sys/geom/mountver/g_mountver.c

   1 /*-
   2  * Copyright (c) 2010 Edward Tomasz Napierala <trasz@FreeBSD.org>
   3  * Copyright (c) 2004-2006 Pawel Jakub Dawidek <pjd@FreeBSD.org>
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
  19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  */
  27
  28 #include <sys/cdefs.h>
  29 __FBSDID("$FreeBSD$");
  30
  31 #include <sys/param.h>
  32 #include <sys/systm.h>
  33 #include <sys/kernel.h>
  34 #include <sys/module.h>
  35 #include <sys/lock.h>
  36 #include <sys/mutex.h>
  37 #include <sys/bio.h>
  38 #include <sys/disk.h>
  39 #include <sys/proc.h>
  40 #include <sys/sbuf.h>
  41 #include <sys/sysctl.h>
  42 #include <sys/malloc.h>
  43 #include <sys/eventhandler.h>
  44 #include <geom/geom.h>
  45 #include <geom/mountver/g_mountver.h>
  46
  47
  48 SYSCTL_DECL(_kern_geom);
  49 static SYSCTL_NODE(_kern_geom, OID_AUTO, mountver, CTLFLAG_RW,
  50     0, "GEOM_MOUNTVER stuff");
  51 static u_int g_mountver_debug = 0;
  52 static u_int g_mountver_check_ident = 1;
  53 SYSCTL_UINT(_kern_geom_mountver, OID_AUTO, debug, CTLFLAG_RW,
  54     &g_mountver_debug, 0, "Debug level");
  55 SYSCTL_UINT(_kern_geom_mountver, OID_AUTO, check_ident, CTLFLAG_RW,
  56     &g_mountver_check_ident, 0, "Check disk ident when reattaching");
  57
  58 static eventhandler_tag g_mountver_pre_sync = NULL;
  59
  60 static void g_mountver_queue(struct bio *bp);
  61 static void g_mountver_orphan(struct g_consumer *cp);
  62 static void g_mountver_resize(struct g_consumer *cp);
  63 static int g_mountver_destroy(struct g_geom *gp, boolean_t force);
  64 static g_taste_t g_mountver_taste;
  65 static int g_mountver_destroy_geom(struct gctl_req *req, struct g_class *mp,
  66     struct g_geom *gp);
  67 static void g_mountver_config(struct gctl_req *req, struct g_class *mp,
  68     const char *verb);
  69 static void g_mountver_dumpconf(struct sbuf *sb, const char *indent,
  70     struct g_geom *gp, struct g_consumer *cp, struct g_provider *pp);
  71 static void g_mountver_init(struct g_class *mp);
  72 static void g_mountver_fini(struct g_class *mp);
  73
  74 struct g_class g_mountver_class = {
  75         .name = G_MOUNTVER_CLASS_NAME,
  76         .version = G_VERSION,
  77         .ctlreq = g_mountver_config,
  78         .taste = g_mountver_taste,
  79         .destroy_geom = g_mountver_destroy_geom,
  80         .init = g_mountver_init,
  81         .fini = g_mountver_fini
  82 };
  83
  84 static void
  85 g_mountver_done(struct bio *bp)
  86 {
  87         struct g_geom *gp;
  88         struct bio *pbp;
  89
  90         if (bp->bio_error != ENXIO) {
  91                 g_std_done(bp);
  92                 return;
  93         }
  94
  95         /*
  96          * When the device goes away, it's possible that few requests
  97          * will be completed with ENXIO before g_mountver_orphan()
  98          * gets called.  To work around that, we have to queue requests
  99          * that failed with ENXIO, in order to send them later.
