raid6check.c

   1 /*
   2  * raid6check - extended consistency check for RAID-6
   3  *
   4  * Copyright (C) 2011 Piergiorgio Sartor
   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: Piergiorgio Sartor
  22  *    Based on "restripe.c" from "mdadm" codebase
  23  */
  24
  25 #include "mdadm.h"
  26 #include "xmalloc.h"
  27 #include <stdint.h>
  28 #include <sys/mman.h>
  29
  30 #define CHECK_PAGE_BITS (12)
  31 #define CHECK_PAGE_SIZE (1 << CHECK_PAGE_BITS)
  32
  33 char const Name[] = "raid6check";
  34
  35 enum repair {
  36         NO_REPAIR = 0,
  37         MANUAL_REPAIR,
  38         AUTO_REPAIR
  39 };
  40
  41 int geo_map(int block, unsigned long long stripe, int raid_disks,
  42             int level, int layout);
  43 int is_ddf(int layout);
  44 void qsyndrome(uint8_t *p, uint8_t *q, uint8_t **sources, int disks, int size);
  45 void make_tables(void);
  46 void ensure_zero_has_size(int chunk_size);
  47 void raid6_datap_recov(int disks, size_t bytes, int faila, uint8_t **ptrs,
  48                        int neg_offset);
  49 void raid6_2data_recov(int disks, size_t bytes, int faila, int failb,
  50                        uint8_t **ptrs, int neg_offset);
  51 void xor_blocks(char *target, char **sources, int disks, int size);
  52
  53 /* Collect per stripe consistency information */
  54 void raid6_collect(int chunk_size, uint8_t *p, uint8_t *q,
  55                    char *chunkP, char *chunkQ, int *results)
  56 {
  57         int i;
  58         int data_id;
  59         uint8_t Px, Qx;
  60         extern uint8_t raid6_gflog[];
  61
  62         for(i = 0; i < chunk_size; i++) {
  63                 Px = (uint8_t)chunkP[i] ^ (uint8_t)p[i];
  64                 Qx = (uint8_t)chunkQ[i] ^ (uint8_t)q[i];
  65
  66                 if((Px != 0) && (Qx == 0))
  67                         results[i] = -1;
  68
  69                 if((Px == 0) && (Qx != 0))
  70                         results[i] = -2;
  71
  72                 if((Px != 0) && (Qx != 0)) {
  73                         data_id = (raid6_gflog[Qx] - raid6_gflog[Px]);
  74                         if(data_id < 0) data_id += 255;
  75                         results[i] = data_id;
  76                 }
  77
  78                 if((Px == 0) && (Qx == 0))
  79                         results[i] = -255;
  80         }
  81 }
  82
  83 /* Try to find out if a specific disk has problems in a CHECK_PAGE_SIZE page size */
  84 int raid6_stats_blk(int *results, int raid_disks)
  85 {
  86         int i;
  87         int curr_broken_disk = -255;
  88         int prev_broken_disk = -255;
  89         int broken_status = 0;
  90
  91         for(i = 0; i < CHECK_PAGE_SIZE; i++) {
  92
  93                 if(results[i] != -255)
  94                         curr_broken_disk = results[i];
  95
  96                 if(curr_broken_disk >= raid_disks)
  97                         broken_status = 2;
  98
  99                 switch(broken_status) {
 100                 case 0:
 101                         if(curr_broken_disk != -255) {
 102                                 prev_broken_disk = curr_broken_disk;
 103                                 broken_status = 1;
 104                         }
 105                         break;
 106
 107                 case 1:
 108                         if(curr_broken_disk != prev_broken_disk)
 109                                 broken_status = 2;
 110                         break;
 111
 112                 case 2:
 113                 default:
 114                         curr_broken_disk = prev_broken_disk = -65535;
 115                         break;
 116                 }
 117         }
 118
 119         return curr_broken_disk;
 120 }
 121
 122 /* Collect disks status for a strip in CHECK_PAGE_SIZE page size blocks */
 123 void raid6_stats(int *disk, int *results, int raid_disks, int chunk_size)
 124 {
 125         int i, j;
 126
 127         for(i = 0, j = 0; i < chunk_size; i += CHECK_PAGE_SIZE, j++) {
 128                 disk[j] = raid6_stats_blk(&results[i], raid_disks);
 129         }
 130 }
 131
 132 int lock_stripe(struct mdinfo *info, unsigned long long start,
 133                 int chunk_size, int data_disks, sighandler_t *sig)
 134 {
 135         int rv;
 136
 137         sig[0] = signal_s(SIGTERM, SIG_IGN);
 138         sig[1] = signal_s(SIGINT, SIG_IGN);
 139         sig[2] = signal_s(SIGQUIT, SIG_IGN);
