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(int devnum, char *devname, char *attr)
  61 {
  62         char fname[50];
  63         int fd;
  64         char *mdname = devnum2devname(devnum);
  65
  66         if (!mdname)
  67                 return -1;
  68
  69         sprintf(fname, "/sys/block/%s/md/", mdname);
  70         if (devname) {
  71                 strcat(fname, devname);
  72                 strcat(fname, "/");
  73         }
  74         strcat(fname, attr);
  75         fd = open(fname, O_RDWR);
  76         if (fd < 0 && errno == EACCES)
  77                 fd = open(fname, O_RDONLY);
  78         free(mdname);
  79         return fd;
  80 }
  81
  82 void sysfs_init(struct mdinfo *mdi, int fd, int devnum)
  83 {
  84         mdi->sys_name[0] = 0;
  85         if (fd >= 0) {
  86                 mdu_version_t vers;
  87                 if (ioctl(fd, RAID_VERSION, &vers) != 0)
  88                         return;
  89                 devnum = fd2devnum(fd);
  90         }
  91         if (devnum == NoMdDev)
  92                 return;
  93         fmt_devname(mdi->sys_name, devnum);
  94 }
  95
  96
  97 struct mdinfo *sysfs_read(int fd, int devnum, unsigned long options)
  98 {
  99         char fname[PATH_MAX];
 100         char buf[PATH_MAX];
 101         char *base;
 102         char *dbase;
 103         struct mdinfo *sra;
 104         struct mdinfo *dev;
 105         DIR *dir = NULL;
 106         struct dirent *de;
 107
 108         sra = xcalloc(1, sizeof(*sra));
 109         sysfs_init(sra, fd, devnum);
 110         if (sra->sys_name[0] == 0) {
 111                 free(sra);
 112                 return NULL;
 113         }
 114
 115         sprintf(fname, "/sys/block/%s/md/", sra->sys_name);
 116         base = fname + strlen(fname);
 117
 118         sra->devs = NULL;
 119         if (options & GET_VERSION) {
 120                 strcpy(base, "metadata_version");
 121                 if (load_sys(fname, buf))
 122                         goto abort;
 123                 if (strncmp(buf, "none", 4) == 0) {
 124                         sra->array.major_version =
 125                                 sra->array.minor_version = -1;
 126                         strcpy(sra->text_version, "");
 127                 } else if (strncmp(buf, "external:", 9) == 0) {
 128                         sra->array.major_version = -1;
 129                         sra->array.minor_version = -2;
 130                         strcpy(sra->text_version, buf+9);
 131                 } else {
 132                         sscanf(buf, "%d.%d",
 133                                &sra->array.major_version,
 134                                &sra->array.minor_version);
 135                         strcpy(sra->text_version, buf);
 136                 }
 137         }
 138         if (options & GET_LEVEL) {
 139                 strcpy(base, "level");
 140                 if (load_sys(fname, buf))
 141                         goto abort;
 142                 sra->array.level = map_name(pers, buf);
 143         }
 144         if (options & GET_LAYOUT) {
 145                 strcpy(base, "layout");
 146                 if (load_sys(fname, buf))
 147                         goto abort;
 148                 sra->array.layout = strtoul(buf, NULL, 0);
 149         }
 150         if (options & GET_DISKS) {
 151                 strcpy(base, "raid_disks");
 152                 if (load_sys(fname, buf))
 153                         goto abort;
 154                 sra->array.raid_disks = strtoul(buf, NULL, 0);
 155         }
 156         if (options & GET_DEGRADED) {
 157                 strcpy(base, "degraded");
 158                 if (load_sys(fname, buf))
 159                         goto abort;
 160                 sra->array.failed_disks = strtoul(buf, NULL, 0);
 161         }
 162         if (options & GET_COMPONENT) {
 163                 strcpy(base, "component_size");
