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 int check_stripes(struct mdinfo *info, int *source, unsigned long long *offsets,
 160                   int raid_disks, int chunk_size, int level, int layout,
 161                   unsigned long long start, unsigned long long length, char *name[],
 162                   enum repair repair, int failed_disk1, int failed_disk2)
 163 {
 164         /* read the data and p and q blocks, and check we got them right */
 165         char *stripe_buf = xmalloc(raid_disks * chunk_size);
 166         char **stripes = xmalloc(raid_disks * sizeof(char*));
 167         char **blocks = xmalloc(raid_disks * sizeof(char*));
 168         char **blocks_page = xmalloc(raid_disks * sizeof(char*));
 169         int *block_index_for_slot = xmalloc(raid_disks * sizeof(int));
 170         uint8_t *p = xmalloc(chunk_size);
 171         uint8_t *q = xmalloc(chunk_size);
 172         int *results = xmalloc(chunk_size * sizeof(int));
 173         sighandler_t *sig = xmalloc(3 * sizeof(sighandler_t));
 174
 175         int i, j;
 176         int diskP, diskQ;
 177         int data_disks = raid_disks - 2;
 178         int err = 0;
 179
 180         extern int tables_ready;
 181
 182         if (!tables_ready)
 183                 make_tables();
 184
 185         for ( i = 0 ; i < raid_disks ; i++)
 186                 stripes[i] = stripe_buf + i * chunk_size;
 187
 188         while (length > 0) {
 189                 int disk[chunk_size >> CHECK_PAGE_BITS];
 190
 191                 err = lock_stripe(info, start, chunk_size, data_disks, sig);
 192                 if(err != 0) {
 193                         if (err != 2)
 194                                 unlock_all_stripes(info, sig);
 195                         goto exitCheck;
 196                 }
 197                 for (i = 0 ; i < raid_disks ; i++) {
 198                         off64_t seek_res = lseek64(source[i], offsets[i] + start * chunk_size,
 199                                                    SEEK_SET);
 200                         if (seek_res < 0) {
 201                                 fprintf(stderr, "lseek to source %d failed\n", i);
 202                                 unlock_all_stripes(info, sig);
 203                                 err = -1;
 204                                 goto exitCheck;
 205                         }
 206                         int read_res = read(source[i], stripes[i], chunk_size);
 207                         if (read_res < chunk_size) {
 208                                 fprintf(stderr, "Failed to read complete chunk disk %d, aborting\n", i);
 209                                 unlock_all_stripes(info, sig);
 210                                 err = -1;
 211                                 goto exitCheck;
 212                         }
 213                 }
 214                 err = unlock_all_stripes(info, sig);
 215                 if(err != 0)
 216                         goto exitCheck;
 217
 218                 for (i = 0 ; i < data_disks ; i++) {
 219                         int disk = geo_map(i, start, raid_disks, level, layout);
 220                         blocks[i] = stripes[disk];
 221                         block_index_for_slot[disk] = i;
 222                 }
 223
 224                 qsyndrome(p, q, (uint8_t**)blocks, data_disks, chunk_size);
 225                 diskP = geo_map(-1, start, raid_disks, level, layout);
 226                 diskQ = geo_map(-2, start, raid_disks, level, layout);
 227                 blocks[data_disks] = stripes[diskP];
 228                 block_index_for_slot[diskP] = data_disks;
 229                 blocks[data_disks+1] = stripes[diskQ];
 230                 block_index_for_slot[diskQ] = data_disks+1;
 231 /* Do we really need the code below? */
 232 #if 0
 233                 if (memcmp(p, stripes[diskP], chunk_size) != 0) {
 234                         printf("P(%d) wrong at %llu\n", diskP, start);
 235                 }
 236                 if (memcmp(q, stripes[diskQ], chunk_size) != 0) {
 237                         printf("Q(%d) wrong at %llu\n", diskQ, start);
 238                 }
 239 #endif
 240                 raid6_collect(chunk_size, p, q, stripes[diskP], stripes[diskQ], results);
 241                 raid6_stats(disk, results, raid_disks, chunk_size);
 242
 243                 for(j = 0; j < (chunk_size >> CHECK_PAGE_BITS); j++) {
 244                         if(disk[j] >= -2) {
 245                                 disk[j] = geo_map(disk[j], start, raid_disks, level, layout);
 246                         }
 247                         if(disk[j] >= 0) {