 140
 141         if (sig[0] == SIG_ERR || sig[1] == SIG_ERR || sig[2] == SIG_ERR)
 142                 return 1;
 143
 144         if(mlockall(MCL_CURRENT | MCL_FUTURE) != 0) {
 145                 return 2;
 146         }
 147
 148         rv = sysfs_set_num(info, NULL, "suspend_lo", start * chunk_size * data_disks);
 149         rv |= sysfs_set_num(info, NULL, "suspend_hi", (start + 1) * chunk_size * data_disks);
 150         return rv * 256;
 151 }
 152
 153 int unlock_all_stripes(struct mdinfo *info, sighandler_t *sig)
 154 {
 155         int rv;
 156         rv = sysfs_set_num(info, NULL, "suspend_lo", 0x7FFFFFFFFFFFFFFFULL);
 157         rv |= sysfs_set_num(info, NULL, "suspend_hi", 0);
 158         rv |= sysfs_set_num(info, NULL, "suspend_lo", 0);
 159
 160         signal_s(SIGQUIT, sig[2]);
 161         signal_s(SIGINT, sig[1]);
 162         signal_s(SIGTERM, sig[0]);
 163
 164         if(munlockall() != 0)
 165                 return 3;
 166         return rv * 256;
 167 }
 168
 169 /* Autorepair */
 170 int autorepair(int *disk, unsigned long long start, int chunk_size,
 171                 char *name[], int raid_disks, int syndrome_disks, char **blocks_page,
 172                 char **blocks, uint8_t *p, int *block_index_for_slot,
 173                 int *source, unsigned long long *offsets)
 174 {
 175         int i, j;
 176         int pages_to_write_count = 0;
 177         int page_to_write[chunk_size >> CHECK_PAGE_BITS];
 178         for(j = 0; j < (chunk_size >> CHECK_PAGE_BITS); j++) {
 179                 if (disk[j] >= -2 && block_index_for_slot[disk[j]] >= 0) {
 180                         int slot = block_index_for_slot[disk[j]];
 181                         printf("Auto-repairing slot %d (%s)\n", slot, name[slot]);
 182                         pages_to_write_count++;
 183                         page_to_write[j] = 1;
 184                         for(i = -2; i < syndrome_disks; i++) {
 185                                 blocks_page[i] = blocks[i] + j * CHECK_PAGE_SIZE;
 186                         }
 187                         if (disk[j] == -2) {
 188                                 qsyndrome(p, (uint8_t*)blocks_page[-2],
 189                                           (uint8_t**)blocks_page,
 190                                           syndrome_disks, CHECK_PAGE_SIZE);
 191                         }
 192                         else {
 193                                 char *all_but_failed_blocks[syndrome_disks];
 194                                 for(i = 0; i < syndrome_disks; i++) {
 195                                         if (i == disk[j])
 196                                                 all_but_failed_blocks[i] = blocks_page[-1];
 197                                         else
 198                                                 all_but_failed_blocks[i] = blocks_page[i];
 199                                 }
 200                                 xor_blocks(blocks_page[disk[j]],
 201                                            all_but_failed_blocks, syndrome_disks,
 202                                            CHECK_PAGE_SIZE);
 203                         }
 204                 }
 205                 else {
 206                         page_to_write[j] = 0;
 207                 }
 208         }
 209
 210         if(pages_to_write_count > 0) {
 211                 int write_res = 0;
 212                 for(j = 0; j < (chunk_size >> CHECK_PAGE_BITS); j++) {
 213                         if(page_to_write[j] == 1) {
 214                                 int slot = block_index_for_slot[disk[j]];
 215                                 lseek(source[slot],
 216                                       offsets[slot] + start * chunk_size +
 217                                       j * CHECK_PAGE_SIZE, SEEK_SET);
 218                                 write_res += write(source[slot],
 219                                                    blocks[disk[j]] +
 220                                                    j * CHECK_PAGE_SIZE,
 221                                                    CHECK_PAGE_SIZE);
 222                         }
 223                 }
 224
 225                 if (write_res != (CHECK_PAGE_SIZE * pages_to_write_count)) {
 226                         fprintf(stderr, "Failed to write a full chunk.\n");
 227                         return -1;
 228                 }
