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_sync)
  80                 *buf++ = 'S';
  81         if (ext->oe_srvlock)
  82                 *buf++ = 's';
  83         if (ext->oe_hp)
  84                 *buf++ = 'h';
  85         if (ext->oe_urgent)
  86                 *buf++ = 'u';
  87         if (ext->oe_memalloc)
  88                 *buf++ = 'm';
  89         if (ext->oe_trunc_pending)
  90                 *buf++ = 't';
  91         if (ext->oe_fsync_wait)
  92                 *buf++ = 'Y';
  93         *buf = 0;
  94         return flags;
  95 }
  96
  97 static inline char list_empty_marker(struct list_head *list)
  98 {
  99         return list_empty(list) ? '-' : '+';
 100 }
 101
 102 #define EXTSTR       "[%lu -> %lu/%lu]"
 103 #define EXTPARA(ext) (ext)->oe_start, (ext)->oe_end, (ext)->oe_max_end
 104 static const char *oes_strings[] = {
 105         "inv", "active", "cache", "locking", "lockdone", "rpc", "trunc", NULL };
 106
 107 #define OSC_EXTENT_DUMP(lvl, extent, fmt, ...) do {                           \
 108         struct osc_extent *__ext = (extent);                                  \
 109         char __buf[16];                                                       \
 110                                                                               \
 111         CDEBUG(lvl,                                                           \
 112                 "extent %p@{" EXTSTR ", "                                     \
 113                 "[%d|%d|%c|%s|%s|%p], [%d|%d|%c|%c|%p|%u|%p]} " fmt,          \
 114                 /* ----- extent part 0 ----- */                               \
 115                 __ext, EXTPARA(__ext),                                        \
 116                 /* ----- part 1 ----- */                                      \
 117                 atomic_read(&__ext->oe_refc),                         \
 118                 atomic_read(&__ext->oe_users),                        \
 119                 list_empty_marker(&__ext->oe_link),                           \
 120                 oes_strings[__ext->oe_state], ext_flags(__ext, __buf),        \
 121                 __ext->oe_obj,                                                \
 122                 /* ----- part 2 ----- */                                      \
 123                 __ext->oe_grants, __ext->oe_nr_pages,                         \
 124                 list_empty_marker(&__ext->oe_pages),                          \
 125                 waitqueue_active(&__ext->oe_waitq) ? '+' : '-',               \
 126                 __ext->oe_dlmlock, __ext->oe_mppr, __ext->oe_owner,           \
 127                 /* ----- part 4 ----- */                                      \
 128                 ## __VA_ARGS__);                                              \
 129         if (lvl == D_ERROR && __ext->oe_dlmlock != NULL)                      \
 130                 LDLM_ERROR(__ext->oe_dlmlock, "extent: %p\n", __ext);         \
 131         else                                                                  \
 132                 LDLM_DEBUG(__ext->oe_dlmlock, "extent: %p\n", __ext);         \
 133 } while (0)
 134
 135 #undef EASSERTF
 136 #define EASSERTF(expr, ext, fmt, args...) do {                          \
 137         if (!(expr)) {                                                  \
 138                 OSC_EXTENT_DUMP(D_ERROR, (ext), fmt, ##args);           \
 139                 osc_extent_tree_dump(D_ERROR, (ext)->oe_obj);           \
 140                 LASSERT(expr);                                          \
 141         }                                                               \
 142 } while (0)
 143
 144 #undef EASSERT
 145 #define EASSERT(expr, ext) EASSERTF(expr, ext, "\n")
 146
 147 static inline struct osc_extent *rb_extent(struct rb_node *n)
 148 {
 149         if (n == NULL)
 150                 return NULL;
 151
 152         return container_of(n, struct osc_extent, oe_node);
 153 }
 154
 155 static inline struct osc_extent *next_extent(struct osc_extent *ext)
 156 {
 157         if (ext == NULL)
 158                 return NULL;
 159
 160         LASSERT(ext->oe_intree);
 161         return rb_extent(rb_next(&ext->oe_node));
 162 }
 163
 164 static inline struct osc_extent *prev_extent(struct osc_extent *ext)
 165 {
 166         if (ext == NULL)
 167                 return NULL;
 168
 169         LASSERT(ext->oe_intree);
 170         return rb_extent(rb_prev(&ext->oe_node));
 171 }
 172
 173 static inline struct osc_extent *first_extent(struct osc_object *obj)
 174 {
 175         return rb_extent(rb_first(&obj->oo_root));
 176 }
 177
 178 /* object must be locked by caller. */
 179 static int osc_extent_sanity_check0(struct osc_extent *ext,
 180                                     const char *func, const int line)
 181 {
 182         struct osc_object *obj = ext->oe_obj;
 183         struct osc_async_page *oap;
 184         int page_count;
 185         int rc = 0;
 186
 187         if (!osc_object_is_locked(obj))
 188                 GOTO(out, rc = 9);
 189
 190         if (ext->oe_state >= OES_STATE_MAX)
 191                 GOTO(out, rc = 10);
 192
 193         if (atomic_read(&ext->oe_refc) <= 0)
 194                 GOTO(out, rc = 20);
 195
 196         if (atomic_read(&ext->oe_refc) < atomic_read(&ext->oe_users))
 197                 GOTO(out, rc = 30);
 198
 199         switch (ext->oe_state) {
 200         case OES_INV:
 201                 if (ext->oe_nr_pages > 0 || !list_empty(&ext->oe_pages))
 202                         GOTO(out, rc = 35);
 203                 GOTO(out, rc = 0);
 204                 break;
 205         case OES_ACTIVE:
 206                 if (atomic_read(&ext->oe_users) == 0)
 207                         GOTO(out, rc = 40);
 208                 if (ext->oe_hp)
 209                         GOTO(out, rc = 50);
 210                 if (ext->oe_fsync_wait && !ext->oe_urgent)
 211                         GOTO(out, rc = 55);
 212                 break;
 213         case OES_CACHE:
 214                 if (ext->oe_grants == 0)
 215                         GOTO(out, rc = 60);
 216                 if (ext->oe_fsync_wait && !ext->oe_urgent && !ext->oe_hp)
 217                         GOTO(out, rc = 65);
 218         default:
 219                 if (atomic_read(&ext->oe_users) > 0)
 220                         GOTO(out, rc = 70);
 221         }
 222
 223         if (ext->oe_max_end < ext->oe_end || ext->oe_end < ext->oe_start)
 224                 GOTO(out, rc = 80);
 225
 226         if (ext->oe_sync && ext->oe_grants > 0)
 227                 GOTO(out, rc = 90);
 228
 229         if (ext->oe_dlmlock != NULL) {
 230                 struct ldlm_extent *extent;
 231
 232                 extent = &ext->oe_dlmlock->l_policy_data.l_extent;
 233                 if (!(extent->start <= cl_offset(osc2cl(obj), ext->oe_start) &&
 234                       extent->end   >= cl_offset(osc2cl(obj), ext->oe_max_end)))
 235                         GOTO(out, rc = 100);
 236
 237                 if (!(ext->oe_dlmlock->l_granted_mode & (LCK_PW | LCK_GROUP)))
 238                         GOTO(out, rc = 102);
 239         }
 240
 241         if (ext->oe_nr_pages > ext->oe_mppr)
 242                 GOTO(out, rc = 105);
 243
 244         /* Do not verify page list if extent is in RPC. This is because an
 245          * in-RPC extent is supposed to be exclusively accessible w/o lock. */
 246         if (ext->oe_state > OES_CACHE)
 247                 GOTO(out, rc = 0);
 248
 249         if (!extent_debug)
 250                 GOTO(out, rc = 0);
 251
 252         page_count = 0;
 253         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
 254                 pgoff_t index = osc_index(oap2osc(oap));
 255                 ++page_count;
 256                 if (index > ext->oe_end || index < ext->oe_start)
 257                         GOTO(out, rc = 110);
 258         }
 259         if (page_count != ext->oe_nr_pages)
 260                 GOTO(out, rc = 120);
 261
 262 out:
 263         if (rc != 0)
 264                 OSC_EXTENT_DUMP(D_ERROR, ext,
 265                                 "%s:%d sanity check %p failed with rc = %d\n",
 266                                 func, line, ext, rc);
 267         return rc;
 268 }
 269
 270 #define sanity_check_nolock(ext) \
 271         osc_extent_sanity_check0(ext, __func__, __LINE__)
 272
 273 #define sanity_check(ext) ({                                                   \
 274         int __res;                                                             \
 275         osc_object_lock((ext)->oe_obj);                                        \
 276         __res = sanity_check_nolock(ext);                                      \
 277         osc_object_unlock((ext)->oe_obj);                                      \
 278         __res;                                                                 \
 279 })
 280
 281
 282 /**
 283  * sanity check - to make sure there is no overlapped extent in the tree.
 284  */
 285 static int osc_extent_is_overlapped(struct osc_object *obj,
 286                                     struct osc_extent *ext)
 287 {
 288         struct osc_extent *tmp;
 289
 290         LASSERT(osc_object_is_locked(obj));
 291
 292         if (!extent_debug)
 293                 return 0;
 294
 295         for (tmp = first_extent(obj); tmp != NULL; tmp = next_extent(tmp)) {
 296                 if (tmp == ext)
 297                         continue;
 298                 if (tmp->oe_end >= ext->oe_start &&
 299                     tmp->oe_start <= ext->oe_end)
 300                         return 1;
 301         }
 302         return 0;
 303 }
 304
 305 static void osc_extent_state_set(struct osc_extent *ext, int state)
 306 {
 307         LASSERT(osc_object_is_locked(ext->oe_obj));
 308         LASSERT(state >= OES_INV && state < OES_STATE_MAX);
 309
 310         /* Never try to sanity check a state changing extent :-) */
 311         /* LASSERT(sanity_check_nolock(ext) == 0); */
 312
 313         /* TODO: validate the state machine */
 314         ext->oe_state = state;
 315         wake_up_all(&ext->oe_waitq);
 316 }
 317
 318 static struct osc_extent *osc_extent_alloc(struct osc_object *obj)
 319 {
 320         struct osc_extent *ext;
 321
 322         OBD_SLAB_ALLOC_PTR_GFP(ext, osc_extent_kmem, GFP_IOFS);
 323         if (ext == NULL)
 324                 return NULL;
 325
 326         RB_CLEAR_NODE(&ext->oe_node);
 327         ext->oe_obj = obj;
 328         atomic_set(&ext->oe_refc, 1);
 329         atomic_set(&ext->oe_users, 0);
 330         INIT_LIST_HEAD(&ext->oe_link);
 331         ext->oe_state = OES_INV;
 332         INIT_LIST_HEAD(&ext->oe_pages);
 333         init_waitqueue_head(&ext->oe_waitq);
 334         ext->oe_dlmlock = NULL;
 335
 336         return ext;
 337 }
 338
 339 static void osc_extent_free(struct osc_extent *ext)
 340 {
 341         OBD_SLAB_FREE_PTR(ext, osc_extent_kmem);
 342 }
 343
 344 static struct osc_extent *osc_extent_get(struct osc_extent *ext)
 345 {
 346         LASSERT(atomic_read(&ext->oe_refc) >= 0);
 347         atomic_inc(&ext->oe_refc);
 348         return ext;
 349 }
 350
 351 static void osc_extent_put(const struct lu_env *env, struct osc_extent *ext)
 352 {
 353         LASSERT(atomic_read(&ext->oe_refc) > 0);
 354         if (atomic_dec_and_test(&ext->oe_refc)) {
 355                 LASSERT(list_empty(&ext->oe_link));
 356                 LASSERT(atomic_read(&ext->oe_users) == 0);
 357                 LASSERT(ext->oe_state == OES_INV);
 358                 LASSERT(!ext->oe_intree);
 359
 360                 if (ext->oe_dlmlock != NULL) {
 361                         lu_ref_add(&ext->oe_dlmlock->l_reference,
 362                                    "osc_extent", ext);
 363                         LDLM_LOCK_PUT(ext->oe_dlmlock);
 364                         ext->oe_dlmlock = NULL;
 365                 }
 366                 osc_extent_free(ext);
 367         }
 368 }
 369
 370 /**
 371  * osc_extent_put_trust() is a special version of osc_extent_put() when
 372  * it's known that the caller is not the last user. This is to address the
 373  * problem of lacking of lu_env ;-).
 374  */
 375 static void osc_extent_put_trust(struct osc_extent *ext)
 376 {
 377         LASSERT(atomic_read(&ext->oe_refc) > 1);
 378         LASSERT(osc_object_is_locked(ext->oe_obj));
 379         atomic_dec(&ext->oe_refc);
 380 }
 381
 382 /**
 383  * Return the extent which includes pgoff @index, or return the greatest
 384  * previous extent in the tree.
 385  */
 386 static struct osc_extent *osc_extent_search(struct osc_object *obj,
 387                                             pgoff_t index)
 388 {
 389         struct rb_node    *n = obj->oo_root.rb_node;
 390         struct osc_extent *tmp, *p = NULL;
 391
 392         LASSERT(osc_object_is_locked(obj));
 393         while (n != NULL) {
 394                 tmp = rb_extent(n);
 395                 if (index < tmp->oe_start) {
 396                         n = n->rb_left;
 397                 } else if (index > tmp->oe_end) {
 398                         p = rb_extent(n);
 399                         n = n->rb_right;
 400                 } else {
 401                         return tmp;
 402                 }
 403         }
 404         return p;
 405 }
 406
 407 /*
 408  * Return the extent covering @index, otherwise return NULL.
 409  * caller must have held object lock.
 410  */
 411 static struct osc_extent *osc_extent_lookup(struct osc_object *obj,
 412                                             pgoff_t index)
 413 {
 414         struct osc_extent *ext;
 415
 416         ext = osc_extent_search(obj, index);
 417         if (ext != NULL && ext->oe_start <= index && index <= ext->oe_end)
 418                 return osc_extent_get(ext);
 419         return NULL;
 420 }
 421
 422 /* caller must have held object lock. */
 423 static void osc_extent_insert(struct osc_object *obj, struct osc_extent *ext)
 424 {
 425         struct rb_node   **n      = &obj->oo_root.rb_node;
 426         struct rb_node    *parent = NULL;
 427         struct osc_extent *tmp;
 428
 429         LASSERT(ext->oe_intree == 0);
 430         LASSERT(ext->oe_obj == obj);
 431         LASSERT(osc_object_is_locked(obj));
 432         while (*n != NULL) {
 433                 tmp = rb_extent(*n);
 434                 parent = *n;
 435
 436                 if (ext->oe_end < tmp->oe_start)
 437                         n = &(*n)->rb_left;
 438                 else if (ext->oe_start > tmp->oe_end)
 439                         n = &(*n)->rb_right;
 440                 else
 441                         EASSERTF(0, tmp, EXTSTR"\n", EXTPARA(ext));
 442         }
 443         rb_link_node(&ext->oe_node, parent, n);
 444         rb_insert_color(&ext->oe_node, &obj->oo_root);
 445         osc_extent_get(ext);
 446         ext->oe_intree = 1;
 447 }
 448
 449 /* caller must have held object lock. */
 450 static void osc_extent_erase(struct osc_extent *ext)
 451 {
 452         struct osc_object *obj = ext->oe_obj;
 453         LASSERT(osc_object_is_locked(obj));
 454         if (ext->oe_intree) {
 455                 rb_erase(&ext->oe_node, &obj->oo_root);
 456                 ext->oe_intree = 0;
 457                 /* rbtree held a refcount */
 458                 osc_extent_put_trust(ext);
 459         }
 460 }
 461
 462 static struct osc_extent *osc_extent_hold(struct osc_extent *ext)
 463 {
 464         struct osc_object *obj = ext->oe_obj;
 465
 466         LASSERT(osc_object_is_locked(obj));
 467         LASSERT(ext->oe_state == OES_ACTIVE || ext->oe_state == OES_CACHE);
 468         if (ext->oe_state == OES_CACHE) {
 469                 osc_extent_state_set(ext, OES_ACTIVE);
 470                 osc_update_pending(obj, OBD_BRW_WRITE, -ext->oe_nr_pages);
 471         }
 472         atomic_inc(&ext->oe_users);
 473         list_del_init(&ext->oe_link);
 474         return osc_extent_get(ext);
 475 }
 476
 477 static void __osc_extent_remove(struct osc_extent *ext)
 478 {
 479         LASSERT(osc_object_is_locked(ext->oe_obj));
 480         LASSERT(list_empty(&ext->oe_pages));
 481         osc_extent_erase(ext);
 482         list_del_init(&ext->oe_link);
 483         osc_extent_state_set(ext, OES_INV);
 484         OSC_EXTENT_DUMP(D_CACHE, ext, "destroyed.\n");
 485 }
 486
 487 static void osc_extent_remove(struct osc_extent *ext)
 488 {
 489         struct osc_object *obj = ext->oe_obj;
 490
 491         osc_object_lock(obj);
 492         __osc_extent_remove(ext);
 493         osc_object_unlock(obj);
 494 }
 495
 496 /**
 497  * This function is used to merge extents to get better performance. It checks
 498  * if @cur and @victim are contiguous at chunk level.