 164                 if (load_sys(fname, buf))
 165                         goto abort;
 166                 sra->component_size = strtoull(buf, NULL, 0);
 167                 /* sysfs reports "K", but we want sectors */
 168                 sra->component_size *= 2;
 169         }
 170         if (options & GET_CHUNK) {
 171                 strcpy(base, "chunk_size");
 172                 if (load_sys(fname, buf))
 173                         goto abort;
 174                 sra->array.chunk_size = strtoul(buf, NULL, 0);
 175         }
 176         if (options & GET_CACHE) {
 177                 strcpy(base, "stripe_cache_size");
 178                 if (load_sys(fname, buf))
 179                         /* Probably level doesn't support it */
 180                         sra->cache_size = 0;
 181                 else
 182                         sra->cache_size = strtoul(buf, NULL, 0);
 183         }
 184         if (options & GET_MISMATCH) {
 185                 strcpy(base, "mismatch_cnt");
 186                 if (load_sys(fname, buf))
 187                         goto abort;
 188                 sra->mismatch_cnt = strtoul(buf, NULL, 0);
 189         }
 190         if (options & GET_SAFEMODE) {
 191                 int scale = 1;
 192                 int dot = 0;
 193                 unsigned i;
 194                 unsigned long msec;
 195                 size_t len;
 196
 197                 strcpy(base, "safe_mode_delay");
 198                 if (load_sys(fname, buf))
 199                         goto abort;
 200
 201                 /* remove a period, and count digits after it */
 202                 len = strlen(buf);
 203                 for (i = 0; i < len; i++) {
 204                         if (dot) {
 205                                 if (isdigit(buf[i])) {
 206                                         buf[i-1] = buf[i];
 207                                         scale *= 10;
 208                                 }
 209                                 buf[i] = 0;
 210                         } else if (buf[i] == '.') {
 211                                 dot=1;
 212                                 buf[i] = 0;
 213                         }
 214                 }
 215                 msec = strtoul(buf, NULL, 10);
 216                 msec = (msec * 1000) / scale;
 217                 sra->safe_mode_delay = msec;
 218         }
 219         if (options & GET_BITMAP_LOCATION) {
 220                 strcpy(base, "bitmap/location");
 221                 if (load_sys(fname, buf))
 222                         goto abort;
 223                 if (strncmp(buf, "file", 4) == 0)
 224                         sra->bitmap_offset = 1;
 225                 else if (strncmp(buf, "none", 4) == 0)
 226                         sra->bitmap_offset = 0;
 227                 else if (buf[0] == '+')
 228                         sra->bitmap_offset = strtol(buf+1, NULL, 10);
 229                 else
 230                         goto abort;
 231         }
 232
 233         if (! (options & GET_DEVS))
 234                 return sra;
 235
 236         /* Get all the devices as well */
 237         *base = 0;
 238         dir = opendir(fname);
 239         if (!dir)
 240                 goto abort;
 241         sra->array.spare_disks = 0;
 242
 243         while ((de = readdir(dir)) != NULL) {
 244                 char *ep;
 245                 if (de->d_ino == 0 ||
 246                     strncmp(de->d_name, "dev-", 4) != 0)
 247                         continue;
 248                 strcpy(base, de->d_name);
 249                 dbase = base + strlen(base);
 250                 *dbase++ = '/';
 251
 252                 dev = xmalloc(sizeof(*dev));
 253
 254                 /* Always get slot, major, minor */
 255                 strcpy(dbase, "slot");
 256                 if (load_sys(fname, buf)) {
 257                         /* hmm... unable to read 'slot' maybe the device
 258                          * is going away?
