lustre/obdecho/echo.c

   1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
   2  * vim:expandtab:shiftwidth=8:tabstop=8:
   3  *
   4  *  Copyright (c) 2001-2003 Cluster File Systems, Inc.
   5  *   Author: Peter Braam <braam@clusterfs.com>
   6  *   Author: Andreas Dilger <adilger@clusterfs.com>
   7  *
   8  *   This file is part of the Lustre file system, http://www.lustre.org
   9  *   Lustre is a trademark of Cluster File Systems, Inc.
  10  *
  11  *   You may have signed or agreed to another license before downloading
  12  *   this software.  If so, you are bound by the terms and conditions
  13  *   of that agreement, and the following does not apply to you.  See the
  14  *   LICENSE file included with this distribution for more information.
  15  *
  16  *   If you did not agree to a different license, then this copy of Lustre
  17  *   is open source software; you can redistribute it and/or modify it
  18  *   under the terms of version 2 of the GNU General Public License as
  19  *   published by the Free Software Foundation.
  20  *
  21  *   In either case, Lustre is distributed in the hope that it will be
  22  *   useful, but WITHOUT ANY WARRANTY; without even the implied warranty
  23  *   of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  24  *   license text for more details.
  25  */
  26
  27 #ifndef EXPORT_SYMTAB
  28 # define EXPORT_SYMTAB
  29 #endif
  30
  31 #include <linux/version.h>
  32 #include <linux/module.h>
  33 #include <linux/mm.h>
  34 #include <linux/highmem.h>
  35 #include <linux/fs.h>
  36 #include <linux/stat.h>
  37 #include <linux/sched.h>
  38 #include <linux/smp_lock.h>
  39 #include <linux/proc_fs.h>
  40 #include <linux/init.h>
  41 #include <asm/unistd.h>
  42
  43 #define DEBUG_SUBSYSTEM S_ECHO
  44
  45 #include <linux/obd_support.h>
  46 #include <linux/obd_class.h>
  47 #include <linux/obd_echo.h>
  48 #include <linux/lustre_debug.h>
  49 #include <linux/lustre_dlm.h>
  50 #include <linux/lprocfs_status.h>
  51
  52 #define ECHO_INIT_OBJID      0x1000000000000000ULL
  53 #define ECHO_HANDLE_MAGIC    0xabcd0123fedc9876ULL
  54
  55 #define ECHO_PERSISTENT_PAGES (ECHO_PERSISTENT_SIZE/PAGE_SIZE)
  56 static struct page *echo_persistent_pages[ECHO_PERSISTENT_PAGES];
  57
  58 enum {
  59         LPROC_ECHO_READ_BYTES = 1,
  60         LPROC_ECHO_WRITE_BYTES = 2,
  61         LPROC_ECHO_LAST = LPROC_ECHO_WRITE_BYTES +1
  62 };
  63
  64 static int echo_connect(struct lustre_handle *conn, struct obd_device *obd,
  65                         struct obd_uuid *cluuid, struct obd_connect_data *data)
  66 {
  67         data->ocd_connect_flags &= ECHO_CONNECT_SUPPORTED;
  68         return class_connect(conn, obd, cluuid);
  69 }
  70
  71 static int echo_disconnect(struct obd_export *exp)
  72 {
  73         unsigned long irqflags;
  74
  75         LASSERT (exp != NULL);
  76
  77         ldlm_cancel_locks_for_export(exp);
  78
  79         /* complete all outstanding replies */
  80         spin_lock_irqsave(&exp->exp_lock, irqflags);
  81         while (!list_empty(&exp->exp_outstanding_replies)) {
  82                 struct ptlrpc_reply_state *rs =
  83                         list_entry(exp->exp_outstanding_replies.next,
  84                                    struct ptlrpc_reply_state, rs_exp_list);
  85                 struct ptlrpc_service *svc = rs->rs_service;
  86
  87                 spin_lock(&svc->srv_lock);
  88                 list_del_init(&rs->rs_exp_list);
  89                 ptlrpc_schedule_difficult_reply(rs);
  90                 spin_unlock(&svc->srv_lock);
  91         }
  92         spin_unlock_irqrestore(&exp->exp_lock, irqflags);
  93
  94         return class_disconnect(exp);
  95 }
  96
  97 static int echo_destroy_export(struct obd_export *exp)
  98 {
  99         ENTRY;
 100
 101         target_destroy_export(exp);
 102
 103         RETURN(0);
 104 }
 105
 106  static __u64 echo_next_id(struct obd_device *obddev)
 107 {
