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
  35 /* Collect per stripe consistency information */
  36 void raid6_collect(int chunk_size, uint8_t *p, uint8_t *q,
  37                    char *chunkP, char *chunkQ, int *results)
  38 {
  39         int i;
  40         int data_id;
  41         uint8_t Px, Qx;
  42         extern uint8_t raid6_gflog[];
  43
  44         for(i = 0; i < chunk_size; i++) {
  45                 Px = (uint8_t)chunkP[i] ^ (uint8_t)p[i];
  46                 Qx = (uint8_t)chunkQ[i] ^ (uint8_t)q[i];
  47
  48                 if((Px != 0) && (Qx == 0))
  49                         results[i] = -1;
  50
  51                 if((Px == 0) && (Qx != 0))
  52                         results[i] = -2;
  53
  54                 if((Px != 0) && (Qx != 0)) {
  55                         data_id = (raid6_gflog[Qx] - raid6_gflog[Px]);
  56                         if(data_id < 0) data_id += 255;
  57                         results[i] = data_id;
  58                 }
  59
  60                 if((Px == 0) && (Qx == 0))
  61                         results[i] = -255;
  62         }
  63 }
  64
  65 /* Try to find out if a specific disk has problems */
  66 int raid6_stats(int *results, int raid_disks, int chunk_size)
  67 {
  68         int i;
  69         int curr_broken_disk = -255;
  70         int prev_broken_disk = -255;
  71         int broken_status = 0;
  72
  73         for(i = 0; i < chunk_size; i++) {
  74
  75                 if(results[i] != -255)
  76                         curr_broken_disk = results[i];
  77
  78                 if(curr_broken_disk >= raid_disks)
  79                         broken_status = 2;
  80
  81                 switch(broken_status) {
  82                 case 0:
  83                         if(curr_broken_disk != -255) {
  84                                 prev_broken_disk = curr_broken_disk;
  85                                 broken_status = 1;
  86                         }
  87                         break;
  88
  89                 case 1:
  90                         if(curr_broken_disk != prev_broken_disk)
  91                                 broken_status = 2;
  92                         break;
  93
  94                 case 2:
  95                 default:
  96                         curr_broken_disk = prev_broken_disk = -65535;
  97                         break;
  98                 }
  99         }
 100
 101         return curr_broken_disk;
 102 }
 103
 104 int check_stripes(struct mdinfo *info, int *source, unsigned long long *offsets,
 105                   int raid_disks, int chunk_size, int level, int layout,
 106                   unsigned long long start, unsigned long long length, char *name[])
 107 {
 108         /* read the data and p and q blocks, and check we got them right */
 109         char *stripe_buf = xmalloc(raid_disks * chunk_size);
 110         char **stripes = xmalloc(raid_disks * sizeof(char*));
 111         char **blocks = xmalloc(raid_disks * sizeof(char*));
 112         uint8_t *p = xmalloc(chunk_size);
 113         uint8_t *q = xmalloc(chunk_size);
 114         int *results = xmalloc(chunk_size * sizeof(int));
 115
 116         int i;
 117         int diskP, diskQ;
 118         int data_disks = raid_disks - 2;
 119         int err = 0;
 120         sighandler_t sig[3];
 121         int rv;
 122
 123         extern int tables_ready;
 124
 125         if (!tables_ready)
 126                 make_tables();
 127
 128         for ( i = 0 ; i < raid_disks ; i++)
 129                 stripes[i] = stripe_buf + i * chunk_size;
 130
 131         while (length > 0) {
 132                 int disk;
 133
 134                 printf("pos --> %llu\n", start);
 135
 136                 if(mlockall(MCL_CURRENT | MCL_FUTURE) != 0) {
 137                         err = 2;
 138                         goto exitCheck;
 139                 }
 140                 sig[0] = signal(SIGTERM, SIG_IGN);
 141                 sig[1] = signal(SIGINT, SIG_IGN);
 142                 sig[2] = signal(SIGQUIT, SIG_IGN);
 143                 rv = sysfs_set_num(info, NULL, "suspend_lo", start * chunk_size * data_disks);
 144                 rv |= sysfs_set_num(info, NULL, "suspend_hi", (start + 1) * chunk_size * data_disks);
 145                 for (i = 0 ; i < raid_disks ; i++) {
 146                         lseek64(source[i], offsets[i] + start * chunk_size, 0);
 147                         read(source[i], stripes[i], chunk_size);
 148                 }
 149                 rv |= sysfs_set_num(info, NULL, "suspend_lo", 0x7FFFFFFFFFFFFFFFULL);
