sysfs.c

   1 /*
   2  * sysfs - extract md related information from sysfs.  Part of:
   3  * mdadm - manage Linux "md" devices aka RAID arrays.
   4  *
   5  * Copyright (C) 2006-2009 Neil Brown <neilb@suse.de>
   6  *
   7  *
   8  *    This program is free software; you can redistribute it and/or modify
   9  *    it under the terms of the GNU General Public License as published by
  10  *    the Free Software Foundation; either version 2 of the License, or
  11  *    (at your option) any later version.
  12  *
  13  *    This program is distributed in the hope that it will be useful,
  14  *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *    GNU General Public License for more details.
  17  *
  18  *    You should have received a copy of the GNU General Public License
  19  *    along with this program; if not, write to the Free Software
  20  *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  *
  22  *    Author: Neil Brown
  23  *    Email: <neilb@suse.de>
  24  */
  25
  26 #include        "mdadm.h"
  27 #include        <dirent.h>
  28 #include        <ctype.h>
  29
  30 int load_sys(char *path, char *buf)
  31 {
  32         int fd = open(path, O_RDONLY);
  33         int n;
  34         if (fd < 0)
  35                 return -1;
  36         n = read(fd, buf, 1024);
  37         close(fd);
  38         if (n <0 || n >= 1024)
  39                 return -1;
  40         buf[n] = 0;
  41         if (n && buf[n-1] == '\n')
  42                 buf[n-1] = 0;
  43         return 0;
  44 }
  45
  46 void sysfs_free(struct mdinfo *sra)
  47 {
  48         while (sra) {
  49                 struct mdinfo *sra2 = sra->next;
  50                 while (sra->devs) {
  51                         struct mdinfo *d = sra->devs;
  52                         sra->devs = d->next;
  53                         free(d);
  54                 }
  55                 free(sra);
  56                 sra = sra2;
  57         }
  58 }
  59
  60 int sysfs_open(char *devnm, char *devname, char *attr)
  61 {
  62         char fname[50];
  63         int fd;
  64
  65         sprintf(fname, "/sys/block/%s/md/", devnm);
  66         if (devname) {
  67                 strcat(fname, devname);
  68                 strcat(fname, "/");
  69         }
  70         strcat(fname, attr);
  71         fd = open(fname, O_RDWR);
  72         if (fd < 0 && errno == EACCES)
  73                 fd = open(fname, O_RDONLY);
  74         return fd;
  75 }
  76
  77 void sysfs_init(struct mdinfo *mdi, int fd, char *devnm)
  78 {
  79         mdi->sys_name[0] = 0;
  80         if (fd >= 0) {
  81                 mdu_version_t vers;
  82                 if (ioctl(fd, RAID_VERSION, &vers) != 0)
  83                         return;
  84                 devnm = fd2devnm(fd);
  85         }
  86         if (devnm == NULL)
  87                 return;
  88         strcpy(mdi->sys_name, devnm);
  89 }
  90
  91
  92 struct mdinfo *sysfs_read(int fd, char *devnm, unsigned long options)
  93 {
  94         char fname[PATH_MAX];
  95         char buf[PATH_MAX];
  96         char *base;
  97         char *dbase;
  98         struct mdinfo *sra;
  99         struct mdinfo *dev;
 100         DIR *dir = NULL;
 101         struct dirent *de;
 102
 103         sra = xcalloc(1, sizeof(*sra));
 104         sysfs_init(sra, fd, devnm);
 105         if (sra->sys_name[0] == 0) {
 106                 free(sra);
 107                 return NULL;
 108         }
 109
 110         sprintf(fname, "/sys/block/%s/md/", sra->sys_name);
 111         base = fname + strlen(fname);
 112
 113         sra->devs = NULL;
 114         if (options & GET_VERSION) {
 115                 strcpy(base, "metadata_version");
 116                 if (load_sys(fname, buf))
 117                         goto abort;
 118                 if (strncmp(buf, "none", 4) == 0) {
 119                         sra->array.major_version =
 120                                 sra->array.minor_version = -1;
 121                         strcpy(sra->text_version, "");
 122                 } else if (strncmp(buf, "external:", 9) == 0) {
 123                         sra->array.major_version = -1;
 124                         sra->array.minor_version = -2;
 125                         strcpy(sra->text_version, buf+9);
 126                 } else {
 127                         sscanf(buf, "%d.%d",
 128                                &sra->array.major_version,
 129                                &sra->array.minor_version);
 130                         strcpy(sra->text_version, buf);
 131                 }
 132         }
 133         if (options & GET_LEVEL) {
 134                 strcpy(base, "level");
 135                 if (load_sys(fname, buf))
 136                         goto abort;
 137                 sra->array.level = map_name(pers, buf);
 138         }