 108         obd_id id;
 109
 110         spin_lock(&obddev->u.echo.eo_lock);
 111         id = ++obddev->u.echo.eo_lastino;
 112         spin_unlock(&obddev->u.echo.eo_lock);
 113
 114         return id;
 115 }
 116
 117 int echo_create(struct obd_export *exp, struct obdo *oa,
 118                 struct lov_stripe_md **ea, struct obd_trans_info *oti)
 119 {
 120         struct obd_device *obd = class_exp2obd(exp);
 121
 122         if (!obd) {
 123                 CERROR("invalid client cookie "LPX64"\n",
 124                        exp->exp_handle.h_cookie);
 125                 return -EINVAL;
 126         }
 127
 128         if (!(oa->o_mode && S_IFMT)) {
 129                 CERROR("echo obd: no type!\n");
 130                 return -ENOENT;
 131         }
 132
 133         if (!(oa->o_valid & OBD_MD_FLTYPE)) {
 134                 CERROR("invalid o_valid "LPX64"\n", oa->o_valid);
 135                 return -EINVAL;
 136         }
 137
 138         oa->o_id = echo_next_id(obd);
 139         oa->o_valid = OBD_MD_FLID;
 140
 141         return 0;
 142 }
 143
 144 int echo_destroy(struct obd_export *exp, struct obdo *oa,
 145                  struct lov_stripe_md *ea, struct obd_trans_info *oti,
 146                  struct obd_export *md_exp)
 147 {
 148         struct obd_device *obd = class_exp2obd(exp);
 149
 150         if (!obd) {
 151                 CERROR("invalid client cookie "LPX64"\n",
 152                        exp->exp_handle.h_cookie);
 153                 RETURN(-EINVAL);
 154         }
 155
 156         if (!(oa->o_valid & OBD_MD_FLID)) {
 157                 CERROR("obdo missing FLID valid flag: "LPX64"\n", oa->o_valid);
 158                 RETURN(-EINVAL);
 159         }
 160
 161         if (oa->o_id > obd->u.echo.eo_lastino || oa->o_id < ECHO_INIT_OBJID) {
 162                 CERROR("bad destroy objid: "LPX64"\n", oa->o_id);
 163                 RETURN(-EINVAL);
 164         }
 165
 166         return 0;
 167 }
 168
 169 static int echo_getattr(struct obd_export *exp, struct obdo *oa,
 170                         struct lov_stripe_md *md)
 171 {
 172         struct obd_device *obd = class_exp2obd(exp);
 173         obd_id id = oa->o_id;
 174
 175         if (!obd) {
 176                 CERROR("invalid client cookie "LPX64"\n",
 177                        exp->exp_handle.h_cookie);
 178                 RETURN(-EINVAL);
 179         }
 180
 181         if (!(oa->o_valid & OBD_MD_FLID)) {
 182                 CERROR("obdo missing FLID valid flag: "LPX64"\n", oa->o_valid);
 183                 RETURN(-EINVAL);
 184         }
 185
 186         obdo_cpy_md(oa, &obd->u.echo.eo_oa, oa->o_valid);
 187         oa->o_id = id;
 188
 189         return 0;
 190 }
 191
 192 static int echo_setattr(struct obd_export *exp, struct obdo *oa,
 193                         struct lov_stripe_md *md, struct obd_trans_info *oti)
 194 {
 195         struct obd_device *obd = class_exp2obd(exp);
 196
 197         if (!obd) {
 198                 CERROR("invalid client cookie "LPX64"\n",
 199                        exp->exp_handle.h_cookie);
 200                 RETURN(-EINVAL);
 201         }
 202
 203         if (!(oa->o_valid & OBD_MD_FLID)) {
 204                 CERROR("obdo missing FLID valid flag: "LPX64"\n", oa->o_valid);
 205                 RETURN(-EINVAL);
 206         }
 207
 208         memcpy(&obd->u.echo.eo_oa, oa, sizeof(*oa));
 209
 210         if (oa->o_id & 4) {
 211                 /* Save lock to force ACKed reply */
 212                 ldlm_lock_addref (&obd->u.echo.eo_nl_lock, LCK_NL);
 213                 oti->oti_ack_locks[0].mode = LCK_NL;
 214                 oti->oti_ack_locks[0].lock = obd->u.echo.eo_nl_lock;
 215         }
 216
 217         return 0;
 218 }
 219
 220 static void
 221 echo_page_debug_setup(struct page *page, int rw, obd_id id,
 222                       __u64 offset, int len)
 223 {
 224         int   page_offset = offset & (PAGE_SIZE - 1);