 259                          */
 260                         strcpy(dbase, "block");
 261                         if (readlink(fname, buf, sizeof(buf)) < 0 &&
 262                             errno != ENAMETOOLONG) {
 263                                 /* ...yup device is gone */
 264                                 free(dev);
 265                                 continue;
 266                         } else {
 267                                 /* slot is unreadable but 'block' link
 268                                  * still intact... something bad is happening
 269                                  * so abort
 270                                  */
 271                                 free(dev);
 272                                 goto abort;
 273                         }
 274
 275                 }
 276                 strcpy(dev->sys_name, de->d_name);
 277                 dev->disk.raid_disk = strtoul(buf, &ep, 10);
 278                 if (*ep) dev->disk.raid_disk = -1;
 279
 280                 strcpy(dbase, "block/dev");
 281                 if (load_sys(fname, buf)) {
 282                         /* assume this is a stale reference to a hot
 283                          * removed device
 284                          */
 285                         free(dev);
 286                         continue;
 287                 }
 288                 sscanf(buf, "%d:%d", &dev->disk.major, &dev->disk.minor);
 289
 290                 /* special case check for block devices that can go 'offline' */
 291                 strcpy(dbase, "block/device/state");
 292                 if (load_sys(fname, buf) == 0 &&
 293                     strncmp(buf, "offline", 7) == 0) {
 294                         free(dev);
 295                         continue;
 296                 }
 297
 298                 /* finally add this disk to the array */
 299                 dev->next = sra->devs;
 300                 sra->devs = dev;
 301
 302                 if (options & GET_OFFSET) {
 303                         strcpy(dbase, "offset");
 304                         if (load_sys(fname, buf))
 305                                 goto abort;
 306                         dev->data_offset = strtoull(buf, NULL, 0);
 307                         strcpy(dbase, "new_offset");
 308                         if (load_sys(fname, buf) == 0)
 309                                 dev->new_data_offset = strtoull(buf, NULL, 0);
 310                         else
 311                                 dev->new_data_offset = dev->data_offset;
 312                 }
 313                 if (options & GET_SIZE) {
 314                         strcpy(dbase, "size");
 315                         if (load_sys(fname, buf))
 316                                 goto abort;
 317                         dev->component_size = strtoull(buf, NULL, 0) * 2;
 318                 }
 319                 if (options & GET_STATE) {
 320                         dev->disk.state = 0;
 321                         strcpy(dbase, "state");
 322                         if (load_sys(fname, buf))
 323                                 goto abort;
 324                         if (strstr(buf, "in_sync"))
 325                                 dev->disk.state |= (1<<MD_DISK_SYNC);
 326                         if (strstr(buf, "faulty"))
 327                                 dev->disk.state |= (1<<MD_DISK_FAULTY);
 328                         if (dev->disk.state == 0)
 329                                 sra->array.spare_disks++;
 330                 }
 331                 if (options & GET_ERROR) {
 332                         strcpy(buf, "errors");
 333                         if (load_sys(fname, buf))
 334                                 goto abort;
 335                         dev->errors = strtoul(buf, NULL, 0);
 336                 }
 337         }
 338         closedir(dir);
 339         return sra;
 340
 341  abort:
 342         if (dir)
 343                 closedir(dir);
 344         sysfs_free(sra);
 345         return NULL;
 346 }
 347
 348 int sysfs_attr_match(const char *attr, const char *str)
 349 {
 350         /* See if attr, read from a sysfs file, matches
 351          * str.  They must either be the same, or attr can
 352          * have a trailing newline or comma
 353          */
 354         while (*attr && *str && *attr == *str) {
 355                 attr++;
 356                 str++;
 357         }
 358
 359         if (*str || (*attr && *attr != ',' && *attr != '\n'))
 360                 return 0;
 361         return 1;
 362 }
 363
 364 int sysfs_match_word(const char *word, char **list)
 365 {
 366         int n;
 367         for (n=0; list[n]; n++)
 368                 if (sysfs_attr_match(word, list[n]))
 369                         break;
 370         return n;
 371 }
 372
 373 unsigned long long get_component_size(int fd)
 374 {
 375         /* Find out the component size of the array.
 376          * We cannot trust GET_ARRAY_INFO ioctl as it's
 377          * size field is only 32bits.
 378          * So look in /sys/block/mdXXX/md/component_size
 379          *
 380          * This returns in units of sectors.