 139         if (options & GET_LAYOUT) {
 140                 strcpy(base, "layout");
 141                 if (load_sys(fname, buf))
 142                         goto abort;
 143                 sra->array.layout = strtoul(buf, NULL, 0);
 144         }
 145         if (options & GET_DISKS) {
 146                 strcpy(base, "raid_disks");
 147                 if (load_sys(fname, buf))
 148                         goto abort;
 149                 sra->array.raid_disks = strtoul(buf, NULL, 0);
 150         }
 151         if (options & GET_DEGRADED) {
 152                 strcpy(base, "degraded");
 153                 if (load_sys(fname, buf))
 154                         goto abort;
 155                 sra->array.failed_disks = strtoul(buf, NULL, 0);
 156         }
 157         if (options & GET_COMPONENT) {
 158                 strcpy(base, "component_size");
 159                 if (load_sys(fname, buf))
 160                         goto abort;
 161                 sra->component_size = strtoull(buf, NULL, 0);
 162                 /* sysfs reports "K", but we want sectors */
 163                 sra->component_size *= 2;
 164         }
 165         if (options & GET_CHUNK) {
 166                 strcpy(base, "chunk_size");
 167                 if (load_sys(fname, buf))
 168                         goto abort;
 169                 sra->array.chunk_size = strtoul(buf, NULL, 0);
 170         }
 171         if (options & GET_CACHE) {
 172                 strcpy(base, "stripe_cache_size");
 173                 if (load_sys(fname, buf))
 174                         /* Probably level doesn't support it */
 175                         sra->cache_size = 0;
 176                 else
 177                         sra->cache_size = strtoul(buf, NULL, 0);
 178         }
 179         if (options & GET_MISMATCH) {
 180                 strcpy(base, "mismatch_cnt");
 181                 if (load_sys(fname, buf))
 182                         goto abort;
 183                 sra->mismatch_cnt = strtoul(buf, NULL, 0);
 184         }
 185         if (options & GET_SAFEMODE) {
 186                 int scale = 1;
 187                 int dot = 0;
 188                 unsigned i;
 189                 unsigned long msec;
 190                 size_t len;
 191
 192                 strcpy(base, "safe_mode_delay");
 193                 if (load_sys(fname, buf))
 194                         goto abort;
 195
 196                 /* remove a period, and count digits after it */
 197                 len = strlen(buf);
 198                 for (i = 0; i < len; i++) {
 199                         if (dot) {
 200                                 if (isdigit(buf[i])) {
 201                                         buf[i-1] = buf[i];
 202                                         scale *= 10;
 203                                 }
 204                                 buf[i] = 0;
 205                         } else if (buf[i] == '.') {
 206                                 dot=1;
 207                                 buf[i] = 0;
 208                         }
 209                 }
 210                 msec = strtoul(buf, NULL, 10);
 211                 msec = (msec * 1000) / scale;
 212                 sra->safe_mode_delay = msec;
 213         }
 214         if (options & GET_BITMAP_LOCATION) {
 215                 strcpy(base, "bitmap/location");
 216                 if (load_sys(fname, buf))
 217                         goto abort;
 218                 if (strncmp(buf, "file", 4) == 0)
 219                         sra->bitmap_offset = 1;
 220                 else if (strncmp(buf, "none", 4) == 0)
 221                         sra->bitmap_offset = 0;
 222                 else if (buf[0] == '+')
 223                         sra->bitmap_offset = strtol(buf+1, NULL, 10);
 224                 else
 225                         goto abort;
 226         }
 227
 228         if (! (options & GET_DEVS))
 229                 return sra;
 230
 231         /* Get all the devices as well */
 232         *base = 0;
 233         dir = opendir(fname);
 234         if (!dir)
 235                 goto abort;
 236         sra->array.spare_disks = 0;
 237
 238         while ((de = readdir(dir)) != NULL) {
 239                 char *ep;
 240                 if (de->d_ino == 0 ||
 241                     strncmp(de->d_name, "dev-", 4) != 0)
 242                         continue;
 243                 strcpy(base, de->d_name);
 244                 dbase = base + strlen(base);
 245                 *dbase++ = '/';
 246
 247                 dev = xmalloc(sizeof(*dev));
 248
 249                 /* Always get slot, major, minor */
 250                 strcpy(dbase, "slot");
 251                 if (load_sys(fname, buf)) {
 252                         /* hmm... unable to read 'slot' maybe the device
 253                          * is going away?
