lustre/osc/osc_cache.c

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see
  18  * http://www.gnu.org/licenses/gpl-2.0.html
  19  *
  20  * GPL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  24  * Use is subject to license terms.
  25  *
  26  * Copyright (c) 2012, 2017, Intel Corporation.
  27  *
  28  */
  29 /*
  30  * This file is part of Lustre, http://www.lustre.org/
  31  *
  32  * osc cache management.
  33  *
  34  * Author: Jinshan Xiong <jinshan.xiong@whamcloud.com>
  35  */
  36
  37 #define DEBUG_SUBSYSTEM S_OSC
  38
  39 #include <lustre_osc.h>
  40 #include <lustre_dlm.h>
  41
  42 #include "osc_internal.h"
  43
  44 static int extent_debug; /* set it to be true for more debug */
  45
  46 static void osc_update_pending(struct osc_object *obj, int cmd, int delta);
  47 static int osc_extent_wait(const struct lu_env *env, struct osc_extent *ext,
  48                            enum osc_extent_state state);
  49 static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
  50                               struct osc_async_page *oap, int sent, int rc);
  51 static int osc_make_ready(const struct lu_env *env, struct osc_async_page *oap,
  52                           int cmd);
  53 static int osc_refresh_count(const struct lu_env *env,
  54                              struct osc_async_page *oap, int cmd);
  55 static int osc_io_unplug_async(const struct lu_env *env,
  56                                struct client_obd *cli, struct osc_object *osc);
  57 static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
  58                            unsigned int lost_grant, unsigned int dirty_grant);
  59
  60 static void osc_extent_tree_dump0(int mask, struct osc_object *obj,
  61                                   const char *func, int line);
  62 #define osc_extent_tree_dump(mask, obj) \
  63         osc_extent_tree_dump0(mask, obj, __func__, __LINE__)
  64
  65 static void osc_unreserve_grant(struct client_obd *cli, unsigned int reserved,
  66                                 unsigned int unused);
  67
  68 /** \addtogroup osc
  69  *  @{
  70  */
  71
  72 /* ------------------ osc extent ------------------ */
  73 static inline char *ext_flags(struct osc_extent *ext, char *flags)
  74 {
  75         char *buf = flags;
  76         *buf++ = ext->oe_rw ? 'r' : 'w';
  77         if (!RB_EMPTY_NODE(&ext->oe_node))
  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 #define EXTSTR       "[%lu -> %lu/%lu]"
  98 #define EXTPARA(ext) (ext)->oe_start, (ext)->oe_end, (ext)->oe_max_end
  99 static const char *const oes_strings[] = {
 100         "inv", "active", "cache", "locking", "lockdone", "rpc", "trunc", NULL };
 101
 102 #define OSC_EXTENT_DUMP_WITH_LOC(file, func, line, mask, extent, fmt, ...) do {\
 103         static struct cfs_debug_limit_state cdls;                             \
 104         struct osc_extent *__ext = (extent);                                  \
 105         char __buf[16];                                                       \
 106                                                                               \
 107         __CDEBUG_WITH_LOC(file, func, line, mask, &cdls,                      \
 108                 "extent %p@{" EXTSTR ", "                                     \
 109                 "[%d|%d|%c|%s|%s|%p], [%d|%d|%c|%c|%p|%u|%p]} " fmt,          \
 110                 /* ----- extent part 0 ----- */                               \
 111                 __ext, EXTPARA(__ext),                                        \
 112                 /* ----- part 1 ----- */                                      \
 113                 kref_read(&__ext->oe_refc),                                   \
 114                 atomic_read(&__ext->oe_users),                                \
 115                 list_empty_marker(&__ext->oe_link),                           \
 116                 oes_strings[__ext->oe_state], ext_flags(__ext, __buf),        \
 117                 __ext->oe_obj,                                                \
 118                 /* ----- part 2 ----- */                                      \
 119                 __ext->oe_grants, __ext->oe_nr_pages,                         \
 120                 list_empty_marker(&__ext->oe_pages),                          \
 121                 waitqueue_active(&__ext->oe_waitq) ? '+' : '-',               \
 122                 __ext->oe_dlmlock, __ext->oe_mppr, __ext->oe_owner,           \
 123                 /* ----- part 4 ----- */                                      \
 124                 ## __VA_ARGS__);                                              \
 125         if (mask == D_ERROR && __ext->oe_dlmlock != NULL)                     \
 126                 LDLM_ERROR(__ext->oe_dlmlock, "extent: %p", __ext);           \
 127         else                                                                  \
 128                 LDLM_DEBUG(__ext->oe_dlmlock, "extent: %p", __ext);           \
 129 } while (0)
 130
 131 #define OSC_EXTENT_DUMP(mask, ext, fmt, ...)                            \
 132         OSC_EXTENT_DUMP_WITH_LOC(__FILE__, __func__, __LINE__,          \
 133                                  mask, ext, fmt, ## __VA_ARGS__)
 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         return rb_entry_safe(n, struct osc_extent, oe_node);
 150 }
 151
 152 static inline struct osc_extent *next_extent(struct osc_extent *ext)
 153 {
 154         if (ext == NULL)
 155                 return NULL;
 156
 157         LASSERT(!RB_EMPTY_NODE(&ext->oe_node));
 158         return rb_extent(rb_next(&ext->oe_node));
 159 }
 160
 161 static inline struct osc_extent *prev_extent(struct osc_extent *ext)
 162 {
 163         if (ext == NULL)
 164                 return NULL;
 165
 166         LASSERT(!RB_EMPTY_NODE(&ext->oe_node));
 167         return rb_extent(rb_prev(&ext->oe_node));
 168 }
 169
 170 static inline struct osc_extent *first_extent(struct osc_object *obj)
 171 {
 172         return rb_extent(rb_first(&obj->oo_root));
 173 }
 174
 175 /* object must be locked by caller. */
 176 static int osc_extent_sanity_check0(struct osc_extent *ext,
 177                                     const char *func, const int line)
 178 {
 179         struct osc_object *obj = ext->oe_obj;
 180         struct osc_async_page *oap;
 181         size_t page_count;
 182         int rc = 0;
 183
 184         assert_osc_object_is_locked(obj);
 185
 186         if (ext->oe_state >= OES_STATE_MAX)
 187                 GOTO(out, rc = 10);
 188
 189         if (kref_read(&ext->oe_refc) <= 0)
 190                 GOTO(out, rc = 20);
 191
 192         if (kref_read(&ext->oe_refc) < atomic_read(&ext->oe_users))
 193                 GOTO(out, rc = 30);
 194
 195         switch (ext->oe_state) {
 196         case OES_INV:
 197                 if (ext->oe_nr_pages > 0 || !list_empty(&ext->oe_pages))
 198                         GOTO(out, rc = 35);
 199                 GOTO(out, rc = 0);
 200                 break;
 201         case OES_ACTIVE:
 202                 if (atomic_read(&ext->oe_users) == 0)
 203                         GOTO(out, rc = 40);
 204                 if (ext->oe_hp)
 205                         GOTO(out, rc = 50);
 206                 if (ext->oe_fsync_wait && !ext->oe_urgent)
 207                         GOTO(out, rc = 55);
 208                 break;
 209         case OES_CACHE:
 210                 if (ext->oe_grants == 0)
 211                         GOTO(out, rc = 60);
 212                 if (ext->oe_fsync_wait && !ext->oe_urgent && !ext->oe_hp)
 213                         GOTO(out, rc = 65);
 214                 fallthrough;
 215         default:
 216                 if (atomic_read(&ext->oe_users) > 0)
 217                         GOTO(out, rc = 70);
 218         }
 219
 220         if (ext->oe_max_end < ext->oe_end || ext->oe_end < ext->oe_start)
 221                 GOTO(out, rc = 80);
 222
 223         if (ext->oe_sync && ext->oe_grants > 0)
 224                 GOTO(out, rc = 90);
 225
 226         if (ext->oe_dlmlock != NULL &&
 227             ext->oe_dlmlock->l_resource->lr_type == LDLM_EXTENT &&
 228             !ldlm_is_failed(ext->oe_dlmlock)) {
 229                 struct ldlm_extent *extent;
 230
 231                 extent = &ext->oe_dlmlock->l_policy_data.l_extent;
 232                 if (!(extent->start <= ext->oe_start << PAGE_SHIFT &&
 233                       extent->end >= ext->oe_max_end << PAGE_SHIFT))
 234                         GOTO(out, rc = 100);
 235
 236                 if (!(ext->oe_dlmlock->l_granted_mode & (LCK_PW | LCK_GROUP)))
 237                         GOTO(out, rc = 102);
 238         }
 239
 240         if (ext->oe_nr_pages > ext->oe_mppr)
 241                 GOTO(out, rc = 105);
 242
 243         /* Do not verify page list if extent is in RPC. This is because an
 244          * in-RPC extent is supposed to be exclusively accessible w/o lock. */
 245         if (ext->oe_state > OES_CACHE)
 246                 GOTO(out, rc = 0);
 247
 248         if (!extent_debug)
 249                 GOTO(out, rc = 0);
 250
 251         page_count = 0;
 252         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
 253                 pgoff_t index = osc_index(oap2osc(oap));
 254                 ++page_count;
 255                 if (index > ext->oe_end || index < ext->oe_start)
 256                         GOTO(out, rc = 110);
 257         }
 258         if (page_count != ext->oe_nr_pages)
 259                 GOTO(out, rc = 120);
 260
 261 out:
 262         if (rc != 0)
 263                 OSC_EXTENT_DUMP_WITH_LOC(__FILE__, func, line, D_ERROR, ext,
 264                                          "sanity check %p failed: rc = %d\n",
 265                                          ext, rc);
 266         return rc;
 267 }
 268
 269 #define sanity_check_nolock(ext) \
 270         osc_extent_sanity_check0(ext, __func__, __LINE__)
 271
 272 #define sanity_check(ext) ({                                                   \
 273         int __res;                                                             \
 274         osc_object_lock((ext)->oe_obj);                                        \
 275         __res = sanity_check_nolock(ext);                                      \
 276         osc_object_unlock((ext)->oe_obj);                                      \
 277         __res;                                                                 \
 278 })
 279
 280 static inline bool
 281 overlapped(const struct osc_extent *ex1, const struct osc_extent *ex2)
 282 {
 283         return !(ex1->oe_end < ex2->oe_start || ex2->oe_end < ex1->oe_start);
 284 }
 285
 286 /**
 287  * sanity check - to make sure there is no overlapped extent in the tree.
 288  */
 289 static int osc_extent_is_overlapped(struct osc_object *obj,
 290                                     struct osc_extent *ext)
 291 {
 292         struct osc_extent *tmp;
 293
 294         assert_osc_object_is_locked(obj);
 295
 296         if (!extent_debug)
 297                 return 0;
 298
 299         for (tmp = first_extent(obj); tmp != NULL; tmp = next_extent(tmp)) {
 300                 if (tmp == ext)
 301                         continue;
 302                 if (overlapped(tmp, ext))
 303                         return 1;
 304         }
 305         return 0;
 306 }
 307
 308 static void osc_extent_state_set(struct osc_extent *ext, int state)
 309 {
 310         assert_osc_object_is_locked(ext->oe_obj);
 311         LASSERT(state >= OES_INV && state < OES_STATE_MAX);
 312
 313         /* Never try to sanity check a state changing extent :-) */
 314         /* LASSERT(sanity_check_nolock(ext) == 0); */
 315
 316         /* TODO: validate the state machine */
 317         smp_store_release(&ext->oe_state, state);
 318         wake_up(&ext->oe_waitq);
 319 }
 320
 321 static struct osc_extent *osc_extent_alloc(struct osc_object *obj)
 322 {
 323         struct osc_extent *ext;
 324
 325         OBD_SLAB_ALLOC_PTR_GFP(ext, osc_extent_kmem, GFP_NOFS);
 326         if (ext == NULL)
 327                 return NULL;
 328
 329         RB_CLEAR_NODE(&ext->oe_node);
 330         ext->oe_obj = obj;
 331         cl_object_get(osc2cl(obj));
 332         kref_init(&ext->oe_refc);
 333         atomic_set(&ext->oe_users, 0);
 334         INIT_LIST_HEAD(&ext->oe_link);
 335         ext->oe_state = OES_INV;
 336         INIT_LIST_HEAD(&ext->oe_pages);
 337         init_waitqueue_head(&ext->oe_waitq);
 338         ext->oe_dlmlock = NULL;
 339
 340         return ext;
 341 }
 342
 343 static void osc_extent_free(struct kref *kref)
 344 {
 345         struct osc_extent *ext = container_of(kref, struct osc_extent,
 346                                               oe_refc);
 347
 348         LASSERT(list_empty(&ext->oe_link));
 349         LASSERT(atomic_read(&ext->oe_users) == 0);
 350         LASSERT(ext->oe_state == OES_INV);
 351         LASSERT(RB_EMPTY_NODE(&ext->oe_node));
 352
 353         if (ext->oe_dlmlock) {
 354                 lu_ref_del(&ext->oe_dlmlock->l_reference,
 355                            "osc_extent", ext);
 356                 LDLM_LOCK_PUT(ext->oe_dlmlock);
 357                 ext->oe_dlmlock = NULL;
 358         }
 359 #if 0
 360         /* If/When cl_object_put drops the need for 'env',
 361          * this code can be enabled, and matching code in
 362          * osc_extent_put removed.
 363          */
 364         cl_object_put(osc2cl(ext->oe_obj));
 365
 366         OBD_SLAB_FREE_PTR(ext, osc_extent_kmem);
 367 #endif
 368 }
 369
 370 static struct osc_extent *osc_extent_get(struct osc_extent *ext)
 371 {
 372         LASSERT(kref_read(&ext->oe_refc) >= 0);
 373         kref_get(&ext->oe_refc);
 374         return ext;
 375 }
 376
 377 static void osc_extent_put(const struct lu_env *env, struct osc_extent *ext)
 378 {
 379         LASSERT(kref_read(&ext->oe_refc) > 0);
 380         if (kref_put(&ext->oe_refc, osc_extent_free)) {
 381                 /* This should be in osc_extent_free(), but
 382                  * while we need to pass 'env' it cannot be.
 383                  */
 384                 cl_object_put(env, osc2cl(ext->oe_obj));
 385
 386                 OBD_SLAB_FREE_PTR(ext, osc_extent_kmem);
 387         }
 388 }
 389
 390 /**
 391  * osc_extent_put_trust() is a special version of osc_extent_put() when
 392  * it's known that the caller is not the last user. This is to address the
 393  * problem of lacking of lu_env ;-).
 394  */
 395 static void osc_extent_put_trust(struct osc_extent *ext)
 396 {
 397         LASSERT(kref_read(&ext->oe_refc) > 1);
 398         assert_osc_object_is_locked(ext->oe_obj);
 399         osc_extent_put(NULL, ext);
 400 }
 401
 402 /**
 403  * Return the extent which includes pgoff @index, or return the greatest
 404  * previous extent in the tree.
 405  */
 406 static struct osc_extent *osc_extent_search(struct osc_object *obj,
 407                                             pgoff_t index)
 408 {
 409         struct rb_node    *n = obj->oo_root.rb_node;
 410         struct osc_extent *tmp, *p = NULL;
 411
 412         assert_osc_object_is_locked(obj);
 413         while (n != NULL) {
 414                 tmp = rb_extent(n);
 415                 if (index < tmp->oe_start) {
 416                         n = n->rb_left;
 417                 } else if (index > tmp->oe_end) {
 418                         p = rb_extent(n);
 419                         n = n->rb_right;
 420                 } else {
 421                         return tmp;
 422                 }
 423         }
 424         return p;
 425 }
 426
 427 /*
 428  * Return the extent covering @index, otherwise return NULL.
 429  * caller must have held object lock.
