disk/raid.c

   1 /* raid.c - module to read RAID arrays.  */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2006,2007,2008  Free Software Foundation, Inc.
   5  *
   6  *  GRUB is free software: you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation, either version 3 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  GRUB is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <grub/dl.h>
  21 #include <grub/disk.h>
  22 #include <grub/mm.h>
  23 #include <grub/err.h>
  24 #include <grub/misc.h>
  25 #include <grub/raid.h>
  26
  27 /* Linked list of RAID arrays. */
  28 static struct grub_raid_array *array_list;
  29 grub_raid5_recover_func_t grub_raid5_recover_func;
  30 grub_raid6_recover_func_t grub_raid6_recover_func;
  31
  32 \f
  33 static char
  34 grub_is_array_readable (struct grub_raid_array *array)
  35 {
  36   switch (array->level)
  37     {
  38     case 0:
  39       if (array->nr_devs == array->total_devs)
  40         return 1;
  41       break;
  42
  43     case 1:
  44       if (array->nr_devs >= 1)
  45         return 1;
  46       break;
  47
  48     case 4:
  49     case 5:
  50     case 6:
  51     case 10:
  52       {
  53         unsigned int n;
  54
  55         if (array->level == 10)
  56           {
  57             n = array->layout & 0xFF;
  58             if (n == 1)
  59               n = (array->layout >> 8) & 0xFF;
  60
  61             n--;
  62           }
  63         else
  64           n = array->level / 3;
  65
  66         if (array->nr_devs >= array->total_devs - n)
  67           return 1;
  68
  69         break;
  70       }
  71     }
  72
  73   return 0;
  74 }
  75
  76 static int
  77 grub_raid_iterate (int (*hook) (const char *name))
  78 {
  79   struct grub_raid_array *array;
  80
  81   for (array = array_list; array != NULL; array = array->next)
  82     {
  83       if (grub_is_array_readable (array))
  84         if (hook (array->name))
  85           return 1;
  86     }
  87
  88   return 0;
  89 }
  90
  91 #ifdef GRUB_UTIL
  92 static grub_disk_memberlist_t
  93 grub_raid_memberlist (grub_disk_t disk)
  94 {
  95   struct grub_raid_array *array = disk->data;
  96   grub_disk_memberlist_t list = NULL, tmp;
  97   unsigned int i;
  98
  99   for (i = 0; i < array->total_devs; i++)
 100     if (array->device[i])
 101       {
 102         tmp = grub_malloc (sizeof (*tmp));
 103         tmp->disk = array->device[i];
 104         tmp->next = list;
 105         list = tmp;
 106       }
 107
 108   return list;
 109 }
 110 #endif
 111
 112 static grub_err_t
 113 grub_raid_open (const char *name, grub_disk_t disk)
 114 {
 115   struct grub_raid_array *array;
 116   unsigned n;
 117
 118   for (array = array_list; array != NULL; array = array->next)
 119     {
 120       if (!grub_strcmp (array->name, name))
 121         if (grub_is_array_readable (array))
 122           break;
 123     }
 124
 125   if (!array)
 126     return grub_error (GRUB_ERR_UNKNOWN_DEVICE, "Unknown RAID device %s",
 127                        name);
 128
 129   disk->has_partitions = 1;
 130   disk->id = array->number;
 131   disk->data = array;
 132
 133   grub_dprintf ("raid", "%s: total_devs=%d, disk_size=%lld\n", name,
 134                 array->total_devs, (unsigned long long) array->disk_size);
 135
 136   switch (array->level)
 137     {
 138     case 1:
 139       disk->total_sectors = array->disk_size;
 140       break;
 141
 142     case 10:
 143       n = array->layout & 0xFF;
 144       if (n == 1)
 145         n = (array->layout >> 8) & 0xFF;
 146
 147       disk->total_sectors = grub_divmod64 (array->total_devs *
 148                                            array->disk_size,
 149                                            n, 0);
 150       break;
 151
 152     case 0:
 153     case 4:
 154     case 5:
 155     case 6:
 156       n = array->level / 3;
 157
 158       disk->total_sectors = (array->total_devs - n) * array->disk_size;