 229         }
 230
 231         return 0;
 232 }
 233
 234 /* Manual repair */
 235 int manual_repair(int chunk_size, int syndrome_disks,
 236                   int failed_slot1, int failed_slot2,
 237                   unsigned long long start, int *block_index_for_slot,
 238                   char *name[], char **stripes, char **blocks, uint8_t *p,
 239                   int *source, unsigned long long *offsets)
 240 {
 241         int i;
 242         int fd1 = block_index_for_slot[failed_slot1];
 243         int fd2 = block_index_for_slot[failed_slot2];
 244         printf("Repairing stripe %llu\n", start);
 245         printf("Assuming slots %d (%s) and %d (%s) are incorrect\n",
 246                fd1, name[fd1],
 247                fd2, name[fd2]);
 248
 249         if (failed_slot1 == -2 || failed_slot2 == -2) {
 250                 char *all_but_failed_blocks[syndrome_disks];
 251                 int failed_data_or_p;
 252
 253                 if (failed_slot1 == -2)
 254                         failed_data_or_p = failed_slot2;
 255                 else
 256                         failed_data_or_p = failed_slot1;
 257
 258                 printf("Repairing D/P(%d) and Q\n", failed_data_or_p);
 259
 260                 for (i = 0; i < syndrome_disks; i++) {
 261                         if (i == failed_data_or_p)
 262                                 all_but_failed_blocks[i] = blocks[-1];
 263                         else
 264                                 all_but_failed_blocks[i] = blocks[i];
 265                 }
 266                 xor_blocks(blocks[failed_data_or_p],
 267                            all_but_failed_blocks, syndrome_disks, chunk_size);
 268                 qsyndrome(p, (uint8_t*)blocks[-2], (uint8_t**)blocks,
 269                           syndrome_disks, chunk_size);
 270         } else {
 271                 ensure_zero_has_size(chunk_size);
 272                 if (failed_slot1 == -1 || failed_slot2 == -1) {
 273                         int failed_data;
 274                         if (failed_slot1 == -1)
 275                                 failed_data = failed_slot2;
 276                         else
 277                                 failed_data = failed_slot1;
 278
 279                         printf("Repairing D(%d) and P\n", failed_data);
 280                         raid6_datap_recov(syndrome_disks+2, chunk_size,
 281                                           failed_data, (uint8_t**)blocks, 1);
 282                 } else {
 283                         printf("Repairing D and D\n");
 284                         raid6_2data_recov(syndrome_disks+2, chunk_size,
 285                                           failed_slot1, failed_slot2,
 286                                           (uint8_t**)blocks, 1);
 287                 }
 288         }
 289
 290         int write_res1, write_res2;
 291         off64_t seek_res;
 292
 293         seek_res = lseek(source[fd1], offsets[fd1] + start * chunk_size, SEEK_SET);
 294         if (seek_res < 0) {
 295                 fprintf(stderr, "lseek failed for failed_disk1\n");
 296                 return -1;
 297         }
 298         write_res1 = write(source[fd1], blocks[failed_slot1], chunk_size);
 299
 300         seek_res = lseek(source[fd2], offsets[fd2] + start * chunk_size, SEEK_SET);
 301         if (seek_res < 0) {
 302                 fprintf(stderr, "lseek failed for failed_disk2\n");
 303                 return -1;
 304         }
 305         write_res2 = write(source[fd2], blocks[failed_slot2], chunk_size);
 306
 307         if (write_res1 != chunk_size || write_res2 != chunk_size) {
 308                 fprintf(stderr, "Failed to write a complete chunk.\n");
 309                 return -2;
 310         }
 311
 312         return 0;
 313 }
 314
 315 int check_stripes(struct mdinfo *info, int *source, unsigned long long *offsets,
 316                   int raid_disks, int chunk_size, int level, int layout,
 317                   unsigned long long start, unsigned long long length, char *name[],
 318                   enum repair repair, int failed_disk1, int failed_disk2)
 319 {
 320         /* read the data and p and q blocks, and check we got them right */
 321         int data_disks = raid_disks - 2;
 322         int syndrome_disks = data_disks + is_ddf(layout) * 2;
 323         char *stripe_buf;
 324