 430  */
 431 static struct osc_extent *osc_extent_lookup(struct osc_object *obj,
 432                                             pgoff_t index)
 433 {
 434         struct osc_extent *ext;
 435
 436         ext = osc_extent_search(obj, index);
 437         if (ext != NULL && ext->oe_start <= index && index <= ext->oe_end)
 438                 return osc_extent_get(ext);
 439         return NULL;
 440 }
 441
 442 /* caller must have held object lock. */
 443 static void osc_extent_insert(struct osc_object *obj, struct osc_extent *ext)
 444 {
 445         struct rb_node   **n      = &obj->oo_root.rb_node;
 446         struct rb_node    *parent = NULL;
 447         struct osc_extent *tmp;
 448
 449         LASSERT(RB_EMPTY_NODE(&ext->oe_node));
 450         LASSERT(ext->oe_obj == obj);
 451         assert_osc_object_is_locked(obj);
 452         while (*n != NULL) {
 453                 tmp = rb_extent(*n);
 454                 parent = *n;
 455
 456                 if (ext->oe_end < tmp->oe_start)
 457                         n = &(*n)->rb_left;
 458                 else if (ext->oe_start > tmp->oe_end)
 459                         n = &(*n)->rb_right;
 460                 else
 461                         EASSERTF(0, tmp, EXTSTR"\n", EXTPARA(ext));
 462         }
 463         rb_link_node(&ext->oe_node, parent, n);
 464         rb_insert_color(&ext->oe_node, &obj->oo_root);
 465         osc_extent_get(ext);
 466 }
 467
 468 /* caller must have held object lock. */
 469 static void osc_extent_erase(struct osc_extent *ext)
 470 {
 471         struct osc_object *obj = ext->oe_obj;
 472         assert_osc_object_is_locked(obj);
 473         if (!RB_EMPTY_NODE(&ext->oe_node)) {
 474                 rb_erase(&ext->oe_node, &obj->oo_root);
 475                 RB_CLEAR_NODE(&ext->oe_node);
 476                 /* rbtree held a refcount */
 477                 osc_extent_put_trust(ext);
 478         }
 479 }
 480
 481 static struct osc_extent *osc_extent_hold(struct osc_extent *ext)
 482 {
 483         struct osc_object *obj = ext->oe_obj;
 484
 485         assert_osc_object_is_locked(obj);
 486         LASSERT(ext->oe_state == OES_ACTIVE || ext->oe_state == OES_CACHE);
 487         if (ext->oe_state == OES_CACHE) {
 488                 osc_extent_state_set(ext, OES_ACTIVE);
 489                 osc_update_pending(obj, OBD_BRW_WRITE, -ext->oe_nr_pages);
 490         }
 491         atomic_inc(&ext->oe_users);
 492         list_del_init(&ext->oe_link);
 493         return osc_extent_get(ext);
 494 }
 495
 496 static void __osc_extent_remove(struct osc_extent *ext)
 497 {
 498         assert_osc_object_is_locked(ext->oe_obj);
 499         LASSERT(list_empty(&ext->oe_pages));
 500         osc_extent_erase(ext);
 501         list_del_init(&ext->oe_link);
 502         osc_extent_state_set(ext, OES_INV);
 503         OSC_EXTENT_DUMP(D_CACHE, ext, "destroyed.\n");
 504 }
 505
 506 static void osc_extent_remove(struct osc_extent *ext)
 507 {
 508         struct osc_object *obj = ext->oe_obj;
 509
 510         osc_object_lock(obj);
 511         __osc_extent_remove(ext);
 512         osc_object_unlock(obj);
 513 }
 514
 515 /**
 516  * This function is used to merge extents to get better performance. It checks
 517  * if @cur and @victim are contiguous at block level.
 518  */
 519 static int osc_extent_merge(const struct lu_env *env, struct osc_extent *cur,
 520                             struct osc_extent *victim)
 521 {
 522         struct osc_object       *obj = cur->oe_obj;
 523         struct client_obd       *cli = osc_cli(obj);
 524         pgoff_t                  chunk_start;
 525         pgoff_t                  chunk_end;
 526         int                      ppc_bits;
 527
 528         LASSERT(cur->oe_state == OES_CACHE);
 529         assert_osc_object_is_locked(obj);
 530         if (victim == NULL)
 531                 return -EINVAL;
 532
 533         if (victim->oe_state != OES_INV &&
 534             (victim->oe_state != OES_CACHE || victim->oe_fsync_wait))
 535                 return -EBUSY;
 536
 537         if (cur->oe_max_end != victim->oe_max_end)
 538                 return -ERANGE;
 539
 540         /*
 541          * In the rare case max_pages_per_rpc (mppr) is changed, don't
 542          * merge extents until after old ones have been sent, or the
 543          * "extents are aligned to RPCs" checks are unhappy.
 544          */
 545         if (cur->oe_mppr != victim->oe_mppr)
 546                 return -ERANGE;
 547
 548         LASSERT(cur->oe_dlmlock == victim->oe_dlmlock);
 549         ppc_bits = osc_cli(obj)->cl_chunkbits - PAGE_SHIFT;
 550         chunk_start = cur->oe_start >> ppc_bits;
 551         chunk_end   = cur->oe_end   >> ppc_bits;
 552         if (chunk_start   != (victim->oe_end >> ppc_bits) + 1 &&
 553             chunk_end + 1 != victim->oe_start >> ppc_bits)
 554                 return -ERANGE;
 555
 556         /* overall extent size should not exceed the max supported limit
 557          * reported by the server */
 558         if (cur->oe_end - cur->oe_start + 1 +
 559             victim->oe_end - victim->oe_start + 1 > cli->cl_max_extent_pages)
 560                 return -ERANGE;
 561
 562         OSC_EXTENT_DUMP(D_CACHE, victim, "will be merged by %p.\n", cur);
 563
 564         cur->oe_start     = min(cur->oe_start, victim->oe_start);
 565         cur->oe_end       = max(cur->oe_end,   victim->oe_end);
 566         /* per-extent tax should be accounted only once for the whole extent */
 567         cur->oe_grants   += victim->oe_grants - cli->cl_grant_extent_tax;
 568         cur->oe_nr_pages += victim->oe_nr_pages;
 569         /* only the following bits are needed to merge */
 570         cur->oe_urgent   |= victim->oe_urgent;
 571         cur->oe_memalloc |= victim->oe_memalloc;
 572         list_splice_init(&victim->oe_pages, &cur->oe_pages);
 573         victim->oe_nr_pages = 0;
 574
 575         osc_extent_get(victim);
 576         __osc_extent_remove(victim);
 577         osc_extent_put(env, victim);
 578
 579         OSC_EXTENT_DUMP(D_CACHE, cur, "after merging %p.\n", victim);
 580         return 0;
 581 }
 582
 583 /**
 584  * Drop user count of osc_extent, and unplug IO asynchronously.
 585  */
 586 void osc_extent_release(const struct lu_env *env, struct osc_extent *ext)
 587 {
 588         struct osc_object *obj = ext->oe_obj;
 589         struct client_obd *cli = osc_cli(obj);
 590         ENTRY;
 591
 592         LASSERT(atomic_read(&ext->oe_users) > 0);
 593         LASSERT(sanity_check(ext) == 0);
 594         LASSERT(ext->oe_grants > 0);
 595
 596         if (atomic_dec_and_lock(&ext->oe_users, &obj->oo_lock)) {
 597                 LASSERT(ext->oe_state == OES_ACTIVE);
 598                 if (ext->oe_trunc_pending) {
 599                         /* a truncate process is waiting for this extent.
 600                          * This may happen due to a race, check
 601                          * osc_cache_truncate_start(). */
 602                         osc_extent_state_set(ext, OES_TRUNC);
 603                         ext->oe_trunc_pending = 0;
 604                         osc_object_unlock(obj);
 605                 } else {
 606                         int grant = 0;
 607
 608                         osc_extent_state_set(ext, OES_CACHE);
 609                         osc_update_pending(obj, OBD_BRW_WRITE,
 610                                            ext->oe_nr_pages);
 611
 612                         /* try to merge the previous and next extent. */
 613                         if (osc_extent_merge(env, ext, prev_extent(ext)) == 0)
 614                                 grant += cli->cl_grant_extent_tax;
 615                         if (osc_extent_merge(env, ext, next_extent(ext)) == 0)
 616                                 grant += cli->cl_grant_extent_tax;
 617
 618                         if (ext->oe_hp)
 619                                 list_move_tail(&ext->oe_link,
 620                                                &obj->oo_hp_exts);
 621                         else if (ext->oe_urgent)
 622                                 list_move_tail(&ext->oe_link,
 623                                                &obj->oo_urgent_exts);
 624                         else if (ext->oe_nr_pages == ext->oe_mppr) {
 625                                 list_move_tail(&ext->oe_link,
 626                                                &obj->oo_full_exts);
 627                         }
 628                         osc_object_unlock(obj);
 629                         if (grant > 0)
 630                                 osc_unreserve_grant(cli, 0, grant);
 631                 }
 632
 633                 osc_io_unplug_async(env, cli, obj);
 634         }
 635         osc_extent_put(env, ext);
 636
 637         RETURN_EXIT;
 638 }
 639
 640 /**
 641  * Find or create an extent which includes @index, core function to manage
 642  * extent tree.
 643  */
 644 static struct osc_extent *osc_extent_find(const struct lu_env *env,
 645                                           struct osc_object *obj, pgoff_t index,
 646                                           unsigned int *grants)
 647 {
 648         struct client_obd *cli = osc_cli(obj);
 649         struct osc_lock   *olck;
 650         struct cl_lock_descr *descr;
 651         struct osc_extent *cur;
 652         struct osc_extent *ext;
 653         struct osc_extent *conflict = NULL;
 654         struct osc_extent *found = NULL;
 655         pgoff_t    chunk;
 656         pgoff_t    max_end;
 657         unsigned int max_pages; /* max_pages_per_rpc */
 658         unsigned int chunksize;
 659         int        ppc_bits; /* pages per chunk bits */
 660         pgoff_t    chunk_mask;
 661         int        rc;
 662         ENTRY;
 663
 664         cur = osc_extent_alloc(obj);
 665         if (cur == NULL)
 666                 RETURN(ERR_PTR(-ENOMEM));
 667
 668         olck = osc_env_io(env)->oi_write_osclock;
 669         LASSERTF(olck != NULL, "page %lu is not covered by lock\n", index);
 670         LASSERT(olck->ols_state == OLS_GRANTED);
 671
 672         descr = &olck->ols_cl.cls_lock->cll_descr;
 673         LASSERT(descr->cld_mode >= CLM_WRITE);
 674
 675         LASSERTF(cli->cl_chunkbits >= PAGE_SHIFT,
 676                  "chunkbits: %u\n", cli->cl_chunkbits);
 677         ppc_bits   = cli->cl_chunkbits - PAGE_SHIFT;
 678         chunk_mask = ~((1 << ppc_bits) - 1);
 679         chunksize  = 1 << cli->cl_chunkbits;
 680         chunk      = index >> ppc_bits;
 681
 682         /* align end to RPC edge. */
 683         max_pages = cli->cl_max_pages_per_rpc;
 684         if ((max_pages & ~chunk_mask) != 0) {
 685                 CERROR("max_pages: %#x chunkbits: %u chunk_mask: %#lx\n",
 686                        max_pages, cli->cl_chunkbits, chunk_mask);
 687                 RETURN(ERR_PTR(-EINVAL));
 688         }
 689         max_end = index - (index % max_pages) + max_pages - 1;
 690         max_end = min_t(pgoff_t, max_end, descr->cld_end);
 691
 692         /* initialize new extent by parameters so far */
 693         cur->oe_max_end = max_end;
 694         cur->oe_start   = index & chunk_mask;
 695         cur->oe_end     = ((index + ~chunk_mask + 1) & chunk_mask) - 1;
 696         if (cur->oe_start < descr->cld_start)
 697                 cur->oe_start = descr->cld_start;
 698         if (cur->oe_end > max_end)
 699                 cur->oe_end = max_end;
 700         cur->oe_grants  = chunksize + cli->cl_grant_extent_tax;
 701         cur->oe_mppr    = max_pages;
 702         if (olck->ols_dlmlock != NULL) {
 703                 LASSERT(olck->ols_hold);
 704                 cur->oe_dlmlock = LDLM_LOCK_GET(olck->ols_dlmlock);
 705                 lu_ref_add(&olck->ols_dlmlock->l_reference, "osc_extent", cur);
 706         }
 707
 708         /* grants has been allocated by caller */
 709         LASSERTF(*grants >= chunksize + cli->cl_grant_extent_tax,
 710                  "%u/%u/%u.\n", *grants, chunksize, cli->cl_grant_extent_tax);
 711         LASSERTF((max_end - cur->oe_start) < max_pages, EXTSTR"\n",
 712                  EXTPARA(cur));
 713
 714 restart:
 715         osc_object_lock(obj);
 716         ext = osc_extent_search(obj, cur->oe_start);
 717         if (!ext)
 718                 ext = first_extent(obj);
 719         for (; ext; ext = next_extent(ext)) {
 720                 pgoff_t ext_chk_start = ext->oe_start >> ppc_bits;
 721                 pgoff_t ext_chk_end = ext->oe_end >> ppc_bits;
 722
 723                 LASSERT(sanity_check_nolock(ext) == 0);
 724                 if (chunk > ext_chk_end + 1 || chunk < ext_chk_start)
 725                         break;
 726
 727                 /* if covering by different locks, no chance to match */
 728                 if (olck->ols_dlmlock != ext->oe_dlmlock) {
 729                         EASSERTF(!overlapped(ext, cur), ext,
 730                                  EXTSTR"\n", EXTPARA(cur));
 731
 732                         continue;
 733                 }
 734
 735                 /* discontiguous chunks? */
 736                 if (chunk + 1 < ext_chk_start)
 737                         continue;
 738
 739                 /* ok, from now on, ext and cur have these attrs:
 740                  * 1. covered by the same lock
 741                  * 2. contiguous at chunk level or overlapping. */
 742
 743                 if (overlapped(ext, cur)) {
 744                         /* cur is the minimum unit, so overlapping means
 745                          * full contain. */
 746                         EASSERTF((ext->oe_start <= cur->oe_start &&
 747                                   ext->oe_end >= cur->oe_end),
 748                                  ext, EXTSTR"\n", EXTPARA(cur));
 749
 750                         if (ext->oe_state > OES_CACHE || ext->oe_fsync_wait) {
 751                                 /* for simplicity, we wait for this extent to
 752                                  * finish before going forward. */
 753                                 conflict = osc_extent_get(ext);
 754                                 break;
 755                         }
 756
 757                         found = osc_extent_hold(ext);
 758                         break;
 759                 }
 760
 761                 /* non-overlapped extent */
 762                 if (ext->oe_state != OES_CACHE || ext->oe_fsync_wait)
 763                         /* we can't do anything for a non OES_CACHE extent, or
 764                          * if there is someone waiting for this extent to be
 765                          * flushed, try next one. */
 766                         continue;
 767
 768                 if (osc_extent_merge(env, ext, cur) == 0) {
 769                         LASSERT(*grants >= chunksize);
 770                         *grants -= chunksize;
 771
 772                         /*
 773                          * Try to merge with the next one too because we
 774                          * might have just filled in a gap.
 775                          */
 776                         if (osc_extent_merge(env, ext, next_extent(ext)) == 0)
 777                                 /* we can save extent tax from next extent */
 778                                 *grants += cli->cl_grant_extent_tax;
 779
 780                         found = osc_extent_hold(ext);
 781                         break;
 782                 }
 783         }
 784
 785         osc_extent_tree_dump(D_CACHE, obj);
 786         if (found != NULL) {
 787                 LASSERT(conflict == NULL);
 788                 if (!IS_ERR(found)) {
 789                         LASSERT(found->oe_dlmlock == cur->oe_dlmlock);
 790                         OSC_EXTENT_DUMP(D_CACHE, found,
 791                                         "found caching ext for %lu.\n", index);
 792                 }
 793         } else if (conflict == NULL) {
 794                 /* create a new extent */
 795                 EASSERT(osc_extent_is_overlapped(obj, cur) == 0, cur);
 796                 LASSERT(*grants >= cur->oe_grants);
 797                 *grants -= cur->oe_grants;
 798
 799                 cur->oe_state = OES_CACHE;
 800                 found = osc_extent_hold(cur);
 801                 osc_extent_insert(obj, cur);
 802                 OSC_EXTENT_DUMP(D_CACHE, cur, "add into tree %lu/%lu.\n",
 803                                 index, descr->cld_end);
 804         }
 805         osc_object_unlock(obj);
 806
 807         if (conflict != NULL) {
 808                 LASSERT(found == NULL);
 809
 810                 /* waiting for IO to finish. Please notice that it's impossible
 811                  * to be an OES_TRUNC extent. */
 812                 rc = osc_extent_wait(env, conflict, OES_INV);
 813                 osc_extent_put(env, conflict);
 814                 conflict = NULL;
 815                 if (rc < 0)
 816                         GOTO(out, found = ERR_PTR(rc));
 817
 818                 goto restart;
 819         }
 820         EXIT;
 821
 822 out:
 823         osc_extent_put(env, cur);
 824         return found;
 825 }
 826
 827 /**
 828  * Called when IO is finished to an extent.
 829  */
 830 int osc_extent_finish(const struct lu_env *env, struct osc_extent *ext,
 831                       int sent, int rc)
 832 {
 833         struct client_obd *cli = osc_cli(ext->oe_obj);
 834         struct osc_async_page *oap;
 835         struct osc_async_page *tmp;
 836         int nr_pages = ext->oe_nr_pages;
 837         int lost_grant = 0;
 838         int blocksize = cli->cl_import->imp_obd->obd_osfs.os_bsize ? : 4096;
 839         loff_t last_off = 0;
 840         int last_count = -1;
 841         ENTRY;
 842
 843         OSC_EXTENT_DUMP(D_CACHE, ext, "extent finished.\n");
 844
 845         ext->oe_rc = rc ?: ext->oe_nr_pages;
 846         EASSERT(ergo(rc == 0, ext->oe_state == OES_RPC), ext);
 847
 848         osc_lru_add_batch(cli, &ext->oe_pages);
 849         list_for_each_entry_safe(oap, tmp, &ext->oe_pages,
 850                                      oap_pending_item) {
 851                 list_del_init(&oap->oap_rpc_item);
 852                 list_del_init(&oap->oap_pending_item);
 853                 if (last_off <= oap->oap_obj_off) {
 854                         last_off = oap->oap_obj_off;
 855                         last_count = oap->oap_count;
 856                 }
 857
 858                 --ext->oe_nr_pages;
 859                 osc_ap_completion(env, cli, oap, sent, rc);
 860         }
 861         EASSERT(ext->oe_nr_pages == 0, ext);
 862
 863         if (!sent) {
 864                 lost_grant = ext->oe_grants;
 865         } else if (cli->cl_ocd_grant_param == 0 &&
 866                    blocksize < PAGE_SIZE &&
 867                    last_count != PAGE_SIZE) {
 868                 /* For short writes without OBD_CONNECT_GRANT support, we
 869                  * shouldn't count parts of pages that span a whole chunk on
 870                  * the OST side, or our accounting goes wrong. Should match
 871                  * the code in tgt_grant_check.
