linux/fs/ext4/dir.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 *  linux/fs/ext4/dir.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 *  from
  11 *
  12 *  linux/fs/minix/dir.c
  13 *
  14 *  Copyright (C) 1991, 1992  Linus Torvalds
  15 *
  16 *  ext4 directory handling functions
  17 *
  18 *  Big-endian to little-endian byte-swapping/bitmaps by
  19 *        David S. Miller (davem@caip.rutgers.edu), 1995
  20 *
  21 * Hash Tree Directory indexing (c) 2001  Daniel Phillips
  22 *
  23 */
  24
  25#include <linux/fs.h>
  26#include <linux/buffer_head.h>
  27#include <linux/slab.h>
  28#include <linux/iversion.h>
  29#include <linux/unicode.h>
  30#include "ext4.h"
  31#include "xattr.h"
  32
  33static int ext4_dx_readdir(struct file *, struct dir_context *);
  34
  35/**
  36 * is_dx_dir() - check if a directory is using htree indexing
  37 * @inode: directory inode
  38 *
  39 * Check if the given dir-inode refers to an htree-indexed directory
  40 * (or a directory which could potentially get converted to use htree
  41 * indexing).
  42 *
  43 * Return 1 if it is a dx dir, 0 if not
  44 */
  45static int is_dx_dir(struct inode *inode)
  46{
  47        struct super_block *sb = inode->i_sb;
  48
  49        if (ext4_has_feature_dir_index(inode->i_sb) &&
  50            ((ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) ||
  51             ((inode->i_size >> sb->s_blocksize_bits) == 1) ||
  52             ext4_has_inline_data(inode)))
  53                return 1;
  54
  55        return 0;
  56}
  57
  58/*
  59 * Return 0 if the directory entry is OK, and 1 if there is a problem
  60 *
  61 * Note: this is the opposite of what ext2 and ext3 historically returned...
  62 *
  63 * bh passed here can be an inode block or a dir data block, depending
  64 * on the inode inline data flag.
  65 */
  66int __ext4_check_dir_entry(const char *function, unsigned int line,
  67                           struct inode *dir, struct file *filp,
  68                           struct ext4_dir_entry_2 *de,
  69                           struct buffer_head *bh, char *buf, int size,
  70                           unsigned int offset)
  71{
  72        const char *error_msg = NULL;
  73        const int rlen = ext4_rec_len_from_disk(de->rec_len,
  74                                                dir->i_sb->s_blocksize);
  75
  76        if (unlikely(rlen < EXT4_DIR_REC_LEN(1)))
  77                error_msg = "rec_len is smaller than minimal";
  78        else if (unlikely(rlen % 4 != 0))
  79                error_msg = "rec_len % 4 != 0";
  80        else if (unlikely(rlen < EXT4_DIR_REC_LEN(de->name_len)))
  81                error_msg = "rec_len is too small for name_len";
  82        else if (unlikely(((char *) de - buf) + rlen > size))
  83                error_msg = "directory entry overrun";
  84        else if (unlikely(le32_to_cpu(de->inode) >
  85                        le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count)))
  86                error_msg = "inode out of bounds";
  87        else
  88                return 0;
  89
  90        if (filp)
  91                ext4_error_file(filp, function, line, bh->b_blocknr,
  92                                "bad entry in directory: %s - offset=%u, "
  93                                "inode=%u, rec_len=%d, name_len=%d, size=%d",
  94                                error_msg, offset, le32_to_cpu(de->inode),
  95                                rlen, de->name_len, size);
  96        else
  97                ext4_error_inode(dir, function, line, bh->b_blocknr,
  98                                "bad entry in directory: %s - offset=%u, "
  99                                "inode=%u, rec_len=%d, name_len=%d, size=%d",
 100                                 error_msg, offset, le32_to_cpu(de->inode),
 101                                 rlen, de->name_len, size);
 102
 103        return 1;
 104}
 105
 106static int ext4_readdir(struct file *file, struct dir_context *ctx)
 107{
 108        unsigned int offset;
 109        int i;
 110        struct ext4_dir_entry_2 *de;
 111        int err;
 112        struct inode *inode = file_inode(file);
 113        struct super_block *sb = inode->i_sb;
 114        struct buffer_head *bh = NULL;
 115        struct fscrypt_str fstr = FSTR_INIT(NULL, 0);
 116
 117        if (IS_ENCRYPTED(inode)) {
 118                err = fscrypt_get_encryption_info(inode);
 119                if (err && err != -ENOKEY)
 120                        return err;
 121        }
 122
 123        if (is_dx_dir(inode)) {
 124                err = ext4_dx_readdir(file, ctx);
 125                if (err != ERR_BAD_DX_DIR) {
 126                        return err;
 127                }
 128                /*
 129                 * We don't set the inode dirty flag since it's not
 130                 * critical that it get flushed back to the disk.
