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