lustre/obdecho/echo.c

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see
  18  * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
  19  *
  20  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  21  * CA 95054 USA or visit www.sun.com if you need additional information or
  22  * have any questions.
  23  *
  24  * GPL HEADER END
  25  */
  26 /*
  27  * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
  28  * Use is subject to license terms.
  29  *
  30  * Copyright (c) 2010, 2014, Intel Corporation.
  31  */
  32 /*
  33  * This file is part of Lustre, http://www.lustre.org/
  34  * Lustre is a trademark of Sun Microsystems, Inc.
  35  *
  36  * lustre/obdecho/echo.c
  37  *
  38  * Author: Peter Braam <braam@clusterfs.com>
  39  * Author: Andreas Dilger <adilger@clusterfs.com>
  40  */
  41
  42 #define DEBUG_SUBSYSTEM S_ECHO
  43
  44 #include <obd_support.h>
  45 #include <obd_class.h>
  46 #include <lustre_debug.h>
  47 #include <lustre_dlm.h>
  48 #include <lprocfs_status.h>
  49
  50 #include "echo_internal.h"
  51
  52 /* The echo objid needs to be below 2^32, because regular FID numbers are
  53  * limited to 2^32 objects in f_oid for the FID_SEQ_ECHO range. b=23335 */
  54 #define ECHO_INIT_OID        0x10000000ULL
  55 #define ECHO_HANDLE_MAGIC    0xabcd0123fedc9876ULL
  56
  57 #define ECHO_PERSISTENT_PAGES (ECHO_PERSISTENT_SIZE >> PAGE_CACHE_SHIFT)
  58 static struct page *echo_persistent_pages[ECHO_PERSISTENT_PAGES];
  59
  60 enum {
  61         LPROC_ECHO_READ_BYTES = 1,
  62         LPROC_ECHO_WRITE_BYTES = 2,
  63         LPROC_ECHO_LAST = LPROC_ECHO_WRITE_BYTES +1
  64 };
  65
  66 static int echo_connect(const struct lu_env *env,
  67                         struct obd_export **exp, struct obd_device *obd,
  68                         struct obd_uuid *cluuid, struct obd_connect_data *data,
  69                         void *localdata)
  70 {
  71         struct lustre_handle conn = { 0 };
  72         int rc;
  73
  74         data->ocd_connect_flags &= ECHO_CONNECT_SUPPORTED;
  75         rc = class_connect(&conn, obd, cluuid);
  76         if (rc) {
  77                 CERROR("can't connect %d\n", rc);
  78                 return rc;
  79         }
  80         *exp = class_conn2export(&conn);
  81
  82         return 0;
  83 }
  84
  85 static int echo_disconnect(struct obd_export *exp)
  86 {
  87         LASSERT (exp != NULL);
  88
  89         return server_disconnect_export(exp);
  90 }
  91
  92 static int echo_init_export(struct obd_export *exp)
  93 {
  94         return ldlm_init_export(exp);
  95 }
  96
  97 static int echo_destroy_export(struct obd_export *exp)
  98 {
  99         ENTRY;
 100
 101         target_destroy_export(exp);
 102         ldlm_destroy_export(exp);
 103
 104         RETURN(0);
 105 }
 106
 107 static u64 echo_next_id(struct obd_device *obddev)
 108 {
 109         u64 id;
 110
 111         spin_lock(&obddev->u.echo.eo_lock);
 112         id = ++obddev->u.echo.eo_lastino;
 113         spin_unlock(&obddev->u.echo.eo_lock);
 114
 115         return id;
 116 }
 117
 118 static int echo_create(const struct lu_env *env, struct obd_export *exp,
 119                        struct obdo *oa)
 120 {
 121         struct obd_device *obd = class_exp2obd(exp);
 122
 123         if (!obd) {
 124                 CERROR("invalid client cookie "LPX64"\n",
 125                        exp->exp_handle.h_cookie);
 126                 return -EINVAL;
 127         }
 128
 129         if (!(oa->o_mode & S_IFMT)) {
 130                 CERROR("echo obd: no type!\n");
 131                 return -ENOENT;
 132         }
 133
 134         if (!(oa->o_valid & OBD_MD_FLTYPE)) {
 135                 CERROR("invalid o_valid "LPX64"\n", oa->o_valid);
 136                 return -EINVAL;
 137         }
 138
 139         ostid_set_seq_echo(&oa->o_oi);
 140         ostid_set_id(&oa->o_oi, echo_next_id(obd));
 141         oa->o_valid = OBD_MD_FLID;
 142
 143         return 0;
 144 }
 145