 150                 rv |= sysfs_set_num(info, NULL, "suspend_hi", 0);
 151                 rv |= sysfs_set_num(info, NULL, "suspend_lo", 0);
 152                 signal(SIGQUIT, sig[2]);
 153                 signal(SIGINT, sig[1]);
 154                 signal(SIGTERM, sig[0]);
 155                 if(munlockall() != 0) {
 156                         err = 3;
 157                         goto exitCheck;
 158                 }
 159
 160                 if(rv != 0) {
 161                         err = rv * 256;
 162                         goto exitCheck;
 163                 }
 164
 165                 for (i = 0 ; i < data_disks ; i++) {
 166                         int disk = geo_map(i, start, raid_disks, level, layout);
 167                         blocks[i] = stripes[disk];
 168                         printf("%d->%d\n", i, disk);
 169                 }
 170
 171                 qsyndrome(p, q, (uint8_t**)blocks, data_disks, chunk_size);
 172                 diskP = geo_map(-1, start, raid_disks, level, layout);
 173                 if (memcmp(p, stripes[diskP], chunk_size) != 0) {
 174                         printf("P(%d) wrong at %llu\n", diskP, start);
 175                 }
 176                 diskQ = geo_map(-2, start, raid_disks, level, layout);
 177                 if (memcmp(q, stripes[diskQ], chunk_size) != 0) {
 178                         printf("Q(%d) wrong at %llu\n", diskQ, start);
 179                 }
 180                 raid6_collect(chunk_size, p, q, stripes[diskP], stripes[diskQ], results);
 181                 disk = raid6_stats(results, raid_disks, chunk_size);
 182
 183                 if(disk >= -2) {
 184                         disk = geo_map(disk, start, raid_disks, level, layout);
 185                 }
 186                 if(disk >= 0) {
 187                         printf("Error detected at %llu: possible failed disk slot: %d --> %s\n",
 188                                 start, disk, name[disk]);
 189                 }
 190                 if(disk == -65535) {
 191                         printf("Error detected at %llu: disk slot unknown\n", start);
 192                 }
 193
 194                 length--;
 195                 start++;
 196         }
 197
 198 exitCheck:
 199
 200         free(stripe_buf);
 201         free(stripes);
 202         free(blocks);
 203         free(p);
 204         free(q);
 205         free(results);
 206
 207         return err;
 208 }
 209
 210 unsigned long long getnum(char *str, char **err)
 211 {
 212         char *e;
 213         unsigned long long rv = strtoull(str, &e, 10);
 214         if (e==str || *e) {
 215                 *err = str;
 216                 return 0;
 217         }
 218         return rv;
 219 }
 220
 221 int main(int argc, char *argv[])
 222 {
 223         /* md_device start length */
 224         int *fds = NULL;
 225         char *buf = NULL;
 226         char **disk_name = NULL;
 227         unsigned long long *offsets = NULL;
 228         int raid_disks = 0;
 229         int active_disks;
 230         int chunk_size = 0;
 231         int layout = -1;
 232         int level = 6;
 233         unsigned long long start, length;
 234         int i;
 235         int mdfd;
 236         struct mdinfo *info = NULL, *comp = NULL;
 237         char *err = NULL;
 238         int exit_err = 0;
 239         int close_flag = 0;
 240         char *prg = strrchr(argv[0], '/');
 241
 242         if (prg == NULL)
 243                 prg = argv[0];
 244         else
 245                 prg++;
 246
 247         if (argc < 4) {
 248                 fprintf(stderr, "Usage: %s md_device start_stripe length_stripes\n", prg);
 249                 exit_err = 1;
 250                 goto exitHere;
 251         }
 252
 253         mdfd = open(argv[1], O_RDONLY);
 254         if(mdfd < 0) {
 255                 perror(argv[1]);
 256                 fprintf(stderr, "%s: cannot open %s\n", prg, argv[1]);
 257                 exit_err = 2;
 258                 goto exitHere;
 259         }
 260
 261         info = sysfs_read(mdfd, -1,
 262                           GET_LEVEL|
 263                           GET_LAYOUT|
 264                           GET_DISKS|
 265                           GET_DEGRADED |
 266                           GET_COMPONENT|
 267                           GET_CHUNK|
 268                           GET_DEVS|
 269                           GET_OFFSET|
 270                           GET_SIZE);
 271
 272         if(info == NULL) {
