sys/geom/geom_disk.c

   1 /*-
   2  * Copyright (c) 2002 Poul-Henning Kamp
   3  * Copyright (c) 2002 Networks Associates Technology, Inc.
   4  * All rights reserved.
   5  *
   6  * This software was developed for the FreeBSD Project by Poul-Henning Kamp
   7  * and NAI Labs, the Security Research Division of Network Associates, Inc.
   8  * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
   9  * DARPA CHATS research program.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  * 3. The names of the authors may not be used to endorse or promote
  20  *    products derived from this software without specific prior written
  21  *    permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 #include <sys/cdefs.h>
  37 __FBSDID("$FreeBSD$");
  38
  39 #include "opt_geom.h"
  40
  41 #include <sys/param.h>
  42 #include <sys/systm.h>
  43 #include <sys/kernel.h>
  44 #include <sys/sysctl.h>
  45 #include <sys/bio.h>
  46 #include <sys/ctype.h>
  47 #include <sys/fcntl.h>
  48 #include <sys/malloc.h>
  49 #include <sys/devicestat.h>
  50 #include <machine/md_var.h>
  51
  52 #include <sys/lock.h>
  53 #include <sys/mutex.h>
  54 #include <geom/geom.h>
  55 #include <geom/geom_disk.h>
  56 #include <geom/geom_int.h>
  57
  58 #include <dev/led/led.h>
  59
  60 struct g_disk_softc {
  61         struct disk             *dp;
  62         struct sysctl_ctx_list  sysctl_ctx;
  63         struct sysctl_oid       *sysctl_tree;
  64         char                    led[64];
  65         uint32_t                state;
  66 };
  67
  68 static struct mtx g_disk_done_mtx;
  69
  70 static g_access_t g_disk_access;
  71 static g_init_t g_disk_init;
  72 static g_fini_t g_disk_fini;
  73 static g_start_t g_disk_start;
  74 static g_ioctl_t g_disk_ioctl;
  75 static g_dumpconf_t g_disk_dumpconf;
  76
  77 static struct g_class g_disk_class = {
  78         .name = "DISK",
  79         .version = G_VERSION,
  80         .init = g_disk_init,
  81         .fini = g_disk_fini,
  82         .start = g_disk_start,
  83         .access = g_disk_access,
  84         .ioctl = g_disk_ioctl,
  85         .dumpconf = g_disk_dumpconf,
  86 };
  87
  88 SYSCTL_DECL(_kern_geom);
  89 SYSCTL_NODE(_kern_geom, OID_AUTO, disk, CTLFLAG_RW, 0, "GEOM_DISK stuff");
  90
  91 static void
  92 g_disk_init(struct g_class *mp __unused)
  93 {
  94
  95         mtx_init(&g_disk_done_mtx, "g_disk_done", NULL, MTX_DEF);
  96 }
  97
  98 static void
  99 g_disk_fini(struct g_class *mp __unused)
 100 {
 101
 102         mtx_destroy(&g_disk_done_mtx);
 103 }
 104
 105 DECLARE_GEOM_CLASS(g_disk_class, g_disk);
 106
 107 static void __inline
 108 g_disk_lock_giant(struct disk *dp)
 109 {
 110         if (dp->d_flags & DISKFLAG_NEEDSGIANT)
 111                 mtx_lock(&Giant);
 112 }
 113
 114 static void __inline
 115 g_disk_unlock_giant(struct disk *dp)
 116 {
 117         if (dp->d_flags & DISKFLAG_NEEDSGIANT)
 118                 mtx_unlock(&Giant);
 119 }
 120
 121 static int
 122 g_disk_access(struct g_provider *pp, int r, int w, int e)
 123 {
 124         struct disk *dp;
 125         struct g_disk_softc *sc;
 126         int error;
 127
 128         g_trace(G_T_ACCESS, "g_disk_access(%s, %d, %d, %d)",
 129             pp->name, r, w, e);
 130         g_topology_assert();
 131         sc = pp->geom->softc;
 132         if (sc == NULL || (dp = sc->dp) == NULL || dp->d_destroyed) {
 133                 /*
 134                  * Allow decreasing access count even if disk is not
 135                  * avaliable anymore.
