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 <stdint.h>
  27 #include <signal.h>
  28 #include <sys/mman.h>
  29
  30 #define CHECK_PAGE_BITS (12)
  31 #define CHECK_PAGE_SIZE (1 << CHECK_PAGE_BITS)
  32
  33 enum repair {
  34         NO_REPAIR = 0,
  35         MANUAL_REPAIR,
  36         AUTO_REPAIR
  37 };
  38
  39 int geo_map(int block, unsigned long long stripe, int raid_disks,
  40             int level, int layout);
  41 void qsyndrome(uint8_t *p, uint8_t *q, uint8_t **sources, int disks, int size);
  42 void make_tables(void);
  43 void ensure_zero_has_size(int chunk_size);
  44 void raid6_datap_recov(int disks, size_t bytes, int faila, uint8_t **ptrs);
  45 void raid6_2data_recov(int disks, size_t bytes, int faila, int failb,
  46                        uint8_t **ptrs);
  47 void xor_blocks(char *target, char **sources, int disks, int size);
  48
  49 /* Collect per stripe consistency information */
  50 void raid6_collect(int chunk_size, uint8_t *p, uint8_t *q,
  51                    char *chunkP, char *chunkQ, int *results)
  52 {
  53         int i;
  54         int data_id;
  55         uint8_t Px, Qx;
  56         extern uint8_t raid6_gflog[];
  57
  58         for(i = 0; i < chunk_size; i++) {
  59                 Px = (uint8_t)chunkP[i] ^ (uint8_t)p[i];
  60                 Qx = (uint8_t)chunkQ[i] ^ (uint8_t)q[i];
  61
  62                 if((Px != 0) && (Qx == 0))
  63                         results[i] = -1;
  64
  65                 if((Px == 0) && (Qx != 0))
  66                         results[i] = -2;
  67
  68                 if((Px != 0) && (Qx != 0)) {
  69                         data_id = (raid6_gflog[Qx] - raid6_gflog[Px]);
  70                         if(data_id < 0) data_id += 255;
  71                         results[i] = data_id;
  72                 }
  73
  74                 if((Px == 0) && (Qx == 0))
  75                         results[i] = -255;
  76         }
  77 }
  78
  79 /* Try to find out if a specific disk has problems in a CHECK_PAGE_SIZE page size */
  80 int raid6_stats_blk(int *results, int raid_disks)
  81 {
  82         int i;
  83         int curr_broken_disk = -255;
  84         int prev_broken_disk = -255;
  85         int broken_status = 0;
  86
  87         for(i = 0; i < CHECK_PAGE_SIZE; i++) {
  88
  89                 if(results[i] != -255)
  90                         curr_broken_disk = results[i];
  91
  92                 if(curr_broken_disk >= raid_disks)
  93                         broken_status = 2;
  94
  95                 switch(broken_status) {
  96                 case 0:
  97                         if(curr_broken_disk != -255) {
  98                                 prev_broken_disk = curr_broken_disk;
  99                                 broken_status = 1;
 100                         }
 101                         break;
 102
 103                 case 1:
 104                         if(curr_broken_disk != prev_broken_disk)
 105                                 broken_status = 2;
 106                         break;
 107
 108                 case 2:
 109                 default:
 110                         curr_broken_disk = prev_broken_disk = -65535;
 111                         break;
 112                 }
 113         }
 114
 115         return curr_broken_disk;
 116 }
 117
 118 /* Collect disks status for a strip in CHECK_PAGE_SIZE page size blocks */
 119 void raid6_stats(int *disk, int *results, int raid_disks, int chunk_size)
 120 {
 121         int i, j;
 122
 123         for(i = 0, j = 0; i < chunk_size; i += CHECK_PAGE_SIZE, j++) {
 124                 disk[j] = raid6_stats_blk(&results[i], raid_disks);
 125         }
 126 }
 127
 128 int lock_stripe(struct mdinfo *info, unsigned long long start,
 129                 int chunk_size, int data_disks, sighandler_t *sig) {
 130         int rv;
 131         if(mlockall(MCL_CURRENT | MCL_FUTURE) != 0) {
 132                 return 2;
 133         }
 134
 135         sig[0] = signal(SIGTERM, SIG_IGN);
 136         sig[1] = signal(SIGINT, SIG_IGN);
 137         sig[2] = signal(SIGQUIT, SIG_IGN);
 138
 139         rv = sysfs_set_num(info, NULL, "suspend_lo", start * chunk_size * data_disks);
 140         rv |= sysfs_set_num(info, NULL, "suspend_hi", (start + 1) * chunk_size * data_disks);
 141         return rv * 256;
 142 }
 143
 144 int unlock_all_stripes(struct mdinfo *info, sighandler_t *sig) {
 145         int rv;
 146         rv = sysfs_set_num(info, NULL, "suspend_lo", 0x7FFFFFFFFFFFFFFFULL);
 147         rv |= sysfs_set_num(info, NULL, "suspend_hi", 0);
 148         rv |= sysfs_set_num(info, NULL, "suspend_lo", 0);