 499  */
 500 static int osc_extent_merge(const struct lu_env *env, struct osc_extent *cur,
 501                             struct osc_extent *victim)
 502 {
 503         struct osc_object *obj = cur->oe_obj;
 504         pgoff_t chunk_start;
 505         pgoff_t chunk_end;
 506         int ppc_bits;
 507
 508         LASSERT(cur->oe_state == OES_CACHE);
 509         LASSERT(osc_object_is_locked(obj));
 510         if (victim == NULL)
 511                 return -EINVAL;
 512
 513         if (victim->oe_state != OES_CACHE || victim->oe_fsync_wait)
 514                 return -EBUSY;
 515
 516         if (cur->oe_max_end != victim->oe_max_end)
 517                 return -ERANGE;
 518
 519         LASSERT(cur->oe_dlmlock == victim->oe_dlmlock);
 520         ppc_bits = osc_cli(obj)->cl_chunkbits - PAGE_CACHE_SHIFT;
 521         chunk_start = cur->oe_start >> ppc_bits;
 522         chunk_end   = cur->oe_end   >> ppc_bits;
 523         if (chunk_start   != (victim->oe_end >> ppc_bits) + 1 &&
 524             chunk_end + 1 != victim->oe_start >> ppc_bits)
 525                 return -ERANGE;
 526
 527         OSC_EXTENT_DUMP(D_CACHE, victim, "will be merged by %p.\n", cur);
 528
 529         cur->oe_start     = min(cur->oe_start, victim->oe_start);
 530         cur->oe_end       = max(cur->oe_end,   victim->oe_end);
 531         cur->oe_grants   += victim->oe_grants;
 532         cur->oe_nr_pages += victim->oe_nr_pages;
 533         /* only the following bits are needed to merge */
 534         cur->oe_urgent   |= victim->oe_urgent;
 535         cur->oe_memalloc |= victim->oe_memalloc;
 536         list_splice_init(&victim->oe_pages, &cur->oe_pages);
 537         list_del_init(&victim->oe_link);
 538         victim->oe_nr_pages = 0;
 539
 540         osc_extent_get(victim);
 541         __osc_extent_remove(victim);
 542         osc_extent_put(env, victim);
 543
 544         OSC_EXTENT_DUMP(D_CACHE, cur, "after merging %p.\n", victim);
 545         return 0;
 546 }
 547
 548 /**
 549  * Drop user count of osc_extent, and unplug IO asynchronously.
 550  */
 551 int osc_extent_release(const struct lu_env *env, struct osc_extent *ext)
 552 {
 553         struct osc_object *obj = ext->oe_obj;
 554         int rc = 0;
 555         ENTRY;
 556
 557         LASSERT(atomic_read(&ext->oe_users) > 0);
 558         LASSERT(sanity_check(ext) == 0);
 559         LASSERT(ext->oe_grants > 0);
 560
 561         if (atomic_dec_and_lock(&ext->oe_users, &obj->oo_lock)) {
 562                 LASSERT(ext->oe_state == OES_ACTIVE);
 563                 if (ext->oe_trunc_pending) {
 564                         /* a truncate process is waiting for this extent.
 565                          * This may happen due to a race, check
 566                          * osc_cache_truncate_start(). */
 567                         osc_extent_state_set(ext, OES_TRUNC);
 568                         ext->oe_trunc_pending = 0;
 569                 } else {
 570                         osc_extent_state_set(ext, OES_CACHE);
 571                         osc_update_pending(obj, OBD_BRW_WRITE,
 572                                            ext->oe_nr_pages);
 573
 574                         /* try to merge the previous and next extent. */
 575                         osc_extent_merge(env, ext, prev_extent(ext));
 576                         osc_extent_merge(env, ext, next_extent(ext));
 577
 578                         if (ext->oe_urgent)
 579                                 list_move_tail(&ext->oe_link,
 580                                                &obj->oo_urgent_exts);
 581                 }
 582                 osc_object_unlock(obj);
 583
 584                 osc_io_unplug_async(env, osc_cli(obj), obj);
 585         }
 586         osc_extent_put(env, ext);
 587         RETURN(rc);
 588 }
 589
 590 static inline int overlapped(struct osc_extent *ex1, struct osc_extent *ex2)
 591 {
 592         return !(ex1->oe_end < ex2->oe_start || ex2->oe_end < ex1->oe_start);
 593 }
 594
 595 /**
 596  * Find or create an extent which includes @index, core function to manage
 597  * extent tree.
 598  */
 599 struct osc_extent *osc_extent_find(const struct lu_env *env,
 600                                    struct osc_object *obj, pgoff_t index,
 601                                    int *grants)
 602 {
 603         struct client_obd *cli = osc_cli(obj);
 604         struct osc_lock   *olck;
 605         struct cl_lock_descr *descr;
 606         struct osc_extent *cur;
 607         struct osc_extent *ext;
 608         struct osc_extent *conflict = NULL;
 609         struct osc_extent *found = NULL;
 610         pgoff_t    chunk;
 611         pgoff_t    max_end;
 612         int        max_pages; /* max_pages_per_rpc */
 613         int        chunksize;
 614         int        ppc_bits; /* pages per chunk bits */
 615         int        chunk_mask;
 616         int        rc;
 617         ENTRY;
 618
 619         cur = osc_extent_alloc(obj);
 620         if (cur == NULL)
 621                 RETURN(ERR_PTR(-ENOMEM));
 622
 623         olck = osc_env_io(env)->oi_write_osclock;
 624         LASSERTF(olck != NULL, "page %lu is not covered by lock\n", index);
 625         LASSERT(olck->ols_state == OLS_GRANTED);
 626
 627         descr = &olck->ols_cl.cls_lock->cll_descr;
 628         LASSERT(descr->cld_mode >= CLM_WRITE);
 629
 630         LASSERT(cli->cl_chunkbits >= PAGE_CACHE_SHIFT);
 631         ppc_bits   = cli->cl_chunkbits - PAGE_CACHE_SHIFT;
 632         chunk_mask = ~((1 << ppc_bits) - 1);
 633         chunksize  = 1 << cli->cl_chunkbits;
 634         chunk      = index >> ppc_bits;
 635
 636         /* align end to rpc edge, rpc size may not be a power 2 integer. */
 637         max_pages = cli->cl_max_pages_per_rpc;
 638         LASSERT((max_pages & ~chunk_mask) == 0);
 639         max_end = index - (index % max_pages) + max_pages - 1;
 640         max_end = min_t(pgoff_t, max_end, descr->cld_end);
 641
 642         /* initialize new extent by parameters so far */
 643         cur->oe_max_end = max_end;
 644         cur->oe_start   = index & chunk_mask;
 645         cur->oe_end     = ((index + ~chunk_mask + 1) & chunk_mask) - 1;
 646         if (cur->oe_start < descr->cld_start)
 647                 cur->oe_start = descr->cld_start;
 648         if (cur->oe_end > max_end)
 649                 cur->oe_end = max_end;
 650         cur->oe_grants  = 0;
 651         cur->oe_mppr    = max_pages;
 652         if (olck->ols_dlmlock != NULL) {
 653                 LASSERT(olck->ols_hold);
 654                 cur->oe_dlmlock = LDLM_LOCK_GET(olck->ols_dlmlock);
 655                 lu_ref_add(&olck->ols_dlmlock->l_reference, "osc_extent", cur);
 656         }
 657
 658         /* grants has been allocated by caller */
 659         LASSERTF(*grants >= chunksize + cli->cl_extent_tax,
 660                  "%u/%u/%u.\n", *grants, chunksize, cli->cl_extent_tax);
 661         LASSERTF((max_end - cur->oe_start) < max_pages, EXTSTR"\n",
 662                  EXTPARA(cur));
 663
 664 restart:
 665         osc_object_lock(obj);
 666         ext = osc_extent_search(obj, cur->oe_start);
 667         if (ext == NULL)
 668                 ext = first_extent(obj);
 669         while (ext != NULL) {
 670                 loff_t ext_chk_start = ext->oe_start >> ppc_bits;
 671                 loff_t ext_chk_end   = ext->oe_end   >> ppc_bits;
 672
 673                 LASSERT(sanity_check_nolock(ext) == 0);
 674                 if (chunk > ext_chk_end + 1)
 675                         break;
 676
 677                 /* if covering by different locks, no chance to match */
 678                 if (olck->ols_dlmlock != ext->oe_dlmlock) {
 679                         EASSERTF(!overlapped(ext, cur), ext,
 680                                  EXTSTR"\n", EXTPARA(cur));
 681
 682                         ext = next_extent(ext);
 683                         continue;
 684                 }
 685
 686                 /* discontiguous chunks? */
 687                 if (chunk + 1 < ext_chk_start) {
 688                         ext = next_extent(ext);
 689                         continue;
 690                 }
 691
 692                 /* ok, from now on, ext and cur have these attrs:
 693                  * 1. covered by the same lock
 694                  * 2. contiguous at chunk level or overlapping. */
 695
 696                 if (overlapped(ext, cur)) {
 697                         /* cur is the minimum unit, so overlapping means
 698                          * full contain. */
 699                         EASSERTF((ext->oe_start <= cur->oe_start &&
 700                                   ext->oe_end >= cur->oe_end),
 701                                  ext, EXTSTR"\n", EXTPARA(cur));
 702
 703                         if (ext->oe_state > OES_CACHE || ext->oe_fsync_wait) {
 704                                 /* for simplicity, we wait for this extent to
 705                                  * finish before going forward. */
 706                                 conflict = osc_extent_get(ext);
 707                                 break;
 708                         }
 709
 710                         found = osc_extent_hold(ext);
 711                         break;
 712                 }
 713
 714                 /* non-overlapped extent */
 715                 if (ext->oe_state != OES_CACHE || ext->oe_fsync_wait) {
 716                         /* we can't do anything for a non OES_CACHE extent, or
 717                          * if there is someone waiting for this extent to be
 718                          * flushed, try next one. */
 719                         ext = next_extent(ext);
 720                         continue;
 721                 }
 722
 723                 /* check if they belong to the same rpc slot before trying to
 724                  * merge. the extents are not overlapped and contiguous at
 725                  * chunk level to get here. */
 726                 if (ext->oe_max_end != max_end) {
 727                         /* if they don't belong to the same RPC slot or
 728                          * max_pages_per_rpc has ever changed, do not merge. */
 729                         ext = next_extent(ext);
 730                         continue;
 731                 }
 732
 733                 /* it's required that an extent must be contiguous at chunk
 734                  * level so that we know the whole extent is covered by grant
 735                  * (the pages in the extent are NOT required to be contiguous).
 736                  * Otherwise, it will be too much difficult to know which
 737                  * chunks have grants allocated. */
 738
 739                 /* try to do front merge - extend ext's start */
 740                 if (chunk + 1 == ext_chk_start) {
 741                         /* ext must be chunk size aligned */
 742                         EASSERT((ext->oe_start & ~chunk_mask) == 0, ext);
 743
 744                         /* pull ext's start back to cover cur */
 745                         ext->oe_start   = cur->oe_start;
 746                         ext->oe_grants += chunksize;
 747                         *grants -= chunksize;
 748
 749                         found = osc_extent_hold(ext);
 750                 } else if (chunk == ext_chk_end + 1) {
 751                         /* rear merge */
 752                         ext->oe_end     = cur->oe_end;
 753                         ext->oe_grants += chunksize;
 754                         *grants -= chunksize;
 755
 756                         /* try to merge with the next one because we just fill
 757                          * in a gap */
 758                         if (osc_extent_merge(env, ext, next_extent(ext)) == 0)
 759                                 /* we can save extent tax from next extent */
 760                                 *grants += cli->cl_extent_tax;
 761
 762                         found = osc_extent_hold(ext);
 763                 }
 764                 if (found != NULL)
 765                         break;
 766
 767                 ext = next_extent(ext);
 768         }
 769
 770         osc_extent_tree_dump(D_CACHE, obj);
 771         if (found != NULL) {
 772                 LASSERT(conflict == NULL);
 773                 if (!IS_ERR(found)) {
 774                         LASSERT(found->oe_dlmlock == cur->oe_dlmlock);
 775                         OSC_EXTENT_DUMP(D_CACHE, found,
 776                                         "found caching ext for %lu.\n", index);
 777                 }
 778         } else if (conflict == NULL) {
 779                 /* create a new extent */
 780                 EASSERT(osc_extent_is_overlapped(obj, cur) == 0, cur);
 781                 cur->oe_grants = chunksize + cli->cl_extent_tax;
 782                 *grants -= cur->oe_grants;
 783                 LASSERT(*grants >= 0);
 784
 785                 cur->oe_state = OES_CACHE;
 786                 found = osc_extent_hold(cur);
 787                 osc_extent_insert(obj, cur);
 788                 OSC_EXTENT_DUMP(D_CACHE, cur, "add into tree %lu/%lu.\n",
 789                                 index, descr->cld_end);
 790         }
 791         osc_object_unlock(obj);
 792
 793         if (conflict != NULL) {
 794                 LASSERT(found == NULL);
 795
 796                 /* waiting for IO to finish. Please notice that it's impossible
 797                  * to be an OES_TRUNC extent. */
 798                 rc = osc_extent_wait(env, conflict, OES_INV);
 799                 osc_extent_put(env, conflict);
 800                 conflict = NULL;
 801                 if (rc < 0)
 802                         GOTO(out, found = ERR_PTR(rc));
 803
 804                 goto restart;
 805         }
 806         EXIT;
 807
 808 out:
 809         osc_extent_put(env, cur);
 810         LASSERT(*grants >= 0);
 811         return found;
 812 }
 813
 814 /**
 815  * Called when IO is finished to an extent.
 816  */
 817 int osc_extent_finish(const struct lu_env *env, struct osc_extent *ext,
 818                       int sent, int rc)
 819 {
 820         struct client_obd *cli = osc_cli(ext->oe_obj);
 821         struct osc_async_page *oap;
 822         struct osc_async_page *tmp;
 823         int nr_pages = ext->oe_nr_pages;
 824         int lost_grant = 0;
 825         int blocksize = cli->cl_import->imp_obd->obd_osfs.os_bsize ? : 4096;
 826         __u64 last_off = 0;
 827         int last_count = -1;
 828         ENTRY;
 829
 830         OSC_EXTENT_DUMP(D_CACHE, ext, "extent finished.\n");
 831
 832         ext->oe_rc = rc ?: ext->oe_nr_pages;
 833         EASSERT(ergo(rc == 0, ext->oe_state == OES_RPC), ext);
 834
 835         osc_lru_add_batch(cli, &ext->oe_pages);
 836         list_for_each_entry_safe(oap, tmp, &ext->oe_pages,
 837                                      oap_pending_item) {
 838                 list_del_init(&oap->oap_rpc_item);
 839                 list_del_init(&oap->oap_pending_item);
 840                 if (last_off <= oap->oap_obj_off) {
 841                         last_off = oap->oap_obj_off;
 842                         last_count = oap->oap_count;
 843                 }
 844
 845                 --ext->oe_nr_pages;
 846                 osc_ap_completion(env, cli, oap, sent, rc);
 847         }
 848         EASSERT(ext->oe_nr_pages == 0, ext);
 849
 850         if (!sent) {
 851                 lost_grant = ext->oe_grants;
 852         } else if (blocksize < PAGE_CACHE_SIZE &&
 853                    last_count != PAGE_CACHE_SIZE) {
 854                 /* For short writes we shouldn't count parts of pages that
 855                  * span a whole chunk on the OST side, or our accounting goes
 856                  * wrong.  Should match the code in filter_grant_check. */
 857                 int offset = last_off & ~CFS_PAGE_MASK;
 858                 int count = last_count + (offset & (blocksize - 1));
 859                 int end = (offset + last_count) & (blocksize - 1);
 860                 if (end)
 861                         count += blocksize - end;
 862
 863                 lost_grant = PAGE_CACHE_SIZE - count;
 864         }
 865         if (ext->oe_grants > 0)
 866                 osc_free_grant(cli, nr_pages, lost_grant);
 867
 868         osc_extent_remove(ext);
 869         /* put the refcount for RPC */
 870         osc_extent_put(env, ext);
 871         RETURN(0);
 872 }
 873
 874 static int extent_wait_cb(struct osc_extent *ext, int state)
 875 {
 876         int ret;
 877
 878         osc_object_lock(ext->oe_obj);
 879         ret = ext->oe_state == state;
 880         osc_object_unlock(ext->oe_obj);
 881
 882         return ret;
 883 }
 884
 885 /**
 886  * Wait for the extent's state to become @state.
