Assemble.c

   1 /*
   2  * mdadm - manage Linux "md" devices aka RAID arrays.
   3  *
   4  * Copyright (C) 2001-2002 Neil Brown <neilb@cse.unsw.edu.au>
   5  *
   6  *
   7  *    This program is free software; you can redistribute it and/or modify
   8  *    it under the terms of the GNU General Public License as published by
   9  *    the Free Software Foundation; either version 2 of the License, or
  10  *    (at your option) any later version.
  11  *
  12  *    This program is distributed in the hope that it will be useful,
  13  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *    GNU General Public License for more details.
  16  *
  17  *    You should have received a copy of the GNU General Public License
  18  *    along with this program; if not, write to the Free Software
  19  *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  *
  21  *    Author: Neil Brown
  22  *    Email: <neilb@cse.unsw.edu.au>
  23  *    Paper: Neil Brown
  24  *           School of Computer Science and Engineering
  25  *           The University of New South Wales
  26  *           Sydney, 2052
  27  *           Australia
  28  */
  29
  30 #include        "mdadm.h"
  31
  32 int Assemble(struct supertype *st, char *mddev, int mdfd,
  33              mddev_ident_t ident, char *conffile,
  34              mddev_dev_t devlist,
  35              int readonly, int runstop,
  36              char *update,
  37              int verbose, int force)
  38 {
  39         /*
  40          * The task of Assemble is to find a collection of
  41          * devices that should (according to their superblocks)
  42          * form an array, and to give this collection to the MD driver.
  43          * In Linux-2.4 and later, this involves submitting a
  44          * SET_ARRAY_INFO ioctl with no arg - to prepare
  45          * the array - and then submit a number of
  46          * ADD_NEW_DISK ioctls to add disks into
  47          * the array.  Finally RUN_ARRAY might
  48          * be submitted to start the array.
  49          *
  50          * Much of the work of Assemble is in finding and/or
  51          * checking the disks to make sure they look right.
  52          *
  53          * If mddev is not set, then scan must be set and we
  54          *  read through the config file for dev+uuid mapping
  55          *  We recurse, setting mddev, for each device that
  56          *    - isn't running
  57          *    - has a valid uuid (or any uuid if !uuidset)
  58          *
  59          * If mddev is set, we try to determine state of md.
  60          *   check version - must be at least 0.90.0
  61          *   check kernel version.  must be at least 2.4.
  62          *    If not, we can possibly fall back on START_ARRAY
  63          *   Try to GET_ARRAY_INFO.
  64          *     If possible, give up
  65          *     If not, try to STOP_ARRAY just to make sure
  66          *
  67          * If !uuidset and scan, look in conf-file for uuid
  68          *       If not found, give up
  69          * If !devlist and scan and uuidset, get list of devs from conf-file
  70          *
  71          * For each device:
  72          *   Check superblock - discard if bad
  73          *   Check uuid (set if we don't have one) - discard if no match
  74          *   Check superblock similarity if we have a superblock - discard if different
  75          *   Record events, devicenum
  76          * This should give us a list of devices for the array
  77          * We should collect the most recent event number
  78          *
  79          * Count disks with recent enough event count
  80          * While force && !enough disks
  81          *    Choose newest rejected disks, update event count
  82          *     mark clean and rewrite superblock
  83          * If recent kernel:
  84          *    SET_ARRAY_INFO
  85          *    foreach device with recent events : ADD_NEW_DISK
  86          *    if runstop == 1 || "enough" disks and runstop==0 -> RUN_ARRAY
  87          * If old kernel:
  88          *    Check the device numbers in superblock are right
  89          *    update superblock if any changes
  90          *    START_ARRAY
  91          *
  92          */
  93         int old_linux = 0;
  94         int vers;
  95         void *first_super = NULL, *super = NULL;
  96         struct {
  97                 char *devname;
  98                 unsigned int major, minor;
  99                 unsigned int oldmajor, oldminor;
 100                 long long events;
 101                 int uptodate;
 102                 int state;
 103                 int raid_disk;
 104         } *devices;
 105         int *best = NULL; /* indexed by raid_disk */
 106         unsigned int bestcnt = 0;
 107         int devcnt = 0;
 108         unsigned int okcnt, sparecnt;
 109         unsigned int req_cnt;
 110         unsigned int i;
 111         int most_recent = 0;
 112         int chosen_drive;
 113         int change = 0;
 114         int inargv = 0;
 115         int start_partial_ok = force || devlist==NULL;
 116         unsigned int num_devs;
 117         mddev_dev_t tmpdev;
 118         struct mdinfo info;
 119
 120         vers = md_get_version(mdfd);
 121         if (vers <= 0) {
 122                 fprintf(stderr, Name ": %s appears not to be an md device.\n", mddev);
 123                 return 1;
 124         }
 125         if (vers < 9000) {
 126                 fprintf(stderr, Name ": Assemble requires driver version 0.90.0 or later.\n"
 127                         "    Upgrade your kernel or try --build\n");
 128                 return 1;
 129         }
 130         if (get_linux_version() < 2004000)
 131                 old_linux = 1;
 132
 133         if (ioctl(mdfd, GET_ARRAY_INFO, &info.array)>=0) {
 134                 fprintf(stderr, Name ": device %s already active - cannot assemble it\n",
 135                         mddev);
 136                 return 1;
 137         }
 138         ioctl(mdfd, STOP_ARRAY, NULL); /* just incase it was started but has no content */
 139
 140         /*
 141          * If any subdevs are listed, then any that don't
 142          * match ident are discarded.  Remainder must all match and
 143          * become the array.
