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