 273                 fprintf(stderr, "%s: Error reading sysfs information of %s\n", prg, argv[1]);
 274                 exit_err = 9;
 275                 goto exitHere;
 276         }
 277
 278         if(info->array.level != level) {
 279                 fprintf(stderr, "%s: %s not a RAID-6\n", prg, argv[1]);
 280                 exit_err = 3;
 281                 goto exitHere;
 282         }
 283
 284         if(info->array.failed_disks > 0) {
 285                 fprintf(stderr, "%s: %s degraded array\n", prg, argv[1]);
 286                 exit_err = 8;
 287                 goto exitHere;
 288         }
 289
 290         printf("layout: %d\n", info->array.layout);
 291         printf("disks: %d\n", info->array.raid_disks);
 292         printf("component size: %llu\n", info->component_size * 512);
 293         printf("total stripes: %llu\n", (info->component_size * 512) / info->array.chunk_size);
 294         printf("chunk size: %d\n", info->array.chunk_size);
 295         printf("\n");
 296
 297         comp = info->devs;
 298         for(i = 0, active_disks = 0; active_disks < info->array.raid_disks; i++) {
 299                 printf("disk: %d - offset: %llu - size: %llu - name: %s - slot: %d\n",
 300                         i, comp->data_offset * 512, comp->component_size * 512,
 301                         map_dev(comp->disk.major, comp->disk.minor, 0),
 302                         comp->disk.raid_disk);
 303                 if(comp->disk.raid_disk >= 0)
 304                         active_disks++;
 305                 comp = comp->next;
 306         }
 307         printf("\n");
 308
 309         close(mdfd);
 310
 311         raid_disks = info->array.raid_disks;
 312         chunk_size = info->array.chunk_size;
 313         layout = info->array.layout;
 314         start = getnum(argv[2], &err);
 315         length = getnum(argv[3], &err);
 316
 317         if (err) {
 318                 fprintf(stderr, "%s: Bad number: %s\n", prg, err);
 319                 exit_err = 4;
 320                 goto exitHere;
 321         }
 322
 323         if(start > ((info->component_size * 512) / chunk_size)) {
 324                 start = (info->component_size * 512) / chunk_size;
 325                 fprintf(stderr, "%s: start beyond disks size\n", prg);
 326         }
 327
 328         if((length == 0) ||
 329            ((length + start) > ((info->component_size * 512) / chunk_size))) {
 330                 length = (info->component_size * 512) / chunk_size - start;
 331         }
 332
 333         disk_name = xmalloc(raid_disks * sizeof(*disk_name));
 334         fds = xmalloc(raid_disks * sizeof(*fds));
 335         offsets = xcalloc(raid_disks, sizeof(*offsets));
 336         buf = xmalloc(raid_disks * chunk_size);
 337
 338         for(i=0; i<raid_disks; i++) {
 339                 fds[i] = -1;
 340         }
 341         close_flag = 1;
 342
 343         comp = info->devs;
 344         for (i=0, active_disks=0; active_disks<raid_disks; i++) {
 345                 int disk_slot = comp->disk.raid_disk;
 346                 if(disk_slot >= 0) {
 347                         disk_name[disk_slot] = map_dev(comp->disk.major, comp->disk.minor, 0);
 348                         offsets[disk_slot] = comp->data_offset * 512;
 349                         fds[disk_slot] = open(disk_name[disk_slot], O_RDWR);
 350                         if (fds[disk_slot] < 0) {
 351                                 perror(disk_name[disk_slot]);
 352                                 fprintf(stderr,"%s: cannot open %s\n", prg, disk_name[disk_slot]);
 353                                 exit_err = 6;
 354                                 goto exitHere;
 355                         }
 356                         active_disks++;
 357                 }
 358                 comp = comp->next;
 359         }
 360
 361         int rv = check_stripes(info, fds, offsets,
 362                                raid_disks, chunk_size, level, layout,
 363                                start, length, disk_name);
 364         if (rv != 0) {
 365                 fprintf(stderr,
 366                         "%s: check_stripes returned %d\n", prg, rv);
 367                 exit_err = 7;
 368                 goto exitHere;
 369         }
 370
 371 exitHere:
 372
 373         if (close_flag)
 374                 for(i = 0; i < raid_disks; i++)
 375                         close(fds[i]);
 376
 377         free(disk_name);
 378         free(fds);
 379         free(offsets);
 380         free(buf);
 381
 382         exit(exit_err);
 383 }