                     \
 110                 "extent %p@{" EXTSTR ", "                               \
 111                 "[%d|%d|%c|%s|%s|%p], [%d|%d|%c|%c|%p|%u|%p]} " fmt,    \
 112                 /* ----- extent part 0 ----- */                         \
 113                 __ext, EXTPARA(__ext),                                  \
 114                 /* ----- part 1 ----- */                                \
 115                 atomic_read(&__ext->oe_refc),                           \
 116                 atomic_read(&__ext->oe_users),                          \
 117                 list_empty_marker(&__ext->oe_link),                     \
 118                 oes_strings[__ext->oe_state], ext_flags(__ext, __buf),  \
 119                 __ext->oe_obj,                                          \
 120                 /* ----- part 2 ----- */                                \
 121                 __ext->oe_grants, __ext->oe_nr_pages,                   \
 122                 list_empty_marker(&__ext->oe_pages),                    \
 123                 waitqueue_active(&__ext->oe_waitq) ? '+' : '-',         \
 124                 __ext->oe_osclock, __ext->oe_mppr, __ext->oe_owner,     \
 125                 /* ----- part 4 ----- */                                \
 126                 ## __VA_ARGS__);                                        \
 127 } while (0)
 128
 129 #undef EASSERTF
 130 #define EASSERTF(expr, ext, fmt, args...) do {                          \
 131         if (!(expr)) {                                                  \
 132                 OSC_EXTENT_DUMP(D_ERROR, (ext), fmt, ##args);           \
 133                 osc_extent_tree_dump(D_ERROR, (ext)->oe_obj);           \
 134                 LASSERT(expr);                                          \
 135         }                                                               \
 136 } while (0)
 137
 138 #undef EASSERT
 139 #define EASSERT(expr, ext) EASSERTF(expr, ext, "\n")
 140
 141 static inline struct osc_extent *rb_extent(struct rb_node *n)
 142 {
 143         if (n == NULL)
 144                 return NULL;
 145
 146         return container_of(n, struct osc_extent, oe_node);
 147 }
 148
 149 static inline struct osc_extent *next_extent(struct osc_extent *ext)
 150 {
 151         if (ext == NULL)
 152                 return NULL;
 153
 154         LASSERT(ext->oe_intree);
 155         return rb_extent(rb_next(&ext->oe_node));
 156 }
 157
 158 static inline struct osc_extent *prev_extent(struct osc_extent *ext)
 159 {
 160         if (ext == NULL)
 161                 return NULL;
 162
 163         LASSERT(ext->oe_intree);
 164         return rb_extent(rb_prev(&ext->oe_node));
 165 }
 166
 167 static inline struct osc_extent *first_extent(struct osc_object *obj)
 168 {
 169         return rb_extent(rb_first(&obj->oo_root));
 170 }
 171
 172 /* object must be locked by caller. */
 173 static int osc_extent_sanity_check0(struct osc_extent *ext,
 174                                     const char *func, const int line)
 175 {
 176         struct osc_object *obj = ext->oe_obj;
 177         struct osc_async_page *oap;
 178         int page_count;
 179         int rc = 0;
 180
 181         if (!osc_object_is_locked(obj))
 182                 GOTO(out, rc = 9);
 183
 184         if (ext->oe_state >= OES_STATE_MAX)
 185                 GOTO(out, rc = 10);
 186
 187         if (atomic_read(&ext->oe_refc) <= 0)
 188                 GOTO(out, rc = 20);
 189
 190         if (atomic_read(&ext->oe_refc) < atomic_read(&ext->oe_users))
 191                 GOTO(out, rc = 30);
 192
 193         switch (ext->oe_state) {
 194         case OES_INV:
 195                 if (ext->oe_nr_pages > 0 || !list_empty(&ext->oe_pages))
 196                         GOTO(out, rc = 35);
 197                 GOTO(out, rc = 0);
 198                 break;
 199         case OES_ACTIVE:
 200                 if (atomic_read(&ext->oe_users) == 0)
 201                         GOTO(out, rc = 40);
 202                 if (ext->oe_hp)
 203                         GOTO(out, rc = 50);
 204                 if (ext->oe_fsync_wait && !ext->oe_urgent)
 205                         GOTO(out, rc = 55);
 206                 break;
 207         case OES_CACHE:
 208                 if (ext->oe_grants == 0)
 209                         GOTO(out, rc = 60);
 210                 if (ext->oe_fsync_wait && !ext->oe_urgent && !ext->oe_hp)
 211                         GOTO(out, rc = 65);
 212         default:
 213                 if (atomic_read(&ext->oe_users) > 0)
 214                         GOTO(out, rc = 70);
 215         }
 216
 217         if (ext->oe_max_end < ext->oe_end || ext->oe_end < ext->oe_start)
 218                 GOTO(out, rc = 80);
 219
 220         if (ext->oe_osclock == NULL && ext->oe_grants > 0)
 221                 GOTO(out, rc = 90);
 222
 223         if (ext->oe_osclock) {
 224                 struct cl_lock_descr *descr;
 225                 descr = &ext->oe_osclock->cll_descr;
 226                 if (!(descr->cld_start <= ext->oe_start &&
 227                       descr->cld_end >= ext->oe_max_end))
 228                         GOTO(out, rc = 100);
 229         }
 230
 231         if (ext->oe_nr_pages > ext->oe_mppr)
 232                 GOTO(out, rc = 105);
 233
 234         /* Do not verify page list if extent is in RPC. This is because an
 235          * in-RPC extent is supposed to be exclusively accessible w/o lock. */
 236         if (ext->oe_state > OES_CACHE)
 237                 GOTO(out, rc = 0);
 238
 239         if (!extent_debug)
 240                 GOTO(out, rc = 0);
 241
 242         page_count = 0;
 243         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
 244                 pgoff_t index = osc_index(oap2osc(oap));
 245                 ++page_count;
 246                 if (index > ext->oe_end || index < ext->oe_start)
 247                         GOTO(out, rc = 110);
 248         }
 249         if (page_count != ext->oe_nr_pages)
 250                 GOTO(out, rc = 120);
 251
 252 out:
 253         if (rc != 0)
 254                 OSC_EXTENT_DUMP(D_ERROR, ext,
 255                                 "%s:%d sanity check %p failed with rc = %d\n",
 256                                 func, line, ext, rc);
 257         return rc;
 258 }
 259
 260 #define sanity_check_nolock(ext) \
 261         osc_extent_sanity_check0(ext, __func__, __LINE__)
 262
 263 #define sanity_check(ext) ({                                                   \
 264         int __res;                                                             \
 265         osc_object_lock((ext)->oe_obj);                                        \
 266         __res = sanity_check_nolock(ext);                                      \
 267         osc_object_unlock((ext)->oe_obj);                                      \
 268         __res;                                                                 \
 269 })
 270
 271
 272 /**
 273  * sanity check - to make sure there is no overlapped extent in the tree.
 274  */
 275 static int osc_extent_is_overlapped(struct osc_object *obj,
 276                                     struct osc_extent *ext)
 277 {
 278         struct osc_extent *tmp;
 279
 280         LASSERT(osc_object_is_locked(obj));
 281
 282         if (!extent_debug)
 283                 return 0;
 284
 285         for (tmp = first_extent(obj); tmp != NULL; tmp = next_extent(tmp)) {
 286                 if (tmp == ext)
 287                         continue;
 288                 if (tmp->oe_end >= ext->oe_start &&
 289                     tmp->oe_start <= ext->oe_end)
 290                         return 1;
 291         }
 292         return 0;
 293 }
 294
 295 static void osc_extent_state_set(struct osc_extent *ext, int state)
 296 {
 297         LASSERT(osc_object_is_locked(ext->oe_obj));
 298         LASSERT(state >= OES_INV && state < OES_STATE_MAX);
 299
 300         /* Never try to sanity check a state changing extent :-) */
 301         /* LASSERT(sanity_check_nolock(ext) == 0); */
 302
 303         /* TODO: validate the state machine */
 304         ext->oe_state = state;
 305         wake_up_all(&ext->oe_waitq);
 306 }
 307
 308 static struct osc_extent *osc_extent_alloc(struct osc_object *obj)
 309 {
 310         struct osc_extent *ext;
 311
 312         OBD_SLAB_ALLOC_PTR_GFP(ext, osc_extent_kmem, GFP_IOFS);
 313         if (ext == NULL)
 314                 return NULL;
 315
 316         RB_CLEAR_NODE(&ext->oe_node);
 317         ext->oe_obj = obj;
 318         atomic_set(&ext->oe_refc, 1);
 319         atomic_set(&ext->oe_users, 0);
 320         INIT_LIST_HEAD(&ext->oe_link);
 321         ext->oe_state = OES_INV;
 322         INIT_LIST_HEAD(&ext->oe_pages);
 323         init_waitqueue_head(&ext->oe_waitq);
 324         ext->oe_osclock = NULL;
 325
 326         return ext;
 327 }
 328
 329 static void osc_extent_free(struct osc_extent *ext)
 330 {
 331         OBD_SLAB_FREE_PTR(ext, osc_extent_kmem);
 332 }
 333
 334 static struct osc_extent *osc_extent_get(struct osc_extent *ext)
 335 {
 336         LASSERT(atomic_read(&ext->oe_refc) >= 0);
 337         atomic_inc(&ext->oe_refc);
 338         return ext;
 339 }
 340
 341 static void osc_extent_put(const struct lu_env *env, struct osc_extent *ext)
 342 {
 343         LASSERT(atomic_read(&ext->oe_refc) > 0);
 344         if (atomic_dec_and_test(&ext->oe_refc)) {
 345                 LASSERT(list_empty(&ext->oe_link));
 346                 LASSERT(atomic_read(&ext->oe_users) == 0);
 347                 LASSERT(ext->oe_state == OES_INV);
 348                 LASSERT(!ext->oe_intree);
 349
 350                 if (ext->oe_osclock) {
 351                         cl_lock_put(env, ext->oe_osclock);
 352                         ext->oe_osclock = NULL;
 353                 }
 354                 osc_extent_free(ext);
 355         }
 356 }
 357
 358 /**
 359  * osc_extent_put_trust() is a special version of osc_extent_put() when
 360  * it's known that the caller is not the last user. This is to address the
 361  * problem of lacking of lu_env ;-).
 362  */
 363 static void osc_extent_put_trust(struct osc_extent *ext)
 364 {
 365         LASSERT(atomic_read(&ext->oe_refc) > 1);
 366         LASSERT(osc_object_is_locked(ext->oe_obj));
 367         atomic_dec(&ext->oe_refc);
 368 }
 369
 370 /**
 371  * Return the extent which includes pgoff @index, or return the greatest
 372  * previous extent in the tree.
 373  */
 374 static struct osc_extent *osc_extent_search(struct osc_object *obj,
 375                                             pgoff_t index)
 376 {
 377         struct rb_node    *n = obj->oo_root.rb_node;
 378         struct osc_extent *tmp, *p = NULL;
 379
 380         LASSERT(osc_object_is_locked(obj));
 381         while (n != NULL) {
 382                 tmp = rb_extent(n);
 383                 if (index < tmp->oe_start) {
 384                         n = n->rb_left;
 385                 } else if (index > tmp->oe_end) {
 386                         p = rb_extent(n);
 387                         n = n->rb_right;
 388                 } else {
 389                         return tmp;
 390                 }
 391         }
 392         return p;
 393 }
 394
 395 /*
 396  * Return the extent covering @index, otherwise return NULL.
 397  * caller must have held object lock.
 398  */
 399 static struct osc_extent *osc_extent_lookup(struct osc_object *obj,
 400                                             pgoff_t index)
 401 {
 402         struct osc_extent *ext;
 403
 404         ext = osc_extent_search(obj, index);
 405         if (ext != NULL && ext->oe_start <= index && index <= ext->oe_end)
 406                 return osc_extent_get(ext);
 407         return NULL;
 408 }
 409
 410 /* caller must have held object lock. */
 411 static void osc_extent_insert(struct osc_object *obj, struct osc_extent *ext)
 412 {
 413         struct rb_node   **n      = &obj->oo_root.rb_node;
 414         struct rb_node    *parent = NULL;
 415         struct osc_extent *tmp;
 416
 417         LASSERT(ext->oe_intree == 0);
 418         LASSERT(ext->oe_obj == obj);
 419         LASSERT(osc_object_is_locked(obj));
 420         while (*n != NULL) {
 421                 tmp = rb_extent(*n);
 422                 parent = *n;
 423
 424                 if (ext->oe_end < tmp->oe_start)
 425                         n = &(*n)->rb_left;
 426                 else if (ext->oe_start > tmp->oe_end)
 427                         n = &(*n)->rb_right;
 428                 else
 429                         EASSERTF(0, tmp, EXTSTR, EXTPARA(ext));
 430         }
 431         rb_link_node(&ext->oe_node, parent, n);
 432         rb_insert_color(&ext->oe_node, &obj->oo_root);
 433         osc_extent_get(ext);
 434         ext->oe_intree = 1;
 435 }
 436
 437 /* caller must have held object lock. */
 438 static void osc_extent_erase(struct osc_extent *ext)
 439 {
 440         struct osc_object *obj = ext->oe_obj;
 441         LASSERT(osc_object_is_locked(obj));
 442         if (ext->oe_intree) {
 443                 rb_erase(&ext->oe_node, &obj->oo_root);
 444                 ext->oe_intree = 0;
 445                 /* rbtree held a refcount */
 446                 osc_extent_put_trust(ext);
 447         }
 448 }
 449
 450 static struct osc_extent *osc_extent_hold(struct osc_extent *ext)
 451 {
 452         struct osc_object *obj = ext->oe_obj;
 453
 454         LASSERT(osc_object_is_locked(obj));
 455         LASSERT(ext->oe_state == OES_ACTIVE || ext->oe_state == OES_CACHE);
 456         if (ext->oe_state == OES_CACHE) {
 457                 osc_extent_state_set(ext, OES_ACTIVE);
 458                 osc_update_pending(obj, OBD_BRW_WRITE, -ext->oe_nr_pages);
 459         }
 460         atomic_inc(&ext->oe_users);
 461         list_del_init(&ext->oe_link);
 462         return osc_extent_get(ext);
 463 }
 464
 465 static void __osc_extent_remove(struct osc_extent *ext)
 466 {
 467         LASSERT(osc_object_is_locked(ext->oe_obj));
 468         LASSERT(list_empty(&ext->oe_pages));
 469         osc_extent_erase(ext);
 470         list_del_init(&ext->oe_link);
 471         osc_extent_state_set(ext, OES_INV);
 472         OSC_EXTENT_DUMP(D_CACHE, ext, "destroyed.\n");
 473 }
 474
 475 static void osc_extent_remove(struct osc_extent *ext)
 476 {
 477         struct osc_object *obj = ext->oe_obj;
 478
 479         osc_object_lock(obj);
 480         __osc_extent_remove(ext);
 481         osc_object_unlock(obj);
 482 }
 483
 484 /**
 485  * This function is used to merge extents to get better performance. It checks
 486  * if @cur and @victim are contiguous at chunk level.
