lustre/osc/osc_cache.c

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see
  18  * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
  19  *
  20  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  21  * CA 95054 USA or visit www.sun.com if you need additional information or
  22  * have any questions.
  23  *
  24  * GPL HEADER END
  25  */
  26 /*
  27  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  28  * Use is subject to license terms.
  29  *
  30  * Copyright (c) 2012, 2015, Intel Corporation.
  31  *
  32  */
  33 /*
  34  * This file is part of Lustre, http://www.lustre.org/
  35  * Lustre is a trademark of Sun Microsystems, Inc.
  36  *
  37  * osc cache management.
  38  *
  39  * Author: Jinshan Xiong <jinshan.xiong@whamcloud.com>
  40  */
  41
  42 #define DEBUG_SUBSYSTEM S_OSC
  43
  44 #include "osc_cl_internal.h"
  45 #include "osc_internal.h"
  46
  47 static int extent_debug; /* set it to be true for more debug */
  48
  49 static void osc_update_pending(struct osc_object *obj, int cmd, int delta);
  50 static int osc_extent_wait(const struct lu_env *env, struct osc_extent *ext,
  51                            enum osc_extent_state state);
  52 static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
  53                               struct osc_async_page *oap, int sent, int rc);
  54 static int osc_make_ready(const struct lu_env *env, struct osc_async_page *oap,
  55                           int cmd);
  56 static int osc_refresh_count(const struct lu_env *env,
  57                              struct osc_async_page *oap, int cmd);
  58 static int osc_io_unplug_async(const struct lu_env *env,
  59                                struct client_obd *cli, struct osc_object *osc);
  60 static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
  61                            unsigned int lost_grant);
  62
  63 static void osc_extent_tree_dump0(int level, struct osc_object *obj,
  64                                   const char *func, int line);
  65 #define osc_extent_tree_dump(lvl, obj) \
  66         osc_extent_tree_dump0(lvl, obj, __func__, __LINE__)
  67
  68 /** \addtogroup osc
  69  *  @{
  70  */
  71
  72 /* ------------------ osc extent ------------------ */
  73 static inline char *ext_flags(struct osc_extent *ext, char *flags)
  74 {
  75         char *buf = flags;
  76         *buf++ = ext->oe_rw ? 'r' : 'w';
  77         if (ext->oe_intree)
  78                 *buf++ = 'i';
  79         if (ext->oe_sync)
  80                 *buf++ = 'S';
  81         if (ext->oe_srvlock)
  82                 *buf++ = 's';
  83         if (ext->oe_hp)
  84                 *buf++ = 'h';
  85         if (ext->oe_urgent)
  86                 *buf++ = 'u';
  87         if (ext->oe_memalloc)
  88                 *buf++ = 'm';
  89         if (ext->oe_trunc_pending)
  90                 *buf++ = 't';
  91         if (ext->oe_fsync_wait)
  92                 *buf++ = 'Y';
  93         *buf = 0;
  94         return flags;
  95 }
  96
  97 static inline char list_empty_marker(struct list_head *list)
  98 {
  99         return list_empty(list) ? '-' : '+';
 100 }
 101
 102 #define EXTSTR       "[%lu -> %lu/%lu]"
 103 #define EXTPARA(ext) (ext)->oe_start, (ext)->oe_end, (ext)->oe_max_end
 104 static const char *oes_strings[] = {
 105         "inv", "active", "cache", "locking", "lockdone", "rpc", "trunc", NULL };
 106
 107 #define OSC_EXTENT_DUMP(lvl, extent, fmt, ...) do {                           \
 108         struct osc_extent *__ext = (extent);                                  \
 109         char __buf[16];                                                       \
 110                                                                               \
 111         CDEBUG(lvl,                                                           \
 112                 "extent %p@{" EXTSTR ", "                                     \
 113                 "[%d|%d|%c|%s|%s|%p], [%d|%d|%c|%c|%p|%u|%p]} " fmt,          \
 114                 /* ----- extent part 0 ----- */                               \
 115                 __ext, EXTPARA(__ext),                                        \
 116                 /* ----- part 1 ----- */                                      \
 117                 atomic_read(&__ext->oe_refc),                         \
 118                 atomic_read(&__ext->oe_users),                        \
 119                 list_empty_marker(&__ext->oe_link),                           \
 120                 oes_strings[__ext->oe_state], ext_flags(__ext, __buf),        \
 121                 __ext->oe_obj,                                                \
 122                 /* ----- part 2 ----- */                                      \
 123                 __ext->oe_grants, __ext->oe_nr_pages,                         \
 124                 list_empty_marker(&__ext->oe_pages),                          \
 125                 waitqueue_active(&__ext->oe_waitq) ? '+' : '-',               \
 126                 __ext->oe_dlmlock, __ext->oe_mppr, __ext->oe_owner,           \
 127                 /* ----- part 4 ----- */                                      \
 128                 ## __VA_ARGS__);                                              \
 129         if (lvl == D_ERROR && __ext->oe_dlmlock != NULL)                      \
 130                 LDLM_ERROR(__ext->oe_dlmlock, "extent: %p\n", __ext);         \
 131         else                                                                  \
 132                 LDLM_DEBUG(__ext->oe_dlmlock, "extent: %p\n", __ext);         \
 133 } while (0)
 134
 135 #undef EASSERTF
 136 #define EASSERTF(expr, ext, fmt, args...) do {                          \
 137         if (!(expr)) {                                                  \
 138                 OSC_EXTENT_DUMP(D_ERROR, (ext), fmt, ##args);           \
 139                 osc_extent_tree_dump(D_ERROR, (ext)->oe_obj);           \
 140                 LASSERT(expr);                                          \
 141         }                                                               \
 142 } while (0)
 143
 144 #undef EASSERT
 145 #define EASSERT(expr, ext) EASSERTF(expr, ext, "\n")
 146
 147 static inline struct osc_extent *rb_extent(struct rb_node *n)
 148 {
 149         if (n == NULL)
 150                 return NULL;
 151
 152         return container_of(n, struct osc_extent, oe_node);
 153 }
 154
 155 static inline struct osc_extent *next_extent(struct osc_extent *ext)
 156 {
 157         if (ext == NULL)
 158                 return NULL;
 159
 160         LASSERT(ext->oe_intree);
 161         return rb_extent(rb_next(&ext->oe_node));
 162 }
 163
 164 static inline struct osc_extent *prev_extent(struct osc_extent *ext)
 165 {
 166         if (ext == NULL)
 167                 return NULL;
 168
 169         LASSERT(ext->oe_intree);
 170         return rb_extent(rb_prev(&ext->oe_node));
 171 }
 172
 173 static inline struct osc_extent *first_extent(struct osc_object *obj)
 174 {
 175         return rb_extent(rb_first(&obj->oo_root));
 176 }
 177
 178 /* object must be locked by caller. */
 179 static int osc_extent_sanity_check0(struct osc_extent *ext,
 180                                     const char *func, const int line)
 181 {
 182         struct osc_object *obj = ext->oe_obj;
 183         struct osc_async_page *oap;
 184         size_t page_count;
 185         int rc = 0;
 186
 187         if (!osc_object_is_locked(obj))
 188                 GOTO(out, rc = 9);
 189
 190         if (ext->oe_state >= OES_STATE_MAX)
 191                 GOTO(out, rc = 10);
 192
 193         if (atomic_read(&ext->oe_refc) <= 0)
 194                 GOTO(out, rc = 20);
 195
 196         if (atomic_read(&ext->oe_refc) < atomic_read(&ext->oe_users))
 197                 GOTO(out, rc = 30);
 198
 199         switch (ext->oe_state) {
 200         case OES_INV:
 201                 if (ext->oe_nr_pages > 0 || !list_empty(&ext->oe_pages))
 202                         GOTO(out, rc = 35);
 203                 GOTO(out, rc = 0);
 204                 break;
 205         case OES_ACTIVE:
 206                 if (atomic_read(&ext->oe_users) == 0)
 207                         GOTO(out, rc = 40);
 208                 if (ext->oe_hp)
 209                         GOTO(out, rc = 50);
 210                 if (ext->oe_fsync_wait && !ext->oe_urgent)
 211                         GOTO(out, rc = 55);
 212                 break;
 213         case OES_CACHE:
 214                 if (ext->oe_grants == 0)
 215                         GOTO(out, rc = 60);
 216                 if (ext->oe_fsync_wait && !ext->oe_urgent && !ext->oe_hp)
 217                         GOTO(out, rc = 65);
 218         default:
 219                 if (atomic_read(&ext->oe_users) > 0)
 220                         GOTO(out, rc = 70);
 221         }
 222
 223         if (ext->oe_max_end < ext->oe_end || ext->oe_end < ext->oe_start)
 224                 GOTO(out, rc = 80);
 225
 226         if (ext->oe_sync && ext->oe_grants > 0)
 227                 GOTO(out, rc = 90);
 228
 229         if (ext->oe_dlmlock != NULL && !ldlm_is_failed(ext->oe_dlmlock)) {
 230                 struct ldlm_extent *extent;
 231
 232                 extent = &ext->oe_dlmlock->l_policy_data.l_extent;
 233                 if (!(extent->start <= cl_offset(osc2cl(obj), ext->oe_start) &&
 234                       extent->end   >= cl_offset(osc2cl(obj), ext->oe_max_end)))
 235                         GOTO(out, rc = 100);
 236
 237                 if (!(ext->oe_dlmlock->l_granted_mode & (LCK_PW | LCK_GROUP)))
 238                         GOTO(out, rc = 102);
 239         }
 240
 241         if (ext->oe_nr_pages > ext->oe_mppr)
 242                 GOTO(out, rc = 105);
 243
 244         /* Do not verify page list if extent is in RPC. This is because an
 245          * in-RPC extent is supposed to be exclusively accessible w/o lock. */
 246         if (ext->oe_state > OES_CACHE)
 247                 GOTO(out, rc = 0);
 248
 249         if (!extent_debug)
 250                 GOTO(out, rc = 0);
 251
 252         page_count = 0;
 253         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
 254                 pgoff_t index = osc_index(oap2osc(oap));
 255                 ++page_count;
 256                 if (index > ext->oe_end || index < ext->oe_start)
 257                         GOTO(out, rc = 110);
 258         }
 259         if (page_count != ext->oe_nr_pages)
 260                 GOTO(out, rc = 120);
 261
 262 out:
 263         if (rc != 0)
 264                 OSC_EXTENT_DUMP(D_ERROR, ext,
 265                                 "%s:%d sanity check %p failed with rc = %d\n",
 266                                 func, line, ext, rc);
 267         return rc;
 268 }
 269
 270 #define sanity_check_nolock(ext) \
 271         osc_extent_sanity_check0(ext, __func__, __LINE__)
 272
 273 #define sanity_check(ext) ({                                                   \
 274         int __res;                                                             \
 275         osc_object_lock((ext)->oe_obj);                                        \
 276         __res = sanity_check_nolock(ext);                                      \
 277         osc_object_unlock((ext)->oe_obj);                                      \
 278         __res;                                                                 \
 279 })
 280
 281
 282 /**
 283  * sanity check - to make sure there is no overlapped extent in the tree.
 284  */
 285 static int osc_extent_is_overlapped(struct osc_object *obj,
 286                                     struct osc_extent *ext)
 287 {
 288         struct osc_extent *tmp;
 289
 290         LASSERT(osc_object_is_locked(obj));
 291
 292         if (!extent_debug)
 293                 return 0;
 294
 295         for (tmp = first_extent(obj); tmp != NULL; tmp = next_extent(tmp)) {
 296                 if (tmp == ext)
 297                         continue;
 298                 if (tmp->oe_end >= ext->oe_start &&
 299                     tmp->oe_start <= ext->oe_end)
 300                         return 1;
 301         }
 302         return 0;
 303 }
 304
 305 static void osc_extent_state_set(struct osc_extent *ext, int state)
 306 {
 307         LASSERT(osc_object_is_locked(ext->oe_obj));
 308         LASSERT(state >= OES_INV && state < OES_STATE_MAX);
 309
 310         /* Never try to sanity check a state changing extent :-) */
 311         /* LASSERT(sanity_check_nolock(ext) == 0); */
 312
 313         /* TODO: validate the state machine */
 314         ext->oe_state = state;
 315         wake_up_all(&ext->oe_waitq);
 316 }
 317
 318 static struct osc_extent *osc_extent_alloc(struct osc_object *obj)
 319 {
 320         struct osc_extent *ext;
 321
 322         OBD_SLAB_ALLOC_PTR_GFP(ext, osc_extent_kmem, GFP_IOFS);
 323         if (ext == NULL)
 324                 return NULL;
 325
 326         RB_CLEAR_NODE(&ext->oe_node);
 327         ext->oe_obj = obj;
 328         cl_object_get(osc2cl(obj));
 329         atomic_set(&ext->oe_refc, 1);
 330         atomic_set(&ext->oe_users, 0);
 331         INIT_LIST_HEAD(&ext->oe_link);
 332         ext->oe_state = OES_INV;
 333         INIT_LIST_HEAD(&ext->oe_pages);
 334         init_waitqueue_head(&ext->oe_waitq);
 335         ext->oe_dlmlock = NULL;
 336
 337         return ext;
 338 }
 339
 340 static void osc_extent_free(struct osc_extent *ext)
 341 {
 342         OBD_SLAB_FREE_PTR(ext, osc_extent_kmem);
 343 }
 344
 345 static struct osc_extent *osc_extent_get(struct osc_extent *ext)
 346 {
 347         LASSERT(atomic_read(&ext->oe_refc) >= 0);
 348         atomic_inc(&ext->oe_refc);
 349         return ext;
 350 }
 351
 352 static void osc_extent_put(const struct lu_env *env, struct osc_extent *ext)
 353 {
 354         LASSERT(atomic_read(&ext->oe_refc) > 0);
 355         if (atomic_dec_and_test(&ext->oe_refc)) {
 356                 LASSERT(list_empty(&ext->oe_link));
 357                 LASSERT(atomic_read(&ext->oe_users) == 0);
 358                 LASSERT(ext->oe_state == OES_INV);
 359                 LASSERT(!ext->oe_intree);
 360
 361                 if (ext->oe_dlmlock != NULL) {
 362                         lu_ref_add(&ext->oe_dlmlock->l_reference,
 363                                    "osc_extent", ext);
 364                         LDLM_LOCK_PUT(ext->oe_dlmlock);
 365                         ext->oe_dlmlock = NULL;
 366                 }
 367                 cl_object_put(env, osc2cl(ext->oe_obj));
 368                 osc_extent_free(ext);
 369         }
 370 }
 371
 372 /**
 373  * osc_extent_put_trust() is a special version of osc_extent_put() when
 374  * it's known that the caller is not the last user. This is to address the
 375  * problem of lacking of lu_env ;-).
 376  */
 377 static void osc_extent_put_trust(struct osc_extent *ext)
 378 {
 379         LASSERT(atomic_read(&ext->oe_refc) > 1);
 380         LASSERT(osc_object_is_locked(ext->oe_obj));
 381         atomic_dec(&ext->oe_refc);
 382 }
 383
 384 /**
 385  * Return the extent which includes pgoff @index, or return the greatest
 386  * previous extent in the tree.
 387  */
 388 static struct osc_extent *osc_extent_search(struct osc_object *obj,
 389                                             pgoff_t index)
 390 {
 391         struct rb_node    *n = obj->oo_root.rb_node;
 392         struct osc_extent *tmp, *p = NULL;
 393
 394         LASSERT(osc_object_is_locked(obj));
 395         while (n != NULL) {
 396                 tmp = rb_extent(n);
 397                 if (index < tmp->oe_start) {
 398                         n = n->rb_left;
 399                 } else if (index > tmp->oe_end) {
 400                         p = rb_extent(n);
 401                         n = n->rb_right;
 402                 } else {
 403                         return tmp;
 404                 }
 405         }
 406         return p;
 407 }
 408
 409 /*
 410  * Return the extent covering @index, otherwise return NULL.
 411  * caller must have held object lock.
