root/fs/ext2/balloc.c

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DEFINITIONS

This source file includes following definitions.
  1. get_group_desc
  2. read_block_bitmap
  3. load__block_bitmap
  4. load_block_bitmap
  5. ext2_free_blocks
  6. ext2_new_block
  7. ext2_count_free_blocks
  8. block_in_use
  9. ext2_check_blocks_bitmap

   1 /*
   2  *  linux/fs/ext2/balloc.c
   3  *
   4  *  Copyright (C) 1992, 1993, 1994  Remy Card (card@masi.ibp.fr)
   5  *                                  Laboratoire MASI - Institut Blaise Pascal
   6  *                                  Universite Pierre et Marie Curie (Paris VI)
   7  *
   8  *  Enhanced block allocation by Stephen Tweedie (sct@dcs.ed.ac.uk), 1993
   9  */
  10 
  11 /*
  12  * balloc.c contains the blocks allocation and deallocation routines
  13  */
  14 
  15 /*
  16  * The free blocks are managed by bitmaps.  A file system contains several
  17  * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
  18  * block for inodes, N blocks for the inode table and data blocks.
  19  *
  20  * The file system contains group descriptors which are located after the
  21  * super block.  Each descriptor contains the number of the bitmap block and
  22  * the free blocks count in the block.  The descriptors are loaded in memory
  23  * when a file system is mounted (see ext2_read_super).
  24  */
  25 
  26 #include <linux/fs.h>
  27 #include <linux/ext2_fs.h>
  28 #include <linux/stat.h>
  29 #include <linux/sched.h>
  30 #include <linux/string.h>
  31 #include <linux/locks.h>
  32 
  33 #include <asm/bitops.h>
  34 
  35 #define in_range(b, first, len)         ((b) >= (first) && (b) <= (first) + (len) - 1)
  36 
  37 static struct ext2_group_desc * get_group_desc (struct super_block * sb,
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  38                                                 unsigned int block_group,
  39                                                 struct buffer_head ** bh)
  40 {
  41         unsigned long group_desc;
  42         unsigned long desc;
  43         struct ext2_group_desc * gdp;
  44 
  45         if (block_group >= sb->u.ext2_sb.s_groups_count)
  46                 ext2_panic (sb, "get_group_desc",
  47                             "block_group >= groups_count - "
  48                             "block_group = %d, groups_count = %lu",
  49                             block_group, sb->u.ext2_sb.s_groups_count);
  50 
  51         group_desc = block_group / EXT2_DESC_PER_BLOCK(sb);
  52         desc = block_group % EXT2_DESC_PER_BLOCK(sb);
  53         if (!sb->u.ext2_sb.s_group_desc[group_desc])
  54                 ext2_panic (sb, "get_group_desc",
  55                             "Group descriptor not loaded - "
  56                             "block_group = %d, group_desc = %lu, desc = %lu",
  57                              block_group, group_desc, desc);
  58         gdp = (struct ext2_group_desc *) 
  59               sb->u.ext2_sb.s_group_desc[group_desc]->b_data;
  60         if (bh)
  61                 *bh = sb->u.ext2_sb.s_group_desc[group_desc];
  62         return gdp + desc;
  63 }
  64 
  65 static void read_block_bitmap (struct super_block * sb,
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  66                                unsigned int block_group,
  67                                unsigned long bitmap_nr)
  68 {
  69         struct ext2_group_desc * gdp;
  70         struct buffer_head * bh;
  71         
  72         gdp = get_group_desc (sb, block_group, NULL);
  73         bh = bread (sb->s_dev, gdp->bg_block_bitmap, sb->s_blocksize);
  74         if (!bh)
  75                 ext2_panic (sb, "read_block_bitmap",
  76                             "Cannot read block bitmap - "
  77                             "block_group = %d, block_bitmap = %lu",
  78                             block_group, gdp->bg_block_bitmap);
  79         sb->u.ext2_sb.s_block_bitmap_number[bitmap_nr] = block_group;
  80         sb->u.ext2_sb.s_block_bitmap[bitmap_nr] = bh;
  81 }
  82 
  83 /*
  84  * load_block_bitmap loads the block bitmap for a blocks group
  85  *
  86  * It maintains a cache for the last bitmaps loaded.  This cache is managed
  87  * with a LRU algorithm.
