linux/fs/ext3/ialloc.c
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   1/*
   2 *  linux/fs/ext3/ialloc.c
   3 *
   4 * Copyright (C) 1992, 1993, 1994, 1995
   5 * Remy Card (card@masi.ibp.fr)
   6 * Laboratoire MASI - Institut Blaise Pascal
   7 * Universite Pierre et Marie Curie (Paris VI)
   8 *
   9 *  BSD ufs-inspired inode and directory allocation by
  10 *  Stephen Tweedie (sct@redhat.com), 1993
  11 *  Big-endian to little-endian byte-swapping/bitmaps by
  12 *        David S. Miller (davem@caip.rutgers.edu), 1995
  13 */
  14
  15#include <linux/time.h>
  16#include <linux/fs.h>
  17#include <linux/jbd.h>
  18#include <linux/ext3_fs.h>
  19#include <linux/ext3_jbd.h>
  20#include <linux/stat.h>
  21#include <linux/string.h>
  22#include <linux/quotaops.h>
  23#include <linux/buffer_head.h>
  24#include <linux/random.h>
  25#include <linux/bitops.h>
  26
  27#include <asm/byteorder.h>
  28
  29#include "xattr.h"
  30#include "acl.h"
  31
  32/*
  33 * ialloc.c contains the inodes allocation and deallocation routines
  34 */
  35
  36/*
  37 * The free inodes are managed by bitmaps.  A file system contains several
  38 * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
  39 * block for inodes, N blocks for the inode table and data blocks.
  40 *
  41 * The file system contains group descriptors which are located after the
  42 * super block.  Each descriptor contains the number of the bitmap block and
  43 * the free blocks count in the block.
  44 */
  45
  46
  47/*
  48 * Read the inode allocation bitmap for a given block_group, reading
  49 * into the specified slot in the superblock's bitmap cache.
  50 *
  51 * Return buffer_head of bitmap on success or NULL.
  52 */
  53static struct buffer_head *
  54read_inode_bitmap(struct super_block * sb, unsigned long block_group)
  55{
  56        struct ext3_group_desc *desc;
  57        struct buffer_head *bh = NULL;
  58
  59        desc = ext3_get_group_desc(sb, block_group, NULL);
  60        if (!desc)
  61                goto error_out;
  62
  63        bh = sb_bread(sb, le32_to_cpu(desc->bg_inode_bitmap));
  64        if (!bh)
  65                ext3_error(sb, "read_inode_bitmap",
  66                            "Cannot read inode bitmap - "
  67                            "block_group = %lu, inode_bitmap = %u",
  68                            block_group, le32_to_cpu(desc->bg_inode_bitmap));
  69error_out:
  70        return bh;
  71}
  72
  73/*
  74 * NOTE! When we get the inode, we're the only people
  75 * that have access to it, and as such there are no
  76 * race conditions we have to worry about. The inode
  77 * is not on the hash-lists, and it cannot be reached
  78 * through the filesystem because the directory entry
  79 * has been deleted earlier.
  80 *
  81 * HOWEVER: we must make sure that we get no aliases,
  82 * which means that we have to call "clear_inode()"
  83 * _before_ we mark the inode not in use in the inode
  84 * bitmaps. Otherwise a newly created file might use
  85 * the same inode number (not actually the same pointer
  86 * though), and then we'd have two inodes sharing the
  87 * same inode number and space on the harddisk.