 412  */
 413 static struct osc_extent *osc_extent_lookup(struct osc_object *obj,
 414                                             pgoff_t index)
 415 {
 416         struct osc_extent *ext;
 417
 418         ext = osc_extent_search(obj, index);
 419         if (ext != NULL && ext->oe_start <= index && index <= ext->oe_end)
 420                 return osc_extent_get(ext);
 421         return NULL;
 422 }
 423
 424 /* caller must have held object lock. */
 425 static void osc_extent_insert(struct osc_object *obj, struct osc_extent *ext)
 426 {
 427         struct rb_node   **n      = &obj->oo_root.rb_node;
 428         struct rb_node    *parent = NULL;
 429         struct osc_extent *tmp;
 430
 431         LASSERT(ext->oe_intree == 0);
 432         LASSERT(ext->oe_obj == obj);
 433         LASSERT(osc_object_is_locked(obj));
 434         while (*n != NULL) {
 435                 tmp = rb_extent(*n);
 436                 parent = *n;
 437
 438                 if (ext->oe_end < tmp->oe_start)
 439                         n = &(*n)->rb_left;
 440                 else if (ext->oe_start > tmp->oe_end)
 441                         n = &(*n)->rb_right;
 442                 else
 443                         EASSERTF(0, tmp, EXTSTR"\n", EXTPARA(ext));
 444         }
 445         rb_link_node(&ext->oe_node, parent, n);
 446         rb_insert_color(&ext->oe_node, &obj->oo_root);
 447         osc_extent_get(ext);
 448         ext->oe_intree = 1;
 449 }
 450
 451 /* caller must have held object lock. */
 452 static void osc_extent_erase(struct osc_extent *ext)
 453 {
 454         struct osc_object *obj = ext->oe_obj;
 455         LASSERT(osc_object_is_locked(obj));
 456         if (ext->oe_intree) {
 457                 rb_erase(&ext->oe_node, &obj->oo_root);
 458                 ext->oe_intree = 0;
 459                 /* rbtree held a refcount */
 460                 osc_extent_put_trust(ext);
 461         }
 462 }
 463
 464 static struct osc_extent *osc_extent_hold(struct osc_extent *ext)
 465 {
 466         struct osc_object *obj = ext->oe_obj;
 467
 468         LASSERT(osc_object_is_locked(obj));
 469         LASSERT(ext->oe_state == OES_ACTIVE || ext->oe_state == OES_CACHE);
 470         if (ext->oe_state == OES_CACHE) {
 471                 osc_extent_state_set(ext, OES_ACTIVE);
 472                 osc_update_pending(obj, OBD_BRW_WRITE, -ext->oe_nr_pages);
 473         }
 474         atomic_inc(&ext->oe_users);
 475         list_del_init(&ext->oe_link);
 476         return osc_extent_get(ext);
 477 }
 478
 479 static void __osc_extent_remove(struct osc_extent *ext)
 480 {
 481         LASSERT(osc_object_is_locked(ext->oe_obj));
 482         LASSERT(list_empty(&ext->oe_pages));
 483         osc_extent_erase(ext);
 484         list_del_init(&ext->oe_link);
 485         osc_extent_state_set(ext, OES_INV);
 486         OSC_EXTENT_DUMP(D_CACHE, ext, "destroyed.\n");
 487 }
 488
 489 static void osc_extent_remove(struct osc_extent *ext)
 490 {
 491         struct osc_object *obj = ext->oe_obj;
 492
 493         osc_object_lock(obj);
 494         __osc_extent_remove(ext);
 495         osc_object_unlock(obj);
 496 }
 497
 498 /**
 499  * This function is used to merge extents to get better performance. It checks
 500  * if @cur and @victim are contiguous at chunk level.
 501  */
 502 static int osc_extent_merge(const struct lu_env *env, struct osc_extent *cur,
 503                             struct osc_extent *victim)
 504 {
 505         struct osc_object *obj = cur->oe_obj;
 506         pgoff_t chunk_start;
 507         pgoff_t chunk_end;
 508         int ppc_bits;
 509
 510         LASSERT(cur->oe_state == OES_CACHE);
 511         LASSERT(osc_object_is_locked(obj));
 512         if (victim == NULL)
 513                 return -EINVAL;
 514
 515         if (victim->oe_state != OES_CACHE || victim->oe_fsync_wait)
 516                 return -EBUSY;
 517
 518         if (cur->oe_max_end != victim->oe_max_end)
 519                 return -ERANGE;
 520
 521         LASSERT(cur->oe_dlmlock == victim->oe_dlmlock);
 522         ppc_bits = osc_cli(obj)->cl_chunkbits - PAGE_CACHE_SHIFT;
 523         chunk_start = cur->oe_start >> ppc_bits;
 524         chunk_end   = cur->oe_end   >> ppc_bits;
 525         if (chunk_start   != (victim->oe_end >> ppc_bits) + 1 &&
 526             chunk_end + 1 != victim->oe_start >> ppc_bits)
 527                 return -ERANGE;
 528
 529         OSC_EXTENT_DUMP(D_CACHE, victim, "will be merged by %p.\n", cur);
 530
 531         cur->oe_start     = min(cur->oe_start, victim->oe_start);
 532         cur->oe_end       = max(cur->oe_end,   victim->oe_end);
 533         cur->oe_grants   += victim->oe_grants;
 534         cur->oe_nr_pages += victim->oe_nr_pages;
 535         /* only the following bits are needed to merge */
 536         cur->oe_urgent   |= victim->oe_urgent;
 537         cur->oe_memalloc |= victim->oe_memalloc;
 538         list_splice_init(&victim->oe_pages, &cur->oe_pages);
 539         list_del_init(&victim->oe_link);
 540         victim->oe_nr_pages = 0;
 541
 542         osc_extent_get(victim);
 543         __osc_extent_remove(victim);
 544         osc_extent_put(env, victim);
 545
 546         OSC_EXTENT_DUMP(D_CACHE, cur, "after merging %p.\n", victim);
 547         return 0;
 548 }
 549
 550 /**
 551  * Drop user count of osc_extent, and unplug IO asynchronously.
 552  */
 553 int osc_extent_release(const struct lu_env *env, struct osc_extent *ext)
 554 {
 555         struct osc_object *obj = ext->oe_obj;
 556         int rc = 0;
 557         ENTRY;
 558
 559         LASSERT(atomic_read(&ext->oe_users) > 0);
 560         LASSERT(sanity_check(ext) == 0);
 561         LASSERT(ext->oe_grants > 0);
 562
 563         if (atomic_dec_and_lock(&ext->oe_users, &obj->oo_lock)) {
 564                 LASSERT(ext->oe_state == OES_ACTIVE);
 565                 if (ext->oe_trunc_pending) {
 566                         /* a truncate process is waiting for this extent.
 567                          * This may happen due to a race, check
 568                          * osc_cache_truncate_start(). */
 569                         osc_extent_state_set(ext, OES_TRUNC);
 570                         ext->oe_trunc_pending = 0;
 571                 } else {
 572                         osc_extent_state_set(ext, OES_CACHE);
 573                         osc_update_pending(obj, OBD_BRW_WRITE,
 574                                            ext->oe_nr_pages);
 575
 576                         /* try to merge the previous and next extent. */
 577                         osc_extent_merge(env, ext, prev_extent(ext));
 578                         osc_extent_merge(env, ext, next_extent(ext));
 579
 580                         if (ext->oe_urgent)
 581                                 list_move_tail(&ext->oe_link,
 582                                                &obj->oo_urgent_exts);
 583                 }
 584                 osc_object_unlock(obj);
 585
 586                 osc_io_unplug_async(env, osc_cli(obj), obj);
 587         }
 588         osc_extent_put(env, ext);
 589         RETURN(rc);
 590 }
 591
 592 static inline int overlapped(struct osc_extent *ex1, struct osc_extent *ex2)
 593 {
 594         return !(ex1->oe_end < ex2->oe_start || ex2->oe_end < ex1->oe_start);
 595 }
 596
 597 /**
 598  * Find or create an extent which includes @index, core function to manage
 599  * extent tree.
 600  */
 601 static struct osc_extent *osc_extent_find(const struct lu_env *env,
 602                                           struct osc_object *obj, pgoff_t index,
 603                                           unsigned int *grants)
 604 {
 605         struct client_obd *cli = osc_cli(obj);
 606         struct osc_lock   *olck;
 607         struct cl_lock_descr *descr;
 608         struct osc_extent *cur;
 609         struct osc_extent *ext;
 610         struct osc_extent *conflict = NULL;
 611         struct osc_extent *found = NULL;
 612         pgoff_t    chunk;
 613         pgoff_t    max_end;
 614         unsigned int max_pages; /* max_pages_per_rpc */
 615         unsigned int chunksize;
 616         int        ppc_bits; /* pages per chunk bits */
 617         pgoff_t    chunk_mask;
 618         int        rc;
 619         ENTRY;
 620
 621         cur = osc_extent_alloc(obj);
 622         if (cur == NULL)
 623                 RETURN(ERR_PTR(-ENOMEM));
 624
 625         olck = osc_env_io(env)->oi_write_osclock;
 626         LASSERTF(olck != NULL, "page %lu is not covered by lock\n", index);
 627         LASSERT(olck->ols_state == OLS_GRANTED);
 628
 629         descr = &olck->ols_cl.cls_lock->cll_descr;
 630         LASSERT(descr->cld_mode >= CLM_WRITE);
 631
 632         LASSERT(cli->cl_chunkbits >= PAGE_CACHE_SHIFT);
 633         ppc_bits   = cli->cl_chunkbits - PAGE_CACHE_SHIFT;
 634         chunk_mask = ~((1 << ppc_bits) - 1);
 635         chunksize  = 1 << cli->cl_chunkbits;
 636         chunk      = index >> ppc_bits;
 637
 638         /* align end to rpc edge, rpc size may not be a power 2 integer. */
 639         max_pages = cli->cl_max_pages_per_rpc;
 640         LASSERT((max_pages & ~chunk_mask) == 0);
 641         max_end = index - (index % max_pages) + max_pages - 1;
 642         max_end = min_t(pgoff_t, max_end, descr->cld_end);
 643
 644         /* initialize new extent by parameters so far */
 645         cur->oe_max_end = max_end;
 646         cur->oe_start   = index & chunk_mask;
 647         cur->oe_end     = ((index + ~chunk_mask + 1) & chunk_mask) - 1;
 648         if (cur->oe_start < descr->cld_start)
 649                 cur->oe_start = descr->cld_start;
 650         if (cur->oe_end > max_end)
 651                 cur->oe_end = max_end;
 652         cur->oe_grants  = 0;
 653         cur->oe_mppr    = max_pages;
 654         if (olck->ols_dlmlock != NULL) {
 655                 LASSERT(olck->ols_hold);
 656                 cur->oe_dlmlock = LDLM_LOCK_GET(olck->ols_dlmlock);
 657                 lu_ref_add(&olck->ols_dlmlock->l_reference, "osc_extent", cur);
 658         }
 659
 660         /* grants has been allocated by caller */
 661         LASSERTF(*grants >= chunksize + cli->cl_extent_tax,
 662                  "%u/%u/%u.\n", *grants, chunksize, cli->cl_extent_tax);
 663         LASSERTF((max_end - cur->oe_start) < max_pages, EXTSTR"\n",
 664                  EXTPARA(cur));
 665
 666 restart:
 667         osc_object_lock(obj);
 668         ext = osc_extent_search(obj, cur->oe_start);
 669         if (ext == NULL)
 670                 ext = first_extent(obj);
 671         while (ext != NULL) {
 672                 pgoff_t ext_chk_start = ext->oe_start >> ppc_bits;
 673                 pgoff_t ext_chk_end   = ext->oe_end   >> ppc_bits;
 674
 675                 LASSERT(sanity_check_nolock(ext) == 0);
 676                 if (chunk > ext_chk_end + 1)
 677                         break;
 678
 679                 /* if covering by different locks, no chance to match */
 680                 if (olck->ols_dlmlock != ext->oe_dlmlock) {
 681                         EASSERTF(!overlapped(ext, cur), ext,
 682                                  EXTSTR"\n", EXTPARA(cur));
 683
 684                         ext = next_extent(ext);
 685                         continue;
 686                 }
 687
 688                 /* discontiguous chunks? */
 689                 if (chunk + 1 < ext_chk_start) {
 690                         ext = next_extent(ext);
 691                         continue;
 692                 }
 693
 694                 /* ok, from now on, ext and cur have these attrs:
 695                  * 1. covered by the same lock
 696                  * 2. contiguous at chunk level or overlapping. */
 697
 698                 if (overlapped(ext, cur)) {
 699                         /* cur is the minimum unit, so overlapping means
 700                          * full contain. */
 701                         EASSERTF((ext->oe_start <= cur->oe_start &&
 702                                   ext->oe_end >= cur->oe_end),
 703                                  ext, EXTSTR"\n", EXTPARA(cur));
 704
 705                         if (ext->oe_state > OES_CACHE || ext->oe_fsync_wait) {
 706                                 /* for simplicity, we wait for this extent to
 707                                  * finish before going forward. */
 708                                 conflict = osc_extent_get(ext);
 709                                 break;
 710                         }
 711
 712                         found = osc_extent_hold(ext);
 713                         break;
 714                 }
 715
 716                 /* non-overlapped extent */
 717                 if (ext->oe_state != OES_CACHE || ext->oe_fsync_wait) {
 718                         /* we can't do anything for a non OES_CACHE extent, or
 719                          * if there is someone waiting for this extent to be
 720                          * flushed, try next one. */
 721                         ext = next_extent(ext);
 722                         continue;
 723                 }
 724
 725                 /* check if they belong to the same rpc slot before trying to
 726                  * merge. the extents are not overlapped and contiguous at
 727                  * chunk level to get here. */
 728                 if (ext->oe_max_end != max_end) {
 729                         /* if they don't belong to the same RPC slot or
 730                          * max_pages_per_rpc has ever changed, do not merge. */
 731                         ext = next_extent(ext);
 732                         continue;
 733                 }
 734
 735                 /* it's required that an extent must be contiguous at chunk
 736                  * level so that we know the whole extent is covered by grant
 737                  * (the pages in the extent are NOT required to be contiguous).
 738                  * Otherwise, it will be too much difficult to know which
 739                  * chunks have grants allocated. */
 740
 741                 /* try to do front merge - extend ext's start */
 742                 if (chunk + 1 == ext_chk_start) {
 743                         /* ext must be chunk size aligned */
 744                         EASSERT((ext->oe_start & ~chunk_mask) == 0, ext);
 745
 746                         /* pull ext's start back to cover cur */
 747                         ext->oe_start   = cur->oe_start;
 748                         ext->oe_grants += chunksize;
 749                         *grants -= chunksize;
 750
 751                         found = osc_extent_hold(ext);
 752                 } else if (chunk == ext_chk_end + 1) {
 753                         /* rear merge */
 754                         ext->oe_end     = cur->oe_end;
 755                         ext->oe_grants += chunksize;
 756                         *grants -= chunksize;
 757
 758                         /* try to merge with the next one because we just fill
 759                          * in a gap */
 760                         if (osc_extent_merge(env, ext, next_extent(ext)) == 0)
 761                                 /* we can save extent tax from next extent */
 762                                 *grants += cli->cl_extent_tax;
 763
 764                         found = osc_extent_hold(ext);
 765                 }
 766                 if (found != NULL)
 767                         break;
 768
 769                 ext = next_extent(ext);
 770         }
 771
 772         osc_extent_tree_dump(D_CACHE, obj);
 773         if (found != NULL) {
 774                 LASSERT(conflict == NULL);
 775                 if (!IS_ERR(found)) {
 776                         LASSERT(found->oe_dlmlock == cur->oe_dlmlock);
 777                         OSC_EXTENT_DUMP(D_CACHE, found,
 778                                         "found caching ext for %lu.\n", index);
 779                 }
 780         } else if (conflict == NULL) {
 781                 /* create a new extent */
 782                 EASSERT(osc_extent_is_overlapped(obj, cur) == 0, cur);
 783                 cur->oe_grants = chunksize + cli->cl_extent_tax;
 784                 *grants -= cur->oe_grants;
 785                 LASSERT(*grants >= 0);
 786
 787                 cur->oe_state = OES_CACHE;
 788                 found = osc_extent_hold(cur);
 789                 osc_extent_insert(obj, cur);
 790                 OSC_EXTENT_DUMP(D_CACHE, cur, "add into tree %lu/%lu.\n",
 791                                 index, descr->cld_end);
 792         }
 793         osc_object_unlock(obj);
 794
 795         if (conflict != NULL) {
 796                 LASSERT(found == NULL);
 797
 798                 /* waiting for IO to finish. Please notice that it's impossible
 799                  * to be an OES_TRUNC extent. */
 800                 rc = osc_extent_wait(env, conflict, OES_INV);
 801                 osc_extent_put(env, conflict);
 802                 conflict = NULL;
 803                 if (rc < 0)
 804                         GOTO(out, found = ERR_PTR(rc));
 805
 806                 goto restart;
 807         }
 808         EXIT;
 809
 810 out:
 811         osc_extent_put(env, cur);
 812         LASSERT(*grants >= 0);
 813         return found;
 814 }
 815
 816 /**
 817  * Called when IO is finished to an extent.
