lustre/osc/osc_cache.c

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see
  18  * http://www.gnu.org/licenses/gpl-2.0.html
  19  *
  20  * GPL HEADER END
  21  */
  22 /*
  23  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  24  * Use is subject to license terms.
  25  *
  26  * Copyright (c) 2012, 2017, Intel Corporation.
  27  *
  28  */
  29 /*
  30  * This file is part of Lustre, http://www.lustre.org/
  31  * Lustre is a trademark of Sun Microsystems, Inc.
  32  *
  33  * osc cache management.
  34  *
  35  * Author: Jinshan Xiong <jinshan.xiong@whamcloud.com>
  36  */
  37
  38 #define DEBUG_SUBSYSTEM S_OSC
  39
  40 #include <lustre_osc.h>
  41 #include <lustre_dlm.h>
  42
  43 #include "osc_internal.h"
  44
  45 static int extent_debug; /* set it to be true for more debug */
  46
  47 static void osc_update_pending(struct osc_object *obj, int cmd, int delta);
  48 static int osc_extent_wait(const struct lu_env *env, struct osc_extent *ext,
  49                            enum osc_extent_state state);
  50 static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
  51                               struct osc_async_page *oap, int sent, int rc);
  52 static int osc_make_ready(const struct lu_env *env, struct osc_async_page *oap,
  53                           int cmd);
  54 static int osc_refresh_count(const struct lu_env *env,
  55                              struct osc_async_page *oap, int cmd);
  56 static int osc_io_unplug_async(const struct lu_env *env,
  57                                struct client_obd *cli, struct osc_object *osc);
  58 static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
  59                            unsigned int lost_grant, unsigned int dirty_grant);
  60
  61 static void osc_extent_tree_dump0(int mask, struct osc_object *obj,
  62                                   const char *func, int line);
  63 #define osc_extent_tree_dump(mask, obj) \
  64         osc_extent_tree_dump0(mask, obj, __func__, __LINE__)
  65
  66 static void osc_unreserve_grant(struct client_obd *cli, unsigned int reserved,
  67                                 unsigned int unused);
  68
  69 /** \addtogroup osc
  70  *  @{
  71  */
  72
  73 /* ------------------ osc extent ------------------ */
  74 static inline char *ext_flags(struct osc_extent *ext, char *flags)
  75 {
  76         char *buf = flags;
  77         *buf++ = ext->oe_rw ? 'r' : 'w';
  78         if (!RB_EMPTY_NODE(&ext->oe_node))
  79                 *buf++ = 'i';
  80         if (ext->oe_sync)
  81                 *buf++ = 'S';
  82         if (ext->oe_srvlock)
  83                 *buf++ = 's';
  84         if (ext->oe_hp)
  85                 *buf++ = 'h';
  86         if (ext->oe_urgent)
  87                 *buf++ = 'u';
  88         if (ext->oe_memalloc)
  89                 *buf++ = 'm';
  90         if (ext->oe_trunc_pending)
  91                 *buf++ = 't';
  92         if (ext->oe_fsync_wait)
  93                 *buf++ = 'Y';
  94         *buf = 0;
  95         return flags;
  96 }
  97
  98 #define EXTSTR       "[%lu -> %lu/%lu]"
  99 #define EXTPARA(ext) (ext)->oe_start, (ext)->oe_end, (ext)->oe_max_end
 100 static const char *oes_strings[] = {
 101         "inv", "active", "cache", "locking", "lockdone", "rpc", "trunc", NULL };
 102
 103 #define OSC_EXTENT_DUMP_WITH_LOC(file, func, line, mask, extent, fmt, ...) do {\
 104         static struct cfs_debug_limit_state cdls;                             \
 105         struct osc_extent *__ext = (extent);                                  \
 106         char __buf[16];                                                       \
 107                                                                               \
 108         __CDEBUG_WITH_LOC(file, func, line, mask, &cdls,                      \
 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                 kref_read(&__ext->oe_refc),                                   \
 115                 atomic_read(&__ext->oe_users),                                \
 116                 list_empty_marker(&__ext->oe_link),                           \
 117                 oes_strings[__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                 waitqueue_active(&__ext->oe_waitq) ? '+' : '-',               \
 123                 __ext->oe_dlmlock, __ext->oe_mppr, __ext->oe_owner,           \
 124                 /* ----- part 4 ----- */                                      \
 125                 ## __VA_ARGS__);                                              \
 126         if (mask == D_ERROR && __ext->oe_dlmlock != NULL)                     \
 127                 LDLM_ERROR(__ext->oe_dlmlock, "extent: %p", __ext);           \
 128         else                                                                  \
 129                 LDLM_DEBUG(__ext->oe_dlmlock, "extent: %p", __ext);           \
 130 } while (0)
 131
 132 #define OSC_EXTENT_DUMP(mask, ext, fmt, ...)                            \
 133         OSC_EXTENT_DUMP_WITH_LOC(__FILE__, __func__, __LINE__,          \
 134                                  mask, ext, fmt, ## __VA_ARGS__)
 135
 136 #undef EASSERTF
 137 #define EASSERTF(expr, ext, fmt, args...) do {                          \
 138         if (!(expr)) {                                                  \
 139                 OSC_EXTENT_DUMP(D_ERROR, (ext), fmt, ##args);           \
 140                 osc_extent_tree_dump(D_ERROR, (ext)->oe_obj);           \
 141                 LASSERT(expr);                                          \
 142         }                                                               \
 143 } while (0)
 144
 145 #undef EASSERT
 146 #define EASSERT(expr, ext) EASSERTF(expr, ext, "\n")
 147
 148 static inline struct osc_extent *rb_extent(struct rb_node *n)
 149 {
 150         return rb_entry_safe(n, struct osc_extent, oe_node);
 151 }
 152
 153 static inline struct osc_extent *next_extent(struct osc_extent *ext)
 154 {
 155         if (ext == NULL)
 156                 return NULL;
 157
 158         LASSERT(!RB_EMPTY_NODE(&ext->oe_node));
 159         return rb_extent(rb_next(&ext->oe_node));
 160 }
 161
 162 static inline struct osc_extent *prev_extent(struct osc_extent *ext)
 163 {
 164         if (ext == NULL)
 165                 return NULL;
 166
 167         LASSERT(!RB_EMPTY_NODE(&ext->oe_node));
 168         return rb_extent(rb_prev(&ext->oe_node));
 169 }
 170
 171 static inline struct osc_extent *first_extent(struct osc_object *obj)
 172 {
 173         return rb_extent(rb_first(&obj->oo_root));
 174 }
 175
 176 /* object must be locked by caller. */
 177 static int osc_extent_sanity_check0(struct osc_extent *ext,
 178                                     const char *func, const int line)
 179 {
 180         struct osc_object *obj = ext->oe_obj;
 181         struct osc_async_page *oap;
 182         size_t page_count;
 183         int rc = 0;
 184
 185         assert_osc_object_is_locked(obj);
 186
 187         if (ext->oe_state >= OES_STATE_MAX)
 188                 GOTO(out, rc = 10);
 189
 190         if (kref_read(&ext->oe_refc) <= 0)
 191                 GOTO(out, rc = 20);
 192
 193         if (kref_read(&ext->oe_refc) < atomic_read(&ext->oe_users))
 194                 GOTO(out, rc = 30);
 195
 196         switch (ext->oe_state) {
 197         case OES_INV:
 198                 if (ext->oe_nr_pages > 0 || !list_empty(&ext->oe_pages))
 199                         GOTO(out, rc = 35);
 200                 GOTO(out, rc = 0);
 201                 break;
 202         case OES_ACTIVE:
 203                 if (atomic_read(&ext->oe_users) == 0)
 204                         GOTO(out, rc = 40);
 205                 if (ext->oe_hp)
 206                         GOTO(out, rc = 50);
 207                 if (ext->oe_fsync_wait && !ext->oe_urgent)
 208                         GOTO(out, rc = 55);
 209                 break;
 210         case OES_CACHE:
 211                 if (ext->oe_grants == 0)
 212                         GOTO(out, rc = 60);
 213                 if (ext->oe_fsync_wait && !ext->oe_urgent && !ext->oe_hp)
 214                         GOTO(out, rc = 65);
 215                 /* fallthrough */
 216         default:
 217                 if (atomic_read(&ext->oe_users) > 0)
 218                         GOTO(out, rc = 70);
 219         }
 220
 221         if (ext->oe_max_end < ext->oe_end || ext->oe_end < ext->oe_start)
 222                 GOTO(out, rc = 80);
 223
 224         if (ext->oe_sync && ext->oe_grants > 0)
 225                 GOTO(out, rc = 90);
 226
 227         if (ext->oe_dlmlock != NULL &&
 228             ext->oe_dlmlock->l_resource->lr_type == LDLM_EXTENT &&
 229             !ldlm_is_failed(ext->oe_dlmlock)) {
 230                 struct ldlm_extent *extent;
 231
 232                 extent = &ext->oe_dlmlock->l_policy_data.l_extent;
 233                 if (!(extent->start <= cl_offset(osc2cl(obj), ext->oe_start) &&
 234                       extent->end   >= cl_offset(osc2cl(obj), ext->oe_max_end)))
 235                         GOTO(out, rc = 100);
 236
 237                 if (!(ext->oe_dlmlock->l_granted_mode & (LCK_PW | LCK_GROUP)))
 238                         GOTO(out, rc = 102);
 239         }
 240
 241         if (ext->oe_nr_pages > ext->oe_mppr)
 242                 GOTO(out, rc = 105);
 243
 244         /* Do not verify page list if extent is in RPC. This is because an
 245          * in-RPC extent is supposed to be exclusively accessible w/o lock. */
 246         if (ext->oe_state > OES_CACHE)
 247                 GOTO(out, rc = 0);
 248
 249         if (!extent_debug)
 250                 GOTO(out, rc = 0);
 251
 252         page_count = 0;
 253         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
 254                 pgoff_t index = osc_index(oap2osc(oap));
 255                 ++page_count;
 256                 if (index > ext->oe_end || index < ext->oe_start)
 257                         GOTO(out, rc = 110);
 258         }
 259         if (page_count != ext->oe_nr_pages)
 260                 GOTO(out, rc = 120);
 261
 262 out:
 263         if (rc != 0)
 264                 OSC_EXTENT_DUMP_WITH_LOC(__FILE__, func, line, D_ERROR, ext,
 265                                          "sanity check %p failed: rc = %d\n",
 266                                          ext, rc);
 267         return rc;
 268 }
 269
 270 #define sanity_check_nolock(ext) \
 271         osc_extent_sanity_check0(ext, __func__, __LINE__)
 272
 273 #define sanity_check(ext) ({                                                   \
 274         int __res;                                                             \
 275         osc_object_lock((ext)->oe_obj);                                        \
 276         __res = sanity_check_nolock(ext);                                      \
 277         osc_object_unlock((ext)->oe_obj);                                      \
 278         __res;                                                                 \
 279 })
 280
 281 static inline bool
 282 overlapped(const struct osc_extent *ex1, const struct osc_extent *ex2)
 283 {
 284         return !(ex1->oe_end < ex2->oe_start || ex2->oe_end < ex1->oe_start);
 285 }
 286
 287 /**
 288  * sanity check - to make sure there is no overlapped extent in the tree.
 289  */
 290 static int osc_extent_is_overlapped(struct osc_object *obj,
 291                                     struct osc_extent *ext)
 292 {
 293         struct osc_extent *tmp;
 294
 295         assert_osc_object_is_locked(obj);
 296
 297         if (!extent_debug)
 298                 return 0;
 299
 300         for (tmp = first_extent(obj); tmp != NULL; tmp = next_extent(tmp)) {
 301                 if (tmp == ext)
 302                         continue;
 303                 if (overlapped(tmp, ext))
 304                         return 1;
 305         }
 306         return 0;
 307 }
 308
 309 static void osc_extent_state_set(struct osc_extent *ext, int state)
 310 {
 311         assert_osc_object_is_locked(ext->oe_obj);
 312         LASSERT(state >= OES_INV && state < OES_STATE_MAX);
 313
 314         /* Never try to sanity check a state changing extent :-) */
 315         /* LASSERT(sanity_check_nolock(ext) == 0); */
 316
 317         /* TODO: validate the state machine */
 318         smp_store_release(&ext->oe_state, state);
 319         wake_up(&ext->oe_waitq);
 320 }
 321
 322 static struct osc_extent *osc_extent_alloc(struct osc_object *obj)
 323 {
 324         struct osc_extent *ext;
 325
 326         OBD_SLAB_ALLOC_PTR_GFP(ext, osc_extent_kmem, GFP_NOFS);
 327         if (ext == NULL)
 328                 return NULL;
 329
 330         RB_CLEAR_NODE(&ext->oe_node);
 331         ext->oe_obj = obj;
 332         cl_object_get(osc2cl(obj));
 333         kref_init(&ext->oe_refc);
 334         atomic_set(&ext->oe_users, 0);
 335         INIT_LIST_HEAD(&ext->oe_link);
 336         ext->oe_state = OES_INV;
 337         INIT_LIST_HEAD(&ext->oe_pages);
 338         init_waitqueue_head(&ext->oe_waitq);
 339         ext->oe_dlmlock = NULL;
 340
 341         return ext;
 342 }
 343
 344 static void osc_extent_free(struct kref *kref)
 345 {
 346         struct osc_extent *ext = container_of(kref, struct osc_extent,
 347                                               oe_refc);
 348
 349         LASSERT(list_empty(&ext->oe_link));
 350         LASSERT(atomic_read(&ext->oe_users) == 0);
 351         LASSERT(ext->oe_state == OES_INV);
 352         LASSERT(RB_EMPTY_NODE(&ext->oe_node));
 353
 354         if (ext->oe_dlmlock) {
 355                 lu_ref_del(&ext->oe_dlmlock->l_reference,
 356                            "osc_extent", ext);
 357                 LDLM_LOCK_PUT(ext->oe_dlmlock);
 358                 ext->oe_dlmlock = NULL;
 359         }
 360 #if 0
 361         /* If/When cl_object_put drops the need for 'env',
 362          * this code can be enabled, and matching code in
 363          * osc_extent_put removed.
 364          */
 365         cl_object_put(osc2cl(ext->oe_obj));
 366
 367         OBD_SLAB_FREE_PTR(ext, osc_extent_kmem);
 368 #endif
 369 }
 370
 371 static struct osc_extent *osc_extent_get(struct osc_extent *ext)
 372 {
 373         LASSERT(kref_read(&ext->oe_refc) >= 0);
 374         kref_get(&ext->oe_refc);
 375         return ext;
 376 }
 377
 378 static void osc_extent_put(const struct lu_env *env, struct osc_extent *ext)
 379 {
 380         LASSERT(kref_read(&ext->oe_refc) > 0);
 381         if (kref_put(&ext->oe_refc, osc_extent_free)) {
 382                 /* This should be in osc_extent_free(), but
 383                  * while we need to pass 'env' it cannot be.
 384                  */
 385                 cl_object_put(env, osc2cl(ext->oe_obj));
 386
 387                 OBD_SLAB_FREE_PTR(ext, osc_extent_kmem);
 388         }
 389 }
 390
 391 /**
 392  * osc_extent_put_trust() is a special version of osc_extent_put() when
 393  * it's known that the caller is not the last user. This is to address the
 394  * problem of lacking of lu_env ;-).
 395  */
 396 static void osc_extent_put_trust(struct osc_extent *ext)
 397 {
 398         LASSERT(kref_read(&ext->oe_refc) > 1);
 399         assert_osc_object_is_locked(ext->oe_obj);
 400         osc_extent_put(NULL, ext);
 401 }
 402
 403 /**
 404  * Return the extent which includes pgoff @index, or return the greatest
 405  * previous extent in the tree.
 406  */
 407 static struct osc_extent *osc_extent_search(struct osc_object *obj,
 408                                             pgoff_t index)
 409 {
 410         struct rb_node    *n = obj->oo_root.rb_node;
 411         struct osc_extent *tmp, *p = NULL;
 412
 413         assert_osc_object_is_locked(obj);
 414         while (n != NULL) {
 415                 tmp = rb_extent(n);
 416                 if (index < tmp->oe_start) {
 417                         n = n->rb_left;
 418                 } else if (index > tmp->oe_end) {
 419                         p = rb_extent(n);
 420                         n = n->rb_right;
 421                 } else {
 422                         return tmp;
 423                 }
 424         }
 425         return p;
 426 }
 427
 428 /*
 429  * Return the extent covering @index, otherwise return NULL.
 430  * caller must have held object lock.