 254                          */
 255                         strcpy(dbase, "block");
 256                         if (readlink(fname, buf, sizeof(buf)) < 0 &&
 257                             errno != ENAMETOOLONG) {
 258                                 /* ...yup device is gone */
 259                                 free(dev);
 260                                 continue;
 261                         } else {
 262                                 /* slot is unreadable but 'block' link
 263                                  * still intact... something bad is happening
 264                                  * so abort
 265                                  */
 266                                 free(dev);
 267                                 goto abort;
 268                         }
 269
 270                 }
 271                 strcpy(dev->sys_name, de->d_name);
 272                 dev->disk.raid_disk = strtoul(buf, &ep, 10);
 273                 if (*ep) dev->disk.raid_disk = -1;
 274
 275                 strcpy(dbase, "block/dev");
 276                 if (load_sys(fname, buf)) {
 277                         /* assume this is a stale reference to a hot
 278                          * removed device
 279                          */
 280                         free(dev);
 281                         continue;
 282                 }
 283                 sra->array.nr_disks++;
 284                 sscanf(buf, "%d:%d", &dev->disk.major, &dev->disk.minor);
 285
 286                 /* special case check for block devices that can go 'offline' */
 287                 strcpy(dbase, "block/device/state");
 288                 if (load_sys(fname, buf) == 0 &&
 289                     strncmp(buf, "offline", 7) == 0) {
 290                         free(dev);
 291                         continue;
 292                 }
 293
 294                 /* finally add this disk to the array */
 295                 dev->next = sra->devs;
 296                 sra->devs = dev;
 297
 298                 if (options & GET_OFFSET) {
 299                         strcpy(dbase, "offset");
 300                         if (load_sys(fname, buf))
 301                                 goto abort;
 302                         dev->data_offset = strtoull(buf, NULL, 0);
 303                         strcpy(dbase, "new_offset");
 304                         if (load_sys(fname, buf) == 0)
 305                                 dev->new_data_offset = strtoull(buf, NULL, 0);
 306                         else
 307                                 dev->new_data_offset = dev->data_offset;
 308                 }
 309                 if (options & GET_SIZE) {
 310                         strcpy(dbase, "size");
 311                         if (load_sys(fname, buf))
 312                                 goto abort;
 313                         dev->component_size = strtoull(buf, NULL, 0) * 2;
 314                 }
 315                 if (options & GET_STATE) {
 316                         dev->disk.state = 0;
 317                         strcpy(dbase, "state");
 318                         if (load_sys(fname, buf))
 319                                 goto abort;
 320                         if (strstr(buf, "in_sync"))
 321                                 dev->disk.state |= (1<<MD_DISK_SYNC);
 322                         if (strstr(buf, "faulty"))
 323                                 dev->disk.state |= (1<<MD_DISK_FAULTY);
 324                         if (dev->disk.state == 0)
 325                                 sra->array.spare_disks++;
 326                 }
 327                 if (options & GET_ERROR) {
 328                         strcpy(buf, "errors");
 329                         if (load_sys(fname, buf))
 330                                 goto abort;
 331                         dev->errors = strtoul(buf, NULL, 0);
 332                 }
 333         }
 334         closedir(dir);
 335         return sra;
 336
 337  abort:
 338         if (dir)
 339                 closedir(dir);
 340         sysfs_free(sra);
 341         return NULL;
 342 }
 343
 344 int sysfs_attr_match(const char *attr, const char *str)
 345 {
 346         /* See if attr, read from a sysfs file, matches
 347          * str.  They must either be the same, or attr can
 348          * have a trailing newline or comma
 349          */
 350         while (*attr && *str && *attr == *str) {
 351                 attr++;
 352                 str++;
 353         }
 354
 355         if (*str || (*attr && *attr != ',' && *attr != '\n'))
 356                 return 0;
 357         return 1;
 358 }
 359
 360 int sysfs_match_word(const char *word, char **list)
 361 {
 362         int n;
 363         for (n=0; list[n]; n++)
 364                 if (sysfs_attr_match(word, list[n]))
 365                         break;
 366         return n;
 367 }
 368
 369 unsigned long long get_component_size(int fd)
 370 {
 371         /* Find out the component size of the array.
