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        const int next_offset = ((char *) de - buf) + rlen;
  76
  77        if (unlikely(rlen < EXT4_DIR_REC_LEN(1)))
  78                error_msg = "rec_len is smaller than minimal";
  79        else if (unlikely(rlen % 4 != 0))
  80                error_msg = "rec_len % 4 != 0";
  81        else if (unlikely(rlen < EXT4_DIR_REC_LEN(de->name_len)))
  82                error_msg = "rec_len is too small for name_len";
  83        else if (unlikely(next_offset > size))
  84                error_msg = "directory entry overrun";
  85        else if (unlikely(next_offset > size - EXT4_DIR_REC_LEN(1) &&
  86                          next_offset != size))
  87                error_msg = "directory entry too close to block end";
  88        else if (unlikely(le32_to_cpu(de->inode) >
  89                        le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count)))
  90                error_msg = "inode out of bounds";
  91        else
  92                return 0;
  93
  94        if (filp)
  95                ext4_error_file(filp, function, line, bh->b_blocknr,
  96                                "bad entry in directory: %s - offset=%u, "
  97                                "inode=%u, rec_len=%d, name_len=%d, size=%d",
  98                                error_msg, offset, le32_to_cpu(de->inode),
  99                                rlen, de->name_len, size);
 100        else
 101                ext4_error_inode(dir, function, line, bh->b_blocknr,
 102                                "bad entry in directory: %s - offset=%u, "
 103                                "inode=%u, rec_len=%d, name_len=%d, size=%d",
 104                                 error_msg, offset, le32_to_cpu(de->inode),
 105                                 rlen, de->name_len, size);
 106
 107        return 1;
 108}
 109
 110static int ext4_readdir(struct file *file, struct dir_context *ctx)
 111{
 112        unsigned int offset;
 113        int i;
 114        struct ext4_dir_entry_2 *de;
 115        int err;
 116        struct inode *inode = file_inode(file);
 117        struct super_block *sb = inode->i_sb;
 118        struct buffer_head *bh = NULL;
 119        struct fscrypt_str fstr = FSTR_INIT(NULL, 0);
 120
 121        if (IS_ENCRYPTED(inode)) {
 122                err = fscrypt_get_encryption_info(inode);
 123                if (err)
 124                        return err;
 125        }
 126
 127        if (is_dx_dir(inode)) {
 128                err = ext4_dx_readdir(file, ctx);
 129                if (err != ERR_BAD_DX_DIR) {
 130                        return err;
 131                }
 132                /* Can we just clear INDEX flag to ignore htree information? */
 133                if (!ext4_has_metadata_csum(sb)) {
 134                        /*
 135                         * We don't set the inode dirty flag since it's not
 136                         * critical that it gets flushed back to the disk.
 137                         */
 138                        ext4_clear_inode_flag(inode, EXT4_INODE_INDEX);
 139                }
 140        }
 141
 142        if (ext4_has_inline_data(inode)) {
 143                int has_inline_data = 1;
 144                err = ext4_read_inline_dir(file, ctx,
 145                                           &has_inline_data);
 146                if (has_inline_data)
 147                        return err;
 148        }
 149
 150        if (IS_ENCRYPTED(inode)) {
 151                err = fscrypt_fname_alloc_buffer(inode, EXT4_NAME_LEN, &fstr);
 152                if (err < 0)
 153                        return err;
 154        }
 155
 156        while (ctx->pos < inode->i_size) {
 157                struct ext4_map_blocks map;
 158
 159                if (fatal_signal_pending(current)) {
 160                        err = -ERESTARTSYS;
 161                        goto errout;
 162                }
 163                cond_resched();
 164                offset = ctx->pos & (sb->s_blocksize - 1);
 165                map.m_lblk = ctx->pos >> EXT4_BLOCK_SIZE_BITS(sb);
 166                map.m_len = 1;
 167                err = ext4_map_blocks(NULL, inode, &map, 0);
 168                if (err == 0) {
 169                        /* m_len should never be zero but let's avoid
 170                         * an infinite loop if it somehow is */
 171                        if (map.m_len == 0)
 172                                map.m_len = 1;
 173                        ctx->pos += map.m_len * sb->s_blocksize;
 174                        continue;
 175                }
 176                if (err > 0) {
 177                        pgoff_t index = map.m_pblk >>
 178                                        (PAGE_SHIFT - inode->i_blkbits);
 179                        if (!ra_has_index(&file->f_ra, index))
