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