 131                 */
 132                ext4_clear_inode_flag(file_inode(file),
 133                                      EXT4_INODE_INDEX);
 134        }
 135
 136        if (ext4_has_inline_data(inode)) {
 137                int has_inline_data = 1;
 138                err = ext4_read_inline_dir(file, ctx,
 139                                           &has_inline_data);
 140                if (has_inline_data)
 141                        return err;
 142        }
 143
 144        if (IS_ENCRYPTED(inode)) {
 145                err = fscrypt_fname_alloc_buffer(inode, EXT4_NAME_LEN, &fstr);
 146                if (err < 0)
 147                        return err;
 148        }
 149
 150        while (ctx->pos < inode->i_size) {
 151                struct ext4_map_blocks map;
 152
 153                if (fatal_signal_pending(current)) {
 154                        err = -ERESTARTSYS;
 155                        goto errout;
 156                }
 157                cond_resched();
 158                offset = ctx->pos & (sb->s_blocksize - 1);
 159                map.m_lblk = ctx->pos >> EXT4_BLOCK_SIZE_BITS(sb);
 160                map.m_len = 1;
 161                err = ext4_map_blocks(NULL, inode, &map, 0);
 162                if (err == 0) {
 163                        /* m_len should never be zero but let's avoid
 164                         * an infinite loop if it somehow is */
 165                        if (map.m_len == 0)
 166                                map.m_len = 1;
 167                        ctx->pos += map.m_len * sb->s_blocksize;
 168                        continue;
 169                }
 170                if (err > 0) {
 171                        pgoff_t index = map.m_pblk >>
 172                                        (PAGE_SHIFT - inode->i_blkbits);
 173                        if (!ra_has_index(&file->f_ra, index))
 174                                page_cache_sync_readahead(
 175                                        sb->s_bdev->bd_inode->i_mapping,
 176                                        &file->f_ra, file,
 177                                        index, 1);
 178                        file->f_ra.prev_pos = (loff_t)index << PAGE_SHIFT;
 179                        bh = ext4_bread(NULL, inode, map.m_lblk, 0);
 180                        if (IS_ERR(bh)) {
 181                                err = PTR_ERR(bh);
 182                                bh = NULL;
 183                                goto errout;
 184                        }
 185                }
 186
 187                if (!bh) {
 188                        /* corrupt size?  Maybe no more blocks to read */
 189                        if (ctx->pos > inode->i_blocks << 9)
 190                                break;
 191                        ctx->pos += sb->s_blocksize - offset;
 192                        continue;
 193                }
 194
 195                /* Check the checksum */
 196                if (!buffer_verified(bh) &&
 197                    !ext4_dirblock_csum_verify(inode, bh)) {
 198                        EXT4_ERROR_FILE(file, 0, "directory fails checksum "
 199                                        "at offset %llu",
 200                                        (unsigned long long)ctx->pos);
 201                        ctx->pos += sb->s_blocksize - offset;
 202                        brelse(bh);
 203                        bh = NULL;
 204                        continue;
 205                }
 206                set_buffer_verified(bh);
 207
 208                /* If the dir block has changed since the last call to
 209                 * readdir(2), then we might be pointing to an invalid
 210                 * dirent right now.  Scan from the start of the block
 211                 * to make sure. */
 212                if (!inode_eq_iversion(inode, file->f_version)) {
 213                        for (i = 0; i < sb->s_blocksize && i < offset; ) {
 214                                de = (struct ext4_dir_entry_2 *)
 215                                        (bh->b_data + i);
 216                                /* It's too expensive to do a full
 217                                 * dirent test each time round this
 218                                 * loop, but we do have to test at
 219                                 * least that it is non-zero.  A
 220                                 * failure will be detected in the
 221                                 * dirent test below. */
 222                                if (ext4_rec_len_from_disk(de->rec_len,
 223                                        sb->s_blocksize) < EXT4_DIR_REC_LEN(1))
 224                                        break;
 225                                i += ext4_rec_len_from_disk(de->rec_len,
 226                                                            sb->s_blocksize);
 227                        }
 228                        offset = i;
 229                        ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1))
 230                                | offset;
 231                        file->f_version = inode_query_iversion(inode);
 232                }
 233
 234                while (ctx->pos < inode->i_size
 235                       && offset < sb->s_blocksize) {