 818  */
 819 int osc_extent_finish(const struct lu_env *env, struct osc_extent *ext,
 820                       int sent, int rc)
 821 {
 822         struct client_obd *cli = osc_cli(ext->oe_obj);
 823         struct osc_async_page *oap;
 824         struct osc_async_page *tmp;
 825         int nr_pages = ext->oe_nr_pages;
 826         int lost_grant = 0;
 827         int blocksize = cli->cl_import->imp_obd->obd_osfs.os_bsize ? : 4096;
 828         loff_t last_off = 0;
 829         int last_count = -1;
 830         ENTRY;
 831
 832         OSC_EXTENT_DUMP(D_CACHE, ext, "extent finished.\n");
 833
 834         ext->oe_rc = rc ?: ext->oe_nr_pages;
 835         EASSERT(ergo(rc == 0, ext->oe_state == OES_RPC), ext);
 836
 837         osc_lru_add_batch(cli, &ext->oe_pages);
 838         list_for_each_entry_safe(oap, tmp, &ext->oe_pages,
 839                                      oap_pending_item) {
 840                 list_del_init(&oap->oap_rpc_item);
 841                 list_del_init(&oap->oap_pending_item);
 842                 if (last_off <= oap->oap_obj_off) {
 843                         last_off = oap->oap_obj_off;
 844                         last_count = oap->oap_count;
 845                 }
 846
 847                 --ext->oe_nr_pages;
 848                 osc_ap_completion(env, cli, oap, sent, rc);
 849         }
 850         EASSERT(ext->oe_nr_pages == 0, ext);
 851
 852         if (!sent) {
 853                 lost_grant = ext->oe_grants;
 854         } else if (blocksize < PAGE_CACHE_SIZE &&
 855                    last_count != PAGE_CACHE_SIZE) {
 856                 /* For short writes we shouldn't count parts of pages that
 857                  * span a whole chunk on the OST side, or our accounting goes
 858                  * wrong.  Should match the code in filter_grant_check. */
 859                 int offset = last_off & ~PAGE_MASK;
 860                 int count = last_count + (offset & (blocksize - 1));
 861                 int end = (offset + last_count) & (blocksize - 1);
 862                 if (end)
 863                         count += blocksize - end;
 864
 865                 lost_grant = PAGE_CACHE_SIZE - count;
 866         }
 867         if (ext->oe_grants > 0)
 868                 osc_free_grant(cli, nr_pages, lost_grant);
 869
 870         osc_extent_remove(ext);
 871         /* put the refcount for RPC */
 872         osc_extent_put(env, ext);
 873         RETURN(0);
 874 }
 875
 876 static int extent_wait_cb(struct osc_extent *ext, enum osc_extent_state state)
 877 {
 878         int ret;
 879
 880         osc_object_lock(ext->oe_obj);
 881         ret = ext->oe_state == state;
 882         osc_object_unlock(ext->oe_obj);
 883
 884         return ret;
 885 }
 886
 887 /**
 888  * Wait for the extent's state to become @state.
 889  */
 890 static int osc_extent_wait(const struct lu_env *env, struct osc_extent *ext,
 891                            enum osc_extent_state state)
 892 {
 893         struct osc_object *obj = ext->oe_obj;
 894         struct l_wait_info lwi = LWI_TIMEOUT_INTR(cfs_time_seconds(600), NULL,
 895                                                   LWI_ON_SIGNAL_NOOP, NULL);
 896         int rc = 0;
 897         ENTRY;
 898
 899         osc_object_lock(obj);
 900         LASSERT(sanity_check_nolock(ext) == 0);
 901         /* `Kick' this extent only if the caller is waiting for it to be
 902          * written out. */
 903         if (state == OES_INV && !ext->oe_urgent && !ext->oe_hp) {
 904                 if (ext->oe_state == OES_ACTIVE) {
 905                         ext->oe_urgent = 1;
 906                 } else if (ext->oe_state == OES_CACHE) {
 907                         ext->oe_urgent = 1;
 908                         osc_extent_hold(ext);
 909                         rc = 1;
 910                 }
 911         }
 912         osc_object_unlock(obj);
 913         if (rc == 1)
 914                 osc_extent_release(env, ext);
 915
 916         /* wait for the extent until its state becomes @state */
 917         rc = l_wait_event(ext->oe_waitq, extent_wait_cb(ext, state), &lwi);
 918         if (rc == -ETIMEDOUT) {
 919                 OSC_EXTENT_DUMP(D_ERROR, ext,
 920                         "%s: wait ext to %u timedout, recovery in progress?\n",
 921                         cli_name(osc_cli(obj)), state);
 922
 923                 lwi = LWI_INTR(NULL, NULL);
 924                 rc = l_wait_event(ext->oe_waitq, extent_wait_cb(ext, state),
 925                                   &lwi);
 926         }
 927         if (rc == 0 && ext->oe_rc < 0)
 928                 rc = ext->oe_rc;
 929         RETURN(rc);
 930 }
 931
 932 /**
 933  * Discard pages with index greater than @size. If @ext is overlapped with
 934  * @size, then partial truncate happens.
 935  */
 936 static int osc_extent_truncate(struct osc_extent *ext, pgoff_t trunc_index,
 937                                 bool partial)
 938 {
 939         struct cl_env_nest     nest;
 940         struct lu_env         *env;
 941         struct cl_io          *io;
 942         struct osc_object     *obj = ext->oe_obj;
 943         struct client_obd     *cli = osc_cli(obj);
 944         struct osc_async_page *oap;
 945         struct osc_async_page *tmp;
 946         int                    pages_in_chunk = 0;
 947         int                    ppc_bits    = cli->cl_chunkbits -
 948                                              PAGE_CACHE_SHIFT;
 949         __u64                  trunc_chunk = trunc_index >> ppc_bits;
 950         int                    grants   = 0;
 951         int                    nr_pages = 0;
 952         int                    rc       = 0;
 953         ENTRY;
 954
 955         LASSERT(sanity_check(ext) == 0);
 956         LASSERT(ext->oe_state == OES_TRUNC);
 957         LASSERT(!ext->oe_urgent);
 958
 959         /* Request new lu_env.
 960          * We can't use that env from osc_cache_truncate_start() because
 961          * it's from lov_io_sub and not fully initialized. */
 962         env = cl_env_nested_get(&nest);
 963         io  = &osc_env_info(env)->oti_io;
 964         io->ci_obj = cl_object_top(osc2cl(obj));
 965         rc = cl_io_init(env, io, CIT_MISC, io->ci_obj);
 966         if (rc < 0)
 967                 GOTO(out, rc);
 968
 969         /* discard all pages with index greater than trunc_index */
 970         list_for_each_entry_safe(oap, tmp, &ext->oe_pages,
 971                                      oap_pending_item) {
 972                 pgoff_t index = osc_index(oap2osc(oap));
 973                 struct cl_page  *page = oap2cl_page(oap);
 974
 975                 LASSERT(list_empty(&oap->oap_rpc_item));
 976
 977                 /* only discard the pages with their index greater than
 978                  * trunc_index, and ... */
 979                 if (index < trunc_index ||
 980                     (index == trunc_index && partial)) {
 981                         /* accounting how many pages remaining in the chunk
 982                          * so that we can calculate grants correctly. */
 983                         if (index >> ppc_bits == trunc_chunk)
 984                                 ++pages_in_chunk;
 985                         continue;
 986                 }
 987
 988                 list_del_init(&oap->oap_pending_item);
 989
 990                 cl_page_get(page);
 991                 lu_ref_add(&page->cp_reference, "truncate", current);
 992
 993                 if (cl_page_own(env, io, page) == 0) {
 994                         cl_page_discard(env, io, page);
 995                         cl_page_disown(env, io, page);
 996                 } else {
 997                         LASSERT(page->cp_state == CPS_FREEING);
 998                         LASSERT(0);
 999                 }
1000
1001                 lu_ref_del(&page->cp_reference, "truncate", current);
1002                 cl_page_put(env, page);
1003
1004                 --ext->oe_nr_pages;
1005                 ++nr_pages;
1006         }
1007         EASSERTF(ergo(ext->oe_start >= trunc_index + !!partial,
1008                       ext->oe_nr_pages == 0),
1009                 ext, "trunc_index %lu, partial %d\n", trunc_index, partial);
1010
1011         osc_object_lock(obj);
1012         if (ext->oe_nr_pages == 0) {
1013                 LASSERT(pages_in_chunk == 0);
1014                 grants = ext->oe_grants;
1015                 ext->oe_grants = 0;
1016         } else { /* calculate how many grants we can free */
1017                 int     chunks = (ext->oe_end >> ppc_bits) - trunc_chunk;
1018                 pgoff_t last_index;
1019
1020
1021                 /* if there is no pages in this chunk, we can also free grants
1022                  * for the last chunk */
1023                 if (pages_in_chunk == 0) {
1024                         /* if this is the 1st chunk and no pages in this chunk,
1025                          * ext->oe_nr_pages must be zero, so we should be in
1026                          * the other if-clause. */
1027                         LASSERT(trunc_chunk > 0);
1028                         --trunc_chunk;
1029                         ++chunks;
1030                 }
1031
1032                 /* this is what we can free from this extent */
1033                 grants          = chunks << cli->cl_chunkbits;
1034                 ext->oe_grants -= grants;
1035                 last_index      = ((trunc_chunk + 1) << ppc_bits) - 1;
1036                 ext->oe_end     = min(last_index, ext->oe_max_end);
1037                 LASSERT(ext->oe_end >= ext->oe_start);
1038                 LASSERT(ext->oe_grants > 0);
1039         }
1040         osc_object_unlock(obj);
1041
1042         if (grants > 0 || nr_pages > 0)
1043                 osc_free_grant(cli, nr_pages, grants);
1044
1045 out:
1046         cl_io_fini(env, io);
1047         cl_env_nested_put(&nest, env);
1048         RETURN(rc);
1049 }
1050
1051 /**
1052  * This function is used to make the extent prepared for transfer.
1053  * A race with flusing page - ll_writepage() has to be handled cautiously.
1054  */
1055 static int osc_extent_make_ready(const struct lu_env *env,
1056                                  struct osc_extent *ext)
1057 {
1058         struct osc_async_page *oap;
1059         struct osc_async_page *last = NULL;
1060         struct osc_object *obj = ext->oe_obj;
1061         unsigned int page_count = 0;
1062         int rc;
1063         ENTRY;
1064
1065         /* we're going to grab page lock, so object lock must not be taken. */
1066         LASSERT(sanity_check(ext) == 0);
1067         /* in locking state, any process should not touch this extent. */
1068         EASSERT(ext->oe_state == OES_LOCKING, ext);
1069         EASSERT(ext->oe_owner != NULL, ext);
1070
1071         OSC_EXTENT_DUMP(D_CACHE, ext, "make ready\n");
1072
1073         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
1074                 ++page_count;
1075                 if (last == NULL || last->oap_obj_off < oap->oap_obj_off)
1076                         last = oap;
1077
1078                 /* checking ASYNC_READY is race safe */
1079                 if ((oap->oap_async_flags & ASYNC_READY) != 0)
1080                         continue;
1081
1082                 rc = osc_make_ready(env, oap, OBD_BRW_WRITE);
1083                 switch (rc) {
1084                 case 0:
1085                         spin_lock(&oap->oap_lock);
1086                         oap->oap_async_flags |= ASYNC_READY;
1087                         spin_unlock(&oap->oap_lock);
1088                         break;
1089                 case -EALREADY:
1090                         LASSERT((oap->oap_async_flags & ASYNC_READY) != 0);
1091                         break;
1092                 default:
1093                         LASSERTF(0, "unknown return code: %d\n", rc);
1094                 }
1095         }
1096
1097         LASSERT(page_count == ext->oe_nr_pages);
1098         LASSERT(last != NULL);
1099         /* the last page is the only one we need to refresh its count by
1100          * the size of file. */
1101         if (!(last->oap_async_flags & ASYNC_COUNT_STABLE)) {
1102                 int last_oap_count = osc_refresh_count(env, last, OBD_BRW_WRITE);
1103                 LASSERT(last_oap_count > 0);
1104                 LASSERT(last->oap_page_off + last_oap_count <= PAGE_CACHE_SIZE);
1105                 last->oap_count = last_oap_count;
1106                 spin_lock(&last->oap_lock);
1107                 last->oap_async_flags |= ASYNC_COUNT_STABLE;
1108                 spin_unlock(&last->oap_lock);
1109         }
1110
1111         /* for the rest of pages, we don't need to call osf_refresh_count()
1112          * because it's known they are not the last page */
1113         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
1114                 if (!(oap->oap_async_flags & ASYNC_COUNT_STABLE)) {
1115                         oap->oap_count = PAGE_CACHE_SIZE - oap->oap_page_off;
1116                         spin_lock(&oap->oap_lock);
1117                         oap->oap_async_flags |= ASYNC_COUNT_STABLE;
1118                         spin_unlock(&oap->oap_lock);
1119                 }
1120         }
1121
1122         osc_object_lock(obj);
1123         osc_extent_state_set(ext, OES_RPC);
1124         osc_object_unlock(obj);
1125         /* get a refcount for RPC. */
1126         osc_extent_get(ext);
1127
1128         RETURN(0);
1129 }
1130
1131 /**
1132  * Quick and simple version of osc_extent_find(). This function is frequently
1133  * called to expand the extent for the same IO. To expand the extent, the
1134  * page index must be in the same or next chunk of ext->oe_end.