 149
 150         signal(SIGQUIT, sig[2]);
 151         signal(SIGINT, sig[1]);
 152         signal(SIGTERM, sig[0]);
 153
 154         if(munlockall() != 0)
 155                 return 3;
 156         return rv * 256;
 157 }
 158
 159 /* Autorepair */
 160 int autorepair(int *disk, int diskP, int diskQ, unsigned long long start, int chunk_size,
 161                 char *name[], int raid_disks, int data_disks, char **blocks_page,
 162                 char **blocks, uint8_t *p, char **stripes, int *block_index_for_slot,
 163                 int *source, unsigned long long *offsets)
 164 {
 165         int i, j;
 166         int pages_to_write_count = 0;
 167         int page_to_write[chunk_size >> CHECK_PAGE_BITS];
 168         for(j = 0; j < (chunk_size >> CHECK_PAGE_BITS); j++) {
 169                 if (disk[j] >= 0) {
 170                         printf("Auto-repairing slot %d (%s)\n", disk[j], name[disk[j]]);
 171                         pages_to_write_count++;
 172                         page_to_write[j] = 1;
 173                         for(i = 0; i < raid_disks; i++) {
 174                                 blocks_page[i] = blocks[i] + j * CHECK_PAGE_SIZE;
 175                         }
 176                         if (disk[j] == diskQ) {
 177                                 qsyndrome(p, (uint8_t*)stripes[diskQ] + j * CHECK_PAGE_SIZE, (uint8_t**)blocks_page, data_disks, CHECK_PAGE_SIZE);
 178                         }
 179                         else {
 180                                 char *all_but_failed_blocks[data_disks];
 181                                 int failed_block_index = block_index_for_slot[disk[j]];
 182                                 for(i = 0; i < data_disks; i++) {
 183                                         if (failed_block_index == i) {
 184                                                 all_but_failed_blocks[i] = stripes[diskP] + j * CHECK_PAGE_SIZE;
 185                                         }
 186                                         else {
 187                                                 all_but_failed_blocks[i] = blocks_page[i];
 188                                         }
 189                                 }
 190                                 xor_blocks(stripes[disk[j]] + j * CHECK_PAGE_SIZE,
 191                                 all_but_failed_blocks, data_disks, CHECK_PAGE_SIZE);
 192                         }
 193                 }
 194                 else {
 195                         page_to_write[j] = 0;
 196                 }
 197         }
 198
 199         if(pages_to_write_count > 0) {
 200                 int write_res = 0;
 201                 for(j = 0; j < (chunk_size >> CHECK_PAGE_BITS); j++) {
 202                         if(page_to_write[j] == 1) {
 203                                 lseek64(source[disk[j]], offsets[disk[j]] + start * chunk_size + j * CHECK_PAGE_SIZE, SEEK_SET);
 204                                 write_res += write(source[disk[j]], stripes[disk[j]] + j * CHECK_PAGE_SIZE, CHECK_PAGE_SIZE);
 205                         }
 206                 }
 207
 208                 if (write_res != (CHECK_PAGE_SIZE * pages_to_write_count)) {
 209                         fprintf(stderr, "Failed to write a full chunk.\n");
 210                         return -1;
 211                 }
 212         }
 213
 214         return 0;
 215 }
 216
 217 /* Manual repair */
 218 int manual_repair(int diskP, int diskQ, int chunk_size, int raid_disks, int data_disks,
 219                   int failed_disk1, int failed_disk2, unsigned long long start, int *block_index_for_slot,
 220                   char *name[], char **stripes, char **blocks, uint8_t *p, struct mdinfo *info, sighandler_t *sig,
 221                   int *source, unsigned long long *offsets)
 222 {
 223         int err = 0;
 224         int i;
 225         printf("Repairing stripe %llu\n", start);
 226         printf("Assuming slots %d (%s) and %d (%s) are incorrect\n",
 227                failed_disk1, name[failed_disk1],
 228                failed_disk2, name[failed_disk2]);
 229
 230         if (failed_disk1 == diskQ || failed_disk2 == diskQ) {
 231                 char *all_but_failed_blocks[data_disks];
 232                 int failed_data_or_p;
 233                 int failed_block_index;
 234
 235                 if (failed_disk1 == diskQ) {
 236                         failed_data_or_p = failed_disk2;
 237                 }
 238                 else {
 239                         failed_data_or_p = failed_disk1;
 240                 }
 241                 printf("Repairing D/P(%d) and Q\n", failed_data_or_p);