 381          */
 382         struct stat stb;
 383         char fname[50];
 384         int n;
 385         if (fstat(fd, &stb)) return 0;
 386         if (major(stb.st_rdev) != (unsigned)get_mdp_major())
 387                 sprintf(fname, "/sys/block/md%d/md/component_size",
 388                         (int)minor(stb.st_rdev));
 389         else
 390                 sprintf(fname, "/sys/block/md_d%d/md/component_size",
 391                         (int)minor(stb.st_rdev)>>MdpMinorShift);
 392         fd = open(fname, O_RDONLY);
 393         if (fd < 0)
 394                 return 0;
 395         n = read(fd, fname, sizeof(fname));
 396         close(fd);
 397         if (n < 0 || n == sizeof(fname))
 398                 return 0;
 399         fname[n] = 0;
 400         return strtoull(fname, NULL, 10) * 2;
 401 }
 402
 403 int sysfs_set_str(struct mdinfo *sra, struct mdinfo *dev,
 404                   char *name, char *val)
 405 {
 406         char fname[50];
 407         unsigned int n;
 408         int fd;
 409
 410         sprintf(fname, "/sys/block/%s/md/%s/%s",
 411                 sra->sys_name, dev?dev->sys_name:"", name);
 412         fd = open(fname, O_WRONLY);
 413         if (fd < 0)
 414                 return -1;
 415         n = write(fd, val, strlen(val));
 416         close(fd);
 417         if (n != strlen(val)) {
 418                 dprintf(Name ": failed to write '%s' to '%s' (%s)\n",
 419                         val, fname, strerror(errno));
 420                 return -1;
 421         }
 422         return 0;
 423 }
 424
 425 int sysfs_set_num(struct mdinfo *sra, struct mdinfo *dev,
 426                   char *name, unsigned long long val)
 427 {
 428         char valstr[50];
 429         sprintf(valstr, "%llu", val);
 430         return sysfs_set_str(sra, dev, name, valstr);
 431 }
 432
 433 int sysfs_set_num_signed(struct mdinfo *sra, struct mdinfo *dev,
 434                          char *name, long long val)
 435 {
 436         char valstr[50];
 437         sprintf(valstr, "%lli", val);
 438         return sysfs_set_str(sra, dev, name, valstr);
 439 }
 440
 441 int sysfs_uevent(struct mdinfo *sra, char *event)
 442 {
 443         char fname[50];
 444         int n;
 445         int fd;
 446
 447         sprintf(fname, "/sys/block/%s/uevent",
 448                 sra->sys_name);
 449         fd = open(fname, O_WRONLY);
 450         if (fd < 0)
 451                 return -1;
 452         n = write(fd, event, strlen(event));
 453         close(fd);
 454         if (n != (int)strlen(event)) {
 455                 dprintf(Name ": failed to write '%s' to '%s' (%s)\n",
 456                         event, fname, strerror(errno));
 457                 return -1;
 458         }
 459         return 0;
 460 }
 461
 462 int sysfs_attribute_available(struct mdinfo *sra, struct mdinfo *dev, char *name)
 463 {
 464         char fname[50];
 465         struct stat st;
 466
 467         sprintf(fname, "/sys/block/%s/md/%s/%s",
 468                 sra->sys_name, dev?dev->sys_name:"", name);
 469
 470         return stat(fname, &st) == 0;
 471 }
 472
 473 int sysfs_get_fd(struct mdinfo *sra, struct mdinfo *dev,
 474                        char *name)
 475 {
 476         char fname[50];
 477         int fd;
 478
 479         sprintf(fname, "/sys/block/%s/md/%s/%s",
 480                 sra->sys_name, dev?dev->sys_name:"", name);
 481         fd = open(fname, O_RDWR);
 482         if (fd < 0)
 483                 fd = open(fname, O_RDONLY);
 484         return fd;
 485 }
 486
 487 int sysfs_fd_get_ll(int fd, unsigned long long *val)
 488 {
 489         char buf[50];
 490         int n;
 491         char *ep;
 492
 493         lseek(fd, 0, 0);
 494         n = read(fd, buf, sizeof(buf));
 495         if (n <= 0)
 496                 return -2;
 497         buf[n] = 0;
 498         *val = strtoull(buf, &ep, 0);
 499         if (ep == buf || (*ep != 0 && *ep != '\n' && *ep != ' '))
 500                 return -1;
 501         return 0;
 502 }
 503
 504 int sysfs_get_ll(struct mdinfo *sra, struct mdinfo *dev,
 505                        char *name, unsigned long long *val)
 506 {
 507         int n;
 508         int fd;
 509
 510         fd = sysfs_get_fd(sra, dev, name);
 511         if (fd < 0)
 512                 return -1;
 513         n = sysfs_fd_get_ll(fd, val);
 514         close(fd);
 515         return n;
 516 }
 517
 518 int sysfs_fd_get_str(int fd, char *val, int size)
