lustre/obdecho/echo.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) 2002, 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  * lustre/obdecho/echo.c
  37  *
  38  * Author: Peter Braam <braam@clusterfs.com>
  39  * Author: Andreas Dilger <adilger@clusterfs.com>
  40  */
  41
  42 #ifndef EXPORT_SYMTAB
  43 # define EXPORT_SYMTAB
  44 #endif
  45
  46 #define DEBUG_SUBSYSTEM S_ECHO
  47
  48 #include <obd_support.h>
  49 #include <obd_class.h>
  50 #include <obd_echo.h>
  51 #include <lustre_debug.h>
  52 #include <lustre_dlm.h>
  53 #include <lprocfs_status.h>
  54
  55 /* The echo objid needs to be below 2^32, because regular FID numbers are
  56  * limited to 2^32 objects in f_oid for the FID_SEQ_ECHO range. b=23335 */
  57 #define ECHO_INIT_OID        0x10000000ULL
  58 #define ECHO_HANDLE_MAGIC    0xabcd0123fedc9876ULL
  59
  60 #define ECHO_PERSISTENT_PAGES (ECHO_PERSISTENT_SIZE >> CFS_PAGE_SHIFT)
  61 static cfs_page_t *echo_persistent_pages[ECHO_PERSISTENT_PAGES];
  62
  63 enum {
  64         LPROC_ECHO_READ_BYTES = 1,
  65         LPROC_ECHO_WRITE_BYTES = 2,
  66         LPROC_ECHO_LAST = LPROC_ECHO_WRITE_BYTES +1
  67 };
  68
  69 static int echo_connect(struct lustre_handle *conn, struct obd_device *obd,
  70                         struct obd_uuid *cluuid, struct obd_connect_data *data,
  71                         void *localdata)
  72 {
  73         data->ocd_connect_flags &= ECHO_CONNECT_SUPPORTED;
  74         return class_connect(conn, obd, cluuid);
  75 }
  76
  77 static int echo_disconnect(struct obd_export *exp)
  78 {
  79         LASSERT (exp != NULL);
  80
  81         return server_disconnect_export(exp);
  82 }
  83
  84 static int echo_init_export(struct obd_export *exp)
  85 {
  86         return ldlm_init_export(exp);
  87 }
  88
  89 static int echo_destroy_export(struct obd_export *exp)
  90 {
  91         ENTRY;
  92
  93         target_destroy_export(exp);
  94         ldlm_destroy_export(exp);
  95
  96         RETURN(0);
  97 }
  98
  99  static __u64 echo_next_id(struct obd_device *obddev)
 100 {
 101         obd_id id;
 102
 103         spin_lock(&obddev->u.echo.eo_lock);
 104         id = ++obddev->u.echo.eo_lastino;
 105         spin_unlock(&obddev->u.echo.eo_lock);
 106
 107         return id;
 108 }
 109
 110 int echo_create(struct obd_export *exp, struct obdo *oa,
 111                 struct lov_stripe_md **ea, struct obd_trans_info *oti)
 112 {
 113         struct obd_device *obd = class_exp2obd(exp);
 114
 115         if (!obd) {
 116                 CERROR("invalid client cookie "LPX64"\n",
 117                        exp->exp_handle.h_cookie);
 118                 return -EINVAL;
 119         }
 120
 121         if (!(oa->o_mode && S_IFMT)) {
 122                 CERROR("echo obd: no type!\n");
 123                 return -ENOENT;
 124         }
 125
 126         if (!(oa->o_valid & OBD_MD_FLTYPE)) {
 127                 CERROR("invalid o_valid "LPX64"\n", oa->o_valid);
 128                 return -EINVAL;
 129         }
 130
 131         oa->o_id = echo_next_id(obd);
 132         oa->o_valid = OBD_MD_FLID;
 133
 134         return 0;
 135 }
 136
 137 int echo_destroy(struct obd_export *exp, struct obdo *oa,
 138                  struct lov_stripe_md *ea, struct obd_trans_info *oti,
 139                  struct obd_export *md_exp)
 140 {
 141         struct obd_device *obd = class_exp2obd(exp);
 142
 143         ENTRY;
 144         if (!obd) {
 145                 CERROR("invalid client cookie "LPX64"\n",
 146                        exp->exp_handle.h_cookie);
 147                 RETURN(-EINVAL);
 148         }
 149
 150         if (!(oa->o_valid & OBD_MD_FLID)) {
 151                 CERROR("obdo missing FLID valid flag: "LPX64"\n", oa->o_valid);
 152                 RETURN(-EINVAL);
 153         }
 154
 155         if (oa->o_id > obd->u.echo.eo_lastino || oa->o_id < ECHO_INIT_OID) {
 156                 CERROR("bad destroy objid: "LPX64"\n", oa->o_id);