 180                                page_cache_sync_readahead(
 181                                        sb->s_bdev->bd_inode->i_mapping,
 182                                        &file->f_ra, file,
 183                                        index, 1);
 184                        file->f_ra.prev_pos = (loff_t)index << PAGE_SHIFT;
 185                        bh = ext4_bread(NULL, inode, map.m_lblk, 0);
 186                        if (IS_ERR(bh)) {
 187                                err = PTR_ERR(bh);
 188                                bh = NULL;
 189                                goto errout;
 190                        }
 191                }
 192
 193                if (!bh) {
 194                        /* corrupt size?  Maybe no more blocks to read */
 195                        if (ctx->pos > inode->i_blocks << 9)
 196                                break;
 197                        ctx->pos += sb->s_blocksize - offset;
 198                        continue;
 199                }
 200
 201                /* Check the checksum */
 202                if (!buffer_verified(bh) &&
 203                    !ext4_dirblock_csum_verify(inode, bh)) {
 204                        EXT4_ERROR_FILE(file, 0, "directory fails checksum "
 205                                        "at offset %llu",
 206                                        (unsigned long long)ctx->pos);
 207                        ctx->pos += sb->s_blocksize - offset;
 208                        brelse(bh);
 209                        bh = NULL;
 210                        continue;
 211                }
 212                set_buffer_verified(bh);
 213
 214                /* If the dir block has changed since the last call to
 215                 * readdir(2), then we might be pointing to an invalid
 216                 * dirent right now.  Scan from the start of the block
 217                 * to make sure. */
 218                if (!inode_eq_iversion(inode, file->f_version)) {
 219                        for (i = 0; i < sb->s_blocksize && i < offset; ) {
 220                                de = (struct ext4_dir_entry_2 *)
 221                                        (bh->b_data + i);
 222                                /* It's too expensive to do a full
 223                                 * dirent test each time round this
 224                                 * loop, but we do have to test at
 225                                 * least that it is non-zero.  A
 226                                 * failure will be detected in the
 227                                 * dirent test below. */
 228                                if (ext4_rec_len_from_disk(de->rec_len,
 229                                        sb->s_blocksize) < EXT4_DIR_REC_LEN(1))
 230                                        break;
 231                                i += ext4_rec_len_from_disk(de->rec_len,
 232                                                            sb->s_blocksize);
 233                        }
 234                        offset = i;
 235                        ctx->pos = (ctx->pos & ~(sb->s_blocksize - 1))
 236                                | offset;
 237                        file->f_version = inode_query_iversion(inode);
 238                }
 239
 240                while (ctx->pos < inode->i_size
 241                       && offset < sb->s_blocksize) {
 242                        de = (struct ext4_dir_entry_2 *) (bh->b_data + offset);
 243                        if (ext4_check_dir_entry(inode, file, de, bh,
 244                                                 bh->b_data, bh->b_size,
 245                                                 offset)) {
 246                                /*
 247                                 * On error, skip to the next block
 248                                 */
 249                                ctx->pos = (ctx->pos |
 250                                                (sb->s_blocksize - 1)) + 1;
 251                                break;
 252                        }
 253                        offset += ext4_rec_len_from_disk(de->rec_len,
 254                                        sb->s_blocksize);
 255                        if (le32_to_cpu(de->inode)) {
 256                                if (!IS_ENCRYPTED(inode)) {
 257                                        if (!dir_emit(ctx, de->name,
 258                                            de->name_len,
 259                                            le32_to_cpu(de->inode),
 260                                            get_dtype(sb, de->file_type)))
 261                                                goto done;
 262                                } else {
 263                                        int save_len = fstr.len;
