linux/fs/ext4/ialloc.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 *  linux/fs/ext4/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@redhat.com), 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/time.h>
  17#include <linux/fs.h>
  18#include <linux/stat.h>
  19#include <linux/string.h>
  20#include <linux/quotaops.h>
  21#include <linux/buffer_head.h>
  22#include <linux/random.h>
  23#include <linux/bitops.h>
  24#include <linux/blkdev.h>
  25#include <linux/cred.h>
  26
  27#include <asm/byteorder.h>
  28
  29#include "ext4.h"
  30#include "ext4_jbd2.h"
  31#include "xattr.h"
  32#include "acl.h"
  33
  34#include <trace/events/ext4.h>
  35
  36/*
  37 * ialloc.c contains the inodes allocation and deallocation routines
  38 */
  39
  40/*
  41 * The free inodes are managed by bitmaps.  A file system contains several
  42 * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
  43 * block for inodes, N blocks for the inode table and data blocks.
  44 *
  45 * The file system contains group descriptors which are located after the
  46 * super block.  Each descriptor contains the number of the bitmap block and
  47 * the free blocks count in the block.
  48 */
  49
  50/*
  51 * To avoid calling the atomic setbit hundreds or thousands of times, we only
  52 * need to use it within a single byte (to ensure we get endianness right).
  53 * We can use memset for the rest of the bitmap as there are no other users.
  54 */
  55void ext4_mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
  56{
  57        int i;
  58
  59        if (start_bit >= end_bit)
  60                return;
  61
  62        ext4_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
  63        for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
  64                ext4_set_bit(i, bitmap);
  65        if (i < end_bit)
  66                memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
  67}
  68
  69void ext4_end_bitmap_read(struct buffer_head *bh, int uptodate)
  70{
  71        if (uptodate) {
  72                set_buffer_uptodate(bh);
  73                set_bitmap_uptodate(bh);
  74        }
  75        unlock_buffer(bh);
  76        put_bh(bh);
  77}
  78
  79static int ext4_validate_inode_bitmap(struct super_block *sb,
  80                                      struct ext4_group_desc *desc,
  81                                      ext4_group_t block_group,
  82                                      struct buffer_head *bh)
  83{
  84        ext4_fsblk_t    blk;
  85        struct ext4_group_info *grp = ext4_get_group_info(sb, block_group);
  86
  87        if (buffer_verified(bh))
  88                return 0;
  89        if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp))
  90                return -EFSCORRUPTED;
  91
  92        ext4_lock_group(sb, block_group);
  93        if (buffer_verified(bh))
  94                goto verified;
  95        blk = ext4_inode_bitmap(sb, desc);
  96        if (!ext4_inode_bitmap_csum_verify(sb, block_group, desc, bh,
  97                                           EXT4_INODES_PER_GROUP(sb) / 8)) {
  98                ext4_unlock_group(sb, block_group);
  99                ext4_error(sb, "Corrupt inode bitmap - block_group = %u, "
 100                           "inode_bitmap = %llu", block_group, blk);
 101                ext4_mark_group_bitmap_corrupted(sb, block_group,
 102                                        EXT4_GROUP_INFO_IBITMAP_CORRUPT);
 103                return -EFSBADCRC;
 104        }
 105        set_buffer_verified(bh);
 106verified:
 107        ext4_unlock_group(sb, block_group);
 108        return 0;
 109}
 110
 111/*
 112 * Read the inode allocation bitmap for a given block_group, reading
 113 * into the specified slot in the superblock's bitmap cache.
 114 *
 115 * Return buffer_head of bitmap on success or NULL.
 116 */
 117static struct buffer_head *
 118ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
 119{
 120        struct ext4_group_desc *desc;
 121        struct ext4_sb_info *sbi = EXT4_SB(sb);
 122        struct buffer_head *bh = NULL;
 123        ext4_fsblk_t bitmap_blk;
 124        int err;
 125
 126        desc = ext4_get_group_desc(sb, block_group, NULL);
 127        if (!desc)
 128                return ERR_PTR(-EFSCORRUPTED);
 129
 130        bitmap_blk = ext4_inode_bitmap(sb, desc);
 131        if ((bitmap_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) ||
 132            (bitmap_blk >= ext4_blocks_count(sbi->s_es))) {
 133                ext4_error(sb, "Invalid inode bitmap blk %llu in "
 134                           "block_group %u", bitmap_blk, block_group);
 135                ext4_mark_group_bitmap_corrupted(sb, block_group,
 136                                        EXT4_GROUP_INFO_IBITMAP_CORRUPT);
 137                return ERR_PTR(-EFSCORRUPTED);
 138        }
 139        bh = sb_getblk(sb, bitmap_blk);
 140        if (unlikely(!bh)) {
 141                ext4_warning(sb, "Cannot read inode bitmap - "
 142                             "block_group = %u, inode_bitmap = %llu",
 143                             block_group, bitmap_blk);
 144                return ERR_PTR(-ENOMEM);
 145        }
 146        if (bitmap_uptodate(bh))
 147                goto verify;
 148
 149        lock_buffer(bh);
 150        if (bitmap_uptodate(bh)) {
 151                unlock_buffer(bh);
 152                goto verify;
 153        }
 154
 155        ext4_lock_group(sb, block_group);
 156        if (ext4_has_group_desc_csum(sb) &&
 157            (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT))) {
 158                if (block_group == 0) {
 159                        ext4_unlock_group(sb, block_group);
 160                        unlock_buffer(bh);
 161                        ext4_error(sb, "Inode bitmap for bg 0 marked "
 162                                   "uninitialized");
 163                        err = -EFSCORRUPTED;
 164                        goto out;
 165                }
 166                memset(bh->b_data, 0, (EXT4_INODES_PER_GROUP(sb) + 7) / 8);
 167                ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
 168                                     sb->s_blocksize * 8, bh->b_data);
 169                set_bitmap_uptodate(bh);
 170                set_buffer_uptodate(bh);
 171                set_buffer_verified(bh);
 172                ext4_unlock_group(sb, block_group);
 173                unlock_buffer(bh);
 174                return bh;
 175        }
 176        ext4_unlock_group(sb, block_group);
 177
 178        if (buffer_uptodate(bh)) {
 179                /*
 180                 * if not uninit if bh is uptodate,
 181                 * bitmap is also uptodate
 182                 */
 183                set_bitmap_uptodate(bh);
 184                unlock_buffer(bh);
 185                goto verify;
 186        }
 187        /*
 188         * submit the buffer_head for reading
 189         */
 190        trace_ext4_load_inode_bitmap(sb, block_group);
 191        bh->b_end_io = ext4_end_bitmap_read;
 192        get_bh(bh);
 193        submit_bh(REQ_OP_READ, REQ_META | REQ_PRIO, bh);
 194        wait_on_buffer(bh);
 195        if (!buffer_uptodate(bh)) {
 196                put_bh(bh);
 197                ext4_error(sb, "Cannot read inode bitmap - "
 198                           "block_group = %u, inode_bitmap = %llu",
 199                           block_group, bitmap_blk);
 200                ext4_mark_group_bitmap_corrupted(sb, block_group,
 201                                EXT4_GROUP_INFO_IBITMAP_CORRUPT);
 202                return ERR_PTR(-EIO);
 203        }
 204
 205verify:
 206        err = ext4_validate_inode_bitmap(sb, desc, block_group, bh);
 207        if (err)
 208                goto out;
 209        return bh;
 210out:
 211        put_bh(bh);
 212        return ERR_PTR(err);
 213}
 214
 215/*
 216 * NOTE! When we get the inode, we're the only people
 217 * that have access to it, and as such there are no
 218 * race conditions we have to worry about. The inode
 219 * is not on the hash-lists, and it cannot be reached
 220 * through the filesystem because the directory entry
 221 * has been deleted earlier.