 872                  */
 873                 int offset = last_off & ~PAGE_MASK;
 874                 int count = last_count + (offset & (blocksize - 1));
 875                 int end = (offset + last_count) & (blocksize - 1);
 876                 if (end)
 877                         count += blocksize - end;
 878
 879                 lost_grant = PAGE_SIZE - count;
 880         }
 881         if (ext->oe_grants > 0)
 882                 osc_free_grant(cli, nr_pages, lost_grant, ext->oe_grants);
 883
 884         osc_extent_remove(ext);
 885         /* put the refcount for RPC */
 886         osc_extent_put(env, ext);
 887         RETURN(0);
 888 }
 889
 890 /**
 891  * Wait for the extent's state to become @state.
 892  */
 893 static int osc_extent_wait(const struct lu_env *env, struct osc_extent *ext,
 894                            enum osc_extent_state state)
 895 {
 896         struct osc_object *obj = ext->oe_obj;
 897         int rc = 0;
 898         ENTRY;
 899
 900         osc_object_lock(obj);
 901         LASSERT(sanity_check_nolock(ext) == 0);
 902         /* `Kick' this extent only if the caller is waiting for it to be
 903          * written out. */
 904         if (state == OES_INV && !ext->oe_urgent && !ext->oe_hp) {
 905                 if (ext->oe_state == OES_ACTIVE) {
 906                         ext->oe_urgent = 1;
 907                 } else if (ext->oe_state == OES_CACHE) {
 908                         ext->oe_urgent = 1;
 909                         osc_extent_hold(ext);
 910                         rc = 1;
 911                 }
 912         }
 913         osc_object_unlock(obj);
 914         if (rc == 1)
 915                 osc_extent_release(env, ext);
 916
 917         /* wait for the extent until its state becomes @state */
 918         rc = wait_event_idle_timeout(ext->oe_waitq,
 919                                      smp_load_acquire(&ext->oe_state) == state,
 920                                      cfs_time_seconds(600));
 921         if (rc == 0) {
 922                 OSC_EXTENT_DUMP(D_ERROR, ext,
 923                         "%s: wait ext to %u timedout, recovery in progress?\n",
 924                         cli_name(osc_cli(obj)), state);
 925
 926                 wait_event_idle(ext->oe_waitq,
 927                                 smp_load_acquire(&ext->oe_state) == state);
 928         }
 929         if (ext->oe_rc < 0)
 930                 rc = ext->oe_rc;
 931         else
 932                 rc = 0;
 933         RETURN(rc);
 934 }
 935
 936 /**
 937  * Discard pages with index greater than @size. If @ext is overlapped with
 938  * @size, then partial truncate happens.
 939  */
 940 static int osc_extent_truncate(struct osc_extent *ext, pgoff_t trunc_index,
 941                                 bool partial)
 942 {
 943         struct lu_env         *env;
 944         struct cl_io          *io;
 945         struct osc_object     *obj = ext->oe_obj;
 946         struct client_obd     *cli = osc_cli(obj);
 947         struct osc_async_page *oap;
 948         struct osc_async_page *tmp;
 949         struct pagevec        *pvec;
 950         int                    pages_in_chunk = 0;
 951         int                    ppc_bits    = cli->cl_chunkbits -
 952                                              PAGE_SHIFT;
 953         __u64                  trunc_chunk = trunc_index >> ppc_bits;
 954         int                    grants   = 0;
 955         int                    nr_pages = 0;
 956         int                    rc       = 0;
 957         __u16                  refcheck;
 958         ENTRY;
 959
 960         LASSERT(sanity_check(ext) == 0);
 961         LASSERT(ext->oe_state == OES_TRUNC);
 962         LASSERT(!ext->oe_urgent);
 963
 964         /* Request new lu_env.
 965          * We can't use that env from osc_cache_truncate_start() because
 966          * it's from lov_io_sub and not fully initialized. */
 967         env = cl_env_get(&refcheck);
 968         if (IS_ERR(env))
 969                 RETURN(PTR_ERR(env));
 970
 971         io  = osc_env_thread_io(env);
 972         io->ci_obj = cl_object_top(osc2cl(obj));
 973         io->ci_ignore_layout = 1;
 974         pvec = &osc_env_info(env)->oti_pagevec;
 975         ll_pagevec_init(pvec, 0);
 976         rc = cl_io_init(env, io, CIT_MISC, io->ci_obj);
 977         if (rc < 0)
 978                 GOTO(out, rc);
 979
 980         /* discard all pages with index greater than trunc_index */
 981         list_for_each_entry_safe(oap, tmp, &ext->oe_pages,
 982                                      oap_pending_item) {
 983                 pgoff_t index = osc_index(oap2osc(oap));
 984                 struct cl_page  *page = oap2cl_page(oap);
 985
 986                 LASSERT(list_empty(&oap->oap_rpc_item));
 987
 988                 /* only discard the pages with their index greater than
 989                  * trunc_index, and ... */
 990                 if (index < trunc_index ||
 991                     (index == trunc_index && partial)) {
 992                         /* accounting how many pages remaining in the chunk
 993                          * so that we can calculate grants correctly. */
 994                         if (index >> ppc_bits == trunc_chunk)
 995                                 ++pages_in_chunk;
 996                         continue;
 997                 }
 998
 999                 list_del_init(&oap->oap_pending_item);
1000
1001                 cl_page_get(page);
1002                 lu_ref_add(&page->cp_reference, "truncate", current);
1003
1004                 if (cl_page_own(env, io, page) == 0) {
1005                         cl_page_discard(env, io, page);
1006                         cl_page_disown(env, io, page);
1007                 } else {
1008                         LASSERT(page->cp_state == CPS_FREEING);
1009                         LASSERT(0);
1010                 }
1011
1012                 lu_ref_del(&page->cp_reference, "truncate", current);
1013                 cl_pagevec_put(env, page, pvec);
1014
1015                 --ext->oe_nr_pages;
1016                 ++nr_pages;
1017         }
1018         pagevec_release(pvec);
1019
1020         EASSERTF(ergo(ext->oe_start >= trunc_index + !!partial,
1021                       ext->oe_nr_pages == 0),
1022                 ext, "trunc_index %lu, partial %d\n", trunc_index, partial);
1023
1024         osc_object_lock(obj);
1025         if (ext->oe_nr_pages == 0) {
1026                 LASSERT(pages_in_chunk == 0);
1027                 grants = ext->oe_grants;
1028                 ext->oe_grants = 0;
1029         } else { /* calculate how many grants we can free */
1030                 int     chunks = (ext->oe_end >> ppc_bits) - trunc_chunk;
1031                 pgoff_t last_index;
1032
1033
1034                 /* if there is no pages in this chunk, we can also free grants
1035                  * for the last chunk */
1036                 if (pages_in_chunk == 0) {
1037                         /* if this is the 1st chunk and no pages in this chunk,
1038                          * ext->oe_nr_pages must be zero, so we should be in
1039                          * the other if-clause. */
1040                         LASSERT(trunc_chunk > 0);
1041                         --trunc_chunk;
1042                         ++chunks;
1043                 }
1044
1045                 /* this is what we can free from this extent */
1046                 grants          = chunks << cli->cl_chunkbits;
1047                 ext->oe_grants -= grants;
1048                 last_index      = ((trunc_chunk + 1) << ppc_bits) - 1;
1049                 ext->oe_end     = min(last_index, ext->oe_max_end);
1050                 LASSERT(ext->oe_end >= ext->oe_start);
1051                 LASSERT(ext->oe_grants > 0);
1052         }
1053         osc_object_unlock(obj);
1054
1055         if (grants > 0 || nr_pages > 0)
1056                 osc_free_grant(cli, nr_pages, grants, grants);
1057
1058 out:
1059         cl_io_fini(env, io);
1060         cl_env_put(env, &refcheck);
1061         RETURN(rc);
1062 }
1063
1064 /**
1065  * This function is used to make the extent prepared for transfer.
1066  * A race with flusing page - ll_writepage() has to be handled cautiously.
1067  */
1068 static int osc_extent_make_ready(const struct lu_env *env,
1069                                  struct osc_extent *ext)
1070 {
1071         struct osc_async_page *oap;
1072         struct osc_async_page *last = NULL;
1073         struct osc_object *obj = ext->oe_obj;
1074         unsigned int page_count = 0;
1075         int rc;
1076         ENTRY;
1077
1078         /* we're going to grab page lock, so object lock must not be taken. */
1079         LASSERT(sanity_check(ext) == 0);
1080         /* in locking state, any process should not touch this extent. */
1081         EASSERT(ext->oe_state == OES_LOCKING, ext);
1082         EASSERT(ext->oe_owner != NULL, ext);
1083
1084         OSC_EXTENT_DUMP(D_CACHE, ext, "make ready\n");
1085
1086         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
1087                 ++page_count;
1088                 if (last == NULL || last->oap_obj_off < oap->oap_obj_off)
1089                         last = oap;
1090
1091                 /* checking ASYNC_READY is race safe */
1092                 if ((oap->oap_async_flags & ASYNC_READY) != 0)
1093                         continue;
1094
1095                 rc = osc_make_ready(env, oap, OBD_BRW_WRITE);
1096                 switch (rc) {
1097                 case 0:
1098                         oap->oap_async_flags |= ASYNC_READY;
1099                         break;
1100                 case -EALREADY:
1101                         LASSERT((oap->oap_async_flags & ASYNC_READY) != 0);
1102                         break;
1103                 default:
1104                         LASSERTF(0, "unknown return code: %d\n", rc);
1105                 }
1106         }
1107
1108         LASSERT(page_count == ext->oe_nr_pages);
1109         LASSERT(last != NULL);
1110         /* the last page is the only one we need to refresh its count by
1111          * the size of file. */
1112         if (!(last->oap_async_flags & ASYNC_COUNT_STABLE)) {
1113                 int last_oap_count = osc_refresh_count(env, last, OBD_BRW_WRITE);
1114                 LASSERTF(last_oap_count > 0,
1115                          "last_oap_count %d\n", last_oap_count);
1116                 LASSERT(last->oap_page_off + last_oap_count <= PAGE_SIZE);
1117                 last->oap_count = last_oap_count;
1118                 last->oap_async_flags |= ASYNC_COUNT_STABLE;
1119         }
1120
1121         /* for the rest of pages, we don't need to call osf_refresh_count()
1122          * because it's known they are not the last page */
1123         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
1124                 if (!(oap->oap_async_flags & ASYNC_COUNT_STABLE)) {
1125                         oap->oap_count = PAGE_SIZE - oap->oap_page_off;
1126                         oap->oap_async_flags |= ASYNC_COUNT_STABLE;
1127                 }
1128         }
1129
1130         osc_object_lock(obj);
1131         osc_extent_state_set(ext, OES_RPC);
1132         osc_object_unlock(obj);
1133         /* get a refcount for RPC. */
1134         osc_extent_get(ext);
1135
1136         RETURN(0);
1137 }
1138
1139 /**
1140  * Quick and simple version of osc_extent_find(). This function is frequently
1141  * called to expand the extent for the same IO. To expand the extent, the
1142  * page index must be in the same or next chunk of ext->oe_end.
1143  */
1144 static int osc_extent_expand(struct osc_extent *ext, pgoff_t index,
1145                              unsigned int *grants)
1146 {
1147         struct osc_object *obj = ext->oe_obj;
1148         struct client_obd *cli = osc_cli(obj);
1149         struct osc_extent *next;
1150         int ppc_bits = cli->cl_chunkbits - PAGE_SHIFT;
1151         pgoff_t chunk = index >> ppc_bits;
1152         pgoff_t end_chunk;
1153         pgoff_t end_index;
1154         unsigned int chunksize = 1 << cli->cl_chunkbits;
1155         int rc = 0;
1156         ENTRY;
1157
1158         LASSERT(ext->oe_max_end >= index && ext->oe_start <= index);
1159         osc_object_lock(obj);
1160         LASSERT(sanity_check_nolock(ext) == 0);
1161         end_chunk = ext->oe_end >> ppc_bits;
1162         if (chunk > end_chunk + 1)
1163                 GOTO(out, rc = -ERANGE);
1164
1165         if (end_chunk >= chunk)
1166                 GOTO(out, rc = 0);
1167
1168         LASSERT(end_chunk + 1 == chunk);
1169
1170         /* try to expand this extent to cover @index */
1171         end_index = min(ext->oe_max_end, ((chunk + 1) << ppc_bits) - 1);
1172
1173         /* don't go over the maximum extent size reported by server */
1174         if (end_index - ext->oe_start + 1 > cli->cl_max_extent_pages)
1175                 GOTO(out, rc = -ERANGE);
1176
1177         next = next_extent(ext);
1178         if (next != NULL && next->oe_start <= end_index)
1179                 /* complex mode - overlapped with the next extent,
1180                  * this case will be handled by osc_extent_find() */
1181                 GOTO(out, rc = -EAGAIN);
1182
1183         ext->oe_end = end_index;
1184         ext->oe_grants += chunksize;
1185         LASSERT(*grants >= chunksize);
1186         *grants -= chunksize;
1187         EASSERTF(osc_extent_is_overlapped(obj, ext) == 0, ext,
1188                  "overlapped after expanding for %lu.\n", index);
1189         EXIT;
1190
1191 out:
1192         osc_object_unlock(obj);
1193         RETURN(rc);
1194 }
1195
1196 static void osc_extent_tree_dump0(int mask, struct osc_object *obj,
1197                                   const char *func, int line)
1198 {
1199         struct osc_extent *ext;
1200         int cnt;
1201
1202         if (!cfs_cdebug_show(mask, DEBUG_SUBSYSTEM))
1203                 return;
1204
1205         CDEBUG(mask, "Dump object %p extents at %s:%d, mppr: %u.\n",
1206                obj, func, line, osc_cli(obj)->cl_max_pages_per_rpc);
1207
1208         /* osc_object_lock(obj); */
1209         cnt = 1;
1210         for (ext = first_extent(obj); ext != NULL; ext = next_extent(ext))
1211                 OSC_EXTENT_DUMP(mask, ext, "in tree %d.\n", cnt++);
1212
1213         cnt = 1;
1214         list_for_each_entry(ext, &obj->oo_hp_exts, oe_link)
1215                 OSC_EXTENT_DUMP(mask, ext, "hp %d.\n", cnt++);
1216
1217         cnt = 1;
1218         list_for_each_entry(ext, &obj->oo_urgent_exts, oe_link)
1219                 OSC_EXTENT_DUMP(mask, ext, "urgent %d.\n", cnt++);
1220
1221         cnt = 1;
1222         list_for_each_entry(ext, &obj->oo_reading_exts, oe_link)
1223                 OSC_EXTENT_DUMP(mask, ext, "reading %d.\n", cnt++);
1224         /* osc_object_unlock(obj); */
1225 }
1226
1227 /* ------------------ osc extent end ------------------ */
1228
1229 static inline int osc_is_ready(struct osc_object *osc)
1230 {
1231         return !list_empty(&osc->oo_ready_item) ||
1232                !list_empty(&osc->oo_hp_ready_item);
1233 }
1234
1235 #define OSC_IO_DEBUG(OSC, STR, args...)                                        \
1236         CDEBUG(D_CACHE, "obj %p ready %d|%c|%c wr %d|%c|%c rd %d|%c " STR,     \
1237                (OSC), osc_is_ready(OSC),                                       \
1238                list_empty_marker(&(OSC)->oo_hp_ready_item),                    \
1239                list_empty_marker(&(OSC)->oo_ready_item),                       \
1240                atomic_read(&(OSC)->oo_nr_writes),                              \
1241                list_empty_marker(&(OSC)->oo_hp_exts),                          \
1242                list_empty_marker(&(OSC)->oo_urgent_exts),                      \
1243                atomic_read(&(OSC)->oo_nr_reads),                               \
1244                list_empty_marker(&(OSC)->oo_reading_exts),                     \
1245                ##args)
1246
1247 static int osc_make_ready(const struct lu_env *env, struct osc_async_page *oap,
1248                           int cmd)
1249 {
1250         struct cl_page  *page = oap2cl_page(oap);
1251         int result;
1252
1253         LASSERT(cmd == OBD_BRW_WRITE); /* no cached reads */
1254
1255         ENTRY;
1256
1257         result = cl_page_make_ready(env, page, CRT_WRITE);
1258
1259         RETURN(result);
1260 }
1261
1262 static int osc_refresh_count(const struct lu_env *env,
1263                              struct osc_async_page *oap, int cmd)
1264 {
1265         struct osc_page  *opg = oap2osc_page(oap);
1266         pgoff_t index = osc_index(oap2osc(oap));
1267         struct cl_object *obj = osc2cl(osc_page_object(opg));
1268         struct cl_attr   *attr = &osc_env_info(env)->oti_attr;
1269         int result;
1270         loff_t kms;
1271
1272         /* readpage queues with _COUNT_STABLE, shouldn't get here. */
1273         LASSERT(!(cmd & OBD_BRW_READ));
1274         LASSERT(opg != NULL);
1275
1276         cl_object_attr_lock(obj);
1277         result = cl_object_attr_get(env, obj, attr);
1278         cl_object_attr_unlock(obj);
1279         if (result < 0)
1280                 return result;
1281         kms = attr->cat_kms;
1282         if (index << PAGE_SHIFT >= kms)
1283                 /* catch race with truncate */
1284                 return 0;
1285         else if ((index + 1) << PAGE_SHIFT > kms)
1286                 /* catch sub-page write at end of file */
1287                 return kms & ~PAGE_MASK;
1288         else
1289                 return PAGE_SIZE;
1290 }
1291
1292 static int osc_completion(const struct lu_env *env, struct osc_async_page *oap,
1293                           int cmd, int rc)
1294 {
1295         struct osc_page   *opg  = oap2osc_page(oap);
1296         struct cl_page    *page = oap2cl_page(oap);
1297         enum cl_req_type   crt;
1298         int srvlock;
1299
1300         ENTRY;
1301
1302         cmd &= ~OBD_BRW_NOQUOTA;
1303         LASSERTF(equi(page->cp_state == CPS_PAGEIN,  cmd == OBD_BRW_READ),
1304                  "cp_state:%u, cmd:%d\n", page->cp_state, cmd);
1305         LASSERTF(equi(page->cp_state == CPS_PAGEOUT, cmd == OBD_BRW_WRITE),
1306                 "cp_state:%u, cmd:%d\n", page->cp_state, cmd);
1307         LASSERT(opg->ops_transfer_pinned);
1308
1309         crt = cmd == OBD_BRW_READ ? CRT_READ : CRT_WRITE;
1310         /* Clear opg->ops_transfer_pinned before VM lock is released. */
1311         opg->ops_transfer_pinned = 0;
1312
1313         srvlock = oap->oap_brw_flags & OBD_BRW_SRVLOCK;
1314
1315         /* statistic */
1316         if (rc == 0 && srvlock) {
1317                 struct lu_device *ld = osc_page_object(opg)->oo_cl.co_lu.lo_dev;
1318                 struct osc_stats *stats = &lu2osc_dev(ld)->osc_stats;
1319                 size_t 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         cl_page_put(env, page);
1336
1337         RETURN(0);
1338 }
1339
1340 #define OSC_DUMP_GRANT(mask, cli, fmt, args...) do {                    \
1341         struct client_obd *__tmp = (cli);                               \
1342         CDEBUG(mask, "%s: grant { dirty: %ld/%ld dirty_pages: %ld/%lu " \
1343                "dropped: %ld avail: %ld, dirty_grant: %ld, "            \
1344                "reserved: %ld, flight: %d } lru {in list: %ld, "        \
1345                "left: %ld, waiters: %d }" fmt "\n",                     \
1346                cli_name(__tmp),                                         \
1347                __tmp->cl_dirty_pages, __tmp->cl_dirty_max_pages,        \
1348                atomic_long_read(&obd_dirty_pages), obd_max_dirty_pages, \
1349                __tmp->cl_lost_grant, __tmp->cl_avail_grant,             \
1350                __tmp->cl_dirty_grant,                                   \
1351                __tmp->cl_reserved_grant, __tmp->cl_w_in_flight,         \
1352                atomic_long_read(&__tmp->cl_lru_in_list),                \
1353                atomic_long_read(&__tmp->cl_lru_busy),                   \
1354                atomic_read(&__tmp->cl_lru_shrinkers), ##args);          \
1355 } while (0)
1356
1357 /* caller must hold loi_list_lock */
1358 static void osc_consume_write_grant(struct client_obd *cli,
1359                                     struct brw_page *pga)
1360 {
1361         assert_spin_locked(&cli->cl_loi_list_lock);
1362         LASSERT(!(pga->flag & OBD_BRW_FROM_GRANT));
1363         cli->cl_dirty_pages++;
1364         pga->flag |= OBD_BRW_FROM_GRANT;
1365         CDEBUG(D_CACHE, "using %lu grant credits for brw %p page %p\n",
1366                PAGE_SIZE, pga, pga->pg);
1367 }
1368
1369 /* the companion to osc_consume_write_grant, called when a brw has completed.