 100          */
 101         gp = bp->bio_from->geom;
 102
 103         pbp = bp->bio_parent;
 104         KASSERT(pbp->bio_to == LIST_FIRST(&gp->provider),
 105             ("parent request was for someone else"));
 106         g_destroy_bio(bp);
 107         pbp->bio_inbed++;
 108         g_mountver_queue(pbp);
 109 }
 110
 111 static void
 112 g_mountver_send(struct bio *bp)
 113 {
 114         struct g_geom *gp;
 115         struct bio *cbp;
 116
 117         gp = bp->bio_to->geom;
 118
 119         cbp = g_clone_bio(bp);
 120         if (cbp == NULL) {
 121                 g_io_deliver(bp, ENOMEM);
 122                 return;
 123         }
 124
 125         cbp->bio_done = g_mountver_done;
 126         g_io_request(cbp, LIST_FIRST(&gp->consumer));
 127 }
 128
 129 static void
 130 g_mountver_queue(struct bio *bp)
 131 {
 132         struct g_mountver_softc *sc;
 133         struct g_geom *gp;
 134
 135         gp = bp->bio_to->geom;
 136         sc = gp->softc;
 137
 138         mtx_lock(&sc->sc_mtx);
 139         TAILQ_INSERT_TAIL(&sc->sc_queue, bp, bio_queue);
 140         mtx_unlock(&sc->sc_mtx);
 141 }
 142
 143 static void
 144 g_mountver_send_queued(struct g_geom *gp)
 145 {
 146         struct g_mountver_softc *sc;
 147         struct bio *bp;
 148
 149         sc = gp->softc;
 150
 151         mtx_lock(&sc->sc_mtx);
 152         while ((bp = TAILQ_FIRST(&sc->sc_queue)) != NULL) {
 153                 TAILQ_REMOVE(&sc->sc_queue, bp, bio_queue);
 154                 G_MOUNTVER_LOGREQ(bp, "Sending queued request.");
 155                 g_mountver_send(bp);
 156         }
 157         mtx_unlock(&sc->sc_mtx);
 158 }
 159
 160 static void
 161 g_mountver_discard_queued(struct g_geom *gp)
 162 {
 163         struct g_mountver_softc *sc;
 164         struct bio *bp;
 165
 166         sc = gp->softc;
 167
 168         mtx_lock(&sc->sc_mtx);
 169         while ((bp = TAILQ_FIRST(&sc->sc_queue)) != NULL) {
 170                 TAILQ_REMOVE(&sc->sc_queue, bp, bio_queue);
 171                 G_MOUNTVER_LOGREQ(bp, "Discarding queued request.");
 172                 g_io_deliver(bp, ENXIO);
 173         }
 174         mtx_unlock(&sc->sc_mtx);
 175 }
 176
 177 static void
 178 g_mountver_start(struct bio *bp)
 179 {
 180         struct g_mountver_softc *sc;
 181         struct g_geom *gp;
 182
 183         gp = bp->bio_to->geom;
 184         sc = gp->softc;
 185         G_MOUNTVER_LOGREQ(bp, "Request received.");
 186
 187         /*
 188          * It is possible that some bios were returned with ENXIO, even though
 189          * orphaning didn't happen yet.  In that case, queue all subsequent
 190          * requests in order to maintain ordering.