 222 *
 223 * HOWEVER: we must make sure that we get no aliases,
 224 * which means that we have to call "clear_inode()"
 225 * _before_ we mark the inode not in use in the inode
 226 * bitmaps. Otherwise a newly created file might use
 227 * the same inode number (not actually the same pointer
 228 * though), and then we'd have two inodes sharing the
 229 * same inode number and space on the harddisk.
 230 */
 231void ext4_free_inode(handle_t *handle, struct inode *inode)
 232{
 233        struct super_block *sb = inode->i_sb;
 234        int is_directory;
 235        unsigned long ino;
 236        struct buffer_head *bitmap_bh = NULL;
 237        struct buffer_head *bh2;
 238        ext4_group_t block_group;
 239        unsigned long bit;
 240        struct ext4_group_desc *gdp;
 241        struct ext4_super_block *es;
 242        struct ext4_sb_info *sbi;
 243        int fatal = 0, err, count, cleared;
 244        struct ext4_group_info *grp;
 245
 246        if (!sb) {
 247                printk(KERN_ERR "EXT4-fs: %s:%d: inode on "
 248                       "nonexistent device\n", __func__, __LINE__);
 249                return;
 250        }
 251        if (atomic_read(&inode->i_count) > 1) {
 252                ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: count=%d",
 253                         __func__, __LINE__, inode->i_ino,
 254                         atomic_read(&inode->i_count));
 255                return;
 256        }
 257        if (inode->i_nlink) {
 258                ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: nlink=%d\n",
 259                         __func__, __LINE__, inode->i_ino, inode->i_nlink);
 260                return;
 261        }
 262        sbi = EXT4_SB(sb);
 263
 264        ino = inode->i_ino;
 265        ext4_debug("freeing inode %lu\n", ino);
 266        trace_ext4_free_inode(inode);
 267
 268        /*
 269         * Note: we must free any quota before locking the superblock,
 270         * as writing the quota to disk may need the lock as well.
 271         */
 272        dquot_initialize(inode);
 273        dquot_free_inode(inode);
 274        dquot_drop(inode);
 275
 276        is_directory = S_ISDIR(inode->i_mode);
 277
 278        /* Do this BEFORE marking the inode not in use or returning an error */
 279        ext4_clear_inode(inode);
 280
 281        es = sbi->s_es;
 282        if (ino < EXT4_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
 283                ext4_error(sb, "reserved or nonexistent inode %lu", ino);
 284                goto error_return;
 285        }
 286        block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
 287        bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
 288        bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
 289        /* Don't bother if the inode bitmap is corrupt. */
 290        grp = ext4_get_group_info(sb, block_group);
 291        if (IS_ERR(bitmap_bh)) {
 292                fatal = PTR_ERR(bitmap_bh);
 293                bitmap_bh = NULL;
 294                goto error_return;
 295        }
 296        if (unlikely(EXT4_MB_GRP_IBITMAP_CORRUPT(grp))) {
 297                fatal = -EFSCORRUPTED;
 298                goto error_return;
 299        }
 300
 301        BUFFER_TRACE(bitmap_bh, "get_write_access");
 302        fatal = ext4_journal_get_write_access(handle, bitmap_bh);
 303        if (fatal)
 304                goto error_return;
 305
 306        fatal = -ESRCH;
 307        gdp = ext4_get_group_desc(sb, block_group, &bh2);
 308        if (gdp) {
 309                BUFFER_TRACE(bh2, "get_write_access");
 310                fatal = ext4_journal_get_write_access(handle, bh2);
 311        }
 312        ext4_lock_group(sb, block_group);
 313        cleared = ext4_test_and_clear_bit(bit, bitmap_bh->b_data);
 314        if (fatal || !cleared) {
 315                ext4_unlock_group(sb, block_group);
 316                goto out;
 317        }
 318
 319        count = ext4_free_inodes_count(sb, gdp) + 1;
 320        ext4_free_inodes_set(sb, gdp, count);
 321        if (is_directory) {
 322                count = ext4_used_dirs_count(sb, gdp) - 1;
 323                ext4_used_dirs_set(sb, gdp, count);
 324                percpu_counter_dec(&sbi->s_dirs_counter);
 325        }
 326        ext4_inode_bitmap_csum_set(sb, block_group, gdp, bitmap_bh,
 327                                   EXT4_INODES_PER_GROUP(sb) / 8);
 328        ext4_group_desc_csum_set(sb, block_group, gdp);
 329        ext4_unlock_group(sb, block_group);
 330
 331        percpu_counter_inc(&sbi->s_freeinodes_counter);
 332        if (sbi->s_log_groups_per_flex) {
 333                ext4_group_t f = ext4_flex_group(sbi, block_group);
 334
 335                atomic_inc(&sbi->s_flex_groups[f].free_inodes);
 336                if (is_directory)
 337                        atomic_dec(&sbi->s_flex_groups[f].used_dirs);
 338        }
 339        BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata");
 340        fatal = ext4_handle_dirty_metadata(handle, NULL, bh2);
 341out:
 342        if (cleared) {
 343                BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata");
 344                err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
 345                if (!fatal)
 346                        fatal = err;
 347        } else {
 348                ext4_error(sb, "bit already cleared for inode %lu", ino);
 349                ext4_mark_group_bitmap_corrupted(sb, block_group,
 350                                        EXT4_GROUP_INFO_IBITMAP_CORRUPT);
 351        }
 352
 353error_return:
 354        brelse(bitmap_bh);
 355        ext4_std_error(sb, fatal);
 356}
 357
 358struct orlov_stats {
 359        __u64 free_clusters;
 360        __u32 free_inodes;
 361        __u32 used_dirs;
 362};
 363
 364/*
 365 * Helper function for Orlov's allocator; returns critical information
 366 * for a particular block group or flex_bg.  If flex_size is 1, then g
 367 * is a block group number; otherwise it is flex_bg number.