 136                  */
 137                 if (r <= 0 && w <= 0 && e <= 0)
 138                         return (0);
 139                 return (ENXIO);
 140         }
 141         r += pp->acr;
 142         w += pp->acw;
 143         e += pp->ace;
 144         error = 0;
 145         if ((pp->acr + pp->acw + pp->ace) == 0 && (r + w + e) > 0) {
 146                 if (dp->d_open != NULL) {
 147                         g_disk_lock_giant(dp);
 148                         error = dp->d_open(dp);
 149                         if (bootverbose && error != 0)
 150                                 printf("Opened disk %s -> %d\n",
 151                                     pp->name, error);
 152                         g_disk_unlock_giant(dp);
 153                         if (error != 0)
 154                                 return (error);
 155                 }
 156                 pp->mediasize = dp->d_mediasize;
 157                 pp->sectorsize = dp->d_sectorsize;
 158                 if (dp->d_flags & DISKFLAG_CANDELETE)
 159                         pp->flags |= G_PF_CANDELETE;
 160                 else
 161                         pp->flags &= ~G_PF_CANDELETE;
 162                 pp->stripeoffset = dp->d_stripeoffset;
 163                 pp->stripesize = dp->d_stripesize;
 164                 dp->d_flags |= DISKFLAG_OPEN;
 165                 if (dp->d_maxsize == 0) {
 166                         printf("WARNING: Disk drive %s%d has no d_maxsize\n",
 167                             dp->d_name, dp->d_unit);
 168                         dp->d_maxsize = DFLTPHYS;
 169                 }
 170         } else if ((pp->acr + pp->acw + pp->ace) > 0 && (r + w + e) == 0) {
 171                 if (dp->d_close != NULL) {
 172                         g_disk_lock_giant(dp);
 173                         error = dp->d_close(dp);
 174                         if (error != 0)
 175                                 printf("Closed disk %s -> %d\n",
 176                                     pp->name, error);
 177                         g_disk_unlock_giant(dp);
 178                 }
 179                 sc->state = G_STATE_ACTIVE;
 180                 if (sc->led[0] != 0)
 181                         led_set(sc->led, "0");
 182                 dp->d_flags &= ~DISKFLAG_OPEN;
 183         }
 184         return (error);
 185 }
 186
 187 static void
 188 g_disk_kerneldump(struct bio *bp, struct disk *dp)
 189 {
 190         struct g_kerneldump *gkd;
 191         struct g_geom *gp;
 192
 193         gkd = (struct g_kerneldump*)bp->bio_data;
 194         gp = bp->bio_to->geom;
 195         g_trace(G_T_TOPOLOGY, "g_disk_kerneldump(%s, %jd, %jd)",
 196                 gp->name, (intmax_t)gkd->offset, (intmax_t)gkd->length);
 197         if (dp->d_dump == NULL) {
 198                 g_io_deliver(bp, ENODEV);
 199                 return;
 200         }
 201         gkd->di.dumper = dp->d_dump;
 202         gkd->di.priv = dp;
 203         gkd->di.blocksize = dp->d_sectorsize;
 204         gkd->di.maxiosize = dp->d_maxsize;
 205         gkd->di.mediaoffset = gkd->offset;
 206         if ((gkd->offset + gkd->length) > dp->d_mediasize)
 207                 gkd->length = dp->d_mediasize - gkd->offset;
 208         gkd->di.mediasize = gkd->length;
 209         g_io_deliver(bp, 0);
 210 }
 211
 212 static void
 213 g_disk_setstate(struct bio *bp, struct g_disk_softc *sc)
 214 {
 215         const char *cmd;
 216
 217         memcpy(&sc->state, bp->bio_data, sizeof(sc->state));
 218         if (sc->led[0] != 0) {
 219                 switch (sc->state) {
 220                 case G_STATE_FAILED:
 221                         cmd = "1";
 222                         break;