 225         char *addr        = ((char *)kmap(page)) + page_offset;
 226
 227         if (len % OBD_ECHO_BLOCK_SIZE != 0)
 228                 CERROR("Unexpected block size %d\n", len);
 229
 230         while (len > 0) {
 231                 if (rw & OBD_BRW_READ)
 232                         block_debug_setup(addr, OBD_ECHO_BLOCK_SIZE,
 233                                           offset, id);
 234                 else
 235                         block_debug_setup(addr, OBD_ECHO_BLOCK_SIZE,
 236                                           0xecc0ecc0ecc0ecc0ULL,
 237                                           0xecc0ecc0ecc0ecc0ULL);
 238
 239                 addr   += OBD_ECHO_BLOCK_SIZE;
 240                 offset += OBD_ECHO_BLOCK_SIZE;
 241                 len    -= OBD_ECHO_BLOCK_SIZE;
 242         }
 243
 244         kunmap(page);
 245 }
 246
 247 static int
 248 echo_page_debug_check(struct page *page, obd_id id,
 249                       __u64 offset, int len)
 250 {
 251         int   page_offset = offset & (PAGE_SIZE - 1);
 252         char *addr        = ((char *)kmap(page)) + page_offset;
 253         int   rc          = 0;
 254         int   rc2;
 255
 256         if (len % OBD_ECHO_BLOCK_SIZE != 0)
 257                 CERROR("Unexpected block size %d\n", len);
 258
 259         while (len > 0) {
 260                 rc2 = block_debug_check("echo", addr, OBD_ECHO_BLOCK_SIZE,
 261                                         offset, id);
 262
 263                 if (rc2 != 0 && rc == 0)
 264                         rc = rc2;
 265
 266                 addr   += OBD_ECHO_BLOCK_SIZE;
 267                 offset += OBD_ECHO_BLOCK_SIZE;
 268                 len    -= OBD_ECHO_BLOCK_SIZE;
 269         }
 270
 271         kunmap(page);
 272
 273         return (rc);
 274 }
 275
 276 /* This allows us to verify that desc_private is passed unmolested */
 277 #define DESC_PRIV 0x10293847
 278
 279 int echo_preprw(int cmd, struct obd_export *export, struct obdo *oa,
 280                 int objcount, struct obd_ioobj *obj, int niocount,
 281                 struct niobuf_remote *nb, struct niobuf_local *res,
 282                 struct obd_trans_info *oti)
 283 {
 284         struct obd_device *obd;
 285         struct niobuf_local *r = res;
 286         int tot_bytes = 0;
 287         int rc = 0;
 288         int i;
 289         ENTRY;
 290
 291         obd = export->exp_obd;
 292         if (obd == NULL)
 293                 RETURN(-EINVAL);
 294
 295         /* Temp fix to stop falling foul of osc_announce_cached() */
 296         oa->o_valid &= ~(OBD_MD_FLBLOCKS | OBD_MD_FLGRANT);
 297
 298         memset(res, 0, sizeof(*res) * niocount);
 299
 300         CDEBUG(D_PAGE, "%s %d obdos with %d IOs\n",
 301                cmd == OBD_BRW_READ ? "reading" : "writing", objcount, niocount);
 302
 303         if (oti)
 304                 oti->oti_handle = (void *)DESC_PRIV;
 305
 306         for (i = 0; i < objcount; i++, obj++) {
 307                 int gfp_mask = (obj->ioo_id & 1) ? GFP_HIGHUSER : GFP_KERNEL;
 308                 int ispersistent = obj->ioo_id == ECHO_PERSISTENT_OBJID;
 309                 int debug_setup = (!ispersistent &&
 310                                    (oa->o_valid & OBD_MD_FLFLAGS) != 0 &&
 311                                    (oa->o_flags & OBD_FL_DEBUG_CHECK) != 0);
 312                 int j;
 313
 314                 for (j = 0 ; j < obj->ioo_bufcnt ; j++, nb++, r++) {
 315
 316                         if (ispersistent &&
 317                             (nb->offset >> PAGE_SHIFT) < ECHO_PERSISTENT_PAGES) {
 318                                 r->page = echo_persistent_pages[nb->offset >>
 319                                                                 PAGE_SHIFT];
 320                                 /* Take extra ref so __free_pages() can be called OK */
 321                                 get_page (r->page);
 322                         } else {
 323                                 r->page = alloc_pages(gfp_mask, 0);