 242                 failed_block_index = block_index_for_slot[failed_data_or_p];
 243                 for (i = 0; i < data_disks; i++) {
 244                         if (failed_block_index == i) {
 245                                 all_but_failed_blocks[i] = stripes[diskP];
 246                         }
 247                         else {
 248                                 all_but_failed_blocks[i] = blocks[i];
 249                         }
 250                 }
 251                 xor_blocks(stripes[failed_data_or_p],
 252                            all_but_failed_blocks, data_disks, chunk_size);
 253                 qsyndrome(p, (uint8_t*)stripes[diskQ], (uint8_t**)blocks, data_disks, chunk_size);
 254         }
 255         else {
 256                 ensure_zero_has_size(chunk_size);
 257                 if (failed_disk1 == diskP || failed_disk2 == diskP) {
 258                         int failed_data, failed_block_index;
 259                         if (failed_disk1 == diskP) {
 260                                 failed_data = failed_disk2;
 261                         }
 262                         else {
 263                                 failed_data = failed_disk1;
 264                         }
 265                         failed_block_index = block_index_for_slot[failed_data];
 266                         printf("Repairing D(%d) and P\n", failed_data);
 267                         raid6_datap_recov(raid_disks, chunk_size, failed_block_index, (uint8_t**)blocks);
 268                 }
 269                 else {
 270                         printf("Repairing D and D\n");
 271                         int failed_block_index1 = block_index_for_slot[failed_disk1];
 272                         int failed_block_index2 = block_index_for_slot[failed_disk2];
 273                         if (failed_block_index1 > failed_block_index2) {
 274                                 int t = failed_block_index1;
 275                                 failed_block_index1 = failed_block_index2;
 276                                 failed_block_index2 = t;
 277                         }
 278                         raid6_2data_recov(raid_disks, chunk_size, failed_block_index1, failed_block_index2, (uint8_t**)blocks);
 279                 }
 280         }
 281
 282         err = lock_stripe(info, start, chunk_size, data_disks, sig);
 283         if(err != 0) {
 284                 if (err != 2) {
 285                         return -1;
 286                 }
 287                 return -2;;
 288         }
 289
 290         int write_res1, write_res2;
 291         off64_t seek_res;
 292
 293         seek_res = lseek64(source[failed_disk1],
 294                            offsets[failed_disk1] + start * chunk_size, SEEK_SET);
 295         if (seek_res < 0) {
 296                 fprintf(stderr, "lseek failed for failed_disk1\n");
 297                 return -1;
 298         }
 299         write_res1 = write(source[failed_disk1], stripes[failed_disk1], chunk_size);
 300
 301         seek_res = lseek64(source[failed_disk2],
 302                            offsets[failed_disk2] + start * chunk_size, SEEK_SET);
 303         if (seek_res < 0) {
 304                 fprintf(stderr, "lseek failed for failed_disk1\n");
 305                 return -1;
 306         }
 307         write_res2 = write(source[failed_disk2], stripes[failed_disk2], chunk_size);
 308
 309         err = unlock_all_stripes(info, sig);
 310         if(err != 0) {
 311                 return -2;
 312         }
 313
 314         if (write_res1 != chunk_size || write_res2 != chunk_size) {
 315                 fprintf(stderr, "Failed to write a complete chunk.\n");
 316                 return -2;
 317         }
 318
 319         return 0;
 320 }
 321
 322 int check_stripes(struct mdinfo *info, int *source, unsigned long long *offsets,
 323                   int raid_disks, int chunk_size, int level, int layout,
 324                   unsigned long long start, unsigned long long length, char *name[],
 325                   enum repair repair, int failed_disk1, int failed_disk2)
 326 {
 327         /* read the data and p and q blocks, and check we got them right */
 328         char *stripe_buf = xmalloc(raid_disks * chunk_size);
 329         char **stripes = xmalloc(raid_disks * sizeof(char*));
 330         char **blocks = xmalloc(raid_disks * sizeof(char*));
 331         char **blocks_page = xmalloc(raid_disks * sizeof(char*));
 332         int *block_index_for_slot = xmalloc(raid_disks * sizeof(int));
 333         uint8_t *p = xmalloc(chunk_size);
 334         uint8_t *q = xmalloc(chunk_size);
