root/fs/ext2/ialloc.c

DEFINITIONS

1. read_inode_bitmap
2. ext2_release_inode
3. ext2_free_inode
4. ext2_preread_inode
5. find_group_dir
6. find_group_orlov
7. find_group_other
8. ext2_new_inode
9. ext2_count_free_inodes
10. ext2_count_dirs

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/fs/ext2/ialloc.c
   4  *
   5  * Copyright (C) 1992, 1993, 1994, 1995
   6  * Remy Card (card@masi.ibp.fr)
   7  * Laboratoire MASI - Institut Blaise Pascal
   8  * Universite Pierre et Marie Curie (Paris VI)
   9  *
  10  *  BSD ufs-inspired inode and directory allocation by 
  11  *  Stephen Tweedie (sct@dcs.ed.ac.uk), 1993
  12  *  Big-endian to little-endian byte-swapping/bitmaps by
  13  *        David S. Miller (davem@caip.rutgers.edu), 1995
  14  */
  15 
  16 #include <linux/quotaops.h>
  17 #include <linux/sched.h>
  18 #include <linux/backing-dev.h>
  19 #include <linux/buffer_head.h>
  20 #include <linux/random.h>
  21 #include "ext2.h"
  22 #include "xattr.h"
  23 #include "acl.h"
  24 
  25 /*
  26  * ialloc.c contains the inodes allocation and deallocation routines
  27  */
  28 
  29 /*
  30  * The free inodes are managed by bitmaps.  A file system contains several
  31  * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
  32  * block for inodes, N blocks for the inode table and data blocks.
  33  *
  34  * The file system contains group descriptors which are located after the
  35  * super block.  Each descriptor contains the number of the bitmap block and
  36  * the free blocks count in the block.
  37  */
  38 
  39 
  40 /*
  41  * Read the inode allocation bitmap for a given block_group, reading
  42  * into the specified slot in the superblock's bitmap cache.
  43  *
  44  * Return buffer_head of bitmap on success or NULL.
  45  */
  46 static struct buffer_head *
  47 read_inode_bitmap(struct super_block * sb, unsigned long block_group)
  48 {
  49         struct ext2_group_desc *desc;
  50         struct buffer_head *bh = NULL;
  51 
  52         desc = ext2_get_group_desc(sb, block_group, NULL);
  53         if (!desc)
  54                 goto error_out;
  55 
  56         bh = sb_bread(sb, le32_to_cpu(desc->bg_inode_bitmap));
  57         if (!bh)
  58                 ext2_error(sb, "read_inode_bitmap",
  59                             "Cannot read inode bitmap - "
  60                             "block_group = %lu, inode_bitmap = %u",
  61                             block_group, le32_to_cpu(desc->bg_inode_bitmap));
  62 error_out:
  63         return bh;
  64 }
  65 
  66 static void ext2_release_inode(struct super_block *sb, int group, int dir)
  67 {
  68         struct ext2_group_desc * desc;
  69         struct buffer_head *bh;
  70 
  71         desc = ext2_get_group_desc(sb, group, &bh);
  72         if (!desc) {
  73                 ext2_error(sb, "ext2_release_inode",
  74                         "can't get descriptor for group %d", group);
  75                 return;
  76         }
  77 
  78         spin_lock(sb_bgl_lock(EXT2_SB(sb), group));
  79         le16_add_cpu(&desc->bg_free_inodes_count, 1);
  80         if (dir)
  81                 le16_add_cpu(&desc->bg_used_dirs_count, -1);
  82         spin_unlock(sb_bgl_lock(EXT2_SB(sb), group));
  83         if (dir)
  84                 percpu_counter_dec(&EXT2_SB(sb)->s_dirs_counter);
  85         mark_buffer_dirty(bh);
  86 }
  87 
  88 /*
  89  * NOTE! When we get the inode, we're the only people
  90  * that have access to it, and as such there are no
  91  * race conditions we have to worry about. The inode
  92  * is not on the hash-lists, and it cannot be reached
  93  * through the filesystem because the directory entry
  94  * has been deleted earlier.