 146 static int echo_destroy(const struct lu_env *env, struct obd_export *exp,
 147                         struct obdo *oa)
 148 {
 149         struct obd_device *obd = class_exp2obd(exp);
 150
 151         ENTRY;
 152         if (!obd) {
 153                 CERROR("invalid client cookie "LPX64"\n",
 154                        exp->exp_handle.h_cookie);
 155                 RETURN(-EINVAL);
 156         }
 157
 158         if (!(oa->o_valid & OBD_MD_FLID)) {
 159                 CERROR("obdo missing FLID valid flag: "LPX64"\n", oa->o_valid);
 160                 RETURN(-EINVAL);
 161         }
 162
 163         if (ostid_id(&oa->o_oi) > obd->u.echo.eo_lastino ||
 164             ostid_id(&oa->o_oi) < ECHO_INIT_OID) {
 165                 CERROR("bad destroy objid: "DOSTID"\n", POSTID(&oa->o_oi));
 166                 RETURN(-EINVAL);
 167         }
 168
 169         RETURN(0);
 170 }
 171
 172 static int echo_getattr(const struct lu_env *env, struct obd_export *exp,
 173                         struct obd_info *oinfo)
 174 {
 175         struct obd_device *obd = class_exp2obd(exp);
 176         u64 id = ostid_id(&oinfo->oi_oa->o_oi);
 177
 178         ENTRY;
 179         if (!obd) {
 180                 CERROR("invalid client cookie "LPX64"\n",
 181                        exp->exp_handle.h_cookie);
 182                 RETURN(-EINVAL);
 183         }
 184
 185         if (!(oinfo->oi_oa->o_valid & OBD_MD_FLID)) {
 186                 CERROR("obdo missing FLID valid flag: "LPX64"\n",
 187                        oinfo->oi_oa->o_valid);
 188                 RETURN(-EINVAL);
 189         }
 190
 191         obdo_cpy_md(oinfo->oi_oa, &obd->u.echo.eo_oa, oinfo->oi_oa->o_valid);
 192         ostid_set_seq_echo(&oinfo->oi_oa->o_oi);
 193         ostid_set_id(&oinfo->oi_oa->o_oi, id);
 194
 195         RETURN(0);
 196 }
 197
 198 static int echo_setattr(const struct lu_env *env, struct obd_export *exp,
 199                         struct obd_info *oinfo)
 200 {
 201         struct obd_device *obd = class_exp2obd(exp);
 202
 203         ENTRY;
 204         if (!obd) {
 205                 CERROR("invalid client cookie "LPX64"\n",
 206                        exp->exp_handle.h_cookie);
 207                 RETURN(-EINVAL);
 208         }
 209
 210         if (!(oinfo->oi_oa->o_valid & OBD_MD_FLID)) {
 211                 CERROR("obdo missing FLID valid flag: "LPX64"\n",
 212                        oinfo->oi_oa->o_valid);
 213                 RETURN(-EINVAL);
 214         }
 215
 216         memcpy(&obd->u.echo.eo_oa, oinfo->oi_oa, sizeof(*oinfo->oi_oa));
 217
 218         RETURN(0);
 219 }
 220
 221 static void
 222 echo_page_debug_setup(struct page *page, int rw, u64 id,
 223                       __u64 offset, int len)
 224 {
 225         int   page_offset = offset & ~PAGE_MASK;
 226         char *addr        = ((char *)kmap(page)) + page_offset;
 227
 228         if (len % OBD_ECHO_BLOCK_SIZE != 0)
 229                 CERROR("Unexpected block size %d\n", len);
 230
 231         while (len > 0) {
 232                 if (rw & OBD_BRW_READ)
 233                         block_debug_setup(addr, OBD_ECHO_BLOCK_SIZE,
 234                                           offset, id);
 235                 else
 236                         block_debug_setup(addr, OBD_ECHO_BLOCK_SIZE,
 237                                           0xecc0ecc0ecc0ecc0ULL,
 238                                           0xecc0ecc0ecc0ecc0ULL);
 239
 240                 addr   += OBD_ECHO_BLOCK_SIZE;
 241                 offset += OBD_ECHO_BLOCK_SIZE;
 242                 len    -= OBD_ECHO_BLOCK_SIZE;
 243         }
 244
 245         kunmap(page);
 246 }
 247
 248 static int
 249 echo_page_debug_check(struct page *page, u64 id,
 250                       __u64 offset, int len)
 251 {
 252         int   page_offset = offset & ~PAGE_MASK;
 253         char *addr        = ((char *)kmap(page)) + page_offset;
 254         int   rc          = 0;
 255         int   rc2;
 256