 236                        de = (struct ext4_dir_entry_2 *) (bh->b_data + offset);
 237                        if (ext4_check_dir_entry(inode, file, de, bh,
 238                                                 bh->b_data, bh->b_size,
 239                                                 offset)) {
 240                                /*
 241                                 * On error, skip to the next block
 242                                 */
 243                                ctx->pos = (ctx->pos |
 244                                                (sb->s_blocksize - 1)) + 1;
 245                                break;
 246                        }
 247                        offset += ext4_rec_len_from_disk(de->rec_len,
 248                                        sb->s_blocksize);
 249                        if (le32_to_cpu(de->inode)) {
 250                                if (!IS_ENCRYPTED(inode)) {
 251                                        if (!dir_emit(ctx, de->name,
 252                                            de->name_len,
 253                                            le32_to_cpu(de->inode),
 254                                            get_dtype(sb, de->file_type)))
 255                                                goto done;
 256                                } else {
 257                                        int save_len = fstr.len;
 258                                        struct fscrypt_str de_name =
 259                                                        FSTR_INIT(de->name,
 260                                                                de->name_len);
 261
 262                                        /* Directory is encrypted */
 263                                        err = fscrypt_fname_disk_to_usr(inode,
 264                                                0, 0, &de_name, &fstr);
 265                                        de_name = fstr;
 266                                        fstr.len = save_len;
 267                                        if (err)
 268                                                goto errout;
 269                                        if (!dir_emit(ctx,
 270                                            de_name.name, de_name.len,
 271                                            le32_to_cpu(de->inode),
 272                                            get_dtype(sb, de->file_type)))
 273                                                goto done;
 274                                }
 275                        }
 276                        ctx->pos += ext4_rec_len_from_disk(de->rec_len,
 277                                                sb->s_blocksize);
 278                }
 279                if ((ctx->pos < inode->i_size) && !dir_relax_shared(inode))
 280                        goto done;
 281                brelse(bh);
 282                bh = NULL;
 283                offset = 0;
 284        }
 285done:
 286        err = 0;
 287errout:
 288        fscrypt_fname_free_buffer(&fstr);
 289        brelse(bh);
 290        return err;
 291}
 292
 293static inline int is_32bit_api(void)
 294{
 295#ifdef CONFIG_COMPAT
 296        return in_compat_syscall();
 297#else
 298        return (BITS_PER_LONG == 32);
 299#endif
 300}
 301
 302/*
 303 * These functions convert from the major/minor hash to an f_pos
 304 * value for dx directories
 305 *
 306 * Upper layer (for example NFS) should specify FMODE_32BITHASH or
 307 * FMODE_64BITHASH explicitly. On the other hand, we allow ext4 to be mounted
 308 * directly on both 32-bit and 64-bit nodes, under such case, neither
 309 * FMODE_32BITHASH nor FMODE_64BITHASH is specified.
 310 */
 311static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor)
 312{
 313        if ((filp->f_mode & FMODE_32BITHASH) ||
 314            (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
 315                return major >> 1;
 316        else
 317                return ((__u64)(major >> 1) << 32) | (__u64)minor;
 318}
 319
 320static inline __u32 pos2maj_hash(struct file *filp, loff_t pos)
 321{
 322        if ((filp->f_mode & FMODE_32BITHASH) ||
 323            (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
 324                return (pos << 1) & 0xffffffff;
 325        else
 326                return ((pos >> 32) << 1) & 0xffffffff;
 327}
 328
 329static inline __u32 pos2min_hash(struct file *filp, loff_t pos)
 330{
 331        if ((filp->f_mode & FMODE_32BITHASH) ||
 332            (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
 333                return 0;
 334        else
 335                return pos & 0xffffffff;
 336}
 337
 338/*
 339 * Return 32- or 64-bit end-of-file for dx directories
 340 */
 341static inline loff_t ext4_get_htree_eof(struct file *filp)
 342{
 343        if ((filp->f_mode & FMODE_32BITHASH) ||
 344            (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
 345                return EXT4_HTREE_EOF_32BIT;
 346        else
 347                return EXT4_HTREE_EOF_64BIT;
 348}
 349
 350
 351/*
 352 * ext4_dir_llseek() calls generic_file_llseek_size to handle htree
 353 * directories, where the "offset" is in terms of the filename hash
 354 * value instead of the byte offset.