 223                 case G_STATE_REBUILD:
 224                         cmd = "f5";
 225                         break;
 226                 case G_STATE_RESYNC:
 227                         cmd = "f1";
 228                         break;
 229                 default:
 230                         cmd = "0";
 231                         break;
 232                 }
 233                 led_set(sc->led, cmd);
 234         }
 235         g_io_deliver(bp, 0);
 236 }
 237
 238 static void
 239 g_disk_done(struct bio *bp)
 240 {
 241         struct bio *bp2;
 242         struct disk *dp;
 243         struct g_disk_softc *sc;
 244
 245         /* See "notes" for why we need a mutex here */
 246         /* XXX: will witness accept a mix of Giant/unGiant drivers here ? */
 247         mtx_lock(&g_disk_done_mtx);
 248         bp->bio_completed = bp->bio_length - bp->bio_resid;
 249
 250         bp2 = bp->bio_parent;
 251         if (bp2->bio_error == 0)
 252                 bp2->bio_error = bp->bio_error;
 253         bp2->bio_completed += bp->bio_completed;
 254         if ((bp->bio_cmd & (BIO_READ|BIO_WRITE|BIO_DELETE)) &&
 255             (sc = bp2->bio_to->geom->softc) &&
 256             (dp = sc->dp)) {
 257                 devstat_end_transaction_bio(dp->d_devstat, bp);
 258         }
 259         g_destroy_bio(bp);
 260         bp2->bio_inbed++;
 261         if (bp2->bio_children == bp2->bio_inbed) {
 262                 bp2->bio_resid = bp2->bio_bcount - bp2->bio_completed;
 263                 g_io_deliver(bp2, bp2->bio_error);
 264         }
 265         mtx_unlock(&g_disk_done_mtx);
 266 }
 267
 268 static int
 269 g_disk_ioctl(struct g_provider *pp, u_long cmd, void * data, int fflag, struct thread *td)
 270 {
 271         struct g_geom *gp;
 272         struct disk *dp;
 273         struct g_disk_softc *sc;
 274         int error;
 275
 276         gp = pp->geom;
 277         sc = gp->softc;
 278         dp = sc->dp;
 279
 280         if (dp->d_ioctl == NULL)
 281                 return (ENOIOCTL);
 282         g_disk_lock_giant(dp);
 283         error = dp->d_ioctl(dp, cmd, data, fflag, td);
 284         g_disk_unlock_giant(dp);
 285         return(error);
 286 }
 287
 288 static void
 289 g_disk_start(struct bio *bp)
 290 {
 291         struct bio *bp2, *bp3;
 292         struct disk *dp;
 293         struct g_disk_softc *sc;
 294         int error;
 295         off_t off;
 296
 297         sc = bp->bio_to->geom->softc;
 298         if (sc == NULL || (dp = sc->dp) == NULL || dp->d_destroyed) {
 299                 g_io_deliver(bp, ENXIO);
 300                 return;
 301         }
 302         error = EJUSTRETURN;
 303         switch(bp->bio_cmd) {
 304         case BIO_DELETE:
 305                 if (!(dp->d_flags & DISKFLAG_CANDELETE)) {
 306                         error = EOPNOTSUPP;
 307                         break;
 308                 }
 309                 /* fall-through */
 310         case BIO_READ:
 311         case BIO_WRITE:
 312                 off = 0;
 313                 bp3 = NULL;
 314                 bp2 = g_clone_bio(bp);
 315                 if (bp2 == NULL) {
 316                         error = ENOMEM;
 317                         break;
 318                 }
 319                 do {
 320                         bp2->bio_offset += off;
 321                         bp2->bio_length -= off;
 322                         bp2->bio_data += off;
 323                         if (bp2->bio_length > dp->d_maxsize) {
 324                                 /*
 325                                  * XXX: If we have a stripesize we should really
 326                                  * use it here.