1135  */
1136 static int osc_extent_expand(struct osc_extent *ext, pgoff_t index,
1137                              unsigned int *grants)
1138 {
1139         struct osc_object *obj = ext->oe_obj;
1140         struct client_obd *cli = osc_cli(obj);
1141         struct osc_extent *next;
1142         int ppc_bits = cli->cl_chunkbits - PAGE_CACHE_SHIFT;
1143         pgoff_t chunk = index >> ppc_bits;
1144         pgoff_t end_chunk;
1145         pgoff_t end_index;
1146         unsigned int chunksize = 1 << cli->cl_chunkbits;
1147         int rc = 0;
1148         ENTRY;
1149
1150         LASSERT(ext->oe_max_end >= index && ext->oe_start <= index);
1151         osc_object_lock(obj);
1152         LASSERT(sanity_check_nolock(ext) == 0);
1153         end_chunk = ext->oe_end >> ppc_bits;
1154         if (chunk > end_chunk + 1)
1155                 GOTO(out, rc = -ERANGE);
1156
1157         if (end_chunk >= chunk)
1158                 GOTO(out, rc = 0);
1159
1160         LASSERT(end_chunk + 1 == chunk);
1161         /* try to expand this extent to cover @index */
1162         end_index = min(ext->oe_max_end, ((chunk + 1) << ppc_bits) - 1);
1163
1164         next = next_extent(ext);
1165         if (next != NULL && next->oe_start <= end_index)
1166                 /* complex mode - overlapped with the next extent,
1167                  * this case will be handled by osc_extent_find() */
1168                 GOTO(out, rc = -EAGAIN);
1169
1170         ext->oe_end = end_index;
1171         ext->oe_grants += chunksize;
1172         *grants -= chunksize;
1173         LASSERT(*grants >= 0);
1174         EASSERTF(osc_extent_is_overlapped(obj, ext) == 0, ext,
1175                  "overlapped after expanding for %lu.\n", index);
1176         EXIT;
1177
1178 out:
1179         osc_object_unlock(obj);
1180         RETURN(rc);
1181 }
1182
1183 static void osc_extent_tree_dump0(int level, struct osc_object *obj,
1184                                   const char *func, int line)
1185 {
1186         struct osc_extent *ext;
1187         int cnt;
1188
1189         CDEBUG(level, "Dump object %p extents at %s:%d, mppr: %u.\n",
1190                obj, func, line, osc_cli(obj)->cl_max_pages_per_rpc);
1191
1192         /* osc_object_lock(obj); */
1193         cnt = 1;
1194         for (ext = first_extent(obj); ext != NULL; ext = next_extent(ext))
1195                 OSC_EXTENT_DUMP(level, ext, "in tree %d.\n", cnt++);
1196
1197         cnt = 1;
1198         list_for_each_entry(ext, &obj->oo_hp_exts, oe_link)
1199                 OSC_EXTENT_DUMP(level, ext, "hp %d.\n", cnt++);
1200
1201         cnt = 1;
1202         list_for_each_entry(ext, &obj->oo_urgent_exts, oe_link)
1203                 OSC_EXTENT_DUMP(level, ext, "urgent %d.\n", cnt++);
1204
1205         cnt = 1;
1206         list_for_each_entry(ext, &obj->oo_reading_exts, oe_link)
1207                 OSC_EXTENT_DUMP(level, ext, "reading %d.\n", cnt++);
1208         /* osc_object_unlock(obj); */
1209 }
1210
1211 /* ------------------ osc extent end ------------------ */
1212
1213 static inline int osc_is_ready(struct osc_object *osc)
1214 {
1215         return !list_empty(&osc->oo_ready_item) ||
1216                !list_empty(&osc->oo_hp_ready_item);
1217 }
1218
1219 #define OSC_IO_DEBUG(OSC, STR, args...)                                        \
1220         CDEBUG(D_CACHE, "obj %p ready %d|%c|%c wr %d|%c|%c rd %d|%c " STR,     \
1221                (OSC), osc_is_ready(OSC),                                       \
1222                list_empty_marker(&(OSC)->oo_hp_ready_item),                    \
1223                list_empty_marker(&(OSC)->oo_ready_item),                       \
1224                atomic_read(&(OSC)->oo_nr_writes),                              \
1225                list_empty_marker(&(OSC)->oo_hp_exts),                          \
1226                list_empty_marker(&(OSC)->oo_urgent_exts),                      \
1227                atomic_read(&(OSC)->oo_nr_reads),                               \
1228                list_empty_marker(&(OSC)->oo_reading_exts),                     \
1229                ##args)
1230
1231 static int osc_make_ready(const struct lu_env *env, struct osc_async_page *oap,
1232                           int cmd)
1233 {
1234         struct osc_page *opg  = oap2osc_page(oap);
1235         struct cl_page  *page = oap2cl_page(oap);
1236         int result;
1237
1238         LASSERT(cmd == OBD_BRW_WRITE); /* no cached reads */
1239
1240         ENTRY;
1241         result = cl_page_make_ready(env, page, CRT_WRITE);
1242         if (result == 0)
1243                 opg->ops_submit_time = cfs_time_current();
1244         RETURN(result);
1245 }
1246
1247 static int osc_refresh_count(const struct lu_env *env,
1248                              struct osc_async_page *oap, int cmd)
1249 {
1250         struct osc_page  *opg = oap2osc_page(oap);
1251         pgoff_t index = osc_index(oap2osc(oap));
1252         struct cl_object *obj;
1253         struct cl_attr   *attr = &osc_env_info(env)->oti_attr;
1254
1255         int result;
1256         loff_t kms;
1257
1258         /* readpage queues with _COUNT_STABLE, shouldn't get here. */
1259         LASSERT(!(cmd & OBD_BRW_READ));
1260         LASSERT(opg != NULL);
1261         obj = opg->ops_cl.cpl_obj;
1262
1263         cl_object_attr_lock(obj);
1264         result = cl_object_attr_get(env, obj, attr);
1265         cl_object_attr_unlock(obj);
1266         if (result < 0)
1267                 return result;
1268         kms = attr->cat_kms;
1269         if (cl_offset(obj, index) >= kms)
1270                 /* catch race with truncate */
1271                 return 0;
1272         else if (cl_offset(obj, index + 1) > kms)
1273                 /* catch sub-page write at end of file */
1274                 return kms % PAGE_CACHE_SIZE;
1275         else
1276                 return PAGE_CACHE_SIZE;
1277 }
1278
1279 static int osc_completion(const struct lu_env *env, struct osc_async_page *oap,
1280                           int cmd, int rc)
1281 {
1282         struct osc_page   *opg  = oap2osc_page(oap);
1283         struct cl_page    *page = oap2cl_page(oap);
1284         enum cl_req_type   crt;
1285         int srvlock;
1286
1287         ENTRY;
1288
1289         cmd &= ~OBD_BRW_NOQUOTA;
1290         LASSERTF(equi(page->cp_state == CPS_PAGEIN,  cmd == OBD_BRW_READ),
1291                  "cp_state:%u, cmd:%d\n", page->cp_state, cmd);
1292         LASSERTF(equi(page->cp_state == CPS_PAGEOUT, cmd == OBD_BRW_WRITE),
1293                 "cp_state:%u, cmd:%d\n", page->cp_state, cmd);
1294         LASSERT(opg->ops_transfer_pinned);
1295
1296         crt = cmd == OBD_BRW_READ ? CRT_READ : CRT_WRITE;
1297         /* Clear opg->ops_transfer_pinned before VM lock is released. */
1298         opg->ops_transfer_pinned = 0;
1299
1300         opg->ops_submit_time = 0;
1301         srvlock = oap->oap_brw_flags & OBD_BRW_SRVLOCK;
1302
1303         /* statistic */
1304         if (rc == 0 && srvlock) {
1305                 struct lu_device *ld    = opg->ops_cl.cpl_obj->co_lu.lo_dev;
1306                 struct osc_stats *stats = &lu2osc_dev(ld)->od_stats;
1307                 size_t bytes = oap->oap_count;
1308
1309                 if (crt == CRT_READ)
1310                         stats->os_lockless_reads += bytes;
1311                 else
1312                         stats->os_lockless_writes += bytes;
1313         }
1314
1315         /*
1316          * This has to be the last operation with the page, as locks are
1317          * released in cl_page_completion() and nothing except for the
1318          * reference counter protects page from concurrent reclaim.
1319          */
1320         lu_ref_del(&page->cp_reference, "transfer", page);
1321
1322         cl_page_completion(env, page, crt, rc);
1323         cl_page_put(env, page);
1324
1325         RETURN(0);
1326 }
1327
1328 #define OSC_DUMP_GRANT(lvl, cli, fmt, args...) do {                     \
1329         struct client_obd *__tmp = (cli);                               \
1330         CDEBUG(lvl, "%s: grant { dirty: %lu/%lu dirty_pages: %ld/%lu "  \
1331                "dropped: %ld avail: %ld, reserved: %ld, flight: %d }"   \
1332                "lru {in list: %ld, left: %ld, waiters: %d }"fmt"\n",    \
1333                cli_name(__tmp),                                         \
1334                __tmp->cl_dirty_pages, __tmp->cl_dirty_max_pages,        \
1335                atomic_long_read(&obd_dirty_pages), obd_max_dirty_pages, \
1336                __tmp->cl_lost_grant, __tmp->cl_avail_grant,             \
1337                __tmp->cl_reserved_grant, __tmp->cl_w_in_flight,         \
1338                atomic_long_read(&__tmp->cl_lru_in_list),                \
1339                atomic_long_read(&__tmp->cl_lru_busy),                   \
1340                atomic_read(&__tmp->cl_lru_shrinkers), ##args);          \
1341 } while (0)
1342
1343 /* caller must hold loi_list_lock */
1344 static void osc_consume_write_grant(struct client_obd *cli,
1345                                     struct brw_page *pga)
1346 {
1347         assert_spin_locked(&cli->cl_loi_list_lock);
1348         LASSERT(!(pga->flag & OBD_BRW_FROM_GRANT));
1349         atomic_long_inc(&obd_dirty_pages);
1350         cli->cl_dirty_pages++;
1351         pga->flag |= OBD_BRW_FROM_GRANT;
1352         CDEBUG(D_CACHE, "using %lu grant credits for brw %p page %p\n",
1353                PAGE_CACHE_SIZE, pga, pga->pg);
1354         osc_update_next_shrink(cli);
1355 }
1356
1357 /* the companion to osc_consume_write_grant, called when a brw has completed.
1358  * must be called with the loi lock held. */
1359 static void osc_release_write_grant(struct client_obd *cli,
1360                                     struct brw_page *pga)
1361 {
1362         ENTRY;
1363
1364         assert_spin_locked(&cli->cl_loi_list_lock);
1365         if (!(pga->flag & OBD_BRW_FROM_GRANT)) {
1366                 EXIT;
1367                 return;
1368         }
1369
1370         pga->flag &= ~OBD_BRW_FROM_GRANT;
1371         atomic_long_dec(&obd_dirty_pages);
1372         cli->cl_dirty_pages--;
1373         if (pga->flag & OBD_BRW_NOCACHE) {
1374                 pga->flag &= ~OBD_BRW_NOCACHE;
1375                 atomic_long_dec(&obd_dirty_transit_pages);
1376                 cli->cl_dirty_transit--;
1377         }
1378         EXIT;
1379 }
1380
1381 /**
1382  * To avoid sleeping with object lock held, it's good for us allocate enough
1383  * grants before entering into critical section.
1384  *
1385  * client_obd_list_lock held by caller
1386  */
1387 static int osc_reserve_grant(struct client_obd *cli, unsigned int bytes)
1388 {
1389         int rc = -EDQUOT;
1390
1391         if (cli->cl_avail_grant >= bytes) {
1392                 cli->cl_avail_grant    -= bytes;
1393                 cli->cl_reserved_grant += bytes;
1394                 rc = 0;
1395         }
1396         return rc;
1397 }
1398
1399 static void __osc_unreserve_grant(struct client_obd *cli,
1400                                   unsigned int reserved, unsigned int unused)
1401 {
1402         /* it's quite normal for us to get more grant than reserved.
1403          * Thinking about a case that two extents merged by adding a new
1404          * chunk, we can save one extent tax. If extent tax is greater than
1405          * one chunk, we can save more grant by adding a new chunk */
1406         cli->cl_reserved_grant -= reserved;
1407         if (unused > reserved) {
1408                 cli->cl_avail_grant += reserved;
1409                 cli->cl_lost_grant  += unused - reserved;
1410         } else {
1411                 cli->cl_avail_grant += unused;
1412         }
1413 }
1414
1415 static void osc_unreserve_grant(struct client_obd *cli,
1416                                 unsigned int reserved, unsigned int unused)
1417 {
1418         spin_lock(&cli->cl_loi_list_lock);
1419         __osc_unreserve_grant(cli, reserved, unused);
1420         if (unused > 0)
1421                 osc_wake_cache_waiters(cli);
1422         spin_unlock(&cli->cl_loi_list_lock);
1423 }
1424
1425 /**
1426  * Free grant after IO is finished or canceled.
1427  *
1428  * @lost_grant is used to remember how many grants we have allocated but not
1429  * used, we should return these grants to OST. There're two cases where grants
1430  * can be lost:
1431  * 1. truncate;
1432  * 2. blocksize at OST is less than PAGE_CACHE_SIZE and a partial page was
1433  *    written. In this case OST may use less chunks to serve this partial
1434  *    write. OSTs don't actually know the page size on the client side. so
1435  *    clients have to calculate lost grant by the blocksize on the OST.
1436  *    See filter_grant_check() for details.
1437  */
1438 static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
1439                            unsigned int lost_grant)
1440 {
1441         unsigned long grant = (1 << cli->cl_chunkbits) + cli->cl_extent_tax;
1442
1443         spin_lock(&cli->cl_loi_list_lock);
1444         atomic_long_sub(nr_pages, &obd_dirty_pages);
1445         cli->cl_dirty_pages -= nr_pages;
1446         cli->cl_lost_grant += lost_grant;
1447         if (cli->cl_avail_grant < grant && cli->cl_lost_grant >= grant) {
1448                 /* borrow some grant from truncate to avoid the case that
1449                  * truncate uses up all avail grant */
1450                 cli->cl_lost_grant -= grant;
1451                 cli->cl_avail_grant += grant;
1452         }
1453         osc_wake_cache_waiters(cli);
1454         spin_unlock(&cli->cl_loi_list_lock);
1455         CDEBUG(D_CACHE, "lost %u grant: %lu avail: %lu dirty: %lu\n",
1456                lost_grant, cli->cl_lost_grant,
1457                cli->cl_avail_grant, cli->cl_dirty_pages << PAGE_CACHE_SHIFT);
1458 }
1459
1460 /**
1461  * The companion to osc_enter_cache(), called when @oap is no longer part of
1462  * the dirty accounting due to error.
1463  */
1464 static void osc_exit_cache(struct client_obd *cli, struct osc_async_page *oap)
1465 {
1466         spin_lock(&cli->cl_loi_list_lock);
1467         osc_release_write_grant(cli, &oap->oap_brw_page);
1468         spin_unlock(&cli->cl_loi_list_lock);
1469 }
1470
1471 /**
1472  * Non-blocking version of osc_enter_cache() that consumes grant only when it
1473  * is available.
1474  */
1475 static int osc_enter_cache_try(struct client_obd *cli,
1476                                struct osc_async_page *oap,
1477                                int bytes, int transient)
1478 {
1479         int rc;
1480
1481         OSC_DUMP_GRANT(D_CACHE, cli, "need:%d\n", bytes);
1482
1483         rc = osc_reserve_grant(cli, bytes);
1484         if (rc < 0)
1485                 return 0;
1486
1487         if (cli->cl_dirty_pages < cli->cl_dirty_max_pages &&
1488             1 + atomic_long_read(&obd_dirty_pages) <= obd_max_dirty_pages) {
1489                 osc_consume_write_grant(cli, &oap->oap_brw_page);
1490                 if (transient) {
1491                         cli->cl_dirty_transit++;
1492                         atomic_long_inc(&obd_dirty_transit_pages);
1493                         oap->oap_brw_flags |= OBD_BRW_NOCACHE;
1494                 }
1495                 rc = 1;
1496         } else {
1497                 __osc_unreserve_grant(cli, bytes, bytes);
1498                 rc = 0;
1499         }
1500         return rc;
1501 }
1502
1503 static int ocw_granted(struct client_obd *cli, struct osc_cache_waiter *ocw)
1504 {
1505         int rc;
1506         spin_lock(&cli->cl_loi_list_lock);
1507         rc = list_empty(&ocw->ocw_entry);
1508         spin_unlock(&cli->cl_loi_list_lock);
1509         return rc;
1510 }
1511
1512 /**
1513  * The main entry to reserve dirty page accounting. Usually the grant reserved
1514  * in this function will be freed in bulk in osc_free_grant() unless it fails
1515  * to add osc cache, in that case, it will be freed in osc_exit_cache().
1516  *
1517  * The process will be put into sleep if it's already run out of grant.
1518  */
1519 static int osc_enter_cache(const struct lu_env *env, struct client_obd *cli,
1520                            struct osc_async_page *oap, int bytes)
1521 {
1522         struct osc_object       *osc = oap->oap_obj;
1523         struct lov_oinfo        *loi = osc->oo_oinfo;
1524         struct osc_cache_waiter  ocw;
1525         struct l_wait_info       lwi;
1526         int                      rc = -EDQUOT;
1527         ENTRY;
1528
1529         lwi = LWI_TIMEOUT_INTR(cfs_time_seconds(AT_OFF ? obd_timeout : at_max),
1530                                NULL, LWI_ON_SIGNAL_NOOP, NULL);
1531
1532         OSC_DUMP_GRANT(D_CACHE, cli, "need:%d\n", bytes);
1533
1534         spin_lock(&cli->cl_loi_list_lock);
1535
1536         /* force the caller to try sync io.  this can jump the list
1537          * of queued writes and create a discontiguous rpc stream */
1538         if (OBD_FAIL_CHECK(OBD_FAIL_OSC_NO_GRANT) ||
1539             cli->cl_dirty_max_pages == 0 ||
1540             cli->cl_ar.ar_force_sync || loi->loi_ar.ar_force_sync) {
1541                 OSC_DUMP_GRANT(D_CACHE, cli, "forced sync i/o\n");
1542                 GOTO(out, rc = -EDQUOT);
1543         }
1544
1545         /* Hopefully normal case - cache space and write credits available */
1546         if (osc_enter_cache_try(cli, oap, bytes, 0)) {
1547                 OSC_DUMP_GRANT(D_CACHE, cli, "granted from cache\n");
1548                 GOTO(out, rc = 0);
1549         }
1550
1551         /* We can get here for two reasons: too many dirty pages in cache, or
1552          * run out of grants. In both cases we should write dirty pages out.
1553          * Adding a cache waiter will trigger urgent write-out no matter what
1554          * RPC size will be.