 335         int *results = xmalloc(chunk_size * sizeof(int));
 336         sighandler_t *sig = xmalloc(3 * sizeof(sighandler_t));
 337
 338         int i, j;
 339         int diskP, diskQ;
 340         int data_disks = raid_disks - 2;
 341         int err = 0;
 342
 343         extern int tables_ready;
 344
 345         if (!tables_ready)
 346                 make_tables();
 347
 348         for ( i = 0 ; i < raid_disks ; i++)
 349                 stripes[i] = stripe_buf + i * chunk_size;
 350
 351         while (length > 0) {
 352                 int disk[chunk_size >> CHECK_PAGE_BITS];
 353
 354                 err = lock_stripe(info, start, chunk_size, data_disks, sig);
 355                 if(err != 0) {
 356                         if (err != 2)
 357                                 unlock_all_stripes(info, sig);
 358                         goto exitCheck;
 359                 }
 360                 for (i = 0 ; i < raid_disks ; i++) {
 361                         off64_t seek_res = lseek64(source[i], offsets[i] + start * chunk_size,
 362                                                    SEEK_SET);
 363                         if (seek_res < 0) {
 364                                 fprintf(stderr, "lseek to source %d failed\n", i);
 365                                 unlock_all_stripes(info, sig);
 366                                 err = -1;
 367                                 goto exitCheck;
 368                         }
 369                         int read_res = read(source[i], stripes[i], chunk_size);
 370                         if (read_res < chunk_size) {
 371                                 fprintf(stderr, "Failed to read complete chunk disk %d, aborting\n", i);
 372                                 unlock_all_stripes(info, sig);
 373                                 err = -1;
 374                                 goto exitCheck;
 375                         }
 376                 }
 377
 378                 for (i = 0 ; i < data_disks ; i++) {
 379                         int disk = geo_map(i, start, raid_disks, level, layout);
 380                         blocks[i] = stripes[disk];
 381                         block_index_for_slot[disk] = i;
 382                 }
 383
 384                 qsyndrome(p, q, (uint8_t**)blocks, data_disks, chunk_size);
 385                 diskP = geo_map(-1, start, raid_disks, level, layout);
 386                 diskQ = geo_map(-2, start, raid_disks, level, layout);
 387                 blocks[data_disks] = stripes[diskP];
 388                 block_index_for_slot[diskP] = data_disks;
 389                 blocks[data_disks+1] = stripes[diskQ];
 390                 block_index_for_slot[diskQ] = data_disks+1;
 391
 392                 raid6_collect(chunk_size, p, q, stripes[diskP], stripes[diskQ], results);
 393                 raid6_stats(disk, results, raid_disks, chunk_size);
 394
 395                 for(j = 0; j < (chunk_size >> CHECK_PAGE_BITS); j++) {
 396                         if(disk[j] >= -2) {
 397                                 disk[j] = geo_map(disk[j], start, raid_disks, level, layout);
 398                         }
 399                         if(disk[j] >= 0) {
 400                                 printf("Error detected at stripe %llu, page %d: possible failed disk slot: %d --> %s\n",
 401                                         start, j, disk[j], name[disk[j]]);
 402                         }
 403                         if(disk[j] == -65535) {
 404                                 printf("Error detected at stripe %llu, page %d: disk slot unknown\n", start, j);
 405                         }
 406                 }
 407
 408                 if(repair == AUTO_REPAIR) {
 409                         err = autorepair(disk, diskP, diskQ, start, chunk_size,
 410                                         name, raid_disks, data_disks, blocks_page,
 411                                         blocks, p, stripes, block_index_for_slot,
 412                                         source, offsets);
 413                         if(err != 0) {
 414                                 unlock_all_stripes(info, sig);
 415                                 goto exitCheck;
 416                         }
 417                 }
 418
 419                 err = unlock_all_stripes(info, sig);
 420                 if(err != 0) {
 421                         goto exitCheck;
 422                 }
 423
 424                 if(repair == MANUAL_REPAIR) {
 425                         err = manual_repair(diskP, diskQ, chunk_size, raid_disks, data_disks,
 426                                         failed_disk1, failed_disk2, start, block_index_for_slot,
