lustre/osc/osc_page.c

   1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
   2  * vim:expandtab:shiftwidth=8:tabstop=8:
   3  *
   4  * GPL HEADER START
   5  *
   6  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 only,
  10  * as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * General Public License version 2 for more details (a copy is included
  16  * in the LICENSE file that accompanied this code).
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * version 2 along with this program; If not, see
  20  * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
  21  *
  22  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  23  * CA 95054 USA or visit www.sun.com if you need additional information or
  24  * have any questions.
  25  *
  26  * GPL HEADER END
  27  */
  28 /*
  29  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
  30  * Use is subject to license terms.
  31  */
  32 /*
  33  * This file is part of Lustre, http://www.lustre.org/
  34  * Lustre is a trademark of Sun Microsystems, Inc.
  35  *
  36  * Implementation of cl_page for OSC layer.
  37  *
  38  *   Author: Nikita Danilov <nikita.danilov@sun.com>
  39  */
  40
  41 #define DEBUG_SUBSYSTEM S_OSC
  42
  43 #include "osc_cl_internal.h"
  44
  45 /** \addtogroup osc
  46  *  @{
  47  */
  48
  49 /*
  50  * Comment out osc_page_protected because it may sleep inside the
  51  * the client_obd_list_lock.
  52  * client_obd_list_lock -> osc_ap_completion -> osc_completion ->
  53  *   -> osc_page_protected -> osc_page_is_dlocked -> osc_match_base
  54  *   -> ldlm_lock_match -> sptlrpc_import_check_ctx -> sleep.
  55  */
  56 #if 0
  57 static int osc_page_is_dlocked(const struct lu_env *env,
  58                                const struct osc_page *opg,
  59                                enum cl_lock_mode mode, int pending, int unref)
  60 {
  61         struct cl_page         *page;
  62         struct osc_object      *obj;
  63         struct osc_thread_info *info;
  64         struct ldlm_res_id     *resname;
  65         struct lustre_handle   *lockh;
  66         ldlm_policy_data_t     *policy;
  67         ldlm_mode_t             dlmmode;
  68         int                     flags;
  69
  70         cfs_might_sleep();
  71
  72         info = osc_env_info(env);
  73         resname = &info->oti_resname;
  74         policy = &info->oti_policy;
  75         lockh = &info->oti_handle;
  76         page = opg->ops_cl.cpl_page;
  77         obj = cl2osc(opg->ops_cl.cpl_obj);
  78
  79         flags = LDLM_FL_TEST_LOCK | LDLM_FL_BLOCK_GRANTED;
  80         if (pending)
  81                 flags |= LDLM_FL_CBPENDING;
  82
  83         dlmmode = osc_cl_lock2ldlm(mode) | LCK_PW;
  84         osc_lock_build_res(env, obj, resname);
  85         osc_index2policy(policy, page->cp_obj, page->cp_index, page->cp_index);
  86         return osc_match_base(osc_export(obj), resname, LDLM_EXTENT, policy,
  87                               dlmmode, &flags, NULL, lockh, unref);
  88 }
  89
  90 /**
  91  * Checks an invariant that a page in the cache is covered by a lock, as
  92  * needed.
  93  */
  94 static int osc_page_protected(const struct lu_env *env,
  95                               const struct osc_page *opg,
  96                               enum cl_lock_mode mode, int unref)
  97 {
  98         struct cl_object_header *hdr;
  99         struct cl_lock          *scan;
 100         struct cl_page          *page;
 101         struct cl_lock_descr    *descr;
 102         int result;
 103
 104         LINVRNT(!opg->ops_temp);
 105
 106         page = opg->ops_cl.cpl_page;
 107         if (page->cp_owner != NULL &&
 108             cl_io_top(page->cp_owner)->ci_lockreq == CILR_NEVER)
 109                 /*
 110                  * If IO is done without locks (liblustre, or lloop), lock is
 111                  * not required.