 159       break;
 160     }
 161
 162   grub_dprintf ("raid", "%s: level=%d, total_sectors=%lld\n", name,
 163                 array->level, (unsigned long long) disk->total_sectors);
 164
 165   return 0;
 166 }
 167
 168 static void
 169 grub_raid_close (grub_disk_t disk __attribute ((unused)))
 170 {
 171   return;
 172 }
 173
 174 void
 175 grub_raid_block_xor (char *buf1, const char *buf2, int size)
 176 {
 177   grub_size_t *p1;
 178   const grub_size_t *p2;
 179
 180   p1 = (grub_size_t *) buf1;
 181   p2 = (const grub_size_t *) buf2;
 182   size /= GRUB_CPU_SIZEOF_VOID_P;
 183
 184   while (size)
 185     {
 186       *(p1++) ^= *(p2++);
 187       size--;
 188     }
 189 }
 190
 191 static grub_err_t
 192 grub_raid_read (grub_disk_t disk, grub_disk_addr_t sector,
 193                 grub_size_t size, char *buf)
 194 {
 195   struct grub_raid_array *array = disk->data;
 196   grub_err_t err = 0;
 197
 198   switch (array->level)
 199     {
 200     case 0:
 201     case 1:
 202     case 10:
 203       {
 204         grub_disk_addr_t read_sector, far_ofs;
 205         grub_uint32_t disknr, b, near, far, ofs;
 206
 207         read_sector = grub_divmod64 (sector, array->chunk_size, &b);
 208         far = ofs = near = 1;
 209         far_ofs = 0;
 210
 211         if (array->level == 1)
 212           near = array->total_devs;
 213         else if (array->level == 10)
 214           {
 215             near = array->layout & 0xFF;
 216             far = (array->layout >> 8) & 0xFF;
 217             if (array->layout >> 16)
 218               {
 219                 ofs = far;
 220                 far_ofs = 1;
 221               }
 222             else
 223               far_ofs = grub_divmod64 (array->disk_size,
 224                                        far * array->chunk_size, 0);
 225
 226             far_ofs *= array->chunk_size;
 227           }
 228
 229         read_sector = grub_divmod64 (read_sector * near, array->total_devs,
 230                                      &disknr);
 231
 232         ofs *= array->chunk_size;
 233         read_sector *= ofs;
 234
 235         while (1)
 236           {
 237             grub_size_t read_size;
 238             unsigned int i, j;
 239
 240             read_size = array->chunk_size - b;
 241             if (read_size > size)
 242               read_size = size;
 243
 244             for (i = 0; i < near; i++)
 245               {
 246                 unsigned int k;
 247
 248                 k = disknr;
 249                 for (j = 0; j < far; j++)
 250                   {
 251                     if (array->device[k])
 252                       {
 253                         if (grub_errno == GRUB_ERR_READ_ERROR)
 254                           grub_errno = GRUB_ERR_NONE;
 255
 256                         err = grub_disk_read (array->device[k],
 257                                               read_sector + j * far_ofs + b,
 258                                               0,
 259                                               read_size << GRUB_DISK_SECTOR_BITS,
 260                                               buf);
 261                         if (! err)
 262                           break;
 263                         else if (err != GRUB_ERR_READ_ERROR)
 264                           return err;
 265                       }
 266                     else
 267                       err = grub_error (GRUB_ERR_READ_ERROR,
 268                                         "disk missing.");
 269
 270                     k++;
 271                     if (k == array->total_devs)
 272                       k = 0;
 273                   }
 274
 275                 if (! err)
 276                   break;
 277
 278                 disknr++;
 279                 if (disknr == array->total_devs)
 280                   {
 281                     disknr = 0;
 282                     read_sector += ofs;