1370  * must be called with the loi lock held. */
1371 static void osc_release_write_grant(struct client_obd *cli,
1372                                     struct brw_page *pga)
1373 {
1374         ENTRY;
1375
1376         assert_spin_locked(&cli->cl_loi_list_lock);
1377         if (!(pga->flag & OBD_BRW_FROM_GRANT)) {
1378                 EXIT;
1379                 return;
1380         }
1381
1382         pga->flag &= ~OBD_BRW_FROM_GRANT;
1383         atomic_long_dec(&obd_dirty_pages);
1384         cli->cl_dirty_pages--;
1385         EXIT;
1386 }
1387
1388 /**
1389  * To avoid sleeping with object lock held, it's good for us allocate enough
1390  * grants before entering into critical section.
1391  *
1392  * client_obd_list_lock held by caller
1393  */
1394 static int osc_reserve_grant(struct client_obd *cli, unsigned int bytes)
1395 {
1396         int rc = -EDQUOT;
1397
1398         if (cli->cl_avail_grant >= bytes) {
1399                 cli->cl_avail_grant    -= bytes;
1400                 cli->cl_reserved_grant += bytes;
1401                 rc = 0;
1402         }
1403         return rc;
1404 }
1405
1406 static void __osc_unreserve_grant(struct client_obd *cli,
1407                                   unsigned int reserved, unsigned int unused)
1408 {
1409         /* it's quite normal for us to get more grant than reserved.
1410          * Thinking about a case that two extents merged by adding a new
1411          * chunk, we can save one extent tax. If extent tax is greater than
1412          * one chunk, we can save more grant by adding a new chunk */
1413         cli->cl_reserved_grant -= reserved;
1414         if (unused > reserved) {
1415                 cli->cl_avail_grant += reserved;
1416                 cli->cl_lost_grant  += unused - reserved;
1417                 cli->cl_dirty_grant -= unused - reserved;
1418         } else {
1419                 cli->cl_avail_grant += unused;
1420                 cli->cl_dirty_grant += reserved - unused;
1421         }
1422 }
1423
1424 static void osc_unreserve_grant_nolock(struct client_obd *cli,
1425                                        unsigned int reserved,
1426                                        unsigned int unused)
1427 {
1428         __osc_unreserve_grant(cli, reserved, unused);
1429         if (unused > 0)
1430                 osc_wake_cache_waiters(cli);
1431 }
1432
1433 static void osc_unreserve_grant(struct client_obd *cli,
1434                                 unsigned int reserved, unsigned int unused)
1435 {
1436         spin_lock(&cli->cl_loi_list_lock);
1437         osc_unreserve_grant_nolock(cli, reserved, unused);
1438         spin_unlock(&cli->cl_loi_list_lock);
1439 }
1440
1441 /**
1442  * Free grant after IO is finished or canceled.
1443  *
1444  * @lost_grant is used to remember how many grants we have allocated but not
1445  * used, we should return these grants to OST. There're two cases where grants
1446  * can be lost:
1447  * 1. truncate;
1448  * 2. Without OBD_CONNECT_GRANT support and blocksize at OST is less than
1449  *    PAGE_SIZE and a partial page was written. In this case OST may use less
1450  *    chunks to serve this partial write. OSTs don't actually know the page
1451  *    size on the client side. so clients have to calculate lost grant by the
1452  *    blocksize on the OST. See tgt_grant_check() for details.
1453  */
1454 static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
1455                            unsigned int lost_grant, unsigned int dirty_grant)
1456 {
1457         unsigned long grant;
1458
1459         grant = (1 << cli->cl_chunkbits) + cli->cl_grant_extent_tax;
1460
1461         spin_lock(&cli->cl_loi_list_lock);
1462         atomic_long_sub(nr_pages, &obd_dirty_pages);
1463         cli->cl_dirty_pages -= nr_pages;
1464         cli->cl_lost_grant += lost_grant;
1465         cli->cl_dirty_grant -= dirty_grant;
1466         if (cli->cl_avail_grant < grant && cli->cl_lost_grant >= grant) {
1467                 /* borrow some grant from truncate to avoid the case that
1468                  * truncate uses up all avail grant */
1469                 cli->cl_lost_grant -= grant;
1470                 cli->cl_avail_grant += grant;
1471         }
1472         osc_wake_cache_waiters(cli);
1473         spin_unlock(&cli->cl_loi_list_lock);
1474         CDEBUG(D_CACHE, "lost %u grant: %lu avail: %lu dirty: %lu/%lu\n",
1475                lost_grant, cli->cl_lost_grant,
1476                cli->cl_avail_grant, cli->cl_dirty_pages << PAGE_SHIFT,
1477                cli->cl_dirty_grant);
1478 }
1479
1480 /**
1481  * The companion to osc_enter_cache(), called when @oap is no longer part of
1482  * the dirty accounting due to error.
1483  */
1484 static void osc_exit_cache(struct client_obd *cli, struct osc_async_page *oap)
1485 {
1486         spin_lock(&cli->cl_loi_list_lock);
1487         osc_release_write_grant(cli, &oap->oap_brw_page);
1488         spin_unlock(&cli->cl_loi_list_lock);
1489 }
1490
1491 /**
1492  * Non-blocking version of osc_enter_cache() that consumes grant only when it
1493  * is available.
1494  */
1495 static int osc_enter_cache_try(struct client_obd *cli,
1496                                struct osc_async_page *oap,
1497                                int bytes)
1498 {
1499         int rc;
1500
1501         OSC_DUMP_GRANT(D_CACHE, cli, "need:%d\n", bytes);
1502
1503         rc = osc_reserve_grant(cli, bytes);
1504         if (rc < 0)
1505                 return 0;
1506
1507         if (cli->cl_dirty_pages < cli->cl_dirty_max_pages) {
1508                 if (atomic_long_add_return(1, &obd_dirty_pages) <=
1509                     obd_max_dirty_pages) {
1510                         osc_consume_write_grant(cli, &oap->oap_brw_page);
1511                         rc = 1;
1512                         goto out;
1513                 } else
1514                         atomic_long_dec(&obd_dirty_pages);
1515         }
1516         __osc_unreserve_grant(cli, bytes, bytes);
1517
1518 out:
1519         return rc;
1520 }
1521
1522 /* Following two inlines exist to pass code fragments
1523  * to wait_event_idle_exclusive_timeout_cmd().  Passing
1524  * code fragments as macro args can look confusing, so
1525  * we provide inlines to encapsulate them.
1526  */
1527 static inline void cli_unlock_and_unplug(const struct lu_env *env,
1528                                          struct client_obd *cli,
1529                                          struct osc_async_page *oap)
1530 {
1531         spin_unlock(&cli->cl_loi_list_lock);
1532         osc_io_unplug_async(env, cli, NULL);
1533         CDEBUG(D_CACHE,
1534                "%s: sleeping for cache space for %p\n",
1535                cli_name(cli), oap);
1536 }
1537
1538 static inline void cli_lock_after_unplug(struct client_obd *cli)
1539 {
1540         spin_lock(&cli->cl_loi_list_lock);
1541 }
1542 /**
1543  * The main entry to reserve dirty page accounting. Usually the grant reserved
1544  * in this function will be freed in bulk in osc_free_grant() unless it fails
1545  * to add osc cache, in that case, it will be freed in osc_exit_cache().
1546  *
1547  * The process will be put into sleep if it's already run out of grant.
1548  */
1549 static int osc_enter_cache(const struct lu_env *env, struct client_obd *cli,
1550                            struct osc_async_page *oap, int bytes)
1551 {
1552         struct osc_object *osc = oap->oap_obj;
1553         struct lov_oinfo *loi = osc->oo_oinfo;
1554         int rc = -EDQUOT;
1555         int remain;
1556         bool entered = false;
1557         /* We cannot wait for a long time here since we are holding ldlm lock
1558          * across the actual IO. If no requests complete fast (e.g. due to
1559          * overloaded OST that takes a long time to process everything, we'd
1560          * get evicted if we wait for a normal obd_timeout or some such.
1561          * So we try to wait half the time it would take the client to be
1562          * evicted by server which is half obd_timeout when AT is off
1563          * or at least ldlm_enqueue_min with AT on.
1564          * See LU-13131 */
1565         unsigned long timeout = cfs_time_seconds(AT_OFF ? obd_timeout / 2 :
1566                                                           ldlm_enqueue_min / 2);
1567
1568         ENTRY;
1569
1570         OSC_DUMP_GRANT(D_CACHE, cli, "need:%d\n", bytes);
1571
1572         spin_lock(&cli->cl_loi_list_lock);
1573
1574         /* force the caller to try sync io.  this can jump the list
1575          * of queued writes and create a discontiguous rpc stream */
1576         if (CFS_FAIL_CHECK(OBD_FAIL_OSC_NO_GRANT) ||
1577             cli->cl_dirty_max_pages == 0 ||
1578             cli->cl_ar.ar_force_sync || loi->loi_ar.ar_force_sync) {
1579                 OSC_DUMP_GRANT(D_CACHE, cli, "forced sync i/o\n");
1580                 GOTO(out, rc = -EDQUOT);
1581         }
1582
1583         /*
1584          * We can wait here for two reasons: too many dirty pages in cache, or
1585          * run out of grants. In both cases we should write dirty pages out.
1586          * Adding a cache waiter will trigger urgent write-out no matter what
1587          * RPC size will be.
1588          * The exiting condition (other than success) is no avail grants
1589          * and no dirty pages caching, that really means there is no space
1590          * on the OST.
1591          */
1592         remain = wait_event_idle_exclusive_timeout_cmd(
1593                 cli->cl_cache_waiters,
1594                 (entered = osc_enter_cache_try(cli, oap, bytes)) ||
1595                 (cli->cl_dirty_pages == 0 && cli->cl_w_in_flight == 0),
1596                 timeout,
1597                 cli_unlock_and_unplug(env, cli, oap),
1598                 cli_lock_after_unplug(cli));
1599
1600         if (entered) {
1601                 if (remain == timeout)
1602                         OSC_DUMP_GRANT(D_CACHE, cli, "granted from cache\n");
1603                 else
1604                         OSC_DUMP_GRANT(D_CACHE, cli,
1605                                        "finally got grant space\n");
1606                 wake_up(&cli->cl_cache_waiters);
1607                 rc = 0;
1608         } else if (remain == 0) {
1609                 OSC_DUMP_GRANT(D_CACHE, cli,
1610                                "timeout, fall back to sync i/o\n");
1611                 osc_extent_tree_dump(D_CACHE, osc);
1612                 /* fall back to synchronous I/O */
1613         } else {
1614                 OSC_DUMP_GRANT(D_CACHE, cli,
1615                                "no grant space, fall back to sync i/o\n");
1616                 wake_up_all(&cli->cl_cache_waiters);
1617         }
1618         EXIT;
1619 out:
1620         spin_unlock(&cli->cl_loi_list_lock);
1621         RETURN(rc);
1622 }
1623
1624 static int osc_max_rpc_in_flight(struct client_obd *cli, struct osc_object *osc)
1625 {
1626         int hprpc = !!list_empty(&osc->oo_hp_exts);
1627         return rpcs_in_flight(cli) >= cli->cl_max_rpcs_in_flight + hprpc;
1628 }
1629
1630 /* This maintains the lists of pending pages to read/write for a given object
1631  * (lop).  This is used by osc_check_rpcs->osc_next_obj() and osc_list_maint()
1632  * to quickly find objects that are ready to send an RPC. */
1633 static int osc_makes_rpc(struct client_obd *cli, struct osc_object *osc,
1634                          int cmd)
1635 {
1636         int invalid_import = 0;
1637         ENTRY;
1638
1639         /* if we have an invalid import we want to drain the queued pages
1640          * by forcing them through rpcs that immediately fail and complete
1641          * the pages.  recovery relies on this to empty the queued pages
1642          * before canceling the locks and evicting down the llite pages */
1643         if ((cli->cl_import == NULL || cli->cl_import->imp_invalid))
1644                 invalid_import = 1;
1645
1646         if (cmd & OBD_BRW_WRITE) {
1647                 if (atomic_read(&osc->oo_nr_writes) == 0)
1648                         RETURN(0);
1649                 if (invalid_import) {
1650                         CDEBUG(D_CACHE, "invalid import forcing RPC\n");
1651                         RETURN(1);
1652                 }
1653                 if (!list_empty(&osc->oo_hp_exts)) {
1654                         CDEBUG(D_CACHE, "high prio request forcing RPC\n");
1655                         RETURN(1);
1656                 }
1657                 if (!list_empty(&osc->oo_urgent_exts)) {
1658                         CDEBUG(D_CACHE, "urgent request forcing RPC\n");
1659                         RETURN(1);
1660                 }
1661                 /* trigger a write rpc stream as long as there are dirtiers
1662                  * waiting for space.  as they're waiting, they're not going to
1663                  * create more pages to coalesce with what's waiting..