  95  *
  96  * HOWEVER: we must make sure that we get no aliases,
  97  * which means that we have to call "clear_inode()"
  98  * _before_ we mark the inode not in use in the inode
  99  * bitmaps. Otherwise a newly created file might use
 100  * the same inode number (not actually the same pointer
 101  * though), and then we'd have two inodes sharing the
 102  * same inode number and space on the harddisk.
 103  */
 104 void ext2_free_inode (struct inode * inode)
 105 {
 106         struct super_block * sb = inode->i_sb;
 107         int is_directory;
 108         unsigned long ino;
 109         struct buffer_head *bitmap_bh;
 110         unsigned long block_group;
 111         unsigned long bit;
 112         struct ext2_super_block * es;
 113 
 114         ino = inode->i_ino;
 115         ext2_debug ("freeing inode %lu\n", ino);
 116 
 117         /*
 118          * Note: we must free any quota before locking the superblock,
 119          * as writing the quota to disk may need the lock as well.
 120          */
 121         /* Quota is already initialized in iput() */
 122         dquot_free_inode(inode);
 123         dquot_drop(inode);
 124 
 125         es = EXT2_SB(sb)->s_es;
 126         is_directory = S_ISDIR(inode->i_mode);
 127 
 128         if (ino < EXT2_FIRST_INO(sb) ||
 129             ino > le32_to_cpu(es->s_inodes_count)) {
 130                 ext2_error (sb, "ext2_free_inode",
 131                             "reserved or nonexistent inode %lu", ino);
 132                 return;
 133         }
 134         block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
 135         bit = (ino - 1) % EXT2_INODES_PER_GROUP(sb);
 136         bitmap_bh = read_inode_bitmap(sb, block_group);
 137         if (!bitmap_bh)
 138                 return;
 139 
 140         /* Ok, now we can actually update the inode bitmaps.. */
 141         if (!ext2_clear_bit_atomic(sb_bgl_lock(EXT2_SB(sb), block_group),
 142                                 bit, (void *) bitmap_bh->b_data))
 143                 ext2_error (sb, "ext2_free_inode",
 144                               "bit already cleared for inode %lu", ino);
 145         else
 146                 ext2_release_inode(sb, block_group, is_directory);
 147         mark_buffer_dirty(bitmap_bh);
 148         if (sb->s_flags & SB_SYNCHRONOUS)
 149                 sync_dirty_buffer(bitmap_bh);
 150 
 151         brelse(bitmap_bh);
 152 }
 153 
 154 /*
 155  * We perform asynchronous prereading of the new inode's inode block when
 156  * we create the inode, in the expectation that the inode will be written
 157  * back soon.  There are two reasons:
 158  *
 159  * - When creating a large number of files, the async prereads will be
 160  *   nicely merged into large reads
 161  * - When writing out a large number of inodes, we don't need to keep on
 162  *   stalling the writes while we read the inode block.
 163  *
 164  * FIXME: ext2_get_group_desc() needs to be simplified.
 165  */
 166 static void ext2_preread_inode(struct inode *inode)
 167 {
 168         unsigned long block_group;
 169         unsigned long offset;
 170         unsigned long block;
 171         struct ext2_group_desc * gdp;
 172         struct backing_dev_info *bdi;
 173 
 174         bdi = inode_to_bdi(inode);
 175         if (bdi_rw_congested(bdi))
 176                 return;
 177 
 178         block_group = (inode->i_ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
 179         gdp = ext2_get_group_desc(inode->i_sb, block_group, NULL);
 180         if (gdp == NULL)
 181                 return;
 182 
 183         /*
 184          * Figure out the offset within the block group inode table
 185          */
 186         offset = ((inode->i_ino - 1) % EXT2_INODES_PER_GROUP(inode->i_sb)) *
 187                                 EXT2_INODE_SIZE(inode->i_sb);
 188         block = le32_to_cpu(gdp->bg_inode_table) +
 189                                 (offset >> EXT2_BLOCK_SIZE_BITS(inode->i_sb));
 190         sb_breadahead(inode->i_sb, block);
 191 }
 192 
 193 /*
 194  * There are two policies for allocating an inode.  If the new inode is
 195  * a directory, then a forward search is made for a block group with both
 196  * free space and a low directory-to-inode ratio; if that fails, then of
 197  * the groups with above-average free space, that group with the fewest
 198  * directories already is chosen.