 283                   }
 284               }
 285
 286             if (err)
 287               return err;
 288
 289             buf += read_size << GRUB_DISK_SECTOR_BITS;
 290             size -= read_size;
 291             if (! size)
 292               break;
 293
 294             b = 0;
 295             disknr += (near - i);
 296             while (disknr >= array->total_devs)
 297               {
 298                 disknr -= array->total_devs;
 299                 read_sector += ofs;
 300               }
 301           }
 302         break;
 303       }
 304
 305     case 4:
 306     case 5:
 307     case 6:
 308       {
 309         grub_disk_addr_t read_sector;
 310         grub_uint32_t b, p, n, disknr, e;
 311
 312         /* n = 1 for level 4 and 5, 2 for level 6.  */
 313         n = array->level / 3;
 314
 315         /* Find the first sector to read. */
 316         read_sector = grub_divmod64 (sector, array->chunk_size, &b);
 317         read_sector = grub_divmod64 (read_sector, array->total_devs - n,
 318                                      &disknr);
 319         if (array->level >= 5)
 320           {
 321             grub_divmod64 (read_sector, array->total_devs, &p);
 322
 323             if (! (array->layout & GRUB_RAID_LAYOUT_RIGHT_MASK))
 324               p = array->total_devs - 1 - p;
 325
 326             if (array->layout & GRUB_RAID_LAYOUT_SYMMETRIC_MASK)
 327               {
 328                 disknr += p + n;
 329               }
 330             else
 331               {
 332                 grub_uint32_t q;
 333
 334                 q = p + (n - 1);
 335                 if (q >= array->total_devs)
 336                   q -= array->total_devs;
 337
 338                 if (disknr >= p)
 339                   disknr += n;
 340                 else if (disknr >= q)
 341                   disknr += q + 1;
 342               }
 343
 344             if (disknr >= array->total_devs)
 345               disknr -= array->total_devs;
 346           }
 347         else
 348           p = array->total_devs - n;
 349
 350         read_sector *= array->chunk_size;
 351
 352         while (1)
 353           {
 354             grub_size_t read_size;
 355             int next_level;
 356
 357             read_size = array->chunk_size - b;
 358             if (read_size > size)
 359               read_size = size;
 360
 361             e = 0;
 362             if (array->device[disknr])
 363               {
 364                 /* Reset read error.  */
 365                 if (grub_errno == GRUB_ERR_READ_ERROR)
 366                   grub_errno = GRUB_ERR_NONE;
 367
 368                 err = grub_disk_read (array->device[disknr],
 369                                       read_sector + b, 0,
 370                                       read_size << GRUB_DISK_SECTOR_BITS,
 371                                       buf);
 372
 373                 if ((err) && (err != GRUB_ERR_READ_ERROR))
 374                   break;
 375                 e++;
 376               }
 377             else
 378               err = GRUB_ERR_READ_ERROR;
 379
 380             if (err)
 381               {
 382                 if (array->nr_devs < array->total_devs - n + e)
 383                   break;
 384
 385                 grub_errno = GRUB_ERR_NONE;
 386                 if (array->level == 6)
 387                   {
 388                     err = ((grub_raid6_recover_func) ?
 389                            (*grub_raid6_recover_func) (array, disknr, p,
 390                                                        buf, read_sector + b,
 391                                                        read_size) :
 392                            grub_error (GRUB_ERR_BAD_DEVICE,
 393                                        "raid6rec is not loaded"));
 394                   }
 395                 else
 396                   {
 397                     err = ((grub_raid5_recover_func) ?