 112                  */
 113                 result = 1;
 114         else
 115                 /* otherwise check for a DLM lock */
 116         result = osc_page_is_dlocked(env, opg, mode, 1, unref);
 117         if (result == 0) {
 118                 /* maybe this page is a part of a lockless io? */
 119                 hdr = cl_object_header(opg->ops_cl.cpl_obj);
 120                 descr = &osc_env_info(env)->oti_descr;
 121                 descr->cld_mode = mode;
 122                 descr->cld_start = page->cp_index;
 123                 descr->cld_end   = page->cp_index;
 124                 cfs_spin_lock(&hdr->coh_lock_guard);
 125                 cfs_list_for_each_entry(scan, &hdr->coh_locks, cll_linkage) {
 126                         /*
 127                          * Lock-less sub-lock has to be either in HELD state
 128                          * (when io is actively going on), or in CACHED state,
 129                          * when top-lock is being unlocked:
 130                          * cl_io_unlock()->cl_unuse()->...->lov_lock_unuse().
 131                          */
 132                         if ((scan->cll_state == CLS_HELD ||
 133                              scan->cll_state == CLS_CACHED) &&
 134                             cl_lock_ext_match(&scan->cll_descr, descr)) {
 135                                 struct osc_lock *olck;
 136
 137                                 olck = osc_lock_at(scan);
 138                                 result = osc_lock_is_lockless(olck);
 139                                 break;
 140                         }
 141                 }
 142                 cfs_spin_unlock(&hdr->coh_lock_guard);
 143         }
 144         return result;
 145 }
 146 #else
 147 static int osc_page_protected(const struct lu_env *env,
 148                               const struct osc_page *opg,
 149                               enum cl_lock_mode mode, int unref)
 150 {
 151         return 1;
 152 }
 153 #endif
 154
 155 /*****************************************************************************
 156  *
 157  * Page operations.
 158  *
 159  */
 160 static void osc_page_fini(const struct lu_env *env,
 161                           struct cl_page_slice *slice)
 162 {
 163         struct osc_page *opg = cl2osc_page(slice);
 164         CDEBUG(D_TRACE, "%p\n", opg);
 165         OBD_SLAB_FREE_PTR(opg, osc_page_kmem);
 166 }
 167
 168 static void osc_page_transfer_get(struct osc_page *opg, const char *label)
 169 {
 170         struct cl_page *page = cl_page_top(opg->ops_cl.cpl_page);
 171
 172         LASSERT(!opg->ops_transfer_pinned);
 173         cl_page_get(page);
 174         lu_ref_add_atomic(&page->cp_reference, label, page);
 175         opg->ops_transfer_pinned = 1;
 176 }
 177
 178 static void osc_page_transfer_put(const struct lu_env *env,
 179                                   struct osc_page *opg)
 180 {
 181         struct cl_page *page = cl_page_top(opg->ops_cl.cpl_page);
 182
 183         if (opg->ops_transfer_pinned) {
 184                 lu_ref_del(&page->cp_reference, "transfer", page);
 185                 opg->ops_transfer_pinned = 0;
 186                 cl_page_put(env, page);
 187         }
 188 }
 189
 190 /**
 191  * This is called once for every page when it is submitted for a transfer
 192  * either opportunistic (osc_page_cache_add()), or immediate
 193  * (osc_page_submit()).