 248                                 printf("Error detected at %llu, page %d: possible failed disk slot: %d --> %s\n",
 249                                         start, j, disk[j], name[disk[j]]);
 250                         }
 251                         if(disk[j] == -65535) {
 252                                 printf("Error detected at %llu, page %d: disk slot unknown\n", start, j);
 253                         }
 254                 }
 255
 256                 if(repair == MANUAL_REPAIR) {
 257                         printf("Repairing stripe %llu\n", start);
 258                         printf("Assuming slots %d (%s) and %d (%s) are incorrect\n",
 259                                failed_disk1, name[failed_disk1],
 260                                failed_disk2, name[failed_disk2]);
 261
 262                         if (failed_disk1 == diskQ || failed_disk2 == diskQ) {
 263                                 char *all_but_failed_blocks[data_disks];
 264                                 int failed_data_or_p;
 265                                 int failed_block_index;
 266
 267                                 if (failed_disk1 == diskQ)
 268                                         failed_data_or_p = failed_disk2;
 269                                 else
 270                                         failed_data_or_p = failed_disk1;
 271                                 printf("Repairing D/P(%d) and Q\n", failed_data_or_p);
 272                                 failed_block_index = block_index_for_slot[failed_data_or_p];
 273                                 for (i=0; i < data_disks; i++)
 274                                         if (failed_block_index == i)
 275                                                 all_but_failed_blocks[i] = stripes[diskP];
 276                                         else
 277                                                 all_but_failed_blocks[i] = blocks[i];
 278                                 xor_blocks(stripes[failed_data_or_p],
 279                                         all_but_failed_blocks, data_disks, chunk_size);
 280                                 qsyndrome(p, (uint8_t*)stripes[diskQ], (uint8_t**)blocks, data_disks, chunk_size);
 281                         } else {
 282                                 ensure_zero_has_size(chunk_size);
 283                                 if (failed_disk1 == diskP || failed_disk2 == diskP) {
 284                                         int failed_data, failed_block_index;
 285                                         if (failed_disk1 == diskP)
 286                                                 failed_data = failed_disk2;
 287                                         else
 288                                                 failed_data = failed_disk1;
 289                                         failed_block_index = block_index_for_slot[failed_data];
 290                                         printf("Repairing D(%d) and P\n", failed_data);
 291                                         raid6_datap_recov(raid_disks, chunk_size, failed_block_index, (uint8_t**)blocks);
 292                                 } else {
 293                                         printf("Repairing D and D\n");
 294                                         int failed_block_index1 = block_index_for_slot[failed_disk1];
 295                                         int failed_block_index2 = block_index_for_slot[failed_disk2];
 296                                         if (failed_block_index1 > failed_block_index2) {
 297                                                 int t = failed_block_index1;
 298                                                 failed_block_index1 = failed_block_index2;
 299                                                 failed_block_index2 = t;
 300                                         }
 301                                         raid6_2data_recov(raid_disks, chunk_size, failed_block_index1, failed_block_index2, (uint8_t**)blocks);
 302                                 }
 303                         }
 304
 305                         err = lock_stripe(info, start, chunk_size, data_disks, sig);
 306                         if(err != 0) {
 307                                 if (err != 2)
 308                                         unlock_all_stripes(info, sig);
 309                                 goto exitCheck;
 310                         }
 311
 312                         int write_res1, write_res2;
 313                         off64_t seek_res;
 314
 315                         seek_res = lseek64(source[failed_disk1],
 316                                            offsets[failed_disk1] + start * chunk_size, SEEK_SET);