 431  */
 432 static struct osc_extent *osc_extent_lookup(struct osc_object *obj,
 433                                             pgoff_t index)
 434 {
 435         struct osc_extent *ext;
 436
 437         ext = osc_extent_search(obj, index);
 438         if (ext != NULL && ext->oe_start <= index && index <= ext->oe_end)
 439                 return osc_extent_get(ext);
 440         return NULL;
 441 }
 442
 443 /* caller must have held object lock. */
 444 static void osc_extent_insert(struct osc_object *obj, struct osc_extent *ext)
 445 {
 446         struct rb_node   **n      = &obj->oo_root.rb_node;
 447         struct rb_node    *parent = NULL;
 448         struct osc_extent *tmp;
 449
 450         LASSERT(RB_EMPTY_NODE(&ext->oe_node));
 451         LASSERT(ext->oe_obj == obj);
 452         assert_osc_object_is_locked(obj);
 453         while (*n != NULL) {
 454                 tmp = rb_extent(*n);
 455                 parent = *n;
 456
 457                 if (ext->oe_end < tmp->oe_start)
 458                         n = &(*n)->rb_left;
 459                 else if (ext->oe_start > tmp->oe_end)
 460                         n = &(*n)->rb_right;
 461                 else
 462                         EASSERTF(0, tmp, EXTSTR"\n", EXTPARA(ext));
 463         }
 464         rb_link_node(&ext->oe_node, parent, n);
 465         rb_insert_color(&ext->oe_node, &obj->oo_root);
 466         osc_extent_get(ext);
 467 }
 468
 469 /* caller must have held object lock. */
 470 static void osc_extent_erase(struct osc_extent *ext)
 471 {
 472         struct osc_object *obj = ext->oe_obj;
 473         assert_osc_object_is_locked(obj);
 474         if (!RB_EMPTY_NODE(&ext->oe_node)) {
 475                 rb_erase(&ext->oe_node, &obj->oo_root);
 476                 RB_CLEAR_NODE(&ext->oe_node);
 477                 /* rbtree held a refcount */
 478                 osc_extent_put_trust(ext);
 479         }
 480 }
 481
 482 static struct osc_extent *osc_extent_hold(struct osc_extent *ext)
 483 {
 484         struct osc_object *obj = ext->oe_obj;
 485
 486         assert_osc_object_is_locked(obj);
 487         LASSERT(ext->oe_state == OES_ACTIVE || ext->oe_state == OES_CACHE);
 488         if (ext->oe_state == OES_CACHE) {
 489                 osc_extent_state_set(ext, OES_ACTIVE);
 490                 osc_update_pending(obj, OBD_BRW_WRITE, -ext->oe_nr_pages);
 491         }
 492         atomic_inc(&ext->oe_users);
 493         list_del_init(&ext->oe_link);
 494         return osc_extent_get(ext);
 495 }
 496
 497 static void __osc_extent_remove(struct osc_extent *ext)
 498 {
 499         assert_osc_object_is_locked(ext->oe_obj);
 500         LASSERT(list_empty(&ext->oe_pages));
 501         osc_extent_erase(ext);
 502         list_del_init(&ext->oe_link);
 503         osc_extent_state_set(ext, OES_INV);
 504         OSC_EXTENT_DUMP(D_CACHE, ext, "destroyed.\n");
 505 }
 506
 507 static void osc_extent_remove(struct osc_extent *ext)
 508 {
 509         struct osc_object *obj = ext->oe_obj;
 510
 511         osc_object_lock(obj);
 512         __osc_extent_remove(ext);
 513         osc_object_unlock(obj);
 514 }
 515
 516 /**
 517  * This function is used to merge extents to get better performance. It checks
 518  * if @cur and @victim are contiguous at block level.
 519  */
 520 static int osc_extent_merge(const struct lu_env *env, struct osc_extent *cur,
 521                             struct osc_extent *victim)
 522 {
 523         struct osc_object       *obj = cur->oe_obj;
 524         struct client_obd       *cli = osc_cli(obj);
 525         pgoff_t                  chunk_start;
 526         pgoff_t                  chunk_end;
 527         int                      ppc_bits;
 528
 529         LASSERT(cur->oe_state == OES_CACHE);
 530         assert_osc_object_is_locked(obj);
 531         if (victim == NULL)
 532                 return -EINVAL;
 533
 534         if (victim->oe_state != OES_CACHE || victim->oe_fsync_wait)
 535                 return -EBUSY;
 536
 537         if (cur->oe_max_end != victim->oe_max_end)
 538                 return -ERANGE;
 539
 540         /*
 541          * In the rare case max_pages_per_rpc (mppr) is changed, don't
 542          * merge extents until after old ones have been sent, or the
 543          * "extents are aligned to RPCs" checks are unhappy.
 544          */
 545         if (cur->oe_mppr != victim->oe_mppr)
 546                 return -ERANGE;
 547
 548         LASSERT(cur->oe_dlmlock == victim->oe_dlmlock);
 549         ppc_bits = osc_cli(obj)->cl_chunkbits - PAGE_SHIFT;
 550         chunk_start = cur->oe_start >> ppc_bits;
 551         chunk_end   = cur->oe_end   >> ppc_bits;
 552         if (chunk_start   != (victim->oe_end >> ppc_bits) + 1 &&
 553             chunk_end + 1 != victim->oe_start >> ppc_bits)
 554                 return -ERANGE;
 555
 556         /* overall extent size should not exceed the max supported limit
 557          * reported by the server */
 558         if (cur->oe_end - cur->oe_start + 1 +
 559             victim->oe_end - victim->oe_start + 1 > cli->cl_max_extent_pages)
 560                 return -ERANGE;
 561
 562         OSC_EXTENT_DUMP(D_CACHE, victim, "will be merged by %p.\n", cur);
 563
 564         cur->oe_start     = min(cur->oe_start, victim->oe_start);
 565         cur->oe_end       = max(cur->oe_end,   victim->oe_end);
 566         /* per-extent tax should be accounted only once for the whole extent */
 567         cur->oe_grants   += victim->oe_grants - cli->cl_grant_extent_tax;
 568         cur->oe_nr_pages += victim->oe_nr_pages;
 569         /* only the following bits are needed to merge */
 570         cur->oe_urgent   |= victim->oe_urgent;
 571         cur->oe_memalloc |= victim->oe_memalloc;
 572         list_splice_init(&victim->oe_pages, &cur->oe_pages);
 573         victim->oe_nr_pages = 0;
 574
 575         osc_extent_get(victim);
 576         __osc_extent_remove(victim);
 577         osc_extent_put(env, victim);
 578
 579         OSC_EXTENT_DUMP(D_CACHE, cur, "after merging %p.\n", victim);
 580         return 0;
 581 }
 582
 583 /**
 584  * Drop user count of osc_extent, and unplug IO asynchronously.
 585  */
 586 int osc_extent_release(const struct lu_env *env, struct osc_extent *ext)
 587 {
 588         struct osc_object *obj = ext->oe_obj;
 589         struct client_obd *cli = osc_cli(obj);
 590         int rc = 0;
 591         ENTRY;
 592
 593         LASSERT(atomic_read(&ext->oe_users) > 0);
 594         LASSERT(sanity_check(ext) == 0);
 595         LASSERT(ext->oe_grants > 0);
 596
 597         if (atomic_dec_and_lock(&ext->oe_users, &obj->oo_lock)) {
 598                 LASSERT(ext->oe_state == OES_ACTIVE);
 599                 if (ext->oe_trunc_pending) {
 600                         /* a truncate process is waiting for this extent.
 601                          * This may happen due to a race, check
 602                          * osc_cache_truncate_start(). */
 603                         osc_extent_state_set(ext, OES_TRUNC);
 604                         ext->oe_trunc_pending = 0;
 605                         osc_object_unlock(obj);
 606                 } else {
 607                         int grant = 0;
 608
 609                         osc_extent_state_set(ext, OES_CACHE);
 610                         osc_update_pending(obj, OBD_BRW_WRITE,
 611                                            ext->oe_nr_pages);
 612
 613                         /* try to merge the previous and next extent. */
 614                         if (osc_extent_merge(env, ext, prev_extent(ext)) == 0)
 615                                 grant += cli->cl_grant_extent_tax;
 616                         if (osc_extent_merge(env, ext, next_extent(ext)) == 0)
 617                                 grant += cli->cl_grant_extent_tax;
 618
 619                         if (ext->oe_hp)
 620                                 list_move_tail(&ext->oe_link,
 621                                                &obj->oo_hp_exts);
 622                         else if (ext->oe_urgent)
 623                                 list_move_tail(&ext->oe_link,
 624                                                &obj->oo_urgent_exts);
 625                         else if (ext->oe_nr_pages == ext->oe_mppr) {
 626                                 list_move_tail(&ext->oe_link,
 627                                                &obj->oo_full_exts);
 628                         }
 629                         osc_object_unlock(obj);
 630                         if (grant > 0)
 631                                 osc_unreserve_grant(cli, 0, grant);
 632                 }
 633
 634                 osc_io_unplug_async(env, cli, obj);
 635         }
 636         osc_extent_put(env, ext);
 637         RETURN(rc);
 638 }
 639
 640 /**
 641  * Find or create an extent which includes @index, core function to manage
 642  * extent tree.
 643  */
 644 static struct osc_extent *osc_extent_find(const struct lu_env *env,
 645                                           struct osc_object *obj, pgoff_t index,
 646                                           unsigned int *grants)
 647 {
 648         struct client_obd *cli = osc_cli(obj);
 649         struct osc_lock   *olck;
 650         struct cl_lock_descr *descr;
 651         struct osc_extent *cur;
 652         struct osc_extent *ext;
 653         struct osc_extent *conflict = NULL;
 654         struct osc_extent *found = NULL;
 655         pgoff_t    chunk;
 656         pgoff_t    max_end;
 657         unsigned int max_pages; /* max_pages_per_rpc */
 658         unsigned int chunksize;
 659         int        ppc_bits; /* pages per chunk bits */
 660         pgoff_t    chunk_mask;
 661         int        rc;
 662         ENTRY;
 663
 664         cur = osc_extent_alloc(obj);
 665         if (cur == NULL)
 666                 RETURN(ERR_PTR(-ENOMEM));
 667
 668         olck = osc_env_io(env)->oi_write_osclock;
 669         LASSERTF(olck != NULL, "page %lu is not covered by lock\n", index);
 670         LASSERT(olck->ols_state == OLS_GRANTED);
 671
 672         descr = &olck->ols_cl.cls_lock->cll_descr;
 673         LASSERT(descr->cld_mode >= CLM_WRITE);
 674
 675         LASSERTF(cli->cl_chunkbits >= PAGE_SHIFT,
 676                  "chunkbits: %u\n", cli->cl_chunkbits);
 677         ppc_bits   = cli->cl_chunkbits - PAGE_SHIFT;
 678         chunk_mask = ~((1 << ppc_bits) - 1);
 679         chunksize  = 1 << cli->cl_chunkbits;
 680         chunk      = index >> ppc_bits;
 681
 682         /* align end to RPC edge. */
 683         max_pages = cli->cl_max_pages_per_rpc;
 684         if ((max_pages & ~chunk_mask) != 0) {
 685                 CERROR("max_pages: %#x chunkbits: %u chunk_mask: %#lx\n",
 686                        max_pages, cli->cl_chunkbits, chunk_mask);
 687                 RETURN(ERR_PTR(-EINVAL));
 688         }
 689         max_end = index - (index % max_pages) + max_pages - 1;
 690         max_end = min_t(pgoff_t, max_end, descr->cld_end);
 691
 692         /* initialize new extent by parameters so far */
 693         cur->oe_max_end = max_end;
 694         cur->oe_start   = index & chunk_mask;
 695         cur->oe_end     = ((index + ~chunk_mask + 1) & chunk_mask) - 1;
 696         if (cur->oe_start < descr->cld_start)
 697                 cur->oe_start = descr->cld_start;
 698         if (cur->oe_end > max_end)
 699                 cur->oe_end = max_end;
 700         cur->oe_grants  = chunksize + cli->cl_grant_extent_tax;
 701         cur->oe_mppr    = max_pages;
 702         if (olck->ols_dlmlock != NULL) {
 703                 LASSERT(olck->ols_hold);
 704                 cur->oe_dlmlock = LDLM_LOCK_GET(olck->ols_dlmlock);
 705                 lu_ref_add(&olck->ols_dlmlock->l_reference, "osc_extent", cur);
 706         }
 707
 708         /* grants has been allocated by caller */
 709         LASSERTF(*grants >= chunksize + cli->cl_grant_extent_tax,
 710                  "%u/%u/%u.\n", *grants, chunksize, cli->cl_grant_extent_tax);
 711         LASSERTF((max_end - cur->oe_start) < max_pages, EXTSTR"\n",
 712                  EXTPARA(cur));
 713
 714 restart:
 715         osc_object_lock(obj);
 716         ext = osc_extent_search(obj, cur->oe_start);
 717         if (!ext)
 718                 ext = first_extent(obj);
 719         for (; ext; ext = next_extent(ext)) {
 720                 pgoff_t ext_chk_start = ext->oe_start >> ppc_bits;
 721                 pgoff_t ext_chk_end = ext->oe_end >> ppc_bits;
 722
 723                 LASSERT(sanity_check_nolock(ext) == 0);
 724                 if (chunk > ext_chk_end + 1 || chunk < ext_chk_start)
 725                         break;
 726
 727                 /* if covering by different locks, no chance to match */
 728                 if (olck->ols_dlmlock != ext->oe_dlmlock) {
 729                         EASSERTF(!overlapped(ext, cur), ext,
 730                                  EXTSTR"\n", EXTPARA(cur));
 731
 732                         continue;
 733                 }
 734
 735                 /* discontiguous chunks? */
 736                 if (chunk + 1 < ext_chk_start)
 737                         continue;
 738
 739                 /* ok, from now on, ext and cur have these attrs:
 740                  * 1. covered by the same lock
 741                  * 2. contiguous at chunk level or overlapping. */
 742
 743                 if (overlapped(ext, cur)) {
 744                         /* cur is the minimum unit, so overlapping means
 745                          * full contain. */
 746                         EASSERTF((ext->oe_start <= cur->oe_start &&
 747                                   ext->oe_end >= cur->oe_end),
 748                                  ext, EXTSTR"\n", EXTPARA(cur));
 749
 750                         if (ext->oe_state > OES_CACHE || ext->oe_fsync_wait) {
 751                                 /* for simplicity, we wait for this extent to
 752                                  * finish before going forward. */
 753                                 conflict = osc_extent_get(ext);
 754                                 break;
 755                         }
 756
 757                         found = osc_extent_hold(ext);
 758                         break;
 759                 }
 760
 761                 /* non-overlapped extent */
 762                 if (ext->oe_state != OES_CACHE || ext->oe_fsync_wait)
 763                         /* we can't do anything for a non OES_CACHE extent, or
 764                          * if there is someone waiting for this extent to be
 765                          * flushed, try next one. */
 766                         continue;
 767
 768                 if (osc_extent_merge(env, ext, cur) == 0) {
 769                         LASSERT(*grants >= chunksize);
 770                         *grants -= chunksize;
 771                         found = osc_extent_hold(ext);
 772
 773                         /*
 774                          * Try to merge with the next one too because we
 775                          * might have just filled in a gap.
 776                          */
 777                         if (osc_extent_merge(env, ext, next_extent(ext)) == 0)
 778                                 /* we can save extent tax from next extent */
 779                                 *grants += cli->cl_grant_extent_tax;
 780
 781                         break;
 782                 }
 783         }
 784
 785         osc_extent_tree_dump(D_CACHE, obj);
 786         if (found != NULL) {
 787                 LASSERT(conflict == NULL);
 788                 if (!IS_ERR(found)) {
 789                         LASSERT(found->oe_dlmlock == cur->oe_dlmlock);
 790                         OSC_EXTENT_DUMP(D_CACHE, found,
 791                                         "found caching ext for %lu.\n", index);
 792                 }
 793         } else if (conflict == NULL) {
 794                 /* create a new extent */
 795                 EASSERT(osc_extent_is_overlapped(obj, cur) == 0, cur);
 796                 LASSERT(*grants >= cur->oe_grants);
 797                 *grants -= cur->oe_grants;
 798
 799                 cur->oe_state = OES_CACHE;
 800                 found = osc_extent_hold(cur);
 801                 osc_extent_insert(obj, cur);
 802                 OSC_EXTENT_DUMP(D_CACHE, cur, "add into tree %lu/%lu.\n",
 803                                 index, descr->cld_end);
 804         }
 805         osc_object_unlock(obj);
 806
 807         if (conflict != NULL) {
 808                 LASSERT(found == NULL);
 809
 810                 /* waiting for IO to finish. Please notice that it's impossible
 811                  * to be an OES_TRUNC extent. */
 812                 rc = osc_extent_wait(env, conflict, OES_INV);
 813                 osc_extent_put(env, conflict);
 814                 conflict = NULL;
 815                 if (rc < 0)
 816                         GOTO(out, found = ERR_PTR(rc));
 817
 818                 goto restart;
 819         }
 820         EXIT;
 821
 822 out:
 823         osc_extent_put(env, cur);
 824         return found;
 825 }
 826
 827 /**
 828  * Called when IO is finished to an extent.