 327                                  */
 328                                 bp2->bio_length = dp->d_maxsize;
 329                                 off += dp->d_maxsize;
 330                                 /*
 331                                  * To avoid a race, we need to grab the next bio
 332                                  * before we schedule this one.  See "notes".
 333                                  */
 334                                 bp3 = g_clone_bio(bp);
 335                                 if (bp3 == NULL)
 336                                         bp->bio_error = ENOMEM;
 337                         }
 338                         bp2->bio_done = g_disk_done;
 339                         bp2->bio_pblkno = bp2->bio_offset / dp->d_sectorsize;
 340                         bp2->bio_bcount = bp2->bio_length;
 341                         bp2->bio_disk = dp;
 342                         devstat_start_transaction_bio(dp->d_devstat, bp2);
 343                         g_disk_lock_giant(dp);
 344                         dp->d_strategy(bp2);
 345                         g_disk_unlock_giant(dp);
 346                         bp2 = bp3;
 347                         bp3 = NULL;
 348                 } while (bp2 != NULL);
 349                 break;
 350         case BIO_GETATTR:
 351                 if (g_handleattr_int(bp, "GEOM::candelete",
 352                     (dp->d_flags & DISKFLAG_CANDELETE) != 0))
 353                         break;
 354                 else if (g_handleattr_int(bp, "GEOM::fwsectors",
 355                     dp->d_fwsectors))
 356                         break;
 357                 else if (g_handleattr_int(bp, "GEOM::fwheads", dp->d_fwheads))
 358                         break;
 359                 else if (g_handleattr_off_t(bp, "GEOM::frontstuff", 0))
 360                         break;
 361                 else if (g_handleattr_str(bp, "GEOM::ident", dp->d_ident))
 362                         break;
 363                 else if (!strcmp(bp->bio_attribute, "GEOM::kerneldump"))
 364                         g_disk_kerneldump(bp, dp);
 365                 else if (!strcmp(bp->bio_attribute, "GEOM::setstate"))
 366                         g_disk_setstate(bp, sc);
 367                 else
 368                         error = ENOIOCTL;
 369                 break;
 370         case BIO_FLUSH:
 371                 g_trace(G_T_BIO, "g_disk_flushcache(%s)",
 372                     bp->bio_to->name);
 373                 if (!(dp->d_flags & DISKFLAG_CANFLUSHCACHE)) {
 374                         error = EOPNOTSUPP;
 375                         break;
 376                 }
 377                 bp2 = g_clone_bio(bp);
 378                 if (bp2 == NULL) {
 379                         g_io_deliver(bp, ENOMEM);
 380                         return;
 381                 }
 382                 bp2->bio_done = g_disk_done;
 383                 bp2->bio_disk = dp;
 384                 g_disk_lock_giant(dp);
 385                 dp->d_strategy(bp2);
 386                 g_disk_unlock_giant(dp);
 387                 break;
 388         default:
 389                 error = EOPNOTSUPP;
 390                 break;
 391         }
 392         if (error != EJUSTRETURN)
 393                 g_io_deliver(bp, error);
 394         return;
 395 }
 396
 397 static void
 398 g_disk_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp, struct g_provider *pp)
 399 {
 400         struct disk *dp;
 401         struct g_disk_softc *sc;