 325         /* stripes[] is indexed by raid_disk and holds chunks from each device */
 326         char **stripes = xmalloc(raid_disks * sizeof(char*));
 327
 328         /* blocks[] is indexed by syndrome number and points to either one of the
 329          * chunks from 'stripes[]', or to a chunk of zeros. -1 and -2 are
 330          * P and Q */
 331         char **blocks = xmalloc((syndrome_disks + 2) * sizeof(char*));
 332
 333         /* blocks_page[] is a temporary index to just one page of the chunks
 334          * that blocks[] points to. */
 335         char **blocks_page = xmalloc((syndrome_disks + 2) * sizeof(char*));
 336
 337         /* block_index_for_slot[] provides the reverse mapping from blocks to stripes.
 338          * The index is a syndrome position, the content is a raid_disk number.
 339          * indicies -1 and -2 work, and are P and Q disks */
 340         int *block_index_for_slot = xmalloc((syndrome_disks+2) * sizeof(int));
 341
 342         /* 'p' and 'q' contain calcualted P and Q, to be compared with
 343          * blocks[-1] and blocks[-2];
 344          */
 345         uint8_t *p = xmalloc(chunk_size);
 346         uint8_t *q = xmalloc(chunk_size);
 347         char *zero = xmalloc(chunk_size);
 348         int *results = xmalloc(chunk_size * sizeof(int));
 349         sighandler_t *sig = xmalloc(3 * sizeof(sighandler_t));
 350
 351         int i, j;
 352         int diskP, diskQ, diskD;
 353         int err = 0;
 354
 355         extern int tables_ready;
 356
 357         if (!tables_ready)
 358                 make_tables();
 359
 360         if (posix_memalign((void**)&stripe_buf, 4096, raid_disks * chunk_size) != 0)
 361                 exit(4);
 362         block_index_for_slot += 2;
 363         blocks += 2;
 364         blocks_page += 2;
 365
 366         memset(zero, 0, chunk_size);
 367         for ( i = 0 ; i < raid_disks ; i++)
 368                 stripes[i] = stripe_buf + i * chunk_size;
 369
 370         while (length > 0) {
 371                 /* The syndrome number of the broken disk is recorded
 372                  * in 'disk[]' which allows a different broken disk for
 373                  * each page.
 374                  */
 375                 int disk[chunk_size >> CHECK_PAGE_BITS];
 376
 377                 err = lock_stripe(info, start, chunk_size, data_disks, sig);
 378                 if(err != 0) {
 379                         if (err != 2)
 380                                 unlock_all_stripes(info, sig);
 381                         goto exitCheck;
 382                 }
 383                 for (i = 0 ; i < raid_disks ; i++) {
 384                         off64_t seek_res = lseek(source[i], offsets[i] + start * chunk_size,
 385                                                    SEEK_SET);
 386                         if (seek_res < 0) {
 387                                 fprintf(stderr, "lseek to source %d failed\n", i);
 388                                 unlock_all_stripes(info, sig);
 389                                 err = -1;
 390                                 goto exitCheck;
 391                         }
 392                         int read_res = read(source[i], stripes[i], chunk_size);
 393                         if (read_res < chunk_size) {
 394                                 fprintf(stderr, "Failed to read complete chunk disk %d, aborting\n", i);
 395                                 unlock_all_stripes(info, sig);
 396                                 err = -1;
 397                                 goto exitCheck;
 398                         }
 399                 }
 400
 401                 diskP = geo_map(-1, start, raid_disks, level, layout);
 402                 block_index_for_slot[-1] = diskP;
 403                 blocks[-1] = stripes[diskP];
 404
 405                 diskQ = geo_map(-2, start, raid_disks, level, layout);
 406                 block_index_for_slot[-2] = diskQ;
 407                 blocks[-2] = stripes[diskQ];
 408
 409                 if (!is_ddf(layout)) {
 410                         /* The syndrome-order of disks starts immediately after 'Q',
 411                          * but skips P */
 412                         diskD = diskQ;
 413                         for (i = 0 ; i < data_disks ; i++) {
 414                                 diskD = diskD + 1;
 415                                 if (diskD >= raid_disks)
 416                                         diskD = 0;