 487  */
 488 static int osc_extent_merge(const struct lu_env *env, struct osc_extent *cur,
 489                             struct osc_extent *victim)
 490 {
 491         struct osc_object *obj = cur->oe_obj;
 492         pgoff_t chunk_start;
 493         pgoff_t chunk_end;
 494         int ppc_bits;
 495
 496         LASSERT(cur->oe_state == OES_CACHE);
 497         LASSERT(osc_object_is_locked(obj));
 498         if (victim == NULL)
 499                 return -EINVAL;
 500
 501         if (victim->oe_state != OES_CACHE || victim->oe_fsync_wait)
 502                 return -EBUSY;
 503
 504         if (cur->oe_max_end != victim->oe_max_end)
 505                 return -ERANGE;
 506
 507         LASSERT(cur->oe_osclock == victim->oe_osclock);
 508         ppc_bits = osc_cli(obj)->cl_chunkbits - PAGE_CACHE_SHIFT;
 509         chunk_start = cur->oe_start >> ppc_bits;
 510         chunk_end   = cur->oe_end   >> ppc_bits;
 511         if (chunk_start   != (victim->oe_end >> ppc_bits) + 1 &&
 512             chunk_end + 1 != victim->oe_start >> ppc_bits)
 513                 return -ERANGE;
 514
 515         OSC_EXTENT_DUMP(D_CACHE, victim, "will be merged by %p.\n", cur);
 516
 517         cur->oe_start     = min(cur->oe_start, victim->oe_start);
 518         cur->oe_end       = max(cur->oe_end,   victim->oe_end);
 519         cur->oe_grants   += victim->oe_grants;
 520         cur->oe_nr_pages += victim->oe_nr_pages;
 521         /* only the following bits are needed to merge */
 522         cur->oe_urgent   |= victim->oe_urgent;
 523         cur->oe_memalloc |= victim->oe_memalloc;
 524         list_splice_init(&victim->oe_pages, &cur->oe_pages);
 525         list_del_init(&victim->oe_link);
 526         victim->oe_nr_pages = 0;
 527
 528         osc_extent_get(victim);
 529         __osc_extent_remove(victim);
 530         osc_extent_put(env, victim);
 531
 532         OSC_EXTENT_DUMP(D_CACHE, cur, "after merging %p.\n", victim);
 533         return 0;
 534 }
 535
 536 /**
 537  * Drop user count of osc_extent, and unplug IO asynchronously.
 538  */
 539 int osc_extent_release(const struct lu_env *env, struct osc_extent *ext)
 540 {
 541         struct osc_object *obj = ext->oe_obj;
 542         int rc = 0;
 543         ENTRY;
 544
 545         LASSERT(atomic_read(&ext->oe_users) > 0);
 546         LASSERT(sanity_check(ext) == 0);
 547         LASSERT(ext->oe_grants > 0);
 548
 549         if (atomic_dec_and_lock(&ext->oe_users, &obj->oo_lock)) {
 550                 LASSERT(ext->oe_state == OES_ACTIVE);
 551                 if (ext->oe_trunc_pending) {
 552                         /* a truncate process is waiting for this extent.
 553                          * This may happen due to a race, check
 554                          * osc_cache_truncate_start(). */
 555                         osc_extent_state_set(ext, OES_TRUNC);
 556                         ext->oe_trunc_pending = 0;
 557                 } else {
 558                         osc_extent_state_set(ext, OES_CACHE);
 559                         osc_update_pending(obj, OBD_BRW_WRITE,
 560                                            ext->oe_nr_pages);
 561
 562                         /* try to merge the previous and next extent. */
 563                         osc_extent_merge(env, ext, prev_extent(ext));
 564                         osc_extent_merge(env, ext, next_extent(ext));
 565
 566                         if (ext->oe_urgent)
 567                                 list_move_tail(&ext->oe_link,
 568                                                &obj->oo_urgent_exts);
 569                 }
 570                 osc_object_unlock(obj);
 571
 572                 osc_io_unplug_async(env, osc_cli(obj), obj);
 573         }
 574         osc_extent_put(env, ext);
 575         RETURN(rc);
 576 }
 577
 578 static inline int overlapped(struct osc_extent *ex1, struct osc_extent *ex2)
 579 {
 580         return !(ex1->oe_end < ex2->oe_start || ex2->oe_end < ex1->oe_start);
 581 }
 582
 583 /**
 584  * Find or create an extent which includes @index, core function to manage
 585  * extent tree.
 586  */
 587 struct osc_extent *osc_extent_find(const struct lu_env *env,
 588                                    struct osc_object *obj, pgoff_t index,
 589                                    int *grants)
 590
 591 {
 592         struct client_obd *cli = osc_cli(obj);
 593         struct cl_lock    *lock;
 594         struct osc_extent *cur;
 595         struct osc_extent *ext;
 596         struct osc_extent *conflict = NULL;
 597         struct osc_extent *found = NULL;
 598         pgoff_t    chunk;
 599         pgoff_t    max_end;
 600         int        max_pages; /* max_pages_per_rpc */
 601         int        chunksize;
 602         int        ppc_bits; /* pages per chunk bits */
 603         int        chunk_mask;
 604         int        rc;
 605         ENTRY;
 606
 607         cur = osc_extent_alloc(obj);
 608         if (cur == NULL)
 609                 RETURN(ERR_PTR(-ENOMEM));
 610
 611         lock = cl_lock_at_pgoff(env, osc2cl(obj), index, NULL, 1, 0);
 612         LASSERT(lock != NULL);
 613         LASSERT(lock->cll_descr.cld_mode >= CLM_WRITE);
 614
 615         LASSERT(cli->cl_chunkbits >= PAGE_CACHE_SHIFT);
 616         ppc_bits   = cli->cl_chunkbits - PAGE_CACHE_SHIFT;
 617         chunk_mask = ~((1 << ppc_bits) - 1);
 618         chunksize  = 1 << cli->cl_chunkbits;
 619         chunk      = index >> ppc_bits;
 620
 621         /* align end to rpc edge, rpc size may not be a power 2 integer. */
 622         max_pages = cli->cl_max_pages_per_rpc;
 623         LASSERT((max_pages & ~chunk_mask) == 0);
 624         max_end = index - (index % max_pages) + max_pages - 1;
 625         max_end = min_t(pgoff_t, max_end, lock->cll_descr.cld_end);
 626
 627         /* initialize new extent by parameters so far */
 628         cur->oe_max_end = max_end;
 629         cur->oe_start   = index & chunk_mask;
 630         cur->oe_end     = ((index + ~chunk_mask + 1) & chunk_mask) - 1;
 631         if (cur->oe_start < lock->cll_descr.cld_start)
 632                 cur->oe_start = lock->cll_descr.cld_start;
 633         if (cur->oe_end > max_end)
 634                 cur->oe_end = max_end;
 635         cur->oe_osclock = lock;
 636         cur->oe_grants  = 0;
 637         cur->oe_mppr    = max_pages;
 638
 639         /* grants has been allocated by caller */
 640         LASSERTF(*grants >= chunksize + cli->cl_extent_tax,
 641                  "%u/%u/%u.\n", *grants, chunksize, cli->cl_extent_tax);
 642         LASSERTF((max_end - cur->oe_start) < max_pages, EXTSTR, EXTPARA(cur));
 643
 644 restart:
 645         osc_object_lock(obj);
 646         ext = osc_extent_search(obj, cur->oe_start);
 647         if (ext == NULL)
 648                 ext = first_extent(obj);
 649         while (ext != NULL) {
 650                 loff_t ext_chk_start = ext->oe_start >> ppc_bits;
 651                 loff_t ext_chk_end   = ext->oe_end   >> ppc_bits;
 652
 653                 LASSERT(sanity_check_nolock(ext) == 0);
 654                 if (chunk > ext_chk_end + 1)
 655                         break;
 656
 657                 /* if covering by different locks, no chance to match */
 658                 if (lock != ext->oe_osclock) {
 659                         EASSERTF(!overlapped(ext, cur), ext,
 660                                  EXTSTR, EXTPARA(cur));
 661
 662                         ext = next_extent(ext);
 663                         continue;
 664                 }
 665
 666                 /* discontiguous chunks? */
 667                 if (chunk + 1 < ext_chk_start) {
 668                         ext = next_extent(ext);
 669                         continue;
 670                 }
 671
 672                 /* ok, from now on, ext and cur have these attrs:
 673                  * 1. covered by the same lock
 674                  * 2. contiguous at chunk level or overlapping. */
 675
 676                 if (overlapped(ext, cur)) {
 677                         /* cur is the minimum unit, so overlapping means
 678                          * full contain. */
 679                         EASSERTF((ext->oe_start <= cur->oe_start &&
 680                                   ext->oe_end >= cur->oe_end),
 681                                  ext, EXTSTR, EXTPARA(cur));
 682
 683                         if (ext->oe_state > OES_CACHE || ext->oe_fsync_wait) {
 684                                 /* for simplicity, we wait for this extent to
 685                                  * finish before going forward. */
 686                                 conflict = osc_extent_get(ext);
 687                                 break;
 688                         }
 689
 690                         found = osc_extent_hold(ext);
 691                         break;
 692                 }
 693
 694                 /* non-overlapped extent */
 695                 if (ext->oe_state != OES_CACHE || ext->oe_fsync_wait) {
 696                         /* we can't do anything for a non OES_CACHE extent, or
 697                          * if there is someone waiting for this extent to be
 698                          * flushed, try next one. */
 699                         ext = next_extent(ext);
 700                         continue;
 701                 }
 702
 703                 /* check if they belong to the same rpc slot before trying to
 704                  * merge. the extents are not overlapped and contiguous at
 705                  * chunk level to get here. */
 706                 if (ext->oe_max_end != max_end) {
 707                         /* if they don't belong to the same RPC slot or
 708                          * max_pages_per_rpc has ever changed, do not merge. */
 709                         ext = next_extent(ext);
 710                         continue;
 711                 }
 712
 713                 /* it's required that an extent must be contiguous at chunk
 714                  * level so that we know the whole extent is covered by grant
 715                  * (the pages in the extent are NOT required to be contiguous).
 716                  * Otherwise, it will be too much difficult to know which
 717                  * chunks have grants allocated. */
 718
 719                 /* try to do front merge - extend ext's start */
 720                 if (chunk + 1 == ext_chk_start) {
 721                         /* ext must be chunk size aligned */
 722                         EASSERT((ext->oe_start & ~chunk_mask) == 0, ext);
 723
 724                         /* pull ext's start back to cover cur */
 725                         ext->oe_start   = cur->oe_start;
 726                         ext->oe_grants += chunksize;
 727                         *grants -= chunksize;
 728
 729                         found = osc_extent_hold(ext);
 730                 } else if (chunk == ext_chk_end + 1) {
 731                         /* rear merge */
 732                         ext->oe_end     = cur->oe_end;
 733                         ext->oe_grants += chunksize;
 734                         *grants -= chunksize;
 735
 736                         /* try to merge with the next one because we just fill
 737                          * in a gap */
 738                         if (osc_extent_merge(env, ext, next_extent(ext)) == 0)
 739                                 /* we can save extent tax from next extent */
 740                                 *grants += cli->cl_extent_tax;
 741
 742                         found = osc_extent_hold(ext);
 743                 }
 744                 if (found != NULL)
 745                         break;
 746
 747                 ext = next_extent(ext);
 748         }
 749
 750         osc_extent_tree_dump(D_CACHE, obj);
 751         if (found != NULL) {
 752                 LASSERT(conflict == NULL);
 753                 if (!IS_ERR(found)) {
 754                         LASSERT(found->oe_osclock == cur->oe_osclock);
 755                         OSC_EXTENT_DUMP(D_CACHE, found,
 756                                         "found caching ext for %lu.\n", index);
 757                 }
 758         } else if (conflict == NULL) {
 759                 /* create a new extent */
 760                 EASSERT(osc_extent_is_overlapped(obj, cur) == 0, cur);
 761                 cur->oe_grants = chunksize + cli->cl_extent_tax;
 762                 *grants -= cur->oe_grants;
 763                 LASSERT(*grants >= 0);
 764
 765                 cur->oe_state = OES_CACHE;
 766                 found = osc_extent_hold(cur);
 767                 osc_extent_insert(obj, cur);
 768                 OSC_EXTENT_DUMP(D_CACHE, cur, "add into tree %lu/%lu.\n",
 769                                 index, lock->cll_descr.cld_end);
 770         }
 771         osc_object_unlock(obj);
 772
 773         if (conflict != NULL) {
 774                 LASSERT(found == NULL);
 775
 776                 /* waiting for IO to finish. Please notice that it's impossible
 777                  * to be an OES_TRUNC extent. */
 778                 rc = osc_extent_wait(env, conflict, OES_INV);
 779                 osc_extent_put(env, conflict);
 780                 conflict = NULL;
 781                 if (rc < 0)
 782                         GOTO(out, found = ERR_PTR(rc));
 783
 784                 goto restart;
 785         }
 786         EXIT;
 787
 788 out:
 789         osc_extent_put(env, cur);
 790         LASSERT(*grants >= 0);
 791         return found;
 792 }
 793
 794 /**
 795  * Called when IO is finished to an extent.
 796  */
 797 int osc_extent_finish(const struct lu_env *env, struct osc_extent *ext,
 798                       int sent, int rc)
 799 {
 800         struct client_obd *cli = osc_cli(ext->oe_obj);
 801         struct osc_async_page *oap;
 802         struct osc_async_page *tmp;
 803         int nr_pages = ext->oe_nr_pages;
 804         int lost_grant = 0;
 805         int blocksize = cli->cl_import->imp_obd->obd_osfs.os_bsize ? : 4096;
 806         __u64 last_off = 0;
 807         int last_count = -1;
 808         ENTRY;
 809
 810         OSC_EXTENT_DUMP(D_CACHE, ext, "extent finished.\n");
 811
 812         ext->oe_rc = rc ?: ext->oe_nr_pages;
 813         EASSERT(ergo(rc == 0, ext->oe_state == OES_RPC), ext);
 814
 815         osc_lru_add_batch(cli, &ext->oe_pages);
 816         list_for_each_entry_safe(oap, tmp, &ext->oe_pages,
 817                                      oap_pending_item) {
 818                 list_del_init(&oap->oap_rpc_item);
 819                 list_del_init(&oap->oap_pending_item);
 820                 if (last_off <= oap->oap_obj_off) {
 821                         last_off = oap->oap_obj_off;
 822                         last_count = oap->oap_count;
 823                 }
 824
 825                 --ext->oe_nr_pages;
 826                 osc_ap_completion(env, cli, oap, sent, rc);
 827         }
 828         EASSERT(ext->oe_nr_pages == 0, ext);
 829
 830         if (!sent) {
 831                 lost_grant = ext->oe_grants;
 832         } else if (blocksize < PAGE_CACHE_SIZE &&
 833                    last_count != PAGE_CACHE_SIZE) {
 834                 /* For short writes we shouldn't count parts of pages that
 835                  * span a whole chunk on the OST side, or our accounting goes
 836                  * wrong.  Should match the code in filter_grant_check. */
 837                 int offset = last_off & ~CFS_PAGE_MASK;
 838                 int count = last_count + (offset & (blocksize - 1));
 839                 int end = (offset + last_count) & (blocksize - 1);
 840                 if (end)
 841                         count += blocksize - end;
 842
 843                 lost_grant = PAGE_CACHE_SIZE - count;
 844         }
 845         if (ext->oe_grants > 0)
 846                 osc_free_grant(cli, nr_pages, lost_grant);
 847
 848         osc_extent_remove(ext);
 849         /* put the refcount for RPC */
 850         osc_extent_put(env, ext);
 851         RETURN(0);
 852 }
 853
 854 static int extent_wait_cb(struct osc_extent *ext, int state)
 855 {
 856         int ret;
 857
 858         osc_object_lock(ext->oe_obj);
 859         ret = ext->oe_state == state;
 860         osc_object_unlock(ext->oe_obj);
 861
 862         return ret;
 863 }
 864
 865 /**
 866  * Wait for the extent's state to become @state.
 867  */
 868 static int osc_extent_wait(const struct lu_env *env, struct osc_extent *ext,
 869                            int state)
 870 {
 871         struct osc_object *obj = ext->oe_obj;
 872         struct l_wait_info lwi = LWI_TIMEOUT_INTR(cfs_time_seconds(600), NULL,
 873                                                   LWI_ON_SIGNAL_NOOP, NULL);
 874         int rc = 0;
 875         ENTRY;
 876
 877         osc_object_lock(obj);
 878         LASSERT(sanity_check_nolock(ext) == 0);
 879         /* `Kick' this extent only if the caller is waiting for it to be
 880          * written out. */
 881         if (state == OES_INV && !ext->oe_urgent && !ext->oe_hp) {
 882                 if (ext->oe_state == OES_ACTIVE) {
 883                         ext->oe_urgent = 1;
 884                 } else if (ext->oe_state == OES_CACHE) {
 885                         ext->oe_urgent = 1;
 886                         osc_extent_hold(ext);
 887                         rc = 1;
 888                 }
 889         }
 890         osc_object_unlock(obj);
 891         if (rc == 1)
 892                 osc_extent_release(env, ext);
 893
 894         /* wait for the extent until its state becomes @state */
 895         rc = l_wait_event(ext->oe_waitq, extent_wait_cb(ext, state), &lwi);
 896         if (rc == -ETIMEDOUT) {
 897                 OSC_EXTENT_DUMP(D_ERROR, ext,
 898                         "%s: wait ext to %d timedout, recovery in progress?\n",
 899                         osc_export(obj)->exp_obd->obd_name, state);
 900
 901                 lwi = LWI_INTR(NULL, NULL);
 902                 rc = l_wait_event(ext->oe_waitq, extent_wait_cb(ext, state),
 903                                   &lwi);
 904         }
 905         if (rc == 0 && ext->oe_rc < 0)
 906                 rc = ext->oe_rc;
 907         RETURN(rc);
 908 }
 909
 910 /**
 911  * Discard pages with index greater than @size. If @ext is overlapped with
 912  * @size, then partial truncate happens.