  88 */
  89void ext3_free_inode (handle_t *handle, struct inode * inode)
  90{
  91        struct super_block * sb = inode->i_sb;
  92        int is_directory;
  93        unsigned long ino;
  94        struct buffer_head *bitmap_bh = NULL;
  95        struct buffer_head *bh2;
  96        unsigned long block_group;
  97        unsigned long bit;
  98        struct ext3_group_desc * gdp;
  99        struct ext3_super_block * es;
 100        struct ext3_sb_info *sbi;
 101        int fatal = 0, err;
 102
 103        if (atomic_read(&inode->i_count) > 1) {
 104                printk ("ext3_free_inode: inode has count=%d\n",
 105                                        atomic_read(&inode->i_count));
 106                return;
 107        }
 108        if (inode->i_nlink) {
 109                printk ("ext3_free_inode: inode has nlink=%d\n",
 110                        inode->i_nlink);
 111                return;
 112        }
 113        if (!sb) {
 114                printk("ext3_free_inode: inode on nonexistent device\n");
 115                return;
 116        }
 117        sbi = EXT3_SB(sb);
 118
 119        ino = inode->i_ino;
 120        ext3_debug ("freeing inode %lu\n", ino);
 121
 122        is_directory = S_ISDIR(inode->i_mode);
 123
 124        es = EXT3_SB(sb)->s_es;
 125        if (ino < EXT3_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
 126                ext3_error (sb, "ext3_free_inode",
 127                            "reserved or nonexistent inode %lu", ino);
 128                goto error_return;
 129        }
 130        block_group = (ino - 1) / EXT3_INODES_PER_GROUP(sb);
 131        bit = (ino - 1) % EXT3_INODES_PER_GROUP(sb);
 132        bitmap_bh = read_inode_bitmap(sb, block_group);
 133        if (!bitmap_bh)
 134                goto error_return;
 135
 136        BUFFER_TRACE(bitmap_bh, "get_write_access");
 137        fatal = ext3_journal_get_write_access(handle, bitmap_bh);
 138        if (fatal)
 139                goto error_return;
 140
 141        /* Ok, now we can actually update the inode bitmaps.. */
 142        if (!ext3_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
 143                                        bit, bitmap_bh->b_data))
 144                ext3_error (sb, "ext3_free_inode",
 145                              "bit already cleared for inode %lu", ino);
 146        else {
 147                gdp = ext3_get_group_desc (sb, block_group, &bh2);
 148
 149                BUFFER_TRACE(bh2, "get_write_access");
 150                fatal = ext3_journal_get_write_access(handle, bh2);
 151                if (fatal) goto error_return;
 152
 153                if (gdp) {
 154                        spin_lock(sb_bgl_lock(sbi, block_group));
 155                        le16_add_cpu(&gdp->bg_free_inodes_count, 1);
 156                        if (is_directory)
 157                                le16_add_cpu(&gdp->bg_used_dirs_count, -1);
 158                        spin_unlock(sb_bgl_lock(sbi, block_group));
 159                        percpu_counter_inc(&sbi->s_freeinodes_counter);
 160                        if (is_directory)
 161                                percpu_counter_dec(&sbi->s_dirs_counter);
 162
 163                }
 164                BUFFER_TRACE(bh2, "call ext3_journal_dirty_metadata");
 165                err = ext3_journal_dirty_metadata(handle, bh2);
 166                if (!fatal) fatal = err;
 167        }
 168        BUFFER_TRACE(bitmap_bh, "call ext3_journal_dirty_metadata");
 169        err = ext3_journal_dirty_metadata(handle, bitmap_bh);
 170        if (!fatal)
 171                fatal = err;
 172
 173error_return:
 174        brelse(bitmap_bh);
 175        ext3_std_error(sb, fatal);
 176}
 177
 178/*
 179 * There are two policies for allocating an inode.  If the new inode is
 180 * a directory, then a forward search is made for a block group with both
 181 * free space and a low directory-to-inode ratio; if that fails, then of
 182 * the groups with above-average free space, that group with the fewest
 183 * directories already is chosen.
 184 *
 185 * For other inodes, search forward from the parent directory\'s block
 186 * group to find a free inode.
 187 */
 188static int find_group_dir(struct super_block *sb, struct inode *parent)
 189{
 190        int ngroups = EXT3_SB(sb)->s_groups_count;
 191        unsigned int freei, avefreei;
 192        struct ext3_group_desc *desc, *best_desc = NULL;
 193        int group, best_group = -1;
 194
 195        freei = percpu_counter_read_positive(&EXT3_SB(sb)->s_freeinodes_counter);
 196        avefreei = freei / ngroups;
 197
 198        for (group = 0; group < ngroups; group++) {
 199                desc = ext3_get_group_desc (sb, group, NULL);
 200                if (!desc || !desc->bg_free_inodes_count)
 201                        continue;
 202                if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
 203                        continue;
 204                if (!best_desc ||
 205                    (le16_to_cpu(desc->bg_free_blocks_count) >
 206                     le16_to_cpu(best_desc->bg_free_blocks_count))) {
 207                        best_group = group;
 208                        best_desc = desc;
 209                }
 210        }
 211        return best_group;
 212}
 213
 214/*
 215 * Orlov's allocator for directories.
 216 *
 217 * We always try to spread first-level directories.