 264                                        struct fscrypt_str de_name =
 265                                                        FSTR_INIT(de->name,
 266                                                                de->name_len);
 267
 268                                        /* Directory is encrypted */
 269                                        err = fscrypt_fname_disk_to_usr(inode,
 270                                                0, 0, &de_name, &fstr);
 271                                        de_name = fstr;
 272                                        fstr.len = save_len;
 273                                        if (err)
 274                                                goto errout;
 275                                        if (!dir_emit(ctx,
 276                                            de_name.name, de_name.len,
 277                                            le32_to_cpu(de->inode),
 278                                            get_dtype(sb, de->file_type)))
 279                                                goto done;
 280                                }
 281                        }
 282                        ctx->pos += ext4_rec_len_from_disk(de->rec_len,
 283                                                sb->s_blocksize);
 284                }
 285                if ((ctx->pos < inode->i_size) && !dir_relax_shared(inode))
 286                        goto done;
 287                brelse(bh);
 288                bh = NULL;
 289                offset = 0;
 290        }
 291done:
 292        err = 0;
 293errout:
 294        fscrypt_fname_free_buffer(&fstr);
 295        brelse(bh);
 296        return err;
 297}
 298
 299static inline int is_32bit_api(void)
 300{
 301#ifdef CONFIG_COMPAT
 302        return in_compat_syscall();
 303#else
 304        return (BITS_PER_LONG == 32);
 305#endif
 306}
 307
 308/*
 309 * These functions convert from the major/minor hash to an f_pos
 310 * value for dx directories
 311 *
 312 * Upper layer (for example NFS) should specify FMODE_32BITHASH or
 313 * FMODE_64BITHASH explicitly. On the other hand, we allow ext4 to be mounted
 314 * directly on both 32-bit and 64-bit nodes, under such case, neither
 315 * FMODE_32BITHASH nor FMODE_64BITHASH is specified.
 316 */
 317static inline loff_t hash2pos(struct file *filp, __u32 major, __u32 minor)
 318{
 319        if ((filp->f_mode & FMODE_32BITHASH) ||
 320            (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
 321                return major >> 1;
 322        else
 323                return ((__u64)(major >> 1) << 32) | (__u64)minor;
 324}
 325
 326static inline __u32 pos2maj_hash(struct file *filp, loff_t pos)
 327{
 328        if ((filp->f_mode & FMODE_32BITHASH) ||
 329            (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
 330                return (pos << 1) & 0xffffffff;
 331        else
 332                return ((pos >> 32) << 1) & 0xffffffff;
 333}
 334
 335static inline __u32 pos2min_hash(struct file *filp, loff_t pos)
 336{
 337        if ((filp->f_mode & FMODE_32BITHASH) ||
 338            (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
 339                return 0;
 340        else
 341                return pos & 0xffffffff;
 342}
 343
 344/*
 345 * Return 32- or 64-bit end-of-file for dx directories
 346 */
 347static inline loff_t ext4_get_htree_eof(struct file *filp)
 348{
 349        if ((filp->f_mode & FMODE_32BITHASH) ||
 350            (!(filp->f_mode & FMODE_64BITHASH) && is_32bit_api()))
 351                return EXT4_HTREE_EOF_32BIT;
 352        else
 353                return EXT4_HTREE_EOF_64BIT;
 354}
 355
 356
 357/*
 358 * ext4_dir_llseek() calls generic_file_llseek_size to handle htree
 359 * directories, where the "offset" is in terms of the filename hash
 360 * value instead of the byte offset.
 361 *
 362 * Because we may return a 64-bit hash that is well beyond offset limits,
 363 * we need to pass the max hash as the maximum allowable offset in
 364 * the htree directory case.
 365 *
 366 * For non-htree, ext4_llseek already chooses the proper max offset.
 367 */
 368static loff_t ext4_dir_llseek(struct file *file, loff_t offset, int whence)
 369{
 370        struct inode *inode = file->f_mapping->host;
 371        int dx_dir = is_dx_dir(inode);
 372        loff_t ret, htree_max = ext4_get_htree_eof(file);
 373
 374        if (likely(dx_dir))
 375                ret = generic_file_llseek_size(file, offset, whence,
 376                                                    htree_max, htree_max);
 377        else
 378                ret = ext4_llseek(file, offset, whence);
 379        file->f_version = inode_peek_iversion(inode) - 1;
 380        return ret;
 381}
 382
 383/*
 384 * This structure holds the nodes of the red-black tree used to store
 385 * the directory entry in hash order.