 194  */
 195 static void osc_page_transfer_add(const struct lu_env *env,
 196                                   struct osc_page *opg, enum cl_req_type crt)
 197 {
 198         struct osc_object *obj;
 199
 200         LINVRNT(cl_page_is_vmlocked(env, opg->ops_cl.cpl_page));
 201
 202         obj = cl2osc(opg->ops_cl.cpl_obj);
 203         cfs_spin_lock(&obj->oo_seatbelt);
 204         cfs_list_add(&opg->ops_inflight, &obj->oo_inflight[crt]);
 205         opg->ops_submitter = cfs_current();
 206         cfs_spin_unlock(&obj->oo_seatbelt);
 207 }
 208
 209 static int osc_page_cache_add(const struct lu_env *env,
 210                               const struct cl_page_slice *slice,
 211                               struct cl_io *unused)
 212 {
 213         struct osc_page   *opg = cl2osc_page(slice);
 214         struct osc_object *obj = cl2osc(opg->ops_cl.cpl_obj);
 215         int result;
 216         /* All cacheable IO is async-capable */
 217         int brw_flags = OBD_BRW_ASYNC;
 218         int noquota = 0;
 219
 220         LINVRNT(osc_page_protected(env, opg, CLM_WRITE, 0));
 221         ENTRY;
 222
 223         /* Set the OBD_BRW_SRVLOCK before the page is queued. */
 224         brw_flags |= opg->ops_srvlock ? OBD_BRW_SRVLOCK : 0;
 225         if (!client_is_remote(osc_export(obj)) &&
 226             cfs_capable(CFS_CAP_SYS_RESOURCE)) {
 227                 brw_flags |= OBD_BRW_NOQUOTA;
 228                 noquota = OBD_BRW_NOQUOTA;
 229         }
 230
 231         osc_page_transfer_get(opg, "transfer\0cache");
 232         result = osc_queue_async_io(env, osc_export(obj), NULL, obj->oo_oinfo,
 233                                     &opg->ops_oap, OBD_BRW_WRITE | noquota,
 234                                     0, 0, brw_flags, 0);
 235         if (result != 0)
 236                 osc_page_transfer_put(env, opg);
 237         else
 238                 osc_page_transfer_add(env, opg, CRT_WRITE);
 239         RETURN(result);
 240 }
 241
 242 void osc_index2policy(ldlm_policy_data_t *policy, const struct cl_object *obj,
 243                       pgoff_t start, pgoff_t end)
 244 {
 245         memset(policy, 0, sizeof *policy);
 246         policy->l_extent.start = cl_offset(obj, start);
 247         policy->l_extent.end   = cl_offset(obj, end + 1) - 1;
 248 }
 249
 250 static int osc_page_is_under_lock(const struct lu_env *env,
 251                                   const struct cl_page_slice *slice,
 252                                   struct cl_io *unused)
 253 {
 254         struct cl_lock *lock;
 255         int             result;
 256
 257         ENTRY;
 258         lock = cl_lock_at_page(env, slice->cpl_obj, slice->cpl_page,
 259                                NULL, 1, 0);
 260         if (lock != NULL) {
 261                 cl_lock_put(env, lock);
 262                 result = -EBUSY;
 263         } else
 264                 result = -ENODATA;
 265         RETURN(result);
 266 }
 267
 268 static int osc_page_fail(const struct lu_env *env,
 269                          const struct cl_page_slice *slice,
 270                          struct cl_io *unused)
 271 {
 272         /*
 273          * Cached read?