 355 *
 356 * Because we may return a 64-bit hash that is well beyond offset limits,
 357 * we need to pass the max hash as the maximum allowable offset in
 358 * the htree directory case.
 359 *
 360 * For non-htree, ext4_llseek already chooses the proper max offset.
 361 */
 362static loff_t ext4_dir_llseek(struct file *file, loff_t offset, int whence)
 363{
 364        struct inode *inode = file->f_mapping->host;
 365        int dx_dir = is_dx_dir(inode);
 366        loff_t ret, htree_max = ext4_get_htree_eof(file);
 367
 368        if (likely(dx_dir))
 369                ret = generic_file_llseek_size(file, offset, whence,
 370                                                    htree_max, htree_max);
 371        else
 372                ret = ext4_llseek(file, offset, whence);
 373        file->f_version = inode_peek_iversion(inode) - 1;
 374        return ret;
 375}
 376
 377/*
 378 * This structure holds the nodes of the red-black tree used to store
 379 * the directory entry in hash order.
 380 */
 381struct fname {
 382        __u32           hash;
 383        __u32           minor_hash;
 384        struct rb_node  rb_hash;
 385        struct fname    *next;
 386        __u32           inode;
 387        __u8            name_len;
 388        __u8            file_type;
 389        char            name[0];
 390};
 391
 392/*
 393 * This functoin implements a non-recursive way of freeing all of the
 394 * nodes in the red-black tree.
 395 */
 396static void free_rb_tree_fname(struct rb_root *root)
 397{
 398        struct fname *fname, *next;
 399
 400        rbtree_postorder_for_each_entry_safe(fname, next, root, rb_hash)
 401                while (fname) {
 402                        struct fname *old = fname;
 403                        fname = fname->next;
 404                        kfree(old);
 405                }
 406
 407        *root = RB_ROOT;
 408}
 409
 410
 411static struct dir_private_info *ext4_htree_create_dir_info(struct file *filp,
 412                                                           loff_t pos)
 413{
 414        struct dir_private_info *p;
 415
 416        p = kzalloc(sizeof(*p), GFP_KERNEL);
 417        if (!p)
 418                return NULL;
 419        p->curr_hash = pos2maj_hash(filp, pos);
 420        p->curr_minor_hash = pos2min_hash(filp, pos);
 421        return p;
 422}
 423
 424void ext4_htree_free_dir_info(struct dir_private_info *p)
 425{
 426        free_rb_tree_fname(&p->root);
 427        kfree(p);
 428}
 429
 430/*
 431 * Given a directory entry, enter it into the fname rb tree.
 432 *
 433 * When filename encryption is enabled, the dirent will hold the
 434 * encrypted filename, while the htree will hold decrypted filename.
 435 * The decrypted filename is passed in via ent_name.  parameter.
 436 */
 437int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
 438                             __u32 minor_hash,
 439                            struct ext4_dir_entry_2 *dirent,
 440                            struct fscrypt_str *ent_name)
 441{
 442        struct rb_node **p, *parent = NULL;
 443        struct fname *fname, *new_fn;
 444        struct dir_private_info *info;
 445        int len;
 446
 447        info = dir_file->private_data;
 448        p = &info->root.rb_node;
 449
 450        /* Create and allocate the fname structure */
 451        len = sizeof(struct fname) + ent_name->len + 1;
 452        new_fn = kzalloc(len, GFP_KERNEL);
 453        if (!new_fn)
 454                return -ENOMEM;
 455        new_fn->hash = hash;
 456        new_fn->minor_hash = minor_hash;
 457        new_fn->inode = le32_to_cpu(dirent->inode);
 458        new_fn->name_len = ent_name->len;
 459        new_fn->file_type = dirent->file_type;
 460        memcpy(new_fn->name, ent_name->name, ent_name->len);
 461        new_fn->name[ent_name->len] = 0;
 462
 463        while (*p) {
 464                parent = *p;
 465                fname = rb_entry(parent, struct fname, rb_hash);
 466
 467                /*
 468                 * If the hash and minor hash match up, then we put
 469                 * them on a linked list.  This rarely happens...