 386 */
 387struct fname {
 388        __u32           hash;
 389        __u32           minor_hash;
 390        struct rb_node  rb_hash;
 391        struct fname    *next;
 392        __u32           inode;
 393        __u8            name_len;
 394        __u8            file_type;
 395        char            name[0];
 396};
 397
 398/*
 399 * This functoin implements a non-recursive way of freeing all of the
 400 * nodes in the red-black tree.
 401 */
 402static void free_rb_tree_fname(struct rb_root *root)
 403{
 404        struct fname *fname, *next;
 405
 406        rbtree_postorder_for_each_entry_safe(fname, next, root, rb_hash)
 407                while (fname) {
 408                        struct fname *old = fname;
 409                        fname = fname->next;
 410                        kfree(old);
 411                }
 412
 413        *root = RB_ROOT;
 414}
 415
 416
 417static struct dir_private_info *ext4_htree_create_dir_info(struct file *filp,
 418                                                           loff_t pos)
 419{
 420        struct dir_private_info *p;
 421
 422        p = kzalloc(sizeof(*p), GFP_KERNEL);
 423        if (!p)
 424                return NULL;
 425        p->curr_hash = pos2maj_hash(filp, pos);
 426        p->curr_minor_hash = pos2min_hash(filp, pos);
 427        return p;
 428}
 429
 430void ext4_htree_free_dir_info(struct dir_private_info *p)
 431{
 432        free_rb_tree_fname(&p->root);
 433        kfree(p);
 434}
 435
 436/*
 437 * Given a directory entry, enter it into the fname rb tree.
 438 *
 439 * When filename encryption is enabled, the dirent will hold the
 440 * encrypted filename, while the htree will hold decrypted filename.
 441 * The decrypted filename is passed in via ent_name.  parameter.
 442 */
 443int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
 444                             __u32 minor_hash,
 445                            struct ext4_dir_entry_2 *dirent,
 446                            struct fscrypt_str *ent_name)
 447{
 448        struct rb_node **p, *parent = NULL;
 449        struct fname *fname, *new_fn;
 450        struct dir_private_info *info;
 451        int len;
 452
 453        info = dir_file->private_data;
 454        p = &info->root.rb_node;
 455
 456        /* Create and allocate the fname structure */
 457        len = sizeof(struct fname) + ent_name->len + 1;
 458        new_fn = kzalloc(len, GFP_KERNEL);
 459        if (!new_fn)
 460                return -ENOMEM;
 461        new_fn->hash = hash;
 462        new_fn->minor_hash = minor_hash;
 463        new_fn->inode = le32_to_cpu(dirent->inode);
 464        new_fn->name_len = ent_name->len;
 465        new_fn->file_type = dirent->file_type;
 466        memcpy(new_fn->name, ent_name->name, ent_name->len);
 467
 468        while (*p) {
 469                parent = *p;
 470                fname = rb_entry(parent, struct fname, rb_hash);
 471
 472                /*
 473                 * If the hash and minor hash match up, then we put
 474                 * them on a linked list.  This rarely happens...
 475                 */
 476                if ((new_fn->hash == fname->hash) &&
 477                    (new_fn->minor_hash == fname->minor_hash)) {
 478                        new_fn->next = fname->next;
 479                        fname->next = new_fn;
 480                        return 0;
 481                }
 482
 483                if (new_fn->hash < fname->hash)
 484                        p = &(*p)->rb_left;
 485                else if (new_fn->hash > fname->hash)
 486                        p = &(*p)->rb_right;
 487                else if (new_fn->minor_hash < fname->minor_hash)
 488                        p = &(*p)->rb_left;
 489                else /* if (new_fn->minor_hash > fname->minor_hash) */
 490                        p = &(*p)->rb_right;
 491        }
 492
 493        rb_link_node(&new_fn->rb_hash, parent, p);
 494        rb_insert_color(&new_fn->rb_hash, &info->root);
 495        return 0;
 496}
 497
 498
 499
 500/*
 501 * This is a helper function for ext4_dx_readdir.  It calls filldir
 502 * for all entres on the fname linked list.  (Normally there is only
 503 * one entry on the linked list, unless there are 62 bit hash collisions.)