 368 */
 369static void get_orlov_stats(struct super_block *sb, ext4_group_t g,
 370                            int flex_size, struct orlov_stats *stats)
 371{
 372        struct ext4_group_desc *desc;
 373        struct flex_groups *flex_group = EXT4_SB(sb)->s_flex_groups;
 374
 375        if (flex_size > 1) {
 376                stats->free_inodes = atomic_read(&flex_group[g].free_inodes);
 377                stats->free_clusters = atomic64_read(&flex_group[g].free_clusters);
 378                stats->used_dirs = atomic_read(&flex_group[g].used_dirs);
 379                return;
 380        }
 381
 382        desc = ext4_get_group_desc(sb, g, NULL);
 383        if (desc) {
 384                stats->free_inodes = ext4_free_inodes_count(sb, desc);
 385                stats->free_clusters = ext4_free_group_clusters(sb, desc);
 386                stats->used_dirs = ext4_used_dirs_count(sb, desc);
 387        } else {
 388                stats->free_inodes = 0;
 389                stats->free_clusters = 0;
 390                stats->used_dirs = 0;
 391        }
 392}
 393
 394/*
 395 * Orlov's allocator for directories.
 396 *
 397 * We always try to spread first-level directories.
 398 *
 399 * If there are blockgroups with both free inodes and free blocks counts
 400 * not worse than average we return one with smallest directory count.
 401 * Otherwise we simply return a random group.
 402 *
 403 * For the rest rules look so:
 404 *
 405 * It's OK to put directory into a group unless
 406 * it has too many directories already (max_dirs) or
 407 * it has too few free inodes left (min_inodes) or
 408 * it has too few free blocks left (min_blocks) or
 409 * Parent's group is preferred, if it doesn't satisfy these
 410 * conditions we search cyclically through the rest. If none
 411 * of the groups look good we just look for a group with more
 412 * free inodes than average (starting at parent's group).
 413 */
 414
 415static int find_group_orlov(struct super_block *sb, struct inode *parent,
 416                            ext4_group_t *group, umode_t mode,
 417                            const struct qstr *qstr)
 418{
 419        ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 420        struct ext4_sb_info *sbi = EXT4_SB(sb);
 421        ext4_group_t real_ngroups = ext4_get_groups_count(sb);
 422        int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
 423        unsigned int freei, avefreei, grp_free;
 424        ext4_fsblk_t freeb, avefreec;
 425        unsigned int ndirs;
 426        int max_dirs, min_inodes;
 427        ext4_grpblk_t min_clusters;
 428        ext4_group_t i, grp, g, ngroups;
 429        struct ext4_group_desc *desc;
 430        struct orlov_stats stats;
 431        int flex_size = ext4_flex_bg_size(sbi);
 432        struct dx_hash_info hinfo;
 433
 434        ngroups = real_ngroups;
 435        if (flex_size > 1) {
 436                ngroups = (real_ngroups + flex_size - 1) >>
 437                        sbi->s_log_groups_per_flex;
 438                parent_group >>= sbi->s_log_groups_per_flex;
 439        }
 440
 441        freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
 442        avefreei = freei / ngroups;
 443        freeb = EXT4_C2B(sbi,
 444                percpu_counter_read_positive(&sbi->s_freeclusters_counter));
 445        avefreec = freeb;
 446        do_div(avefreec, ngroups);
 447        ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
 448
 449        if (S_ISDIR(mode) &&
 450            ((parent == d_inode(sb->s_root)) ||
 451             (ext4_test_inode_flag(parent, EXT4_INODE_TOPDIR)))) {
 452                int best_ndir = inodes_per_group;
 453                int ret = -1;
 454
 455                if (qstr) {
 456                        hinfo.hash_version = DX_HASH_HALF_MD4;
 457                        hinfo.seed = sbi->s_hash_seed;
 458                        ext4fs_dirhash(qstr->name, qstr->len, &hinfo);
 459                        grp = hinfo.hash;
 460                } else
 461                        grp = prandom_u32();
 462                parent_group = (unsigned)grp % ngroups;
 463                for (i = 0; i < ngroups; i++) {
 464                        g = (parent_group + i) % ngroups;
 465                        get_orlov_stats(sb, g, flex_size, &stats);
 466                        if (!stats.free_inodes)
 467                                continue;
 468                        if (stats.used_dirs >= best_ndir)
 469                                continue;
 470                        if (stats.free_inodes < avefreei)
 471                                continue;
 472                        if (stats.free_clusters < avefreec)
 473                                continue;
 474                        grp = g;
 475                        ret = 0;
 476                        best_ndir = stats.used_dirs;
 477                }
 478                if (ret)
 479                        goto fallback;
 480        found_flex_bg:
 481                if (flex_size == 1) {
 482                        *group = grp;
 483                        return 0;
 484                }
 485
 486                /*
 487                 * We pack inodes at the beginning of the flexgroup's
 488                 * inode tables.  Block allocation decisions will do
 489                 * something similar, although regular files will
 490                 * start at 2nd block group of the flexgroup.  See
 491                 * ext4_ext_find_goal() and ext4_find_near().
 492                 */
 493                grp *= flex_size;
 494                for (i = 0; i < flex_size; i++) {
 495                        if (grp+i >= real_ngroups)
 496                                break;
 497                        desc = ext4_get_group_desc(sb, grp+i, NULL);
 498                        if (desc && ext4_free_inodes_count(sb, desc)) {
 499                                *group = grp+i;
 500                                return 0;
 501                        }
 502                }
 503                goto fallback;
 504        }
 505
 506        max_dirs = ndirs / ngroups + inodes_per_group / 16;
 507        min_inodes = avefreei - inodes_per_group*flex_size / 4;
 508        if (min_inodes < 1)
 509                min_inodes = 1;
 510        min_clusters = avefreec - EXT4_CLUSTERS_PER_GROUP(sb)*flex_size / 4;
 511
 512        /*
 513         * Start looking in the flex group where we last allocated an
 514         * inode for this parent directory
 515         */
 516        if (EXT4_I(parent)->i_last_alloc_group != ~0) {
 517                parent_group = EXT4_I(parent)->i_last_alloc_group;
 518                if (flex_size > 1)
 519                        parent_group >>= sbi->s_log_groups_per_flex;
 520        }
 521
 522        for (i = 0; i < ngroups; i++) {
 523                grp = (parent_group + i) % ngroups;
 524                get_orlov_stats(sb, grp, flex_size, &stats);
 525                if (stats.used_dirs >= max_dirs)
 526                        continue;
 527                if (stats.free_inodes < min_inodes)
 528                        continue;
 529                if (stats.free_clusters < min_clusters)
 530                        continue;
 531                goto found_flex_bg;
 532        }
 533
 534fallback:
 535        ngroups = real_ngroups;
 536        avefreei = freei / ngroups;
 537fallback_retry:
 538        parent_group = EXT4_I(parent)->i_block_group;
 539        for (i = 0; i < ngroups; i++) {
 540                grp = (parent_group + i) % ngroups;
 541                desc = ext4_get_group_desc(sb, grp, NULL);
 542                if (desc) {
 543                        grp_free = ext4_free_inodes_count(sb, desc);
 544                        if (grp_free && grp_free >= avefreei) {
 545                                *group = grp;
 546                                return 0;
 547                        }
 548                }
 549        }
 550
 551        if (avefreei) {
 552                /*
 553                 * The free-inodes counter is approximate, and for really small
 554                 * filesystems the above test can fail to find any blockgroups
 555                 */
 556                avefreei = 0;
 557                goto fallback_retry;
 558        }
 559
 560        return -1;
 561}
 562
 563static int find_group_other(struct super_block *sb, struct inode *parent,
 564                            ext4_group_t *group, umode_t mode)
 565{
 566        ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
 567        ext4_group_t i, last, ngroups = ext4_get_groups_count(sb);
 568        struct ext4_group_desc *desc;
 569        int flex_size = ext4_flex_bg_size(EXT4_SB(sb));
 570
 571        /*
 572         * Try to place the inode is the same flex group as its
 573         * parent.  If we can't find space, use the Orlov algorithm to
 574         * find another flex group, and store that information in the
 575         * parent directory's inode information so that use that flex
 576         * group for future allocations.