 199  *
 200  * For other inodes, search forward from the parent directory\'s block
 201  * group to find a free inode.
 202  */
 203 static int find_group_dir(struct super_block *sb, struct inode *parent)
 204 {
 205         int ngroups = EXT2_SB(sb)->s_groups_count;
 206         int avefreei = ext2_count_free_inodes(sb) / ngroups;
 207         struct ext2_group_desc *desc, *best_desc = NULL;
 208         int group, best_group = -1;
 209 
 210         for (group = 0; group < ngroups; group++) {
 211                 desc = ext2_get_group_desc (sb, group, NULL);
 212                 if (!desc || !desc->bg_free_inodes_count)
 213                         continue;
 214                 if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
 215                         continue;
 216                 if (!best_desc || 
 217                     (le16_to_cpu(desc->bg_free_blocks_count) >
 218                      le16_to_cpu(best_desc->bg_free_blocks_count))) {
 219                         best_group = group;
 220                         best_desc = desc;
 221                 }
 222         }
 223 
 224         return best_group;
 225 }
 226 
 227 /* 
 228  * Orlov's allocator for directories. 
 229  * 
 230  * We always try to spread first-level directories.
 231  *
 232  * If there are blockgroups with both free inodes and free blocks counts 
 233  * not worse than average we return one with smallest directory count. 
 234  * Otherwise we simply return a random group. 
 235  * 
 236  * For the rest rules look so: 
 237  * 
 238  * It's OK to put directory into a group unless 
 239  * it has too many directories already (max_dirs) or 
 240  * it has too few free inodes left (min_inodes) or 
 241  * it has too few free blocks left (min_blocks) or 
 242  * it's already running too large debt (max_debt). 
 243  * Parent's group is preferred, if it doesn't satisfy these 
 244  * conditions we search cyclically through the rest. If none 
 245  * of the groups look good we just look for a group with more 
 246  * free inodes than average (starting at parent's group). 
 247  * 
 248  * Debt is incremented each time we allocate a directory and decremented 
 249  * when we allocate an inode, within 0--255. 