1664                  */
1665                 if (waitqueue_active(&cli->cl_cache_waiters)) {
1666                         CDEBUG(D_CACHE, "cache waiters forcing RPC\n");
1667                         RETURN(1);
1668                 }
1669                 if (!list_empty(&osc->oo_full_exts)) {
1670                         CDEBUG(D_CACHE, "full extent ready, make an RPC\n");
1671                         RETURN(1);
1672                 }
1673         } else {
1674                 if (atomic_read(&osc->oo_nr_reads) == 0)
1675                         RETURN(0);
1676                 if (invalid_import) {
1677                         CDEBUG(D_CACHE, "invalid import forcing RPC\n");
1678                         RETURN(1);
1679                 }
1680                 /* all read are urgent. */
1681                 if (!list_empty(&osc->oo_reading_exts))
1682                         RETURN(1);
1683         }
1684
1685         RETURN(0);
1686 }
1687
1688 static void osc_update_pending(struct osc_object *obj, int cmd, int delta)
1689 {
1690         struct client_obd *cli = osc_cli(obj);
1691         if (cmd & OBD_BRW_WRITE) {
1692                 atomic_add(delta, &obj->oo_nr_writes);
1693                 atomic_add(delta, &cli->cl_pending_w_pages);
1694                 LASSERT(atomic_read(&obj->oo_nr_writes) >= 0);
1695         } else {
1696                 atomic_add(delta, &obj->oo_nr_reads);
1697                 atomic_add(delta, &cli->cl_pending_r_pages);
1698                 LASSERT(atomic_read(&obj->oo_nr_reads) >= 0);
1699         }
1700         OSC_IO_DEBUG(obj, "update pending cmd %d delta %d.\n", cmd, delta);
1701 }
1702
1703 static int osc_makes_hprpc(struct osc_object *obj)
1704 {
1705         return !list_empty(&obj->oo_hp_exts);
1706 }
1707
1708 static void on_list(struct list_head *item, struct list_head *list,
1709                     int should_be_on)
1710 {
1711         if (list_empty(item) && should_be_on)
1712                 list_add_tail(item, list);
1713         else if (!list_empty(item) && !should_be_on)
1714                 list_del_init(item);
1715 }
1716
1717 /* maintain the osc's cli list membership invariants so that osc_send_oap_rpc
1718  * can find pages to build into rpcs quickly */
1719 static int __osc_list_maint(struct client_obd *cli, struct osc_object *osc)
1720 {
1721         if (osc_makes_hprpc(osc)) {
1722                 /* HP rpc */
1723                 on_list(&osc->oo_ready_item, &cli->cl_loi_ready_list, 0);
1724                 on_list(&osc->oo_hp_ready_item, &cli->cl_loi_hp_ready_list, 1);
1725         } else {
1726                 on_list(&osc->oo_hp_ready_item, &cli->cl_loi_hp_ready_list, 0);
1727                 on_list(&osc->oo_ready_item, &cli->cl_loi_ready_list,
1728                         osc_makes_rpc(cli, osc, OBD_BRW_WRITE) ||
1729                         osc_makes_rpc(cli, osc, OBD_BRW_READ));
1730         }
1731
1732         on_list(&osc->oo_write_item, &cli->cl_loi_write_list,
1733                 atomic_read(&osc->oo_nr_writes) > 0);
1734
1735         on_list(&osc->oo_read_item, &cli->cl_loi_read_list,
1736                 atomic_read(&osc->oo_nr_reads) > 0);
1737
1738         return osc_is_ready(osc);
1739 }
1740
1741 static int osc_list_maint(struct client_obd *cli, struct osc_object *osc)
1742 {
1743         int is_ready;
1744
1745         spin_lock(&cli->cl_loi_list_lock);
1746         is_ready = __osc_list_maint(cli, osc);
1747         spin_unlock(&cli->cl_loi_list_lock);
1748
1749         return is_ready;
1750 }
1751
1752 /* this is trying to propogate async writeback errors back up to the
1753  * application.  As an async write fails we record the error code for later if
1754  * the app does an fsync.  As long as errors persist we force future rpcs to be
1755  * sync so that the app can get a sync error and break the cycle of queueing
1756  * pages for which writeback will fail. */
1757 static void osc_process_ar(struct osc_async_rc *ar, __u64 xid,
1758                            int rc)
1759 {
1760         if (rc) {
1761                 if (!ar->ar_rc)
1762                         ar->ar_rc = rc;
1763
1764                 ar->ar_force_sync = 1;
1765                 ar->ar_min_xid = ptlrpc_sample_next_xid();
1766                 return;
1767
1768         }
1769
1770         if (ar->ar_force_sync && (xid >= ar->ar_min_xid))
1771                 ar->ar_force_sync = 0;
1772 }
1773
1774 /* this must be called holding the loi list lock to give coverage to exit_cache,
1775  * async_flag maintenance, and oap_request */
1776 static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
1777                               struct osc_async_page *oap, int sent, int rc)
1778 {
1779         struct osc_object *osc = oap->oap_obj;
1780         struct lov_oinfo  *loi = osc->oo_oinfo;
1781         __u64 xid = 0;
1782
1783         ENTRY;
1784         if (oap->oap_request != NULL) {
1785                 xid = ptlrpc_req_xid(oap->oap_request);
1786                 ptlrpc_req_finished(oap->oap_request);
1787                 oap->oap_request = NULL;
1788         }
1789
1790         /* As the transfer for this page is being done, clear the flags */
1791         oap->oap_async_flags = 0;
1792
1793         if (oap->oap_cmd & OBD_BRW_WRITE && xid > 0) {
1794                 spin_lock(&cli->cl_loi_list_lock);
1795                 osc_process_ar(&cli->cl_ar, xid, rc);
1796                 osc_process_ar(&loi->loi_ar, xid, rc);
1797                 spin_unlock(&cli->cl_loi_list_lock);
1798         }
1799
1800         rc = osc_completion(env, oap, oap->oap_cmd, rc);
1801         if (rc)
1802                 CERROR("completion on oap %p obj %p returns %d.\n",
1803                        oap, osc, rc);
1804
1805         EXIT;
1806 }
1807
1808 struct extent_rpc_data {
1809         struct list_head        *erd_rpc_list;
1810         unsigned int            erd_page_count;
1811         unsigned int            erd_max_pages;
1812         unsigned int            erd_max_chunks;
1813         unsigned int            erd_max_extents;
1814 };
1815
1816 static inline unsigned osc_extent_chunks(const struct osc_extent *ext)
1817 {
1818         struct client_obd *cli = osc_cli(ext->oe_obj);
1819         unsigned ppc_bits = cli->cl_chunkbits - PAGE_SHIFT;
1820
1821         return (ext->oe_end >> ppc_bits) - (ext->oe_start >> ppc_bits) + 1;
1822 }
1823
1824 static inline bool
1825 can_merge(const struct osc_extent *ext, const struct osc_extent *in_rpc)
1826 {
1827         if (ext->oe_no_merge || in_rpc->oe_no_merge)
1828                 return false;
1829
1830         if (ext->oe_srvlock != in_rpc->oe_srvlock)
1831                 return false;
1832
1833         if (ext->oe_ndelay != in_rpc->oe_ndelay)
1834                 return false;
1835
1836         if (!ext->oe_grants != !in_rpc->oe_grants)
1837                 return false;
1838
1839         if (ext->oe_dio != in_rpc->oe_dio)
1840                 return false;
1841
1842         /* It's possible to have overlap on DIO */
1843         if (in_rpc->oe_dio && overlapped(ext, in_rpc))
1844                 return false;
1845
1846         if (ext->oe_is_rdma_only != in_rpc->oe_is_rdma_only)
1847                 return false;
1848
1849         return true;
1850 }
1851
1852 /**
1853  * Try to add extent to one RPC. We need to think about the following things:
1854  * - # of pages must not be over max_pages_per_rpc
1855  * - extent must be compatible with previous ones
1856  */
1857 static int try_to_add_extent_for_io(struct client_obd *cli,
1858                                     struct osc_extent *ext,
1859                                     struct extent_rpc_data *data)
1860 {
1861         struct osc_extent *tmp;
1862         unsigned int chunk_count;
1863         ENTRY;
1864
1865         EASSERT((ext->oe_state == OES_CACHE || ext->oe_state == OES_LOCK_DONE),
1866                 ext);
1867         OSC_EXTENT_DUMP(D_CACHE, ext, "trying to add this extent\n");
1868
1869         if (data->erd_max_extents == 0)
1870                 RETURN(0);
1871
1872         chunk_count = osc_extent_chunks(ext);
1873         EASSERTF(data->erd_page_count != 0 ||
1874                  chunk_count <= data->erd_max_chunks, ext,
1875                  "The first extent to be fit in a RPC contains %u chunks, "
1876                  "which is over the limit %u.\n", chunk_count,
1877                  data->erd_max_chunks);
1878         if (chunk_count > data->erd_max_chunks)
1879                 RETURN(0);
1880
1881         data->erd_max_pages = max(ext->oe_mppr, data->erd_max_pages);
1882         EASSERTF(data->erd_page_count != 0 ||
1883                 ext->oe_nr_pages <= data->erd_max_pages, ext,
1884                 "The first extent to be fit in a RPC contains %u pages, "
1885                 "which is over the limit %u.\n", ext->oe_nr_pages,
1886                 data->erd_max_pages);
1887         if (data->erd_page_count + ext->oe_nr_pages > data->erd_max_pages)
1888                 RETURN(0);
1889
1890         list_for_each_entry(tmp, data->erd_rpc_list, oe_link) {
1891                 EASSERT(tmp->oe_owner == current, tmp);
1892
1893                 if (!can_merge(ext, tmp))
1894                         RETURN(0);
1895         }
1896
1897         data->erd_max_extents--;
1898         data->erd_max_chunks -= chunk_count;
1899         data->erd_page_count += ext->oe_nr_pages;
1900         list_move_tail(&ext->oe_link, data->erd_rpc_list);
1901         ext->oe_owner = current;
1902         RETURN(1);
1903 }
1904
1905 /**
1906  * In order to prevent multiple ptlrpcd from breaking contiguous extents,
1907  * get_write_extent() takes all appropriate extents in atomic.
1908  *
1909  * The following policy is used to collect extents for IO:
1910  * 1. Add as many HP extents as possible;
1911  * 2. Add the first urgent extent in urgent extent list and take it out of
1912  *    urgent list;
1913  * 3. Add subsequent extents of this urgent extent;
1914  * 4. If urgent list is not empty, goto 2;
1915  * 5. Traverse the extent tree from the 1st extent;
1916  * 6. Above steps exit if there is no space in this RPC.
1917  */
1918 static unsigned int get_write_extents(struct osc_object *obj,
1919                                       struct list_head *rpclist)
1920 {
1921         struct client_obd *cli = osc_cli(obj);
1922         struct osc_extent *ext;
1923         struct extent_rpc_data data = {
1924                 .erd_rpc_list   = rpclist,
1925                 .erd_page_count = 0,
1926                 .erd_max_pages  = cli->cl_max_pages_per_rpc,
1927                 .erd_max_chunks = osc_max_write_chunks(cli),
1928                 .erd_max_extents = 256,
1929         };
1930
1931         assert_osc_object_is_locked(obj);
1932         while ((ext = list_first_entry_or_null(&obj->oo_hp_exts,
1933                                                struct osc_extent,
1934                                                oe_link)) != NULL) {
1935                 if (!try_to_add_extent_for_io(cli, ext, &data))
1936                         return data.erd_page_count;
1937                 EASSERT(ext->oe_nr_pages <= data.erd_max_pages, ext);
1938         }
1939         if (data.erd_page_count == data.erd_max_pages)
1940                 return data.erd_page_count;
1941
1942         while ((ext = list_first_entry_or_null(&obj->oo_urgent_exts,
1943                                                struct osc_extent,
1944                                                oe_link)) != NULL) {
1945                 if (!try_to_add_extent_for_io(cli, ext, &data))
1946                         return data.erd_page_count;
1947         }
1948         if (data.erd_page_count == data.erd_max_pages)
1949                 return data.erd_page_count;
1950
1951         /* One key difference between full extents and other extents: full
1952          * extents can usually only be added if the rpclist was empty, so if we
1953          * can't add one, we continue on to trying to add normal extents.  This
1954          * is so we don't miss adding extra extents to an RPC containing high
1955          * priority or urgent extents.
1956          */
1957         while ((ext = list_first_entry_or_null(&obj->oo_full_exts,
1958                                                struct osc_extent,
1959                                                oe_link)) != NULL) {
1960                 if (!try_to_add_extent_for_io(cli, ext, &data))
1961                         break;
1962         }
1963         if (data.erd_page_count == data.erd_max_pages)
1964                 return data.erd_page_count;
1965
1966         for (ext = first_extent(obj);
1967              ext;
1968              ext = next_extent(ext)) {
1969                 if ((ext->oe_state != OES_CACHE) ||
1970                     /* this extent may be already in current rpclist */
1971                     (!list_empty(&ext->oe_link) && ext->oe_owner))
1972                         continue;
1973
1974                 if (!try_to_add_extent_for_io(cli, ext, &data))
1975                         return data.erd_page_count;
1976         }
1977         return data.erd_page_count;
1978 }
1979
1980 static int
1981 osc_send_write_rpc(const struct lu_env *env, struct client_obd *cli,
1982                    struct osc_object *osc)
1983 __must_hold(osc)
1984 {
1985         LIST_HEAD(rpclist);
1986         struct osc_extent *ext;
1987         struct osc_extent *tmp;
1988         struct osc_extent *first = NULL;
1989         unsigned int page_count = 0;
1990         int srvlock = 0;
1991         int rc = 0;
1992         ENTRY;
1993
1994         assert_osc_object_is_locked(osc);
1995
1996         page_count = get_write_extents(osc, &rpclist);
1997         LASSERT(equi(page_count == 0, list_empty(&rpclist)));
1998
1999         if (list_empty(&rpclist))
2000                 RETURN(0);
2001
2002         osc_update_pending(osc, OBD_BRW_WRITE, -page_count);
2003
2004         list_for_each_entry(ext, &rpclist, oe_link) {
2005                 LASSERT(ext->oe_state == OES_CACHE ||
2006                         ext->oe_state == OES_LOCK_DONE);
2007                 if (ext->oe_state == OES_CACHE)
2008                         osc_extent_state_set(ext, OES_LOCKING);
2009                 else
2010                         osc_extent_state_set(ext, OES_RPC);
2011         }
2012
2013         /* we're going to grab page lock, so release object lock because
2014          * lock order is page lock -> object lock. */
2015         osc_object_unlock(osc);
2016
2017         list_for_each_entry_safe(ext, tmp, &rpclist, oe_link) {
2018                 if (ext->oe_state == OES_LOCKING) {
2019                         rc = osc_extent_make_ready(env, ext);
2020                         if (unlikely(rc < 0)) {
2021                                 list_del_init(&ext->oe_link);
2022                                 osc_extent_finish(env, ext, 0, rc);
2023                                 continue;
2024                         }
2025                 }
2026                 if (first == NULL) {
2027                         first = ext;
2028                         srvlock = ext->oe_srvlock;
2029                 } else {
2030                         LASSERT(srvlock == ext->oe_srvlock);
2031                 }
2032         }
2033
2034         if (!list_empty(&rpclist)) {
2035                 LASSERT(page_count > 0);
2036                 rc = osc_build_rpc(env, cli, &rpclist, OBD_BRW_WRITE);
2037                 LASSERT(list_empty(&rpclist));
2038         }
2039
2040         osc_object_lock(osc);
2041         RETURN(rc);
2042 }
2043
2044 /**
2045  * prepare pages for ASYNC io and put pages in send queue.
2046  *
2047  * \param cmd OBD_BRW_* macroses
2048  * \param lop pending pages
2049  *
2050  * \return zero if no page added to send queue.
2051  * \return 1 if pages successfully added to send queue.
2052  * \return negative on errors.