 191          */
 192         if (sc->sc_orphaned || !TAILQ_EMPTY(&sc->sc_queue)) {
 193                 G_MOUNTVER_LOGREQ(bp, "Queueing request.");
 194                 g_mountver_queue(bp);
 195                 if (!sc->sc_orphaned)
 196                         g_mountver_send_queued(gp);
 197         } else {
 198                 G_MOUNTVER_LOGREQ(bp, "Sending request.");
 199                 g_mountver_send(bp);
 200         }
 201 }
 202
 203 static int
 204 g_mountver_access(struct g_provider *pp, int dr, int dw, int de)
 205 {
 206         struct g_mountver_softc *sc;
 207         struct g_geom *gp;
 208         struct g_consumer *cp;
 209
 210         g_topology_assert();
 211
 212         gp = pp->geom;
 213         cp = LIST_FIRST(&gp->consumer);
 214         sc = gp->softc;
 215         if (sc == NULL && dr <= 0 && dw <= 0 && de <= 0)
 216                 return (0);
 217         KASSERT(sc != NULL, ("Trying to access withered provider \"%s\".", pp->name));
 218
 219         sc->sc_access_r += dr;
 220         sc->sc_access_w += dw;
 221         sc->sc_access_e += de;
 222
 223         if (sc->sc_orphaned)
 224                 return (0);
 225
 226         return (g_access(cp, dr, dw, de));
 227 }
 228
 229 static int
 230 g_mountver_create(struct gctl_req *req, struct g_class *mp, struct g_provider *pp)
 231 {
 232         struct g_mountver_softc *sc;
 233         struct g_geom *gp;
 234         struct g_provider *newpp;
 235         struct g_consumer *cp;
 236         char name[64];
 237         int error;
 238         int identsize = DISK_IDENT_SIZE;
 239
 240         g_topology_assert();
 241
 242         gp = NULL;
 243         newpp = NULL;
 244         cp = NULL;
 245
 246         snprintf(name, sizeof(name), "%s%s", pp->name, G_MOUNTVER_SUFFIX);
 247         LIST_FOREACH(gp, &mp->geom, geom) {
 248                 if (strcmp(gp->name, name) == 0) {
 249                         gctl_error(req, "Provider %s already exists.", name);
 250                         return (EEXIST);
 251                 }
 252         }
 253         gp = g_new_geomf(mp, "%s", name);
 254         sc = g_malloc(sizeof(*sc), M_WAITOK | M_ZERO);
 255         mtx_init(&sc->sc_mtx, "gmountver", NULL, MTX_DEF);
 256         TAILQ_INIT(&sc->sc_queue);
 257         sc->sc_provider_name = strdup(pp->name, M_GEOM);
 258         gp->softc = sc;
 259         gp->start = g_mountver_start;
 260         gp->orphan = g_mountver_orphan;
 261         gp->resize = g_mountver_resize;
 262         gp->access = g_mountver_access;
 263         gp->dumpconf = g_mountver_dumpconf;
 264
 265         newpp = g_new_providerf(gp, "%s", gp->name);
 266         newpp->mediasize = pp->mediasize;
 267         newpp->sectorsize = pp->sectorsize;
 268
 269         cp = g_new_consumer(gp);
 270         error = g_attach(cp, pp);
 271         if (error != 0) {
 272                 gctl_error(req, "Cannot attach to provider %s.", pp->name);
 273                 goto fail;
 274         }
 275         error = g_access(cp, 1, 0, 0);
 276         if (error != 0) {
 277                 gctl_error(req, "Cannot access provider %s.", pp->name);
 278                 goto fail;
 279         }
 280         error = g_io_getattr("GEOM::ident", cp, &identsize, sc->sc_ident);
 281         g_access(cp, -1, 0, 0);
 282         if (error != 0) {
 283                 if (g_mountver_check_ident) {
 284                         gctl_error(req, "Cannot get disk ident from %s; error = %d.", pp->name, error);
 285                         goto fail;
 286                 }
 287
 288                 G_MOUNTVER_DEBUG(0, "Cannot get disk ident from %s; error = %d.", pp->name, error);
 289                 sc->sc_ident[0] = '\0';
 290         }
 291
 292         g_error_provider(newpp, 0);
 293         G_MOUNTVER_DEBUG(0, "Device %s created.", gp->name);
 294         return (0);
 295 fail:
 296         g_free(sc->sc_provider_name);
 297         if (cp->provider != NULL)
 298                 g_detach(cp);
 299         g_destroy_consumer(cp);
