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