 577         */
 578        if (flex_size > 1) {
 579                int retry = 0;
 580
 581        try_again:
 582                parent_group &= ~(flex_size-1);
 583                last = parent_group + flex_size;
 584                if (last > ngroups)
 585                        last = ngroups;
 586                for  (i = parent_group; i < last; i++) {
 587                        desc = ext4_get_group_desc(sb, i, NULL);
 588                        if (desc && ext4_free_inodes_count(sb, desc)) {
 589                                *group = i;
 590                                return 0;
 591                        }
 592                }
 593                if (!retry && EXT4_I(parent)->i_last_alloc_group != ~0) {
 594                        retry = 1;
 595                        parent_group = EXT4_I(parent)->i_last_alloc_group;
 596                        goto try_again;
 597                }
 598                /*
 599                 * If this didn't work, use the Orlov search algorithm
 600                 * to find a new flex group; we pass in the mode to
 601                 * avoid the topdir algorithms.
 602                 */
 603                *group = parent_group + flex_size;
 604                if (*group > ngroups)
 605                        *group = 0;
 606                return find_group_orlov(sb, parent, group, mode, NULL);
 607        }
 608
 609        /*
 610         * Try to place the inode in its parent directory
 611         */
 612        *group = parent_group;
 613        desc = ext4_get_group_desc(sb, *group, NULL);
 614        if (desc && ext4_free_inodes_count(sb, desc) &&
 615            ext4_free_group_clusters(sb, desc))
 616                return 0;
 617
 618        /*
 619         * We're going to place this inode in a different blockgroup from its
 620         * parent.  We want to cause files in a common directory to all land in
 621         * the same blockgroup.  But we want files which are in a different
 622         * directory which shares a blockgroup with our parent to land in a
 623         * different blockgroup.
 624         *
 625         * So add our directory's i_ino into the starting point for the hash.
 626         */
 627        *group = (*group + parent->i_ino) % ngroups;
 628
 629        /*
 630         * Use a quadratic hash to find a group with a free inode and some free
 631         * blocks.
 632         */
 633        for (i = 1; i < ngroups; i <<= 1) {
 634                *group += i;
 635                if (*group >= ngroups)
 636                        *group -= ngroups;
 637                desc = ext4_get_group_desc(sb, *group, NULL);
 638                if (desc && ext4_free_inodes_count(sb, desc) &&
 639                    ext4_free_group_clusters(sb, desc))
 640                        return 0;
 641        }
 642
 643        /*
 644         * That failed: try linear search for a free inode, even if that group
 645         * has no free blocks.
 646         */
 647        *group = parent_group;
 648        for (i = 0; i < ngroups; i++) {
 649                if (++*group >= ngroups)
 650                        *group = 0;
 651                desc = ext4_get_group_desc(sb, *group, NULL);
 652                if (desc && ext4_free_inodes_count(sb, desc))
 653                        return 0;
 654        }
 655
 656        return -1;
 657}
 658
 659/*
 660 * In no journal mode, if an inode has recently been deleted, we want
 661 * to avoid reusing it until we're reasonably sure the inode table
 662 * block has been written back to disk.  (Yes, these values are
 663 * somewhat arbitrary...)
 664 */
 665#define RECENTCY_MIN    5
 666#define RECENTCY_DIRTY  300
 667
 668static int recently_deleted(struct super_block *sb, ext4_group_t group, int ino)
 669{
 670        struct ext4_group_desc  *gdp;
 671        struct ext4_inode       *raw_inode;
 672        struct buffer_head      *bh;
 673        int inodes_per_block = EXT4_SB(sb)->s_inodes_per_block;
 674        int offset, ret = 0;
 675        int recentcy = RECENTCY_MIN;
 676        u32 dtime, now;
 677
 678        gdp = ext4_get_group_desc(sb, group, NULL);
 679        if (unlikely(!gdp))
 680                return 0;
 681
 682        bh = sb_find_get_block(sb, ext4_inode_table(sb, gdp) +
 683                       (ino / inodes_per_block));
 684        if (!bh || !buffer_uptodate(bh))
 685                /*
 686                 * If the block is not in the buffer cache, then it
 687                 * must have been written out.
 688                 */
 689                goto out;
 690
 691        offset = (ino % inodes_per_block) * EXT4_INODE_SIZE(sb);
 692        raw_inode = (struct ext4_inode *) (bh->b_data + offset);
 693
 694        /* i_dtime is only 32 bits on disk, but we only care about relative
 695         * times in the range of a few minutes (i.e. long enough to sync a
 696         * recently-deleted inode to disk), so using the low 32 bits of the
 697         * clock (a 68 year range) is enough, see time_before32() */
 698        dtime = le32_to_cpu(raw_inode->i_dtime);
 699        now = ktime_get_real_seconds();
 700        if (buffer_dirty(bh))
 701                recentcy += RECENTCY_DIRTY;
 702
 703        if (dtime && time_before32(dtime, now) &&
 704            time_before32(now, dtime + recentcy))
 705                ret = 1;
 706out:
 707        brelse(bh);
 708        return ret;
 709}
 710
 711static int find_inode_bit(struct super_block *sb, ext4_group_t group,
 712                          struct buffer_head *bitmap, unsigned long *ino)
 713{
 714next:
 715        *ino = ext4_find_next_zero_bit((unsigned long *)
 716                                       bitmap->b_data,
 717                                       EXT4_INODES_PER_GROUP(sb), *ino);
 718        if (*ino >= EXT4_INODES_PER_GROUP(sb))
 719                return 0;
 720
 721        if ((EXT4_SB(sb)->s_journal == NULL) &&
 722            recently_deleted(sb, group, *ino)) {
 723                *ino = *ino + 1;
 724                if (*ino < EXT4_INODES_PER_GROUP(sb))
 725                        goto next;
 726                return 0;
 727        }
 728
 729        return 1;
 730}
 731
 732/*
 733 * There are two policies for allocating an inode.  If the new inode is
 734 * a directory, then a forward search is made for a block group with both
 735 * free space and a low directory-to-inode ratio; if that fails, then of
 736 * the groups with above-average free space, that group with the fewest
 737 * directories already is chosen.
 738 *
 739 * For other inodes, search forward from the parent directory's block
 740 * group to find a free inode.