 218 *
 219 * If there are blockgroups with both free inodes and free blocks counts
 220 * not worse than average we return one with smallest directory count.
 221 * Otherwise we simply return a random group.
 222 *
 223 * For the rest rules look so:
 224 *
 225 * It's OK to put directory into a group unless
 226 * it has too many directories already (max_dirs) or
 227 * it has too few free inodes left (min_inodes) or
 228 * it has too few free blocks left (min_blocks) or
 229 * it's already running too large debt (max_debt).
 230 * Parent's group is preferred, if it doesn't satisfy these
 231 * conditions we search cyclically through the rest. If none
 232 * of the groups look good we just look for a group with more
 233 * free inodes than average (starting at parent's group).
 234 *
 235 * Debt is incremented each time we allocate a directory and decremented
 236 * when we allocate an inode, within 0--255.
 237 */
 238
 239#define INODE_COST 64
 240#define BLOCK_COST 256
 241
 242static int find_group_orlov(struct super_block *sb, struct inode *parent)
 243{
 244        int parent_group = EXT3_I(parent)->i_block_group;
 245        struct ext3_sb_info *sbi = EXT3_SB(sb);
 246        struct ext3_super_block *es = sbi->s_es;
 247        int ngroups = sbi->s_groups_count;
 248        int inodes_per_group = EXT3_INODES_PER_GROUP(sb);
 249        unsigned int freei, avefreei;
 250        ext3_fsblk_t freeb, avefreeb;
 251        ext3_fsblk_t blocks_per_dir;
 252        unsigned int ndirs;
 253        int max_debt, max_dirs, min_inodes;
 254        ext3_grpblk_t min_blocks;
 255        int group = -1, i;
 256        struct ext3_group_desc *desc;
 257
 258        freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
 259        avefreei = freei / ngroups;
 260        freeb = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
 261        avefreeb = freeb / ngroups;
 262        ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
 263
 264        if ((parent == sb->s_root->d_inode) ||
 265            (EXT3_I(parent)->i_flags & EXT3_TOPDIR_FL)) {
 266                int best_ndir = inodes_per_group;
 267                int best_group = -1;
 268
 269                get_random_bytes(&group, sizeof(group));
 270                parent_group = (unsigned)group % ngroups;
 271                for (i = 0; i < ngroups; i++) {
 272                        group = (parent_group + i) % ngroups;
 273                        desc = ext3_get_group_desc (sb, group, NULL);
 274                        if (!desc || !desc->bg_free_inodes_count)
 275                                continue;
 276                        if (le16_to_cpu(desc->bg_used_dirs_count) >= best_ndir)
 277                                continue;
 278                        if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
 279                                continue;
 280                        if (le16_to_cpu(desc->bg_free_blocks_count) < avefreeb)
 281                                continue;
 282                        best_group = group;
 283                        best_ndir = le16_to_cpu(desc->bg_used_dirs_count);
 284                }
 285                if (best_group >= 0)
 286                        return best_group;
 287                goto fallback;
 288        }
 289
 290        blocks_per_dir = (le32_to_cpu(es->s_blocks_count) - freeb) / ndirs;
 291
 292        max_dirs = ndirs / ngroups + inodes_per_group / 16;
 293        min_inodes = avefreei - inodes_per_group / 4;
 294        min_blocks = avefreeb - EXT3_BLOCKS_PER_GROUP(sb) / 4;
 295
 296        max_debt = EXT3_BLOCKS_PER_GROUP(sb) / max(blocks_per_dir, (ext3_fsblk_t)BLOCK_COST);
 297        if (max_debt * INODE_COST > inodes_per_group)
 298                max_debt = inodes_per_group / INODE_COST;
 299        if (max_debt > 255)
 300                max_debt = 255;
 301        if (max_debt == 0)
 302                max_debt = 1;
 303
 304        for (i = 0; i < ngroups; i++) {
 305                group = (parent_group + i) % ngroups;
 306                desc = ext3_get_group_desc (sb, group, NULL);