 417                                 if (diskD == diskP)
 418                                         diskD += 1;
 419                                 if (diskD >= raid_disks)
 420                                         diskD = 0;
 421                                 blocks[i] = stripes[diskD];
 422                                 block_index_for_slot[i] = diskD;
 423                         }
 424                 } else {
 425                         /* The syndrome-order exactly follows raid-disk
 426                          * numbers, with ZERO in place of P and Q
 427                          */
 428                         for (i = 0 ; i < raid_disks; i++) {
 429                                 if (i == diskP || i == diskQ) {
 430                                         blocks[i] = zero;
 431                                         block_index_for_slot[i] = -1;
 432                                 } else {
 433                                         blocks[i] = stripes[i];
 434                                         block_index_for_slot[i] = i;
 435                                 }
 436                         }
 437                 }
 438
 439                 qsyndrome(p, q, (uint8_t**)blocks, syndrome_disks, chunk_size);
 440
 441                 raid6_collect(chunk_size, p, q, stripes[diskP], stripes[diskQ], results);
 442                 raid6_stats(disk, results, raid_disks, chunk_size);
 443
 444                 for(j = 0; j < (chunk_size >> CHECK_PAGE_BITS); j++) {
 445                         int role = disk[j];
 446                         if (role >= -2) {
 447                                 int slot = block_index_for_slot[role];
 448                                 if (slot >= 0)
 449                                         printf("Error detected at stripe %llu, page %d: possible failed disk slot %d: %d --> %s\n",
 450                                                start, j, role, slot, name[slot]);
 451                                 else
 452                                         printf("Error detected at stripe %llu, page %d: failed slot %d should be zeros\n",
 453                                                start, j, role);
 454                         } else if(disk[j] == -65535) {
 455                                 printf("Error detected at stripe %llu, page %d: disk slot unknown\n", start, j);
 456                         }
 457                 }
 458
 459                 if(repair == AUTO_REPAIR) {
 460                         err = autorepair(disk, start, chunk_size,
 461                                         name, raid_disks, syndrome_disks, blocks_page,
 462                                         blocks, p, block_index_for_slot,
 463                                         source, offsets);
 464                         if(err != 0) {
 465                                 unlock_all_stripes(info, sig);
 466                                 goto exitCheck;
 467                         }
 468                 }
 469
 470                 if(repair == MANUAL_REPAIR) {
 471                         int failed_slot1 = -1, failed_slot2 = -1;
 472                         for (i = -2; i < syndrome_disks; i++) {
 473                                 if (block_index_for_slot[i] == failed_disk1)
 474                                         failed_slot1 = i;
 475                                 if (block_index_for_slot[i] == failed_disk2)
 476                                         failed_slot2 = i;
 477                         }
 478                         err = manual_repair(chunk_size, syndrome_disks,
 479                                             failed_slot1, failed_slot2,
 480                                             start, block_index_for_slot,
 481                                             name, stripes, blocks, p,
 482                                             source, offsets);
 483                         if(err == -1) {
 484                                 unlock_all_stripes(info, sig);
 485                                 goto exitCheck;
 486                         }
 487                 }
 488
 489                 err = unlock_all_stripes(info, sig);
 490                 if(err != 0) {
 491                         goto exitCheck;
 492                 }
 493
 494                 length--;
 495                 start++;
 496         }
 497
 498 exitCheck:
 499