 887  */
 888 static int osc_extent_wait(const struct lu_env *env, struct osc_extent *ext,
 889                            int state)
 890 {
 891         struct osc_object *obj = ext->oe_obj;
 892         struct l_wait_info lwi = LWI_TIMEOUT_INTR(cfs_time_seconds(600), NULL,
 893                                                   LWI_ON_SIGNAL_NOOP, NULL);
 894         int rc = 0;
 895         ENTRY;
 896
 897         osc_object_lock(obj);
 898         LASSERT(sanity_check_nolock(ext) == 0);
 899         /* `Kick' this extent only if the caller is waiting for it to be
 900          * written out. */
 901         if (state == OES_INV && !ext->oe_urgent && !ext->oe_hp) {
 902                 if (ext->oe_state == OES_ACTIVE) {
 903                         ext->oe_urgent = 1;
 904                 } else if (ext->oe_state == OES_CACHE) {
 905                         ext->oe_urgent = 1;
 906                         osc_extent_hold(ext);
 907                         rc = 1;
 908                 }
 909         }
 910         osc_object_unlock(obj);
 911         if (rc == 1)
 912                 osc_extent_release(env, ext);
 913
 914         /* wait for the extent until its state becomes @state */
 915         rc = l_wait_event(ext->oe_waitq, extent_wait_cb(ext, state), &lwi);
 916         if (rc == -ETIMEDOUT) {
 917                 OSC_EXTENT_DUMP(D_ERROR, ext,
 918                         "%s: wait ext to %d timedout, recovery in progress?\n",
 919                         osc_export(obj)->exp_obd->obd_name, state);
 920
 921                 lwi = LWI_INTR(NULL, NULL);
 922                 rc = l_wait_event(ext->oe_waitq, extent_wait_cb(ext, state),
 923                                   &lwi);
 924         }
 925         if (rc == 0 && ext->oe_rc < 0)
 926                 rc = ext->oe_rc;
 927         RETURN(rc);
 928 }
 929
 930 /**
 931  * Discard pages with index greater than @size. If @ext is overlapped with
 932  * @size, then partial truncate happens.
 933  */
 934 static int osc_extent_truncate(struct osc_extent *ext, pgoff_t trunc_index,
 935                                 bool partial)
 936 {
 937         struct cl_env_nest     nest;
 938         struct lu_env         *env;
 939         struct cl_io          *io;
 940         struct osc_object     *obj = ext->oe_obj;
 941         struct client_obd     *cli = osc_cli(obj);
 942         struct osc_async_page *oap;
 943         struct osc_async_page *tmp;
 944         int                    pages_in_chunk = 0;
 945         int                    ppc_bits    = cli->cl_chunkbits -
 946                                              PAGE_CACHE_SHIFT;
 947         __u64                  trunc_chunk = trunc_index >> ppc_bits;
 948         int                    grants   = 0;
 949         int                    nr_pages = 0;
 950         int                    rc       = 0;
 951         ENTRY;
 952
 953         LASSERT(sanity_check(ext) == 0);
 954         LASSERT(ext->oe_state == OES_TRUNC);
 955         LASSERT(!ext->oe_urgent);
 956
 957         /* Request new lu_env.
 958          * We can't use that env from osc_cache_truncate_start() because
 959          * it's from lov_io_sub and not fully initialized. */
 960         env = cl_env_nested_get(&nest);
 961         io  = &osc_env_info(env)->oti_io;
 962         io->ci_obj = cl_object_top(osc2cl(obj));
 963         rc = cl_io_init(env, io, CIT_MISC, io->ci_obj);
 964         if (rc < 0)
 965                 GOTO(out, rc);
 966
 967         /* discard all pages with index greater then trunc_index */
 968         list_for_each_entry_safe(oap, tmp, &ext->oe_pages,
 969                                      oap_pending_item) {
 970                 pgoff_t index = osc_index(oap2osc(oap));
 971                 struct cl_page  *page = oap2cl_page(oap);
 972
 973                 LASSERT(list_empty(&oap->oap_rpc_item));
 974
 975                 /* only discard the pages with their index greater than
 976                  * trunc_index, and ... */
 977                 if (index < trunc_index ||
 978                     (index == trunc_index && partial)) {
 979                         /* accounting how many pages remaining in the chunk
 980                          * so that we can calculate grants correctly. */
 981                         if (index >> ppc_bits == trunc_chunk)
 982                                 ++pages_in_chunk;
 983                         continue;
 984                 }
 985
 986                 list_del_init(&oap->oap_pending_item);
 987
 988                 cl_page_get(page);
 989                 lu_ref_add(&page->cp_reference, "truncate", current);
 990
 991                 if (cl_page_own(env, io, page) == 0) {
 992                         cl_page_discard(env, io, page);
 993                         cl_page_disown(env, io, page);
 994                 } else {
 995                         LASSERT(page->cp_state == CPS_FREEING);
 996                         LASSERT(0);
 997                 }
 998
 999                 lu_ref_del(&page->cp_reference, "truncate", current);
1000                 cl_page_put(env, page);
1001
1002                 --ext->oe_nr_pages;
1003                 ++nr_pages;
1004         }
1005         EASSERTF(ergo(ext->oe_start >= trunc_index + !!partial,
1006                       ext->oe_nr_pages == 0),
1007                 ext, "trunc_index %lu, partial %d\n", trunc_index, partial);
1008
1009         osc_object_lock(obj);
1010         if (ext->oe_nr_pages == 0) {
1011                 LASSERT(pages_in_chunk == 0);
1012                 grants = ext->oe_grants;
1013                 ext->oe_grants = 0;
1014         } else { /* calculate how many grants we can free */
1015                 int     chunks = (ext->oe_end >> ppc_bits) - trunc_chunk;
1016                 pgoff_t last_index;
1017
1018
1019                 /* if there is no pages in this chunk, we can also free grants
1020                  * for the last chunk */
1021                 if (pages_in_chunk == 0) {
1022                         /* if this is the 1st chunk and no pages in this chunk,
1023                          * ext->oe_nr_pages must be zero, so we should be in
1024                          * the other if-clause. */
1025                         LASSERT(trunc_chunk > 0);
1026                         --trunc_chunk;
1027                         ++chunks;
1028                 }
1029
1030                 /* this is what we can free from this extent */
1031                 grants          = chunks << cli->cl_chunkbits;
1032                 ext->oe_grants -= grants;
1033                 last_index      = ((trunc_chunk + 1) << ppc_bits) - 1;
1034                 ext->oe_end     = min(last_index, ext->oe_max_end);
1035                 LASSERT(ext->oe_end >= ext->oe_start);
1036                 LASSERT(ext->oe_grants > 0);
1037         }
1038         osc_object_unlock(obj);
1039
1040         if (grants > 0 || nr_pages > 0)
1041                 osc_free_grant(cli, nr_pages, grants);
1042
1043 out:
1044         cl_io_fini(env, io);
1045         cl_env_nested_put(&nest, env);
1046         RETURN(rc);
1047 }
1048
1049 /**
1050  * This function is used to make the extent prepared for transfer.
1051  * A race with flusing page - ll_writepage() has to be handled cautiously.
1052  */
1053 static int osc_extent_make_ready(const struct lu_env *env,
1054                                  struct osc_extent *ext)
1055 {
1056         struct osc_async_page *oap;
1057         struct osc_async_page *last = NULL;
1058         struct osc_object *obj = ext->oe_obj;
1059         int page_count = 0;
1060         int rc;
1061         ENTRY;
1062
1063         /* we're going to grab page lock, so object lock must not be taken. */
1064         LASSERT(sanity_check(ext) == 0);
1065         /* in locking state, any process should not touch this extent. */
1066         EASSERT(ext->oe_state == OES_LOCKING, ext);
1067         EASSERT(ext->oe_owner != NULL, ext);
1068
1069         OSC_EXTENT_DUMP(D_CACHE, ext, "make ready\n");
1070
1071         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
1072                 ++page_count;
1073                 if (last == NULL || last->oap_obj_off < oap->oap_obj_off)
1074                         last = oap;
1075
1076                 /* checking ASYNC_READY is race safe */
1077                 if ((oap->oap_async_flags & ASYNC_READY) != 0)
1078                         continue;
1079
1080                 rc = osc_make_ready(env, oap, OBD_BRW_WRITE);
1081                 switch (rc) {
1082                 case 0:
1083                         spin_lock(&oap->oap_lock);
1084                         oap->oap_async_flags |= ASYNC_READY;
1085                         spin_unlock(&oap->oap_lock);
1086                         break;
1087                 case -EALREADY:
1088                         LASSERT((oap->oap_async_flags & ASYNC_READY) != 0);
1089                         break;
1090                 default:
1091                         LASSERTF(0, "unknown return code: %d\n", rc);
1092                 }
1093         }
1094
1095         LASSERT(page_count == ext->oe_nr_pages);
1096         LASSERT(last != NULL);
1097         /* the last page is the only one we need to refresh its count by
1098          * the size of file. */
1099         if (!(last->oap_async_flags & ASYNC_COUNT_STABLE)) {
1100                 last->oap_count = osc_refresh_count(env, last, OBD_BRW_WRITE);
1101                 LASSERT(last->oap_count > 0);
1102                 LASSERT(last->oap_page_off + last->oap_count <= PAGE_CACHE_SIZE);
1103                 spin_lock(&last->oap_lock);
1104                 last->oap_async_flags |= ASYNC_COUNT_STABLE;
1105                 spin_unlock(&last->oap_lock);
1106         }
1107
1108         /* for the rest of pages, we don't need to call osf_refresh_count()
1109          * because it's known they are not the last page */
1110         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
1111                 if (!(oap->oap_async_flags & ASYNC_COUNT_STABLE)) {
1112                         oap->oap_count = PAGE_CACHE_SIZE - oap->oap_page_off;
1113                         spin_lock(&oap->oap_lock);
1114                         oap->oap_async_flags |= ASYNC_COUNT_STABLE;
1115                         spin_unlock(&oap->oap_lock);
1116                 }
1117         }
1118
1119         osc_object_lock(obj);
1120         osc_extent_state_set(ext, OES_RPC);
1121         osc_object_unlock(obj);
1122         /* get a refcount for RPC. */
1123         osc_extent_get(ext);
1124
1125         RETURN(0);
1126 }
1127
1128 /**
1129  * Quick and simple version of osc_extent_find(). This function is frequently
1130  * called to expand the extent for the same IO. To expand the extent, the
1131  * page index must be in the same or next chunk of ext->oe_end.
1132  */
1133 static int osc_extent_expand(struct osc_extent *ext, pgoff_t index, int *grants)
1134 {
1135         struct osc_object *obj = ext->oe_obj;
1136         struct client_obd *cli = osc_cli(obj);
1137         struct osc_extent *next;
1138         int ppc_bits = cli->cl_chunkbits - PAGE_CACHE_SHIFT;
1139         pgoff_t chunk = index >> ppc_bits;
1140         pgoff_t end_chunk;
1141         pgoff_t end_index;
1142         int chunksize = 1 << cli->cl_chunkbits;
1143         int rc = 0;
1144         ENTRY;
1145
1146         LASSERT(ext->oe_max_end >= index && ext->oe_start <= index);
1147         osc_object_lock(obj);
1148         LASSERT(sanity_check_nolock(ext) == 0);
1149         end_chunk = ext->oe_end >> ppc_bits;
1150         if (chunk > end_chunk + 1)
1151                 GOTO(out, rc = -ERANGE);
1152
1153         if (end_chunk >= chunk)
1154                 GOTO(out, rc = 0);
1155
1156         LASSERT(end_chunk + 1 == chunk);
1157         /* try to expand this extent to cover @index */
1158         end_index = min(ext->oe_max_end, ((chunk + 1) << ppc_bits) - 1);
1159
1160         next = next_extent(ext);
1161         if (next != NULL && next->oe_start <= end_index)
1162                 /* complex mode - overlapped with the next extent,
1163                  * this case will be handled by osc_extent_find() */
1164                 GOTO(out, rc = -EAGAIN);
1165
1166         ext->oe_end = end_index;
1167         ext->oe_grants += chunksize;
1168         *grants -= chunksize;
1169         LASSERT(*grants >= 0);
1170         EASSERTF(osc_extent_is_overlapped(obj, ext) == 0, ext,
1171                  "overlapped after expanding for %lu.\n", index);
1172         EXIT;
1173
1174 out:
1175         osc_object_unlock(obj);
1176         RETURN(rc);
1177 }
1178
1179 static void osc_extent_tree_dump0(int level, struct osc_object *obj,
1180                                   const char *func, int line)
1181 {
1182         struct osc_extent *ext;
1183         int cnt;
1184
1185         CDEBUG(level, "Dump object %p extents at %s:%d, mppr: %u.\n",
1186                obj, func, line, osc_cli(obj)->cl_max_pages_per_rpc);
1187
1188         /* osc_object_lock(obj); */
1189         cnt = 1;
1190         for (ext = first_extent(obj); ext != NULL; ext = next_extent(ext))
1191                 OSC_EXTENT_DUMP(level, ext, "in tree %d.\n", cnt++);
1192
1193         cnt = 1;
1194         list_for_each_entry(ext, &obj->oo_hp_exts, oe_link)
1195                 OSC_EXTENT_DUMP(level, ext, "hp %d.\n", cnt++);
1196
1197         cnt = 1;
1198         list_for_each_entry(ext, &obj->oo_urgent_exts, oe_link)
1199                 OSC_EXTENT_DUMP(level, ext, "urgent %d.\n", cnt++);
1200
1201         cnt = 1;
1202         list_for_each_entry(ext, &obj->oo_reading_exts, oe_link)
1203                 OSC_EXTENT_DUMP(level, ext, "reading %d.\n", cnt++);
1204         /* osc_object_unlock(obj); */
1205 }
1206
1207 /* ------------------ osc extent end ------------------ */
1208
1209 static inline int osc_is_ready(struct osc_object *osc)
1210 {
1211         return !list_empty(&osc->oo_ready_item) ||
1212                !list_empty(&osc->oo_hp_ready_item);
1213 }
1214
1215 #define OSC_IO_DEBUG(OSC, STR, args...)                                        \
1216         CDEBUG(D_CACHE, "obj %p ready %d|%c|%c wr %d|%c|%c rd %d|%c " STR,     \
1217                (OSC), osc_is_ready(OSC),                                       \
1218                list_empty_marker(&(OSC)->oo_hp_ready_item),                    \
1219                list_empty_marker(&(OSC)->oo_ready_item),                       \
1220                atomic_read(&(OSC)->oo_nr_writes),                              \
1221                list_empty_marker(&(OSC)->oo_hp_exts),                          \
1222                list_empty_marker(&(OSC)->oo_urgent_exts),                      \
1223                atomic_read(&(OSC)->oo_nr_reads),                               \
1224                list_empty_marker(&(OSC)->oo_reading_exts),                     \
1225                ##args)
1226
1227 static int osc_make_ready(const struct lu_env *env, struct osc_async_page *oap,
1228                           int cmd)
1229 {
1230         struct osc_page *opg  = oap2osc_page(oap);
1231         struct cl_page  *page = oap2cl_page(oap);
1232         int result;
1233
1234         LASSERT(cmd == OBD_BRW_WRITE); /* no cached reads */
1235
1236         ENTRY;
1237         result = cl_page_make_ready(env, page, CRT_WRITE);
1238         if (result == 0)
1239                 opg->ops_submit_time = cfs_time_current();
1240         RETURN(result);
1241 }
1242
1243 static int osc_refresh_count(const struct lu_env *env,
1244                              struct osc_async_page *oap, int cmd)
1245 {
1246         struct osc_page  *opg = oap2osc_page(oap);
1247         pgoff_t index = osc_index(oap2osc(oap));
1248         struct cl_object *obj;
1249         struct cl_attr   *attr = &osc_env_info(env)->oti_attr;
1250
1251         int result;
1252         loff_t kms;
1253
1254         /* readpage queues with _COUNT_STABLE, shouldn't get here. */
1255         LASSERT(!(cmd & OBD_BRW_READ));
1256         LASSERT(opg != NULL);
1257         obj = opg->ops_cl.cpl_obj;
1258
1259         cl_object_attr_lock(obj);
1260         result = cl_object_attr_get(env, obj, attr);
1261         cl_object_attr_unlock(obj);
1262         if (result < 0)
1263                 return result;
1264         kms = attr->cat_kms;
1265         if (cl_offset(obj, index) >= kms)
1266                 /* catch race with truncate */
1267                 return 0;
1268         else if (cl_offset(obj, index + 1) > kms)
1269                 /* catch sub-page write at end of file */
1270                 return kms % PAGE_CACHE_SIZE;
1271         else
1272                 return PAGE_CACHE_SIZE;
1273 }
1274
1275 static int osc_completion(const struct lu_env *env, struct osc_async_page *oap,
1276                           int cmd, int rc)
1277 {
1278         struct osc_page   *opg  = oap2osc_page(oap);
1279         struct cl_page    *page = oap2cl_page(oap);
1280         struct osc_object *obj  = cl2osc(opg->ops_cl.cpl_obj);
1281         enum cl_req_type   crt;
1282         int srvlock;
1283
1284         ENTRY;
1285
1286         cmd &= ~OBD_BRW_NOQUOTA;
1287         LASSERTF(equi(page->cp_state == CPS_PAGEIN,  cmd == OBD_BRW_READ),
1288                  "cp_state:%u, cmd:%d\n", page->cp_state, cmd);
1289         LASSERTF(equi(page->cp_state == CPS_PAGEOUT, cmd == OBD_BRW_WRITE),
1290                 "cp_state:%u, cmd:%d\n", page->cp_state, cmd);
1291         LASSERT(opg->ops_transfer_pinned);
1292
1293         /*
1294          * page->cp_req can be NULL if io submission failed before
1295          * cl_req was allocated.