 913  */
 914 static int osc_extent_truncate(struct osc_extent *ext, pgoff_t trunc_index,
 915                                 bool partial)
 916 {
 917         struct cl_env_nest     nest;
 918         struct lu_env         *env;
 919         struct cl_io          *io;
 920         struct osc_object     *obj = ext->oe_obj;
 921         struct client_obd     *cli = osc_cli(obj);
 922         struct osc_async_page *oap;
 923         struct osc_async_page *tmp;
 924         int                    pages_in_chunk = 0;
 925         int                    ppc_bits    = cli->cl_chunkbits -
 926                                              PAGE_CACHE_SHIFT;
 927         __u64                  trunc_chunk = trunc_index >> ppc_bits;
 928         int                    grants   = 0;
 929         int                    nr_pages = 0;
 930         int                    rc       = 0;
 931         ENTRY;
 932
 933         LASSERT(sanity_check(ext) == 0);
 934         LASSERT(ext->oe_state == OES_TRUNC);
 935         LASSERT(!ext->oe_urgent);
 936
 937         /* Request new lu_env.
 938          * We can't use that env from osc_cache_truncate_start() because
 939          * it's from lov_io_sub and not fully initialized. */
 940         env = cl_env_nested_get(&nest);
 941         io  = &osc_env_info(env)->oti_io;
 942         io->ci_obj = cl_object_top(osc2cl(obj));
 943         rc = cl_io_init(env, io, CIT_MISC, io->ci_obj);
 944         if (rc < 0)
 945                 GOTO(out, rc);
 946
 947         /* discard all pages with index greater then trunc_index */
 948         list_for_each_entry_safe(oap, tmp, &ext->oe_pages,
 949                                      oap_pending_item) {
 950                 pgoff_t index = osc_index(oap2osc(oap));
 951                 struct cl_page  *page = oap2cl_page(oap);
 952
 953                 LASSERT(list_empty(&oap->oap_rpc_item));
 954
 955                 /* only discard the pages with their index greater than
 956                  * trunc_index, and ... */
 957                 if (index < trunc_index ||
 958                     (index == trunc_index && partial)) {
 959                         /* accounting how many pages remaining in the chunk
 960                          * so that we can calculate grants correctly. */
 961                         if (index >> ppc_bits == trunc_chunk)
 962                                 ++pages_in_chunk;
 963                         continue;
 964                 }
 965
 966                 list_del_init(&oap->oap_pending_item);
 967
 968                 cl_page_get(page);
 969                 lu_ref_add(&page->cp_reference, "truncate", current);
 970
 971                 if (cl_page_own(env, io, page) == 0) {
 972                         cl_page_discard(env, io, page);
 973                         cl_page_disown(env, io, page);
 974                 } else {
 975                         LASSERT(page->cp_state == CPS_FREEING);
 976                         LASSERT(0);
 977                 }
 978
 979                 lu_ref_del(&page->cp_reference, "truncate", current);
 980                 cl_page_put(env, page);
 981
 982                 --ext->oe_nr_pages;
 983                 ++nr_pages;
 984         }
 985         EASSERTF(ergo(ext->oe_start >= trunc_index + !!partial,
 986                       ext->oe_nr_pages == 0),
 987                 ext, "trunc_index %lu, partial %d\n", trunc_index, partial);
 988
 989         osc_object_lock(obj);
 990         if (ext->oe_nr_pages == 0) {
 991                 LASSERT(pages_in_chunk == 0);
 992                 grants = ext->oe_grants;
 993                 ext->oe_grants = 0;
 994         } else { /* calculate how many grants we can free */
 995                 int     chunks = (ext->oe_end >> ppc_bits) - trunc_chunk;
 996                 pgoff_t last_index;
 997
 998
 999                 /* if there is no pages in this chunk, we can also free grants
1000                  * for the last chunk */
1001                 if (pages_in_chunk == 0) {
1002                         /* if this is the 1st chunk and no pages in this chunk,
1003                          * ext->oe_nr_pages must be zero, so we should be in
1004                          * the other if-clause. */
1005                         LASSERT(trunc_chunk > 0);
1006                         --trunc_chunk;
1007                         ++chunks;
1008                 }
1009
1010                 /* this is what we can free from this extent */
1011                 grants          = chunks << cli->cl_chunkbits;
1012                 ext->oe_grants -= grants;
1013                 last_index      = ((trunc_chunk + 1) << ppc_bits) - 1;
1014                 ext->oe_end     = min(last_index, ext->oe_max_end);
1015                 LASSERT(ext->oe_end >= ext->oe_start);
1016                 LASSERT(ext->oe_grants > 0);
1017         }
1018         osc_object_unlock(obj);
1019
1020         if (grants > 0 || nr_pages > 0)
1021                 osc_free_grant(cli, nr_pages, grants);
1022
1023 out:
1024         cl_io_fini(env, io);
1025         cl_env_nested_put(&nest, env);
1026         RETURN(rc);
1027 }
1028
1029 /**
1030  * This function is used to make the extent prepared for transfer.
1031  * A race with flusing page - ll_writepage() has to be handled cautiously.
1032  */
1033 static int osc_extent_make_ready(const struct lu_env *env,
1034                                  struct osc_extent *ext)
1035 {
1036         struct osc_async_page *oap;
1037         struct osc_async_page *last = NULL;
1038         struct osc_object *obj = ext->oe_obj;
1039         int page_count = 0;
1040         int rc;
1041         ENTRY;
1042
1043         /* we're going to grab page lock, so object lock must not be taken. */
1044         LASSERT(sanity_check(ext) == 0);
1045         /* in locking state, any process should not touch this extent. */
1046         EASSERT(ext->oe_state == OES_LOCKING, ext);
1047         EASSERT(ext->oe_owner != NULL, ext);
1048
1049         OSC_EXTENT_DUMP(D_CACHE, ext, "make ready\n");
1050
1051         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
1052                 ++page_count;
1053                 if (last == NULL || last->oap_obj_off < oap->oap_obj_off)
1054                         last = oap;
1055
1056                 /* checking ASYNC_READY is race safe */
1057                 if ((oap->oap_async_flags & ASYNC_READY) != 0)
1058                         continue;
1059
1060                 rc = osc_make_ready(env, oap, OBD_BRW_WRITE);
1061                 switch (rc) {
1062                 case 0:
1063                         spin_lock(&oap->oap_lock);
1064                         oap->oap_async_flags |= ASYNC_READY;
1065                         spin_unlock(&oap->oap_lock);
1066                         break;
1067                 case -EALREADY:
1068                         LASSERT((oap->oap_async_flags & ASYNC_READY) != 0);
1069                         break;
1070                 default:
1071                         LASSERTF(0, "unknown return code: %d\n", rc);
1072                 }
1073         }
1074
1075         LASSERT(page_count == ext->oe_nr_pages);
1076         LASSERT(last != NULL);
1077         /* the last page is the only one we need to refresh its count by
1078          * the size of file. */
1079         if (!(last->oap_async_flags & ASYNC_COUNT_STABLE)) {
1080                 last->oap_count = osc_refresh_count(env, last, OBD_BRW_WRITE);
1081                 LASSERT(last->oap_count > 0);
1082                 LASSERT(last->oap_page_off + last->oap_count <= PAGE_CACHE_SIZE);
1083                 spin_lock(&last->oap_lock);
1084                 last->oap_async_flags |= ASYNC_COUNT_STABLE;
1085                 spin_unlock(&last->oap_lock);
1086         }
1087
1088         /* for the rest of pages, we don't need to call osf_refresh_count()
1089          * because it's known they are not the last page */
1090         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
1091                 if (!(oap->oap_async_flags & ASYNC_COUNT_STABLE)) {
1092                         oap->oap_count = PAGE_CACHE_SIZE - oap->oap_page_off;
1093                         spin_lock(&oap->oap_lock);
1094                         oap->oap_async_flags |= ASYNC_COUNT_STABLE;
1095                         spin_unlock(&oap->oap_lock);
1096                 }
1097         }
1098
1099         osc_object_lock(obj);
1100         osc_extent_state_set(ext, OES_RPC);
1101         osc_object_unlock(obj);
1102         /* get a refcount for RPC. */
1103         osc_extent_get(ext);
1104
1105         RETURN(0);
1106 }
1107
1108 /**
1109  * Quick and simple version of osc_extent_find(). This function is frequently
1110  * called to expand the extent for the same IO. To expand the extent, the
1111  * page index must be in the same or next chunk of ext->oe_end.
1112  */
1113 static int osc_extent_expand(struct osc_extent *ext, pgoff_t index, int *grants)
1114 {
1115         struct osc_object *obj = ext->oe_obj;
1116         struct client_obd *cli = osc_cli(obj);
1117         struct osc_extent *next;
1118         int ppc_bits = cli->cl_chunkbits - PAGE_CACHE_SHIFT;
1119         pgoff_t chunk = index >> ppc_bits;
1120         pgoff_t end_chunk;
1121         pgoff_t end_index;
1122         int chunksize = 1 << cli->cl_chunkbits;
1123         int rc = 0;
1124         ENTRY;
1125
1126         LASSERT(ext->oe_max_end >= index && ext->oe_start <= index);
1127         osc_object_lock(obj);
1128         LASSERT(sanity_check_nolock(ext) == 0);
1129         end_chunk = ext->oe_end >> ppc_bits;
1130         if (chunk > end_chunk + 1)
1131                 GOTO(out, rc = -ERANGE);
1132
1133         if (end_chunk >= chunk)
1134                 GOTO(out, rc = 0);
1135
1136         LASSERT(end_chunk + 1 == chunk);
1137         /* try to expand this extent to cover @index */
1138         end_index = min(ext->oe_max_end, ((chunk + 1) << ppc_bits) - 1);
1139
1140         next = next_extent(ext);
1141         if (next != NULL && next->oe_start <= end_index)
1142                 /* complex mode - overlapped with the next extent,
1143                  * this case will be handled by osc_extent_find() */
1144                 GOTO(out, rc = -EAGAIN);
1145
1146         ext->oe_end = end_index;
1147         ext->oe_grants += chunksize;
1148         *grants -= chunksize;
1149         LASSERT(*grants >= 0);
1150         EASSERTF(osc_extent_is_overlapped(obj, ext) == 0, ext,
1151                  "overlapped after expanding for %lu.\n", index);
1152         EXIT;
1153
1154 out:
1155         osc_object_unlock(obj);
1156         RETURN(rc);
1157 }
1158
1159 static void osc_extent_tree_dump0(int level, struct osc_object *obj,
1160                                   const char *func, int line)
1161 {
1162         struct osc_extent *ext;
1163         int cnt;
1164
1165         CDEBUG(level, "Dump object %p extents at %s:%d, mppr: %u.\n",
1166                obj, func, line, osc_cli(obj)->cl_max_pages_per_rpc);
1167
1168         /* osc_object_lock(obj); */
1169         cnt = 1;
1170         for (ext = first_extent(obj); ext != NULL; ext = next_extent(ext))
1171                 OSC_EXTENT_DUMP(level, ext, "in tree %d.\n", cnt++);
1172
1173         cnt = 1;
1174         list_for_each_entry(ext, &obj->oo_hp_exts, oe_link)
1175                 OSC_EXTENT_DUMP(level, ext, "hp %d.\n", cnt++);
1176
1177         cnt = 1;
1178         list_for_each_entry(ext, &obj->oo_urgent_exts, oe_link)
1179                 OSC_EXTENT_DUMP(level, ext, "urgent %d.\n", cnt++);
1180
1181         cnt = 1;
1182         list_for_each_entry(ext, &obj->oo_reading_exts, oe_link)
1183                 OSC_EXTENT_DUMP(level, ext, "reading %d.\n", cnt++);
1184         /* osc_object_unlock(obj); */
1185 }
1186
1187 /* ------------------ osc extent end ------------------ */
1188
1189 static inline int osc_is_ready(struct osc_object *osc)
1190 {
1191         return !list_empty(&osc->oo_ready_item) ||
1192                !list_empty(&osc->oo_hp_ready_item);
1193 }
1194
1195 #define OSC_IO_DEBUG(OSC, STR, args...)                                        \
1196         CDEBUG(D_CACHE, "obj %p ready %d|%c|%c wr %d|%c|%c rd %d|%c " STR,     \
1197                (OSC), osc_is_ready(OSC),                                       \
1198                list_empty_marker(&(OSC)->oo_hp_ready_item),                    \
1199                list_empty_marker(&(OSC)->oo_ready_item),                       \
1200                atomic_read(&(OSC)->oo_nr_writes),                              \
1201                list_empty_marker(&(OSC)->oo_hp_exts),                          \
1202                list_empty_marker(&(OSC)->oo_urgent_exts),                      \
1203                atomic_read(&(OSC)->oo_nr_reads),                               \
1204                list_empty_marker(&(OSC)->oo_reading_exts),                     \
1205                ##args)
1206
1207 static int osc_make_ready(const struct lu_env *env, struct osc_async_page *oap,
1208                           int cmd)
1209 {
1210         struct osc_page *opg  = oap2osc_page(oap);
1211         struct cl_page  *page = oap2cl_page(oap);
1212         int result;
1213
1214         LASSERT(cmd == OBD_BRW_WRITE); /* no cached reads */
1215
1216         ENTRY;
1217         result = cl_page_make_ready(env, page, CRT_WRITE);
1218         if (result == 0)
1219                 opg->ops_submit_time = cfs_time_current();
1220         RETURN(result);
1221 }
1222
1223 static int osc_refresh_count(const struct lu_env *env,
1224                              struct osc_async_page *oap, int cmd)
1225 {
1226         struct osc_page  *opg = oap2osc_page(oap);
1227         pgoff_t index = osc_index(oap2osc(oap));
1228         struct cl_object *obj;
1229         struct cl_attr   *attr = &osc_env_info(env)->oti_attr;
1230
1231         int result;
1232         loff_t kms;
1233
1234         /* readpage queues with _COUNT_STABLE, shouldn't get here. */
1235         LASSERT(!(cmd & OBD_BRW_READ));
1236         LASSERT(opg != NULL);
1237         obj = opg->ops_cl.cpl_obj;
1238
1239         cl_object_attr_lock(obj);
1240         result = cl_object_attr_get(env, obj, attr);
1241         cl_object_attr_unlock(obj);
1242         if (result < 0)
1243                 return result;
1244         kms = attr->cat_kms;
1245         if (cl_offset(obj, index) >= kms)
1246                 /* catch race with truncate */
1247                 return 0;
1248         else if (cl_offset(obj, index + 1) > kms)
1249                 /* catch sub-page write at end of file */
1250                 return kms % PAGE_CACHE_SIZE;
1251         else
1252                 return PAGE_CACHE_SIZE;
1253 }
1254
1255 static int osc_completion(const struct lu_env *env, struct osc_async_page *oap,
1256                           int cmd, int rc)
1257 {
1258         struct osc_page   *opg  = oap2osc_page(oap);
1259         struct cl_page    *page = oap2cl_page(oap);
1260         struct osc_object *obj  = cl2osc(opg->ops_cl.cpl_obj);
1261         enum cl_req_type   crt;
1262         int srvlock;
1263
1264         ENTRY;
1265
1266         cmd &= ~OBD_BRW_NOQUOTA;
1267         LASSERTF(equi(page->cp_state == CPS_PAGEIN,  cmd == OBD_BRW_READ),
1268                  "cp_state:%u, cmd:%d\n", page->cp_state, cmd);
1269         LASSERTF(equi(page->cp_state == CPS_PAGEOUT, cmd == OBD_BRW_WRITE),
1270                 "cp_state:%u, cmd:%d\n", page->cp_state, cmd);
1271         LASSERT(opg->ops_transfer_pinned);
1272
1273         /*
1274          * page->cp_req can be NULL if io submission failed before
1275          * cl_req was allocated.