2053  */
2054 static int
2055 osc_send_read_rpc(const struct lu_env *env, struct client_obd *cli,
2056                   struct osc_object *osc)
2057 __must_hold(osc)
2058 {
2059         struct osc_extent *ext;
2060         struct osc_extent *next;
2061         LIST_HEAD(rpclist);
2062         struct extent_rpc_data data = {
2063                 .erd_rpc_list   = &rpclist,
2064                 .erd_page_count = 0,
2065                 .erd_max_pages  = cli->cl_max_pages_per_rpc,
2066                 .erd_max_chunks = UINT_MAX,
2067                 .erd_max_extents = UINT_MAX,
2068         };
2069         int rc = 0;
2070         ENTRY;
2071
2072         assert_osc_object_is_locked(osc);
2073         list_for_each_entry_safe(ext, next, &osc->oo_reading_exts, oe_link) {
2074                 EASSERT(ext->oe_state == OES_LOCK_DONE, ext);
2075                 if (!try_to_add_extent_for_io(cli, ext, &data))
2076                         break;
2077                 osc_extent_state_set(ext, OES_RPC);
2078                 EASSERT(ext->oe_nr_pages <= data.erd_max_pages, ext);
2079         }
2080         LASSERT(data.erd_page_count <= data.erd_max_pages);
2081
2082         osc_update_pending(osc, OBD_BRW_READ, -data.erd_page_count);
2083
2084         if (!list_empty(&rpclist)) {
2085                 osc_object_unlock(osc);
2086
2087                 rc = osc_build_rpc(env, cli, &rpclist, OBD_BRW_READ);
2088                 LASSERT(list_empty(&rpclist));
2089
2090                 osc_object_lock(osc);
2091         }
2092         RETURN(rc);
2093 }
2094
2095 #define list_to_obj(list, item) ({                                            \
2096         struct list_head *__tmp = (list)->next;                               \
2097         list_del_init(__tmp);                                         \
2098         list_entry(__tmp, struct osc_object, oo_##item);                      \
2099 })
2100
2101 /* This is called by osc_check_rpcs() to find which objects have pages that
2102  * we could be sending.  These lists are maintained by osc_makes_rpc(). */
2103 static struct osc_object *osc_next_obj(struct client_obd *cli)
2104 {
2105         ENTRY;
2106
2107         /* First return objects that have blocked locks so that they
2108          * will be flushed quickly and other clients can get the lock,
2109          * then objects which have pages ready to be stuffed into RPCs */
2110         if (!list_empty(&cli->cl_loi_hp_ready_list))
2111                 RETURN(list_to_obj(&cli->cl_loi_hp_ready_list, hp_ready_item));
2112         if (!list_empty(&cli->cl_loi_ready_list))
2113                 RETURN(list_to_obj(&cli->cl_loi_ready_list, ready_item));
2114
2115         /* then if we have cache waiters, return all objects with queued
2116          * writes.  This is especially important when many small files
2117          * have filled up the cache and not been fired into rpcs because
2118          * they don't pass the nr_pending/object threshhold
2119          */
2120         if (waitqueue_active(&cli->cl_cache_waiters) &&
2121             !list_empty(&cli->cl_loi_write_list))
2122                 RETURN(list_to_obj(&cli->cl_loi_write_list, write_item));
2123
2124         /* then return all queued objects when we have an invalid import
2125          * so that they get flushed */
2126         if (cli->cl_import == NULL || cli->cl_import->imp_invalid) {
2127                 if (!list_empty(&cli->cl_loi_write_list))
2128                         RETURN(list_to_obj(&cli->cl_loi_write_list,
2129                                            write_item));
2130                 if (!list_empty(&cli->cl_loi_read_list))
2131                         RETURN(list_to_obj(&cli->cl_loi_read_list,
2132                                            read_item));
2133         }
2134         RETURN(NULL);
2135 }
2136
2137 /* called with the loi list lock held */
2138 static void osc_check_rpcs(const struct lu_env *env, struct client_obd *cli)
2139 __must_hold(&cli->cl_loi_list_lock)
2140 {
2141         struct osc_object *osc;
2142         int rc = 0;
2143         ENTRY;
2144
2145         while ((osc = osc_next_obj(cli)) != NULL) {
2146                 struct cl_object *obj = osc2cl(osc);
2147                 struct lu_ref_link link;
2148
2149                 OSC_IO_DEBUG(osc, "%lu in flight\n", rpcs_in_flight(cli));
2150
2151                 /* even if we have reached our max in flight RPCs, we still
2152                  * allow all high-priority RPCs through to prevent their
2153                  * starvation and leading to server evicting us for not
2154                  * writing out pages in a timely manner LU-13131 */
2155                 if (osc_max_rpc_in_flight(cli, osc) &&
2156                     list_empty(&osc->oo_hp_exts)) {
2157                         __osc_list_maint(cli, osc);
2158                         break;
2159                 }
2160
2161                 cl_object_get(obj);
2162                 spin_unlock(&cli->cl_loi_list_lock);
2163                 lu_object_ref_add_at(&obj->co_lu, &link, "check", current);
2164
2165                 /* attempt some read/write balancing by alternating between
2166                  * reads and writes in an object.  The makes_rpc checks here
2167                  * would be redundant if we were getting read/write work items
2168                  * instead of objects.  we don't want send_oap_rpc to drain a
2169                  * partial read pending queue when we're given this object to
2170                  * do io on writes while there are cache waiters */
2171                 osc_object_lock(osc);
2172                 if (osc_makes_rpc(cli, osc, OBD_BRW_WRITE)) {
2173                         rc = osc_send_write_rpc(env, cli, osc);
2174                         if (rc < 0) {
2175                                 CERROR("Write request failed with %d\n", rc);
2176
2177                                 /* osc_send_write_rpc failed, mostly because of
2178                                  * memory pressure.
2179                                  *
2180                                  * It can't break here, because if:
2181                                  *  - a page was submitted by osc_io_submit, so
2182                                  *    page locked;
2183                                  *  - no request in flight
2184                                  *  - no subsequent request
2185                                  * The system will be in live-lock state,
2186                                  * because there is no chance to call
2187                                  * osc_io_unplug() and osc_check_rpcs() any
2188                                  * more. pdflush can't help in this case,
2189                                  * because it might be blocked at grabbing
2190                                  * the page lock as we mentioned.
2191                                  *
2192                                  * Anyway, continue to drain pages. */
2193                                 /* break; */
2194                         }
2195                 }
2196                 if (osc_makes_rpc(cli, osc, OBD_BRW_READ)) {
2197                         rc = osc_send_read_rpc(env, cli, osc);
2198                         if (rc < 0)
2199                                 CERROR("Read request failed with %d\n", rc);
2200                 }
2201                 osc_object_unlock(osc);
2202
2203                 osc_list_maint(cli, osc);
2204                 lu_object_ref_del_at(&obj->co_lu, &link, "check", current);
2205                 cl_object_put(env, obj);
2206
2207                 spin_lock(&cli->cl_loi_list_lock);
2208         }
2209 }
2210
2211 int osc_io_unplug0(const struct lu_env *env, struct client_obd *cli,
2212                    struct osc_object *osc, int async)
2213 {
2214         int rc = 0;
2215
2216         if (osc != NULL && osc_list_maint(cli, osc) == 0)
2217                 return 0;
2218
2219         if (!async) {
2220                 spin_lock(&cli->cl_loi_list_lock);
2221                 osc_check_rpcs(env, cli);
2222                 spin_unlock(&cli->cl_loi_list_lock);
2223         } else {
2224                 CDEBUG(D_CACHE, "Queue writeback work for client %p.\n", cli);
2225                 LASSERT(cli->cl_writeback_work != NULL);
2226                 rc = ptlrpcd_queue_work(cli->cl_writeback_work);
2227         }
2228         return rc;
2229 }
2230 EXPORT_SYMBOL(osc_io_unplug0);
2231
2232 int osc_prep_async_page(struct osc_object *osc, struct osc_page *ops,
2233                         struct cl_page *page, loff_t offset)
2234 {
2235         struct osc_async_page *oap = &ops->ops_oap;
2236
2237         ENTRY;
2238         if (!page)
2239                 return round_up(sizeof(*oap), 8);
2240
2241         oap->oap_obj = osc;
2242         oap->oap_page = page->cp_vmpage;
2243         oap->oap_obj_off = offset;
2244         LASSERT(!(offset & ~PAGE_MASK));
2245
2246         /* Count of transient (direct i/o) pages is always stable by the time
2247          * they're submitted.  Setting this here lets us avoid calling
2248          * cl_page_clip later to set this.
2249          */
2250         if (page->cp_type == CPT_TRANSIENT)
2251                 oap->oap_async_flags |= ASYNC_COUNT_STABLE|ASYNC_URGENT|
2252                                         ASYNC_READY;
2253
2254         INIT_LIST_HEAD(&oap->oap_pending_item);
2255         INIT_LIST_HEAD(&oap->oap_rpc_item);
2256
2257         CDEBUG(D_INFO, "oap %p vmpage %p obj off %llu\n",
2258                oap, oap->oap_page, oap->oap_obj_off);
2259         RETURN(0);
2260 }
2261 EXPORT_SYMBOL(osc_prep_async_page);
2262
2263 int osc_queue_async_io(const struct lu_env *env, struct cl_io *io,
2264                        struct osc_page *ops, cl_commit_cbt cb)
2265 {
2266         struct osc_io *oio = osc_env_io(env);
2267         struct osc_extent     *ext = NULL;
2268         struct osc_async_page *oap = &ops->ops_oap;
2269         struct osc_object     *osc = oap->oap_obj;
2270         struct client_obd     *cli = osc_cli(osc);
2271         struct pagevec        *pvec = &osc_env_info(env)->oti_pagevec;
2272         pgoff_t index;
2273         unsigned int tmp;
2274         unsigned int grants = 0;
2275         u32    brw_flags = OBD_BRW_ASYNC;
2276         int    cmd = OBD_BRW_WRITE;
2277         int    need_release = 0;
2278         int    rc = 0;
2279         ENTRY;
2280
2281         if (cli->cl_import == NULL || cli->cl_import->imp_invalid)
2282                 RETURN(-EIO);
2283
2284         if (!list_empty(&oap->oap_pending_item) ||
2285             !list_empty(&oap->oap_rpc_item))
2286                 RETURN(-EBUSY);
2287
2288         /* Set the OBD_BRW_SRVLOCK before the page is queued. */
2289         brw_flags |= ops->ops_srvlock ? OBD_BRW_SRVLOCK : 0;
2290         if (io->ci_noquota) {
2291                 brw_flags |= OBD_BRW_NOQUOTA;
2292                 cmd |= OBD_BRW_NOQUOTA;
2293         }
2294
2295         if (oio->oi_cap_sys_resource) {
2296                 brw_flags |= OBD_BRW_SYS_RESOURCE;
2297                 cmd |= OBD_BRW_SYS_RESOURCE;
2298         }
2299
2300         /* check if the file's owner/group is over quota */
2301         /* do not check for root without root squash, because in this case
2302          * we should bypass quota
2303          */
2304         if ((!oio->oi_cap_sys_resource ||
2305              cli->cl_root_squash || cli->cl_root_prjquota) &&
2306             !io->ci_noquota) {
2307                 struct cl_object *obj;
2308                 struct cl_attr   *attr;
2309                 unsigned int qid[LL_MAXQUOTAS];
2310
2311                 obj = cl_object_top(&osc->oo_cl);
2312                 attr = &osc_env_info(env)->oti_attr;
2313
2314                 cl_object_attr_lock(obj);
2315                 rc = cl_object_attr_get(env, obj, attr);
2316                 cl_object_attr_unlock(obj);
2317
2318                 qid[USRQUOTA] = attr->cat_uid;
2319                 qid[GRPQUOTA] = attr->cat_gid;
2320                 qid[PRJQUOTA] = attr->cat_projid;
2321                 if (rc == 0 && osc_quota_chkdq(cli, qid) == -EDQUOT)
2322                         rc = -EDQUOT;
2323                 if (rc)
2324                         RETURN(rc);
2325         }
2326
2327         oap->oap_cmd = cmd;
2328         oap->oap_page_off = ops->ops_from;
2329         oap->oap_count = ops->ops_to - ops->ops_from + 1;
2330         /* No need to hold a lock here,
2331          * since this page is not in any list yet. */
2332         oap->oap_async_flags = 0;
2333         oap->oap_brw_flags = brw_flags;
2334
2335         OSC_IO_DEBUG(osc, "oap %p page %p added for cmd %d\n",
2336                      oap, oap->oap_page, oap->oap_cmd & OBD_BRW_RWMASK);
2337
2338         index = osc_index(oap2osc(oap));
2339
2340         /* Add this page into extent by the following steps:
2341          * 1. if there exists an active extent for this IO, mostly this page
2342          *    can be added to the active extent and sometimes we need to
2343          *    expand extent to accomodate this page;
2344          * 2. otherwise, a new extent will be allocated. */
2345
2346         ext = oio->oi_active;
2347         if (ext != NULL && ext->oe_start <= index && ext->oe_max_end >= index) {
2348                 /* one chunk plus extent overhead must be enough to write this
2349                  * page */
2350                 grants = (1 << cli->cl_chunkbits) + cli->cl_grant_extent_tax;
2351                 if (ext->oe_end >= index)
2352                         grants = 0;
2353
2354                 /* it doesn't need any grant to dirty this page */
2355                 spin_lock(&cli->cl_loi_list_lock);
2356                 rc = osc_enter_cache_try(cli, oap, grants);
2357                 if (rc == 0) { /* try failed */
2358                         grants = 0;
2359                         need_release = 1;
2360                 } else if (ext->oe_end < index) {
2361                         tmp = grants;
2362                         /* try to expand this extent */
2363                         rc = osc_extent_expand(ext, index, &tmp);
2364                         if (rc < 0) {
2365                                 need_release = 1;
2366                                 /* don't free reserved grant */
2367                         } else {
2368                                 OSC_EXTENT_DUMP(D_CACHE, ext,
2369                                                 "expanded for %lu.\n", index);
2370                                 osc_unreserve_grant_nolock(cli, grants, tmp);
2371                                 grants = 0;
2372                         }
2373                 }
2374                 spin_unlock(&cli->cl_loi_list_lock);
2375                 rc = 0;
2376         } else if (ext != NULL) {
2377                 /* index is located outside of active extent */
2378                 need_release = 1;
2379         }
2380         if (need_release) {
2381                 osc_extent_release(env, ext);
2382                 oio->oi_active = NULL;
2383                 ext = NULL;
2384         }
2385
2386         if (ext == NULL) {
2387                 tmp = (1 << cli->cl_chunkbits) + cli->cl_grant_extent_tax;
2388
2389                 /* try to find new extent to cover this page */
2390                 LASSERT(oio->oi_active == NULL);
2391                 /* we may have allocated grant for this page if we failed
2392                  * to expand the previous active extent. */
2393                 LASSERT(ergo(grants > 0, grants >= tmp));
2394
2395                 rc = 0;
2396
2397                 /* We must not hold a page lock while we do osc_enter_cache()
2398                  * or osc_extent_find(), so we must mark dirty & unlock
2399                  * any pages in the write commit pagevec. */
2400                 if (pagevec_count(pvec)) {
2401                         cb(env, io, pvec);
2402                         pagevec_reinit(pvec);
2403                 }
2404
2405                 if (grants == 0) {
2406                         rc = osc_enter_cache(env, cli, oap, tmp);
2407                         if (rc == 0)
2408                                 grants = tmp;
2409                 }
2410
2411                 tmp = grants;
2412                 if (rc == 0) {
2413                         ext = osc_extent_find(env, osc, index, &tmp);
2414                         if (IS_ERR(ext)) {
2415                                 LASSERT(tmp == grants);
2416                                 osc_exit_cache(cli, oap);
2417                                 rc = PTR_ERR(ext);
2418                                 ext = NULL;
2419                         } else {
2420                                 oio->oi_active = ext;
2421                         }
2422                 }
2423                 if (grants > 0)
2424                         osc_unreserve_grant(cli, grants, tmp);
2425         }
2426
2427         LASSERT(ergo(rc == 0, ext != NULL));
2428         if (ext != NULL) {
2429                 EASSERTF(ext->oe_end >= index && ext->oe_start <= index,
2430                          ext, "index = %lu.\n", index);
2431                 LASSERT((oap->oap_brw_flags & OBD_BRW_FROM_GRANT) != 0);
2432
2433                 osc_object_lock(osc);
2434                 if (ext->oe_nr_pages == 0)
2435                         ext->oe_srvlock = ops->ops_srvlock;
2436                 else
2437                         LASSERT(ext->oe_srvlock == ops->ops_srvlock);
2438                 ++ext->oe_nr_pages;
2439                 list_add_tail(&oap->oap_pending_item, &ext->oe_pages);
2440                 osc_object_unlock(osc);
2441
2442                 if (!ext->oe_layout_version)
2443                         ext->oe_layout_version = io->ci_layout_version;
2444         }
2445
2446         RETURN(rc);
2447 }
2448
2449 int osc_teardown_async_page(const struct lu_env *env,
2450                             struct osc_object *obj, struct osc_page *ops)
2451 {
2452         struct osc_async_page *oap = &ops->ops_oap;
2453         int rc = 0;
2454         ENTRY;
2455
2456         CDEBUG(D_INFO, "teardown oap %p page %p at index %lu.\n",
2457                oap, ops, osc_index(oap2osc(oap)));
2458
2459         if (!list_empty(&oap->oap_rpc_item)) {
2460                 CDEBUG(D_CACHE, "oap %p is not in cache.\n", oap);
2461                 rc = -EBUSY;
2462         } else if (!list_empty(&oap->oap_pending_item)) {
2463                 struct osc_extent *ext = NULL;
2464
2465                 osc_object_lock(obj);
2466                 ext = osc_extent_lookup(obj, osc_index(oap2osc(oap)));
2467                 osc_object_unlock(obj);
2468                 /* only truncated pages are allowed to be taken out.