 274          */
 275         LBUG();
 276         return 0;
 277 }
 278
 279
 280 static const char *osc_list(cfs_list_t *head)
 281 {
 282         return cfs_list_empty(head) ? "-" : "+";
 283 }
 284
 285 static inline cfs_time_t osc_submit_duration(struct osc_page *opg)
 286 {
 287         if (opg->ops_submit_time == 0)
 288                 return 0;
 289
 290         return (cfs_time_current() - opg->ops_submit_time);
 291 }
 292
 293 static int osc_page_print(const struct lu_env *env,
 294                           const struct cl_page_slice *slice,
 295                           void *cookie, lu_printer_t printer)
 296 {
 297         struct osc_page       *opg = cl2osc_page(slice);
 298         struct osc_async_page *oap = &opg->ops_oap;
 299         struct osc_object     *obj = cl2osc(slice->cpl_obj);
 300         struct client_obd     *cli = &osc_export(obj)->exp_obd->u.cli;
 301         struct lov_oinfo      *loi = obj->oo_oinfo;
 302
 303         return (*printer)(env, cookie, LUSTRE_OSC_NAME"-page@%p: "
 304                           "1< %#x %d %u %s %s %s > "
 305                           "2< "LPU64" %u %#x %#x | %p %p %p %p %p > "
 306                           "3< %s %p %d %lu %d > "
 307                           "4< %d %d %d %lu %s | %s %s %s %s > "
 308                           "5< %s %s %s %s | %d %s %s | %d %s %s>\n",
 309                           opg,
 310                           /* 1 */
 311                           oap->oap_magic, oap->oap_cmd,
 312                           oap->oap_interrupted,
 313                           osc_list(&oap->oap_pending_item),
 314                           osc_list(&oap->oap_urgent_item),
 315                           osc_list(&oap->oap_rpc_item),
 316                           /* 2 */
 317                           oap->oap_obj_off, oap->oap_page_off,
 318                           oap->oap_async_flags, oap->oap_brw_flags,
 319                           oap->oap_request,
 320                           oap->oap_cli, oap->oap_loi, oap->oap_caller_ops,
 321                           oap->oap_caller_data,
 322                           /* 3 */
 323                           osc_list(&opg->ops_inflight),
 324                           opg->ops_submitter, opg->ops_transfer_pinned,
 325                           osc_submit_duration(opg), opg->ops_srvlock,
 326                           /* 4 */
 327                           cli->cl_r_in_flight, cli->cl_w_in_flight,
 328                           cli->cl_max_rpcs_in_flight,
 329                           cli->cl_avail_grant,
 330                           osc_list(&cli->cl_cache_waiters),
 331                           osc_list(&cli->cl_loi_ready_list),
 332                           osc_list(&cli->cl_loi_hp_ready_list),
 333                           osc_list(&cli->cl_loi_write_list),
 334                           osc_list(&cli->cl_loi_read_list),
 335                           /* 5 */
 336                           osc_list(&loi->loi_ready_item),
 337                           osc_list(&loi->loi_hp_ready_item),
 338                           osc_list(&loi->loi_write_item),
 339                           osc_list(&loi->loi_read_item),
 340                           loi->loi_read_lop.lop_num_pending,
 341                           osc_list(&loi->loi_read_lop.lop_pending),
 342                           osc_list(&loi->loi_read_lop.lop_urgent),
 343                           loi->loi_write_lop.lop_num_pending,
 344                           osc_list(&loi->loi_write_lop.lop_pending),
 345                           osc_list(&loi->loi_write_lop.lop_urgent));
 346 }
 347
 348 static void osc_page_delete(const struct lu_env *env,
 349                             const struct cl_page_slice *slice)
 350 {
 351         struct osc_page       *opg = cl2osc_page(slice);