 157                 RETURN(-EINVAL);
 158         }
 159
 160         RETURN(0);
 161 }
 162
 163 static int echo_getattr(struct obd_export *exp, struct obd_info *oinfo)
 164 {
 165         struct obd_device *obd = class_exp2obd(exp);
 166         obd_id id = oinfo->oi_oa->o_id;
 167
 168         ENTRY;
 169         if (!obd) {
 170                 CERROR("invalid client cookie "LPX64"\n",
 171                        exp->exp_handle.h_cookie);
 172                 RETURN(-EINVAL);
 173         }
 174
 175         if (!(oinfo->oi_oa->o_valid & OBD_MD_FLID)) {
 176                 CERROR("obdo missing FLID valid flag: "LPX64"\n",
 177                        oinfo->oi_oa->o_valid);
 178                 RETURN(-EINVAL);
 179         }
 180
 181         obdo_cpy_md(oinfo->oi_oa, &obd->u.echo.eo_oa, oinfo->oi_oa->o_valid);
 182         oinfo->oi_oa->o_id = id;
 183
 184         RETURN(0);
 185 }
 186
 187 static int echo_setattr(struct obd_export *exp, struct obd_info *oinfo,
 188                         struct obd_trans_info *oti)
 189 {
 190         struct obd_device *obd = class_exp2obd(exp);
 191
 192         ENTRY;
 193         if (!obd) {
 194                 CERROR("invalid client cookie "LPX64"\n",
 195                        exp->exp_handle.h_cookie);
 196                 RETURN(-EINVAL);
 197         }
 198
 199         if (!(oinfo->oi_oa->o_valid & OBD_MD_FLID)) {
 200                 CERROR("obdo missing FLID valid flag: "LPX64"\n",
 201                        oinfo->oi_oa->o_valid);
 202                 RETURN(-EINVAL);
 203         }
 204
 205         memcpy(&obd->u.echo.eo_oa, oinfo->oi_oa, sizeof(*oinfo->oi_oa));
 206
 207         if (oinfo->oi_oa->o_id & 4) {
 208                 /* Save lock to force ACKed reply */
 209                 ldlm_lock_addref (&obd->u.echo.eo_nl_lock, LCK_NL);
 210                 oti->oti_ack_locks[0].mode = LCK_NL;
 211                 oti->oti_ack_locks[0].lock = obd->u.echo.eo_nl_lock;
 212         }
 213
 214         RETURN(0);
 215 }
 216
 217 static void
 218 echo_page_debug_setup(cfs_page_t *page, int rw, obd_id id,
 219                       __u64 offset, int len)
 220 {
 221         int   page_offset = offset & ~CFS_PAGE_MASK;
 222         char *addr        = ((char *)cfs_kmap(page)) + page_offset;
 223
 224         if (len % OBD_ECHO_BLOCK_SIZE != 0)
 225                 CERROR("Unexpected block size %d\n", len);
 226
 227         while (len > 0) {
 228                 if (rw & OBD_BRW_READ)
 229                         block_debug_setup(addr, OBD_ECHO_BLOCK_SIZE,
 230                                           offset, id);
 231                 else
 232                         block_debug_setup(addr, OBD_ECHO_BLOCK_SIZE,
 233                                           0xecc0ecc0ecc0ecc0ULL,
 234                                           0xecc0ecc0ecc0ecc0ULL);
 235
 236                 addr   += OBD_ECHO_BLOCK_SIZE;
 237                 offset += OBD_ECHO_BLOCK_SIZE;
 238                 len    -= OBD_ECHO_BLOCK_SIZE;
 239         }
 240
 241         cfs_kunmap(page);
 242 }
 243
 244 static int
 245 echo_page_debug_check(cfs_page_t *page, obd_id id,
 246                       __u64 offset, int len)
 247 {
 248         int   page_offset = offset & ~CFS_PAGE_MASK;
 249         char *addr        = ((char *)cfs_kmap(page)) + page_offset;
 250         int   rc          = 0;
 251         int   rc2;
 252
 253         if (len % OBD_ECHO_BLOCK_SIZE != 0)
 254                 CERROR("Unexpected block size %d\n", len);
 255
 256         while (len > 0) {
 257                 rc2 = block_debug_check("echo", addr, OBD_ECHO_BLOCK_SIZE,
 258                                         offset, id);
 259
 260                 if (rc2 != 0 && rc == 0)
 261                         rc = rc2;
 262
 263                 addr   += OBD_ECHO_BLOCK_SIZE;
 264                 offset += OBD_ECHO_BLOCK_SIZE;
 265                 len    -= OBD_ECHO_BLOCK_SIZE;
 266         }