 402
 403         sc = gp->softc;
 404         if (sc == NULL || (dp = sc->dp) == NULL)
 405                 return;
 406         if (indent == NULL) {
 407                 sbuf_printf(sb, " hd %u", dp->d_fwheads);
 408                 sbuf_printf(sb, " sc %u", dp->d_fwsectors);
 409                 return;
 410         }
 411         if (pp != NULL) {
 412                 sbuf_printf(sb, "%s<fwheads>%u</fwheads>\n",
 413                     indent, dp->d_fwheads);
 414                 sbuf_printf(sb, "%s<fwsectors>%u</fwsectors>\n",
 415                     indent, dp->d_fwsectors);
 416         }
 417 }
 418
 419 static void
 420 g_disk_create(void *arg, int flag)
 421 {
 422         struct g_geom *gp;
 423         struct g_provider *pp;
 424         struct disk *dp;
 425         struct g_disk_softc *sc;
 426         char tmpstr[80];
 427
 428         if (flag == EV_CANCEL)
 429                 return;
 430         g_topology_assert();
 431         dp = arg;
 432         sc = g_malloc(sizeof(*sc), M_WAITOK | M_ZERO);
 433         sc->dp = dp;
 434         gp = g_new_geomf(&g_disk_class, "%s%d", dp->d_name, dp->d_unit);
 435         gp->softc = sc;
 436         pp = g_new_providerf(gp, "%s", gp->name);
 437         pp->mediasize = dp->d_mediasize;
 438         pp->sectorsize = dp->d_sectorsize;
 439         if (dp->d_flags & DISKFLAG_CANDELETE)
 440                 pp->flags |= G_PF_CANDELETE;
 441         pp->stripeoffset = dp->d_stripeoffset;
 442         pp->stripesize = dp->d_stripesize;
 443         if (bootverbose)
 444                 printf("GEOM: new disk %s\n", gp->name);
 445         sysctl_ctx_init(&sc->sysctl_ctx);
 446         snprintf(tmpstr, sizeof(tmpstr), "GEOM disk %s", gp->name);
 447         sc->sysctl_tree = SYSCTL_ADD_NODE(&sc->sysctl_ctx,
 448                 SYSCTL_STATIC_CHILDREN(_kern_geom_disk), OID_AUTO, gp->name,
 449                 CTLFLAG_RD, 0, tmpstr);
 450         if (sc->sysctl_tree != NULL) {
 451                 snprintf(tmpstr, sizeof(tmpstr),
 452                     "kern.geom.disk.%s.led", gp->name);
 453                 TUNABLE_STR_FETCH(tmpstr, sc->led, sizeof(sc->led));
 454                 SYSCTL_ADD_STRING(&sc->sysctl_ctx,
 455                     SYSCTL_CHILDREN(sc->sysctl_tree), OID_AUTO, "led",
 456                     CTLFLAG_RW | CTLFLAG_TUN, sc->led, sizeof(sc->led),
 457                     "LED name");
 458         }
 459         pp->private = sc;
 460         dp->d_geom = gp;
 461         g_error_provider(pp, 0);
 462 }
 463
 464 static void
 465 g_disk_destroy(void *ptr, int flag)
 466 {
 467         struct disk *dp;
 468         struct g_geom *gp;
 469         struct g_disk_softc *sc;
 470
 471         g_topology_assert();
 472         dp = ptr;
 473         gp = dp->d_geom;
 474         if (gp != NULL) {
 475                 sc = gp->softc;
 476                 if (sc->sysctl_tree != NULL) {
 477                         sysctl_ctx_free(&sc->sysctl_ctx);
 478                         sc->sysctl_tree = NULL;
 479                 }
 480                 if (sc->led[0] != 0) {
 481                         led_set(sc->led, "0");
 482                         sc->led[0] = 0;
 483                 }
 484                 g_free(sc);
 485                 gp->softc = NULL;
 486                 g_wither_geom(gp, ENXIO);
 487         }
 488         g_free(dp);
 489 }
 490
 491 /*
 492  * We only allow printable characters in disk ident,
 493  * the rest is converted to 'x<HH>'.