 250  */ 
 251 
 252 #define INODE_COST 64
 253 #define BLOCK_COST 256
 254 
 255 static int find_group_orlov(struct super_block *sb, struct inode *parent)
 256 {
 257         int parent_group = EXT2_I(parent)->i_block_group;
 258         struct ext2_sb_info *sbi = EXT2_SB(sb);
 259         struct ext2_super_block *es = sbi->s_es;
 260         int ngroups = sbi->s_groups_count;
 261         int inodes_per_group = EXT2_INODES_PER_GROUP(sb);
 262         int freei;
 263         int avefreei;
 264         int free_blocks;
 265         int avefreeb;
 266         int blocks_per_dir;
 267         int ndirs;
 268         int max_debt, max_dirs, min_blocks, min_inodes;
 269         int group = -1, i;
 270         struct ext2_group_desc *desc;
 271 
 272         freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
 273         avefreei = freei / ngroups;
 274         free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
 275         avefreeb = free_blocks / ngroups;
 276         ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
 277 
 278         if ((parent == d_inode(sb->s_root)) ||
 279             (EXT2_I(parent)->i_flags & EXT2_TOPDIR_FL)) {
 280                 struct ext2_group_desc *best_desc = NULL;
 281                 int best_ndir = inodes_per_group;
 282                 int best_group = -1;
 283 
 284                 group = prandom_u32();
 285                 parent_group = (unsigned)group % ngroups;
 286                 for (i = 0; i < ngroups; i++) {
 287                         group = (parent_group + i) % ngroups;
 288                         desc = ext2_get_group_desc (sb, group, NULL);
 289                         if (!desc || !desc->bg_free_inodes_count)
 290                                 continue;
 291                         if (le16_to_cpu(desc->bg_used_dirs_count) >= best_ndir)
 292                                 continue;
 293                         if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
 294                                 continue;
 295                         if (le16_to_cpu(desc->bg_free_blocks_count) < avefreeb)
 296                                 continue;
 297                         best_group = group;
 298                         best_ndir = le16_to_cpu(desc->bg_used_dirs_count);
 299                         best_desc = desc;
 300                 }
 301                 if (best_group >= 0) {
 302                         desc = best_desc;
 303                         group = best_group;
 304                         goto found;
 305                 }
 306                 goto fallback;
 307         }
 308 
 309         if (ndirs == 0)
 310                 ndirs = 1;      /* percpu_counters are approximate... */
 311 
 312         blocks_per_dir = (le32_to_cpu(es->s_blocks_count)-free_blocks) / ndirs;
 313 
 314         max_dirs = ndirs / ngroups + inodes_per_group / 16;
 315         min_inodes = avefreei - inodes_per_group / 4;
 316         min_blocks = avefreeb - EXT2_BLOCKS_PER_GROUP(sb) / 4;
 317 
 318         max_debt = EXT2_BLOCKS_PER_GROUP(sb) / max(blocks_per_dir, BLOCK_COST);
 319         if (max_debt * INODE_COST > inodes_per_group)
 320                 max_debt = inodes_per_group / INODE_COST;
 321         if (max_debt > 255)
 322                 max_debt = 255;
 323         if (max_debt == 0)
 324                 max_debt = 1;
 325 
 326         for (i = 0; i < ngroups; i++) {
 327                 group = (parent_group + i) % ngroups;
 328                 desc = ext2_get_group_desc (sb, group, NULL);
 329                 if (!desc || !desc->bg_free_inodes_count)
 330                         continue;
 331                 if (sbi->s_debts[group] >= max_debt)
 332                         continue;
 333                 if (le16_to_cpu(desc->bg_used_dirs_count) >= max_dirs)
 334                         continue;
 335                 if (le16_to_cpu(desc->bg_free_inodes_count) < min_inodes)
 336                         continue;
 337                 if (le16_to_cpu(desc->bg_free_blocks_count) < min_blocks)
 338                         continue;
 339                 goto found;
 340         }
 341 
 342 fallback:
 343         for (i = 0; i < ngroups; i++) {
 344                 group = (parent_group + i) % ngroups;
 345                 desc = ext2_get_group_desc (sb, group, NULL);
 346                 if (!desc || !desc->bg_free_inodes_count)
 347                         continue;
 348                 if (le16_to_cpu(desc->bg_free_inodes_count) >= avefreei)
 349                         goto found;
 350         }
 351 
 352         if (avefreei) {
 353                 /*
 354                  * The free-inodes counter is approximate, and for really small
 355                  * filesystems the above test can fail to find any blockgroups
 356                  */
 357                 avefreei = 0;
 358                 goto fallback;
 359         }
 360 
 361         return -1;
 362 
 363 found:
 364         return group;
 365 }
 366 
 367 static int find_group_other(struct super_block *sb, struct inode *parent)
 368 {
 369         int parent_group = EXT2_I(parent)->i_block_group;
 370         int ngroups = EXT2_SB(sb)->s_groups_count;
 371         struct ext2_group_desc *desc;
 372         int group, i;
 373 
 374         /*
 375          * Try to place the inode in its parent directory
 376          */
 377         group = parent_group;
 378         desc = ext2_get_group_desc (sb, group, NULL);
 379         if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
 380                         le16_to_cpu(desc->bg_free_blocks_count))
 381                 goto found;
 382 
 383         /*
 384          * We're going to place this inode in a different blockgroup from its
 385          * parent.  We want to cause files in a common directory to all land in
 386          * the same blockgroup.  But we want files which are in a different
 387          * directory which shares a blockgroup with our parent to land in a
 388          * different blockgroup.