 267
 268         cfs_kunmap(page);
 269
 270         return (rc);
 271 }
 272
 273 /* This allows us to verify that desc_private is passed unmolested */
 274 #define DESC_PRIV 0x10293847
 275
 276 static int echo_map_nb_to_lb(struct obdo *oa, struct obd_ioobj *obj,
 277                              struct niobuf_remote *nb, int *pages,
 278                              struct niobuf_local *lb, int cmd, int *left)
 279 {
 280         int gfp_mask = (obj->ioo_id & 1) ? CFS_ALLOC_HIGHUSER : CFS_ALLOC_STD;
 281         int ispersistent = obj->ioo_id == ECHO_PERSISTENT_OBJID;
 282         int debug_setup = (!ispersistent &&
 283                            (oa->o_valid & OBD_MD_FLFLAGS) != 0 &&
 284                            (oa->o_flags & OBD_FL_DEBUG_CHECK) != 0);
 285         struct niobuf_local *res = lb;
 286         obd_off offset = nb->offset;
 287         int len = nb->len;
 288
 289         while (len > 0) {
 290                 int plen = CFS_PAGE_SIZE - (offset & (CFS_PAGE_SIZE-1));
 291                 if (len < plen)
 292                         plen = len;
 293
 294                 /* check for local buf overflow */
 295                 if (*left == 0)
 296                         return -EINVAL;
 297
 298                 res->offset = offset;
 299                 res->len = plen;
 300                 LASSERT((res->offset & ~CFS_PAGE_MASK) + res->len <= CFS_PAGE_SIZE);
 301
 302
 303                 if (ispersistent &&
 304                     (res->offset >> CFS_PAGE_SHIFT) < ECHO_PERSISTENT_PAGES) {
 305                         res->page = echo_persistent_pages[res->offset >>
 306                                 CFS_PAGE_SHIFT];
 307                         /* Take extra ref so __free_pages() can be called OK */
 308                         cfs_get_page (res->page);
 309                 } else {
 310                         OBD_PAGE_ALLOC(res->page, gfp_mask);
 311                         if (res->page == NULL) {
 312                                 CERROR("can't get page for id " LPU64"\n",
 313                                        obj->ioo_id);
 314                                 return -ENOMEM;
 315                         }
 316                 }
 317
 318                 CDEBUG(D_PAGE, "$$$$ get page %p @ "LPU64" for %d\n",
 319                        res->page, res->offset, res->len);
 320
 321                 if (cmd & OBD_BRW_READ)
 322                         res->rc = res->len;
 323
 324                 if (debug_setup)
 325                         echo_page_debug_setup(res->page, cmd, obj->ioo_id,
 326                                               res->offset, res->len);
 327
 328                 offset += plen;
 329                 len -= plen;
 330                 res++;
 331
 332                 (*left)--;
 333                 (*pages)++;
 334         }
 335
 336         return 0;
 337 }
 338
 339 int echo_preprw(int cmd, struct obd_export *export, struct obdo *oa,
 340                 int objcount, struct obd_ioobj *obj, struct niobuf_remote *nb,
 341                 int *pages, struct niobuf_local *res,
 342                 struct obd_trans_info *oti)
 343 {
 344         struct obd_device *obd;
 345         struct niobuf_local *r = res;
 346         int tot_bytes = 0;
 347         int rc = 0;
 348         int i, left;
 349         ENTRY;
 350
 351         obd = export->exp_obd;
 352         if (obd == NULL)
 353                 RETURN(-EINVAL);
 354
 355         /* Temp fix to stop falling foul of osc_announce_cached() */
 356         oa->o_valid &= ~(OBD_MD_FLBLOCKS | OBD_MD_FLGRANT);
 357
 358         memset(res, 0, sizeof(*res) * *pages);
 359
 360         CDEBUG(D_PAGE, "%s %d obdos with %d IOs\n",
 361                cmd == OBD_BRW_READ ? "reading" : "writing", objcount, *pages);
 362
 363         if (oti)
 364                 oti->oti_handle = (void *)DESC_PRIV;
 365
 366         left = *pages;
 367         *pages = 0;
 368
 369         for (i = 0; i < objcount; i++, obj++) {