 144          * If no subdevs, then we scan all devices in the config file, but
 145          * there must be something in the identity
 146          */
 147
 148         if (!devlist &&
 149             ident->uuid_set == 0 &&
 150             ident->super_minor < 0 &&
 151             ident->devices == NULL) {
 152                 fprintf(stderr, Name ": No identity information available for %s - cannot assemble.\n",
 153                         mddev);
 154                 return 1;
 155         }
 156         if (devlist == NULL)
 157                 devlist = conf_get_devs(conffile);
 158         else inargv = 1;
 159
 160         tmpdev = devlist; num_devs = 0;
 161         while (tmpdev) {
 162                 num_devs++;
 163                 tmpdev = tmpdev->next;
 164         }
 165         devices = malloc(num_devs * sizeof(*devices));
 166
 167         if (!st && ident->st) st = ident->st;
 168
 169         if (verbose)
 170             fprintf(stderr, Name ": looking for devices for %s\n",
 171                     mddev);
 172
 173         while ( devlist) {
 174                 char *devname;
 175                 int dfd;
 176                 struct stat stb;
 177                 struct supertype *tst = st;
 178
 179                 devname = devlist->devname;
 180                 devlist = devlist->next;
 181
 182                 if (ident->devices &&
 183                     !match_oneof(ident->devices, devname)) {
 184                         if (inargv || verbose)
 185                                 fprintf(stderr, Name ": %s is not one of %s\n", devname, ident->devices);
 186                         continue;
 187                 }
 188
 189                 if (super) {
 190                         free(super);
 191                         super = NULL;
 192                 }
 193
 194                 dfd = open(devname, O_RDONLY|O_EXCL, 0);
 195                 if (dfd < 0) {
 196                         if (inargv || verbose)
 197                                 fprintf(stderr, Name ": cannot open device %s: %s\n",
 198                                         devname, strerror(errno));
 199                 } else if (fstat(dfd, &stb)< 0) {
 200                         /* Impossible! */
 201                         fprintf(stderr, Name ": fstat failed for %s: %s\n",
 202                                 devname, strerror(errno));
 203                         close(dfd);
 204                 } else if ((stb.st_mode & S_IFMT) != S_IFBLK) {
 205                         fprintf(stderr, Name ": %s is not a block device.\n",
 206                                 devname);
 207                         close(dfd);
 208                 } else if (!tst && (tst = guess_super(dfd)) == NULL) {
 209                         if (inargv || verbose)
 210                                 fprintf(stderr, Name ": no recogniseable superblock\n");
 211                 } else if (tst->ss->load_super(tst,dfd, &super, NULL)) {
 212                         if (inargv || verbose)
 213                                 fprintf( stderr, Name ": no RAID superblock on %s\n",
 214                                          devname);
 215                         close(dfd);
 216                 } else {
 217                         tst->ss->getinfo_super(&info, super);
 218                         close(dfd);
 219                 }
 220
 221                 if (ident->uuid_set &&
 222                     (!super || same_uuid(info.uuid, ident->uuid, tst->ss->swapuuid)==0)) {
 223                         if (inargv || verbose)
 224                                 fprintf(stderr, Name ": %s has wrong uuid.\n",
 225                                         devname);
 226                         continue;
 227                 }
 228                 if (ident->super_minor != UnSet &&
 229                     (!super || ident->super_minor != info.array.md_minor)) {
 230                         if (inargv || verbose)
 231                                 fprintf(stderr, Name ": %s has wrong super-minor.\n",
 232                                         devname);
 233                         continue;
 234                 }
 235                 if (ident->level != UnSet &&
 236                     (!super|| ident->level != info.array.level)) {
 237                         if (inargv || verbose)
 238                                 fprintf(stderr, Name ": %s has wrong raid level.\n",
 239                                         devname);
 240                         continue;
 241                 }
 242                 if (ident->raid_disks != UnSet &&
 243                     (!super || ident->raid_disks!= info.array.raid_disks)) {
 244                         if (inargv || verbose)
 245                                 fprintf(stderr, Name ": %s requires wrong number of drives.\n",
 246                                         devname);
 247                         continue;
 248                 }
 249
 250                 /* If we are this far, then we are commited to this device.