 389          *
 390          * So add our directory's i_ino into the starting point for the hash.
 391          */
 392         group = (group + parent->i_ino) % ngroups;
 393 
 394         /*
 395          * Use a quadratic hash to find a group with a free inode and some
 396          * free blocks.
 397          */
 398         for (i = 1; i < ngroups; i <<= 1) {
 399                 group += i;
 400                 if (group >= ngroups)
 401                         group -= ngroups;
 402                 desc = ext2_get_group_desc (sb, group, NULL);
 403                 if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
 404                                 le16_to_cpu(desc->bg_free_blocks_count))
 405                         goto found;
 406         }
 407 
 408         /*
 409          * That failed: try linear search for a free inode, even if that group
 410          * has no free blocks.
 411          */
 412         group = parent_group;
 413         for (i = 0; i < ngroups; i++) {
 414                 if (++group >= ngroups)
 415                         group = 0;
 416                 desc = ext2_get_group_desc (sb, group, NULL);
 417                 if (desc && le16_to_cpu(desc->bg_free_inodes_count))
 418                         goto found;
 419         }
 420 
 421         return -1;
 422 
 423 found:
 424         return group;
 425 }
 426 
 427 struct inode *ext2_new_inode(struct inode *dir, umode_t mode,
 428                              const struct qstr *qstr)
 429 {
 430         struct super_block *sb;
 431         struct buffer_head *bitmap_bh = NULL;
 432         struct buffer_head *bh2;
 433         int group, i;
 434         ino_t ino = 0;
 435         struct inode * inode;
 436         struct ext2_group_desc *gdp;
 437         struct ext2_super_block *es;
 438         struct ext2_inode_info *ei;
 439         struct ext2_sb_info *sbi;
 440         int err;
 441 
 442         sb = dir->i_sb;
 443         inode = new_inode(sb);
 444         if (!inode)
 445                 return ERR_PTR(-ENOMEM);
 446 
 447         ei = EXT2_I(inode);
 448         sbi = EXT2_SB(sb);
 449         es = sbi->s_es;
 450         if (S_ISDIR(mode)) {
 451                 if (test_opt(sb, OLDALLOC))
 452                         group = find_group_dir(sb, dir);
 453                 else
 454                         group = find_group_orlov(sb, dir);
 455         } else 
 456                 group = find_group_other(sb, dir);
 457 
 458         if (group == -1) {
 459                 err = -ENOSPC;
 460                 goto fail;
 461         }
 462 
 463         for (i = 0; i < sbi->s_groups_count; i++) {
 464                 gdp = ext2_get_group_desc(sb, group, &bh2);
 465                 if (!gdp) {
 466                         if (++group == sbi->s_groups_count)
 467                                 group = 0;
 468                         continue;
 469                 }
 470                 brelse(bitmap_bh);
 471                 bitmap_bh = read_inode_bitmap(sb, group);
 472                 if (!bitmap_bh) {
 473                         err = -EIO;
 474                         goto fail;
 475                 }
 476                 ino = 0;
 477 
 478 repeat_in_this_group:
 479                 ino = ext2_find_next_zero_bit((unsigned long *)bitmap_bh->b_data,
 480                                               EXT2_INODES_PER_GROUP(sb), ino);
 481                 if (ino >= EXT2_INODES_PER_GROUP(sb)) {
 482                         /*
 483                          * Rare race: find_group_xx() decided that there were
 484                          * free inodes in this group, but by the time we tried
 485                          * to allocate one, they're all gone.  This can also
 486                          * occur because the counters which find_group_orlov()
 487                          * uses are approximate.  So just go and search the
 488                          * next block group.