  88  *
  89  * Notes:
  90  * 1/ There is one cache per mounted file system.
  91  * 2/ If the file system contains less than EXT2_MAX_GROUP_LOADED groups,
  92  *    this function reads the bitmap without maintaining a LRU cache.
  93  */
  94 static int load__block_bitmap (struct super_block * sb,
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  95                                unsigned int block_group)
  96 {
  97         int i, j;
  98         unsigned long block_bitmap_number;
  99         struct buffer_head * block_bitmap;
 100 
 101         if (block_group >= sb->u.ext2_sb.s_groups_count)
 102                 ext2_panic (sb, "load_block_bitmap",
 103                             "block_group >= groups_count - "
 104                             "block_group = %d, groups_count = %lu",
 105                             block_group, sb->u.ext2_sb.s_groups_count);
 106 
 107         if (sb->u.ext2_sb.s_groups_count <= EXT2_MAX_GROUP_LOADED) {
 108                 if (sb->u.ext2_sb.s_block_bitmap[block_group]) {
 109                         if (sb->u.ext2_sb.s_block_bitmap_number[block_group] !=
 110                             block_group)
 111                                 ext2_panic (sb, "load_block_bitmap",
 112                                             "block_group != block_bitmap_number");
 113                         else
 114                                 return block_group;
 115                 } else {
 116                         read_block_bitmap (sb, block_group, block_group);
 117                         return block_group;
 118                 }
 119         }
 120 
 121         for (i = 0; i < sb->u.ext2_sb.s_loaded_block_bitmaps &&
 122                     sb->u.ext2_sb.s_block_bitmap_number[i] != block_group; i++)
 123                 ;
 124         if (i < sb->u.ext2_sb.s_loaded_block_bitmaps &&
 125             sb->u.ext2_sb.s_block_bitmap_number[i] == block_group) {
 126                 block_bitmap_number = sb->u.ext2_sb.s_block_bitmap_number[i];
 127                 block_bitmap = sb->u.ext2_sb.s_block_bitmap[i];
 128                 for (j = i; j > 0; j--) {
 129                         sb->u.ext2_sb.s_block_bitmap_number[j] =
 130                                 sb->u.ext2_sb.s_block_bitmap_number[j - 1];
 131                         sb->u.ext2_sb.s_block_bitmap[j] =
 132                                 sb->u.ext2_sb.s_block_bitmap[j - 1];
 133                 }
 134                 sb->u.ext2_sb.s_block_bitmap_number[0] = block_bitmap_number;
 135                 sb->u.ext2_sb.s_block_bitmap[0] = block_bitmap;
 136         } else {
 137                 if (sb->u.ext2_sb.s_loaded_block_bitmaps < EXT2_MAX_GROUP_LOADED)
 138                         sb->u.ext2_sb.s_loaded_block_bitmaps++;
 139                 else
 140                         brelse (sb->u.ext2_sb.s_block_bitmap[EXT2_MAX_GROUP_LOADED - 1]);
 141                 for (j = sb->u.ext2_sb.s_loaded_block_bitmaps - 1; j > 0;  j--) {
 142                         sb->u.ext2_sb.s_block_bitmap_number[j] =
 143                                 sb->u.ext2_sb.s_block_bitmap_number[j - 1];
 144                         sb->u.ext2_sb.s_block_bitmap[j] =
 145                                 sb->u.ext2_sb.s_block_bitmap[j - 1];
 146                 }
 147                 read_block_bitmap (sb, block_group, 0);
 148         }
 149         return 0;
 150 }
 151 
 152 static inline int load_block_bitmap (struct super_block * sb,
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 153                                      unsigned int block_group)
 154 {
 155         if (sb->u.ext2_sb.s_loaded_block_bitmaps > 0 &&
 156             sb->u.ext2_sb.s_block_bitmap_number[0] == block_group)
 157                 return 0;
 158         
 159         if (sb->u.ext2_sb.s_groups_count <= EXT2_MAX_GROUP_LOADED && 
 160             sb->u.ext2_sb.s_block_bitmap_number[block_group] == block_group &&