 372          * We cannot trust GET_ARRAY_INFO ioctl as it's
 373          * size field is only 32bits.
 374          * So look in /sys/block/mdXXX/md/component_size
 375          *
 376          * This returns in units of sectors.
 377          */
 378         struct stat stb;
 379         char fname[50];
 380         int n;
 381         if (fstat(fd, &stb)) return 0;
 382         if (major(stb.st_rdev) != (unsigned)get_mdp_major())
 383                 sprintf(fname, "/sys/block/md%d/md/component_size",
 384                         (int)minor(stb.st_rdev));
 385         else
 386                 sprintf(fname, "/sys/block/md_d%d/md/component_size",
 387                         (int)minor(stb.st_rdev)>>MdpMinorShift);
 388         fd = open(fname, O_RDONLY);
 389         if (fd < 0)
 390                 return 0;
 391         n = read(fd, fname, sizeof(fname));
 392         close(fd);
 393         if (n < 0 || n == sizeof(fname))
 394                 return 0;
 395         fname[n] = 0;
 396         return strtoull(fname, NULL, 10) * 2;
 397 }
 398
 399 int sysfs_set_str(struct mdinfo *sra, struct mdinfo *dev,
 400                   char *name, char *val)
 401 {
 402         char fname[50];
 403         unsigned int n;
 404         int fd;
 405
 406         sprintf(fname, "/sys/block/%s/md/%s/%s",
 407                 sra->sys_name, dev?dev->sys_name:"", name);
 408         fd = open(fname, O_WRONLY);
 409         if (fd < 0)
 410                 return -1;
 411         n = write(fd, val, strlen(val));
 412         close(fd);
 413         if (n != strlen(val)) {
 414                 dprintf(Name ": failed to write '%s' to '%s' (%s)\n",
 415                         val, fname, strerror(errno));
 416                 return -1;
 417         }
 418         return 0;
 419 }
 420
 421 int sysfs_set_num(struct mdinfo *sra, struct mdinfo *dev,
 422                   char *name, unsigned long long val)
 423 {
 424         char valstr[50];
 425         sprintf(valstr, "%llu", val);
 426         return sysfs_set_str(sra, dev, name, valstr);
 427 }
 428
 429 int sysfs_set_num_signed(struct mdinfo *sra, struct mdinfo *dev,
 430                          char *name, long long val)
 431 {
 432         char valstr[50];
 433         sprintf(valstr, "%lli", val);
 434         return sysfs_set_str(sra, dev, name, valstr);
 435 }
 436
 437 int sysfs_uevent(struct mdinfo *sra, char *event)
 438 {
 439         char fname[50];
 440         int n;
 441         int fd;
 442
 443         sprintf(fname, "/sys/block/%s/uevent",
 444                 sra->sys_name);
 445         fd = open(fname, O_WRONLY);
 446         if (fd < 0)
 447                 return -1;
 448         n = write(fd, event, strlen(event));
 449         close(fd);
 450         if (n != (int)strlen(event)) {
 451                 dprintf(Name ": failed to write '%s' to '%s' (%s)\n",
 452                         event, fname, strerror(errno));
 453                 return -1;
 454         }
 455         return 0;
 456 }
 457
 458 int sysfs_attribute_available(struct mdinfo *sra, struct mdinfo *dev, char *name)
 459 {
 460         char fname[50];
 461         struct stat st;
 462
 463         sprintf(fname, "/sys/block/%s/md/%s/%s",
 464                 sra->sys_name, dev?dev->sys_name:"", name);
 465
 466         return stat(fname, &st) == 0;
 467 }
 468
 469 int sysfs_get_fd(struct mdinfo *sra, struct mdinfo *dev,
 470                        char *name)
 471 {
 472         char fname[50];
 473         int fd;
 474
 475         sprintf(fname, "/sys/block/%s/md/%s/%s",
 476                 sra->sys_name, dev?dev->sys_name:"", name);
 477         fd = open(fname, O_RDWR);
 478         if (fd < 0)
 479                 fd = open(fname, O_RDONLY);
 480         return fd;
 481 }
 482
 483 int sysfs_fd_get_ll(int fd, unsigned long long *val)
 484 {
 485         char buf[50];
 486         int n;
 487         char *ep;
 488
 489         lseek(fd, 0, 0);
 490         n = read(fd, buf, sizeof(buf));
 491         if (n <= 0)
 492                 return -2;
 493         buf[n] = 0;
 494         *val = strtoull(buf, &ep, 0);
 495         if (ep == buf || (*ep != 0 && *ep != '\n' && *ep != ' '))
 496                 return -1;
 497         return 0;
 498 }
 499
 500 int sysfs_get_ll(struct mdinfo *sra, struct mdinfo *dev,
 501                        char *name, unsigned long long *val)
 502 {
 503         int n;
 504         int fd;
 505
 506         fd = sysfs_get_fd(sra, dev, name);
 507         if (fd < 0)
 508                 return -1;
 509         n = sysfs_fd_get_ll(fd, val);