 307                if (!desc || !desc->bg_free_inodes_count)
 308                        continue;
 309                if (le16_to_cpu(desc->bg_used_dirs_count) >= max_dirs)
 310                        continue;
 311                if (le16_to_cpu(desc->bg_free_inodes_count) < min_inodes)
 312                        continue;
 313                if (le16_to_cpu(desc->bg_free_blocks_count) < min_blocks)
 314                        continue;
 315                return group;
 316        }
 317
 318fallback:
 319        for (i = 0; i < ngroups; i++) {
 320                group = (parent_group + i) % ngroups;
 321                desc = ext3_get_group_desc (sb, group, NULL);
 322                if (!desc || !desc->bg_free_inodes_count)
 323                        continue;
 324                if (le16_to_cpu(desc->bg_free_inodes_count) >= avefreei)
 325                        return group;
 326        }
 327
 328        if (avefreei) {
 329                /*
 330                 * The free-inodes counter is approximate, and for really small
 331                 * filesystems the above test can fail to find any blockgroups
 332                 */
 333                avefreei = 0;
 334                goto fallback;
 335        }
 336
 337        return -1;
 338}
 339
 340static int find_group_other(struct super_block *sb, struct inode *parent)
 341{
 342        int parent_group = EXT3_I(parent)->i_block_group;
 343        int ngroups = EXT3_SB(sb)->s_groups_count;
 344        struct ext3_group_desc *desc;
 345        int group, i;
 346
 347        /*
 348         * Try to place the inode in its parent directory
 349         */
 350        group = parent_group;
 351        desc = ext3_get_group_desc (sb, group, NULL);
 352        if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
 353                        le16_to_cpu(desc->bg_free_blocks_count))
 354                return group;
 355
 356        /*
 357         * We're going to place this inode in a different blockgroup from its
 358         * parent.  We want to cause files in a common directory to all land in
 359         * the same blockgroup.  But we want files which are in a different
 360         * directory which shares a blockgroup with our parent to land in a
 361         * different blockgroup.
 362         *
 363         * So add our directory's i_ino into the starting point for the hash.
 364         */
 365        group = (group + parent->i_ino) % ngroups;
 366
 367        /*
 368         * Use a quadratic hash to find a group with a free inode and some free
 369         * blocks.
 370         */
 371        for (i = 1; i < ngroups; i <<= 1) {
 372                group += i;
 373                if (group >= ngroups)
 374                        group -= ngroups;
 375                desc = ext3_get_group_desc (sb, group, NULL);
 376                if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
 377                                le16_to_cpu(desc->bg_free_blocks_count))
 378                        return group;
 379        }
 380
 381        /*
 382         * That failed: try linear search for a free inode, even if that group
 383         * has no free blocks.
 384         */
 385        group = parent_group;
 386        for (i = 0; i < ngroups; i++) {
 387                if (++group >= ngroups)
 388                        group = 0;
 389                desc = ext3_get_group_desc (sb, group, NULL);
 390                if (desc && le16_to_cpu(desc->bg_free_inodes_count))
 391                        return group;
 392        }
 393
 394        return -1;
 395}
 396
 397/*
 398 * There are two policies for allocating an inode.  If the new inode is
 399 * a directory, then a forward search is made for a block group with both
 400 * free space and a low directory-to-inode ratio; if that fails, then of
 401 * the groups with above-average free space, that group with the fewest
 402 * directories already is chosen.
 403 *
 404 * For other inodes, search forward from the parent directory's block
 405 * group to find a free inode.