 489                          */
 490                         if (++group == sbi->s_groups_count)
 491                                 group = 0;
 492                         continue;
 493                 }
 494                 if (ext2_set_bit_atomic(sb_bgl_lock(sbi, group),
 495                                                 ino, bitmap_bh->b_data)) {
 496                         /* we lost this inode */
 497                         if (++ino >= EXT2_INODES_PER_GROUP(sb)) {
 498                                 /* this group is exhausted, try next group */
 499                                 if (++group == sbi->s_groups_count)
 500                                         group = 0;
 501                                 continue;
 502                         }
 503                         /* try to find free inode in the same group */
 504                         goto repeat_in_this_group;
 505                 }
 506                 goto got;
 507         }
 508 
 509         /*
 510          * Scanned all blockgroups.
 511          */
 512         brelse(bitmap_bh);
 513         err = -ENOSPC;
 514         goto fail;
 515 got:
 516         mark_buffer_dirty(bitmap_bh);
 517         if (sb->s_flags & SB_SYNCHRONOUS)
 518                 sync_dirty_buffer(bitmap_bh);
 519         brelse(bitmap_bh);
 520 
 521         ino += group * EXT2_INODES_PER_GROUP(sb) + 1;
 522         if (ino < EXT2_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
 523                 ext2_error (sb, "ext2_new_inode",
 524                             "reserved inode or inode > inodes count - "
 525                             "block_group = %d,inode=%lu", group,
 526                             (unsigned long) ino);
 527                 err = -EIO;
 528                 goto fail;
 529         }
 530 
 531         percpu_counter_add(&sbi->s_freeinodes_counter, -1);
 532         if (S_ISDIR(mode))
 533                 percpu_counter_inc(&sbi->s_dirs_counter);
 534 
 535         spin_lock(sb_bgl_lock(sbi, group));
 536         le16_add_cpu(&gdp->bg_free_inodes_count, -1);
 537         if (S_ISDIR(mode)) {
 538                 if (sbi->s_debts[group] < 255)
 539                         sbi->s_debts[group]++;
 540                 le16_add_cpu(&gdp->bg_used_dirs_count, 1);
 541         } else {
 542                 if (sbi->s_debts[group])
 543                         sbi->s_debts[group]--;
 544         }
 545         spin_unlock(sb_bgl_lock(sbi, group));
 546 
 547         mark_buffer_dirty(bh2);
 548         if (test_opt(sb, GRPID)) {
 549                 inode->i_mode = mode;
 550                 inode->i_uid = current_fsuid();
 551                 inode->i_gid = dir->i_gid;
 552         } else
 553                 inode_init_owner(inode, dir, mode);
 554 
 555         inode->i_ino = ino;
 556         inode->i_blocks = 0;
 557         inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
 558         memset(ei->i_data, 0, sizeof(ei->i_data));
 559         ei->i_flags =
 560                 ext2_mask_flags(mode, EXT2_I(dir)->i_flags & EXT2_FL_INHERITED);
 561         ei->i_faddr = 0;
 562         ei->i_frag_no = 0;
 563         ei->i_frag_size = 0;
 564         ei->i_file_acl = 0;
 565         ei->i_dir_acl = 0;
 566         ei->i_dtime = 0;
 567         ei->i_block_alloc_info = NULL;
 568         ei->i_block_group = group;
 569         ei->i_dir_start_lookup = 0;
 570         ei->i_state = EXT2_STATE_NEW;
 571         ext2_set_inode_flags(inode);
 572         spin_lock(&sbi->s_next_gen_lock);
 573         inode->i_generation = sbi->s_next_generation++;
 574         spin_unlock(&sbi->s_next_gen_lock);
 575         if (insert_inode_locked(inode) < 0) {