 317                         if (seek_res < 0) {
 318                                 fprintf(stderr, "lseek failed for failed_disk1\n");
 319                                 unlock_all_stripes(info, sig);
 320                                 err = -1;
 321                                 goto exitCheck;
 322                         }
 323                         write_res1 = write(source[failed_disk1], stripes[failed_disk1], chunk_size);
 324
 325                         seek_res = lseek64(source[failed_disk2],
 326                                            offsets[failed_disk2] + start * chunk_size, SEEK_SET);
 327                         if (seek_res < 0) {
 328                                 fprintf(stderr, "lseek failed for failed_disk1\n");
 329                                 unlock_all_stripes(info, sig);
 330                                 err = -1;
 331                                 goto exitCheck;
 332                         }
 333                         write_res2 = write(source[failed_disk2], stripes[failed_disk2], chunk_size);
 334
 335                         err = unlock_all_stripes(info, sig);
 336                         if(err != 0)
 337                                 goto exitCheck;
 338
 339                         if (write_res1 != chunk_size || write_res2 != chunk_size) {
 340                                 fprintf(stderr, "Failed to write a complete chunk.\n");
 341                                 goto exitCheck;
 342                         }
 343
 344                 }
 345
 346                 int pages_to_write_count = 0;
 347                 int page_to_write[chunk_size >> CHECK_PAGE_BITS];
 348                 for(j = 0; j < (chunk_size >> CHECK_PAGE_BITS); j++) {
 349                         if (disk[j] >= 0 && repair == AUTO_REPAIR) {
 350                                 printf("Auto-repairing slot %d (%s)\n", disk[j], name[disk[j]]);
 351                                 pages_to_write_count++;
 352                                 page_to_write[j] = 1;
 353                                 for(i = 0; i < raid_disks; i++) {
 354                                         blocks_page[i] = blocks[i] + j * CHECK_PAGE_SIZE;
 355                                 }
 356                                 if (disk[j] == diskQ) {
 357                                         qsyndrome(p, (uint8_t*)stripes[diskQ], (uint8_t**)blocks_page, data_disks, CHECK_PAGE_SIZE);
 358                                 } else {
 359                                         char *all_but_failed_blocks[data_disks];
 360                                         int failed_block_index = block_index_for_slot[disk[j]];
 361                                         for (i=0; i < data_disks; i++)
 362                                                 if (failed_block_index == i)
 363                                                         all_but_failed_blocks[i] = stripes[diskP] + j * CHECK_PAGE_SIZE;
 364                                                 else
 365                                                         all_but_failed_blocks[i] = blocks_page[i];
 366                                         xor_blocks(stripes[disk[j]] + j * CHECK_PAGE_SIZE,
 367                                         all_but_failed_blocks, data_disks, CHECK_PAGE_SIZE);
 368                                 }
 369                         } else {
 370                                 page_to_write[j] = 0;
 371                         }
 372                 }
 373
 374                 if(pages_to_write_count > 0) {
 375
 376                         err = lock_stripe(info, start, chunk_size, data_disks, sig);
 377                         if(err != 0) {
 378                                 if (err != 2)
 379                                         unlock_all_stripes(info, sig);
 380                                 goto exitCheck;
 381                         }
 382
 383                         int write_res = 0;
 384                         for(j = 0; j < (chunk_size >> CHECK_PAGE_BITS); j++) {
 385                                 if(page_to_write[j] == 1) {
 386                                         lseek64(source[disk[j]], offsets[disk[j]] + start * chunk_size + j * CHECK_PAGE_SIZE, 0);
 387                                         write_res += write(source[disk[j]], stripes[disk[j]] + j * CHECK_PAGE_SIZE, CHECK_PAGE_SIZE);
 388                                 }
 389                         }
 390
 391                         err = unlock_all_stripes(info, sig);
 392                         if (err != 0 || write_res != (CHECK_PAGE_SIZE * pages_to_write_count))