 504 */
 505static int call_filldir(struct file *file, struct dir_context *ctx,
 506                        struct fname *fname)
 507{
 508        struct dir_private_info *info = file->private_data;
 509        struct inode *inode = file_inode(file);
 510        struct super_block *sb = inode->i_sb;
 511
 512        if (!fname) {
 513                ext4_msg(sb, KERN_ERR, "%s:%d: inode #%lu: comm %s: "
 514                         "called with null fname?!?", __func__, __LINE__,
 515                         inode->i_ino, current->comm);
 516                return 0;
 517        }
 518        ctx->pos = hash2pos(file, fname->hash, fname->minor_hash);
 519        while (fname) {
 520                if (!dir_emit(ctx, fname->name,
 521                                fname->name_len,
 522                                fname->inode,
 523                                get_dtype(sb, fname->file_type))) {
 524                        info->extra_fname = fname;
 525                        return 1;
 526                }
 527                fname = fname->next;
 528        }
 529        return 0;
 530}
 531
 532static int ext4_dx_readdir(struct file *file, struct dir_context *ctx)
 533{
 534        struct dir_private_info *info = file->private_data;
 535        struct inode *inode = file_inode(file);
 536        struct fname *fname;
 537        int     ret;
 538
 539        if (!info) {
 540                info = ext4_htree_create_dir_info(file, ctx->pos);
 541                if (!info)
 542                        return -ENOMEM;
 543                file->private_data = info;
 544        }
 545
 546        if (ctx->pos == ext4_get_htree_eof(file))
 547                return 0;       /* EOF */
 548
 549        /* Some one has messed with f_pos; reset the world */
 550        if (info->last_pos != ctx->pos) {
 551                free_rb_tree_fname(&info->root);
 552                info->curr_node = NULL;
 553                info->extra_fname = NULL;
 554                info->curr_hash = pos2maj_hash(file, ctx->pos);
 555                info->curr_minor_hash = pos2min_hash(file, ctx->pos);
 556        }
 557
 558        /*
 559         * If there are any leftover names on the hash collision
 560         * chain, return them first.
 561         */
 562        if (info->extra_fname) {
 563                if (call_filldir(file, ctx, info->extra_fname))
 564                        goto finished;
 565                info->extra_fname = NULL;
 566                goto next_node;
 567        } else if (!info->curr_node)
 568                info->curr_node = rb_first(&info->root);
 569
 570        while (1) {
 571                /*
 572                 * Fill the rbtree if we have no more entries,
 573                 * or the inode has changed since we last read in the
 574                 * cached entries.
 575                 */
 576                if ((!info->curr_node) ||
 577                    !inode_eq_iversion(inode, file->f_version)) {
 578                        info->curr_node = NULL;
 579                        free_rb_tree_fname(&info->root);
 580                        file->f_version = inode_query_iversion(inode);
 581                        ret = ext4_htree_fill_tree(file, info->curr_hash,
 582                                                   info->curr_minor_hash,
 583                                                   &info->next_hash);
 584                        if (ret < 0)
 585                                return ret;
 586                        if (ret == 0) {
 587                                ctx->pos = ext4_get_htree_eof(file);
 588                                break;
 589                        }
 590                        info->curr_node = rb_first(&info->root);
 591                }
 592
 593                fname = rb_entry(info->curr_node, struct fname, rb_hash);
 594                info->curr_hash = fname->hash;
 595                info->curr_minor_hash = fname->minor_hash;
 596                if (call_filldir(file, ctx, fname))
 597                        break;
 598        next_node:
 599                info->curr_node = rb_next(info->curr_node);
 600                if (info->curr_node) {
 601                        fname = rb_entry(info->curr_node, struct fname,