 251                  * If the super_block doesn't exist, or doesn't match others,
 252                  * then we cannot continue
 253                  */
 254
 255                 if (!super) {
 256                         fprintf(stderr, Name ": %s has no superblock - assembly aborted\n",
 257                                 devname);
 258                         free(first_super);
 259                         return 1;
 260                 }
 261                 st = tst; /* commit to this format, if haven't already */
 262                 if (st->ss->compare_super(&first_super, super)) {
 263                         fprintf(stderr, Name ": superblock on %s doesn't match others - assembly aborted\n",
 264                                 devname);
 265                         free(super);
 266                         free(first_super);
 267                         return 1;
 268                 }
 269
 270                 /* looks like a good enough match to update the super block if needed */
 271                 if (update) {
 272                         /* prepare useful information in info structures */
 273                         struct stat stb2;
 274                         fstat(mdfd, &stb2);
 275                         info.array.md_minor = minor(stb2.st_rdev);
 276
 277                         st->ss->update_super(&info, super, update, devname, verbose);
 278
 279                         dfd = open(devname, O_RDWR|O_EXCL, 0);
 280                         if (dfd < 0)
 281                                 fprintf(stderr, Name ": Cannot open %s for superblock update\n",
 282                                         devname);
 283                         else if (st->ss->store_super(st, dfd, super))
 284                                 fprintf(stderr, Name ": Could not re-write superblock on %s.\n",
 285                                         devname);
 286                         if (dfd >= 0)
 287                                 close(dfd);
 288                 }
 289
 290                 if (verbose)
 291                         fprintf(stderr, Name ": %s is identified as a member of %s, slot %d.\n",
 292                                 devname, mddev, info.disk.raid_disk);
 293                 devices[devcnt].devname = devname;
 294                 devices[devcnt].major = major(stb.st_rdev);
 295                 devices[devcnt].minor = minor(stb.st_rdev);
 296                 devices[devcnt].oldmajor = info.disk.major;
 297                 devices[devcnt].oldminor = info.disk.minor;
 298                 devices[devcnt].events = info.events;
 299                 devices[devcnt].raid_disk = info.disk.raid_disk;
 300                 devices[devcnt].uptodate = 0;
 301                 devices[devcnt].state = info.disk.state;
 302                 if (most_recent < devcnt) {
 303                         if (devices[devcnt].events
 304                             > devices[most_recent].events)
 305                                 most_recent = devcnt;
 306                 }
 307                 if (info.array.level == -4)
 308                         /* with multipath, the raid_disk from the superblock is meaningless */
 309                         i = devcnt;
 310                 else
 311                         i = devices[devcnt].raid_disk;
 312                 if (i < 10000) {
 313                         if (i >= bestcnt) {
 314                                 unsigned int newbestcnt = i+10;
 315                                 int *newbest = malloc(sizeof(int)*newbestcnt);
 316                                 unsigned int c;
 317                                 for (c=0; c < newbestcnt; c++)
 318                                         if (c < bestcnt)
 319                                                 newbest[c] = best[c];
 320                                         else
 321                                                 newbest[c] = -1;
 322                                 if (best)free(best);
 323                                 best = newbest;
 324                                 bestcnt = newbestcnt;
 325                         }
 326                         if (best[i] == -1
 327                             || devices[best[i]].events < devices[devcnt].events)
 328                                 best[i] = devcnt;
 329                 }
 330                 devcnt++;
 331         }
 332
 333         if (super)
 334                 free(super);
 335         super = NULL;
 336
 337         if (update && strcmp(update, "byteorder")==0)
 338                 st->minor_version = 90;
 339
 340         if (devcnt == 0) {
 341                 fprintf(stderr, Name ": no devices found for %s\n",
 342                         mddev);
 343                 free(first_super);
 344                 return 1;
 345         }
 346
 347         st->ss->getinfo_super(&info, first_super);
 348
 349         /* now we have some devices that might be suitable.