 500         free(stripe_buf);
 501         free(stripes);
 502         free(blocks-2);
 503         free(blocks_page-2);
 504         free(block_index_for_slot-2);
 505         free(p);
 506         free(q);
 507         free(results);
 508         free(sig);
 509
 510         return err;
 511 }
 512
 513 unsigned long long getnum(char *str, char **err)
 514 {
 515         char *e;
 516         unsigned long long rv = strtoull(str, &e, 10);
 517         if (e==str || *e) {
 518                 *err = str;
 519                 return 0;
 520         }
 521         return rv;
 522 }
 523
 524 int main(int argc, char *argv[])
 525 {
 526         /* md_device start length */
 527         int *fds = NULL;
 528         char *buf = NULL;
 529         char **disk_name = NULL;
 530         unsigned long long *offsets = NULL;
 531         int raid_disks = 0;
 532         int active_disks;
 533         int chunk_size = 0;
 534         int layout = -1;
 535         int level = 6;
 536         enum repair repair = NO_REPAIR;
 537         int failed_disk1 = -1;
 538         int failed_disk2 = -1;
 539         unsigned long long start, length;
 540         int i;
 541         int mdfd;
 542         struct mdinfo *info = NULL, *comp = NULL;
 543         char *err = NULL;
 544         int exit_err = 0;
 545         int close_flag = 0;
 546         char *prg = strrchr(argv[0], '/');
 547
 548         if (prg == NULL)
 549                 prg = argv[0];
 550         else
 551                 prg++;
 552
 553         if (argc < 4) {
 554                 fprintf(stderr, "Usage: %s md_device start_stripe length_stripes [autorepair]\n", prg);
 555                 fprintf(stderr, "   or: %s md_device repair stripe failed_slot_1 failed_slot_2\n", prg);
 556                 exit_err = 1;
 557                 goto exitHere;
 558         }
 559
 560         mdfd = open(argv[1], O_RDONLY);
 561         if(mdfd < 0) {
 562                 perror(argv[1]);
 563                 fprintf(stderr, "%s: cannot open %s\n", prg, argv[1]);
 564                 exit_err = 2;
 565                 goto exitHere;
 566         }
 567
 568         info = sysfs_read(mdfd, NULL,
 569                           GET_LEVEL|
 570                           GET_LAYOUT|
 571                           GET_DISKS|
 572                           GET_STATE |
 573                           GET_COMPONENT|
 574                           GET_CHUNK|
 575                           GET_DEVS|
 576                           GET_OFFSET|
 577                           GET_SIZE);
 578
 579         if(info == NULL) {
 580                 fprintf(stderr, "%s: Error reading sysfs information of %s\n", prg, argv[1]);
 581                 exit_err = 9;
 582                 goto exitHere;
 583         }
 584
 585         if(info->array.level != level) {
 586                 fprintf(stderr, "%s: %s not a RAID-6\n", prg, argv[1]);
 587                 exit_err = 3;
 588                 goto exitHere;
 589         }
 590
 591         if(info->array.failed_disks > 0) {
 592                 fprintf(stderr, "%s: %s degraded array\n", prg, argv[1]);
 593                 exit_err = 8;
 594                 goto exitHere;
 595         }
 596
 597         printf("layout: %d\n", info->array.layout);
 598         printf("disks: %d\n", info->array.raid_disks);
 599         printf("component size: %llu\n", info->component_size * 512);
 600         printf("total stripes: %llu\n", (info->component_size * 512) / info->array.chunk_size);
 601         printf("chunk size: %d\n", info->array.chunk_size);
 602         printf("\n");
 603
 604         comp = info->devs;
 605         for(i = 0, active_disks = 0; active_disks < info->array.raid_disks; i++) {
 606                 printf("disk: %d - offset: %llu - size: %llu - name: %s - slot: %d\n",
 607                         i, comp->data_offset * 512, comp->component_size * 512,
 608                         map_dev(comp->disk.major, comp->disk.minor, 0),
 609                         comp->disk.raid_disk);
 610                 if(comp->disk.raid_disk >= 0)
 611                         active_disks++;
 612                 comp = comp->next;
 613         }
 614         printf("\n");
 615
 616         close(mdfd);
 617
 618         raid_disks = info->array.raid_disks;
 619         chunk_size = info->array.chunk_size;
 620         layout = info->array.layout;