 370                 int j;
 371
 372                 for (j = 0 ; j < obj->ioo_bufcnt ; j++, nb++, r++) {
 373
 374                         rc = echo_map_nb_to_lb(oa, obj, nb, pages,
 375                                                res + *pages, cmd, &left);
 376                         if (rc)
 377                                 GOTO(preprw_cleanup, rc);
 378
 379                         tot_bytes += nb->len;
 380                 }
 381         }
 382
 383         atomic_add(*pages, &obd->u.echo.eo_prep);
 384
 385         if (cmd & OBD_BRW_READ)
 386                 lprocfs_counter_add(obd->obd_stats, LPROC_ECHO_READ_BYTES,
 387                                     tot_bytes);
 388         else
 389                 lprocfs_counter_add(obd->obd_stats, LPROC_ECHO_WRITE_BYTES,
 390                                     tot_bytes);
 391
 392         CDEBUG(D_PAGE, "%d pages allocated after prep\n",
 393                atomic_read(&obd->u.echo.eo_prep));
 394
 395         RETURN(0);
 396
 397 preprw_cleanup:
 398         /* It is possible that we would rather handle errors by  allow
 399          * any already-set-up pages to complete, rather than tearing them
 400          * all down again.  I believe that this is what the in-kernel
 401          * prep/commit operations do.
 402          */
 403         CERROR("cleaning up %u pages (%d obdos)\n", *pages, objcount);
 404         for (i = 0; i < *pages; i++) {
 405                 cfs_kunmap(res[i].page);
 406                 /* NB if this is a persistent page, __free_pages will just
 407                  * lose the extra ref gained above */
 408                 OBD_PAGE_FREE(res[i].page);
 409                 res[i].page = NULL;
 410                 atomic_dec(&obd->u.echo.eo_prep);
 411         }
 412
 413         return rc;
 414 }
 415
 416 int echo_commitrw(int cmd, struct obd_export *export, struct obdo *oa,
 417                   int objcount, struct obd_ioobj *obj,
 418                   struct niobuf_remote *rb, int niocount,
 419                   struct niobuf_local *res, struct obd_trans_info *oti, int rc)
 420 {
 421         struct obd_device *obd;
 422         struct niobuf_local *r = res;
 423         struct niobuf_remote *rbc = rb;
 424         int i, vrc = 0;
 425         ENTRY;
 426
 427         obd = export->exp_obd;
 428         if (obd == NULL)
 429                 RETURN(-EINVAL);
 430
 431         if (rc)
 432                 GOTO(commitrw_cleanup, rc);
 433
 434         if ((cmd & OBD_BRW_RWMASK) == OBD_BRW_READ) {
 435                 CDEBUG(D_PAGE, "reading %d obdos with %d IOs\n",
 436                        objcount, niocount);
 437         } else {
 438                 CDEBUG(D_PAGE, "writing %d obdos with %d IOs\n",
 439                        objcount, niocount);
 440         }
 441
 442         if (niocount && !r) {
 443                 CERROR("NULL res niobuf with niocount %d\n", niocount);
 444                 RETURN(-EINVAL);
 445         }
 446
 447         LASSERT(oti == NULL || oti->oti_handle == (void *)DESC_PRIV);
 448
 449         for (i = 0; i < objcount; i++, obj++) {
 450                 int verify = (rc == 0 &&
 451                               obj->ioo_id != ECHO_PERSISTENT_OBJID &&
 452                               (oa->o_valid & OBD_MD_FLFLAGS) != 0 &&
 453                               (oa->o_flags & OBD_FL_DEBUG_CHECK) != 0);
 454                 int j;
 455
 456                 for (j = 0 ; j < obj->ioo_bufcnt ; j++, rbc++) {
 457                         long l;
 458                         for (l = rbc->len; l>0; l-=r->len, r++) {
 459                                 cfs_page_t *page = r->page;
 460                                 void *addr;
 461
 462                                 if (page == NULL) {
 463                                         CERROR("null page objid "LPU64":%p, buf %d/%d\n",
 464                                         obj->ioo_id, page, j, obj->ioo_bufcnt);