 398                            (*grub_raid5_recover_func) (array, disknr,
 399                                                        buf, read_sector + b,
 400                                                        read_size) :
 401                            grub_error (GRUB_ERR_BAD_DEVICE,
 402                                        "raid5rec is not loaded"));
 403                   }
 404
 405                 if (err)
 406                   break;
 407               }
 408
 409             buf += read_size << GRUB_DISK_SECTOR_BITS;
 410             size -= read_size;
 411             if (! size)
 412               break;
 413
 414             b = 0;
 415             disknr++;
 416
 417             if (array->layout & GRUB_RAID_LAYOUT_SYMMETRIC_MASK)
 418               {
 419                 if (disknr == array->total_devs)
 420                   disknr = 0;
 421
 422                 next_level = (disknr == p);
 423               }
 424             else
 425               {
 426                 if (disknr == p)
 427                   disknr += n;
 428
 429                 next_level = (disknr >= array->total_devs);
 430               }
 431
 432             if (next_level)
 433               {
 434                 read_sector += array->chunk_size;
 435
 436                 if (array->level >= 5)
 437                   {
 438                     if (array->layout & GRUB_RAID_LAYOUT_RIGHT_MASK)
 439                       p = (p == array->total_devs - 1) ? 0 : p + 1;
 440                     else
 441                       p = (p == 0) ? array->total_devs - 1 : p - 1;
 442
 443                     if (array->layout & GRUB_RAID_LAYOUT_SYMMETRIC_MASK)
 444                       {
 445                         disknr = p + n;
 446                         if (disknr >= array->total_devs)
 447                           disknr -= array->total_devs;
 448                       }
 449                     else
 450                       {
 451                         disknr -= array->total_devs;
 452                         if (disknr == p)
 453                           disknr += n;
 454                       }
 455                   }
 456                 else
 457                   disknr = 0;
 458               }
 459           }
 460       }
 461       break;
 462     }
 463
 464   return err;
 465 }
 466
 467 static grub_err_t
 468 grub_raid_write (grub_disk_t disk __attribute ((unused)),
 469                  grub_disk_addr_t sector __attribute ((unused)),
 470                  grub_size_t size __attribute ((unused)),
 471                  const char *buf __attribute ((unused)))
 472 {
 473   return GRUB_ERR_NOT_IMPLEMENTED_YET;
 474 }
 475
 476 static grub_err_t
 477 insert_array (grub_disk_t disk, struct grub_raid_array *new_array,
 478               const char *scanner_name)
 479 {
 480   struct grub_raid_array *array = 0, *p;
 481
 482   /* See whether the device is part of an array we have already seen a
 483      device from. */
 484   for (p = array_list; p != NULL; p = p->next)
 485     if ((p->uuid_len == new_array->uuid_len) &&
 486         (! grub_memcmp (p->uuid, new_array->uuid, p->uuid_len)))
 487       {
 488         grub_free (new_array->uuid);
 489         array = p;
 490
 491         /* Do some checks before adding the device to the array.  */
 492
 493         /* FIXME: Check whether the update time of the superblocks are
 494            the same. */
 495
 496         if (array->total_devs == array->nr_devs)
 497           /* We found more members of the array than the array
 498              actually has according to its superblock.  This shouldn't
 499              happen normally.  */
 500           grub_dprintf ("raid", "array->nr_devs > array->total_devs (%d)?!?",
 501                         array->total_devs);
 502
 503         if (array->device[new_array->index] != NULL)
 504           /* We found multiple devices with the same number. Again,
 505              this shouldn't happen.*/
 506           grub_dprintf ("raid", "Found two disks with the number %d?!?",
 507                         new_array->number);
 508
 509         if (new_array->disk_size < array->disk_size)
 510           array->disk_size = new_array->disk_size;
 511         break;
 512       }
 513
 514   /* Add an array to the list if we didn't find any.  */
 515   if (!array)
 516     {
 517       array = grub_malloc (sizeof (*array));
 518       if (!array)
 519         {
 520           grub_free (new_array->uuid);