1296          */
1297         if (page->cp_req != NULL)
1298                 cl_req_page_done(env, page);
1299         LASSERT(page->cp_req == NULL);
1300
1301         crt = cmd == OBD_BRW_READ ? CRT_READ : CRT_WRITE;
1302         /* Clear opg->ops_transfer_pinned before VM lock is released. */
1303         opg->ops_transfer_pinned = 0;
1304
1305         spin_lock(&obj->oo_seatbelt);
1306         LASSERT(opg->ops_submitter != NULL);
1307         LASSERT(!list_empty(&opg->ops_inflight));
1308         list_del_init(&opg->ops_inflight);
1309         opg->ops_submitter = NULL;
1310         spin_unlock(&obj->oo_seatbelt);
1311
1312         opg->ops_submit_time = 0;
1313         srvlock = oap->oap_brw_flags & OBD_BRW_SRVLOCK;
1314
1315         /* statistic */
1316         if (rc == 0 && srvlock) {
1317                 struct lu_device *ld    = opg->ops_cl.cpl_obj->co_lu.lo_dev;
1318                 struct osc_stats *stats = &lu2osc_dev(ld)->od_stats;
1319                 int bytes = oap->oap_count;
1320
1321                 if (crt == CRT_READ)
1322                         stats->os_lockless_reads += bytes;
1323                 else
1324                         stats->os_lockless_writes += bytes;
1325         }
1326
1327         /*
1328          * This has to be the last operation with the page, as locks are
1329          * released in cl_page_completion() and nothing except for the
1330          * reference counter protects page from concurrent reclaim.
1331          */
1332         lu_ref_del(&page->cp_reference, "transfer", page);
1333
1334         cl_page_completion(env, page, crt, rc);
1335
1336         RETURN(0);
1337 }
1338
1339 #define OSC_DUMP_GRANT(lvl, cli, fmt, args...) do {                     \
1340         struct client_obd *__tmp = (cli);                               \
1341         CDEBUG(lvl, "%s: grant { dirty: %ld/%ld dirty_pages: %ld/%lu "  \
1342                "dropped: %ld avail: %ld, reserved: %ld, flight: %d }"   \
1343                "lru {in list: %ld, left: %ld, waiters: %d }"fmt"\n",    \
1344                __tmp->cl_import->imp_obd->obd_name,                     \
1345                __tmp->cl_dirty_pages, __tmp->cl_dirty_max_pages,        \
1346                atomic_long_read(&obd_dirty_pages), obd_max_dirty_pages, \
1347                __tmp->cl_lost_grant, __tmp->cl_avail_grant,             \
1348                __tmp->cl_reserved_grant, __tmp->cl_w_in_flight,         \
1349                atomic_long_read(&__tmp->cl_lru_in_list),                \
1350                atomic_long_read(&__tmp->cl_lru_busy),                   \
1351                atomic_read(&__tmp->cl_lru_shrinkers), ##args);          \
1352 } while (0)
1353
1354 /* caller must hold loi_list_lock */
1355 static void osc_consume_write_grant(struct client_obd *cli,
1356                                     struct brw_page *pga)
1357 {
1358         assert_spin_locked(&cli->cl_loi_list_lock.lock);
1359         LASSERT(!(pga->flag & OBD_BRW_FROM_GRANT));
1360         atomic_long_inc(&obd_dirty_pages);
1361         cli->cl_dirty_pages++;
1362         pga->flag |= OBD_BRW_FROM_GRANT;
1363         CDEBUG(D_CACHE, "using %lu grant credits for brw %p page %p\n",
1364                PAGE_CACHE_SIZE, pga, pga->pg);
1365         osc_update_next_shrink(cli);
1366 }
1367
1368 /* the companion to osc_consume_write_grant, called when a brw has completed.
1369  * must be called with the loi lock held. */
1370 static void osc_release_write_grant(struct client_obd *cli,
1371                                     struct brw_page *pga)
1372 {
1373         ENTRY;
1374
1375         assert_spin_locked(&cli->cl_loi_list_lock.lock);
1376         if (!(pga->flag & OBD_BRW_FROM_GRANT)) {
1377                 EXIT;
1378                 return;
1379         }
1380
1381         pga->flag &= ~OBD_BRW_FROM_GRANT;
1382         atomic_long_dec(&obd_dirty_pages);
1383         cli->cl_dirty_pages--;
1384         if (pga->flag & OBD_BRW_NOCACHE) {
1385                 pga->flag &= ~OBD_BRW_NOCACHE;
1386                 atomic_long_dec(&obd_dirty_transit_pages);
1387                 cli->cl_dirty_transit--;
1388         }
1389         EXIT;
1390 }
1391
1392 /**
1393  * To avoid sleeping with object lock held, it's good for us allocate enough
1394  * grants before entering into critical section.
1395  *
1396  * client_obd_list_lock held by caller
1397  */
1398 static int osc_reserve_grant(struct client_obd *cli, unsigned int bytes)
1399 {
1400         int rc = -EDQUOT;
1401
1402         if (cli->cl_avail_grant >= bytes) {
1403                 cli->cl_avail_grant    -= bytes;
1404                 cli->cl_reserved_grant += bytes;
1405                 rc = 0;
1406         }
1407         return rc;
1408 }
1409
1410 static void __osc_unreserve_grant(struct client_obd *cli,
1411                                   unsigned int reserved, unsigned int unused)
1412 {
1413         /* it's quite normal for us to get more grant than reserved.
1414          * Thinking about a case that two extents merged by adding a new
1415          * chunk, we can save one extent tax. If extent tax is greater than
1416          * one chunk, we can save more grant by adding a new chunk */
1417         cli->cl_reserved_grant -= reserved;
1418         if (unused > reserved) {
1419                 cli->cl_avail_grant += reserved;
1420                 cli->cl_lost_grant  += unused - reserved;
1421         } else {
1422                 cli->cl_avail_grant += unused;
1423         }
1424 }
1425
1426 void osc_unreserve_grant(struct client_obd *cli,
1427                          unsigned int reserved, unsigned int unused)
1428 {
1429         client_obd_list_lock(&cli->cl_loi_list_lock);
1430         __osc_unreserve_grant(cli, reserved, unused);
1431         if (unused > 0)
1432                 osc_wake_cache_waiters(cli);
1433         client_obd_list_unlock(&cli->cl_loi_list_lock);
1434 }
1435
1436 /**
1437  * Free grant after IO is finished or canceled.
1438  *
1439  * @lost_grant is used to remember how many grants we have allocated but not
1440  * used, we should return these grants to OST. There're two cases where grants
1441  * can be lost:
1442  * 1. truncate;
1443  * 2. blocksize at OST is less than PAGE_CACHE_SIZE and a partial page was
1444  *    written. In this case OST may use less chunks to serve this partial
1445  *    write. OSTs don't actually know the page size on the client side. so
1446  *    clients have to calculate lost grant by the blocksize on the OST.
1447  *    See filter_grant_check() for details.
1448  */
1449 static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
1450                            unsigned int lost_grant)
1451 {
1452         int grant = (1 << cli->cl_chunkbits) + cli->cl_extent_tax;
1453
1454         client_obd_list_lock(&cli->cl_loi_list_lock);
1455         atomic_long_sub(nr_pages, &obd_dirty_pages);
1456         cli->cl_dirty_pages -= nr_pages;
1457         cli->cl_lost_grant += lost_grant;
1458         if (cli->cl_avail_grant < grant && cli->cl_lost_grant >= grant) {
1459                 /* borrow some grant from truncate to avoid the case that
1460                  * truncate uses up all avail grant */
1461                 cli->cl_lost_grant -= grant;
1462                 cli->cl_avail_grant += grant;
1463         }
1464         osc_wake_cache_waiters(cli);
1465         client_obd_list_unlock(&cli->cl_loi_list_lock);
1466         CDEBUG(D_CACHE, "lost %u grant: %lu avail: %lu dirty: %lu\n",
1467                lost_grant, cli->cl_lost_grant,
1468                cli->cl_avail_grant, cli->cl_dirty_pages << PAGE_CACHE_SHIFT);
1469 }
1470
1471 /**
1472  * The companion to osc_enter_cache(), called when @oap is no longer part of
1473  * the dirty accounting due to error.
1474  */
1475 static void osc_exit_cache(struct client_obd *cli, struct osc_async_page *oap)
1476 {
1477         client_obd_list_lock(&cli->cl_loi_list_lock);
1478         osc_release_write_grant(cli, &oap->oap_brw_page);
1479         client_obd_list_unlock(&cli->cl_loi_list_lock);
1480 }
1481
1482 /**
1483  * Non-blocking version of osc_enter_cache() that consumes grant only when it
1484  * is available.
1485  */
1486 static int osc_enter_cache_try(struct client_obd *cli,
1487                                struct osc_async_page *oap,
1488                                int bytes, int transient)
1489 {
1490         int rc;
1491
1492         OSC_DUMP_GRANT(D_CACHE, cli, "need:%d.\n", bytes);
1493
1494         rc = osc_reserve_grant(cli, bytes);
1495         if (rc < 0)
1496                 return 0;
1497
1498         if (cli->cl_dirty_pages < cli->cl_dirty_max_pages &&
1499             1 + atomic_long_read(&obd_dirty_pages) <= obd_max_dirty_pages) {
1500                 osc_consume_write_grant(cli, &oap->oap_brw_page);
1501                 if (transient) {
1502                         cli->cl_dirty_transit++;
1503                         atomic_long_inc(&obd_dirty_transit_pages);
1504                         oap->oap_brw_flags |= OBD_BRW_NOCACHE;
1505                 }
1506                 rc = 1;
1507         } else {
1508                 __osc_unreserve_grant(cli, bytes, bytes);
1509                 rc = 0;
1510         }
1511         return rc;
1512 }
1513
1514 static int ocw_granted(struct client_obd *cli, struct osc_cache_waiter *ocw)
1515 {
1516         int rc;
1517         client_obd_list_lock(&cli->cl_loi_list_lock);
1518         rc = list_empty(&ocw->ocw_entry);
1519         client_obd_list_unlock(&cli->cl_loi_list_lock);
1520         return rc;
1521 }
1522
1523 /**
1524  * The main entry to reserve dirty page accounting. Usually the grant reserved
1525  * in this function will be freed in bulk in osc_free_grant() unless it fails
1526  * to add osc cache, in that case, it will be freed in osc_exit_cache().
1527  *
1528  * The process will be put into sleep if it's already run out of grant.
1529  */
1530 static int osc_enter_cache(const struct lu_env *env, struct client_obd *cli,
1531                            struct osc_async_page *oap, int bytes)
1532 {
1533         struct osc_object *osc = oap->oap_obj;
1534         struct lov_oinfo  *loi = osc->oo_oinfo;
1535         struct osc_cache_waiter ocw;
1536         struct l_wait_info lwi = LWI_TIMEOUT_INTR(cfs_time_seconds(600), NULL,
1537                                                   LWI_ON_SIGNAL_NOOP, NULL);
1538         int rc = -EDQUOT;
1539         ENTRY;
1540
1541         OSC_DUMP_GRANT(D_CACHE, cli, "need:%d.\n", bytes);
1542
1543         client_obd_list_lock(&cli->cl_loi_list_lock);
1544
1545         /* force the caller to try sync io.  this can jump the list
1546          * of queued writes and create a discontiguous rpc stream */
1547         if (OBD_FAIL_CHECK(OBD_FAIL_OSC_NO_GRANT) ||
1548             cli->cl_dirty_max_pages == 0 ||
1549             cli->cl_ar.ar_force_sync || loi->loi_ar.ar_force_sync)
1550                 GOTO(out, rc = -EDQUOT);
1551
1552         /* Hopefully normal case - cache space and write credits available */
1553         if (osc_enter_cache_try(cli, oap, bytes, 0))
1554                 GOTO(out, rc = 0);
1555
1556         /* We can get here for two reasons: too many dirty pages in cache, or
1557          * run out of grants. In both cases we should write dirty pages out.
1558          * Adding a cache waiter will trigger urgent write-out no matter what
1559          * RPC size will be.