 350          * I wonder how many
 351          */
 352         okcnt = 0;
 353         sparecnt=0;
 354         for (i=0; i< bestcnt ;i++) {
 355                 int j = best[i];
 356                 int event_margin = !force;
 357                 if (j < 0) continue;
 358                 /* note: we ignore error flags in multipath arrays
 359                  * as they don't make sense
 360                  */
 361                 if (info.array.level != -4)
 362                         if (!(devices[j].state & (1<<MD_DISK_SYNC))) {
 363                                 if (!(devices[j].state & (1<<MD_DISK_FAULTY)))
 364                                         sparecnt++;
 365                                 continue;
 366                         }
 367                 if (devices[j].events+event_margin >=
 368                     devices[most_recent].events) {
 369                         devices[j].uptodate = 1;
 370                         if (i < info.array.raid_disks)
 371                                 okcnt++;
 372                         else
 373                                 sparecnt++;
 374                 }
 375         }
 376         while (force && !enough(info.array.level, info.array.raid_disks, okcnt)) {
 377                 /* Choose the newest best drive which is
 378                  * not up-to-date, update the superblock
 379                  * and add it.
 380                  */
 381                 int fd;
 382                 chosen_drive = -1;
 383                 for (i=0; i<info.array.raid_disks && i < bestcnt; i++) {
 384                         int j = best[i];
 385                         if (j>=0 &&
 386                             !devices[j].uptodate &&
 387                             devices[j].events > 0 &&
 388                             (chosen_drive < 0 ||
 389                              devices[j].events > devices[chosen_drive].events))
 390                                 chosen_drive = j;
 391                 }
 392                 if (chosen_drive < 0)
 393                         break;
 394                 fprintf(stderr, Name ": forcing event count in %s(%d) from %d upto %d\n",
 395                         devices[chosen_drive].devname, devices[chosen_drive].raid_disk,
 396                         (int)(devices[chosen_drive].events),
 397                         (int)(devices[most_recent].events));
 398                 fd = open(devices[chosen_drive].devname, O_RDWR|O_EXCL);
 399                 if (fd < 0) {
 400                         fprintf(stderr, Name ": Couldn't open %s for write - not updating\n",
 401                                 devices[chosen_drive].devname);
 402                         devices[chosen_drive].events = 0;
 403                         continue;
 404                 }
 405                 if (st->ss->load_super(st,fd, &super, NULL)) {
 406                         close(fd);
 407                         fprintf(stderr, Name ": RAID superblock disappeared from %s - not updating.\n",
 408                                 devices[chosen_drive].devname);
 409                         devices[chosen_drive].events = 0;
 410                         continue;
 411                 }
 412                 info.events = devices[most_recent].events;
 413                 st->ss->update_super(&info, super, "force", devices[chosen_drive].devname, verbose);
 414
 415                 if (st->ss->store_super(st, fd, super)) {
 416                         close(fd);
 417                         fprintf(stderr, Name ": Could not re-write superblock on %s\n",
 418                                 devices[chosen_drive].devname);
 419                         devices[chosen_drive].events = 0;
 420                         free(super);
 421                         continue;
 422                 }
 423                 close(fd);
 424                 devices[chosen_drive].events = devices[most_recent].events;
 425                 devices[chosen_drive].uptodate = 1;
 426                 okcnt++;
 427                 free(super);
 428         }
 429
 430         /* Now we want to look at the superblock which the kernel will base things on
 431          * and compare the devices that we think are working with the devices that the
 432          * superblock thinks are working.
 433          * If there are differences and --force is given, then update this chosen
 434          * superblock.