 741 */
 742struct inode *__ext4_new_inode(handle_t *handle, struct inode *dir,
 743                               umode_t mode, const struct qstr *qstr,
 744                               __u32 goal, uid_t *owner, __u32 i_flags,
 745                               int handle_type, unsigned int line_no,
 746                               int nblocks)
 747{
 748        struct super_block *sb;
 749        struct buffer_head *inode_bitmap_bh = NULL;
 750        struct buffer_head *group_desc_bh;
 751        ext4_group_t ngroups, group = 0;
 752        unsigned long ino = 0;
 753        struct inode *inode;
 754        struct ext4_group_desc *gdp = NULL;
 755        struct ext4_inode_info *ei;
 756        struct ext4_sb_info *sbi;
 757        int ret2, err;
 758        struct inode *ret;
 759        ext4_group_t i;
 760        ext4_group_t flex_group;
 761        struct ext4_group_info *grp;
 762        int encrypt = 0;
 763
 764        /* Cannot create files in a deleted directory */
 765        if (!dir || !dir->i_nlink)
 766                return ERR_PTR(-EPERM);
 767
 768        sb = dir->i_sb;
 769        sbi = EXT4_SB(sb);
 770
 771        if (unlikely(ext4_forced_shutdown(sbi)))
 772                return ERR_PTR(-EIO);
 773
 774        if ((IS_ENCRYPTED(dir) || DUMMY_ENCRYPTION_ENABLED(sbi)) &&
 775            (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)) &&
 776            !(i_flags & EXT4_EA_INODE_FL)) {
 777                err = fscrypt_get_encryption_info(dir);
 778                if (err)
 779                        return ERR_PTR(err);
 780                if (!fscrypt_has_encryption_key(dir))
 781                        return ERR_PTR(-ENOKEY);
 782                encrypt = 1;
 783        }
 784
 785        if (!handle && sbi->s_journal && !(i_flags & EXT4_EA_INODE_FL)) {
 786#ifdef CONFIG_EXT4_FS_POSIX_ACL
 787                struct posix_acl *p = get_acl(dir, ACL_TYPE_DEFAULT);
 788
 789                if (IS_ERR(p))
 790                        return ERR_CAST(p);
 791                if (p) {
 792                        int acl_size = p->a_count * sizeof(ext4_acl_entry);
 793
 794                        nblocks += (S_ISDIR(mode) ? 2 : 1) *
 795                                __ext4_xattr_set_credits(sb, NULL /* inode */,
 796                                        NULL /* block_bh */, acl_size,
 797                                        true /* is_create */);
 798                        posix_acl_release(p);
 799                }
 800#endif
 801
 802#ifdef CONFIG_SECURITY
 803                {
 804                        int num_security_xattrs = 1;
 805
 806#ifdef CONFIG_INTEGRITY
 807                        num_security_xattrs++;
 808#endif
 809                        /*
 810                         * We assume that security xattrs are never
 811                         * more than 1k.  In practice they are under
 812                         * 128 bytes.
 813                         */
 814                        nblocks += num_security_xattrs *
 815                                __ext4_xattr_set_credits(sb, NULL /* inode */,
 816                                        NULL /* block_bh */, 1024,
 817                                        true /* is_create */);
 818                }
 819#endif
 820                if (encrypt)
 821                        nblocks += __ext4_xattr_set_credits(sb,
 822                                        NULL /* inode */, NULL /* block_bh */,
 823                                        FSCRYPT_SET_CONTEXT_MAX_SIZE,
 824                                        true /* is_create */);
 825        }
 826
 827        ngroups = ext4_get_groups_count(sb);
 828        trace_ext4_request_inode(dir, mode);
 829        inode = new_inode(sb);
 830        if (!inode)
 831                return ERR_PTR(-ENOMEM);
 832        ei = EXT4_I(inode);
 833
 834        /*
 835         * Initialize owners and quota early so that we don't have to account
 836         * for quota initialization worst case in standard inode creating
 837         * transaction
 838         */
 839        if (owner) {
 840                inode->i_mode = mode;
 841                i_uid_write(inode, owner[0]);
 842                i_gid_write(inode, owner[1]);
 843        } else if (test_opt(sb, GRPID)) {
 844                inode->i_mode = mode;
 845                inode->i_uid = current_fsuid();
 846                inode->i_gid = dir->i_gid;
 847        } else
 848                inode_init_owner(inode, dir, mode);
 849
 850        if (ext4_has_feature_project(sb) &&
 851            ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT))
 852                ei->i_projid = EXT4_I(dir)->i_projid;
 853        else
 854                ei->i_projid = make_kprojid(&init_user_ns, EXT4_DEF_PROJID);
 855
 856        err = dquot_initialize(inode);
 857        if (err)
 858                goto out;
 859
 860        if (!goal)
 861                goal = sbi->s_inode_goal;
 862
 863        if (goal && goal <= le32_to_cpu(sbi->s_es->s_inodes_count)) {
 864                group = (goal - 1) / EXT4_INODES_PER_GROUP(sb);
 865                ino = (goal - 1) % EXT4_INODES_PER_GROUP(sb);
 866                ret2 = 0;
 867                goto got_group;
 868        }
 869
 870        if (S_ISDIR(mode))
 871                ret2 = find_group_orlov(sb, dir, &group, mode, qstr);
 872        else
 873                ret2 = find_group_other(sb, dir, &group, mode);
 874
 875got_group:
 876        EXT4_I(dir)->i_last_alloc_group = group;
 877        err = -ENOSPC;
 878        if (ret2 == -1)
 879                goto out;
 880
 881        /*
 882         * Normally we will only go through one pass of this loop,
 883         * unless we get unlucky and it turns out the group we selected
 884         * had its last inode grabbed by someone else.
 885         */
 886        for (i = 0; i < ngroups; i++, ino = 0) {
 887                err = -EIO;
 888
 889                gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
 890                if (!gdp)
 891                        goto out;
 892
 893                /*
 894                 * Check free inodes count before loading bitmap.