 161             sb->u.ext2_sb.s_block_bitmap[block_group]) 
 162                 return block_group;
 163 
 164         return load__block_bitmap (sb, block_group);
 165 }
 166 
 167 void ext2_free_blocks (struct super_block * sb, unsigned long block,
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 168                        unsigned long count)
 169 {
 170         struct buffer_head * bh;
 171         struct buffer_head * bh2;
 172         unsigned long block_group;
 173         unsigned long bit;
 174         unsigned long i;
 175         int bitmap_nr;
 176         struct ext2_group_desc * gdp;
 177         struct ext2_super_block * es;
 178 
 179         if (!sb) {
 180                 printk ("ext2_free_blocks: nonexistent device");
 181                 return;
 182         }
 183         lock_super (sb);
 184         es = sb->u.ext2_sb.s_es;
 185         if (block < es->s_first_data_block || 
 186             (block + count) > es->s_blocks_count) {
 187                 ext2_error (sb, "ext2_free_blocks",
 188                             "Freeing blocks not in datazone - "
 189                             "block = %lu, count = %lu", block, count);
 190                 unlock_super (sb);
 191                 return;
 192         }
 193 
 194         ext2_debug ("freeing block %lu\n", block);
 195 
 196         block_group = (block - es->s_first_data_block) /
 197                       EXT2_BLOCKS_PER_GROUP(sb);
 198         bit = (block - es->s_first_data_block) % EXT2_BLOCKS_PER_GROUP(sb);
 199         if (bit + count > EXT2_BLOCKS_PER_GROUP(sb))
 200                 ext2_panic (sb, "ext2_free_blocks",
 201                             "Freeing blocks across group boundary - "
 202                             "Block = %lu, count = %lu",
 203                             block, count);
 204         bitmap_nr = load_block_bitmap (sb, block_group);
 205         bh = sb->u.ext2_sb.s_block_bitmap[bitmap_nr];
 206         gdp = get_group_desc (sb, block_group, &bh2);
 207 
 208         if (test_opt (sb, CHECK_STRICT) &&
 209             (in_range (gdp->bg_block_bitmap, block, count) ||
 210              in_range (gdp->bg_inode_bitmap, block, count) ||
 211              in_range (block, gdp->bg_inode_table,
 212                        sb->u.ext2_sb.s_itb_per_group) ||
 213              in_range (block + count - 1, gdp->bg_inode_table,
 214                        sb->u.ext2_sb.s_itb_per_group)))
 215                 ext2_panic (sb, "ext2_free_blocks",
 216                             "Freeing blocks in system zones - "
 217                             "Block = %lu, count = %lu",
 218                             block, count);
 219 
 220         for (i = 0; i < count; i++) {
 221                 if (!clear_bit (bit + i, bh->b_data))
 222                         ext2_warning (sb, "ext2_free_blocks",
 223                                       "bit already cleared for block %lu", 
 224                                       block);
 225                 else {
 226                         gdp->bg_free_blocks_count++;
 227                         es->s_free_blocks_count++;
 228                 }
 229         }
 230         
 231         mark_buffer_dirty(bh2, 1);
 232         mark_buffer_dirty(sb->u.ext2_sb.s_sbh, 1);
 233 
 234         mark_buffer_dirty(bh, 1);
 235         if (sb->s_flags & MS_SYNCHRONOUS) {
 236                 ll_rw_block (WRITE, 1, &bh);
 237                 wait_on_buffer (bh);
 238         }
 239         sb->s_dirt = 1;
 240         unlock_super (sb);
 241         return;
 242 }
 243 
 244 /*
 245  * ext2_new_block uses a goal block to assist allocation.  If the goal is
 246  * free, or there is a free block within 32 blocks of the goal, that block
 247  * is allocated.  Otherwise a forward search is made for a free block; within 
 248  * each block group the search first looks for an entire free byte in the block
 249  * bitmap, and then for any free bit if that fails.