 352         struct osc_object     *obj = cl2osc(opg->ops_cl.cpl_obj);
 353         struct osc_async_page *oap = &opg->ops_oap;
 354         int rc;
 355
 356         LINVRNT(opg->ops_temp || osc_page_protected(env, opg, CLM_READ, 1));
 357
 358         ENTRY;
 359         CDEBUG(D_TRACE, "%p\n", opg);
 360         osc_page_transfer_put(env, opg);
 361         rc = osc_teardown_async_page(osc_export(obj), NULL, obj->oo_oinfo, oap);
 362         if (rc) {
 363                 CL_PAGE_DEBUG(D_ERROR, env, cl_page_top(slice->cpl_page),
 364                               "Trying to teardown failed: %d\n", rc);
 365                 LASSERT(0);
 366         }
 367         cfs_spin_lock(&obj->oo_seatbelt);
 368         cfs_list_del_init(&opg->ops_inflight);
 369         cfs_spin_unlock(&obj->oo_seatbelt);
 370         EXIT;
 371 }
 372
 373 void osc_page_clip(const struct lu_env *env, const struct cl_page_slice *slice,
 374                    int from, int to)
 375 {
 376         struct osc_page       *opg = cl2osc_page(slice);
 377         struct osc_async_page *oap = &opg->ops_oap;
 378
 379         LINVRNT(osc_page_protected(env, opg, CLM_READ, 0));
 380
 381         opg->ops_from = from;
 382         opg->ops_to   = to;
 383         cfs_spin_lock(&oap->oap_lock);
 384         oap->oap_async_flags |= ASYNC_COUNT_STABLE;
 385         cfs_spin_unlock(&oap->oap_lock);
 386 }
 387
 388 static int osc_page_cancel(const struct lu_env *env,
 389                            const struct cl_page_slice *slice)
 390 {
 391         struct osc_page *opg       = cl2osc_page(slice);
 392         struct osc_async_page *oap = &opg->ops_oap;
 393         int rc = 0;
 394
 395         LINVRNT(osc_page_protected(env, opg, CLM_READ, 0));
 396
 397         client_obd_list_lock(&oap->oap_cli->cl_loi_list_lock);
 398         /* Check if the transferring against this page
 399          * is completed, or not even queued. */
 400         if (opg->ops_transfer_pinned)
 401                 /* FIXME: may not be interrupted.. */
 402                 rc = osc_oap_interrupted(env, oap);
 403         LASSERT(ergo(rc == 0, opg->ops_transfer_pinned == 0));
 404         client_obd_list_unlock(&oap->oap_cli->cl_loi_list_lock);
 405         return rc;
 406 }
 407
 408 static const struct cl_page_operations osc_page_ops = {
 409         .cpo_fini          = osc_page_fini,
 410         .cpo_print         = osc_page_print,
 411         .cpo_delete        = osc_page_delete,
 412         .cpo_is_under_lock = osc_page_is_under_lock,
 413         .io = {
 414                 [CRT_READ] = {
 415                         .cpo_cache_add = osc_page_fail
 416                 },
 417                 [CRT_WRITE] = {
 418                         .cpo_cache_add = osc_page_cache_add
 419                 }
 420         },
 421         .cpo_clip           = osc_page_clip,
 422         .cpo_cancel         = osc_page_cancel
 423 };
 424
 425 static int osc_make_ready(const struct lu_env *env, void *data, int cmd)
 426 {
 427         struct osc_page *opg  = data;
 428         struct cl_page  *page = cl_page_top(opg->ops_cl.cpl_page);
 429         int result;
 430
 431         LASSERT(cmd == OBD_BRW_WRITE); /* no cached reads */
 432         LINVRNT(osc_page_protected(env, opg, CLM_WRITE, 1));
 433
 434         ENTRY;
 435         result = cl_page_make_ready(env, page, CRT_WRITE);
 436         if (result == 0)
 437                 opg->ops_submit_time = cfs_time_current();
 438         RETURN(result);
 439 }
 440
 441 static int osc_refresh_count(const struct lu_env *env, void *data, int cmd)
 442 {
 443         struct cl_page   *page;
 444         struct osc_page  *osc = data;
 445         struct cl_object *obj;
 446         struct cl_attr   *attr = &osc_env_info(env)->oti_attr;
 447
 448         int result;
 449         loff_t kms;
 450
 451         LINVRNT(osc_page_protected(env, osc, CLM_READ, 1));