1560          * The exiting condition is no avail grants and no dirty pages caching,
1561          * that really means there is no space on the OST. */
1562         init_waitqueue_head(&ocw.ocw_waitq);
1563         ocw.ocw_oap   = oap;
1564         ocw.ocw_grant = bytes;
1565         while (cli->cl_dirty_pages > 0 || cli->cl_w_in_flight > 0) {
1566                 list_add_tail(&ocw.ocw_entry, &cli->cl_cache_waiters);
1567                 ocw.ocw_rc = 0;
1568                 client_obd_list_unlock(&cli->cl_loi_list_lock);
1569
1570                 osc_io_unplug_async(env, cli, NULL);
1571
1572                 CDEBUG(D_CACHE, "%s: sleeping for cache space @ %p for %p\n",
1573                        cli->cl_import->imp_obd->obd_name, &ocw, oap);
1574
1575                 rc = l_wait_event(ocw.ocw_waitq, ocw_granted(cli, &ocw), &lwi);
1576
1577                 client_obd_list_lock(&cli->cl_loi_list_lock);
1578
1579                 /* l_wait_event is interrupted by signal, or timed out */
1580                 if (rc < 0) {
1581                         switch (rc) {
1582                         case -ETIMEDOUT:
1583                                 OSC_DUMP_GRANT(D_ERROR, cli,
1584                                                 "try to reserve %d.\n", bytes);
1585                                 osc_extent_tree_dump(D_ERROR, osc);
1586                                 rc = -EDQUOT;
1587                                 break;
1588                         case -EINTR:
1589                                 /* Ensures restartability - LU-3581 */
1590                                 rc = -ERESTARTSYS;
1591                                 break;
1592                         default:
1593                                 CDEBUG(D_CACHE, "%s: event for cache space @"
1594                                        " %p never arrived due to %d\n",
1595                                        cli->cl_import->imp_obd->obd_name,
1596                                        &ocw, rc);
1597                                 break;
1598                         }
1599                         list_del_init(&ocw.ocw_entry);
1600                         GOTO(out, rc);
1601                 }
1602
1603                 LASSERT(list_empty(&ocw.ocw_entry));
1604                 rc = ocw.ocw_rc;
1605
1606                 if (rc != -EDQUOT)
1607                         GOTO(out, rc);
1608                 if (osc_enter_cache_try(cli, oap, bytes, 0))
1609                         GOTO(out, rc = 0);
1610         }
1611         EXIT;
1612 out:
1613         client_obd_list_unlock(&cli->cl_loi_list_lock);
1614         OSC_DUMP_GRANT(D_CACHE, cli, "returned %d.\n", rc);
1615         RETURN(rc);
1616 }
1617
1618 /* caller must hold loi_list_lock */
1619 void osc_wake_cache_waiters(struct client_obd *cli)
1620 {
1621         struct list_head *l, *tmp;
1622         struct osc_cache_waiter *ocw;
1623
1624         ENTRY;
1625         list_for_each_safe(l, tmp, &cli->cl_cache_waiters) {
1626                 ocw = list_entry(l, struct osc_cache_waiter, ocw_entry);
1627                 list_del_init(&ocw->ocw_entry);
1628
1629                 ocw->ocw_rc = -EDQUOT;
1630                 /* we can't dirty more */
1631                 if ((cli->cl_dirty_pages  >= cli->cl_dirty_max_pages) ||
1632                     (1 + atomic_long_read(&obd_dirty_pages) >
1633                      obd_max_dirty_pages)) {
1634                         CDEBUG(D_CACHE, "no dirty room: dirty: %ld "
1635                                "osc max %ld, sys max %ld\n",
1636                                cli->cl_dirty_pages, cli->cl_dirty_max_pages,
1637                                obd_max_dirty_pages);
1638                         goto wakeup;
1639                 }
1640
1641                 ocw->ocw_rc = 0;
1642                 if (!osc_enter_cache_try(cli, ocw->ocw_oap, ocw->ocw_grant, 0))
1643                         ocw->ocw_rc = -EDQUOT;
1644
1645 wakeup:
1646                 CDEBUG(D_CACHE, "wake up %p for oap %p, avail grant %ld, %d\n",
1647                        ocw, ocw->ocw_oap, cli->cl_avail_grant, ocw->ocw_rc);
1648
1649                 wake_up(&ocw->ocw_waitq);
1650         }
1651
1652         EXIT;
1653 }
1654
1655 static int osc_max_rpc_in_flight(struct client_obd *cli, struct osc_object *osc)
1656 {
1657         int hprpc = !!list_empty(&osc->oo_hp_exts);
1658         return rpcs_in_flight(cli) >= cli->cl_max_rpcs_in_flight + hprpc;
1659 }
1660
1661 /* This maintains the lists of pending pages to read/write for a given object
1662  * (lop).  This is used by osc_check_rpcs->osc_next_obj() and osc_list_maint()
1663  * to quickly find objects that are ready to send an RPC. */
1664 static int osc_makes_rpc(struct client_obd *cli, struct osc_object *osc,
1665                          int cmd)
1666 {
1667         int invalid_import = 0;
1668         ENTRY;
1669
1670         /* if we have an invalid import we want to drain the queued pages
1671          * by forcing them through rpcs that immediately fail and complete
1672          * the pages.  recovery relies on this to empty the queued pages
1673          * before canceling the locks and evicting down the llite pages */
1674         if ((cli->cl_import == NULL || cli->cl_import->imp_invalid))
1675                 invalid_import = 1;
1676
1677         if (cmd & OBD_BRW_WRITE) {
1678                 if (atomic_read(&osc->oo_nr_writes) == 0)
1679                         RETURN(0);
1680                 if (invalid_import) {
1681                         CDEBUG(D_CACHE, "invalid import forcing RPC\n");
1682                         RETURN(1);
1683                 }
1684                 if (!list_empty(&osc->oo_hp_exts)) {
1685                         CDEBUG(D_CACHE, "high prio request forcing RPC\n");
1686                         RETURN(1);
1687                 }
1688                 if (!list_empty(&osc->oo_urgent_exts)) {
1689                         CDEBUG(D_CACHE, "urgent request forcing RPC\n");
1690                         RETURN(1);
1691                 }
1692                 /* trigger a write rpc stream as long as there are dirtiers
1693                  * waiting for space.  as they're waiting, they're not going to
1694                  * create more pages to coalesce with what's waiting.. */
1695                 if (!list_empty(&cli->cl_cache_waiters)) {
1696                         CDEBUG(D_CACHE, "cache waiters forcing RPC\n");
1697                         RETURN(1);
1698                 }
1699                 if (atomic_read(&osc->oo_nr_writes) >=
1700                     cli->cl_max_pages_per_rpc)
1701                         RETURN(1);
1702         } else {
1703                 if (atomic_read(&osc->oo_nr_reads) == 0)
1704                         RETURN(0);
1705                 if (invalid_import) {
1706                         CDEBUG(D_CACHE, "invalid import forcing RPC\n");
1707                         RETURN(1);
1708                 }
1709                 /* all read are urgent. */
1710                 if (!list_empty(&osc->oo_reading_exts))
1711                         RETURN(1);
1712         }
1713
1714         RETURN(0);
1715 }
1716
1717 static void osc_update_pending(struct osc_object *obj, int cmd, int delta)
1718 {
1719         struct client_obd *cli = osc_cli(obj);
1720         if (cmd & OBD_BRW_WRITE) {
1721                 atomic_add(delta, &obj->oo_nr_writes);
1722                 atomic_add(delta, &cli->cl_pending_w_pages);
1723                 LASSERT(atomic_read(&obj->oo_nr_writes) >= 0);
1724         } else {
1725                 atomic_add(delta, &obj->oo_nr_reads);
1726                 atomic_add(delta, &cli->cl_pending_r_pages);
1727                 LASSERT(atomic_read(&obj->oo_nr_reads) >= 0);
1728         }
1729         OSC_IO_DEBUG(obj, "update pending cmd %d delta %d.\n", cmd, delta);
1730 }
1731
1732 static int osc_makes_hprpc(struct osc_object *obj)
1733 {
1734         return !list_empty(&obj->oo_hp_exts);
1735 }
1736
1737 static void on_list(struct list_head *item, struct list_head *list,
1738                     int should_be_on)
1739 {
1740         if (list_empty(item) && should_be_on)
1741                 list_add_tail(item, list);
1742         else if (!list_empty(item) && !should_be_on)
1743                 list_del_init(item);
1744 }
1745
1746 /* maintain the osc's cli list membership invariants so that osc_send_oap_rpc
1747  * can find pages to build into rpcs quickly */
1748 static int __osc_list_maint(struct client_obd *cli, struct osc_object *osc)
1749 {
1750         if (osc_makes_hprpc(osc)) {
1751                 /* HP rpc */
1752                 on_list(&osc->oo_ready_item, &cli->cl_loi_ready_list, 0);
1753                 on_list(&osc->oo_hp_ready_item, &cli->cl_loi_hp_ready_list, 1);
1754         } else {
1755                 on_list(&osc->oo_hp_ready_item, &cli->cl_loi_hp_ready_list, 0);
1756                 on_list(&osc->oo_ready_item, &cli->cl_loi_ready_list,
1757                         osc_makes_rpc(cli, osc, OBD_BRW_WRITE) ||
1758                         osc_makes_rpc(cli, osc, OBD_BRW_READ));
1759         }
1760
1761         on_list(&osc->oo_write_item, &cli->cl_loi_write_list,
1762                 atomic_read(&osc->oo_nr_writes) > 0);
1763
1764         on_list(&osc->oo_read_item, &cli->cl_loi_read_list,
1765                 atomic_read(&osc->oo_nr_reads) > 0);
1766
1767         return osc_is_ready(osc);
1768 }
1769
1770 static int osc_list_maint(struct client_obd *cli, struct osc_object *osc)
1771 {
1772         int is_ready;
1773
1774         client_obd_list_lock(&cli->cl_loi_list_lock);
1775         is_ready = __osc_list_maint(cli, osc);
1776         client_obd_list_unlock(&cli->cl_loi_list_lock);
1777
1778         return is_ready;
1779 }
1780
1781 /* this is trying to propogate async writeback errors back up to the
1782  * application.  As an async write fails we record the error code for later if
1783  * the app does an fsync.  As long as errors persist we force future rpcs to be
1784  * sync so that the app can get a sync error and break the cycle of queueing
1785  * pages for which writeback will fail. */
1786 static void osc_process_ar(struct osc_async_rc *ar, __u64 xid,
1787                            int rc)
1788 {
1789         if (rc) {
1790                 if (!ar->ar_rc)
1791                         ar->ar_rc = rc;
1792
1793                 ar->ar_force_sync = 1;
1794                 ar->ar_min_xid = ptlrpc_sample_next_xid();
1795                 return;
1796
1797         }
1798
1799         if (ar->ar_force_sync && (xid >= ar->ar_min_xid))
1800                 ar->ar_force_sync = 0;
1801 }
1802
1803 /* this must be called holding the loi list lock to give coverage to exit_cache,
1804  * async_flag maintenance, and oap_request */
1805 static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
1806                               struct osc_async_page *oap, int sent, int rc)
1807 {
1808         struct osc_object *osc = oap->oap_obj;
1809         struct lov_oinfo  *loi = osc->oo_oinfo;
1810         __u64 xid = 0;
1811
1812         ENTRY;
1813         if (oap->oap_request != NULL) {
1814                 xid = ptlrpc_req_xid(oap->oap_request);
1815                 ptlrpc_req_finished(oap->oap_request);
1816                 oap->oap_request = NULL;
1817         }
1818
1819         /* As the transfer for this page is being done, clear the flags */
1820         spin_lock(&oap->oap_lock);
1821         oap->oap_async_flags = 0;
1822         spin_unlock(&oap->oap_lock);
1823         oap->oap_interrupted = 0;
1824
1825         if (oap->oap_cmd & OBD_BRW_WRITE && xid > 0) {
1826                 client_obd_list_lock(&cli->cl_loi_list_lock);
1827                 osc_process_ar(&cli->cl_ar, xid, rc);
1828                 osc_process_ar(&loi->loi_ar, xid, rc);
1829                 client_obd_list_unlock(&cli->cl_loi_list_lock);
1830         }
1831
1832         rc = osc_completion(env, oap, oap->oap_cmd, rc);
1833         if (rc)
1834                 CERROR("completion on oap %p obj %p returns %d.\n",
1835                        oap, osc, rc);
1836
1837         EXIT;
1838 }
1839
1840 /**
1841  * Try to add extent to one RPC. We need to think about the following things:
1842  * - # of pages must not be over max_pages_per_rpc
1843  * - extent must be compatible with previous ones
1844  */
1845 static int try_to_add_extent_for_io(struct client_obd *cli,
1846                                     struct osc_extent *ext,
1847                                     struct list_head *rpclist,
1848                                     int *pc, unsigned int *max_pages)
1849 {
1850         struct osc_extent *tmp;
1851         struct osc_async_page *oap = list_first_entry(&ext->oe_pages,
1852                                                       struct osc_async_page,
1853                                                       oap_pending_item);
1854         ENTRY;
1855
1856         EASSERT((ext->oe_state == OES_CACHE || ext->oe_state == OES_LOCK_DONE),
1857                 ext);
1858
1859         *max_pages = max(ext->oe_mppr, *max_pages);
1860         if (*pc + ext->oe_nr_pages > *max_pages)
1861                 RETURN(0);
1862
1863         list_for_each_entry(tmp, rpclist, oe_link) {
1864                 struct osc_async_page *oap2;
1865                 oap2 = list_first_entry(&tmp->oe_pages, struct osc_async_page,
1866                                         oap_pending_item);
1867                 EASSERT(tmp->oe_owner == current, tmp);
1868 #if 0
1869                 if (overlapped(tmp, ext)) {
1870                         OSC_EXTENT_DUMP(D_ERROR, tmp, "overlapped %p.\n", ext);
1871                         EASSERT(0, ext);
1872                 }
1873 #endif
1874                 if (oap2cl_page(oap)->cp_type != oap2cl_page(oap2)->cp_type) {
1875                         CDEBUG(D_CACHE, "Do not permit different type of IO"
1876                                         " for a same RPC\n");
1877                         RETURN(0);
1878                 }
1879
1880                 if (tmp->oe_srvlock != ext->oe_srvlock ||
1881                     !tmp->oe_grants != !ext->oe_grants)
1882                         RETURN(0);
1883
1884                 /* remove break for strict check */
1885                 break;
1886         }
1887
1888         *pc += ext->oe_nr_pages;
1889         list_move_tail(&ext->oe_link, rpclist);
1890         ext->oe_owner = current;
1891         RETURN(1);
1892 }
1893
1894 /**
1895  * In order to prevent multiple ptlrpcd from breaking contiguous extents,
1896  * get_write_extent() takes all appropriate extents in atomic.
1897  *
1898  * The following policy is used to collect extents for IO:
1899  * 1. Add as many HP extents as possible;
1900  * 2. Add the first urgent extent in urgent extent list and take it out of
1901  *    urgent list;
1902  * 3. Add subsequent extents of this urgent extent;
1903  * 4. If urgent list is not empty, goto 2;
1904  * 5. Traverse the extent tree from the 1st extent;
1905  * 6. Above steps exit if there is no space in this RPC.
1906  */
1907 static int get_write_extents(struct osc_object *obj, struct list_head *rpclist)
1908 {
1909         struct client_obd *cli = osc_cli(obj);
1910         struct osc_extent *ext;
1911         int page_count = 0;
1912         unsigned int max_pages = cli->cl_max_pages_per_rpc;
1913
1914         LASSERT(osc_object_is_locked(obj));
1915         while (!list_empty(&obj->oo_hp_exts)) {
1916                 ext = list_entry(obj->oo_hp_exts.next, struct osc_extent,
1917                                  oe_link);
1918                 LASSERT(ext->oe_state == OES_CACHE);
1919                 if (!try_to_add_extent_for_io(cli, ext, rpclist, &page_count,
1920                                               &max_pages))
1921                         return page_count;
1922                 EASSERT(ext->oe_nr_pages <= max_pages, ext);
1923         }
1924         if (page_count == max_pages)
1925                 return page_count;
1926
1927         while (!list_empty(&obj->oo_urgent_exts)) {
1928                 ext = list_entry(obj->oo_urgent_exts.next,
1929                                  struct osc_extent, oe_link);
1930                 if (!try_to_add_extent_for_io(cli, ext, rpclist, &page_count,
1931                                               &max_pages))
1932                         return page_count;
1933
1934                 if (!ext->oe_intree)
1935                         continue;
1936
1937                 while ((ext = next_extent(ext)) != NULL) {
1938                         if ((ext->oe_state != OES_CACHE) ||
1939                             (!list_empty(&ext->oe_link) &&
1940                              ext->oe_owner != NULL))
1941                                 continue;
1942
1943                         if (!try_to_add_extent_for_io(cli, ext, rpclist,
1944                                                       &page_count, &max_pages))
1945                                 return page_count;
1946                 }
1947         }
1948         if (page_count == max_pages)
1949                 return page_count;
1950
1951         ext = first_extent(obj);
1952         while (ext != NULL) {
1953                 if ((ext->oe_state != OES_CACHE) ||
1954                     /* this extent may be already in current rpclist */
1955                     (!list_empty(&ext->oe_link) && ext->oe_owner != NULL)) {
1956                         ext = next_extent(ext);
1957                         continue;
1958                 }
1959
1960                 if (!try_to_add_extent_for_io(cli, ext, rpclist, &page_count,
1961                                               &max_pages))
1962                         return page_count;
1963
1964                 ext = next_extent(ext);
1965         }
1966         return page_count;
1967 }
1968
1969 static int
1970 osc_send_write_rpc(const struct lu_env *env, struct client_obd *cli,
1971                    struct osc_object *osc, pdl_policy_t pol)
1972 __must_hold(osc)
1973 {
1974         struct list_head   rpclist = LIST_HEAD_INIT(rpclist);
1975         struct osc_extent *ext;
1976         struct osc_extent *tmp;
1977         struct osc_extent *first = NULL;
1978         obd_count page_count = 0;
1979         int srvlock = 0;
1980         int rc = 0;
1981         ENTRY;
1982
1983         LASSERT(osc_object_is_locked(osc));
1984
1985         page_count = get_write_extents(osc, &rpclist);
1986         LASSERT(equi(page_count == 0, list_empty(&rpclist)));
1987
1988         if (list_empty(&rpclist))
1989                 RETURN(0);
1990
1991         osc_update_pending(osc, OBD_BRW_WRITE, -page_count);
1992
1993         list_for_each_entry(ext, &rpclist, oe_link) {
1994                 LASSERT(ext->oe_state == OES_CACHE ||
1995                         ext->oe_state == OES_LOCK_DONE);
1996                 if (ext->oe_state == OES_CACHE)
1997                         osc_extent_state_set(ext, OES_LOCKING);
1998                 else
1999                         osc_extent_state_set(ext, OES_RPC);
2000         }
2001
2002         /* we're going to grab page lock, so release object lock because
2003          * lock order is page lock -> object lock. */
2004         osc_object_unlock(osc);
2005
2006         list_for_each_entry_safe(ext, tmp, &rpclist, oe_link) {
2007                 if (ext->oe_state == OES_LOCKING) {
2008                         rc = osc_extent_make_ready(env, ext);
2009                         if (unlikely(rc < 0)) {
2010                                 list_del_init(&ext->oe_link);
2011                                 osc_extent_finish(env, ext, 0, rc);
2012                                 continue;
2013                         }
2014                 }
2015                 if (first == NULL) {
2016                         first = ext;
2017                         srvlock = ext->oe_srvlock;
2018                 } else {
2019                         LASSERT(srvlock == ext->oe_srvlock);
2020                 }
2021         }
2022
2023         if (!list_empty(&rpclist)) {
2024                 LASSERT(page_count > 0);
2025                 rc = osc_build_rpc(env, cli, &rpclist, OBD_BRW_WRITE, pol);
2026                 LASSERT(list_empty(&rpclist));
2027         }
2028
2029         osc_object_lock(osc);
2030         RETURN(rc);
2031 }
2032
2033 /**
2034  * prepare pages for ASYNC io and put pages in send queue.