 324                                 if (r->page == NULL) {
 325                                         CERROR("can't get page %u/%u for id "
 326                                                LPU64"\n",
 327                                                j, obj->ioo_bufcnt, obj->ioo_id);
 328                                         GOTO(preprw_cleanup, rc = -ENOMEM);
 329                                 }
 330                         }
 331
 332                         tot_bytes += nb->len;
 333
 334                         atomic_inc(&obd->u.echo.eo_prep);
 335
 336                         r->offset = nb->offset;
 337                         r->len = nb->len;
 338                         LASSERT((r->offset & ~PAGE_MASK) + r->len <= PAGE_SIZE);
 339
 340                         CDEBUG(D_PAGE, "$$$$ get page %p @ "LPU64" for %d\n",
 341                                r->page, r->offset, r->len);
 342
 343                         if (cmd & OBD_BRW_READ)
 344                                 r->rc = r->len;
 345
 346                         if (debug_setup)
 347                                 echo_page_debug_setup(r->page, cmd, obj->ioo_id,
 348                                                       r->offset, r->len);
 349                 }
 350         }
 351         if (cmd & OBD_BRW_READ)
 352                 lprocfs_counter_add(obd->obd_stats, LPROC_ECHO_READ_BYTES,
 353                                     tot_bytes);
 354         else
 355                 lprocfs_counter_add(obd->obd_stats, LPROC_ECHO_WRITE_BYTES,
 356                                     tot_bytes);
 357
 358         CDEBUG(D_PAGE, "%d pages allocated after prep\n",
 359                atomic_read(&obd->u.echo.eo_prep));
 360
 361         RETURN(0);
 362
 363 preprw_cleanup:
 364         /* It is possible that we would rather handle errors by  allow
 365          * any already-set-up pages to complete, rather than tearing them
 366          * all down again.  I believe that this is what the in-kernel
 367          * prep/commit operations do.
 368          */
 369         CERROR("cleaning up %ld pages (%d obdos)\n", (long)(r - res), objcount);
 370         while (r-- > res) {
 371                 kunmap(r->page);
 372                 /* NB if this is a persistent page, __free_pages will just
 373                  * lose the extra ref gained above */
 374                 __free_pages(r->page, 0);
 375                 atomic_dec(&obd->u.echo.eo_prep);
 376         }
 377         memset(res, 0, sizeof(*res) * niocount);
 378
 379         return rc;
 380 }
 381
 382 int echo_commitrw(int cmd, struct obd_export *export, struct obdo *oa,
 383                   int objcount, struct obd_ioobj *obj, int niocount,
 384                   struct niobuf_local *res, struct obd_trans_info *oti, int rc)
 385 {
 386         struct obd_device *obd;
 387         struct niobuf_local *r = res;
 388         int i, vrc = 0;
 389         ENTRY;
 390
 391         obd = export->exp_obd;
 392         if (obd == NULL)
 393                 RETURN(-EINVAL);
 394
 395         if (rc)
 396                 GOTO(commitrw_cleanup, rc);
 397
 398         if ((cmd & OBD_BRW_RWMASK) == OBD_BRW_READ) {
 399                 CDEBUG(D_PAGE, "reading %d obdos with %d IOs\n",
 400                        objcount, niocount);
 401         } else {
 402                 CDEBUG(D_PAGE, "writing %d obdos with %d IOs\n",
 403                        objcount, niocount);
 404         }
 405
 406         if (niocount && !r) {
 407                 CERROR("NULL res niobuf with niocount %d\n", niocount);
 408                 RETURN(-EINVAL);
 409         }
 410
 411         LASSERT(oti == NULL || oti->oti_handle == (void *)DESC_PRIV);
 412
 413         for (i = 0; i < objcount; i++, obj++) {
 414                 int verify = (rc == 0 &&
 415                               obj->ioo_id != ECHO_PERSISTENT_OBJID &&
 416                               (oa->o_valid & OBD_MD_FLFLAGS) != 0 &&