1276          */
1277         if (page->cp_req != NULL)
1278                 cl_req_page_done(env, page);
1279         LASSERT(page->cp_req == NULL);
1280
1281         crt = cmd == OBD_BRW_READ ? CRT_READ : CRT_WRITE;
1282         /* Clear opg->ops_transfer_pinned before VM lock is released. */
1283         opg->ops_transfer_pinned = 0;
1284
1285         spin_lock(&obj->oo_seatbelt);
1286         LASSERT(opg->ops_submitter != NULL);
1287         LASSERT(!list_empty(&opg->ops_inflight));
1288         list_del_init(&opg->ops_inflight);
1289         opg->ops_submitter = NULL;
1290         spin_unlock(&obj->oo_seatbelt);
1291
1292         opg->ops_submit_time = 0;
1293         srvlock = oap->oap_brw_flags & OBD_BRW_SRVLOCK;
1294
1295         /* statistic */
1296         if (rc == 0 && srvlock) {
1297                 struct lu_device *ld    = opg->ops_cl.cpl_obj->co_lu.lo_dev;
1298                 struct osc_stats *stats = &lu2osc_dev(ld)->od_stats;
1299                 int bytes = oap->oap_count;
1300
1301                 if (crt == CRT_READ)
1302                         stats->os_lockless_reads += bytes;
1303                 else
1304                         stats->os_lockless_writes += bytes;
1305         }
1306
1307         /*
1308          * This has to be the last operation with the page, as locks are
1309          * released in cl_page_completion() and nothing except for the
1310          * reference counter protects page from concurrent reclaim.
1311          */
1312         lu_ref_del(&page->cp_reference, "transfer", page);
1313
1314         cl_page_completion(env, page, crt, rc);
1315
1316         RETURN(0);
1317 }
1318
1319 #define OSC_DUMP_GRANT(lvl, cli, fmt, args...) do {                     \
1320         struct client_obd *__tmp = (cli);                               \
1321         CDEBUG(lvl, "%s: grant { dirty: %ld/%ld dirty_pages: %d/%d "    \
1322                "dropped: %ld avail: %ld, reserved: %ld, flight: %d }"   \
1323                "lru {in list: %d, left: %d, waiters: %d }" fmt,         \
1324                __tmp->cl_import->imp_obd->obd_name,                     \
1325                __tmp->cl_dirty, __tmp->cl_dirty_max,                    \
1326                atomic_read(&obd_dirty_pages), obd_max_dirty_pages,      \
1327                __tmp->cl_lost_grant, __tmp->cl_avail_grant,             \
1328                __tmp->cl_reserved_grant, __tmp->cl_w_in_flight,         \
1329                atomic_read(&__tmp->cl_lru_in_list),                     \
1330                atomic_read(&__tmp->cl_lru_busy),                        \
1331                atomic_read(&__tmp->cl_lru_shrinkers), ##args);          \
1332 } while (0)
1333
1334 /* caller must hold loi_list_lock */
1335 static void osc_consume_write_grant(struct client_obd *cli,
1336                                     struct brw_page *pga)
1337 {
1338         assert_spin_locked(&cli->cl_loi_list_lock.lock);
1339         LASSERT(!(pga->flag & OBD_BRW_FROM_GRANT));
1340         atomic_inc(&obd_dirty_pages);
1341         cli->cl_dirty += PAGE_CACHE_SIZE;
1342         pga->flag |= OBD_BRW_FROM_GRANT;
1343         CDEBUG(D_CACHE, "using %lu grant credits for brw %p page %p\n",
1344                PAGE_CACHE_SIZE, pga, pga->pg);
1345         osc_update_next_shrink(cli);
1346 }
1347
1348 /* the companion to osc_consume_write_grant, called when a brw has completed.
1349  * must be called with the loi lock held. */
1350 static void osc_release_write_grant(struct client_obd *cli,
1351                                     struct brw_page *pga)
1352 {
1353         ENTRY;
1354
1355         assert_spin_locked(&cli->cl_loi_list_lock.lock);
1356         if (!(pga->flag & OBD_BRW_FROM_GRANT)) {
1357                 EXIT;
1358                 return;
1359         }
1360
1361         pga->flag &= ~OBD_BRW_FROM_GRANT;
1362         atomic_dec(&obd_dirty_pages);
1363         cli->cl_dirty -= PAGE_CACHE_SIZE;
1364         if (pga->flag & OBD_BRW_NOCACHE) {
1365                 pga->flag &= ~OBD_BRW_NOCACHE;
1366                 atomic_dec(&obd_dirty_transit_pages);
1367                 cli->cl_dirty_transit -= PAGE_CACHE_SIZE;
1368         }
1369         EXIT;
1370 }
1371
1372 /**
1373  * To avoid sleeping with object lock held, it's good for us allocate enough
1374  * grants before entering into critical section.
1375  *
1376  * client_obd_list_lock held by caller
1377  */
1378 static int osc_reserve_grant(struct client_obd *cli, unsigned int bytes)
1379 {
1380         int rc = -EDQUOT;
1381
1382         if (cli->cl_avail_grant >= bytes) {
1383                 cli->cl_avail_grant    -= bytes;
1384                 cli->cl_reserved_grant += bytes;
1385                 rc = 0;
1386         }
1387         return rc;
1388 }
1389
1390 static void __osc_unreserve_grant(struct client_obd *cli,
1391                                   unsigned int reserved, unsigned int unused)
1392 {
1393         /* it's quite normal for us to get more grant than reserved.
1394          * Thinking about a case that two extents merged by adding a new
1395          * chunk, we can save one extent tax. If extent tax is greater than
1396          * one chunk, we can save more grant by adding a new chunk */
1397         cli->cl_reserved_grant -= reserved;
1398         if (unused > reserved) {
1399                 cli->cl_avail_grant += reserved;
1400                 cli->cl_lost_grant  += unused - reserved;
1401         } else {
1402                 cli->cl_avail_grant += unused;
1403         }
1404 }
1405
1406 void osc_unreserve_grant(struct client_obd *cli,
1407                          unsigned int reserved, unsigned int unused)
1408 {
1409         client_obd_list_lock(&cli->cl_loi_list_lock);
1410         __osc_unreserve_grant(cli, reserved, unused);
1411         if (unused > 0)
1412                 osc_wake_cache_waiters(cli);
1413         client_obd_list_unlock(&cli->cl_loi_list_lock);
1414 }
1415
1416 /**
1417  * Free grant after IO is finished or canceled.
1418  *
1419  * @lost_grant is used to remember how many grants we have allocated but not
1420  * used, we should return these grants to OST. There're two cases where grants
1421  * can be lost:
1422  * 1. truncate;
1423  * 2. blocksize at OST is less than PAGE_CACHE_SIZE and a partial page was
1424  *    written. In this case OST may use less chunks to serve this partial
1425  *    write. OSTs don't actually know the page size on the client side. so
1426  *    clients have to calculate lost grant by the blocksize on the OST.
1427  *    See filter_grant_check() for details.
1428  */
1429 static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
1430                            unsigned int lost_grant)
1431 {
1432         int grant = (1 << cli->cl_chunkbits) + cli->cl_extent_tax;
1433
1434         client_obd_list_lock(&cli->cl_loi_list_lock);
1435         atomic_sub(nr_pages, &obd_dirty_pages);
1436         cli->cl_dirty -= nr_pages << PAGE_CACHE_SHIFT;
1437         cli->cl_lost_grant += lost_grant;
1438         if (cli->cl_avail_grant < grant && cli->cl_lost_grant >= grant) {
1439                 /* borrow some grant from truncate to avoid the case that
1440                  * truncate uses up all avail grant */
1441                 cli->cl_lost_grant -= grant;
1442                 cli->cl_avail_grant += grant;
1443         }
1444         osc_wake_cache_waiters(cli);
1445         client_obd_list_unlock(&cli->cl_loi_list_lock);
1446         CDEBUG(D_CACHE, "lost %u grant: %lu avail: %lu dirty: %lu\n",
1447                lost_grant, cli->cl_lost_grant,
1448                cli->cl_avail_grant, cli->cl_dirty);
1449 }
1450
1451 /**
1452  * The companion to osc_enter_cache(), called when @oap is no longer part of
1453  * the dirty accounting due to error.
1454  */
1455 static void osc_exit_cache(struct client_obd *cli, struct osc_async_page *oap)
1456 {
1457         client_obd_list_lock(&cli->cl_loi_list_lock);
1458         osc_release_write_grant(cli, &oap->oap_brw_page);
1459         client_obd_list_unlock(&cli->cl_loi_list_lock);
1460 }
1461
1462 /**
1463  * Non-blocking version of osc_enter_cache() that consumes grant only when it
1464  * is available.
1465  */
1466 static int osc_enter_cache_try(struct client_obd *cli,
1467                                struct osc_async_page *oap,
1468                                int bytes, int transient)
1469 {
1470         int rc;
1471
1472         OSC_DUMP_GRANT(D_CACHE, cli, "need:%d.\n", bytes);
1473
1474         rc = osc_reserve_grant(cli, bytes);
1475         if (rc < 0)
1476                 return 0;
1477
1478         if (cli->cl_dirty + PAGE_CACHE_SIZE <= cli->cl_dirty_max &&
1479             1 + atomic_read(&obd_dirty_pages) <= obd_max_dirty_pages) {
1480                 osc_consume_write_grant(cli, &oap->oap_brw_page);
1481                 if (transient) {
1482                         cli->cl_dirty_transit += PAGE_CACHE_SIZE;
1483                         atomic_inc(&obd_dirty_transit_pages);
1484                         oap->oap_brw_flags |= OBD_BRW_NOCACHE;
1485                 }
1486                 rc = 1;
1487         } else {
1488                 __osc_unreserve_grant(cli, bytes, bytes);
1489                 rc = 0;
1490         }
1491         return rc;
1492 }
1493
1494 static int ocw_granted(struct client_obd *cli, struct osc_cache_waiter *ocw)
1495 {
1496         int rc;
1497         client_obd_list_lock(&cli->cl_loi_list_lock);
1498         rc = list_empty(&ocw->ocw_entry);
1499         client_obd_list_unlock(&cli->cl_loi_list_lock);
1500         return rc;
1501 }
1502
1503 /**
1504  * The main entry to reserve dirty page accounting. Usually the grant reserved
1505  * in this function will be freed in bulk in osc_free_grant() unless it fails
1506  * to add osc cache, in that case, it will be freed in osc_exit_cache().
1507  *
1508  * The process will be put into sleep if it's already run out of grant.
1509  */
1510 static int osc_enter_cache(const struct lu_env *env, struct client_obd *cli,
1511                            struct osc_async_page *oap, int bytes)
1512 {
1513         struct osc_object *osc = oap->oap_obj;
1514         struct lov_oinfo  *loi = osc->oo_oinfo;
1515         struct osc_cache_waiter ocw;
1516         struct l_wait_info lwi = LWI_TIMEOUT_INTR(cfs_time_seconds(600), NULL,
1517                                                   LWI_ON_SIGNAL_NOOP, NULL);
1518         int rc = -EDQUOT;
1519         ENTRY;
1520
1521         OSC_DUMP_GRANT(D_CACHE, cli, "need:%d.\n", bytes);
1522
1523         client_obd_list_lock(&cli->cl_loi_list_lock);
1524
1525         /* force the caller to try sync io.  this can jump the list
1526          * of queued writes and create a discontiguous rpc stream */
1527         if (OBD_FAIL_CHECK(OBD_FAIL_OSC_NO_GRANT) ||
1528             cli->cl_dirty_max < PAGE_CACHE_SIZE     ||
1529             cli->cl_ar.ar_force_sync || loi->loi_ar.ar_force_sync)
1530                 GOTO(out, rc = -EDQUOT);
1531
1532         /* Hopefully normal case - cache space and write credits available */
1533         if (osc_enter_cache_try(cli, oap, bytes, 0))
1534                 GOTO(out, rc = 0);
1535
1536         /* We can get here for two reasons: too many dirty pages in cache, or
1537          * run out of grants. In both cases we should write dirty pages out.
1538          * Adding a cache waiter will trigger urgent write-out no matter what
1539          * RPC size will be.