 621         if (strcmp(argv[2], "repair")==0) {
 622                 if (argc < 6) {
 623                         fprintf(stderr, "For repair mode, call %s md_device repair stripe failed_slot_1 failed_slot_2\n", prg);
 624                         exit_err = 1;
 625                         goto exitHere;
 626                 }
 627                 repair = MANUAL_REPAIR;
 628                 start = getnum(argv[3], &err);
 629                 length = 1;
 630                 failed_disk1 = getnum(argv[4], &err);
 631                 failed_disk2 = getnum(argv[5], &err);
 632
 633                 if(failed_disk1 >= info->array.raid_disks) {
 634                         fprintf(stderr, "%s: failed_slot_1 index is higher than number of devices in raid\n", prg);
 635                         exit_err = 4;
 636                         goto exitHere;
 637                 }
 638                 if(failed_disk2 >= info->array.raid_disks) {
 639                         fprintf(stderr, "%s: failed_slot_2 index is higher than number of devices in raid\n", prg);
 640                         exit_err = 4;
 641                         goto exitHere;
 642                 }
 643                 if(failed_disk1 == failed_disk2) {
 644                         fprintf(stderr, "%s: failed_slot_1 and failed_slot_2 are the same\n", prg);
 645                         exit_err = 4;
 646                         goto exitHere;
 647                 }
 648         }
 649         else {
 650                 start = getnum(argv[2], &err);
 651                 length = getnum(argv[3], &err);
 652                 if (argc >= 5 && strcmp(argv[4], "autorepair")==0)
 653                         repair = AUTO_REPAIR;
 654         }
 655
 656         if (err) {
 657                 fprintf(stderr, "%s: Bad number: %s\n", prg, err);
 658                 exit_err = 4;
 659                 goto exitHere;
 660         }
 661
 662         if(start > ((info->component_size * 512) / chunk_size)) {
 663                 start = (info->component_size * 512) / chunk_size;
 664                 fprintf(stderr, "%s: start beyond disks size\n", prg);
 665         }
 666
 667         if((length == 0) ||
 668            ((length + start) > ((info->component_size * 512) / chunk_size))) {
 669                 length = (info->component_size * 512) / chunk_size - start;
 670         }
 671
 672         disk_name = xmalloc(raid_disks * sizeof(*disk_name));
 673         fds = xmalloc(raid_disks * sizeof(*fds));
 674         offsets = xcalloc(raid_disks, sizeof(*offsets));
 675         buf = xmalloc(raid_disks * chunk_size);
 676
 677         for(i=0; i<raid_disks; i++) {
 678                 fds[i] = -1;
 679         }
 680         close_flag = 1;
 681
 682         comp = info->devs;
 683         for (i=0, active_disks=0; active_disks<raid_disks; i++) {
 684                 int disk_slot = comp->disk.raid_disk;
 685                 if(disk_slot >= 0) {
 686                         disk_name[disk_slot] = map_dev(comp->disk.major, comp->disk.minor, 0);
 687                         offsets[disk_slot] = comp->data_offset * 512;
 688                         fds[disk_slot] = open(disk_name[disk_slot], O_RDWR | O_DIRECT);
 689                         if (fds[disk_slot] < 0) {
 690                                 perror(disk_name[disk_slot]);
 691                                 fprintf(stderr,"%s: cannot open %s\n", prg, disk_name[disk_slot]);
 692                                 exit_err = 6;
 693                                 goto exitHere;
 694                         }
 695                         active_disks++;
 696                 }
 697                 comp = comp->next;
 698         }
 699
 700         int rv = check_stripes(info, fds, offsets,
 701                                raid_disks, chunk_size, level, layout,
 702                                start, length, disk_name, repair, failed_disk1, failed_disk2);
 703         if (rv != 0) {
 704                 fprintf(stderr, "%s: check_stripes returned %d\n", prg, rv);
 705                 exit_err = 7;
 706                 goto exitHere;
 707         }
 708
 709 exitHere:
 710
 711         if (close_flag)
 712                 for(i = 0; i < raid_disks; i++)
 713                         close(fds[i]);
 714
 715         free(disk_name);
 716         free(fds);
 717         free(offsets);
 718         free(buf);
 719
 720         exit(exit_err);
 721 }