1555          * The exiting condition is no avail grants and no dirty pages caching,
1556          * that really means there is no space on the OST. */
1557         init_waitqueue_head(&ocw.ocw_waitq);
1558         ocw.ocw_oap   = oap;
1559         ocw.ocw_grant = bytes;
1560         while (cli->cl_dirty_pages > 0 || cli->cl_w_in_flight > 0) {
1561                 list_add_tail(&ocw.ocw_entry, &cli->cl_cache_waiters);
1562                 ocw.ocw_rc = 0;
1563                 spin_unlock(&cli->cl_loi_list_lock);
1564
1565                 osc_io_unplug_async(env, cli, NULL);
1566
1567                 CDEBUG(D_CACHE, "%s: sleeping for cache space @ %p for %p\n",
1568                        cli_name(cli), &ocw, oap);
1569
1570                 rc = l_wait_event(ocw.ocw_waitq, ocw_granted(cli, &ocw), &lwi);
1571
1572                 spin_lock(&cli->cl_loi_list_lock);
1573
1574                 if (rc < 0) {
1575                         /* l_wait_event is interrupted by signal or timed out */
1576                         list_del_init(&ocw.ocw_entry);
1577                         break;
1578                 }
1579                 LASSERT(list_empty(&ocw.ocw_entry));
1580                 rc = ocw.ocw_rc;
1581
1582                 if (rc != -EDQUOT)
1583                         break;
1584                 if (osc_enter_cache_try(cli, oap, bytes, 0)) {
1585                         rc = 0;
1586                         break;
1587                 }
1588         }
1589
1590         switch (rc) {
1591         case 0:
1592                 OSC_DUMP_GRANT(D_CACHE, cli, "finally got grant space\n");
1593                 break;
1594         case -ETIMEDOUT:
1595                 OSC_DUMP_GRANT(D_CACHE, cli,
1596                                "timeout, fall back to sync i/o\n");
1597                 osc_extent_tree_dump(D_CACHE, osc);
1598                 /* fall back to synchronous I/O */
1599                 rc = -EDQUOT;
1600                 break;
1601         case -EINTR:
1602                 /* Ensures restartability - LU-3581 */
1603                 OSC_DUMP_GRANT(D_CACHE, cli, "interrupted\n");
1604                 rc = -ERESTARTSYS;
1605                 break;
1606         case -EDQUOT:
1607                 OSC_DUMP_GRANT(D_CACHE, cli,
1608                                "no grant space, fall back to sync i/o\n");
1609                 break;
1610         default:
1611                 CDEBUG(D_CACHE, "%s: event for cache space @ %p never arrived "
1612                        "due to %d, fall back to sync i/o\n",
1613                        cli_name(cli), &ocw, rc);
1614                 break;
1615         }
1616         EXIT;
1617 out:
1618         spin_unlock(&cli->cl_loi_list_lock);
1619         RETURN(rc);
1620 }
1621
1622 /* caller must hold loi_list_lock */
1623 void osc_wake_cache_waiters(struct client_obd *cli)
1624 {
1625         struct list_head *l, *tmp;
1626         struct osc_cache_waiter *ocw;
1627
1628         ENTRY;
1629         list_for_each_safe(l, tmp, &cli->cl_cache_waiters) {
1630                 ocw = list_entry(l, struct osc_cache_waiter, ocw_entry);
1631                 list_del_init(&ocw->ocw_entry);
1632
1633                 ocw->ocw_rc = -EDQUOT;
1634                 /* we can't dirty more */
1635                 if ((cli->cl_dirty_pages  >= cli->cl_dirty_max_pages) ||
1636                     (1 + atomic_long_read(&obd_dirty_pages) >
1637                      obd_max_dirty_pages)) {
1638                         CDEBUG(D_CACHE, "no dirty room: dirty: %ld "
1639                                "osc max %ld, sys max %ld\n",
1640                                cli->cl_dirty_pages, cli->cl_dirty_max_pages,
1641                                obd_max_dirty_pages);
1642                         goto wakeup;
1643                 }
1644
1645                 if (osc_enter_cache_try(cli, ocw->ocw_oap, ocw->ocw_grant, 0))
1646                         ocw->ocw_rc = 0;
1647 wakeup:
1648                 CDEBUG(D_CACHE, "wake up %p for oap %p, avail grant %ld, %d\n",
1649                        ocw, ocw->ocw_oap, cli->cl_avail_grant, ocw->ocw_rc);
1650
1651                 wake_up(&ocw->ocw_waitq);
1652         }
1653
1654         EXIT;
1655 }
1656
1657 static int osc_max_rpc_in_flight(struct client_obd *cli, struct osc_object *osc)
1658 {
1659         int hprpc = !!list_empty(&osc->oo_hp_exts);
1660         return rpcs_in_flight(cli) >= cli->cl_max_rpcs_in_flight + hprpc;
1661 }
1662
1663 /* This maintains the lists of pending pages to read/write for a given object
1664  * (lop).  This is used by osc_check_rpcs->osc_next_obj() and osc_list_maint()
1665  * to quickly find objects that are ready to send an RPC. */
1666 static int osc_makes_rpc(struct client_obd *cli, struct osc_object *osc,
1667                          int cmd)
1668 {
1669         int invalid_import = 0;
1670         ENTRY;
1671
1672         /* if we have an invalid import we want to drain the queued pages
1673          * by forcing them through rpcs that immediately fail and complete
1674          * the pages.  recovery relies on this to empty the queued pages
1675          * before canceling the locks and evicting down the llite pages */
1676         if ((cli->cl_import == NULL || cli->cl_import->imp_invalid))
1677                 invalid_import = 1;
1678
1679         if (cmd & OBD_BRW_WRITE) {
1680                 if (atomic_read(&osc->oo_nr_writes) == 0)
1681                         RETURN(0);
1682                 if (invalid_import) {
1683                         CDEBUG(D_CACHE, "invalid import forcing RPC\n");
1684                         RETURN(1);
1685                 }
1686                 if (!list_empty(&osc->oo_hp_exts)) {
1687                         CDEBUG(D_CACHE, "high prio request forcing RPC\n");
1688                         RETURN(1);
1689                 }
1690                 if (!list_empty(&osc->oo_urgent_exts)) {
1691                         CDEBUG(D_CACHE, "urgent request forcing RPC\n");
1692                         RETURN(1);
1693                 }
1694                 /* trigger a write rpc stream as long as there are dirtiers
1695                  * waiting for space.  as they're waiting, they're not going to
1696                  * create more pages to coalesce with what's waiting.. */
1697                 if (!list_empty(&cli->cl_cache_waiters)) {
1698                         CDEBUG(D_CACHE, "cache waiters forcing RPC\n");
1699                         RETURN(1);
1700                 }
1701                 if (atomic_read(&osc->oo_nr_writes) >=
1702                     cli->cl_max_pages_per_rpc)
1703                         RETURN(1);
1704         } else {
1705                 if (atomic_read(&osc->oo_nr_reads) == 0)
1706                         RETURN(0);
1707                 if (invalid_import) {
1708                         CDEBUG(D_CACHE, "invalid import forcing RPC\n");
1709                         RETURN(1);
1710                 }
1711                 /* all read are urgent. */
1712                 if (!list_empty(&osc->oo_reading_exts))
1713                         RETURN(1);
1714         }
1715
1716         RETURN(0);
1717 }
1718
1719 static void osc_update_pending(struct osc_object *obj, int cmd, int delta)
1720 {
1721         struct client_obd *cli = osc_cli(obj);
1722         if (cmd & OBD_BRW_WRITE) {
1723                 atomic_add(delta, &obj->oo_nr_writes);
1724                 atomic_add(delta, &cli->cl_pending_w_pages);
1725                 LASSERT(atomic_read(&obj->oo_nr_writes) >= 0);
1726         } else {
1727                 atomic_add(delta, &obj->oo_nr_reads);
1728                 atomic_add(delta, &cli->cl_pending_r_pages);
1729                 LASSERT(atomic_read(&obj->oo_nr_reads) >= 0);
1730         }
1731         OSC_IO_DEBUG(obj, "update pending cmd %d delta %d.\n", cmd, delta);
1732 }
1733
1734 static int osc_makes_hprpc(struct osc_object *obj)
1735 {
1736         return !list_empty(&obj->oo_hp_exts);
1737 }
1738
1739 static void on_list(struct list_head *item, struct list_head *list,
1740                     int should_be_on)
1741 {
1742         if (list_empty(item) && should_be_on)
1743                 list_add_tail(item, list);
1744         else if (!list_empty(item) && !should_be_on)
1745                 list_del_init(item);
1746 }
1747
1748 /* maintain the osc's cli list membership invariants so that osc_send_oap_rpc
1749  * can find pages to build into rpcs quickly */
1750 static int __osc_list_maint(struct client_obd *cli, struct osc_object *osc)
1751 {
1752         if (osc_makes_hprpc(osc)) {
1753                 /* HP rpc */
1754                 on_list(&osc->oo_ready_item, &cli->cl_loi_ready_list, 0);
1755                 on_list(&osc->oo_hp_ready_item, &cli->cl_loi_hp_ready_list, 1);
1756         } else {
1757                 on_list(&osc->oo_hp_ready_item, &cli->cl_loi_hp_ready_list, 0);
1758                 on_list(&osc->oo_ready_item, &cli->cl_loi_ready_list,
1759                         osc_makes_rpc(cli, osc, OBD_BRW_WRITE) ||
1760                         osc_makes_rpc(cli, osc, OBD_BRW_READ));
1761         }
1762
1763         on_list(&osc->oo_write_item, &cli->cl_loi_write_list,
1764                 atomic_read(&osc->oo_nr_writes) > 0);
1765
1766         on_list(&osc->oo_read_item, &cli->cl_loi_read_list,
1767                 atomic_read(&osc->oo_nr_reads) > 0);
1768
1769         return osc_is_ready(osc);
1770 }
1771
1772 static int osc_list_maint(struct client_obd *cli, struct osc_object *osc)
1773 {
1774         int is_ready;
1775
1776         spin_lock(&cli->cl_loi_list_lock);
1777         is_ready = __osc_list_maint(cli, osc);
1778         spin_unlock(&cli->cl_loi_list_lock);
1779
1780         return is_ready;
1781 }
1782
1783 /* this is trying to propogate async writeback errors back up to the
1784  * application.  As an async write fails we record the error code for later if
1785  * the app does an fsync.  As long as errors persist we force future rpcs to be
1786  * sync so that the app can get a sync error and break the cycle of queueing
1787  * pages for which writeback will fail. */
1788 static void osc_process_ar(struct osc_async_rc *ar, __u64 xid,
1789                            int rc)
1790 {
1791         if (rc) {
1792                 if (!ar->ar_rc)
1793                         ar->ar_rc = rc;
1794
1795                 ar->ar_force_sync = 1;
1796                 ar->ar_min_xid = ptlrpc_sample_next_xid();
1797                 return;
1798
1799         }
1800
1801         if (ar->ar_force_sync && (xid >= ar->ar_min_xid))
1802                 ar->ar_force_sync = 0;
1803 }
1804
1805 /* this must be called holding the loi list lock to give coverage to exit_cache,
1806  * async_flag maintenance, and oap_request */
1807 static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
1808                               struct osc_async_page *oap, int sent, int rc)
1809 {
1810         struct osc_object *osc = oap->oap_obj;
1811         struct lov_oinfo  *loi = osc->oo_oinfo;
1812         __u64 xid = 0;
1813
1814         ENTRY;
1815         if (oap->oap_request != NULL) {
1816                 xid = ptlrpc_req_xid(oap->oap_request);
1817                 ptlrpc_req_finished(oap->oap_request);
1818                 oap->oap_request = NULL;
1819         }
1820
1821         /* As the transfer for this page is being done, clear the flags */
1822         spin_lock(&oap->oap_lock);
1823         oap->oap_async_flags = 0;
1824         spin_unlock(&oap->oap_lock);
1825         oap->oap_interrupted = 0;
1826
1827         if (oap->oap_cmd & OBD_BRW_WRITE && xid > 0) {
1828                 spin_lock(&cli->cl_loi_list_lock);
1829                 osc_process_ar(&cli->cl_ar, xid, rc);
1830                 osc_process_ar(&loi->loi_ar, xid, rc);
1831                 spin_unlock(&cli->cl_loi_list_lock);
1832         }
1833
1834         rc = osc_completion(env, oap, oap->oap_cmd, rc);
1835         if (rc)
1836                 CERROR("completion on oap %p obj %p returns %d.\n",
1837                        oap, osc, rc);
1838
1839         EXIT;
1840 }
1841
1842 /**
1843  * Try to add extent to one RPC. We need to think about the following things:
1844  * - # of pages must not be over max_pages_per_rpc
1845  * - extent must be compatible with previous ones
1846  */
1847 static int try_to_add_extent_for_io(struct client_obd *cli,
1848                                     struct osc_extent *ext,
1849                                     struct list_head *rpclist,
1850                                     unsigned int *pc, unsigned int *max_pages)
1851 {
1852         struct osc_extent *tmp;
1853         struct osc_async_page *oap = list_first_entry(&ext->oe_pages,
1854                                                       struct osc_async_page,
1855                                                       oap_pending_item);
1856         ENTRY;
1857
1858         EASSERT((ext->oe_state == OES_CACHE || ext->oe_state == OES_LOCK_DONE),
1859                 ext);
1860
1861         *max_pages = max(ext->oe_mppr, *max_pages);
1862         if (*pc + ext->oe_nr_pages > *max_pages)
1863                 RETURN(0);
1864
1865         list_for_each_entry(tmp, rpclist, oe_link) {
1866                 struct osc_async_page *oap2;
1867                 oap2 = list_first_entry(&tmp->oe_pages, struct osc_async_page,
1868                                         oap_pending_item);
1869                 EASSERT(tmp->oe_owner == current, tmp);
1870 #if 0
1871                 if (overlapped(tmp, ext)) {
1872                         OSC_EXTENT_DUMP(D_ERROR, tmp, "overlapped %p.\n", ext);
1873                         EASSERT(0, ext);
1874                 }
1875 #endif
1876                 if (oap2cl_page(oap)->cp_type != oap2cl_page(oap2)->cp_type) {
1877                         CDEBUG(D_CACHE, "Do not permit different type of IO"
1878                                         " for a same RPC\n");
1879                         RETURN(0);
1880                 }
1881
1882                 if (tmp->oe_srvlock != ext->oe_srvlock ||
1883                     !tmp->oe_grants != !ext->oe_grants)
1884                         RETURN(0);
1885
1886                 /* remove break for strict check */
1887                 break;
1888         }
1889
1890         *pc += ext->oe_nr_pages;
1891         list_move_tail(&ext->oe_link, rpclist);
1892         ext->oe_owner = current;
1893         RETURN(1);
1894 }
1895
1896 /**
1897  * In order to prevent multiple ptlrpcd from breaking contiguous extents,
1898  * get_write_extent() takes all appropriate extents in atomic.
1899  *
1900  * The following policy is used to collect extents for IO:
1901  * 1. Add as many HP extents as possible;
1902  * 2. Add the first urgent extent in urgent extent list and take it out of
1903  *    urgent list;
1904  * 3. Add subsequent extents of this urgent extent;
1905  * 4. If urgent list is not empty, goto 2;
1906  * 5. Traverse the extent tree from the 1st extent;
1907  * 6. Above steps exit if there is no space in this RPC.