 494  */
 495 static void
 496 g_disk_ident_adjust(char *ident, size_t size)
 497 {
 498         char *p, tmp[4], newid[DISK_IDENT_SIZE];
 499
 500         newid[0] = '\0';
 501         for (p = ident; *p != '\0'; p++) {
 502                 if (isprint(*p)) {
 503                         tmp[0] = *p;
 504                         tmp[1] = '\0';
 505                 } else {
 506                         snprintf(tmp, sizeof(tmp), "x%02hhx",
 507                             *(unsigned char *)p);
 508                 }
 509                 if (strlcat(newid, tmp, sizeof(newid)) >= sizeof(newid))
 510                         break;
 511         }
 512         bzero(ident, size);
 513         strlcpy(ident, newid, size);
 514 }
 515
 516 struct disk *
 517 disk_alloc()
 518 {
 519         struct disk *dp;
 520
 521         dp = g_malloc(sizeof *dp, M_WAITOK | M_ZERO);
 522         return (dp);
 523 }
 524
 525 void
 526 disk_create(struct disk *dp, int version)
 527 {
 528         if (version != DISK_VERSION_00 && version != DISK_VERSION_01) {
 529                 printf("WARNING: Attempt to add disk %s%d %s",
 530                     dp->d_name, dp->d_unit,
 531                     " using incompatible ABI version of disk(9)\n");
 532                 printf("WARNING: Ignoring disk %s%d\n",
 533                     dp->d_name, dp->d_unit);
 534                 return;
 535         }
 536         KASSERT(dp->d_strategy != NULL, ("disk_create need d_strategy"));
 537         KASSERT(dp->d_name != NULL, ("disk_create need d_name"));
 538         KASSERT(*dp->d_name != 0, ("disk_create need d_name"));
 539         KASSERT(strlen(dp->d_name) < SPECNAMELEN - 4, ("disk name too long"));
 540         if (dp->d_devstat == NULL)
 541                 dp->d_devstat = devstat_new_entry(dp->d_name, dp->d_unit,
 542                     dp->d_sectorsize, DEVSTAT_ALL_SUPPORTED,
 543                     DEVSTAT_TYPE_DIRECT, DEVSTAT_PRIORITY_MAX);
 544         dp->d_geom = NULL;
 545         g_disk_ident_adjust(dp->d_ident, sizeof(dp->d_ident));
 546         g_post_event(g_disk_create, dp, M_WAITOK, dp, NULL);
 547 }
 548
 549 void
 550 disk_destroy(struct disk *dp)
 551 {
 552
 553         g_cancel_event(dp);
 554         dp->d_destroyed = 1;
 555         if (dp->d_devstat != NULL)
 556                 devstat_remove_entry(dp->d_devstat);
 557         g_post_event(g_disk_destroy, dp, M_WAITOK, NULL);
 558 }
 559
 560 void
 561 disk_gone(struct disk *dp)
 562 {
 563         struct g_geom *gp;
 564         struct g_provider *pp;
 565
 566         gp = dp->d_geom;
 567         if (gp != NULL)
 568                 LIST_FOREACH(pp, &gp->provider, provider)
 569                         g_wither_provider(pp, ENXIO);
 570 }
 571
 572 static void
 573 g_kern_disks(void *p, int flag __unused)
 574 {
 575         struct sbuf *sb;
 576         struct g_geom *gp;
 577         char *sp;
 578
 579         sb = p;
 580         sp = "";
 581         g_topology_assert();
 582         LIST_FOREACH(gp, &g_disk_class.geom, geom) {
 583                 sbuf_printf(sb, "%s%s", sp, gp->name);
 584                 sp = " ";
 585         }
 586         sbuf_finish(sb);
 587 }
 588
 589 static int
 590 sysctl_disks(SYSCTL_HANDLER_ARGS)
 591 {
 592         int error;
 593         struct sbuf *sb;
 594
 595         sb = sbuf_new_auto();
 596         g_waitfor_event(g_kern_disks, sb, M_WAITOK, NULL);
 597         error = SYSCTL_OUT(req, sbuf_data(sb), sbuf_len(sb) + 1);
 598         sbuf_delete(sb);
 599         return error;
 600 }
 601
 602 SYSCTL_PROC(_kern, OID_AUTO, disks, CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_NOLOCK, 0, 0,
 603     sysctl_disks, "A", "names of available disks");
 604