 417                               (oa->o_flags & OBD_FL_DEBUG_CHECK) != 0);
 418                 int j;
 419
 420                 for (j = 0 ; j < obj->ioo_bufcnt ; j++, r++) {
 421                         struct page *page = r->page;
 422                         void *addr;
 423
 424                         if (page == NULL) {
 425                                 CERROR("null page objid "LPU64":%p, buf %d/%d\n",
 426                                        obj->ioo_id, page, j, obj->ioo_bufcnt);
 427                                 GOTO(commitrw_cleanup, rc = -EFAULT);
 428                         }
 429
 430                         addr = kmap(page);
 431
 432                         CDEBUG(D_PAGE, "$$$$ use page %p, addr %p@"LPU64"\n",
 433                                r->page, addr, r->offset);
 434
 435                         if (verify) {
 436                                 vrc = echo_page_debug_check(page, obj->ioo_id,
 437                                                             r->offset, r->len);
 438                                 /* check all the pages always */
 439                                 if (vrc != 0 && rc == 0)
 440                                         rc = vrc;
 441                         }
 442
 443                         kunmap(page);
 444                         /* NB see comment above regarding persistent pages */
 445                         __free_pages(page, 0);
 446                         atomic_dec(&obd->u.echo.eo_prep);
 447                 }
 448         }
 449         CDEBUG(D_PAGE, "%d pages remain after commit\n",
 450                atomic_read(&obd->u.echo.eo_prep));
 451         RETURN(rc);
 452
 453 commitrw_cleanup:
 454         CERROR("cleaning up %ld pages (%d obdos)\n",
 455                niocount - (long)(r - res) - 1, objcount);
 456         while (++r < res + niocount) {
 457                 struct page *page = r->page;
 458
 459                 /* NB see comment above regarding persistent pages */
 460                 __free_pages(page, 0);
 461                 atomic_dec(&obd->u.echo.eo_prep);
 462         }
 463         return rc;
 464 }
 465
 466 static int echo_setup(struct obd_device *obd, obd_count len, void *buf)
 467 {
 468         struct lprocfs_static_vars lvars;
 469         int                        rc;
 470         int                        lock_flags = 0;
 471         struct ldlm_res_id         res_id = {.name = {1}};
 472         ENTRY;
 473
 474         spin_lock_init(&obd->u.echo.eo_lock);
 475         obd->u.echo.eo_lastino = ECHO_INIT_OBJID;
 476
 477         obd->obd_namespace = ldlm_namespace_new("echo-tgt",
 478                                                 LDLM_NAMESPACE_SERVER);
 479         if (obd->obd_namespace == NULL) {
 480                 LBUG();
 481                 RETURN(-ENOMEM);
 482         }
 483
 484         rc = ldlm_cli_enqueue(NULL, NULL, obd->obd_namespace, res_id,
 485                               LDLM_PLAIN, NULL, LCK_NL, &lock_flags,
 486                               NULL, ldlm_completion_ast, NULL, NULL,
 487                               NULL, 0, NULL, &obd->u.echo.eo_nl_lock);
 488         LASSERT (rc == ELDLM_OK);
 489
 490         lprocfs_init_vars(echo, &lvars);
 491         if (lprocfs_obd_setup(obd, lvars.obd_vars) == 0 &&
 492             lprocfs_alloc_obd_stats(obd, LPROC_ECHO_LAST) == 0) {
 493                 lprocfs_counter_init(obd->obd_stats, LPROC_ECHO_READ_BYTES,
 494                                      LPROCFS_CNTR_AVGMINMAX,
 495                                      "read_bytes", "bytes");
 496                 lprocfs_counter_init(obd->obd_stats, LPROC_ECHO_WRITE_BYTES,
 497                                      LPROCFS_CNTR_AVGMINMAX,
 498                                      "write_bytes", "bytes");
 499         }
 500
 501         ptlrpc_init_client (LDLM_CB_REQUEST_PORTAL, LDLM_CB_REPLY_PORTAL,
 502                             "echo_ldlm_cb_client", &obd->obd_ldlm_client);