1908  */
1909 static unsigned int get_write_extents(struct osc_object *obj,
1910                                       struct list_head *rpclist)
1911 {
1912         struct client_obd *cli = osc_cli(obj);
1913         struct osc_extent *ext;
1914         unsigned int page_count = 0;
1915         unsigned int max_pages = cli->cl_max_pages_per_rpc;
1916
1917         LASSERT(osc_object_is_locked(obj));
1918         while (!list_empty(&obj->oo_hp_exts)) {
1919                 ext = list_entry(obj->oo_hp_exts.next, struct osc_extent,
1920                                  oe_link);
1921                 LASSERT(ext->oe_state == OES_CACHE);
1922                 if (!try_to_add_extent_for_io(cli, ext, rpclist, &page_count,
1923                                               &max_pages))
1924                         return page_count;
1925                 EASSERT(ext->oe_nr_pages <= max_pages, ext);
1926         }
1927         if (page_count == max_pages)
1928                 return page_count;
1929
1930         while (!list_empty(&obj->oo_urgent_exts)) {
1931                 ext = list_entry(obj->oo_urgent_exts.next,
1932                                  struct osc_extent, oe_link);
1933                 if (!try_to_add_extent_for_io(cli, ext, rpclist, &page_count,
1934                                               &max_pages))
1935                         return page_count;
1936
1937                 if (!ext->oe_intree)
1938                         continue;
1939
1940                 while ((ext = next_extent(ext)) != NULL) {
1941                         if ((ext->oe_state != OES_CACHE) ||
1942                             (!list_empty(&ext->oe_link) &&
1943                              ext->oe_owner != NULL))
1944                                 continue;
1945
1946                         if (!try_to_add_extent_for_io(cli, ext, rpclist,
1947                                                       &page_count, &max_pages))
1948                                 return page_count;
1949                 }
1950         }
1951         if (page_count == max_pages)
1952                 return page_count;
1953
1954         ext = first_extent(obj);
1955         while (ext != NULL) {
1956                 if ((ext->oe_state != OES_CACHE) ||
1957                     /* this extent may be already in current rpclist */
1958                     (!list_empty(&ext->oe_link) && ext->oe_owner != NULL)) {
1959                         ext = next_extent(ext);
1960                         continue;
1961                 }
1962
1963                 if (!try_to_add_extent_for_io(cli, ext, rpclist, &page_count,
1964                                               &max_pages))
1965                         return page_count;
1966
1967                 ext = next_extent(ext);
1968         }
1969         return page_count;
1970 }
1971
1972 static int
1973 osc_send_write_rpc(const struct lu_env *env, struct client_obd *cli,
1974                    struct osc_object *osc)
1975 __must_hold(osc)
1976 {
1977         struct list_head   rpclist = LIST_HEAD_INIT(rpclist);
1978         struct osc_extent *ext;
1979         struct osc_extent *tmp;
1980         struct osc_extent *first = NULL;
1981         unsigned int page_count = 0;
1982         int srvlock = 0;
1983         int rc = 0;
1984         ENTRY;
1985
1986         LASSERT(osc_object_is_locked(osc));
1987
1988         page_count = get_write_extents(osc, &rpclist);
1989         LASSERT(equi(page_count == 0, list_empty(&rpclist)));
1990
1991         if (list_empty(&rpclist))
1992                 RETURN(0);
1993
1994         osc_update_pending(osc, OBD_BRW_WRITE, -page_count);
1995
1996         list_for_each_entry(ext, &rpclist, oe_link) {
1997                 LASSERT(ext->oe_state == OES_CACHE ||
1998                         ext->oe_state == OES_LOCK_DONE);
1999                 if (ext->oe_state == OES_CACHE)
2000                         osc_extent_state_set(ext, OES_LOCKING);
2001                 else
2002                         osc_extent_state_set(ext, OES_RPC);
2003         }
2004
2005         /* we're going to grab page lock, so release object lock because
2006          * lock order is page lock -> object lock. */
2007         osc_object_unlock(osc);
2008
2009         list_for_each_entry_safe(ext, tmp, &rpclist, oe_link) {
2010                 if (ext->oe_state == OES_LOCKING) {
2011                         rc = osc_extent_make_ready(env, ext);
2012                         if (unlikely(rc < 0)) {
2013                                 list_del_init(&ext->oe_link);
2014                                 osc_extent_finish(env, ext, 0, rc);
2015                                 continue;
2016                         }
2017                 }
2018                 if (first == NULL) {
2019                         first = ext;
2020                         srvlock = ext->oe_srvlock;
2021                 } else {
2022                         LASSERT(srvlock == ext->oe_srvlock);
2023                 }
2024         }
2025
2026         if (!list_empty(&rpclist)) {
2027                 LASSERT(page_count > 0);
2028                 rc = osc_build_rpc(env, cli, &rpclist, OBD_BRW_WRITE);
2029                 LASSERT(list_empty(&rpclist));
2030         }
2031
2032         osc_object_lock(osc);
2033         RETURN(rc);
2034 }
2035
2036 /**
2037  * prepare pages for ASYNC io and put pages in send queue.
2038  *
2039  * \param cmd OBD_BRW_* macroses
2040  * \param lop pending pages
2041  *
2042  * \return zero if no page added to send queue.
2043  * \return 1 if pages successfully added to send queue.
2044  * \return negative on errors.
2045  */
2046 static int
2047 osc_send_read_rpc(const struct lu_env *env, struct client_obd *cli,
2048                   struct osc_object *osc)
2049 __must_hold(osc)
2050 {
2051         struct osc_extent *ext;
2052         struct osc_extent *next;
2053         struct list_head rpclist = LIST_HEAD_INIT(rpclist);
2054         unsigned int page_count = 0;
2055         unsigned int max_pages = cli->cl_max_pages_per_rpc;
2056         int rc = 0;
2057         ENTRY;
2058
2059         LASSERT(osc_object_is_locked(osc));
2060         list_for_each_entry_safe(ext, next,
2061                                      &osc->oo_reading_exts, oe_link) {
2062                 EASSERT(ext->oe_state == OES_LOCK_DONE, ext);
2063                 if (!try_to_add_extent_for_io(cli, ext, &rpclist, &page_count,
2064                                               &max_pages))
2065                         break;
2066                 osc_extent_state_set(ext, OES_RPC);
2067                 EASSERT(ext->oe_nr_pages <= max_pages, ext);
2068         }
2069         LASSERT(page_count <= max_pages);
2070
2071         osc_update_pending(osc, OBD_BRW_READ, -page_count);
2072
2073         if (!list_empty(&rpclist)) {
2074                 osc_object_unlock(osc);
2075
2076                 LASSERT(page_count > 0);
2077                 rc = osc_build_rpc(env, cli, &rpclist, OBD_BRW_READ);
2078                 LASSERT(list_empty(&rpclist));
2079
2080                 osc_object_lock(osc);
2081         }
2082         RETURN(rc);
2083 }
2084
2085 #define list_to_obj(list, item) ({                                            \
2086         struct list_head *__tmp = (list)->next;                               \
2087         list_del_init(__tmp);                                         \
2088         list_entry(__tmp, struct osc_object, oo_##item);                      \
2089 })
2090
2091 /* This is called by osc_check_rpcs() to find which objects have pages that
2092  * we could be sending.  These lists are maintained by osc_makes_rpc(). */
2093 static struct osc_object *osc_next_obj(struct client_obd *cli)
2094 {
2095         ENTRY;
2096
2097         /* First return objects that have blocked locks so that they
2098          * will be flushed quickly and other clients can get the lock,
2099          * then objects which have pages ready to be stuffed into RPCs */
2100         if (!list_empty(&cli->cl_loi_hp_ready_list))
2101                 RETURN(list_to_obj(&cli->cl_loi_hp_ready_list, hp_ready_item));
2102         if (!list_empty(&cli->cl_loi_ready_list))
2103                 RETURN(list_to_obj(&cli->cl_loi_ready_list, ready_item));
2104
2105         /* then if we have cache waiters, return all objects with queued
2106          * writes.  This is especially important when many small files
2107          * have filled up the cache and not been fired into rpcs because
2108          * they don't pass the nr_pending/object threshhold */
2109         if (!list_empty(&cli->cl_cache_waiters) &&
2110             !list_empty(&cli->cl_loi_write_list))
2111                 RETURN(list_to_obj(&cli->cl_loi_write_list, write_item));
2112
2113         /* then return all queued objects when we have an invalid import
2114          * so that they get flushed */
2115         if (cli->cl_import == NULL || cli->cl_import->imp_invalid) {
2116                 if (!list_empty(&cli->cl_loi_write_list))
2117                         RETURN(list_to_obj(&cli->cl_loi_write_list,
2118                                            write_item));
2119                 if (!list_empty(&cli->cl_loi_read_list))
2120                         RETURN(list_to_obj(&cli->cl_loi_read_list,
2121                                            read_item));
2122         }
2123         RETURN(NULL);
2124 }
2125
2126 /* called with the loi list lock held */
2127 static void osc_check_rpcs(const struct lu_env *env, struct client_obd *cli)
2128 __must_hold(&cli->cl_loi_list_lock)
2129 {
2130         struct osc_object *osc;
2131         int rc = 0;
2132         ENTRY;
2133
2134         while ((osc = osc_next_obj(cli)) != NULL) {
2135                 struct cl_object *obj = osc2cl(osc);
2136                 struct lu_ref_link link;
2137
2138                 OSC_IO_DEBUG(osc, "%lu in flight\n", rpcs_in_flight(cli));
2139
2140                 if (osc_max_rpc_in_flight(cli, osc)) {
2141                         __osc_list_maint(cli, osc);
2142                         break;
2143                 }
2144
2145                 cl_object_get(obj);
2146                 spin_unlock(&cli->cl_loi_list_lock);
2147                 lu_object_ref_add_at(&obj->co_lu, &link, "check", current);
2148
2149                 /* attempt some read/write balancing by alternating between
2150                  * reads and writes in an object.  The makes_rpc checks here
2151                  * would be redundant if we were getting read/write work items
2152                  * instead of objects.  we don't want send_oap_rpc to drain a
2153                  * partial read pending queue when we're given this object to
2154                  * do io on writes while there are cache waiters */
2155                 osc_object_lock(osc);
2156                 if (osc_makes_rpc(cli, osc, OBD_BRW_WRITE)) {
2157                         rc = osc_send_write_rpc(env, cli, osc);
2158                         if (rc < 0) {
2159                                 CERROR("Write request failed with %d\n", rc);
2160
2161                                 /* osc_send_write_rpc failed, mostly because of
2162                                  * memory pressure.
2163                                  *
2164                                  * It can't break here, because if:
2165                                  *  - a page was submitted by osc_io_submit, so
2166                                  *    page locked;
2167                                  *  - no request in flight
2168                                  *  - no subsequent request
2169                                  * The system will be in live-lock state,
2170                                  * because there is no chance to call
2171                                  * osc_io_unplug() and osc_check_rpcs() any
2172                                  * more. pdflush can't help in this case,
2173                                  * because it might be blocked at grabbing
2174                                  * the page lock as we mentioned.
2175                                  *
2176                                  * Anyway, continue to drain pages. */
2177                                 /* break; */
2178                         }
2179                 }
2180                 if (osc_makes_rpc(cli, osc, OBD_BRW_READ)) {
2181                         rc = osc_send_read_rpc(env, cli, osc);
2182                         if (rc < 0)
2183                                 CERROR("Read request failed with %d\n", rc);
2184                 }
2185                 osc_object_unlock(osc);
2186
2187                 osc_list_maint(cli, osc);
2188                 lu_object_ref_del_at(&obj->co_lu, &link, "check", current);
2189                 cl_object_put(env, obj);
2190
2191                 spin_lock(&cli->cl_loi_list_lock);
2192         }
2193 }
2194
2195 static int osc_io_unplug0(const struct lu_env *env, struct client_obd *cli,
2196                           struct osc_object *osc, int async)
2197 {
2198         int rc = 0;
2199
2200         if (osc != NULL && osc_list_maint(cli, osc) == 0)
2201                 return 0;
2202
2203         if (!async) {
2204                 spin_lock(&cli->cl_loi_list_lock);
2205                 osc_check_rpcs(env, cli);
2206                 spin_unlock(&cli->cl_loi_list_lock);
2207         } else {
2208                 CDEBUG(D_CACHE, "Queue writeback work for client %p.\n", cli);
2209                 LASSERT(cli->cl_writeback_work != NULL);
2210                 rc = ptlrpcd_queue_work(cli->cl_writeback_work);
2211         }
2212         return rc;
2213 }
2214
2215 static int osc_io_unplug_async(const struct lu_env *env,
2216                                 struct client_obd *cli, struct osc_object *osc)
2217 {
2218         return osc_io_unplug0(env, cli, osc, 1);
2219 }
2220
2221 void osc_io_unplug(const struct lu_env *env, struct client_obd *cli,
2222                    struct osc_object *osc)
2223 {
2224         (void)osc_io_unplug0(env, cli, osc, 0);
2225 }
2226
2227 int osc_prep_async_page(struct osc_object *osc, struct osc_page *ops,
2228                         struct page *page, loff_t offset)
2229 {
2230         struct obd_export     *exp = osc_export(osc);
2231         struct osc_async_page *oap = &ops->ops_oap;
2232         ENTRY;
2233
2234         if (!page)
2235                 return cfs_size_round(sizeof(*oap));
2236
2237         oap->oap_magic = OAP_MAGIC;
2238         oap->oap_cli = &exp->exp_obd->u.cli;
2239         oap->oap_obj = osc;
2240
2241         oap->oap_page = page;
2242         oap->oap_obj_off = offset;
2243         LASSERT(!(offset & ~PAGE_MASK));
2244
2245         if (!client_is_remote(exp) && cfs_capable(CFS_CAP_SYS_RESOURCE))
2246                 oap->oap_brw_flags = OBD_BRW_NOQUOTA;
2247
2248         INIT_LIST_HEAD(&oap->oap_pending_item);
2249         INIT_LIST_HEAD(&oap->oap_rpc_item);
2250
2251         spin_lock_init(&oap->oap_lock);
2252         CDEBUG(D_INFO, "oap %p page %p obj off "LPU64"\n",
2253                oap, page, oap->oap_obj_off);
2254         RETURN(0);
2255 }
2256
2257 int osc_queue_async_io(const struct lu_env *env, struct cl_io *io,
2258                        struct osc_page *ops)
2259 {
2260         struct osc_io *oio = osc_env_io(env);
2261         struct osc_extent     *ext = NULL;
2262         struct osc_async_page *oap = &ops->ops_oap;
2263         struct client_obd     *cli = oap->oap_cli;
2264         struct osc_object     *osc = oap->oap_obj;
2265         pgoff_t index;
2266         unsigned int tmp;
2267         unsigned int grants = 0;
2268         u32    brw_flags = OBD_BRW_ASYNC;
2269         int    cmd = OBD_BRW_WRITE;
2270         int    need_release = 0;
2271         int    rc = 0;
2272         ENTRY;
2273
2274         if (oap->oap_magic != OAP_MAGIC)
2275                 RETURN(-EINVAL);
2276
2277         if (cli->cl_import == NULL || cli->cl_import->imp_invalid)
2278                 RETURN(-EIO);
2279
2280         if (!list_empty(&oap->oap_pending_item) ||
2281             !list_empty(&oap->oap_rpc_item))
2282                 RETURN(-EBUSY);
2283
2284         /* Set the OBD_BRW_SRVLOCK before the page is queued. */
2285         brw_flags |= ops->ops_srvlock ? OBD_BRW_SRVLOCK : 0;
2286         if (!client_is_remote(osc_export(osc)) &&
2287             cfs_capable(CFS_CAP_SYS_RESOURCE)) {
2288                 brw_flags |= OBD_BRW_NOQUOTA;
2289                 cmd |= OBD_BRW_NOQUOTA;
2290         }
2291
2292         /* check if the file's owner/group is over quota */
2293         if (!(cmd & OBD_BRW_NOQUOTA)) {
2294                 struct cl_object *obj;
2295                 struct cl_attr   *attr;
2296                 unsigned int qid[MAXQUOTAS];
2297
2298                 obj = cl_object_top(&osc->oo_cl);
2299                 attr = &osc_env_info(env)->oti_attr;
2300
2301                 cl_object_attr_lock(obj);
2302                 rc = cl_object_attr_get(env, obj, attr);
2303                 cl_object_attr_unlock(obj);
2304
2305                 qid[USRQUOTA] = attr->cat_uid;
2306                 qid[GRPQUOTA] = attr->cat_gid;
2307                 if (rc == 0 && osc_quota_chkdq(cli, qid) == NO_QUOTA)
2308                         rc = -EDQUOT;
2309                 if (rc)
2310                         RETURN(rc);
2311         }
2312
2313         oap->oap_cmd = cmd;
2314         oap->oap_page_off = ops->ops_from;
2315         oap->oap_count = ops->ops_to - ops->ops_from;
2316         /* No need to hold a lock here,
2317          * since this page is not in any list yet. */
2318         oap->oap_async_flags = 0;
2319         oap->oap_brw_flags = brw_flags;
2320
2321         OSC_IO_DEBUG(osc, "oap %p page %p added for cmd %d\n",
2322                      oap, oap->oap_page, oap->oap_cmd & OBD_BRW_RWMASK);
2323
2324         index = osc_index(oap2osc(oap));
2325
2326         /* Add this page into extent by the following steps:
2327          * 1. if there exists an active extent for this IO, mostly this page
2328          *    can be added to the active extent and sometimes we need to
2329          *    expand extent to accomodate this page;
2330          * 2. otherwise, a new extent will be allocated. */
2331
2332         ext = oio->oi_active;
2333         if (ext != NULL && ext->oe_start <= index && ext->oe_max_end >= index) {
2334                 /* one chunk plus extent overhead must be enough to write this
2335                  * page */
2336                 grants = (1 << cli->cl_chunkbits) + cli->cl_extent_tax;
2337                 if (ext->oe_end >= index)
2338                         grants = 0;
2339
2340                 /* it doesn't need any grant to dirty this page */
2341                 spin_lock(&cli->cl_loi_list_lock);
2342                 rc = osc_enter_cache_try(cli, oap, grants, 0);
2343                 spin_unlock(&cli->cl_loi_list_lock);
2344                 if (rc == 0) { /* try failed */
2345                         grants = 0;
2346                         need_release = 1;
2347                 } else if (ext->oe_end < index) {
2348                         tmp = grants;
2349                         /* try to expand this extent */
2350                         rc = osc_extent_expand(ext, index, &tmp);
2351                         if (rc < 0) {
2352                                 need_release = 1;
2353                                 /* don't free reserved grant */
2354                         } else {
2355                                 OSC_EXTENT_DUMP(D_CACHE, ext,
2356                                                 "expanded for %lu.\n", index);
2357                                 osc_unreserve_grant(cli, grants, tmp);
2358                                 grants = 0;
2359                         }
2360                 }
2361                 rc = 0;
2362         } else if (ext != NULL) {
2363                 /* index is located outside of active extent */
2364                 need_release = 1;
2365         }
2366         if (need_release) {
2367                 osc_extent_release(env, ext);
2368                 oio->oi_active = NULL;
2369                 ext = NULL;
2370         }
2371
2372         if (ext == NULL) {
2373                 tmp = (1 << cli->cl_chunkbits) + cli->cl_extent_tax;
2374
2375                 /* try to find new extent to cover this page */
2376                 LASSERT(oio->oi_active == NULL);
2377                 /* we may have allocated grant for this page if we failed
2378                  * to expand the previous active extent. */
2379                 LASSERT(ergo(grants > 0, grants >= tmp));
2380
2381                 rc = 0;
2382                 if (grants == 0) {
2383                         /* we haven't allocated grant for this page. */
2384                         rc = osc_enter_cache(env, cli, oap, tmp);
2385                         if (rc == 0)
2386                                 grants = tmp;
2387                 }
2388
2389                 tmp = grants;
2390                 if (rc == 0) {
2391                         ext = osc_extent_find(env, osc, index, &tmp);
2392                         if (IS_ERR(ext)) {
2393                                 LASSERT(tmp == grants);
2394                                 osc_exit_cache(cli, oap);
2395                                 rc = PTR_ERR(ext);
2396                                 ext = NULL;
2397                         } else {
2398                                 oio->oi_active = ext;
2399                         }
2400                 }
2401                 if (grants > 0)
2402                         osc_unreserve_grant(cli, grants, tmp);
2403         }
2404
2405         LASSERT(ergo(rc == 0, ext != NULL));
2406         if (ext != NULL) {
2407                 EASSERTF(ext->oe_end >= index && ext->oe_start <= index,
2408                          ext, "index = %lu.\n", index);
2409                 LASSERT((oap->oap_brw_flags & OBD_BRW_FROM_GRANT) != 0);
2410
2411                 osc_object_lock(osc);
2412                 if (ext->oe_nr_pages == 0)
2413                         ext->oe_srvlock = ops->ops_srvlock;
2414                 else
2415                         LASSERT(ext->oe_srvlock == ops->ops_srvlock);
2416                 ++ext->oe_nr_pages;
2417                 list_add_tail(&oap->oap_pending_item, &ext->oe_pages);
2418                 osc_object_unlock(osc);
2419         }
2420         RETURN(rc);
2421 }
2422
2423 int osc_teardown_async_page(const struct lu_env *env,
2424                             struct osc_object *obj, struct osc_page *ops)
2425 {
2426         struct osc_async_page *oap = &ops->ops_oap;
2427         int rc = 0;
2428         ENTRY;
2429
2430         LASSERT(oap->oap_magic == OAP_MAGIC);
2431
2432         CDEBUG(D_INFO, "teardown oap %p page %p at index %lu.\n",
2433                oap, ops, osc_index(oap2osc(oap)));
2434
2435         if (!list_empty(&oap->oap_rpc_item)) {
2436                 CDEBUG(D_CACHE, "oap %p is not in cache.\n", oap);
2437                 rc = -EBUSY;
2438         } else if (!list_empty(&oap->oap_pending_item)) {
2439                 struct osc_extent *ext = NULL;
2440
2441                 osc_object_lock(obj);
2442                 ext = osc_extent_lookup(obj, osc_index(oap2osc(oap)));
2443                 osc_object_unlock(obj);
2444                 /* only truncated pages are allowed to be taken out.