2469                  * See osc_extent_truncate() and osc_cache_truncate_start()
2470                  * for details. */
2471                 if (ext != NULL && ext->oe_state != OES_TRUNC) {
2472                         OSC_EXTENT_DUMP(D_ERROR, ext, "trunc at %lu.\n",
2473                                         osc_index(oap2osc(oap)));
2474                         rc = -EBUSY;
2475                 }
2476                 if (ext != NULL)
2477                         osc_extent_put(env, ext);
2478         }
2479         RETURN(rc);
2480 }
2481
2482 /**
2483  * This is called when a page is picked up by kernel to write out.
2484  *
2485  * We should find out the corresponding extent and add the whole extent
2486  * into urgent list. The extent may be being truncated or used, handle it
2487  * carefully.
2488  */
2489 int osc_flush_async_page(const struct lu_env *env, struct cl_io *io,
2490                          struct osc_page *ops)
2491 {
2492         struct osc_extent *ext   = NULL;
2493         struct osc_object *obj   = osc_page_object(ops);
2494         struct cl_page    *cp    = ops->ops_cl.cpl_page;
2495         pgoff_t            index = osc_index(ops);
2496         struct osc_async_page *oap = &ops->ops_oap;
2497         bool unplug = false;
2498         int rc = 0;
2499         ENTRY;
2500
2501         osc_object_lock(obj);
2502         ext = osc_extent_lookup(obj, index);
2503         if (ext == NULL) {
2504                 osc_extent_tree_dump(D_ERROR, obj);
2505                 LASSERTF(0, "page index %lu is NOT covered.\n", index);
2506         }
2507
2508         switch (ext->oe_state) {
2509         case OES_RPC:
2510         case OES_LOCK_DONE:
2511                 CL_PAGE_DEBUG(D_ERROR, env, cp, "flush an in-rpc page?\n");
2512                 LASSERT(0);
2513                 break;
2514         case OES_LOCKING:
2515                 /* If we know this extent is being written out, we should abort
2516                  * so that the writer can make this page ready. Otherwise, there
2517                  * exists a deadlock problem because other process can wait for
2518                  * page writeback bit holding page lock; and meanwhile in
2519                  * vvp_page_make_ready(), we need to grab page lock before
2520                  * really sending the RPC. */
2521         case OES_TRUNC:
2522                 /* race with truncate, page will be redirtied */
2523         case OES_ACTIVE:
2524                 /* The extent is active so we need to abort and let the caller
2525                  * re-dirty the page. If we continued on here, and we were the
2526                  * one making the extent active, we could deadlock waiting for
2527                  * the page writeback to clear but it won't because the extent
2528                  * is active and won't be written out. */
2529                 GOTO(out, rc = -EAGAIN);
2530         default:
2531                 break;
2532         }
2533
2534         rc = cl_page_prep(env, io, cp, CRT_WRITE);
2535         if (rc)
2536                 GOTO(out, rc);
2537
2538         oap->oap_async_flags |= ASYNC_READY|ASYNC_URGENT;
2539
2540         if (current->flags & PF_MEMALLOC)
2541                 ext->oe_memalloc = 1;
2542
2543         ext->oe_urgent = 1;
2544         if (ext->oe_state == OES_CACHE) {
2545                 OSC_EXTENT_DUMP(D_CACHE, ext,
2546                                 "flush page %p make it urgent.\n", oap);
2547                 if (list_empty(&ext->oe_link))
2548                         list_add_tail(&ext->oe_link, &obj->oo_urgent_exts);
2549                 unplug = true;
2550         }
2551         rc = 0;
2552         EXIT;
2553
2554 out:
2555         osc_object_unlock(obj);
2556         osc_extent_put(env, ext);
2557         if (unplug)
2558                 osc_io_unplug_async(env, osc_cli(obj), obj);
2559         return rc;
2560 }
2561
2562 int osc_queue_sync_pages(const struct lu_env *env, struct cl_io *io,
2563                          struct osc_object *obj, struct list_head *list,
2564                          int brw_flags)
2565 {
2566         struct osc_io *oio = osc_env_io(env);
2567         struct client_obd     *cli = osc_cli(obj);
2568         struct osc_extent     *ext;
2569         struct osc_async_page *oap;
2570         int     page_count = 0;
2571         int     mppr       = cli->cl_max_pages_per_rpc;
2572         bool    can_merge   = true;
2573         pgoff_t start      = CL_PAGE_EOF;
2574         pgoff_t end        = 0;
2575         struct osc_lock *oscl;
2576         ENTRY;
2577
2578         list_for_each_entry(oap, list, oap_pending_item) {
2579                 struct osc_page *opg = oap2osc_page(oap);
2580                 pgoff_t index = osc_index(opg);
2581
2582                 if (index > end)
2583                         end = index;
2584                 if (index < start)
2585                         start = index;
2586                 ++page_count;
2587                 mppr <<= (page_count > mppr);
2588
2589                 if (unlikely(opg->ops_from > 0 ||
2590                              opg->ops_to < PAGE_SIZE - 1))
2591                         can_merge = false;
2592         }
2593
2594         ext = osc_extent_alloc(obj);
2595         if (ext == NULL) {
2596                 struct osc_async_page *tmp;
2597
2598                 list_for_each_entry_safe(oap, tmp, list, oap_pending_item) {
2599                         list_del_init(&oap->oap_pending_item);
2600                         osc_ap_completion(env, cli, oap, 0, -ENOMEM);
2601                 }
2602                 RETURN(-ENOMEM);
2603         }
2604
2605         ext->oe_rw = !!(brw_flags & OBD_BRW_READ);
2606         ext->oe_sync = 1;
2607         ext->oe_no_merge = !can_merge;
2608         ext->oe_urgent = 1;
2609         ext->oe_start = start;
2610         ext->oe_end = ext->oe_max_end = end;
2611         ext->oe_obj = obj;
2612         ext->oe_srvlock = !!(brw_flags & OBD_BRW_SRVLOCK);
2613         ext->oe_ndelay = !!(brw_flags & OBD_BRW_NDELAY);
2614         ext->oe_dio = !!(brw_flags & OBD_BRW_NOCACHE);
2615         oscl = oio->oi_write_osclock ? : oio->oi_read_osclock;
2616         if (oscl && oscl->ols_dlmlock != NULL) {
2617                 ext->oe_dlmlock = LDLM_LOCK_GET(oscl->ols_dlmlock);
2618                 lu_ref_add(&ext->oe_dlmlock->l_reference, "osc_extent", ext);
2619         }
2620         if (ext->oe_dio && !ext->oe_rw) { /* direct io write */
2621                 int grants;
2622                 int ppc;
2623
2624                 ppc = 1 << (cli->cl_chunkbits - PAGE_SHIFT);
2625                 grants = cli->cl_grant_extent_tax;
2626                 grants += (1 << cli->cl_chunkbits) *
2627                         ((page_count + ppc - 1) / ppc);
2628
2629                 CDEBUG(D_CACHE, "requesting %d bytes grant\n", grants);
2630                 spin_lock(&cli->cl_loi_list_lock);
2631                 if (osc_reserve_grant(cli, grants) == 0) {
2632                         list_for_each_entry(oap, list, oap_pending_item) {
2633                                 osc_consume_write_grant(cli,
2634                                                         &oap->oap_brw_page);
2635                         }
2636                         atomic_long_add(page_count, &obd_dirty_pages);
2637                         osc_unreserve_grant_nolock(cli, grants, 0);
2638                         ext->oe_grants = grants;
2639                 } else {
2640                         /* We cannot report ENOSPC correctly if we do parallel
2641                          * DIO (async RPC submission), so turn off parallel dio
2642                          * if there is not sufficient grant available.  This
2643                          * makes individual RPCs synchronous.
2644                          */
2645                         io->ci_parallel_dio = false;
2646                         CDEBUG(D_CACHE,
2647                         "not enough grant available, switching to sync for this i/o\n");
2648                 }
2649                 spin_unlock(&cli->cl_loi_list_lock);
2650                 osc_update_next_shrink(cli);
2651         }
2652
2653         ext->oe_is_rdma_only = !!(brw_flags & OBD_BRW_RDMA_ONLY);
2654         ext->oe_nr_pages = page_count;
2655         ext->oe_mppr = mppr;
2656         list_splice_init(list, &ext->oe_pages);
2657         ext->oe_layout_version = io->ci_layout_version;
2658
2659         osc_object_lock(obj);
2660         /* Reuse the initial refcount for RPC, don't drop it */
2661         osc_extent_state_set(ext, OES_LOCK_DONE);
2662         if (!ext->oe_rw) { /* write */
2663                 if (!ext->oe_srvlock && !ext->oe_dio) {
2664                         /* The most likely case here is from lack of grants
2665                          * so we are either out of quota or out of space.
2666                          * Since this means we are holding locks across
2667                          * potentially multi-striped IO, we must send out
2668                          * everything out instantly to avoid prolonged
2669                          * waits resulting in lock eviction (likely since
2670                          * the extended wait in osc_cache_enter() did not
2671                          * yield any additional grant due to a timeout.
2672                          * LU-13131 */
2673                         ext->oe_hp = 1;
2674                         list_add_tail(&ext->oe_link, &obj->oo_hp_exts);
2675                 } else {
2676                         list_add_tail(&ext->oe_link, &obj->oo_urgent_exts);
2677                 }
2678                 osc_update_pending(obj, OBD_BRW_WRITE, page_count);
2679         } else {
2680                 list_add_tail(&ext->oe_link, &obj->oo_reading_exts);
2681                 osc_update_pending(obj, OBD_BRW_READ, page_count);
2682         }
2683         osc_object_unlock(obj);
2684
2685         osc_io_unplug_async(env, cli, obj);
2686         RETURN(0);
2687 }
2688
2689 /**
2690  * Called by osc_io_setattr_start() to freeze and destroy covering extents.
2691  */
2692 int osc_cache_truncate_start(const struct lu_env *env, struct osc_object *obj,
2693                              __u64 size, struct osc_extent **extp)
2694 {
2695         struct client_obd *cli = osc_cli(obj);
2696         struct osc_extent *ext;
2697         struct osc_extent *waiting = NULL;
2698         pgoff_t index;
2699         LIST_HEAD(list);
2700         int result = 0;
2701         bool partial;
2702         ENTRY;
2703
2704         /* pages with index greater or equal to index will be truncated. */
2705         index = size >> PAGE_SHIFT;
2706         partial = size > (index << PAGE_SHIFT);
2707
2708 again:
2709         osc_object_lock(obj);
2710         ext = osc_extent_search(obj, index);
2711         if (ext == NULL)
2712                 ext = first_extent(obj);
2713         else if (ext->oe_end < index)
2714                 ext = next_extent(ext);
2715         while (ext != NULL) {
2716                 EASSERT(ext->oe_state != OES_TRUNC, ext);
2717
2718                 if (ext->oe_state > OES_CACHE || ext->oe_urgent) {
2719                         /* if ext is in urgent state, it means there must exist
2720                          * a page already having been flushed by write_page().
2721                          * We have to wait for this extent because we can't
2722                          * truncate that page. */
2723                         OSC_EXTENT_DUMP(D_CACHE, ext,
2724                                         "waiting for busy extent\n");
2725                         waiting = osc_extent_get(ext);
2726                         break;
2727                 }
2728
2729                 OSC_EXTENT_DUMP(D_CACHE, ext, "try to trunc:%llu.\n", size);
2730
2731                 osc_extent_get(ext);
2732                 if (ext->oe_state == OES_ACTIVE) {
2733                         /* though we grab inode mutex for write path, but we
2734                          * release it before releasing extent(in osc_io_end()),
2735                          * so there is a race window that an extent is still
2736                          * in OES_ACTIVE when truncate starts. */
2737                         LASSERT(!ext->oe_trunc_pending);
2738                         ext->oe_trunc_pending = 1;
2739                 } else {
2740                         EASSERT(ext->oe_state == OES_CACHE, ext);
2741                         osc_extent_state_set(ext, OES_TRUNC);
2742                         osc_update_pending(obj, OBD_BRW_WRITE,
2743                                            -ext->oe_nr_pages);
2744                 }
2745                 /* This extent could be on the full extents list, that's OK */
2746                 EASSERT(!ext->oe_hp && !ext->oe_urgent, ext);
2747                 if (!list_empty(&ext->oe_link))
2748                         list_move_tail(&ext->oe_link, &list);
2749                 else
2750                         list_add_tail(&ext->oe_link, &list);
2751
2752                 ext = next_extent(ext);
2753         }
2754         osc_object_unlock(obj);
2755
2756         osc_list_maint(cli, obj);
2757
2758         while ((ext = list_first_entry_or_null(&list,
2759                                                struct osc_extent,
2760                                                oe_link)) != NULL) {
2761                 int rc;
2762
2763                 list_del_init(&ext->oe_link);
2764
2765                 /* extent may be in OES_ACTIVE state because inode mutex
2766                  * is released before osc_io_end() in file write case */
2767                 if (ext->oe_state != OES_TRUNC)
2768                         osc_extent_wait(env, ext, OES_TRUNC);
2769
2770                 rc = osc_extent_truncate(ext, index, partial);
2771                 if (rc < 0) {
2772                         if (result == 0)
2773                                 result = rc;
2774
2775                         OSC_EXTENT_DUMP(D_ERROR, ext,
2776                                         "truncate error %d\n", rc);
2777                 } else if (ext->oe_nr_pages == 0) {
2778                         osc_extent_remove(ext);
2779                 } else {
2780                         /* this must be an overlapped extent which means only
2781                          * part of pages in this extent have been truncated.
2782                          */
2783                         EASSERTF(ext->oe_start <= index, ext,
2784                                  "trunc index = %lu/%d.\n", index, partial);
2785                         /* fix index to skip this partially truncated extent */
2786                         index = ext->oe_end + 1;
2787                         partial = false;
2788
2789                         /* we need to hold this extent in OES_TRUNC state so
2790                          * that no writeback will happen. This is to avoid
2791                          * BUG 17397.
2792                          * Only partial truncate can reach here, if @size is
2793                          * not zero, the caller should provide a valid @extp. */
2794                         LASSERT(*extp == NULL);
2795                         *extp = osc_extent_get(ext);
2796                         OSC_EXTENT_DUMP(D_CACHE, ext,
2797                                         "trunc at %llu\n", size);
2798                 }
2799                 osc_extent_put(env, ext);
2800         }
2801         if (waiting != NULL) {
2802                 int rc;
2803
2804                 /* ignore the result of osc_extent_wait the write initiator
2805                  * should take care of it. */
2806                 rc = osc_extent_wait(env, waiting, OES_INV);
2807                 if (rc < 0)
2808                         OSC_EXTENT_DUMP(D_CACHE, waiting, "error: %d.\n", rc);
2809
2810                 osc_extent_put(env, waiting);
2811                 waiting = NULL;
2812                 goto again;
2813         }
2814         RETURN(result);
2815 }
2816 EXPORT_SYMBOL(osc_cache_truncate_start);
2817
2818 /**
2819  * Called after osc_io_setattr_end to add oio->oi_trunc back to cache.
2820  */
2821 void osc_cache_truncate_end(const struct lu_env *env, struct osc_extent *ext)
2822 {
2823         if (ext != NULL) {
2824                 struct osc_object *obj = ext->oe_obj;
2825                 bool unplug = false;
2826
2827                 EASSERT(ext->oe_nr_pages > 0, ext);
2828                 EASSERT(ext->oe_state == OES_TRUNC, ext);
2829                 EASSERT(!ext->oe_urgent, ext);
2830
2831                 OSC_EXTENT_DUMP(D_CACHE, ext, "trunc -> cache.\n");
2832                 osc_object_lock(obj);
2833                 osc_extent_state_set(ext, OES_CACHE);
2834                 if (ext->oe_fsync_wait && !ext->oe_urgent) {
2835                         ext->oe_urgent = 1;
2836                         list_move_tail(&ext->oe_link, &obj->oo_urgent_exts);
2837                         unplug = true;
2838                 }
2839                 osc_update_pending(obj, OBD_BRW_WRITE, ext->oe_nr_pages);
2840                 osc_object_unlock(obj);
2841                 osc_extent_put(env, ext);
2842
2843                 if (unplug)
2844                         osc_io_unplug_async(env, osc_cli(obj), obj);
2845         }
2846 }
2847
2848 /**
2849  * Wait for extents in a specific range to be written out.
2850  * The caller must have called osc_cache_writeback_range() to issue IO
2851  * otherwise it will take a long time for this function to finish.