 576                 ext2_error(sb, "ext2_new_inode",
 577                            "inode number already in use - inode=%lu",
 578                            (unsigned long) ino);
 579                 err = -EIO;
 580                 goto fail;
 581         }
 582 
 583         err = dquot_initialize(inode);
 584         if (err)
 585                 goto fail_drop;
 586 
 587         err = dquot_alloc_inode(inode);
 588         if (err)
 589                 goto fail_drop;
 590 
 591         err = ext2_init_acl(inode, dir);
 592         if (err)
 593                 goto fail_free_drop;
 594 
 595         err = ext2_init_security(inode, dir, qstr);
 596         if (err)
 597                 goto fail_free_drop;
 598 
 599         mark_inode_dirty(inode);
 600         ext2_debug("allocating inode %lu\n", inode->i_ino);
 601         ext2_preread_inode(inode);
 602         return inode;
 603 
 604 fail_free_drop:
 605         dquot_free_inode(inode);
 606 
 607 fail_drop:
 608         dquot_drop(inode);
 609         inode->i_flags |= S_NOQUOTA;
 610         clear_nlink(inode);
 611         discard_new_inode(inode);
 612         return ERR_PTR(err);
 613 
 614 fail:
 615         make_bad_inode(inode);
 616         iput(inode);
 617         return ERR_PTR(err);
 618 }
 619 
 620 unsigned long ext2_count_free_inodes (struct super_block * sb)
 621 {
 622         struct ext2_group_desc *desc;
 623         unsigned long desc_count = 0;
 624         int i;  
 625 
 626 #ifdef EXT2FS_DEBUG
 627         struct ext2_super_block *es;
 628         unsigned long bitmap_count = 0;
 629         struct buffer_head *bitmap_bh = NULL;
 630 
 631         es = EXT2_SB(sb)->s_es;
 632         for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) {
 633                 unsigned x;
 634 
 635                 desc = ext2_get_group_desc (sb, i, NULL);
 636                 if (!desc)
 637                         continue;
 638                 desc_count += le16_to_cpu(desc->bg_free_inodes_count);
 639                 brelse(bitmap_bh);
 640                 bitmap_bh = read_inode_bitmap(sb, i);
 641                 if (!bitmap_bh)
 642                         continue;
 643 
 644                 x = ext2_count_free(bitmap_bh, EXT2_INODES_PER_GROUP(sb) / 8);
 645                 printk("group %d: stored = %d, counted = %u\n",
 646                         i, le16_to_cpu(desc->bg_free_inodes_count), x);
 647                 bitmap_count += x;
 648         }
 649         brelse(bitmap_bh);
 650         printk("ext2_count_free_inodes: stored = %lu, computed = %lu, %lu\n",
 651                 (unsigned long)
 652                 percpu_counter_read(&EXT2_SB(sb)->s_freeinodes_counter),
 653                 desc_count, bitmap_count);
 654         return desc_count;
 655 #else
 656         for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) {
 657                 desc = ext2_get_group_desc (sb, i, NULL);
 658                 if (!desc)
 659                         continue;
 660                 desc_count += le16_to_cpu(desc->bg_free_inodes_count);
 661         }
 662         return desc_count;
 663 #endif
 664 }
 665 
 666 /* Called at mount-time, super-block is locked */
 667 unsigned long ext2_count_dirs (struct super_block * sb)
 668 {
 669         unsigned long count = 0;
 670         int i;
 671 
 672         for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) {
 673                 struct ext2_group_desc *gdp = ext2_get_group_desc (sb, i, NULL);
 674                 if (!gdp)
 675                         continue;
 676                 count += le16_to_cpu(gdp->bg_used_dirs_count);
 677         }
 678         return count;
 679 }
 680