 895                 */
 896                if (ext4_free_inodes_count(sb, gdp) == 0)
 897                        goto next_group;
 898
 899                grp = ext4_get_group_info(sb, group);
 900                /* Skip groups with already-known suspicious inode tables */
 901                if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp))
 902                        goto next_group;
 903
 904                brelse(inode_bitmap_bh);
 905                inode_bitmap_bh = ext4_read_inode_bitmap(sb, group);
 906                /* Skip groups with suspicious inode tables */
 907                if (EXT4_MB_GRP_IBITMAP_CORRUPT(grp) ||
 908                    IS_ERR(inode_bitmap_bh)) {
 909                        inode_bitmap_bh = NULL;
 910                        goto next_group;
 911                }
 912
 913repeat_in_this_group:
 914                ret2 = find_inode_bit(sb, group, inode_bitmap_bh, &ino);
 915                if (!ret2)
 916                        goto next_group;
 917
 918                if (group == 0 && (ino + 1) < EXT4_FIRST_INO(sb)) {
 919                        ext4_error(sb, "reserved inode found cleared - "
 920                                   "inode=%lu", ino + 1);
 921                        ext4_mark_group_bitmap_corrupted(sb, group,
 922                                        EXT4_GROUP_INFO_IBITMAP_CORRUPT);
 923                        goto next_group;
 924                }
 925
 926                if (!handle) {
 927                        BUG_ON(nblocks <= 0);
 928                        handle = __ext4_journal_start_sb(dir->i_sb, line_no,
 929                                                         handle_type, nblocks,
 930                                                         0);
 931                        if (IS_ERR(handle)) {
 932                                err = PTR_ERR(handle);
 933                                ext4_std_error(sb, err);
 934                                goto out;
 935                        }
 936                }
 937                BUFFER_TRACE(inode_bitmap_bh, "get_write_access");
 938                err = ext4_journal_get_write_access(handle, inode_bitmap_bh);
 939                if (err) {
 940                        ext4_std_error(sb, err);
 941                        goto out;
 942                }
 943                ext4_lock_group(sb, group);
 944                ret2 = ext4_test_and_set_bit(ino, inode_bitmap_bh->b_data);
 945                if (ret2) {
 946                        /* Someone already took the bit. Repeat the search
 947                         * with lock held.
 948                         */
 949                        ret2 = find_inode_bit(sb, group, inode_bitmap_bh, &ino);
 950                        if (ret2) {
 951                                ext4_set_bit(ino, inode_bitmap_bh->b_data);
 952                                ret2 = 0;
 953                        } else {
 954                                ret2 = 1; /* we didn't grab the inode */
 955                        }
 956                }
 957                ext4_unlock_group(sb, group);
 958                ino++;          /* the inode bitmap is zero-based */
 959                if (!ret2)
 960                        goto got; /* we grabbed the inode! */
 961
 962                if (ino < EXT4_INODES_PER_GROUP(sb))
 963                        goto repeat_in_this_group;
 964next_group:
 965                if (++group == ngroups)
 966                        group = 0;
 967        }
 968        err = -ENOSPC;
 969        goto out;
 970
 971got:
 972        BUFFER_TRACE(inode_bitmap_bh, "call ext4_handle_dirty_metadata");
 973        err = ext4_handle_dirty_metadata(handle, NULL, inode_bitmap_bh);
 974        if (err) {
 975                ext4_std_error(sb, err);
 976                goto out;
 977        }
 978
 979        BUFFER_TRACE(group_desc_bh, "get_write_access");
 980        err = ext4_journal_get_write_access(handle, group_desc_bh);
 981        if (err) {
 982                ext4_std_error(sb, err);
 983                goto out;
 984        }
 985
 986        /* We may have to initialize the block bitmap if it isn't already */
 987        if (ext4_has_group_desc_csum(sb) &&
 988            gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 989                struct buffer_head *block_bitmap_bh;
 990
 991                block_bitmap_bh = ext4_read_block_bitmap(sb, group);
 992                if (IS_ERR(block_bitmap_bh)) {
 993                        err = PTR_ERR(block_bitmap_bh);
 994                        goto out;
 995                }
 996                BUFFER_TRACE(block_bitmap_bh, "get block bitmap access");
 997                err = ext4_journal_get_write_access(handle, block_bitmap_bh);
 998                if (err) {
 999                        brelse(block_bitmap_bh);
1000                        ext4_std_error(sb, err);
1001                        goto out;
1002                }
1003
1004                BUFFER_TRACE(block_bitmap_bh, "dirty block bitmap");
1005                err = ext4_handle_dirty_metadata(handle, NULL, block_bitmap_bh);
1006
1007                /* recheck and clear flag under lock if we still need to */
1008                ext4_lock_group(sb, group);
1009                if (ext4_has_group_desc_csum(sb) &&
1010                    (gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
1011                        gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
1012                        ext4_free_group_clusters_set(sb, gdp,
1013                                ext4_free_clusters_after_init(sb, group, gdp));
1014                        ext4_block_bitmap_csum_set(sb, group, gdp,
1015                                                   block_bitmap_bh);
1016                        ext4_group_desc_csum_set(sb, group, gdp);
1017                }
1018                ext4_unlock_group(sb, group);
1019                brelse(block_bitmap_bh);
1020
1021                if (err) {
1022                        ext4_std_error(sb, err);
1023                        goto out;
1024                }
1025        }
1026
1027        /* Update the relevant bg descriptor fields */
1028        if (ext4_has_group_desc_csum(sb)) {
1029                int free;
1030                struct ext4_group_info *grp = ext4_get_group_info(sb, group);
1031
1032                down_read(&grp->alloc_sem); /* protect vs itable lazyinit */
1033                ext4_lock_group(sb, group); /* while we modify the bg desc */
1034                free = EXT4_INODES_PER_GROUP(sb) -
1035                        ext4_itable_unused_count(sb, gdp);
1036                if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
1037                        gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT);
1038                        free = 0;
1039                }
1040                /*
1041                 * Check the relative inode number against the last used
1042                 * relative inode number in this group. if it is greater
1043                 * we need to update the bg_itable_unused count
1044                 */
1045                if (ino > free)
1046                        ext4_itable_unused_set(sb, gdp,
1047                                        (EXT4_INODES_PER_GROUP(sb) - ino));
1048                up_read(&grp->alloc_sem);
1049        } else {
1050                ext4_lock_group(sb, group);
1051        }
1052
1053        ext4_free_inodes_set(sb, gdp, ext4_free_inodes_count(sb, gdp) - 1);
1054        if (S_ISDIR(mode)) {
1055                ext4_used_dirs_set(sb, gdp, ext4_used_dirs_count(sb, gdp) + 1);
1056                if (sbi->s_log_groups_per_flex) {
1057                        ext4_group_t f = ext4_flex_group(sbi, group);
1058
1059                        atomic_inc(&sbi->s_flex_groups[f].used_dirs);
1060                }
1061        }
1062        if (ext4_has_group_desc_csum(sb)) {
1063                ext4_inode_bitmap_csum_set(sb, group, gdp, inode_bitmap_bh,
1064                                           EXT4_INODES_PER_GROUP(sb) / 8);
1065                ext4_group_desc_csum_set(sb, group, gdp);
1066        }
1067        ext4_unlock_group(sb, group);
1068
1069        BUFFER_TRACE(group_desc_bh, "call ext4_handle_dirty_metadata");
1070        err = ext4_handle_dirty_metadata(handle, NULL, group_desc_bh);
1071        if (err) {
1072                ext4_std_error(sb, err);
1073                goto out;
1074        }
1075
1076        percpu_counter_dec(&sbi->s_freeinodes_counter);
1077        if (S_ISDIR(mode))
1078                percpu_counter_inc(&sbi->s_dirs_counter);
1079
1080        if (sbi->s_log_groups_per_flex) {
1081                flex_group = ext4_flex_group(sbi, group);
1082                atomic_dec(&sbi->s_flex_groups[flex_group].free_inodes);
1083        }
1084
1085        inode->i_ino = ino + group * EXT4_INODES_PER_GROUP(sb);
1086        /* This is the optimal IO size (for stat), not the fs block size */
1087        inode->i_blocks = 0;
1088        inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
1089        ei->i_crtime = inode->i_mtime;
1090
1091        memset(ei->i_data, 0, sizeof(ei->i_data));
1092        ei->i_dir_start_lookup = 0;
1093        ei->i_disksize = 0;
1094
1095        /* Don't inherit extent flag from directory, amongst others. */
1096        ei->i_flags =
1097                ext4_mask_flags(mode, EXT4_I(dir)->i_flags & EXT4_FL_INHERITED);
1098        ei->i_flags |= i_flags;
1099        ei->i_file_acl = 0;
1100        ei->i_dtime = 0;
1101        ei->i_block_group = group;
1102        ei->i_last_alloc_group = ~0;
1103
1104        ext4_set_inode_flags(inode);
1105        if (IS_DIRSYNC(inode))
1106                ext4_handle_sync(handle);
1107        if (insert_inode_locked(inode) < 0) {
1108                /*
1109                 * Likely a bitmap corruption causing inode to be allocated
1110                 * twice.