 470                 */
 471                if ((new_fn->hash == fname->hash) &&
 472                    (new_fn->minor_hash == fname->minor_hash)) {
 473                        new_fn->next = fname->next;
 474                        fname->next = new_fn;
 475                        return 0;
 476                }
 477
 478                if (new_fn->hash < fname->hash)
 479                        p = &(*p)->rb_left;
 480                else if (new_fn->hash > fname->hash)
 481                        p = &(*p)->rb_right;
 482                else if (new_fn->minor_hash < fname->minor_hash)
 483                        p = &(*p)->rb_left;
 484                else /* if (new_fn->minor_hash > fname->minor_hash) */
 485                        p = &(*p)->rb_right;
 486        }
 487
 488        rb_link_node(&new_fn->rb_hash, parent, p);
 489        rb_insert_color(&new_fn->rb_hash, &info->root);
 490        return 0;
 491}
 492
 493
 494
 495/*
 496 * This is a helper function for ext4_dx_readdir.  It calls filldir
 497 * for all entres on the fname linked list.  (Normally there is only
 498 * one entry on the linked list, unless there are 62 bit hash collisions.)
 499 */
 500static int call_filldir(struct file *file, struct dir_context *ctx,
 501                        struct fname *fname)
 502{
 503        struct dir_private_info *info = file->private_data;
 504        struct inode *inode = file_inode(file);
 505        struct super_block *sb = inode->i_sb;
 506
 507        if (!fname) {
 508                ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: comm %s: "
 509                         "called with null fname?!?", __func__, __LINE__,
 510                         inode->i_ino, current->comm);
 511                return 0;
 512        }
 513        ctx->pos = hash2pos(file, fname->hash, fname->minor_hash);
 514        while (fname) {
 515                if (!dir_emit(ctx, fname->name,
 516                                fname->name_len,
 517                                fname->inode,
 518                                get_dtype(sb, fname->file_type))) {
 519                        info->extra_fname = fname;
 520                        return 1;
 521                }
 522                fname = fname->next;
 523        }
 524        return 0;
 525}
 526
 527static int ext4_dx_readdir(struct file *file, struct dir_context *ctx)
 528{
 529        struct dir_private_info *info = file->private_data;
 530        struct inode *inode = file_inode(file);
 531        struct fname *fname;
 532        int     ret;
 533
 534        if (!info) {
 535                info = ext4_htree_create_dir_info(file, ctx->pos);
 536                if (!info)
 537                        return -ENOMEM;
 538                file->private_data = info;
 539        }
 540
 541        if (ctx->pos == ext4_get_htree_eof(file))
 542                return 0;       /* EOF */
 543
 544        /* Some one has messed with f_pos; reset the world */
 545        if (info->last_pos != ctx->pos) {
 546                free_rb_tree_fname(&info->root);
 547                info->curr_node = NULL;
 548                info->extra_fname = NULL;
 549                info->curr_hash = pos2maj_hash(file, ctx->pos);
 550                info->curr_minor_hash = pos2min_hash(file, ctx->pos);
 551        }
 552
 553        /*
 554         * If there are any leftover names on the hash collision
 555         * chain, return them first.
 556         */
 557        if (info->extra_fname) {
 558                if (call_filldir(file, ctx, info->extra_fname))
 559                        goto finished;
 560                info->extra_fname = NULL;
 561                goto next_node;
 562        } else if (!info->curr_node)
 563                info->curr_node = rb_first(&info->root);
 564
 565        while (1) {
 566                /*
 567                 * Fill the rbtree if we have no more entries,
 568                 * or the inode has changed since we last read in the
 569                 * cached entries.