 257         if (len % OBD_ECHO_BLOCK_SIZE != 0)
 258                 CERROR("Unexpected block size %d\n", len);
 259
 260         while (len > 0) {
 261                 rc2 = block_debug_check("echo", addr, OBD_ECHO_BLOCK_SIZE,
 262                                         offset, id);
 263
 264                 if (rc2 != 0 && rc == 0)
 265                         rc = rc2;
 266
 267                 addr   += OBD_ECHO_BLOCK_SIZE;
 268                 offset += OBD_ECHO_BLOCK_SIZE;
 269                 len    -= OBD_ECHO_BLOCK_SIZE;
 270         }
 271
 272         kunmap(page);
 273
 274         return rc;
 275 }
 276
 277 static int echo_map_nb_to_lb(struct obdo *oa, struct obd_ioobj *obj,
 278                              struct niobuf_remote *nb, int *pages,
 279                              struct niobuf_local *lb, int cmd, int *left)
 280 {
 281         gfp_t gfp_mask = (ostid_id(&obj->ioo_oid) & 1) ?
 282                         GFP_HIGHUSER : GFP_IOFS;
 283         int ispersistent = ostid_id(&obj->ioo_oid) == ECHO_PERSISTENT_OBJID;
 284         int debug_setup = (!ispersistent &&
 285                            (oa->o_valid & OBD_MD_FLFLAGS) != 0 &&
 286                            (oa->o_flags & OBD_FL_DEBUG_CHECK) != 0);
 287         struct niobuf_local *res = lb;
 288         u64 offset = nb->rnb_offset;
 289         int len = nb->rnb_len;
 290
 291         while (len > 0) {
 292                 int plen = PAGE_CACHE_SIZE - (offset & (PAGE_CACHE_SIZE-1));
 293                 if (len < plen)
 294                         plen = len;
 295
 296                 /* check for local buf overflow */
 297                 if (*left == 0)
 298                         return -EINVAL;
 299
 300                 res->lnb_file_offset = offset;
 301                 res->lnb_len = plen;
 302                 LASSERT((res->lnb_file_offset & ~PAGE_MASK) +
 303                         res->lnb_len <= PAGE_CACHE_SIZE);
 304
 305                 if (ispersistent &&
 306                     ((res->lnb_file_offset >> PAGE_CACHE_SHIFT) <
 307                       ECHO_PERSISTENT_PAGES)) {
 308                         res->lnb_page =
 309                                 echo_persistent_pages[res->lnb_file_offset >>
 310                                                       PAGE_CACHE_SHIFT];
 311                         /* Take extra ref so __free_pages() can be called OK */
 312                         get_page(res->lnb_page);
 313                 } else {
 314                         OBD_PAGE_ALLOC(res->lnb_page, gfp_mask);
 315                         if (res->lnb_page == NULL) {
 316                                 CERROR("can't get page for id " DOSTID"\n",
 317                                        POSTID(&obj->ioo_oid));
 318                                 return -ENOMEM;
 319                         }
 320                 }
 321
 322                 CDEBUG(D_PAGE, "$$$$ get page %p @ "LPU64" for %d\n",
 323                        res->lnb_page, res->lnb_file_offset, res->lnb_len);
 324
 325                 if (cmd & OBD_BRW_READ)
 326                         res->lnb_rc = res->lnb_len;
 327
 328                 if (debug_setup)
 329                         echo_page_debug_setup(res->lnb_page, cmd,
 330                                               ostid_id(&obj->ioo_oid),
 331                                               res->lnb_file_offset,
 332                                               res->lnb_len);
 333
 334                 offset += plen;
 335                 len -= plen;
 336                 res++;
 337
 338                 (*left)--;
 339                 (*pages)++;
 340         }
 341
 342         return 0;
 343 }
 344
 345 static int echo_finalize_lb(struct obdo *oa, struct obd_ioobj *obj,
 346                             struct niobuf_remote *rb, int *pgs,
 347                             struct niobuf_local *lb, int verify)
 348 {
 349         struct niobuf_local *res = lb;
 350         u64 start = rb->rnb_offset >> PAGE_CACHE_SHIFT;