 510         close(fd);
 511         return n;
 512 }
 513
 514 int sysfs_fd_get_str(int fd, char *val, int size)
 515 {
 516         int n;
 517
 518         lseek(fd, 0, 0);
 519         n = read(fd, val, size);
 520         if (n <= 0)
 521                 return -1;
 522         val[n] = 0;
 523         return n;
 524 }
 525
 526 int sysfs_get_str(struct mdinfo *sra, struct mdinfo *dev,
 527                        char *name, char *val, int size)
 528 {
 529         int n;
 530         int fd;
 531
 532         fd = sysfs_get_fd(sra, dev, name);
 533         if (fd < 0)
 534                 return -1;
 535         n = sysfs_fd_get_str(fd, val, size);
 536         close(fd);
 537         return n;
 538 }
 539
 540 int sysfs_set_safemode(struct mdinfo *sra, unsigned long ms)
 541 {
 542         unsigned long sec;
 543         unsigned long msec;
 544         char delay[30];
 545
 546         sec = ms / 1000;
 547         msec = ms % 1000;
 548
 549         sprintf(delay, "%ld.%03ld\n", sec, msec);
 550         /*             this '\n' ^ needed for kernels older than 2.6.28 */
 551         return sysfs_set_str(sra, NULL, "safe_mode_delay", delay);
 552 }
 553
 554 int sysfs_set_array(struct mdinfo *info, int vers)
 555 {
 556         int rv = 0;
 557         char ver[100];
 558         int raid_disks = info->array.raid_disks;
 559
 560         ver[0] = 0;
 561         if (info->array.major_version == -1 &&
 562             info->array.minor_version == -2) {
 563                 char buf[1024];
 564
 565                 strcat(strcpy(ver, "external:"), info->text_version);
 566
 567                 /* meta version might already be set if we are setting
 568                  * new geometry for a reshape.  In that case we don't
 569                  * want to over-write the 'readonly' flag that is
 570                  * stored in the metadata version.  So read the current
 571                  * version first, and preserve the flag
 572                  */
 573                 if (sysfs_get_str(info, NULL, "metadata_version",
 574                                   buf, 1024) > 0)
 575                         if (strlen(buf) >= 9 && buf[9] == '-')
 576                                 ver[9] = '-';
 577
 578                 if ((vers % 100) < 2 ||
 579                     sysfs_set_str(info, NULL, "metadata_version",
 580                                   ver) < 0) {
 581                         pr_err("This kernel does not "
 582                                 "support external metadata.\n");
 583                         return 1;
 584                 }
 585         }
 586         if (info->array.level < 0)
 587                 return 0; /* FIXME */
 588         rv |= sysfs_set_str(info, NULL, "level",
 589                             map_num(pers, info->array.level));
 590         if (info->reshape_active && info->delta_disks != UnSet)
 591                 raid_disks -= info->delta_disks;
 592         rv |= sysfs_set_num(info, NULL, "raid_disks", raid_disks);
 593         rv |= sysfs_set_num(info, NULL, "chunk_size", info->array.chunk_size);
 594         rv |= sysfs_set_num(info, NULL, "layout", info->array.layout);
 595         rv |= sysfs_set_num(info, NULL, "component_size", info->component_size/2);
 596         if (info->custom_array_size) {
 597                 int rc;
 598
 599                 rc = sysfs_set_num(info, NULL, "array_size",
 600                                    info->custom_array_size/2);
 601                 if (rc && errno == ENOENT) {
 602                         pr_err("This kernel does not "
 603                                 "have the md/array_size attribute, "
 604                                 "the array may be larger than expected\n");
 605                         rc = 0;
 606                 }
 607                 rv |= rc;
 608         }
 609
 610         if (info->array.level > 0)
 611                 rv |= sysfs_set_num(info, NULL, "resync_start", info->resync_start);
 612
 613         if (info->reshape_active) {
 614                 rv |= sysfs_set_num(info, NULL, "reshape_position",
 615                                     info->reshape_progress);
 616                 rv |= sysfs_set_num(info, NULL, "chunk_size", info->new_chunk);
 617                 rv |= sysfs_set_num(info, NULL, "layout", info->new_layout);
 618                 rv |= sysfs_set_num(info, NULL, "raid_disks",
 619                                     info->array.raid_disks);
 620                 /* We don't set 'new_level' here.  That can only happen
 621                  * once the reshape completes.