1540          * The exiting condition is no avail grants and no dirty pages caching,
1541          * that really means there is no space on the OST. */
1542         init_waitqueue_head(&ocw.ocw_waitq);
1543         ocw.ocw_oap   = oap;
1544         ocw.ocw_grant = bytes;
1545         while (cli->cl_dirty > 0 || cli->cl_w_in_flight > 0) {
1546                 list_add_tail(&ocw.ocw_entry, &cli->cl_cache_waiters);
1547                 ocw.ocw_rc = 0;
1548                 client_obd_list_unlock(&cli->cl_loi_list_lock);
1549
1550                 osc_io_unplug_async(env, cli, NULL);
1551
1552                 CDEBUG(D_CACHE, "%s: sleeping for cache space @ %p for %p\n",
1553                        cli->cl_import->imp_obd->obd_name, &ocw, oap);
1554
1555                 rc = l_wait_event(ocw.ocw_waitq, ocw_granted(cli, &ocw), &lwi);
1556
1557                 client_obd_list_lock(&cli->cl_loi_list_lock);
1558
1559                 /* l_wait_event is interrupted by signal, or timed out */
1560                 if (rc < 0) {
1561                         switch (rc) {
1562                         case -ETIMEDOUT:
1563                                 OSC_DUMP_GRANT(D_ERROR, cli,
1564                                                 "try to reserve %d.\n", bytes);
1565                                 osc_extent_tree_dump(D_ERROR, osc);
1566                                 rc = -EDQUOT;
1567                                 break;
1568                         case -EINTR:
1569                                 /* Ensures restartability - LU-3581 */
1570                                 rc = -ERESTARTSYS;
1571                                 break;
1572                         default:
1573                                 CDEBUG(D_CACHE, "%s: event for cache space @"
1574                                        " %p never arrived due to %d\n",
1575                                        cli->cl_import->imp_obd->obd_name,
1576                                        &ocw, rc);
1577                                 break;
1578                         }
1579                         list_del_init(&ocw.ocw_entry);
1580                         GOTO(out, rc);
1581                 }
1582
1583                 LASSERT(list_empty(&ocw.ocw_entry));
1584                 rc = ocw.ocw_rc;
1585
1586                 if (rc != -EDQUOT)
1587                         GOTO(out, rc);
1588                 if (osc_enter_cache_try(cli, oap, bytes, 0))
1589                         GOTO(out, rc = 0);
1590         }
1591         EXIT;
1592 out:
1593         client_obd_list_unlock(&cli->cl_loi_list_lock);
1594         OSC_DUMP_GRANT(D_CACHE, cli, "returned %d.\n", rc);
1595         RETURN(rc);
1596 }
1597
1598 /* caller must hold loi_list_lock */
1599 void osc_wake_cache_waiters(struct client_obd *cli)
1600 {
1601         struct list_head *l, *tmp;
1602         struct osc_cache_waiter *ocw;
1603
1604         ENTRY;
1605         list_for_each_safe(l, tmp, &cli->cl_cache_waiters) {
1606                 ocw = list_entry(l, struct osc_cache_waiter, ocw_entry);
1607                 list_del_init(&ocw->ocw_entry);
1608
1609                 ocw->ocw_rc = -EDQUOT;
1610                 /* we can't dirty more */
1611                 if ((cli->cl_dirty + PAGE_CACHE_SIZE > cli->cl_dirty_max) ||
1612                     (1 + atomic_read(&obd_dirty_pages) > obd_max_dirty_pages)) {
1613                         CDEBUG(D_CACHE, "no dirty room: dirty: %ld "
1614                                "osc max %ld, sys max %d\n", cli->cl_dirty,
1615                                cli->cl_dirty_max, obd_max_dirty_pages);
1616                         goto wakeup;
1617                 }
1618
1619                 ocw->ocw_rc = 0;
1620                 if (!osc_enter_cache_try(cli, ocw->ocw_oap, ocw->ocw_grant, 0))
1621                         ocw->ocw_rc = -EDQUOT;
1622
1623 wakeup:
1624                 CDEBUG(D_CACHE, "wake up %p for oap %p, avail grant %ld, %d\n",
1625                        ocw, ocw->ocw_oap, cli->cl_avail_grant, ocw->ocw_rc);
1626
1627                 wake_up(&ocw->ocw_waitq);
1628         }
1629
1630         EXIT;
1631 }
1632
1633 static int osc_max_rpc_in_flight(struct client_obd *cli, struct osc_object *osc)
1634 {
1635         int hprpc = !!list_empty(&osc->oo_hp_exts);
1636         return rpcs_in_flight(cli) >= cli->cl_max_rpcs_in_flight + hprpc;
1637 }
1638
1639 /* This maintains the lists of pending pages to read/write for a given object
1640  * (lop).  This is used by osc_check_rpcs->osc_next_obj() and osc_list_maint()
1641  * to quickly find objects that are ready to send an RPC. */
1642 static int osc_makes_rpc(struct client_obd *cli, struct osc_object *osc,
1643                          int cmd)
1644 {
1645         int invalid_import = 0;
1646         ENTRY;
1647
1648         /* if we have an invalid import we want to drain the queued pages
1649          * by forcing them through rpcs that immediately fail and complete
1650          * the pages.  recovery relies on this to empty the queued pages
1651          * before canceling the locks and evicting down the llite pages */
1652         if ((cli->cl_import == NULL || cli->cl_import->imp_invalid))
1653                 invalid_import = 1;
1654
1655         if (cmd & OBD_BRW_WRITE) {
1656                 if (atomic_read(&osc->oo_nr_writes) == 0)
1657                         RETURN(0);
1658                 if (invalid_import) {
1659                         CDEBUG(D_CACHE, "invalid import forcing RPC\n");
1660                         RETURN(1);
1661                 }
1662                 if (!list_empty(&osc->oo_hp_exts)) {
1663                         CDEBUG(D_CACHE, "high prio request forcing RPC\n");
1664                         RETURN(1);
1665                 }
1666                 if (!list_empty(&osc->oo_urgent_exts)) {
1667                         CDEBUG(D_CACHE, "urgent request forcing RPC\n");
1668                         RETURN(1);
1669                 }
1670                 /* trigger a write rpc stream as long as there are dirtiers
1671                  * waiting for space.  as they're waiting, they're not going to
1672                  * create more pages to coalesce with what's waiting.. */
1673                 if (!list_empty(&cli->cl_cache_waiters)) {
1674                         CDEBUG(D_CACHE, "cache waiters forcing RPC\n");
1675                         RETURN(1);
1676                 }
1677                 if (atomic_read(&osc->oo_nr_writes) >=
1678                     cli->cl_max_pages_per_rpc)
1679                         RETURN(1);
1680         } else {
1681                 if (atomic_read(&osc->oo_nr_reads) == 0)
1682                         RETURN(0);
1683                 if (invalid_import) {
1684                         CDEBUG(D_CACHE, "invalid import forcing RPC\n");
1685                         RETURN(1);
1686                 }
1687                 /* all read are urgent. */
1688                 if (!list_empty(&osc->oo_reading_exts))
1689                         RETURN(1);
1690         }
1691
1692         RETURN(0);
1693 }
1694
1695 static void osc_update_pending(struct osc_object *obj, int cmd, int delta)
1696 {
1697         struct client_obd *cli = osc_cli(obj);
1698         if (cmd & OBD_BRW_WRITE) {
1699                 atomic_add(delta, &obj->oo_nr_writes);
1700                 atomic_add(delta, &cli->cl_pending_w_pages);
1701                 LASSERT(atomic_read(&obj->oo_nr_writes) >= 0);
1702         } else {
1703                 atomic_add(delta, &obj->oo_nr_reads);
1704                 atomic_add(delta, &cli->cl_pending_r_pages);
1705                 LASSERT(atomic_read(&obj->oo_nr_reads) >= 0);
1706         }
1707         OSC_IO_DEBUG(obj, "update pending cmd %d delta %d.\n", cmd, delta);
1708 }
1709
1710 static int osc_makes_hprpc(struct osc_object *obj)
1711 {
1712         return !list_empty(&obj->oo_hp_exts);
1713 }
1714
1715 static void on_list(struct list_head *item, struct list_head *list,
1716                     int should_be_on)
1717 {
1718         if (list_empty(item) && should_be_on)
1719                 list_add_tail(item, list);
1720         else if (!list_empty(item) && !should_be_on)
1721                 list_del_init(item);
1722 }
1723
1724 /* maintain the osc's cli list membership invariants so that osc_send_oap_rpc
1725  * can find pages to build into rpcs quickly */
1726 static int __osc_list_maint(struct client_obd *cli, struct osc_object *osc)
1727 {
1728         if (osc_makes_hprpc(osc)) {
1729                 /* HP rpc */
1730                 on_list(&osc->oo_ready_item, &cli->cl_loi_ready_list, 0);
1731                 on_list(&osc->oo_hp_ready_item, &cli->cl_loi_hp_ready_list, 1);
1732         } else {
1733                 on_list(&osc->oo_hp_ready_item, &cli->cl_loi_hp_ready_list, 0);
1734                 on_list(&osc->oo_ready_item, &cli->cl_loi_ready_list,
1735                         osc_makes_rpc(cli, osc, OBD_BRW_WRITE) ||
1736                         osc_makes_rpc(cli, osc, OBD_BRW_READ));
1737         }
1738
1739         on_list(&osc->oo_write_item, &cli->cl_loi_write_list,
1740                 atomic_read(&osc->oo_nr_writes) > 0);
1741
1742         on_list(&osc->oo_read_item, &cli->cl_loi_read_list,
1743                 atomic_read(&osc->oo_nr_reads) > 0);
1744
1745         return osc_is_ready(osc);
1746 }
1747
1748 static int osc_list_maint(struct client_obd *cli, struct osc_object *osc)
1749 {
1750         int is_ready;
1751
1752         client_obd_list_lock(&cli->cl_loi_list_lock);
1753         is_ready = __osc_list_maint(cli, osc);
1754         client_obd_list_unlock(&cli->cl_loi_list_lock);
1755
1756         return is_ready;
1757 }
1758
1759 /* this is trying to propogate async writeback errors back up to the
1760  * application.  As an async write fails we record the error code for later if
1761  * the app does an fsync.  As long as errors persist we force future rpcs to be
1762  * sync so that the app can get a sync error and break the cycle of queueing
1763  * pages for which writeback will fail. */
1764 static void osc_process_ar(struct osc_async_rc *ar, __u64 xid,
1765                            int rc)
1766 {
1767         if (rc) {
1768                 if (!ar->ar_rc)
1769                         ar->ar_rc = rc;
1770
1771                 ar->ar_force_sync = 1;
1772                 ar->ar_min_xid = ptlrpc_sample_next_xid();
1773                 return;
1774
1775         }
1776
1777         if (ar->ar_force_sync && (xid >= ar->ar_min_xid))
1778                 ar->ar_force_sync = 0;
1779 }
1780
1781 /* this must be called holding the loi list lock to give coverage to exit_cache,
1782  * async_flag maintenance, and oap_request */
1783 static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
1784                               struct osc_async_page *oap, int sent, int rc)
1785 {
1786         struct osc_object *osc = oap->oap_obj;
1787         struct lov_oinfo  *loi = osc->oo_oinfo;
1788         __u64 xid = 0;
1789
1790         ENTRY;
1791         if (oap->oap_request != NULL) {
1792                 xid = ptlrpc_req_xid(oap->oap_request);
1793                 ptlrpc_req_finished(oap->oap_request);
1794                 oap->oap_request = NULL;
1795         }
1796
1797         /* As the transfer for this page is being done, clear the flags */
1798         spin_lock(&oap->oap_lock);
1799         oap->oap_async_flags = 0;
1800         spin_unlock(&oap->oap_lock);
1801         oap->oap_interrupted = 0;
1802
1803         if (oap->oap_cmd & OBD_BRW_WRITE && xid > 0) {
1804                 client_obd_list_lock(&cli->cl_loi_list_lock);
1805                 osc_process_ar(&cli->cl_ar, xid, rc);
1806                 osc_process_ar(&loi->loi_ar, xid, rc);
1807                 client_obd_list_unlock(&cli->cl_loi_list_lock);
1808         }
1809
1810         rc = osc_completion(env, oap, oap->oap_cmd, rc);
1811         if (rc)
1812                 CERROR("completion on oap %p obj %p returns %d.\n",
1813                        oap, osc, rc);
1814
1815         EXIT;
1816 }
1817
1818 /**
1819  * Try to add extent to one RPC. We need to think about the following things:
1820  * - # of pages must not be over max_pages_per_rpc
1821  * - extent must be compatible with previous ones
1822  */
1823 static int try_to_add_extent_for_io(struct client_obd *cli,
1824                                     struct osc_extent *ext,
1825                                     struct list_head *rpclist,
1826                                     int *pc, unsigned int *max_pages)
1827 {
1828         struct osc_extent *tmp;
1829         ENTRY;
1830
1831         EASSERT((ext->oe_state == OES_CACHE || ext->oe_state == OES_LOCK_DONE),
1832                 ext);
1833
1834         *max_pages = max(ext->oe_mppr, *max_pages);
1835         if (*pc + ext->oe_nr_pages > *max_pages)
1836                 RETURN(0);
1837
1838         list_for_each_entry(tmp, rpclist, oe_link) {
1839                 EASSERT(tmp->oe_owner == current, tmp);
1840 #if 0
1841                 if (overlapped(tmp, ext)) {
1842                         OSC_EXTENT_DUMP(D_ERROR, tmp, "overlapped %p.\n", ext);
1843                         EASSERT(0, ext);
1844                 }
1845 #endif
1846
1847                 if (tmp->oe_srvlock != ext->oe_srvlock ||
1848                     !tmp->oe_grants != !ext->oe_grants)
1849                         RETURN(0);
1850
1851                 /* remove break for strict check */
1852                 break;
1853         }
1854
1855         *pc += ext->oe_nr_pages;
1856         list_move_tail(&ext->oe_link, rpclist);
1857         ext->oe_owner = current;
1858         RETURN(1);
1859 }
1860
1861 /**
1862  * In order to prevent multiple ptlrpcd from breaking contiguous extents,
1863  * get_write_extent() takes all appropriate extents in atomic.
1864  *
1865  * The following policy is used to collect extents for IO:
1866  * 1. Add as many HP extents as possible;
1867  * 2. Add the first urgent extent in urgent extent list and take it out of
1868  *    urgent list;
1869  * 3. Add subsequent extents of this urgent extent;
1870  * 4. If urgent list is not empty, goto 2;
1871  * 5. Traverse the extent tree from the 1st extent;
1872  * 6. Above steps exit if there is no space in this RPC.
1873  */
1874 static int get_write_extents(struct osc_object *obj, struct list_head *rpclist)
1875 {
1876         struct client_obd *cli = osc_cli(obj);
1877         struct osc_extent *ext;
1878         int page_count = 0;
1879         unsigned int max_pages = cli->cl_max_pages_per_rpc;
1880
1881         LASSERT(osc_object_is_locked(obj));
1882         while (!list_empty(&obj->oo_hp_exts)) {
1883                 ext = list_entry(obj->oo_hp_exts.next, struct osc_extent,
1884                                  oe_link);
1885                 LASSERT(ext->oe_state == OES_CACHE);
1886                 if (!try_to_add_extent_for_io(cli, ext, rpclist, &page_count,
1887                                               &max_pages))
1888                         return page_count;
1889                 EASSERT(ext->oe_nr_pages <= max_pages, ext);
1890         }
1891         if (page_count == max_pages)
1892                 return page_count;
1893
1894         while (!list_empty(&obj->oo_urgent_exts)) {
1895                 ext = list_entry(obj->oo_urgent_exts.next,
1896                                  struct osc_extent, oe_link);
1897                 if (!try_to_add_extent_for_io(cli, ext, rpclist, &page_count,
1898                                               &max_pages))
1899                         return page_count;
1900
1901                 if (!ext->oe_intree)
1902                         continue;
1903
1904                 while ((ext = next_extent(ext)) != NULL) {
1905                         if ((ext->oe_state != OES_CACHE) ||
1906                             (!list_empty(&ext->oe_link) &&
1907                              ext->oe_owner != NULL))
1908                                 continue;
1909
1910                         if (!try_to_add_extent_for_io(cli, ext, rpclist,
1911                                                       &page_count, &max_pages))
1912                                 return page_count;
1913                 }
1914         }
1915         if (page_count == max_pages)
1916                 return page_count;
1917
1918         ext = first_extent(obj);
1919         while (ext != NULL) {
1920                 if ((ext->oe_state != OES_CACHE) ||
1921                     /* this extent may be already in current rpclist */
1922                     (!list_empty(&ext->oe_link) && ext->oe_owner != NULL)) {
1923                         ext = next_extent(ext);
1924                         continue;
1925                 }
1926
1927                 if (!try_to_add_extent_for_io(cli, ext, rpclist, &page_count,
1928                                               &max_pages))
1929                         return page_count;
1930
1931                 ext = next_extent(ext);
1932         }
1933         return page_count;
1934 }
1935
1936 static int
1937 osc_send_write_rpc(const struct lu_env *env, struct client_obd *cli,
1938                    struct osc_object *osc, pdl_policy_t pol)
1939 {
1940         struct list_head   rpclist = LIST_HEAD_INIT(rpclist);
1941         struct osc_extent *ext;
1942         struct osc_extent *tmp;
1943         struct osc_extent *first = NULL;
1944         obd_count page_count = 0;
1945         int srvlock = 0;
1946         int rc = 0;
1947         ENTRY;
1948
1949         LASSERT(osc_object_is_locked(osc));
1950
1951         page_count = get_write_extents(osc, &rpclist);
1952         LASSERT(equi(page_count == 0, list_empty(&rpclist)));
1953
1954         if (list_empty(&rpclist))
1955                 RETURN(0);
1956
1957         osc_update_pending(osc, OBD_BRW_WRITE, -page_count);
1958
1959         list_for_each_entry(ext, &rpclist, oe_link) {
1960                 LASSERT(ext->oe_state == OES_CACHE ||
1961                         ext->oe_state == OES_LOCK_DONE);
1962                 if (ext->oe_state == OES_CACHE)
1963                         osc_extent_state_set(ext, OES_LOCKING);
1964                 else
1965                         osc_extent_state_set(ext, OES_RPC);
1966         }
1967
1968         /* we're going to grab page lock, so release object lock because
1969          * lock order is page lock -> object lock. */
1970         osc_object_unlock(osc);
1971
1972         list_for_each_entry_safe(ext, tmp, &rpclist, oe_link) {
1973                 if (ext->oe_state == OES_LOCKING) {
1974                         rc = osc_extent_make_ready(env, ext);
1975                         if (unlikely(rc < 0)) {
1976                                 list_del_init(&ext->oe_link);
1977                                 osc_extent_finish(env, ext, 0, rc);
1978                                 continue;
1979                         }
1980                 }
1981                 if (first == NULL) {
1982                         first = ext;
1983                         srvlock = ext->oe_srvlock;
1984                 } else {
1985                         LASSERT(srvlock == ext->oe_srvlock);
1986                 }
1987         }
1988
1989         if (!list_empty(&rpclist)) {
1990                 LASSERT(page_count > 0);
1991                 rc = osc_build_rpc(env, cli, &rpclist, OBD_BRW_WRITE, pol);
1992                 LASSERT(list_empty(&rpclist));
1993         }
1994
1995         osc_object_lock(osc);
1996         RETURN(rc);
1997 }
1998
1999 /**
2000  * prepare pages for ASYNC io and put pages in send queue.