 250  */
 251 int ext2_new_block (struct super_block * sb, unsigned long goal,
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 252                     unsigned long * prealloc_count,
 253                     unsigned long * prealloc_block)
 254 {
 255         struct buffer_head * bh;
 256         struct buffer_head * bh2;
 257         char * p, * r;
 258         int i, j, k, tmp;
 259         unsigned long lmap;
 260         int bitmap_nr;
 261         struct ext2_group_desc * gdp;
 262         struct ext2_super_block * es;
 263 
 264 #ifdef EXT2FS_DEBUG
 265         static int goal_hits = 0, goal_attempts = 0;
 266 #endif
 267         if (!sb) {
 268                 printk ("ext2_new_block: nonexistent device");
 269                 return 0;
 270         }
 271         lock_super (sb);
 272         es = sb->u.ext2_sb.s_es;
 273         if (es->s_free_blocks_count <= es->s_r_blocks_count &&
 274             (!fsuser() && (sb->u.ext2_sb.s_resuid != current->fsuid) &&
 275              (sb->u.ext2_sb.s_resgid == 0 ||
 276               !in_group_p (sb->u.ext2_sb.s_resgid)))) {
 277                 unlock_super (sb);
 278                 return 0;
 279         }
 280 
 281         ext2_debug ("goal=%lu.\n", goal);
 282 
 283 repeat:
 284         /*
 285          * First, test whether the goal block is free.
 286          */
 287         if (goal < es->s_first_data_block || goal >= es->s_blocks_count)
 288                 goal = es->s_first_data_block;
 289         i = (goal - es->s_first_data_block) / EXT2_BLOCKS_PER_GROUP(sb);
 290         gdp = get_group_desc (sb, i, &bh2);
 291         if (gdp->bg_free_blocks_count > 0) {
 292                 j = ((goal - es->s_first_data_block) % EXT2_BLOCKS_PER_GROUP(sb));
 293 #ifdef EXT2FS_DEBUG
 294                 if (j)
 295                         goal_attempts++;
 296 #endif
 297                 bitmap_nr = load_block_bitmap (sb, i);
 298                 bh = sb->u.ext2_sb.s_block_bitmap[bitmap_nr];
 299 
 300                 ext2_debug ("goal is at %d:%d.\n", i, j);
 301 
 302                 if (!test_bit(j, bh->b_data)) {
 303 #ifdef EXT2FS_DEBUG
 304                         goal_hits++;
 305                         ext2_debug ("goal bit allocated.\n");
 306 #endif
 307                         goto got_block;
 308                 }
 309                 if (j) {
 310                         /*
 311                          * The goal was occupied; search forward for a free 
 312                          * block within the next 32 blocks
 313                          */
 314                         lmap = ((((unsigned long *) bh->b_data)[j >> 5]) >>
 315                                 ((j & 31) + 1));
 316                         if (j < EXT2_BLOCKS_PER_GROUP(sb) - 32)
 317                                 lmap |= (((unsigned long *) bh->b_data)[(j >> 5) + 1]) <<
 318                                  (31 - (j & 31));
 319                         else
 320                                 lmap |= 0xffffffff << (31 - (j & 31));
 321                         if (lmap != 0xffffffffl) {
 322                                 k = ffz(lmap) + 1;
 323                                 if ((j + k) < EXT2_BLOCKS_PER_GROUP(sb)) {
 324                                         j += k;
 325                                         goto got_block;
 326                                 }
 327                         }
 328                 }
 329         
 330                 ext2_debug ("Bit not found near goal\n");
 331 
 332                 /*
 333                  * There has been no free block found in the near vicinity
 334                  * of the goal: do a search forward through the block groups,
 335                  * searching in each group first for an entire free byte in
 336                  * the bitmap and then for any free bit.