 406 */
 407struct inode *ext3_new_inode(handle_t *handle, struct inode * dir,
 408                             const struct qstr *qstr, int mode)
 409{
 410        struct super_block *sb;
 411        struct buffer_head *bitmap_bh = NULL;
 412        struct buffer_head *bh2;
 413        int group;
 414        unsigned long ino = 0;
 415        struct inode * inode;
 416        struct ext3_group_desc * gdp = NULL;
 417        struct ext3_super_block * es;
 418        struct ext3_inode_info *ei;
 419        struct ext3_sb_info *sbi;
 420        int err = 0;
 421        struct inode *ret;
 422        int i;
 423
 424        /* Cannot create files in a deleted directory */
 425        if (!dir || !dir->i_nlink)
 426                return ERR_PTR(-EPERM);
 427
 428        sb = dir->i_sb;
 429        inode = new_inode(sb);
 430        if (!inode)
 431                return ERR_PTR(-ENOMEM);
 432        ei = EXT3_I(inode);
 433
 434        sbi = EXT3_SB(sb);
 435        es = sbi->s_es;
 436        if (S_ISDIR(mode)) {
 437                if (test_opt (sb, OLDALLOC))
 438                        group = find_group_dir(sb, dir);
 439                else
 440                        group = find_group_orlov(sb, dir);
 441        } else
 442                group = find_group_other(sb, dir);
 443
 444        err = -ENOSPC;
 445        if (group == -1)
 446                goto out;
 447
 448        for (i = 0; i < sbi->s_groups_count; i++) {
 449                err = -EIO;
 450
 451                gdp = ext3_get_group_desc(sb, group, &bh2);
 452                if (!gdp)
 453                        goto fail;
 454
 455                brelse(bitmap_bh);
 456                bitmap_bh = read_inode_bitmap(sb, group);
 457                if (!bitmap_bh)
 458                        goto fail;
 459
 460                ino = 0;
 461
 462repeat_in_this_group:
 463                ino = ext3_find_next_zero_bit((unsigned long *)
 464                                bitmap_bh->b_data, EXT3_INODES_PER_GROUP(sb), ino);
 465                if (ino < EXT3_INODES_PER_GROUP(sb)) {
 466
 467                        BUFFER_TRACE(bitmap_bh, "get_write_access");
 468                        err = ext3_journal_get_write_access(handle, bitmap_bh);
 469                        if (err)
 470                                goto fail;
 471
 472                        if (!ext3_set_bit_atomic(sb_bgl_lock(sbi, group),
 473                                                ino, bitmap_bh->b_data)) {
 474                                /* we won it */
 475                                BUFFER_TRACE(bitmap_bh,
 476                                        "call ext3_journal_dirty_metadata");
 477                                err = ext3_journal_dirty_metadata(handle,
 478                                                                bitmap_bh);
 479                                if (err)
 480                                        goto fail;
 481                                goto got;
 482                        }
 483                        /* we lost it */
 484                        journal_release_buffer(handle, bitmap_bh);
 485
 486                        if (++ino < EXT3_INODES_PER_GROUP(sb))
 487                                goto repeat_in_this_group;
 488                }
 489
 490                /*
 491                 * This case is possible in concurrent environment.  It is very
 492                 * rare.  We cannot repeat the find_group_xxx() call because
 493                 * that will simply return the same blockgroup, because the
 494                 * group descriptor metadata has not yet been updated.
 495                 * So we just go onto the next blockgroup.
 496                 */
 497                if (++group == sbi->s_groups_count)
 498                        group = 0;
 499        }
 500        err = -ENOSPC;
 501        goto out;
 502
 503got:
 504        ino += group * EXT3_INODES_PER_GROUP(sb) + 1;
 505        if (ino < EXT3_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
 506                ext3_error (sb, "ext3_new_inode",
 507                            "reserved inode or inode > inodes count - "
 508                            "block_group = %d, inode=%lu", group, ino);
 509                err = -EIO;
 510                goto fail;
 511        }
 512
 513        BUFFER_TRACE(bh2, "get_write_access");
 514        err = ext3_journal_get_write_access(handle, bh2);
 515        if (err) goto fail;
 516        spin_lock(sb_bgl_lock(sbi, group));
 517        le16_add_cpu(&gdp->bg_free_inodes_count, -1);
 518        if (S_ISDIR(mode)) {
 519                le16_add_cpu(&gdp->bg_used_dirs_count, 1);
 520        }
 521        spin_unlock(sb_bgl_lock(sbi, group));