 435          */
 436         chosen_drive = -1;
 437         super = NULL;
 438         for (i=0; chosen_drive < 0 && i<bestcnt; i++) {
 439                 int j = best[i];
 440                 int fd;
 441
 442                 if (j<0)
 443                         continue;
 444                 if (!devices[j].uptodate)
 445                         continue;
 446                 chosen_drive = j;
 447                 if ((fd=open(devices[j].devname, O_RDONLY|O_EXCL))< 0) {
 448                         fprintf(stderr, Name ": Cannot open %s: %s\n",
 449                                 devices[j].devname, strerror(errno));
 450                         return 1;
 451                 }
 452                 if (st->ss->load_super(st,fd, &super, NULL)) {
 453                         close(fd);
 454                         fprintf(stderr, Name ": RAID superblock has disappeared from %s\n",
 455                                 devices[j].devname);
 456                         return 1;
 457                 }
 458                 close(fd);
 459         }
 460         if (super == NULL) {
 461                 fprintf(stderr, Name ": No suitable drives found for %s\n", mddev);
 462                 return 1;
 463         }
 464         st->ss->getinfo_super(&info, super);
 465         for (i=0; i<bestcnt; i++) {
 466                 int j = best[i];
 467                 unsigned int desired_state;
 468
 469                 if (i < info.array.raid_disks)
 470                         desired_state = (1<<MD_DISK_ACTIVE) | (1<<MD_DISK_SYNC);
 471                 else
 472                         desired_state = 0;
 473
 474                 if (j<0)
 475                         continue;
 476                 if (!devices[j].uptodate)
 477                         continue;
 478                 info.disk.number = i;
 479                 info.disk.raid_disk = i;
 480                 info.disk.state = desired_state;
 481
 482                 if (devices[j].uptodate &&
 483                     st->ss->update_super(&info, super, "assemble", NULL, 0)) {
 484                         if (force) {
 485                                 fprintf(stderr, Name ": "
 486                                         "clearing FAULTY flag for device %d in %s for %s\n",
 487                                         j, mddev, devices[j].devname);
 488                                 change = 1;
 489                         } else {
 490                                 fprintf(stderr, Name ": "
 491                                         "device %d in %s has wrong state in superblock, but %s seems ok\n",
 492                                         i, mddev, devices[j].devname);
 493                         }
 494                 }
 495 #if 0
 496                 if (!devices[j].uptodate &&
 497                     !(super.disks[i].state & (1 << MD_DISK_FAULTY))) {
 498                         fprintf(stderr, Name ": devices %d of %s is not marked FAULTY in superblock, but cannot be found\n",
 499                                 i, mddev);
 500                 }
 501 #endif
 502         }
 503         if (force && okcnt == info.array.raid_disks-1) {
 504                 /* FIXME check event count */
 505                 change += st->ss->update_super(&info, super, "force",
 506                                         devices[chosen_drive].devname, 0);
 507         }
 508
 509         if (change) {
 510                 int fd;
 511                 fd = open(devices[chosen_drive].devname, O_RDWR|O_EXCL);
 512                 if (fd < 0) {
 513                         fprintf(stderr, Name ": Could open %s for write - cannot Assemble array.\n",
 514                                 devices[chosen_drive].devname);
 515                         return 1;
 516                 }
 517                 if (st->ss->store_super(st, fd, super)) {
 518                         close(fd);
 519                         fprintf(stderr, Name ": Could not re-write superblock on %s\n",
 520                                 devices[chosen_drive].devname);
 521                         return 1;
 522                 }
 523                 close(fd);
 524         }
 525
 526         /* count number of in-sync devices according to the superblock.