2001  *
2002  * \param cmd OBD_BRW_* macroses
2003  * \param lop pending pages
2004  *
2005  * \return zero if no page added to send queue.
2006  * \return 1 if pages successfully added to send queue.
2007  * \return negative on errors.
2008  */
2009 static int
2010 osc_send_read_rpc(const struct lu_env *env, struct client_obd *cli,
2011                   struct osc_object *osc, pdl_policy_t pol)
2012 {
2013         struct osc_extent *ext;
2014         struct osc_extent *next;
2015         struct list_head rpclist = LIST_HEAD_INIT(rpclist);
2016         int page_count = 0;
2017         unsigned int max_pages = cli->cl_max_pages_per_rpc;
2018         int rc = 0;
2019         ENTRY;
2020
2021         LASSERT(osc_object_is_locked(osc));
2022         list_for_each_entry_safe(ext, next,
2023                                      &osc->oo_reading_exts, oe_link) {
2024                 EASSERT(ext->oe_state == OES_LOCK_DONE, ext);
2025                 if (!try_to_add_extent_for_io(cli, ext, &rpclist, &page_count,
2026                                               &max_pages))
2027                         break;
2028                 osc_extent_state_set(ext, OES_RPC);
2029                 EASSERT(ext->oe_nr_pages <= max_pages, ext);
2030         }
2031         LASSERT(page_count <= max_pages);
2032
2033         osc_update_pending(osc, OBD_BRW_READ, -page_count);
2034
2035         if (!list_empty(&rpclist)) {
2036                 osc_object_unlock(osc);
2037
2038                 LASSERT(page_count > 0);
2039                 rc = osc_build_rpc(env, cli, &rpclist, OBD_BRW_READ, pol);
2040                 LASSERT(list_empty(&rpclist));
2041
2042                 osc_object_lock(osc);
2043         }
2044         RETURN(rc);
2045 }
2046
2047 #define list_to_obj(list, item) ({                                            \
2048         struct list_head *__tmp = (list)->next;                               \
2049         list_del_init(__tmp);                                         \
2050         list_entry(__tmp, struct osc_object, oo_##item);                      \
2051 })
2052
2053 /* This is called by osc_check_rpcs() to find which objects have pages that
2054  * we could be sending.  These lists are maintained by osc_makes_rpc(). */
2055 static struct osc_object *osc_next_obj(struct client_obd *cli)
2056 {
2057         ENTRY;
2058
2059         /* First return objects that have blocked locks so that they
2060          * will be flushed quickly and other clients can get the lock,
2061          * then objects which have pages ready to be stuffed into RPCs */
2062         if (!list_empty(&cli->cl_loi_hp_ready_list))
2063                 RETURN(list_to_obj(&cli->cl_loi_hp_ready_list, hp_ready_item));
2064         if (!list_empty(&cli->cl_loi_ready_list))
2065                 RETURN(list_to_obj(&cli->cl_loi_ready_list, ready_item));
2066
2067         /* then if we have cache waiters, return all objects with queued
2068          * writes.  This is especially important when many small files
2069          * have filled up the cache and not been fired into rpcs because
2070          * they don't pass the nr_pending/object threshhold */
2071         if (!list_empty(&cli->cl_cache_waiters) &&
2072             !list_empty(&cli->cl_loi_write_list))
2073                 RETURN(list_to_obj(&cli->cl_loi_write_list, write_item));
2074
2075         /* then return all queued objects when we have an invalid import
2076          * so that they get flushed */
2077         if (cli->cl_import == NULL || cli->cl_import->imp_invalid) {
2078                 if (!list_empty(&cli->cl_loi_write_list))
2079                         RETURN(list_to_obj(&cli->cl_loi_write_list,
2080                                            write_item));
2081                 if (!list_empty(&cli->cl_loi_read_list))
2082                         RETURN(list_to_obj(&cli->cl_loi_read_list,
2083                                            read_item));
2084         }
2085         RETURN(NULL);
2086 }
2087
2088 /* called with the loi list lock held */
2089 static void osc_check_rpcs(const struct lu_env *env, struct client_obd *cli,
2090                            pdl_policy_t pol)
2091 {
2092         struct osc_object *osc;
2093         int rc = 0;
2094         ENTRY;
2095
2096         while ((osc = osc_next_obj(cli)) != NULL) {
2097                 struct cl_object *obj = osc2cl(osc);
2098                 struct lu_ref_link link;
2099
2100                 OSC_IO_DEBUG(osc, "%lu in flight\n", rpcs_in_flight(cli));
2101
2102                 if (osc_max_rpc_in_flight(cli, osc)) {
2103                         __osc_list_maint(cli, osc);
2104                         break;
2105                 }
2106
2107                 cl_object_get(obj);
2108                 client_obd_list_unlock(&cli->cl_loi_list_lock);
2109                 lu_object_ref_add_at(&obj->co_lu, &link, "check", current);
2110
2111                 /* attempt some read/write balancing by alternating between
2112                  * reads and writes in an object.  The makes_rpc checks here
2113                  * would be redundant if we were getting read/write work items
2114                  * instead of objects.  we don't want send_oap_rpc to drain a
2115                  * partial read pending queue when we're given this object to
2116                  * do io on writes while there are cache waiters */
2117                 osc_object_lock(osc);
2118                 if (osc_makes_rpc(cli, osc, OBD_BRW_WRITE)) {
2119                         rc = osc_send_write_rpc(env, cli, osc, pol);
2120                         if (rc < 0) {
2121                                 CERROR("Write request failed with %d\n", rc);
2122
2123                                 /* osc_send_write_rpc failed, mostly because of
2124                                  * memory pressure.
2125                                  *
2126                                  * It can't break here, because if:
2127                                  *  - a page was submitted by osc_io_submit, so
2128                                  *    page locked;
2129                                  *  - no request in flight
2130                                  *  - no subsequent request
2131                                  * The system will be in live-lock state,
2132                                  * because there is no chance to call
2133                                  * osc_io_unplug() and osc_check_rpcs() any
2134                                  * more. pdflush can't help in this case,
2135                                  * because it might be blocked at grabbing
2136                                  * the page lock as we mentioned.
2137                                  *
2138                                  * Anyway, continue to drain pages. */
2139                                 /* break; */
2140                         }
2141                 }
2142                 if (osc_makes_rpc(cli, osc, OBD_BRW_READ)) {
2143                         rc = osc_send_read_rpc(env, cli, osc, pol);
2144                         if (rc < 0)
2145                                 CERROR("Read request failed with %d\n", rc);
2146                 }
2147                 osc_object_unlock(osc);
2148
2149                 osc_list_maint(cli, osc);
2150                 lu_object_ref_del_at(&obj->co_lu, &link, "check", current);
2151                 cl_object_put(env, obj);
2152
2153                 client_obd_list_lock(&cli->cl_loi_list_lock);
2154         }
2155 }
2156
2157 static int osc_io_unplug0(const struct lu_env *env, struct client_obd *cli,
2158                           struct osc_object *osc, pdl_policy_t pol, int async)
2159 {
2160         int rc = 0;
2161
2162         if (osc != NULL && osc_list_maint(cli, osc) == 0)
2163                 return 0;
2164
2165         if (!async) {
2166                 /* disable osc_lru_shrink() temporarily to avoid
2167                  * potential stack overrun problem. LU-2859 */
2168                 atomic_inc(&cli->cl_lru_shrinkers);
2169                 client_obd_list_lock(&cli->cl_loi_list_lock);
2170                 osc_check_rpcs(env, cli, pol);
2171                 client_obd_list_unlock(&cli->cl_loi_list_lock);
2172                 atomic_dec(&cli->cl_lru_shrinkers);
2173         } else {
2174                 CDEBUG(D_CACHE, "Queue writeback work for client %p.\n", cli);
2175                 LASSERT(cli->cl_writeback_work != NULL);
2176                 rc = ptlrpcd_queue_work(cli->cl_writeback_work);
2177         }
2178         return rc;
2179 }
2180
2181 static int osc_io_unplug_async(const struct lu_env *env,
2182                                 struct client_obd *cli, struct osc_object *osc)
2183 {
2184         /* XXX: policy is no use actually. */
2185         return osc_io_unplug0(env, cli, osc, PDL_POLICY_ROUND, 1);
2186 }
2187
2188 void osc_io_unplug(const struct lu_env *env, struct client_obd *cli,
2189                    struct osc_object *osc, pdl_policy_t pol)
2190 {
2191         (void)osc_io_unplug0(env, cli, osc, pol, 0);
2192 }
2193
2194 int osc_prep_async_page(struct osc_object *osc, struct osc_page *ops,
2195                         struct page *page, loff_t offset)
2196 {
2197         struct obd_export     *exp = osc_export(osc);
2198         struct osc_async_page *oap = &ops->ops_oap;
2199         ENTRY;
2200
2201         if (!page)
2202                 return cfs_size_round(sizeof(*oap));
2203
2204         oap->oap_magic = OAP_MAGIC;
2205         oap->oap_cli = &exp->exp_obd->u.cli;
2206         oap->oap_obj = osc;
2207
2208         oap->oap_page = page;
2209         oap->oap_obj_off = offset;
2210         LASSERT(!(offset & ~CFS_PAGE_MASK));
2211
2212         if (!client_is_remote(exp) && cfs_capable(CFS_CAP_SYS_RESOURCE))
2213                 oap->oap_brw_flags = OBD_BRW_NOQUOTA;
2214
2215         INIT_LIST_HEAD(&oap->oap_pending_item);
2216         INIT_LIST_HEAD(&oap->oap_rpc_item);
2217
2218         spin_lock_init(&oap->oap_lock);
2219         CDEBUG(D_INFO, "oap %p page %p obj off "LPU64"\n",
2220                oap, page, oap->oap_obj_off);
2221         RETURN(0);
2222 }
2223
2224 int osc_queue_async_io(const struct lu_env *env, struct cl_io *io,
2225                        struct osc_page *ops)
2226 {
2227         struct osc_io *oio = osc_env_io(env);
2228         struct osc_extent     *ext = NULL;
2229         struct osc_async_page *oap = &ops->ops_oap;
2230         struct client_obd     *cli = oap->oap_cli;
2231         struct osc_object     *osc = oap->oap_obj;
2232         pgoff_t index;
2233         int    grants = 0;
2234         int    brw_flags = OBD_BRW_ASYNC;
2235         int    cmd = OBD_BRW_WRITE;
2236         int    need_release = 0;
2237         int    rc = 0;
2238         ENTRY;
2239
2240         if (oap->oap_magic != OAP_MAGIC)
2241                 RETURN(-EINVAL);
2242
2243         if (cli->cl_import == NULL || cli->cl_import->imp_invalid)
2244                 RETURN(-EIO);
2245
2246         if (!list_empty(&oap->oap_pending_item) ||
2247             !list_empty(&oap->oap_rpc_item))
2248                 RETURN(-EBUSY);
2249
2250         /* Set the OBD_BRW_SRVLOCK before the page is queued. */
2251         brw_flags |= ops->ops_srvlock ? OBD_BRW_SRVLOCK : 0;
2252         if (!client_is_remote(osc_export(osc)) &&
2253             cfs_capable(CFS_CAP_SYS_RESOURCE)) {
2254                 brw_flags |= OBD_BRW_NOQUOTA;
2255                 cmd |= OBD_BRW_NOQUOTA;
2256         }
2257
2258         /* check if the file's owner/group is over quota */
2259         if (!(cmd & OBD_BRW_NOQUOTA)) {
2260                 struct cl_object *obj;
2261                 struct cl_attr   *attr;
2262                 unsigned int qid[MAXQUOTAS];
2263
2264                 obj = cl_object_top(&osc->oo_cl);
2265                 attr = &osc_env_info(env)->oti_attr;
2266
2267                 cl_object_attr_lock(obj);
2268                 rc = cl_object_attr_get(env, obj, attr);
2269                 cl_object_attr_unlock(obj);
2270
2271                 qid[USRQUOTA] = attr->cat_uid;
2272                 qid[GRPQUOTA] = attr->cat_gid;
2273                 if (rc == 0 && osc_quota_chkdq(cli, qid) == NO_QUOTA)
2274                         rc = -EDQUOT;
2275                 if (rc)
2276                         RETURN(rc);
2277         }
2278
2279         oap->oap_cmd = cmd;
2280         oap->oap_page_off = ops->ops_from;
2281         oap->oap_count = ops->ops_to - ops->ops_from;
2282         /* No need to hold a lock here,
2283          * since this page is not in any list yet. */
2284         oap->oap_async_flags = 0;
2285         oap->oap_brw_flags = brw_flags;
2286
2287         OSC_IO_DEBUG(osc, "oap %p page %p added for cmd %d\n",
2288                      oap, oap->oap_page, oap->oap_cmd & OBD_BRW_RWMASK);
2289
2290         index = osc_index(oap2osc(oap));
2291
2292         /* Add this page into extent by the following steps:
2293          * 1. if there exists an active extent for this IO, mostly this page
2294          *    can be added to the active extent and sometimes we need to
2295          *    expand extent to accomodate this page;
2296          * 2. otherwise, a new extent will be allocated. */
2297
2298         ext = oio->oi_active;
2299         if (ext != NULL && ext->oe_start <= index && ext->oe_max_end >= index) {
2300                 /* one chunk plus extent overhead must be enough to write this
2301                  * page */
2302                 grants = (1 << cli->cl_chunkbits) + cli->cl_extent_tax;
2303                 if (ext->oe_end >= index)
2304                         grants = 0;
2305
2306                 /* it doesn't need any grant to dirty this page */
2307                 client_obd_list_lock(&cli->cl_loi_list_lock);
2308                 rc = osc_enter_cache_try(cli, oap, grants, 0);
2309                 client_obd_list_unlock(&cli->cl_loi_list_lock);
2310                 if (rc == 0) { /* try failed */
2311                         grants = 0;
2312                         need_release = 1;
2313                 } else if (ext->oe_end < index) {
2314                         int tmp = grants;
2315                         /* try to expand this extent */
2316                         rc = osc_extent_expand(ext, index, &tmp);
2317                         if (rc < 0) {
2318                                 need_release = 1;
2319                                 /* don't free reserved grant */
2320                         } else {
2321                                 OSC_EXTENT_DUMP(D_CACHE, ext,
2322                                                 "expanded for %lu.\n", index);
2323                                 osc_unreserve_grant(cli, grants, tmp);
2324                                 grants = 0;
2325                         }
2326                 }
2327                 rc = 0;
2328         } else if (ext != NULL) {
2329                 /* index is located outside of active extent */
2330                 need_release = 1;
2331         }
2332         if (need_release) {
2333                 osc_extent_release(env, ext);
2334                 oio->oi_active = NULL;
2335                 ext = NULL;
2336         }
2337
2338         if (ext == NULL) {
2339                 int tmp = (1 << cli->cl_chunkbits) + cli->cl_extent_tax;
2340
2341                 /* try to find new extent to cover this page */
2342                 LASSERT(oio->oi_active == NULL);
2343                 /* we may have allocated grant for this page if we failed
2344                  * to expand the previous active extent. */
2345                 LASSERT(ergo(grants > 0, grants >= tmp));
2346
2347                 rc = 0;
2348                 if (grants == 0) {
2349                         /* we haven't allocated grant for this page. */
2350                         rc = osc_enter_cache(env, cli, oap, tmp);
2351                         if (rc == 0)
2352                                 grants = tmp;
2353                 }
2354
2355                 tmp = grants;
2356                 if (rc == 0) {
2357                         ext = osc_extent_find(env, osc, index, &tmp);
2358                         if (IS_ERR(ext)) {
2359                                 LASSERT(tmp == grants);
2360                                 osc_exit_cache(cli, oap);
2361                                 rc = PTR_ERR(ext);
2362                                 ext = NULL;
2363                         } else {
2364                                 oio->oi_active = ext;
2365                         }
2366                 }
2367                 if (grants > 0)
2368                         osc_unreserve_grant(cli, grants, tmp);
2369         }
2370
2371         LASSERT(ergo(rc == 0, ext != NULL));
2372         if (ext != NULL) {
2373                 EASSERTF(ext->oe_end >= index && ext->oe_start <= index,
2374                          ext, "index = %lu.\n", index);
2375                 LASSERT((oap->oap_brw_flags & OBD_BRW_FROM_GRANT) != 0);
2376
2377                 osc_object_lock(osc);
2378                 if (ext->oe_nr_pages == 0)
2379                         ext->oe_srvlock = ops->ops_srvlock;
2380                 else
2381                         LASSERT(ext->oe_srvlock == ops->ops_srvlock);
2382                 ++ext->oe_nr_pages;
2383                 list_add_tail(&oap->oap_pending_item, &ext->oe_pages);
2384                 osc_object_unlock(osc);
2385         }
2386         RETURN(rc);
2387 }
2388
2389 int osc_teardown_async_page(const struct lu_env *env,
2390                             struct osc_object *obj, struct osc_page *ops)
2391 {
2392         struct osc_async_page *oap = &ops->ops_oap;
2393         struct osc_extent     *ext = NULL;
2394         int rc = 0;
2395         ENTRY;
2396
2397         LASSERT(oap->oap_magic == OAP_MAGIC);
2398
2399         CDEBUG(D_INFO, "teardown oap %p page %p at index %lu.\n",
2400                oap, ops, osc_index(oap2osc(oap)));
2401
2402         osc_object_lock(obj);
2403         if (!list_empty(&oap->oap_rpc_item)) {
2404                 CDEBUG(D_CACHE, "oap %p is not in cache.\n", oap);
2405                 rc = -EBUSY;
2406         } else if (!list_empty(&oap->oap_pending_item)) {
2407                 ext = osc_extent_lookup(obj, osc_index(oap2osc(oap)));
2408                 /* only truncated pages are allowed to be taken out.