 829  */
 830 int osc_extent_finish(const struct lu_env *env, struct osc_extent *ext,
 831                       int sent, int rc)
 832 {
 833         struct client_obd *cli = osc_cli(ext->oe_obj);
 834         struct osc_async_page *oap;
 835         struct osc_async_page *tmp;
 836         int nr_pages = ext->oe_nr_pages;
 837         int lost_grant = 0;
 838         int blocksize = cli->cl_import->imp_obd->obd_osfs.os_bsize ? : 4096;
 839         loff_t last_off = 0;
 840         int last_count = -1;
 841         ENTRY;
 842
 843         OSC_EXTENT_DUMP(D_CACHE, ext, "extent finished.\n");
 844
 845         ext->oe_rc = rc ?: ext->oe_nr_pages;
 846         EASSERT(ergo(rc == 0, ext->oe_state == OES_RPC), ext);
 847
 848         osc_lru_add_batch(cli, &ext->oe_pages);
 849         list_for_each_entry_safe(oap, tmp, &ext->oe_pages,
 850                                      oap_pending_item) {
 851                 list_del_init(&oap->oap_rpc_item);
 852                 list_del_init(&oap->oap_pending_item);
 853                 if (last_off <= oap->oap_obj_off) {
 854                         last_off = oap->oap_obj_off;
 855                         last_count = oap->oap_count;
 856                 }
 857
 858                 --ext->oe_nr_pages;
 859                 osc_ap_completion(env, cli, oap, sent, rc);
 860         }
 861         EASSERT(ext->oe_nr_pages == 0, ext);
 862
 863         if (!sent) {
 864                 lost_grant = ext->oe_grants;
 865         } else if (blocksize < PAGE_SIZE &&
 866                    last_count != PAGE_SIZE) {
 867                 /* For short writes we shouldn't count parts of pages that
 868                  * span a whole chunk on the OST side, or our accounting goes
 869                  * wrong.  Should match the code in filter_grant_check. */
 870                 int offset = last_off & ~PAGE_MASK;
 871                 int count = last_count + (offset & (blocksize - 1));
 872                 int end = (offset + last_count) & (blocksize - 1);
 873                 if (end)
 874                         count += blocksize - end;
 875
 876                 lost_grant = PAGE_SIZE - count;
 877         }
 878         if (ext->oe_grants > 0)
 879                 osc_free_grant(cli, nr_pages, lost_grant, ext->oe_grants);
 880
 881         osc_extent_remove(ext);
 882         /* put the refcount for RPC */
 883         osc_extent_put(env, ext);
 884         RETURN(0);
 885 }
 886
 887 /**
 888  * Wait for the extent's state to become @state.
 889  */
 890 static int osc_extent_wait(const struct lu_env *env, struct osc_extent *ext,
 891                            enum osc_extent_state state)
 892 {
 893         struct osc_object *obj = ext->oe_obj;
 894         int rc = 0;
 895         ENTRY;
 896
 897         osc_object_lock(obj);
 898         LASSERT(sanity_check_nolock(ext) == 0);
 899         /* `Kick' this extent only if the caller is waiting for it to be
 900          * written out. */
 901         if (state == OES_INV && !ext->oe_urgent && !ext->oe_hp) {
 902                 if (ext->oe_state == OES_ACTIVE) {
 903                         ext->oe_urgent = 1;
 904                 } else if (ext->oe_state == OES_CACHE) {
 905                         ext->oe_urgent = 1;
 906                         osc_extent_hold(ext);
 907                         rc = 1;
 908                 }
 909         }
 910         osc_object_unlock(obj);
 911         if (rc == 1)
 912                 osc_extent_release(env, ext);
 913
 914         /* wait for the extent until its state becomes @state */
 915         rc = wait_event_idle_timeout(ext->oe_waitq,
 916                                      smp_load_acquire(&ext->oe_state) == state,
 917                                      cfs_time_seconds(600));
 918         if (rc == 0) {
 919                 OSC_EXTENT_DUMP(D_ERROR, ext,
 920                         "%s: wait ext to %u timedout, recovery in progress?\n",
 921                         cli_name(osc_cli(obj)), state);
 922
 923                 wait_event_idle(ext->oe_waitq,
 924                                 smp_load_acquire(&ext->oe_state) == state);
 925         }
 926         if (ext->oe_rc < 0)
 927                 rc = ext->oe_rc;
 928         else
 929                 rc = 0;
 930         RETURN(rc);
 931 }
 932
 933 /**
 934  * Discard pages with index greater than @size. If @ext is overlapped with
 935  * @size, then partial truncate happens.
 936  */
 937 static int osc_extent_truncate(struct osc_extent *ext, pgoff_t trunc_index,
 938                                 bool partial)
 939 {
 940         struct lu_env         *env;
 941         struct cl_io          *io;
 942         struct osc_object     *obj = ext->oe_obj;
 943         struct client_obd     *cli = osc_cli(obj);
 944         struct osc_async_page *oap;
 945         struct osc_async_page *tmp;
 946         struct pagevec        *pvec;
 947         int                    pages_in_chunk = 0;
 948         int                    ppc_bits    = cli->cl_chunkbits -
 949                                              PAGE_SHIFT;
 950         __u64                  trunc_chunk = trunc_index >> ppc_bits;
 951         int                    grants   = 0;
 952         int                    nr_pages = 0;
 953         int                    rc       = 0;
 954         __u16                  refcheck;
 955         ENTRY;
 956
 957         LASSERT(sanity_check(ext) == 0);
 958         LASSERT(ext->oe_state == OES_TRUNC);
 959         LASSERT(!ext->oe_urgent);
 960
 961         /* Request new lu_env.
 962          * We can't use that env from osc_cache_truncate_start() because
 963          * it's from lov_io_sub and not fully initialized. */
 964         env = cl_env_get(&refcheck);
 965         if (IS_ERR(env))
 966                 RETURN(PTR_ERR(env));
 967
 968         io  = osc_env_thread_io(env);
 969         io->ci_obj = cl_object_top(osc2cl(obj));
 970         io->ci_ignore_layout = 1;
 971         pvec = &osc_env_info(env)->oti_pagevec;
 972         ll_pagevec_init(pvec, 0);
 973         rc = cl_io_init(env, io, CIT_MISC, io->ci_obj);
 974         if (rc < 0)
 975                 GOTO(out, rc);
 976
 977         /* discard all pages with index greater than trunc_index */
 978         list_for_each_entry_safe(oap, tmp, &ext->oe_pages,
 979                                      oap_pending_item) {
 980                 pgoff_t index = osc_index(oap2osc(oap));
 981                 struct cl_page  *page = oap2cl_page(oap);
 982
 983                 LASSERT(list_empty(&oap->oap_rpc_item));
 984
 985                 /* only discard the pages with their index greater than
 986                  * trunc_index, and ... */
 987                 if (index < trunc_index ||
 988                     (index == trunc_index && partial)) {
 989                         /* accounting how many pages remaining in the chunk
 990                          * so that we can calculate grants correctly. */
 991                         if (index >> ppc_bits == trunc_chunk)
 992                                 ++pages_in_chunk;
 993                         continue;
 994                 }
 995
 996                 list_del_init(&oap->oap_pending_item);
 997
 998                 cl_page_get(page);
 999                 lu_ref_add(&page->cp_reference, "truncate", current);
1000
1001                 if (cl_page_own(env, io, page) == 0) {
1002                         cl_page_discard(env, io, page);
1003                         cl_page_disown(env, io, page);
1004                 } else {
1005                         LASSERT(page->cp_state == CPS_FREEING);
1006                         LASSERT(0);
1007                 }
1008
1009                 lu_ref_del(&page->cp_reference, "truncate", current);
1010                 cl_pagevec_put(env, page, pvec);
1011
1012                 --ext->oe_nr_pages;
1013                 ++nr_pages;
1014         }
1015         pagevec_release(pvec);
1016
1017         EASSERTF(ergo(ext->oe_start >= trunc_index + !!partial,
1018                       ext->oe_nr_pages == 0),
1019                 ext, "trunc_index %lu, partial %d\n", trunc_index, partial);
1020
1021         osc_object_lock(obj);
1022         if (ext->oe_nr_pages == 0) {
1023                 LASSERT(pages_in_chunk == 0);
1024                 grants = ext->oe_grants;
1025                 ext->oe_grants = 0;
1026         } else { /* calculate how many grants we can free */
1027                 int     chunks = (ext->oe_end >> ppc_bits) - trunc_chunk;
1028                 pgoff_t last_index;
1029
1030
1031                 /* if there is no pages in this chunk, we can also free grants
1032                  * for the last chunk */
1033                 if (pages_in_chunk == 0) {
1034                         /* if this is the 1st chunk and no pages in this chunk,
1035                          * ext->oe_nr_pages must be zero, so we should be in
1036                          * the other if-clause. */
1037                         LASSERT(trunc_chunk > 0);
1038                         --trunc_chunk;
1039                         ++chunks;
1040                 }
1041
1042                 /* this is what we can free from this extent */
1043                 grants          = chunks << cli->cl_chunkbits;
1044                 ext->oe_grants -= grants;
1045                 last_index      = ((trunc_chunk + 1) << ppc_bits) - 1;
1046                 ext->oe_end     = min(last_index, ext->oe_max_end);
1047                 LASSERT(ext->oe_end >= ext->oe_start);
1048                 LASSERT(ext->oe_grants > 0);
1049         }
1050         osc_object_unlock(obj);
1051
1052         if (grants > 0 || nr_pages > 0)
1053                 osc_free_grant(cli, nr_pages, grants, grants);
1054
1055 out:
1056         cl_io_fini(env, io);
1057         cl_env_put(env, &refcheck);
1058         RETURN(rc);
1059 }
1060
1061 /**
1062  * This function is used to make the extent prepared for transfer.
1063  * A race with flusing page - ll_writepage() has to be handled cautiously.
1064  */
1065 static int osc_extent_make_ready(const struct lu_env *env,
1066                                  struct osc_extent *ext)
1067 {
1068         struct osc_async_page *oap;
1069         struct osc_async_page *last = NULL;
1070         struct osc_object *obj = ext->oe_obj;
1071         unsigned int page_count = 0;
1072         int rc;
1073         ENTRY;
1074
1075         /* we're going to grab page lock, so object lock must not be taken. */
1076         LASSERT(sanity_check(ext) == 0);
1077         /* in locking state, any process should not touch this extent. */
1078         EASSERT(ext->oe_state == OES_LOCKING, ext);
1079         EASSERT(ext->oe_owner != NULL, ext);
1080
1081         OSC_EXTENT_DUMP(D_CACHE, ext, "make ready\n");
1082
1083         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
1084                 ++page_count;
1085                 if (last == NULL || last->oap_obj_off < oap->oap_obj_off)
1086                         last = oap;
1087
1088                 /* checking ASYNC_READY is race safe */
1089                 if ((oap->oap_async_flags & ASYNC_READY) != 0)
1090                         continue;
1091
1092                 rc = osc_make_ready(env, oap, OBD_BRW_WRITE);
1093                 switch (rc) {
1094                 case 0:
1095                         spin_lock(&oap->oap_lock);
1096                         oap->oap_async_flags |= ASYNC_READY;
1097                         spin_unlock(&oap->oap_lock);
1098                         break;
1099                 case -EALREADY:
1100                         LASSERT((oap->oap_async_flags & ASYNC_READY) != 0);
1101                         break;
1102                 default:
1103                         LASSERTF(0, "unknown return code: %d\n", rc);
1104                 }
1105         }
1106
1107         LASSERT(page_count == ext->oe_nr_pages);
1108         LASSERT(last != NULL);
1109         /* the last page is the only one we need to refresh its count by
1110          * the size of file. */
1111         if (!(last->oap_async_flags & ASYNC_COUNT_STABLE)) {
1112                 int last_oap_count = osc_refresh_count(env, last, OBD_BRW_WRITE);
1113                 LASSERT(last_oap_count > 0);
1114                 LASSERT(last->oap_page_off + last_oap_count <= PAGE_SIZE);
1115                 last->oap_count = last_oap_count;
1116                 spin_lock(&last->oap_lock);
1117                 last->oap_async_flags |= ASYNC_COUNT_STABLE;
1118                 spin_unlock(&last->oap_lock);
1119         }
1120
1121         /* for the rest of pages, we don't need to call osf_refresh_count()
1122          * because it's known they are not the last page */
1123         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
1124                 if (!(oap->oap_async_flags & ASYNC_COUNT_STABLE)) {
1125                         oap->oap_count = PAGE_SIZE - oap->oap_page_off;
1126                         spin_lock(&oap->oap_lock);
1127                         oap->oap_async_flags |= ASYNC_COUNT_STABLE;
1128                         spin_unlock(&oap->oap_lock);
1129                 }
1130         }
1131
1132         osc_object_lock(obj);
1133         osc_extent_state_set(ext, OES_RPC);
1134         osc_object_unlock(obj);
1135         /* get a refcount for RPC. */
1136         osc_extent_get(ext);
1137
1138         RETURN(0);
1139 }
1140
1141 /**
1142  * Quick and simple version of osc_extent_find(). This function is frequently
1143  * called to expand the extent for the same IO. To expand the extent, the
1144  * page index must be in the same or next chunk of ext->oe_end.