 351         u64 end   = (rb->rnb_offset + rb->rnb_len + PAGE_CACHE_SIZE - 1) >>
 352                     PAGE_CACHE_SHIFT;
 353         int     count  = (int)(end - start);
 354         int     rc     = 0;
 355         int     i;
 356
 357         for (i = 0; i < count; i++, (*pgs) ++, res++) {
 358                 struct page *page = res->lnb_page;
 359                 void       *addr;
 360
 361                 if (page == NULL) {
 362                         CERROR("null page objid "LPU64":%p, buf %d/%d\n",
 363                                ostid_id(&obj->ioo_oid), page, i,
 364                                obj->ioo_bufcnt);
 365                         return -EFAULT;
 366                 }
 367
 368                 addr = kmap(page);
 369
 370                 CDEBUG(D_PAGE, "$$$$ use page %p, addr %p@"LPU64"\n",
 371                        res->lnb_page, addr, res->lnb_file_offset);
 372
 373                 if (verify) {
 374                         int vrc = echo_page_debug_check(page,
 375                                                         ostid_id(&obj->ioo_oid),
 376                                                         res->lnb_file_offset,
 377                                                         res->lnb_len);
 378                         /* check all the pages always */
 379                         if (vrc != 0 && rc == 0)
 380                                 rc = vrc;
 381                 }
 382
 383                 kunmap(page);
 384                 /* NB see comment above regarding persistent pages */
 385                 OBD_PAGE_FREE(page);
 386         }
 387
 388         return rc;
 389 }
 390
 391 static int echo_preprw(const struct lu_env *env, int cmd,
 392                        struct obd_export *export, struct obdo *oa,
 393                        int objcount, struct obd_ioobj *obj,
 394                        struct niobuf_remote *nb, int *pages,
 395                        struct niobuf_local *res)
 396 {
 397         struct obd_device *obd;
 398         int tot_bytes = 0;
 399         int rc = 0;
 400         int i, left;
 401         ENTRY;
 402
 403         obd = export->exp_obd;
 404         if (obd == NULL)
 405                 RETURN(-EINVAL);
 406
 407         /* Temp fix to stop falling foul of osc_announce_cached() */
 408         oa->o_valid &= ~(OBD_MD_FLBLOCKS | OBD_MD_FLGRANT);
 409
 410         memset(res, 0, sizeof(*res) * *pages);
 411
 412         CDEBUG(D_PAGE, "%s %d obdos with %d IOs\n",
 413                cmd == OBD_BRW_READ ? "reading" : "writing", objcount, *pages);
 414
 415         left = *pages;
 416         *pages = 0;
 417
 418         for (i = 0; i < objcount; i++, obj++) {
 419                 int j;
 420
 421                 for (j = 0 ; j < obj->ioo_bufcnt ; j++, nb++) {
 422
 423                         rc = echo_map_nb_to_lb(oa, obj, nb, pages,
 424                                                res + *pages, cmd, &left);
 425                         if (rc)
 426                                 GOTO(preprw_cleanup, rc);
 427
 428                         tot_bytes += nb->rnb_len;
 429                 }
 430         }
 431
 432         atomic_add(*pages, &obd->u.echo.eo_prep);
 433
 434         if (cmd & OBD_BRW_READ)
 435                 lprocfs_counter_add(obd->obd_stats, LPROC_ECHO_READ_BYTES,
 436                                     tot_bytes);
 437         else
 438                 lprocfs_counter_add(obd->obd_stats, LPROC_ECHO_WRITE_BYTES,
 439                                     tot_bytes);
 440
 441         CDEBUG(D_PAGE, "%d pages allocated after prep\n",
 442                atomic_read(&obd->u.echo.eo_prep));
 443
 444         RETURN(0);
 445
 446 preprw_cleanup:
 447         /* It is possible that we would rather handle errors by  allow
 448          * any already-set-up pages to complete, rather than tearing them
 449          * all down again.  I believe that this is what the in-kernel
 450          * prep/commit operations do.