 427                                         name, stripes, blocks, p, info, sig,
 428                                         source, offsets);
 429                         if(err == -1) {
 430                                 unlock_all_stripes(info, sig);
 431                                 goto exitCheck;
 432                         }
 433                 }
 434
 435                 length--;
 436                 start++;
 437         }
 438
 439 exitCheck:
 440
 441         free(stripe_buf);
 442         free(stripes);
 443         free(blocks);
 444         free(blocks_page);
 445         free(block_index_for_slot);
 446         free(p);
 447         free(q);
 448         free(results);
 449         free(sig);
 450
 451         return err;
 452 }
 453
 454 unsigned long long getnum(char *str, char **err)
 455 {
 456         char *e;
 457         unsigned long long rv = strtoull(str, &e, 10);
 458         if (e==str || *e) {
 459                 *err = str;
 460                 return 0;
 461         }
 462         return rv;
 463 }
 464
 465 int main(int argc, char *argv[])
 466 {
 467         /* md_device start length */
 468         int *fds = NULL;
 469         char *buf = NULL;
 470         char **disk_name = NULL;
 471         unsigned long long *offsets = NULL;
 472         int raid_disks = 0;
 473         int active_disks;
 474         int chunk_size = 0;
 475         int layout = -1;
 476         int level = 6;
 477         enum repair repair = NO_REPAIR;
 478         int failed_disk1 = -1;
 479         int failed_disk2 = -1;
 480         unsigned long long start, length;
 481         int i;
 482         int mdfd;
 483         struct mdinfo *info = NULL, *comp = NULL;
 484         char *err = NULL;
 485         int exit_err = 0;
 486         int close_flag = 0;
 487         char *prg = strrchr(argv[0], '/');
 488
 489         if (prg == NULL)
 490                 prg = argv[0];
 491         else
 492                 prg++;
 493
 494         if (argc < 4) {
 495                 fprintf(stderr, "Usage: %s md_device start_stripe length_stripes [autorepair]\n", prg);
 496                 fprintf(stderr, "   or: %s md_device repair stripe failed_slot_1 failed_slot_2\n", prg);
 497                 exit_err = 1;
 498                 goto exitHere;
 499         }
 500
 501         mdfd = open(argv[1], O_RDONLY);
 502         if(mdfd < 0) {
 503                 perror(argv[1]);
 504                 fprintf(stderr, "%s: cannot open %s\n", prg, argv[1]);
 505                 exit_err = 2;
 506                 goto exitHere;
 507         }
 508
 509         info = sysfs_read(mdfd, NULL,
 510                           GET_LEVEL|
 511                           GET_LAYOUT|
 512                           GET_DISKS|
 513                           GET_DEGRADED |
 514                           GET_COMPONENT|
 515                           GET_CHUNK|
 516                           GET_DEVS|
 517                           GET_OFFSET|
 518                           GET_SIZE);
 519
 520         if(info == NULL) {
 521                 fprintf(stderr, "%s: Error reading sysfs information of %s\n", prg, argv[1]);
 522                 exit_err = 9;
 523                 goto exitHere;
 524         }
 525
 526         if(info->array.level != level) {
 527                 fprintf(stderr, "%s: %s not a RAID-6\n", prg, argv[1]);
 528                 exit_err = 3;
 529                 goto exitHere;
 530         }
 531
 532         if(info->array.failed_disks > 0) {
 533                 fprintf(stderr, "%s: %s degraded array\n", prg, argv[1]);
 534                 exit_err = 8;
 535                 goto exitHere;
 536         }
 537
 538         printf("layout: %d\n", info->array.layout);
 539         printf("disks: %d\n", info->array.raid_disks);
 540         printf("component size: %llu\n", info->component_size * 512);
 541         printf("total stripes: %llu\n", (info->component_size * 512) / info->array.chunk_size);
 542         printf("chunk size: %d\n", info->array.chunk_size);
 543         printf("\n");
 544
 545         comp = info->devs;
 546         for(i = 0, active_disks = 0; active_disks < info->array.raid_disks; i++) {
 547                 printf("disk: %d - offset: %llu - size: %llu - name: %s - slot: %d\n",
 548                         i, comp->data_offset * 512, comp->component_size * 512,
 549                         map_dev(comp->disk.major, comp->disk.minor, 0),
 550                         comp->disk.raid_disk);
 551                 if(comp->disk.raid_disk >= 0)
 552                         active_disks++;
 553                 comp = comp->next;