2409                  * See osc_extent_truncate() and osc_cache_truncate_start()
2410                  * for details. */
2411                 if (ext != NULL && ext->oe_state != OES_TRUNC) {
2412                         OSC_EXTENT_DUMP(D_ERROR, ext, "trunc at %lu.\n",
2413                                         osc_index(oap2osc(oap)));
2414                         rc = -EBUSY;
2415                 }
2416         }
2417         osc_object_unlock(obj);
2418         if (ext != NULL)
2419                 osc_extent_put(env, ext);
2420         RETURN(rc);
2421 }
2422
2423 /**
2424  * This is called when a page is picked up by kernel to write out.
2425  *
2426  * We should find out the corresponding extent and add the whole extent
2427  * into urgent list. The extent may be being truncated or used, handle it
2428  * carefully.
2429  */
2430 int osc_flush_async_page(const struct lu_env *env, struct cl_io *io,
2431                          struct osc_page *ops)
2432 {
2433         struct osc_extent *ext   = NULL;
2434         struct osc_object *obj   = cl2osc(ops->ops_cl.cpl_obj);
2435         struct cl_page    *cp    = ops->ops_cl.cpl_page;
2436         pgoff_t            index = osc_index(ops);
2437         struct osc_async_page *oap = &ops->ops_oap;
2438         bool unplug = false;
2439         int rc = 0;
2440         ENTRY;
2441
2442         osc_object_lock(obj);
2443         ext = osc_extent_lookup(obj, index);
2444         if (ext == NULL) {
2445                 osc_extent_tree_dump(D_ERROR, obj);
2446                 LASSERTF(0, "page index %lu is NOT covered.\n", index);
2447         }
2448
2449         switch (ext->oe_state) {
2450         case OES_RPC:
2451         case OES_LOCK_DONE:
2452                 CL_PAGE_DEBUG(D_ERROR, env, cp, "flush an in-rpc page?\n");
2453                 LASSERT(0);
2454                 break;
2455         case OES_LOCKING:
2456                 /* If we know this extent is being written out, we should abort
2457                  * so that the writer can make this page ready. Otherwise, there
2458                  * exists a deadlock problem because other process can wait for
2459                  * page writeback bit holding page lock; and meanwhile in
2460                  * vvp_page_make_ready(), we need to grab page lock before
2461                  * really sending the RPC. */
2462         case OES_TRUNC:
2463                 /* race with truncate, page will be redirtied */
2464         case OES_ACTIVE:
2465                 /* The extent is active so we need to abort and let the caller
2466                  * re-dirty the page. If we continued on here, and we were the
2467                  * one making the extent active, we could deadlock waiting for
2468                  * the page writeback to clear but it won't because the extent
2469                  * is active and won't be written out. */
2470                 GOTO(out, rc = -EAGAIN);
2471         default:
2472                 break;
2473         }
2474
2475         rc = cl_page_prep(env, io, cp, CRT_WRITE);
2476         if (rc)
2477                 GOTO(out, rc);
2478
2479         spin_lock(&oap->oap_lock);
2480         oap->oap_async_flags |= ASYNC_READY|ASYNC_URGENT;
2481         spin_unlock(&oap->oap_lock);
2482
2483         if (memory_pressure_get())
2484                 ext->oe_memalloc = 1;
2485
2486         ext->oe_urgent = 1;
2487         if (ext->oe_state == OES_CACHE) {
2488                 OSC_EXTENT_DUMP(D_CACHE, ext,
2489                                 "flush page %p make it urgent.\n", oap);
2490                 if (list_empty(&ext->oe_link))
2491                         list_add_tail(&ext->oe_link, &obj->oo_urgent_exts);
2492                 unplug = true;
2493         }
2494         rc = 0;
2495         EXIT;
2496
2497 out:
2498         osc_object_unlock(obj);
2499         osc_extent_put(env, ext);
2500         if (unplug)
2501                 osc_io_unplug_async(env, osc_cli(obj), obj);
2502         return rc;
2503 }
2504
2505 /**
2506  * this is called when a sync waiter receives an interruption.  Its job is to
2507  * get the caller woken as soon as possible.  If its page hasn't been put in an
2508  * rpc yet it can dequeue immediately.  Otherwise it has to mark the rpc as
2509  * desiring interruption which will forcefully complete the rpc once the rpc
2510  * has timed out.
2511  */
2512 int osc_cancel_async_page(const struct lu_env *env, struct osc_page *ops)
2513 {
2514         struct osc_async_page *oap = &ops->ops_oap;
2515         struct osc_object     *obj = oap->oap_obj;
2516         struct client_obd     *cli = osc_cli(obj);
2517         struct osc_extent     *ext;
2518         struct osc_extent     *found = NULL;
2519         struct list_head            *plist;
2520         pgoff_t index = osc_index(ops);
2521         int     rc = -EBUSY;
2522         int     cmd;
2523         ENTRY;
2524
2525         LASSERT(!oap->oap_interrupted);
2526         oap->oap_interrupted = 1;
2527
2528         /* Find out the caching extent */
2529         osc_object_lock(obj);
2530         if (oap->oap_cmd & OBD_BRW_WRITE) {
2531                 plist = &obj->oo_urgent_exts;
2532                 cmd   = OBD_BRW_WRITE;
2533         } else {
2534                 plist = &obj->oo_reading_exts;
2535                 cmd   = OBD_BRW_READ;
2536         }
2537         list_for_each_entry(ext, plist, oe_link) {
2538                 if (ext->oe_start <= index && ext->oe_end >= index) {
2539                         LASSERT(ext->oe_state == OES_LOCK_DONE);
2540                         /* For OES_LOCK_DONE state extent, it has already held
2541                          * a refcount for RPC. */
2542                         found = osc_extent_get(ext);
2543                         break;
2544                 }
2545         }
2546         if (found != NULL) {
2547                 list_del_init(&found->oe_link);
2548                 osc_update_pending(obj, cmd, -found->oe_nr_pages);
2549                 osc_object_unlock(obj);
2550
2551                 osc_extent_finish(env, found, 0, -EINTR);
2552                 osc_extent_put(env, found);
2553                 rc = 0;
2554         } else {
2555                 osc_object_unlock(obj);
2556                 /* ok, it's been put in an rpc. only one oap gets a request
2557                  * reference */
2558                 if (oap->oap_request != NULL) {
2559                         ptlrpc_mark_interrupted(oap->oap_request);
2560                         ptlrpcd_wake(oap->oap_request);
2561                         ptlrpc_req_finished(oap->oap_request);
2562                         oap->oap_request = NULL;
2563                 }
2564         }
2565
2566         osc_list_maint(cli, obj);
2567         RETURN(rc);
2568 }
2569
2570 int osc_queue_sync_pages(const struct lu_env *env, struct osc_object *obj,
2571                          struct list_head *list, int cmd, int brw_flags)
2572 {
2573         struct client_obd     *cli = osc_cli(obj);
2574         struct osc_extent     *ext;
2575         struct osc_async_page *oap;
2576         int     page_count = 0;
2577         int     mppr       = cli->cl_max_pages_per_rpc;
2578         pgoff_t start      = CL_PAGE_EOF;
2579         pgoff_t end        = 0;
2580         ENTRY;
2581
2582         list_for_each_entry(oap, list, oap_pending_item) {
2583                 pgoff_t index = osc_index(oap2osc(oap));
2584                 if (index > end)
2585                         end = index;
2586                 if (index < start)
2587                         start = index;
2588                 ++page_count;
2589                 mppr <<= (page_count > mppr);
2590         }
2591
2592         ext = osc_extent_alloc(obj);
2593         if (ext == NULL) {
2594                 list_for_each_entry(oap, list, oap_pending_item) {
2595                         list_del_init(&oap->oap_pending_item);
2596                         osc_ap_completion(env, cli, oap, 0, -ENOMEM);
2597                 }
2598                 RETURN(-ENOMEM);
2599         }
2600
2601         ext->oe_rw = !!(cmd & OBD_BRW_READ);
2602         ext->oe_urgent = 1;
2603         ext->oe_start = start;
2604         ext->oe_end = ext->oe_max_end = end;
2605         ext->oe_obj = obj;
2606         ext->oe_srvlock = !!(brw_flags & OBD_BRW_SRVLOCK);
2607         ext->oe_nr_pages = page_count;
2608         ext->oe_mppr = mppr;
2609         list_splice_init(list, &ext->oe_pages);
2610
2611         osc_object_lock(obj);
2612         /* Reuse the initial refcount for RPC, don't drop it */
2613         osc_extent_state_set(ext, OES_LOCK_DONE);
2614         if (cmd & OBD_BRW_WRITE) {
2615                 list_add_tail(&ext->oe_link, &obj->oo_urgent_exts);
2616                 osc_update_pending(obj, OBD_BRW_WRITE, page_count);
2617         } else {
2618                 list_add_tail(&ext->oe_link, &obj->oo_reading_exts);
2619                 osc_update_pending(obj, OBD_BRW_READ, page_count);
2620         }
2621         osc_object_unlock(obj);
2622
2623         osc_io_unplug(env, cli, obj, PDL_POLICY_ROUND);
2624         RETURN(0);
2625 }
2626
2627 /**
2628  * Called by osc_io_setattr_start() to freeze and destroy covering extents.
2629  */
2630 int osc_cache_truncate_start(const struct lu_env *env, struct osc_io *oio,
2631                              struct osc_object *obj, __u64 size)
2632 {
2633         struct client_obd *cli = osc_cli(obj);
2634         struct osc_extent *ext;
2635         struct osc_extent *waiting = NULL;
2636         pgoff_t index;
2637         struct list_head list = LIST_HEAD_INIT(list);
2638         int result = 0;
2639         bool partial;
2640         ENTRY;
2641
2642         /* pages with index greater or equal to index will be truncated. */
2643         index = cl_index(osc2cl(obj), size);
2644         partial = size > cl_offset(osc2cl(obj), index);
2645
2646 again:
2647         osc_object_lock(obj);
2648         ext = osc_extent_search(obj, index);
2649         if (ext == NULL)
2650                 ext = first_extent(obj);
2651         else if (ext->oe_end < index)
2652                 ext = next_extent(ext);
2653         while (ext != NULL) {
2654                 EASSERT(ext->oe_state != OES_TRUNC, ext);
2655
2656                 if (ext->oe_state > OES_CACHE || ext->oe_urgent) {
2657                         /* if ext is in urgent state, it means there must exist
2658                          * a page already having been flushed by write_page().
2659                          * We have to wait for this extent because we can't
2660                          * truncate that page. */
2661                         LASSERT(!ext->oe_hp);
2662                         OSC_EXTENT_DUMP(D_CACHE, ext,
2663                                         "waiting for busy extent\n");
2664                         waiting = osc_extent_get(ext);
2665                         break;
2666                 }
2667
2668                 OSC_EXTENT_DUMP(D_CACHE, ext, "try to trunc:"LPU64".\n", size);
2669
2670                 osc_extent_get(ext);
2671                 if (ext->oe_state == OES_ACTIVE) {
2672                         /* though we grab inode mutex for write path, but we
2673                          * release it before releasing extent(in osc_io_end()),
2674                          * so there is a race window that an extent is still
2675                          * in OES_ACTIVE when truncate starts. */
2676                         LASSERT(!ext->oe_trunc_pending);
2677                         ext->oe_trunc_pending = 1;
2678                 } else {
2679                         EASSERT(ext->oe_state == OES_CACHE, ext);
2680                         osc_extent_state_set(ext, OES_TRUNC);
2681                         osc_update_pending(obj, OBD_BRW_WRITE,
2682                                            -ext->oe_nr_pages);
2683                 }
2684                 EASSERT(list_empty(&ext->oe_link), ext);
2685                 list_add_tail(&ext->oe_link, &list);
2686
2687                 ext = next_extent(ext);
2688         }
2689         osc_object_unlock(obj);
2690
2691         osc_list_maint(cli, obj);
2692
2693         while (!list_empty(&list)) {
2694                 int rc;
2695
2696                 ext = list_entry(list.next, struct osc_extent, oe_link);
2697                 list_del_init(&ext->oe_link);
2698
2699                 /* extent may be in OES_ACTIVE state because inode mutex
2700                  * is released before osc_io_end() in file write case */
2701                 if (ext->oe_state != OES_TRUNC)
2702                         osc_extent_wait(env, ext, OES_TRUNC);
2703
2704                 rc = osc_extent_truncate(ext, index, partial);
2705                 if (rc < 0) {
2706                         if (result == 0)
2707                                 result = rc;
2708
2709                         OSC_EXTENT_DUMP(D_ERROR, ext,
2710                                         "truncate error %d\n", rc);
2711                 } else if (ext->oe_nr_pages == 0) {
2712                         osc_extent_remove(ext);
2713                 } else {
2714                         /* this must be an overlapped extent which means only
2715                          * part of pages in this extent have been truncated.
2716                          */
2717                         EASSERTF(ext->oe_start <= index, ext,
2718                                  "trunc index = %lu/%d.\n", index, partial);
2719                         /* fix index to skip this partially truncated extent */
2720                         index = ext->oe_end + 1;
2721                         partial = false;
2722
2723                         /* we need to hold this extent in OES_TRUNC state so
2724                          * that no writeback will happen. This is to avoid
2725                          * BUG 17397. */
2726                         LASSERT(oio->oi_trunc == NULL);
2727                         oio->oi_trunc = osc_extent_get(ext);
2728                         OSC_EXTENT_DUMP(D_CACHE, ext,
2729                                         "trunc at "LPU64"\n", size);
2730                 }
2731                 osc_extent_put(env, ext);
2732         }
2733         if (waiting != NULL) {
2734                 int rc;
2735
2736                 /* ignore the result of osc_extent_wait the write initiator
2737                  * should take care of it. */
2738                 rc = osc_extent_wait(env, waiting, OES_INV);
2739                 if (rc < 0)
2740                         OSC_EXTENT_DUMP(D_CACHE, waiting, "error: %d.\n", rc);
2741
2742                 osc_extent_put(env, waiting);
2743                 waiting = NULL;
2744                 goto again;
2745         }
2746         RETURN(result);
2747 }
2748
2749 /**
2750  * Called after osc_io_setattr_end to add oio->oi_trunc back to cache.