1145  */
1146 static int osc_extent_expand(struct osc_extent *ext, pgoff_t index,
1147                              unsigned int *grants)
1148 {
1149         struct osc_object *obj = ext->oe_obj;
1150         struct client_obd *cli = osc_cli(obj);
1151         struct osc_extent *next;
1152         int ppc_bits = cli->cl_chunkbits - PAGE_SHIFT;
1153         pgoff_t chunk = index >> ppc_bits;
1154         pgoff_t end_chunk;
1155         pgoff_t end_index;
1156         unsigned int chunksize = 1 << cli->cl_chunkbits;
1157         int rc = 0;
1158         ENTRY;
1159
1160         LASSERT(ext->oe_max_end >= index && ext->oe_start <= index);
1161         osc_object_lock(obj);
1162         LASSERT(sanity_check_nolock(ext) == 0);
1163         end_chunk = ext->oe_end >> ppc_bits;
1164         if (chunk > end_chunk + 1)
1165                 GOTO(out, rc = -ERANGE);
1166
1167         if (end_chunk >= chunk)
1168                 GOTO(out, rc = 0);
1169
1170         LASSERT(end_chunk + 1 == chunk);
1171
1172         /* try to expand this extent to cover @index */
1173         end_index = min(ext->oe_max_end, ((chunk + 1) << ppc_bits) - 1);
1174
1175         /* don't go over the maximum extent size reported by server */
1176         if (end_index - ext->oe_start + 1 > cli->cl_max_extent_pages)
1177                 GOTO(out, rc = -ERANGE);
1178
1179         next = next_extent(ext);
1180         if (next != NULL && next->oe_start <= end_index)
1181                 /* complex mode - overlapped with the next extent,
1182                  * this case will be handled by osc_extent_find() */
1183                 GOTO(out, rc = -EAGAIN);
1184
1185         ext->oe_end = end_index;
1186         ext->oe_grants += chunksize;
1187         LASSERT(*grants >= chunksize);
1188         *grants -= chunksize;
1189         EASSERTF(osc_extent_is_overlapped(obj, ext) == 0, ext,
1190                  "overlapped after expanding for %lu.\n", index);
1191         EXIT;
1192
1193 out:
1194         osc_object_unlock(obj);
1195         RETURN(rc);
1196 }
1197
1198 static void osc_extent_tree_dump0(int mask, struct osc_object *obj,
1199                                   const char *func, int line)
1200 {
1201         struct osc_extent *ext;
1202         int cnt;
1203
1204         if (!cfs_cdebug_show(mask, DEBUG_SUBSYSTEM))
1205                 return;
1206
1207         CDEBUG(mask, "Dump object %p extents at %s:%d, mppr: %u.\n",
1208                obj, func, line, osc_cli(obj)->cl_max_pages_per_rpc);
1209
1210         /* osc_object_lock(obj); */
1211         cnt = 1;
1212         for (ext = first_extent(obj); ext != NULL; ext = next_extent(ext))
1213                 OSC_EXTENT_DUMP(mask, ext, "in tree %d.\n", cnt++);
1214
1215         cnt = 1;
1216         list_for_each_entry(ext, &obj->oo_hp_exts, oe_link)
1217                 OSC_EXTENT_DUMP(mask, ext, "hp %d.\n", cnt++);
1218
1219         cnt = 1;
1220         list_for_each_entry(ext, &obj->oo_urgent_exts, oe_link)
1221                 OSC_EXTENT_DUMP(mask, ext, "urgent %d.\n", cnt++);
1222
1223         cnt = 1;
1224         list_for_each_entry(ext, &obj->oo_reading_exts, oe_link)
1225                 OSC_EXTENT_DUMP(mask, ext, "reading %d.\n", cnt++);
1226         /* osc_object_unlock(obj); */
1227 }
1228
1229 /* ------------------ osc extent end ------------------ */
1230
1231 static inline int osc_is_ready(struct osc_object *osc)
1232 {
1233         return !list_empty(&osc->oo_ready_item) ||
1234                !list_empty(&osc->oo_hp_ready_item);
1235 }
1236
1237 #define OSC_IO_DEBUG(OSC, STR, args...)                                        \
1238         CDEBUG(D_CACHE, "obj %p ready %d|%c|%c wr %d|%c|%c rd %d|%c " STR,     \
1239                (OSC), osc_is_ready(OSC),                                       \
1240                list_empty_marker(&(OSC)->oo_hp_ready_item),                    \
1241                list_empty_marker(&(OSC)->oo_ready_item),                       \
1242                atomic_read(&(OSC)->oo_nr_writes),                              \
1243                list_empty_marker(&(OSC)->oo_hp_exts),                          \
1244                list_empty_marker(&(OSC)->oo_urgent_exts),                      \
1245                atomic_read(&(OSC)->oo_nr_reads),                               \
1246                list_empty_marker(&(OSC)->oo_reading_exts),                     \
1247                ##args)
1248
1249 static int osc_make_ready(const struct lu_env *env, struct osc_async_page *oap,
1250                           int cmd)
1251 {
1252         struct osc_page *opg  = oap2osc_page(oap);
1253         struct cl_page  *page = oap2cl_page(oap);
1254         int result;
1255
1256         LASSERT(cmd == OBD_BRW_WRITE); /* no cached reads */
1257
1258         ENTRY;
1259         result = cl_page_make_ready(env, page, CRT_WRITE);
1260         if (result == 0)
1261                 opg->ops_submit_time = ktime_get();
1262         RETURN(result);
1263 }
1264
1265 static int osc_refresh_count(const struct lu_env *env,
1266                              struct osc_async_page *oap, int cmd)
1267 {
1268         struct osc_page  *opg = oap2osc_page(oap);
1269         pgoff_t index = osc_index(oap2osc(oap));
1270         struct cl_object *obj;
1271         struct cl_attr   *attr = &osc_env_info(env)->oti_attr;
1272         int result;
1273         loff_t kms;
1274
1275         /* readpage queues with _COUNT_STABLE, shouldn't get here. */
1276         LASSERT(!(cmd & OBD_BRW_READ));
1277         LASSERT(opg != NULL);
1278         obj = opg->ops_cl.cpl_obj;
1279
1280         cl_object_attr_lock(obj);
1281         result = cl_object_attr_get(env, obj, attr);
1282         cl_object_attr_unlock(obj);
1283         if (result < 0)
1284                 return result;
1285         kms = attr->cat_kms;
1286         if (cl_offset(obj, index) >= kms)
1287                 /* catch race with truncate */
1288                 return 0;
1289         else if (cl_offset(obj, index + 1) > kms)
1290                 /* catch sub-page write at end of file */
1291                 return kms & ~PAGE_MASK;
1292         else
1293                 return PAGE_SIZE;
1294 }
1295
1296 static int osc_completion(const struct lu_env *env, struct osc_async_page *oap,
1297                           int cmd, int rc)
1298 {
1299         struct osc_page   *opg  = oap2osc_page(oap);
1300         struct cl_page    *page = oap2cl_page(oap);
1301         enum cl_req_type   crt;
1302         int srvlock;
1303
1304         ENTRY;
1305
1306         cmd &= ~OBD_BRW_NOQUOTA;
1307         LASSERTF(equi(page->cp_state == CPS_PAGEIN,  cmd == OBD_BRW_READ),
1308                  "cp_state:%u, cmd:%d\n", page->cp_state, cmd);
1309         LASSERTF(equi(page->cp_state == CPS_PAGEOUT, cmd == OBD_BRW_WRITE),
1310                 "cp_state:%u, cmd:%d\n", page->cp_state, cmd);
1311         LASSERT(opg->ops_transfer_pinned);
1312
1313         crt = cmd == OBD_BRW_READ ? CRT_READ : CRT_WRITE;
1314         /* Clear opg->ops_transfer_pinned before VM lock is released. */
1315         opg->ops_transfer_pinned = 0;
1316
1317         opg->ops_submit_time = ktime_set(0, 0);
1318         srvlock = oap->oap_brw_flags & OBD_BRW_SRVLOCK;
1319
1320         /* statistic */
1321         if (rc == 0 && srvlock) {
1322                 struct lu_device *ld    = opg->ops_cl.cpl_obj->co_lu.lo_dev;
1323                 struct osc_stats *stats = &lu2osc_dev(ld)->od_stats;
1324                 size_t bytes = oap->oap_count;
1325
1326                 if (crt == CRT_READ)
1327                         stats->os_lockless_reads += bytes;
1328                 else
1329                         stats->os_lockless_writes += bytes;
1330         }
1331
1332         /*
1333          * This has to be the last operation with the page, as locks are
1334          * released in cl_page_completion() and nothing except for the
1335          * reference counter protects page from concurrent reclaim.
1336          */
1337         lu_ref_del(&page->cp_reference, "transfer", page);
1338
1339         cl_page_completion(env, page, crt, rc);
1340         cl_page_put(env, page);
1341
1342         RETURN(0);
1343 }
1344
1345 #define OSC_DUMP_GRANT(mask, cli, fmt, args...) do {                    \
1346         struct client_obd *__tmp = (cli);                               \
1347         CDEBUG(mask, "%s: grant { dirty: %ld/%ld dirty_pages: %ld/%lu " \
1348                "dropped: %ld avail: %ld, dirty_grant: %ld, "            \
1349                "reserved: %ld, flight: %d } lru {in list: %ld, "        \
1350                "left: %ld, waiters: %d }" fmt "\n",                     \
1351                cli_name(__tmp),                                         \
1352                __tmp->cl_dirty_pages, __tmp->cl_dirty_max_pages,        \
1353                atomic_long_read(&obd_dirty_pages), obd_max_dirty_pages, \
1354                __tmp->cl_lost_grant, __tmp->cl_avail_grant,             \
1355                __tmp->cl_dirty_grant,                                   \
1356                __tmp->cl_reserved_grant, __tmp->cl_w_in_flight,         \
1357                atomic_long_read(&__tmp->cl_lru_in_list),                \
1358                atomic_long_read(&__tmp->cl_lru_busy),                   \
1359                atomic_read(&__tmp->cl_lru_shrinkers), ##args);          \
1360 } while (0)
1361
1362 /* caller must hold loi_list_lock */
1363 static void osc_consume_write_grant(struct client_obd *cli,
1364                                     struct brw_page *pga)
1365 {
1366         assert_spin_locked(&cli->cl_loi_list_lock);
1367         LASSERT(!(pga->flag & OBD_BRW_FROM_GRANT));
1368         cli->cl_dirty_pages++;
1369         pga->flag |= OBD_BRW_FROM_GRANT;
1370         CDEBUG(D_CACHE, "using %lu grant credits for brw %p page %p\n",
1371                PAGE_SIZE, pga, pga->pg);
1372         osc_update_next_shrink(cli);
1373 }
1374
1375 /* the companion to osc_consume_write_grant, called when a brw has completed.
1376  * must be called with the loi lock held. */
1377 static void osc_release_write_grant(struct client_obd *cli,
1378                                     struct brw_page *pga)
1379 {
1380         ENTRY;
1381
1382         assert_spin_locked(&cli->cl_loi_list_lock);
1383         if (!(pga->flag & OBD_BRW_FROM_GRANT)) {
1384                 EXIT;
1385                 return;
1386         }
1387
1388         pga->flag &= ~OBD_BRW_FROM_GRANT;
1389         atomic_long_dec(&obd_dirty_pages);
1390         cli->cl_dirty_pages--;
1391         EXIT;
1392 }
1393
1394 /**
1395  * To avoid sleeping with object lock held, it's good for us allocate enough
1396  * grants before entering into critical section.
1397  *
1398  * client_obd_list_lock held by caller
1399  */
1400 static int osc_reserve_grant(struct client_obd *cli, unsigned int bytes)
1401 {
1402         int rc = -EDQUOT;
1403
1404         if (cli->cl_avail_grant >= bytes) {
1405                 cli->cl_avail_grant    -= bytes;
1406                 cli->cl_reserved_grant += bytes;
1407                 rc = 0;
1408         }
1409         return rc;
1410 }
1411
1412 static void __osc_unreserve_grant(struct client_obd *cli,
1413                                   unsigned int reserved, unsigned int unused)
1414 {
1415         /* it's quite normal for us to get more grant than reserved.
1416          * Thinking about a case that two extents merged by adding a new
1417          * chunk, we can save one extent tax. If extent tax is greater than
1418          * one chunk, we can save more grant by adding a new chunk */
1419         cli->cl_reserved_grant -= reserved;
1420         if (unused > reserved) {
1421                 cli->cl_avail_grant += reserved;
1422                 cli->cl_lost_grant  += unused - reserved;
1423                 cli->cl_dirty_grant -= unused - reserved;
1424         } else {
1425                 cli->cl_avail_grant += unused;
1426                 cli->cl_dirty_grant += reserved - unused;
1427         }
1428 }
1429
1430 static void osc_unreserve_grant_nolock(struct client_obd *cli,
1431                                        unsigned int reserved,
1432                                        unsigned int unused)
1433 {
1434         __osc_unreserve_grant(cli, reserved, unused);
1435         if (unused > 0)
1436                 osc_wake_cache_waiters(cli);
1437 }
1438
1439 static void osc_unreserve_grant(struct client_obd *cli,
1440                                 unsigned int reserved, unsigned int unused)
1441 {
1442         spin_lock(&cli->cl_loi_list_lock);
1443         osc_unreserve_grant_nolock(cli, reserved, unused);
1444         spin_unlock(&cli->cl_loi_list_lock);
1445 }
1446
1447 /**
1448  * Free grant after IO is finished or canceled.
1449  *
1450  * @lost_grant is used to remember how many grants we have allocated but not
1451  * used, we should return these grants to OST. There're two cases where grants
1452  * can be lost:
1453  * 1. truncate;
1454  * 2. blocksize at OST is less than PAGE_SIZE and a partial page was
1455  *    written. In this case OST may use less chunks to serve this partial
1456  *    write. OSTs don't actually know the page size on the client side. so
1457  *    clients have to calculate lost grant by the blocksize on the OST.
1458  *    See filter_grant_check() for details.
1459  */
1460 static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
1461                            unsigned int lost_grant, unsigned int dirty_grant)
1462 {
1463         unsigned long grant;
1464
1465         grant = (1 << cli->cl_chunkbits) + cli->cl_grant_extent_tax;
1466
1467         spin_lock(&cli->cl_loi_list_lock);
1468         atomic_long_sub(nr_pages, &obd_dirty_pages);
1469         cli->cl_dirty_pages -= nr_pages;
1470         cli->cl_lost_grant += lost_grant;
1471         cli->cl_dirty_grant -= dirty_grant;
1472         if (cli->cl_avail_grant < grant && cli->cl_lost_grant >= grant) {
1473                 /* borrow some grant from truncate to avoid the case that
1474                  * truncate uses up all avail grant */
1475                 cli->cl_lost_grant -= grant;
1476                 cli->cl_avail_grant += grant;
1477         }
1478         osc_wake_cache_waiters(cli);
1479         spin_unlock(&cli->cl_loi_list_lock);
1480         CDEBUG(D_CACHE, "lost %u grant: %lu avail: %lu dirty: %lu/%lu\n",
1481                lost_grant, cli->cl_lost_grant,
1482                cli->cl_avail_grant, cli->cl_dirty_pages << PAGE_SHIFT,
1483                cli->cl_dirty_grant);
1484 }
1485
1486 /**
1487  * The companion to osc_enter_cache(), called when @oap is no longer part of
1488  * the dirty accounting due to error.
1489  */
1490 static void osc_exit_cache(struct client_obd *cli, struct osc_async_page *oap)
1491 {
1492         spin_lock(&cli->cl_loi_list_lock);
1493         osc_release_write_grant(cli, &oap->oap_brw_page);
1494         spin_unlock(&cli->cl_loi_list_lock);
1495 }
1496
1497 /**
1498  * Non-blocking version of osc_enter_cache() that consumes grant only when it
1499  * is available.
1500  */
1501 static int osc_enter_cache_try(struct client_obd *cli,
1502                                struct osc_async_page *oap,
1503                                int bytes)
1504 {
1505         int rc;
1506
1507         OSC_DUMP_GRANT(D_CACHE, cli, "need:%d\n", bytes);
1508
1509         rc = osc_reserve_grant(cli, bytes);
1510         if (rc < 0)
1511                 return 0;
1512
1513         if (cli->cl_dirty_pages < cli->cl_dirty_max_pages) {
1514                 if (atomic_long_add_return(1, &obd_dirty_pages) <=
1515                     obd_max_dirty_pages) {
1516                         osc_consume_write_grant(cli, &oap->oap_brw_page);
1517                         rc = 1;
1518                         goto out;
1519                 } else
1520                         atomic_long_dec(&obd_dirty_pages);
1521         }
1522         __osc_unreserve_grant(cli, bytes, bytes);
1523
1524 out:
1525         return rc;
1526 }
1527
1528 /* Following two inlines exist to pass code fragments
1529  * to wait_event_idle_exclusive_timeout_cmd().  Passing
1530  * code fragments as macro args can look confusing, so
1531  * we provide inlines to encapsulate them.
1532  */
1533 static inline void cli_unlock_and_unplug(const struct lu_env *env,
1534                                          struct client_obd *cli,
1535                                          struct osc_async_page *oap)
1536 {
1537         spin_unlock(&cli->cl_loi_list_lock);
1538         osc_io_unplug_async(env, cli, NULL);
1539         CDEBUG(D_CACHE,
1540                "%s: sleeping for cache space for %p\n",
1541                cli_name(cli), oap);
1542 }
1543
1544 static inline void cli_lock_after_unplug(struct client_obd *cli)
1545 {
1546         spin_lock(&cli->cl_loi_list_lock);
1547 }
1548 /**
1549  * The main entry to reserve dirty page accounting. Usually the grant reserved
1550  * in this function will be freed in bulk in osc_free_grant() unless it fails
1551  * to add osc cache, in that case, it will be freed in osc_exit_cache().
1552  *
1553  * The process will be put into sleep if it's already run out of grant.
1554  */
1555 static int osc_enter_cache(const struct lu_env *env, struct client_obd *cli,
1556                            struct osc_async_page *oap, int bytes)
1557 {
1558         struct osc_object *osc = oap->oap_obj;
1559         struct lov_oinfo *loi = osc->oo_oinfo;
1560         int rc = -EDQUOT;
1561         int remain;
1562         bool entered = false;
1563         /* We cannot wait for a long time here since we are holding ldlm lock
1564          * across the actual IO. If no requests complete fast (e.g. due to
1565          * overloaded OST that takes a long time to process everything, we'd
1566          * get evicted if we wait for a normal obd_timeout or some such.
1567          * So we try to wait half the time it would take the client to be
1568          * evicted by server which is half obd_timeout when AT is off
1569          * or at least ldlm_enqueue_min with AT on.
1570          * See LU-13131 */
1571         unsigned long timeout = cfs_time_seconds(AT_OFF ? obd_timeout / 2 :
1572                                                           ldlm_enqueue_min / 2);
1573
1574         ENTRY;
1575
1576         OSC_DUMP_GRANT(D_CACHE, cli, "need:%d\n", bytes);
1577
1578         spin_lock(&cli->cl_loi_list_lock);
1579
1580         /* force the caller to try sync io.  this can jump the list
1581          * of queued writes and create a discontiguous rpc stream */
1582         if (OBD_FAIL_CHECK(OBD_FAIL_OSC_NO_GRANT) ||
1583             cli->cl_dirty_max_pages == 0 ||
1584             cli->cl_ar.ar_force_sync || loi->loi_ar.ar_force_sync) {
1585                 OSC_DUMP_GRANT(D_CACHE, cli, "forced sync i/o\n");
1586                 GOTO(out, rc = -EDQUOT);
1587         }
1588
1589         /*
1590          * We can wait here for two reasons: too many dirty pages in cache, or
1591          * run out of grants. In both cases we should write dirty pages out.