 337                  * 
 338                  * Search first in the remainder of the current group; then,
 339                  * cyclicly search through the rest of the groups.
 340                  */
 341                 p = ((char *) bh->b_data) + (j >> 3);
 342                 r = memscan(p, 0, (EXT2_BLOCKS_PER_GROUP(sb) - j + 7) >> 3);
 343                 k = (r - ((char *) bh->b_data)) << 3;
 344                 if (k < EXT2_BLOCKS_PER_GROUP(sb)) {
 345                         j = k;
 346                         goto search_back;
 347                 }
 348                 k = find_next_zero_bit ((unsigned long *) bh->b_data, 
 349                                         EXT2_BLOCKS_PER_GROUP(sb),
 350                                         j);
 351                 if (k < EXT2_BLOCKS_PER_GROUP(sb)) {
 352                         j = k;
 353                         goto got_block;
 354                 }
 355         }
 356 
 357         ext2_debug ("Bit not found in block group %d.\n", i);
 358 
 359         /*
 360          * Now search the rest of the groups.  We assume that 
 361          * i and gdp correctly point to the last group visited.
 362          */
 363         for (k = 0; k < sb->u.ext2_sb.s_groups_count; k++) {
 364                 i++;
 365                 if (i >= sb->u.ext2_sb.s_groups_count)
 366                         i = 0;
 367                 gdp = get_group_desc (sb, i, &bh2);
 368                 if (gdp->bg_free_blocks_count > 0)
 369                         break;
 370         }
 371         if (k >= sb->u.ext2_sb.s_groups_count) {
 372                 unlock_super (sb);
 373                 return 0;
 374         }
 375         bitmap_nr = load_block_bitmap (sb, i);
 376         bh = sb->u.ext2_sb.s_block_bitmap[bitmap_nr];
 377         r = memscan(bh->b_data, 0, EXT2_BLOCKS_PER_GROUP(sb) >> 3);
 378         j = (r - bh->b_data) << 3;
 379         if (j < EXT2_BLOCKS_PER_GROUP(sb))
 380                 goto search_back;
 381         else
 382                 j = find_first_zero_bit ((unsigned long *) bh->b_data,
 383                                          EXT2_BLOCKS_PER_GROUP(sb));
 384         if (j >= EXT2_BLOCKS_PER_GROUP(sb)) {
 385                 ext2_error (sb, "ext2_new_block",
 386                             "Free blocks count corrupted for block group %d", i);
 387                 unlock_super (sb);
 388                 return 0;
 389         }
 390 
 391 search_back:
 392         /* 
 393          * We have succeeded in finding a free byte in the block
 394          * bitmap.  Now search backwards up to 7 bits to find the
 395          * start of this group of free blocks.
 396          */
 397         for (k = 0; k < 7 && j > 0 && !test_bit (j - 1, bh->b_data); k++, j--);
 398         
 399 got_block:
 400 
 401         ext2_debug ("using block group %d(%d)\n", i, gdp->bg_free_blocks_count);
 402 
 403         tmp = j + i * EXT2_BLOCKS_PER_GROUP(sb) + es->s_first_data_block;
 404 
 405         if (test_opt (sb, CHECK_STRICT) &&
 406             (tmp == gdp->bg_block_bitmap ||
 407              tmp == gdp->bg_inode_bitmap ||
 408              in_range (tmp, gdp->bg_inode_table, sb->u.ext2_sb.s_itb_per_group)))
 409                 ext2_panic (sb, "ext2_new_block",
 410                             "Allocating block in system zone - "
 411                             "block = %u", tmp);
 412 
 413         if (set_bit (j, bh->b_data)) {
 414                 ext2_warning (sb, "ext2_new_block",
 415                               "bit already set for block %d", j);
 416                 goto repeat;
 417         }
 418 
 419         ext2_debug ("found bit %d\n", j);
 420 
 421         /*
 422          * Do block preallocation now if required.