 300         g_destroy_provider(newpp);
 301         g_free(gp->softc);
 302         g_destroy_geom(gp);
 303         return (error);
 304 }
 305
 306 static int
 307 g_mountver_destroy(struct g_geom *gp, boolean_t force)
 308 {
 309         struct g_mountver_softc *sc;
 310         struct g_provider *pp;
 311
 312         g_topology_assert();
 313         if (gp->softc == NULL)
 314                 return (ENXIO);
 315         sc = gp->softc;
 316         pp = LIST_FIRST(&gp->provider);
 317         if (pp != NULL && (pp->acr != 0 || pp->acw != 0 || pp->ace != 0)) {
 318                 if (force) {
 319                         G_MOUNTVER_DEBUG(0, "Device %s is still open, so it "
 320                             "can't be definitely removed.", pp->name);
 321                 } else {
 322                         G_MOUNTVER_DEBUG(1, "Device %s is still open (r%dw%de%d).",
 323                             pp->name, pp->acr, pp->acw, pp->ace);
 324                         return (EBUSY);
 325                 }
 326         } else {
 327                 G_MOUNTVER_DEBUG(0, "Device %s removed.", gp->name);
 328         }
 329         if (pp != NULL)
 330                 g_orphan_provider(pp, ENXIO);
 331         g_mountver_discard_queued(gp);
 332         g_free(sc->sc_provider_name);
 333         g_free(gp->softc);
 334         gp->softc = NULL;
 335         g_wither_geom(gp, ENXIO);
 336
 337         return (0);
 338 }
 339
 340 static int
 341 g_mountver_destroy_geom(struct gctl_req *req, struct g_class *mp, struct g_geom *gp)
 342 {
 343
 344         return (g_mountver_destroy(gp, 0));
 345 }
 346
 347 static void
 348 g_mountver_ctl_create(struct gctl_req *req, struct g_class *mp)
 349 {
 350         struct g_provider *pp;
 351         const char *name;
 352         char param[16];
 353         int i, *nargs;
 354
 355         g_topology_assert();
 356
 357         nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
 358         if (nargs == NULL) {
 359                 gctl_error(req, "No '%s' argument", "nargs");
 360                 return;
 361         }
 362         if (*nargs <= 0) {
 363                 gctl_error(req, "Missing device(s).");
 364                 return;
 365         }
 366         for (i = 0; i < *nargs; i++) {
 367                 snprintf(param, sizeof(param), "arg%d", i);
 368                 name = gctl_get_asciiparam(req, param);
 369                 if (name == NULL) {
 370                         gctl_error(req, "No 'arg%d' argument", i);
 371                         return;
 372                 }
 373                 if (strncmp(name, "/dev/", strlen("/dev/")) == 0)
 374                         name += strlen("/dev/");
 375                 pp = g_provider_by_name(name);
 376                 if (pp == NULL) {
 377                         G_MOUNTVER_DEBUG(1, "Provider %s is invalid.", name);
 378                         gctl_error(req, "Provider %s is invalid.", name);
 379                         return;
 380                 }
 381                 if (g_mountver_create(req, mp, pp) != 0)
 382                         return;
 383         }
 384 }
 385
 386 static struct g_geom *
 387 g_mountver_find_geom(struct g_class *mp, const char *name)
 388 {
 389         struct g_geom *gp;
 390
 391         LIST_FOREACH(gp, &mp->geom, geom) {
 392                 if (strcmp(gp->name, name) == 0)
 393                         return (gp);
 394         }
 395         return (NULL);
 396 }
 397
 398 static void
 399 g_mountver_ctl_destroy(struct gctl_req *req, struct g_class *mp)
 400 {
 401         int *nargs, *force, error, i;
 402         struct g_geom *gp;
 403         const char *name;
 404         char param[16];
 405
 406         g_topology_assert();
 407
 408         nargs = gctl_get_paraml(req, "nargs", sizeof(*nargs));
 409         if (nargs == NULL) {
 410                 gctl_error(req, "No '%s' argument", "nargs");
 411                 return;
 412         }
 413         if (*nargs <= 0) {
 414                 gctl_error(req, "Missing device(s).");