1111                 */
1112                err = -EIO;
1113                ext4_error(sb, "failed to insert inode %lu: doubly allocated?",
1114                           inode->i_ino);
1115                ext4_mark_group_bitmap_corrupted(sb, group,
1116                                        EXT4_GROUP_INFO_IBITMAP_CORRUPT);
1117                goto out;
1118        }
1119        inode->i_generation = prandom_u32();
1120
1121        /* Precompute checksum seed for inode metadata */
1122        if (ext4_has_metadata_csum(sb)) {
1123                __u32 csum;
1124                __le32 inum = cpu_to_le32(inode->i_ino);
1125                __le32 gen = cpu_to_le32(inode->i_generation);
1126                csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&inum,
1127                                   sizeof(inum));
1128                ei->i_csum_seed = ext4_chksum(sbi, csum, (__u8 *)&gen,
1129                                              sizeof(gen));
1130        }
1131
1132        ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */
1133        ext4_set_inode_state(inode, EXT4_STATE_NEW);
1134
1135        ei->i_extra_isize = sbi->s_want_extra_isize;
1136        ei->i_inline_off = 0;
1137        if (ext4_has_feature_inline_data(sb))
1138                ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
1139        ret = inode;
1140        err = dquot_alloc_inode(inode);
1141        if (err)
1142                goto fail_drop;
1143
1144        /*
1145         * Since the encryption xattr will always be unique, create it first so
1146         * that it's less likely to end up in an external xattr block and
1147         * prevent its deduplication.
1148         */
1149        if (encrypt) {
1150                err = fscrypt_inherit_context(dir, inode, handle, true);
1151                if (err)
1152                        goto fail_free_drop;
1153        }
1154
1155        if (!(ei->i_flags & EXT4_EA_INODE_FL)) {
1156                err = ext4_init_acl(handle, inode, dir);
1157                if (err)
1158                        goto fail_free_drop;
1159
1160                err = ext4_init_security(handle, inode, dir, qstr);
1161                if (err)
1162                        goto fail_free_drop;
1163        }
1164
1165        if (ext4_has_feature_extents(sb)) {
1166                /* set extent flag only for directory, file and normal symlink*/
1167                if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) {
1168                        ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
1169                        ext4_ext_tree_init(handle, inode);
1170                }
1171        }
1172
1173        if (ext4_handle_valid(handle)) {
1174                ei->i_sync_tid = handle->h_transaction->t_tid;
1175                ei->i_datasync_tid = handle->h_transaction->t_tid;
1176        }
1177
1178        err = ext4_mark_inode_dirty(handle, inode);
1179        if (err) {
1180                ext4_std_error(sb, err);
1181                goto fail_free_drop;
1182        }
1183
1184        ext4_debug("allocating inode %lu\n", inode->i_ino);
1185        trace_ext4_allocate_inode(inode, dir, mode);
1186        brelse(inode_bitmap_bh);
1187        return ret;
1188
1189fail_free_drop:
1190        dquot_free_inode(inode);
1191fail_drop:
1192        clear_nlink(inode);
1193        unlock_new_inode(inode);
1194out:
1195        dquot_drop(inode);
1196        inode->i_flags |= S_NOQUOTA;
1197        iput(inode);
1198        brelse(inode_bitmap_bh);
1199        return ERR_PTR(err);
1200}
1201
1202/* Verify that we are loading a valid orphan from disk */
1203struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
1204{
1205        unsigned long max_ino = le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count);
1206        ext4_group_t block_group;
1207        int bit;
1208        struct buffer_head *bitmap_bh = NULL;
1209        struct inode *inode = NULL;
1210        int err = -EFSCORRUPTED;
1211
1212        if (ino < EXT4_FIRST_INO(sb) || ino > max_ino)
1213                goto bad_orphan;
1214
1215        block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
1216        bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
1217        bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
1218        if (IS_ERR(bitmap_bh))
1219                return ERR_CAST(bitmap_bh);
1220
1221        /* Having the inode bit set should be a 100% indicator that this
1222         * is a valid orphan (no e2fsck run on fs).  Orphans also include
1223         * inodes that were being truncated, so we can't check i_nlink==0.
1224         */
1225        if (!ext4_test_bit(bit, bitmap_bh->b_data))
1226                goto bad_orphan;
1227
1228        inode = ext4_iget(sb, ino, EXT4_IGET_NORMAL);
1229        if (IS_ERR(inode)) {
1230                err = PTR_ERR(inode);
1231                ext4_error(sb, "couldn't read orphan inode %lu (err %d)",
1232                           ino, err);
1233                return inode;
1234        }
1235
1236        /*
1237         * If the orphans has i_nlinks > 0 then it should be able to
1238         * be truncated, otherwise it won't be removed from the orphan
1239         * list during processing and an infinite loop will result.
1240         * Similarly, it must not be a bad inode.