1592          * Adding a cache waiter will trigger urgent write-out no matter what
1593          * RPC size will be.
1594          * The exiting condition (other than success) is no avail grants
1595          * and no dirty pages caching, that really means there is no space
1596          * on the OST.
1597          */
1598         remain = wait_event_idle_exclusive_timeout_cmd(
1599                 cli->cl_cache_waiters,
1600                 (entered = osc_enter_cache_try(cli, oap, bytes)) ||
1601                 (cli->cl_dirty_pages == 0 && cli->cl_w_in_flight == 0),
1602                 timeout,
1603                 cli_unlock_and_unplug(env, cli, oap),
1604                 cli_lock_after_unplug(cli));
1605
1606         if (entered) {
1607                 if (remain == timeout)
1608                         OSC_DUMP_GRANT(D_CACHE, cli, "granted from cache\n");
1609                 else
1610                         OSC_DUMP_GRANT(D_CACHE, cli,
1611                                        "finally got grant space\n");
1612                 wake_up(&cli->cl_cache_waiters);
1613                 rc = 0;
1614         } else if (remain == 0) {
1615                 OSC_DUMP_GRANT(D_CACHE, cli,
1616                                "timeout, fall back to sync i/o\n");
1617                 osc_extent_tree_dump(D_CACHE, osc);
1618                 /* fall back to synchronous I/O */
1619         } else {
1620                 OSC_DUMP_GRANT(D_CACHE, cli,
1621                                "no grant space, fall back to sync i/o\n");
1622                 wake_up_all(&cli->cl_cache_waiters);
1623         }
1624         EXIT;
1625 out:
1626         spin_unlock(&cli->cl_loi_list_lock);
1627         RETURN(rc);
1628 }
1629
1630 static int osc_max_rpc_in_flight(struct client_obd *cli, struct osc_object *osc)
1631 {
1632         int hprpc = !!list_empty(&osc->oo_hp_exts);
1633         return rpcs_in_flight(cli) >= cli->cl_max_rpcs_in_flight + hprpc;
1634 }
1635
1636 /* This maintains the lists of pending pages to read/write for a given object
1637  * (lop).  This is used by osc_check_rpcs->osc_next_obj() and osc_list_maint()
1638  * to quickly find objects that are ready to send an RPC. */
1639 static int osc_makes_rpc(struct client_obd *cli, struct osc_object *osc,
1640                          int cmd)
1641 {
1642         int invalid_import = 0;
1643         ENTRY;
1644
1645         /* if we have an invalid import we want to drain the queued pages
1646          * by forcing them through rpcs that immediately fail and complete
1647          * the pages.  recovery relies on this to empty the queued pages
1648          * before canceling the locks and evicting down the llite pages */
1649         if ((cli->cl_import == NULL || cli->cl_import->imp_invalid))
1650                 invalid_import = 1;
1651
1652         if (cmd & OBD_BRW_WRITE) {
1653                 if (atomic_read(&osc->oo_nr_writes) == 0)
1654                         RETURN(0);
1655                 if (invalid_import) {
1656                         CDEBUG(D_CACHE, "invalid import forcing RPC\n");
1657                         RETURN(1);
1658                 }
1659                 if (!list_empty(&osc->oo_hp_exts)) {
1660                         CDEBUG(D_CACHE, "high prio request forcing RPC\n");
1661                         RETURN(1);
1662                 }
1663                 if (!list_empty(&osc->oo_urgent_exts)) {
1664                         CDEBUG(D_CACHE, "urgent request forcing RPC\n");
1665                         RETURN(1);
1666                 }
1667                 /* trigger a write rpc stream as long as there are dirtiers
1668                  * waiting for space.  as they're waiting, they're not going to
1669                  * create more pages to coalesce with what's waiting..
1670                  */
1671                 if (waitqueue_active(&cli->cl_cache_waiters)) {
1672                         CDEBUG(D_CACHE, "cache waiters forcing RPC\n");
1673                         RETURN(1);
1674                 }
1675                 if (!list_empty(&osc->oo_full_exts)) {
1676                         CDEBUG(D_CACHE, "full extent ready, make an RPC\n");
1677                         RETURN(1);
1678                 }
1679         } else {
1680                 if (atomic_read(&osc->oo_nr_reads) == 0)
1681                         RETURN(0);
1682                 if (invalid_import) {
1683                         CDEBUG(D_CACHE, "invalid import forcing RPC\n");
1684                         RETURN(1);
1685                 }
1686                 /* all read are urgent. */
1687                 if (!list_empty(&osc->oo_reading_exts))
1688                         RETURN(1);
1689         }
1690
1691         RETURN(0);
1692 }
1693
1694 static void osc_update_pending(struct osc_object *obj, int cmd, int delta)
1695 {
1696         struct client_obd *cli = osc_cli(obj);
1697         if (cmd & OBD_BRW_WRITE) {
1698                 atomic_add(delta, &obj->oo_nr_writes);
1699                 atomic_add(delta, &cli->cl_pending_w_pages);
1700                 LASSERT(atomic_read(&obj->oo_nr_writes) >= 0);
1701         } else {
1702                 atomic_add(delta, &obj->oo_nr_reads);
1703                 atomic_add(delta, &cli->cl_pending_r_pages);
1704                 LASSERT(atomic_read(&obj->oo_nr_reads) >= 0);
1705         }
1706         OSC_IO_DEBUG(obj, "update pending cmd %d delta %d.\n", cmd, delta);
1707 }
1708
1709 static int osc_makes_hprpc(struct osc_object *obj)
1710 {
1711         return !list_empty(&obj->oo_hp_exts);
1712 }
1713
1714 static void on_list(struct list_head *item, struct list_head *list,
1715                     int should_be_on)
1716 {
1717         if (list_empty(item) && should_be_on)
1718                 list_add_tail(item, list);
1719         else if (!list_empty(item) && !should_be_on)
1720                 list_del_init(item);
1721 }
1722
1723 /* maintain the osc's cli list membership invariants so that osc_send_oap_rpc
1724  * can find pages to build into rpcs quickly */
1725 static int __osc_list_maint(struct client_obd *cli, struct osc_object *osc)
1726 {
1727         if (osc_makes_hprpc(osc)) {
1728                 /* HP rpc */
1729                 on_list(&osc->oo_ready_item, &cli->cl_loi_ready_list, 0);
1730                 on_list(&osc->oo_hp_ready_item, &cli->cl_loi_hp_ready_list, 1);
1731         } else {
1732                 on_list(&osc->oo_hp_ready_item, &cli->cl_loi_hp_ready_list, 0);
1733                 on_list(&osc->oo_ready_item, &cli->cl_loi_ready_list,
1734                         osc_makes_rpc(cli, osc, OBD_BRW_WRITE) ||
1735                         osc_makes_rpc(cli, osc, OBD_BRW_READ));
1736         }
1737
1738         on_list(&osc->oo_write_item, &cli->cl_loi_write_list,
1739                 atomic_read(&osc->oo_nr_writes) > 0);
1740
1741         on_list(&osc->oo_read_item, &cli->cl_loi_read_list,
1742                 atomic_read(&osc->oo_nr_reads) > 0);
1743
1744         return osc_is_ready(osc);
1745 }
1746
1747 static int osc_list_maint(struct client_obd *cli, struct osc_object *osc)
1748 {
1749         int is_ready;
1750
1751         spin_lock(&cli->cl_loi_list_lock);
1752         is_ready = __osc_list_maint(cli, osc);
1753         spin_unlock(&cli->cl_loi_list_lock);
1754
1755         return is_ready;
1756 }
1757
1758 /* this is trying to propogate async writeback errors back up to the
1759  * application.  As an async write fails we record the error code for later if
1760  * the app does an fsync.  As long as errors persist we force future rpcs to be
1761  * sync so that the app can get a sync error and break the cycle of queueing
1762  * pages for which writeback will fail. */
1763 static void osc_process_ar(struct osc_async_rc *ar, __u64 xid,
1764                            int rc)
1765 {
1766         if (rc) {
1767                 if (!ar->ar_rc)
1768                         ar->ar_rc = rc;
1769
1770                 ar->ar_force_sync = 1;
1771                 ar->ar_min_xid = ptlrpc_sample_next_xid();
1772                 return;
1773
1774         }
1775
1776         if (ar->ar_force_sync && (xid >= ar->ar_min_xid))
1777                 ar->ar_force_sync = 0;
1778 }
1779
1780 /* this must be called holding the loi list lock to give coverage to exit_cache,
1781  * async_flag maintenance, and oap_request */
1782 static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
1783                               struct osc_async_page *oap, int sent, int rc)
1784 {
1785         struct osc_object *osc = oap->oap_obj;
1786         struct lov_oinfo  *loi = osc->oo_oinfo;
1787         __u64 xid = 0;
1788
1789         ENTRY;
1790         if (oap->oap_request != NULL) {
1791                 xid = ptlrpc_req_xid(oap->oap_request);
1792                 ptlrpc_req_finished(oap->oap_request);
1793                 oap->oap_request = NULL;
1794         }
1795
1796         /* As the transfer for this page is being done, clear the flags */
1797         spin_lock(&oap->oap_lock);
1798         oap->oap_async_flags = 0;
1799         spin_unlock(&oap->oap_lock);
1800
1801         if (oap->oap_cmd & OBD_BRW_WRITE && xid > 0) {
1802                 spin_lock(&cli->cl_loi_list_lock);
1803                 osc_process_ar(&cli->cl_ar, xid, rc);
1804                 osc_process_ar(&loi->loi_ar, xid, rc);
1805                 spin_unlock(&cli->cl_loi_list_lock);
1806         }
1807
1808         rc = osc_completion(env, oap, oap->oap_cmd, rc);
1809         if (rc)
1810                 CERROR("completion on oap %p obj %p returns %d.\n",
1811                        oap, osc, rc);
1812
1813         EXIT;
1814 }
1815
1816 struct extent_rpc_data {
1817         struct list_head        *erd_rpc_list;
1818         unsigned int            erd_page_count;
1819         unsigned int            erd_max_pages;
1820         unsigned int            erd_max_chunks;
1821         unsigned int            erd_max_extents;
1822 };
1823
1824 static inline unsigned osc_extent_chunks(const struct osc_extent *ext)
1825 {
1826         struct client_obd *cli = osc_cli(ext->oe_obj);
1827         unsigned ppc_bits = cli->cl_chunkbits - PAGE_SHIFT;
1828
1829         return (ext->oe_end >> ppc_bits) - (ext->oe_start >> ppc_bits) + 1;
1830 }
1831
1832 static inline bool
1833 can_merge(const struct osc_extent *ext, const struct osc_extent *in_rpc)
1834 {
1835         if (ext->oe_no_merge || in_rpc->oe_no_merge)
1836                 return false;
1837
1838         if (ext->oe_srvlock != in_rpc->oe_srvlock)
1839                 return false;
1840
1841         if (ext->oe_ndelay != in_rpc->oe_ndelay)
1842                 return false;
1843
1844         if (!ext->oe_grants != !in_rpc->oe_grants)
1845                 return false;
1846
1847         if (ext->oe_dio != in_rpc->oe_dio)
1848                 return false;
1849
1850         /* It's possible to have overlap on DIO */
1851         if (in_rpc->oe_dio && overlapped(ext, in_rpc))
1852                 return false;
1853
1854         if (ext->oe_is_rdma_only != in_rpc->oe_is_rdma_only)
1855                 return false;
1856
1857         return true;
1858 }
1859
1860 /**
1861  * Try to add extent to one RPC. We need to think about the following things:
1862  * - # of pages must not be over max_pages_per_rpc
1863  * - extent must be compatible with previous ones
1864  */
1865 static int try_to_add_extent_for_io(struct client_obd *cli,
1866                                     struct osc_extent *ext,
1867                                     struct extent_rpc_data *data)
1868 {
1869         struct osc_extent *tmp;
1870         unsigned int chunk_count;
1871         ENTRY;
1872
1873         EASSERT((ext->oe_state == OES_CACHE || ext->oe_state == OES_LOCK_DONE),
1874                 ext);
1875         OSC_EXTENT_DUMP(D_CACHE, ext, "trying to add this extent\n");
1876
1877         if (data->erd_max_extents == 0)
1878                 RETURN(0);
1879
1880         chunk_count = osc_extent_chunks(ext);
1881         EASSERTF(data->erd_page_count != 0 ||
1882                  chunk_count <= data->erd_max_chunks, ext,
1883                  "The first extent to be fit in a RPC contains %u chunks, "
1884                  "which is over the limit %u.\n", chunk_count,
1885                  data->erd_max_chunks);
1886         if (chunk_count > data->erd_max_chunks)
1887                 RETURN(0);
1888
1889         data->erd_max_pages = max(ext->oe_mppr, data->erd_max_pages);
1890         EASSERTF(data->erd_page_count != 0 ||
1891                 ext->oe_nr_pages <= data->erd_max_pages, ext,
1892                 "The first extent to be fit in a RPC contains %u pages, "
1893                 "which is over the limit %u.\n", ext->oe_nr_pages,
1894                 data->erd_max_pages);
1895         if (data->erd_page_count + ext->oe_nr_pages > data->erd_max_pages)
1896                 RETURN(0);
1897
1898         list_for_each_entry(tmp, data->erd_rpc_list, oe_link) {
1899                 EASSERT(tmp->oe_owner == current, tmp);
1900
1901                 if (!can_merge(ext, tmp))
1902                         RETURN(0);
1903         }
1904
1905         data->erd_max_extents--;
1906         data->erd_max_chunks -= chunk_count;
1907         data->erd_page_count += ext->oe_nr_pages;
1908         list_move_tail(&ext->oe_link, data->erd_rpc_list);
1909         ext->oe_owner = current;
1910         RETURN(1);
1911 }
1912
1913 /**
1914  * In order to prevent multiple ptlrpcd from breaking contiguous extents,
1915  * get_write_extent() takes all appropriate extents in atomic.
1916  *
1917  * The following policy is used to collect extents for IO:
1918  * 1. Add as many HP extents as possible;
1919  * 2. Add the first urgent extent in urgent extent list and take it out of
1920  *    urgent list;
1921  * 3. Add subsequent extents of this urgent extent;
1922  * 4. If urgent list is not empty, goto 2;
1923  * 5. Traverse the extent tree from the 1st extent;
1924  * 6. Above steps exit if there is no space in this RPC.