 423          */
 424 #ifdef EXT2_PREALLOCATE
 425         if (prealloc_block) {
 426                 *prealloc_count = 0;
 427                 *prealloc_block = tmp + 1;
 428                 for (k = 1;
 429                      k < 8 && (j + k) < EXT2_BLOCKS_PER_GROUP(sb); k++) {
 430                         if (set_bit (j + k, bh->b_data))
 431                                 break;
 432                         (*prealloc_count)++;
 433                 }       
 434                 gdp->bg_free_blocks_count -= *prealloc_count;
 435                 es->s_free_blocks_count -= *prealloc_count;
 436                 ext2_debug ("Preallocated a further %lu bits.\n",
 437                             *prealloc_count);
 438         }
 439 #endif
 440 
 441         j = tmp;
 442 
 443         mark_buffer_dirty(bh, 1);
 444         if (sb->s_flags & MS_SYNCHRONOUS) {
 445                 ll_rw_block (WRITE, 1, &bh);
 446                 wait_on_buffer (bh);
 447         }
 448 
 449         if (j >= es->s_blocks_count) {
 450                 ext2_error (sb, "ext2_new_block",
 451                             "block >= blocks count - "
 452                             "block_group = %d, block=%d", i, j);
 453                 unlock_super (sb);
 454                 return 0;
 455         }
 456         if (!(bh = getblk (sb->s_dev, j, sb->s_blocksize))) {
 457                 ext2_error (sb, "ext2_new_block", "cannot get block %d", j);
 458                 unlock_super (sb);
 459                 return 0;
 460         }
 461         memset(bh->b_data, 0, sb->s_blocksize);
 462         bh->b_uptodate = 1;
 463         mark_buffer_dirty(bh, 1);
 464         brelse (bh);
 465 
 466         ext2_debug ("allocating block %d. "
 467                     "Goal hits %d of %d.\n", j, goal_hits, goal_attempts);
 468 
 469         gdp->bg_free_blocks_count--;
 470         mark_buffer_dirty(bh2, 1);
 471         es->s_free_blocks_count--;
 472         mark_buffer_dirty(sb->u.ext2_sb.s_sbh, 1);
 473         sb->s_dirt = 1;
 474         unlock_super (sb);
 475         return j;
 476 }
 477 
 478 unsigned long ext2_count_free_blocks (struct super_block * sb)
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 479 {
 480 #ifdef EXT2FS_DEBUG
 481         struct ext2_super_block * es;
 482         unsigned long desc_count, bitmap_count, x;
 483         int bitmap_nr;
 484         struct ext2_group_desc * gdp;
 485         int i;
 486         
 487         lock_super (sb);
 488         es = sb->u.ext2_sb.s_es;
 489         desc_count = 0;
 490         bitmap_count = 0;
 491         gdp = NULL;
 492         for (i = 0; i < sb->u.ext2_sb.s_groups_count; i++) {
 493                 gdp = get_group_desc (sb, i, NULL);
 494                 desc_count += gdp->bg_free_blocks_count;
 495                 bitmap_nr = load_block_bitmap (sb, i);
 496                 x = ext2_count_free (sb->u.ext2_sb.s_block_bitmap[bitmap_nr],
 497                                      sb->s_blocksize);
 498                 printk ("group %d: stored = %d, counted = %lu\n",
 499                         i, gdp->bg_free_blocks_count, x);
 500                 bitmap_count += x;
 501         }
 502         printk("ext2_count_free_blocks: stored = %lu, computed = %lu, %lu\n",
 503                es->s_free_blocks_count, desc_count, bitmap_count);
 504         unlock_super (sb);
 505         return bitmap_count;
 506 #else
 507         return sb->u.ext2_sb.s_es->s_free_blocks_count;
 508 #endif
 509 }
 510 
 511 static inline int block_in_use (unsigned long block,
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 512                                 struct super_block * sb,