 452
 453         /* readpage queues with _COUNT_STABLE, shouldn't get here. */
 454         LASSERT(!(cmd & OBD_BRW_READ));
 455         LASSERT(osc != NULL);
 456         page = osc->ops_cl.cpl_page;
 457         obj = osc->ops_cl.cpl_obj;
 458
 459         cl_object_attr_lock(obj);
 460         result = cl_object_attr_get(env, obj, attr);
 461         cl_object_attr_unlock(obj);
 462         if (result < 0)
 463                 return result;
 464         kms = attr->cat_kms;
 465         if (cl_offset(obj, page->cp_index) >= kms)
 466                 /* catch race with truncate */
 467                 return 0;
 468         else if (cl_offset(obj, page->cp_index + 1) > kms)
 469                 /* catch sub-page write at end of file */
 470                 return kms % CFS_PAGE_SIZE;
 471         else
 472                 return CFS_PAGE_SIZE;
 473 }
 474
 475 static int osc_completion(const struct lu_env *env,
 476                           void *data, int cmd, struct obdo *oa, int rc)
 477 {
 478         struct osc_page       *opg  = data;
 479         struct osc_async_page *oap  = &opg->ops_oap;
 480         struct cl_page        *page = cl_page_top(opg->ops_cl.cpl_page);
 481         struct osc_object     *obj  = cl2osc(opg->ops_cl.cpl_obj);
 482         enum cl_req_type crt;
 483
 484         LINVRNT(osc_page_protected(env, opg, CLM_READ, 1));
 485         LINVRNT(cl_page_is_vmlocked(env, page));
 486
 487         ENTRY;
 488
 489         cmd &= ~OBD_BRW_NOQUOTA;
 490         LASSERT(equi(page->cp_state == CPS_PAGEIN,  cmd == OBD_BRW_READ));
 491         LASSERT(equi(page->cp_state == CPS_PAGEOUT, cmd == OBD_BRW_WRITE));
 492         LASSERT(opg->ops_transfer_pinned);
 493
 494         /*
 495          * page->cp_req can be NULL if io submission failed before
 496          * cl_req was allocated.
 497          */
 498         if (page->cp_req != NULL)
 499                 cl_req_page_done(env, page);
 500         LASSERT(page->cp_req == NULL);
 501
 502         /* As the transfer for this page is being done, clear the flags */
 503         cfs_spin_lock(&oap->oap_lock);
 504         oap->oap_async_flags = 0;
 505         cfs_spin_unlock(&oap->oap_lock);
 506
 507         crt = cmd == OBD_BRW_READ ? CRT_READ : CRT_WRITE;
 508         /* Clear opg->ops_transfer_pinned before VM lock is released. */
 509         opg->ops_transfer_pinned = 0;
 510
 511         cfs_spin_lock(&obj->oo_seatbelt);
 512         LASSERT(opg->ops_submitter != NULL);
 513         LASSERT(!cfs_list_empty(&opg->ops_inflight));
 514         cfs_list_del_init(&opg->ops_inflight);
 515         cfs_spin_unlock(&obj->oo_seatbelt);
 516
 517         opg->ops_submit_time = 0;
 518
 519         cl_page_completion(env, page, crt, rc);
 520
 521         /* statistic */
 522         if (rc == 0 && oap->oap_brw_flags & OBD_BRW_SRVLOCK) {
 523                 struct lu_device *ld    = opg->ops_cl.cpl_obj->co_lu.lo_dev;
 524                 struct osc_stats *stats = &lu2osc_dev(ld)->od_stats;
 525                 int bytes = opg->ops_to - opg->ops_from;
 526
 527                 if (crt == CRT_READ)
 528                         stats->os_lockless_reads += bytes;
 529                 else
 530                         stats->os_lockless_writes += bytes;
 531         }
 532
 533         /*
 534          * This has to be the last operation with the page, as locks are
 535          * released in cl_page_completion() and nothing except for the
 536          * reference counter protects page from concurrent reclaim.
 537          */
 538         lu_ref_del(&page->cp_reference, "transfer", page);
 539         /*
 540          * As page->cp_obj is pinned by a reference from page->cp_req, it is
 541          * safe to call cl_page_put() without risking object destruction in a
 542          * non-blocking context.