2852  *
2853  * Caller must hold inode_mutex , or cancel exclusive dlm lock so that
2854  * nobody else can dirty this range of file while we're waiting for
2855  * extents to be written.
2856  */
2857 int osc_cache_wait_range(const struct lu_env *env, struct osc_object *obj,
2858                          pgoff_t start, pgoff_t end)
2859 {
2860         struct osc_extent *ext;
2861         pgoff_t index = start;
2862         int     result = 0;
2863         ENTRY;
2864
2865 again:
2866         osc_object_lock(obj);
2867         ext = osc_extent_search(obj, index);
2868         if (ext == NULL)
2869                 ext = first_extent(obj);
2870         else if (ext->oe_end < index)
2871                 ext = next_extent(ext);
2872         while (ext != NULL) {
2873                 int rc;
2874
2875                 if (ext->oe_start > end)
2876                         break;
2877
2878                 if (!ext->oe_fsync_wait) {
2879                         ext = next_extent(ext);
2880                         continue;
2881                 }
2882
2883                 EASSERT(ergo(ext->oe_state == OES_CACHE,
2884                              ext->oe_hp || ext->oe_urgent), ext);
2885                 EASSERT(ergo(ext->oe_state == OES_ACTIVE,
2886                              !ext->oe_hp && ext->oe_urgent), ext);
2887
2888                 index = ext->oe_end + 1;
2889                 osc_extent_get(ext);
2890                 osc_object_unlock(obj);
2891
2892                 rc = osc_extent_wait(env, ext, OES_INV);
2893                 if (result == 0)
2894                         result = rc;
2895                 osc_extent_put(env, ext);
2896                 goto again;
2897         }
2898         osc_object_unlock(obj);
2899
2900         OSC_IO_DEBUG(obj, "sync file range.\n");
2901         RETURN(result);
2902 }
2903 EXPORT_SYMBOL(osc_cache_wait_range);
2904
2905 /**
2906  * Called to write out a range of osc object.
2907  *
2908  * @hp     : should be set this is caused by lock cancel;
2909  * @discard: is set if dirty pages should be dropped - file will be deleted or
2910  *         truncated, this implies there is no partially discarding extents.
2911  *
2912  * Return how many pages will be issued, or error code if error occurred.
2913  */
2914 int osc_cache_writeback_range(const struct lu_env *env, struct osc_object *obj,
2915                               pgoff_t start, pgoff_t end, int hp, int discard)
2916 {
2917         struct osc_extent *ext;
2918         LIST_HEAD(discard_list);
2919         bool unplug = false;
2920         int result = 0;
2921         ENTRY;
2922
2923         osc_object_lock(obj);
2924         ext = osc_extent_search(obj, start);
2925         if (ext == NULL)
2926                 ext = first_extent(obj);
2927         else if (ext->oe_end < start)
2928                 ext = next_extent(ext);
2929         while (ext != NULL) {
2930                 if (ext->oe_start > end)
2931                         break;
2932
2933                 ext->oe_fsync_wait = 1;
2934                 switch (ext->oe_state) {
2935                 case OES_CACHE:
2936                         result += ext->oe_nr_pages;
2937                         if (!discard) {
2938                                 struct list_head *list = NULL;
2939                                 if (hp) {
2940                                         EASSERT(!ext->oe_hp, ext);
2941                                         ext->oe_hp = 1;
2942                                         list = &obj->oo_hp_exts;
2943                                 } else if (!ext->oe_urgent && !ext->oe_hp) {
2944                                         ext->oe_urgent = 1;
2945                                         list = &obj->oo_urgent_exts;
2946                                 }
2947                                 if (list != NULL)
2948                                         list_move_tail(&ext->oe_link, list);
2949                                 unplug = true;
2950                         } else {
2951                                 struct client_obd *cli = osc_cli(obj);
2952                                 int pcc_bits = cli->cl_chunkbits - PAGE_SHIFT;
2953                                 pgoff_t align_by = (1 << pcc_bits);
2954                                 pgoff_t a_start = round_down(start, align_by);
2955                                 pgoff_t a_end = round_up(end, align_by);
2956
2957                                 /* overflow case */
2958                                 if (end && !a_end)
2959                                         a_end = CL_PAGE_EOF;
2960                                 /* the only discarder is lock cancelling, so
2961                                  * [start, end], aligned by chunk size, must
2962                                  * contain this extent */
2963                                 LASSERTF(ext->oe_start >= a_start &&
2964                                          ext->oe_end <= a_end,
2965                                          "ext [%lu, %lu] reg [%lu, %lu] "
2966                                          "orig [%lu %lu] align %lu bits "
2967                                          "%d\n", ext->oe_start, ext->oe_end,
2968                                          a_start, a_end, start, end,
2969                                          align_by, pcc_bits);
2970                                 osc_extent_state_set(ext, OES_LOCKING);
2971                                 ext->oe_owner = current;
2972                                 list_move_tail(&ext->oe_link,
2973                                                    &discard_list);
2974                                 osc_update_pending(obj, OBD_BRW_WRITE,
2975                                                    -ext->oe_nr_pages);
2976                         }
2977                         break;
2978                 case OES_ACTIVE:
2979                         /* It's pretty bad to wait for ACTIVE extents, because
2980                          * we don't know how long we will wait for it to be
2981                          * flushed since it may be blocked at awaiting more
2982                          * grants. We do this for the correctness of fsync. */
2983                         LASSERT(hp == 0 && discard == 0);
2984                         ext->oe_urgent = 1;
2985                         break;
2986                 case OES_TRUNC:
2987                         /* this extent is being truncated, can't do anything
2988                          * for it now. it will be set to urgent after truncate
2989                          * is finished in osc_cache_truncate_end(). */
2990                 default:
2991                         break;
2992                 }
2993                 ext = next_extent(ext);
2994         }
2995         osc_object_unlock(obj);
2996
2997         LASSERT(ergo(!discard, list_empty(&discard_list)));
2998         if (!list_empty(&discard_list)) {
2999                 struct osc_extent *tmp;
3000                 int rc;
3001
3002                 osc_list_maint(osc_cli(obj), obj);
3003                 list_for_each_entry_safe(ext, tmp, &discard_list, oe_link) {
3004                         list_del_init(&ext->oe_link);
3005                         EASSERT(ext->oe_state == OES_LOCKING, ext);
3006
3007                         /* Discard caching pages. We don't actually write this
3008                          * extent out but we complete it as if we did. */
3009                         rc = osc_extent_make_ready(env, ext);
3010                         if (unlikely(rc < 0)) {
3011                                 OSC_EXTENT_DUMP(D_ERROR, ext,
3012                                                 "make_ready returned %d\n", rc);
3013                                 if (result >= 0)
3014                                         result = rc;
3015                         }
3016
3017                         /* finish the extent as if the pages were sent */
3018                         osc_extent_finish(env, ext, 0, 0);
3019                 }
3020         }
3021
3022         if (unplug)
3023                 osc_io_unplug(env, osc_cli(obj), obj);
3024
3025         if (hp || discard) {
3026                 int rc;
3027                 rc = osc_cache_wait_range(env, obj, start, end);
3028                 if (result >= 0 && rc < 0)
3029                         result = rc;
3030         }
3031
3032         OSC_IO_DEBUG(obj, "pageout [%lu, %lu], %d.\n", start, end, result);
3033         RETURN(result);
3034 }
3035 EXPORT_SYMBOL(osc_cache_writeback_range);
3036
3037 /**
3038  * Returns a list of pages by a given [start, end] of \a obj.
3039  *
3040  * Gang tree lookup (radix_tree_gang_lookup()) optimization is absolutely
3041  * crucial in the face of [offset, EOF] locks.
3042  *
3043  * Return at least one page in @queue unless there is no covered page.
3044  */
3045 bool osc_page_gang_lookup(const struct lu_env *env, struct cl_io *io,
3046                           struct osc_object *osc, pgoff_t start, pgoff_t end,
3047                           osc_page_gang_cbt cb, void *cbdata)
3048 {
3049         struct osc_page *ops;
3050         struct pagevec  *pagevec;
3051         void            **pvec;
3052         pgoff_t         idx;
3053         unsigned int    nr;
3054         unsigned int    i;
3055         unsigned int    j;
3056         bool            res = true;
3057         bool            tree_lock = true;
3058         ENTRY;
3059
3060         idx = start;
3061         pvec = osc_env_info(env)->oti_pvec;
3062         pagevec = &osc_env_info(env)->oti_pagevec;
3063         ll_pagevec_init(pagevec, 0);
3064         spin_lock(&osc->oo_tree_lock);
3065         while ((nr = radix_tree_gang_lookup(&osc->oo_tree, pvec,
3066                                             idx, OTI_PVEC_SIZE)) > 0) {
3067                 struct cl_page *page;
3068                 bool end_of_region = false;
3069
3070                 for (i = 0, j = 0; i < nr; ++i) {
3071                         ops = pvec[i];
3072                         pvec[i] = NULL;
3073
3074                         idx = osc_index(ops);
3075                         if (idx > end) {
3076                                 end_of_region = true;
3077                                 break;
3078                         }
3079
3080                         page = ops->ops_cl.cpl_page;
3081                         LASSERT(page->cp_type == CPT_CACHEABLE);
3082                         if (page->cp_state == CPS_FREEING)
3083                                 continue;
3084
3085                         cl_page_get(page);
3086                         lu_ref_add_atomic(&page->cp_reference,
3087                                           "gang_lookup", current);
3088                         pvec[j++] = ops;
3089                 }
3090                 ++idx;
3091
3092                 /*
3093                  * Here a delicate locking dance is performed. Current thread
3094                  * holds a reference to a page, but has to own it before it
3095                  * can be placed into queue. Owning implies waiting, so
3096                  * radix-tree lock is to be released. After a wait one has to
3097                  * check that pages weren't truncated (cl_page_own() returns
3098                  * error in the latter case).
3099                  */
3100                 spin_unlock(&osc->oo_tree_lock);
3101                 tree_lock = false;
3102
3103                 res = (*cb)(env, io, pvec, j, cbdata);
3104
3105                 for (i = 0; i < j; ++i) {
3106                         ops = pvec[i];
3107                         page = ops->ops_cl.cpl_page;
3108                         lu_ref_del(&page->cp_reference, "gang_lookup", current);
3109                         cl_pagevec_put(env, page, pagevec);
3110                 }
3111                 pagevec_release(pagevec);
3112
3113                 if (nr < OTI_PVEC_SIZE || end_of_region)
3114                         break;
3115
3116                 if (!res)
3117                         break;
3118
3119                 CFS_FAIL_TIMEOUT(OBD_FAIL_OSC_SLOW_PAGE_EVICT,
3120                                  cfs_fail_val ?: 20);
3121
3122                 if (io->ci_type == CIT_MISC &&
3123                     io->u.ci_misc.lm_next_rpc_time &&
3124                     ktime_get_seconds() > io->u.ci_misc.lm_next_rpc_time) {
3125                         osc_send_empty_rpc(osc, idx << PAGE_SHIFT);
3126                         io->u.ci_misc.lm_next_rpc_time = ktime_get_seconds() +
3127                                                          5 * obd_timeout / 16;
3128                 }
3129
3130                 if (need_resched())
3131                         cond_resched();
3132
3133                 spin_lock(&osc->oo_tree_lock);
3134                 tree_lock = true;
3135         }
3136         if (tree_lock)
3137                 spin_unlock(&osc->oo_tree_lock);
3138         RETURN(res);
3139 }
3140 EXPORT_SYMBOL(osc_page_gang_lookup);
3141
3142 /**
3143  * Check if page @page is covered by an extra lock or discard it.
3144  */
3145 static bool check_and_discard_cb(const struct lu_env *env, struct cl_io *io,
3146                                  void **pvec, int count, void *cbdata)
3147 {
3148         struct osc_thread_info *info = osc_env_info(env);
3149         struct osc_object *osc = cbdata;
3150         int i;
3151
3152         for (i = 0; i < count; i++) {
3153                 struct osc_page *ops = pvec[i];
3154                 struct cl_page *page = ops->ops_cl.cpl_page;
3155                 pgoff_t index = osc_index(ops);
3156                 bool discard = false;
3157
3158                 /* negative lock caching */
3159                 if (index < info->oti_ng_index) {
3160                         discard = true;
3161                 } else if (index >= info->oti_fn_index) {
3162                         struct ldlm_lock *tmp;
3163                         /* refresh non-overlapped index */
3164                         tmp = osc_dlmlock_at_pgoff(env, osc, index,
3165                                         OSC_DAP_FL_TEST_LOCK |
3166                                         OSC_DAP_FL_AST |
3167                                         OSC_DAP_FL_RIGHT);
3168                         if (tmp != NULL) {
3169                                 __u64 end =
3170                                         tmp->l_policy_data.l_extent.end;
3171                                 __u64 start =
3172                                         tmp->l_policy_data.l_extent.start;
3173
3174                                 /* no lock covering this page */
3175                                 if (index < start >> PAGE_SHIFT) {
3176                                         /* no lock at @index,
3177                                          * first lock at @start
3178                                          */
3179                                         info->oti_ng_index =
3180                                                 start >> PAGE_SHIFT;
3181                                         discard = true;
3182                                 } else {
3183                                         /* Cache the first-non-overlapped
3184                                          * index so as to skip all pages
3185                                          * within [index, oti_fn_index).
3186                                          * This is safe because if tmp lock
3187                                          * is canceled, it will discard these
3188                                          * pages.
3189                                          */
3190                                         info->oti_fn_index =
3191                                                 (end + 1) >> PAGE_SHIFT;
3192                                         if (end == OBD_OBJECT_EOF)
3193                                                 info->oti_fn_index =
3194                                                         CL_PAGE_EOF;
3195                                 }
3196                                 LDLM_LOCK_PUT(tmp);
3197                         } else {
3198                                 info->oti_ng_index = CL_PAGE_EOF;
3199                                 discard = true;
3200                         }
3201                 }
3202
3203                 if (discard) {
3204                         if (cl_page_own(env, io, page) == 0) {
3205                                 cl_page_discard(env, io, page);
3206                                 cl_page_disown(env, io, page);
3207                         } else {
3208                                 LASSERT(page->cp_state == CPS_FREEING);
3209                         }
3210                 }
3211
3212                 info->oti_next_index = index + 1;
3213         }
3214         return true;
3215 }
3216
3217 bool osc_discard_cb(const struct lu_env *env, struct cl_io *io,
3218                     void **pvec, int count, void *cbdata)
3219 {
3220         struct osc_thread_info *info = osc_env_info(env);
3221         int i;
3222
3223         for (i = 0; i < count; i++) {
3224                 struct osc_page *ops = pvec[i];
3225                 struct cl_page *page = ops->ops_cl.cpl_page;
3226
3227                 /* page is top page. */
3228                 info->oti_next_index = osc_index(ops) + 1;
3229                 if (cl_page_own(env, io, page) == 0) {
3230                         if (!ergo(page->cp_type == CPT_CACHEABLE,
3231                                   !PageDirty(cl_page_vmpage(page))))
3232                                 CL_PAGE_DEBUG(D_ERROR, env, page,
3233                                               "discard dirty page?\n");
3234
3235                         /* discard the page */
3236                         cl_page_discard(env, io, page);
3237                         cl_page_disown(env, io, page);
3238                 } else {
3239                         LASSERT(page->cp_state == CPS_FREEING);
3240                 }
3241         }
3242
3243         return true;
3244 }
3245 EXPORT_SYMBOL(osc_discard_cb);
3246
3247 /**
3248  * Discard pages protected by the given lock. This function traverses radix
3249  * tree to find all covering pages and discard them. If a page is being covered
3250  * by other locks, it should remain in cache.
3251  *
3252  * If error happens on any step, the process continues anyway (the reasoning
3253  * behind this being that lock cancellation cannot be delayed indefinitely).
3254  */
3255 int osc_lock_discard_pages(const struct lu_env *env, struct osc_object *osc,
3256                            pgoff_t start, pgoff_t end, bool discard)
3257 {
3258         struct osc_thread_info *info = osc_env_info(env);
3259         struct cl_io *io = osc_env_thread_io(env);
3260         osc_page_gang_cbt cb;
3261         int result;
3262
3263         ENTRY;
3264
3265         io->ci_obj = cl_object_top(osc2cl(osc));
3266         io->ci_ignore_layout = 1;
3267         io->u.ci_misc.lm_next_rpc_time = ktime_get_seconds() +
3268                                          5 * obd_timeout / 16;
3269         result = cl_io_init(env, io, CIT_MISC, io->ci_obj);
3270         if (result != 0)
3271                 GOTO(out, result);
3272
3273         cb = discard ? osc_discard_cb : check_and_discard_cb;
3274         info->oti_fn_index = info->oti_next_index = start;
3275         info->oti_ng_index = 0;
3276
3277         osc_page_gang_lookup(env, io, osc,
3278                              info->oti_next_index, end, cb, osc);
3279 out:
3280         cl_io_fini(env, io);
3281         RETURN(result);
3282 }
3283
3284
3285 /** @} osc */