 451          */
 452         CERROR("cleaning up %u pages (%d obdos)\n", *pages, objcount);
 453         for (i = 0; i < *pages; i++) {
 454                 kunmap(res[i].lnb_page);
 455                 /* NB if this is a persistent page, __free_pages will just
 456                  * lose the extra ref gained above */
 457                 OBD_PAGE_FREE(res[i].lnb_page);
 458                 res[i].lnb_page = NULL;
 459                 atomic_dec(&obd->u.echo.eo_prep);
 460         }
 461
 462         return rc;
 463 }
 464
 465 static int echo_commitrw(const struct lu_env *env, int cmd,
 466                          struct obd_export *export, struct obdo *oa,
 467                          int objcount, struct obd_ioobj *obj,
 468                          struct niobuf_remote *rb, int niocount,
 469                          struct niobuf_local *res, int rc)
 470 {
 471         struct obd_device *obd;
 472         int pgs = 0;
 473         int i;
 474         ENTRY;
 475
 476         obd = export->exp_obd;
 477         if (obd == NULL)
 478                 RETURN(-EINVAL);
 479
 480         if (rc)
 481                 GOTO(commitrw_cleanup, rc);
 482
 483         if ((cmd & OBD_BRW_RWMASK) == OBD_BRW_READ) {
 484                 CDEBUG(D_PAGE, "reading %d obdos with %d IOs\n",
 485                        objcount, niocount);
 486         } else {
 487                 CDEBUG(D_PAGE, "writing %d obdos with %d IOs\n",
 488                        objcount, niocount);
 489         }
 490
 491         if (niocount && res == NULL) {
 492                 CERROR("NULL res niobuf with niocount %d\n", niocount);
 493                 RETURN(-EINVAL);
 494         }
 495
 496         for (i = 0; i < objcount; i++, obj++) {
 497                 int verify = (rc == 0 &&
 498                              ostid_id(&obj->ioo_oid) != ECHO_PERSISTENT_OBJID &&
 499                               (oa->o_valid & OBD_MD_FLFLAGS) != 0 &&
 500                               (oa->o_flags & OBD_FL_DEBUG_CHECK) != 0);
 501                 int j;
 502
 503                 for (j = 0 ; j < obj->ioo_bufcnt ; j++, rb++) {
 504                         int vrc = echo_finalize_lb(oa, obj, rb, &pgs, &res[pgs],
 505                                                    verify);
 506                         if (vrc == 0)
 507                                 continue;
 508
 509                         if (vrc == -EFAULT)
 510                                 GOTO(commitrw_cleanup, rc = vrc);
 511
 512                         if (rc == 0)
 513                                 rc = vrc;
 514                 }
 515
 516         }
 517
 518         atomic_sub(pgs, &obd->u.echo.eo_prep);
 519
 520         CDEBUG(D_PAGE, "%d pages remain after commit\n",
 521                atomic_read(&obd->u.echo.eo_prep));
 522         RETURN(rc);
 523
 524 commitrw_cleanup:
 525         atomic_sub(pgs, &obd->u.echo.eo_prep);
 526
 527         CERROR("cleaning up %d pages (%d obdos)\n",
 528                niocount - pgs - 1, objcount);
 529
 530         while (pgs < niocount) {
 531                 struct page *page = res[pgs++].lnb_page;
 532
 533                 if (page == NULL)
 534                         continue;
 535
 536                 /* NB see comment above regarding persistent pages */
 537                 OBD_PAGE_FREE(page);
 538                 atomic_dec(&obd->u.echo.eo_prep);
 539         }
 540         return rc;
 541 }
 542
 543 LPROC_SEQ_FOPS_RO_TYPE(echo, uuid);
 544 static struct lprocfs_vars lprocfs_echo_obd_vars[] = {
 545         { .name =       "uuid",
 546           .fops =       &echo_uuid_fops         },
 547         { NULL }
 548 };
 549
 550 static int echo_setup(struct obd_device *obd, struct lustre_cfg *lcfg)
 551 {
 552         int                     rc;
 553         __u64                   lock_flags = 0;
 554         struct ldlm_res_id      res_id = {.name = {1}};
 555         char                    ns_name[48];
 556         ENTRY;
 557
 558         obd->u.echo.eo_obt.obt_magic = OBT_MAGIC;
 559         spin_lock_init(&obd->u.echo.eo_lock);
 560         obd->u.echo.eo_lastino = ECHO_INIT_OID;
 561
 562         sprintf(ns_name, "echotgt-%s", obd->obd_uuid.uuid);