 521           return grub_errno;
 522         }
 523
 524       *array = *new_array;
 525       array->nr_devs = 0;
 526       grub_memset (&array->device, 0, sizeof (array->device));
 527
 528       /* Check whether we don't have multiple arrays with the same number. */
 529       for (p = array_list; p != NULL; p = p->next)
 530         {
 531           if (p->number == array->number)
 532             break;
 533         }
 534
 535       if (p)
 536         {
 537           /* The number is already in use, so we need to find an new number. */
 538           int i = 0;
 539
 540           while (1)
 541             {
 542               for (p = array_list; p != NULL; p = p->next)
 543                 {
 544                   if (p->number == i)
 545                     break;
 546                 }
 547
 548               if (!p)
 549                 {
 550                   /* We found an unused number.  */
 551                   array->number = i;
 552                   break;
 553                 }
 554
 555               i++;
 556             }
 557         }
 558
 559       array->name = grub_malloc (13);
 560       if (! array->name)
 561         {
 562           grub_free (array->uuid);
 563           grub_free (array);
 564
 565           return grub_errno;
 566         }
 567
 568       grub_sprintf (array->name, "md%d", array->number);
 569
 570       grub_dprintf ("raid", "Found array %s (%s)\n", array->name,
 571                     scanner_name);
 572
 573       /* Add our new array to the list.  */
 574       array->next = array_list;
 575       array_list = array;
 576
 577       /* RAID 1 doesn't use a chunksize but code assumes one so set
 578          one. */
 579       if (array->level == 1)
 580         array->chunk_size = 64;
 581     }
 582
 583   /* Add the device to the array. */
 584   array->device[new_array->index] = disk;
 585   array->nr_devs++;
 586
 587   return 0;
 588 }
 589
 590 static grub_raid_t grub_raid_list;
 591
 592 static void
 593 free_array (void)
 594 {
 595   struct grub_raid_array *array;
 596
 597   array = array_list;
 598   while (array)
 599     {
 600       struct grub_raid_array *p;
 601       int i;
 602
 603       p = array;
 604       array = array->next;
 605
 606       for (i = 0; i < GRUB_RAID_MAX_DEVICES; i++)
 607         if (p->device[i])
 608           grub_disk_close (p->device[i]);
 609
 610       grub_free (p->uuid);
 611       grub_free (p->name);
 612       grub_free (p);
 613     }
 614
 615   array_list = 0;
 616 }
 617
 618 void
 619 grub_raid_register (grub_raid_t raid)
 620 {
 621   auto int hook (const char *name);
 622   int hook (const char *name)
 623     {
 624       grub_disk_t disk;
 625       struct grub_raid_array array;
 626
 627       grub_dprintf ("raid", "Scanning for RAID devices on disk %s\n", name);
 628
 629       disk = grub_disk_open (name);
 630       if (!disk)
 631         return 0;
 632
 633       if ((disk->total_sectors != GRUB_ULONG_MAX) &&
 634           (! grub_raid_list->detect (disk, &array)) &&
 635           (! insert_array (disk, &array, grub_raid_list->name)))
 636         return 0;
 637
 638       /* This error usually means it's not raid, no need to display
 639          it.  */
 640       if (grub_errno != GRUB_ERR_OUT_OF_RANGE)
 641         grub_print_error ();
 642
 643       grub_errno = GRUB_ERR_NONE;
 644
 645       grub_disk_close (disk);
 646
 647       return 0;
 648     }
 649
 650   raid->next = grub_raid_list;
 651   grub_raid_list = raid;
 652   grub_device_iterate (&hook);
 653 }
 654
 655 void
 656 grub_raid_unregister (grub_raid_t raid)
 657 {
 658   grub_raid_t *p, q;
 659
 660   for (p = &grub_raid_list, q = *p; q; p = &(q->next), q = q->next)
 661     if (q == raid)
 662       {
 663         *p = q->next;
 664         break;
 665       }
 666 }
 667
 668 static struct grub_disk_dev grub_raid_dev =
 669   {
 670     .name = "raid",
 671     .id = GRUB_DISK_DEVICE_RAID_ID,
 672     .iterate = grub_raid_iterate,
 673     .open = grub_raid_open,
 674     .close = grub_raid_close,
 675     .read = grub_raid_read,
 676     .write = grub_raid_write,
 677 #ifdef GRUB_UTIL
 678     .memberlist = grub_raid_memberlist,
 679 #endif
 680     .next = 0
 681   };
 682
 683 \f
 684 GRUB_MOD_INIT(raid)
 685 {
 686   grub_disk_dev_register (&grub_raid_dev);
 687 }
 688
 689 GRUB_MOD_FINI(raid)
 690 {
 691   grub_disk_dev_unregister (&grub_raid_dev);
 692   free_array ();
 693 }