2035  *
2036  * \param cmd OBD_BRW_* macroses
2037  * \param lop pending pages
2038  *
2039  * \return zero if no page added to send queue.
2040  * \return 1 if pages successfully added to send queue.
2041  * \return negative on errors.
2042  */
2043 static int
2044 osc_send_read_rpc(const struct lu_env *env, struct client_obd *cli,
2045                   struct osc_object *osc, pdl_policy_t pol)
2046 __must_hold(osc)
2047 {
2048         struct osc_extent *ext;
2049         struct osc_extent *next;
2050         struct list_head rpclist = LIST_HEAD_INIT(rpclist);
2051         int page_count = 0;
2052         unsigned int max_pages = cli->cl_max_pages_per_rpc;
2053         int rc = 0;
2054         ENTRY;
2055
2056         LASSERT(osc_object_is_locked(osc));
2057         list_for_each_entry_safe(ext, next,
2058                                      &osc->oo_reading_exts, oe_link) {
2059                 EASSERT(ext->oe_state == OES_LOCK_DONE, ext);
2060                 if (!try_to_add_extent_for_io(cli, ext, &rpclist, &page_count,
2061                                               &max_pages))
2062                         break;
2063                 osc_extent_state_set(ext, OES_RPC);
2064                 EASSERT(ext->oe_nr_pages <= max_pages, ext);
2065         }
2066         LASSERT(page_count <= max_pages);
2067
2068         osc_update_pending(osc, OBD_BRW_READ, -page_count);
2069
2070         if (!list_empty(&rpclist)) {
2071                 osc_object_unlock(osc);
2072
2073                 LASSERT(page_count > 0);
2074                 rc = osc_build_rpc(env, cli, &rpclist, OBD_BRW_READ, pol);
2075                 LASSERT(list_empty(&rpclist));
2076
2077                 osc_object_lock(osc);
2078         }
2079         RETURN(rc);
2080 }
2081
2082 #define list_to_obj(list, item) ({                                            \
2083         struct list_head *__tmp = (list)->next;                               \
2084         list_del_init(__tmp);                                         \
2085         list_entry(__tmp, struct osc_object, oo_##item);                      \
2086 })
2087
2088 /* This is called by osc_check_rpcs() to find which objects have pages that
2089  * we could be sending.  These lists are maintained by osc_makes_rpc(). */
2090 static struct osc_object *osc_next_obj(struct client_obd *cli)
2091 {
2092         ENTRY;
2093
2094         /* First return objects that have blocked locks so that they
2095          * will be flushed quickly and other clients can get the lock,
2096          * then objects which have pages ready to be stuffed into RPCs */
2097         if (!list_empty(&cli->cl_loi_hp_ready_list))
2098                 RETURN(list_to_obj(&cli->cl_loi_hp_ready_list, hp_ready_item));
2099         if (!list_empty(&cli->cl_loi_ready_list))
2100                 RETURN(list_to_obj(&cli->cl_loi_ready_list, ready_item));
2101
2102         /* then if we have cache waiters, return all objects with queued
2103          * writes.  This is especially important when many small files
2104          * have filled up the cache and not been fired into rpcs because
2105          * they don't pass the nr_pending/object threshhold */
2106         if (!list_empty(&cli->cl_cache_waiters) &&
2107             !list_empty(&cli->cl_loi_write_list))
2108                 RETURN(list_to_obj(&cli->cl_loi_write_list, write_item));
2109
2110         /* then return all queued objects when we have an invalid import
2111          * so that they get flushed */
2112         if (cli->cl_import == NULL || cli->cl_import->imp_invalid) {
2113                 if (!list_empty(&cli->cl_loi_write_list))
2114                         RETURN(list_to_obj(&cli->cl_loi_write_list,
2115                                            write_item));
2116                 if (!list_empty(&cli->cl_loi_read_list))
2117                         RETURN(list_to_obj(&cli->cl_loi_read_list,
2118                                            read_item));
2119         }
2120         RETURN(NULL);
2121 }
2122
2123 /* called with the loi list lock held */
2124 static void osc_check_rpcs(const struct lu_env *env, struct client_obd *cli,
2125                            pdl_policy_t pol)
2126 __must_hold(&cli->cl_loi_list_lock)
2127 {
2128         struct osc_object *osc;
2129         int rc = 0;
2130         ENTRY;
2131
2132         while ((osc = osc_next_obj(cli)) != NULL) {
2133                 struct cl_object *obj = osc2cl(osc);
2134                 struct lu_ref_link link;
2135
2136                 OSC_IO_DEBUG(osc, "%lu in flight\n", rpcs_in_flight(cli));
2137
2138                 if (osc_max_rpc_in_flight(cli, osc)) {
2139                         __osc_list_maint(cli, osc);
2140                         break;
2141                 }
2142
2143                 cl_object_get(obj);
2144                 client_obd_list_unlock(&cli->cl_loi_list_lock);
2145                 lu_object_ref_add_at(&obj->co_lu, &link, "check", current);
2146
2147                 /* attempt some read/write balancing by alternating between
2148                  * reads and writes in an object.  The makes_rpc checks here
2149                  * would be redundant if we were getting read/write work items
2150                  * instead of objects.  we don't want send_oap_rpc to drain a
2151                  * partial read pending queue when we're given this object to
2152                  * do io on writes while there are cache waiters */
2153                 osc_object_lock(osc);
2154                 if (osc_makes_rpc(cli, osc, OBD_BRW_WRITE)) {
2155                         rc = osc_send_write_rpc(env, cli, osc, pol);
2156                         if (rc < 0) {
2157                                 CERROR("Write request failed with %d\n", rc);
2158
2159                                 /* osc_send_write_rpc failed, mostly because of
2160                                  * memory pressure.
2161                                  *
2162                                  * It can't break here, because if:
2163                                  *  - a page was submitted by osc_io_submit, so
2164                                  *    page locked;
2165                                  *  - no request in flight
2166                                  *  - no subsequent request
2167                                  * The system will be in live-lock state,
2168                                  * because there is no chance to call
2169                                  * osc_io_unplug() and osc_check_rpcs() any
2170                                  * more. pdflush can't help in this case,
2171                                  * because it might be blocked at grabbing
2172                                  * the page lock as we mentioned.
2173                                  *
2174                                  * Anyway, continue to drain pages. */
2175                                 /* break; */
2176                         }
2177                 }
2178                 if (osc_makes_rpc(cli, osc, OBD_BRW_READ)) {
2179                         rc = osc_send_read_rpc(env, cli, osc, pol);
2180                         if (rc < 0)
2181                                 CERROR("Read request failed with %d\n", rc);
2182                 }
2183                 osc_object_unlock(osc);
2184
2185                 osc_list_maint(cli, osc);
2186                 lu_object_ref_del_at(&obj->co_lu, &link, "check", current);
2187                 cl_object_put(env, obj);
2188
2189                 client_obd_list_lock(&cli->cl_loi_list_lock);
2190         }
2191 }
2192
2193 static int osc_io_unplug0(const struct lu_env *env, struct client_obd *cli,
2194                           struct osc_object *osc, pdl_policy_t pol, int async)
2195 {
2196         int rc = 0;
2197
2198         if (osc != NULL && osc_list_maint(cli, osc) == 0)
2199                 return 0;
2200
2201         if (!async) {
2202                 /* disable osc_lru_shrink() temporarily to avoid
2203                  * potential stack overrun problem. LU-2859 */
2204                 atomic_inc(&cli->cl_lru_shrinkers);
2205                 client_obd_list_lock(&cli->cl_loi_list_lock);
2206                 osc_check_rpcs(env, cli, pol);
2207                 client_obd_list_unlock(&cli->cl_loi_list_lock);
2208                 atomic_dec(&cli->cl_lru_shrinkers);
2209         } else {
2210                 CDEBUG(D_CACHE, "Queue writeback work for client %p.\n", cli);
2211                 LASSERT(cli->cl_writeback_work != NULL);
2212                 rc = ptlrpcd_queue_work(cli->cl_writeback_work);
2213         }
2214         return rc;
2215 }
2216
2217 static int osc_io_unplug_async(const struct lu_env *env,
2218                                 struct client_obd *cli, struct osc_object *osc)
2219 {
2220         /* XXX: policy is no use actually. */
2221         return osc_io_unplug0(env, cli, osc, PDL_POLICY_ROUND, 1);
2222 }
2223
2224 void osc_io_unplug(const struct lu_env *env, struct client_obd *cli,
2225                    struct osc_object *osc, pdl_policy_t pol)
2226 {
2227         (void)osc_io_unplug0(env, cli, osc, pol, 0);
2228 }
2229
2230 int osc_prep_async_page(struct osc_object *osc, struct osc_page *ops,
2231                         struct page *page, loff_t offset)
2232 {
2233         struct obd_export     *exp = osc_export(osc);
2234         struct osc_async_page *oap = &ops->ops_oap;
2235         ENTRY;
2236
2237         if (!page)
2238                 return cfs_size_round(sizeof(*oap));
2239
2240         oap->oap_magic = OAP_MAGIC;
2241         oap->oap_cli = &exp->exp_obd->u.cli;
2242         oap->oap_obj = osc;
2243
2244         oap->oap_page = page;
2245         oap->oap_obj_off = offset;
2246         LASSERT(!(offset & ~CFS_PAGE_MASK));
2247
2248         if (!client_is_remote(exp) && cfs_capable(CFS_CAP_SYS_RESOURCE))
2249                 oap->oap_brw_flags = OBD_BRW_NOQUOTA;
2250
2251         INIT_LIST_HEAD(&oap->oap_pending_item);
2252         INIT_LIST_HEAD(&oap->oap_rpc_item);
2253
2254         spin_lock_init(&oap->oap_lock);
2255         CDEBUG(D_INFO, "oap %p page %p obj off "LPU64"\n",
2256                oap, page, oap->oap_obj_off);
2257         RETURN(0);
2258 }
2259
2260 int osc_queue_async_io(const struct lu_env *env, struct cl_io *io,
2261                        struct osc_page *ops)
2262 {
2263         struct osc_io *oio = osc_env_io(env);
2264         struct osc_extent     *ext = NULL;
2265         struct osc_async_page *oap = &ops->ops_oap;
2266         struct client_obd     *cli = oap->oap_cli;
2267         struct osc_object     *osc = oap->oap_obj;
2268         pgoff_t index;
2269         int    grants = 0;
2270         int    brw_flags = OBD_BRW_ASYNC;
2271         int    cmd = OBD_BRW_WRITE;
2272         int    need_release = 0;
2273         int    rc = 0;
2274         ENTRY;
2275
2276         if (oap->oap_magic != OAP_MAGIC)
2277                 RETURN(-EINVAL);
2278
2279         if (cli->cl_import == NULL || cli->cl_import->imp_invalid)
2280                 RETURN(-EIO);
2281
2282         if (!list_empty(&oap->oap_pending_item) ||
2283             !list_empty(&oap->oap_rpc_item))
2284                 RETURN(-EBUSY);
2285
2286         /* Set the OBD_BRW_SRVLOCK before the page is queued. */
2287         brw_flags |= ops->ops_srvlock ? OBD_BRW_SRVLOCK : 0;
2288         if (!client_is_remote(osc_export(osc)) &&
2289             cfs_capable(CFS_CAP_SYS_RESOURCE)) {
2290                 brw_flags |= OBD_BRW_NOQUOTA;
2291                 cmd |= OBD_BRW_NOQUOTA;
2292         }
2293
2294         /* check if the file's owner/group is over quota */
2295         if (!(cmd & OBD_BRW_NOQUOTA)) {
2296                 struct cl_object *obj;
2297                 struct cl_attr   *attr;
2298                 unsigned int qid[MAXQUOTAS];
2299
2300                 obj = cl_object_top(&osc->oo_cl);
2301                 attr = &osc_env_info(env)->oti_attr;
2302
2303                 cl_object_attr_lock(obj);
2304                 rc = cl_object_attr_get(env, obj, attr);
2305                 cl_object_attr_unlock(obj);
2306
2307                 qid[USRQUOTA] = attr->cat_uid;
2308                 qid[GRPQUOTA] = attr->cat_gid;
2309                 if (rc == 0 && osc_quota_chkdq(cli, qid) == NO_QUOTA)
2310                         rc = -EDQUOT;
2311                 if (rc)
2312                         RETURN(rc);
2313         }
2314
2315         oap->oap_cmd = cmd;
2316         oap->oap_page_off = ops->ops_from;
2317         oap->oap_count = ops->ops_to - ops->ops_from;
2318         /* No need to hold a lock here,
2319          * since this page is not in any list yet. */
2320         oap->oap_async_flags = 0;
2321         oap->oap_brw_flags = brw_flags;
2322
2323         OSC_IO_DEBUG(osc, "oap %p page %p added for cmd %d\n",
2324                      oap, oap->oap_page, oap->oap_cmd & OBD_BRW_RWMASK);
2325
2326         index = osc_index(oap2osc(oap));
2327
2328         /* Add this page into extent by the following steps:
2329          * 1. if there exists an active extent for this IO, mostly this page
2330          *    can be added to the active extent and sometimes we need to
2331          *    expand extent to accomodate this page;
2332          * 2. otherwise, a new extent will be allocated. */
2333
2334         ext = oio->oi_active;
2335         if (ext != NULL && ext->oe_start <= index && ext->oe_max_end >= index) {
2336                 /* one chunk plus extent overhead must be enough to write this
2337                  * page */
2338                 grants = (1 << cli->cl_chunkbits) + cli->cl_extent_tax;
2339                 if (ext->oe_end >= index)
2340                         grants = 0;
2341
2342                 /* it doesn't need any grant to dirty this page */
2343                 client_obd_list_lock(&cli->cl_loi_list_lock);
2344                 rc = osc_enter_cache_try(cli, oap, grants, 0);
2345                 client_obd_list_unlock(&cli->cl_loi_list_lock);
2346                 if (rc == 0) { /* try failed */
2347                         grants = 0;
2348                         need_release = 1;
2349                 } else if (ext->oe_end < index) {
2350                         int tmp = grants;
2351                         /* try to expand this extent */
2352                         rc = osc_extent_expand(ext, index, &tmp);
2353                         if (rc < 0) {
2354                                 need_release = 1;
2355                                 /* don't free reserved grant */
2356                         } else {
2357                                 OSC_EXTENT_DUMP(D_CACHE, ext,
2358                                                 "expanded for %lu.\n", index);
2359                                 osc_unreserve_grant(cli, grants, tmp);
2360                                 grants = 0;
2361                         }
2362                 }
2363                 rc = 0;
2364         } else if (ext != NULL) {
2365                 /* index is located outside of active extent */
2366                 need_release = 1;
2367         }
2368         if (need_release) {
2369                 osc_extent_release(env, ext);
2370                 oio->oi_active = NULL;
2371                 ext = NULL;
2372         }
2373
2374         if (ext == NULL) {
2375                 int tmp = (1 << cli->cl_chunkbits) + cli->cl_extent_tax;
2376
2377                 /* try to find new extent to cover this page */
2378                 LASSERT(oio->oi_active == NULL);
2379                 /* we may have allocated grant for this page if we failed
2380                  * to expand the previous active extent. */
2381                 LASSERT(ergo(grants > 0, grants >= tmp));
2382
2383                 rc = 0;
2384                 if (grants == 0) {
2385                         /* we haven't allocated grant for this page. */
2386                         rc = osc_enter_cache(env, cli, oap, tmp);
2387                         if (rc == 0)
2388                                 grants = tmp;
2389                 }
2390
2391                 tmp = grants;
2392                 if (rc == 0) {
2393                         ext = osc_extent_find(env, osc, index, &tmp);
2394                         if (IS_ERR(ext)) {
2395                                 LASSERT(tmp == grants);
2396                                 osc_exit_cache(cli, oap);
2397                                 rc = PTR_ERR(ext);
2398                                 ext = NULL;
2399                         } else {
2400                                 oio->oi_active = ext;
2401                         }
2402                 }
2403                 if (grants > 0)
2404                         osc_unreserve_grant(cli, grants, tmp);
2405         }
2406
2407         LASSERT(ergo(rc == 0, ext != NULL));
2408         if (ext != NULL) {
2409                 EASSERTF(ext->oe_end >= index && ext->oe_start <= index,
2410                          ext, "index = %lu.\n", index);
2411                 LASSERT((oap->oap_brw_flags & OBD_BRW_FROM_GRANT) != 0);
2412
2413                 osc_object_lock(osc);
2414                 if (ext->oe_nr_pages == 0)
2415                         ext->oe_srvlock = ops->ops_srvlock;
2416                 else
2417                         LASSERT(ext->oe_srvlock == ops->ops_srvlock);
2418                 ++ext->oe_nr_pages;
2419                 list_add_tail(&oap->oap_pending_item, &ext->oe_pages);
2420                 osc_object_unlock(osc);
2421         }
2422         RETURN(rc);
2423 }
2424
2425 int osc_teardown_async_page(const struct lu_env *env,
2426                             struct osc_object *obj, struct osc_page *ops)
2427 {
2428         struct osc_async_page *oap = &ops->ops_oap;
2429         struct osc_extent     *ext = NULL;
2430         int rc = 0;
2431         ENTRY;
2432
2433         LASSERT(oap->oap_magic == OAP_MAGIC);
2434
2435         CDEBUG(D_INFO, "teardown oap %p page %p at index %lu.\n",
2436                oap, ops, osc_index(oap2osc(oap)));
2437
2438         osc_object_lock(obj);
2439         if (!list_empty(&oap->oap_rpc_item)) {
2440                 CDEBUG(D_CACHE, "oap %p is not in cache.\n", oap);
2441                 rc = -EBUSY;
2442         } else if (!list_empty(&oap->oap_pending_item)) {
2443                 ext = osc_extent_lookup(obj, osc_index(oap2osc(oap)));
2444                 /* only truncated pages are allowed to be taken out.