 513                                 unsigned char * map)
 514 {
 515         return test_bit ((block - sb->u.ext2_sb.s_es->s_first_data_block) %
 516                          EXT2_BLOCKS_PER_GROUP(sb), map);
 517 }
 518 
 519 void ext2_check_blocks_bitmap (struct super_block * sb)
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 520 {
 521         struct buffer_head * bh;
 522         struct ext2_super_block * es;
 523         unsigned long desc_count, bitmap_count, x;
 524         unsigned long desc_blocks;
 525         int bitmap_nr;
 526         struct ext2_group_desc * gdp;
 527         int i, j;
 528 
 529         lock_super (sb);
 530         es = sb->u.ext2_sb.s_es;
 531         desc_count = 0;
 532         bitmap_count = 0;
 533         gdp = NULL;
 534         desc_blocks = (sb->u.ext2_sb.s_groups_count + EXT2_DESC_PER_BLOCK(sb) - 1) /
 535                       EXT2_DESC_PER_BLOCK(sb);
 536         for (i = 0; i < sb->u.ext2_sb.s_groups_count; i++) {
 537                 gdp = get_group_desc (sb, i, NULL);
 538                 desc_count += gdp->bg_free_blocks_count;
 539                 bitmap_nr = load_block_bitmap (sb, i);
 540                 bh = sb->u.ext2_sb.s_block_bitmap[bitmap_nr];
 541 
 542                 if (!test_bit (0, bh->b_data))
 543                         ext2_error (sb, "ext2_check_blocks_bitmap",
 544                                     "Superblock in group %d is marked free", i);
 545 
 546                 for (j = 0; j < desc_blocks; j++)
 547                         if (!test_bit (j + 1, bh->b_data))
 548                                 ext2_error (sb, "ext2_check_blocks_bitmap",
 549                                             "Descriptor block #%d in group "
 550                                             "%d is marked free", j, i);
 551 
 552                 if (!block_in_use (gdp->bg_block_bitmap, sb, bh->b_data))
 553                         ext2_error (sb, "ext2_check_blocks_bitmap",
 554                                     "Block bitmap for group %d is marked free",
 555                                     i);
 556 
 557                 if (!block_in_use (gdp->bg_inode_bitmap, sb, bh->b_data))
 558                         ext2_error (sb, "ext2_check_blocks_bitmap",
 559                                     "Inode bitmap for group %d is marked free",
 560                                     i);
 561 
 562                 for (j = 0; j < sb->u.ext2_sb.s_itb_per_group; j++)
 563                         if (!block_in_use (gdp->bg_inode_table + j, sb, bh->b_data))
 564                                 ext2_error (sb, "ext2_check_blocks_bitmap",
 565                                             "Block #%d of the inode table in "
 566                                             "group %d is marked free", j, i);
 567 
 568                 x = ext2_count_free (bh, sb->s_blocksize);
 569                 if (gdp->bg_free_blocks_count != x)
 570                         ext2_error (sb, "ext2_check_blocks_bitmap",
 571                                     "Wrong free blocks count for group %d, "
 572                                     "stored = %d, counted = %lu", i,
 573                                     gdp->bg_free_blocks_count, x);
 574                 bitmap_count += x;
 575         }
 576         if (es->s_free_blocks_count != bitmap_count)
 577                 ext2_error (sb, "ext2_check_blocks_bitmap",
 578                             "Wrong free blocks count in super block, "
 579                             "stored = %lu, counted = %lu",
 580                             es->s_free_blocks_count, bitmap_count);
 581         unlock_super (sb);
 582 }

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