1241         */
1242        if ((inode->i_nlink && !ext4_can_truncate(inode)) ||
1243            is_bad_inode(inode))
1244                goto bad_orphan;
1245
1246        if (NEXT_ORPHAN(inode) > max_ino)
1247                goto bad_orphan;
1248        brelse(bitmap_bh);
1249        return inode;
1250
1251bad_orphan:
1252        ext4_error(sb, "bad orphan inode %lu", ino);
1253        if (bitmap_bh)
1254                printk(KERN_ERR "ext4_test_bit(bit=%d, block=%llu) = %d\n",
1255                       bit, (unsigned long long)bitmap_bh->b_blocknr,
1256                       ext4_test_bit(bit, bitmap_bh->b_data));
1257        if (inode) {
1258                printk(KERN_ERR "is_bad_inode(inode)=%d\n",
1259                       is_bad_inode(inode));
1260                printk(KERN_ERR "NEXT_ORPHAN(inode)=%u\n",
1261                       NEXT_ORPHAN(inode));
1262                printk(KERN_ERR "max_ino=%lu\n", max_ino);
1263                printk(KERN_ERR "i_nlink=%u\n", inode->i_nlink);
1264                /* Avoid freeing blocks if we got a bad deleted inode */
1265                if (inode->i_nlink == 0)
1266                        inode->i_blocks = 0;
1267                iput(inode);
1268        }
1269        brelse(bitmap_bh);
1270        return ERR_PTR(err);
1271}
1272
1273unsigned long ext4_count_free_inodes(struct super_block *sb)
1274{
1275        unsigned long desc_count;
1276        struct ext4_group_desc *gdp;
1277        ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1278#ifdef EXT4FS_DEBUG
1279        struct ext4_super_block *es;
1280        unsigned long bitmap_count, x;
1281        struct buffer_head *bitmap_bh = NULL;
1282
1283        es = EXT4_SB(sb)->s_es;
1284        desc_count = 0;
1285        bitmap_count = 0;
1286        gdp = NULL;
1287        for (i = 0; i < ngroups; i++) {
1288                gdp = ext4_get_group_desc(sb, i, NULL);
1289                if (!gdp)
1290                        continue;
1291                desc_count += ext4_free_inodes_count(sb, gdp);
1292                brelse(bitmap_bh);
1293                bitmap_bh = ext4_read_inode_bitmap(sb, i);
1294                if (IS_ERR(bitmap_bh)) {
1295                        bitmap_bh = NULL;
1296                        continue;
1297                }
1298
1299                x = ext4_count_free(bitmap_bh->b_data,
1300                                    EXT4_INODES_PER_GROUP(sb) / 8);
1301                printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n",
1302                        (unsigned long) i, ext4_free_inodes_count(sb, gdp), x);
1303                bitmap_count += x;
1304        }
1305        brelse(bitmap_bh);
1306        printk(KERN_DEBUG "ext4_count_free_inodes: "
1307               "stored = %u, computed = %lu, %lu\n",
1308               le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
1309        return desc_count;
1310#else
1311        desc_count = 0;
1312        for (i = 0; i < ngroups; i++) {
1313                gdp = ext4_get_group_desc(sb, i, NULL);
1314                if (!gdp)
1315                        continue;
1316                desc_count += ext4_free_inodes_count(sb, gdp);
1317                cond_resched();
1318        }
1319        return desc_count;
1320#endif
1321}
1322
1323/* Called at mount-time, super-block is locked */
1324unsigned long ext4_count_dirs(struct super_block * sb)
1325{
1326        unsigned long count = 0;
1327        ext4_group_t i, ngroups = ext4_get_groups_count(sb);
1328
1329        for (i = 0; i < ngroups; i++) {
1330                struct ext4_group_desc *gdp = ext4_get_group_desc(sb, i, NULL);
1331                if (!gdp)
1332                        continue;
1333                count += ext4_used_dirs_count(sb, gdp);
1334        }
1335        return count;
1336}
1337
1338/*
1339 * Zeroes not yet zeroed inode table - just write zeroes through the whole
1340 * inode table. Must be called without any spinlock held. The only place
1341 * where it is called from on active part of filesystem is ext4lazyinit
1342 * thread, so we do not need any special locks, however we have to prevent
1343 * inode allocation from the current group, so we take alloc_sem lock, to
1344 * block ext4_new_inode() until we are finished.
1345 */
1346int ext4_init_inode_table(struct super_block *sb, ext4_group_t group,
1347                                 int barrier)
1348{
1349        struct ext4_group_info *grp = ext4_get_group_info(sb, group);
1350        struct ext4_sb_info *sbi = EXT4_SB(sb);
1351        struct ext4_group_desc *gdp = NULL;
1352        struct buffer_head *group_desc_bh;
1353        handle_t *handle;
1354        ext4_fsblk_t blk;
1355        int num, ret = 0, used_blks = 0;
1356
1357        /* This should not happen, but just to be sure check this */
1358        if (sb_rdonly(sb)) {
1359                ret = 1;
1360                goto out;
1361        }
1362
1363        gdp = ext4_get_group_desc(sb, group, &group_desc_bh);
1364        if (!gdp)
1365                goto out;
1366
1367        /*
1368         * We do not need to lock this, because we are the only one
1369         * handling this flag.
1370         */
1371        if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_ZEROED))
1372                goto out;
1373
1374        handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1);
1375        if (IS_ERR(handle)) {
1376                ret = PTR_ERR(handle);
1377                goto out;
1378        }
1379
1380        down_write(&grp->alloc_sem);
1381        /*
1382         * If inode bitmap was already initialized there may be some
1383         * used inodes so we need to skip blocks with used inodes in
1384         * inode table.
1385         */
1386        if (!(gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)))
1387                used_blks = DIV_ROUND_UP((EXT4_INODES_PER_GROUP(sb) -
1388                            ext4_itable_unused_count(sb, gdp)),
1389                            sbi->s_inodes_per_block);
1390
1391        if ((used_blks < 0) || (used_blks > sbi->s_itb_per_group) ||
1392            ((group == 0) && ((EXT4_INODES_PER_GROUP(sb) -
1393                               ext4_itable_unused_count(sb, gdp)) <
1394                              EXT4_FIRST_INO(sb)))) {
1395                ext4_error(sb, "Something is wrong with group %u: "
1396                           "used itable blocks: %d; "
1397                           "itable unused count: %u",
1398                           group, used_blks,
1399                           ext4_itable_unused_count(sb, gdp));
1400                ret = 1;
1401                goto err_out;
1402        }
1403
1404        blk = ext4_inode_table(sb, gdp) + used_blks;
1405        num = sbi->s_itb_per_group - used_blks;
1406
1407        BUFFER_TRACE(group_desc_bh, "get_write_access");
1408        ret = ext4_journal_get_write_access(handle,
1409                                            group_desc_bh);
1410        if (ret)
1411                goto err_out;
1412
1413        /*
1414         * Skip zeroout if the inode table is full. But we set the ZEROED
1415         * flag anyway, because obviously, when it is full it does not need
1416         * further zeroing.
1417         */
1418        if (unlikely(num == 0))
1419                goto skip_zeroout;
1420
1421        ext4_debug("going to zero out inode table in group %d\n",
1422                   group);
1423        ret = sb_issue_zeroout(sb, blk, num, GFP_NOFS);
1424        if (ret < 0)
1425                goto err_out;
1426        if (barrier)
1427                blkdev_issue_flush(sb->s_bdev, GFP_NOFS, NULL);
1428
1429skip_zeroout:
1430        ext4_lock_group(sb, group);
1431        gdp->bg_flags |= cpu_to_le16(EXT4_BG_INODE_ZEROED);
1432        ext4_group_desc_csum_set(sb, group, gdp);
1433        ext4_unlock_group(sb, group);
1434
1435        BUFFER_TRACE(group_desc_bh,
1436                     "call ext4_handle_dirty_metadata");
1437        ret = ext4_handle_dirty_metadata(handle, NULL,
1438                                         group_desc_bh);
1439
1440err_out:
1441        up_write(&grp->alloc_sem);
1442        ext4_journal_stop(handle);
1443out:
1444        return ret;
1445}
1446