 522        BUFFER_TRACE(bh2, "call ext3_journal_dirty_metadata");
 523        err = ext3_journal_dirty_metadata(handle, bh2);
 524        if (err) goto fail;
 525
 526        percpu_counter_dec(&sbi->s_freeinodes_counter);
 527        if (S_ISDIR(mode))
 528                percpu_counter_inc(&sbi->s_dirs_counter);
 529
 530
 531        if (test_opt(sb, GRPID)) {
 532                inode->i_mode = mode;
 533                inode->i_uid = current_fsuid();
 534                inode->i_gid = dir->i_gid;
 535        } else
 536                inode_init_owner(inode, dir, mode);
 537
 538        inode->i_ino = ino;
 539        /* This is the optimal IO size (for stat), not the fs block size */
 540        inode->i_blocks = 0;
 541        inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
 542
 543        memset(ei->i_data, 0, sizeof(ei->i_data));
 544        ei->i_dir_start_lookup = 0;
 545        ei->i_disksize = 0;
 546
 547        ei->i_flags =
 548                ext3_mask_flags(mode, EXT3_I(dir)->i_flags & EXT3_FL_INHERITED);
 549#ifdef EXT3_FRAGMENTS
 550        ei->i_faddr = 0;
 551        ei->i_frag_no = 0;
 552        ei->i_frag_size = 0;
 553#endif
 554        ei->i_file_acl = 0;
 555        ei->i_dir_acl = 0;
 556        ei->i_dtime = 0;
 557        ei->i_block_alloc_info = NULL;
 558        ei->i_block_group = group;
 559
 560        ext3_set_inode_flags(inode);
 561        if (IS_DIRSYNC(inode))
 562                handle->h_sync = 1;
 563        if (insert_inode_locked(inode) < 0) {
 564                err = -EINVAL;
 565                goto fail_drop;
 566        }
 567        spin_lock(&sbi->s_next_gen_lock);
 568        inode->i_generation = sbi->s_next_generation++;
 569        spin_unlock(&sbi->s_next_gen_lock);
 570
 571        ei->i_state_flags = 0;
 572        ext3_set_inode_state(inode, EXT3_STATE_NEW);
 573
 574        /* See comment in ext3_iget for explanation */
 575        if (ino >= EXT3_FIRST_INO(sb) + 1 &&
 576            EXT3_INODE_SIZE(sb) > EXT3_GOOD_OLD_INODE_SIZE) {
 577                ei->i_extra_isize =
 578                        sizeof(struct ext3_inode) - EXT3_GOOD_OLD_INODE_SIZE;
 579        } else {
 580                ei->i_extra_isize = 0;
 581        }
 582
 583        ret = inode;
 584        dquot_initialize(inode);
 585        err = dquot_alloc_inode(inode);
 586        if (err)
 587                goto fail_drop;
 588
 589        err = ext3_init_acl(handle, inode, dir);
 590        if (err)
 591                goto fail_free_drop;
 592
 593        err = ext3_init_security(handle, inode, dir, qstr);
 594        if (err)
 595                goto fail_free_drop;
 596
 597        err = ext3_mark_inode_dirty(handle, inode);
 598        if (err) {
 599                ext3_std_error(sb, err);
 600                goto fail_free_drop;
 601        }
 602
 603        ext3_debug("allocating inode %lu\n", inode->i_ino);
 604        goto really_out;
 605fail:
 606        ext3_std_error(sb, err);
 607out:
 608        iput(inode);
 609        ret = ERR_PTR(err);
 610really_out:
 611        brelse(bitmap_bh);
 612        return ret;
 613
 614fail_free_drop:
 615        dquot_free_inode(inode);
 616
 617fail_drop:
 618        dquot_drop(inode);
 619        inode->i_flags |= S_NOQUOTA;
 620        inode->i_nlink = 0;
 621        unlock_new_inode(inode);
 622        iput(inode);
 623        brelse(bitmap_bh);
 624        return ERR_PTR(err);
 625}
 626
 627/* Verify that we are loading a valid orphan from disk */
 628struct inode *ext3_orphan_get(struct super_block *sb, unsigned long ino)
 629{
 630        unsigned long max_ino = le32_to_cpu(EXT3_SB(sb)->s_es->s_inodes_count);
 631        unsigned long block_group;
 632        int bit;
 633        struct buffer_head *bitmap_bh;
 634        struct inode *inode = NULL;
 635        long err = -EIO;
 636
 637        /* Error cases - e2fsck has already cleaned up for us */
 638        if (ino > max_ino) {
 639                ext3_warning(sb, __func__,
 640                             "bad orphan ino %lu!  e2fsck was run?", ino);
 641                goto error;
 642        }
 643
 644        block_group = (ino - 1) / EXT3_INODES_PER_GROUP(sb);
 645        bit = (ino - 1) % EXT3_INODES_PER_GROUP(sb);
 646        bitmap_bh = read_inode_bitmap(sb, block_group);
 647        if (!bitmap_bh) {
 648                ext3_warning(sb, __func__,
 649                             "inode bitmap error for orphan %lu", ino);
 650                goto error;
 651        }
 652
 653        /* Having the inode bit set should be a 100% indicator that this
 654         * is a valid orphan (no e2fsck run on fs).  Orphans also include
 655         * inodes that were being truncated, so we can't check i_nlink==0.