1925  */
1926 static unsigned int get_write_extents(struct osc_object *obj,
1927                                       struct list_head *rpclist)
1928 {
1929         struct client_obd *cli = osc_cli(obj);
1930         struct osc_extent *ext;
1931         struct extent_rpc_data data = {
1932                 .erd_rpc_list   = rpclist,
1933                 .erd_page_count = 0,
1934                 .erd_max_pages  = cli->cl_max_pages_per_rpc,
1935                 .erd_max_chunks = osc_max_write_chunks(cli),
1936                 .erd_max_extents = 256,
1937         };
1938
1939         assert_osc_object_is_locked(obj);
1940         while (!list_empty(&obj->oo_hp_exts)) {
1941                 ext = list_entry(obj->oo_hp_exts.next, struct osc_extent,
1942                                  oe_link);
1943                 if (!try_to_add_extent_for_io(cli, ext, &data))
1944                         return data.erd_page_count;
1945                 EASSERT(ext->oe_nr_pages <= data.erd_max_pages, ext);
1946         }
1947         if (data.erd_page_count == data.erd_max_pages)
1948                 return data.erd_page_count;
1949
1950         while (!list_empty(&obj->oo_urgent_exts)) {
1951                 ext = list_entry(obj->oo_urgent_exts.next,
1952                                  struct osc_extent, oe_link);
1953                 if (!try_to_add_extent_for_io(cli, ext, &data))
1954                         return data.erd_page_count;
1955         }
1956         if (data.erd_page_count == data.erd_max_pages)
1957                 return data.erd_page_count;
1958
1959         /* One key difference between full extents and other extents: full
1960          * extents can usually only be added if the rpclist was empty, so if we
1961          * can't add one, we continue on to trying to add normal extents.  This
1962          * is so we don't miss adding extra extents to an RPC containing high
1963          * priority or urgent extents. */
1964         while (!list_empty(&obj->oo_full_exts)) {
1965                 ext = list_entry(obj->oo_full_exts.next,
1966                                  struct osc_extent, oe_link);
1967                 if (!try_to_add_extent_for_io(cli, ext, &data))
1968                         break;
1969         }
1970         if (data.erd_page_count == data.erd_max_pages)
1971                 return data.erd_page_count;
1972
1973         for (ext = first_extent(obj);
1974              ext;
1975              ext = next_extent(ext)) {
1976                 if ((ext->oe_state != OES_CACHE) ||
1977                     /* this extent may be already in current rpclist */
1978                     (!list_empty(&ext->oe_link) && ext->oe_owner))
1979                         continue;
1980
1981                 if (!try_to_add_extent_for_io(cli, ext, &data))
1982                         return data.erd_page_count;
1983         }
1984         return data.erd_page_count;
1985 }
1986
1987 static int
1988 osc_send_write_rpc(const struct lu_env *env, struct client_obd *cli,
1989                    struct osc_object *osc)
1990 __must_hold(osc)
1991 {
1992         LIST_HEAD(rpclist);
1993         struct osc_extent *ext;
1994         struct osc_extent *tmp;
1995         struct osc_extent *first = NULL;
1996         unsigned int page_count = 0;
1997         int srvlock = 0;
1998         int rc = 0;
1999         ENTRY;
2000
2001         assert_osc_object_is_locked(osc);
2002
2003         page_count = get_write_extents(osc, &rpclist);
2004         LASSERT(equi(page_count == 0, list_empty(&rpclist)));
2005
2006         if (list_empty(&rpclist))
2007                 RETURN(0);
2008
2009         osc_update_pending(osc, OBD_BRW_WRITE, -page_count);
2010
2011         list_for_each_entry(ext, &rpclist, oe_link) {
2012                 LASSERT(ext->oe_state == OES_CACHE ||
2013                         ext->oe_state == OES_LOCK_DONE);
2014                 if (ext->oe_state == OES_CACHE)
2015                         osc_extent_state_set(ext, OES_LOCKING);
2016                 else
2017                         osc_extent_state_set(ext, OES_RPC);
2018         }
2019
2020         /* we're going to grab page lock, so release object lock because
2021          * lock order is page lock -> object lock. */
2022         osc_object_unlock(osc);
2023
2024         list_for_each_entry_safe(ext, tmp, &rpclist, oe_link) {
2025                 if (ext->oe_state == OES_LOCKING) {
2026                         rc = osc_extent_make_ready(env, ext);
2027                         if (unlikely(rc < 0)) {
2028                                 list_del_init(&ext->oe_link);
2029                                 osc_extent_finish(env, ext, 0, rc);
2030                                 continue;
2031                         }
2032                 }
2033                 if (first == NULL) {
2034                         first = ext;
2035                         srvlock = ext->oe_srvlock;
2036                 } else {
2037                         LASSERT(srvlock == ext->oe_srvlock);
2038                 }
2039         }
2040
2041         if (!list_empty(&rpclist)) {
2042                 LASSERT(page_count > 0);
2043                 rc = osc_build_rpc(env, cli, &rpclist, OBD_BRW_WRITE);
2044                 LASSERT(list_empty(&rpclist));
2045         }
2046
2047         osc_object_lock(osc);
2048         RETURN(rc);
2049 }
2050
2051 /**
2052  * prepare pages for ASYNC io and put pages in send queue.
2053  *
2054  * \param cmd OBD_BRW_* macroses
2055  * \param lop pending pages
2056  *
2057  * \return zero if no page added to send queue.
2058  * \return 1 if pages successfully added to send queue.
2059  * \return negative on errors.
2060  */
2061 static int
2062 osc_send_read_rpc(const struct lu_env *env, struct client_obd *cli,
2063                   struct osc_object *osc)
2064 __must_hold(osc)
2065 {
2066         struct osc_extent *ext;
2067         struct osc_extent *next;
2068         LIST_HEAD(rpclist);
2069         struct extent_rpc_data data = {
2070                 .erd_rpc_list   = &rpclist,
2071                 .erd_page_count = 0,
2072                 .erd_max_pages  = cli->cl_max_pages_per_rpc,
2073                 .erd_max_chunks = UINT_MAX,
2074                 .erd_max_extents = UINT_MAX,
2075         };
2076         int rc = 0;
2077         ENTRY;
2078
2079         assert_osc_object_is_locked(osc);
2080         list_for_each_entry_safe(ext, next, &osc->oo_reading_exts, oe_link) {
2081                 EASSERT(ext->oe_state == OES_LOCK_DONE, ext);
2082                 if (!try_to_add_extent_for_io(cli, ext, &data))
2083                         break;
2084                 osc_extent_state_set(ext, OES_RPC);
2085                 EASSERT(ext->oe_nr_pages <= data.erd_max_pages, ext);
2086         }
2087         LASSERT(data.erd_page_count <= data.erd_max_pages);
2088
2089         osc_update_pending(osc, OBD_BRW_READ, -data.erd_page_count);
2090
2091         if (!list_empty(&rpclist)) {
2092                 osc_object_unlock(osc);
2093
2094                 rc = osc_build_rpc(env, cli, &rpclist, OBD_BRW_READ);
2095                 LASSERT(list_empty(&rpclist));
2096
2097                 osc_object_lock(osc);
2098         }
2099         RETURN(rc);
2100 }
2101
2102 #define list_to_obj(list, item) ({                                            \
2103         struct list_head *__tmp = (list)->next;                               \
2104         list_del_init(__tmp);                                         \
2105         list_entry(__tmp, struct osc_object, oo_##item);                      \
2106 })
2107
2108 /* This is called by osc_check_rpcs() to find which objects have pages that
2109  * we could be sending.  These lists are maintained by osc_makes_rpc(). */
2110 static struct osc_object *osc_next_obj(struct client_obd *cli)
2111 {
2112         ENTRY;
2113
2114         /* First return objects that have blocked locks so that they
2115          * will be flushed quickly and other clients can get the lock,
2116          * then objects which have pages ready to be stuffed into RPCs */
2117         if (!list_empty(&cli->cl_loi_hp_ready_list))
2118                 RETURN(list_to_obj(&cli->cl_loi_hp_ready_list, hp_ready_item));
2119         if (!list_empty(&cli->cl_loi_ready_list))
2120                 RETURN(list_to_obj(&cli->cl_loi_ready_list, ready_item));
2121
2122         /* then if we have cache waiters, return all objects with queued
2123          * writes.  This is especially important when many small files
2124          * have filled up the cache and not been fired into rpcs because
2125          * they don't pass the nr_pending/object threshhold
2126          */
2127         if (waitqueue_active(&cli->cl_cache_waiters) &&
2128             !list_empty(&cli->cl_loi_write_list))
2129                 RETURN(list_to_obj(&cli->cl_loi_write_list, write_item));
2130
2131         /* then return all queued objects when we have an invalid import
2132          * so that they get flushed */
2133         if (cli->cl_import == NULL || cli->cl_import->imp_invalid) {
2134                 if (!list_empty(&cli->cl_loi_write_list))
2135                         RETURN(list_to_obj(&cli->cl_loi_write_list,
2136                                            write_item));
2137                 if (!list_empty(&cli->cl_loi_read_list))
2138                         RETURN(list_to_obj(&cli->cl_loi_read_list,
2139                                            read_item));
2140         }
2141         RETURN(NULL);
2142 }
2143
2144 /* called with the loi list lock held */
2145 static void osc_check_rpcs(const struct lu_env *env, struct client_obd *cli)
2146 __must_hold(&cli->cl_loi_list_lock)
2147 {
2148         struct osc_object *osc;
2149         int rc = 0;
2150         ENTRY;
2151
2152         while ((osc = osc_next_obj(cli)) != NULL) {
2153                 struct cl_object *obj = osc2cl(osc);
2154                 struct lu_ref_link link;
2155
2156                 OSC_IO_DEBUG(osc, "%lu in flight\n", rpcs_in_flight(cli));
2157
2158                 /* even if we have reached our max in flight RPCs, we still
2159                  * allow all high-priority RPCs through to prevent their
2160                  * starvation and leading to server evicting us for not
2161                  * writing out pages in a timely manner LU-13131 */
2162                 if (osc_max_rpc_in_flight(cli, osc) &&
2163                     list_empty(&osc->oo_hp_exts)) {
2164                         __osc_list_maint(cli, osc);
2165                         break;
2166                 }
2167
2168                 cl_object_get(obj);
2169                 spin_unlock(&cli->cl_loi_list_lock);
2170                 lu_object_ref_add_at(&obj->co_lu, &link, "check", current);
2171
2172                 /* attempt some read/write balancing by alternating between
2173                  * reads and writes in an object.  The makes_rpc checks here
2174                  * would be redundant if we were getting read/write work items
2175                  * instead of objects.  we don't want send_oap_rpc to drain a
2176                  * partial read pending queue when we're given this object to
2177                  * do io on writes while there are cache waiters */
2178                 osc_object_lock(osc);
2179                 if (osc_makes_rpc(cli, osc, OBD_BRW_WRITE)) {
2180                         rc = osc_send_write_rpc(env, cli, osc);
2181                         if (rc < 0) {
2182                                 CERROR("Write request failed with %d\n", rc);
2183
2184                                 /* osc_send_write_rpc failed, mostly because of
2185                                  * memory pressure.
2186                                  *
2187                                  * It can't break here, because if:
2188                                  *  - a page was submitted by osc_io_submit, so
2189                                  *    page locked;
2190                                  *  - no request in flight
2191                                  *  - no subsequent request
2192                                  * The system will be in live-lock state,
2193                                  * because there is no chance to call
2194                                  * osc_io_unplug() and osc_check_rpcs() any
2195                                  * more. pdflush can't help in this case,
2196                                  * because it might be blocked at grabbing
2197                                  * the page lock as we mentioned.
2198                                  *
2199                                  * Anyway, continue to drain pages. */
2200                                 /* break; */
2201                         }
2202                 }
2203                 if (osc_makes_rpc(cli, osc, OBD_BRW_READ)) {
2204                         rc = osc_send_read_rpc(env, cli, osc);
2205                         if (rc < 0)
2206                                 CERROR("Read request failed with %d\n", rc);
2207                 }
2208                 osc_object_unlock(osc);
2209
2210                 osc_list_maint(cli, osc);
2211                 lu_object_ref_del_at(&obj->co_lu, &link, "check", current);
2212                 cl_object_put(env, obj);
2213
2214                 spin_lock(&cli->cl_loi_list_lock);
2215         }
2216 }
2217
2218 int osc_io_unplug0(const struct lu_env *env, struct client_obd *cli,
2219                    struct osc_object *osc, int async)
2220 {
2221         int rc = 0;
2222
2223         if (osc != NULL && osc_list_maint(cli, osc) == 0)
2224                 return 0;
2225
2226         if (!async) {
2227                 spin_lock(&cli->cl_loi_list_lock);
2228                 osc_check_rpcs(env, cli);
2229                 spin_unlock(&cli->cl_loi_list_lock);
2230         } else {
2231                 CDEBUG(D_CACHE, "Queue writeback work for client %p.\n", cli);
2232                 LASSERT(cli->cl_writeback_work != NULL);
2233                 rc = ptlrpcd_queue_work(cli->cl_writeback_work);
2234         }
2235         return rc;
2236 }
2237 EXPORT_SYMBOL(osc_io_unplug0);
2238
2239 int osc_prep_async_page(struct osc_object *osc, struct osc_page *ops,
2240                         struct page *page, loff_t offset)
2241 {
2242         struct obd_export     *exp = osc_export(osc);
2243         struct osc_async_page *oap = &ops->ops_oap;
2244         ENTRY;
2245
2246         if (!page)
2247                 return cfs_size_round(sizeof(*oap));
2248
2249         oap->oap_magic = OAP_MAGIC;
2250         oap->oap_cli = &exp->exp_obd->u.cli;
2251         oap->oap_obj = osc;
2252
2253         oap->oap_page = page;
2254         oap->oap_obj_off = offset;
2255         LASSERT(!(offset & ~PAGE_MASK));
2256
2257         INIT_LIST_HEAD(&oap->oap_pending_item);
2258         INIT_LIST_HEAD(&oap->oap_rpc_item);
2259
2260         spin_lock_init(&oap->oap_lock);
2261         CDEBUG(D_INFO, "oap %p page %p obj off %llu\n",
2262                oap, page, oap->oap_obj_off);
2263         RETURN(0);
2264 }
2265 EXPORT_SYMBOL(osc_prep_async_page);
2266
2267 int osc_queue_async_io(const struct lu_env *env, struct cl_io *io,
2268                        struct osc_page *ops, cl_commit_cbt cb)
2269 {
2270         struct osc_io *oio = osc_env_io(env);
2271         struct osc_extent     *ext = NULL;
2272         struct osc_async_page *oap = &ops->ops_oap;
2273         struct client_obd     *cli = oap->oap_cli;
2274         struct osc_object     *osc = oap->oap_obj;
2275         struct pagevec        *pvec = &osc_env_info(env)->oti_pagevec;
2276         pgoff_t index;
2277         unsigned int tmp;
2278         unsigned int grants = 0;
2279         u32    brw_flags = OBD_BRW_ASYNC;
2280         int    cmd = OBD_BRW_WRITE;
2281         int    need_release = 0;
2282         int    rc = 0;
2283         ENTRY;
2284
2285         if (oap->oap_magic != OAP_MAGIC)
2286                 RETURN(-EINVAL);
2287
2288         if (cli->cl_import == NULL || cli->cl_import->imp_invalid)
2289                 RETURN(-EIO);
2290
2291         if (!list_empty(&oap->oap_pending_item) ||
2292             !list_empty(&oap->oap_rpc_item))
2293                 RETURN(-EBUSY);
2294
2295         /* Set the OBD_BRW_SRVLOCK before the page is queued. */
2296         brw_flags |= ops->ops_srvlock ? OBD_BRW_SRVLOCK : 0;
2297         if (oio->oi_cap_sys_resource || io->ci_noquota) {
2298                 brw_flags |= OBD_BRW_NOQUOTA;
2299                 cmd |= OBD_BRW_NOQUOTA;
2300         }
2301
2302         /* check if the file's owner/group is over quota */
2303         if (!(cmd & OBD_BRW_NOQUOTA)) {
2304                 struct cl_object *obj;
2305                 struct cl_attr   *attr;
2306                 unsigned int qid[LL_MAXQUOTAS];
2307
2308                 obj = cl_object_top(&osc->oo_cl);
2309                 attr = &osc_env_info(env)->oti_attr;
2310
2311                 cl_object_attr_lock(obj);
2312                 rc = cl_object_attr_get(env, obj, attr);
2313                 cl_object_attr_unlock(obj);
2314
2315                 qid[USRQUOTA] = attr->cat_uid;
2316                 qid[GRPQUOTA] = attr->cat_gid;
2317                 qid[PRJQUOTA] = attr->cat_projid;
2318                 if (rc == 0 && osc_quota_chkdq(cli, qid) == -EDQUOT)
2319                         rc = -EDQUOT;
2320                 if (rc)
2321                         RETURN(rc);
2322         }
2323
2324         oap->oap_cmd = cmd;
2325         oap->oap_page_off = ops->ops_from;
2326         oap->oap_count = ops->ops_to - ops->ops_from;
2327         /* No need to hold a lock here,
2328          * since this page is not in any list yet. */
2329         oap->oap_async_flags = 0;
2330         oap->oap_brw_flags = brw_flags;
2331
2332         OSC_IO_DEBUG(osc, "oap %p page %p added for cmd %d\n",
2333                      oap, oap->oap_page, oap->oap_cmd & OBD_BRW_RWMASK);
2334
2335         index = osc_index(oap2osc(oap));
2336
2337         /* Add this page into extent by the following steps:
2338          * 1. if there exists an active extent for this IO, mostly this page
2339          *    can be added to the active extent and sometimes we need to
2340          *    expand extent to accomodate this page;
2341          * 2. otherwise, a new extent will be allocated. */
2342
2343         ext = oio->oi_active;
2344         if (ext != NULL && ext->oe_start <= index && ext->oe_max_end >= index) {
2345                 /* one chunk plus extent overhead must be enough to write this
2346                  * page */
2347                 grants = (1 << cli->cl_chunkbits) + cli->cl_grant_extent_tax;
2348                 if (ext->oe_end >= index)
2349                         grants = 0;
2350
2351                 /* it doesn't need any grant to dirty this page */
2352                 spin_lock(&cli->cl_loi_list_lock);
2353                 rc = osc_enter_cache_try(cli, oap, grants);
2354                 if (rc == 0) { /* try failed */
2355                         grants = 0;
2356                         need_release = 1;
2357                 } else if (ext->oe_end < index) {
2358                         tmp = grants;
2359                         /* try to expand this extent */
2360                         rc = osc_extent_expand(ext, index, &tmp);
2361                         if (rc < 0) {
2362                                 need_release = 1;
2363                                 /* don't free reserved grant */
2364                         } else {
2365                                 OSC_EXTENT_DUMP(D_CACHE, ext,
2366                                                 "expanded for %lu.\n", index);
2367                                 osc_unreserve_grant_nolock(cli, grants, tmp);
2368                                 grants = 0;
2369                         }
2370                 }
2371                 spin_unlock(&cli->cl_loi_list_lock);
2372                 rc = 0;
2373         } else if (ext != NULL) {
2374                 /* index is located outside of active extent */
2375                 need_release = 1;
2376         }
2377         if (need_release) {
2378                 osc_extent_release(env, ext);
2379                 oio->oi_active = NULL;
2380                 ext = NULL;
2381         }
2382
2383         if (ext == NULL) {
2384                 tmp = (1 << cli->cl_chunkbits) + cli->cl_grant_extent_tax;
2385
2386                 /* try to find new extent to cover this page */
2387                 LASSERT(oio->oi_active == NULL);
2388                 /* we may have allocated grant for this page if we failed
2389                  * to expand the previous active extent. */
2390                 LASSERT(ergo(grants > 0, grants >= tmp));
2391
2392                 rc = 0;
2393                 if (grants == 0) {
2394                         /* We haven't allocated grant for this page, and we
2395                          * must not hold a page lock while we do enter_cache,
2396                          * so we must mark dirty & unlock any pages in the
2397                          * write commit pagevec. */
2398                         if (pagevec_count(pvec)) {
2399                                 cb(env, io, pvec);
2400                                 pagevec_reinit(pvec);
2401                         }
2402                         rc = osc_enter_cache(env, cli, oap, tmp);
2403                         if (rc == 0)
2404                                 grants = tmp;
2405                 }
2406
2407                 tmp = grants;
2408                 if (rc == 0) {
2409                         ext = osc_extent_find(env, osc, index, &tmp);
2410                         if (IS_ERR(ext)) {
2411                                 LASSERT(tmp == grants);
2412                                 osc_exit_cache(cli, oap);
2413                                 rc = PTR_ERR(ext);
2414                                 ext = NULL;
2415                         } else {
2416                                 oio->oi_active = ext;
2417                         }
2418                 }
2419                 if (grants > 0)
2420                         osc_unreserve_grant(cli, grants, tmp);
2421         }
2422
2423         LASSERT(ergo(rc == 0, ext != NULL));
2424         if (ext != NULL) {
2425                 EASSERTF(ext->oe_end >= index && ext->oe_start <= index,
2426                          ext, "index = %lu.\n", index);
2427                 LASSERT((oap->oap_brw_flags & OBD_BRW_FROM_GRANT) != 0);
2428
2429                 osc_object_lock(osc);
2430                 if (ext->oe_nr_pages == 0)
2431                         ext->oe_srvlock = ops->ops_srvlock;
2432                 else
2433                         LASSERT(ext->oe_srvlock == ops->ops_srvlock);
2434                 ++ext->oe_nr_pages;
2435                 list_add_tail(&oap->oap_pending_item, &ext->oe_pages);
2436                 osc_object_unlock(osc);
2437
2438                 if (!ext->oe_layout_version)
2439                         ext->oe_layout_version = io->ci_layout_version;
2440         }
2441
2442         RETURN(rc);
2443 }
2444
2445 int osc_teardown_async_page(const struct lu_env *env,
2446                             struct osc_object *obj, struct osc_page *ops)
2447 {
2448         struct osc_async_page *oap = &ops->ops_oap;
2449         int rc = 0;
2450         ENTRY;
2451
2452         LASSERT(oap->oap_magic == OAP_MAGIC);
2453
2454         CDEBUG(D_INFO, "teardown oap %p page %p at index %lu.\n",
2455                oap, ops, osc_index(oap2osc(oap)));
2456
2457         if (!list_empty(&oap->oap_rpc_item)) {
2458                 CDEBUG(D_CACHE, "oap %p is not in cache.\n", oap);
2459                 rc = -EBUSY;
2460         } else if (!list_empty(&oap->oap_pending_item)) {
2461                 struct osc_extent *ext = NULL;
2462
2463                 osc_object_lock(obj);
2464                 ext = osc_extent_lookup(obj, osc_index(oap2osc(oap)));
2465                 osc_object_unlock(obj);
2466                 /* only truncated pages are allowed to be taken out.