 393                                 goto exitCheck;
 394
 395                         if (write_res != (CHECK_PAGE_SIZE * pages_to_write_count)) {
 396                                 fprintf(stderr, "Failed to write a full chunk.\n");
 397                                 goto exitCheck;
 398                         }
 399                 }
 400
 401                 length--;
 402                 start++;
 403         }
 404
 405 exitCheck:
 406
 407         free(stripe_buf);
 408         free(stripes);
 409         free(blocks);
 410         free(blocks_page);
 411         free(block_index_for_slot);
 412         free(p);
 413         free(q);
 414         free(results);
 415         free(sig);
 416
 417         return err;
 418 }
 419
 420 unsigned long long getnum(char *str, char **err)
 421 {
 422         char *e;
 423         unsigned long long rv = strtoull(str, &e, 10);
 424         if (e==str || *e) {
 425                 *err = str;
 426                 return 0;
 427         }
 428         return rv;
 429 }
 430
 431 int main(int argc, char *argv[])
 432 {
 433         /* md_device start length */
 434         int *fds = NULL;
 435         char *buf = NULL;
 436         char **disk_name = NULL;
 437         unsigned long long *offsets = NULL;
 438         int raid_disks = 0;
 439         int active_disks;
 440         int chunk_size = 0;
 441         int layout = -1;
 442         int level = 6;
 443         enum repair repair = NO_REPAIR;
 444         int failed_disk1 = -1;
 445         int failed_disk2 = -1;
 446         unsigned long long start, length;
 447         int i;
 448         int mdfd;
 449         struct mdinfo *info = NULL, *comp = NULL;
 450         char *err = NULL;
 451         int exit_err = 0;
 452         int close_flag = 0;
 453         char *prg = strrchr(argv[0], '/');
 454
 455         if (prg == NULL)
 456                 prg = argv[0];
 457         else
 458                 prg++;
 459
 460         if (argc < 4) {
 461                 fprintf(stderr, "Usage: %s md_device start_stripe length_stripes [autorepair]\n", prg);
 462                 fprintf(stderr, "   or: %s md_device repair stripe failed_slot_1 failed_slot_2\n", prg);
 463                 exit_err = 1;
 464                 goto exitHere;
 465         }
 466
 467         mdfd = open(argv[1], O_RDONLY);
 468         if(mdfd < 0) {
 469                 perror(argv[1]);
 470                 fprintf(stderr, "%s: cannot open %s\n", prg, argv[1]);
 471                 exit_err = 2;
 472                 goto exitHere;
 473         }
 474
 475         info = sysfs_read(mdfd, NULL,
 476                           GET_LEVEL|
 477                           GET_LAYOUT|
 478                           GET_DISKS|
 479                           GET_DEGRADED |
 480                           GET_COMPONENT|
 481                           GET_CHUNK|
 482                           GET_DEVS|
 483                           GET_OFFSET|
 484                           GET_SIZE);
 485
 486         if(info == NULL) {
 487                 fprintf(stderr, "%s: Error reading sysfs information of %s\n", prg, argv[1]);
 488                 exit_err = 9;
 489                 goto exitHere;
 490         }
 491
 492         if(info->array.level != level) {
 493                 fprintf(stderr, "%s: %s not a RAID-6\n", prg, argv[1]);
 494                 exit_err = 3;
 495                 goto exitHere;
 496         }
 497
 498         if(info->array.failed_disks > 0) {
 499                 fprintf(stderr, "%s: %s degraded array\n", prg, argv[1]);
 500                 exit_err = 8;
 501                 goto exitHere;
 502         }
 503
 504         printf("layout: %d\n", info->array.layout);
 505         printf("disks: %d\n", info->array.raid_disks);
 506         printf("component size: %llu\n", info->component_size * 512);
 507         printf("total stripes: %llu\n", (info->component_size * 512) / info->array.chunk_size);
 508         printf("chunk size: %d\n", info->array.chunk_size);
 509         printf("\n");
 510
 511         comp = info->devs;
 512         for(i = 0, active_disks = 0; active_disks < info->array.raid_disks; i++) {
 513                 printf("disk: %d - offset: %llu - size: %llu - name: %s - slot: %d\n",
 514                         i, comp->data_offset * 512, comp->component_size * 512,
 515                         map_dev(comp->disk.major, comp->disk.minor, 0),
 516                         comp->disk.raid_disk);
 517                 if(comp->disk.raid_disk >= 0)
 518                         active_disks++;
 519                 comp = comp->next;
 520         }