 554         }
 555         printf("\n");
 556
 557         close(mdfd);
 558
 559         raid_disks = info->array.raid_disks;
 560         chunk_size = info->array.chunk_size;
 561         layout = info->array.layout;
 562         if (strcmp(argv[2], "repair")==0) {
 563                 if (argc < 6) {
 564                         fprintf(stderr, "For repair mode, call %s md_device repair stripe failed_slot_1 failed_slot_2\n", prg);
 565                         exit_err = 1;
 566                         goto exitHere;
 567                 }
 568                 repair = MANUAL_REPAIR;
 569                 start = getnum(argv[3], &err);
 570                 length = 1;
 571                 failed_disk1 = getnum(argv[4], &err);
 572                 failed_disk2 = getnum(argv[5], &err);
 573
 574                 if(failed_disk1 >= info->array.raid_disks) {
 575                         fprintf(stderr, "%s: failed_slot_1 index is higher than number of devices in raid\n", prg);
 576                         exit_err = 4;
 577                         goto exitHere;
 578                 }
 579                 if(failed_disk2 >= info->array.raid_disks) {
 580                         fprintf(stderr, "%s: failed_slot_2 index is higher than number of devices in raid\n", prg);
 581                         exit_err = 4;
 582                         goto exitHere;
 583                 }
 584                 if(failed_disk1 == failed_disk2) {
 585                         fprintf(stderr, "%s: failed_slot_1 and failed_slot_2 are the same\n", prg);
 586                         exit_err = 4;
 587                         goto exitHere;
 588                 }
 589         }
 590         else {
 591                 start = getnum(argv[2], &err);
 592                 length = getnum(argv[3], &err);
 593                 if (argc >= 5 && strcmp(argv[4], "autorepair")==0)
 594                         repair = AUTO_REPAIR;
 595         }
 596
 597         if (err) {
 598                 fprintf(stderr, "%s: Bad number: %s\n", prg, err);
 599                 exit_err = 4;
 600                 goto exitHere;
 601         }
 602
 603         if(start > ((info->component_size * 512) / chunk_size)) {
 604                 start = (info->component_size * 512) / chunk_size;
 605                 fprintf(stderr, "%s: start beyond disks size\n", prg);
 606         }
 607
 608         if((length == 0) ||
 609            ((length + start) > ((info->component_size * 512) / chunk_size))) {
 610                 length = (info->component_size * 512) / chunk_size - start;
 611         }
 612
 613         disk_name = xmalloc(raid_disks * sizeof(*disk_name));
 614         fds = xmalloc(raid_disks * sizeof(*fds));
 615         offsets = xcalloc(raid_disks, sizeof(*offsets));
 616         buf = xmalloc(raid_disks * chunk_size);
 617
 618         for(i=0; i<raid_disks; i++) {
 619                 fds[i] = -1;
 620         }
 621         close_flag = 1;
 622
 623         comp = info->devs;
 624         for (i=0, active_disks=0; active_disks<raid_disks; i++) {
 625                 int disk_slot = comp->disk.raid_disk;
 626                 if(disk_slot >= 0) {
 627                         disk_name[disk_slot] = map_dev(comp->disk.major, comp->disk.minor, 0);
 628                         offsets[disk_slot] = comp->data_offset * 512;
 629                         fds[disk_slot] = open(disk_name[disk_slot], O_RDWR | O_SYNC);
 630                         if (fds[disk_slot] < 0) {
 631                                 perror(disk_name[disk_slot]);
 632                                 fprintf(stderr,"%s: cannot open %s\n", prg, disk_name[disk_slot]);
 633                                 exit_err = 6;
 634                                 goto exitHere;
 635                         }
 636                         active_disks++;
 637                 }
 638                 comp = comp->next;
 639         }
 640
 641         int rv = check_stripes(info, fds, offsets,
 642                                raid_disks, chunk_size, level, layout,
 643                                start, length, disk_name, repair, failed_disk1, failed_disk2);
 644         if (rv != 0) {
 645                 fprintf(stderr, "%s: check_stripes returned %d\n", prg, rv);
 646                 exit_err = 7;
 647                 goto exitHere;
 648         }
 649
 650 exitHere:
 651
 652         if (close_flag)
 653                 for(i = 0; i < raid_disks; i++)
 654                         close(fds[i]);
 655
 656         free(disk_name);
 657         free(fds);
 658         free(offsets);
 659         free(buf);
 660
 661         exit(exit_err);
 662 }