2467                  * See osc_extent_truncate() and osc_cache_truncate_start()
2468                  * for details. */
2469                 if (ext != NULL && ext->oe_state != OES_TRUNC) {
2470                         OSC_EXTENT_DUMP(D_ERROR, ext, "trunc at %lu.\n",
2471                                         osc_index(oap2osc(oap)));
2472                         rc = -EBUSY;
2473                 }
2474                 if (ext != NULL)
2475                         osc_extent_put(env, ext);
2476         }
2477         RETURN(rc);
2478 }
2479
2480 /**
2481  * This is called when a page is picked up by kernel to write out.
2482  *
2483  * We should find out the corresponding extent and add the whole extent
2484  * into urgent list. The extent may be being truncated or used, handle it
2485  * carefully.
2486  */
2487 int osc_flush_async_page(const struct lu_env *env, struct cl_io *io,
2488                          struct osc_page *ops)
2489 {
2490         struct osc_extent *ext   = NULL;
2491         struct osc_object *obj   = cl2osc(ops->ops_cl.cpl_obj);
2492         struct cl_page    *cp    = ops->ops_cl.cpl_page;
2493         pgoff_t            index = osc_index(ops);
2494         struct osc_async_page *oap = &ops->ops_oap;
2495         bool unplug = false;
2496         int rc = 0;
2497         ENTRY;
2498
2499         osc_object_lock(obj);
2500         ext = osc_extent_lookup(obj, index);
2501         if (ext == NULL) {
2502                 osc_extent_tree_dump(D_ERROR, obj);
2503                 LASSERTF(0, "page index %lu is NOT covered.\n", index);
2504         }
2505
2506         switch (ext->oe_state) {
2507         case OES_RPC:
2508         case OES_LOCK_DONE:
2509                 CL_PAGE_DEBUG(D_ERROR, env, cp, "flush an in-rpc page?\n");
2510                 LASSERT(0);
2511                 break;
2512         case OES_LOCKING:
2513                 /* If we know this extent is being written out, we should abort
2514                  * so that the writer can make this page ready. Otherwise, there
2515                  * exists a deadlock problem because other process can wait for
2516                  * page writeback bit holding page lock; and meanwhile in
2517                  * vvp_page_make_ready(), we need to grab page lock before
2518                  * really sending the RPC. */
2519         case OES_TRUNC:
2520                 /* race with truncate, page will be redirtied */
2521         case OES_ACTIVE:
2522                 /* The extent is active so we need to abort and let the caller
2523                  * re-dirty the page. If we continued on here, and we were the
2524                  * one making the extent active, we could deadlock waiting for
2525                  * the page writeback to clear but it won't because the extent
2526                  * is active and won't be written out. */
2527                 GOTO(out, rc = -EAGAIN);
2528         default:
2529                 break;
2530         }
2531
2532         rc = cl_page_prep(env, io, cp, CRT_WRITE);
2533         if (rc)
2534                 GOTO(out, rc);
2535
2536         spin_lock(&oap->oap_lock);
2537         oap->oap_async_flags |= ASYNC_READY|ASYNC_URGENT;
2538         spin_unlock(&oap->oap_lock);
2539
2540         if (current->flags & PF_MEMALLOC)
2541                 ext->oe_memalloc = 1;
2542
2543         ext->oe_urgent = 1;
2544         if (ext->oe_state == OES_CACHE) {
2545                 OSC_EXTENT_DUMP(D_CACHE, ext,
2546                                 "flush page %p make it urgent.\n", oap);
2547                 if (list_empty(&ext->oe_link))
2548                         list_add_tail(&ext->oe_link, &obj->oo_urgent_exts);
2549                 unplug = true;
2550         }
2551         rc = 0;
2552         EXIT;
2553
2554 out:
2555         osc_object_unlock(obj);
2556         osc_extent_put(env, ext);
2557         if (unplug)
2558                 osc_io_unplug_async(env, osc_cli(obj), obj);
2559         return rc;
2560 }
2561
2562 int osc_queue_sync_pages(const struct lu_env *env, const struct cl_io *io,
2563                          struct osc_object *obj, struct list_head *list,
2564                          int brw_flags)
2565 {
2566         struct client_obd     *cli = osc_cli(obj);
2567         struct osc_extent     *ext;
2568         struct osc_async_page *oap;
2569         int     page_count = 0;
2570         int     mppr       = cli->cl_max_pages_per_rpc;
2571         bool    can_merge   = true;
2572         pgoff_t start      = CL_PAGE_EOF;
2573         pgoff_t end        = 0;
2574         ENTRY;
2575
2576         list_for_each_entry(oap, list, oap_pending_item) {
2577                 struct osc_page *opg = oap2osc_page(oap);
2578                 pgoff_t index = osc_index(opg);
2579
2580                 if (index > end)
2581                         end = index;
2582                 if (index < start)
2583                         start = index;
2584                 ++page_count;
2585                 mppr <<= (page_count > mppr);
2586
2587                 if (unlikely(opg->ops_from > 0 || opg->ops_to < PAGE_SIZE))
2588                         can_merge = false;
2589         }
2590
2591         ext = osc_extent_alloc(obj);
2592         if (ext == NULL) {
2593                 struct osc_async_page *tmp;
2594
2595                 list_for_each_entry_safe(oap, tmp, list, oap_pending_item) {
2596                         list_del_init(&oap->oap_pending_item);
2597                         osc_ap_completion(env, cli, oap, 0, -ENOMEM);
2598                 }
2599                 RETURN(-ENOMEM);
2600         }
2601
2602         ext->oe_rw = !!(brw_flags & OBD_BRW_READ);
2603         ext->oe_sync = 1;
2604         ext->oe_no_merge = !can_merge;
2605         ext->oe_urgent = 1;
2606         ext->oe_start = start;
2607         ext->oe_end = ext->oe_max_end = end;
2608         ext->oe_obj = obj;
2609         ext->oe_srvlock = !!(brw_flags & OBD_BRW_SRVLOCK);
2610         ext->oe_ndelay = !!(brw_flags & OBD_BRW_NDELAY);
2611         ext->oe_dio = !!(brw_flags & OBD_BRW_NOCACHE);
2612         ext->oe_is_rdma_only = !!(brw_flags & OBD_BRW_RDMA_ONLY);
2613         ext->oe_nr_pages = page_count;
2614         ext->oe_mppr = mppr;
2615         list_splice_init(list, &ext->oe_pages);
2616         ext->oe_layout_version = io->ci_layout_version;
2617
2618         osc_object_lock(obj);
2619         /* Reuse the initial refcount for RPC, don't drop it */
2620         osc_extent_state_set(ext, OES_LOCK_DONE);
2621         if (!ext->oe_rw) { /* write */
2622                 if (!ext->oe_srvlock && !ext->oe_dio) {
2623                         /* The most likely case here is from lack of grants
2624                          * so we are either out of quota or out of space.
2625                          * Since this means we are holding locks across
2626                          * potentially multi-striped IO, we must send out
2627                          * everything out instantly to avoid prolonged
2628                          * waits resulting in lock eviction (likely since
2629                          * the extended wait in osc_cache_enter() did not
2630                          * yield any additional grant due to a timeout.
2631                          * LU-13131 */
2632                         ext->oe_hp = 1;
2633                         list_add_tail(&ext->oe_link, &obj->oo_hp_exts);
2634                 } else {
2635                         list_add_tail(&ext->oe_link, &obj->oo_urgent_exts);
2636                 }
2637                 osc_update_pending(obj, OBD_BRW_WRITE, page_count);
2638         } else {
2639                 list_add_tail(&ext->oe_link, &obj->oo_reading_exts);
2640                 osc_update_pending(obj, OBD_BRW_READ, page_count);
2641         }
2642         osc_object_unlock(obj);
2643
2644         osc_io_unplug_async(env, cli, obj);
2645         RETURN(0);
2646 }
2647
2648 /**
2649  * Called by osc_io_setattr_start() to freeze and destroy covering extents.
2650  */
2651 int osc_cache_truncate_start(const struct lu_env *env, struct osc_object *obj,
2652                              __u64 size, struct osc_extent **extp)
2653 {
2654         struct client_obd *cli = osc_cli(obj);
2655         struct osc_extent *ext;
2656         struct osc_extent *waiting = NULL;
2657         pgoff_t index;
2658         LIST_HEAD(list);
2659         int result = 0;
2660         bool partial;
2661         ENTRY;
2662
2663         /* pages with index greater or equal to index will be truncated. */
2664         index = cl_index(osc2cl(obj), size);
2665         partial = size > cl_offset(osc2cl(obj), index);
2666
2667 again:
2668         osc_object_lock(obj);
2669         ext = osc_extent_search(obj, index);
2670         if (ext == NULL)
2671                 ext = first_extent(obj);
2672         else if (ext->oe_end < index)
2673                 ext = next_extent(ext);
2674         while (ext != NULL) {
2675                 EASSERT(ext->oe_state != OES_TRUNC, ext);
2676
2677                 if (ext->oe_state > OES_CACHE || ext->oe_urgent) {
2678                         /* if ext is in urgent state, it means there must exist
2679                          * a page already having been flushed by write_page().
2680                          * We have to wait for this extent because we can't
2681                          * truncate that page. */
2682                         OSC_EXTENT_DUMP(D_CACHE, ext,
2683                                         "waiting for busy extent\n");
2684                         waiting = osc_extent_get(ext);
2685                         break;
2686                 }
2687
2688                 OSC_EXTENT_DUMP(D_CACHE, ext, "try to trunc:%llu.\n", size);
2689
2690                 osc_extent_get(ext);
2691                 if (ext->oe_state == OES_ACTIVE) {
2692                         /* though we grab inode mutex for write path, but we
2693                          * release it before releasing extent(in osc_io_end()),
2694                          * so there is a race window that an extent is still
2695                          * in OES_ACTIVE when truncate starts. */
2696                         LASSERT(!ext->oe_trunc_pending);
2697                         ext->oe_trunc_pending = 1;
2698                 } else {
2699                         EASSERT(ext->oe_state == OES_CACHE, ext);
2700                         osc_extent_state_set(ext, OES_TRUNC);
2701                         osc_update_pending(obj, OBD_BRW_WRITE,
2702                                            -ext->oe_nr_pages);
2703                 }
2704                 /* This extent could be on the full extents list, that's OK */
2705                 EASSERT(!ext->oe_hp && !ext->oe_urgent, ext);
2706                 if (!list_empty(&ext->oe_link))
2707                         list_move_tail(&ext->oe_link, &list);
2708                 else
2709                         list_add_tail(&ext->oe_link, &list);
2710
2711                 ext = next_extent(ext);
2712         }
2713         osc_object_unlock(obj);
2714
2715         osc_list_maint(cli, obj);
2716
2717         while (!list_empty(&list)) {
2718                 int rc;
2719
2720                 ext = list_entry(list.next, struct osc_extent, oe_link);
2721                 list_del_init(&ext->oe_link);
2722
2723                 /* extent may be in OES_ACTIVE state because inode mutex
2724                  * is released before osc_io_end() in file write case */
2725                 if (ext->oe_state != OES_TRUNC)
2726                         osc_extent_wait(env, ext, OES_TRUNC);
2727
2728                 rc = osc_extent_truncate(ext, index, partial);
2729                 if (rc < 0) {
2730                         if (result == 0)
2731                                 result = rc;
2732
2733                         OSC_EXTENT_DUMP(D_ERROR, ext,
2734                                         "truncate error %d\n", rc);
2735                 } else if (ext->oe_nr_pages == 0) {
2736                         osc_extent_remove(ext);
2737                 } else {
2738                         /* this must be an overlapped extent which means only
2739                          * part of pages in this extent have been truncated.
2740                          */
2741                         EASSERTF(ext->oe_start <= index, ext,
2742                                  "trunc index = %lu/%d.\n", index, partial);
2743                         /* fix index to skip this partially truncated extent */
2744                         index = ext->oe_end + 1;
2745                         partial = false;
2746
2747                         /* we need to hold this extent in OES_TRUNC state so
2748                          * that no writeback will happen. This is to avoid
2749                          * BUG 17397.
2750                          * Only partial truncate can reach here, if @size is
2751                          * not zero, the caller should provide a valid @extp. */
2752                         LASSERT(*extp == NULL);
2753                         *extp = osc_extent_get(ext);
2754                         OSC_EXTENT_DUMP(D_CACHE, ext,
2755                                         "trunc at %llu\n", size);
2756                 }
2757                 osc_extent_put(env, ext);
2758         }
2759         if (waiting != NULL) {
2760                 int rc;
2761
2762                 /* ignore the result of osc_extent_wait the write initiator
2763                  * should take care of it. */
2764                 rc = osc_extent_wait(env, waiting, OES_INV);
2765                 if (rc < 0)
2766                         OSC_EXTENT_DUMP(D_CACHE, waiting, "error: %d.\n", rc);
2767
2768                 osc_extent_put(env, waiting);
2769                 waiting = NULL;
2770                 goto again;
2771         }
2772         RETURN(result);
2773 }
2774 EXPORT_SYMBOL(osc_cache_truncate_start);
2775
2776 /**
2777  * Called after osc_io_setattr_end to add oio->oi_trunc back to cache.