 519 {
 520         int n;
 521
 522         lseek(fd, 0, 0);
 523         n = read(fd, val, size);
 524         if (n <= 0)
 525                 return -1;
 526         val[n] = 0;
 527         return n;
 528 }
 529
 530 int sysfs_get_str(struct mdinfo *sra, struct mdinfo *dev,
 531                        char *name, char *val, int size)
 532 {
 533         int n;
 534         int fd;
 535
 536         fd = sysfs_get_fd(sra, dev, name);
 537         if (fd < 0)
 538                 return -1;
 539         n = sysfs_fd_get_str(fd, val, size);
 540         close(fd);
 541         return n;
 542 }
 543
 544 int sysfs_set_safemode(struct mdinfo *sra, unsigned long ms)
 545 {
 546         unsigned long sec;
 547         unsigned long msec;
 548         char delay[30];
 549
 550         sec = ms / 1000;
 551         msec = ms % 1000;
 552
 553         sprintf(delay, "%ld.%03ld\n", sec, msec);
 554         /*             this '\n' ^ needed for kernels older than 2.6.28 */
 555         return sysfs_set_str(sra, NULL, "safe_mode_delay", delay);
 556 }
 557
 558 int sysfs_set_array(struct mdinfo *info, int vers)
 559 {
 560         int rv = 0;
 561         char ver[100];
 562         int raid_disks = info->array.raid_disks;
 563
 564         ver[0] = 0;
 565         if (info->array.major_version == -1 &&
 566             info->array.minor_version == -2) {
 567                 char buf[1024];
 568
 569                 strcat(strcpy(ver, "external:"), info->text_version);
 570
 571                 /* meta version might already be set if we are setting
 572                  * new geometry for a reshape.  In that case we don't
 573                  * want to over-write the 'readonly' flag that is
 574                  * stored in the metadata version.  So read the current
 575                  * version first, and preserve the flag
 576                  */
 577                 if (sysfs_get_str(info, NULL, "metadata_version",
 578                                   buf, 1024) > 0)
 579                         if (strlen(buf) >= 9 && buf[9] == '-')
 580                                 ver[9] = '-';
 581
 582                 if ((vers % 100) < 2 ||
 583                     sysfs_set_str(info, NULL, "metadata_version",
 584                                   ver) < 0) {
 585                         pr_err("This kernel does not "
 586                                 "support external metadata.\n");
 587                         return 1;
 588                 }
 589         }
 590         if (info->array.level < 0)
 591                 return 0; /* FIXME */
 592         rv |= sysfs_set_str(info, NULL, "level",
 593                             map_num(pers, info->array.level));
 594         if (info->reshape_active && info->delta_disks != UnSet)
 595                 raid_disks -= info->delta_disks;
 596         rv |= sysfs_set_num(info, NULL, "raid_disks", raid_disks);
 597         rv |= sysfs_set_num(info, NULL, "chunk_size", info->array.chunk_size);
 598         rv |= sysfs_set_num(info, NULL, "layout", info->array.layout);
 599         rv |= sysfs_set_num(info, NULL, "component_size", info->component_size/2);
 600         if (info->custom_array_size) {
 601                 int rc;
 602
 603                 rc = sysfs_set_num(info, NULL, "array_size",
 604                                    info->custom_array_size/2);
 605                 if (rc && errno == ENOENT) {
 606                         pr_err("This kernel does not "
 607                                 "have the md/array_size attribute, "
 608                                 "the array may be larger than expected\n");
 609                         rc = 0;
 610                 }
 611                 rv |= rc;
 612         }
 613
 614         if (info->array.level > 0)
 615                 rv |= sysfs_set_num(info, NULL, "resync_start", info->resync_start);
 616
 617         if (info->reshape_active) {
 618                 rv |= sysfs_set_num(info, NULL, "reshape_position",
 619                                     info->reshape_progress);
 620                 rv |= sysfs_set_num(info, NULL, "chunk_size", info->new_chunk);
 621                 rv |= sysfs_set_num(info, NULL, "layout", info->new_layout);
 622                 rv |= sysfs_set_num(info, NULL, "raid_disks",
 623                                     info->array.raid_disks);
 624                 /* We don't set 'new_level' here.  That can only happen
 625                  * once the reshape completes.