 415                 return;
 416         }
 417         force = gctl_get_paraml(req, "force", sizeof(*force));
 418         if (force == NULL) {
 419                 gctl_error(req, "No 'force' argument");
 420                 return;
 421         }
 422
 423         for (i = 0; i < *nargs; i++) {
 424                 snprintf(param, sizeof(param), "arg%d", i);
 425                 name = gctl_get_asciiparam(req, param);
 426                 if (name == NULL) {
 427                         gctl_error(req, "No 'arg%d' argument", i);
 428                         return;
 429                 }
 430                 if (strncmp(name, "/dev/", strlen("/dev/")) == 0)
 431                         name += strlen("/dev/");
 432                 gp = g_mountver_find_geom(mp, name);
 433                 if (gp == NULL) {
 434                         G_MOUNTVER_DEBUG(1, "Device %s is invalid.", name);
 435                         gctl_error(req, "Device %s is invalid.", name);
 436                         return;
 437                 }
 438                 error = g_mountver_destroy(gp, *force);
 439                 if (error != 0) {
 440                         gctl_error(req, "Cannot destroy device %s (error=%d).",
 441                             gp->name, error);
 442                         return;
 443                 }
 444         }
 445 }
 446
 447 static void
 448 g_mountver_orphan(struct g_consumer *cp)
 449 {
 450         struct g_mountver_softc *sc;
 451
 452         g_topology_assert();
 453
 454         sc = cp->geom->softc;
 455         sc->sc_orphaned = 1;
 456         if (cp->acr > 0 || cp->acw > 0 || cp->ace > 0)
 457                 g_access(cp, -cp->acr, -cp->acw, -cp->ace);
 458         g_detach(cp);
 459         G_MOUNTVER_DEBUG(0, "%s is offline.  Mount verification in progress.", sc->sc_provider_name);
 460 }
 461
 462 static void
 463 g_mountver_resize(struct g_consumer *cp)
 464 {
 465         struct g_geom *gp;
 466         struct g_provider *pp;
 467
 468         gp = cp->geom;
 469
 470         LIST_FOREACH(pp, &gp->provider, provider)
 471                 g_resize_provider(pp, cp->provider->mediasize);
 472 }
 473
 474 static int
 475 g_mountver_ident_matches(struct g_geom *gp)
 476 {
 477         struct g_consumer *cp;
 478         struct g_mountver_softc *sc;
 479         char ident[DISK_IDENT_SIZE];
 480         int error, identsize = DISK_IDENT_SIZE;
 481
 482         sc = gp->softc;
 483         cp = LIST_FIRST(&gp->consumer);
 484
 485         if (g_mountver_check_ident == 0)
 486                 return (0);
 487
 488         error = g_access(cp, 1, 0, 0);
 489         if (error != 0) {
 490                 G_MOUNTVER_DEBUG(0, "Cannot access %s; "
 491                     "not attaching; error = %d.", gp->name, error);
 492                 return (1);
 493         }
 494         error = g_io_getattr("GEOM::ident", cp, &identsize, ident);
 495         g_access(cp, -1, 0, 0);
 496         if (error != 0) {
 497                 G_MOUNTVER_DEBUG(0, "Cannot get disk ident for %s; "
 498                     "not attaching; error = %d.", gp->name, error);
 499                 return (1);
 500         }
 501         if (strcmp(ident, sc->sc_ident) != 0) {
 502                 G_MOUNTVER_DEBUG(1, "Disk ident for %s (\"%s\") is different "
 503                     "from expected \"%s\", not attaching.", gp->name, ident,
 504                     sc->sc_ident);
 505                 return (1);
 506         }
 507
 508         return (0);
 509 }
 510
 511 static struct g_geom *
 512 g_mountver_taste(struct g_class *mp, struct g_provider *pp, int flags __unused)
 513 {
 514         struct g_mountver_softc *sc;
 515         struct g_consumer *cp;
 516         struct g_geom *gp;
 517         int error;
 518
 519         g_topology_assert();
 520         g_trace(G_T_TOPOLOGY, "%s(%s, %s)", __func__, mp->name, pp->name);
 521         G_MOUNTVER_DEBUG(2, "Tasting %s.", pp->name);
 522
 523         /*
 524          * Let's check if device already exists.