 543          */
 544         cl_page_put(env, page);
 545         RETURN(0);
 546 }
 547
 548 const static struct obd_async_page_ops osc_async_page_ops = {
 549         .ap_make_ready    = osc_make_ready,
 550         .ap_refresh_count = osc_refresh_count,
 551         .ap_completion    = osc_completion
 552 };
 553
 554 struct cl_page *osc_page_init(const struct lu_env *env,
 555                               struct cl_object *obj,
 556                               struct cl_page *page, cfs_page_t *vmpage)
 557 {
 558         struct osc_object *osc = cl2osc(obj);
 559         struct osc_page   *opg;
 560         int result;
 561
 562         OBD_SLAB_ALLOC_PTR_GFP(opg, osc_page_kmem, CFS_ALLOC_IO);
 563         if (opg != NULL) {
 564                 void *oap = &opg->ops_oap;
 565
 566                 opg->ops_from = 0;
 567                 opg->ops_to   = CFS_PAGE_SIZE;
 568
 569                 result = osc_prep_async_page(osc_export(osc),
 570                                              NULL, osc->oo_oinfo, vmpage,
 571                                              cl_offset(obj, page->cp_index),
 572                                              &osc_async_page_ops,
 573                                              opg, (void **)&oap, 1, NULL);
 574                 if (result == 0) {
 575                         struct osc_io *oio = osc_env_io(env);
 576                         opg->ops_srvlock = osc_io_srvlock(oio);
 577                         cl_page_slice_add(page, &opg->ops_cl, obj,
 578                                           &osc_page_ops);
 579                 }
 580                 /*
 581                  * Cannot assert osc_page_protected() here as read-ahead
 582                  * creates temporary pages outside of a lock.
 583                  */
 584 #ifdef INVARIANT_CHECK
 585                 opg->ops_temp = !osc_page_protected(env, opg, CLM_READ, 1);
 586 #endif
 587                 CFS_INIT_LIST_HEAD(&opg->ops_inflight);
 588         } else
 589                 result = -ENOMEM;
 590         return ERR_PTR(result);
 591 }
 592
 593 /**
 594  * Helper function called by osc_io_submit() for every page in an immediate
 595  * transfer (i.e., transferred synchronously).
 596  */
 597 void osc_io_submit_page(const struct lu_env *env,
 598                         struct osc_io *oio, struct osc_page *opg,
 599                         enum cl_req_type crt)
 600 {
 601         struct osc_async_page *oap = &opg->ops_oap;
 602         struct client_obd     *cli = oap->oap_cli;
 603         int flags = 0;
 604
 605         LINVRNT(osc_page_protected(env, opg,
 606                                    crt == CRT_WRITE ? CLM_WRITE : CLM_READ, 1));
 607
 608         oap->oap_page_off   = opg->ops_from;
 609         oap->oap_count      = opg->ops_to - opg->ops_from;
 610         /* Give a hint to OST that requests are coming from kswapd - bug19529 */
 611         if (cfs_memory_pressure_get())
 612                 oap->oap_brw_flags |= OBD_BRW_MEMALLOC;
 613         oap->oap_brw_flags |= OBD_BRW_SYNC;
 614         if (osc_io_srvlock(oio))
 615                 oap->oap_brw_flags |= OBD_BRW_SRVLOCK;
 616
 617         oap->oap_cmd = crt == CRT_WRITE ? OBD_BRW_WRITE : OBD_BRW_READ;
 618         if (!client_is_remote(osc_export(cl2osc(opg->ops_cl.cpl_obj))) &&
 619             cfs_capable(CFS_CAP_SYS_RESOURCE)) {
 620                 oap->oap_brw_flags |= OBD_BRW_NOQUOTA;
 621                 oap->oap_cmd |= OBD_BRW_NOQUOTA;
 622         }
 623
 624         if (oap->oap_cmd & OBD_BRW_READ)
 625                 flags = ASYNC_COUNT_STABLE;
 626         else if (!(oap->oap_brw_page.flag & OBD_BRW_FROM_GRANT))
 627                 osc_enter_cache_try(env, cli, oap->oap_loi, oap, 1);
 628
 629         cfs_spin_lock(&oap->oap_lock);
 630         oap->oap_async_flags |= OSC_FLAGS | flags;
 631         cfs_spin_unlock(&oap->oap_lock);
 632
 633         osc_oap_to_pending(oap);
 634         osc_page_transfer_get(opg, "transfer\0imm");
 635         osc_page_transfer_add(env, opg, crt);
 636 }
 637
 638 /** @} osc */