 602                                         rb_hash);
 603                        info->curr_hash = fname->hash;
 604                        info->curr_minor_hash = fname->minor_hash;
 605                } else {
 606                        if (info->next_hash == ~0) {
 607                                ctx->pos = ext4_get_htree_eof(file);
 608                                break;
 609                        }
 610                        info->curr_hash = info->next_hash;
 611                        info->curr_minor_hash = 0;
 612                }
 613        }
 614finished:
 615        info->last_pos = ctx->pos;
 616        return 0;
 617}
 618
 619static int ext4_dir_open(struct inode * inode, struct file * filp)
 620{
 621        if (IS_ENCRYPTED(inode))
 622                return fscrypt_get_encryption_info(inode) ? -EACCES : 0;
 623        return 0;
 624}
 625
 626static int ext4_release_dir(struct inode *inode, struct file *filp)
 627{
 628        if (filp->private_data)
 629                ext4_htree_free_dir_info(filp->private_data);
 630
 631        return 0;
 632}
 633
 634int ext4_check_all_de(struct inode *dir, struct buffer_head *bh, void *buf,
 635                      int buf_size)
 636{
 637        struct ext4_dir_entry_2 *de;
 638        int rlen;
 639        unsigned int offset = 0;
 640        char *top;
 641
 642        de = (struct ext4_dir_entry_2 *)buf;
 643        top = buf + buf_size;
 644        while ((char *) de < top) {
 645                if (ext4_check_dir_entry(dir, NULL, de, bh,
 646                                         buf, buf_size, offset))
 647                        return -EFSCORRUPTED;
 648                rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
 649                de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
 650                offset += rlen;
 651        }
 652        if ((char *) de > top)
 653                return -EFSCORRUPTED;
 654
 655        return 0;
 656}
 657
 658const struct file_operations ext4_dir_operations = {
 659        .llseek         = ext4_dir_llseek,
 660        .read           = generic_read_dir,
 661        .iterate_shared = ext4_readdir,
 662        .unlocked_ioctl = ext4_ioctl,
 663#ifdef CONFIG_COMPAT
 664        .compat_ioctl   = ext4_compat_ioctl,
 665#endif
 666        .fsync          = ext4_sync_file,
 667        .open           = ext4_dir_open,
 668        .release        = ext4_release_dir,
 669};
 670
 671#ifdef CONFIG_UNICODE
 672static int ext4_d_compare(const struct dentry *dentry, unsigned int len,
 673                          const char *str, const struct qstr *name)
 674{
 675        struct qstr qstr = {.name = str, .len = len };
 676        const struct dentry *parent = READ_ONCE(dentry->d_parent);
 677        const struct inode *inode = READ_ONCE(parent->d_inode);
 678
 679        if (!inode || !IS_CASEFOLDED(inode) ||
 680            !EXT4_SB(inode->i_sb)->s_encoding) {
 681                if (len != name->len)
 682                        return -1;
 683                return memcmp(str, name->name, len);
 684        }
 685
 686        return ext4_ci_compare(inode, name, &qstr, false);
 687}
 688
 689static int ext4_d_hash(const struct dentry *dentry, struct qstr *str)
 690{
 691        const struct ext4_sb_info *sbi = EXT4_SB(dentry->d_sb);
 692        const struct unicode_map *um = sbi->s_encoding;
 693        const struct inode *inode = READ_ONCE(dentry->d_inode);
 694        unsigned char *norm;
 695        int len, ret = 0;
 696
 697        if (!inode || !IS_CASEFOLDED(inode) || !um)
 698                return 0;
 699
 700        norm = kmalloc(PATH_MAX, GFP_ATOMIC);
 701        if (!norm)
 702                return -ENOMEM;
 703
 704        len = utf8_casefold(um, str, norm, PATH_MAX);
 705        if (len < 0) {
 706                if (ext4_has_strict_mode(sbi))
 707                        ret = -EINVAL;
 708                goto out;
 709        }
 710        str->hash = full_name_hash(dentry, norm, len);
 711out:
 712        kfree(norm);
 713        return ret;
 714}
 715
 716const struct dentry_operations ext4_dentry_ops = {
 717        .d_hash = ext4_d_hash,
 718        .d_compare = ext4_d_compare,
 719};
 720#endif
 721