2445                  * See osc_extent_truncate() and osc_cache_truncate_start()
2446                  * for details. */
2447                 if (ext != NULL && ext->oe_state != OES_TRUNC) {
2448                         OSC_EXTENT_DUMP(D_ERROR, ext, "trunc at %lu.\n",
2449                                         osc_index(oap2osc(oap)));
2450                         rc = -EBUSY;
2451                 }
2452         }
2453         osc_object_unlock(obj);
2454         if (ext != NULL)
2455                 osc_extent_put(env, ext);
2456         RETURN(rc);
2457 }
2458
2459 /**
2460  * This is called when a page is picked up by kernel to write out.
2461  *
2462  * We should find out the corresponding extent and add the whole extent
2463  * into urgent list. The extent may be being truncated or used, handle it
2464  * carefully.
2465  */
2466 int osc_flush_async_page(const struct lu_env *env, struct cl_io *io,
2467                          struct osc_page *ops)
2468 {
2469         struct osc_extent *ext   = NULL;
2470         struct osc_object *obj   = cl2osc(ops->ops_cl.cpl_obj);
2471         struct cl_page    *cp    = ops->ops_cl.cpl_page;
2472         pgoff_t            index = osc_index(ops);
2473         struct osc_async_page *oap = &ops->ops_oap;
2474         bool unplug = false;
2475         int rc = 0;
2476         ENTRY;
2477
2478         osc_object_lock(obj);
2479         ext = osc_extent_lookup(obj, index);
2480         if (ext == NULL) {
2481                 osc_extent_tree_dump(D_ERROR, obj);
2482                 LASSERTF(0, "page index %lu is NOT covered.\n", index);
2483         }
2484
2485         switch (ext->oe_state) {
2486         case OES_RPC:
2487         case OES_LOCK_DONE:
2488                 CL_PAGE_DEBUG(D_ERROR, env, cp, "flush an in-rpc page?\n");
2489                 LASSERT(0);
2490                 break;
2491         case OES_LOCKING:
2492                 /* If we know this extent is being written out, we should abort
2493                  * so that the writer can make this page ready. Otherwise, there
2494                  * exists a deadlock problem because other process can wait for
2495                  * page writeback bit holding page lock; and meanwhile in
2496                  * vvp_page_make_ready(), we need to grab page lock before
2497                  * really sending the RPC. */
2498         case OES_TRUNC:
2499                 /* race with truncate, page will be redirtied */
2500         case OES_ACTIVE:
2501                 /* The extent is active so we need to abort and let the caller
2502                  * re-dirty the page. If we continued on here, and we were the
2503                  * one making the extent active, we could deadlock waiting for
2504                  * the page writeback to clear but it won't because the extent
2505                  * is active and won't be written out. */
2506                 GOTO(out, rc = -EAGAIN);
2507         default:
2508                 break;
2509         }
2510
2511         rc = cl_page_prep(env, io, cp, CRT_WRITE);
2512         if (rc)
2513                 GOTO(out, rc);
2514
2515         spin_lock(&oap->oap_lock);
2516         oap->oap_async_flags |= ASYNC_READY|ASYNC_URGENT;
2517         spin_unlock(&oap->oap_lock);
2518
2519         if (memory_pressure_get())
2520                 ext->oe_memalloc = 1;
2521
2522         ext->oe_urgent = 1;
2523         if (ext->oe_state == OES_CACHE) {
2524                 OSC_EXTENT_DUMP(D_CACHE, ext,
2525                                 "flush page %p make it urgent.\n", oap);
2526                 if (list_empty(&ext->oe_link))
2527                         list_add_tail(&ext->oe_link, &obj->oo_urgent_exts);
2528                 unplug = true;
2529         }
2530         rc = 0;
2531         EXIT;
2532
2533 out:
2534         osc_object_unlock(obj);
2535         osc_extent_put(env, ext);
2536         if (unplug)
2537                 osc_io_unplug_async(env, osc_cli(obj), obj);
2538         return rc;
2539 }
2540
2541 /**
2542  * this is called when a sync waiter receives an interruption.  Its job is to
2543  * get the caller woken as soon as possible.  If its page hasn't been put in an
2544  * rpc yet it can dequeue immediately.  Otherwise it has to mark the rpc as
2545  * desiring interruption which will forcefully complete the rpc once the rpc
2546  * has timed out.
2547  */
2548 int osc_cancel_async_page(const struct lu_env *env, struct osc_page *ops)
2549 {
2550         struct osc_async_page *oap = &ops->ops_oap;
2551         struct osc_object     *obj = oap->oap_obj;
2552         struct client_obd     *cli = osc_cli(obj);
2553         struct osc_extent     *ext;
2554         struct osc_extent     *found = NULL;
2555         struct list_head            *plist;
2556         pgoff_t index = osc_index(ops);
2557         int     rc = -EBUSY;
2558         int     cmd;
2559         ENTRY;
2560
2561         LASSERT(!oap->oap_interrupted);
2562         oap->oap_interrupted = 1;
2563
2564         /* Find out the caching extent */
2565         osc_object_lock(obj);
2566         if (oap->oap_cmd & OBD_BRW_WRITE) {
2567                 plist = &obj->oo_urgent_exts;
2568                 cmd   = OBD_BRW_WRITE;
2569         } else {
2570                 plist = &obj->oo_reading_exts;
2571                 cmd   = OBD_BRW_READ;
2572         }
2573         list_for_each_entry(ext, plist, oe_link) {
2574                 if (ext->oe_start <= index && ext->oe_end >= index) {
2575                         LASSERT(ext->oe_state == OES_LOCK_DONE);
2576                         /* For OES_LOCK_DONE state extent, it has already held
2577                          * a refcount for RPC. */
2578                         found = osc_extent_get(ext);
2579                         break;
2580                 }
2581         }
2582         if (found != NULL) {
2583                 list_del_init(&found->oe_link);
2584                 osc_update_pending(obj, cmd, -found->oe_nr_pages);
2585                 osc_object_unlock(obj);
2586
2587                 osc_extent_finish(env, found, 0, -EINTR);
2588                 osc_extent_put(env, found);
2589                 rc = 0;
2590         } else {
2591                 osc_object_unlock(obj);
2592                 /* ok, it's been put in an rpc. only one oap gets a request
2593                  * reference */
2594                 if (oap->oap_request != NULL) {
2595                         ptlrpc_mark_interrupted(oap->oap_request);
2596                         ptlrpcd_wake(oap->oap_request);
2597                         ptlrpc_req_finished(oap->oap_request);
2598                         oap->oap_request = NULL;
2599                 }
2600         }
2601
2602         osc_list_maint(cli, obj);
2603         RETURN(rc);
2604 }
2605
2606 int osc_queue_sync_pages(const struct lu_env *env, struct osc_object *obj,
2607                          struct list_head *list, int cmd, int brw_flags)
2608 {
2609         struct client_obd     *cli = osc_cli(obj);
2610         struct osc_extent     *ext;
2611         struct osc_async_page *oap;
2612         int     page_count = 0;
2613         int     mppr       = cli->cl_max_pages_per_rpc;
2614         pgoff_t start      = CL_PAGE_EOF;
2615         pgoff_t end        = 0;
2616         ENTRY;
2617
2618         list_for_each_entry(oap, list, oap_pending_item) {
2619                 pgoff_t index = osc_index(oap2osc(oap));
2620                 if (index > end)
2621                         end = index;
2622                 if (index < start)
2623                         start = index;
2624                 ++page_count;
2625                 mppr <<= (page_count > mppr);
2626         }
2627
2628         ext = osc_extent_alloc(obj);
2629         if (ext == NULL) {
2630                 list_for_each_entry(oap, list, oap_pending_item) {
2631                         list_del_init(&oap->oap_pending_item);
2632                         osc_ap_completion(env, cli, oap, 0, -ENOMEM);
2633                 }
2634                 RETURN(-ENOMEM);
2635         }
2636
2637         ext->oe_rw = !!(cmd & OBD_BRW_READ);
2638         ext->oe_sync = 1;
2639         ext->oe_urgent = 1;
2640         ext->oe_start = start;
2641         ext->oe_end = ext->oe_max_end = end;
2642         ext->oe_obj = obj;
2643         ext->oe_srvlock = !!(brw_flags & OBD_BRW_SRVLOCK);
2644         ext->oe_nr_pages = page_count;
2645         ext->oe_mppr = mppr;
2646         list_splice_init(list, &ext->oe_pages);
2647
2648         osc_object_lock(obj);
2649         /* Reuse the initial refcount for RPC, don't drop it */
2650         osc_extent_state_set(ext, OES_LOCK_DONE);
2651         if (cmd & OBD_BRW_WRITE) {
2652                 list_add_tail(&ext->oe_link, &obj->oo_urgent_exts);
2653                 osc_update_pending(obj, OBD_BRW_WRITE, page_count);
2654         } else {
2655                 list_add_tail(&ext->oe_link, &obj->oo_reading_exts);
2656                 osc_update_pending(obj, OBD_BRW_READ, page_count);
2657         }
2658         osc_object_unlock(obj);
2659
2660         osc_io_unplug_async(env, cli, obj);
2661         RETURN(0);
2662 }
2663
2664 /**
2665  * Called by osc_io_setattr_start() to freeze and destroy covering extents.
2666  */
2667 int osc_cache_truncate_start(const struct lu_env *env, struct osc_io *oio,
2668                              struct osc_object *obj, __u64 size)
2669 {
2670         struct client_obd *cli = osc_cli(obj);
2671         struct osc_extent *ext;
2672         struct osc_extent *waiting = NULL;
2673         pgoff_t index;
2674         struct list_head list = LIST_HEAD_INIT(list);
2675         int result = 0;
2676         bool partial;
2677         ENTRY;
2678
2679         /* pages with index greater or equal to index will be truncated. */
2680         index = cl_index(osc2cl(obj), size);
2681         partial = size > cl_offset(osc2cl(obj), index);
2682
2683 again:
2684         osc_object_lock(obj);
2685         ext = osc_extent_search(obj, index);
2686         if (ext == NULL)
2687                 ext = first_extent(obj);
2688         else if (ext->oe_end < index)
2689                 ext = next_extent(ext);
2690         while (ext != NULL) {
2691                 EASSERT(ext->oe_state != OES_TRUNC, ext);
2692
2693                 if (ext->oe_state > OES_CACHE || ext->oe_urgent) {
2694                         /* if ext is in urgent state, it means there must exist
2695                          * a page already having been flushed by write_page().
2696                          * We have to wait for this extent because we can't
2697                          * truncate that page. */
2698                         LASSERT(!ext->oe_hp);
2699                         OSC_EXTENT_DUMP(D_CACHE, ext,
2700                                         "waiting for busy extent\n");
2701                         waiting = osc_extent_get(ext);
2702                         break;
2703                 }
2704
2705                 OSC_EXTENT_DUMP(D_CACHE, ext, "try to trunc:"LPU64".\n", size);
2706
2707                 osc_extent_get(ext);
2708                 if (ext->oe_state == OES_ACTIVE) {
2709                         /* though we grab inode mutex for write path, but we
2710                          * release it before releasing extent(in osc_io_end()),
2711                          * so there is a race window that an extent is still
2712                          * in OES_ACTIVE when truncate starts. */
2713                         LASSERT(!ext->oe_trunc_pending);
2714                         ext->oe_trunc_pending = 1;
2715                 } else {
2716                         EASSERT(ext->oe_state == OES_CACHE, ext);
2717                         osc_extent_state_set(ext, OES_TRUNC);
2718                         osc_update_pending(obj, OBD_BRW_WRITE,
2719                                            -ext->oe_nr_pages);
2720                 }
2721                 EASSERT(list_empty(&ext->oe_link), ext);
2722                 list_add_tail(&ext->oe_link, &list);
2723
2724                 ext = next_extent(ext);
2725         }
2726         osc_object_unlock(obj);
2727
2728         osc_list_maint(cli, obj);
2729
2730         while (!list_empty(&list)) {
2731                 int rc;
2732
2733                 ext = list_entry(list.next, struct osc_extent, oe_link);
2734                 list_del_init(&ext->oe_link);
2735
2736                 /* extent may be in OES_ACTIVE state because inode mutex
2737                  * is released before osc_io_end() in file write case */
2738                 if (ext->oe_state != OES_TRUNC)
2739                         osc_extent_wait(env, ext, OES_TRUNC);
2740
2741                 rc = osc_extent_truncate(ext, index, partial);
2742                 if (rc < 0) {
2743                         if (result == 0)
2744                                 result = rc;
2745
2746                         OSC_EXTENT_DUMP(D_ERROR, ext,
2747                                         "truncate error %d\n", rc);
2748                 } else if (ext->oe_nr_pages == 0) {
2749                         osc_extent_remove(ext);
2750                 } else {
2751                         /* this must be an overlapped extent which means only
2752                          * part of pages in this extent have been truncated.