 622                  */
 623         }
 624         return rv;
 625 }
 626
 627 int sysfs_add_disk(struct mdinfo *sra, struct mdinfo *sd, int resume)
 628 {
 629         char dv[PATH_MAX];
 630         char nm[PATH_MAX];
 631         char *dname;
 632         int rv;
 633
 634         sprintf(dv, "%d:%d", sd->disk.major, sd->disk.minor);
 635         rv = sysfs_set_str(sra, NULL, "new_dev", dv);
 636         if (rv)
 637                 return rv;
 638
 639         memset(nm, 0, sizeof(nm));
 640         dname = devid2devnm(makedev(sd->disk.major, sd->disk.minor));
 641         strcpy(sd->sys_name, "dev-");
 642         strcpy(sd->sys_name+4, dname);
 643
 644         /* test write to see if 'recovery_start' is available */
 645         if (resume && sd->recovery_start < MaxSector &&
 646             sysfs_set_num(sra, sd, "recovery_start", 0)) {
 647                 sysfs_set_str(sra, sd, "state", "remove");
 648                 return -1;
 649         }
 650
 651         rv = sysfs_set_num(sra, sd, "offset", sd->data_offset);
 652         rv |= sysfs_set_num(sra, sd, "size", (sd->component_size+1) / 2);
 653         if (sra->array.level != LEVEL_CONTAINER) {
 654                 if (sd->recovery_start == MaxSector)
 655                         /* This can correctly fail if array isn't started,
 656                          * yet, so just ignore status for now.
 657                          */
 658                         sysfs_set_str(sra, sd, "state", "insync");
 659                 if (sd->disk.raid_disk >= 0)
 660                         rv |= sysfs_set_num(sra, sd, "slot", sd->disk.raid_disk);
 661                 if (resume)
 662                         sysfs_set_num(sra, sd, "recovery_start", sd->recovery_start);
 663         }
 664         return rv;
 665 }
 666
 667 #if 0
 668 int sysfs_disk_to_sg(int fd)
 669 {
 670         /* from an open block device, try find and open its corresponding
 671          * scsi_generic interface
 672          */
 673         struct stat st;
 674         char path[256];
 675         char sg_path[256];
 676         char sg_major_minor[8];
 677         char *c;
 678         DIR *dir;
 679         struct dirent *de;
 680         int major, minor, rv;
 681
 682         if (fstat(fd, &st))
 683                 return -1;
 684
 685         snprintf(path, sizeof(path), "/sys/dev/block/%d:%d/device",
 686                  major(st.st_rdev), minor(st.st_rdev));
 687
 688         dir = opendir(path);
 689         if (!dir)
 690                 return -1;
 691
 692         de = readdir(dir);
 693         while (de) {
 694                 if (strncmp("scsi_generic:", de->d_name,
 695                             strlen("scsi_generic:")) == 0)
 696                         break;
 697                 de = readdir(dir);
 698         }
 699         closedir(dir);
 700
 701         if (!de)
 702                 return -1;
 703
 704         snprintf(sg_path, sizeof(sg_path), "%s/%s/dev", path, de->d_name);
 705         fd = open(sg_path, O_RDONLY);
 706         if (fd < 0)
 707                 return fd;
 708
 709         rv = read(fd, sg_major_minor, sizeof(sg_major_minor));
 710         close(fd);
 711         if (rv < 0)
 712                 return -1;
 713         else
 714                 sg_major_minor[rv - 1] = '\0';
 715
 716         c = strchr(sg_major_minor, ':');
 717         *c = '\0';
 718         c++;
 719         major = strtol(sg_major_minor, NULL, 10);
 720         minor = strtol(c, NULL, 10);
 721         snprintf(path, sizeof(path), "/dev/.tmp.md.%d:%d:%d",
 722                  (int) getpid(), major, minor);
 723         if (mknod(path, S_IFCHR|0600, makedev(major, minor))==0) {
 724                         fd = open(path, O_RDONLY);
 725                         unlink(path);
 726                         return fd;
 727         }
 728
 729         return -1;
 730 }
 731 #endif
 732