 465                                         GOTO(commitrw_cleanup, rc = -EFAULT);
 466                                 }
 467
 468                                 addr = cfs_kmap(page);
 469
 470                                 CDEBUG(D_PAGE, "$$$$ use page %p, addr %p@"LPU64"\n",
 471                                 r->page, addr, r->offset);
 472
 473                                 if (verify) {
 474                                         vrc = echo_page_debug_check(page, obj->ioo_id,
 475                                                                 r->offset, r->len);
 476                                         /* check all the pages always */
 477                                         if (vrc != 0 && rc == 0)
 478                                                 rc = vrc;
 479                                 }
 480
 481                                 cfs_kunmap(page);
 482                                 /* NB see comment above regarding persistent pages */
 483                                 OBD_PAGE_FREE(page);
 484                                 atomic_dec(&obd->u.echo.eo_prep);
 485                         }
 486                 }
 487         }
 488         CDEBUG(D_PAGE, "%d pages remain after commit\n",
 489                atomic_read(&obd->u.echo.eo_prep));
 490         RETURN(rc);
 491
 492 commitrw_cleanup:
 493         CERROR("cleaning up %ld pages (%d obdos)\n",
 494                niocount - (long)(r - res) - 1, objcount);
 495         while (++r < res + niocount) {
 496                 cfs_page_t *page = r->page;
 497
 498                 /* NB see comment above regarding persistent pages */
 499                 OBD_PAGE_FREE(page);
 500                 atomic_dec(&obd->u.echo.eo_prep);
 501         }
 502         return rc;
 503 }
 504
 505 static int echo_setup(struct obd_device *obd, obd_count len, void *buf)
 506 {
 507         struct lprocfs_static_vars lvars;
 508         int                        rc;
 509         int                        lock_flags = 0;
 510         struct ldlm_res_id         res_id = {.name = {1}};
 511         char                       ns_name[48];
 512         ENTRY;
 513
 514         spin_lock_init(&obd->u.echo.eo_lock);
 515         obd->u.echo.eo_lastino = ECHO_INIT_OID;
 516
 517         sprintf(ns_name, "echotgt-%s", obd->obd_uuid.uuid);
 518         obd->obd_namespace = ldlm_namespace_new(obd, ns_name,
 519                                                 LDLM_NAMESPACE_SERVER,
 520                                                 LDLM_NAMESPACE_GREEDY);
 521         if (obd->obd_namespace == NULL) {
 522                 LBUG();
 523                 RETURN(-ENOMEM);
 524         }
 525
 526         rc = ldlm_cli_enqueue_local(obd->obd_namespace, &res_id, LDLM_PLAIN,
 527                                     NULL, LCK_NL, &lock_flags, NULL,
 528                                     ldlm_completion_ast, NULL, NULL,
 529                                     0, NULL, &obd->u.echo.eo_nl_lock);
 530         LASSERT (rc == ELDLM_OK);
 531
 532         lprocfs_echo_init_vars(&lvars);
 533         if (lprocfs_obd_setup(obd, lvars.obd_vars) == 0 &&
 534             lprocfs_alloc_obd_stats(obd, LPROC_ECHO_LAST) == 0) {
 535                 lprocfs_counter_init(obd->obd_stats, LPROC_ECHO_READ_BYTES,
 536                                      LPROCFS_CNTR_AVGMINMAX,
 537                                      "read_bytes", "bytes");
 538                 lprocfs_counter_init(obd->obd_stats, LPROC_ECHO_WRITE_BYTES,
 539                                      LPROCFS_CNTR_AVGMINMAX,
 540                                      "write_bytes", "bytes");
 541         }
 542
 543         ptlrpc_init_client (LDLM_CB_REQUEST_PORTAL, LDLM_CB_REPLY_PORTAL,
 544                             "echo_ldlm_cb_client", &obd->obd_ldlm_client);
 545         RETURN(0);
 546 }
 547
 548 static int echo_cleanup(struct obd_device *obd)
 549 {
 550         int leaked;
 551         ENTRY;