 626                  */
 627         }
 628         return rv;
 629 }
 630
 631 int sysfs_add_disk(struct mdinfo *sra, struct mdinfo *sd, int resume)
 632 {
 633         char dv[PATH_MAX];
 634         char nm[PATH_MAX];
 635         char *dname;
 636         int rv;
 637
 638         sprintf(dv, "%d:%d", sd->disk.major, sd->disk.minor);
 639         rv = sysfs_set_str(sra, NULL, "new_dev", dv);
 640         if (rv)
 641                 return rv;
 642
 643         memset(nm, 0, sizeof(nm));
 644         sprintf(dv, "/sys/dev/block/%d:%d", sd->disk.major, sd->disk.minor);
 645         rv = readlink(dv, nm, sizeof(nm)-1);
 646         if (rv <= 0)
 647                 return -1;
 648         nm[rv] = '\0';
 649         dname = strrchr(nm, '/');
 650         if (dname) dname++;
 651         strcpy(sd->sys_name, "dev-");
 652         strcpy(sd->sys_name+4, dname);
 653
 654         /* test write to see if 'recovery_start' is available */
 655         if (resume && sd->recovery_start < MaxSector &&
 656             sysfs_set_num(sra, sd, "recovery_start", 0)) {
 657                 sysfs_set_str(sra, sd, "state", "remove");
 658                 return -1;
 659         }
 660
 661         rv = sysfs_set_num(sra, sd, "offset", sd->data_offset);
 662         rv |= sysfs_set_num(sra, sd, "size", (sd->component_size+1) / 2);
 663         if (sra->array.level != LEVEL_CONTAINER) {
 664                 if (sd->recovery_start == MaxSector)
 665                         /* This can correctly fail if array isn't started,
 666                          * yet, so just ignore status for now.
 667                          */
 668                         sysfs_set_str(sra, sd, "state", "insync");
 669                 if (sd->disk.raid_disk >= 0)
 670                         rv |= sysfs_set_num(sra, sd, "slot", sd->disk.raid_disk);
 671                 if (resume)
 672                         sysfs_set_num(sra, sd, "recovery_start", sd->recovery_start);
 673         }
 674         return rv;
 675 }
 676
 677 #if 0
 678 int sysfs_disk_to_sg(int fd)
 679 {
 680         /* from an open block device, try find and open its corresponding
 681          * scsi_generic interface
 682          */
 683         struct stat st;
 684         char path[256];
 685         char sg_path[256];
 686         char sg_major_minor[8];
 687         char *c;
 688         DIR *dir;
 689         struct dirent *de;
 690         int major, minor, rv;
 691
 692         if (fstat(fd, &st))
 693                 return -1;
 694
 695         snprintf(path, sizeof(path), "/sys/dev/block/%d:%d/device",
 696                  major(st.st_rdev), minor(st.st_rdev));
 697
 698         dir = opendir(path);
 699         if (!dir)
 700                 return -1;
 701
 702         de = readdir(dir);
 703         while (de) {
 704                 if (strncmp("scsi_generic:", de->d_name,
 705                             strlen("scsi_generic:")) == 0)
 706                         break;
 707                 de = readdir(dir);
 708         }
 709         closedir(dir);
 710
 711         if (!de)
 712                 return -1;
 713
 714         snprintf(sg_path, sizeof(sg_path), "%s/%s/dev", path, de->d_name);
 715         fd = open(sg_path, O_RDONLY);
 716         if (fd < 0)
 717                 return fd;
 718
 719         rv = read(fd, sg_major_minor, sizeof(sg_major_minor));
 720         close(fd);
 721         if (rv < 0)
 722                 return -1;
 723         else
 724                 sg_major_minor[rv - 1] = '\0';
 725
 726         c = strchr(sg_major_minor, ':');
 727         *c = '\0';
 728         c++;
 729         major = strtol(sg_major_minor, NULL, 10);
 730         minor = strtol(c, NULL, 10);
 731         snprintf(path, sizeof(path), "/dev/.tmp.md.%d:%d:%d",
 732                  (int) getpid(), major, minor);
 733         if (mknod(path, S_IFCHR|0600, makedev(major, minor))==0) {
 734                         fd = open(path, O_RDONLY);
 735                         unlink(path);
 736                         return fd;
 737         }
 738
 739         return -1;
 740 }
 741 #endif
 742
 743 int sysfs_disk_to_scsi_id(int fd, __u32 *id)
 744 {
 745         /* from an open block device, try to retrieve it scsi_id */