 527          * We must have this number to start the array without -s or -R
 528          */
 529         req_cnt = info.array.working_disks;
 530
 531         /* Almost ready to actually *do* something */
 532         if (!old_linux) {
 533                 int rv;
 534                 if ((vers % 100) >= 1) { /* can use different versions */
 535                         mdu_array_info_t inf;
 536                         memset(&inf, 0, sizeof(inf));
 537                         inf.major_version = st->ss->major;
 538                         inf.minor_version = st->minor_version;
 539                         rv = ioctl(mdfd, SET_ARRAY_INFO, &inf);
 540                 } else
 541                         rv = ioctl(mdfd, SET_ARRAY_INFO, NULL);
 542
 543                 if (rv) {
 544                         fprintf(stderr, Name ": SET_ARRAY_INFO failed for %s: %s\n",
 545                                 mddev, strerror(errno));
 546                         return 1;
 547                 }
 548                 if (ident->bitmap_fd >= 0) {
 549                         if (ioctl(mdfd, SET_BITMAP_FILE, ident->bitmap_fd) != 0) {
 550                                 fprintf(stderr, Name ": SET_BITMAP_FILE failed.\n");
 551                                 return 1;
 552                         }
 553                 }
 554
 555                 /* First, add the raid disks, but add the chosen one last */
 556                 for (i=0; i<= bestcnt; i++) {
 557                         int j;
 558                         if (i < bestcnt) {
 559                                 j = best[i];
 560                                 if (j == chosen_drive)
 561                                         continue;
 562                         } else
 563                                 j = chosen_drive;
 564
 565                         if (j >= 0 /* && devices[j].uptodate */) {
 566                                 mdu_disk_info_t disk;
 567                                 memset(&disk, 0, sizeof(disk));
 568                                 disk.major = devices[j].major;
 569                                 disk.minor = devices[j].minor;
 570                                 if (ioctl(mdfd, ADD_NEW_DISK, &disk)!=0) {
 571                                         fprintf(stderr, Name ": failed to add %s to %s: %s\n",
 572                                                 devices[j].devname,
 573                                                 mddev,
 574                                                 strerror(errno));
 575                                         if (i < info.array.raid_disks || i == bestcnt)
 576                                                 okcnt--;
 577                                         else
 578                                                 sparecnt--;
 579                                 } else if (verbose)
 580                                         fprintf(stderr, Name ": added %s to %s as %d\n",
 581                                                 devices[j].devname, mddev, devices[j].raid_disk);
 582                         } else if (verbose && i < info.array.raid_disks)
 583                                 fprintf(stderr, Name ": no uptodate device for slot %d of %s\n",
 584                                         i, mddev);
 585                 }
 586
 587                 if (runstop == 1 ||
 588                     (runstop == 0 &&
 589                      ( enough(info.array.level, info.array.raid_disks, okcnt) &&
 590                        (okcnt >= req_cnt || start_partial_ok)
 591                              ))) {
 592                         if (ioctl(mdfd, RUN_ARRAY, NULL)==0) {
 593                                 fprintf(stderr, Name ": %s has been started with %d drive%s",
 594                                         mddev, okcnt, okcnt==1?"":"s");
 595                                 if (okcnt < info.array.raid_disks)
 596                                         fprintf(stderr, " (out of %d)", info.array.raid_disks);
 597                                 if (sparecnt)
 598                                         fprintf(stderr, " and %d spare%s", sparecnt, sparecnt==1?"":"s");
 599                                 fprintf(stderr, ".\n");
 600                                 return 0;
 601                         }
 602                         fprintf(stderr, Name ": failed to RUN_ARRAY %s: %s\n",
 603                                 mddev, strerror(errno));
 604                         return 1;
 605                 }
 606                 if (runstop == -1) {
 607                         fprintf(stderr, Name ": %s assembled from %d drive%s, but not started.\n",
 608                                 mddev, okcnt, okcnt==1?"":"s");
 609                         return 0;
 610                 }
 611                 fprintf(stderr, Name ": %s assembled from %d drive%s", mddev, okcnt, okcnt==1?"":"s");
 612                 if (sparecnt)
 613                         fprintf(stderr, " and %d spare%s", sparecnt, sparecnt==1?"":"s");
 614                 if (!enough(info.array.level, info.array.raid_disks, okcnt))
 615                         fprintf(stderr, " - not enough to start the array.\n");
 616                 else {
 617                         if (req_cnt == info.array.raid_disks)
 618                                 fprintf(stderr, " - need all %d to start it", req_cnt);
 619                         else
 620                                 fprintf(stderr, " - need %d of %d to start", req_cnt, info.array.raid_disks);
 621                         fprintf(stderr, " (use --run to insist).\n");
 622                 }
 623                 return 1;
 624         } else {
 625                 /* The "chosen_drive" is a good choice, and if necessary, the superblock has
 626                  * been updated to point to the current locations of devices.
 627                  * so we can just start the array
 628                  */
 629                 unsigned long dev;
 630                 dev = makedev(devices[chosen_drive].major,
 631                             devices[chosen_drive].minor);
 632                 if (ioctl(mdfd, START_ARRAY, dev)) {
 633                     fprintf(stderr, Name ": Cannot start array: %s\n",
 634                             strerror(errno));
 635                 }
 636
 637         }
 638         return 0;
 639 }