2751  */
2752 void osc_cache_truncate_end(const struct lu_env *env, struct osc_io *oio,
2753                             struct osc_object *obj)
2754 {
2755         struct osc_extent *ext = oio->oi_trunc;
2756
2757         oio->oi_trunc = NULL;
2758         if (ext != NULL) {
2759                 bool unplug = false;
2760
2761                 EASSERT(ext->oe_nr_pages > 0, ext);
2762                 EASSERT(ext->oe_state == OES_TRUNC, ext);
2763                 EASSERT(!ext->oe_urgent, ext);
2764
2765                 OSC_EXTENT_DUMP(D_CACHE, ext, "trunc -> cache.\n");
2766                 osc_object_lock(obj);
2767                 osc_extent_state_set(ext, OES_CACHE);
2768                 if (ext->oe_fsync_wait && !ext->oe_urgent) {
2769                         ext->oe_urgent = 1;
2770                         list_move_tail(&ext->oe_link, &obj->oo_urgent_exts);
2771                         unplug = true;
2772                 }
2773                 osc_update_pending(obj, OBD_BRW_WRITE, ext->oe_nr_pages);
2774                 osc_object_unlock(obj);
2775                 osc_extent_put(env, ext);
2776
2777                 if (unplug)
2778                         osc_io_unplug_async(env, osc_cli(obj), obj);
2779         }
2780 }
2781
2782 /**
2783  * Wait for extents in a specific range to be written out.
2784  * The caller must have called osc_cache_writeback_range() to issue IO
2785  * otherwise it will take a long time for this function to finish.
2786  *
2787  * Caller must hold inode_mutex , or cancel exclusive dlm lock so that
2788  * nobody else can dirty this range of file while we're waiting for
2789  * extents to be written.
2790  */
2791 int osc_cache_wait_range(const struct lu_env *env, struct osc_object *obj,
2792                          pgoff_t start, pgoff_t end)
2793 {
2794         struct osc_extent *ext;
2795         pgoff_t index = start;
2796         int     result = 0;
2797         ENTRY;
2798
2799 again:
2800         osc_object_lock(obj);
2801         ext = osc_extent_search(obj, index);
2802         if (ext == NULL)
2803                 ext = first_extent(obj);
2804         else if (ext->oe_end < index)
2805                 ext = next_extent(ext);
2806         while (ext != NULL) {
2807                 int rc;
2808
2809                 if (ext->oe_start > end)
2810                         break;
2811
2812                 if (!ext->oe_fsync_wait) {
2813                         ext = next_extent(ext);
2814                         continue;
2815                 }
2816
2817                 EASSERT(ergo(ext->oe_state == OES_CACHE,
2818                              ext->oe_hp || ext->oe_urgent), ext);
2819                 EASSERT(ergo(ext->oe_state == OES_ACTIVE,
2820                              !ext->oe_hp && ext->oe_urgent), ext);
2821
2822                 index = ext->oe_end + 1;
2823                 osc_extent_get(ext);
2824                 osc_object_unlock(obj);
2825
2826                 rc = osc_extent_wait(env, ext, OES_INV);
2827                 if (result == 0)
2828                         result = rc;
2829                 osc_extent_put(env, ext);
2830                 goto again;
2831         }
2832         osc_object_unlock(obj);
2833
2834         OSC_IO_DEBUG(obj, "sync file range.\n");
2835         RETURN(result);
2836 }
2837
2838 /**
2839  * Called to write out a range of osc object.
2840  *
2841  * @hp     : should be set this is caused by lock cancel;
2842  * @discard: is set if dirty pages should be dropped - file will be deleted or
2843  *         truncated, this implies there is no partially discarding extents.
2844  *
2845  * Return how many pages will be issued, or error code if error occurred.
2846  */
2847 int osc_cache_writeback_range(const struct lu_env *env, struct osc_object *obj,
2848                               pgoff_t start, pgoff_t end, int hp, int discard)
2849 {
2850         struct osc_extent *ext;
2851         struct list_head discard_list = LIST_HEAD_INIT(discard_list);
2852         bool unplug = false;
2853         int result = 0;
2854         ENTRY;
2855
2856         osc_object_lock(obj);
2857         ext = osc_extent_search(obj, start);
2858         if (ext == NULL)
2859                 ext = first_extent(obj);
2860         else if (ext->oe_end < start)
2861                 ext = next_extent(ext);
2862         while (ext != NULL) {
2863                 if (ext->oe_start > end)
2864                         break;
2865
2866                 ext->oe_fsync_wait = 1;
2867                 switch (ext->oe_state) {
2868                 case OES_CACHE:
2869                         result += ext->oe_nr_pages;
2870                         if (!discard) {
2871                                 struct list_head *list = NULL;
2872                                 if (hp) {
2873                                         EASSERT(!ext->oe_hp, ext);
2874                                         ext->oe_hp = 1;
2875                                         list = &obj->oo_hp_exts;
2876                                 } else if (!ext->oe_urgent) {
2877                                         ext->oe_urgent = 1;
2878                                         list = &obj->oo_urgent_exts;
2879                                 }
2880                                 if (list != NULL)
2881                                         list_move_tail(&ext->oe_link, list);
2882                                 unplug = true;
2883                         } else {
2884                                 /* the only discarder is lock cancelling, so
2885                                  * [start, end] must contain this extent */
2886                                 EASSERT(ext->oe_start >= start &&
2887                                         ext->oe_max_end <= end, ext);
2888                                 osc_extent_state_set(ext, OES_LOCKING);
2889                                 ext->oe_owner = current;
2890                                 list_move_tail(&ext->oe_link,
2891                                                    &discard_list);
2892                                 osc_update_pending(obj, OBD_BRW_WRITE,
2893                                                    -ext->oe_nr_pages);
2894                         }
2895                         break;
2896                 case OES_ACTIVE:
2897                         /* It's pretty bad to wait for ACTIVE extents, because
2898                          * we don't know how long we will wait for it to be
2899                          * flushed since it may be blocked at awaiting more
2900                          * grants. We do this for the correctness of fsync. */
2901                         LASSERT(hp == 0 && discard == 0);
2902                         ext->oe_urgent = 1;
2903                         break;
2904                 case OES_TRUNC:
2905                         /* this extent is being truncated, can't do anything
2906                          * for it now. it will be set to urgent after truncate
2907                          * is finished in osc_cache_truncate_end(). */
2908                 default:
2909                         break;
2910                 }
2911                 ext = next_extent(ext);
2912         }
2913         osc_object_unlock(obj);
2914
2915         LASSERT(ergo(!discard, list_empty(&discard_list)));
2916         if (!list_empty(&discard_list)) {
2917                 struct osc_extent *tmp;
2918                 int rc;
2919
2920                 osc_list_maint(osc_cli(obj), obj);
2921                 list_for_each_entry_safe(ext, tmp, &discard_list, oe_link) {
2922                         list_del_init(&ext->oe_link);
2923                         EASSERT(ext->oe_state == OES_LOCKING, ext);
2924
2925                         /* Discard caching pages. We don't actually write this
2926                          * extent out but we complete it as if we did. */
2927                         rc = osc_extent_make_ready(env, ext);
2928                         if (unlikely(rc < 0)) {
2929                                 OSC_EXTENT_DUMP(D_ERROR, ext,
2930                                                 "make_ready returned %d\n", rc);
2931                                 if (result >= 0)
2932                                         result = rc;
2933                         }
2934
2935                         /* finish the extent as if the pages were sent */
2936                         osc_extent_finish(env, ext, 0, 0);
2937                 }
2938         }
2939
2940         if (unplug)
2941                 osc_io_unplug(env, osc_cli(obj), obj, PDL_POLICY_ROUND);
2942
2943         if (hp || discard) {
2944                 int rc;
2945                 rc = osc_cache_wait_range(env, obj, start, end);
2946                 if (result >= 0 && rc < 0)
2947                         result = rc;
2948         }
2949
2950         OSC_IO_DEBUG(obj, "pageout [%lu, %lu], %d.\n", start, end, result);
2951         RETURN(result);
2952 }
2953
2954 /**
2955  * Returns a list of pages by a given [start, end] of \a obj.
2956  *
2957  * \param resched If not NULL, then we give up before hogging CPU for too
2958  * long and set *resched = 1, in that case caller should implement a retry
2959  * logic.
2960  *
2961  * Gang tree lookup (radix_tree_gang_lookup()) optimization is absolutely
2962  * crucial in the face of [offset, EOF] locks.
2963  *
2964  * Return at least one page in @queue unless there is no covered page.
2965  */
2966 int osc_page_gang_lookup(const struct lu_env *env, struct cl_io *io,
2967                         struct osc_object *osc, pgoff_t start, pgoff_t end,
2968                         osc_page_gang_cbt cb, void *cbdata)
2969 {
2970         struct osc_page *ops;
2971         void            **pvec;
2972         pgoff_t         idx;
2973         unsigned int    nr;
2974         unsigned int    i;
2975         unsigned int    j;
2976         int             res = CLP_GANG_OKAY;
2977         bool            tree_lock = true;
2978         ENTRY;
2979
2980         idx = start;
2981         pvec = osc_env_info(env)->oti_pvec;
2982         spin_lock(&osc->oo_tree_lock);
2983         while ((nr = radix_tree_gang_lookup(&osc->oo_tree, pvec,
2984                                             idx, OTI_PVEC_SIZE)) > 0) {
2985                 struct cl_page *page;
2986                 bool end_of_region = false;
2987
2988                 for (i = 0, j = 0; i < nr; ++i) {
2989                         ops = pvec[i];
2990                         pvec[i] = NULL;
2991
2992                         idx = osc_index(ops);
2993                         if (idx > end) {
2994                                 end_of_region = true;
2995                                 break;
2996                         }
2997
2998                         page = ops->ops_cl.cpl_page;
2999                         LASSERT(page->cp_type == CPT_CACHEABLE);
3000                         if (page->cp_state == CPS_FREEING)
3001                                 continue;
3002
3003                         cl_page_get(page);
3004                         lu_ref_add_atomic(&page->cp_reference,
3005                                           "gang_lookup", current);
3006                         pvec[j++] = ops;
3007                 }
3008                 ++idx;
3009
3010                 /*
3011                  * Here a delicate locking dance is performed. Current thread
3012                  * holds a reference to a page, but has to own it before it
3013                  * can be placed into queue. Owning implies waiting, so
3014                  * radix-tree lock is to be released. After a wait one has to
3015                  * check that pages weren't truncated (cl_page_own() returns
3016                  * error in the latter case).
3017                  */
3018                 spin_unlock(&osc->oo_tree_lock);
3019                 tree_lock = false;
3020
3021                 for (i = 0; i < j; ++i) {
3022                         ops = pvec[i];
3023                         if (res == CLP_GANG_OKAY)
3024                                 res = (*cb)(env, io, ops, cbdata);
3025
3026                         page = ops->ops_cl.cpl_page;
3027                         lu_ref_del(&page->cp_reference, "gang_lookup", current);
3028                         cl_page_put(env, page);
3029                 }
3030                 if (nr < OTI_PVEC_SIZE || end_of_region)
3031                         break;
3032
3033                 if (res == CLP_GANG_OKAY && need_resched())
3034                         res = CLP_GANG_RESCHED;
3035                 if (res != CLP_GANG_OKAY)
3036                         break;
3037
3038                 spin_lock(&osc->oo_tree_lock);
3039                 tree_lock = true;
3040         }
3041         if (tree_lock)
3042                 spin_unlock(&osc->oo_tree_lock);
3043         RETURN(res);
3044 }
3045
3046 /**
3047  * Check if page @page is covered by an extra lock or discard it.
3048  */
3049 static int check_and_discard_cb(const struct lu_env *env, struct cl_io *io,
3050                                 struct osc_page *ops, void *cbdata)
3051 {
3052         struct osc_thread_info *info = osc_env_info(env);
3053         struct cl_lock *lock = cbdata;
3054         pgoff_t index;
3055
3056         index = osc_index(ops);
3057         if (index >= info->oti_fn_index) {
3058                 struct cl_lock *tmp;
3059                 struct cl_page *page = ops->ops_cl.cpl_page;
3060
3061                 /* refresh non-overlapped index */
3062                 tmp = cl_lock_at_pgoff(env, lock->cll_descr.cld_obj, index,
3063                                        lock, 1, 0);
3064                 if (tmp != NULL) {
3065                         /* Cache the first-non-overlapped index so as to skip
3066                          * all pages within [index, oti_fn_index). This
3067                          * is safe because if tmp lock is canceled, it will
3068                          * discard these pages. */
3069                         info->oti_fn_index = tmp->cll_descr.cld_end + 1;
3070                         if (tmp->cll_descr.cld_end == CL_PAGE_EOF)
3071                                 info->oti_fn_index = CL_PAGE_EOF;
3072                         cl_lock_put(env, tmp);
3073                 } else if (cl_page_own(env, io, page) == 0) {
3074                         /* discard the page */
3075                         cl_page_discard(env, io, page);
3076                         cl_page_disown(env, io, page);
3077                 } else {
3078                         LASSERT(page->cp_state == CPS_FREEING);
3079                 }
3080         }
3081
3082         info->oti_next_index = index + 1;
3083         return CLP_GANG_OKAY;
3084 }
3085
3086 static int discard_cb(const struct lu_env *env, struct cl_io *io,
3087                       struct osc_page *ops, void *cbdata)
3088 {
3089         struct osc_thread_info *info = osc_env_info(env);
3090         struct cl_lock *lock = cbdata;
3091         struct cl_page *page = ops->ops_cl.cpl_page;
3092
3093         LASSERT(lock->cll_descr.cld_mode >= CLM_WRITE);
3094
3095         /* page is top page. */
3096         info->oti_next_index = osc_index(ops) + 1;
3097         if (cl_page_own(env, io, page) == 0) {
3098                 KLASSERT(ergo(page->cp_type == CPT_CACHEABLE,
3099                               !PageDirty(cl_page_vmpage(page))));
3100
3101                 /* discard the page */
3102                 cl_page_discard(env, io, page);
3103                 cl_page_disown(env, io, page);
3104         } else {
3105                 LASSERT(page->cp_state == CPS_FREEING);
3106         }
3107
3108         return CLP_GANG_OKAY;
3109 }
3110
3111 /**
3112  * Discard pages protected by the given lock. This function traverses radix
3113  * tree to find all covering pages and discard them. If a page is being covered
3114  * by other locks, it should remain in cache.
3115  *
3116  * If error happens on any step, the process continues anyway (the reasoning
3117  * behind this being that lock cancellation cannot be delayed indefinitely).
3118  */
3119 int osc_lock_discard_pages(const struct lu_env *env, struct osc_lock *ols)
3120 {
3121         struct osc_thread_info *info = osc_env_info(env);
3122         struct cl_io *io = &info->oti_io;
3123         struct cl_object *osc = ols->ols_cl.cls_obj;
3124         struct cl_lock *lock = ols->ols_cl.cls_lock;
3125         struct cl_lock_descr *descr = &lock->cll_descr;
3126         osc_page_gang_cbt cb;
3127         int res;
3128         int result;
3129
3130         ENTRY;
3131
3132         io->ci_obj = cl_object_top(osc);
3133         io->ci_ignore_layout = 1;
3134         result = cl_io_init(env, io, CIT_MISC, io->ci_obj);
3135         if (result != 0)
3136                 GOTO(out, result);
3137
3138         cb = descr->cld_mode == CLM_READ ? check_and_discard_cb : discard_cb;
3139         info->oti_fn_index = info->oti_next_index = descr->cld_start;
3140         do {
3141                 res = osc_page_gang_lookup(env, io, cl2osc(osc),
3142                                            info->oti_next_index, descr->cld_end,
3143                                            cb, (void *)lock);
3144                 if (info->oti_next_index > descr->cld_end)
3145                         break;
3146
3147                 if (res == CLP_GANG_RESCHED)
3148                         cond_resched();
3149         } while (res != CLP_GANG_OKAY);
3150 out:
3151         cl_io_fini(env, io);
3152         RETURN(result);
3153 }
3154
3155
3156 /** @} osc */