2445                  * See osc_extent_truncate() and osc_cache_truncate_start()
2446                  * for details. */
2447                 if (ext != NULL && ext->oe_state != OES_TRUNC) {
2448                         OSC_EXTENT_DUMP(D_ERROR, ext, "trunc at %lu.\n",
2449                                         osc_index(oap2osc(oap)));
2450                         rc = -EBUSY;
2451                 }
2452                 if (ext != NULL)
2453                         osc_extent_put(env, ext);
2454         }
2455         RETURN(rc);
2456 }
2457
2458 /**
2459  * This is called when a page is picked up by kernel to write out.
2460  *
2461  * We should find out the corresponding extent and add the whole extent
2462  * into urgent list. The extent may be being truncated or used, handle it
2463  * carefully.
2464  */
2465 int osc_flush_async_page(const struct lu_env *env, struct cl_io *io,
2466                          struct osc_page *ops)
2467 {
2468         struct osc_extent *ext   = NULL;
2469         struct osc_object *obj   = cl2osc(ops->ops_cl.cpl_obj);
2470         struct cl_page    *cp    = ops->ops_cl.cpl_page;
2471         pgoff_t            index = osc_index(ops);
2472         struct osc_async_page *oap = &ops->ops_oap;
2473         bool unplug = false;
2474         int rc = 0;
2475         ENTRY;
2476
2477         osc_object_lock(obj);
2478         ext = osc_extent_lookup(obj, index);
2479         if (ext == NULL) {
2480                 osc_extent_tree_dump(D_ERROR, obj);
2481                 LASSERTF(0, "page index %lu is NOT covered.\n", index);
2482         }
2483
2484         switch (ext->oe_state) {
2485         case OES_RPC:
2486         case OES_LOCK_DONE:
2487                 CL_PAGE_DEBUG(D_ERROR, env, cp, "flush an in-rpc page?\n");
2488                 LASSERT(0);
2489                 break;
2490         case OES_LOCKING:
2491                 /* If we know this extent is being written out, we should abort
2492                  * so that the writer can make this page ready. Otherwise, there
2493                  * exists a deadlock problem because other process can wait for
2494                  * page writeback bit holding page lock; and meanwhile in
2495                  * vvp_page_make_ready(), we need to grab page lock before
2496                  * really sending the RPC. */
2497         case OES_TRUNC:
2498                 /* race with truncate, page will be redirtied */
2499         case OES_ACTIVE:
2500                 /* The extent is active so we need to abort and let the caller
2501                  * re-dirty the page. If we continued on here, and we were the
2502                  * one making the extent active, we could deadlock waiting for
2503                  * the page writeback to clear but it won't because the extent
2504                  * is active and won't be written out. */
2505                 GOTO(out, rc = -EAGAIN);
2506         default:
2507                 break;
2508         }
2509
2510         rc = cl_page_prep(env, io, cp, CRT_WRITE);
2511         if (rc)
2512                 GOTO(out, rc);
2513
2514         spin_lock(&oap->oap_lock);
2515         oap->oap_async_flags |= ASYNC_READY|ASYNC_URGENT;
2516         spin_unlock(&oap->oap_lock);
2517
2518         if (memory_pressure_get())
2519                 ext->oe_memalloc = 1;
2520
2521         ext->oe_urgent = 1;
2522         if (ext->oe_state == OES_CACHE) {
2523                 OSC_EXTENT_DUMP(D_CACHE, ext,
2524                                 "flush page %p make it urgent.\n", oap);
2525                 if (list_empty(&ext->oe_link))
2526                         list_add_tail(&ext->oe_link, &obj->oo_urgent_exts);
2527                 unplug = true;
2528         }
2529         rc = 0;
2530         EXIT;
2531
2532 out:
2533         osc_object_unlock(obj);
2534         osc_extent_put(env, ext);
2535         if (unplug)
2536                 osc_io_unplug_async(env, osc_cli(obj), obj);
2537         return rc;
2538 }
2539
2540 /**
2541  * this is called when a sync waiter receives an interruption.  Its job is to
2542  * get the caller woken as soon as possible.  If its page hasn't been put in an
2543  * rpc yet it can dequeue immediately.  Otherwise it has to mark the rpc as
2544  * desiring interruption which will forcefully complete the rpc once the rpc
2545  * has timed out.
2546  */
2547 int osc_cancel_async_page(const struct lu_env *env, struct osc_page *ops)
2548 {
2549         struct osc_async_page *oap = &ops->ops_oap;
2550         struct osc_object     *obj = oap->oap_obj;
2551         struct client_obd     *cli = osc_cli(obj);
2552         struct osc_extent     *ext;
2553         struct osc_extent     *found = NULL;
2554         struct list_head            *plist;
2555         pgoff_t index = osc_index(ops);
2556         int     rc = -EBUSY;
2557         int     cmd;
2558         ENTRY;
2559
2560         LASSERT(!oap->oap_interrupted);
2561         oap->oap_interrupted = 1;
2562
2563         /* Find out the caching extent */
2564         osc_object_lock(obj);
2565         if (oap->oap_cmd & OBD_BRW_WRITE) {
2566                 plist = &obj->oo_urgent_exts;
2567                 cmd   = OBD_BRW_WRITE;
2568         } else {
2569                 plist = &obj->oo_reading_exts;
2570                 cmd   = OBD_BRW_READ;
2571         }
2572         list_for_each_entry(ext, plist, oe_link) {
2573                 if (ext->oe_start <= index && ext->oe_end >= index) {
2574                         LASSERT(ext->oe_state == OES_LOCK_DONE);
2575                         /* For OES_LOCK_DONE state extent, it has already held
2576                          * a refcount for RPC. */
2577                         found = osc_extent_get(ext);
2578                         break;
2579                 }
2580         }
2581         if (found != NULL) {
2582                 list_del_init(&found->oe_link);
2583                 osc_update_pending(obj, cmd, -found->oe_nr_pages);
2584                 osc_object_unlock(obj);
2585
2586                 osc_extent_finish(env, found, 0, -EINTR);
2587                 osc_extent_put(env, found);
2588                 rc = 0;
2589         } else {
2590                 osc_object_unlock(obj);
2591                 /* ok, it's been put in an rpc. only one oap gets a request
2592                  * reference */
2593                 if (oap->oap_request != NULL) {
2594                         ptlrpc_mark_interrupted(oap->oap_request);
2595                         ptlrpcd_wake(oap->oap_request);
2596                         ptlrpc_req_finished(oap->oap_request);
2597                         oap->oap_request = NULL;
2598                 }
2599         }
2600
2601         osc_list_maint(cli, obj);
2602         RETURN(rc);
2603 }
2604
2605 int osc_queue_sync_pages(const struct lu_env *env, struct osc_object *obj,
2606                          struct list_head *list, int cmd, int brw_flags)
2607 {
2608         struct client_obd     *cli = osc_cli(obj);
2609         struct osc_extent     *ext;
2610         struct osc_async_page *oap;
2611         int     page_count = 0;
2612         int     mppr       = cli->cl_max_pages_per_rpc;
2613         pgoff_t start      = CL_PAGE_EOF;
2614         pgoff_t end        = 0;
2615         ENTRY;
2616
2617         list_for_each_entry(oap, list, oap_pending_item) {
2618                 pgoff_t index = osc_index(oap2osc(oap));
2619                 if (index > end)
2620                         end = index;
2621                 if (index < start)
2622                         start = index;
2623                 ++page_count;
2624                 mppr <<= (page_count > mppr);
2625         }
2626
2627         ext = osc_extent_alloc(obj);
2628         if (ext == NULL) {
2629                 struct osc_async_page *tmp;
2630
2631                 list_for_each_entry_safe(oap, tmp, list, oap_pending_item) {
2632                         list_del_init(&oap->oap_pending_item);
2633                         osc_ap_completion(env, cli, oap, 0, -ENOMEM);
2634                 }
2635                 RETURN(-ENOMEM);
2636         }
2637
2638         ext->oe_rw = !!(cmd & OBD_BRW_READ);
2639         ext->oe_sync = 1;
2640         ext->oe_urgent = 1;
2641         ext->oe_start = start;
2642         ext->oe_end = ext->oe_max_end = end;
2643         ext->oe_obj = obj;
2644         ext->oe_srvlock = !!(brw_flags & OBD_BRW_SRVLOCK);
2645         ext->oe_nr_pages = page_count;
2646         ext->oe_mppr = mppr;
2647         list_splice_init(list, &ext->oe_pages);
2648
2649         osc_object_lock(obj);
2650         /* Reuse the initial refcount for RPC, don't drop it */
2651         osc_extent_state_set(ext, OES_LOCK_DONE);
2652         if (cmd & OBD_BRW_WRITE) {
2653                 list_add_tail(&ext->oe_link, &obj->oo_urgent_exts);
2654                 osc_update_pending(obj, OBD_BRW_WRITE, page_count);
2655         } else {
2656                 list_add_tail(&ext->oe_link, &obj->oo_reading_exts);
2657                 osc_update_pending(obj, OBD_BRW_READ, page_count);
2658         }
2659         osc_object_unlock(obj);
2660
2661         osc_io_unplug_async(env, cli, obj);
2662         RETURN(0);
2663 }
2664
2665 /**
2666  * Called by osc_io_setattr_start() to freeze and destroy covering extents.
2667  */
2668 int osc_cache_truncate_start(const struct lu_env *env, struct osc_object *obj,
2669                              __u64 size, struct osc_extent **extp)
2670 {
2671         struct client_obd *cli = osc_cli(obj);
2672         struct osc_extent *ext;
2673         struct osc_extent *waiting = NULL;
2674         pgoff_t index;
2675         struct list_head list = LIST_HEAD_INIT(list);
2676         int result = 0;
2677         bool partial;
2678         ENTRY;
2679
2680         /* pages with index greater or equal to index will be truncated. */
2681         index = cl_index(osc2cl(obj), size);
2682         partial = size > cl_offset(osc2cl(obj), index);
2683
2684 again:
2685         osc_object_lock(obj);
2686         ext = osc_extent_search(obj, index);
2687         if (ext == NULL)
2688                 ext = first_extent(obj);
2689         else if (ext->oe_end < index)
2690                 ext = next_extent(ext);
2691         while (ext != NULL) {
2692                 EASSERT(ext->oe_state != OES_TRUNC, ext);
2693
2694                 if (ext->oe_state > OES_CACHE || ext->oe_urgent) {
2695                         /* if ext is in urgent state, it means there must exist
2696                          * a page already having been flushed by write_page().
2697                          * We have to wait for this extent because we can't
2698                          * truncate that page. */
2699                         OSC_EXTENT_DUMP(D_CACHE, ext,
2700                                         "waiting for busy extent\n");
2701                         waiting = osc_extent_get(ext);
2702                         break;
2703                 }
2704
2705                 OSC_EXTENT_DUMP(D_CACHE, ext, "try to trunc:"LPU64".\n", size);
2706
2707                 osc_extent_get(ext);
2708                 if (ext->oe_state == OES_ACTIVE) {
2709                         /* though we grab inode mutex for write path, but we
2710                          * release it before releasing extent(in osc_io_end()),
2711                          * so there is a race window that an extent is still
2712                          * in OES_ACTIVE when truncate starts. */
2713                         LASSERT(!ext->oe_trunc_pending);
2714                         ext->oe_trunc_pending = 1;
2715                 } else {
2716                         EASSERT(ext->oe_state == OES_CACHE, ext);
2717                         osc_extent_state_set(ext, OES_TRUNC);
2718                         osc_update_pending(obj, OBD_BRW_WRITE,
2719                                            -ext->oe_nr_pages);
2720                 }
2721                 EASSERT(list_empty(&ext->oe_link), ext);
2722                 list_add_tail(&ext->oe_link, &list);
2723
2724                 ext = next_extent(ext);
2725         }
2726         osc_object_unlock(obj);
2727
2728         osc_list_maint(cli, obj);
2729
2730         while (!list_empty(&list)) {
2731                 int rc;
2732
2733                 ext = list_entry(list.next, struct osc_extent, oe_link);
2734                 list_del_init(&ext->oe_link);
2735
2736                 /* extent may be in OES_ACTIVE state because inode mutex
2737                  * is released before osc_io_end() in file write case */
2738                 if (ext->oe_state != OES_TRUNC)
2739                         osc_extent_wait(env, ext, OES_TRUNC);
2740
2741                 rc = osc_extent_truncate(ext, index, partial);
2742                 if (rc < 0) {
2743                         if (result == 0)
2744                                 result = rc;
2745
2746                         OSC_EXTENT_DUMP(D_ERROR, ext,
2747                                         "truncate error %d\n", rc);
2748                 } else if (ext->oe_nr_pages == 0) {
2749                         osc_extent_remove(ext);
2750                 } else {
2751                         /* this must be an overlapped extent which means only
2752                          * part of pages in this extent have been truncated.
2753                          */
2754                         EASSERTF(ext->oe_start <= index, ext,
2755                                  "trunc index = %lu/%d.\n", index, partial);
2756                         /* fix index to skip this partially truncated extent */
2757                         index = ext->oe_end + 1;
2758                         partial = false;
2759
2760                         /* we need to hold this extent in OES_TRUNC state so
2761                          * that no writeback will happen. This is to avoid
2762                          * BUG 17397.