2753                          */
2754                         EASSERTF(ext->oe_start <= index, ext,
2755                                  "trunc index = %lu/%d.\n", index, partial);
2756                         /* fix index to skip this partially truncated extent */
2757                         index = ext->oe_end + 1;
2758                         partial = false;
2759
2760                         /* we need to hold this extent in OES_TRUNC state so
2761                          * that no writeback will happen. This is to avoid
2762                          * BUG 17397. */
2763                         LASSERT(oio->oi_trunc == NULL);
2764                         oio->oi_trunc = osc_extent_get(ext);
2765                         OSC_EXTENT_DUMP(D_CACHE, ext,
2766                                         "trunc at "LPU64"\n", size);
2767                 }
2768                 osc_extent_put(env, ext);
2769         }
2770         if (waiting != NULL) {
2771                 int rc;
2772
2773                 /* ignore the result of osc_extent_wait the write initiator
2774                  * should take care of it. */
2775                 rc = osc_extent_wait(env, waiting, OES_INV);
2776                 if (rc < 0)
2777                         OSC_EXTENT_DUMP(D_CACHE, waiting, "error: %d.\n", rc);
2778
2779                 osc_extent_put(env, waiting);
2780                 waiting = NULL;
2781                 goto again;
2782         }
2783         RETURN(result);
2784 }
2785
2786 /**
2787  * Called after osc_io_setattr_end to add oio->oi_trunc back to cache.
2788  */
2789 void osc_cache_truncate_end(const struct lu_env *env, struct osc_io *oio,
2790                             struct osc_object *obj)
2791 {
2792         struct osc_extent *ext = oio->oi_trunc;
2793
2794         oio->oi_trunc = NULL;
2795         if (ext != NULL) {
2796                 bool unplug = false;
2797
2798                 EASSERT(ext->oe_nr_pages > 0, ext);
2799                 EASSERT(ext->oe_state == OES_TRUNC, ext);
2800                 EASSERT(!ext->oe_urgent, ext);
2801
2802                 OSC_EXTENT_DUMP(D_CACHE, ext, "trunc -> cache.\n");
2803                 osc_object_lock(obj);
2804                 osc_extent_state_set(ext, OES_CACHE);
2805                 if (ext->oe_fsync_wait && !ext->oe_urgent) {
2806                         ext->oe_urgent = 1;
2807                         list_move_tail(&ext->oe_link, &obj->oo_urgent_exts);
2808                         unplug = true;
2809                 }
2810                 osc_update_pending(obj, OBD_BRW_WRITE, ext->oe_nr_pages);
2811                 osc_object_unlock(obj);
2812                 osc_extent_put(env, ext);
2813
2814                 if (unplug)
2815                         osc_io_unplug_async(env, osc_cli(obj), obj);
2816         }
2817 }
2818
2819 /**
2820  * Wait for extents in a specific range to be written out.
2821  * The caller must have called osc_cache_writeback_range() to issue IO
2822  * otherwise it will take a long time for this function to finish.
2823  *
2824  * Caller must hold inode_mutex , or cancel exclusive dlm lock so that
2825  * nobody else can dirty this range of file while we're waiting for
2826  * extents to be written.
2827  */
2828 int osc_cache_wait_range(const struct lu_env *env, struct osc_object *obj,
2829                          pgoff_t start, pgoff_t end)
2830 {
2831         struct osc_extent *ext;
2832         pgoff_t index = start;
2833         int     result = 0;
2834         ENTRY;
2835
2836 again:
2837         osc_object_lock(obj);
2838         ext = osc_extent_search(obj, index);
2839         if (ext == NULL)
2840                 ext = first_extent(obj);
2841         else if (ext->oe_end < index)
2842                 ext = next_extent(ext);
2843         while (ext != NULL) {
2844                 int rc;
2845
2846                 if (ext->oe_start > end)
2847                         break;
2848
2849                 if (!ext->oe_fsync_wait) {
2850                         ext = next_extent(ext);
2851                         continue;
2852                 }
2853
2854                 EASSERT(ergo(ext->oe_state == OES_CACHE,
2855                              ext->oe_hp || ext->oe_urgent), ext);
2856                 EASSERT(ergo(ext->oe_state == OES_ACTIVE,
2857                              !ext->oe_hp && ext->oe_urgent), ext);
2858
2859                 index = ext->oe_end + 1;
2860                 osc_extent_get(ext);
2861                 osc_object_unlock(obj);
2862
2863                 rc = osc_extent_wait(env, ext, OES_INV);
2864                 if (result == 0)
2865                         result = rc;
2866                 osc_extent_put(env, ext);
2867                 goto again;
2868         }
2869         osc_object_unlock(obj);
2870
2871         OSC_IO_DEBUG(obj, "sync file range.\n");
2872         RETURN(result);
2873 }
2874
2875 /**
2876  * Called to write out a range of osc object.
2877  *
2878  * @hp     : should be set this is caused by lock cancel;
2879  * @discard: is set if dirty pages should be dropped - file will be deleted or
2880  *         truncated, this implies there is no partially discarding extents.
2881  *
2882  * Return how many pages will be issued, or error code if error occurred.
2883  */
2884 int osc_cache_writeback_range(const struct lu_env *env, struct osc_object *obj,
2885                               pgoff_t start, pgoff_t end, int hp, int discard)
2886 {
2887         struct osc_extent *ext;
2888         struct list_head discard_list = LIST_HEAD_INIT(discard_list);
2889         bool unplug = false;
2890         int result = 0;
2891         ENTRY;
2892
2893         osc_object_lock(obj);
2894         ext = osc_extent_search(obj, start);
2895         if (ext == NULL)
2896                 ext = first_extent(obj);
2897         else if (ext->oe_end < start)
2898                 ext = next_extent(ext);
2899         while (ext != NULL) {
2900                 if (ext->oe_start > end)
2901                         break;
2902
2903                 ext->oe_fsync_wait = 1;
2904                 switch (ext->oe_state) {
2905                 case OES_CACHE:
2906                         result += ext->oe_nr_pages;
2907                         if (!discard) {
2908                                 struct list_head *list = NULL;
2909                                 if (hp) {
2910                                         EASSERT(!ext->oe_hp, ext);
2911                                         ext->oe_hp = 1;
2912                                         list = &obj->oo_hp_exts;
2913                                 } else if (!ext->oe_urgent) {
2914                                         ext->oe_urgent = 1;
2915                                         list = &obj->oo_urgent_exts;
2916                                 }
2917                                 if (list != NULL)
2918                                         list_move_tail(&ext->oe_link, list);
2919                                 unplug = true;
2920                         } else {
2921                                 /* the only discarder is lock cancelling, so
2922                                  * [start, end] must contain this extent */
2923                                 EASSERT(ext->oe_start >= start &&
2924                                         ext->oe_max_end <= end, ext);
2925                                 osc_extent_state_set(ext, OES_LOCKING);
2926                                 ext->oe_owner = current;
2927                                 list_move_tail(&ext->oe_link,
2928                                                    &discard_list);
2929                                 osc_update_pending(obj, OBD_BRW_WRITE,
2930                                                    -ext->oe_nr_pages);
2931                         }
2932                         break;
2933                 case OES_ACTIVE:
2934                         /* It's pretty bad to wait for ACTIVE extents, because
2935                          * we don't know how long we will wait for it to be
2936                          * flushed since it may be blocked at awaiting more
2937                          * grants. We do this for the correctness of fsync. */
2938                         LASSERT(hp == 0 && discard == 0);
2939                         ext->oe_urgent = 1;
2940                         break;
2941                 case OES_TRUNC:
2942                         /* this extent is being truncated, can't do anything
2943                          * for it now. it will be set to urgent after truncate
2944                          * is finished in osc_cache_truncate_end(). */
2945                 default:
2946                         break;
2947                 }
2948                 ext = next_extent(ext);
2949         }
2950         osc_object_unlock(obj);
2951
2952         LASSERT(ergo(!discard, list_empty(&discard_list)));
2953         if (!list_empty(&discard_list)) {
2954                 struct osc_extent *tmp;
2955                 int rc;
2956
2957                 osc_list_maint(osc_cli(obj), obj);
2958                 list_for_each_entry_safe(ext, tmp, &discard_list, oe_link) {
2959                         list_del_init(&ext->oe_link);
2960                         EASSERT(ext->oe_state == OES_LOCKING, ext);
2961
2962                         /* Discard caching pages. We don't actually write this
2963                          * extent out but we complete it as if we did. */
2964                         rc = osc_extent_make_ready(env, ext);
2965                         if (unlikely(rc < 0)) {
2966                                 OSC_EXTENT_DUMP(D_ERROR, ext,
2967                                                 "make_ready returned %d\n", rc);
2968                                 if (result >= 0)
2969                                         result = rc;
2970                         }
2971
2972                         /* finish the extent as if the pages were sent */
2973                         osc_extent_finish(env, ext, 0, 0);
2974                 }
2975         }
2976
2977         if (unplug)
2978                 osc_io_unplug(env, osc_cli(obj), obj, PDL_POLICY_ROUND);
2979
2980         if (hp || discard) {
2981                 int rc;
2982                 rc = osc_cache_wait_range(env, obj, start, end);
2983                 if (result >= 0 && rc < 0)
2984                         result = rc;
2985         }
2986
2987         OSC_IO_DEBUG(obj, "pageout [%lu, %lu], %d.\n", start, end, result);
2988         RETURN(result);
2989 }
2990
2991 /**
2992  * Returns a list of pages by a given [start, end] of \a obj.
2993  *
2994  * \param resched If not NULL, then we give up before hogging CPU for too
2995  * long and set *resched = 1, in that case caller should implement a retry
2996  * logic.
2997  *
2998  * Gang tree lookup (radix_tree_gang_lookup()) optimization is absolutely
2999  * crucial in the face of [offset, EOF] locks.
3000  *
3001  * Return at least one page in @queue unless there is no covered page.
3002  */
3003 int osc_page_gang_lookup(const struct lu_env *env, struct cl_io *io,
3004                         struct osc_object *osc, pgoff_t start, pgoff_t end,
3005                         osc_page_gang_cbt cb, void *cbdata)
3006 {
3007         struct osc_page *ops;
3008         void            **pvec;
3009         pgoff_t         idx;
3010         unsigned int    nr;
3011         unsigned int    i;
3012         unsigned int    j;
3013         int             res = CLP_GANG_OKAY;
3014         bool            tree_lock = true;
3015         ENTRY;
3016
3017         idx = start;
3018         pvec = osc_env_info(env)->oti_pvec;
3019         spin_lock(&osc->oo_tree_lock);
3020         while ((nr = radix_tree_gang_lookup(&osc->oo_tree, pvec,
3021                                             idx, OTI_PVEC_SIZE)) > 0) {
3022                 struct cl_page *page;
3023                 bool end_of_region = false;
3024
3025                 for (i = 0, j = 0; i < nr; ++i) {
3026                         ops = pvec[i];
3027                         pvec[i] = NULL;
3028
3029                         idx = osc_index(ops);
3030                         if (idx > end) {
3031                                 end_of_region = true;
3032                                 break;
3033                         }
3034
3035                         page = ops->ops_cl.cpl_page;
3036                         LASSERT(page->cp_type == CPT_CACHEABLE);
3037                         if (page->cp_state == CPS_FREEING)
3038                                 continue;
3039
3040                         cl_page_get(page);
3041                         lu_ref_add_atomic(&page->cp_reference,
3042                                           "gang_lookup", current);
3043                         pvec[j++] = ops;
3044                 }
3045                 ++idx;
3046
3047                 /*
3048                  * Here a delicate locking dance is performed. Current thread
3049                  * holds a reference to a page, but has to own it before it
3050                  * can be placed into queue. Owning implies waiting, so
3051                  * radix-tree lock is to be released. After a wait one has to
3052                  * check that pages weren't truncated (cl_page_own() returns
3053                  * error in the latter case).
3054                  */
3055                 spin_unlock(&osc->oo_tree_lock);
3056                 tree_lock = false;
3057
3058                 for (i = 0; i < j; ++i) {
3059                         ops = pvec[i];
3060                         if (res == CLP_GANG_OKAY)
3061                                 res = (*cb)(env, io, ops, cbdata);
3062
3063                         page = ops->ops_cl.cpl_page;
3064                         lu_ref_del(&page->cp_reference, "gang_lookup", current);
3065                         cl_page_put(env, page);
3066                 }
3067                 if (nr < OTI_PVEC_SIZE || end_of_region)
3068                         break;
3069
3070                 if (res == CLP_GANG_OKAY && need_resched())
3071                         res = CLP_GANG_RESCHED;
3072                 if (res != CLP_GANG_OKAY)
3073                         break;
3074
3075                 spin_lock(&osc->oo_tree_lock);
3076                 tree_lock = true;
3077         }
3078         if (tree_lock)
3079                 spin_unlock(&osc->oo_tree_lock);
3080         RETURN(res);
3081 }
3082
3083 /**
3084  * Check if page @page is covered by an extra lock or discard it.
3085  */
3086 static int check_and_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 osc_object *osc = cbdata;
3091         pgoff_t index;
3092
3093         index = osc_index(ops);
3094         if (index >= info->oti_fn_index) {
3095                 struct ldlm_lock *tmp;
3096                 struct cl_page *page = ops->ops_cl.cpl_page;
3097
3098                 /* refresh non-overlapped index */
3099                 tmp = osc_dlmlock_at_pgoff(env, osc, index, 0, 0);
3100                 if (tmp != NULL) {
3101                         __u64 end = tmp->l_policy_data.l_extent.end;
3102                         /* Cache the first-non-overlapped index so as to skip
3103                          * all pages within [index, oti_fn_index). This is safe
3104                          * because if tmp lock is canceled, it will discard
3105                          * these pages. */
3106                         info->oti_fn_index = cl_index(osc2cl(osc), end + 1);
3107                         if (end == OBD_OBJECT_EOF)
3108                                 info->oti_fn_index = CL_PAGE_EOF;
3109                         LDLM_LOCK_PUT(tmp);
3110                 } else if (cl_page_own(env, io, page) == 0) {
3111                         /* discard the page */
3112                         cl_page_discard(env, io, page);
3113                         cl_page_disown(env, io, page);
3114                 } else {
3115                         LASSERT(page->cp_state == CPS_FREEING);
3116                 }
3117         }
3118
3119         info->oti_next_index = index + 1;
3120         return CLP_GANG_OKAY;
3121 }
3122
3123 static int discard_cb(const struct lu_env *env, struct cl_io *io,
3124                       struct osc_page *ops, void *cbdata)
3125 {
3126         struct osc_thread_info *info = osc_env_info(env);
3127         struct cl_page *page = ops->ops_cl.cpl_page;
3128
3129         /* page is top page. */
3130         info->oti_next_index = osc_index(ops) + 1;
3131         if (cl_page_own(env, io, page) == 0) {
3132                 KLASSERT(ergo(page->cp_type == CPT_CACHEABLE,
3133                               !PageDirty(cl_page_vmpage(page))));
3134
3135                 /* discard the page */
3136                 cl_page_discard(env, io, page);
3137                 cl_page_disown(env, io, page);
3138         } else {
3139                 LASSERT(page->cp_state == CPS_FREEING);
3140         }
3141
3142         return CLP_GANG_OKAY;
3143 }
3144
3145 /**
3146  * Discard pages protected by the given lock. This function traverses radix
3147  * tree to find all covering pages and discard them. If a page is being covered
3148  * by other locks, it should remain in cache.
3149  *
3150  * If error happens on any step, the process continues anyway (the reasoning
3151  * behind this being that lock cancellation cannot be delayed indefinitely).
3152  */
3153 int osc_lock_discard_pages(const struct lu_env *env, struct osc_object *osc,
3154                            pgoff_t start, pgoff_t end, enum cl_lock_mode mode)
3155 {
3156         struct osc_thread_info *info = osc_env_info(env);
3157         struct cl_io *io = &info->oti_io;
3158         osc_page_gang_cbt cb;
3159         int res;
3160         int result;
3161
3162         ENTRY;
3163
3164         io->ci_obj = cl_object_top(osc2cl(osc));
3165         io->ci_ignore_layout = 1;
3166         result = cl_io_init(env, io, CIT_MISC, io->ci_obj);
3167         if (result != 0)
3168                 GOTO(out, result);
3169
3170         cb = mode == CLM_READ ? check_and_discard_cb : discard_cb;
3171         info->oti_fn_index = info->oti_next_index = start;
3172         do {
3173                 res = osc_page_gang_lookup(env, io, osc,
3174                                            info->oti_next_index, end, cb, osc);
3175                 if (info->oti_next_index > end)
3176                         break;
3177
3178                 if (res == CLP_GANG_RESCHED)
3179                         cond_resched();
3180         } while (res != CLP_GANG_OKAY);
3181 out:
3182         cl_io_fini(env, io);
3183         RETURN(result);
3184 }
3185
3186
3187 /** @} osc */