 733 int sysfs_disk_to_scsi_id(int fd, __u32 *id)
 734 {
 735         /* from an open block device, try to retrieve it scsi_id */
 736         struct stat st;
 737         char path[256];
 738         DIR *dir;
 739         struct dirent *de;
 740         int host, bus, target, lun;
 741
 742         if (fstat(fd, &st))
 743                 return 1;
 744
 745         snprintf(path, sizeof(path), "/sys/dev/block/%d:%d/device/scsi_device",
 746                  major(st.st_rdev), minor(st.st_rdev));
 747
 748         dir = opendir(path);
 749         if (!dir)
 750                 return 1;
 751
 752         for (de = readdir(dir); de; de = readdir(dir)) {
 753                 int count;
 754
 755                 if (de->d_type != DT_DIR)
 756                         continue;
 757
 758                 count = sscanf(de->d_name, "%d:%d:%d:%d", &host, &bus, &target, &lun);
 759                 if (count == 4)
 760                         break;
 761         }
 762         closedir(dir);
 763
 764         if (!de)
 765                 return 1;
 766
 767         *id = (host << 24) | (bus << 16) | (target << 8) | (lun << 0);
 768         return 0;
 769 }
 770
 771
 772 int sysfs_unique_holder(char *devnm, long rdev)
 773 {
 774         /* Check that devnm is a holder of rdev,
 775          * and is the only holder.
 776          * we should be locked against races by
 777          * an O_EXCL on devnm
 778          * Return values:
 779          *  0 - not unique, not even a holder
 780          *  1 - unique, this is the only holder.
 781          *  2/3 - not unique, there is another holder
 782          * -1 - error, cannot find the holders
 783          */
 784         DIR *dir;
 785         struct dirent *de;
 786         char dirname[100];
 787         char l;
 788         int ret = 0;
 789         sprintf(dirname, "/sys/dev/block/%d:%d/holders",
 790                 major(rdev), minor(rdev));
 791         dir = opendir(dirname);
 792         if (!dir)
 793                 return -1;
 794         l = strlen(dirname);
 795         while ((de = readdir(dir)) != NULL) {
 796                 char buf[100];
 797                 char *sl;
 798                 int n;
 799
 800                 if (de->d_ino == 0)
 801                         continue;
 802                 if (de->d_name[0] == '.')
 803                         continue;
 804                 strcpy(dirname+l, "/");
 805                 strcat(dirname+l, de->d_name);
 806                 n = readlink(dirname, buf, sizeof(buf)-1);
 807                 if (n <= 0)
 808                         continue;
 809                 buf[n] = 0;
 810                 sl = strrchr(buf, '/');
 811                 if (!sl)
 812                         continue;
 813                 sl++;
 814
 815                 if (strcmp(devnm, sl) == 0)
 816                         ret |= 1;
 817                 else
 818                         ret |= 2;
 819         }
 820         closedir(dir);
 821         return ret;
 822 }
 823
 824 int sysfs_freeze_array(struct mdinfo *sra)
 825 {
 826         /* Try to freeze resync/rebuild on this array/container.
 827          * Return -1 if the array is busy,
 828          * return 0 if this kernel doesn't support 'frozen'
 829          * return 1 if it worked.
 830          */
 831         char buf[20];
 832
 833         if (!sysfs_attribute_available(sra, NULL, "sync_action"))
 834                 return 1; /* no sync_action == frozen */
 835         if (sysfs_get_str(sra, NULL, "sync_action", buf, 20) <= 0)
 836                 return 0;
 837         if (strcmp(buf, "frozen\n") == 0)
 838                 /* Already frozen */
 839                 return 0;
 840         if (strcmp(buf, "idle\n") != 0)
 841                 return -1;
 842         if (sysfs_set_str(sra, NULL, "sync_action", "frozen") < 0)
 843                 return 0;
 844         return 1;
 845 }