 570                 */
 571                if ((!info->curr_node) ||
 572                    !inode_eq_iversion(inode, file->f_version)) {
 573                        info->curr_node = NULL;
 574                        free_rb_tree_fname(&info->root);
 575                        file->f_version = inode_query_iversion(inode);
 576                        ret = ext4_htree_fill_tree(file, info->curr_hash,
 577                                                   info->curr_minor_hash,
 578                                                   &info->next_hash);
 579                        if (ret < 0)
 580                                return ret;
 581                        if (ret == 0) {
 582                                ctx->pos = ext4_get_htree_eof(file);
 583                                break;
 584                        }
 585                        info->curr_node = rb_first(&info->root);
 586                }
 587
 588                fname = rb_entry(info->curr_node, struct fname, rb_hash);
 589                info->curr_hash = fname->hash;
 590                info->curr_minor_hash = fname->minor_hash;
 591                if (call_filldir(file, ctx, fname))
 592                        break;
 593        next_node:
 594                info->curr_node = rb_next(info->curr_node);
 595                if (info->curr_node) {
 596                        fname = rb_entry(info->curr_node, struct fname,
 597                                         rb_hash);
 598                        info->curr_hash = fname->hash;
 599                        info->curr_minor_hash = fname->minor_hash;
 600                } else {
 601                        if (info->next_hash == ~0) {
 602                                ctx->pos = ext4_get_htree_eof(file);
 603                                break;
 604                        }
 605                        info->curr_hash = info->next_hash;
 606                        info->curr_minor_hash = 0;
 607                }
 608        }
 609finished:
 610        info->last_pos = ctx->pos;
 611        return 0;
 612}
 613
 614static int ext4_dir_open(struct inode * inode, struct file * filp)
 615{
 616        if (IS_ENCRYPTED(inode))
 617                return fscrypt_get_encryption_info(inode) ? -EACCES : 0;
 618        return 0;
 619}
 620
 621static int ext4_release_dir(struct inode *inode, struct file *filp)
 622{
 623        if (filp->private_data)
 624                ext4_htree_free_dir_info(filp->private_data);
 625
 626        return 0;
 627}
 628
 629int ext4_check_all_de(struct inode *dir, struct buffer_head *bh, void *buf,
 630                      int buf_size)
 631{
 632        struct ext4_dir_entry_2 *de;
 633        int rlen;
 634        unsigned int offset = 0;
 635        char *top;
 636
 637        de = (struct ext4_dir_entry_2 *)buf;
 638        top = buf + buf_size;
 639        while ((char *) de < top) {
 640                if (ext4_check_dir_entry(dir, NULL, de, bh,
 641                                         buf, buf_size, offset))
 642                        return -EFSCORRUPTED;
 643                rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
 644                de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
 645                offset += rlen;
 646        }
 647        if ((char *) de > top)
 648                return -EFSCORRUPTED;
 649
 650        return 0;
 651}
 652
 653const struct file_operations ext4_dir_operations = {
 654        .llseek         = ext4_dir_llseek,
 655        .read           = generic_read_dir,
 656        .iterate_shared = ext4_readdir,
 657        .unlocked_ioctl = ext4_ioctl,
 658#ifdef CONFIG_COMPAT
 659        .compat_ioctl   = ext4_compat_ioctl,
 660#endif
 661        .fsync          = ext4_sync_file,
 662        .open           = ext4_dir_open,
 663        .release        = ext4_release_dir,
 664};
 665
 666#ifdef CONFIG_UNICODE
 667static int ext4_d_compare(const struct dentry *dentry, unsigned int len,
 668                          const char *str, const struct qstr *name)
 669{
 670        struct qstr qstr = {.name = str, .len = len };
 671        struct inode *inode = dentry->d_parent->d_inode;
 672
 673        if (!IS_CASEFOLDED(inode) || !EXT4_SB(inode->i_sb)->s_encoding) {
 674                if (len != name->len)
 675                        return -1;
 676                return memcmp(str, name->name, len);
 677        }
 678
 679        return ext4_ci_compare(inode, name, &qstr, false);
 680}
 681
 682static int ext4_d_hash(const struct dentry *dentry, struct qstr *str)
 683{
 684        const struct ext4_sb_info *sbi = EXT4_SB(dentry->d_sb);
 685        const struct unicode_map *um = sbi->s_encoding;
 686        unsigned char *norm;
 687        int len, ret = 0;
 688
 689        if (!IS_CASEFOLDED(dentry->d_inode) || !um)
 690                return 0;
 691
 692        norm = kmalloc(PATH_MAX, GFP_ATOMIC);
 693        if (!norm)
 694                return -ENOMEM;
 695
 696        len = utf8_casefold(um, str, norm, PATH_MAX);
 697        if (len < 0) {
 698                if (ext4_has_strict_mode(sbi))
 699                        ret = -EINVAL;
 700                goto out;
 701        }
 702        str->hash = full_name_hash(dentry, norm, len);
 703out:
 704        kfree(norm);
 705        return ret;
 706}
 707
 708const struct dentry_operations ext4_dentry_ops = {
 709        .d_hash = ext4_d_hash,
 710        .d_compare = ext4_d_compare,
 711};
 712#endif
 713