 563         obd->obd_namespace = ldlm_namespace_new(obd, ns_name,
 564                                                 LDLM_NAMESPACE_SERVER,
 565                                                 LDLM_NAMESPACE_MODEST,
 566                                                 LDLM_NS_TYPE_OST);
 567         if (obd->obd_namespace == NULL) {
 568                 LBUG();
 569                 RETURN(-ENOMEM);
 570         }
 571
 572         rc = ldlm_cli_enqueue_local(obd->obd_namespace, &res_id, LDLM_PLAIN,
 573                                     NULL, LCK_NL, &lock_flags, NULL,
 574                                     ldlm_completion_ast, NULL, NULL, 0,
 575                                     LVB_T_NONE, NULL, &obd->u.echo.eo_nl_lock);
 576         LASSERT (rc == ELDLM_OK);
 577
 578         obd->obd_vars = lprocfs_echo_obd_vars;
 579         if (lprocfs_obd_setup(obd) == 0 &&
 580             lprocfs_alloc_obd_stats(obd, LPROC_ECHO_LAST) == 0) {
 581                 lprocfs_counter_init(obd->obd_stats, LPROC_ECHO_READ_BYTES,
 582                                      LPROCFS_CNTR_AVGMINMAX,
 583                                      "read_bytes", "bytes");
 584                 lprocfs_counter_init(obd->obd_stats, LPROC_ECHO_WRITE_BYTES,
 585                                      LPROCFS_CNTR_AVGMINMAX,
 586                                      "write_bytes", "bytes");
 587         }
 588
 589         ptlrpc_init_client(LDLM_CB_REQUEST_PORTAL, LDLM_CB_REPLY_PORTAL,
 590                            "echo_ldlm_cb_client", &obd->obd_ldlm_client);
 591         RETURN(0);
 592 }
 593
 594 static int echo_cleanup(struct obd_device *obd)
 595 {
 596         int leaked;
 597         ENTRY;
 598
 599         lprocfs_obd_cleanup(obd);
 600         lprocfs_free_obd_stats(obd);
 601
 602         ldlm_lock_decref(&obd->u.echo.eo_nl_lock, LCK_NL);
 603
 604         /* XXX Bug 3413; wait for a bit to ensure the BL callback has
 605          * happened before calling ldlm_namespace_free() */
 606         set_current_state(TASK_UNINTERRUPTIBLE);
 607         schedule_timeout(cfs_time_seconds(1));
 608
 609         ldlm_namespace_free(obd->obd_namespace, NULL, obd->obd_force);
 610         obd->obd_namespace = NULL;
 611
 612         leaked = atomic_read(&obd->u.echo.eo_prep);
 613         if (leaked != 0)
 614                 CERROR("%d prep/commitrw pages leaked\n", leaked);
 615
 616         RETURN(0);
 617 }
 618
 619 struct obd_ops echo_obd_ops = {
 620         .o_owner           = THIS_MODULE,
 621         .o_connect         = echo_connect,
 622         .o_disconnect      = echo_disconnect,
 623         .o_init_export     = echo_init_export,
 624         .o_destroy_export  = echo_destroy_export,
 625         .o_create          = echo_create,
 626         .o_destroy         = echo_destroy,
 627         .o_getattr         = echo_getattr,
 628         .o_setattr         = echo_setattr,
 629         .o_preprw          = echo_preprw,
 630         .o_commitrw        = echo_commitrw,
 631         .o_setup           = echo_setup,
 632         .o_cleanup         = echo_cleanup
 633 };
 634
 635 void echo_persistent_pages_fini(void)
 636 {
 637         int     i;
 638
 639         for (i = 0; i < ECHO_PERSISTENT_PAGES; i++)
 640                 if (echo_persistent_pages[i] != NULL) {
 641                         OBD_PAGE_FREE(echo_persistent_pages[i]);
 642                         echo_persistent_pages[i] = NULL;
 643                 }
 644 }
 645
 646 int echo_persistent_pages_init(void)
 647 {
 648         struct page *pg;
 649         int          i;
 650
 651         for (i = 0; i < ECHO_PERSISTENT_PAGES; i++) {
 652                 gfp_t gfp_mask = (i < ECHO_PERSISTENT_PAGES/2) ?
 653                         GFP_IOFS : GFP_HIGHUSER;
 654
 655                 OBD_PAGE_ALLOC(pg, gfp_mask);
 656                 if (pg == NULL) {
 657                         echo_persistent_pages_fini();
 658                         return -ENOMEM;
 659                 }
 660
 661                 memset (kmap (pg), 0, PAGE_CACHE_SIZE);
 662                 kunmap (pg);
 663
 664                 echo_persistent_pages[i] = pg;
 665         }
 666
 667         return 0;
 668 }