 521         printf("\n");
 522
 523         close(mdfd);
 524
 525         raid_disks = info->array.raid_disks;
 526         chunk_size = info->array.chunk_size;
 527         layout = info->array.layout;
 528         if (strcmp(argv[2], "repair")==0) {
 529                 if (argc < 6) {
 530                         fprintf(stderr, "For repair mode, call %s md_device repair stripe failed_slot_1 failed_slot_2\n", prg);
 531                         exit_err = 1;
 532                         goto exitHere;
 533                 }
 534                 repair = MANUAL_REPAIR;
 535                 start = getnum(argv[3], &err);
 536                 length = 1;
 537                 failed_disk1 = getnum(argv[4], &err);
 538                 failed_disk2 = getnum(argv[5], &err);
 539
 540                 if(failed_disk1 >= info->array.raid_disks) {
 541                         fprintf(stderr, "%s: failed_slot_1 index is higher than number of devices in raid\n", prg);
 542                         exit_err = 4;
 543                         goto exitHere;
 544                 }
 545                 if(failed_disk2 >= info->array.raid_disks) {
 546                         fprintf(stderr, "%s: failed_slot_2 index is higher than number of devices in raid\n", prg);
 547                         exit_err = 4;
 548                         goto exitHere;
 549                 }
 550                 if(failed_disk1 == failed_disk2) {
 551                         fprintf(stderr, "%s: failed_slot_1 and failed_slot_2 are the same\n", prg);
 552                         exit_err = 4;
 553                         goto exitHere;
 554                 }
 555         }
 556         else {
 557                 start = getnum(argv[2], &err);
 558                 length = getnum(argv[3], &err);
 559                 if (argc >= 5 && strcmp(argv[4], "autorepair")==0)
 560                         repair = AUTO_REPAIR;
 561         }
 562
 563         if (err) {
 564                 fprintf(stderr, "%s: Bad number: %s\n", prg, err);
 565                 exit_err = 4;
 566                 goto exitHere;
 567         }
 568
 569         if(start > ((info->component_size * 512) / chunk_size)) {
 570                 start = (info->component_size * 512) / chunk_size;
 571                 fprintf(stderr, "%s: start beyond disks size\n", prg);
 572         }
 573
 574         if((length == 0) ||
 575            ((length + start) > ((info->component_size * 512) / chunk_size))) {
 576                 length = (info->component_size * 512) / chunk_size - start;
 577         }
 578
 579         disk_name = xmalloc(raid_disks * sizeof(*disk_name));
 580         fds = xmalloc(raid_disks * sizeof(*fds));
 581         offsets = xcalloc(raid_disks, sizeof(*offsets));
 582         buf = xmalloc(raid_disks * chunk_size);
 583
 584         for(i=0; i<raid_disks; i++) {
 585                 fds[i] = -1;
 586         }
 587         close_flag = 1;
 588
 589         comp = info->devs;
 590         for (i=0, active_disks=0; active_disks<raid_disks; i++) {
 591                 int disk_slot = comp->disk.raid_disk;
 592                 if(disk_slot >= 0) {
 593                         disk_name[disk_slot] = map_dev(comp->disk.major, comp->disk.minor, 0);
 594                         offsets[disk_slot] = comp->data_offset * 512;
 595                         fds[disk_slot] = open(disk_name[disk_slot], O_RDWR);
 596                         if (fds[disk_slot] < 0) {
 597                                 perror(disk_name[disk_slot]);
 598                                 fprintf(stderr,"%s: cannot open %s\n", prg, disk_name[disk_slot]);
 599                                 exit_err = 6;
 600                                 goto exitHere;
 601                         }
 602                         active_disks++;
 603                 }
 604                 comp = comp->next;
 605         }
 606
 607         int rv = check_stripes(info, fds, offsets,
 608                                raid_disks, chunk_size, level, layout,
 609                                start, length, disk_name, repair, failed_disk1, failed_disk2);
 610         if (rv != 0) {
 611                 fprintf(stderr,
 612                         "%s: check_stripes returned %d\n", prg, rv);
 613                 exit_err = 7;
 614                 goto exitHere;
 615         }
 616
 617 exitHere:
 618
 619         if (close_flag)
 620                 for(i = 0; i < raid_disks; i++)
 621                         close(fds[i]);
 622
 623         free(disk_name);
 624         free(fds);
 625         free(offsets);
 626         free(buf);
 627
 628         exit(exit_err);
 629 }