2778  */
2779 void osc_cache_truncate_end(const struct lu_env *env, struct osc_extent *ext)
2780 {
2781         if (ext != NULL) {
2782                 struct osc_object *obj = ext->oe_obj;
2783                 bool unplug = false;
2784
2785                 EASSERT(ext->oe_nr_pages > 0, ext);
2786                 EASSERT(ext->oe_state == OES_TRUNC, ext);
2787                 EASSERT(!ext->oe_urgent, ext);
2788
2789                 OSC_EXTENT_DUMP(D_CACHE, ext, "trunc -> cache.\n");
2790                 osc_object_lock(obj);
2791                 osc_extent_state_set(ext, OES_CACHE);
2792                 if (ext->oe_fsync_wait && !ext->oe_urgent) {
2793                         ext->oe_urgent = 1;
2794                         list_move_tail(&ext->oe_link, &obj->oo_urgent_exts);
2795                         unplug = true;
2796                 }
2797                 osc_update_pending(obj, OBD_BRW_WRITE, ext->oe_nr_pages);
2798                 osc_object_unlock(obj);
2799                 osc_extent_put(env, ext);
2800
2801                 if (unplug)
2802                         osc_io_unplug_async(env, osc_cli(obj), obj);
2803         }
2804 }
2805
2806 /**
2807  * Wait for extents in a specific range to be written out.
2808  * The caller must have called osc_cache_writeback_range() to issue IO
2809  * otherwise it will take a long time for this function to finish.
2810  *
2811  * Caller must hold inode_mutex , or cancel exclusive dlm lock so that
2812  * nobody else can dirty this range of file while we're waiting for
2813  * extents to be written.
2814  */
2815 int osc_cache_wait_range(const struct lu_env *env, struct osc_object *obj,
2816                          pgoff_t start, pgoff_t end)
2817 {
2818         struct osc_extent *ext;
2819         pgoff_t index = start;
2820         int     result = 0;
2821         ENTRY;
2822
2823 again:
2824         osc_object_lock(obj);
2825         ext = osc_extent_search(obj, index);
2826         if (ext == NULL)
2827                 ext = first_extent(obj);
2828         else if (ext->oe_end < index)
2829                 ext = next_extent(ext);
2830         while (ext != NULL) {
2831                 int rc;
2832
2833                 if (ext->oe_start > end)
2834                         break;
2835
2836                 if (!ext->oe_fsync_wait) {
2837                         ext = next_extent(ext);
2838                         continue;
2839                 }
2840
2841                 EASSERT(ergo(ext->oe_state == OES_CACHE,
2842                              ext->oe_hp || ext->oe_urgent), ext);
2843                 EASSERT(ergo(ext->oe_state == OES_ACTIVE,
2844                              !ext->oe_hp && ext->oe_urgent), ext);
2845
2846                 index = ext->oe_end + 1;
2847                 osc_extent_get(ext);
2848                 osc_object_unlock(obj);
2849
2850                 rc = osc_extent_wait(env, ext, OES_INV);
2851                 if (result == 0)
2852                         result = rc;
2853                 osc_extent_put(env, ext);
2854                 goto again;
2855         }
2856         osc_object_unlock(obj);
2857
2858         OSC_IO_DEBUG(obj, "sync file range.\n");
2859         RETURN(result);
2860 }
2861 EXPORT_SYMBOL(osc_cache_wait_range);
2862
2863 /**
2864  * Called to write out a range of osc object.
2865  *
2866  * @hp     : should be set this is caused by lock cancel;
2867  * @discard: is set if dirty pages should be dropped - file will be deleted or
2868  *         truncated, this implies there is no partially discarding extents.
2869  *
2870  * Return how many pages will be issued, or error code if error occurred.
2871  */
2872 int osc_cache_writeback_range(const struct lu_env *env, struct osc_object *obj,
2873                               pgoff_t start, pgoff_t end, int hp, int discard)
2874 {
2875         struct osc_extent *ext;
2876         LIST_HEAD(discard_list);
2877         bool unplug = false;
2878         int result = 0;
2879         ENTRY;
2880
2881         osc_object_lock(obj);
2882         ext = osc_extent_search(obj, start);
2883         if (ext == NULL)
2884                 ext = first_extent(obj);
2885         else if (ext->oe_end < start)
2886                 ext = next_extent(ext);
2887         while (ext != NULL) {
2888                 if (ext->oe_start > end)
2889                         break;
2890
2891                 ext->oe_fsync_wait = 1;
2892                 switch (ext->oe_state) {
2893                 case OES_CACHE:
2894                         result += ext->oe_nr_pages;
2895                         if (!discard) {
2896                                 struct list_head *list = NULL;
2897                                 if (hp) {
2898                                         EASSERT(!ext->oe_hp, ext);
2899                                         ext->oe_hp = 1;
2900                                         list = &obj->oo_hp_exts;
2901                                 } else if (!ext->oe_urgent && !ext->oe_hp) {
2902                                         ext->oe_urgent = 1;
2903                                         list = &obj->oo_urgent_exts;
2904                                 }
2905                                 if (list != NULL)
2906                                         list_move_tail(&ext->oe_link, list);
2907                                 unplug = true;
2908                         } else {
2909                                 struct client_obd *cli = osc_cli(obj);
2910                                 int pcc_bits = cli->cl_chunkbits - PAGE_SHIFT;
2911                                 pgoff_t align_by = (1 << pcc_bits);
2912                                 pgoff_t a_start = round_down(start, align_by);
2913                                 pgoff_t a_end = round_up(end, align_by);
2914
2915                                 /* overflow case */
2916                                 if (end && !a_end)
2917                                         a_end = CL_PAGE_EOF;
2918                                 /* the only discarder is lock cancelling, so
2919                                  * [start, end], aligned by chunk size, must
2920                                  * contain this extent */
2921                                 LASSERTF(ext->oe_start >= a_start &&
2922                                          ext->oe_end <= a_end,
2923                                          "ext [%lu, %lu] reg [%lu, %lu] "
2924                                          "orig [%lu %lu] align %lu bits "
2925                                          "%d\n", ext->oe_start, ext->oe_end,
2926                                          a_start, a_end, start, end,
2927                                          align_by, pcc_bits);
2928                                 osc_extent_state_set(ext, OES_LOCKING);
2929                                 ext->oe_owner = current;
2930                                 list_move_tail(&ext->oe_link,
2931                                                    &discard_list);
2932                                 osc_update_pending(obj, OBD_BRW_WRITE,
2933                                                    -ext->oe_nr_pages);
2934                         }
2935                         break;
2936                 case OES_ACTIVE:
2937                         /* It's pretty bad to wait for ACTIVE extents, because
2938                          * we don't know how long we will wait for it to be
2939                          * flushed since it may be blocked at awaiting more
2940                          * grants. We do this for the correctness of fsync. */
2941                         LASSERT(hp == 0 && discard == 0);
2942                         ext->oe_urgent = 1;
2943                         break;
2944                 case OES_TRUNC:
2945                         /* this extent is being truncated, can't do anything
2946                          * for it now. it will be set to urgent after truncate
2947                          * is finished in osc_cache_truncate_end(). */
2948                 default:
2949                         break;
2950                 }
2951                 ext = next_extent(ext);
2952         }
2953         osc_object_unlock(obj);
2954
2955         LASSERT(ergo(!discard, list_empty(&discard_list)));
2956         if (!list_empty(&discard_list)) {
2957                 struct osc_extent *tmp;
2958                 int rc;
2959
2960                 osc_list_maint(osc_cli(obj), obj);
2961                 list_for_each_entry_safe(ext, tmp, &discard_list, oe_link) {
2962                         list_del_init(&ext->oe_link);
2963                         EASSERT(ext->oe_state == OES_LOCKING, ext);
2964
2965                         /* Discard caching pages. We don't actually write this
2966                          * extent out but we complete it as if we did. */
2967                         rc = osc_extent_make_ready(env, ext);
2968                         if (unlikely(rc < 0)) {
2969                                 OSC_EXTENT_DUMP(D_ERROR, ext,
2970                                                 "make_ready returned %d\n", rc);
2971                                 if (result >= 0)
2972                                         result = rc;
2973                         }
2974
2975                         /* finish the extent as if the pages were sent */
2976                         osc_extent_finish(env, ext, 0, 0);
2977                 }
2978         }
2979
2980         if (unplug)
2981                 osc_io_unplug(env, osc_cli(obj), obj);
2982
2983         if (hp || discard) {
2984                 int rc;
2985                 rc = osc_cache_wait_range(env, obj, start, end);
2986                 if (result >= 0 && rc < 0)
2987                         result = rc;
2988         }
2989
2990         OSC_IO_DEBUG(obj, "pageout [%lu, %lu], %d.\n", start, end, result);
2991         RETURN(result);
2992 }
2993 EXPORT_SYMBOL(osc_cache_writeback_range);
2994
2995 /**
2996  * Returns a list of pages by a given [start, end] of \a obj.
2997  *
2998  * Gang tree lookup (radix_tree_gang_lookup()) optimization is absolutely
2999  * crucial in the face of [offset, EOF] locks.
3000  *
3001  * Return at least one page in @queue unless there is no covered page.
3002  */
3003 bool osc_page_gang_lookup(const struct lu_env *env, struct cl_io *io,
3004                           struct osc_object *osc, pgoff_t start, pgoff_t end,
3005                           osc_page_gang_cbt cb, void *cbdata)
3006 {
3007         struct osc_page *ops;
3008         struct pagevec  *pagevec;
3009         void            **pvec;
3010         pgoff_t         idx;
3011         unsigned int    nr;
3012         unsigned int    i;
3013         unsigned int    j;
3014         bool            res = true;
3015         bool            tree_lock = true;
3016         ENTRY;
3017
3018         idx = start;
3019         pvec = osc_env_info(env)->oti_pvec;
3020         pagevec = &osc_env_info(env)->oti_pagevec;
3021         ll_pagevec_init(pagevec, 0);
3022         spin_lock(&osc->oo_tree_lock);
3023         while ((nr = radix_tree_gang_lookup(&osc->oo_tree, pvec,
3024                                             idx, OTI_PVEC_SIZE)) > 0) {
3025                 struct cl_page *page;
3026                 bool end_of_region = false;
3027
3028                 for (i = 0, j = 0; i < nr; ++i) {
3029                         ops = pvec[i];
3030                         pvec[i] = NULL;
3031
3032                         idx = osc_index(ops);
3033                         if (idx > end) {
3034                                 end_of_region = true;
3035                                 break;
3036                         }
3037
3038                         page = ops->ops_cl.cpl_page;
3039                         LASSERT(page->cp_type == CPT_CACHEABLE);
3040                         if (page->cp_state == CPS_FREEING)
3041                                 continue;
3042
3043                         cl_page_get(page);
3044                         lu_ref_add_atomic(&page->cp_reference,
3045                                           "gang_lookup", current);
3046                         pvec[j++] = ops;
3047                 }
3048                 ++idx;
3049
3050                 /*
3051                  * Here a delicate locking dance is performed. Current thread
3052                  * holds a reference to a page, but has to own it before it
3053                  * can be placed into queue. Owning implies waiting, so
3054                  * radix-tree lock is to be released. After a wait one has to
3055                  * check that pages weren't truncated (cl_page_own() returns
3056                  * error in the latter case).
3057                  */
3058                 spin_unlock(&osc->oo_tree_lock);
3059                 tree_lock = false;
3060
3061                 for (i = 0; i < j; ++i) {
3062                         ops = pvec[i];
3063                         if (res)
3064                                 res = (*cb)(env, io, ops, cbdata);
3065
3066                         page = ops->ops_cl.cpl_page;
3067                         lu_ref_del(&page->cp_reference, "gang_lookup", current);
3068                         cl_pagevec_put(env, page, pagevec);
3069                 }
3070                 pagevec_release(pagevec);
3071
3072                 if (nr < OTI_PVEC_SIZE || end_of_region)
3073                         break;
3074
3075                 if (!res)
3076                         break;
3077                 if (need_resched())
3078                         cond_resched();
3079
3080                 spin_lock(&osc->oo_tree_lock);
3081                 tree_lock = true;
3082         }
3083         if (tree_lock)
3084                 spin_unlock(&osc->oo_tree_lock);
3085         RETURN(res);
3086 }
3087 EXPORT_SYMBOL(osc_page_gang_lookup);
3088
3089 /**
3090  * Check if page @page is covered by an extra lock or discard it.
3091  */
3092 static bool check_and_discard_cb(const struct lu_env *env, struct cl_io *io,
3093                                 struct osc_page *ops, void *cbdata)
3094 {
3095         struct osc_thread_info *info = osc_env_info(env);
3096         struct osc_object *osc = cbdata;
3097         pgoff_t index;
3098
3099         index = osc_index(ops);
3100         if (index >= info->oti_fn_index) {
3101                 struct ldlm_lock *tmp;
3102                 struct cl_page *page = ops->ops_cl.cpl_page;
3103
3104                 /* refresh non-overlapped index */
3105                 tmp = osc_dlmlock_at_pgoff(env, osc, index,
3106                                            OSC_DAP_FL_TEST_LOCK);
3107                 if (tmp != NULL) {
3108                         __u64 end = tmp->l_policy_data.l_extent.end;
3109                         /* Cache the first-non-overlapped index so as to skip
3110                          * all pages within [index, oti_fn_index). This is safe
3111                          * because if tmp lock is canceled, it will discard
3112                          * these pages. */
3113                         info->oti_fn_index = cl_index(osc2cl(osc), end + 1);
3114                         if (end == OBD_OBJECT_EOF)
3115                                 info->oti_fn_index = CL_PAGE_EOF;
3116                         LDLM_LOCK_PUT(tmp);
3117                 } else if (cl_page_own(env, io, page) == 0) {
3118                         /* discard the page */
3119                         cl_page_discard(env, io, page);
3120                         cl_page_disown(env, io, page);
3121                 } else {
3122                         LASSERT(page->cp_state == CPS_FREEING);
3123                 }
3124         }
3125
3126         info->oti_next_index = index + 1;
3127         return true;
3128 }
3129
3130 bool osc_discard_cb(const struct lu_env *env, struct cl_io *io,
3131                    struct osc_page *ops, void *cbdata)
3132 {
3133         struct osc_thread_info *info = osc_env_info(env);
3134         struct cl_page *page = ops->ops_cl.cpl_page;
3135
3136         /* page is top page. */
3137         info->oti_next_index = osc_index(ops) + 1;
3138         if (cl_page_own(env, io, page) == 0) {
3139                 if (!ergo(page->cp_type == CPT_CACHEABLE,
3140                           !PageDirty(cl_page_vmpage(page))))
3141                         CL_PAGE_DEBUG(D_ERROR, env, page,
3142                                         "discard dirty page?\n");
3143
3144                 /* discard the page */
3145                 cl_page_discard(env, io, page);
3146                 cl_page_disown(env, io, page);
3147         } else {
3148                 LASSERT(page->cp_state == CPS_FREEING);
3149         }
3150
3151         return true;
3152 }
3153 EXPORT_SYMBOL(osc_discard_cb);
3154
3155 /**
3156  * Discard pages protected by the given lock. This function traverses radix
3157  * tree to find all covering pages and discard them. If a page is being covered
3158  * by other locks, it should remain in cache.
3159  *
3160  * If error happens on any step, the process continues anyway (the reasoning
3161  * behind this being that lock cancellation cannot be delayed indefinitely).
3162  */
3163 int osc_lock_discard_pages(const struct lu_env *env, struct osc_object *osc,
3164                            pgoff_t start, pgoff_t end, bool discard)
3165 {
3166         struct osc_thread_info *info = osc_env_info(env);
3167         struct cl_io *io = osc_env_thread_io(env);
3168         osc_page_gang_cbt cb;
3169         int result;
3170
3171         ENTRY;
3172
3173         io->ci_obj = cl_object_top(osc2cl(osc));
3174         io->ci_ignore_layout = 1;
3175         result = cl_io_init(env, io, CIT_MISC, io->ci_obj);
3176         if (result != 0)
3177                 GOTO(out, result);
3178
3179         cb = discard ? osc_discard_cb : check_and_discard_cb;
3180         info->oti_fn_index = info->oti_next_index = start;
3181
3182         osc_page_gang_lookup(env, io, osc,
3183                              info->oti_next_index, end, cb, osc);
3184 out:
3185         cl_io_fini(env, io);
3186         RETURN(result);
3187 }
3188
3189
3190 /** @} osc */