 503         RETURN(0);
 504 }
 505
 506 static int echo_cleanup(struct obd_device *obd)
 507 {
 508         int leaked;
 509         ENTRY;
 510
 511         lprocfs_free_obd_stats(obd);
 512         lprocfs_obd_cleanup(obd);
 513
 514         ldlm_lock_decref (&obd->u.echo.eo_nl_lock, LCK_NL);
 515
 516         /* XXX Bug 3413; wait for a bit to ensure the BL callback has
 517          * happened before calling ldlm_namespace_free() */
 518         set_current_state (TASK_UNINTERRUPTIBLE);
 519         schedule_timeout (HZ);
 520
 521         ldlm_namespace_free(obd->obd_namespace, obd->obd_force);
 522
 523         leaked = atomic_read(&obd->u.echo.eo_prep);
 524         if (leaked != 0)
 525                 CERROR("%d prep/commitrw pages leaked\n", leaked);
 526
 527         RETURN(0);
 528 }
 529
 530 static struct obd_ops echo_obd_ops = {
 531         .o_owner           = THIS_MODULE,
 532         .o_connect         = echo_connect,
 533         .o_disconnect      = echo_disconnect,
 534         .o_destroy_export  = echo_destroy_export,
 535         .o_create          = echo_create,
 536         .o_destroy         = echo_destroy,
 537         .o_getattr         = echo_getattr,
 538         .o_setattr         = echo_setattr,
 539         .o_preprw          = echo_preprw,
 540         .o_commitrw        = echo_commitrw,
 541         .o_setup           = echo_setup,
 542         .o_cleanup         = echo_cleanup
 543 };
 544
 545 extern int echo_client_init(void);
 546 extern void echo_client_exit(void);
 547
 548 static void
 549 echo_persistent_pages_fini (void)
 550 {
 551         int     i;
 552
 553         for (i = 0; i < ECHO_PERSISTENT_PAGES; i++)
 554                 if (echo_persistent_pages[i] != NULL) {
 555                         __free_pages (echo_persistent_pages[i], 0);
 556                         echo_persistent_pages[i] = NULL;
 557                 }
 558 }
 559
 560 static int
 561 echo_persistent_pages_init (void)
 562 {
 563         struct page *pg;
 564         int          i;
 565
 566         for (i = 0; i < ECHO_PERSISTENT_PAGES; i++) {
 567                 int gfp_mask = (i < ECHO_PERSISTENT_PAGES/2) ?
 568                         GFP_KERNEL : GFP_HIGHUSER;
 569
 570                 pg = alloc_pages (gfp_mask, 0);
 571                 if (pg == NULL) {
 572                         echo_persistent_pages_fini ();
 573                         return (-ENOMEM);
 574                 }
 575
 576                 memset (kmap (pg), 0, PAGE_SIZE);
 577                 kunmap (pg);
 578
 579                 echo_persistent_pages[i] = pg;
 580         }
 581
 582         return (0);
 583 }
 584
 585 static int __init obdecho_init(void)
 586 {
 587         struct lprocfs_static_vars lvars;
 588         int rc;
 589
 590         printk(KERN_INFO "Lustre: Echo OBD driver; info@clusterfs.com\n");
 591
 592         LASSERT(PAGE_SIZE % OBD_ECHO_BLOCK_SIZE == 0);
 593
 594         lprocfs_init_vars(echo, &lvars);
 595
 596         rc = echo_persistent_pages_init ();
 597         if (rc != 0)
 598                 goto failed_0;
 599
 600         rc = class_register_type(&echo_obd_ops, lvars.module_vars,
 601                                  OBD_ECHO_DEVICENAME);
 602         if (rc != 0)
 603                 goto failed_1;
 604
 605         rc = echo_client_init();
 606         if (rc == 0)
 607                 RETURN (0);
 608
 609         class_unregister_type(OBD_ECHO_DEVICENAME);
 610  failed_1:
 611         echo_persistent_pages_fini ();
 612  failed_0:
 613         RETURN(rc);
 614 }
 615
 616 static void /*__exit*/ obdecho_exit(void)
 617 {
 618         echo_client_exit();
 619         class_unregister_type(OBD_ECHO_DEVICENAME);
 620         echo_persistent_pages_fini ();
 621 }
 622
 623 MODULE_AUTHOR("Cluster File Systems, Inc. <info@clusterfs.com>");
 624 MODULE_DESCRIPTION("Lustre Testing Echo OBD driver");
 625 MODULE_LICENSE("GPL");
 626
 627 module_init(obdecho_init);
 628 module_exit(obdecho_exit);