 656         */
 657        if (!ext3_test_bit(bit, bitmap_bh->b_data))
 658                goto bad_orphan;
 659
 660        inode = ext3_iget(sb, ino);
 661        if (IS_ERR(inode))
 662                goto iget_failed;
 663
 664        /*
 665         * If the orphans has i_nlinks > 0 then it should be able to be
 666         * truncated, otherwise it won't be removed from the orphan list
 667         * during processing and an infinite loop will result.
 668         */
 669        if (inode->i_nlink && !ext3_can_truncate(inode))
 670                goto bad_orphan;
 671
 672        if (NEXT_ORPHAN(inode) > max_ino)
 673                goto bad_orphan;
 674        brelse(bitmap_bh);
 675        return inode;
 676
 677iget_failed:
 678        err = PTR_ERR(inode);
 679        inode = NULL;
 680bad_orphan:
 681        ext3_warning(sb, __func__,
 682                     "bad orphan inode %lu!  e2fsck was run?", ino);
 683        printk(KERN_NOTICE "ext3_test_bit(bit=%d, block=%llu) = %d\n",
 684               bit, (unsigned long long)bitmap_bh->b_blocknr,
 685               ext3_test_bit(bit, bitmap_bh->b_data));
 686        printk(KERN_NOTICE "inode=%p\n", inode);
 687        if (inode) {
 688                printk(KERN_NOTICE "is_bad_inode(inode)=%d\n",
 689                       is_bad_inode(inode));
 690                printk(KERN_NOTICE "NEXT_ORPHAN(inode)=%u\n",
 691                       NEXT_ORPHAN(inode));
 692                printk(KERN_NOTICE "max_ino=%lu\n", max_ino);
 693                printk(KERN_NOTICE "i_nlink=%u\n", inode->i_nlink);
 694                /* Avoid freeing blocks if we got a bad deleted inode */
 695                if (inode->i_nlink == 0)
 696                        inode->i_blocks = 0;
 697                iput(inode);
 698        }
 699        brelse(bitmap_bh);
 700error:
 701        return ERR_PTR(err);
 702}
 703
 704unsigned long ext3_count_free_inodes (struct super_block * sb)
 705{
 706        unsigned long desc_count;
 707        struct ext3_group_desc *gdp;
 708        int i;
 709#ifdef EXT3FS_DEBUG
 710        struct ext3_super_block *es;
 711        unsigned long bitmap_count, x;
 712        struct buffer_head *bitmap_bh = NULL;
 713
 714        es = EXT3_SB(sb)->s_es;
 715        desc_count = 0;
 716        bitmap_count = 0;
 717        gdp = NULL;
 718        for (i = 0; i < EXT3_SB(sb)->s_groups_count; i++) {
 719                gdp = ext3_get_group_desc (sb, i, NULL);
 720                if (!gdp)
 721                        continue;
 722                desc_count += le16_to_cpu(gdp->bg_free_inodes_count);
 723                brelse(bitmap_bh);
 724                bitmap_bh = read_inode_bitmap(sb, i);
 725                if (!bitmap_bh)
 726                        continue;
 727
 728                x = ext3_count_free(bitmap_bh, EXT3_INODES_PER_GROUP(sb) / 8);
 729                printk("group %d: stored = %d, counted = %lu\n",
 730                        i, le16_to_cpu(gdp->bg_free_inodes_count), x);
 731                bitmap_count += x;
 732        }
 733        brelse(bitmap_bh);
 734        printk("ext3_count_free_inodes: stored = %u, computed = %lu, %lu\n",
 735                le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
 736        return desc_count;
 737#else
 738        desc_count = 0;
 739        for (i = 0; i < EXT3_SB(sb)->s_groups_count; i++) {
 740                gdp = ext3_get_group_desc (sb, i, NULL);
 741                if (!gdp)
 742                        continue;
 743                desc_count += le16_to_cpu(gdp->bg_free_inodes_count);
 744                cond_resched();
 745        }
 746        return desc_count;
 747#endif
 748}
 749
 750/* Called at mount-time, super-block is locked */
 751unsigned long ext3_count_dirs (struct super_block * sb)
 752{
 753        unsigned long count = 0;
 754        int i;
 755
 756        for (i = 0; i < EXT3_SB(sb)->s_groups_count; i++) {
 757                struct ext3_group_desc *gdp = ext3_get_group_desc (sb, i, NULL);
 758                if (!gdp)
 759                        continue;
 760                count += le16_to_cpu(gdp->bg_used_dirs_count);
 761        }
 762        return count;
 763}
 764
 765