 552
 553         lprocfs_obd_cleanup(obd);
 554         lprocfs_free_obd_stats(obd);
 555
 556         ldlm_lock_decref (&obd->u.echo.eo_nl_lock, LCK_NL);
 557
 558         /* XXX Bug 3413; wait for a bit to ensure the BL callback has
 559          * happened before calling ldlm_namespace_free() */
 560         cfs_schedule_timeout (CFS_TASK_UNINT, cfs_time_seconds(1));
 561
 562         ldlm_namespace_free(obd->obd_namespace, NULL, obd->obd_force);
 563         obd->obd_namespace = NULL;
 564
 565         leaked = atomic_read(&obd->u.echo.eo_prep);
 566         if (leaked != 0)
 567                 CERROR("%d prep/commitrw pages leaked\n", leaked);
 568
 569         RETURN(0);
 570 }
 571
 572 static struct obd_ops echo_obd_ops = {
 573         .o_owner           = THIS_MODULE,
 574         .o_connect         = echo_connect,
 575         .o_disconnect      = echo_disconnect,
 576         .o_init_export     = echo_init_export,
 577         .o_destroy_export  = echo_destroy_export,
 578         .o_create          = echo_create,
 579         .o_destroy         = echo_destroy,
 580         .o_getattr         = echo_getattr,
 581         .o_setattr         = echo_setattr,
 582         .o_preprw          = echo_preprw,
 583         .o_commitrw        = echo_commitrw,
 584         .o_setup           = echo_setup,
 585         .o_cleanup         = echo_cleanup
 586 };
 587
 588 extern int echo_client_init(void);
 589 extern void echo_client_exit(void);
 590
 591 static void
 592 echo_persistent_pages_fini (void)
 593 {
 594         int     i;
 595
 596         for (i = 0; i < ECHO_PERSISTENT_PAGES; i++)
 597                 if (echo_persistent_pages[i] != NULL) {
 598                         OBD_PAGE_FREE(echo_persistent_pages[i]);
 599                         echo_persistent_pages[i] = NULL;
 600                 }
 601 }
 602
 603 static int
 604 echo_persistent_pages_init (void)
 605 {
 606         cfs_page_t *pg;
 607         int          i;
 608
 609         for (i = 0; i < ECHO_PERSISTENT_PAGES; i++) {
 610                 int gfp_mask = (i < ECHO_PERSISTENT_PAGES/2) ?
 611                         CFS_ALLOC_STD : CFS_ALLOC_HIGHUSER;
 612
 613                 OBD_PAGE_ALLOC(pg, gfp_mask);
 614                 if (pg == NULL) {
 615                         echo_persistent_pages_fini ();
 616                         return (-ENOMEM);
 617                 }
 618
 619                 memset (cfs_kmap (pg), 0, CFS_PAGE_SIZE);
 620                 cfs_kunmap (pg);
 621
 622                 echo_persistent_pages[i] = pg;
 623         }
 624
 625         return (0);
 626 }
 627
 628 static int __init obdecho_init(void)
 629 {
 630         struct lprocfs_static_vars lvars;
 631         int rc;
 632
 633         ENTRY;
 634         printk(KERN_INFO "Lustre: Echo OBD driver; http://www.lustre.org/\n");
 635
 636         LASSERT(CFS_PAGE_SIZE % OBD_ECHO_BLOCK_SIZE == 0);
 637
 638         lprocfs_echo_init_vars(&lvars);
 639
 640         rc = echo_persistent_pages_init ();
 641         if (rc != 0)
 642                 goto failed_0;
 643
 644         rc = class_register_type(&echo_obd_ops, lvars.module_vars,
 645                                  LUSTRE_ECHO_NAME);
 646         if (rc != 0)
 647                 goto failed_1;
 648
 649         rc = echo_client_init();
 650         if (rc == 0)
 651                 RETURN (0);
 652
 653         class_unregister_type(LUSTRE_ECHO_NAME);
 654  failed_1:
 655         echo_persistent_pages_fini ();
 656  failed_0:
 657         RETURN(rc);
 658 }
 659
 660 static void /*__exit*/ obdecho_exit(void)
 661 {
 662         echo_client_exit();
 663         class_unregister_type(LUSTRE_ECHO_NAME);
 664         echo_persistent_pages_fini ();
 665 }
 666
 667 MODULE_AUTHOR("Sun Microsystems, Inc. <http://www.lustre.org/>");
 668 MODULE_DESCRIPTION("Lustre Testing Echo OBD driver");
 669 MODULE_LICENSE("GPL");
 670
 671 cfs_module(obdecho, "1.0.0", obdecho_init, obdecho_exit);