 525          */
 526         LIST_FOREACH(gp, &mp->geom, geom) {
 527                 sc = gp->softc;
 528                 if (sc == NULL)
 529                         continue;
 530
 531                 /* Already attached? */
 532                 if (pp == LIST_FIRST(&gp->provider))
 533                         return (NULL);
 534
 535                 if (sc->sc_orphaned && strcmp(pp->name, sc->sc_provider_name) == 0)
 536                         break;
 537         }
 538         if (gp == NULL)
 539                 return (NULL);
 540
 541         cp = LIST_FIRST(&gp->consumer);
 542         g_attach(cp, pp);
 543         error = g_mountver_ident_matches(gp);
 544         if (error != 0) {
 545                 g_detach(cp);
 546                 return (NULL);
 547         }
 548         if (sc->sc_access_r > 0 || sc->sc_access_w > 0 || sc->sc_access_e > 0) {
 549                 error = g_access(cp, sc->sc_access_r, sc->sc_access_w, sc->sc_access_e);
 550                 if (error != 0) {
 551                         G_MOUNTVER_DEBUG(0, "Cannot access %s; error = %d.", pp->name, error);
 552                         g_detach(cp);
 553                         return (NULL);
 554                 }
 555         }
 556         g_mountver_send_queued(gp);
 557         sc->sc_orphaned = 0;
 558         G_MOUNTVER_DEBUG(0, "%s has completed mount verification.", sc->sc_provider_name);
 559
 560         return (gp);
 561 }
 562
 563 static void
 564 g_mountver_config(struct gctl_req *req, struct g_class *mp, const char *verb)
 565 {
 566         uint32_t *version;
 567
 568         g_topology_assert();
 569
 570         version = gctl_get_paraml(req, "version", sizeof(*version));
 571         if (version == NULL) {
 572                 gctl_error(req, "No '%s' argument.", "version");
 573                 return;
 574         }
 575         if (*version != G_MOUNTVER_VERSION) {
 576                 gctl_error(req, "Userland and kernel parts are out of sync.");
 577                 return;
 578         }
 579
 580         if (strcmp(verb, "create") == 0) {
 581                 g_mountver_ctl_create(req, mp);
 582                 return;
 583         } else if (strcmp(verb, "destroy") == 0) {
 584                 g_mountver_ctl_destroy(req, mp);
 585                 return;
 586         }
 587
 588         gctl_error(req, "Unknown verb.");
 589 }
 590
 591 static void
 592 g_mountver_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp,
 593     struct g_consumer *cp, struct g_provider *pp)
 594 {
 595         struct g_mountver_softc *sc;
 596
 597         if (pp != NULL || cp != NULL)
 598                 return;
 599
 600         sc = gp->softc;
 601         sbuf_printf(sb, "%s<State>%s</State>\n", indent,
 602             sc->sc_orphaned ? "OFFLINE" : "ONLINE");
 603         sbuf_printf(sb, "%s<Provider-Name>%s</Provider-Name>\n", indent, sc->sc_provider_name);
 604         sbuf_printf(sb, "%s<Disk-Ident>%s</Disk-Ident>\n", indent, sc->sc_ident);
 605 }
 606
 607 static void
 608 g_mountver_shutdown_pre_sync(void *arg, int howto)
 609 {
 610         struct g_class *mp;
 611         struct g_geom *gp, *gp2;
 612
 613         mp = arg;
 614         DROP_GIANT();
 615         g_topology_lock();
 616         LIST_FOREACH_SAFE(gp, &mp->geom, geom, gp2)
 617                 g_mountver_destroy(gp, 1);
 618         g_topology_unlock();
 619         PICKUP_GIANT();
 620 }
 621
 622 static void
 623 g_mountver_init(struct g_class *mp)
 624 {
 625
 626         g_mountver_pre_sync = EVENTHANDLER_REGISTER(shutdown_pre_sync,
 627             g_mountver_shutdown_pre_sync, mp, SHUTDOWN_PRI_FIRST);
 628         if (g_mountver_pre_sync == NULL)
 629                 G_MOUNTVER_DEBUG(0, "Warning! Cannot register shutdown event.");
 630 }
 631
 632 static void
 633 g_mountver_fini(struct g_class *mp)
 634 {
 635
 636         if (g_mountver_pre_sync != NULL)
 637                 EVENTHANDLER_DEREGISTER(shutdown_pre_sync, g_mountver_pre_sync);
 638 }
 639
 640 DECLARE_GEOM_CLASS(g_mountver_class, g_mountver);