2763                          * Only partial truncate can reach here, if @size is
2764                          * not zero, the caller should provide a valid @extp. */
2765                         LASSERT(*extp == NULL);
2766                         *extp = osc_extent_get(ext);
2767                         OSC_EXTENT_DUMP(D_CACHE, ext,
2768                                         "trunc at "LPU64"\n", size);
2769                 }
2770                 osc_extent_put(env, ext);
2771         }
2772         if (waiting != NULL) {
2773                 int rc;
2774
2775                 /* ignore the result of osc_extent_wait the write initiator
2776                  * should take care of it. */
2777                 rc = osc_extent_wait(env, waiting, OES_INV);
2778                 if (rc < 0)
2779                         OSC_EXTENT_DUMP(D_CACHE, waiting, "error: %d.\n", rc);
2780
2781                 osc_extent_put(env, waiting);
2782                 waiting = NULL;
2783                 goto again;
2784         }
2785         RETURN(result);
2786 }
2787
2788 /**
2789  * Called after osc_io_setattr_end to add oio->oi_trunc back to cache.
2790  */
2791 void osc_cache_truncate_end(const struct lu_env *env, struct osc_extent *ext)
2792 {
2793         if (ext != NULL) {
2794                 struct osc_object *obj = ext->oe_obj;
2795                 bool unplug = false;
2796
2797                 EASSERT(ext->oe_nr_pages > 0, ext);
2798                 EASSERT(ext->oe_state == OES_TRUNC, ext);
2799                 EASSERT(!ext->oe_urgent, ext);
2800
2801                 OSC_EXTENT_DUMP(D_CACHE, ext, "trunc -> cache.\n");
2802                 osc_object_lock(obj);
2803                 osc_extent_state_set(ext, OES_CACHE);
2804                 if (ext->oe_fsync_wait && !ext->oe_urgent) {
2805                         ext->oe_urgent = 1;
2806                         list_move_tail(&ext->oe_link, &obj->oo_urgent_exts);
2807                         unplug = true;
2808                 }
2809                 osc_update_pending(obj, OBD_BRW_WRITE, ext->oe_nr_pages);
2810                 osc_object_unlock(obj);
2811                 osc_extent_put(env, ext);
2812
2813                 if (unplug)
2814                         osc_io_unplug_async(env, osc_cli(obj), obj);
2815         }
2816 }
2817
2818 /**
2819  * Wait for extents in a specific range to be written out.
2820  * The caller must have called osc_cache_writeback_range() to issue IO
2821  * otherwise it will take a long time for this function to finish.
2822  *
2823  * Caller must hold inode_mutex , or cancel exclusive dlm lock so that
2824  * nobody else can dirty this range of file while we're waiting for
2825  * extents to be written.
2826  */
2827 int osc_cache_wait_range(const struct lu_env *env, struct osc_object *obj,
2828                          pgoff_t start, pgoff_t end)
2829 {
2830         struct osc_extent *ext;
2831         pgoff_t index = start;
2832         int     result = 0;
2833         ENTRY;
2834
2835 again:
2836         osc_object_lock(obj);
2837         ext = osc_extent_search(obj, index);
2838         if (ext == NULL)
2839                 ext = first_extent(obj);
2840         else if (ext->oe_end < index)
2841                 ext = next_extent(ext);
2842         while (ext != NULL) {
2843                 int rc;
2844
2845                 if (ext->oe_start > end)
2846                         break;
2847
2848                 if (!ext->oe_fsync_wait) {
2849                         ext = next_extent(ext);
2850                         continue;
2851                 }
2852
2853                 EASSERT(ergo(ext->oe_state == OES_CACHE,
2854                              ext->oe_hp || ext->oe_urgent), ext);
2855                 EASSERT(ergo(ext->oe_state == OES_ACTIVE,
2856                              !ext->oe_hp && ext->oe_urgent), ext);
2857
2858                 index = ext->oe_end + 1;
2859                 osc_extent_get(ext);
2860                 osc_object_unlock(obj);
2861
2862                 rc = osc_extent_wait(env, ext, OES_INV);
2863                 if (result == 0)
2864                         result = rc;
2865                 osc_extent_put(env, ext);
2866                 goto again;
2867         }
2868         osc_object_unlock(obj);
2869
2870         OSC_IO_DEBUG(obj, "sync file range.\n");
2871         RETURN(result);
2872 }
2873
2874 /**
2875  * Called to write out a range of osc object.
2876  *
2877  * @hp     : should be set this is caused by lock cancel;
2878  * @discard: is set if dirty pages should be dropped - file will be deleted or
2879  *         truncated, this implies there is no partially discarding extents.
2880  *
2881  * Return how many pages will be issued, or error code if error occurred.
2882  */
2883 int osc_cache_writeback_range(const struct lu_env *env, struct osc_object *obj,
2884                               pgoff_t start, pgoff_t end, int hp, int discard)
2885 {
2886         struct osc_extent *ext;
2887         struct list_head discard_list = LIST_HEAD_INIT(discard_list);
2888         bool unplug = false;
2889         int result = 0;
2890         ENTRY;
2891
2892         osc_object_lock(obj);
2893         ext = osc_extent_search(obj, start);
2894         if (ext == NULL)
2895                 ext = first_extent(obj);
2896         else if (ext->oe_end < start)
2897                 ext = next_extent(ext);
2898         while (ext != NULL) {
2899                 if (ext->oe_start > end)
2900                         break;
2901
2902                 ext->oe_fsync_wait = 1;
2903                 switch (ext->oe_state) {
2904                 case OES_CACHE:
2905                         result += ext->oe_nr_pages;
2906                         if (!discard) {
2907                                 struct list_head *list = NULL;
2908                                 if (hp) {
2909                                         EASSERT(!ext->oe_hp, ext);
2910                                         ext->oe_hp = 1;
2911                                         list = &obj->oo_hp_exts;
2912                                 } else if (!ext->oe_urgent) {
2913                                         ext->oe_urgent = 1;
2914                                         list = &obj->oo_urgent_exts;
2915                                 }
2916                                 if (list != NULL)
2917                                         list_move_tail(&ext->oe_link, list);
2918                                 unplug = true;
2919                         } else {
2920                                 /* the only discarder is lock cancelling, so
2921                                  * [start, end] must contain this extent */
2922                                 EASSERT(ext->oe_start >= start &&
2923                                         ext->oe_max_end <= end, ext);
2924                                 osc_extent_state_set(ext, OES_LOCKING);
2925                                 ext->oe_owner = current;
2926                                 list_move_tail(&ext->oe_link,
2927                                                    &discard_list);
2928                                 osc_update_pending(obj, OBD_BRW_WRITE,
2929                                                    -ext->oe_nr_pages);
2930                         }
2931                         break;
2932                 case OES_ACTIVE:
2933                         /* It's pretty bad to wait for ACTIVE extents, because
2934                          * we don't know how long we will wait for it to be
2935                          * flushed since it may be blocked at awaiting more
2936                          * grants. We do this for the correctness of fsync. */
2937                         LASSERT(hp == 0 && discard == 0);
2938                         ext->oe_urgent = 1;
2939                         break;
2940                 case OES_TRUNC:
2941                         /* this extent is being truncated, can't do anything
2942                          * for it now. it will be set to urgent after truncate
2943                          * is finished in osc_cache_truncate_end(). */
2944                 default:
2945                         break;
2946                 }
2947                 ext = next_extent(ext);
2948         }
2949         osc_object_unlock(obj);
2950
2951         LASSERT(ergo(!discard, list_empty(&discard_list)));
2952         if (!list_empty(&discard_list)) {
2953                 struct osc_extent *tmp;
2954                 int rc;
2955
2956                 osc_list_maint(osc_cli(obj), obj);
2957                 list_for_each_entry_safe(ext, tmp, &discard_list, oe_link) {
2958                         list_del_init(&ext->oe_link);
2959                         EASSERT(ext->oe_state == OES_LOCKING, ext);
2960
2961                         /* Discard caching pages. We don't actually write this
2962                          * extent out but we complete it as if we did. */
2963                         rc = osc_extent_make_ready(env, ext);
2964                         if (unlikely(rc < 0)) {
2965                                 OSC_EXTENT_DUMP(D_ERROR, ext,
2966                                                 "make_ready returned %d\n", rc);
2967                                 if (result >= 0)
2968                                         result = rc;
2969                         }
2970
2971                         /* finish the extent as if the pages were sent */
2972                         osc_extent_finish(env, ext, 0, 0);
2973                 }
2974         }
2975
2976         if (unplug)
2977                 osc_io_unplug(env, osc_cli(obj), obj);
2978
2979         if (hp || discard) {
2980                 int rc;
2981                 rc = osc_cache_wait_range(env, obj, start, end);
2982                 if (result >= 0 && rc < 0)
2983                         result = rc;
2984         }
2985
2986         OSC_IO_DEBUG(obj, "pageout [%lu, %lu], %d.\n", start, end, result);
2987         RETURN(result);
2988 }
2989
2990 /**
2991  * Returns a list of pages by a given [start, end] of \a obj.
2992  *
2993  * \param resched If not NULL, then we give up before hogging CPU for too
2994  * long and set *resched = 1, in that case caller should implement a retry
2995  * logic.
2996  *
2997  * Gang tree lookup (radix_tree_gang_lookup()) optimization is absolutely
2998  * crucial in the face of [offset, EOF] locks.
2999  *
3000  * Return at least one page in @queue unless there is no covered page.
3001  */
3002 int osc_page_gang_lookup(const struct lu_env *env, struct cl_io *io,
3003                         struct osc_object *osc, pgoff_t start, pgoff_t end,
3004                         osc_page_gang_cbt cb, void *cbdata)
3005 {
3006         struct osc_page *ops;
3007         void            **pvec;
3008         pgoff_t         idx;
3009         unsigned int    nr;
3010         unsigned int    i;
3011         unsigned int    j;
3012         int             res = CLP_GANG_OKAY;
3013         bool            tree_lock = true;
3014         ENTRY;
3015
3016         idx = start;
3017         pvec = osc_env_info(env)->oti_pvec;
3018         spin_lock(&osc->oo_tree_lock);
3019         while ((nr = radix_tree_gang_lookup(&osc->oo_tree, pvec,
3020                                             idx, OTI_PVEC_SIZE)) > 0) {
3021                 struct cl_page *page;
3022                 bool end_of_region = false;
3023
3024                 for (i = 0, j = 0; i < nr; ++i) {
3025                         ops = pvec[i];
3026                         pvec[i] = NULL;
3027
3028                         idx = osc_index(ops);
3029                         if (idx > end) {
3030                                 end_of_region = true;
3031                                 break;
3032                         }
3033
3034                         page = ops->ops_cl.cpl_page;
3035                         LASSERT(page->cp_type == CPT_CACHEABLE);
3036                         if (page->cp_state == CPS_FREEING)
3037                                 continue;
3038
3039                         cl_page_get(page);
3040                         lu_ref_add_atomic(&page->cp_reference,
3041                                           "gang_lookup", current);
3042                         pvec[j++] = ops;
3043                 }
3044                 ++idx;
3045
3046                 /*
3047                  * Here a delicate locking dance is performed. Current thread
3048                  * holds a reference to a page, but has to own it before it
3049                  * can be placed into queue. Owning implies waiting, so
3050                  * radix-tree lock is to be released. After a wait one has to
3051                  * check that pages weren't truncated (cl_page_own() returns
3052                  * error in the latter case).
3053                  */
3054                 spin_unlock(&osc->oo_tree_lock);
3055                 tree_lock = false;
3056
3057                 for (i = 0; i < j; ++i) {
3058                         ops = pvec[i];
3059                         if (res == CLP_GANG_OKAY)
3060                                 res = (*cb)(env, io, ops, cbdata);
3061
3062                         page = ops->ops_cl.cpl_page;
3063                         lu_ref_del(&page->cp_reference, "gang_lookup", current);
3064                         cl_page_put(env, page);
3065                 }
3066                 if (nr < OTI_PVEC_SIZE || end_of_region)
3067                         break;
3068
3069                 if (res == CLP_GANG_OKAY && need_resched())
3070                         res = CLP_GANG_RESCHED;
3071                 if (res != CLP_GANG_OKAY)
3072                         break;
3073
3074                 spin_lock(&osc->oo_tree_lock);
3075                 tree_lock = true;
3076         }
3077         if (tree_lock)
3078                 spin_unlock(&osc->oo_tree_lock);
3079         RETURN(res);
3080 }
3081
3082 /**
3083  * Check if page @page is covered by an extra lock or discard it.
3084  */
3085 static int check_and_discard_cb(const struct lu_env *env, struct cl_io *io,
3086                                 struct osc_page *ops, void *cbdata)
3087 {
3088         struct osc_thread_info *info = osc_env_info(env);
3089         struct osc_object *osc = cbdata;
3090         pgoff_t index;
3091
3092         index = osc_index(ops);
3093         if (index >= info->oti_fn_index) {
3094                 struct ldlm_lock *tmp;
3095                 struct cl_page *page = ops->ops_cl.cpl_page;
3096
3097                 /* refresh non-overlapped index */
3098                 tmp = osc_dlmlock_at_pgoff(env, osc, index,
3099                                            OSC_DAP_FL_TEST_LOCK);
3100                 if (tmp != NULL) {
3101                         __u64 end = tmp->l_policy_data.l_extent.end;
3102                         /* Cache the first-non-overlapped index so as to skip
3103                          * all pages within [index, oti_fn_index). This is safe
3104                          * because if tmp lock is canceled, it will discard
3105                          * these pages. */
3106                         info->oti_fn_index = cl_index(osc2cl(osc), end + 1);
3107                         if (end == OBD_OBJECT_EOF)
3108                                 info->oti_fn_index = CL_PAGE_EOF;
3109                         LDLM_LOCK_PUT(tmp);
3110                 } else if (cl_page_own(env, io, page) == 0) {
3111                         /* discard the page */
3112                         cl_page_discard(env, io, page);
3113                         cl_page_disown(env, io, page);
3114                 } else {
3115                         LASSERT(page->cp_state == CPS_FREEING);
3116                 }
3117         }
3118
3119         info->oti_next_index = index + 1;
3120         return CLP_GANG_OKAY;
3121 }
3122
3123 static int discard_cb(const struct lu_env *env, struct cl_io *io,
3124                       struct osc_page *ops, void *cbdata)
3125 {
3126         struct osc_thread_info *info = osc_env_info(env);
3127         struct cl_page *page = ops->ops_cl.cpl_page;
3128
3129         /* page is top page. */
3130         info->oti_next_index = osc_index(ops) + 1;
3131         if (cl_page_own(env, io, page) == 0) {
3132                 if (!ergo(page->cp_type == CPT_CACHEABLE,
3133                           !PageDirty(cl_page_vmpage(page))))
3134                         CL_PAGE_DEBUG(D_ERROR, env, page,
3135                                         "discard dirty page?\n");
3136
3137                 /* discard the page */
3138                 cl_page_discard(env, io, page);
3139                 cl_page_disown(env, io, page);
3140         } else {
3141                 LASSERT(page->cp_state == CPS_FREEING);
3142         }
3143
3144         return CLP_GANG_OKAY;
3145 }
3146
3147 /**
3148  * Discard pages protected by the given lock. This function traverses radix
3149  * tree to find all covering pages and discard them. If a page is being covered
3150  * by other locks, it should remain in cache.
3151  *
3152  * If error happens on any step, the process continues anyway (the reasoning
3153  * behind this being that lock cancellation cannot be delayed indefinitely).
3154  */
3155 int osc_lock_discard_pages(const struct lu_env *env, struct osc_object *osc,
3156                            pgoff_t start, pgoff_t end, enum cl_lock_mode mode)
3157 {
3158         struct osc_thread_info *info = osc_env_info(env);
3159         struct cl_io *io = &info->oti_io;
3160         osc_page_gang_cbt cb;
3161         int res;
3162         int result;
3163
3164         ENTRY;
3165
3166         io->ci_obj = cl_object_top(osc2cl(osc));
3167         io->ci_ignore_layout = 1;
3168         result = cl_io_init(env, io, CIT_MISC, io->ci_obj);
3169         if (result != 0)
3170                 GOTO(out, result);
3171
3172         cb = mode == CLM_READ ? check_and_discard_cb : discard_cb;
3173         info->oti_fn_index = info->oti_next_index = start;
3174         do {
3175                 res = osc_page_gang_lookup(env, io, osc,
3176                                            info->oti_next_index, end, cb, osc);
3177                 if (info->oti_next_index > end)
3178                         break;
3179
3180                 if (res == CLP_GANG_RESCHED)
3181                         cond_resched();
3182         } while (res != CLP_GANG_OKAY);
3183 out:
3184         cl_io_fini(env, io);
3185         RETURN(result);
3186 }
3187
3188
3189 /** @} osc */