 746         struct stat st;
 747         char path[256];
 748         DIR *dir;
 749         struct dirent *de;
 750         int host, bus, target, lun;
 751
 752         if (fstat(fd, &st))
 753                 return 1;
 754
 755         snprintf(path, sizeof(path), "/sys/dev/block/%d:%d/device/scsi_device",
 756                  major(st.st_rdev), minor(st.st_rdev));
 757
 758         dir = opendir(path);
 759         if (!dir)
 760                 return 1;
 761
 762         for (de = readdir(dir); de; de = readdir(dir)) {
 763                 int count;
 764
 765                 if (de->d_type != DT_DIR)
 766                         continue;
 767
 768                 count = sscanf(de->d_name, "%d:%d:%d:%d", &host, &bus, &target, &lun);
 769                 if (count == 4)
 770                         break;
 771         }
 772         closedir(dir);
 773
 774         if (!de)
 775                 return 1;
 776
 777         *id = (host << 24) | (bus << 16) | (target << 8) | (lun << 0);
 778         return 0;
 779 }
 780
 781
 782 int sysfs_unique_holder(int devnum, long rdev)
 783 {
 784         /* Check that devnum is a holder of rdev,
 785          * and is the only holder.
 786          * we should be locked against races by
 787          * an O_EXCL on devnum
 788          * Return values:
 789          *  0 - not unique, not even a holder
 790          *  1 - unique, this is the only holder.
 791          *  2/3 - not unique, there is another holder
 792          * -1 - error, cannot find the holders
 793          */
 794         DIR *dir;
 795         struct dirent *de;
 796         char dirname[100];
 797         char l;
 798         int ret = 0;
 799         sprintf(dirname, "/sys/dev/block/%d:%d/holders",
 800                 major(rdev), minor(rdev));
 801         dir = opendir(dirname);
 802         if (!dir)
 803                 return -1;
 804         l = strlen(dirname);
 805         while ((de = readdir(dir)) != NULL) {
 806                 char buf[10];
 807                 int n;
 808                 int mj, mn;
 809                 char c;
 810                 int fd;
 811
 812                 if (de->d_ino == 0)
 813                         continue;
 814                 if (de->d_name[0] == '.')
 815                         continue;
 816                 strcpy(dirname+l, "/");
 817                 strcat(dirname+l, de->d_name);
 818                 strcat(dirname+l, "/dev");
 819                 fd = open(dirname, O_RDONLY);
 820                 if (fd < 0) {
 821                         /* Probably a race, just ignore this */
 822                         continue;
 823                 }
 824                 n = read(fd, buf, sizeof(buf)-1);
 825                 close(fd);
 826                 if (n < 0)
 827                         continue;
 828                 buf[n] = 0;
 829                 if (sscanf(buf, "%d:%d%c", &mj, &mn, &c) != 3 ||
 830                     c != '\n')
 831                         continue;
 832                 if (mj != MD_MAJOR)
 833                         mn = -1-(mn>>6);
 834
 835                 if (devnum == mn)
 836                         ret |= 1;
 837                 else
 838                         ret |= 2;
 839         }
 840         closedir(dir);
 841         return ret;
 842 }
 843
 844 int sysfs_freeze_array(struct mdinfo *sra)
 845 {
 846         /* Try to freeze resync/rebuild on this array/container.
 847          * Return -1 if the array is busy,
 848          * return 0 if this kernel doesn't support 'frozen'
 849          * return 1 if it worked.
 850          */
 851         char buf[20];
 852
 853         if (!sysfs_attribute_available(sra, NULL, "sync_action"))
 854                 return 1; /* no sync_action == frozen */
 855         if (sysfs_get_str(sra, NULL, "sync_action", buf, 20) <= 0)
 856                 return 0;
 857         if (strcmp(buf, "frozen\n") == 0)
 858                 /* Already frozen */
 859                 return 0;
 860         if (strcmp(buf, "idle\n") != 0)
 861                 return -1;
 862         if (sysfs_set_str(sra, NULL, "sync_action", "frozen") < 0)
 863                 return 0;
 864         return 1;
 865 }